JP2012082258A - Liquid-absorptive communicating porous body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid-absorptive communicating porous body excellent in heat resistance and also liquid absorbing ability for both oil and water.SOLUTION: This liquid-absorptive communicating porous body includes a porous body having spherical bubbles, the oil- and water-absorbance of which are each 100 wt.% or more.

Description

  The present invention relates to a liquid-absorbing continuous porous body. More specifically, the present invention relates to a liquid-absorbing continuous porous body that is excellent in heat resistance and liquid-absorbing with respect to both oil and moisture.

  Various liquid-absorbing materials using an oil-absorbing resin and a water-absorbing resin have been reported as liquid-absorbing materials that absorb and collect oil and moisture. However, most liquid-absorbing materials have problems such as liquid return due to large volume expansion due to liquid absorption. Moreover, most liquid-absorbing materials can be used only once, causing a problem that they are difficult to reuse.

  Thus, it has been reported that by using a porous structure of a polyolefin resin as the liquid absorbing material, the liquid retentivity is enhanced and the reabsorbability after use is imparted (Patent Document 1).

  However, since the porous structure of Patent Document 1 absorbs only oil, it cannot be used in a scene where it is necessary to absorb both oil and moisture. Moreover, since the porous structure of patent document 1 is not fully controlled, the liquid retention property is not sufficient. Furthermore, after releasing the absorbent after use, it does not have the reversibility of the porous structure so that sufficient resorbability can be exhibited. In addition, since the heat resistance is not sufficient, there is a problem that the dimensional stability is inferior when placed under a high temperature.

JP 2008-231194 A

  The subject of this invention is providing the liquid-absorbing continuous porous body which is excellent in heat resistance, and is excellent in the liquid absorptivity with respect to both an oil component and a water | moisture content.

The liquid-absorbing continuous porous body of the present invention is
Including a porous body having spherical bubbles,
The oil and moisture absorption rates are both 100% by weight or more.

  In a preferred embodiment, the liquid-absorbing continuous porous body of the present invention releases the liquid L absorbed by heat drying after having absorbed the liquid L at a liquid absorption rate of A wt%, and then again the liquid L When the liquid is absorbed, the liquid absorption is 0.9 A% by weight or more.

  In a preferred embodiment, the liquid-absorbing continuous porous body of the present invention has a dimensional change rate after oil absorption of 50% or less.

  In a preferred embodiment, the liquid-absorbing continuous porous body of the present invention has a dimensional change rate of 10% or less after water absorption.

  In a preferred embodiment, the dimensional change when stored at 125 ° C. for 22 hours is less than ± 5%.

  In a preferred embodiment, the porous body contains a hydrophilic polyurethane polymer.

  In a preferred embodiment, the average pore diameter of the spherical bubbles is less than 20 μm.

  In a preferred embodiment, the porous body has an open cell structure having a through hole between adjacent spherical cells.

  In preferable embodiment, the average hole diameter of the said through-hole is 5 micrometers or less.

In preferable embodiment, the density of the said porous body is 0.15-0.5 g / cm < ³ >.

  ADVANTAGE OF THE INVENTION According to this invention, while being excellent in heat resistance, the liquid absorbing continuous porous body which is excellent in the liquid absorptivity with respect to both an oil component and a water | moisture content can be provided.

It is a schematic sectional drawing which shows preferable embodiment of the liquid absorptive continuous porous body of this invention. It is a schematic sectional drawing which shows another preferable embodiment of the liquid absorptive continuous porous body of this invention. 1 is a photograph of a surface / cross-sectional SEM photograph obtained by obliquely photographing the liquid-absorbing continuous porous material produced in Example 1. FIG. It is a photograph of the cross-sectional SEM photograph of the liquid-absorbing continuous porous body of the present invention, and is a photograph that clearly represents an open-cell structure having through holes between adjacent spherical bubbles.

≪ << A. Liquid-absorbing continuous porous material >>
The liquid-absorbing continuous porous body of the present invention includes a porous body having spherical bubbles. The porous body contained in the liquid-absorbing continuous porous body of the present invention preferably has an open cell structure having through holes between adjacent spherical cells. Typical structures include a liquid-absorbing continuous porous body 100 (FIG. 1) made of the porous body 10 and a liquid-absorbing continuous porous body including a base material 20 (described later) between the porous body 10a and the porous body 10b. 100 (FIG. 2). In FIGS. 1 and 2, the release film 30 is provided for protecting the surface of the liquid-absorbing continuous porous body, but the release film may not be provided.

  In the present specification, the “spherical bubble” does not have to be a strict true spherical bubble, and may be, for example, a substantially spherical bubble having a partial strain or a bubble composed of a space having a large strain. .

  The average pore diameter of the spherical bubbles that the porous body contained in the liquid-absorbing continuous porous body of the present invention may have is less than 20 μm, preferably 15 μm or less, more preferably 10 μm or less. The lower limit value of the average pore diameter of the spherical bubbles contained in the porous body contained in the liquid-absorbing continuous porous body of the present invention is not particularly limited, and is preferably 0.01 μm, more preferably 0.1 μm, and further, Preferably it is 1 micrometer.

  When the average pore diameter of the spherical bubbles contained in the porous body contained in the liquid-absorbing continuous porous body of the present invention falls within the above range, the average pore diameter of the spherical bubbles of the porous body contained in the liquid-absorbing continuous porous body of the present invention. It is possible to provide a liquid-absorbing continuous porous body that can be controlled to be precisely small, has excellent heat resistance, and has excellent liquid absorbency with respect to both oil and moisture.

The density of the porous body contained in the absorbent continuous porous body of the present invention is preferably 0.15~0.5g / cm ^3, more preferably 0.15g ^/ cm ³ ~0.45g ^/ cm 3 There, more preferably from ^{0.15g / cm 3 ~0.4g / cm 3} . After the density of the porous body contained in the liquid-absorbing continuous porous body of the present invention falls within the above range, the range of the density of the porous body contained in the liquid-absorbing continuous porous body of the present invention is widely controlled, It is possible to provide a liquid-absorbing continuous porous body that is excellent in heat resistance and excellent in liquid absorbency with respect to both oil and moisture.

  The porous body contained in the liquid-absorbing continuous porous body of the present invention preferably has an open cell structure having through holes between adjacent spherical cells. This open cell structure may be an open cell structure having through holes between most or all adjacent spherical cells, or may be a semi-independent semi-open cell structure having a relatively small number of through holes. .

  The through-hole which has between adjacent spherical bubbles influences the physical property of a liquid-absorbing continuous porous body. For example, the smaller the average pore diameter of the through-holes, the higher the strength of the liquid-absorbing continuous porous body. FIG. 4 is a photographic view of a cross-sectional SEM photograph of the liquid-absorbing continuous porous body of the present invention, and a photographic view clearly showing an open-cell structure having through holes between adjacent spherical bubbles.

  The average pore diameter of the through holes between adjacent spherical bubbles is preferably 5 μm or less, more preferably 4 μm or less, and even more preferably 3 μm or less. The lower limit value of the average pore diameter of the through holes between adjacent spherical bubbles is not particularly limited, and is preferably 0.001 μm, and more preferably 0.01 μm, for example. By providing an average pore diameter of through-holes between adjacent spherical bubbles within the above range, it is possible to provide a liquid-absorbing continuous porous body that has excellent heat resistance and liquid absorbency with respect to both oil and moisture. it can.

  The liquid-absorbing continuous porous body of the present invention preferably has a surface opening on the surface. The average pore diameter of the surface opening is preferably 20 μm or less, more preferably less than 20 μm, further preferably 15 μm or less, further preferably 10 μm or less, further preferably 5 μm or less, and particularly preferably. Is 4 μm or less, and most preferably 3 μm or less. The lower limit of the average pore diameter of the surface opening is not particularly limited, and is preferably 0.001 μm, and more preferably 0.01 μm, for example. The liquid-absorbing continuous porous body of the present invention has a surface opening, and the average pore diameter of the surface opening is within the above range, so that the heat-absorbing continuous porous body is excellent in heat resistance and absorbs both oil and moisture. It is possible to provide a liquid-absorbing continuous porous body that is excellent in the above.

  The liquid-absorbing continuous porous body of the present invention is excellent in liquid-absorbing properties for both oil and moisture. Here, in the present invention, “oil” means a so-called oily liquid, and “moisture” means a so-called aqueous liquid.

