TWI782929B - Adhesive composition and adhesive film - Google Patents

Abstract

The present invention provides an adhesive composition and a surface-protection film, which have an excellent antistatic property and a durability with adhesive property. The adhesive composition contains an acrylic polymer, an antistatic agent and a crosslinking agent. The acrylic polymer has a glass transition temperature of less than 0℃. The antistatic agent is an ionic compound formed by cations and anions and has a melting point of more than 25℃, wherein the anion is at least one selected from the group consisting of trifluoromethanesulfonate anion, pentafluoroethanesulfonate anion, heptafluoropropanesulfonate anion, and nonafluorobutane sulfonate anion. The crosslinking agent is an isocyanate compound with more than three functional groups or an epoxy compound with more than two functional groups. The adhesive composition further contains a monomeric or oligomeric type silane coupling agent having at least one functional group selected from the group consisting of an epoxy group, a mercapto group and an acid anhydride group. The adhesive composition contains 0.01-10 parts by weight of the antistatic agent as an essential component, based on 100 parts by weight of the acrylic polymer.

Description

Adhesive composition and adhesive film

The invention relates to an adhesive composition and an adhesive film containing an antistatic agent. More specifically, it relates to an adhesive combination which contains an ionic compound having a specific sulfonate anion such as nonafluorobutanesulfonate as an antistatic agent and thereby has durability and antistatic performance including excellent adhesive performance Objects, and adhesive films using the adhesive composition.

Various adhesive films for bonding optical members such as polarizing plates and retardation plates to adherends such as liquid crystal cells via an adhesive layer have been proposed (for example, refer to Patent Documents 1 to 2).

Patent Document 1 describes an optical adhesive composition containing an acrylic polymer obtained by copolymerizing an acrylamide compound or the like with monomers such as butyl acrylate as main components.

Patent Document 2 describes an optical adhesive composition containing an acrylic polymer, wherein the acrylic polymer is composed of a (meth)acrylate having an alkyl group having 4 to 8 carbon atoms as a main component. The monomer is formed by copolymerizing carboxyl-containing monomers and nitrogen-containing vinyl monomers.

[Prior art literature] [Patent Document]

Patent Document 1: Japanese Patent Laid-Open No. 2012-177022

Patent Document 2: Japanese Patent Laid-Open No. 2012-201734

However, in the case where the surface of the optical film has been subjected to antifouling treatment or low-reflection surface treatment with a composition containing a polysiloxane compound, etc., when the adhesive film used for such an optical film is peeled from the adherend The peeling electrostatic voltage becomes higher.

In addition, there is a trade-off relationship between the antistatic performance of an adhesive composition having antistatic performance and an adhesive film using the same, and durability including adhesive performance to an adherend. ), it is difficult to improve durability including adhesive performance while maintaining antistatic performance.

Therefore, an adhesive composition is sought, which, even when the surface of the optical film is surface-treated with a composition containing a polysiloxane compound, etc., when the adhesive film is peeled off from the optical film The peeling electrostatic voltage is also suppressed to be low, and it has durability including adhesive performance.

The present invention was made in view of the above circumstances, and provides an adhesive composition capable of achieving both excellent antistatic performance and durability including adhesive performance, and an adhesive film using the adhesive composition.

The inventors of the present application prepared a new adhesive composition containing: the number of carbon atoms of the alkyl group of the (meth)acrylic acid alkyl ester constituting the acrylic polymer constituting the adhesive composition is limited to a specific range , and make a specific combination of two or more kinds of alkyl (meth)acrylates copolymerized, and an ionic compound having a specific sulfonate anion such as nonafluorobutanesulfonate with a melting point of 25°C or higher Formed antistatic agent. Thus, it has been found that an adhesive composition that has durability including excellent adhesive performance and excellent anti-peeling static electricity performance that does not deteriorate with time, compared with the conventional adhesive composition for an adhesive film, has been found, The present invention has thus been accomplished.

In particular, it has been found that compared with the prior art, the adhesive film according to the present invention has durability including excellent adhesive performance, and has excellent anti-peeling static performance that does not deteriorate with time, so it can realize antistatic performance at the same time. And the effect of durability including adhesive performance.

In order to solve the above technical problems, the present invention provides an adhesive composition, which contains an acrylic polymer, an antistatic agent and a crosslinking agent, wherein the acrylic polymer has a glass transition temperature below 0°C, so The (D) crosslinking agent is one or more crosslinking agents selected from the group consisting of trifunctional or higher isocyanate compounds and difunctional or higher epoxy compounds, and the adhesive composition further contains (H) containing selected Monomer or oligomer silane coupling agent with at least one or more functional groups from the group consisting of epoxy, mercapto, and acid anhydride groups. The antistatic agent is composed of cations and anions and has a melting point above 25°C. An ionic compound, the anion is one selected from the group consisting of trifluoromethanesulfonate anion, pentafluoroethanesulfonate anion, heptafluoropropanesulfonate anion, and nonafluorobutanesulfonate anion, relative to 100 parts by weight The said acrylic polymer contains the said antistatic agent as an essential component in the ratio of 0.01-10 weight part.

