KR20080077409A - Clay film and method for producing same - Google Patents

Abstract

Disclosed is a transparent clay film wherein a clay and an additive are uniformly dispersed and the haze value hardly increases over time even when the film is left in the air. In addition, the transparent clay film hardly suffers from defects such as breakage and cracking. Also disclosed is a method for producing such a transparent clay film. Specifically, a clay dispersion is obtained by mixing a synthetic saponite as the clay and water as the solvent. Meanwhile, an additive-containing solution is obtained by mixing sodium polyacrylate as the additive and water as the solvent. Then, a uniform clay-containing solution is obtained by mixing the clay dispersion and the additive-containing solution. After that, the clay-containing solution is deaerated in vacuum, and the deaerated clay-containing solution is applied over a flat portion of the surface of a polypropylene tray. After drying, a thus-formed clay film is separated from the tray.

Description

Clay film and its manufacturing method {CLAY FILM AND METHOD FOR PRODUCING SAME}

The present invention relates to a clay film and a method for producing the same. The present invention also relates to an electronic paper, a substrate, and a gas barrier film composed of at least a portion of a clay film.

In general, various production processes are used under high temperature conditions in most chemical industries. In the piping connection part of these production lines, the measures which prevent the leakage of a liquid or a gas, for example by packing, welding, etc. are taken. Until now, the packing which was excellent in flexibility was made using the organic polymer material, asbestos, etc., for example. However, in the case of using an organic polymer material, its heat resistance is about 250 ° C. at the highest Teflon (registered trademark), and a metal packing must be used at a temperature higher than that. However, the metal packing has a problem that it is inferior in flexibility compared with the case where the organic polymer material is used, and the aggressiveness to the surface which faces a packing is strong. In addition, although the material containing asbestos is excellent in heat resistance and chemical resistance, it is a problem that asbestos is highly toxic to the human body, and development of alternative materials is urgently required.

On the other hand, in recent years, the manufacturing technology of flat panel displays (hereinafter, referred to as FPDs) including liquid crystal displays has advanced remarkably, and a thin display which is hardly obtainable in conventional CRTs has become a reality. Almost all current FPDs have devices formed on glass substrates, and practical FPDs using substrates other than glass substrates do not exist. The reason for this is that the glass substrate has high heat resistance, is suitable for forming a drive circuit or a member of a display requiring high temperature formation, a coefficient of linear expansion is small, and stresses applied to these drive circuits or a member can be suppressed, so that breakage or parts of the wiring can be suppressed. It is easy to extract light because it is transparent in the visible region, and the gas barrier property is high, and it can be used as a gas barrier material for preventing the ingress of oxygen or water vapor from the outside. Therefore, the thing which can maintain high vacuum is mentioned.

However, the glass substrate is inflexible and easily cracked. Moreover, the weight is heavy, and the deformation | transformation of a board | substrate and the difficulty of handling become a problem. In addition, the glass substrate cannot be used for flexible displays such as bent electronic paper, which is assumed to be bent and transported, and thus has a drawback in that the glass substrate is easily broken against impact and the device is easily damaged when dropped. Not very suitable for mobile use. From this point of view, the practical use of a substrate for display and a gas barrier film having heat resistance, linear expansion coefficient, transparency, gas barrier property, and the like equivalent to glass is required.

In addition, requests for higher density of component mounting are increasing for circuit boards on which electronic components constituting telephone products such as displays, portable telephone terminals, and computers are mounted. In addition, the demand for flexibility is also increasing due to the increase in the number of telephone products requiring rotation and deformation represented by mobile telephone terminals. Therefore, the demand and demand of a flexible circuit board and a copper clad laminated board are also increasing.

As a flexible circuit board, the board | substrate formed from resin, such as polyethylene terephthalate, polycarbonate, and polyimide, and the special glass epoxy board | substrate are used at present. By the way, when manufacturing the printed board which forms a circuit wiring by printing or application | coating using electroconductive ink, such as electroconductive paste, in order to obtain the wiring of high electrical conductivity, it is generally required to bake at high temperature 300 degreeC or more after apply | coating electroconductive ink. However, in the case of a flexible circuit board using a substrate formed of the resin as described above, since the heat resistance of the resin is low and the coefficient of linear expansion is generally large, the above-described high temperature baking cannot be performed and must be performed at a relatively low temperature.

However, since the sintering of the conductive ink does not proceed sufficiently at low temperatures, there is a problem that the conductivity is generally inferior to the wiring obtained by metal foil or vacuum deposition. Polyimide resins are relatively high in heat resistance, but because of their high cost, it is difficult to use them for applications where cost is most important, such as RFID (Radio frequency identification) tags. From this point of view, the practical use of an inexpensive flexible printed circuit board having insulation and high heat resistance and flame retardancy is required.

On the other hand, clay is a mineral that exists in large quantities in nature, is inexpensive, harmless to the human body, and does not burn. In addition, the dark brown "soil color" found in most natural clays is often derived from impurities such as organic matter and iron, but a colorless clay free of these impurities can be obtained by chemical synthesis. Clay minerals are largely divided into crystalline minerals and amorphous minerals, and all of the crystalline portions are phyllosilicates, meaning "leaf phase," and have a layered structure due to their leaf shapes. In other words, minerals commonly referred to as layered silicates fall into the category of minerals defined as clay. Most clays have one or three layers of tetrahedral or octahedral sheets of about 0.2 nm to about 0.5 nm in thickness composed mainly of oxygen (O), silicon (Si), and aluminum (Al). It consists of a sheet-like layered inorganic compound with a large aspect ratio which has the magnitude | size of the major axis direction about nm-5 micrometers.

The tetrahedral sheet and octahedral sheet in such layered silicate will be described in more detail. The tetrahedral sheet is formed by coordinating four O's in Si to form tetrahedrons of SiO ₄ , and the tetrahedrons share the three O's and are connected in a hexagonal network. In some cases, Si may form tetrahedrons of AlO ₄ instead of Al. In addition to this, iron (Fe) and the like may also form tetrahedrons. In contrast, an octahedral sheet is formed by coordinating six hydroxyl groups (OH) or O to Al, and may also be formed of magnesium (Mg), Fe, or the like instead of Al. In addition, in a tetrahedral sheet, Si is substituted by Al etc., or in an octahedral sheet, Al is substituted by Mg etc., an oversufficiency generate | occur | produces a sheet, and a sheet | seat often has a permanent charge. It is also possible to introduce into the tetrahedral sheet or the octahedral sheet artificially while controlling other elements, thereby attempting to change various physical properties such as magnetic properties and optical properties.

By these sheets or by laminating and bonding these sheets, various layered inorganic compounds are produced. In the present invention, the unit layer to which the sheet is bound is defined as clay crystal. For example, a series of minerals (for example, magadiite) generally called layered polysilicic acid can be cited as consisting of clay crystals having only tetrahedral sheets as a unit layer. On the other hand, it is known that clay minerals called hydrotalcites are formed by having negative ions such as carbonate ions between a positively charged octahedral sheet and an octahedral sheet.

Clay minerals in which clay crystals, which are unit layers as minerals, are formed by combining a tetrahedral sheet and an octahedral sheet 1: 1 to be laminated are generally called kaolin minerals, and kaolinite and halosite are famous. On the other hand, the tetrahedral sheet and the octahedral sheet are combined 2: 1 and laminated (i.e., tetrahedral sheet-octahedral sheet-tetrahedral sheet), and the clay mineral in which the clay crystal as a unit layer is formed includes pyrophyllite, Talc, smectite clay, vermiculite, mica clay minerals, and the like. In particular, clays belonging to the smectite family (e.g. montmorillonite, saponite, hectorite, stevensite, etc.) are uniformly dispersed in high polar solvents (especially water), such as water or alcohol, in the case of the general ones having inorganic cations between layers. It is said that it is possible to make it possible to disperse | distribute to one piece of a unit layer separately in a high polar solvent separately (for example, refer nonpatent literature 1).

As one of the methods of using clays described above, extensive research has been conducted on nanocomposite materials in which a small amount of clay (usually about 5% by mass or less) is added to resins, and some of them have been put into practical use (for example, non-patent literature). 2). In the system of the nanocomposite material in which small amounts of these clays are added, the effect of improving the strength, flame retardancy, or the gas barrier property has been confirmed.

However, in these nanocomposite materials, since the ratio of clay is small, the gas barrier property and the flame retardance were not improved substantially. For example, in terms of gas barrier properties, there are cases where the permeability of the gas is about one minute due to the addition of clay, but there are few cases in which the gas barrier property is improved by more than one order. In addition, natural montmorillonite or synthetic mica having a large crystal size is often used for the purpose of lengthening the gas migration path when gas is permeated to improve gas barrier properties. In this case, yellow coloration derived from natural montmorillonite or Due to factors such as scattering of light derived from a large size of synthetic mica, it was difficult to obtain a film having a small, colorless, high transparency that can be used for a display or the like. Similarly, when the amount of clay added is small, it is difficult to significantly improve physical properties other than gas barrier properties, such as heat resistance or dimensional stability upon temperature change, and the essential properties of clay having high heat resistance and excellent dimensional stability are fully utilized. It was hard to say.

In order to improve gas barrier property and to suppress light scattering and to improve transparency, it is considered important to form a nanocomposite body with a dense and highly oriented layer of clay crystals. It is thought that dimensional stability is also improved by this. Background Art Conventionally, for example, it is known that a film in which the orientation of particles is aligned is formed by spreading a dispersion of clay on a glass plate and then standing and drying, and the positive orientation sample of the X-ray diffraction method has been adjusted by this film formation (Non Patent Literature). 3). Moreover, manufacture of the clay thin film which applied the Langmuir-Blodgett method is performed (for example, refer nonpatent literature 4). However, in this method, the clay thin film is formed on the substrate surface made of a material such as glass, and is not a clay thin film having strength as a freestanding film.

In addition, conventionally, various methods of adjusting a functional clay thin film and the like have been reported. For example, a method for producing a transparent clay film (see Patent Document 1) consisting of film-forming and drying a water dispersion of a hydrotalcite-based interlayer compound, and promoting the reaction by using a reaction of a layered clay mineral with a phosphoric acid or a phosphate group Method of manufacturing a layered clay mineral thin film in which the bonding structure of the layered clay mineral is fixed by performing heat treatment (see Patent Document 2), and an aqueous composition for coating treatment containing a complex compound of smectite clay mineral and divalent or more metal (Patent Document There are many examples, including 3). However, the clay-like clay-forms in these prior art documents were all formed on a certain support, and were not clay alignment films having a mechanical strength usable as a self-supporting film and highly laminated stacks of clay particles.

Moreover, as a transparent film | membrane using clay, the water dispersion liquid of synthetic saponite or synthetic hectorite was coat | covered on the film, and the example used as a phase difference film of a liquid crystal display. This transparent film is provided with a phase difference with respect to propagation of light by effectively utilizing a large difference between the in-plane direction of the sheet crystal and the sheet thickness direction of the clay crystals of the synthetic saponite or the synthetic hectorite. Some of such transparent films are obtained by peeling a clay film formed on a support (see Patent Document 4).

However, in the clay film obtained by peeling from the support described in Patent Document 4, the amount of clay contained in the clay film estimated to have the mechanical strength available as a freestanding film is about 47% by mass, and at least half of the additives such as polymers Is done. Therefore, it is difficult to say that the film mainly contains clay, and gas barrier properties and the like are not sufficient. In addition, if a thick film is formed by increasing the amount of clay, the phase difference between the in-plane direction and the thickness direction of the film becomes excessively large, and the suitability of the retardation film for liquid crystal display is lost. Therefore, the ratio of clay can not be reduced when making a thick film having independence. There was no necessity.

In addition, a high strength and water resistant transparent clay film made of transparent polyimide and hydrophobic clay has also been developed. This hydrophobic clay is hydrophobic clay which improved the dispersibility to the organic solvent by replacing the inorganic ion which the smectite hydrophilic clay disperse | distributed in water with organic ammonium salt etc. (refer patent document 5). Unlike the clay film described in Patent Document 4 described above, this clay film does not dissolve even if it comes into contact with water.

However, Patent Document 5 discloses that clay is partially aggregated in the manufacturing process unless the content of clay is less than 20% by mass. As a result, it is shown that haze increases and it becomes difficult to be transparent (50% or more by a haze value), and the fall of toughness also becomes remarkable. That is, these are equivalent to the conventional nanocomposite body in which a small amount of clay is added, and it is difficult to say that the film mainly increases the gas barrier property and the dimensional stability by using clay as the main body.

In this situation, the present inventors have made various attempts to manufacture a clay alignment layer in which the layers of the clay crystals are closely and highly oriented, and in the process, the clay membrane having strength that can be used as a self-supporting film in which the clay particles are oriented is What was obtained by the same method was found. That is, the clay dispersion is adjusted to obtain a uniform dispersion, and the dispersion is allowed to stand horizontally to deposit clay particles, and various solid-liquid separation methods (e.g., centrifugal separation, filtration, vacuum drying, and freeze vacuum drying) of the liquid as a dispersion medium. Or by evaporation by heating) to form a film, followed by peeling from the support (see Patent Document 6).

In addition, by using a clay-containing liquid in which not only clay but also a small amount of additive is added to the clay dispersion, the flexibility and strength of the clay film can be increased (see Patent Document 7), and a clay paste having a high solids ratio of clay-containing liquid is used. By doing so, it was found that a clay film can be produced in a short time (see Patent Document 8), and a transparent clay film can be produced in a visible light region mainly containing clay by using synthetic clay.

In addition, clay films mainly made of clay and highly orientated in layers of clay crystals have (1) high heat resistance compared to those of conventional clays, and (2) inorganic gases such as oxygen and hydrogen. Has high gas barrier properties, (3) no pinholes in the film, (4) flexibility, (5) chemical resistance, (6) low coefficient of linear expansion, (7) flame retardancy, (8 By confirming that it has the characteristic of having insulation, it found that it is suitable for the material which comprises the packing mentioned above, and the electronic material use, such as a display member and a flexible circuit board mentioned above.

However, in the conventional method, when an additive is added and mixed in a clay dispersion, clay may aggregate by the additive. Alternatively, when the viscosity of the clay dispersion rises rapidly, additives are not uniformly dispersed in the clay dispersion, and non-uniform aggregates are generated in the clay dispersion, or when the clay film is agglomerated and precipitated in a particulate form, the clay film becomes non-uniform. there was. In addition, even when the solubility or dispersibility of the additive in the dispersing solvent that preferably disperses the clay is low, the additive is not uniformly dispersed uniformly, and similar problems may occur. As a result, in the transparent clay film, problems such as low transparency areas are formed in the surface, or clays or additives aggregated in the form of particles scatter light, which increases haze. Even if it wanted to improve the physical property of the additive, the kind and addition amount of an additive may be restrict | limited.

In addition, by increasing the ratio of clay in the clay film, it has been found that when the layer of clay crystal is dense and highly oriented, it is difficult for gaseous components remaining in the clay film to escape from the clay film. That is, when bubbles (voids) derived from gas components mixed in the clay-containing liquid are contained in the clay film, the bubbles rapidly expand when heated rapidly, causing circular swelling on the surface of the clay film, thereby destroying the clay film. In the case of the transparent clay film, there existed a problem that a space | gap became the cause of the internal scattering of light, and the clay film became cloudy and a haze increased.