  In the liquid-absorbing continuous porous material of the present invention, both the oil and moisture absorption rates are 100% by weight or more.

  In the liquid-absorbing continuous porous body of the present invention, the oil absorption rate is preferably 150% by weight or more, more preferably 200% by weight or more, still more preferably 250% by weight or more, and particularly preferably. 300% by weight or more. The upper limit of the oil absorption rate is not particularly limited, and it is preferably as large as possible, but in practice it is preferably 200% by weight.

  The liquid-absorbing continuous porous body of the present invention has a water absorption rate of preferably 120% by weight or more, more preferably 150% by weight or more, still more preferably 170% by weight or more, and particularly preferably. 200% by weight or more. The upper limit of the moisture absorption rate is not particularly limited, and it is preferably as large as possible. However, practically, it is preferably 150% by weight.

  The liquid-absorbing continuous porous body of the present invention has a very high oil absorption rate and water absorption rate, and therefore can absorb oil and water continuously. That is, for example, after water is first absorbed at a liquid absorption rate of 100% by weight or more, the oil content is absorbed at a liquid absorption rate of 100% by weight or more (without releasing the absorbed liquid). can do. In this case, when the oil component is absorbed, the water absorbed in advance is not substantially separated.

  As described above, in the liquid-absorbing continuous porous body of the present invention, both the oil and moisture absorption ratios are very high because the liquid-absorbing continuous porous body of the present invention has an extremely precisely controlled porous structure. It is presumed to have Such a very precisely controlled porous structure can be produced, for example, by shaping and polymerizing a specific W / O emulsion as described below.

  A specific method for measuring the liquid absorption rate will be described later.

  The liquid-absorbing continuous porous body of the present invention preferably has a very excellent liquid-absorbing recoverability. Specifically, when the liquid is first absorbed at a liquid absorption rate of 100% by weight or more (first liquid absorption), the absorbed liquid is released, and then the liquid is again absorbed. (Second liquid absorption) can be absorbed at a level equivalent to the first liquid absorption rate.

  That is, the liquid-absorbing continuous porous material of the present invention absorbs the liquid L after absorbing the liquid L at a liquid absorption rate of A% by weight and then releases the liquid L absorbed by heating and drying, and then absorbs the liquid L again. The liquid absorption is preferably 0.9 A% by weight or more, more preferably 0.92 A% by weight or more, further preferably 0.95 A% by weight or more, particularly preferably 0.97 A% by weight. % Or more, and most preferably 0.99 A weight% or more. The upper limit of the liquid absorption rate when the liquid L is absorbed again is usually A wt%, but may be about 1.1 A wt% depending on the conditions.

  As described above, the liquid-absorbing continuous porous body of the present invention preferably has a very excellent liquid-absorbing recovery property because the liquid-absorbing continuous porous body of the present invention has a very precisely controlled porous structure. It is presumed to have Such a very precisely controlled porous structure can be produced, for example, by shaping and polymerizing a specific W / O emulsion as described below.

  The liquid-absorbing continuous porous body of the present invention has a dimensional change rate after oil absorption of preferably 50% or less, more preferably 40% or less, and further preferably 30% or less. The lower limit of the dimensional change rate after oil absorption is preferably 0%. When the rate of dimensional change after oil absorption is within the above range, volume expansion due to liquid absorption can be reduced, and problems such as liquid return can be suppressed.

  The liquid-absorbing continuous porous body of the present invention has a dimensional change rate after water absorption of preferably 10% or less, more preferably 7% or less, still more preferably 5% or less, particularly preferably. Is 3% or less. The lower limit of the dimensional change rate after moisture absorption is preferably 0%. When the dimensional change rate after water absorption is within the above range, volume expansion due to liquid absorption can be reduced, and problems such as liquid return can be suppressed.

  The liquid-absorbing continuous porous material of the present invention has a dimensional change rate of preferably less than ± 5%, more preferably ± 3% or less, and further preferably ± 1% when stored at 125 ° C. for 22 hours. It is as follows. In the liquid-absorbing continuous porous body of the present invention, the dimensional change rate when stored at 125 ° C. for 22 hours is within the above range, whereby the liquid-absorbing continuous porous body of the present invention can have excellent heat resistance.

  The porous body contained in the liquid-absorbing continuous porous body of the present invention has a cell ratio of preferably 30% or more, more preferably 40% or more, and further preferably 50% or more. In the liquid-absorbing continuous porous body of the present invention, providing the liquid-absorbing continuous porous body having excellent heat resistance and liquid-absorbing properties with respect to both oil and moisture by having the cell ratio within the above range. it can.

  The porous body contained in the liquid-absorbing continuous porous body of the present invention preferably contains a hydrophilic polyurethane polymer. Since the porous body contained in the liquid-absorbing continuous porous body of the present invention contains a hydrophilic polyurethane polymer, the cell structure is precisely controlled, the cell rate is high, and a large number of finely controlled cells are precisely controlled. It is possible to provide a liquid-absorbing continuous porous body that has a surface opening, has excellent heat resistance, and has excellent liquid absorbency with respect to both oil and moisture.

  The details of the porous body contained in the liquid-absorbing continuous porous body of the present invention and the details of the hydrophilic polyurethane polymer contained therein will be mentioned in the description of the production method described later.

  The liquid-absorbing continuous porous body of the present invention can take any appropriate shape. In the liquid-absorbing continuous porous material of the present invention, the length, such as the thickness, the long side, and the short side, can take any appropriate value.

  The liquid-absorbing continuous porous body of the present invention may contain any appropriate base material as long as the effects of the present invention are not impaired. Examples of the form in which the base material is contained in the liquid-absorbing continuous porous body of the present invention include a form in which a base layer is provided inside the liquid-absorbing continuous porous body. Examples of such a substrate include fiber woven fabric, fiber nonwoven fabric, fiber laminated fabric, fiber knitted fabric, resin sheet, metal foil film sheet, and inorganic fiber.

  As the fiber woven fabric, a woven fabric formed of any appropriate fiber can be adopted. Examples of such fibers include natural fibers such as plant fibers, animal fibers, and mineral fibers; artificial fibers such as regenerated fibers, synthetic fibers, semi-synthetic fibers, and artificial inorganic fibers. Examples of synthetic fibers include fibers obtained by melt spinning thermoplastic fibers. Further, the fiber woven fabric may be metallic processed by plating or sputtering.

  As a fiber nonwoven fabric, the nonwoven fabric formed from arbitrary appropriate fibers can be employ | adopted. Examples of such fibers include natural fibers such as plant fibers, animal fibers, and mineral fibers; artificial fibers such as regenerated fibers, synthetic fibers, semi-synthetic fibers, and artificial inorganic fibers. Examples of synthetic fibers include fibers obtained by melt spinning thermoplastic fibers. Moreover, the fiber nonwoven fabric may be metallic-processed by plating, sputtering, etc. More specifically, for example, a spunbond nonwoven fabric can be mentioned.

  As the fiber laminated fabric, a laminated fabric formed of any appropriate fiber can be adopted. Examples of such fibers include natural fibers such as plant fibers, animal fibers, and mineral fibers; artificial fibers such as regenerated fibers, synthetic fibers, semi-synthetic fibers, and artificial inorganic fibers. Examples of synthetic fibers include fibers obtained by melt spinning thermoplastic fibers. In addition, the fiber laminated fabric may be metallic processed by plating, sputtering, or the like. More specifically, for example, a polyester fiber laminated fabric can be mentioned.

  As a fiber knitted fabric, the knitted fabric formed from arbitrary appropriate fibers can be employ | adopted, for example. Examples of such fibers include natural fibers such as plant fibers, animal fibers, and mineral fibers; artificial fibers such as regenerated fibers, synthetic fibers, semi-synthetic fibers, and artificial inorganic fibers. Examples of synthetic fibers include fibers obtained by melt spinning thermoplastic fibers. Further, the fiber knitted fabric may be metallically processed by plating or sputtering.

  As the resin sheet, a sheet formed of any appropriate resin can be adopted. An example of such a resin is a thermoplastic resin. The resin sheet may be metallic processed by plating or sputtering.

  As the metal foil film sheet, a sheet formed from any appropriate metal foil film can be adopted.

  Any appropriate inorganic fiber can be adopted as the inorganic fiber. Specific examples of such inorganic fibers include glass fibers, metal fibers, and carbon fibers.