Preferably: the acrylic polymer is at least one of (A) alkyl (meth)acrylic acid alkyl ester monomers whose carbon atoms are C1 to C14, (B) copolymerization containing hydroxyl and/or carboxyl groups An acrylic polymer of a copolymer formed by copolymerization of at least one of vinyl monomers and (C) at least one of copolymerizable vinyl monomers containing aromatic groups, in the acrylic polymer, relatively In the total of 100 parts by weight of the above-mentioned (A) and the above-mentioned (C), the proportion of the total of 0.1 to 5 parts by weight of the (B) copolymerizable vinyl monomer containing a hydroxyl group and/or carboxyl group is contained. At least one, in a test piece obtained by attaching a 20 μm thick adhesive layer obtained by crosslinking the adhesive composition to a polarizing plate with a total thickness of 80 μm, the 20 μm thick adhesive layer The adhesion to alkali-free glass is below 6N/25mm, and there is no blistering or falling off after the durability test at 105°C×500hr.

The cation is preferably selected from the group consisting of pyridinium, imidazolium, phosphonium, permeum, pyrrolidinium, guanidinium, ammonium, isouronium (isouronium), thiouronium (thiouronium), piperidinium, pyrazolium (pyrazolium) , methylium (methylium), lithium, morpholinium (morpholinium) in the group consisting of one.

The surface resistivity of the adhesive layer obtained by crosslinking the adhesive composition is preferably 1.0×10 ⁺¹² Ω/□ or less.

Preferably: the (B) copolymerizable vinyl monomers containing hydroxyl and/or carboxyl groups are at least one or more selected from the group consisting of copolymerizable monomers containing hydroxyl groups and copolymerizable monomers containing carboxyl groups. The copolymerizable monomer of the hydroxyl group is selected from (meth)acrylate-8-hydroxyoctyl ester, (meth)acrylate-6-hydroxyhexyl ester, (meth)acrylate-4-hydroxybutyl ester, (meth)acrylic acid -At least one of the compound group consisting of 2-hydroxyethyl ester, N-hydroxyl (meth)acrylamide, N-hydroxymethyl (meth)acrylamide, N-hydroxyethyl (meth)acrylamide More than one, the carboxyl-containing copolymerizable monomer is selected from (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2-(meth)acryloxy 2-(meth)acryloxypropylhexahydrophthalate, 2-(meth)acryloxyethylhexahydrophthalate, 2-(meth)acryloxyethylhexahydrophthalate, base) acryloxyethylsuccinic acid, 2-(meth)acryloxyethylmaleic acid, carboxypolycaprolactone mono(meth)acrylate, 2-(meth)acryloxy At least one or more of the compound group consisting of ethyl tetrahydrophthalic acid.

Furthermore, the present invention provides an adhesive film characterized in that an adhesive layer obtained by crosslinking the above-mentioned adhesive composition is laminated on one side of the resin film.

Furthermore, the present invention provides an optical film with an adhesive layer, in which an adhesive layer obtained by crosslinking the above-mentioned adhesive composition is laminated on at least one surface of the optical film.

Furthermore, the present invention provides an adhesive film in which antistatic treatment and antifouling treatment are applied to one side of the resin film, that is, the side opposite to the side on which the adhesive layer is laminated.

Moreover, this invention provides the adhesive film for polarizing plates using the above-mentioned adhesive film.

Furthermore, the present invention provides an adhesive film characterized in that an adhesive layer formed by crosslinking the above adhesive composition is laminated on one side of a release film so as to have a thickness of 1 μm to 25 μm, The structure of release film/adhesive layer/release film.

In addition, the present invention provides a liquid crystal panel, which is characterized in that the liquid crystal panel uses the above-mentioned optical film with an adhesive layer.

According to the present invention, it is possible to provide an adhesive composition and an adhesive film capable of achieving both excellent antistatic performance and durability including adhesive performance.

The adhesive composition and the adhesive film using the adhesive composition according to the present invention, even when the surface of the optical film as an adherend is surface-treated with a composition containing a silicone compound or the like, Compared with the prior art, it also has durability including excellent adhesive performance, and has excellent anti-peeling static electricity performance that does not deteriorate with time.

That is, the adhesive composition and the adhesive film using the adhesive composition according to the present invention have excellent antistatic performance and durability including excellent adhesive performance, and thus have great industrial utility value.

Hereinafter, the present invention will be described based on preferred embodiments.

The adhesive composition of this embodiment contains an acrylic polymer, an antistatic agent, and a crosslinking agent, wherein the acrylic polymer has a glass transition temperature below 0°C, and the (D) crosslinking agent is One or more crosslinking agents selected from the group consisting of trifunctional or higher isocyanate compounds and difunctional or higher epoxy compounds, and the adhesive composition further contains (H) a crosslinking agent selected from the group consisting of epoxy groups, mercapto groups, and acid anhydrides. Monomer or oligomer type silane coupling agent with at least one or more functional groups in the group consisting of groups, the antistatic agent is an ionic compound formed by cations and anions with a melting point above 25°C, and the anions are One selected from the group consisting of trifluoromethanesulfonate anion, pentafluoroethanesulfonate anion, heptafluoropropanesulfonate anion, and nonafluorobutanesulfonate anion, with respect to 100 parts by weight of the acrylic polymer, with The antistatic agent is contained as an essential component in a ratio of 0.01 to 10 parts by weight.

