JP2022039981A - Adhesive composition and optical film with adhesive layer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive composition for obtaining an optical film with an adhesive layer having excellent reworkability after being left in a humidified heat environment.
A pressure-sensitive adhesive composition contains a (meth) acrylic resin (A), a cross-linking agent (B), and a silane compound (C). The silane compound (C) contains a mercapto group-containing silane compound (C1) and an epoxy group-containing silane compound (C2). The content of the mercapto group-containing silane compound (C1) is higher than the content of the epoxy group-containing silane compound (C2).
[Selection diagram] None

Description

The present invention relates to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive layer, and an optical film with a pressure-sensitive adhesive layer.

A polarizing plate having a protective film laminated on at least one surface of a polarizing element is used in a liquid crystal display device, an organic electroluminescence (organic EL) display device, or the like. An optical film such as a polarizing plate is bonded to, for example, a liquid crystal cell of a liquid crystal display device or an organic EL element of an organic EL display device as an optical film with a pressure-sensitive adhesive layer having a pressure-sensitive adhesive layer laminated on at least one surface thereof. (For example, Patent Document 1 and the like).

In Patent Document 1, the silane coupling agent contained in the pressure-sensitive adhesive contains an epoxy group-containing silane coupling agent and a mercapto group-containing silane coupling agent, and the content of the epoxy group-containing silane coupling agent is mercapto. It is stated that the content of the group-containing silane coupling agent is the same as or greater than this.

Japanese Unexamined Patent Publication No. 2009-173877

However, Patent Document 1 does not describe that a pressure-sensitive adhesive containing an epoxy group-containing silane coupling agent and a mercapto group-containing silane coupling agent improves reworkability after being left in a humidified heat environment. ..

An object of the present invention is to provide an adhesive composition for obtaining an optical film with an adhesive layer having excellent reworkability after being left in a humidified heat environment.

The present invention provides the pressure-sensitive adhesive composition, the pressure-sensitive adhesive layer, and the optical film with the pressure-sensitive adhesive layer shown below.
[1] A pressure-sensitive adhesive composition containing a (meth) acrylic resin (A), a cross-linking agent (B), and a silane compound (C).
The silane compound (C) contains a mercapto group-containing silane compound (C1) and an epoxy group-containing silane compound (C2).
The pressure-sensitive adhesive composition having a content of the mercapto group-containing silane compound (C1) higher than that of the epoxy group-containing silane compound (C2).
[2] The (meth) acrylic resin (A) has a weight average molecular weight of 1 million or more, a glass transition temperature of −45 ° C. or higher, and a constituent unit derived from (meth) acrylate having a hydroxyl group. The pressure-sensitive adhesive composition according to [1], which is contained.
[3] The (meth) acrylic resin (A) further has a structural unit derived from the alkyl acrylate (a1) in which the glass transition temperature of the homopolymer is less than 0 ° C., and the glass transition temperature of the homopolymer is 0 ° C. The pressure-sensitive adhesive composition according to [1] or [2], which contains the above-mentioned structural unit derived from the alkyl acrylate (a2).
[4] The (meth) acrylic resin (A) further contains a structural unit derived from an unsaturated monomer having one olefinic double bond and at least one aromatic ring in the molecule. The pressure-sensitive adhesive composition according to any one of [1] to [3].
[5] The pressure-sensitive adhesive composition according to any one of [1] to [4], wherein the (meth) acrylic resin (A) further contains a structural unit derived from a carboxy group-containing (meth) acrylate.
[6] The cross-linking agent (B) contains an aromatic isocyanate cross-linking agent (B1).
The content of the aromatic isocyanate cross-linking agent (B1) is 0.1 part by mass or more and 4.5 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic resin (A) [1]. The pressure-sensitive adhesive composition according to any one of [5].
[7] The content of the mercapto group-containing silane compound (C1) is 0.1 part by mass or more and 8 parts by mass or less with respect to 100 parts by weight of the (meth) acrylic resin (A). [1] The pressure-sensitive adhesive composition according to any one of [6].
[8] The pressure-sensitive adhesive composition according to any one of [1] to [7], which further contains an ionic compound (D).
[9] A pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition according to any one of [1] to [8].
[10] An optical film with an adhesive layer, which comprises an optical film and the adhesive layer according to [9] laminated on at least one surface thereof.
[11] The optical film with an adhesive layer according to [10], wherein the optical film includes a polarizing element and a protective film laminated on at least one surface thereof.

According to the present invention, it is possible to provide an optical film with an adhesive layer having excellent reworkability after being left in a humidified heat environment.

It is a schematic sectional drawing schematically showing an example of the layer structure of the optical film with an adhesive layer which concerns on this invention. It is a schematic sectional drawing schematically showing another example of the layer structure of the optical film with an adhesive layer which concerns on this invention. It is a schematic sectional drawing schematically showing still another example of the layer structure of the optical film with an adhesive layer which concerns on this invention.

<Adhesive composition>
The pressure-sensitive adhesive composition according to the present invention contains a (meth) acrylic resin (A), a cross-linking agent (B), and a silane compound (C). In the pressure-sensitive adhesive composition, the silane compound (C) contains a mercapto group-containing silane compound (C1) and an epoxy group-containing silane compound (C2), and the content of the mercapto group-containing silane compound (C1) is the epoxy group-containing silane compound. It is higher than the content of (C2). The pressure-sensitive adhesive composition may further contain the ionic compound (D).

In the present specification, "(meth) acrylic" means acrylic and / or methacrylic, and the same applies to "(meth)" when referring to (meth) acrylate and the like.

According to the above, it is possible to obtain an adhesive composition for obtaining an optical film with an adhesive layer having excellent reworkability after being left in a humidified heat environment.
The reworkability after being left in a humidified heat environment is as described in the following Examples for a sample in which an optical film with an adhesive layer is attached to a glass substrate via the adhesive layer. The value of ii] can be suppressed to a certain level or less, and when the optical film with the adhesive layer is peeled off after the storage of the following [ii], fogging on the surface of the adherend and residual adhesive can be suppressed. The property that can be done. Further, it is preferable that the product has a property of suppressing the difference between the following [i] and [ii].
[I] Adhesive force between the adhesive layer and the adherend after being stored under normal conditions for a predetermined period [ii] Adhesive layer and adhesion after being stored for a predetermined period under predetermined humidifying heat conditions Adhesive force between the body

Hereinafter, each component contained in the pressure-sensitive adhesive composition will be described.
<(Meta) acrylic resin (A)>
The pressure-sensitive adhesive composition contains a (meth) acrylic resin (A) from the viewpoints of transparency, tackiness, reliability and the like. The (meth) acrylic resin (A) contained in the pressure-sensitive adhesive composition may be one kind or two or more kinds.

The (meth) acrylic resin (A) may contain a structural unit derived from (meth) acrylate having a weight average molecular weight of 1,000,000 or more, a glass transition temperature of −45 ° C. or higher, and a hydroxyl group. preferable.
The (meth) acrylic resin (A) preferably contains a structural unit derived from (meth) acrylic acid ester, a structural unit derived from (meth) acrylate having a hydroxyl group, and a constitution derived from (meth) acrylic acid ester. It may include other structural units other than the unit.
The inclusion of the (meth) acrylic resin (A) containing the above-mentioned structural unit in the pressure-sensitive adhesive composition is advantageous for improving the reworkability of the optical film with the pressure-sensitive adhesive layer after being left in a humidifying heat environment. obtain. Further, it may be advantageous to improve the durability of the optical film with the pressure-sensitive adhesive layer in the heat resistance test and the heat shock test.
Durability in the heat resistance test and the heat shock test means, as described in Examples described later, a glass substrate bonded via the pressure-sensitive adhesive layer of an optical film with a pressure-sensitive adhesive layer by the heat resistance test and the heat shock test. It refers to the property of being able to suppress problems such as floating and peeling at the interface with and foaming of the adhesive layer.

The weight average molecular weight (Mw) of the (meth) acrylic resin (A) is preferably 1 million or more, more preferably 1.2 million or more, and further preferably 1.2 million or more, from the viewpoint of durability in the heat resistance test and the heat shock test. It is preferably 1.4 million or more, particularly preferably 1.5 million or more, usually 2 million or less, 1.9 million or less, or 1.8 million or less.
The molecular weight distribution represented by the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) is usually 2 or more, preferably 3 or more, and more preferably 4 or more. Further, it is usually 10 or less, and may be 8 or less.
The weight average molecular weight (Mw) and the number average molecular weight (Mn) can be measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

The glass transition temperature of the (meth) acrylic resin (A) is preferably −45 ° C. or higher, more preferably −43 ° C. or higher, still more preferably -43 ° C. or higher, from the viewpoint of durability in the heat resistance test and the heat shock test. Is −42 ° C. or higher, usually −20 ° C. or lower, may be −25 ° C. or lower, or may be −30 ° C. or lower. The glass transition temperature can be measured by a differential scanning calorimeter (DSC).

[Constituent unit derived from (meth) acrylate having a hydroxyl group]
The (meth) acrylic resin (A) preferably contains a structural unit derived from (meth) acrylate having a hydroxyl group from the viewpoint of reactivity between the (meth) acrylic resin (A) and the cross-linking agent (B). ..

Examples of the (meth) acrylate having a hydroxyl group include 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 2- (2-hydroxyethoxy) ethyl (meth) acrylate. , 2- Or 3-Chloro-2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate and the like.
The (meth) acrylic resin (A) may contain only one type of structural unit derived from (meth) acrylate having a hydroxyl group, or may contain two or more types.

The content of the structural unit derived from the (meth) acrylate having a hydroxyl group is based on (meth) acrylic from the viewpoint of processability of the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition and adhesion between the pressure-sensitive adhesive layer and the optical film. Of all the constituent units constituting the resin (A), it is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and preferably 5% by mass or less, more preferably 4. It is less than mass%.

［式（Ｉ）中、
Ｒ^１は、水素原子又はメチル基を表し、
Ｒ^２は、炭素数１以上１０以下のアルコキシ基で置換されていてもよい炭素数１以上１４以下のアルキル基、又は炭素数１以上１０以下のアルコキシ基で置換されていてもよい炭素数７以上２１以下のアラルキル基を表す。］ [Constituent unit derived from (meth) acrylic acid ester]
The (meth) acrylic resin (A) is preferably a polymer containing a structural unit derived from the (meth) acrylic acid ester represented by the following formula (I) as a main component. The main component means that the content in all the constituent units constituting the (meth) acrylic resin is 50% by mass or more.

[In formula (I),
R ¹ represents a hydrogen atom or a methyl group.
^R2 may be substituted with an alkyl group having 1 or more and 14 or less carbon atoms which may be substituted with an alkoxy group having 1 or more and 10 or less carbon atoms, or 7 carbon atoms which may be substituted with an alkoxy group having 1 or more and 10 or less carbon atoms. Represents an alcoholic group of 21 or more and 21 or less. ]

In ^R2 , the carbon number of the aralkyl group when the aralkyl group is substituted with the alkoxy group is the carbon number excluding the carbon atom of the alkoxy group.
^R2 is preferably an alkyl group having 1 or more and 14 or less carbon atoms which may be substituted with an alkoxy group having 1 or more and 10 or less carbon atoms, and has 1 or more and 14 or less carbon atoms which are not substituted with the alkoxy group. It is more preferably an alkyl group.

Examples of the (meth) acrylic acid ester represented by the formula (I) include, for example.
Methyl (meth) acrylate, ethyl (meth) acrylate, n- and i-propyl (meth) acrylate, n- and i-butyl (meth) acrylate, n- and i-octyl (meth) acrylate, lauryl (meth) acrylate. Alkyl (meth) acrylate having a linear alkyl ester moiety such as;
Examples thereof include alkyl (meth) acrylate having a branched alkyl ester moiety such as isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isooctyl (meth) acrylate.

When R ² is an alkyl group substituted with an alkoxy group, that is, when R ² is an alkoxy alkyl group, the (meth) acrylic acid ester represented by the formula (I) is, for example, 2-methoxyethyl. Examples thereof include (meth) acrylate and ethoxymethyl (meth) acrylate.
Examples of the (meth) acrylic acid ester represented by the formula (I) when R ² is an aralkyl group having 7 or more and 21 or less carbon atoms include benzyl (meth) acrylate and the like.