  In the liquid-absorbing continuous porous body of the present invention, when voids are present in the substrate, the same material as the liquid-absorbing continuous porous body may be present in part or all of the voids.

  Only 1 type may be used for a base material and it may use 2 or more types together.

≪≪B. Manufacturing method of liquid-absorbing continuous porous material >>
The liquid-absorbing continuous porous body of the present invention can be produced by any appropriate method. The liquid-absorbing continuous porous body of the present invention can be preferably produced by shaping and polymerizing a W / O emulsion.

  As a manufacturing method of the liquid-absorbing continuous porous body of the present invention, for example, it can be used for continuously supplying a continuous oil phase component and an aqueous phase component to an emulsifier to obtain the liquid-absorbing continuous porous body of the present invention. A “continuous method” is mentioned in which a W / O type emulsion is prepared, and then the obtained W / O type emulsion is polymerized to produce a water-containing polymer, followed by dehydration of the obtained water-containing polymer. It is done. As a method for producing the liquid-absorbing continuous porous body of the present invention, for example, an appropriate amount of the aqueous phase component is charged into the emulsifier with respect to the continuous oil phase component, and the aqueous phase component is continuously supplied while stirring. Thus, a W / O type emulsion that can be used to obtain the liquid-absorbing continuous porous body of the present invention is prepared, and the obtained W / O type emulsion is polymerized to produce a hydrous polymer. There is a “batch method” in which the obtained hydropolymer is dehydrated.

  The continuous polymerization method in which the W / O emulsion is continuously polymerized is a preferable method because the production efficiency is high and the effect of shortening the polymerization time and the shortening of the polymerization apparatus can be most effectively utilized.

More specifically, the liquid-absorbing continuous porous body of the present invention is preferably
A step (I) of preparing a W / O type emulsion that can be used to obtain the liquid-absorbing continuous porous body of the present invention;
Step (II) of shaping the obtained W / O emulsion,
Polymerizing the shaped W / O emulsion (III);
Step (IV) of dehydrating the obtained hydrous polymer;
It can manufacture with the manufacturing method containing. Here, at least a part of the step (II) for shaping the obtained W / O emulsion and the step (III) for polymerizing the shaped W / O emulsion may be performed simultaneously.

<< B-1. Step for preparing W / O type emulsion (I) >>
The W / O type emulsion that can be used for obtaining the liquid-absorbing continuous porous body of the present invention is a W / O type emulsion containing a continuous oil phase component and an aqueous phase component immiscible with the continuous oil phase component. More specifically, the W / O type emulsion is obtained by dispersing an aqueous phase component in a continuous oil phase component.

  The ratio of the water phase component to the continuous oil phase component in the W / O type emulsion that can be used to obtain the liquid-absorbing continuous porous body of the present invention is arbitrarily appropriate as long as the W / O type emulsion can be formed. A ratio can be taken. The ratio of the water phase component to the continuous oil phase component in the W / O emulsion that can be used to obtain the liquid-absorbing continuous porous body of the present invention is the structure of the porous body obtained by polymerization of the W / O emulsion. Can be an important factor in determining mechanical, mechanical, and performance characteristics. Specifically, the ratio of the water phase component to the continuous oil phase component in the W / O type emulsion that can be used to obtain the liquid-absorbing continuous porous body of the present invention is obtained by polymerization of the W / O type emulsion. It can be an important factor in determining the density, bubble size, bubble structure, and dimensions of the wall forming the porous structure.

  The ratio of the aqueous phase component in the W / O emulsion that can be used to obtain the liquid-absorbing continuous porous body of the present invention is preferably 30% by weight, more preferably 40% by weight, as the lower limit. More preferably, it is 50% by weight, particularly preferably 55% by weight, and the upper limit is preferably 95% by weight, more preferably 90% by weight, still more preferably 85% by weight, particularly preferably. Is 80% by weight. If the ratio of the aqueous phase component in the W / O emulsion that can be used to obtain the liquid-absorbing continuous porous body of the present invention is within the above range, the effects of the present invention can be sufficiently exhibited.

  The W / O emulsion that can be used to obtain the liquid-absorbing continuous porous body of the present invention can contain any appropriate additive as long as the effects of the present invention are not impaired. Examples of such additives include tackifying resins; talc; calcium carbonate, magnesium carbonate, silicic acid and salts thereof, clay, mica powder, aluminum hydroxide, magnesium hydroxide, zinc white, bentonine, carbon black, Examples thereof include fillers such as silica, alumina, aluminum silicate, acetylene black, and aluminum powder; pigments; dyes; Only one kind of such an additive may be contained, or two or more kinds thereof may be contained.

  Any appropriate method can be adopted as a method for producing a W / O emulsion that can be used to obtain the liquid-absorbing continuous porous material of the present invention. As a method for producing a W / O type emulsion that can be used for obtaining the liquid-absorbing continuous porous material of the present invention, for example, by supplying a continuous oil phase component and an aqueous phase component continuously to an emulsifier, "Continuous method" for forming O-type emulsions, or W / O type by supplying an appropriate amount of water phase components to the emulsifier and continuously supplying the water phase components with stirring to the continuous oil phase components Examples include “batch method” for forming an emulsion.

  When producing a W / O type emulsion that can be used to obtain the liquid-absorbing continuous porous body of the present invention, as a shearing means for obtaining an emulsion state, for example, a rotor-stator mixer, a homogenizer, a microfluidizer, etc. Application of the high shear conditions used can be mentioned. In addition, as another shearing means for obtaining an emulsion state, for example, gentle mixing of continuous and dispersed phases by application of low shear conditions using a moving blade mixer or a pin mixer, low stirring conditions using a magnetic stir bar, etc. Can be mentioned.

  Examples of the apparatus for preparing the W / O emulsion by the “continuous method” include a static mixer, a rotor stator mixer, and a pin mixer. More intense agitation may be achieved by increasing the agitation speed or by using an apparatus designed to finely disperse the aqueous phase component in the W / O emulsion by a mixing method.

  Examples of the apparatus for preparing the W / O type emulsion by the “batch method” include manual mixing and shaking, a driven blade mixer, and three propeller mixing blades.

  Arbitrary appropriate methods can be employ | adopted as a method of preparing a continuous oil phase component. As a method for preparing the continuous oil phase component, typically, for example, a mixed syrup containing a hydrophilic polyurethane-based polymer and an ethylenically unsaturated monomer is prepared, and subsequently, a polymerization initiator, It is preferable to prepare a continuous oil phase component by blending a crosslinking agent and any other appropriate components.

  Any appropriate method can be adopted as a method of preparing the hydrophilic polyurethane-based polymer. A typical method for preparing a hydrophilic polyurethane-based polymer is, for example, by reacting polyoxyethylene polyoxypropylene glycol and a diisocyanate compound in the presence of a urethane reaction catalyst.

<B-1-1. Water phase component>
The aqueous phase component can be any aqueous fluid that is substantially immiscible with the continuous oil phase component. From the viewpoint of ease of handling and low cost, water such as ion-exchanged water is preferable.

  Any appropriate additive may be contained in the aqueous phase component as long as the effects of the present invention are not impaired. Examples of such additives include polymerization initiators and water-soluble salts. The water-soluble salt can be an effective additive for further stabilizing the W / O emulsion. Examples of such water-soluble salts include sodium carbonate, calcium carbonate, potassium carbonate, sodium phosphate, calcium phosphate, potassium phosphate, sodium chloride, potassium chloride and the like. Only one kind of such an additive may be contained, or two or more kinds thereof may be contained. The additive that can be contained in the aqueous phase component may be only one kind or two or more kinds.

<B-1-2. Continuous oil phase component>
The continuous oil phase component preferably contains a hydrophilic polyurethane polymer and an ethylenically unsaturated monomer. The content ratio of the hydrophilic polyurethane polymer and the ethylenically unsaturated monomer in the continuous oil phase component can take any appropriate content ratio as long as the effects of the present invention are not impaired.