Since the gaseous components remaining in the clay film are derived from the gaseous components contained in the clay-containing liquid, it was thought to be important to remove the gaseous components in the clay-containing liquid, form them on a support, and dry them to obtain a clay membrane. Especially in the case of producing a clay film having a large proportion of clay, that is, in the case of a large clay ratio in the clay dispersion, the viscosity and thixotropy derived from clay are remarkably expressed. Thus, the fluidity of the clay dispersion is lowered to remove these gas components. It becomes difficult. Therefore, reducing the gaseous components in the clay-containing liquid is an important subject for the production of clay films with a large proportion of clay, and development of an effective method has been required.

In addition, as a method of dispersing the clay particles in a solvent, a method of shaking with a dispersing device or the like is generally used, but especially when the solid content concentration is high, it has been necessary to shake with a dispersing device for a long time. In addition, since there is generally an upper limit to the concentration of the clay dispersion bound to the liquid limit of clay, it was difficult to increase the solid content concentration of the clay dispersion beyond the value set as the liquid limit.

In addition, when the conventional clay and additives made of clay and left for a long time in the air have a haze, the clay film is clouded, and transparency may decrease. This increase in haze over time occurs when the unevenness of the surface of the clay film increases with time.

In order to reduce the haze and improve the transparency of the clay film, the surface was polished and smoothed, or a clay film was formed by providing a layer having a composition different from that of clay such as a transparent resin. In addition to the need to do so, there are problems such as the strength and durability of the clay film, so that physical polishing was difficult. In addition, since the heat resistance temperature of the imparting layer is low, the heat resistance of the clay film is greatly reduced, or because the coefficient of linear expansion with respect to the temperature change is different from that of the clay film, the film is warped or defects are generated in the clay film due to stress. There was a problem. Thus, there existed many problems in the method of giving the layer of a composition different from clay, such as resin.

In addition, in the case of preparing a clay membrane by removing the solvent by a simple and common method of heating evaporation, the volumetric shrinkage occurs in the process of solidifying and drying the clay dispersion according to the evaporation of the solvent. According to the stresses. Therefore, when the strength of a clay film cannot withstand this stress, there existed a problem that a clay film may crack in a drying process.

Therefore, the present invention solves the problems of the prior art as described above, clay and additives are uniformly dispersed, cracks, cracks and other defects are less likely to occur, the clay film having a strength that can be used as a freestanding film and its It is a subject to provide a manufacturing method. In addition, it is another object of the present invention to provide a transparent clay film having a high light transmittance, a small haze, and hardly causing an increase in haze over time even when left in the air. Moreover, it is also a subject to provide the electronic paper, a board | substrate, and a gas barrier film provided with such a clay film.

Patent document: Japanese Patent Publication No. 6-year 95290

Patent Document 2: Japanese Patent Publication No. 5 Years Publication No. 254824

Patent Document 3: Japanese Patent Laid-Open No. 2002 No. 30255

Patent Document 4: Japanese Patent Publication No. 3070544

Patent Document 5: Japanese Patent Laid-Open Publication No. 2006 37079

Patent Document 6: Japanese Patent Laid-Open No. 2005 No. 104133

Patent Document 7: Japanese Patent Publication No. 2005313313

Patent Document 8: Japanese Patent Laid-Open Publication No. 2006 265088

[Non-Patent Document 1] Capital Discourses, "An Invitation to Clay Science-An Approach and Attraction of Clays", Japan, Mitomo Publishing Co., p. 6 (2000)

[Non-Patent Document 2] Kiyoshi Nakajo, `` Product Development of Polymer-Based Nanocomposites '', Japanese, Frontier Publishing, p. 25-90 (2004)

[Non-Patent Document 3] Haruo Shiromizu, "The Clay Mineralogy-The Basics of Clay Science", Japan, Asakura Bookstore, p.57 (1988)

[Non-Patent Document 4] Yasushi Umezawa, "Clay Science", Japan, Vol. 42, No. 4, 218-222 (2003).

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, this invention consists of the following structures. That is, in the method for producing a clay film of the present invention, a clay dispersion liquid in which clay is dispersed in a solvent and an additive containing liquid in which an additive is dispersed or dissolved in a solvent are prepared, respectively, and the ratio of the additive in the total amount of the clay and the additive is A clay-containing liquid adjusting step of mixing the clay dispersion and the additive-containing liquid so as to be more than 0% by mass and 50% by mass or less, thereby obtaining a clay-containing liquid, and after disposing the clay-containing liquid on the surface of the support, removing the solvent It has a drying process to dry. It is characterized by the above-mentioned.

Moreover, the manufacturing method of the clay film of this invention prepares the clay dispersion liquid which disperse | distributed the clay to the solvent, and the additive containing liquid which disperse | distributed or dissolved the additive in the solvent, respectively, and the ratio of the said additive in the total amount of the said clay and the said additive is A clay-containing liquid adjusting step of mixing the clay dispersion and the additive-containing liquid so as to be more than 0% by mass and 30% by mass or less, thereby obtaining a clay-containing liquid, and after disposing the clay-containing liquid on the surface of the support, removing the solvent It has a drying process to dry. It is characterized by the above-mentioned.

In the manufacturing method of such a clay film of this invention, it is preferable to have a degassing process which reduces the gas contained in the said clay containing liquid. Moreover, you may have the peeling process which peels the dry matter obtained by the said drying process from the said support body.

Moreover, in the said clay containing liquid adjustment process, it is preferable to obtain the said clay containing liquid by mixing the said clay dispersion liquid and the said additive containing liquid at the temperature higher than normal temperature.

In addition, the clay-containing liquid is brought to a temperature higher than normal temperature and under reduced pressure, it is preferable to reduce the gas contained in the clay-containing liquid, and the clay-containing liquid to a temperature higher than normal temperature and stirred under reduced pressure. It is more preferable to reduce the gas contained in the clay-containing liquid by doing so.

Moreover, in the manufacturing method of the clay film of this invention, the said support body may have flexibility, and in that case, after drying the said support body in a deformable state, it is preferable to peel the said dried material from the said support body. The support may be a resin film. The support may be subjected to an easy peeling treatment or a water repellent treatment.

Moreover, the manufacturing method of the clay film of this invention may have the redrying process of arrange | positioning and redrying the liquid which swells the said clay or the liquid which melt | dissolves or disperse | distributes the said additive on the surface of the dry matter obtained by the said drying process. At this time, the liquid may be disposed on the surface of the dried product by dipping in the liquid, or the liquid may be disposed on the surface of the dried product by spraying the liquid.

In the redrying step, the liquid may be redried after arranging the liquid on the surface to contact the smoothing member having at least a portion near the surface with a smooth member having a smooth surface to smooth the surface. The smoothing member may be flexible and deformable. In that case, it is preferable to redry the liquid in a state in which the dried material is in contact with the smoothing member.

Moreover, in the manufacturing method of the clay film of this invention, it is preferable that the said clay is hydrophilic clay which has high affinity for water and is easy to disperse in water. In addition, the clay may be hydrophobic clay which has high affinity for an organic solvent and is easy to disperse in an organic solvent. In the case of hydrophobic clays, hydrophobic clays having improved affinity and dispersibility in an organic solvent by exchanging inorganic ions included in hydrophilic clays with organic ions are preferable. The organic ions are ammonium ions, phosphonium ions, or imidazolium. It is preferable to contain at least one of the ions.

Moreover, in the manufacturing method of the clay film of this invention, the clay film obtained may be transparent.

Moreover, the clay film of this invention is a clay film manufactured by the manufacturing method of the clay film of this invention as mentioned above, It is characterized by layered clay crystals laminated | stacked in the film thickness direction. And it is preferable that the average linear expansion coefficient of 30 degreeC-250 degreeC is 10 ppm or less.

In addition, the clay film of the present invention preferably has a haze of 5% or less, a total light transmittance of 85% or more, and a light transmittance of 85% or more and 95% or less in a wavelength range of 400 nm or more and 800 nm or less. It is more preferable that haze is 2% or less, and it is still more preferable that haze is less than 1%. Moreover, it is preferable that the time-dependent change of haze in the environment of 24 degreeC, 1 atmosphere, and 45% of humidity is -2% or more and 2% or less. Moreover, it is preferable that the clay film of this invention is thicker than 15 micrometers.

In addition, the electronic paper of the present invention is characterized in that at least part of the clay film obtained by the method for producing a clay film of the present invention as described above, or the clay film of the present invention as described above is constituted.

Further, the flexible printed circuit board of the present invention is characterized in that at least part of the clay film obtained by the method for producing a clay film of the present invention as described above, or the clay film of the present invention as described above is constituted.

Further, the flexible printed circuit board of the present invention is characterized in that at least part of the clay film obtained by the method for producing a clay film of the present invention as described above, or the clay film of the present invention as described above is constituted.

In addition, the substrate of the present invention is a substrate having a gas barrier property, in which an electronic device including a non-light emitting organic semiconductor or an amorphous inorganic semiconductor is mounted, and the clay film obtained by the method for producing a clay film of the present invention as described above, Or at least a portion of the clay film of the present invention as described above is characterized in that it is configured.

In addition, the gas barrier film of this invention is a gas barrier film which protects the electronic device provided with a non-light emitting organic semiconductor or an amorphous inorganic semiconductor from a gas, The clay film obtained by the manufacturing method of the clay film of this invention mentioned above, or At least a portion of the clay film of the present invention as described above is characterized in that the configuration.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the ultraviolet visible absorption spectrum of a clay film.

2 is a diagram showing an X-ray diffraction spectrum of a transparent clay film.

3 is a view showing a cross-sectional photograph of the transparent clay film by TEM.

4 is a view showing a cross-sectional photograph of the clay film by SEM.

5 is a diagram showing an X-ray diffraction spectrum of a clay film.

6 is a view showing a cross-sectional photograph of the clay film by TEM.

7 is a view showing a cross-sectional photograph of the clay film by SEM.

Although the clay film of this invention is a film | membrane which consists of clay and an additive, the ratio of the additive in the total amount of a clay and an additive needs to be more than 0 mass% and 50 mass% or less, and it is preferable that it is more than 0 mass% and 40 mass% or less. And in order to acquire more preferable characteristics as a clay film, it is more preferable that the ratio of an additive is more than 0 mass% and 30 mass% or less, It is more preferable that it is more than 0 mass% and less than 30 mass%, It is more than 0 mass% and 15 mass% or less It is especially preferable, and it is most preferable that it is more than 0 mass% and 10 mass% or less.

When the proportion of the additive is large, the amount of the additive that enters between the unit layers of the clay increases, and the gap between the layers of the clay crystal is greatly increased, and also, the transparency is lowered due to the disturbance of the orientation of the clay crystal. Various problems such as lowering of heat resistance, lowering of gas barrier property by gas permeation through additives, and increasing dimensional change amount of clay film due to temperature change occur, and the difference between the nanocomposites and the conventional nanocomposites is largely lost depending on the physical properties. In some cases. If the proportion of the additive is 50% by mass or less (particularly 30% by mass or less), a characteristic (for example, a low coefficient of linear expansion or a high gas barrier property) can be obtained by drawing a line with a conventional nanocomposite having a low proportion of clay. Can be.

Generally, a clay film is obtained by disposing a clay-containing liquid containing only clay or a clay and an additive on the surface of a support and drying it. The role of the additive in the clay film varies depending on the function and the application to be expressed. However, since it is generally difficult to obtain the strength available as a self-supporting film only with clay, the additive is required to function as a strength at least. When the average aspect ratio of clay crystals is large, for example, when natural montmorillonite having an average aspect ratio of 300 or more is used, a clay membrane having a strength usable as a self-supporting membrane can be obtained without an additive, but the obtained clay membrane is fragile and an additive is used. Very preferred. Also in the present invention, the primary role of the additive is to improve the strength of the clay film.

Therefore, when the ratio of the additive (for example, a polymer or a polymerizable monomer) which has a strength improvement effect is increased, the intensity | strength of a clay film usually improves also. When the ratio of additives is high (more than 50% by mass), as in conventional nanocomposite bodies, the orientation of clay crystals, the intercalation of additives (where the target substance is inserted between the layers of clay crystals), and the layer of clay crystals Even if some factors such as the degree of peeling, the degree of dispersion, and the removal of gaseous components incorporated into the clay-containing liquid are not considered, the strength and the degree of transparency that can be peeled off from the support may be due to the effect of imparting strength by the additive. There was a case.

However, in the case of producing a clay film having a large proportion of clay, especially when the proportion of clay is 70% by mass or more, in the conventionally known method, the clay or additives are not uniformly dispersed in the clay-containing liquid sufficiently or mixed in the clay-containing liquid. Since a gas component cannot fully be removed, the clay film obtained may become nonuniform. As a result, the mechanical strength and flexibility of the clay membrane may be insufficient. In addition, aggregation may occur due to the addition of an additive or an increase in the solid content concentration in the clay dispersion, resulting in insufficient transparency in the transparent clay film. In such a case, in order to improve the transparency, it is considered to take measures such as providing a layer having a composition different from clay such as a surface smoothing layer, but the heat resistance is lowered by increasing the manufacturing process or forming the imparting layer. There was a possibility that problems such as Moreover, even if such measures are taken, the fall of the physical property by the nonuniform structure which generate | occur | produced inside the clay film cannot be avoided.

Thus, the inventors of the present invention have found an optimal method for producing clay membranes capable of obtaining clay membranes in which clay or additives are uniformly dispersed as a result of earnestly examining in order to solve the above problems. That is, the manufacturing method of the clay film of this invention prepares (a) the clay dispersion liquid which disperse | distributed the clay to the solvent, and the additive containing liquid which disperse | distributed or dissolved the additive in the solvent, respectively, and the said additive in the total amount of the said clay and the said additive A clay-containing liquid adjusting step of mixing the clay dispersion and the additive-containing liquid to obtain a clay-containing liquid so that the ratio is more than 0% by mass and 50% by mass or less, and (b) disposing the clay-containing liquid on the surface of the support. It has a drying process which removes and dries the said solvent after that, It is characterized by the above-mentioned.

Moreover, the clay film obtained can be made transparent by selecting the kind of clay and an additive suitably. In addition, in this invention, transparent means that the light transmittance in the wavelength range whose total light transmittance is 70% or more, haze is 5% or less, 400 nm or more and 800 nm or less is 75% or more and 95% or less. However, this transparency is minimal, and the total light transmittance is preferably 80% or more, more preferably 85% or more, and even more preferably 88% or more. Moreover, it is preferable that the value of haze is 3% or less, It is more preferable that it is 2% or less, It is still more preferable that it is less than 1%. The light transmittance in the wavelength range of 400 nm or more and 800 nm or less is preferably 80% or more and 95% or less, and more preferably 85% or more and 95% or less. In addition, total light transmittance here and the haze are the test method of the total light transmittance of the plastic transparent material prescribed | regulated to Japanese Industrial Standards JIS K 7361, the optical test method of plastic JIS K 7105, the method of obtaining the haze of a plastic transparent material JIS K It was obtained in accordance with 7136.

Conventionally, when manufacturing the clay film obtained by the manufacturing method of the clay film of this invention, even if the ratio of clay is 70 mass% or more, the additive was added directly to the clay dispersion liquid which disperse | distributed the clay to the solvent, and the clay containing liquid was prepared. In this method, however, the higher the solids concentration of clay in the clay dispersion, the higher the viscosity of the clay dispersion is, the thixotropy becomes remarkable and the fluidity of the clay dispersion is remarkably lowered. Thus, additives are uniformly added to the clay-containing liquid. It is difficult to disperse or dissolve. In particular, it is more difficult in the case of the additive (for example, polyacrylate) which has the effect | action which thickens a clay containing liquid by adding.

