JP5818561B2 - Black foil adhesive and black adhesive sheet - Google Patents

Description

  The present invention relates to a black foil-like pressure-sensitive adhesive and a black pressure-sensitive adhesive sheet provided with the same.

  In recent years, a pressure-sensitive adhesive sheet having a black appearance may be required to impart concealability for design and functionality to the pressure-sensitive adhesive sheet.

  As means for imparting a black appearance to the pressure-sensitive adhesive sheet, there are means for making the base material black among the constituent parts of the pressure-sensitive adhesive sheet and means for making the pressure-sensitive adhesive layer black.

  As the former means for imparting a black appearance to the pressure-sensitive adhesive sheet, when the pressure-sensitive adhesive sheet is a single-sided pressure-sensitive adhesive sheet, a means for using a black base material or a base material with a black printed surface is used. Has been proposed. Further, when the pressure-sensitive adhesive sheet is a double-sided pressure-sensitive adhesive sheet composed of a core material and two pressure-sensitive adhesive layers arranged so as to sandwich the core material, means for blackening at least the surface of the core material has been proposed. (For example, Patent Document 1).

  As the latter means for imparting a black appearance to the pressure-sensitive adhesive sheet, Patent Document 2 discloses a pressure-sensitive adhesive sheet in which a black pressure-sensitive adhesive layer containing carbon black as a pigment is provided on one or both sides of a plastic film.

JP 2005-60435 A Japanese Patent No. 3879899

However, each of the above conventional techniques has the following problems.
First, a single-sided pressure-sensitive adhesive sheet having a black base material needs to be specially embedded or printed on the base material in order to obtain the black base material. Therefore, the production cost of the entire single-sided pressure-sensitive adhesive sheet increases.

  Since the double-sided pressure-sensitive adhesive sheet disclosed in Patent Document 1 has a three-layer structure of pressure-sensitive adhesive layer / black core material / pressure-sensitive adhesive layer, the double-sided pressure-sensitive adhesive sheet becomes thicker than a normal double-sided pressure-sensitive adhesive sheet comprising only the pressure-sensitive adhesive layer. . Therefore, it is difficult to design a thin black double-sided PSA sheet. Moreover, in order to obtain the double-sided adhesive sheet disclosed by patent document 1, it is necessary to apply an adhesive to both surfaces of a core material. For this reason, a manufacturing process (coating frequency) increases compared with the normal double-sided adhesive sheet which consists only of an adhesive layer. And it is necessary to prepare a black core material, and the production cost is high like the black base material in said single-sided adhesive sheet. For this reason, the double-sided pressure-sensitive adhesive sheet disclosed in Patent Document 1 has a significantly higher production cost than a normal double-sided pressure-sensitive adhesive sheet comprising only a pressure-sensitive adhesive layer.

  Since the pressure-sensitive adhesive sheet disclosed in Patent Document 2 has low dispersibility of the pigment (specifically, carbon black) contained in the pressure-sensitive adhesive layer, the surface state is poor due to non-uniform dispersion of the pigment (appearance defect, Adhesion failure) occurs.

  The present invention has been made in view of such a situation, and is a black foil-like pressure-sensitive adhesive that is excellent in design, optical characteristics, and adhesive strength, can be made into a thin film, and can be manufactured at low cost. And it aims at providing a black adhesive sheet.

  In order to achieve the above object, first, the present invention is a black foil-like pressure-sensitive adhesive containing an adhesive component, a black pigment, and a styrene-maleic acid resin, wherein the black foil-like pressure-sensitive adhesive is Provided is a black foil-like pressure-sensitive adhesive having a black pigment content of 2 to 6% by mass (Invention 1).

  In the black foil-like pressure-sensitive adhesive according to the above invention (Invention 1), the inclusion of the styrene-maleic acid resin makes it difficult for the black pigment to aggregate, and the black pigment can be uniformly dispersed. Further, since the foil-like pressure-sensitive adhesive itself is black, a conventional core material is not required. Therefore, the black foil-like pressure-sensitive adhesive is excellent in black appearance, optical properties and adhesive strength, can be thinned (for example, about 1 μm), and can be produced at low cost.

  The black foil-like pressure-sensitive adhesive according to the above invention (Invention 1) preferably has an adhesive strength to a polyethylene plate of 2 N / 25 mm or more (Invention 2).

  In the said invention (invention 1 and 2), it is preferable that content of the said styrene-maleic acid resin is 2.5-10 mass parts with respect to 1 mass part of said black pigments (invention 3).

  In the said invention (invention 1-3), it is preferable that the said adhesion component is bridge | crosslinked by the crosslinking agent (invention 4).

  In the said invention (invention 1-4), the thickness of the said black foil adhesive is 1-5 micrometers, The product xw of the said thickness (unit: micrometer) and content (unit: mass%) of the said black pigment. Is 5 μm · mass% or more and the total light transmittance is 70% or less (Invention 5), or the thickness of the black foil-like pressure-sensitive adhesive is 10 to 35 μm, and the thickness (unit: μm) and the above The product xw with the content (unit: mass%) of the black pigment is preferably 35 μm · mass% or more, and the total light transmittance is preferably 15% or less (Invention 6).

  In the said invention (invention 1-6), it is preferable that the average particle diameter of the said black pigment is 1-20 micrometers (invention 7).

  In the said invention (invention 1-7), it is preferable that the said black pigment is carbon black (invention 8).

  2ndly, this invention is a black adhesive sheet provided with the base material and the adhesive layer, Comprising: The said adhesive layer consists of the said black foil-like adhesive (Invention 1-8), It is characterized by the above-mentioned. A black pressure-sensitive adhesive sheet is provided (Invention 9). The “sheet” in the present invention includes the concept of a tape.