  The hydrophilic polyurethane-based polymer depends on the polyoxyethylene ratio in the polyoxyethylene polyoxypropylene glycol unit constituting the hydrophilic polyurethane-based polymer or the amount of the aqueous phase component to be blended. The hydrophilic polyurethane polymer is in the range of 10 to 30 parts by weight with respect to 70 to 90 parts by weight of the ethylenically unsaturated monomer, and more preferably hydrophilic to 75 to 90 parts by weight of the ethylenically unsaturated monomer. The polyurethane polymer is in the range of 10 to 25 parts by weight. Further, for example, the hydrophilic polyurethane polymer is preferably in the range of 1 to 30 parts by weight, more preferably 1 to 25 parts by weight of the hydrophilic polyurethane polymer with respect to 100 parts by weight of the aqueous phase component. It is a range. If the content ratio of the hydrophilic polyurethane polymer is within the above range, the effects of the present invention can be sufficiently exhibited.

(B-1-2-1. Hydrophilic polyurethane polymer)
The hydrophilic polyurethane-based polymer preferably contains a polyoxyethylene polyoxypropylene unit derived from polyoxyethylene polyoxypropylene glycol, and 5 wt% to 25 wt% in the polyoxyethylene polyoxypropylene unit is polyoxyethylene. Ethylene.

  The content ratio of polyoxyethylene in the polyoxyethylene polyoxypropylene unit is preferably 5% by weight to 25% by weight as described above, and is more preferably 10% by weight as the lower limit, and the upper limit. More preferably, it is 25% by weight, and more preferably 20% by weight. The polyoxyethylene in the polyoxyethylene polyoxypropylene unit exhibits an effect of stably dispersing the aqueous phase component in the continuous oil phase component. When the content of polyoxyethylene in the polyoxyethylene polyoxypropylene unit is less than 5% by weight, it may be difficult to stably disperse the water phase component in the continuous oil phase component. If the polyoxyethylene content in the polyoxyethylene polyoxypropylene unit exceeds 25% by weight, there is a risk of phase inversion from a W / O type emulsion to an O / W type (oil-in-water type) emulsion as it approaches the HIPE condition. There is.

  A conventional hydrophilic polyurethane polymer can be obtained by reacting a diisocyanate compound with a hydrophobic long-chain diol, polyoxyethylene glycol and derivatives thereof, and a low molecular active hydrogen compound (chain extender). Since the number of polyoxyethylene groups contained in the hydrophilic polyurethane polymer obtained in 1) is uneven, the emulsion stability of such a W / O emulsion containing such a hydrophilic polyurethane polymer may be reduced. There is. On the other hand, the hydrophilic polyurethane-based polymer contained in the continuous oil phase component of the W / O emulsion that can be used to obtain the liquid-absorbing continuous porous body of the present invention has the above-mentioned characteristic structure. When included in the continuous oil phase component of the W / O type emulsion, excellent emulsifying properties and excellent stationary storage stability can be expressed without positively adding an emulsifier or the like.

  The hydrophilic polyurethane-based polymer is preferably obtained by reacting polyoxyethylene polyoxypropylene glycol and a diisocyanate compound. In this case, the ratio between the polyoxyethylene polyoxypropylene glycol and the diisocyanate compound is NCO / OH (equivalent ratio), and the lower limit is preferably 1, more preferably 1.2, and still more preferably 1. .4, particularly preferably 1.6, and the upper limit is preferably 3, more preferably 2.5, and even more preferably 2. When NCO / OH (equivalent ratio) is less than 1, a gelled product may be easily formed when a hydrophilic polyurethane polymer is produced. When the NCO / OH (equivalent ratio) exceeds 3, the residual diisocyanate compound increases, and the W / O emulsion that can be used to obtain the liquid-absorbing continuous porous body of the present invention may become unstable. is there.

  As polyoxyethylene polyoxypropylene glycol, for example, polyether polyol (ADEKA (registered trademark) Pluronic L-31, L-61, L-71, L-101, L-121, L-42 manufactured by ADEKA Corporation) , L-62, L-72, L-122, 25R-1, 25R-2, 17R-2) and polyoxyethylene polyoxypropylene glycol (Pronon (registered trademark) 052, 102, manufactured by NOF Corporation. 202). As for polyoxyethylene polyoxypropylene glycol, only 1 type may be used and 2 or more types may be used together.

  Examples of the diisocyanate compound include aromatic, aliphatic, and alicyclic diisocyanates, dimers and trimers of these diisocyanates, polyphenylmethane polyisocyanate, and the like. Aromatic, aliphatic, and alicyclic diisocyanates include tolylene diisocyanate, diphenylmethane diisocyanate, hexamethylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate. 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, butane-1,4-diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, cyclohexane-1,4 -Diisocyanate, dicyclohexylmethane-4,4-diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, methyl Cyclohexane diisocyanate, m- tetramethylxylylene diisocyanate. Examples of the diisocyanate trimer include isocyanurate type, burette type, and allophanate type. Only 1 type may be used for a diisocyanate compound and it may use 2 or more types together.

  The diisocyanate compound may be selected as appropriate from the viewpoint of urethane reactivity with the polyol and the like, as well as the type and combination thereof. From the viewpoint of rapid urethane reactivity with polyol and suppression of reaction with water, it is preferable to use alicyclic diisocyanate.

  The weight average molecular weight of the hydrophilic polyurethane polymer is preferably 5000 as a lower limit, more preferably 7000, still more preferably 8000, particularly preferably 10,000, and preferably 50,000 as an upper limit. More preferably, it is 40000, more preferably 30000, and particularly preferably 20000.

  The hydrophilic polyurethane polymer may have an unsaturated double bond capable of radical polymerization at the terminal. By having an unsaturated double bond capable of radical polymerization at the terminal of the hydrophilic polyurethane-based polymer, the effects of the present invention can be further exhibited.

(B-1-2-2. Ethylenically unsaturated monomer)
As the ethylenically unsaturated monomer, any appropriate monomer can be adopted as long as it is a monomer having an ethylenically unsaturated double bond. Only one type of ethylenically unsaturated monomer may be used, or two or more types may be used.

  The ethylenically unsaturated monomer preferably comprises a (meth) acrylic ester. The content ratio of the (meth) acrylic acid ester in the ethylenically unsaturated monomer is preferably 80% by weight, more preferably 85% by weight as the lower limit, and preferably 100% by weight as the upper limit. More preferably, it is 98% by weight. Only one (meth) acrylic acid ester may be used, or two or more may be used.

  The (meth) acrylic acid ester is preferably an alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms (a concept including a cycloalkyl group, an alkyl (cycloalkyl) group, and a (cycloalkyl) alkyl group). It is. Preferably the carbon number of the said alkyl group is 4-18. In addition, (meth) acryl means acryl and / or methacryl, and (meth) acrylate means acrylate and / or methacrylate.

  Examples of the alkyl (meth) acrylate having an alkyl group having 1 to 20 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, and s-butyl. (Meth) acrylate, t-butyl (meth) acrylate, isobutyl (meth) acrylate, n-pentyl (meth) acrylate, isopentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, isoamyl (meth) Acrylate, 2-ethylhexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, n-nonyl (meth) acrylate, isononyl (meth) acrylate, n-decyl (meth) acrylate, isode Ru (meth) acrylate, n-dodecyl (meth) acrylate, isomyristyl (meth) acrylate, n-tridecyl (meth) acrylate, n-tetradecyl (meth) acrylate, stearyl (meth) acrylate, lauryl (meth) acrylate, pentadecyl (Meth) acrylate, hexadecyl (meth) acrylate, heptadecyl (meth) acrylate, octadecyl (meth) acrylate, nonadecyl (meth) acrylate, eicosyl (meth) acrylate, isostearyl (meth) acrylate, isobornyl (meth) acrylate, etc. It is done. Among these, n-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isobornyl (meth) acrylate are preferable. Only 1 type may be sufficient as the alkyl (meth) acrylate which has a C1-C20 alkyl group, and 2 or more types may be sufficient as it.

  The ethylenically unsaturated monomer preferably further comprises a polar monomer copolymerizable with the (meth) acrylic acid ester. The content of the polar monomer in the ethylenically unsaturated monomer is preferably 0% by weight, more preferably 2% by weight as the lower limit, and preferably 20% by weight, more preferably as the upper limit. 15% by weight. Only one type of polar monomer may be used, or two or more types may be used.