On the other hand, the method of the present invention separately prepares a clay dispersion liquid in which clay is dispersed in a solvent, and an additive containing liquid in which an additive is dispersed or dissolved in a solvent, and mixes both to prepare a clay-containing liquid. Even additives exhibiting a thickening effect in the process or dispersion process, or additives having low dispersibility or solubility in a solvent used to disperse the clay, can be uniformly dispersed in the clay-containing liquid. Therefore, the kind and amount of additive which can be used are hardly restrict | limited. Moreover, since clay and an additive are mixed in the state which fully disperse | distributed or melt | dissolved, respectively, it is suppressed that a clay aggregates and the nonuniform lump is formed by the action by an additive.

In this method, it is preferable to prepare a clay dispersion and an additive-containing liquid by dispersing or dissolving the clay and the additive in a solvent at a temperature higher than normal temperature. By doing so, the additive can be dispersed or dissolved more uniformly and at a high concentration. Moreover, it is preferable to obtain a clay containing liquid by mixing a clay dispersion liquid and an additive containing liquid at temperature higher than normal temperature. By doing so, the clay is more uniformly dispersed, the additive is more uniformly dispersed or dissolved, and a clay-containing liquid having a high solid content concentration can be prepared.

As a method of preparing a clay dispersion and an additive-containing liquid by dispersing or dissolving the clay or the additive in a solvent at a temperature higher than the normal temperature, the clay or the additive is added to a solvent and heated by a method such as a heater, a warm air, a hot bath, and then stirred or agitated. Method of mixing by mixing, shaking, stirring by heating while mixing in the above method, mixing by stirring and shaking while applying energy to an ultrasonic dispersion device, a homogenizer, etc. while heating the additive-containing liquid itself. have.

In the present invention, when mixing the clay dispersion and the additive-containing liquid may be mixed at room temperature, the method of preparing a clay-containing liquid by mixing the clay dispersion and the additive-containing liquid at a temperature higher than the normal temperature to produce a uniform clay-containing liquid In addition, it is more preferable at the point which raises solid content concentration of a clay containing liquid. As such a method, a clay dispersion liquid and an additive-containing liquid are mixed and heated by a method such as a heater, warm air, or hot water, followed by mixing by stirring and shaking, a method of mixing by stirring and shaking while heating by the above method, and an ultrasonic dispersion device. , By mixing with stirring and shaking while applying energy to a homogenizer and heating the clay-containing liquid itself.

Moreover, one type of clay contained in a clay dispersion liquid may be used, and two or more types of clays may be mixed and used for it. Similarly, one type of additives contained in the additive-containing liquid may be used, or two or more types of clays may be mixed and used. Moreover, a clay containing liquid may be produced using two or more types of clay dispersion liquids from which a kind of clay etc. differ, and a clay containing liquid may be prepared using two or more types of additive containing liquids from which a kind of additive etc. are different. Alternatively, a clay-containing liquid may be prepared by mixing a plurality of kinds of clay dispersion liquids and a plurality of kinds of additive-containing liquids, respectively.

Thus, by adjusting each liquid at a temperature higher than room temperature, a clay-containing liquid in which clay or additives are more uniformly dispersed is obtained, thereby suppressing the formation of aggregates and adding additives on average between layers of clay crystals in a clay film forming process. It can be intercalated, and as a result, a clay film having sufficient mechanical strength and flexibility can be produced, and sufficient transparency can be imparted to the transparent clay film.

In addition, it is possible to increase the solid content concentration of the clay-containing liquid by mixing the clay and the additive with the solvent at a temperature higher than normal temperature, respectively. When the solid content concentration of a clay containing liquid is made high, it becomes easy to shorten a drying time or to manufacture a thick clay film. In addition, the low-viscosity clay-containing liquid can only be disposed on a horizontal plane perpendicular to the direction of gravity in the surface of the support, and flows down when disposed on an inclined surface. However, when the solid content concentration of the clay-containing liquid is increased to form a paste, It can also be arranged on the inclined surface. Moreover, since the fluidity | liquidity falls and the clay containing liquid can be prevented from flowing out from a support body, it is not necessary to carry out the study for prevention of outflow to a support body (for example, it is unnecessary to form a frame etc.).

In this invention, the method of using the container which rotates while revolving around a shaft can be used for mixing in preparation of a clay dispersion liquid, an additive containing liquid, and a clay containing liquid. That is, in manufacturing the clay film which consists of clay and an additive, it is a method of preparing a clay containing liquid by performing at least one of the preparation of a clay dispersion liquid, an additive containing liquid, and a clay containing liquid using the said container.

The mixing method in the preparation of the clay dispersion, the additive-containing liquid and the clay-containing liquid is not particularly limited as long as it is possible to sufficiently disperse the clay and the additive. However, the method of using the container is dispersed by a strong stirring force and a degassing ability. Alternatively, dissolution can be performed in a short time, and stirring is possible even in the gelled state beyond the liquid limit, which is very preferable for obtaining a clay-containing liquid having a high solid content concentration.

In particular, when the inside of a container is made into reduced pressure, such as a vacuum, and a clay containing liquid is stirred under reduced pressure, vacuum degassing can be performed simultaneously with mixing. Therefore, the degassing of the clay-containing liquid which is difficult to reduce the gas component mixed because of high solid content concentration and high viscosity can be performed sufficiently and efficiently.

Moreover, you may manufacture a clay film by the method of combining the above-mentioned several method.

In the clay film manufactured by the manufacturing method of this invention, when bubble (pore) is mixed when the ratio of an additive is 30 mass% or less, a bubble expands and destroys a clay film at the time of heat drying, or a light ray in a transparent film There is a possibility that problems such as transparency may be lowered due to scattering. In general, the viscosity of the clay-containing liquid increases as the solid content concentration increases, and the thixotropy becomes stronger. Therefore, when the stirring is stopped, the fluidity tends to be lost. As a result, it becomes difficult to remove the gas component mixed in the clay-containing liquid. In the clay-containing liquid having a solid content concentration at which a practical drying rate is obtained, this tendency is particularly strong, and it is difficult to reduce the gas component incorporated into the clay-containing liquid without any removal process.

In addition, in the clay film having a high ratio of clay, since the clay crystals are densely aligned and laminated, the gas barrier property is improved, and as a result, it is difficult to remove bubbles remaining in the clay film during film formation. Therefore, the process of fully removing the gas component contained in a clay containing liquid is very important, and it becomes an almost essential process in the clay film with a high ratio of clay.

Moreover, in order to provide the strength which can be used as a self-supporting film to the clay film with a high ratio of clay, the film thickness more than a certain grade is required. It is preferable that the thickness of a clay film is thicker than 10 micrometers, It is more preferable that it is thicker than 15 micrometers, It is more preferable that it is thicker than 20 micrometers, It is especially preferable that it is thicker than 30 micrometers, It is most preferable that it is thicker than 50 micrometers. This is very different from the use of the coating film which is effective in most cases even when the film thickness of several micrometers or less is unnecessary because of independence.

However, as the thickness of the clay film becomes thicker as described above in order to increase the strength, the gaseous components mixed into the clay-containing liquid are less likely to be removed from the clay film at the time of film formation, and are more likely to remain inside the clay film. This indicates that as the film thickness increases, defects due to bubbles remaining inside the clay film tend to cause a decrease in transparency due to scattering of light, or damage to the clay film during heating.

In order to increase the thickness of the clay film to be obtained, one of a method of increasing the clay concentration of the clay-containing liquid and a method of thickening the liquid film of the clay-containing liquid disposed on the support are usually considered. In the case of the former method, the viscosity of the clay-containing liquid increases with increasing solid concentration of the clay, and the thixotropy also becomes remarkable, so that the fluidity of the clay-containing liquid decreases. It becomes important to perform enough. In addition, even in the latter method, when the thickness of the liquid film disposed on the support becomes thicker, the amount of the gas component mixed therein increases, so it is important to sufficiently remove the gas component mixed in any way.

As a method of sufficiently removing the gas component contained in such a clay-containing liquid, a method of separating the gas component from the clay-containing liquid by centrifugation may be preferable, but a method of vacuum degassing by placing the clay-containing liquid under reduced pressure is particularly preferable. . At this time, if the viscosity is lowered by bringing the clay-containing liquid to a temperature higher than the normal temperature, even a clay-containing liquid having a high solid content concentration can be degassed well. That is, before arranging the clay-containing liquid on the surface of the support, it is preferable to keep the clay-containing liquid at a temperature higher than normal temperature and to remove bubbles contained in the clay-containing liquid under reduced pressure. At this time, if the clay-containing liquid is stirred under reduced pressure, the residual gas inside the clay-containing liquid is moved to the vicinity of the liquid surface to be easily discharged from the clay-containing liquid, and the expression of thixotropy can be suppressed, so that the clay-containing liquid can be suppressed. Since the increase of the viscosity can be suppressed, the degassing effect is further improved.

When degassing at a high temperature, the viscosity decreases as described above, so that degassing can be performed satisfactorily, but since the solvent of the clay-containing liquid tends to evaporate during degassing, in particular, the solid concentration near the surface of the liquid where the solvent evaporates. Is likely to rise, and as a result, precipitation of solids is likely to occur. Therefore, by performing degassing with further stirring, a local solid content concentration does not raise in a clay containing liquid, and a viscosity can be prevented from rising by thixotropy, and degassing can be performed at high temperature preferably.

The degassing operation as described above may be performed after the clay-containing liquid is heated by a method such as a heater, a warm air, a hot bath, or the like, or may be performed while heating by the above-described method, and energy is supplied to the clay by an ultrasonic dispersion device, a homogenizer, or the like. You may perform it, heating the containing liquid itself. In addition, when stirring a clay containing liquid under reduced pressure, a stirrer or a stirring blade may be used, and the container which rotates while revolving around the above-mentioned axis | shaft may be used.

Moreover, you may perform the above degassing operation after arrange | positioning a clay containing liquid on a support body. In this case, by arranging the clay-containing liquid on the support, a thin liquid film can be formed, and the gas component can be efficiently reduced as compared with the case of performing the degassing operation in the form of the clay-containing liquid in the state of the thick liquid film. .

When manufacturing a clay containing liquid in this invention, it is preferable that solid content concentration of a clay containing liquid is 0.5 mass% or more and 20 mass% or less. Since the time required for drying can be shortened by increasing solid content concentration, it is preferable to set it as 0.5 mass% or more. Moreover, the clay content liquid which the clay and the additive were disperse | distributed favorably is obtained by making solid content concentration into 20 mass% or less. In addition, since the viscosity of the clay-containing liquid is suppressed to a predetermined value or less and the thixotropy expression can be suppressed, gaseous components mixed in the clay-containing liquid are easily removed. The orientation and uniformity of the clay crystals in the clay film obtained as a result are improved, and the transparency, gas barrier properties, dimensional stability, etc. of the clay film are improved. In order to fully acquire these effects, it is more preferable that solid content concentration of a clay containing liquid is 1 mass% or more and 15 mass% or less, It is still more preferable that they are 1 mass% or more and 12 mass% or less.

In the present invention, after the gas component contained in the clay-containing liquid is agitated or reduced under reduced pressure, the paste-like clay-containing liquid in which the solvent is reduced by heating and the solid content concentration is higher may be used. In this case, it is also possible to raise solid content concentration of a clay containing liquid more than the preferable range mentioned above. Since drying time can be shortened while removing the gas component contained in a clay containing liquid by this, the effect that the mass productivity of a clay film can be improved is acquired.

Moreover, since it is possible to reduce fluidity by increasing viscosity and expressing thixotropy remarkably in some cases, the limitation of the support body mentioned above can be removed. That is, since the paste-like clay-containing liquid has low fluidity, it is not necessary to use a support having a structure that prevents outflow such as a partitioned container because the clay-containing liquid applied to the support does not flow out. Moreover, there exists an advantage that a paste-like clay containing liquid can also be apply | coated also to a slope. Moreover, even if it adds a thickener etc. to a clay containing liquid and makes it into a paste form, the said effect can be exhibited.

As a method of reducing the solvent in a clay containing liquid, although the heat evaporation method is preferable, it does not specifically limit but well-known solid-liquid separation techniques, such as centrifugation, filtration, and compression, can be used. The concentration step of increasing the solid content concentration may be performed under reduced pressure, and in particular, when the thickness of the clay-containing liquid is reduced and the flow is generated in the clay-containing liquid by stirring or the like, the amount of evaporation of the solvent is increased and the concentration can be concentrated in a short time. It is so effective. In addition, when the concentration is carried out under reduced pressure, deaeration proceeds simultaneously with concentration, which is preferable. However, if the clay-containing liquid is concentrated, it is difficult to remove the gaseous components remaining in the clay-containing liquid as described above. Therefore, it is important to concentrate after reducing the gaseous components contained in the clay-containing liquid sufficiently. . In addition, in the case where concentration and degassing are performed at the same time, it is important that degassing must be completed before concentration proceeds.

The clay-containing liquid thus obtained is applied to the surface of the support to a constant thickness, and then the solvent is slowly removed to form a clay film. Although the method of removing a solvent is not specifically limited, For example, centrifugation, filtration, vacuum drying, freeze vacuum drying, leaving under inert gas atmosphere, and heat evaporation method are preferable. Alternatively, a plurality of these methods may be combined.

When using the heat evaporation method among these methods, for example, a flat tray may be used as a support body, and a clay containing liquid may be apply | coated to this. Although the material of a support body is not specifically limited, It is necessary to be able to withstand the temperature at the time of heating. For example, a film, a board | substrate, glass, or a silicon wafer which consist of resin, such as polyethylene terephthalate (PET) and polypropylene, is mentioned. Moreover, the board | substrate which consists of metals, such as brass, copper, stainless steel, and aluminum, is also mentioned. It is generally preferable that the support has a higher thermal conductivity. In addition, when the applied clay-containing liquid does not flow out because the viscosity of the clay-containing liquid is high or the thixotropy is strong, it is not necessary to have a structure that prevents the leakage of the clay-containing liquid such as a tray. It is also possible to use a flat support.

In the process of solidifying and drying the clay-containing liquid with evaporation of the solvent, volume shrinkage is generated, and the stress caused by the volumetric shrinkage acts on the clay film obtained. Therefore, when the strength of the clay membrane cannot withstand this stress, the clay membrane may crack during the drying process, and in this case, it is difficult to produce a large-area clay membrane, and thus the use that can be applied is limited. There is a problem.

In such a case, it is preferable to use a support that is flexible and easily deformed in order to absorb the stress due to the volume shrinkage. By doing so, the clay membrane itself can be deformed together with the support during drying, or it can be dried while actively deforming the support in a shape that relieves the stress caused by volumetric shrinkage, so that the stress remaining inside the clay film can be reduced. It can alleviate the occurrence of cracking of the clay membrane.

The support is not particularly limited as long as it is flexible and easy to deform, but considering the effect of exfoliation of the clay film after drying, continuous production of the clay film in the form of a roll, and impact on the production cost of the clay film, inexpensive PET and the like Resin film is preferable.

It is preferable that at least a portion of the surface of the support in contact with the clay film is subjected to an easy peeling treatment or a water repellent treatment so that the clay film is easily peeled from the support. Or it is preferable to comprise a support body with polypropylene, polytetrafluoroethylene, etc. with strong water repellency. Examples of easy peeling treatment include ultraviolet irradiation treatment, electron beam irradiation treatment, ion beam irradiation treatment, corona discharge treatment, plasma treatment (e.g., remote plasma treatment, frame plasma treatment), and physical treatment (e.g., small contact area). Mechanical processing of the surface to be carried). Moreover, the process of apply | coating resin which lowers adhesiveness like silicone resin, and the process of apply | coating the peeling | distributing agent which reduces adhesiveness by changing a softness, a Young's modulus, or foaming by physical stimulation, such as light and heat, are mentioned. have. Alternatively, a plurality of these treatments may be combined.