  Thirdly, the present invention is a black pressure-sensitive adhesive sheet comprising two release sheets and an adhesive layer sandwiched between the release sheets so as to be in contact with the release surfaces of the two release sheets. A black pressure-sensitive adhesive sheet is provided (Invention 10), wherein the agent layer is made of the black foil-like pressure-sensitive adhesive (Inventions 1 to 8).

  Since the black foil-like pressure-sensitive adhesive according to the present invention is less likely to cause aggregation of the black pigment by the styrene-maleic acid resin, the black pigment can be uniformly dispersed and no core material is required. Therefore, the black foil-like pressure-sensitive adhesive and the black pressure-sensitive adhesive sheet according to the present invention are excellent in black appearance, optical characteristics and adhesive strength, and can be thinned (for example, a black foil-like pressure-sensitive adhesive having a thickness of about 1 μm). Can be manufactured at cost.

It is a graph which shows the relationship between the total light transmittance and thickness-content product xw at the time of using carbon black as a black pigment. It is a graph which shows the relationship between thickness-content product xw and adhesive thickness at the time of using carbon black by different content as a black pigment. It is a graph which shows the relationship between thickness-content product xw and adhesive thickness at the time of using carbon black by different content as a black pigment. It is sectional drawing of the black adhesive sheet which concerns on the 1st Embodiment of this invention. It is sectional drawing of the black adhesive sheet which concerns on the 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described.
[Black foil adhesive]
1. Composition of Black Foil-like Adhesive The black foil-like adhesive according to one embodiment of the present invention contains an adhesive component, a black pigment, and a styrene-maleic acid resin. Hereinafter, these components and other components that may be contained as necessary will be described individually.

(1) Adhesive component The type of the adhesive component contained in the black foil-like pressure-sensitive adhesive according to this embodiment is not particularly limited, and can be appropriately selected according to the use of the black foil-like pressure-sensitive adhesive. Examples of the adhesive component include acrylic, rubber-based, silicone-based, polyurethane-based, and polyester-based adhesive components, among which acrylic adhesive components are preferable. The adhesive component may be any of an emulsion type, a solvent type or a solventless type, but a solvent type is preferable from the viewpoint of dispersibility of the black pigment. Furthermore, the adhesive component may be crosslinked by a crosslinking agent.

  Examples of the acrylic adhesive component include those containing a (meth) acrylic acid ester polymer. In this specification, (meth) acrylic acid ester means both acrylic acid ester and methacrylic acid ester. The same applies to other similar terms. (Cyclo) alkyl means a concept including both linear or branched alkyl as alkyl and cycloalkyl, and a polymer means a concept including a copolymer.

  The (meth) acrylic acid ester-based polymer is preferably a polymer having (meth) acrylic acid (cyclo) alkyl ester having at least 1 to 20 carbon atoms of (cyclo) alkyl group as a constituent monomer, and is desirable. According to the above, a monomer having a reactive functional group (reactive functional group-containing monomer), a monomer having a reactive catalytic functional group (reactive catalytic group-containing monomer), and the other having no reactive functional group and reactive catalytic functional group It may be a copolymer with at least one monomer selected from the group consisting of these monomers.

  Examples of the (cyclo) alkyl (meth) acrylic acid (cyclo) alkyl ester having 1 to 20 carbon atoms in the (cyclo) alkyl group include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, ( N-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, ( Examples include n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, and the like. These may be used alone or in combination of two or more.

  Examples of the reactive functional group-containing monomer include a monomer having a hydroxyl group in the molecule (hydroxyl group-containing monomer), a monomer having a carboxyl group in the molecule (carboxyl group-containing monomer), and the like. When the adhesive component in the present embodiment is cross-linked by a cross-linking agent, the (meth) acrylic acid ester polymer is excellent in reactivity with the cross-linking agent by using these reactive functional group-containing monomers. It will be a thing. Therefore, in the pressure-sensitive adhesive component after cross-linking with the cross-linking agent, the reactive functional group of the reactive functional group-containing monomer is consumed in the reaction with the cross-linking agent, and the remaining amount is reduced. It is suppressed that durability falls.

  Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, (meth And (meth) acrylic acid hydroxyalkyl esters such as 3-hydroxybutyl acrylate and 4-hydroxybutyl (meth) acrylate. These may be used alone or in combination of two or more.

  Examples of the carboxyl group-containing monomer include ethylenically unsaturated carboxylic acids such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. These may be used alone or in combination of two or more.

  Examples of the reaction catalytic group-containing monomer include a monomer having an amino group in the molecule (amino group-containing monomer) and a monomer having an acrylamide group in the molecule (acrylamide group-containing monomer). The reaction catalytic functional group acts as a catalyst for the reaction between the hydroxyl group of the hydroxyl group-containing monomer and a crosslinking agent capable of reacting with the hydroxyl group.

  Examples of the amino group-containing monomer include a secondary amino group such as (meth) acrylic acid ester having a primary amino group such as aminoethyl (meth) acrylate and n-butylaminoethyl (meth) acrylate ( (Meth) acrylic acid ester, (meth) acrylic acid N, N-dimethylaminoethyl, (meth) acrylic acid N, N-dimethylaminopropyl, and other (meth) acrylic acid esters having a tertiary amino group. These may be used alone or in combination of two or more. In addition, since the (meth) acrylic acid ester having a primary amino group or a secondary amino group has an active hydrogen group, it itself acts as a reactive functional group-containing monomer.

  Examples of the acrylamide group-containing monomer include acrylamide and methacrylamide.