  Examples of polar monomers include (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, ω-carboxy-polycaprolactone monoacrylate, phthalic acid monohydroxyethyl acrylate, itaconic acid, maleic acid, fumaric acid Carboxyl group-containing monomers such as acid and crotonic acid; acid anhydride monomers such as maleic anhydride and itaconic anhydride; 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and (meth) acrylic acid 4-hydroxybutyl, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydecyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, (4-hydroxymethyl Shi And hydroxyl group-containing monomers such as chlorohexyl) methyl (meth) acrylate; amide group-containing monomers such as N, N-dimethyl (meth) acrylamide and N, N-diethyl (meth) acrylamide;

(B-1-2-3. Polymerization initiator)
The continuous oil phase component preferably contains a polymerization initiator.

  Examples of the polymerization initiator include radical polymerization initiators and redox polymerization initiators. Examples of the radical polymerization initiator include a thermal polymerization initiator and a photopolymerization initiator.

  Examples of the thermal polymerization initiator include azo compounds, peroxides, peroxycarbonic acid, peroxycarboxylic acid, potassium persulfate, t-butylperoxyisobutyrate, and 2,2′-azobisisobutyronitrile. .

  Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone (for example, Ciba Japan, trade name: Darocur-2959), α-hydroxy- α, α'-dimethylacetophenone (for example, Ciba Japan, trade name: Darocur-1173), methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone (for example, Ciba Japan, trade name) Acetophenone photopolymerization initiators such as Irgacure-651) and 2-hydroxy-2-cyclohexylacetophenone (for example, Ciba Japan, trade name; Irgacure-184); Ketal photopolymerization initiator such as benzyldimethyl ketal Agents; Other halogenated ketones; Acylphosphine oxides (As an example, Ciba Japan Co., Ltd., trade name: Irgacure -819); and the like.

  The polymerization initiator may contain only 1 type and may contain 2 or more types.

  The content of the polymerization initiator is preferably 0.05% by weight, more preferably 0.1% by weight, more preferably 0.1%, and preferably 5.0% as a lower limit with respect to the entire continuous oil phase component. % By weight, more preferably 1.0% by weight. When the content of the polymerization initiator is less than 0.05% by weight based on the entire continuous oil phase component, the amount of unreacted monomer components increases, and the amount of residual monomer in the resulting liquid absorbent continuous porous body increases. There is a risk. When the content of the polymerization initiator exceeds 5.0% by weight with respect to the entire continuous oil phase component, the mechanical properties of the obtained liquid-absorbing continuous porous body may be lowered.

  Note that the amount of radicals generated by the photopolymerization initiator varies depending on the type and intensity of light to be irradiated, the irradiation time, the amount of dissolved oxygen in the monomer and solvent mixture, and the like. And when there is much dissolved oxygen, the radical generation amount by a photoinitiator is suppressed, superposition | polymerization does not fully advance and an unreacted substance may increase. Therefore, it is preferable to blow an inert gas such as nitrogen into the reaction system and replace oxygen with the inert gas before the light irradiation.

(B-1-2-4. Crosslinking agent)
The continuous oil phase component preferably includes a cross-linking agent.

  Crosslinking agents are typically used to link polymer chains together to build a more three-dimensional molecular structure. The selection of the type and content of the cross-linking agent depends on the structural properties, mechanical properties, and fluid treatment properties desired for the resulting liquid absorbent continuous porous body. The selection of the specific type and content of the cross-linking agent is important in realizing a desirable combination of structural characteristics, mechanical characteristics, and fluid treatment characteristics of the liquid-absorbing continuous porous body.

  In producing the liquid-absorbing continuous porous material of the present invention, preferably, at least two kinds of crosslinking agents having different weight average molecular weights are used as the crosslinking agent.

  In producing the liquid-absorbing continuous porous material of the present invention, more preferably, as a crosslinking agent, “polyfunctional (meth) acrylate having a weight average molecular weight of 800 or more, polyfunctional (meth) acrylamide, and polymerization reactivity” “One or more selected from oligomers” and “one or more selected from polyfunctional (meth) acrylates and polyfunctional (meth) acrylamides having a weight average molecular weight of 500 or less” are used in combination. Here, the polyfunctional (meth) acrylate is specifically a polyfunctional (meth) acrylate having at least two ethylenically unsaturated groups in one molecule, and the polyfunctional (meth) acrylamide is Specifically, it is polyfunctional (meth) acrylamide having at least two ethylenically unsaturated groups in one molecule.

  Examples of the polyfunctional (meth) acrylate include diacrylates, triacrylates, tetraacrylates, dimethacrylates, trimethacrylates, and tetramethacrylates.

  Examples of the polyfunctional (meth) acrylamide include diacrylamides, triacrylamides, tetraacrylamides, dimethacrylamides, trimethacrylamides, tetramethacrylamides and the like.

  The polyfunctional (meth) acrylate can be derived from, for example, diols, triols, tetraols, bisphenol A and the like. Specifically, for example, 1,10-decanediol, 1,8-octanediol, 1,6 hexanediol, 1,4-butanediol, 1,3-butanediol, 1,4 butane-2-enediol , Ethylene glycol, diethylene glycol, trimethylolpropane, pentaerythritol, hydroquinone, catechol, resorcinol, triethylene glycol, polyethylene glycol, sorbitol, polypropylene glycol, polytetramethylene glycol, modified bisphenol A propylene oxide, and the like.

  The polyfunctional (meth) acrylamide can be derived from, for example, corresponding diamines, triamines, tetraamines and the like.

  Examples of the polymerization reactive oligomer include urethane (meth) acrylate, epoxy (meth) acrylate, copolyester (meth) acrylate, oligomer di (meth) acrylate and the like. Preferably, it is hydrophobic urethane (meth) acrylate.

  The weight average molecular weight of the polymerization reactive oligomer is preferably 1500 or more, more preferably 2000 or more. Although the upper limit of the weight average molecular weight of a polymerization reactive oligomer is not specifically limited, For example, Preferably it is 10,000 or less.

  As the cross-linking agent, “one or more selected from polyfunctional (meth) acrylates having a weight average molecular weight of 800 or more, polyfunctional (meth) acrylamides, and polymerization reactive oligomers” and “a weight average molecular weight of 500 or less. When using together with “one or more selected from functional (meth) acrylate and polyfunctional (meth) acrylamide” ”,“ polyfunctional (meth) acrylate having a weight average molecular weight of 800 or more, polyfunctional (meth) acrylamide, and polymerization ” The amount of “one or more selected from reactive oligomers” is preferably 40% by weight as a lower limit with respect to the total amount of the hydrophilic polyurethane polymer and the ethylenically unsaturated monomer in the continuous oil phase component. The upper limit is preferably 100% by weight, and more preferably 80% by weight. The amount of use of “one or more selected from a polyfunctional (meth) acrylate having a weight average molecular weight of 800 or more, a polyfunctional (meth) acrylamide, and a polymerization reactive oligomer” is a hydrophilic polyurethane-based heavy in the continuous oil phase component If it is less than 40% by weight based on the total amount of the coalesced and ethylenically unsaturated monomer, the cohesive strength of the resulting liquid-absorbing continuous porous body may be reduced, making it difficult to achieve both toughness and flexibility. There is a risk. The amount of use of “one or more selected from a polyfunctional (meth) acrylate having a weight average molecular weight of 800 or more, a polyfunctional (meth) acrylamide, and a polymerization reactive oligomer” is a hydrophilic polyurethane-based heavy in the continuous oil phase component When the amount exceeds 100% by weight with respect to the total amount of the coalesced and ethylenically unsaturated monomer, the emulsion stability of the W / O emulsion is lowered, and the desired liquid-absorbing continuous porous body may not be obtained. .

  As the cross-linking agent, “one or more selected from polyfunctional (meth) acrylates having a weight average molecular weight of 800 or more, polyfunctional (meth) acrylamides, and polymerization reactive oligomers” and “a weight average molecular weight of 500 or less. When using together with “one or more selected from functional (meth) acrylate and polyfunctional (meth) acrylamide” ”,“ selected from polyfunctional (meth) acrylate and polyfunctional (meth) acrylamide having a weight average molecular weight of 500 or less ” The amount of “one or more” used is preferably 1% by weight, more preferably 5% as a lower limit with respect to the total amount of the hydrophilic polyurethane polymer and the ethylenically unsaturated monomer in the continuous oil phase component. The upper limit is preferably 30% by weight, and more preferably 20% by weight. Use amount of “one or more selected from polyfunctional (meth) acrylate having a weight average molecular weight of 500 or less and polyfunctional (meth) acrylamide” is a hydrophilic polyurethane polymer and ethylenic unsaturated in a continuous oil phase component When the amount is less than 1% by weight based on the total amount of monomers, the heat resistance is lowered, and the cell structure may be crushed by contraction in the step (IV) of dehydrating the water-containing polymer. Use amount of “one or more selected from polyfunctional (meth) acrylate having a weight average molecular weight of 500 or less and polyfunctional (meth) acrylamide” is a hydrophilic polyurethane polymer and ethylenic unsaturated in a continuous oil phase component When it exceeds 30% by weight with respect to the total amount of the monomers, the toughness of the obtained liquid-absorbing continuous porous body is lowered and there is a possibility that brittleness is exhibited.