In addition, although the same effect is often acquired by the above-mentioned easy peeling process as water-repellent processing, the method of coating a fluororesin and titania is mentioned as a preferable example.

It is preferable that the surface of the support is as smooth as possible. When it is not smooth, since the roughness of the surface of a support body is transferred to the surface of a clay film, the surface smoothness of a clay film will fall. In addition, in the transparent film, light is diffusely reflected to cause a haze to increase.

In the clay film made of hydrophilic clay, the stress generated in the clay film due to drying shrinkage is large immediately after drying, but the internal stress is often reduced when left for a while after drying. For example, most of the transparent film made of hydrophilic clay is curled by internal stress immediately after drying, but when left for about 10 minutes, the internal stress is opened to form a flat film. Therefore, the stress generated until the internal stress is reduced is derived by deforming the support, and after the internal stress is released, the clay film is peeled off from the support, thereby making it possible to produce a clay film without cracks or curls due to less internal stress. It is considered that the reason why the internal stress is reduced when left for a while after drying is that the flexibility is improved by absorption of moisture in the air. Therefore, keeping the clay film immediately after drying in an environment where humidity is controlled is effective in removing the internal stress of the clay film made of hydrophilic clay.

As described above, by using the deformable support, damage to the clay film due to stress due to volume shrinkage during clay film production can be suppressed. This makes it possible to produce a large area clay film with a high yield, and is therefore preferable for applications requiring a large area film such as a display. In addition, according to the present invention, in the case of continuous production by a roll using a support made of a film wound in a roll shape, it is easy to obtain a continuous clay film, so that a long clay film (for example, a clay tape) It is easy to manufacture.

When the solvent of the clay-containing liquid is removed by a heat evaporation method, a forced blowing oven or the like may be used. And a clay film is obtained when it is dried for 10 minutes or more and 7 hours or less under the temperature conditions of 30 degreeC or more and 120 degrees C or less. As for temperature conditions, 30 degreeC or more and 90 degrees C or less are more preferable, and 50 degreeC or more and 70 degrees C or less are more preferable. Moreover, 20 minutes or more and 3 hours or less are more preferable, and, as for drying time, 20 minutes or more and 2 hours or less are more preferable.

However, the optimum drying time varies depending on the film thickness of the clay film, the solid content concentration of the clay-containing liquid, the kind of the solvent used, and the like. Since water has a large specific heat and takes time to dry, an organic solvent is preferable as a solvent, and especially a solvent with a relatively low boiling point is preferable. And the combination which uses an organic solvent as a solvent and uses hydrophobic clay as a clay is preferable for shortening drying time. In addition, if the boiling point of the solvent is too low, the solvent is volatilized while adjusting the clay-containing liquid, and the solid content concentration is increased, and the risk of ignition explosion and the like is also increased. It is preferable to select a kind suitably.

By the manufacturing method of the clay film of this invention, the clay film which has the mechanical strength which can be used as a self-supporting film, and whose coefficient of linear expansion is small can be manufactured. In addition, in the case of using clay without coloring such as synthetic clay, a clay film having flat spectral characteristics, no coloring, and in which the variation in transmittance and haze cannot be visually confirmed over a wide range can be produced. By the way, in the conventional clay film, when left to stand in the air, the unevenness of the surface may increase with time. In particular, this phenomenon was remarkable when hydrophilic synthetic saponite or synthetic hectorite was used as clay, polyacrylate was used as an additive, and water was used as a solvent of the clay-containing liquid. The unevenness of the surface of the clay film is not only a big problem when applying another film to the surface of the clay film or forming an electronic device, but also the haze is increased due to the increase of the unevenness, and the clay film is clouded and the transparency decreases. It was an important task to solve.

This problem is solved by disposing a liquid which dissolves or disperses a liquid or an additive that swells clay on the surface of a clay film (hereinafter, also referred to as a primary dry film) obtained by drying the clay-containing liquid described above, and redrying. This can be solved. Moreover, even if such a problem does not arise, since the surface of a clay film can be smoothed by this method, it is also possible to reduce haze.

The method of disposing the liquid (liquid swelling clay or liquid dissolving or dispersing an additive) on the surface of the primary dry film obtained by drying the clay-containing liquid is not particularly limited, but for example, the primary dry film is It may be a method of immersion in the inside, or may be a method of spraying the liquid on the surface of the primary dry film like a spray. Alternatively, a method may be employed in which the primary dry film is placed in a high concentration vapor atmosphere of the liquid.

At this time, when the time that the primary dry film is in contact with the liquid is too long, part or all of the primary dry film may be redispersed in the liquid, or the primary dry film may absorb the liquid and swell excessively. have. Therefore, it is preferable that the time for which the primary dry film and the liquid are in contact is relatively short, and even if it is long from several seconds, it is preferably within a few minutes.

Further, when the liquid is disposed so as to wash the surface of the primary dry film by spraying the liquid on the surface of the primary dry film or by immersing the primary dry film in the flowing liquid, the film is smoothed and over time. It is often effective for suppressing the increase of haze. When the liquid is disposed on the surface of the primary dry film, the liquid may flow down while the primary dry film is inclined from the horizontal state so that the liquid does not stay on the surface of the primary dry film for a long time.

In addition, when arranging the liquid while keeping the primary dry film inclined from the horizontal state, it is preferable to dispose the liquid by loading the primary dry film on a mesh-like wire or the like used for papermaking. By doing so, since the excess liquid easily flows down from the surface of the primary dry film, part or all of the primary dry film can be suppressed from being redispersed or excessively swollen in the liquid.

The kind of the liquid is not particularly limited as long as it swells the clay or dissolves or disperses the additive, and may be appropriately selected depending on the kind of the clay and the additive. In particular, water is preferable as long as it is a clay film having a hydrophilic clay swelling in water or an additive dissolved in water.

Moreover, when the said whole film | membrane easily absorbs the liquid and changes to a gel form by arrange | positioning the said liquid on the surface of a primary dry film, the volume of a primary dry film increases with gelatinization, As a result, it has a wrinkle etc. Sometimes chips are produced. In such a case, the clay film may be stretched to spread the wrinkles to flatten the clay film, thereby obtaining a clay film having a smoother surface after drying. As a method of extending | stretching a clay film | membrane, the method of sticking a roller etc. to a clay film | membrane, and the method similar to biaxial stretching which pulls out a clay film | membrane is mentioned. The stretching of the clay film may be performed on a member having a smooth surface, on a mesh-like wire used for papermaking, or in a state in which it is not in contact with a support such as a smooth member.

After the primary drying, an additive is deposited on the surface of the clay film, and if the precipitated additive causes haze increase, the liquid is disposed on the surface of the primary dry film as described above. Since it is removed by the present invention, the effect of the present invention is exhibited.

In addition, in the primary dry film which arrange | positioned the said liquid as mentioned above, any one of a clay or an additive absorbs the said liquid, and the whole 1st dry film or the surface vicinity of the primary dry film which at least the said liquid contact | connects. The part swells. In such a state, the surface of the primary dry film is swollen and the surface area becomes large, so that the smoothness is not only improved, but the surface of the primary dry film is gelled, softened, and easily deformed by external force, so that the surface is smooth. Temporary contact of the surface of the softened primary dry film to the smoothing member deforms the surface of the primary dry film to follow the surface of the smoothing member, thereby smoothing the surface of the primary dry film, thereby improving the smoothness of the surface of the clay film obtained. Can be. For example, the clay film | membrane of which the surface was smoothed can be obtained by arrange | positioning the primary dry film | membrane which arrange | positioned the said liquid on the glass substrate or resin film with a smooth surface. Moreover, both surfaces of a clay film can also be smoothed by arrange | positioning the same glass substrate and resin film from that, and sandwiching a clay film with a smoothing member.

The smoothing member used for smoothing is not particularly limited as long as the surface is smooth, and a glass substrate, a silicon substrate, a resin substrate such as a polyethylene terephthalate (PET) film, or the like can be used. In addition, the surface of these smooth members may be subjected to the same ease of peeling treatment or water repellent treatment as applied to the support used in the preparation of the above-described primary dry film so as to easily peel off the clay film after smoothing.

In addition, when smoothing by bringing the primary dry film into contact with the smoothing member, an external force may be actively applied. For example, you may arrange | position a primary dry film after arrange | positioning the said liquid on a smooth resin film, and smooth it by rolling a roller with a smooth surface on it, apply an external force by press etc., and make a primary dry film adhere to a smooth member, You may smooth. At this time, the roller or the press device may be directly in contact with the primary dry film, and in the case where it is desired to prevent the primary dry film from adhering to the roller or the press device, a smooth resin film or the like that has undergone easy peeling treatment or the like as necessary. An external force may be applied through the.

The clay film which exhibits the effect of this invention mentioned above can be obtained by redrying the primary dry film | membrane which arrange | positioned the said liquid. Drying can be performed on any member or in a state not in contact with the member, but in order to finally obtain a clay film having a smooth surface, the surface used for smoothing the surface of the clay film is preferably performed on the smooth member. . Although the method of redrying is not specifically limited, For example, centrifugation, filtration, vacuum drying, freeze vacuum drying, leaving under inert gas atmosphere, and heat evaporation method are preferable. Alternatively, a plurality of these methods may be combined. Alternatively, it may be left alone in the air. At this time, in order to prevent foreign matters from adhering to the surface of the clay film and lowering the smoothness of the surface, it is preferable to re-dry in the clean oven or the clean room as few foreign substances as possible in the dry atmosphere.

Since the volumetric contraction occurs in the clay membrane during redrying, the stress due to the volumetric contraction acts on the clay membrane. In particular, when the entire membrane is swollen, the stress due to the volume shrinkage acts strongly. Therefore, when the strength of the clay film cannot withstand this stress in the case of redrying on the smoothing member, the clay film may crack in the drying process as in the case of producing the primary dry film. In order to avoid this, it is preferable that the smoothing member is flexible and the clay film is peeled from the smoothing member after redrying in a state in which the smoothing member is deformable. As the smoothing member having flexibility, a resin film is preferable.

According to the clay film production method of the present invention, a layer of clay crystals are highly oriented and laminated, and additives are intercalated between clay layers on average, excellent in uniformity, and low in defects due to mixed gas. A film can be made. The resulting clay film has a mechanical strength that can be used as a self-supporting film due to a dense laminated structure, and has a small coefficient of linear expansion. And when the clay without coloring, such as synthetic clay, is used, the clay film | membrane which is a flat spectral characteristic, there is no coloring, and a transmission and a haze cannot visually confirm over a wide range can be produced.

Although it is difficult to define the mechanical strength that can be used as the freestanding film, the tensile strength of the clay film is preferably 10 MPa or more, more preferably 15 MPa or more, still more preferably 20 MPa or more, and most preferably 25 MPa or more. If it is 10 MPa or more, it can be said that it has the intensity | strength which can be handled by hand, and if it is 25 MPa or more, it can be said that it has sufficient strength.

In the clay film obtained by the production method of the present invention, since the gas component contained in the clay-containing liquid is sufficiently removed, there are very few internal bubbles (voids) and the like. Therefore, although it depends also on the heat resistance of an additive, even if it observes the surface of a film in detail after heating to 300 degreeC rapidly (for example, at the temperature rising rate of 15 degreeC or more per minute) for 1 hour, and confirming the swelling on the surface, it is confirmed It is a clay film having excellent thermal stability that can be used under high temperature conditions of not less than 300 ° C.

Furthermore, in the transparent clay film, it has high transparency over the whole visible range, small haze, no coloring, and little in-plane variation of transparency. The removal of the gaseous components contained in the clay-containing liquid greatly influences the reduction of the haze. In addition, reducing the haze is a very important problem when applied to optical applications such as displays.

In the present invention, even when the clay film is thick (for example, thicker than 15 µm) by introducing a step of reducing gaseous components in the clay-containing liquid, the haze immediately after film formation can be made 5% or less. have. The haze is preferably 3% or less, more preferably 2% or less, still more preferably less than 1%. In addition, the change over time of the haze in an environment of 24 ° C., 1 atmosphere, and humidity of 45% can be made 2% or less. 1% or less is preferable and, as for the change with time of haze, 0.5% or less is more preferable. Moreover, it is possible to manufacture the thing with a total light transmittance of 85% or more, and the light transmittance of parallel light in the wavelength range of 400 nm or more and 800 nm or less by an ultraviolet visible spectroscope being 85% or more and 95% or less.

If the haze is more than 5%, there is a concern that the transparency is low and a desired optical characteristic cannot be obtained. In addition, the haze of glass substrates and optical film materials, such as a smooth surface and low haze, is generally about 0.5%, especially about 0.2% even if it is transparent, and the clay film obtained when these are used as a support or a smoothing member has Since unevenness is generally prescribed | regulated by these bases and the smoothing member, the haze of the obtained clay film is also made into a lower limit about 0.5% from 0.5% of good. In addition, if the change in haze over time is 2%, the transparency of the clay film decreases with time, which may cause a problem that the desired optical properties cannot be obtained.

In addition, the upper limit of the light transmittance is determined by the refractive index of the film. In general, since the refractive index of clay is often about 1.5, the light transmittance of parallel light of the clay film produced by the clay film production method of the present invention is considered to be about 95% even if an additive having a low refractive index is added. . Of course, if the surface of the clay film is laminated with a low refractive index antireflection film, a multilayer antireflection film using optical interference, or a film subjected to antiglare treatment or the like, the transmittance can be further improved.

According to the method for producing a clay film of the present invention, the average of 40 to 250 ° C. is due to the effect that the proportion of the additive is small, the layers of the viscosity crystals are highly oriented and laminated, and the additive is intercalated on average between the layers. It is possible to obtain a clay film having a linear expansion coefficient of 20 ppm or less as an absolute value. The linear expansion coefficient is preferably 15 ppm or less, more preferably 10 ppm or less, still more preferably 7 ppm or less, particularly preferably 5 ppm or less, and most preferably 3 ppm or less.

 Such a small coefficient of linear expansion may be unreachable in conventional nanocomposite bodies in which resins are mainly used even if they contain films made of conventional resins or clays, and the layers of clay crystals are dense and highly aligned. It is a very small value, especially for transparent films. Since most electronic devices are made of an inorganic material having a small coefficient of linear expansion, etc., it can be said that the clay film of the present invention has a very suitable characteristic as a substrate on which such electronic devices are mounted. Moreover, when such a clay film is used for packing etc., since the surface unevenness | corrugation is small, the effect that a leak of gas etc. can be suppressed more is acquired.

After producing the clay film, the clay and the additives are uniformly dispersed, and sufficient removal of the mixed gas is performed. As a result, as a method of confirming whether or not a layer of clay crystal is highly oriented and a laminated clay film is obtained, The analysis of the X-ray diffraction spectrum by a diffraction apparatus and the direct observation of the lamination state by a transmission electron microscope (TEM) are effective. Background Art Conventionally, research and evaluation of the alignment lamination state of the clay film formed on a support such as a glass substrate, the dispersion or peeling state of the clay crystal in the nanocomposite body containing clay, and the like are widely conducted by X-ray diffraction measurement. It is done. In general, the intensity and position of the main peak (bottom reflection peak on the lowest 2θ side) occurring in the X-ray diffraction spectrum by the first order diffraction of the (001) plane of the clay crystal, and the X in the low 2θ region The lamination state (average spacing of layers) and the dispersion state of clay crystals can be known by rising of the background of the line diffraction spectrum.