  Examples of the other monomer having no reactive functional group and no reactive catalytic functional group include (meth) acrylic acid ester having an aromatic ring such as phenyl (meth) acrylate, vinyl acetate, and styrene. These may be used alone or in combination of two or more.

  There is no restriction | limiting in particular about the polymerization form of a (meth) acrylic-ester type polymer, A homopolymer may be sufficient and any of a random, a block, or a graft copolymer may be sufficient.

  The molecular weight of the (meth) acrylic acid ester polymer is not particularly limited, but is preferably 10,000 to 5,000,000 in terms of weight average molecular weight, and preferably 100,000 to 3,000,000. Particularly preferred is 30,000 to 2,000,000. When the weight average molecular weight of the (meth) acrylic acid ester-based polymer is within the above range, adhesion to the adherend and adhesion durability are sufficient, and dispersibility of the black pigment can be secured. it can. In addition, the weight average molecular weight in this specification is the value of polystyrene conversion measured by the gel permeation chromatography (GPC) method.

  The said (meth) acrylic-ester type polymer may be used individually by 1 type, and may be used in combination of 2 or more type.

  When the pressure-sensitive adhesive component is cross-linked by a cross-linking agent, the holding power of the obtained pressure-sensitive adhesive is improved, so that the shape as a foil-like pressure-sensitive adhesive is well maintained. The crosslinking agent is not particularly limited as long as it can crosslink the adhesive component, and examples thereof include an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, and a metal chelate crosslinking agent. Of these, polyfunctional isocyanate-based crosslinking agents are preferred.

  The isocyanate-based crosslinking agent contains at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate and xylylene diisocyanate, aliphatic polyisocyanates such as hexamethylene diisocyanate, alicyclic polyisocyanates such as isophorone diisocyanate and hydrogenated diphenylmethane diisocyanate, and the like. , And their biuret bodies, isocyanurate bodies, and adduct bodies that are a reaction product with low molecular active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil.

  Examples of the epoxy crosslinking agent include 1,3-bis (N, N′-diglycidylaminomethyl) cyclohexane, N, N, N ′, N′-tetraglycidyl-m-xylylenediamine, ethylene glycol diglycidyl. Examples include ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane diglycidyl ether, diglycidylaniline, diglycidylamine and the like.

  Examples of the aziridine-based crosslinking agent include diphenylmethane-4,4′-bis (1-aziridinecarboxamide), trimethylolpropane tri-β-aziridinylpropionate, tetramethylolmethanetri-β-aziridinyl. Propionate, toluene-2,4-bis (1-aziridinecarboxamide), triethylenemelamine, bisisophthaloyl-1- (2-methylaziridine), tris-1- (2-methylaziridine) phosphine, And trimethylolpropane tri-β- (2-methylaziridine) propionate.

  Metal chelate crosslinking agents include chelate compounds whose metal atoms are aluminum, zirconium, titanium, zinc, iron, tin, etc., but aluminum chelate compounds are preferred from the viewpoint of performance. Examples of the aluminum chelate compound include diisopropoxy aluminum monooleyl acetoacetate, monoisopropoxy aluminum bis oleyl acetoacetate, monoisopropoxy aluminum monooleate monoethyl acetoacetate, diisopropoxy aluminum monolauryl acetoacetate, diisopropoxy Examples thereof include aluminum monostearyl acetoacetate and diisopropoxy aluminum monoisostearyl acetoacetate.

  The above crosslinking agents may be used individually by 1 type, and may be used in combination of 2 or more type. The amount of use is usually 0.01 to 20 parts by mass, preferably 0.1 to 10 parts by mass, particularly preferably 0.5 to 5 parts by mass with respect to 100 parts by mass of the adhesive component having a crosslinking point. .

(2) Black pigment The black foil-like pressure-sensitive adhesive according to this embodiment contains a black pigment. The type of black pigment is not particularly limited as long as it can impart a black appearance to the pressure-sensitive adhesive, but it is preferable to use carbon black from the viewpoint of cost and low environmental burden.

  Carbon black has different dispersibility in an organic solvent and an adhesive depending on the particle size. The smaller the particle size is, the higher the dispersibility becomes, so it is preferable for improving the concealability (blackness). However, on the other hand, if the particle size of the carbon black is too small, the particles are aggregated and an aggregate having a large diameter is easily formed. If such an aggregate is formed, the dispersibility of carbon black will fall remarkably, and the surface state of the black foil-shaped adhesive obtained will deteriorate. Black pigments other than carbon black often show the same tendency unless particularly surface-treated. From the above, the average particle size of the black pigment is preferably 1 to 20 μm, and particularly preferably 5 to 15 μm.

  Here, the “average particle diameter” in the present specification is a value obtained by measurement with a laser diffraction particle size distribution measuring apparatus.

  Content of the black pigment in the black foil-shaped adhesive (all components) which concerns on this embodiment is 2-6 mass%, Preferably it is 2.2-5 mass%, Most preferably, it is 2.4- 5% by mass. When the content of the black pigment is 2% by mass or more, a black foil-like pressure-sensitive adhesive having a good black appearance and concealability can be obtained. Moreover, since the black foil-like pressure-sensitive adhesive according to this embodiment contains a styrene-maleic acid resin that acts as a dispersant as will be described later, the black foil has a black pigment content of 2% by mass or more. The black pigment in the adhesive is maintained in a uniformly dispersed state. On the other hand, if the content of the black pigment is 6% by mass or less, the black foil-like pressure-sensitive adhesive can contain an adhesive component in an amount capable of exhibiting adhesiveness, and a styrene-maleic acid resin described later can be used. Even if not contained in a large amount, the black pigment is easily dispersed uniformly in the black foil-like pressure-sensitive adhesive.