  The crosslinking agent may contain only 1 type and may contain 2 or more types.

(B-1-2-5. Other components in the continuous oil phase component)
The continuous oil phase component may contain any appropriate other component as long as the effects of the present invention are not impaired. Typically, such other components preferably include a catalyst, an antioxidant, an organic solvent, and the like. Such other components may be only one type or two or more types.

  Examples of the catalyst include a urethane reaction catalyst. Any appropriate catalyst can be adopted as the urethane reaction catalyst. Specific examples include dibutyltin dilaurate.

  Arbitrary appropriate content rates can be employ | adopted for the content rate of a catalyst according to the target catalytic reaction.

  The catalyst may contain only 1 type and may contain 2 or more types.

  Examples of the antioxidant include a phenol-based antioxidant, a thioether-based antioxidant, and a phosphorus-based antioxidant.

  Arbitrary appropriate content rates can be employ | adopted for the content rate of antioxidant in the range which does not impair the effect of this invention.

  Antioxidant may contain only 1 type and may contain 2 or more types.

  Any appropriate organic solvent can be adopted as the organic solvent as long as the effects of the present invention are not impaired.

  Arbitrary appropriate content rates can be employ | adopted for the content rate of an organic solvent in the range which does not impair the effect of this invention.

  The organic solvent may contain only 1 type and may contain 2 or more types.

<< B-2. Step of shaping W / O type emulsion (II) >>
In the step (II), any appropriate shaping method can be adopted as a method for shaping the W / O type emulsion. For example, there is a method in which a W / O emulsion is continuously supplied onto a traveling belt and shaped into a smooth sheet on the belt. Moreover, the method of apply | coating to one surface of a thermoplastic resin film, and shaping is mentioned.

  In the step (II), as a method of shaping the W / O type emulsion, when adopting a method of coating and shaping on one surface of a thermoplastic resin film, as a method of coating, for example, a roll coater, Examples include a method using a die coater, a knife coater, or the like.

<< B-3. Step of polymerizing shaped W / O emulsion (III) >>
In the step (III), any appropriate polymerization method can be adopted as a method for polymerizing the shaped W / O emulsion. For example, the belt surface of a belt conveyor is heated by a heating device, and a W / O type emulsion is continuously supplied onto a traveling belt and shaped into a smooth sheet on the belt by heating. A W / O emulsion is continuously supplied onto the running belt, with a method of polymerization and a structure in which the belt surface of the belt conveyor is heated by irradiation of active energy rays, and a smooth sheet is formed on the belt. The method of superposing | polymerizing by irradiation of an active energy ray is mentioned, shaping.

  In the case of polymerization by heating, the polymerization temperature (heating temperature) is preferably 23 ° C., more preferably 50 ° C., still more preferably 70 ° C., particularly preferably 80 ° C. as the lower limit. The upper limit is preferably 90 ° C, and is preferably 150 ° C, more preferably 130 ° C, and even more preferably 110 ° C. When the polymerization temperature is less than 23 ° C., the polymerization takes a long time, and industrial productivity may be reduced. When the polymerization temperature exceeds 150 ° C., the pore size of the obtained liquid-absorbing continuous porous body may be nonuniform, and the strength of the liquid-absorbing continuous porous body may be reduced. The polymerization temperature need not be constant. For example, the polymerization temperature may be varied in two stages or multiple stages during the polymerization.

  In the case of polymerization by irradiation with active energy rays, examples of the active energy rays include ultraviolet rays, visible rays, and electron beams. The active energy ray is preferably ultraviolet light or visible light, and more preferably visible to ultraviolet light having a wavelength of 200 nm to 800 nm. Since the W / O type emulsion has a strong tendency to scatter light, it is possible to penetrate the W / O type emulsion by using visible to ultraviolet light having a wavelength of 200 nm to 800 nm. Moreover, the photoinitiator which can be activated with a wavelength of 200 nm-800 nm is easy to obtain, and a light source is easy to obtain.

  The wavelength of the active energy ray is preferably 200 nm, more preferably 300 nm as the lower limit value, and preferably 800 nm, more preferably 450 nm as the upper limit value.

  As a typical apparatus used for irradiation of active energy rays, for example, an ultraviolet lamp capable of performing ultraviolet irradiation includes an apparatus having a spectral distribution in a wavelength region of 300 to 400 nm. , Black light (trade name manufactured by Toshiba Lighting & Technology Co., Ltd.), metal halide lamp and the like.

  The illuminance at the time of irradiation with active energy rays can be set to any appropriate illuminance by adjusting the distance from the irradiation device to the irradiation object and the voltage. For example, by the method disclosed in Japanese Patent Application Laid-Open No. 2003-13015, the ultraviolet irradiation in each step is performed in a plurality of stages, thereby making it possible to precisely adjust the adhesive performance.

  In order to prevent the adverse effect of oxygen having an inhibitory action on the ultraviolet rays, for example, a W / O emulsion is applied to one surface of a substrate such as a thermoplastic resin film and then shaped under an inert gas atmosphere. UV rays such as polyethylene terephthalate coated with a release agent such as silicone after passing through a W / O emulsion on one surface of a substrate such as a thermoplastic resin film and shaping, but blocking oxygen It is preferable to carry out by covering the film.

  As the thermoplastic resin film, any appropriate thermoplastic resin film can be adopted as long as it can be formed by coating a W / O emulsion on one surface. Examples of the thermoplastic resin film include plastic films and sheets such as polyester, olefin resin, and polyvinyl chloride.

  The inert gas atmosphere refers to an atmosphere in which oxygen in the light irradiation zone is replaced with an inert gas. Therefore, in the inert gas atmosphere, it is necessary that oxygen is not present as much as possible, and the oxygen concentration is preferably 5000 ppm or less.

<< B-4. Step of dehydrating the obtained water-containing polymer (IV) >>
In step (IV), the obtained water-containing polymer is dehydrated. In the water-containing polymer obtained in step (III), the aqueous phase component is present in a dispersed state. By removing the aqueous phase component by dehydration and drying, a porous body contained in the liquid-absorbing continuous porous body of the present invention is obtained. The obtained porous body can directly become the liquid-absorbing continuous porous body of the present invention. Further, as described later, the liquid-absorbing continuous porous body of the present invention can be obtained by combining with a base material.

  Arbitrary appropriate drying methods can be employ | adopted as a dehydration method in process (IV). Examples of such a drying method include vacuum drying, freeze drying, press drying, microwave drying, drying in a heat oven, drying with infrared rays, or a combination of these techniques.

<< B-5. When the liquid-absorbing continuous porous material of the present invention contains a base material >>
When the liquid-absorbing continuous porous material of the present invention contains a substrate, as one of the preferred embodiments of the method for producing the liquid-absorbing continuous porous material of the present invention, a W / O emulsion is applied to one surface of the substrate. W / O type emulsion by heating or irradiation with active energy rays in an inert gas atmosphere or in a state where oxygen is blocked by coating with a UV transparent film coated with a release agent such as silicone Is obtained as a water-containing polymer, and the resulting water-containing polymer is dehydrated to form a liquid-absorbing continuous porous material having a substrate / porous layer laminated structure.

  As another preferred embodiment of the method for producing the liquid-absorbing continuous porous body of the present invention, a W / O emulsion is applied to one surface of an ultraviolet transmissive film coated with a release agent such as silicone. A sheet is prepared, a substrate is laminated on the coated surface of one of the two W / O emulsion coated sheets, and another W / O emulsion is formed on the other surface of the laminated substrate. In a state where the coated surfaces of the coated sheets are laminated so as to match with each other, by heating or irradiating active energy rays, the W / O emulsion is polymerized to form a hydrous polymer, and the obtained hydrous polymer is dehydrated. And a liquid-absorbing continuous porous body having a laminated structure of porous layer / base material / porous layer.

