WO2020250749A1 - Pressure-sensitive adhesive composition, pressure-sensitive adhesive layer, pressure-sensitive adhesive sheet, and optical laminate - Google Patents

Abstract

Provided are: a pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer that enables release films provided on both surfaces thereof to be satisfactorily removed; the pressure-sensitive adhesive layer; a pressure-sensitive adhesive sheet; and an optical laminate. This pressure-sensitive adhesive composition contains a resin, a crosslinking agent, and a silane compound. The silane compound includes a Si-O-Si bond in the main chain. Both ends of the main chain of the silane compound each include a functional group other than a hydrolyzable group. A side chain of the silane compound includes a functional group other than a carboxyl group. The silane compound is preferably a leveling agent.

Description

Adhesive composition, adhesive layer, adhesive sheet, and optical laminate

The present invention relates to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive layer and a pressure-sensitive adhesive sheet using the pressure-sensitive adhesive composition, and an optical laminate including the pressure-sensitive adhesive layer.

Image display devices such as liquid crystal display devices and organic EL display devices generally have a configuration in which an optical member such as a polarizing plate or a retardation film is attached to a display unit including a display element or the like via an adhesive layer. There is. In such an image display device, for example, from an adhesive sheet having release films provided on both sides of the adhesive layer so as to be removable, one of the release films is peeled off and an exposed adhesive layer is attached to an optical member. It can be manufactured by peeling the other release film and then adhering the exposed pressure-sensitive adhesive layer to the display unit.

Japanese Unexamined Patent Publication No. 2016-194071

When the release films provided on both sides of the pressure-sensitive adhesive layer of the pressure-sensitive adhesive sheet have the same release-treated layer, the release force between the pressure-sensitive adhesive layer and the release-treated layer side of the release film is the same. Therefore, a part of the pressure-sensitive adhesive layer is peeled off together with one release film, the other part of the pressure-sensitive adhesive layer is peeled off together with the other release film, and the pressure-sensitive adhesive layer is partially separated. I have something to do. Such a defect is sometimes called crying farewell, but when crying farewell occurs, it becomes difficult to form a uniform adhesive layer between the optical member and the display unit, and the optical member and the display unit are good. It becomes difficult to secure good adhesiveness.

An object of the present invention is to provide an adhesive composition, an adhesive layer, an adhesive sheet, and an optical laminate for forming an adhesive layer capable of satisfactorily peeling a release film provided on both sides. To do.

The present invention provides the following pressure-sensitive adhesive compositions, pressure-sensitive adhesive layers, pressure-sensitive adhesive sheets, and optical laminates.
[1] Contains a resin, a cross-linking agent, and a silane compound.
The silane compound contains a Si—O—Si bond in the main chain.
Both ends of the main chain of the silane compound have functional groups other than hydrolyzable groups.
The side chain of the silane compound is a pressure-sensitive adhesive composition having a functional group other than a carboxyl group.
[2] The pressure-sensitive adhesive composition according to [1], wherein the silane compound is a leveling agent.
[3] The pressure-sensitive adhesive composition according to [1] or [2], wherein both ends of the main chain of the silane compound are independently an alkyl group, an alkyl halide group, a phenyl group, or an aralkyl group.
[4] The pressure-sensitive adhesive composition according to any one of [1] to [3], wherein both ends of the main chain of the silane compound are methyl groups.
[5] The pressure-sensitive adhesive composition according to any one of [1] to [4], wherein the side chains of the silane compound are independently alkyl groups or aralkyl groups.
[6] The pressure-sensitive adhesive composition according to any one of [1] to [5], wherein the silane compound has a viscosity of 300 mPa · s or more at a temperature of 25 ° C.
[7] The pressure-sensitive adhesive composition according to any one of [1] to [6], further comprising a silane coupling agent.
[8] The silane coupling agent contains a siloxane compound containing a Si—O—Si bond in the main chain, and contains the siloxane compound.
The pressure-sensitive adhesive composition according to [7], wherein the siloxane compound has a hydrolyzable group in the main chain.
[9] The pressure-sensitive adhesive composition according to any one of [1] to [8], wherein the resin contains a (meth) acrylic resin.
[10] A pressure-sensitive adhesive layer using the pressure-sensitive adhesive composition according to any one of [1] to [9].
[11] A pressure-sensitive adhesive sheet provided with a release film having the same release treatment layer on both sides of the pressure-sensitive adhesive layer according to [10].
The peeling force between one surface of the pressure-sensitive adhesive layer and the release-treated layer side of the release film is defined as the first peeling force, and the other surface of the pressure-sensitive adhesive layer opposite to the one surface. An adhesive sheet in which the first peeling force and the second peeling force are different from each other when the peeling force between the release film and the release treatment layer side of the release film is taken as the second peeling force.
[12] An optical laminate including an optical layer and an adhesive layer.
The pressure-sensitive adhesive layer is an optical laminate, which is the pressure-sensitive adhesive layer according to [10].
[13] The optical laminate according to [12], wherein the optical layer includes a polarizing plate.