  In addition, when the black pigment is carbon black, special treatment (for example, solvophilic treatment) may not be performed on the surface. Since the black foil-like pressure-sensitive adhesive according to this embodiment contains a styrene-maleic acid resin as will be described later, even if the black pigment is general (untreated) carbon black, it is uniformly dispersed in the pressure-sensitive adhesive. Can be made.

(3) Styrene-maleic acid resin The black foil-like pressure-sensitive adhesive according to this embodiment contains a styrene-maleic acid resin. Styrene-maleic acid resin is a copolymer of styrene and maleic anhydride, and is also referred to as SMA (Styrene / Maleic Anhydride) resin. The styrene-maleic acid resin is generally positioned as having improved heat resistance of the styrene resin. In the present embodiment, the styrene-maleic acid resin is used as a component for improving the dispersibility of black pigment such as carbon black. That is, the black foil-like pressure-sensitive adhesive according to the present embodiment contains a styrene-maleic acid resin, so that the black pigment is less likely to agglomerate, and even when the black pigment content is large, the black pigment is uniformly distributed. Can be dispersed. Thereby, the black foil-like pressure-sensitive adhesive according to the present embodiment has a good surface state, and has excellent design properties, optical properties, and adhesive strength.

  The content of the styrene-maleic acid resin in the black foil-like pressure-sensitive adhesive according to this embodiment is preferably 2.5 to 10 parts by mass, particularly 2.5 to 5 parts per 1 part by mass of the black pigment. It is preferable that it is a mass part. When the content of the styrene-maleic acid resin is 2.5 parts by mass or more with respect to 1 part by mass of the black pigment, the dispersibility of the black pigment can be stably improved. Moreover, if content of a styrene-maleic acid resin is 2.5-10 mass parts with respect to 1 mass part of black pigment, it will be hard to inhibit the adhesiveness by the adhesion component in a black foil adhesive. Furthermore, if content of a styrene-maleic acid resin is 10 mass parts or less with respect to 100 mass parts of adhesive components, there is no possibility of inhibiting the adhesiveness by the adhesive component in a black foil adhesive, and it is preferable.

(4) Other components The black foil-like pressure-sensitive adhesive according to this embodiment may contain other components in addition to the above three components. Examples of such components include additives such as tackifiers, softeners, antioxidants, ultraviolet absorbers, and light stabilizers.

  Examples of the tackifier include natural resins such as rosin resins and polyterpene resins, petroleum resins such as C5, C9, and dicyclopentadiene, and synthetic resins such as coumarone indene resin and xylene resin. . The tackifier not only increases the adhesiveness of the black foil-like adhesive, but also promotes the dispersibility improving action of the black pigment by the styrene-maleic acid resin. Therefore, the black foil-like adhesive according to this embodiment is an adhesive. It is preferable to contain an imparting agent.

2. Form and physical properties of black foil-like pressure-sensitive adhesive The thickness of the black foil-like pressure-sensitive adhesive according to this embodiment can be appropriately set according to the purpose of use of the black foil-like pressure-sensitive adhesive, but is usually 1 to 100 μm. It is preferably 1 to 30 μm. Since the black foil-like pressure-sensitive adhesive according to this embodiment has a black pigment content of 2% by mass or more, a good black appearance can be achieved even when the thickness is a thin film of about 1 μm.

  The adhesive strength of the black foil adhesive according to this embodiment is preferably 2N / 25 mm or more, and more preferably 4N / 25 mm or more, with respect to the polyethylene plate. In addition, adhesive force here means 180 degree peeling adhesive force 24 hours after pasting according to JISZ0237: 2000. Since the adhesive strength of the black foil-like pressure-sensitive adhesive is within the above range, it can be adhered to a desired adherend (not limited to one made of polyethylene) without causing peeling.

  The degree of black (hiding rate) of the black foil-like pressure-sensitive adhesive can be evaluated by the total light transmittance defined in JIS K7105: 1981. The total light transmittance to be achieved by the black foil-like pressure-sensitive adhesive varies depending on the use of the black foil-like pressure-sensitive adhesive. For example, when used for coloring for the purpose of simply giving design properties, the total light transmittance is preferably 70% or less, and particularly preferably 65% or less. Moreover, when using as a foundation | substrate of the layer which permeate | transmits visible light, or using it as a light leakage prevention use, it is preferable that a total light transmittance is 10% or less, and it is especially preferable that it is 5% or less.

  In order to set the total light transmittance of the black foil-like pressure-sensitive adhesive within a specific range, the thickness (unit: μm) of the black foil-like pressure-sensitive adhesive and the content of black pigment in the black foil-like pressure-sensitive adhesive (unit: mass) %) (Hereinafter referred to as “thickness-content product”) xw (unit: μm · mass%) may be adjusted in accordance with the desired range of total light transmittance. Hereinafter, the thickness-content product xw will be described in detail with reference to the drawings.

  FIG. 1 is a graph showing the relationship between the total light transmittance and the thickness-content product xw when carbon black is used as the black pigment. As shown in FIG. 1, the total light transmittance decreases as the thickness-content product xw increases. Judging from this graph, when it is desired to set the total light transmittance of the black foil-like pressure-sensitive adhesive to 70% or less, it is preferable to adjust the thickness-content product xw to 5 μm · mass% or more. Moreover, when it is desired to set the total light transmittance of the black foil-like pressure-sensitive adhesive to 10% or less, it is preferable to adjust the thickness-content product xw to 35 μm · mass% or more.