In addition, it is preferable that the antistatic agent is an ionic compound that is solid at a temperature of 25° C. and has a melting point of 25° C. or higher, and it is more preferable that the melting point of the antistatic agent is 450° C. or lower.

The acrylic polymer used in the adhesive composition of the present embodiment has a glass transition temperature of 0° C. or lower. In addition, the acrylic polymer is preferably a copolymer mainly composed of at least one of (A) alkyl (meth)acrylate monomers whose alkyl group has C1 to C14 carbon atoms.

In addition, examples of (A) alkyl (meth)acrylate monomers in which the alkyl group has C1 to C14 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, (meth)acrylate, ) propyl acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, heptyl (meth) acrylate, (meth) Octyl acrylate, Isooctyl (meth)acrylate, 2-Ethylhexyl (meth)acrylate, Nonyl (meth)acrylate, Isononyl (meth)acrylate, Decyl (meth)acrylate , Undecyl (meth)acrylate, Lauryl (meth)acrylate, Tridecyl (meth)acrylate, Myristyl (meth)acrylate, (Meth)acrylic acid Cyclopentyl ester, cyclohexyl (meth)acrylate, etc. The alkyl group of the alkyl (meth)acrylate monomer may be linear, branched, or cyclic.

The acrylic polymer used in the adhesive composition of this embodiment can copolymerize (B) at least 1 sort(s) of the copolymerizable vinyl monomer containing a hydroxyl group and/or carboxyl group as an optional component. (B) Copolymerizable vinyl monomers containing hydroxyl and/or carboxyl groups include those selected from copolymerizable monomers containing hydroxyl groups (hydroxyl-containing monomers) and copolymerizable monomers containing carboxyl groups (carboxyl-containing monomers). ) at least one of the group consisting of. That is, only either one of a hydroxyl group-containing monomer or a carboxyl group-containing monomer may be selected and copolymerized, or both of a hydroxyl group-containing monomer and a carboxyl group-containing monomer may be copolymerized.

In the acrylic polymer, it is preferably in a ratio of 0.1 to 5 parts by weight in total, more preferably in a ratio of 0.1 to 4.2 parts by weight in total, based on 100 parts by weight of said (A) and said (C) in total. , It is particularly preferable to contain (B) at least one of copolymerizable vinyl monomers containing hydroxyl and/or carboxyl groups in a ratio of 0.1 to 2.8 parts by weight in total.

In addition, examples of hydroxyl-containing monomers include those selected from the group consisting of 8-hydroxyoctyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, ( 2-hydroxyethyl methacrylate, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, etc. At least one or more of the compound group. Among the acrylic polymers, the proportion of the hydroxyl group-containing monomer contained in the adhesive composition of the present embodiment is preferably 0.1 to 5 parts by weight relative to 100 parts by weight of the above-mentioned (A) and the above-mentioned (C) in total. The ratio of parts is more preferably a ratio of 0.1 to 4.2 parts by weight, particularly preferably a ratio of 0.1 to 2.8 parts by weight.

In addition, examples of carboxyl group-containing monomers include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, 2-(meth)acryloxyethyl 2-(meth)acryloxypropylhexahydrophthalic acid, 2-(meth)acryloxyethylhexahydrophthalic acid, 2-(methyl) Acryloxyethylsuccinic acid, 2-(meth)acryloxyethylmaleic acid, carboxypolycaprolactone mono(meth)acrylate, 2-(meth)acryloxyethyl At least one or more of the compound group consisting of tetrahydrophthalic acid and the like. In the acrylic polymer, the ratio of the carboxyl group-containing monomer in the adhesive composition according to the present embodiment is preferably 0 to 5.0 parts by weight with respect to a total of 100 parts by weight of the above-mentioned (A) and the above-mentioned (C). (The situation of non-copolymerized carboxyl-containing monomers is also allowed), in the case of copolymerizing carboxyl-containing monomers, it is more preferably a ratio of 0.1 to 5 parts by weight, particularly preferably a ratio of 0.1 to 2.4 parts by weight, most preferably 0.1~1.2 parts by weight.

The acrylic polymer used in the adhesive composition of this embodiment can copolymerize (C) the copolymerizable vinyl monomer containing an aromatic group as an optional component. Examples of (C) aromatic group-containing copolymerizable vinyl monomers include benzyl (meth)acrylate, naphthyl (meth)acrylate, phenoxyethyl (meth)acrylate, ( Phenoxybutyl methacrylate, 2-(1-naphthyloxy)ethyl (meth)acrylate, 2-(2-naphthyloxy)ethyl (meth)acrylate, (methyl) 6-(1-naphthyloxy)hexyl acrylate, 6-(2-naphthyloxy)hexyl (meth)acrylate, 8-(1-naphthyloxy)octyl (meth)acrylate, At least one or more of 8-(2-naphthyloxy)octyl (meth)acrylate and the like. In the case of containing an aromatic group-containing (meth)acrylate monomer as an aromatic group-containing copolymerizable vinyl monomer, since it is excellent in copolymerizability with an alkyl (meth)acrylate monomer, Therefore preferred.