According to the present invention, it is possible to provide an adhesive composition, an adhesive layer, an adhesive sheet, and an optical laminate for forming an adhesive layer capable of satisfactorily peeling the release films provided on both sides. it can.

It is the schematic sectional drawing which shows an example of the optical laminated body which concerns on this invention. It is schematic cross-sectional view which shows an example of the optical layer which the optical laminated body which concerns on this invention has. It is schematic cross-sectional view which shows another example of the optical layer which the optical laminated body which concerns on this invention has. It is schematic cross-sectional view which shows another example of the layer structure of the optical laminate which concerns on this invention. It is schematic cross-sectional view which shows another example of the layer structure of the optical laminate which concerns on this invention. It is schematic cross-sectional view which shows another example of the layer structure of the optical laminate which concerns on this invention. It is schematic cross-sectional view which shows another example of the layer structure of the optical laminate which concerns on this invention. It is schematic cross-sectional view which shows another example of the layer structure of the optical laminate which concerns on this invention.

<Adhesive composition>
The pressure-sensitive adhesive composition according to the present invention contains a resin, a cross-linking agent, and a silane compound. The pressure-sensitive adhesive composition may contain a silane coupling agent in addition to the resin, the cross-linking agent, and the silane compound. Hereinafter, the above resin is referred to as "resin (A)", the above cross-linking agent is referred to as "cross-linking agent (B)", the above-mentioned silane compound is referred to as "silane compound (C)", and the above-mentioned silane coupling agent is referred to as "silane coupling agent". (D) ".

Examples of the pressure-sensitive adhesive composition include (meth) acrylic pressure-sensitive adhesive compositions, urethane-based pressure-sensitive adhesive compositions, silicone-based pressure-sensitive adhesive compositions, polyester-based pressure-sensitive adhesive compositions, polyamide-based pressure-sensitive adhesive compositions, and polyether-based pressure-sensitive adhesive compositions. Examples thereof include a pressure-sensitive adhesive composition, a fluorine-based pressure-sensitive adhesive composition, and a rubber-based pressure-sensitive adhesive composition. Among the above-mentioned pressure-sensitive adhesive compositions, (meth) acrylic pressure-sensitive adhesive compositions are preferably used from the viewpoints of transparency, adhesive strength, reliability, reworkability and the like. As used herein, the term "(meth) acrylic" refers to at least one selected from the group consisting of acrylic and methacrylic. The same applies to the notations such as "(meth) acryloyl" and "(meth) acrylate".

(Resin (A))
The pressure-sensitive adhesive composition contains the resin (A). Examples of the resin (A) include (meth) acrylic resin, urethane resin, silicone resin, polyester resin, polyamide resin, polyether resin, fluorine resin, natural rubber, synthetic rubber and the like. .. Of these, from the viewpoint of transparency, adhesive strength, reliability, reworkability, etc., the resin (A) preferably contains (meth) acrylic resin as a main component (containing 50% by mass or more).

((Meta) acrylic resin)
Specific examples of the (meth) acrylic resin that can be suitably used as the resin (A) of the pressure-sensitive adhesive composition include the following formula (I):

A polymer containing a structural unit derived from a (meth) acrylic acid ester represented by (containing 50% by mass or more) as a main component (hereinafter, this polymer is referred to as "(meth) acrylic resin (a1)". There is.).