  When the thickness-content product xw is 5 μm · mass% or more so that the total light transmittance is 70% or less, the thickness of the black foil-like pressure-sensitive adhesive is preferably 1 to 5 μm, preferably 1 to 4 μm. It is particularly preferable that By setting the thickness of the black foil-like pressure-sensitive adhesive within such a range, the black foil-like pressure-sensitive adhesive can be suitably used even in applications where the black foil-like pressure-sensitive adhesive is required to be extremely thin. The black foil-like pressure-sensitive adhesive according to this embodiment maintains good dispersibility of the black pigment even when the content of the black pigment is high, so even if the thickness of the black foil-like pressure-sensitive adhesive is thus reduced. It is easy to increase the content of the black pigment so that the value of the thickness-content product xw is 5 μm · mass% or more.

  FIG. 2 is a graph showing the relationship between the thickness-content product xw and the adhesive thickness when carbon black is used as a black pigment at different contents. As shown in FIG. 2, the content of carbon black as a black pigment is changed (specifically, 1% by mass, 2% by mass, 2.76% by mass, 3.65% by mass, and 4.65). Mass%), thickness-content product xw and pressure-sensitive adhesive thickness fluctuate, and as the content of black pigment decreases, a certain thickness-content product xw (5 μm / mass% in FIG. 2) The thickness of the pressure-sensitive adhesive required for realizing the above increases. Specifically, when the content of the black pigment is 2% by mass, the thickness-content product xw is 5 μm ·% by mass or more if the thickness of the foil-like pressure-sensitive adhesive is at least 2.5 μm or more. If the content of the black pigment is further increased, the thickness-content product xw can be 5 μm · mass% or more even if the foil-like pressure-sensitive adhesive is thinner. On the other hand, when the content of the black pigment is 1% by mass, the thickness of the foil-like pressure-sensitive adhesive must be 5 μm or more in order to make the thickness-content product xw 5 μm · mass% or more.

  In order to make the total light transmittance 10% or less, when the thickness-content product xw is 35 μm · mass% or more, the thickness of the black foil-like pressure-sensitive adhesive is preferably 10 to 35 μm, preferably 10 to 30 μm. The following is particularly preferable. By setting the thickness of the black foil-like pressure-sensitive adhesive within such a range, the amount of the solvent or dispersion medium to be evaporated at the time of drying after coating can be reduced, thereby improving the productivity and improving the black foil. It is difficult for the adhesive to protrude from the end of the adhesive. The black foil-like pressure-sensitive adhesive according to the present embodiment maintains a good dispersibility of the black pigment even if the content of the black pigment is high. Therefore, even if the thickness is about 30 μm or less, the thickness-content product xw It is easy to maintain the value at 35 μm · mass% or more and to set the total light transmittance to 10% or less.

  FIG. 3 shows a different content of carbon black as a black pigment (specifically, 1% by mass, 2% by mass, 2.76% by mass, 3.65% by mass, and 4.65% by mass as in FIG. 2). %) Is a graph showing the relationship between the thickness-content product xw and the adhesive thickness. When the content of the black pigment is 2% by mass, the thickness-content product xw is 35 μm ·% by mass or more if the thickness of the foil-like pressure-sensitive adhesive is at least 17.5 μm or more. If the content of the black pigment is further increased, the thickness-content product xw can be 35 μm · mass% or more even if the black foil-like pressure-sensitive adhesive is thinner. On the other hand, when the content of the black pigment is 1% by mass, the thickness of the black foil-like pressure-sensitive adhesive needs to be 35 μm or more in order to make the thickness-content product xw 35 μm · mass% or more.

3. Manufacturing method of black foil-shaped adhesive The manufacturing method of the black foil-shaped adhesive which concerns on this embodiment is not specifically limited, It can manufacture by a conventional method. If an example of a manufacturing method is given, first, other components, such as the above-mentioned adhesive component (a crosslinking agent is included depending on necessity), a black pigment, a styrene-maleic acid resin, and a tackifier mix | blended as needed, desired Then, a solvent is mixed to prepare an adhesive composition coating solution. The black pigment and the styrene-maleic acid resin are preferably mixed in advance from the viewpoint of dispersibility of the black pigment.

  Examples of the solvent include aliphatic hydrocarbons such as hexane, heptane, and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, methanol, ethanol, propanol, butanol, 1 -Alcohols such as methoxy-2-propanol, ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, and cyclohexanone, esters such as ethyl acetate and butyl acetate, cellosolv solvents such as ethyl cellosolve, and the like are used.

  The concentration / viscosity of the coating solution of the pressure-sensitive adhesive composition thus prepared is not particularly limited as long as it can be coated, and can be appropriately selected depending on the situation. In addition, when obtaining a pressure-sensitive adhesive solution, the addition of a solvent is not a necessary condition, and it is not necessary to add a solvent as long as the coating liquid of the pressure-sensitive adhesive composition can be coated. The effect of improving the dispersion uniformity of the black pigment by containing the styrene-maleic acid resin of the foil-like adhesive is when the black foil-like adhesive is formed by applying an adhesive composition containing a solvent. , More effective. When the pressure-sensitive adhesive composition does not contain a solvent, the pressure-sensitive adhesive composition is handled as it is as the coating liquid for the pressure-sensitive adhesive composition.

  The coating solution of the adhesive composition prepared as described above is applied to a desired object such as a substrate or a release sheet with a desired thickness and dried to obtain a black foil-like adhesive. As a method for applying the coating solution, for example, a conventionally known method such as a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or a spray coating method can be used. .