The average interlayer distance in the clay film whose ratio of an additive is less than 30 mass% is 10 nm or less in conversion from the position of the said main peak in an X-ray diffraction spectrum. This average interlayer distance is preferably 7 nm or less, more preferably 5 nm or less, still more preferably 4 nm or less, particularly preferably 3.5 nm or less, and most preferably 2 nm or less. In addition, when the average interlayer distance is 1.5 nm or less, very high gas barrier properties that fall below the measurement limit of the existing measuring device can be expressed.

This preferred average interlayer distance is a smectite group having a thickness of one layer of clay crystal in the case of measurement using a wavelength of 1.54 GHz, which is a general copper Kα line, in terms of the top position (value of 2θ) of the first diffraction peak. In the clay film which consists of the clay of the clay and the clay of the synthetic mica group, it corresponds to the area of 0.8 or more and 9.0 or less in 2 (theta).

In addition, although the minimum value of the said average interlayer distance corresponds to that of the composition which consists only of clay, in the clay film of this invention, since the additive is intercalated on average between layers, an average interlayer distance is larger than that of the composition which consists only of clay. It is. As a method for confirming this, whether the peak top position of the main peak in the X-ray diffraction spectrum is shifted to the 2θ side lower than that of the composition composed of clay alone, or the peak width of the main peak is broadened to the low 2θ side. The goal is to be broadening. In addition, whether the average interlayer distance in a clay film exists in the said preferable range can also be confirmed by measuring the interlayer distance directly from the image obtained by photography by TEM.

Moreover, the clay film obtained by the manufacturing method of the clay film of this invention generally has high barrier property with respect to the inorganic gas of hydrogen, oxygen, and nitrogen. The gas barrier properties vary greatly depending on the type of clay and additives used, but when defined as transmittance, they are 1/2 or less of the membrane composed of only the additives used. 1/10 or less of the film | membrane which consists only of the used additive is preferable, 1/100 or less is more preferable, and 1/1000 or less is further more preferable. Depending on the composition of the clay film, gas barrier properties below the limit of measurement of the general-purpose gas permeability measuring device (for example, Mocon's device) in the present situation may be exhibited.

And since the clay film of this invention has the intensity | strength which can be used as a self-supporting film, it can be used for various uses. For example, it is possible to form an active matrix driving circuit directly on the clay film at high temperature by utilizing heat resistance, gas barrier property, flexibility, low linear expansion, and the like as a backplane of flexible electronic paper. This eliminates the need for a conventional method such as transferring a resin film after forming a drive circuit on a heat resistant glass substrate or the like, thus reducing the manufacturing process of the electronic paper, which is advantageous in terms of cost. Transparency is generally unnecessary if it is the backplane of an electronic paper. Moreover, if a clay film is transparent, it can be used as a board | substrate and a gas barrier film by the front plane side which are the visual side of an electronic paper. Moreover, although the kind of electronic paper which can apply the clay film of this invention is not specifically limited, For example, the electrophoretic drive type and the electronic paper of the electron powder fluid type | mold are mentioned.

In addition, the clay film can be used extensively as a flexible substrate of an electric circuit, taking advantage of insulating characteristics. Even when used as a substrate for an electric circuit, the unevenness or linear expansion coefficient of the substrate surface is more preferably smaller, and the clay film of the present invention is preferable for the purpose of preventing disconnection of wiring. In particular, in a flexible printed circuit board in which the conductive portion on the substrate is formed by coating or printing conductive ink, the conductive ink can be baked at a higher temperature by utilizing the heat resistance of the clay film and a low coefficient of linear expansion. It is possible to lower the resistivity of the conductor portion. As a preferable use of such a flexible board | substrate and a flexible printed circuit board, the board | substrate of an RFID tag, a copper clad laminated board, etc. are mentioned. Moreover, if it is a transparent clay film, it is applicable also to the device which needs to pass light like a solar cell.

In addition, organic semiconductors typified by pentacene and thiophenes are generally susceptible to deterioration due to oxygen and moisture, and amorphous inorganic semiconductors are also less susceptible to oxygen and moisture than organic semiconductors. Therefore, in the device using these, it is necessary to sufficiently prevent the invasion of oxygen or water vapor. Since the clay film of the present invention has a high gas barrier property, it is also suitable as a substrate for an electronic device having an organic semiconductor or an amorphous inorganic semiconductor sensitive to deterioration due to oxygen or the like, or as a gas barrier film for protecting an organic semiconductor or an amorphous inorganic semiconductor. Do. In addition, since the clay film maintains flexibility even at high temperatures, it is possible to make the electronic device flexible.

In addition, when applying the clay film of this invention with respect to the electronic device which has the above-mentioned electronic paper, a flexible substrate, a flexible printed circuit board, an organic semiconductor, or an amorphous inorganic semiconductor, you may apply a clay film as it is, and if necessary, another function to a clay film And a film (for example, a vapor barrier film mainly composed of an inorganic material, a reinforcing material composed of a resin material, etc., a protective layer for preventing scratches, and a smoothing layer for smoothing the surface) may be used.

Furthermore, after imparting to the clay film a film having a function different from that of the clay, such as a reinforcing material made of the above water vapor barrier film, a resin material, a protective layer for preventing wounds, and a smoothing layer for smoothing the surface, the clay film is applied to the clay film surface. A liquid may be arrange | positioned and swelled and it may be re-dried to improve the smoothness of a clay membrane part. For example, after sticking a film made of a resin or the like to one surface of the clay film, the film made of clay and the resin film may be immersed in a liquid or swelled by spraying a liquid on the clay surface to re-dry it. Of course, in a composite film in which a large number of films other than clay having a function separate from the clay film are laminated, improvement by the above method is possible if at least the outermost layer of one surface of the composite film is a clay film.

Below, the clay film of this invention and its manufacturing method are demonstrated in detail.

The kind of clay used in this invention is not specifically limited, It may be natural clay or synthetic clay. For example, mica, vermiculite, montmorillonite, iron montmorillonite, Weidelite, saponite, hectorite, stevensite, nontronite, margotite, hydrotalcite, kaolinite, and halosite are preferred. In particular, synthetic clay is preferable in the transparent clay film. As synthetic clay, synthetic saponite, synthetic hectorite, synthetic stevensite, synthetic mica, synthetic hydrotalcite, synthetic kaolinite and the like are preferable, but clay belonging to the smectite group is more preferable in terms of dispersibility and the like. From the viewpoint of gas barrier properties, natural montmorillonite or clay belonging to the mica group having a large aspect ratio of the layer of clay crystals is preferable. In addition, from the viewpoint of gas barrier properties, high aspect ratio synthetic smectite group clays, synthetic mica and hydrotalcite are also preferable.

Moreover, you may use hydrophobic clay which performed the process using the salt which has organic ions, such as an ammonium salt, a phosphonium salt, an imidazolium salt, carboxylic acid, etc., and improved the dispersibility to an organic solvent. This treatment is a treatment for exchanging inorganic ions included in hydrophilic clay with organic ions. Further, the treatment of converting the hydroxyl group of the octahedral sheet, which most of the clay minerals have as a component of the layer structure, to another hydrophobic substituent by chemical reaction (for example, by dehydrating bonds with any silane coupling agent) Hydrophobic clay which further improves water resistance or controls dispersibility in an organic solvent by treating with another organic group). In particular, the organic smectite obtained by hydrophobizing clay belonging to the smectite group is preferable from the viewpoint of ease of performing the above treatment and dispersibility.

Among the salts having organic ions, ammonium salts having alkyl groups, benzyl groups, polyoxyethylene groups, oxyethylene groups, oxypropylene groups, and the like, and quaternary ammonium salts such as dimethyl distearyl ammonium salt and trimethyl stearyl ammonium salt Can be. Moreover, it is known that phosphonium salt, imidazolium salt, etc. are high in heat resistance, and are hard to show decomposition | disassembly, coloring, etc. even at high temperature. Therefore, by using hydrophobic clay treated with phosphonium salt, imidazolium salt or the like, a clay film having excellent heat resistance can be obtained. Since hydrophobic clay has low affinity with water, the clay film obtained also has low affinity with water, and as a result, it becomes excellent in water resistance.

The clay in the present invention includes both of these hydrophilic clays and hydrophobic clays. In hydrophobic clay, organic ions bound to the surface of the tetrahedral sheet or octahedral sheet described above are defined as part of the clay. The presence of organic ions in hydrophobic clay slightly increases the interlayer distance of the clay crystals, leading to the disadvantage of deterioration of gas barrier properties, but is strongly bound to the surface of the tetrahedral sheet or the octahedral sheet. In general, the influence on the dimensional stability and the like is preferable because it has a merit of small water resistance and water resistance that does not exist in hydrophilic clay. In addition, hydrophobic clay is generally obtained by exchanging inorganic ions such as alkali metals existing between layers of hydrophilic clay with organic ions. Therefore, when hydrophobic clay sufficiently ion-exchanged is used, it is also possible in principle to obtain a clay film containing almost no alkali metal. Therefore, it is considered to be suitable for the electronic device use which is reluctant to alkali metal.

Although the kind of additive used in this invention is not specifically limited, The main role of an additive is to improve the flexibility and strength of a clay film, and to stress of the volume shrinkage at the time of removing the solvent of a clay containing liquid. In order to relax (to ensure surface smoothness and uniformity of the interior of the clay film), it is generally preferable that the additive itself has flexibility, elasticity or fluidity. The form of the additive itself need not be solid, and may be a liquid or a sol or gel as long as it is dissolved or dispersed uniformly in a solvent. In the case of producing a transparent clay film, the additive is also preferably transparent or less colored.

As such a substance, the polymer which mainly contains carbon and silicon in a main chain is especially preferable. Of course, it may be a monomer having a polymerizability which is polymerized with another monomer or polymer in the clay film and converted into a polymer. It may also contain organic ions which interact with clay.

Such additives are specifically shown. When the solvent for dissolving or dispersing the clay is water, the additive is also preferably hydrophilic and has high dispersibility or solubility in water. For example, epsilon caprolactam, dextrin, starch, cellulose resin, cellulose fiber, gelatin, agar, wheat flour, gluten, alkyd resin, polyurethane resin, epoxy resin, fluorine resin, acrylic resin, methacrylic resin, phenol resin, poly Amide resin, polyester resin, polyimide resin, polyvinyl resin, polyethylene glycol, polyacrylamide, polyethylene oxide, protein, deoxyribonucleic acid, ribonucleic acid, polyamine acid, polyhydric phenol, benzoic acid compound are preferable. Do. Alternatively, a water dispersion material such as latex or emulsion may be used. Moreover, since these are high in dispersibility or solubility in water, water resistance is generally low. Therefore, an additive may be insolubilized in water by adding a salt, another reactive monomer, a polymer, an oligomer, or the like. However, in the case of using a water dispersion type material such as latex or emulsion, it is also possible to improve the water resistance of the film by heat treatment after film formation or the like.

In addition, when hydrophobic clay such as organic smectite is used as the clay, and a solvent other than water is used as the solvent, or when a mixed solvent of water and another hydrophilic solvent is used, an additive having hydrophilicity and high dispersibility or solubility in water is used. There is no need to use it. In this case, if it is an additive with low dispersibility or solubility in water, the clay film obtained will also become hydrophobic, As a result, a clay film with high water resistance can be obtained.

Examples of such additives include styrene resins, acrylic resins, aromatic polycarbonate resins, aliphatic polycarbonate resins, aromatic polyester resins, aliphatic polyester resins, aliphatic polyolefin resins, cyclic olefin resins, and polyamide resins. Thermoplastic resins such as resins, polyphenylene ether resins, thermoplastic polyimide resins, polyacetal resins, polysulfone resins, and amorphous fluorine resins.

In addition, epoxy resin, thermosetting modified polyphenylene ether resin, thermosetting polyimide resin, urea resin, allyl resin, silicon resin, benzoxazine resin, phenol resin, unsaturated polyester resin, bismaleimide triazine resin, alkyd Thermosetting resins, such as resin, furan resin, melamine resin, a polyurethane resin, and aniline resin, can also be used.

In addition, a photocurable resin can also be used, for example, the epoxy resin containing a latent photocationic polymerization initiator, etc. are mentioned. Moreover, when hardening the said photocurable resin, you may add heat simultaneously with light irradiation. In addition, in this invention, although you may use a hardening | curing agent, a hardening catalyst, etc. in combination with a thermosetting resin and a photocurable resin, these are not specifically limited as long as it is generally used for hardening of a thermosetting resin and a photocurable resin. Specific examples of the curing agent include polyfunctional amines, polyamides, acid anhydrides, and phenol resins. Examples of the curing catalyst include imidazole and the like. These hardening | curing agents and hardening catalysts can be used individually or in mixture of 2 or more types. In addition, the resin mentioned above may be used independently and may use 2 or more types together.

The above is mainly a resin in which the main chain is made of carbon atoms, but the main chain does not need to be made of carbon atoms, for example, may be a resin in which the main chain is made of silicon atoms, or a resin in which the main chain is made mainly of silicon and oxygen (for example, silicon). .

Further, salts containing organic ions such as ammonium salts, phosphonium salts, imidazolium salts and the like used in the treatment of the clays described above may be used as additives. Such salts are preferred as additives because they have a high bonding strength with clay. In particular, an additive containing two or more organic salt sites in one molecule crosslinks the layers of the clay crystals to improve the bonding strength between the layers of the clay crystals, thereby improving the water resistance and gas barrier properties of the clay film. As an additive containing two or more such organic salt moieties, for example, two or more units containing the organic salt moiety are a chain consisting of silicon atoms or a chain consisting of silicon atoms and oxygen atoms (e.g., polysilane, silicon, etc.). The molecule | numerator connected by) is mentioned. Moreover, the molecule | numerator which has the unit containing the said organic salt site | part, and the site | part which has polymerizability, such as a vinyl group and an epoxy group, in 1 molecule is mentioned.

In addition, an additive is not limited to what contributes to the strength improvement of a clay film, For example, when it wants to provide flame retardancy, you may add an inorganic flame retardant, such as antimony trioxide, and when you want to provide plasticity, dimethyl phthalate and You may add the same plasticizer. However, when manufacturing a transparent clay film, it is preferable that said additive also has little transparency or coloring.

In addition, although the kind of solvent used in this invention is not specifically limited, Water and an organic solvent can be used. In addition, water obtained by dissolving a small amount of organic substances such as acetamide, N, N-dimethylformamide, ethanol and methanol, salts and the like can also be used. The purpose of adding organic substances, salts and the like is to change the dispersibility of the clay in the clay-containing liquid, to change the viscosity of the clay-containing liquid, to change the ease of drying the clay membrane, and to improve the uniformity of the clay membrane. And so on.

In order to fully disperse the hydrophobic clay, addition of a high polar solvent such as methanol is effective. In particular, when the main solvent is a solvent having a small polarity such as toluene, it is preferable to add a small amount of a high polar solvent such as methanol to the main solvent. 0.1 mass% or more and 20 mass% or less of a main solvent are preferable, and, as for the addition amount of a high polar solvent like methanol, 0.5 mass% or more and 15 mass% or less are more preferable.