In the above formula (I), R ¹ represents a hydrogen atom or a methyl group, and R ² is an alkyl group having 1 to 14 carbon atoms or 1 to 14 carbon atoms which may be substituted with an alkoxy group having 1 to 10 carbon atoms. Represents an aralkyl group having 7 to 21 carbon atoms which may be substituted with 10 alkoxy groups. R ² is preferably an alkyl group which have carbon atoms 1 be ~ 14 substituted with an alkoxy group having 1 to 10 carbon atoms.

Specific examples of the (meth) acrylic acid ester represented by the formula (I) include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, (. Linear (meth) acrylic acid alkyl esters such as n-octyl (meth) acrylic acid, lauryl (meth) acrylic acid; isobutyl (meth) acrylic acid, 2-ethylhexyl (meth) acrylic acid, (meth) acrylic acid Includes branched (meth) acrylic acid alkyl esters such as isooctyl. The number of carbon atoms of the alkyl moiety in the (meth) acrylic acid alkyl ester is preferably 1 to 8, and more preferably 1 to 6.

When R ² is an alkyl group substituted with an alkoxy group, i.e., specific examples of the (meth) acrylic acid ester represented by formula (I) when R ² is an alkoxyalkyl group, (meth) acrylic Contains 2-methoxyethyl acid, ethoxymethyl (meth) acrylate and the like. Specific examples of the (meth) acrylic acid ester represented by the formula (I) when R ² is an aralkyl group having 7 to 21 carbon atoms include benzyl (meth) acrylate and the like.

As the (meth) acrylic acid ester represented by the formula (I), only one type may be used alone, or two or more types may be used in combination. Among them, the (meth) acrylic acid ester preferably contains a (meth) acrylic acid alkyl ester, and more preferably contains n-butyl (meth) acrylic acid. The (meth) acrylic resin (a1) preferably contains n-butyl acrylate in an amount of 50% by mass or more in all the monomers constituting the resin (a1). Of course, in addition to n-butyl acrylate, other (meth) acrylic acid ester represented by the formula (I) can also be used in combination.

The (meth) acrylic resin (a1) is usually a copolymer of the (meth) acrylic acid ester of the above formula (I) and at least one other monomer represented by a monomer having a polar functional group. It is a coalescence. The monomer having a polar functional group is preferably a (meth) acrylic acid-based compound having a polar functional group. Examples of the polar functional group include a heterocyclic group such as a free carboxyl group, a hydroxyl group, an amino group and an epoxy group.

Specific examples of the monomer having a polar functional group include a monomer having a free carboxyl group such as (meth) acrylic acid and β-carboxyethyl (meth) acrylate; 2-hydroxyethyl (meth) acrylic acid, ( 3-Hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2- (2-hydroxyethoxy) ethyl (meth) acrylate, 2- or 3-chloro-2-hydroxypropyl (meth) acrylate , Monomer with hydroxyl group such as diethylene glycol mono (meth) acrylate; (meth) acryloylmorpholin, vinylcaprolactam, N-vinyl-2-pyrrolidone, vinylpyridine, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl Monomers with heterocyclic groups such as (meth) acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, 2,5-dihydrofuran; aminoethyl (meth) acrylate, N, It contains a monomer having an amino group different from that of the heterocycle, such as N-dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylate. As the monomer having a polar functional group, only one kind may be used alone, or two or more kinds may be used in combination.

Among the above, from the viewpoint of the reactivity of the (meth) acrylic resin (a1), a monomer having a hydroxyl group as one of the polar functional group-containing monomers constituting the (meth) acrylic resin (a1). Is preferably used. In addition to the monomer having a hydroxyl group, it is also effective to use a monomer having another polar functional group, for example, a monomer having a free carboxyl group in combination.

The (meth) acrylic resin (a1) is a monomer having one olefinic double bond and at least one aromatic ring in the molecule (however, the monomer represented by the above formula (I)). And those corresponding to the above-mentioned monomers having a polar functional group)) may be further contained. A preferable example is a (meth) acrylic acid-based compound having an aromatic ring. A suitable example of a (meth) acrylic acid-based compound having an aromatic ring is the following formula (II) :.

It is a (meth) acrylic acid ester having an aryloxyalkyl group such as a (meth) acrylic acid ester containing a phenoxyethyl group represented by.