The (meth) acrylic resin (A) may contain only one type of structural unit derived from the (meth) acrylic acid ester represented by the formula (I), or may contain two or more types. Above all, as the structural unit derived from the (meth) acrylic acid ester, it is preferable to include the structural unit derived from the (meth) acrylic acid alkyl ester.

The (meth) acrylic resin (A) is a structural unit derived from the alkyl acrylate (a1) in which the glass transition temperature of the homopolymer is less than 0 ° C. as a structural unit derived from the (meth) acrylic acid alkyl ester, and a homopolymer. It is preferable to contain a structural unit derived from the alkyl acrylate (a2) having a glass transition temperature of 0 ° C. or higher. By containing the (meth) acrylic resin (A) containing the structural units derived from the alkyl acrylates (a1) and (a2) in the pressure-sensitive adhesive composition, the reworkability after being left in a humidified heat environment is improved. It can be advantageous to obtain an optical film with an adhesive layer for the purpose. It can also be advantageous for improving durability in heat resistance tests and heat shock tests. For the Tg of the homopolymer of the alkyl acrylate, for example, literature values such as POLYMER HANDBOOK (Wiley-Interscience) can be adopted.

Examples of the alkyl acrylate (a1) include ethyl acrylate, n- and i-propyl acrylate, n- and i-butyl acrylate, n-pentyl acrylate, n- and i-hexyl acrylate, n-heptyl acrylate, n- and i. Examples thereof include alkyl acrylates having an alkyl group having about 2 to 12 carbon atoms such as octyl acrylate, 2-ethylhexyl acrylate, n- and i-nonyl acrylate, n- and i-decyl acrylate, and n-dodecyl acrylate.
As another specific example of the alkyl acrylate (a1), a substituent-containing alkyl acrylate in which a substituent is introduced into the alkyl group in an alkyl acrylate having an alkyl group having about 2 to 12 carbon atoms can be mentioned. The substituent of the substituent-containing alkyl acrylate is a group that substitutes the hydrogen atom of the alkyl group, and specific examples thereof include a phenyl group, an alkoxy group, and a phenoxy group. Specific examples of the substituent-containing alkyl acrylate include 2-methoxyethyl acrylate, ethoxymethyl acrylate, phenoxyethyl acrylate, and phenoxydiethylene glycol acrylate.
The alkyl group of the alkyl acrylate (a1) is preferably a linear or branched alkyl group.

As the alkyl acrylate (a1), only one kind may be used, or two or more kinds may be used in combination. Among them, the alkyl acrylate (a1) preferably contains one or more selected from ethyl acrylate, n-butyl acrylate, and 2-ethylhexyl acrylate. The alkyl acrylate (a1) preferably contains n-butyl acrylate from the viewpoint of reworkability after being left in a humidified heat environment and durability in a heat resistance test and a heat shock test.

The content of the structural unit derived from the alkyl acrylate (a1) in the (meth) acrylic resin (A) is from the viewpoint of reworkability after being left in a humidified heat environment, and from the viewpoint of durability in heat resistance test and heat shock test. Therefore, out of 100 parts by mass of all the constituent units constituting the (meth) acrylic resin (A), it is preferably 50 parts by mass or more, more preferably 55 parts by mass or more, and further preferably 60 parts by mass or more. Further, it is preferably 90 parts by mass or less, more preferably 85 parts by mass or less, and further preferably 81 parts by mass or less.

The alkyl acrylate (a2) is an alkyl acrylate other than the alkyl acrylate (a1). Examples of the alkyl acrylate (a2) include methyl acrylate, stearyl acrylate, t-butyl acrylate and the like.

As the alkyl acrylate (a2), only one kind may be used, or two or more kinds may be used in combination. Above all, the alkyl acrylate (a2) preferably contains a methyl acrylate from the viewpoint of reworkability after being left in a humidified heat environment and from the viewpoint of durability in a heat resistance test and a heat shock test.

The content of the structural unit derived from the alkyl acrylate (a2) in the (meth) acrylic resin (A) is from the viewpoint of reworkability after being left in a humidified heat environment, and from the viewpoint of durability in heat resistance test and heat shock test. Therefore, out of 100 parts by mass of all the constituent units constituting the (meth) acrylic resin (A), it is preferably 1 part by mass or more, more preferably 5 parts by mass or more, and further preferably 10 parts by mass or more. Further, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and further preferably 30 parts by mass or less.

The total content of the structural unit derived from the alkyl acrylate (a1) and the structural unit derived from the alkyl acrylate (a2) in the (meth) acrylic resin (A) is the total mass constituting the (meth) acrylic resin (A). In 100 parts by mass of the unit, it is preferably 60 parts by mass or more, more preferably 70 parts by mass or more, further preferably 80 parts by mass or more, and preferably 99.9 parts by mass or less, 99. It may be 5 parts by mass or less, or 99 parts by mass or less.

[Other monomers]
The (meth) acrylic resin (A) contains a structural unit derived from a (meth) acrylate having a hydroxyl group and a structural unit derived from a monomer other than the alkyl acrylates (a1) and (a2). Can be done. The (meth) acrylic resin (A) may contain only one type of structural unit derived from the other monomer, or may contain two or more types.

Other monomers include unsaturated monomers having one olefinic double bond and at least one aromatic ring in the molecule (however, the (meth) acrylate having the hydroxyl group and the above (I). (Excluding those corresponding to the (meth) acrylic acid ester represented by), contains a heterocyclic group such as a carboxy group-containing (meth) acrylate, a substituted or unsubstituted amino group-containing (meth) acrylate, and an epoxy group. Examples thereof include (meth) acrylates, styrene-based monomers, vinyl-based monomers, monomers having a plurality of (meth) acryloyl groups in the molecule, and (meth) acrylamide monomers.

The (meth) acrylic resin (A) contains, as other monomers, an unsaturated monomer having one olefinic double bond and at least one aromatic ring in the molecule, and a carboxy group. It is preferable to contain at least one of the (meth) acrylates, and more preferably to contain both.
Including one or both of these may be advantageous in improving the reworkability after being left in a humidified heat environment. It can also be advantageous for improving durability in heat resistance tests and heat shock tests.

［式（ＩＩ）中、
Ｒ^３は水素原子又はメチル基を表し、
ｎは１以上８以下の整数を表し、
Ｒ^４は水素原子、アルキル基、アラルキル基又はアリール基を表す。］ Examples of the unsaturated monomer having one olefinic double bond and at least one aromatic ring in the molecule include (meth) acrylic monomers having an aromatic ring.
Examples of the (meth) acrylic monomer having an aromatic ring include a (meth) acrylic acid ester having an aryloxyalkyl group such as a phenoxyethyl group-containing (meth) acrylic acid ester represented by the following formula (II). Examples thereof include neopentyl glycol benzoate (meth) acrylate.

[In formula (II),
R ³ represents a hydrogen atom or a methyl group.
n represents an integer of 1 or more and 8 or less.
^R4 represents a hydrogen atom, an alkyl group, an aralkyl group or an aryl group. ]

When R ⁴ is an alkyl group, its carbon number can be about 1 or more and 9 or less, when it is an aralkyl group, its carbon number is about 7 or more and 11 or less, and when it is an aryl group, its carbon number is about 1. Can be 6 or more and 10 or less.

In the formula (II), the alkyl group having 1 or more and 9 or less carbon atoms constituting R ⁴ includes a methyl group, a butyl group and a nonyl group, and the aralkyl group having 7 or more and 11 or less carbon atoms includes a benzyl group and a phenethyl group. Examples of the aryl group having a group, a naphthylmethyl group and the like having 6 or more and 10 or less carbon atoms include a phenyl group, a trill group and a naphthyl group, respectively.

Specific examples of the phenoxyethyl group-containing (meth) acrylic acid ester represented by the formula (II) include (meth) acrylic acid 2-phenoxyethyl and (meth) acrylic acid 2- (2-phenoxyethoxy) ethyl. , (Meta) acrylic acid ester of ethylene oxide-modified nonylphenol, 2- (o-phenylphenoxy) ethyl (meth) acrylic acid, and the like.
As the phenoxyethyl group-containing (meth) acrylic acid ester, only one type may be used alone, or two or more types may be used in combination.
Among them, the (meth) acrylic acid ester containing a phenoxyethyl group includes (meth) acrylic acid 2-phenoxyethyl, (meth) acrylic acid 2- (o-phenylphenoxy) ethyl and (meth) acrylic acid 2- (2-phenoxy). It preferably contains one or more selected from the group consisting of ethoxy) ethyl, preferably 2- (o-phenylphenoxy) ethyl (meth) acrylate and 2- (2-phenoxyethoxy) (meth) acrylate. It is more preferable to include one or two selected from the group consisting of ethyl.

The content of the structural unit derived from the unsaturated monomer having one olefinic double bond and at least one aromatic ring in the molecule of the (meth) acrylic resin (A) is the (meth) acrylic resin. Of all the constituent units constituting the resin (A), it may be 1 part by mass or more, 3 parts by mass or more, 5 parts by mass or more, and usually 20 parts by mass or less. It is preferably 15 parts by mass or less, and more preferably 10 parts by mass or less.

Examples of the carboxy group-containing (meth) acrylate include (meth) acrylic acid and carboxyethyl (meth) acrylate.
The content of the carboxy group-containing (meth) acrylate-derived structural unit in the (meth) acrylic resin (A) is preferably 2% by mass based on 100 parts by mass of all the structural units constituting the (meth) acrylic resin (A). It is 5 parts or less, more preferably 1.5 parts by mass or less, further preferably 1 part by mass or less, usually 0.01 parts by mass or more, and may be 0.05 parts by mass or more.

Examples of the (meth) acrylate containing a substituted or unsubstituted amino group include aminoethyl (meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, and dimethylaminopropyl (meth) acrylate.
The content of the constituent unit derived from the (meth) acrylate containing the substituted or unsubstituted amino group is preferably 2 parts by mass or less in 100 parts by mass of all the constituent units constituting the (meth) acrylic resin (A). , More preferably 1.5 parts by mass or less, further preferably 1 part by mass or less, usually 0.01 parts by mass or more, and may be 0.05 parts by mass or more.

Examples of the (meth) acrylate containing a heterocyclic group include acryloylmorpholine, vinylcaprolactone, N-vinyl-2-pyrrolidone, vinylpyridine, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, and 3,4-epoxy. Examples thereof include cyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, and 2,5-dihydrofuran.
The content of the structural unit derived from the (meth) acrylate containing the heterocyclic group is preferably 2 parts by mass or less, more preferably 2 parts by mass or less, out of 100 parts by mass of all the structural units constituting the (meth) acrylic resin (A). Is 1.5 parts by mass or less, more preferably 1 part by mass or less, usually 0.01 parts by mass or more, and may be 0.05 parts by mass or more.

Examples of the styrene-based monomer include styrene; methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, octylstyrene and other alkylstyrenes; fluorostyrene, Halogenized styrene such as chlorostyrene, bromostyrene, dibromostyrene, iodostyrene; nitrostyrene, acetylstyrene, methoxystyrene, divinylbenzene and the like can be mentioned.

Examples of the vinyl-based monomer include fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate and vinyl laurate; vinyl halides such as vinyl chloride and vinyl bromide; vinylidene chloride and the like. Vinylidene halide; nitrogen-containing aromatic vinyl such as vinylpyridine, vinylpyrrolidone, vinylcarbazole and the like; conjugated diene monomers such as butadiene, isoprene and chloroprene; acrylonitrile, methacrylonitrile and the like can be mentioned.

Examples of the monomer having a plurality of (meth) acryloyl groups in the molecule include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 1,9-nonanediol di (. Two (meth) acryloyl groups in molecules such as meta) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and tripropylene glycol di (meth) acrylate. Monomer having; Examples thereof include a monomer having three (meth) acryloyl groups in a molecule such as trimethylolpropanetri (meth) acrylate.