When a small amount of methanol is added to the dispersion of hydrophobic clay, methanol penetrates between the layers of the clay crystals of aggregated hydrophobic clay, and the space between the layers increases. If sufficient shearing force is applied, it can be dispersed to near the unit layer of the clay crystal. As a result, the dispersion of clay crystals is greatly promoted, and the aggregates of clay are virtually eliminated. Thus, most of the clays are peeled to near the unit layer, and a clay-containing liquid in which additives and clays are mixed very uniformly can be obtained. In addition, by producing a clay film with a clay-containing liquid in which methanol and the like are added to promote dispersion, an effect that the haze is significantly reduced is particularly achieved in the transparent clay film.

In addition, when using hydrophobic clay subjected to the above-mentioned treatment, aromatic hydrocarbons (for example, toluene, xylene), ethers (for example, ethyl ether, tetrahydrofuran), ketones (for example, acetone, methylethyl, etc.) as solvents Ketones), aliphatic hydrocarbons (e.g. n-octane), alcohols (e.g. methanol, ethanol, isopropanol), halogenated hydrocarbons (e.g. chloroform, dichloromethane, 1,2-dichloroethane), N, N- Dimethylformamide, N-methylpyrrolidone, dioctyl phthalate, dimethyl sulfoxide, methyl cellulsolve and the like can be used.

Since the kind of organic solvent in which hydrophobic clay can disperse | distribute largely depends on the kind of organic functional group on the surface of the clay crystal which expresses hydrophobicity, it is necessary to select an appropriate thing. In addition, it is necessary to carefully select the solubility and dispersibility of the additive to be finally mixed in the clay-containing liquid, and it is preferable to select an organic solvent that is good for both the dispersibility of the clay and the solubility and dispersibility of the additive. However, the solvent of the clay dispersion and the solvent of the additive-containing liquid need not necessarily be the same, and are not particularly limited as long as the clay and the additive are well maintained in a dispersed state when the mixed and obtained clay-containing liquid is obtained.

An Example is shown to the following and this invention is demonstrated to it further more concretely.

EXAMPLE 1

Synthetic saponite (Sumekuton SA manufactured by Kunimine Kogyo Co., Ltd.) was used as clay, and sodium polyacrylate (made by Wako Pure Chemical Industries, Ltd.) was used as an additive.

10.2 g of clay and 594 ml of pure water were placed together with a rotor in a plastic sealed container and shaken vigorously at 25 ° C. for 2 hours to obtain a uniform clay dispersion. In addition, 1.8 g of sodium polyacrylate and 594 ml of pure water were put together with a rotor in a plastic sealed container, and shaken vigorously at 25 ° C. for 2 hours, followed by further stirring for 7 minutes at a rotational speed of 10000 rpm using a homogenizer to obtain uniformity. An additive containing liquid was obtained. At this time, the additive-containing liquid generated heat, the temperature was raised to about 60 ° C., and the viscosity of the liquid was lowered.

Subsequently, the clay dispersion and the additive-containing liquid were placed together with a rotor in a plastic sealed container, and shaken vigorously at 25 ° C. for 2 hours, followed by further stirring for 20 minutes at a rotational speed of 10000 rpm using a homogenizer to contain uniform clay. A solution was obtained. At this time, the clay-containing liquid was exothermic, the temperature was raised to about 90 ° C., and the viscosity of the clay-containing liquid was lowered. And the clay containing liquid of about 90 degreeC was put into the vacuum degassing apparatus, and deaeration was carried out for 20 minutes under reduced pressure of 0.08 Mpa or less.

Next, this clay-containing liquid was applied to the flat portion of the surface of the tray made of polypropylene. A clay-containing liquid film of uniform thickness was formed by using a spatula made of stainless steel for application of the clay-containing liquid and using a spacer as a guide. This tray was put into a forced-air oven, and it heated and dried for about 6 hours on 60 degreeC temperature conditions. The resulting clay film was peeled off from the tray to obtain a uniform clay film having a thickness of about 22 μm. The obtained clay film had the mechanical strength available as a freestanding film. Moreover, transparency was high and was excellent in flexibility.

In order to confirm the flexibility of the clay film, the curvature was bent into a cylindrical shape having a radius of 6 mm, but no cracks or the like occurred and no defects occurred. In addition, in order to confirm the transparency of a clay film, the range of 312 nm-800 nm as a result of measuring the transmittance | permeability in the wavelength range of 200 nm-800 nm with the ultraviolet visible spectrophotometer "UV-3101PC" made by Shimadzu Corporation Has a transmittance of 85% or more (see FIG. 1), and no coloring was confirmed. In addition, the total light transmittance of the clay film measured by the turbidimeter "NDH2000" made from Nippon Denshoku Kogyo Co., Ltd. was 91.7%, and haze (dise) was 2.3%.

Subsequently, in order to confirm the dimensional stability of this clay film, the linear expansion coefficient was measured by "TMA / SS220" made by S.I. Nanotechnology. The sample width was 3 mm and the load was 2 g. After heating up to 233 degreeC at the temperature increase rate of 5 degree-C / min, it cooled to 31 degreeC, and immediately heated up to 300 degreeC at the temperature increase rate of 5 degree-C / min, and measured the linear expansion coefficient. As a result, the average linear expansion coefficient in the temperature range of 40 degreeC-250 degreeC was 5.4 ppm / degreeC, and the value of the linear expansion coefficient was substantially constant in the said temperature range.

This clay film was analyzed by X-ray diffraction using Rigaku's X-ray diffractometer "RINT-2500" to confirm whether the layers of clay crystals were highly oriented and densely stacked. did. The X-ray wavelength used is 1.54056 GHz of Cu / Kα. In the obtained X-ray diffraction spectrum (see Fig. 2), a clear main peak was confirmed at a position of 1.44 (in terms of interlayer distance of 1.19 nm) at 2θ, and a layer of clay crystals in the clay film was highly laminated. It can be seen that it is closely aligned.

In addition, electron micrographs of the cross sections of clay membranes were taken using a TEM `` HF-2000 '' manufactured by Hitachi Seisakusho Co., Ltd. It turned out that it is a uniform structure (refer FIG. 3).

In addition, in order to confirm the gas barrier property of this clay film, the permeation coefficient of oxygen was measured with the gas permeation amount measuring apparatus "Gasperm-100" made by Nippon Bunko Corporation. As a result, it was confirmed that the oxygen transmission coefficient at room temperature was less than 3.2 × 10 ⁻¹¹ cm 2 s ⁻¹ cmHg ⁻¹ , indicating high gas barrier performance.

EXAMPLE 2

When manufacturing a clay film similarly to Example 1, three clay films from which the film thickness differs were produced by changing the quantity of the clay containing liquid which flows into the polypropylene tray. The film thickness of the obtained clay film was 13 micrometers, 19 micrometers, and 24 micrometers, respectively.

As a result of measuring the transmittance in the same manner as in Example 1, the film thickness of 13 μm was in the range of 278 nm to 800 nm, the film thickness of 19 μm was in the range of 344 nm to 800 nm, and the film thickness of 24 μm was in the range of 326 nm to 800 nm. , All had a transmittance of 85% or more, and coloring was not confirmed. In addition, the shape of the ultraviolet visible absorption spectrum was almost the same as the clay film of Example 1.

Moreover, as a result of measuring total light transmittance similarly to Example 1, it was 91.7% for the film thickness of 13 micrometers, 90.9% for the film thickness of 19 micrometers, and 91.6% for the film thickness of 24 micrometers. Moreover, as a result of measuring haze (doughness) similarly to Example 1, it was 1.9% for the film thickness of 13 micrometers, 3.4% for the film thickness of 19 micrometers, and 2.9% for the film thickness of 24 micrometers.

EXAMPLE 3

In the same manner as in Example 1, a degassed clay-containing liquid was obtained. After putting the smooth PET film (made by Osaka Laminator Co., Ltd.) of thickness 50micrometer in which the peeling facilitation process was performed to the surface in the brass tray of B4 size, and fixing the circumference of PET film with adhesive tape, this PET film The clay containing liquid was apply | coated to the surface on which the peeling easy process of the process was given, and it carried out similarly to Example 1, and obtained the uniform clay film of about 22 micrometers in thickness. The obtained clay film had the mechanical strength which can be used as a freestanding film. Moreover, transparency was high and was excellent in flexibility.

In order to confirm the flexibility of the clay membrane, the curvature was bent into a cylindrical shape having a radius of 6 mm, but no cracks or the like occurred and no defects occurred. In the same manner as in Example 1, the transmittance was measured, and the transmittance was 85% or more in the range of 264 nm to 800 nm, and coloring was not confirmed. In addition, the shape of the ultraviolet visible absorption spectrum was almost the same as that of the clay film of Example 1. In addition, it was 92.0% as a result of measuring the total light transmittance similarly to Example 1, and 1.6% as a result of measuring haze (lightness).

The clay film was heated at 300 DEG C for 1 hour in the air, and as a result of measuring the transmittance, it had a transmittance of 85% or more in the range of 385 nm to 800 nm, and coloring was not confirmed. The shape of the ultraviolet visible absorption spectrum was almost the same as before heating. Moreover, as a result, it was 91.1% as a result of measuring the total light transmittance, 1.9% as a result of measuring haze (paleness), and high heat resistance was confirmed.

[Comparative Example 1]

The clay dispersion and the additive-containing liquid prepared in the same manner as in Example 1 were placed in a sealed container made of plastic together with the rotor and shaken vigorously at 25 ° C. for 2 hours, followed by a homogenizer for 20 minutes at a rotational speed of 10000 rpm. It stirred and obtained the uniform clay containing liquid.

This clay-containing liquid was applied to the surface of a PET film in the same manner as in Example 3 without degassing to obtain a uniform clay film having a thickness of about 17 μm. The obtained clay film had the mechanical strength which can be used as a freestanding film. In the clay film, many bubbles which can be seen with the naked eye were confirmed on the surface, and the unevenness was felt clearly by touching with a finger. It was 91.8% as a result of measuring the total light transmittance similarly to Example 1, and 5.1% as a result of measuring haze (doughness).

[Comparative Example 2]

Synthetic saponite (Sumekuton SA manufactured by Kunimine Kogyo Co., Ltd.) was used as clay, and sodium polyacrylate (made by Wako Pure Chemical Industries, Ltd.) was used as an additive.

5.1 g of clay and 594 ml of pure water were put together with a rotor in a plastic sealed container and shaken vigorously at 25 ° C. for 2 hours to obtain a uniform clay dispersion. 0.9 g of sodium polyacrylate was added to the clay dispersion as it was, followed by vigorous shaking at 25 ° C. for 2 hours to obtain a clay-containing liquid. Using the clay-containing liquid thus obtained, the subsequent steps were carried out in the same manner as in Example 3 to obtain a uniform clay film having a thickness of about 17 μm.

The obtained clay film had the mechanical strength which can be used as a freestanding film. In order to confirm the flexibility of the clay membrane, the curvature was bent into a cylindrical shape having a radius of 6 mm, but no cracks or the like occurred and no defects occurred. In the same manner as in Example 1, when the transmittance was measured, there was no wavelength region having a transmittance of 85% or more (see FIG. 1). In addition, it was 91.8% when the total light transmittance was measured similarly to Example 1, and was 7.0% when the haze (paleness) was measured.

(Comparative Example 3)

In producing the clay film similarly to Comparative Example 2, two clay films having different film thicknesses were produced by changing the amount of the clay-containing liquid to be poured into the tray. The film thickness of the obtained clay film was 15 micrometers and 16 micrometers, respectively.

As a result of measuring the transmittance in the same manner as in Example 1, no clay film had a wavelength region having a transmittance of 85% or more. Moreover, as a result of measuring the total light transmittance similarly to Example 1, the thing of the film thickness of 15 micrometers was 92.0%, and the thing of the film thickness of 16 micrometers was 91.7%. Moreover, as a result of measuring haze (doughness) similarly to Example 1, the thing of the film thickness of 15 micrometers was 7.7%, and the thing of the film thickness of 16 micrometers was 6.5%.

Comparative Example 4

Synthetic saponite (Sumekuton SA manufactured by Kunimine Kogyo Co., Ltd.) was used as clay, and sodium polyacrylate (made by Wako Pure Chemical Industries, Ltd.) was used as an additive.

1.8 g of sodium polyacrylate and 594 ml of pure water were placed in a plastic sealed container together with a rotor and shaken vigorously at 25 ° C. for 2 hours to obtain an additive-containing liquid. 5.1 g of clay was added to this additive-containing liquid and shaken vigorously at 25 ° C. for 2 hours. However, clay was not sufficiently dispersed, and many large clay aggregates were confirmed, so that a clay-containing liquid suitable for the production of clay membranes could not be obtained.

(Comparative Example 5)

Synthetic saponite (Sumekuton SA manufactured by Kunimine Kogyo Co., Ltd.) was used as clay, and sodium polyacrylate (made by Wako Pure Chemical Industries, Ltd.) was used as an additive.

4.0 g of clay and 196 ml of pure water were put together with a rotor in a plastic sealed container and shaken vigorously at 22 ° C. for 2 hours to obtain a uniform clay dispersion. In addition, 2 g of sodium polyacrylate and 198 ml of pure water were put together with a rotor in a plastic sealed container, and shaken vigorously at 22 ° C. for 2 hours, followed by further stirring for 7 minutes at a rotational speed of 10000 rpm using a homogenizer to obtain a uniform additive. The containing liquid was obtained.

Subsequently, the clay dispersion and the additive-containing liquid were placed in a plastic sealed container together with the rotor. The ratio of clay dispersion and additive-containing liquid is 3 to 7 by mass. After vigorous shaking at 22 ° C. for 2 hours, a homogenizer was further used for 20 minutes at a rotation speed of 10000 rpm to obtain a uniform clay-containing liquid having a clay content of less than 50 mass%.

Using this clay-containing liquid without degassing, it carried out similarly to Example 3, and obtained the uniform clay membrane of about 20 micrometers in thickness. In order to confirm the flexibility of the clay membrane, the curvature was bent into a cylindrical shape having a radius of 6 mm, but no cracks or the like occurred and no defects occurred. In addition, it was 91.8% as a result of measuring the total light transmittance similarly to Example 1, and 6.3% as a result of measuring haze (lightness).

EXAMPLE 4

Synthetic saponite (Sumekuton SA manufactured by Kunimine Kogyo Co., Ltd.) was used as clay, and carboxymethylcellulose sodium (made by Aldrich Co., Ltd.) was used as an additive, respectively.

1.0 g of clay and 89 ml of pure water were put together with a rotor in a plastic sealed container and shaken vigorously at 25 ° C. for 2 hours to obtain a clay dispersion. Further, 0.18 g of sodium carboxymethyl cellulose and 30 ml of pure water were put together with a rotor in a plastic sealed container, and shaken vigorously at 25 ° C. for 2 hours, followed by further stirring for 10 minutes at a rotational speed of 10000 rpm using a homogenizer to add the additive. The containing liquid was obtained.

Subsequently, the clay dispersion and the additive-containing liquid were mixed and shaken vigorously for 2 hours, followed by further stirring for 10 minutes at a rotation speed of 10000 rpm using a homogenizer to obtain a clay-containing liquid having a solid content concentration of 1% by mass. Then, the clay-containing liquid was stirred for 5 minutes with a rotating-rotating type stirring degassing apparatus AR-100 (manufactured by Shinki Co., Ltd.) equipped with a container rotating around the shaft. Thereafter, the robot was degassed for 2 minutes in the degassing mode in which the rotating was stopped and the mixed air bubbles were removed by the centrifugal force of only the revolution motion. The obtained clay-containing liquid was placed in a plastic dispensing tray to form a thin liquid film having a thickness of about 5 mm or less, and vacuum degassed for 10 minutes under a reduced pressure of 0.08 MPa or less.