In the above formula (II), R ³ represents a hydrogen atom or a methyl group, n represents an integer of 1 to 8, and R ⁴ 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 to 9, when it is an aralkyl group, its carbon number is about 7 to 11, and when it is an aryl group, its carbon number is 6. It can be about 10.

Examples of the alkyl group having 1 to 9 carbon atoms constituting the R ⁴ in Formula (II), methyl, butyl, nonyl and the like. Examples of the aralkyl group having 7 to 11 carbon atoms, benzyl, phenethyl, naphthylmethyl and the like, Examples of the aryl group having 6 to 10 carbon atoms include phenyl, tolyl, naphthyl and the like.

Specific examples of the phenoxyethyl group-containing (meth) acrylic acid ester represented by the formula (II) include 2-phenoxyethyl (meth) acrylate, 2- (2-phenoxyethoxy) ethyl (2-phenoxyethoxy) ethyl (meth) acrylate, and ethylene oxide. It contains (meth) acrylic acid ester of 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 phenoxyethyl group-containing (meth) acrylic acid ester includes (meth) acrylate 2-phenoxyethyl, (meth) acrylate 2- (o-phenylphenoxy) ethyl and / or (meth) acrylate 2- (2). -Preferably containing phenoxyethoxy) ethyl.

The (meth) acrylic resin (a1) has a structural unit derived from the (meth) acrylic acid ester represented by the above formula (I), preferably 60 to 99.9 mass, based on the total solid content thereof. %, More preferably 80 to 99.6% by mass, and a structural unit derived from a monomer having a polar functional group, preferably 0.1 to 20% by mass, more preferably 0.4 to The structural unit derived from the monomer contained in a proportion of 10% by mass and having one olefinic double bond and at least one aromatic ring in the molecule is preferably 0 to 40% by mass, more preferably. Can be contained in a proportion of 6 to 12% by mass.

The (meth) acrylic resin (a1) contains at least one (meth) acrylic acid ester represented by the formula (I), a monomer having a polar functional group, and one olefinic double bond in the molecule. It may contain a structural unit derived from a monomer other than the monomer having an aromatic ring (hereinafter, also referred to as “other monomer”). Specific examples of other monomers are derived from a (meth) acrylic acid ester having an alicyclic structure in the molecule, a structural unit derived from a styrene-based monomer, and a vinyl-based monomer. It includes a structural unit, a structural unit derived from a monomer having a plurality of (meth) acryloyl groups in the molecule, a structural unit derived from a (meth) acrylamide monomer, and the like. As for other monomers, only one kind may be used alone, or two or more kinds may be used in combination.

The alicyclic structure usually has 5 or more carbon atoms, preferably about 5 to 7 carbon atoms. Specific examples of the (meth) acrylic acid ester having an alicyclic structure include isobornyl (meth) acrylate, cyclohexyl (meth) acrylate, dicyclopentanyl (meth) acrylate, cyclododecyl (meth) acrylate, (meth). Includes methylcyclohexyl acrylate, trimethylcyclohexyl (meth) acrylate, tert-butylcyclohexyl (meth) acrylate, cyclohexylphenyl (meth) acrylate, cyclohexyl α-ethoxy (meth) acrylate and the like.

Specific examples of styrene-based monomers are styrene; alkyl styrenes such as methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, and octyl styrene; Halogenized styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, iodostyrene; including nitrostyrene, acetylstyrene, methoxystyrene, divinylbenzene and the like.

Specific examples of vinyl-based monomers include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, vinyl halides such as vinyl laurate; vinyl halides such as vinyl chloride and vinyl bromide; Vinylidene chlorides such as vinylidene chloride; nitrogen-containing aromatic vinyls such as vinylpyridine, vinylpyrrolidone, vinylcarbazole; conjugated diene monomers such as butadiene, isoprene, chloroprene; acrylonitrile, methacrylonitrile and the like.

Specific examples of monomers 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. Two (meth) in the molecule such as di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate. Monomer having an acryloyl group; a monomer having three (meth) acryloyl groups in the molecule such as trimethyl propantri (meth) acrylate and the like are included.

Specific examples of (meth) acrylamide compounds 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.

The (meth) acrylic resin (a1) contains other monomers in a proportion of usually 0 to 20% by mass, preferably 0 to 10% by mass, based on the total amount of the solid content.