Examples of the (meth) acrylamide monomer include N-methylol (meth) acrylamide, N- (2-hydroxyethyl) (meth) acrylamide, N- (3-hydroxypropyl) (meth) acrylamide, and N- (4-hydroxy). Butyl) (meth) acrylamide, N- (5-hydroxypentyl) (meth) acrylamide, N- (6-hydroxyhexyl) (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) ) Acrylamide, N-isopropyl (meth) acrylamide, N- (3-dimethylaminopropyl) (meth) acrylamide, N- (1,1-dimethyl-3-oxobutyl) (meth) acrylamide, N- [2- (2) -Oxo-1-imidazolidinyl) ethyl] (meth) acrylamide, 2-acrylloylamino-2-methyl-1-propanesulfonic acid, N- (methoxymethyl) acrylamide, N- (ethoxymethyl) (meth) acrylamide, N- (Propoxymethyl) (meth) acrylamide, N- (1-methylethoxymethyl) (meth) acrylamide, N- (1-methylpropoxymethyl) (meth) acrylamide, N- (2-methylpropoxymethyl) (meth) acrylamide [Also known as: N- (isobutoxymethyl) (meth) acrylamide], N- (butoxymethyl) (meth) acrylamide, N- (1,1-dimethylethoxymethyl) (meth) acrylamide, N- (2-methoxyethyl) ) (Meta) acrylamide, N- (2-ethoxyethyl) (meth) acrylamide, N- (2-propoxyethyl) (meth) acrylamide, N- [2- (1-methylethoxy) ethyl] (meth) acrylamide, N- [2- (1-methylpropoxy) ethyl] (meth) acrylamide, N- [2- (2-methylpropoxy) ethyl] (meth) acrylamide [also known as: N- (2-isobutoxyethyl) (meth) Acrylamide], N- (2-butoxyethyl) (meth) acrylamide, N- [2- (1,1-dimethylethoxy) ethyl] (meth) acrylamide and the like. Of these, N- (methoxymethyl) acrylamide, N- (ethoxymethyl) acrylamide, N- (propoxymethyl) acrylamide, N- (butoxymethyl) acrylamide, and N- (2-methylpropoxymethyl) acrylamide are preferably used.

It is preferable that the (meth) acrylic resin (A) does not substantially contain a structural unit derived from a (meth) acrylic acid ester having an alicyclic structure in the molecule. The fact that the constituent unit is not substantially contained means that the content of the constituent unit derived from the (meth) acrylic acid ester having an alicyclic structure in the molecule constitutes the (meth) acrylic resin (A). It means that it is 0.5 parts by mass or less in 100 parts by mass of all the constituent units, and the content may be 0.1 parts by mass or less, 0.05 parts by mass or less, and 0. It may be 01 parts by mass or less.

The alicyclic structure in a (meth) acrylic acid ester having an alicyclic structure in a molecule is a cycloparaffin structure having a carbon number of usually 5 or more, for example, 5 or more and 12 or less.
Examples of the (meth) acrylic acid ester having an alicyclic structure include (meth) acrylate isobornyl, (meth) acrylate cyclohexyl, (meth) acrylate dicyclopentanyl, (meth) acrylate cyclododecyl, and (meth). Examples thereof include methylcyclohexyl acrylate, trimethylcyclohexyl (meth) acrylate, t-butylcyclohexyl (meth) acrylate, cyclohexylphenyl (meth) acrylate, cyclohexyl α-ethoxyacrylate and the like.

[Manufacturing of (meth) acrylic resin (A)]
The (meth) acrylic resin (A) can be produced by a known method such as a solution polymerization method, a bulk polymerization method, a suspension polymerization method, or an emulsion polymerization method. In the production of the (meth) acrylic resin (A), a polymerization initiator is usually used. The polymerization initiator can be used in an amount of 0.001 part by mass or more and 5 parts by mass or less with respect to a total of 100 parts by mass of all the monomers used in the production of the (meth) acrylic resin (A). Further, the (meth) acrylic resin (A) may be produced by a method of advancing the polymerization with active energy rays such as ultraviolet rays.

As the polymerization initiator, a thermal polymerization initiator, a photopolymerization initiator, or the like is used.
Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone.
Examples of the thermal polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2-methylbutyronitrile), and 1,1'-azobis (cyclohexane-1-carbonitrile). , 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl-2,2'-azobis (2-methylpro) Pionate), azo compounds such as 2,2'-azobis (2-hydroxymethylpropionitrile); lauryl peroxide, tert-butylhydroperoxide, benzoyl peroxide, tert-butylperoxybenzoate, cumenehydroper Organic compounds such as oxide, diisopropylperoxydicarbonate, dipropylperoxydicarbonate, tert-butylperoxyneodecanoate, tert-butylperoxypivalate, (3,5,5-trimethylhexanoyl) peroxide. Oxides: Inorganic peroxides such as potassium persulfate, ammonium persulfate, hydrogen peroxide and the like can be mentioned.
Further, a redox-based initiator or the like in which a peroxide and a reducing agent are used in combination can also be used as the polymerization initiator.

As a method for producing the (meth) acrylic resin (A), the solution polymerization method is preferable among the methods shown above. As an example of the solution polymerization method, the monomer and the organic solvent to be used are mixed, a thermal polymerization initiator is added under a nitrogen atmosphere, and the temperature is 40 ° C. or higher and 90 ° C. or lower, preferably 50 ° C. or higher and 80 ° C. or lower. Stir for 3 hours or more and 15 hours or less. In order to control the reaction, the monomer or the thermal polymerization initiator may be added continuously or intermittently during the polymerization, or may be added in a state of being dissolved in an organic solvent.
Examples of the organic solvent include aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; aliphatic alcohols such as propyl alcohol and isopropyl alcohol; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone. Kind and the like.

<Crosslinking agent (B)>
The pressure-sensitive adhesive composition contains a cross-linking agent (B). The cross-linking agent (B) reacts with polar functional groups (hydroxyl group, carboxy group, amino group, heterocyclic group, amide group) and the like in the (meth) acrylic resin (A), and the (meth) acrylic resin (A). ) Is a compound that crosslinks. By using the cross-linking agent (B), the adhesion and heat resistance between the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition and the optical film can be improved.
Examples of the cross-linking agent (B) include a cross-linking agent selected from an isocyanate-based cross-linking agent, an epoxy-based cross-linking agent, an aziridine-based cross-linking agent, a metal chelate-based cross-linking agent, and the like. The cross-linking agent (B) preferably contains an isocyanate-based cross-linking agent, and more preferably contains an aromatic isocyanate-based cross-linking agent (B1).
As the cross-linking agent (B), only one type may be used alone, or two or more types may be used in combination.

The isocyanate-based cross-linking agent is a compound having at least two isocyanato groups (-NCO) in the molecule.
Examples of the isocyanate-based cross-linking agent include hexamethylene diisocyanate, isophorone diisocyanate, and aromatic isocyanate cross-linking agent (B1). The aromatic isocyanate cross-linking agent (B1) is a compound having at least one aromatic ring and at least two isocyanato groups (-NCO) in the molecule.
The pressure-sensitive adhesive composition preferably contains an aromatic isocyanate cross-linking agent (B1).

Examples of the aromatic isocyanate cross-linking agent (B) include tolylene diisocyanate, chlorphenylenedi isocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, polymethylene polyphenyl isocyanate, naphthalene diisocyanate, and triphenylmethane. Examples thereof include triisocyanate.
The aromatic isocyanate cross-linking agent (B) includes polyhydric alcohol compound adducts (adducts) of these isocyanate compounds (for example, adducts made of glycerol, trimethylolpropane, etc.), isocyanurates, bullet-type compounds, and polyethers. It may be a derivative of a urethane prepolymer type isocyanate compound or the like which has been subjected to an addition reaction with a polyol, a polyester polyol, an acrylic polyol, a polybutadiene polyol, a polyisoprene polyol or the like.
As the aromatic isocyanate cross-linking agent (B), only one type may be used alone, or two or more types may be used in combination.

The content of the aromatic isocyanate cross-linking agent (B) is 0.1 part by mass or more, and may be 0.5 part by mass or more, based on 100 parts by mass of the (meth) acrylic resin (A). It may be 1 part by mass or more. The content of the aromatic isocyanate cross-linking agent (B) is 4.5 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic resin (A), and may be 4 parts by mass or less, or 3 parts by mass. It may be less than or equal to a part. When the content of the aromatic isocyanate cross-linking agent (B) is within the above range, good durability in the heat resistance test and the heat shock test can be obtained.

An epoxy-based crosslinker is a compound having at least two epoxy groups in the molecule.
Examples of the epoxy-based cross-linking agent include bisphenol A type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, and trimethylol. Propanetriglycidyl ether, N, N-diglycidyl aniline, N, N, N', N'-tetraglycidyl-m-xylenediamine, 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane, etc. Can be mentioned.
As the epoxy-based cross-linking agent, only one type may be used alone, or two or more types may be mixed and used.

The aziridine-based cross-linking agent is a compound also called ethyleneimine, which has at least two skeletons of a three-membered ring composed of one nitrogen atom and two carbon atoms in the molecule.
Examples of the aziridine-based cross-linking agent include diphenylmethane-4,4'-bis (1-aziridinecarboxamide), toluene-2,4-bis (1-aziridinecarboxamide), triethylenemelamine, and isophthaloylbis-1- (2). -Methylaziridine), Tris-1-aziridinylphosphine oxide, hexamethylene-1,6-bis (1-aziridinecarboxamide), trimethylolpropane-tris-β-aziridinylpropionate, tetramethylolmethane-tris -Β-aziridinyl propionate and the like can be mentioned.
As the aziridine-based cross-linking agent, only one type may be used alone, or two or more types may be mixed and used.

Examples of the metal chelate-based cross-linking agent include compounds in which acetylacetone or ethyl acetoacetate is coordinated with a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium. And so on.
It is also possible to use a mixture of two or more kinds of metal chelate-based cross-linking agents.

The content of the cross-linking agent (B) in the pressure-sensitive adhesive composition is usually 5 parts by mass or less, preferably 2 parts by mass or less, based on 100 parts by mass of the (meth) acrylic resin (A). The content of the cross-linking agent (B) in the pressure-sensitive adhesive composition is usually 0.05 parts by mass or more and 0.1 parts by mass or more with respect to 100 parts by mass of the (meth) acrylic resin (A). May be good.

<Silane compound (C)>
The pressure-sensitive adhesive composition contains a silane compound (C), and the silane compound (C) contains a mercapto group-containing silane compound (C1) and an epoxy group-containing silane compound (C2).
In the pressure-sensitive adhesive composition, the content of the mercapto group-containing silane compound (C1) is higher than the content of the epoxy group-containing silane compound (C2). This makes it possible to improve the reworkability of the pressure-sensitive adhesive composition containing the mercapto group-containing silane compound (C1) and the epoxy group-containing silane compound (C2) after being left in a humidified heat environment.
The pressure-sensitive adhesive composition may contain other silane compounds other than the mercapto group-containing silane compound (C1) and the epoxy group-containing silane compound (C2).

The total content of the mercapto group-containing silane compound (C1) and the epoxy group-containing silane compound (C2) in the pressure-sensitive adhesive composition is 0.1 with respect to 100 parts by mass of the (meth) acrylic resin (A). It is 5 parts by mass or more, may be 0.3 parts by mass or more, may be 1 part by mass or more, may be 3 parts by mass or more, and may be 8 parts by mass or less, 7.5 parts by mass. It may be less than or equal to 6 parts by mass, and may be less than or equal to 6 parts by mass.

[Mercapt group-containing silane compound (C1)]
The mercapto group-containing silane compound (C1) is an organic silicon compound having at least one mercapto group (organic group containing a mercapto group) and at least one alkoxysilyl group in the molecule.

Specific examples of the mercapto group-containing silane compound (C1) include
Mercapto group-containing low molecular weight silane compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, and 3-mercaptopropyldimethoxymethylsilane;
Mercapto group-containing silane compounds such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyldimethoxymethylsilane, and methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxysilane, ethyltrimethoxy Examples thereof include a mercapto group-containing oligomer-type silane compound such as a cocondensate with an alkyl group-containing silane compound such as silane.
Examples of the mercapto group-containing oligomer-type silane compound include, for example.
3-Mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer,
3-Mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer,
3-Mercaptopropyltriethoxysilane-tetramethoxysilane copolymer,
Copolymers containing mercaptopropyl groups such as 3-mercaptopropyltriethoxysilane-tetraethoxysilane copolymer;
Mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer,
Mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer,
Mercaptomethyltriethoxysilane-tetramethoxysilane copolymer,
Examples thereof include copolymers containing a mercaptomethyl group such as a mercaptomethyltriethoxysilane-tetraethoxysilane copolymer.