  Examples of the method of coating the W / O type emulsion on one side of the base material or one surface of the ultraviolet ray transmissive film coated with a release agent such as silicone include a roll coater, a die coater, and a knife coater.

  Hereinafter, although the present invention is explained based on an example, the present invention is not limited to these. The normal temperature means 23 ° C.

(Molecular weight measurement)
The weight average molecular weight was determined by GPC (gel permeation chromatography).
Equipment: “HLC-8020” manufactured by Tosoh Corporation
Column: “TSKgel GMH _HR- H (20)” manufactured by Tosoh Corporation
Solvent: Tetrahydrofuran Standard: Polystyrene

(Measurement of average pore diameter)
The obtained porous body was cut in the thickness direction with a microtome cutter and used as a measurement sample. The cut surface of the sample for measurement was photographed with a scanning electron microscope (Hitachi, S-3400N) at 800 to 5000 times. Using the photographed image, measure the pore diameter of an arbitrary range of spherical bubbles, the diameter of a through-hole penetrating between the spherical bubbles of an arbitrary range, and the pore diameter of the surface opening of an arbitrary range. The average hole diameter, the average hole diameter of the through holes, and the average hole diameter of the surface openings were calculated.

(Measurement of liquid absorption)
The obtained porous body was cut into 25 mm × 25 mm to obtain test pieces. The weight of the test piece (initial weight: W0 (g)) was measured in advance. The test piece was immersed in an amount of liquid sufficient to immerse the test piece for 30 minutes, 1 hour, or 24 hours. After immersion, the test piece was taken out of the liquid and left on the waste cloth at room temperature for 1 minute. After standing for 1 minute, the weight of the test piece (weight of the absorbed porous body: W1 (g)) was measured again. The liquid absorption rate was calculated based on the following formula.
Liquid absorption rate (% by weight) = [(W1-W0) / W0] × 100

(Measurement of dimensional change after liquid absorption (immersion test))
After the liquid absorption (immersion test), the end length of the test piece in which the liquid was absorbed was measured, and the dimensional change rate after the liquid absorption (immersion test) was calculated based on the following formula. The end length of the test piece before liquid absorption (immersion test) was L1 (mm), and the end length of the test piece after liquid absorption (immersion test) was L2 (mm).
Dimensional change rate after liquid absorption (immersion test) (%) = [(L2-L1) / L1] × 100

(Re-immersion test)
The obtained porous body was cut into 25 mm × 25 mm to obtain test pieces. The weight of the test piece (initial weight: W0 (g)) was measured in advance. The test piece was immersed for 24 hours in an amount of liquid sufficient to immerse the test piece. After immersion, the test piece was taken out of the liquid and left on the waste cloth at room temperature for 1 minute. After standing for 1 minute, the weight of the test piece (weight of the absorbed porous body: W1 (g)) was measured again. Here, the liquid absorption rate was calculated based on the above formula (primary immersion test).
Subsequently, the test piece for which the liquid absorption rate measurement was completed was immersed in water for 1 hour, then stored in an oven at 130 ° C. for 2 hours, and the liquid absorbed in the porous body was removed by heating and drying. After a storage treatment in an oven at 125 ° C. for 22 hours, the liquid absorption rate was measured again according to the method for measuring the liquid absorption rate (re-immersion test).

(Measurement of heating dimensional change rate)
The dimensional change in heating of the porous body was measured based on the dimensional stability evaluation at high temperature of JIS-K-6767. That is, the obtained porous body was cut into a size of 100 mm × 100 mm to obtain a test piece, which was stored in an oven at 125 ° C. for 22 hours, and then conformed to the dimensional stability evaluation at high temperature of JIS-K-6767. The dimensional change rate before and after the heat storage treatment was determined.

(Density measurement)
Five pieces of the obtained porous body were cut into a size of 100 mm × 100 mm to form test pieces, and the apparent density was determined by dividing the weight by the volume. The average value of the apparent density obtained was taken as the density of the porous body.

(Measurement of bubble rate)
Only the oil phase component at the time of producing the emulsion was polymerized, and the obtained polymer sheet was cut into five pieces of 100 mm × 100 mm to obtain test pieces, and the apparent density was obtained by dividing the weight by the volume. The average value of the apparent density obtained was taken as the density of the resin component constituting the porous body. The cell ratio of the porous body was calculated by the following formula using the relative density obtained by dividing the density of the porous body by the density of the resin component.
Bubble ratio = (1−relative density) × 100

[Production Example 1]: Preparation of mixed syrup 1 In a reaction vessel equipped with a condenser, a thermometer, and a stirrer, 2-ethylhexyl acrylate (manufactured by Toagosei Co., Ltd., hereinafter "2EHA") as an ethylenically unsaturated monomer A monomer solution consisting of 173.2 parts by weight, and 100 parts by weight of Adeka (registered trademark) Pluronic L-62 (molecular weight 2500, manufactured by ADEKA Corporation, polyether polyol) as polyoxyethylene polyoxypropylene glycol, As a urethane reaction catalyst, 0.014 part by weight of dibutyltin dilaurate (manufactured by Kishida Chemical Co., Ltd., hereinafter abbreviated as “DBTL”) is added and stirred, and hydrogenated xylylene diisocyanate (manufactured by Takeda Pharmaceutical Co., Ltd., Takenate). 600, hereinafter abbreviated as “HXDI”) 12.4 parts by weight were added dropwise and reacted at 65 ° C. for 4 hours. Let In addition, the usage-amount of the polyisocyanate component and the polyol component was NCO / OH (equivalent ratio) = 1.6. Thereafter, 5.6 parts by weight of 2-hydroxyethyl acrylate (manufactured by Kishida Chemical Co., Ltd., hereinafter abbreviated as “HEA”) is dropped and reacted at 65 ° C. for 2 hours, and a hydrophilic polyurethane system having acryloyl groups at both ends. A polymer / ethylenically unsaturated monomer mixed syrup was obtained. The weight average molecular weight of the obtained hydrophilic polyurethane polymer was 15,000. 25 parts by weight of 2EHA, 56 parts by weight of n-butyl acrylate (manufactured by Toa Gosei Co., Ltd., hereinafter abbreviated as “BA”) per 100 parts by weight of the obtained hydrophilic polyurethane polymer / ethylenically unsaturated monomer mixed syrup, 17.9 parts by weight of isobornyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd., hereinafter referred to as “IBXA”) and 10.7 parts by weight of acrylic acid (manufactured by Toagosei Co., Ltd., hereinafter referred to as “AA”) as a polar monomer In addition, a hydrophilic polyurethane polymer / ethylenically unsaturated monomer mixed syrup 1 was obtained.

[Example 1]: Production of test piece 1 To 100 parts by weight of the hydrophilic polyurethane polymer / ethylenically unsaturated monomer mixed syrup 1 obtained in Production Example 1, 1,6-hexanediol diacrylate (Shin Nakamura) Chemical Industry Co., Ltd., trade name “NK Ester A-HD-N”) (molecular weight 226) 11.9 parts by weight, as reactive oligomer, polytetramethylene glycol (hereinafter abbreviated as “PTMG”) and isophorone diisocyanate (hereinafter referred to as “PTMG”) And urethane acrylate (hereinafter abbreviated as “UA”) having both ends of a polyurethane synthesized from HEIP treated with HEA (molecular weight 3720) 47.7. Parts by weight, diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (manufactured by BASF, trade name “Lucirin TP” O ") 0.41 part by weight and 0.69 parts by weight of a hindered phenolic antioxidant (Ciba Japan Co., Ltd., trade name" Irganox 1010 ") were mixed uniformly to obtain a continuous oil phase component (hereinafter referred to as" oil "). Referred to as “phase”). On the other hand, 300 parts by weight of ion-exchanged water as an aqueous phase component (hereinafter referred to as “aqueous phase”) with respect to 100 parts by weight of the oil phase is continuously introduced into a stirring mixer that is an emulsifier charged with the oil phase at room temperature. Were added dropwise to prepare a stable W / O emulsion. The weight ratio of the water phase to the oil phase was 75/25.
The obtained W / O emulsion was stored at room temperature for 1 hour, and then applied onto a substrate that had been subjected to a release treatment so that the thickness after light irradiation was 1 mm, and was continuously molded. Further, a polyethylene terephthalate film having a thickness of 38 μm and subjected to a release treatment was placed thereon. This sheet was irradiated with ultraviolet light having a light illuminance of 5 mW / cm ² (measured with Topcon UVR-T1 having a peak sensitivity maximum wave of 350 nm) using black light (15 W / cm) to obtain a highly hydrous crosslinked polymer having a thickness of 1 mm. . Next, the top film was peeled off, and the high water content crosslinked polymer was heated at 130 ° C. for 20 minutes to obtain a liquid-absorbing continuous porous body (1) having a thickness of about 1 mm. This was designated as test piece 1.
A photograph of a surface / cross-sectional SEM photograph obtained by obliquely photographing the obtained liquid-absorbing continuous porous body (1) is shown in FIG.