From the viewpoint of adhesion between the pressure-sensitive adhesive layer and the optical member, the (meth) acrylic resin (a1) has a standard polystyrene-equivalent weight average molecular weight (Mw) of 500,000 or more by gel permeation chromatography (GPC). It is preferably 600,000 or more, and more preferably 600,000 or more. The Mw of the (meth) acrylic resin (a1) is usually 1.7 million or less.

The resin (A) of the (meth) acrylic pressure-sensitive adhesive composition may contain two or more types of (meth) acrylic resin (a1). Further, the resin (A) is a structural unit derived from a (meth) acrylic resin different from the (meth) acrylic resin (a1), for example, a (meth) acrylic acid ester of the formula (I). The main component is a (meth) acrylic resin (a2) having no polar functional group and a structural unit derived from the (meth) acrylic acid ester represented by the above formula (I), and Mw is 0. A (meth) acrylic resin (a3) or the like in the range of 50,000 to 120,000 can be included.

(Crosslinking agent (B))
The pressure-sensitive adhesive composition contains a cross-linking agent (B). When the pressure-sensitive adhesive composition contains the cross-linking agent (B), a cross-linked structure is formed on the resin (A) contained in the pressure-sensitive adhesive composition, and the pressure-sensitive adhesive layer formed by using the pressure-sensitive adhesive composition has good durability. It is possible to impart sex and reworkability.

The cross-linking agent (B) is a compound that reacts with a structural unit particularly derived from a polar functional group-containing monomer in the resin (A) to cross-link the resin (A) such as the (meth) acrylic resin (a1). Is. Specific examples thereof include isocyanate compounds, epoxy compounds, aziridine compounds, and metal chelate compounds. Of these, the isocyanate-based compound, the epoxy-based compound, and the aziridine-based compound have at least two functional groups in the molecule that can react with the polar functional groups in the resin (A). 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 compound is a compound having at least two isocyanato groups (-NCO) in the molecule. Specific examples of the isocyanate-based compound include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate and the like. Further, an adduct compound obtained by reacting these isocyanate compounds with a polyol such as glycerol or trimethylolpropane, or a dimer or trimer of the isocyanate compound can also be used as the cross-linking agent (B).

An epoxy compound is a compound having at least two epoxy groups in the molecule. Specific examples of epoxy compounds 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 trimethylolpropane. Includes triglycidyl ether, N, N-diglycidyl aniline, N, N, N', N'-tetraglycidyl-m-xylene diamine, 1,3-bis (N, N'-diglycidyl aminomethyl) cyclohexane and the like. ..

The aziridine-based compound is a compound having at least two 3-membered ring skeletons consisting of one nitrogen atom and two carbon atoms, also called ethyleneimine, in the molecule. Specific examples of aziridine compounds 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), trimethylpropan-tris-β-aziridinyl propionate, tetramethylolmethane-tris -Includes β-aziridinyl propionate and the like.

Specific examples of the metal chelate compound include a compound 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. including.

The cross-linking agent (B) is usually 0.05 parts by mass or more and 5 parts by mass or less, preferably 0.1 parts by mass or more and 5 parts by mass or less, based on 100 parts by mass of the solid content of the resin (A) of the pressure-sensitive adhesive composition. It is contained in the ratio of. When the content of the cross-linking agent (B) is 0.05 parts by mass or more, the durability of the pressure-sensitive adhesive layer tends to be improved.

The cross-linking agent (B) is usually 0.05 parts by mass or more and 5 parts by mass or less, preferably 0.1 parts by mass, with respect to 100 parts by mass of the solid content of the resin (A) (the total of two or more types). It is contained in a proportion of 5 parts by mass or less. When the content of the cross-linking agent (B) is 0.05 parts by mass or more, the durability of the pressure-sensitive adhesive layer tends to be improved.

(Silane compound (C))
The pressure-sensitive adhesive composition contains a silane compound (C). The silane compound (C) may be used to improve the smoothness of the surface of the pressure-sensitive adhesive layer obtained by using the pressure-sensitive adhesive composition and to suppress uneven coating when the pressure-sensitive adhesive composition is applied. it can.