  Here, when the (meth) acrylic acid ester-based polymer as the adhesive component is crosslinked, it is preferable to perform a heat treatment. When performing heat processing, it is preferable that heating temperature is 60-150 degreeC, and it is especially preferable that it is 80-120 degreeC. The heating time is preferably 30 seconds to 3 minutes, particularly preferably 50 seconds to 2 minutes. In addition, this heat processing can also serve as the drying process at the time of volatilizing the solvent of the coating liquid of an adhesive composition.

  The black foil-like pressure-sensitive adhesive described above contains a styrene-maleic acid resin, so that the black pigment is uniformly dispersed. Thereby, the surface state is good, the design property (black appearance), Excellent optical properties and adhesive strength. In particular, since the black pigment is uniformly dispersed even if the content is large, the black foil-like pressure-sensitive adhesive can be thinned while having excellent design properties and optical characteristics.

[Black adhesive sheet]
4 and 5 are cross-sectional views of the black pressure-sensitive adhesive sheet according to one embodiment of the present invention. As shown in FIG. 4, the black pressure-sensitive adhesive sheet 1 </ b> A according to the first embodiment includes, in order from the bottom, the release sheet 12, the pressure-sensitive adhesive layer 11 laminated on the release surface of the release sheet 12, and the pressure-sensitive adhesive layer 11. It is comprised from the base material 13 laminated | stacked.

  Further, as shown in FIG. 5, the black adhesive sheet 1B according to the second embodiment is arranged so that the two release sheets 12a and 12b and the release surfaces of the two release sheets 12a and 12b are in contact with each other. It is comprised from the adhesive layer 11 pinched by the sheet | seat of peeling sheet 12a, 12b. In addition, the release surface of the release sheet in this specification refers to a surface having peelability in the release sheet, and includes both a surface that has been subjected to a release treatment and a surface that exhibits peelability without being subjected to a release treatment. .

  In any of the pressure-sensitive adhesive sheets 1A and 1B, the pressure-sensitive adhesive layer 11 is made of the black foil-shaped pressure-sensitive adhesive described above, and the thickness of the pressure-sensitive adhesive layer 11 is as described in the thickness of the black foil-shaped pressure-sensitive adhesive.

  There is no restriction | limiting in particular as the base material 13, All what is used as a base material for normal adhesive sheets can be used, Any of transparent, semi-transparent and opaque may be sufficient, and a color is not limited. For example, polyester films such as polyethylene terephthalate, polybutylene terephthalate and polyethylene naphthalate, polyolefin films such as polyethylene film and polypropylene film, cellulose films such as triacetyl cellulose, polyurethane film, polyurethane acrylate film, polyvinyl chloride film, polyvinylidene chloride Plastic films such as films, polyvinyl alcohol films, ethylene-vinyl acetate copolymer films, polystyrene films, polycarbonate films, acrylic resin films, norbornene resin films, cycloolefin resin films, and liquid crystal polymer films; lamination of two or more of these The body can be mentioned. The plastic film may be uniaxially stretched or biaxially stretched. Moreover, these plastic films do not need to be a single film but may be coated on the surface, or may be a laminate of films such as an adhesive tape. When the base material 13 is a laminate in which the base material, the pressure-sensitive adhesive layer, and the release sheet are laminated in this order from the side in contact with the pressure-sensitive adhesive layer 11, the pressure-sensitive adhesive sheet 1A becomes a double-sided tape.

  As the base material 13, a transparent base material having an uneven surface can also be used. By providing the pressure-sensitive adhesive layer 11 made of a black foil-like pressure-sensitive adhesive on the back surface (surface on which no irregularities are formed) of such a transparent substrate, it is the same as when mat-like black printing is performed on the surface. A pressure-sensitive adhesive sheet with a simple texture can be obtained, and can be produced at a lower cost than by printing.

  Although the thickness of the base material 13 changes with kinds and the intended purpose of 1 A of adhesive sheets, it is 1-500 micrometers normally, Preferably it is 3-300 micrometers, More preferably, it is 5-150 micrometers.

  Examples of the release sheets 12, 12a, 12b include paper substrates such as glassine paper, coated paper, and high-quality paper, laminated paper obtained by laminating a resin such as polyethylene on these paper substrates, or polyethylene terephthalate, polybutylene terephthalate, Examples thereof include a plastic film such as a polyester film such as polyethylene naphthalate, and a polyolefin film such as polypropylene and polyethylene. It is preferable that a release treatment (a surface in contact with the pressure-sensitive adhesive layer 11) is subjected to a release treatment. Examples of the release agent used for the release treatment include silicone-based, fluorine-based, and long-chain alkyl-based release agents.

  One of the release sheets 12a and 12b (for example, the release sheet 12a) is preferably a light release type release sheet, and the other (for example, the release sheet 12b) is preferably a heavy release type release sheet. Thus, in order to provide a peeling force difference between the release sheets 12a and 12b, it can be achieved by changing the type of the release agent, performing a release process on one side, and not performing a release process on the other side.

  Although there is no restriction | limiting in particular about the thickness of release sheet 12, 12a, 12b, Usually, it is about 10-150 micrometers.

  In order to produce the pressure-sensitive adhesive sheet 1A, the pressure-sensitive adhesive composition coating liquid is applied to the release surface of the release sheet 12 and dried to form a pressure-sensitive adhesive layer 11 made of a black foil-like pressure-sensitive adhesive. A base material 13 is laminated on the pressure-sensitive adhesive layer 11.

  Moreover, in order to manufacture the said adhesive sheet 1B, the coating liquid of the adhesive composition mentioned above is apply | coated to the peeling surface of one peeling sheet 12a (or 12b), it is made to dry, and the adhesive which consists of black foil-like adhesives After forming the layer 11, the release surface of the other release sheet 12 b (or 12 a) is overlaid on the pressure-sensitive adhesive layer 11.