The method for producing the acrylic polymer contained in the adhesive composition according to the present embodiment is not particularly limited, and an appropriate known polymerization method such as a solution polymerization method or an emulsion polymerization method can be used. The weight-average molecular weight of the copolymer of the acrylic polymer used in the adhesive composition according to the present embodiment is preferably 1 million to 3 million.

In order to acquire antistatic performance, the adhesive composition which concerns on this embodiment contains (G) antistatic agent. (G) The antistatic agent is an ionic compound formed by a cation and an anion with a melting point above 25°C, and the anion is selected from trifluoromethanesulfonate anion (CF ₃ SO ₃ ^- ), pentafluoroethanesulfonate anion (CF ₃ CF ₂ SO ₃ ^- ), heptafluoropropanesulfonate anion (CF ₃ CF ₂ CF ₂ SO ₃ ^- ), nonafluorobutanesulfonate anion (CF ₃ CF ₂ CF ₂ CF ₂ SO ₃ ^- ) A sort of. The adhesive composition according to this embodiment preferably contains (G) an antistatic agent as an essential component in a ratio of 0.01 to 10 parts by weight relative to 100 parts by weight of the acrylic polymer. In order to reduce the lower limit value of the surface resistivity to 1.0×10 ⁺¹⁰ Ω/□ or less, it is more preferable to contain (G) an antistatic agent in a ratio of 0.01 to 15 parts by weight.

In addition, examples of cations contained in ionic compounds include those selected from pyridinium, imidazolium, phosphonium, permedium, pyrrolidinium, guanidinium, ammonium, isouronium, thiouronium, piperidinium, pyrazolium, One of the group consisting of methylium, lithium, and morpholinium.

In addition, specific examples of (G) antistatic agents include lithium trifluoromethanesulfonate, lithium nonafluorobutanesulfonate, 1-methyl-3-octylpyridinium trifluoromethanesulfonate, 3 -Methyl-1-octylpyridinium trifluoromethanesulfonate, 1-methyl-4-octylpyridinium nonafluorobutanesulfonate, 4-methyl-1-octylpyridinium nonafluorobutane Alkanesulfonate, dimethyldioctylammonium pentafluoroethanesulfonate, 1-methyl-3-octylpyridinium heptafluoropropanesulfonate, 3-methyl-1-octylpyridinium heptafluoropropanesulfonate salt, 1-methyl-3-octylpyridinium nonafluorobutanesulfonate, 3-methyl-1-octylpyridinium nonafluorobutanesulfonate, 1-octyl-3-methylimidazole Onium nonafluorobutane sulfonate, etc.

The adhesive composition according to this embodiment further contains at least one or more crosslinking agents selected from the group consisting of trifunctional or higher functional isocyanate compounds and difunctional or higher functional epoxy compounds as (D) crosslinking agent. As the (D) crosslinking agent, a trifunctional or higher isocyanate compound and a difunctional or higher epoxy compound can be used together. (D) The total content ratio of at least one or more crosslinking agents is, for example, preferably 0.01 to 5 parts by weight, more preferably 0.01 to 2 parts by weight, and particularly preferably 0.03~0.8 parts by weight.

In addition, examples of isocyanate compounds having more than three functions include hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, toluene diisocyanate, and xylylene diisocyanate. Isocyanate-based biuret-modified products or isocyanurate-modified products, adducts with trimethylolpropane, glycerin, and other trivalent or higher polyhydric alcohols, and the like.

In addition, examples of the epoxy compound having more than bifunctionality include diol-based diglycidyl ether, bisphenol-based diglycidyl ether, trihydric alcohol-based triglycidyl ether, and dicarboxylic acid diglycidyl ether. Esters, diglycidyl substituted amines, tetraglycidyl substituted diamines, etc.

The adhesive composition according to this embodiment further contains (H) a silane coupling agent. Examples of the (H) silane coupling agent include compounds having at least one organic functional group and at least one hydrolyzable group in one molecule, wherein the hydrolyzable group is an alkoxy group bonded to a silicon atom, or the like. (H) The silane coupling agent contains at least one or more functional groups selected from the group consisting of epoxy groups, mercapto groups, and acid anhydride groups. (H) As the silane coupling agent, one or both of monomer type and oligomer type can be used. The content ratio of the silane coupling agent is, for example, preferably 0.01 to 2.0 parts by weight, more preferably 0.01 to 1.0 parts by weight, and particularly preferably 0.01 to 0.5 parts by weight, based on 100 parts by weight of the acrylic polymer.