The silane compound (C) contains a Si—O—Si bond in the main chain, both ends of the main chain have a functional group other than a hydrolyzable group, and the side chain is a functional group other than a carboxyl group (-COOH). It has a group. The functional groups forming both ends of the main chain refer to the functional groups bonded to Si located at the ends of the Si—O—Si bond. The hydrolyzable group is a substituent that is directly bonded to a silicon atom and produces a silanol group (-SiOH) by a hydrolyzing reaction or a condensation reaction. Examples of the hydrolyzable group include a halogen atom, an alkoxy group, an acyloxy group, an alkenyloxy group and the like. When the hydrolyzable group has a carbon atom, the number of carbon atoms thereof is preferably 6 or less, and more preferably 4 or less. The functional group forming the side chain is a functional group bonded to Si located in the main chain. The pressure-sensitive adhesive composition may contain one or more silane compounds (C).

Both ends of the main chain of the silane compound (C) are not particularly limited as long as they have a functional group other than a hydrolyzable group, but for example, they are independently an alkyl group, an alkyl halide group, a phenyl group or, respectively. It preferably has an aralkyl group.

Examples of the alkyl group include an alkyl group having 1 to 6 carbon atoms. Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a sec-butyl group, a tert-butyl group, a pentyl group, a hexyl group and the like. Examples of the alkyl halide group include those in which one or more hydrogens contained in the alkyl group are replaced with halogen atoms such as a fluorine atom, a chlorine atom, a bromine atom and an iodine atom. Examples of the aralkyl group include an aralkyl group having 7 to 16 carbon atoms. Examples of the aralkyl group include a benzyl group, a phenethyl group, a naphthylmethyl group and a phenylpropyl group. Both ends of the main chain of the silane compound (C) are preferably alkyl groups independently, and both are preferably methyl groups.

The side chain of the silane compound (C) is not particularly limited as long as it has a functional group other than the functional group other than the carboxyl group, but for example, it is preferable that each of them independently has an alkyl group or an aralkyl group. As the alkyl group and the aralkyl group, those exemplified above can be used. The side chain of the silane compound (C) is more preferably an alkyl group, and even more preferably an alkyl group having 1 to 6 carbon atoms. It is preferable that any one of the side chains of the silane compound (C) contains a methyl group.

The silane compound (C) is not particularly limited as long as it has the above structure, but it is preferably used as a leveling agent. The viscosity of such a silane compound (C) at a temperature of 25 ° C. can usually be 300 mPa · s or more. The viscosity of the silane compound (C) is more preferably 500 mPa · s or more, further preferably 800 mPa · s or more, 1000 mPa · s or more, or 1100 mPa · s or more. Often, it may be 1200 mPa · s or more, or 2000 mPa · s or more. The viscosity of the silane compound at a temperature of 25 ° C. is usually 3000 mPa · s or less, and may be 2500 mPa · s or less. The viscosity of the silane compound (C) at a temperature of 25 ° C. can be measured according to the viscosity measuring method using a conical-plate type rotational viscometer of JIS Z8803.

As the silane compound (C), a commercially available product may be used. Specific examples of commercially available products include alkyl aralkyl-modified silicone oils "SH203", "SH230", "SF-8410", "SF-8416", "SH-8400", and "L" manufactured by Dow Toray Co., Ltd. -7001 ”and the like.

The silane compound (C) is usually 0. With respect to 100 parts by mass of the solid content of the resin (A) of the pressure-sensitive adhesive composition, from the viewpoint of the smoothness of the surface of the pressure-sensitive adhesive layer and the coatability of the pressure-sensitive adhesive composition. It is 01 parts by mass or more, preferably 0.1 parts by mass or more, more preferably 1 part by mass or more, and usually 10 parts by mass or less, preferably 5 parts by mass or less. It is more preferably 3 parts by mass or less, and further preferably 1 part by mass or less.

(Silane Coupling Agent (D))
The pressure-sensitive adhesive composition can include a silane coupling agent (D). When the pressure-sensitive adhesive composition contains the silane coupling agent (D), the heat resistance of the pressure-sensitive adhesive layer can be improved, and when the pressure-sensitive adhesive layer is bonded to a glass substrate, a conductive layer, or the like, the pressure-sensitive adhesive It becomes easy to improve the adhesion between the layer and the glass substrate, the conductive layer, etc., and the peeling resistance and the like can be improved.