As the mercapto group-containing silane compound (C1), a mercapto group-containing oligomer-type silane compound is preferable, and a mercapto group-containing silane compound and an alkyl group-containing silane compound are particularly preferable from the viewpoint of improving the reworkability after being left in a humidified heat environment. The cocondensate of 3-mercaptopropyltrimethoxysilane and methyltriethoxysilane is preferable.
The molecular weight of the mercapto group-containing silane compound (C1) may be 200 or more, 500 or more, or 1000 or more. The molecular weight of the mercapto group-containing silane compound (C1) may be 30,000 or less, 20,000 or less, or 10,000 or less. Since the molecular weight of the mercapto group-containing silane compound (C1) is within the above range, the mercapto group-containing silane compound (C1) volatilizes when the solvent-containing pressure-sensitive adhesive composition described later is applied onto a film and dried. Can be suppressed and the reworkability after being left in a humidified heat environment can be improved.
The mercapto equivalent of the mercapto group-containing silane compound (C1) may be 200 g / mol or more, or 300 g / mol or more. The mercapto equivalent of the mercapto group-containing silane compound (C1) may be 1000 g / mol or less, or may be 850 g / mol or less. When the mercapto equivalent of the mercapto group-containing silane compound (C1) is within the above range, the reworkability after being left in a humidified heat environment can be improved.
These may be used individually by 1 type and may be used in combination of 2 or more type.

The content of the mercapto group-containing silane compound (C1) may be 0.1 part by mass or more, or 0.3 part by mass or more with respect to 100 parts by mass of the (meth) acrylic resin (A). It may be 1 part by mass or more, or 3 parts by mass or more. The content of the mercapto group-containing silane compound (C1) may be 8 parts by mass or less, or 7.5 parts by mass or less, based on 100 parts by mass of the (meth) acrylic resin (A). It may be 6 parts by mass or less. When the content of the mercapto group-containing silane compound (C1) is within the above range, the reworkability after being left in a humidified heat environment can be improved.

The content of the mercapto group-containing silane compound (C1) is not particularly limited as long as it is larger than the content of the epoxy group-containing silane compound (C2). The content of the mercapto group-containing silane compound (C1) may be more than 1 times, 1.5 times or more, or 2 times or more the content of the epoxy group-containing silane compound (C2). It may be 5 times or more, more preferably 7 times or more, and usually 20 times or less, and may be 15 times or less.

[Epoxy group-containing silane compound (C2)]
The epoxy group-containing silane compound (C2) is an organic silicon compound having at least one epoxy group (organic group containing an epoxy group) and at least one alkoxysilyl group in the molecule.

Specific examples of the epoxy group-containing silane compound (C2) include
3-glycidoxypropyltrialkoxysilanes such as 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropyltriethoxysilane;
3-glycidoxypropylalkyldialkoxysilanes such as 3-glycidoxypropylmethyldiethoxysilane and 3-glycidoxypropylmethyldimethoxysilane;
2- (3,4-Epoxycyclohexyl) ethyltrialkoxy such as methyltri (glycidyl) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane Examples include silane.
The epoxy group-containing silane compound (C2) may be of the silicone oligomer type. Examples of the oligomer-type epoxy group-containing silane compound (C2) include, for example.
3-Glydoxypropyltrimethoxysilane-tetramethoxysilane copolymer,
3-Glydoxypropyltrimethoxysilane-tetraethoxysilane copolymer,
3-Glydoxypropyltriethoxysilane-tetramethoxysilane copolymer,
3-Glydoxypropyltriethoxysilane-tetraethoxysilane copolymer,
3-Glydoxypropylmethyldimethoxysilane-tetramethoxysilane copolymer,
3-Glydoxypropylmethyldimethoxysilane-tetraethoxysilane copolymer,
3-Glydoxypropylmethyldiethoxysilane-tetramethoxysilane copolymer,
Examples thereof include copolymers containing a 3-glycidoxypropyl group such as 3-glycidoxypropylmethyldiethoxysilane-tetraethoxysilane copolymer.

Above all, from the viewpoint of improving the reworkability after being left in a humidified heat environment, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2 -(3,4 epoxycyclohexyl) ethyltrimethoxysilane is preferable, and 3-glycidoxypropyltrimethoxysilane is particularly preferable.
The epoxy group-containing silane compound (C2) may be used alone or in combination of two or more.

The content of the epoxy group-containing silane compound (C2) may be 0.01 part by mass or more, or 0.05 part by mass or more with respect to 100 parts by mass of the (meth) acrylic resin (A). It may be 0.1 parts by mass or more. The content of the mercapto group-containing silane compound (C1) may be 5 parts by mass or less, 3 parts by mass or less, or 1 part by mass with respect to 100 parts by mass of the (meth) acrylic resin (A). It may be less than or equal to a part. When the content of the epoxy group-containing silane compound (C2) is within the above range, the reworkability after being left in a humidified heat environment can be improved.

The content of the epoxy group-containing silane compound (C2) is not particularly limited as long as it is smaller than the content of the mercapto group-containing silane compound (C1). The content of the mercapto group-containing silane compound (C1) may be 0.8 times or less, 0.6 times or less, or 0.5 times the content of the epoxy group-containing silane compound (C2). It is preferably fold or less, usually 0.05 times or more, and may be 0.1 times or more.

[Other silane compounds]
The pressure-sensitive adhesive composition may contain one or more silane compounds other than the mercapto group-containing silane compound (C1) and the epoxy group-containing silane compound (C2).
Examples of other silane compounds include acryloyl-based silane compounds, hydroxyl group-based silane compounds, carboxy-based silane compounds, amino-based silane compounds, amide-based silane compounds, and isocyanate-based silane compounds.

<Ionic compound (D)>
The pressure-sensitive adhesive composition may contain an ionic compound (D). The ionic compound (D) can be used as an antistatic agent for imparting antistatic properties to the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition. The ionic compound (D) is a compound having an inorganic cation or an organic cation and an inorganic anion or an organic anion.
The ionic compound (D) contained in the pressure-sensitive adhesive composition may be one kind or two or more kinds.

Examples of the inorganic cation include alkali metal ions such as lithium cation [Li ⁺ ], sodium cation [Na ⁺ ], potassium cation [K ⁺ ]; beryllium cation [Be ²⁺ ], magnesium cation [Mg ²⁺ ], calcium cation [ Examples include alkaline earth metal ions such as Ca ²⁺ ].

Examples of the organic cation include imidazolium cation, pyridinium cation, pyroridinium cation, ammonium cation, sulfonium cation, phosphonium cation and the like.

Of the above-mentioned cationic components, the organic cationic component is preferably used because it has excellent compatibility with the pressure-sensitive adhesive composition. Among the organic cation components, the pyridinium cation and the imidazolium cation are preferably used from the viewpoint that they are not easily charged when the separate film provided on the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition is peeled off.

Examples of the inorganic anion include chloride anion [ ^Cl- ], bromide anion [Br- ^] , iodide anion [I- ^] , tetrachloroaluminate anion [AlCl _4- ^] , and heptachlorodialuminate anion [Al ₂ Cl]. _7- ^] , tetrafluoroborate anion [BF _4- ^] , hexafluorophosphate anion [PF _6- ^] , perclorate anion [ClO _4- ^] , nitrate anion [NO _3- ^] , hexafluoroarsenate anion [AsF ₆ ]. ^- ], Hexafluoroantimonate anion [SbF _6- ^] , Hexafluoroniobate anion [NbF _6- ^] , Hexafluorotantalate anion [TaF _6- ^] , Disyanamide anion [(CN) _2N- ^] , Hexafluoro Phosphate anion [PF _6- ^{] and} the like can be mentioned.

Examples of the organic anion include acetate anion [CH ₃ COO- ^] , trifluoroacetate anion [CF ₃ COO- ^] , methanesulfonate anion [CH ₃ SO _3- ^] , trifluoromethanesulfonate anion [CF ₃ SO _3- ^] , and the like. p-Toluene sulfonate anion [p-CH ₃ C ₆ H ₄ SO _3- ^] , bis (fluorosulfonyl) imide anion [(FSO ₂ ) ₂ N- ^] , bis (trifluoromethanesulfonyl) imide anion [(CF ₃ SO ₂ ) ) ₂ N- ^] , Tris (trifluoromethanesulfonyl) methanide anion [(CF ₃ SO ₂ ) ₃ C- ^] , dimethylphosphinate anion [(CH ₃ ) ₂ POO- ^] , (poly) hydrofluorofluoride anion [ F (HF) _m- ^] (m is 1 or more and 3 or less), thiosian anion ^[ SCN-], perfluorobutane sulfonate anion [ _C4 F ₉ SO _3- ^] , bis (pentafluoroethanesulfonyl) imide anion [() C ₂ F ₅ SO ₂ ) ₂ N- ^] , perfluorobutanoate anion [C ₃ F ₇ COO- ^] , (trifluoromethanesulfonyl) (trifluoromethanecarbonyl) imide anion [(CF ₃ SO ₂ ) (CF ₃ CO) ) N- ^] , perfluoropropane-1,3-disulfonate anion ^[ -O ₃ S (CF ₂ ) ₃ SO _3- ^] , carbonate anion [CO ₃ ^2- ] and the like.

Among the above-mentioned anionic components, the anionic component containing a fluorine atom is preferably used because it gives an ionic compound (D) having excellent antistatic performance. Examples of the anion component containing a fluorine atom include hexafluorophosphate anion, bis (fluorosulfonyl) imide anion, hexafluorophosphate anion, and bis (trifluoromethanesulfonyl) imide anion.

Specific examples of the ionic compound (D) can be selected from the combination of the above-mentioned cationic component and anionic component. Examples of ionic compounds having organic cations are shown below, classified according to the structure of the organic cations.

Pyridinium salt:
N-hexylpyridinium hexafluorophosphate,
N-hexyl-4-methylpyridinium hexafluorophosphate,
N-octylpyridinium hexafluorophosphate,
N-octyl-4-methylpyridinium hexafluorophosphate,
N-Butyl-4-methylpyridinium hexafluorophosphate,
N-decylpyridinium bis (fluorosulfonyl) imide,
N-dodecylpyridinium bis (fluorosulfonyl) imide,
N-Tetradecylpyridinium bis (fluorosulfonyl) imide,
N-Hexadecylpyridinium bis (fluorosulfonyl) imide,
N-dodecyl-4-methylpyridinium bis (fluorosulfonyl) imide,
N-Tetradecyl-4-methylpyridinium bis (fluorosulfonyl) imide,
N-Hexadecyl-4-methylpyridinium bis (fluorosulfonyl) imide,
N-Benzyl-2-methylpyridinium bis (fluorosulfonyl) imide,
N-Benzyl-4-methylpyridinium bis (fluorosulfonyl) imide,
N-hexylpyridinium bis (trifluoromethanesulfonyl) imide,
N-octylpyridinium bis (trifluoromethanesulfonyl) imide,
N-octyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide,
N-Butyl-4-methylpyridinium bis (trifluoromethanesulfonyl) imide.

Imidazole salt:
1-Ethyl-3-methylimidazolium hexafluorophosphate,
1-Ethyl-3-methylimidazolium p-toluenesulfonate,
1-Ethyl-3-methylimidazolium bis (fluorosulfonyl) imide,
1-Ethyl-3-methylimidazolium bis (trifluoromethanesulfonyl) imide,
1-Butyl-3-methylimidazolium methanesulfonate,
1-Butyl-3-methylimidazolium bis (fluorosulfonyl) imide.

Pyrrolidinium salt:
N-Butyl-N-Methylpyrrolidinium Hexafluorophosphate,
N-Butyl-N-Methylpyrrolidinium bis (fluorosulfonyl) imide,
N-Butyl-N-Methylpyrrolidinium bis (trifluoromethanesulfonyl) imide.

Quaternary ammonium salt:
Tetrabutylammonium hexafluorophosphate,
Tetrabutylammonium p-toluenesulfonate,
(2-Hydroxyethyl) trimethylammonium bis (trifluoromethanesulfonyl) imide,
(2-Hydroxyethyl) trimethylammonium dimethylphosphinate.