In addition, examples of the silane coupling agent having an epoxy group include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyl Oxypropylmethyldimethoxysilane, 3-glycidoxypropyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 2-(3,4 -Epoxycyclohexyl)ethylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethylmethyldiethoxysilane, 2-(3,4-epoxycyclohexyl) Ethyltriethoxysilane, 5,6-epoxyhexyltrimethoxysilane, 5,6-epoxyhexylmethyldimethoxysilane, 5,6-epoxyhexylmethyldiethoxysilane, 5,6-epoxyhexyltriethoxysilane, etc.

In addition, examples of the silane coupling agent having a mercapto group include 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldiethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, etc.

In addition, examples of the silane coupling agent having an acid anhydride group include 3-trimethoxysilylpropyl succinic anhydride, 3-triethoxysilylpropyl succinic anhydride, 3-dimethylmethoxysilyl Propyl succinic anhydride, 3-dimethylethoxysilylpropyl succinic anhydride, 3-trimethoxysilylpropylcyclohexyl dicarboxylic anhydride, 3-triethoxysilylpropylcyclohexyl dicarboxylic anhydride , 3-Dimethylmethoxysilylpropyl cyclohexyl dicarboxylic anhydride, 3-Dimethylethoxysilylpropyl cyclohexyl dicarboxylic anhydride, 3-trimethoxysilylpropyl cyclohexyl dicarboxylic anhydride Anhydride, 3-triethoxysilylpropyl phthalic anhydride, etc.

In addition, an alkoxy oligomer obtained by oligomerization (an alkoxy group-containing siloxane alkoxy oligomer) or the like can also be used as a silane coupling agent.

In addition, silicone alkoxy oligomers, such as tetraalkoxysiloxanes, trialkoxysiloxanes, and trialkoxysiloxanes whose molecular ends are capped with alkoxysilyl groups represented by Si-OR, are preferably used. Silicone alkoxy oligomers with a molecular weight of 600 to less than 3000 and a relatively small molecular weight such as dialkoxysiloxane.

Not limited to the above-mentioned additives, the adhesive composition of this embodiment may also be appropriately blended with known antioxidants, surfactants, curing accelerators, plasticizers, fillers, curing retarders, processing aids, anti-aging agents, etc. additives. These additives may be used alone or in combination of two or more.

For the adhesive layer obtained by crosslinking the adhesive composition of this embodiment, the surface resistivity of the adhesive layer is preferably 1.0×10 ⁺¹² Ω/□ or less, more preferably 5.0×10 ^{+ 11} Ω/□ or less, particularly preferably 2.0×10 ⁺¹¹ Ω/□ or less in surface resistivity. When the surface resistivity is high, the performance of releasing static electricity due to charging is poor when the adhesive layer is peeled off from the adherend. Therefore, by sufficiently reducing the surface resistivity of the adhesive layer, it is possible to reduce the peeling electrostatic voltage generated by the static electricity generated when the adhesive layer is peeled from the adherend, and suppress the influence on the adherend.

In the adhesive composition of this embodiment, in the test piece obtained by bonding the adhesive layer with a thickness of 20 μm obtained by crosslinking the adhesive composition to a polarizing plate with a total thickness of 80 μm, the thickness is The adhesion of the 20 μm adhesive layer to the alkali-free glass is below 6N/25mm, and there is no blistering or falling off after the durability test at 105°C×500hr. The adhesive force of the adhesive layer with a thickness of 20 μm to the alkali-free glass is preferably not less than 1N/25mm and not more than 6N/25mm, more preferably not less than 1.5N/25mm and not more than 6N/25mm.

The adhesive layer according to the present embodiment can be obtained by applying the adhesive composition of the present embodiment on a substrate such as a resin film or a release film, and then crosslinking the adhesive composition.

When using the adhesive layer which concerns on this embodiment for bonding of an optical member, it is necessary to reduce the reflection of the light of the interface of an adhesive layer and an optical member. That is, it is desired that the difference in refractive index between the optical member and the adhesive layer be as small as possible. Therefore, the refractive index of the adhesive layer is preferably 1.47 to 1.50.

The adhesive film according to this embodiment can be produced by forming the adhesive layer according to this embodiment on one surface of a substrate such as a resin film or a release film. A polyester film etc. can be used as a base material of a resin film or a release film (separator film). For the release film, release treatment can be performed on the surface on the side that is bonded to the adhesive surface of the adhesive layer using a silicone-based or fluorine-based release agent. In the resin film used as the base material of the adhesive film according to this embodiment, a silicone-based or fluorine-based mold release agent or coating agent may be applied to the surface of the resin film opposite to the side on which the adhesive layer is formed. , antifouling treatment of silica particles, etc., antistatic treatment based on antistatic agent coating or kneading, etc. In addition, the thickness of the adhesive layer of the adhesive film according to the present embodiment is, for example, preferably 1 μm to 25 μm, more preferably 3 μm to 20 μm, and particularly preferably 5 μm to 20 μm.