  Since the pressure-sensitive adhesive layer 11 of the black pressure-sensitive adhesive sheets 1A and 1B according to the present embodiment is composed of the above-described black foil-like pressure-sensitive adhesive, the black pigment is uniformly dispersed, the surface state is good, the design property, and the optical characteristics. Excellent adhesion. In particular, since the black pigment is uniformly dispersed even if the content is large, the black pressure-sensitive adhesive sheets 1A and 1B can be made thin while having excellent design properties and optical characteristics. Such black pressure-sensitive adhesive sheets 1A and 1B can be suitably used for various applications such as a decorative sheet and a light shielding sheet.

  The embodiment described above is described for facilitating understanding of the present invention, and is not described for limiting the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents belonging to the technical scope of the present invention.

  For example, the release sheet 12 of the adhesive sheet 1A may be omitted, or one of the release sheets 12a and 12b in the adhesive sheet 1B may be omitted.

  EXAMPLES Hereinafter, although an Example etc. demonstrate this invention further more concretely, the scope of the present invention is not limited to these Examples etc.

[Example 1]
100 parts by mass of an adhesive (manufactured by Soken Chemical Co., Ltd., SK Dyne SG-50MT, solid content: 40% by mass) having a (meth) acrylic acid ester polymer as a main component, and a styrene-maleic acid resin dispersion of carbon black ( Toyo Ink Mfg. Co., Ltd., Multirack A-903 Black, solid content 55% by mass (carbon black 14% by mass + styrene-maleic acid resin 41% by mass, carbon black average particle size: 7 μm) 12.3 parts by mass , 1 part by mass of an isocyanate-based crosslinking agent (Toyo Ink Manufacturing Co., Ltd., BHS8515, solid content: 37.5% by mass) and 35 parts by mass of methyl ethyl ketone as a solvent were mixed to prepare a coating solution for an adhesive composition. .

  The film thickness after drying the coating liquid of the above-mentioned pressure-sensitive adhesive composition on the release surface of a release sheet (SP-PET 381031H, thickness 38 μm, manufactured by Lintec Co., Ltd.) obtained by releasing one side of a polyethylene terephthalate film with a silicone release agent is 15 μm. Then, it was applied with a knife coater and dried at 90 ° C. for 1 minute to form an adhesive layer (thickness: 15 μm) composed of a black foil-like adhesive. The carbon black content in the black foil-like pressure-sensitive adhesive was 3.65% by mass. A polyethylene terephthalate (PET) film (thickness: 6 μm) as a substrate was bonded to the surface of the pressure-sensitive adhesive layer, and this was used as a black pressure-sensitive adhesive sheet.

[Example 2]
A black pressure-sensitive adhesive sheet was produced in the same manner as in Example 1 except that the thickness of the black foil-like pressure-sensitive adhesive was adjusted to the numerical value shown in Table 1.

Example 3
80.8 parts by weight of a pressure-sensitive adhesive mainly composed of a (meth) acrylic acid ester polymer (Saiden Chemical Co., Ltd., Cybinol LT-102, solid content: 49.5% by mass), and styrene-maleic acid resin of carbon black 16.4 parts by weight of a dispersion (manufactured by Toyo Ink Manufacturing Co., Ltd., Multilac A-903 Black), 1 part by weight of an isocyanate-based crosslinking agent (manufactured by Toyo Ink Manufacturing Co., Ltd., BHS8515, solid content 37.5% by weight), and a solvent As in Example 1, except that a coating solution of an adhesive composition mixed with 55 parts by mass of methyl ethyl ketone was used and the thickness of the black foil-like adhesive was adjusted to the numerical value shown in Table 1. A black pressure-sensitive adhesive sheet was produced. The carbon black content in the black foil-like pressure-sensitive adhesive was 4.65% by mass.

Example 4
A black pressure-sensitive adhesive sheet was produced in the same manner as in Example 3, except that the thickness of the black foil-like pressure-sensitive adhesive was adjusted to the numerical value shown in Table 1.

Example 5
100 parts by weight of an adhesive (manufactured by Soken Chemical Co., Ltd., SK Dyne 1502C, solid content 40% by weight) having a (meth) acrylic acid ester polymer as a main component, and a styrene-maleic acid resin dispersion of carbon black (Toyo Ink) 8.2 parts by mass manufactured by manufacturer, Multirack A-903 Black), 1 part by mass of isocyanate-based crosslinking agent (manufactured by Toyo Ink Manufacturing Co., Ltd., BHS8515, solid content 37.5% by mass), and 35 masses of methyl ethyl ketone as a solvent A black pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that the coating solution of the pressure-sensitive adhesive composition mixed with the part was used and the thickness of the black foil-like pressure-sensitive adhesive was adjusted to the value shown in Table 1. did. The carbon black content in the black foil-like pressure-sensitive adhesive was 2.56% by mass.

Example 6
A black pressure-sensitive adhesive sheet was produced in the same manner as in Example 5 except that the thickness of the black foil-like pressure-sensitive adhesive was adjusted to the numerical value shown in Table 1.

Example 7
A black pressure-sensitive adhesive sheet was produced in the same manner as in Example 5 except that a filler-kneaded PET film having a concavo-convex surface (Unitika Ltd., PTH-12, thickness: 12 μm) was used instead of the PET film as the substrate. did.

Example 8
A black pressure-sensitive adhesive sheet was prepared in the same manner as in Example 5 except that a white PET film (Teijin DuPont, Teflex, thickness: 13 μm) was used as the substrate instead of the PET film.