Examples of ionic compounds having inorganic cations are shown below.

Lithium bromide,
Lithium iodide,
Lithium tetrafluoroborate,
Lithium hexafluorophosphate,
Lithium isothiocyanate,
Lithium perchlorate,
Lithium trifluoromethanesulfonate,
Lithium bis (fluorosulfonyl) imide,
Lithium bis (trifluoromethanesulfonyl) imide,
Lithium bis (pentafluoroethanesulfonyl) imide,
Lithium Tris (Trifluoromethanesulfonyl) Metanide,
Lithium p-toluenesulfonate,
Sodium hexafluorophosphate,
Sodium bis (fluorosulfonyl) imide,
Sodium bis (trifluoromethanesulfonyl) imide,
Sodium p-toluenesulfonate,
Potassium hexafluorophosphate,
Potassium bis (fluorosulfonyl) imide,
Potassium bis (trifluoromethanesulfonyl) imide,
Potassium p-toluenesulfonate.

The ionic compound (D) is preferably solid at room temperature. According to the ionic compound (D) which is solid at room temperature, the antistatic performance can be maintained for a long period of time as compared with the case where the ionic compound (D) which is liquid at room temperature is used. From the viewpoint of long-term stability of antistatic property, the ionic compound preferably has a melting point of 30 ° C. or higher, more preferably 35 ° C. or higher. On the other hand, if the melting point is too high, the compatibility with the (meth) acrylic resin (A) deteriorates, so that the melting point of the ionic compound (D) is preferably 90 ° C. or lower, more preferably 70 ° C. or less. Below, it is more preferably less than 50 ° C.

The content of the ionic compound (D) in the pressure-sensitive adhesive composition is preferably 0.1 part by mass or more, more preferably 0.2 part by mass or more with respect to 100 parts by mass of the (meth) acrylic resin (A). It is more preferably 0.3 parts by mass or more, particularly preferably 1 part by mass or more, and preferably 10 parts by mass or less, more preferably 9 parts by mass or less, still more preferably 8 parts by mass or less.
The content of the ionic compound (D) within the above range is advantageous for improving the antistatic performance of the pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition.

<Other ingredients>
The pressure-sensitive adhesive composition may contain other components other than the (meth) acrylic resin (A), the cross-linking agent (B), the silane compound (C), and the ionic compound (D) described above.
Other components include resins other than (meth) acrylic resin (A), cross-linking catalysts, weather-resistant stabilizers, tack fires, plasticizers, softeners, dyes, pigments, inorganic fillers, and additives such as light-scattering fine particles. Can be contained.
In addition, an ultraviolet curable compound may be added to the pressure-sensitive adhesive composition to form a pressure-sensitive adhesive layer and then irradiated with ultraviolet rays to cure the pressure-sensitive adhesive layer, thereby forming a harder pressure-sensitive adhesive layer.

<Adhesive layer>
The pressure-sensitive adhesive layer according to the present invention contains the above-mentioned pressure-sensitive adhesive composition. The pressure-sensitive adhesive layer is obtained by dissolving or dispersing each component constituting the pressure-sensitive adhesive composition in a solvent to obtain a solvent-containing pressure-sensitive adhesive composition, and then applying the pressure-sensitive adhesive layer onto a base film or an optical film and drying the pressure-sensitive adhesive layer. be able to.
Examples of the solvent include organic solvents exemplified in the production of the above (meth) acrylic resin.

The base film is generally a thermoplastic resin film, and a typical example thereof is a separate film that has been subjected to a mold release treatment. Examples of the separate film include those in which the surface on which the pressure-sensitive adhesive layer of the film made of a resin such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and polyarate is formed is subjected to a mold release treatment such as silicone treatment.
For example, the pressure-sensitive adhesive sheet obtained by directly applying the pressure-sensitive adhesive composition to the release-treated surface of the separate film to form the pressure-sensitive adhesive layer may be laminated on an optical film or the like. The pressure-sensitive adhesive sheet may have another separate film laminated on the side opposite to the separate film of the pressure-sensitive adhesive layer. When the pressure-sensitive adhesive sheet has separate films on both sides of the pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer exposed by peeling off one of the separate films may be attached to an optical film or the like.

When the pressure-sensitive adhesive layer is provided on the surface of the optical film, it is preferable to perform surface activation treatment, for example, plasma treatment, corona treatment, etc. on the bonding surface of the optical film and / or the bonding surface of the pressure-sensitive adhesive layer. It is more preferable to apply the treatment.

The thickness of the pressure-sensitive adhesive layer is preferably 5 μm or more, more preferably 10 μm or more, still more preferably 15 μm or more, and preferably 45 μm or less, more preferably 30 μm or less, still more preferably 25 μm or less. When the thickness of the pressure-sensitive adhesive layer is within the above range, it may be advantageous in suppressing the deterioration of the adhesiveness with time.

<Optical film with adhesive layer>
1 to 3 are schematic cross-sectional views schematically showing an example of the layer structure of the optical film with an adhesive layer according to the present invention. As shown in FIGS. 1 to 3, the optical film 1 with a pressure-sensitive adhesive layer includes an optical film 10 and a pressure-sensitive adhesive layer 20 laminated on at least one surface thereof and containing the above-mentioned pressure-sensitive adhesive composition. The pressure-sensitive adhesive layer 20 is usually laminated directly on the surface of the optical film 10.
The optical film 1 with the pressure-sensitive adhesive layer may have a separate film on the side of the pressure-sensitive adhesive layer 20 opposite to the optical film 10 side.

Since the pressure-sensitive adhesive layer 20 of the optical film 1 with a pressure-sensitive adhesive layer is formed by the pressure-sensitive adhesive composition described above, the optical film 1 has excellent reworkability after being left in a humidified heat environment.

The optical film 10 can be various optical films (films having optical characteristics) that can be incorporated into a liquid crystal display device or an organic EL display device. The optical film 10 may be an optical film having a single-layer structure or an optical film having a multi-layer structure.

Specific examples of the single-layer structure optical film include optical functional films such as a splitter, a retardation film, a luminance improving film, an antiglare film, an antireflection film, a diffusion film, and a light-collecting film.

Examples of the optical film having a multilayer structure include a polarizing plate and a retardation plate. In the present specification, the polarizing plate means a polarizing plate 12 (FIGS. 2 and 3) in which protective films 13 and 14 (FIGS. 2 and 3) or a resin layer are laminated on at least one surface.
The retardation plate means a film in which a protective film or a resin layer is laminated on at least one surface of the retardation film.
When the optical film 1 with the pressure-sensitive adhesive layer includes a polarizing plate as the optical film 10, as shown in FIGS. 2 and 3, the polarizing plate has protective films 13 and 14 laminated on one side or both sides of the polarizing element 12. Can have a structure. In the optical film 1 with a pressure-sensitive adhesive layer, when the polarizing plate has the protective film 13 on only one side, the pressure-sensitive adhesive layer 20 is preferably provided on the polarizing element 12 side of the polarizing plate, as shown in FIG.

The optical film 10 is preferably a polarizing plate, a polarizing element, a retardation plate or a retardation film, and more preferably a polarizing plate or a polarizing plate.

The pressure-sensitive adhesive layer 20 can be used to bond the optical film 1 with the pressure-sensitive adhesive layer to, for example, an image display element or the like.

In the optical film 1 with an adhesive layer, the adhesive composition is directly applied to the surface of the optical film 10 to form the adhesive layer 20, and if necessary, a separate film is laminated on the outer surface of the adhesive layer 20 to adhere. The optical film 1 with an agent layer may be used.
Alternatively, a pressure-sensitive adhesive having a separate film is formed by directly applying the pressure-sensitive adhesive composition to the release-treated surface of the separate film to form the pressure-sensitive adhesive layer 20, and laminating the pressure-sensitive adhesive layer with the separate film on the optical film 10. The layered optical film 1 can be obtained.

[Polarizer]
The splitter 12 is a film having a property of absorbing linearly polarized light having a vibration plane parallel to the absorption axis and transmitting linear polarization having a vibration plane orthogonal to the absorption axis (parallel to the transmission axis).
The decoder 12 may be, for example, a film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, or a dichroic dye is oriented on a polymerizable liquid crystal compound to polymerize the polymerizable liquid crystal compound. It may be a cured film.

The polyvinyl alcohol-based resin can be obtained by saponifying the polyvinyl acetate-based resin. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer of a monomer copolymerizable with vinyl acetate and vinyl acetate. Examples of the monomer copolymerizable with vinyl acetate include unsaturated carboxylic acid, olefin, vinyl ether, unsaturated sulfonic acid, and (meth) acrylamide having an ammonium group.
As the dichroic dye, iodine or a dichroic organic dye is used.

The saponification degree of the polyvinyl alcohol-based resin is usually 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The average degree of polymerization of the polyvinyl alcohol-based resin is usually 1000 to 10000, preferably 1500 to 5000. The average degree of polymerization of the polyvinyl alcohol-based resin can be determined in accordance with JIS K 6726.

Usually, a film made of a polyvinyl alcohol-based resin is used as the raw film of the polarizing element 12. The polyvinyl alcohol-based resin can be formed into a film by a known method. The thickness of the raw film is usually 1 to 150 μm, and is preferably 10 μm or more in consideration of ease of stretching and the like.

The polarizing element 12, which is a film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, is, for example, a step of uniaxially stretching the original film, and the film is dyed with the dichroic dye to form the two colors. A step of adsorbing a sex dye, a step of treating the film with an aqueous boric acid solution, and a step of washing the film with water are performed, and finally the film is dried to produce the film. The thickness of the polarizing element 12 is usually 1 to 30 μm, and is preferably 20 μm or less, more preferably 15 μm or less, still more preferably 10 μm or less, from the viewpoint of thinning the optical film 1 with the pressure-sensitive adhesive layer.

The polarizing element 12, which is formed by adsorbing and orienting a bicolor dye on a polyvinyl alcohol-based resin film, 1) uses a single film of a polyvinyl alcohol-based resin film as a raw film, and uniaxially stretches and bicolors the film. In addition to the method of dyeing the dye, 2) a coating liquid (aqueous solution, etc.) containing a polyvinyl alcohol-based resin was applied to the base film and dried to obtain a base film having a polyvinyl alcohol-based resin layer. After that, this can also be obtained by uniaxially stretching the base film together with the base film, subjecting the stretched polyvinyl alcohol-based resin layer to a dyeing treatment of a bicolor dye, and then peeling off the base film. As the base film, a film made of a thermoplastic resin similar to the thermoplastic resin that can form the protective films 13 and 14 described later can be used, and a polyester resin such as polyethylene terephthalate, a polycarbonate resin, and the like can be used. It is a film made of a cellulose-based resin such as triacetyl cellulose, a cyclic polyolefin-based resin such as norbornene-based resin, and a polystyrene-based resin.

As a method for producing the polarizing element 12, which is a cured film obtained by orienting a dichroic dye on a polymerizable liquid crystal compound and polymerizing the polymerizable liquid crystal compound, the polymerizable liquid crystal compound and the dichroic dye are placed on a base film. Examples thereof include a method of applying the composition for forming a polarizing layer containing the mixture, polymerizing the polymerizable liquid crystal compound while maintaining the liquid crystal state, and curing the polymer to form the polarizing element 12. The polarizing element 12 thus obtained is in a state of being laminated on the base film, and the polarizing element with the base film may be used as a polarizing plate. As the base film, those described above can be used.

As the dichroic dye, a dye having a property that the absorbance in the major axis direction and the absorbance in the minor axis direction of the molecule are different can be used. For example, a dye having an absorption maximum wavelength (λmax) in the range of 300 to 700 nm. Is preferable. Examples of such a dichroic dye include an acridine dye, an oxazine dye, a cyanine dye, a naphthalene dye, an azo dye, an anthraquinone dye and the like, and among them, the azo dye is preferable. Examples of the azo dye include a monoazo dye, a bisazo dye, a trisazo dye, a tetrakisazo dye, a stilbene azo dye and the like, and a bisazo dye and a trisazo dye are more preferable.