The adhesive film according to this embodiment can also be formed as "release film/adhesive layer/release film" by affixing the release film's release-treated surface to both sides of one adhesive layer. structure. In this case, by peeling off the release film of both sides sequentially or simultaneously, and exposing an adhesive surface, it can bond with optical members, such as an optical film. Examples of the optical film include polarizing films, retardation films, antireflection films, antiglare (anti glare) films, ultraviolet absorbing films, infrared absorbing films, optical compensation films, and brightness improving films. Examples of devices to which the optical member is applied include a liquid crystal panel, an organic EL panel, a touch panel, and the like.

The adhesive film according to this embodiment is suitable as an adhesive film for polarizing plates. An optical film with an adhesive layer obtained by laminating the above-mentioned adhesive layer on at least one surface of the above-mentioned optical film can be formed. In addition, a polarizing plate with an adhesive layer can be provided by using the above-mentioned adhesive film on one side of the polarizing plate. A liquid crystal panel can be provided by using the above-mentioned optical film with an adhesive layer.

Specific examples of the laminated structure of such an optical film with an adhesive layer include "release film/adhesive layer/optical film", "release film/adhesive layer/optical film/adhesive layer/release film" type film", "optical film/adhesive layer/optical film", "optical film/adhesive layer", "adhesive layer/optical film/adhesive layer", etc. Specific examples of the laminated structure of a polarizer with an adhesive layer include "release film/adhesive layer/polarizer", "release film/adhesive layer/polarizer/adhesive layer/release film" ", "Polarizer/Adhesive Layer", "Adhesive Layer/Polarizer/Adhesive Layer", etc. As a partial structure of a liquid crystal panel, etc., you may have these optical films with an adhesive layer, or the polarizing plate with an adhesive layer.

In addition, when the release film is included in the laminated structure like "release film/adhesive layer/optical film" and "release film/adhesive layer/polarizer", peel the release film After being attached, the optical film or polarizer is attached to the adherend through the adhesive layer.

[Example]

Hereinafter, the present invention will be specifically described using examples.

<Preparation of Acrylic Polymer>

[Example 1]

Nitrogen gas was introduced into a reaction device equipped with a stirrer, a thermometer, a reflux cooler, and a nitrogen gas introduction pipe, thereby replacing the air in the reaction device with nitrogen gas. Then, add 50 parts by weight of butyl acrylate, 10 parts by weight of methyl acrylate, 20 parts by weight of 2-ethylhexyl acrylate, 1.0 parts by weight of 6-hydroxyhexyl acrylate, 0.5 Along with 4-hydroxybutyl acrylate and 20 parts by weight of benzyl acrylate, 100 parts by weight of a solvent (ethyl acetate) was added. Then, 0.1 weight part of azobisisobutyronitrile was dripped as a polymerization initiator over 2 hours, and it was made to react at 65 degreeC for 8 hours, and the acrylic polymer solution of Example 1 was obtained.

[Examples 2 to 6 and Comparative Examples 1 to 3]

In the same manner as the acrylic polymer solution used in the above-mentioned Example 1, except that the composition of the monomers was set as described in Table 1, the obtained compounds used in Examples 2 to 6 and Comparative Examples 1 to 3 were obtained. acrylic polymer solution.

<Preparation of Adhesive Composition and Adhesive Film>

[Example 1]

To the acrylic polymer solution of Example 1 prepared as described above, D-110N was added in a proportion of 0.1 parts by weight and T-X was added in a proportion of 0.01 parts by weight as a crosslinking agent, and 1 -Methyl-3-octylpyridinium nonafluorobutanesulfonate is used as an antistatic agent, and KBM-403 is added in a ratio of 0.1 parts by weight and X-41-1805 is added in a ratio of 0.1 parts by weight as a silane coupling agent, Stirring and mixing were performed to obtain the adhesive composition of Example 1. The adhesive composition was coated on a release film formed of a polyethylene terephthalate (PET) film coated with a silicone resin, and dried at 90° C. to remove the solvent to obtain Adhesive layer with a thickness of 20 μm. Then, by aging at 23° C. and 50% RH atmosphere for 7 days, a release film/adhesive film having an adhesive layer formed by crosslinking the adhesive composition on one side of the release film was obtained. The adhesive film of Example 1 of the structure of the agent layer/release film.

[Examples 2 to 6 and Comparative Examples 1 to 3]

The adhesive films of Examples 2 to 6 and Comparative Examples 1 to 3 were obtained in the same manner as the adhesive film of Example 1 above, except that the compositions of the additives were as described in Table 1.

In Table 1, the parts by weight of each component are obtained by combining (A) at least one of (meth)acrylic acid alkyl ester monomers with C1~C14 carbon atoms in the alkyl group and (C) aromatic group-containing The total amount of at least one of the copolymerizable vinyl monomers in 100 parts by weight was calculated.

In addition, in Table 1, in each column of (D), (H), and (G), the acrylic polymer is defined as 100 parts by weight, and the content ratio (parts by weight) of each component is represented by the numerical value in parentheses ( ). ).

In addition, the compound names of the abbreviated symbols of each component used in Table 1 are shown in Table 2. G-1 to G-7 are all ionic compounds with a melting point of 25°C or higher and solid at 25°C.