[Comparative Example 1]
Example 1 except that instead of carbon black styrene-maleic acid resin dispersion, carbon black cellulose acetate butyrate (CAB) resin dispersion (Toyo Ink, CAB-LX-905 Black) was used. Similarly, a black pressure-sensitive adhesive sheet was produced.

[Comparative Example 2]
A black pressure-sensitive adhesive sheet was prepared in the same manner as in Example 1 except that a carbon black acrylic resin dispersion (manufactured by Sanyo Dye, Colortex Black 702) was used instead of the carbon black styrene-maleic acid resin dispersion.

[Comparative Examples 3 to 6]
Compounding amount of carbon black styrene-maleic acid resin dispersion (manufactured by Toyo Ink Co., Ltd., Multilac A-903 Black) so that the content of carbon black in the black foil-like pressure-sensitive adhesive becomes the value shown in Table 1. A black pressure-sensitive adhesive sheet was prepared in the same manner as in Example 5, except that the thickness of the black foil-like pressure-sensitive adhesive was adjusted to the numerical value shown in Table 1.

[Test Example 1] (Evaluation of surface state of adhesive layer)
The release sheet was peeled from the black adhesive sheet obtained in the examples or comparative examples, and the surface of the exposed adhesive layer (black foil adhesive) was visually observed, and the surface of the adhesive layer was evaluated according to the following evaluation criteria. The state was evaluated. The results are shown in Table 2.
○: Aggregates are not recognized.
X: Aggregates are observed

[Test Example 2] (Measurement of total light transmittance)
In the production of the black pressure-sensitive adhesive sheets of Examples and Comparative Examples, instead of pasting a PET film as a base material, the release-treated surface of a release-treated release sheet (SP-PET 381031H, thickness 38 μm) was bonded. Then, a baseless pressure-sensitive adhesive sheet in which a single pressure-sensitive adhesive layer was sandwiched between two release sheets was obtained. About the obtained base-material-less adhesive sheet, based on JISK7105, the total light transmittance was measured using the integrating-sphere type light transmittance measuring apparatus (Nippon Denshoku Industries Co., Ltd. make, NDH-5000). This measurement was performed three times, and the average value was taken as the measured value. In Comparative Examples 1 and 2 in which aggregates were observed in Test Example 1, no measurement was performed. The results are shown in Table 2.

[Test Example 3] (Measurement of adhesive strength)
The release sheet was peeled from the black pressure-sensitive adhesive sheet obtained in Examples or Comparative Examples, and the exposed pressure-sensitive adhesive layer (black foil-like pressure-sensitive adhesive) was subjected to polyethylene as an adherend in an environment of 23 ° C. and 50% RH. The plate was attached using a 2 kg rubber roller and left in the same environment for 24 hours. Then, using a universal tensile tester (Orientec, Tensilon UTM-4-100), the adhesive layer with the substrate was peeled from the polyethylene film at a peeling angle of 180 ° and a peeling speed of 300 mm / min. The peel force was measured. This measurement was performed three times, and the average value was taken as the measured value. In Comparative Examples 1 and 2 in which aggregates were observed in Test Example 1, no measurement was performed. The results are shown in Table 2.

  As is clear from Table 2, the black pressure-sensitive adhesive sheets obtained in the examples had no aggregation of black pigment, had a good surface state (black appearance), and excellent adhesive strength.

  The black foil-like pressure-sensitive adhesive and the black pressure-sensitive adhesive sheet of the present invention can be suitably used for a decorative sheet, a light shielding sheet, and the like.

DESCRIPTION OF SYMBOLS 1A, 1B ... Adhesive sheet 11 ... Adhesive layer 12, 12a, 12b ... Release sheet 13 ... Base material

Claims (7)

A black foil-like pressure-sensitive adhesive containing an adhesive component, a black pigment, and a styrene-maleic acid resin,
The content of the black pigment in the black foil adhesive is replaced by a Ri 2-6% by mass,
The thickness of the black foil-like pressure-sensitive adhesive is 1 to 5 μm,
The adhesive component is an adhesive mainly composed of a (meth) acrylic acid ester polymer,
The black pigment is carbon black;
The black foil-like pressure-sensitive adhesive , wherein the content of the styrene-maleic acid resin is 2.5 to 10 parts by mass with respect to 1 part by mass of the black pigment .   The black foil-like pressure-sensitive adhesive according to claim 1, wherein the black foil-like pressure-sensitive adhesive has an adhesive strength to a polyethylene plate of 2 N / 25 mm or more. The black foil-like pressure-sensitive adhesive according to claim 1 or 2 , wherein the pressure-sensitive adhesive component is cross-linked by a cross-linking agent. The product xw of the thickness (unit: μm) of the black foil-like pressure-sensitive adhesive and the content (unit: mass%) of the black pigment is 5 μm · mass% or more,
The black foil-like pressure-sensitive adhesive according to any one of claims 1 to 3 , wherein the total light transmittance is 70% or less. The black foil-like pressure-sensitive adhesive according to any one of claims 1 to 4 , wherein the black pigment has an average particle diameter of 1 to 20 µm. A black pressure-sensitive adhesive sheet comprising a base material and a pressure-sensitive adhesive layer,
The said adhesive layer consists of the black foil-like adhesive as described in any one of Claims 1-5 , The black adhesive sheet characterized by the above-mentioned. Two release sheets,
A black pressure-sensitive adhesive sheet comprising a pressure-sensitive adhesive layer sandwiched between the release sheets so as to be in contact with the release surfaces of the two release sheets,
The said adhesive layer consists of the black foil-like adhesive as described in any one of Claims 1-5 , The black adhesive sheet characterized by the above-mentioned.

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