The composition for forming a polarizing layer may contain a solvent, a polymerization initiator such as a photopolymerization initiator, a photosensitizer, a polymerization inhibitor and the like. As the polymerizable liquid crystal compound, the dichroic dye, the solvent, the polymerization initiator, the photosensitizer, the polymerization inhibitor and the like contained in the composition for forming the polarizing layer, known ones can be used, for example, specially. The ones exemplified in Japanese Patent Publication No. 2017-102479 and Japanese Patent Application Laid-Open No. 2017-83843 can be used. As a method for forming a linear polarizing layer using a composition for forming a polarizing layer, the method exemplified in the above-mentioned publication can also be adopted.

[Protective film]
The protective films 13 and 14 are independently translucent, preferably optically transparent thermoplastic resin, for example, a chain polyolefin resin (polyethylene resin, polypropylene resin, etc.), a cyclic polyolefin resin, etc. Polyethylene resin such as (norbornen resin etc.); Cellulosic resin (cellulose ester resin etc.); Polyethylene resin (polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate etc.); Polycarbonate resin; (meth) acrylic resin A film made of a resin; a polystyrene-based resin; a polyether ether ketone-based resin; a polysulfone-based resin, a mixture thereof, a copolymer, or the like can be used. Above all, the protective films 13 and 14 are preferably composed of a resin selected from the group consisting of a cyclic polyolefin resin, a polycarbonate resin, a cellulose resin, a polyester resin, and a (meth) acrylic resin, respectively. It is more preferable to be composed of a resin selected from the group consisting of a cellulose-based resin, a cyclic polyolefin-based resin, and a (meth) acrylic-based resin.

Examples of the chain polyolefin resin include homopolymers of chain olefins such as polyethylene resin and polypropylene resin, and copolymers composed of two or more kinds of chain olefins.

The cyclic polyolefin resin is a general term for resins containing norbornene, tetracyclododecene (also known as dimethanooctahydronaphthalene), or a cyclic olefin typified by a derivative thereof as a polymerization unit. Specific examples of the cyclic polyolefin resin include a ring-opened (co) polymer of a cyclic olefin and a hydrogenated product thereof, an addition polymer of a cyclic olefin, a cyclic olefin and a chain olefin such as ethylene and propylene, or a vinyl group. Examples thereof include copolymers with aromatic compounds, and modified (co) polymers obtained by modifying these with unsaturated carboxylic acids or derivatives thereof. Among them, a norbornene-based resin using a norbornene-based monomer such as a norbornene or a polycyclic norbornene-based monomer is preferably used as the cyclic olefin.

The cellulosic resin is preferably a cellulose ester resin, that is, a partially or completely esterified product of cellulose, and examples thereof include an acetate ester of cellulose, a propionic acid ester, a butyric acid ester, and a mixed ester thereof. Among them, triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate and the like are preferably used.

The polyester-based resin is a resin other than the above-mentioned cellulose ester-based resin having an ester bond, and is generally composed of a polyvalent carboxylic acid or a polycondensate of a derivative thereof and a polyhydric alcohol. Specific examples of the polyester-based resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethylterephthalate, and polycyclohexanedimethylnaphthalate.

The polycarbonate resin is a polyester formed from carbonic acid and glycol or bisphenol. Among them, aromatic polycarbonate having a diphenylalkane in the molecular chain is preferably used from the viewpoint of heat resistance, weather resistance and acid resistance. As the polycarbonate, 2,2-bis (4-hydroxyphenyl) propane (also known as bisphenol A), 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1 Examples thereof are polycarbonates derived from bisphenols such as -bis (4-hydroxyphenyl) isobutane, 1,1-bis (4-hydroxyphenyl) ethane.

The (meth) acrylic resin that can constitute the protective films 13 and 14 can be a polymer mainly composed of a structural unit derived from methacrylic acid ester (for example, containing 50% by mass or more thereof), and other polymers thereof. It is preferably a copolymer in which the copolymerization component is copolymerized. The (meth) acrylic resin may contain two or more kinds of structural units derived from methacrylic acid ester. Examples of the methacrylic acid ester include C ₁ to C ₄ alkyl esters of methacrylic acid such as methyl methacrylate, ethyl methacrylate and butyl methacrylate.

Examples of the copolymerization component that can be copolymerized with the methacrylic acid ester include acrylic acid esters. The acrylic acid ester is preferably a C ₁ to C ₈ alkyl ester of acrylic acid such as methyl acrylate, ethyl acrylate, butyl acrylate and 2-ethyl hexyl acrylate. Specific examples of other copolymerization components include unsaturated acids such as (meth) acrylic acid; aromatic vinyl compounds such as styrene, halogenated styrene, α-methylstyrene and vinyltoluene; and vinyl cyan compounds such as (meth) acrylonitrile. Unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride; unsaturated imides such as phenylmaleimide and cyclohexylmaleimide, other than acrylic acid esters having one polymerizable carbon-carbon double bond in the molecule. Compounds can be mentioned. A compound having two or more polymerizable carbon-carbon double bonds in the molecule may be used as a copolymerization component. As the copolymerization component, only one kind may be used, or two or more kinds may be used in combination.

The (meth) acrylic resin may have a ring structure in the polymer main chain in that the durability of the film can be enhanced. The ring structure is preferably a heterocyclic structure such as a cyclic acid anhydride structure, a cyclic imide structure, or a lactone ring structure. Specific examples of the cyclic acid anhydride structure include a glutaric anhydride structure and a succinic anhydride structure, specific examples of the cyclic imide structure include a glutarimide structure and a succinic anhydride structure, and specific examples of the lactone ring structure include a butyrolactone ring. The structure and the valerolactone ring structure are mentioned respectively.

The (meth) acrylic resin may contain acrylic rubber particles from the viewpoint of film forming property on the film, impact resistance of the film, and the like. Acrylic rubber particles are particles containing an elastic polymer mainly composed of an acrylic acid ester as an essential component, and have a single-layer structure substantially composed of only this elastic polymer or one layer of the elastic polymer. There is a multi-layered structure. Examples of the elastic polymer include a crosslinked elastic copolymer containing an alkyl acrylate as a main component and copolymerized with another copolymerizable vinyl monomer and a crosslinkable monomer. Examples of the alkyl acrylate which is the main component of the elastic polymer include C ₁ to C ₈ alkyl esters of acrylic acid such as methyl acrylate, ethyl acrylate, butyl acrylate and 2-ethyl hexyl acrylate. The number of carbon atoms of the alkyl group is preferably 4 or more.

Examples of other vinyl monomers copolymerizable with alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, and more specifically, methacrylic acid such as methyl methacrylate. Examples thereof include esters, aromatic vinyl compounds such as styrene, and vinyl cyan compounds such as (meth) acrylonitrile. Examples of the crosslinkable monomer include crosslinkable compounds having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, ethylene glycol di (meth) acrylate and butanediol di (). Examples thereof include (meth) acrylates of polyhydric alcohols such as meta) acrylates, alkenyl esters of (meth) acrylic acids such as allyl (meth) acrylates, and divinylbenzene.

The content of the acrylic rubber particles is preferably 5 parts by mass or more, and more preferably 10 parts by mass or more with respect to 100 parts by mass of the (meth) acrylic resin. If the content of the acrylic rubber particles is too large, the surface hardness of the film may be lowered, and the solvent resistance to the organic solvent in the surface treatment agent may be lowered when the film is surface-treated. Therefore, the content of the acrylic rubber particles is usually 80 parts by mass or less, preferably 60 parts by mass or less, with respect to 100 parts by mass of the (meth) acrylic resin.

The protective films 13 and 14 can contain conventional additives in the technical field of the present invention. Specific examples of the additive include, for example, an ultraviolet absorber, an infrared absorber, an organic dye, a pigment, an inorganic dye, an antioxidant, an antistatic agent, a surfactant, a lubricant, a dispersant, a heat stabilizer and the like. ..

Examples of the ultraviolet absorber include salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, triazine compounds, cyano (meth) acrylate compounds, nickel complex salts and the like.

The protective films 13 and 14 may be either an unstretched film or a uniaxially or biaxially stretched film, respectively. The biaxial stretching may be simultaneous biaxial stretching in which the two stretching directions are simultaneously stretched, or sequential biaxial stretching in which the stretching is performed in a predetermined direction and then in the other direction. The protective film 13 and / or the protective film 14 may be a protective film that plays a role of protecting the polarizing element 12, or may be a protective film that also has an optical function such as a retardation film described later. The retardation film is an optical film that exhibits optical anisotropy. For example, an arbitrary retardation value was given by stretching a film made of the thermoplastic resin (uniaxial stretching or biaxial stretching, etc.) or forming a liquid crystal layer or the like on the thermoplastic resin film. It can be a retardation film.

The protective films 13 and 14 may be films made of the same thermoplastic resin, or may be films made of different thermoplastic resins. The protective films 13 and 14 may be the same or different in terms of thickness, presence / absence of additives, their types, retardation characteristics, and the like.

The protective film 13 and / or the protective film 14 has a hard coat layer, an antiglare layer, an antireflection layer, a light diffusion layer, an antistatic layer, an antifouling layer, and a conductive film on the outer surface thereof (the surface opposite to the polarizing element 12). A surface treatment layer (coating layer) such as a layer may be provided.

The thicknesses of the protective films 13 and 14 are usually 1 to 150 μm, preferably 5 to 100 μm, and more preferably 5 to 60 μm, respectively. The thickness may be 50 μm or less, further 30 μm or less. Reducing the thickness of the protective films 13 and 14 is advantageous for thinning the optical film 1 with the pressure-sensitive adhesive layer and the display device including the optical film 1.

The protective films 13 and 14 can be attached to the polarizing element 12 via an adhesive layer or an adhesive layer. As the adhesive forming the adhesive layer, a water-based adhesive or an active energy ray-curable adhesive can be used.

Examples of the water-based adhesive include an adhesive made of a polyvinyl alcohol-based resin aqueous solution, a water-based two-component urethane-based emulsion adhesive, and the like. Of these, a water-based adhesive composed of an aqueous solution of polyvinyl alcohol-based resin is preferably used. Examples of the polyvinyl alcohol-based resin include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, and co-polymers of vinyl acetate and other monomers copolymerizable therewith. A polyvinyl alcohol-based copolymer obtained by saponifying the polymer, a modified polyvinyl alcohol-based polymer in which the hydroxyl groups thereof are partially modified, or the like can be used. The water-based adhesive may contain a cross-linking agent such as an aldehyde compound, an epoxy compound, a melamine compound, a methylol compound, an isocyanate compound, an amine compound, and a polyvalent metal salt.

When a water-based adhesive is used, it is preferable to carry out a step of adhering the polarizing element 12 and the protective films 13 and 14 and then drying them in order to remove water contained in the water-based adhesive. After the drying step, a curing step of curing at a temperature of, for example, about 20 to 45 ° C. may be provided.

The active energy ray-curable adhesive refers to an adhesive that cures by irradiating with active energy rays such as ultraviolet rays and electron beams, for example, a curable composition containing a polymerizable compound and a photopolymerization initiator, and light. Examples thereof include a curable composition containing a reactive resin, a curable composition containing a binder resin and a photoreactive cross-linking agent, and the like. A UV curable adhesive is preferred. Examples of the polymerizable compound include a photopolymerizable monomer such as a photocurable epoxy-based monomer, a photocurable (meth) acrylic-based monomer, and a photocurable urethane-based monomer, and an oligomer derived from the photopolymerizable monomer. .. Examples of the photopolymerization initiator include substances that generate active species such as neutral radicals, anionic radicals, and cationic radicals when irradiated with active energy rays. As an active energy ray-curable adhesive containing a polymerizable compound and a photopolymerization initiator, a curable composition containing a photocurable epoxy-based monomer and a photocationic polymerization initiator, a photocurable (meth) acrylic monomer and light. A curable composition containing a radical polymerization initiator or a mixture of these curable compositions can be preferably used.

When an active energy ray-curable adhesive is used, the substituent 12 and the protective films 13 and 14 are bonded together, and if necessary, a drying step is performed, and then the active energy ray is cured by irradiating the active energy ray. A curing step is performed to cure the sex adhesive. The light source of the active energy ray is not particularly limited, but ultraviolet rays having a emission distribution having a wavelength of 400 nm or less are preferable, and specifically, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a chemical lamp, a black light lamp, and a micro. A wave-excited mercury lamp, a metal halide lamp, or the like can be used.