In addition, CORONATE (registered trademark) HX, CORONATE HL and CORONATE L are trade names of TOSOH CORPORATION, D-110N, D-127N, TAKENATE (registered trademark) D-140N are trade names of Mitsui Chemicals, Inc., TETRAD (registered Trademark)-X is a trade name of MITSUBISHI GAS CHEMICAL COMPANY, INC. In addition, HDI means hexamethylene diisocyanate, IPDI means isophorone diisocyanate, XDI means xylylene diisocyanate, TDI means toluene diisocyanate, and TMP means trimethylolpropane. In addition, KBM-403, X-12-967C, and X-41-1805 are all trade names of Shin-Etsu Chemical Co., Ltd.

<Test method and evaluation>

The adhesive films in Examples 1 to 6 and Comparative Examples 1 to 3 were aged in an atmosphere of 23° C. and 50% RH for 7 days, respectively, and then evaluated by the following test methods.

<Adhesion Test Method>

The release film on one side was peeled off from the adhesive films in Examples 1 to 6 and Comparative Examples 1 to 3 to expose one side of the adhesive layer of the adhesive film. Then, the adhesive film was bonded to one side of a polarizer (using a resin film; the protective layer of the polarizer is a TAC polarizer) with a thickness of 80 μm through the adhesive layer to obtain a release film. /adhesive layer/polarizer structure of the polarizer with an adhesive layer. Further, the release film of the polarizing plate with an adhesive layer was peeled off, and the polarizing plate with an adhesive layer was bonded to an alkali-free glass (EAGLE XG manufactured by Corning Incorporated) through the adhesive layer with a pressure roller. The surface that had been cleaned with acetone was prepared as a test piece. Then, the test piece was autoclaved at 50° C. and 0.5 MPa×20 minutes. Then, return to the atmosphere of 23°C x 50%RH, and measure the peel strength of the polarizing plate with the adhesive layer after 1 hour in accordance with JIS Z0237 "Test method for adhesive tape and adhesive sheet" using a tensile tester. The peeling strength when peeling at a speed of 0.3 m/min in the 180° direction was used as the adhesion force of the adhesive layer to the alkali-free glass.

<Test method for surface resistivity>

After curing the adhesive film, before attaching it to the adherend, the release film was peeled off to expose the adhesive layer, and the adhesive was measured using a resistivity meter HIRESTA UP-HT450 (manufactured by Mitsubishi Chemical Analytech Co., Ltd.). The surface resistivity of the layer was measured.

<Durability test method>

Using the same method as the measurement of the adhesive force, peel off the release film of the polarizing plate with an adhesive layer of 10 cm square, and attach it to the surface of the non-alkali glass that has been cleaned with acetone, thereby preparing a test piece. . Then, the test piece was subjected to a durability test under a test environment of 105°C×500hr, and then taken out into an atmosphere of 23°C×50%RH, and the state of the adhesive layer was visually observed after 1 hour, and the durability of the adhesive layer was judged. sex. The criteria for judging the durability are: "○" when there is no blistering or peeling off of the adhesive layer; "△" when a part of the adhesive layer is blistered or peeling off; The case where foaming and peeling occurred was evaluated as "x".

Table 3 shows the evaluation results of the adhesive films in Examples 1 to 6 and Comparative Examples 1 to 3. "Surface resistivity" is expressed by expressing "m×10 ⁺ⁿ " as "mE+n" (where m is an arbitrary real value and n is a positive integer).

Regarding the adhesive films of Examples 1 to 6, the surface resistivity of the adhesive layer is 1.0×10 ⁺¹² Ω/□ or less, the adhesive force of the 20 μm adhesive layer to the alkali-free glass is 6 N/25 mm or less, and the adhesive layer is No blistering and falling off after the durability test of ×500hr, not only excellent adhesive performance and antistatic performance, but also excellent durability.

That is, the evaluation results of the adhesive films of Examples 1 to 6 shown in Table 3 confirmed that the problems of the present invention could be solved.

Since the adhesive film of Comparative Example 1 used an ionic compound having PF ₆ ^-anions as the (G) antistatic agent contained in the adhesive composition, the adhesive layer had a high surface resistivity and poor durability.

Regarding the adhesive film of Comparative Example 2, the glass transition temperature of the acrylic polymer contained in the adhesive composition exceeded 0° C. (calculated value +4.8° C.). Therefore, the adhesive performance is poor, the adhesive force is too large, the surface resistivity of the adhesive layer is high, and the durability is poor. In addition, in the acrylic polymer used in Comparative Example 2, the ratio of methyl acrylate and acrylic acid in which the glass transition temperature of the homopolymer is a high value (exceeding 0° C.) was large.

Regarding the adhesive film of Comparative Example 3, since neither the (H) silane coupling agent nor the (G) antistatic agent was blended in the adhesive composition, the adhesive force was too large, and the surface resistivity of the adhesive layer was high. Poor durability.

As mentioned above, the adhesive films of Comparative Examples 1 to 3 could not solve the technical problem of the present invention.