The same PET film as used in Example 3 was placed in a tray prepared by attaching a 1 mm thick Teflon (trademark) guide to a B6 brass plate, and containing 20.1 g of clay on the surface coated with the silicone resin of the PET film. The liquid (thickness 3mm) was apply | coated. And the liquid surface of the apply | coated clay containing liquid was smoothed with the glass rod.

The tray containing this clay containing liquid was put in oven, and it heated and dried about 60 hours on 60 degreeC temperature conditions. After drying, the obtained clay layer was peeled from the PET film to obtain a uniform transparent clay film having a thickness of about 14 μm.

In the same manner as in Example 1, the total light transmittance of the clay film was measured and found to be 91.3%, and the haze (paleness) was measured and found to be 3.5%.

[Example 5]

Natural montmorillonite (Kunipia F manufactured by Kunimine Kogyo Co., Ltd.) was used as clay, and sodium polyacrylate (made by Wako Pure Chemical Industries, Ltd.) was used as an additive.

27.4 g of clay and 658 ml of pure water were put together with a rotor in a plastic sealed container and shaken vigorously at 25 ° C. for 2 hours to obtain a uniform clay dispersion. In addition, 1.44 g of sodium polyacrylate and 142 ml of pure water were put together with a rotor in a plastic sealed container, and shaken vigorously at 25 ° C. for 2 hours, followed by further stirring for 7 minutes at a rotational speed of 10000 rpm using a homogenizer to obtain uniformity. An additive containing liquid was obtained. At this time, the additive-containing liquid was exothermic, the temperature was raised to about 60 ° C., and the viscosity of the liquid was lowered.

Subsequently, the clay dispersion and the additive-containing liquid were placed together with a rotor in a plastic sealed container, and shaken vigorously at 25 ° C. for 2 hours, followed by further stirring for 20 minutes at a rotational speed of 10000 rpm using a homogenizer to contain uniform clay. A solution was obtained. At this time, the clay-containing liquid was exothermic, the temperature was raised to about 90 ° C., and the viscosity of the clay-containing liquid was lowered. And the clay containing liquid of about 90 degreeC was immediately put into the vacuum degassing apparatus, and deaeration was carried out for 20 minutes under reduced pressure of 0.08 Mpa or less.

Next, this clay-containing liquid was applied to the flat portion of the surface of the brass tray. A clay-containing liquid film of uniform thickness was formed by using a spatula made of stainless steel for application of the clay-containing liquid and using a spacer as a guide. This tray was put into a forced-air oven, and it heated and dried for about 6 hours on 60 degreeC temperature conditions. The resulting clay film was peeled off from the tray to obtain a uniform clay film having a thickness of about 40 μm. Since the obtained clay film had sufficient mechanical strength, it could be used as a self-supporting film and was excellent in flexibility.

In order to confirm the flexibility of the clay membrane, the curvature was bent into a cylindrical shape having a radius of 6 mm, but no cracks or the like occurred and no defects occurred.

(Comparative Example 6)

Natural montmorillonite (Kunipia F manufactured by Kunimine Kogyo Co., Ltd.) was used as clay, and sodium polyacrylate (made by Wako Pure Chemical Industries, Ltd.) was used as an additive.

27.4 g of clay and 658 ml of pure water were put together with a rotor in a plastic sealed container and shaken vigorously at 25 ° C. for 2 hours to obtain a uniform clay dispersion. 1.44 g of sodium polyacrylate was added to the clay dispersion and shaken vigorously at 25 ° C. for 2 hours, but a large number of large aggregates were generated, and a clay-containing liquid suitable for producing a clay film could not be obtained.

EXAMPLE 6

Natural montmorillonite (Kunipia F manufactured by Kunimine Kogyo Co., Ltd.) was used as clay, and epsilon caprolactam (manufactured by Wako Pure Chemical Industries, Ltd.) was used as an additive.

27.4 g of clay and 600 ml of pure water were put together with a rotor in a plastic sealed container and shaken vigorously at 25 ° C. for 2 hours to obtain a uniform clay dispersion. Further, 1.44 g of epsilon caprolactam and 58 ml of pure water were placed in a sealed container made of plastic together with a rotor, and stirred with a stirrer to obtain a uniform additive-containing liquid.

Subsequently, the clay dispersion and the additive-containing liquid were placed together with the rotor in a plastic sealed container, and shaken vigorously at 25 ° C. for 1 hour, followed by further stirring for 20 minutes at a rotational speed of 10000 rpm using a homogenizer to contain uniform clay. A liquid was obtained. At this time, the clay-containing liquid was exothermic, the temperature was raised to about 90 ° C., and the viscosity of the clay-containing liquid was lowered. And the clay containing liquid of about 90 degreeC was put into the vacuum degassing apparatus, and deaeration was performed for 40 minutes under the reduced pressure of 0.08 Mpa or less. After about 15 minutes had elapsed since the start of degassing, the generation of bubbles from the clay-containing liquid was hardly confirmed.

Next, this clay-containing liquid was applied to the flat portion of the surface of the brass tray. A stainless steel spatula was used to apply the clay-containing liquid, and a clay-containing liquid film having a uniform thickness was formed by using a spacer as a guide. This tray was put into a forced-air oven, and it heated and dried for about 6 hours on 60 degreeC temperature conditions. The resulting clay film was peeled off from the tray to obtain a uniform clay film having a thickness of about 30 μm. Since the obtained clay film had sufficient mechanical strength, it could be used as a self-supporting film and was excellent in flexibility.

This clay film was heated to 300 degreeC at the temperature increase rate of about 18 degreeC per minute, and observed after hold | maintaining at 300 degreeC for 1 hour. Then, although the clay film was slightly blackened, the swelling which can be confirmed visually was not confirmed. As a result of observing the cross section of this clay film with a scanning electron microscope (SEM), it turned out that the inside is quite uniform (refer FIG. 4).

In order to confirm the dimensional stability of this clay film, the linear expansion coefficient was measured similarly to Example 1. The sample width was 3 mm and the load was 5 g. It heated to 148 degreeC at the temperature increase rate of 5 degreeC / min, and hold | maintained the temperature for 1 hour, and then cooled to 38 degreeC. And it heated immediately to 299 degreeC at the temperature increase rate of 5 degree-C / min, and measured the linear expansion coefficient. As a result, the linear expansion coefficient in the temperature range of 40 degreeC-299 degreeC was 1.2-8.0 ppm / degreeC.

This clay film was analyzed by X-ray diffraction in the same manner as in Example 1 to confirm whether the layers of the clay crystals were highly oriented and densely stacked. In the obtained X-ray diffraction spectrum (see Fig. 5), a clear peak was confirmed at a position of 1.48 (1.36 nm in terms of interlayer distance) at 2θ, and a layer of clay crystals in the clay film was highly laminated and precisely aligned. It was shown.

Moreover, similarly to Example 1, when the electron micrograph of the cross section of the clay film | membrane was photographed, it turned out similarly that the layer of a clay crystal is orientated and closely laminated | stacked at an average interlayer distance of about 1.2 nm. (Refer FIG. 6). The average interlayer distance estimated from the electron micrograph is slightly smaller than that from the analysis by X-ray diffraction, because the analysis by X-ray diffraction is in the air and the electron micrographing is performed in a high vacuum state. That is, since the moisture mixed in the clay film volatilized in a vacuum state, it is presumed that the reason was that the average interlayer distance decreased slightly.

In order to confirm the gas barrier property of this clay film, the transmission coefficient of oxygen was measured similarly to Example 1. As a result, it was confirmed that the oxygen transmission coefficient at room temperature was less than 3.2 × 10 ⁻¹¹ cm 2 s ⁻¹ cmHg ⁻¹ , indicating high gas barrier performance.

(Comparative Example 7)

In the same manner as in Example 6, a clay-containing liquid was obtained. After stirring with a homogenizer, the clay-containing liquid whose temperature has risen to about 90 ° C. is left to stand at room temperature for about 30 minutes, lowered to about 30 ° C., and then placed in a vacuum degassing apparatus under a reduced pressure of 0.08 MPa or less. Degassing was performed for 40 minutes. Occurrence of bubbles from the clay-containing liquid was confirmed to the end although low in frequency during degassing.

In the same manner as in Example 6, a uniform clay film having a thickness of about 30 μm was obtained using this clay-containing liquid. Since the obtained clay film had sufficient mechanical strength, it could be used as a self-supporting film and was excellent in flexibility.

This clay film was heated to 300 degreeC at the temperature increase rate of about 18 degreeC per minute, and observed after hold | maintaining at 300 degreeC for 1 hour. Then, the clay film was slightly blackened, and a large number of spots of circular swelling about 1 to 5 mm in diameter were confirmed. As a result of observing the cross section of this film by SEM, many thin pores were observed (see Fig. 7). In the case where the gas components contained in the clay-containing liquid are insufficient to be removed, most of the bubbles (voids) derived from the gas component mixed into the clay-containing liquid remain inside the clay film, and the circular swelling described above when heated. It indicates that there is a possibility of occurrence.

EXAMPLE 7

Hydrophobic hectorite (lucentite SAN manufactured by Cope Chemical Co., Ltd.) was used as clay, and Asaflex L451 (made by Asahi Kasei Chemicals Co., Ltd.) was used as an additive.

8.5 g of clay was put into a Erlenmeyer flask with a mixed solvent of 62 g of toluene and 12 g of methanol, and stirred at about 25 ° C. for 2 hours by a rotor to obtain a uniform clay dispersion. In addition, 1.5 g of Asaplex L451 and 16 g of toluene were placed in a Erlenmeyer flask, and stirred by a rotor for 1 hour to obtain a uniform additive-containing liquid.

Subsequently, this clay dispersion liquid and the additive containing liquid were mixed in another Erlenmeyer flask, and stirred by the rotor at about 25 degreeC for 2 hours, and the uniform clay containing liquid was obtained. And this clay containing liquid was degassed for several minutes, stirring under reduced pressure.

The inner surface of the brass tray like the one used in Example 4 was covered with aluminum foil, and a portion of the aluminum foil facing the bottom surface of the tray was flattened. The PET film as used in Example 3 was placed in a tray (that is, placed on an aluminum foil) and a clay-containing liquid was applied to the PET film. The clay containing liquid film of uniform thickness was formed by using a glass rod for the application | coating of a clay containing liquid, and using a spacer as a guide.

This tray was placed on a hot plate, heated at 80 ° C. for about 30 minutes, and dried. The resulting clay film was peeled from the PET film to obtain a uniform clay film having a thickness of about 57 μm. Since the obtained clay film had sufficient mechanical strength, it could be used as a self-supporting film and had flexibility.

In order to confirm the transparency of the clay film, the transmittance was measured in the same manner as in Example 1, and the transmittance was 85% or more in the range of 360 nm to 800 nm, and coloring was not confirmed. In addition, it was 90.1% when the total light transmittance was measured similarly to Example 1, and 1.6% when the haze (doughness) was measured.

The clay film was heated in the air at 200 ° C. for 30 minutes in the air, and similarly, when the transmittance was measured, it had a transmittance of 85% or more in the range of 420 nm to 800 nm, and coloring was not confirmed. In addition, it was 91.1% as a result of measuring the total light transmittance similarly, and 1.7% as a result of measuring haze (doughness).

In addition, when the clay membrane was immersed in water at 24 ° C. for 24 hours, there was no change visible to the naked eye, and it was found that the strength was not lowered and the water resistance was high. The absorption rate according to the immersion calculated from the weight change before and after immersion was about 1.9%.

(Comparative Example 8)

Hydrophobic hectorite (lucentite SAN manufactured by Cope Chemical Co., Ltd.) was used as clay, and Asaplex L451 (made by Asahi Kasei Chemicals Co., Ltd.) was used as an additive.

8.0 g of clay and 80 g of toluene were placed in a Erlenmeyer flask, and stirred by a rotor at about 25 ° C. for 3 hours to obtain a uniform clay dispersion. In addition, 1.5 g of Asaplex L451 and 10 g of toluene were placed in a Erlenmeyer flask, and stirred by a rotor at about 25 ° C. for 1 hour to obtain a uniform additive-containing liquid.

Using this clay-containing liquid, in the same manner as in Example 7, a uniform clay film having a thickness of about 84 μm was obtained. Since the obtained clay film had sufficient mechanical strength, it could be used as a self-supporting film and had flexibility.

In order to confirm the transparency of the clay film, the transmittance was measured in the same manner as in Example 1, and as a result, there was no region having a transmittance of 85% or more, and coloring was not confirmed. In addition, it was 90.8% as a result of measuring the total light transmittance similarly to Example 1, and 23.8% as a result of measuring haze (lightness).

EXAMPLE 8

In the same manner as in Example 1, the clay-containing liquid of the same composition was adjusted. The same PET film as Example 3 was placed in a B4 sized brass tray (PET film was not fixed to the tray with an adhesive tape), and the clay-containing liquid was applied to the surface on which the silicone resin of the PET film was applied. A stainless steel spatula was used for application of the clay-containing liquid and a clay-containing liquid film of uniform thickness was formed by using a spacer as a guide.

The tray was placed in a forced-air oven, heated at a temperature of 60 ° C. for about 6 hours, and dried in a state where the PET film serving as the support was deformable. Immediately after the end of drying, the PET film was integrated and curved with the clay film, and a part thereof was separated without contacting the bottom of the tray. After the resulting clay film was taken out together with the PET film, it was left in the air for 30 minutes, and when there was almost no curvature, the clay film was peeled off from the PET film to obtain a uniform clay film having a thickness of about 22 μm.

 The obtained clay film had the mechanical strength which can be used as a freestanding film. Moreover, transparency was high and was excellent in flexibility. In addition, cracks and cracks were not found throughout the film.

In order to confirm the flexibility of the clay membrane, the curvature was bent into a cylindrical shape having a radius of 6 mm, but no cracks or the like occurred and no defects occurred. In the same manner as in Example 1, when the transmittance was measured, the transmittance at a wavelength of 500 nm was 89.3%, and the transmittance was 80% or more in the range of 264 nm to 800 nm. The total light transmittance of the clay film measured in the same manner as in Example 1 was 92.0%, and haze (doughness) was 1.6%.

(Comparative Example 9)

A tray made of a polypropylene of B4 size, which had a frame around it and was too thick and could not be easily deformed, was prepared. And the clay containing liquid similar to what was used in Example 8 was apply | coated to the flat part of the surface of this tray. A stainless steel spatula was used for application of the clay-containing liquid and a clay-containing liquid film of uniform thickness was formed by using a spacer as a guide.

This tray was put into a forced-air oven, and heated and dried for about 6 hours at 60 degreeC temperature conditions. At the end of drying, the tray was not deformed, almost the entire surface of the clay film was attached to the surface of the tray, and cracks were formed in part of the clay film. The resulting clay film was peeled off from the tray to obtain a uniform clay film having a thickness of about 22 μm. The obtained clay film had the mechanical strength which can be used as a freestanding film. Moreover, transparency was high and was excellent in flexibility. However, as mentioned above, since cracks were generated in part of the clay film, the clay film was divided into plural parts, so that the B4 size clay film could not be obtained.

In order to confirm the flexibility of the clay membrane, the curvature was bent into a cylindrical shape with a radius of 6 mm, but no new cracks were generated. When the transmittance was measured in the same manner as in Example 1, the transmittance at a wavelength of 500 nm was 89.0%, and the transmittance was 85% or more in the range of 312 nm to 800 nm. The total light transmittance of the clay film measured in the same manner as in Example 1 was 91.7%, and the haze (doughness) was 2.3%.