When the polarizing element 12 and the protective films 13 and 14 are bonded to each other, at least one of these bonded surfaces can be subjected to surface activation treatment such as saponification treatment, corona treatment, and plasma treatment. When the protective films 13 and 14 are bonded to both sides of the polarizing element 12, the adhesive for bonding the protective films 13 and 14 may be the same type of adhesive or different types of adhesives. You may.

[Polarizer]
The polarizing plate may further include other films or layers other than the polarizing element 12 and the protective films 13 and 14. Examples of other films or layers include a luminance film, an antiglare film, an antireflection film, a diffusion film, a light-collecting film, an adhesive layer other than the adhesive layer 20, a coating layer, and a protective film, in addition to the retardation film described later. And so on. The protective film is a film used for the purpose of protecting the surface of the optical film 10 such as a polarizing plate from scratches and stains, and the optical film 1 with an adhesive layer is bonded onto an adherend such as an image display element. After that, it is usually peeled off.

The protective film is usually composed of a base film and an adhesive layer laminated on the base film. The base film is composed of a thermoplastic resin, for example, a polyolefin resin such as a polyethylene resin or a polypropylene resin; a polyester resin such as polyethylene terephthalate or polyethylene naphthalate; a polycarbonate resin; a (meth) acrylic resin or the like. be able to.

[Phase difference plate]
The retardation film contained in the retardation plate is an optical film exhibiting optical anisotropy, and in addition to the thermoplastic resin exemplified above as being usable for the protective films 13 and 14, for example, a polyvinyl alcohol-based resin. , Polyarylate resin, polyimide resin, polyether sulfone resin, polyvinylidene fluoride / polymethylmethacrylate resin, liquid crystal polyester resin, ethylene-vinyl acetate copolymer saken product, polyvinyl chloride resin, etc. It can be a stretched film obtained by stretching the resin film to be 1.01 to 6 times. Among them, a polycarbonate-based resin film, a cyclic olefin-based resin film, a (meth) acrylic-based resin film, or a cellulose-based resin film is uniaxially stretched or biaxially stretched, and a stretched film is preferable. Further, in the present specification, the zero retardation film is also included in the retardation film (however, it can also be used as a protective film). In addition, films called uniaxial retardation films, wide viewing angle retardation films, low photoelastic modulus retardation films and the like can also be applied as retardation films.

The zero retardation film refers to a film having both an in-plane retardation value _Re and a thickness direction retardation value R _th of -15 to 15 nm. This retardation film is suitably used for an IPS mode liquid crystal display device. The in-plane retardation value R _e and the thickness direction retardation value R _th are preferably −10 to 10 nm, and more preferably both −5 to 5 nm. The in-plane retardation value _Re and the thickness direction retardation value _Rth here are values at a wavelength of 590 nm.

The in-plane phase difference value _Re and the thickness direction phase difference value R _th are defined by the following equations, respectively.
R _e = (n _x − n _y ) × d
R _th = [(n _x + n _y ) / 2-n _z ] × d
[In the equation, n _x is the refraction coefficient in the slow axis direction (x-axis direction) in the film plane, and _ny is the phase advance axis direction in the film plane (y-axis direction orthogonal to the x-axis in the plane). Nz is the refractive index in the film thickness direction (the _z -axis direction perpendicular to the film surface), and d is the thickness of the film.

As the zero retardation film, for example, a resin film made of a polyolefin resin such as a cellulose resin, a chain polyolefin resin and a cyclic polyolefin resin, a polyethylene terephthalate resin or a (meth) acrylic resin can be used. In particular, since the retardation value can be easily controlled and easily obtained, a cellulosic resin, a polyolefin resin or a (meth) acrylic resin is preferably used.

Further, a film in which optical anisotropy is expressed by coating and orientation of a liquid crystal compound and a film in which optical anisotropy is developed by coating an inorganic layered compound can also be used as a retardation film. In such a retardation film, what is called a temperature-compensated retardation film, and a rod-shaped liquid crystal sold by JX Nikko Niseki Energy Co., Ltd. under the trade name of "NH film" are tilt-oriented. Film, a completely biaxial film sold by Fuji Film Co., Ltd. under the brand name of "WV Film", a film with tilt-oriented disc-shaped liquid crystal, and sold by Sumitomo Chemical Co., Ltd. under the brand name of "VAC Film". There are oriented type films, biaxially oriented films also sold by Sumitomo Chemical Co., Ltd. under the trade name of "new VAC film".

As the protective film laminated on at least one surface of the retardation film, for example, the above-mentioned protective films 13 and 14 can be used.

[Use of optical film with adhesive layer]
The above-mentioned optical film 1 with an adhesive layer can be used by incorporating it into a display device such as a liquid crystal display device or an organic EL display device. In this case, the optical film 1 with the pressure-sensitive adhesive layer may be attached to the image display element of the display device via the pressure-sensitive adhesive layer 20. Examples of the image display element include a liquid crystal panel and an organic EL element.

Since the optical film 1 with an adhesive layer is also excellent in reworkability after being left in a humidified heat environment, it is possible to suppress the occurrence of fogging or stains on the surface of the image display element due to the rework.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Hereinafter, the portion and% indicating the amount or content used are based on mass unless otherwise specified.

<Manufacturing Examples 1 to 5: Production of (meth) acrylic resin>
The monomer composition shown in Table 1 (number of parts [parts by mass] when the total amount of monomers is 100 parts by mass) was diluted with ethyl acetate in a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer, and a stirrer. A monomer mixture was charged. The internal temperature was raised to 55 ° C. while replacing the air in the reaction vessel with nitrogen gas to make it oxygen-free. Then, a total amount of a solution of azobisisobutyronitrile (polymerization initiator) in ethyl acetate was added. After adding the polymerization initiator, the mixture was kept at this temperature for 1 hour, and then ethyl acetate was continuously added into the reaction vessel while keeping the internal temperature at 54 to 56 ° C., and the concentration of the (meth) acrylic resin was 35% by mass. When the temperature reached%, the addition of ethyl acetate was stopped, and the temperature was kept at this temperature until 12 hours had passed from the start of addition of ethyl acetate. Finally, ethyl acetate was added to adjust the concentration of the (meth) acrylic resin to 20% by mass to prepare an ethyl acetate solution of the (meth) acrylic resin.

[Measurement of glass transition temperature (Tg) of (meth) acrylic resin]
The glass transition temperature (Tg) of the (meth) acrylic resin is measured in a nitrogen atmosphere using a differential scanning calorimeter (DSC) "EXSTAR DSC6000" manufactured by SI Nanotechnology Co., Ltd., in a measurement temperature range of -80 to 50. The measurement was carried out under the conditions of ° C. and a heating rate of 10 ° C./min. The results are shown in Table 1.

[Measurement of weight average molecular weight and number average molecular weight of (meth) acrylic resin]
The weight average molecular weight (Mw) and number average molecular weight (Mn) of the (meth) acrylic resin are four "TSKgel XL" manufactured by Toso Co., Ltd. and Showa Denko Co., Ltd. as columns for the GPC device. A total of 5 "Shodex GPC KF-802" sold by Showa Denko Corporation are connected in series and arranged, using tetrahydrofuran as the eluent, sample concentration 5 mg / mL, sample introduction amount 100 μL, temperature. It was measured by standard polystyrene conversion under the conditions of 40 ° C. and a flow rate of 1 mL / min. The results are shown in Table 1.

表１中の「モノマー組成」の欄にある略称は、次のモノマーを意味する。
ＢＡ ：ブチルアクリレート（アクリル酸ブチル）
ＭＡ ：メチルアクリレート（アクリル酸メチル）
ＰＥＡ ：アクリル酸２－フェノキシエチル
ＨＥＡ ：２－ヒドロキシエチルアクリレート（アクリル酸２－ヒドロキシエチル）
ＡＡ ：アクリル酸

The abbreviations in the "monomer composition" column in Table 1 mean the following monomers.
BA: Butyl acrylate (butyl acrylate)
MA: Methyl acrylate (methyl acrylate)
PEA: 2-phenoxyethyl acrylate HEA: 2-hydroxyethyl acrylate (2-hydroxyethyl acrylate)
AA: Acrylic acid

[Examples 1 to 11, Comparative Examples 1 to 3]
(1) Preparation of Adhesive Composition The amount of the cross-linking agent, the silane compound, and the ionic compound shown in Table 2 with respect to 100 parts of the solid content of the (meth) acrylic resin obtained in Production Example 1 [parts by mass]. , And ethyl acetate was added so that the solid content concentration became 14% by mass to prepare a solution of the pressure-sensitive adhesive composition. In Table 2, the blending amount [parts by mass] of the cross-linking agent, the silane compound, and the ionic compound is the amount in terms of solid content.

表２中の各配合成分は、次の化合物を意味する。
［架橋剤］
架橋剤（Ｂ）（芳香族系イソシアネート架橋剤（Ｂ１）に相当）：コロネートＬ（トリレンジイソシアネートのトリメチロールプロパンアダクト体の酢酸エチル溶液：固形分濃度７５質量％）、東ソー（株）製
［シラン化合物］
シラン化合物（Ｃ１－１）（メルカプト基含有シラン化合物（Ｃ１）に相当）：メルカプト基含有シリコーンオリゴマー「ＫＲ－５１９」（メルカプト当量４５０ｇ／ｍｏｌ）、信越化学工業（株）製
シラン化合物（Ｃ１－２）（メルカプト基含有シラン化合物（Ｃ１）に相当）：３－メルカプトプロピルトリメトキシシラン「ＫＢＭ－８０３」（分子量１９６．３４）、信越化学工業（株）製
シラン化合物（Ｃ２－１）（エポキシ基含有シラン化合物（Ｃ２）に相当）：３－グリシドキシプロピルトリメトキシシラン「ＫＢＭ－４０３」（分子量２３６．３４）、信越化学工業（株）製
シラン化合物（Ｃ２－２）（エポキシ基含有シラン化合物（Ｃ２）に相当）：８－グリシドキシオクチルトリメトキシシラン「ＫＢＭ－４８０３」（分子量３０６．４７）、信越化学工業（株）製
シラン化合物（Ｃ２－３）（エポキシ基含有シラン化合物（Ｃ２）に相当）：２－（３，４－エポキシシクロヘキシル）エチルトリメトキシシラン「ＫＢＭ－３０３」（分子量２４６．３８）、信越化学工業（株）製
シラン化合物（Ｃ２－４）（エポキシ基含有シラン化合物（Ｃ２）に相当）：エポキシ基含有シリコーンオリゴマー「ＫＲ－５１７」（エポキシ当量８３０ｇ／ｍｏｌ）、信越化学工業（株）製
［イオン性化合物］
イオン性化合物（Ｄ）：Ｎ－ヘキシル－４－メチルピリジニウム６フッ化リン（６０％トルエン溶液）

Each compounding ingredient in Table 2 means the following compounds.
[Crosslinking agent]
Crosslinking agent (B) (corresponding to aromatic isocyanate crosslinking agent (B1)): Coronate L (ethyl acetate solution of trimethylolpropane adduct compound of tolylene diisocyanate: solid content concentration 75% by mass), manufactured by Tosoh Corporation [ Silane compound]
Silane compound (C1-1) (corresponding to mercapto group-containing silane compound (C1)): mercapto group-containing silicone oligomer "KR-519" (mercapto equivalent 450 g / mol), silane compound (C1-) manufactured by Shin-Etsu Chemical Industry Co., Ltd. 2) (Equivalent to mercapto group-containing silane compound (C1)): 3-mercaptopropyltrimethoxysilane "KBM-803" (molecular weight 196.34), silane compound (C2-1) manufactured by Shin-Etsu Chemical Industry Co., Ltd. (epoxide) Group-containing silane compound (C2)): 3-glycidoxypropyltrimethoxysilane "KBM-403" (molecular weight 236.34), silane compound (C2-2) manufactured by Shin-Etsu Chemical Industry Co., Ltd. (containing epoxy group) (Equivalent to silane compound (C2)): 8-glycidoxyoctyltrimethoxysilane "KBM-4803" (molecular weight 306.47), silane compound (C2-3) manufactured by Shin-Etsu Chemical Industry Co., Ltd. (epoxide group-containing silane compound) (Equivalent to (C2)): 2- (3,4-epoxide cyclohexyl) ethyltrimethoxysilane "KBM-303" (molecular weight 246.38), silane compound (C2-4) (epoxide group) manufactured by Shin-Etsu Chemical Industry Co., Ltd. Epoxide group-containing silicone oligomer "KR-517" (epoxide equivalent 830 g / mol), manufactured by Shin-Etsu Chemical Industry Co., Ltd. [ionic compound]
Ionic compound (D): N-hexyl-4-methylpyridinium hexafluorinated phosphorus (60% toluene solution)

(2) Preparation of Adhesive Layer The adhesive composition prepared in (1) above is a separate film made of a polyethylene terephthalate film that has undergone a mold release treatment [“PLR-382190” obtained from Lintec Co., Ltd.]. The release-treated surface was coated with an applicator so that the thickness after drying was 20 μm, and dried at 100 ° C. for 1 minute to prepare an adhesive layer (adhesive sheet).