Claims (10)

A kind of adhesive composition, described adhesive composition contains acrylic polymer, antistatic agent and (D) crosslinking agent, it is characterized in that, described acrylic polymer is only made of the carbon of (A) alkyl At least one of (meth)acrylic acid alkyl ester monomers with atomic numbers of C1~C14, (B) at least one of copolymerizable vinyl monomers containing hydroxyl and/or carboxyl groups, and (C) containing aromatic groups A copolymer having a glass transition temperature below 0°C and having a glass transition temperature below 0°C obtained by copolymerizing at least one of the copolymerizable vinyl monomers of the group, and the (D) crosslinking agent is selected from trifunctional or higher isocyanate compounds and bifunctional or higher One or more crosslinking agents in the group consisting of epoxy compounds, and the adhesive composition further contains (H) a crosslinking agent containing at least one or more functional groups selected from the group consisting of epoxy groups, mercapto groups, and acid anhydride groups. Monomer or oligomeric silane coupling agent, the antistatic agent is selected from lithium trifluoromethanesulfonate, lithium nonafluorobutanesulfonate, 1-methyl-3-octylpyridinium trifluoromethane Sulfonate, 3-methyl-1-octylpyridinium trifluoromethanesulfonate, 1-methyl-4-octylpyridinium nonafluorobutanesulfonate, 4-methyl-1-octyl Pyridinium nonafluorobutanesulfonate, dimethyldioctylammonium pentafluoroethanesulfonate, 1-methyl-3-octylpyridinium heptafluoropropanesulfonate, 3-methyl-1-octyl Pyridinium heptafluoropropanesulfonate, 1-methyl-3-octylpyridinium nonafluorobutanesulfonate, 3-methyl-1-octylpyridinium nonafluorobutanesulfonate, and 1-octyl - More than one of the group consisting of 3-methylimidazolium nonafluorobutanesulfonate, The antistatic agent is contained as an essential component in a ratio of 0.01 to 10 parts by weight relative to 100 parts by weight of the acrylic polymer. The adhesive composition as described in item 1 of the scope of the patent application, wherein, in the acrylic polymer, relative to the total of 100 parts by weight of the (A) and the (C), the total amount is 0.1~ Containing at least one of the (B) copolymerizable vinyl monomers containing hydroxyl and/or carboxyl groups in a ratio of 5 parts by weight, the adhesive layer with a thickness of 20 μm formed by crosslinking the adhesive composition In the test piece attached to a polarizing plate with a total thickness of 80 μm, the adhesive force of the adhesive layer with a thickness of 20 μm to alkali-free glass was 6 N/25mm or less, and after a durability test at 105°C×500hr No blistering and shedding. The adhesive composition according to claim 1 or 2, wherein the adhesive layer formed by crosslinking the adhesive composition has a surface resistivity of 1.0×10 ⁺¹² Ω/□ or less. The adhesive composition as described in item 1 or 2 of the scope of the patent application, wherein the (B) copolymerizable vinyl monomer containing hydroxyl and/or carboxyl is selected from copolymerizable monomers containing hydroxyl and carboxyl containing At least one or more of the group consisting of copolymerizable monomers, said hydroxyl-containing copolymerizable monomers are selected from (meth)acrylate-8-hydroxyoctyl, (meth)acrylate-6-hydroxyhexyl , (meth)acrylate-4-hydroxybutyl, (meth)acrylate-2-hydroxyethyl, N-hydroxy(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N -At least one of the compound group consisting of hydroxyethyl (meth)acrylamide, the carboxyl-containing copolymerizable monomer is selected from (meth)acrylic acid, carboxyl Ethyl(meth)acrylate, Carboxypentyl(meth)acrylate, 2-(meth)acryloxyethyl hexahydrophthalate, 2-(meth)acryloxypropyl Hexahydrophthalic acid, 2-(meth)acryloxyethylphthalic acid, 2-(meth)acryloxyethylsuccinic acid, 2-(meth)acryloxyethyl At least one or more of the compound group consisting of carboxypolycaprolactone mono(meth)acrylate and 2-(meth)acryloxyethyltetrahydrophthalic acid. An adhesive film, characterized in that an adhesive layer formed by cross-linking the adhesive composition described in any one of claims 1 to 4 of the patent claims is laminated on one side of the resin film. An optical film with an adhesive layer, which is formed by cross-linking the adhesive composition described in any one of items 1 to 4 of the scope of the patent application on at least one side of the optical film. agent layer. The adhesive film according to claim 5, wherein antistatic treatment and antifouling treatment are applied to one side of the resin film, that is, the side opposite to the side on which the adhesive layer is laminated. An adhesive film for a polarizer, which uses the adhesive film described in item 5 of the patent application. An adhesive film, characterized in that an adhesive layer formed by cross-linking the adhesive composition described in any one of claims 1 to 4 of the scope of the patent application is laminated on a separator with a thickness of 1 μm to 25 μm. The structure of release film/adhesive layer/release film formed on one side of the release film. A liquid crystal panel, characterized in that it uses the optical film with an adhesive layer as described in item 6 of the patent application.