[Example 2]: Production of test piece 2 In the same manner as in Example 1, a stable W / O emulsion was prepared.
The W / O type emulsion, which was stored at room temperature for 30 minutes from the preparation, on the polyethylene terephthalate film (hereinafter referred to as “PET film”) having a thickness of 38 μm which was subjected to the release treatment, The film was applied so as to have a thickness of 150 μm and continuously formed into a sheet shape. Furthermore, a 70 μm thick polyester fiber laminate fabric (manufactured by JX Nippon Mining & Chemicals, Inc., trade name “MILIFE (registered trademark) TY0505FE”) in which polyester long fibers are vertically aligned and laminated is laminated thereon. In addition, a W / O type emulsion that has been separately stored at room temperature for 30 minutes after preparation is placed on a PET film having a thickness of 38 μm that has been subjected to a release treatment so that the thickness of the porous layer after light irradiation is 150 μm. A coated material was prepared, and the coated surface was covered with the polyester fiber laminated fabric. This sheet was irradiated with ultraviolet rays having a light illuminance of 5 mW / cm ² (measured with Topcon UVR-T1 having a peak sensitivity maximum wave of 350 nm) using black light (15 W / cm) to obtain a highly hydrous crosslinked polymer having a thickness of 300 μm. . Next, the upper film was peeled off, and the high water content crosslinked polymer was heated at 130 ° C. for 20 minutes to obtain a liquid-absorbing continuous porous material (2) having a thickness of about 300 μm. This was designated as test piece 2.

[Example 3]: Manufacture of test piece 3 In Example 1, the same operation as in Example 1 was performed except that 186 parts by weight of ion-exchanged water was continuously added dropwise as an aqueous phase at room temperature. A W / O type emulsion was prepared. The weight ratio of the water phase to the oil phase was 65/35.
Next, the obtained W / O emulsion was subjected to the same operation as in Example 2 to obtain a liquid-absorbing continuous porous body (3) having a thickness of about 300 μm. This was designated as test piece 3.

[Example 4]: Production of test piece 4 In Example 1, the same operation as in Example 1 was carried out except that 566.7 parts by weight of ion-exchanged water was continuously added dropwise at room temperature as the aqueous phase. A stable W / O emulsion was prepared. The weight ratio of the water phase to the oil phase was 85/15.
Next, the obtained W / O emulsion was subjected to the same operation as in Example 2 to obtain a liquid-absorbing continuous porous body (4) having a thickness of about 400 μm. This was designated as test piece 4.

Example 5
Test piece 1 was immersed in deionized water for 30 minutes, measured for liquid absorption rate (immersion time = 30 minutes) (primary immersion test), measured for dimensional change after liquid absorption (primary immersion test), absorbed The appearance after the liquid (primary immersion test) was observed.
Subsequently, the test piece 1 in which the ion-exchanged water after the primary immersion test was absorbed was immersed in the ion-exchanged water for 30 minutes, and the liquid absorption rate (immersion time = 30 minutes) was measured (secondary immersion test). The dimensional change after liquid absorption (secondary immersion test) was measured, and the appearance after liquid absorption (secondary immersion test) was observed.
The results are shown in Table 1.

Example 6
Test piece 1 was immersed in toluene for 30 minutes, measured for liquid absorption rate (immersion time = 30 minutes) (primary immersion test), measured for dimensional change after liquid absorption (primary immersion test), liquid absorption ( The appearance after the primary immersion test) was observed.
Then, about the test piece 1 in which the toluene after the primary immersion test was absorbed, the sample was immersed in toluene for 30 minutes, and the liquid absorption rate (immersion time = 30 minutes) was measured (secondary immersion test). The dimensional change rate after the secondary immersion test) was observed, and the appearance after the liquid absorption (secondary immersion test) was observed.
The results are shown in Table 1.

Example 7
Test piece 1 was immersed in deionized water for 30 minutes, measured for liquid absorption rate (immersion time = 30 minutes) (primary immersion test), measured for dimensional change after liquid absorption (primary immersion test), absorbed The appearance after the liquid (primary immersion test) was observed.
Subsequently, the test piece 1 in which the ion-exchanged water after the primary immersion test was absorbed was immersed in toluene for 30 minutes, and the liquid absorption rate (immersion time = 30 minutes) was measured (secondary immersion test). Measurement of the dimensional change rate after the liquid (secondary immersion test) and observation of the appearance after the liquid absorption (secondary immersion test) were performed.
Even though the test piece 1 in which the ion-exchanged water after the primary immersion test was absorbed was immersed in toluene for 30 minutes, no appearance of the ion-exchanged water being separated was observed.
The results are shown in Table 1.

Example 8
Using the test piece 2, a re-immersion test was performed for each of ethanol, hydrochloric acid (10% aqueous solution), hydrochloric acid (3% aqueous solution), and ion-exchanged water. The dimensional change rate after the primary immersion test was also measured.
The results are shown in Table 2.

Example 9
Using the test piece 3, a re-immersion test was performed for each of ethanol, hydrochloric acid (10% aqueous solution), hydrochloric acid (3% aqueous solution), and ion-exchanged water. The dimensional change rate after the primary immersion test was also measured.
The results are shown in Table 2.

Example 10
Using the test piece 4, a re-immersion test was performed for each of ethanol, hydrochloric acid (10% aqueous solution), hydrochloric acid (3% aqueous solution), and ion-exchanged water. The dimensional change rate after the primary immersion test was also measured.
The results are shown in Table 2.

[Comparative Example 1]
Using a commercially available urethane foam (“PORON (registered trademark)” manufactured by Roger Sinoac Co., Ltd.), a re-immersion test was conducted for each of ethanol, hydrochloric acid (10% aqueous solution), hydrochloric acid (3% aqueous solution), and ion-exchanged water. went. The dimensional change rate after the primary immersion test was also measured.
The results are shown in Table 2.

  The liquid-absorbing continuous porous body of the present invention can be preferably used for various liquid-absorbing members such as a liquid-absorbing material for waste liquid treatment.

DESCRIPTION OF SYMBOLS 100 Liquid-absorbing continuous porous body 10 Porous body 10a Porous body 10b Porous body 20 Base material 30 Release film

Claims (10)

Including a porous body having spherical bubbles,
The oil and moisture absorption rates are both 100% by weight or more,
Liquid-absorbing continuous porous body.   After absorbing the liquid L at a liquid absorption rate of A wt%, the liquid L absorbed by heating and drying is released, and then the liquid absorption rate is 0.9 A wt% when the liquid L is absorbed again. The liquid-absorbing continuous porous body according to claim 1, which is as described above.   The liquid-absorbing continuous porous body according to claim 1 or 2, wherein a dimensional change rate after oil absorption is 50% or less.   The liquid-absorbing continuous porous body according to any one of claims 1 to 3, wherein a dimensional change rate after water absorption is 10% or less.   The liquid-absorbing continuous porous body according to any one of claims 1 to 4, wherein a dimensional change rate when stored at 125 ° C for 22 hours is less than ± 5%.   The liquid-absorbing continuous porous body according to any one of claims 1 to 5, wherein the porous body contains a hydrophilic polyurethane-based polymer.   The liquid-absorbing continuous porous body according to any one of claims 1 to 6, wherein the spherical pores have an average pore diameter of less than 20 µm.   The liquid-absorbing continuous porous body according to any one of claims 1 to 7, wherein the porous body has an open cell structure having through holes between adjacent spherical bubbles.   The liquid-absorbing continuous porous body according to claim 8, wherein an average pore diameter of the through-holes is 5 µm or less. The liquid-absorbing continuous porous body according to any one of claims 1 to 9, wherein the density of the porous body is 0.15 to 0.5 g / cm ³ .