[Measurement of gel fraction]
The gel fraction [gel fraction (G23) at a temperature of 23 ° C.] was measured for the pressure-sensitive adhesive layer (adhesive sheet) left at 23 ° C. for 5 days immediately after being obtained. The gel fraction was measured according to the following [a] to [d]. The results are shown in Table 3.
[A] An adhesive layer having an area of about 8 cm × about 8 cm and a metal mesh (the mass thereof is Wm) made of SUS304 having an area of about 10 cm × about 10 cm are bonded together.
[B] The bonded product obtained in the above [a] is weighed to a mass of Ws, then folded four times so as to wrap the adhesive layer, stapled, and then weighed. Let the mass be Wb.
[C] The mesh stapled in [b] above is placed in a glass container, 60 mL of ethyl acetate is added and immersed, and then the glass container is stored at room temperature for 3 days.
[D] The mesh is taken out from the glass container, dried at 120 ° C. for 4 hours, then weighed, and the mass is defined as Wa.
The gel fraction is calculated based on gel fraction (% by mass) = [{Wa- (Wb-Ws) -Wm} / (Ws-Wm)] x 100.

(3) Preparation of polarizing plate A protective film having a thickness of 75 μm made of a (meth) acrylic resin is attached to one side of a polarizing element having a thickness of 23 μm in which iodine is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol film, and a cyclic polyolefin resin is formed on the other surface. A polarizing plate was produced by laminating a protective film as a retardation film having a thickness of 50 μm, which comprises, via an active energy ray-curable adhesive.

(4) Preparation of a polarizing plate with an adhesive layer On the outer surface of the polarizing plate on the protective film side made of a cyclic polyolefin resin, the surface of the pressure-sensitive adhesive layer prepared in (2) above is opposite to the separate film (adhesive). The layer surface) was bonded by a laminator and then cured under the conditions of a temperature of 23 ° C. and a relative humidity of 65% RH for 5 days to obtain a polarizing plate with an adhesive layer.

(5) Evaluation [Evaluation of peelability of separate film]
The polarizing plate with the pressure-sensitive adhesive layer obtained in (4) above was cut into a size of 120 mm × 25 mm so that the absorption axis of the polarizing element had a long side. A 120 mm x 25 mm double-sided tape (Nystack (trade name), manufactured by Nichiban Co., Ltd.) is attached to a non-alkali glass substrate ["Eagle XG" manufactured by Corning Co., Ltd.], and then this double-sided tape and the above (4) The test piece (platelet with a pressure-sensitive adhesive layer to which a glass substrate was attached) having a separate film on the outermost surface was prepared by laminating with the polarizing plate side of the polarizing plate with a pressure-sensitive adhesive layer obtained in 1. In this state, using an autograph (AGS-50NX, manufactured by Shimadzu Corporation), grasp one end (one side of 5 cm in width) of the separate film in the length direction, and the peeling speed under the conditions of temperature 23 ° C. and humidity 55% RH. It was pulled from the pressure-sensitive adhesive layer by pulling it in the 180 ° direction at 300 mm / min, and the peeling force at that time was recorded. Since the data is not stable immediately after the start of measurement and immediately before the end of measurement, 20% of the data after the start of measurement and 20% of the data after the end of measurement are cut, and the average value is calculated only from the range of 60% in the middle part, which is relatively stable. It was calculated and used as the peeling force [N / 25 mm] of the separate film.

[Evaluation of adhesion]
(Preparation of sample)
The polarizing plate with the pressure-sensitive adhesive layer obtained in (4) above was cut into a size of 150 mm × 25 mm so that the absorption axis of the polarizing element had a long side. The separate film is peeled off from the cut polarizing plate with the adhesive layer, and the exposed adhesive layer is removed from the central portion of a non-alkali glass substrate [“Eagle XG” manufactured by Corning Inc.] having a length of 160 mm, a width of 50 mm, and a thickness of 0.7 mm. The test piece (polarizing plate with an adhesive layer to which the glass substrate was attached) to which the obtained glass substrate was attached was placed in an autoclave at a temperature of 50 ° C. and a pressure of 5 kgf / cm ² (490.3 kPa). ), Pressurized for 20 minutes, and this was used as a sample.

(Measurement of adhesion at a temperature of 23 ° C)
The sample was stored for 24 hours in an environment with a temperature of 23 ° C. and a relative humidity of 55% RH. After that, a cutter blade is inserted between the glass substrate and the adhesive layer, peeled 30 mm from the end in the length direction, and the peeled part is peeled off by a universal tensile tester [trade name "AGS-50NX" manufactured by Shimadzu Corporation. "] I grabbed it with the grip. The test piece in this state is subjected to JIS K 6854-2: 1999 "Adhesive-Peeling Adhesive Strength Test Method-Part 2: 180 Degree Peeling" in an atmosphere with a temperature of 23 ° C and a relative humidity of 55% RH. Then, a 180-degree peeling test was performed at a gripping movement speed of 300 mm / min, and an average peeling force over a length of 120 mm excluding 30 mm of the gripped portion was obtained, which was used as the adhesion force at a temperature of 23 ° C. The results are shown in Table 3.

(Measurement of adhesion after leaving in a humidified heat environment and observation of the glass substrate surface)
The sample was stored for 240 hours in a humidified heat atmosphere with a temperature of 60 ° C. and a relative humidity of 90% RH. After that, a cutter blade is inserted between the glass substrate and the adhesive layer, peeled 30 mm from the end in the length direction, and the peeled part is peeled off by a universal tensile tester [trade name "AGS-50NX" manufactured by Shimadzu Corporation. "] I grabbed it with the grip. The test piece in this state is subjected to JIS K 6854-2: 1999 "Adhesive-Peeling Adhesive Strength Test Method-Part 2: 180 Degree Peeling" in an atmosphere with a temperature of 23 ° C and a relative humidity of 55% RH. Then, a 180-degree peeling test was performed at a gripping movement speed of 300 mm / min, and an average peeling force over a length of 120 mm excluding 30 mm of the gripped portion was obtained, which was used as the adhesion force after being left in a humidified heat environment. The results are shown in Table 3.

From the viewpoint of reworkability, it is preferable that the adhesion after being left in a humidified heat environment is 20 N / 25 mm or less. Further, it is preferable that the difference between the measured values of the adhesion after being left in the humidified heat environment and the adhesion at 23 ° C. is 18 N / 25 mm or less.

The surface of the glass substrate after the 180-degree peeling test after being left in a humidified heat environment was visually observed, and the appearance of the glass was evaluated according to the following criteria. From the viewpoint of reworkability, it is preferable that the evaluation results are A to C below. The results are shown in Table 3.
A: Almost no cloudiness or adhesive residue is observed on the surface of the glass substrate.
B: Almost no adhesive residue is observed on the surface of the glass substrate, but cloudiness is observed.
C: Adhesive residue is partially observed on the surface of the glass substrate.
D: Adhesive residue is observed on the entire surface of the glass substrate.

[Evaluation of antistatic property]
After peeling off the separate film from the polarizing plate with the pressure-sensitive adhesive layer prepared in (4) above, the surface resistance value of the pressure-sensitive adhesive layer is measured by the surface specific resistance measuring device ["High Restor-up MCP-HT450" manufactured by Mitsubishi Chemical Corporation. (Product name)]. The measurement conditions were an applied voltage of 100 V and an applied time of 30 seconds.

[Evaluation of durability]
After peeling off the separate film from the polarizing plate with an adhesive layer prepared in (4) above, the adhesive layer surface is attached to both sides of a non-alkali glass substrate [“Eagle XG” manufactured by Corning Inc.] so as to form a cross Nicol. It was worn to prepare a sample for evaluation. A heat resistance test and a heat shock test were performed using this evaluation sample.

(Heat resistance test)
A heat resistance test was performed in which the evaluation sample was held at a temperature of 80 ° C. under dry conditions for 500 hours.

(Heat shock (HS) test)
A heat shock (HS) test in which the evaluation sample is held for 30 minutes under a dry condition at a temperature of 70 ° C. and then held for 30 minutes under a dry condition at a temperature of -40 ° C. is one cycle, and this is repeated for 200 cycles. went.

For the evaluation samples after each of the heat resistance test and the HS test, visually observe the presence or absence of floating and peeling at the interface between the pressure-sensitive adhesive layer and the glass substrate, and the presence or absence of foaming of the pressure-sensitive adhesive layer, and follow the following evaluation criteria. The durability was evaluated. The results are shown in Table 3.
A: Some changes in appearance such as floating, peeling, and foaming are observed.
B: Significant changes in appearance such as floating, peeling, and foaming are observed.
C: Changes in appearance such as floating, peeling, and foaming are very large.

1 Optical film with adhesive layer, 10 Optical film, 12 Polarizer, 13 Protective film, 14 Protective film, 20 Adhesive layer.

Claims (11)

A pressure-sensitive adhesive composition containing a (meth) acrylic resin (A), a cross-linking agent (B), and a silane compound (C).
The silane compound (C) contains a mercapto group-containing silane compound (C1) and an epoxy group-containing silane compound (C2).
The pressure-sensitive adhesive composition having a content of the mercapto group-containing silane compound (C1) higher than that of the epoxy group-containing silane compound (C2). The (meth) acrylic resin (A) has a weight average molecular weight of 1 million or more, a glass transition temperature of −45 ° C. or higher, and contains a structural unit derived from (meth) acrylate having a hydroxyl group. The pressure-sensitive adhesive composition according to claim 1. The (meth) acrylic resin (A) further has a structural unit derived from the alkyl acrylate (a1) in which the glass transition temperature of the homopolymer is less than 0 ° C., and the glass transition temperature of the homopolymer is 0 ° C. or higher. The pressure-sensitive adhesive composition according to claim 1 or 2, which contains a structural unit derived from the alkyl acrylate (a2). The (meth) acrylic resin (A) further contains a structural unit derived from an unsaturated monomer having one olefinic double bond and at least one aromatic ring in the molecule. Item 3. The pressure-sensitive adhesive composition according to any one of Items 1 to 3. The pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the (meth) acrylic resin (A) further contains a structural unit derived from a carboxy group-containing (meth) acrylate. The cross-linking agent (B) contains an aromatic isocyanate cross-linking agent (B1).
Claim 1 that the content of the aromatic isocyanate cross-linking agent (B1) is 0.1 part by mass or more and 4.5 parts by mass or less with respect to 100 parts by mass of the (meth) acrylic resin (A). The pressure-sensitive adhesive composition according to any one of 5 to 5. The content of the mercapto group-containing silane compound (C1) is 0.1 parts by mass or more and 8 parts by mass or less with respect to 100 parts by weight of the (meth) acrylic resin (A), according to claims 1 to 6. The pressure-sensitive adhesive composition according to any one of the following items. The pressure-sensitive adhesive composition according to any one of claims 1 to 7, further comprising an ionic compound (D). A pressure-sensitive adhesive layer containing the pressure-sensitive adhesive composition according to any one of claims 1 to 8. An optical film with an pressure-sensitive adhesive layer, comprising the optical film and the pressure-sensitive adhesive layer according to claim 9, which is laminated on at least one surface thereof. The optical film with an adhesive layer according to claim 10, wherein the optical film includes a polarizing element and a protective film laminated on at least one surface thereof.

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