EXAMPLE 9

In the same manner as in Example 8, a uniform clay film (primary dry film) having a thickness of about 21 μm was obtained. The obtained clay film had the mechanical strength which can be used as a freestanding film. Moreover, transparency was high and was excellent in flexibility. The total light transmittance of the clay film measured in the same manner as in Example 1 was 91.5%, and the haze was 1.8%. In addition, the surface roughness of the clay film measured with the surface roughness meter "alpha step IQ" made from KLA Tencol Co., was Ra at 39 nm.

Immediately after film formation, the clay film was immersed in pure water for about 5 seconds, pulled up, and sandwiched between PET films as described above, wherein a silicone resin was applied to the surface. At this time, the smooth surface of both PET films was made to contact a clay film. Subsequently, the roller of which the surface was smooth was rolled on PET film, the clay film was spread out, and the excess moisture was pushed out, one PET film was peeled off, and it left to stand at about 20 degreeC for one day, and dried. The dried clay film was peeled off from the other PET film to obtain a uniform clay film having a thickness of about 10 μm. The obtained transparent clay film had the tensile strength of 32 MPa, and had the mechanical strength which can be used as a freestanding film. Moreover, transparency was high and was excellent in flexibility.

In order to confirm the flexibility of the transparent clay film, it was curved in a cylindrical shape with a radius of 6 mm, but no cracks or the like occurred and no defects occurred. In addition, in order to confirm the transparency of the clay film, the transmittance in the wavelength range of 190 nm to 800 nm was measured in the same manner as in Example 1, and the transmittance was 85% or more in the range of 312 nm to 800 nm, and coloring was not confirmed. Did. In addition, the total light transmittance of the transparent clay film measured similarly to Example 1 was 91.7%, and haze was 1.5%. In addition, the surface roughness of the clay film measured similarly was 35 nm in Ra.

After leaving this transparent clay film for one week in a clean room maintained at 1 atmosphere, a temperature of 24 ° C. and a humidity of 45%, the total light transmittance and the haze were measured in the same manner as described above, and the total light transmittance was 91.8%. 1.6%. In addition, when the same measurement was performed after leaving for 1 month, the total light transmittance was 91.9% and haze was 1.5%.

(Comparative Example 10)

In the same manner as in Example 8, a uniform clay film having a thickness of about 19 μm was obtained. The obtained clay film had the mechanical strength which can be used as a freestanding film. Moreover, transparency was high and was excellent in flexibility. The total light transmittance of the clay film measured in the same manner as in Example 1 was 91.7%, and haze was 2.3%. In addition, the surface roughness of the clay film measured similarly to Example 9 was 47 nm in Ra.

The clay membrane was left in a clean room maintained at 24 ° C., 1 atm, and 45% humidity. As a result, the haze increased to 16.8% after 1 week and to 24.3% after January. In addition, the surface roughness of the clay film after 1 month standing was 109 nm in Ra.

EXAMPLE 10

The primary dry film produced in the same manner as in Comparative Example 9 was left to stand for 1 month in a clean room maintained at 1 atmosphere, temperature of 24 ° C. and humidity of 45%. As a result, a clay film having a thickness of about 23 μm with a haze increased to 26.5% was obtained. Pure water was sprayed to wash the surface of the clay film and the clay film was swollen, and then the silicone resin was sandwiched between PET films coated on the surface. At this time, the smooth surface of both PET films was made to contact a clay film.

Subsequently, in the same manner as in Example 9, a glass roller having a smooth surface was rolled on the PET film to expand the clay film to push out excess moisture, and then one PET film was peeled off and left at 24 ° C. for one day to dry. The dried clay film was peeled off from the other PET film to obtain a uniform clay film having a thickness of about 12 μm. The tensile strength of the obtained transparent clay film was 22 MPa, and had mechanical strength which can be used as a freestanding film. Moreover, transparency was high and was excellent in flexibility.

In order to confirm the flexibility of the transparent clay film, it was curved in a cylindrical shape with a radius of 6 mm, but no cracks or the like occurred and no defects occurred. In addition, in order to confirm the transparency of the clay film, the transmittance in the wavelength range of 190 nm to 800 nm was measured in the same manner as in Example 1, and the transmittance was 85% or more in the range of 328 nm to 800 nm, and coloring was not confirmed. Did. In addition, the total light transmittance of the transparent clay film measured similarly to Example 1 was 91.8%, and haze was 0.63%. In addition, the surface roughness of the clay film measured similarly to Example 1 was Ra in 23 nm.

After leaving this transparent clay film for 1 week in a clean room maintained at 1 atmosphere, a temperature of 24 ° C. and a humidity of 45%, the total light transmittance and the haze were measured in the same manner as described above, and the total light transmittance was 91.7%. 0.68%. Moreover, as a result of performing the same measurement after leaving for one, the total light transmittance was 91.9% and haze was 0.65%.

Comparative Example 11

In the same manner as in Comparative Example 2, a uniform clay film having a thickness of about 17 μm was obtained. The obtained clay film had the mechanical strength which can be used as a freestanding film. Moreover, transparency was high and was excellent in flexibility. The total light transmittance of the clay film measured in the same manner as in Example 1 was 91.8%, and haze was 7.0%. In addition, the surface roughness of the clay film measured similarly to Example 9 was 55 nm in Ra.

The clay membrane was left in a clean room maintained at 24 ° C., 1 atm, and 45% humidity. As a result, the haze increased to 21.4% after one week and to 27.0% after one month. In addition, the surface roughness of the clay film after 1 month standing was 122 nm in Ra.

EXAMPLE 11

In Comparative Example 11, the primary dry film having a haze increased to 27.0% was immersed with pure water for about 5 seconds, pulled up, and sandwiched between PET films coated with silicone resin on the surface. At this time, the smooth surface of both PET films was made to contact a clay film. Subsequently, a glass roller having a smooth surface was rolled on the PET film to expand the clay film to push out excess moisture, and then one PET film was peeled off, and left to dry at about 20 ° C. for one day. The dried clay film was peeled off from the other PET film to obtain a uniform clay film having a thickness of about 12 μm. The tensile strength of the obtained transparent clay film was 35 MPa, and had mechanical strength which can be used as a freestanding film. Moreover, transparency was high and was excellent in flexibility.

In order to confirm the flexibility of the transparent clay film, it was curved in a cylindrical shape with a radius of 6 mm, but no cracks or the like occurred and no defects occurred. In addition, in order to confirm the transparency of the clay film, the transmittance in the wavelength range of 190 nm to 800 nm was measured in the same manner as in Example 1, and the transmittance was 85% or more in the range of 321 nm to 800 nm, and coloring was not confirmed. Did. In addition, the total light transmittance of the transparent clay film measured similarly to Example 1 was 92.0%, and haze was 0.83%. In addition, the surface roughness of the clay film measured in the same manner as in Example 9 was 32 nm in Ra.

After leaving this transparent clay film for 1 week in a clean room maintained at 1 atmosphere, temperature of 24 ° C. and humidity of 45%, the total light transmittance and haze were measured in the same manner as described above, and the total light transmittance was 92.0%, and the haze was 0.86. Was%. In addition, when the same measurement was performed after leaving for 1 month, the total light transmittance was 92.1% and the haze was 0.84%.

EXAMPLE 12

In Comparative Example 11, the surface was washed with a primary dry film having a haze increased to 27.0% so that pure water was sprayed, the clay film was swollen, and a silicone resin was sandwiched between PET films coated on the surface. At this time, the smooth surface of both PET films was made to contact a clay film. Subsequently, in the same manner as in Example 1, a glass roller having a smooth surface was rolled on the PET film to expand the clay film to push out excess moisture, and then one PET film was peeled off and left at about 20 ° C. for one day to dry. The dried clay film was peeled off from the other PET film to obtain a uniform clay film having a thickness of about 10 μm. The tensile strength of the obtained transparent clay film was 31 MPa, and had mechanical strength which can be used as a freestanding film. Moreover, transparency was high and was excellent in flexibility.

In order to confirm the flexibility of the transparent clay film, it was curved in a cylindrical shape with a radius of 6 mm, but no cracks or the like occurred and no defects occurred. In addition, in order to confirm the transparency of the clay film, the transmittance in the wavelength range of 190 nm to 800 nm was measured in the same manner as in Example 1, and the transmittance was 85% or more in the range of 305 nm to 800 nm, and coloring was not confirmed. Did. In addition, the total light transmittance of the transparent clay film measured similarly to Example 1 was 91.9%, and haze was 0.62%. In addition, the surface roughness of the clay film measured similarly to Example 1 was 26 nm in Ra.

After leaving the transparent clay film in a clean room maintained at 1 atmosphere, temperature of 24 ° C. and humidity of 45% for 1 week, the total light transmittance and haze were measured in the same manner as described above, and the total light transmittance was 92.0%. 0.64%. In addition, when the same measurement was performed after leaving for 1 month, the total light transmittance was 92.1% and the haze was 0.65%.

In the clay film production method of the present invention, clay and additives are uniformly dispersed, defects such as cracking and cracking are less likely to occur, and a clay film having strength that can be used as a freestanding film can be produced. Moreover, the clay film of this invention is a clay film which clay and an additive are disperse | distributed uniformly, are few defects, such as a crack and a crack, and have the strength which can be used as a freestanding film. In addition to this, it is a transparent clay film having a high light transmittance and a small haze, and hardly increasing with time of the haze even if it is left in the air.

Claims (32)

The clay dispersion liquid which disperse | distributed the clay to the solvent, and the additive containing liquid which disperse | distributed or melt | dissolved the additive in the solvent were prepared, respectively, and the said ratio of the said additive in the total amount of the said clay and the said additive is more than 0 mass% and 50 mass% or less. A clay-containing liquid adjustment step of mixing a clay dispersion and the additive-containing liquid to obtain a clay-containing liquid; And And a drying step of removing and drying the solvent after disposing the clay-containing liquid on the surface of the support. The clay dispersion liquid which disperse | distributed the clay to the solvent, and the additive containing liquid which disperse | distributed or dissolved the additive in the solvent were prepared, respectively, and the said ratio of the said additive in the total amount of the said clay and the said additive is more than 0 mass% and 30 mass% or less. A clay-containing liquid adjustment step of mixing a clay dispersion and the additive-containing liquid to obtain a clay-containing liquid; And And a drying step of removing and drying the solvent after disposing the clay-containing liquid on the surface of the support. The clay film production method according to claim 1 or 2, further comprising a degassing step of reducing a gas contained in the clay-containing liquid. The manufacturing method of the clay film of any one of Claims 1-3 which has a peeling process which peels the dry matter obtained by the said drying process from the said support body. The clay film according to any one of claims 1 to 4, wherein in the clay-containing liquid adjusting step, the clay-containing liquid is obtained by mixing the clay dispersion liquid and the additive-containing liquid at a temperature higher than normal temperature. Method of preparation. 4. The method for producing a clay film according to claim 3, wherein the clay-containing liquid is brought to a temperature higher than room temperature and is placed under reduced pressure to reduce the gas contained in the clay-containing liquid. The method of producing a clay film according to claim 3, wherein the clay-containing liquid is reduced to a temperature higher than room temperature and the gas contained in the clay-containing liquid is reduced by stirring under reduced pressure. The method for producing a clay film according to claim 4, wherein the support has flexibility and the dried material is peeled from the support after drying in a state in which the support is deformable. The method for producing a clay film according to claim 8, wherein the support is a resin film. 10. The method for producing a clay film according to claim 8 or 9, wherein an easy peeling treatment is applied to the support. The method for producing a clay film according to claim 8 or 9, wherein the support is subjected to a water repellent treatment. The redrying process according to any one of claims 1 to 11, wherein a liquid for swelling the clay or a liquid for dissolving or dispersing the additives is disposed on the surface of the dried product obtained by the drying process, and a redrying process is carried out. It has a manufacturing method of the clay film characterized by the above-mentioned. The clay film production method according to claim 12, wherein the liquid is disposed on the surface of the dried product by immersion in the liquid. The clay film production method according to claim 12, wherein the liquid is disposed on the surface of the dried product by spraying the liquid. 15. The liquid according to any one of claims 12 to 14, wherein after the liquid is smoothed by placing the liquid on the surface, the dried material at least partially swelled is brought into contact with a smooth member having a smooth surface to smooth the surface thereof. It is made to dry, The manufacturing method of the clay film | membrane. The method of claim 15, wherein the smoothing member is flexible and deformable, and the liquid is re-dried in a state in which the dried material is in contact with the smoothing member. The clay film production method according to any one of claims 1 to 16, wherein the clay is a hydrophilic clay which has high affinity for water and is easily dispersed in water. The clay film production method according to any one of claims 1 to 16, wherein the clay is hydrophobic clay which has high affinity for an organic solvent and is easily dispersed in an organic solvent. 19. The hydrophobic clay according to claim 18, wherein the affinity and dispersibility of an organic solvent are improved by exchanging inorganic ions included in hydrophilic clay with organic ions, and the organic ions are ammonium ions, phosphonium ions, or imide. A method for producing a clay film, which contains one or more of zoleum ions. The clay film obtained is transparent, The manufacturing method of the clay film in any one of Claims 1-19 characterized by the above-mentioned. A clay film produced by the method for producing a clay film according to any one of claims 1 to 20: A clay film formed by laminating layered clay crystals in a film thickness direction. 22. The clay film according to claim 21, wherein the average linear expansion coefficient of 30 DEG C to 250 DEG C is 10 ppm or less. The haze is 5% or less, the total light transmittance is 85% or more, and the light transmittance in the wavelength range of 400 nm or more and 800 nm or less is 85% or more and 95% or less. Clay film. The haze is 2% or less, the total light transmittance is 85% or more, and the light transmittance in the wavelength range of 400 nm or more and 800 nm or less is 85% or more and 95% or less. Clay film. The haze is less than 1%, the total light transmittance is 85% or more, and the light transmittance in the wavelength range of 400 nm or more and 800 nm or less is 85% or more and 95% or less. Clay film. The clay film according to any one of claims 23 to 25, wherein the change in haze over time in an environment of 24 ° C, 1 atmosphere, and humidity of 45% is -2% or more and 2% or less. 27. The clay film according to any one of claims 21 to 26, wherein the film thickness is thicker than 15 mu m. At least one part is comprised from the clay film obtained by the manufacturing method of the clay film of any one of Claims 1-20, or the clay film of any one of Claims 21-27. Paper. At least a part is comprised by the clay film obtained by the manufacturing method of the clay film of any one of Claims 1-20, or the clay film of any one of Claims 21-27, The flexible thing characterized by the above-mentioned. Board. At least a part is comprised by the clay film obtained by the manufacturing method of the clay film of any one of Claims 1-20, or the clay film of any one of Claims 21-27, The flexible thing characterized by the above-mentioned. Printed board. An electronic device comprising a non-light-emitting organic semiconductor or an amorphous inorganic semiconductor is mounted and has a gas barrier property: a clay film obtained by the method for producing a clay film according to any one of claims 1 to 20, or At least one part is comprised from the clay film of any one of Claims 21-27, The board | substrate characterized by the above-mentioned. A gas barrier film for protecting an electronic device comprising a non-light emitting organic semiconductor or an amorphous inorganic semiconductor from a gas: a clay film obtained by the method for producing a clay film according to any one of claims 1 to 20, or a twenty-first At least one part is comprised from the clay film of any one of Claims 27-27, The gas barrier film characterized by the above-mentioned.

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