The silane coupling agent (D) is preferably a compound other than the silane compound (C), in which an arbitrary functional group is bonded to a silicon atom. Examples of the functional group bonded to the silicon atom include a hydrolyzable group such as an alkoxy group, a vinyl group, an amino group, an epoxy group, an alkyl halide group, a (meth) acroyl group, and a reactive functional group such as a mercapto group. Examples thereof include organic groups having. The silane coupling agent (D) is preferably a siloxane compound containing a Si—O—Si bond in the main chain, and the siloxane compound preferably has a hydrolyzable group in the main chain. Examples of the hydrolyzable group include those described above, and an alkoxy group is preferable. The pressure-sensitive adhesive composition may contain one or more silane coupling agents (D).

Examples of the silane coupling agent (D) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, and N-. (2-Aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-) Epoxycyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane , 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropylethoxydimethylsilane and the like.

The silane coupling agent (D) may be of the silicone oligomer type. When the silicone oligomer is shown in the form of a (monomer) oligomer, for example, the following can be mentioned.

3-Mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer,
3-Mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer,
3-Mercaptopropyltriethoxysilane-tetramethoxysilane copolymer,
A mercaptopropyl group-containing copolymer such as 3-mercaptopropyltriethoxysilane-tetraethoxysilane copolymer;
Mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer,
Mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer,
Mercaptomethyltriethoxysilane-tetramethoxysilane copolymer,
Mercaptomethyl group-containing copolymers such as mercaptomethyltriethoxysilane-tetraethoxysilane copolymer;
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,
3-Glydoxypropyl group-containing copolymers such as 3-glycidoxypropylmethyldiethoxysilane-tetraethoxysilane copolymer;
3-Methoxyloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer,
3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer,
3-methacryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer,
3-methacryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer,
3-Methylloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer,
3-methacryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer,
3-Methacryloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer,
3-Methacloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymer or other copolymer containing a methacryloyloxypropyl group;
3-Acryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer,
3-Acryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer,
3-Acryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer,
3-Acryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer,
3-Acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer,
3-Acryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer,
3-Acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer,
Acryloyloxypropyl group-containing copolymers such as 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymer;
Vinyl Trimethoxysilane-Tetramethoxysilane Copolymer,
Vinyl Trimethoxysilane-Tetraethoxysilane Copolymer,
Vinyltriethoxysilane-tetramethoxysilane copolymer,
Vinyltriethoxysilane-tetraethoxysilane copolymer,
Vinylmethyldimethoxysilane-tetramethoxysilane copolymer,
Vinylmethyldimethoxysilane-tetraethoxysilane copolymer,
Vinylmethyldiethoxysilane-tetramethoxysilane copolymer,
Vinyl group-containing copolymers such as vinylmethyldiethoxysilane-tetraethoxysilane copolymer;
3-Aminopropyltrimethoxysilane-tetramethoxysilane copolymer,
3-Aminopropyltrimethoxysilane-tetraethoxysilane copolymer,
3-Aminopropyltriethoxysilane-tetramethoxysilane copolymer,
3-Aminopropyltriethoxysilane-tetraethoxysilane copolymer,
3-Aminopropylmethyldimethoxysilane-tetramethoxysilane copolymer,
3-Aminopropylmethyldimethoxysilane-tetraethoxysilane copolymer,
3-Aminopropylmethyldiethoxysilane-tetramethoxysilane copolymer,
Amino group-containing copolymers such as 3-aminopropylmethyldiethoxysilane-tetraethoxysilane copolymer.

The viscosity of the silane coupling agent (D) at a temperature of 25 ° C. is usually 250 mPa · s or less, preferably 200 mPa · s or less, may be 150 mPa · s or less, and is 100 mPa · s or less. It may be 30 mPa · s. The viscosity of the silane coupling agent (D) at a temperature of 25 ° C. can be measured according to the viscosity measuring method using a conical-plate type rotational viscometer of JIS Z8803.

The silane coupling agent (D) is usually 0.01 part by mass or more and 10 parts by mass or less, preferably 0.05 parts by mass or more and 5 parts by mass with respect to 100 parts by mass of the solid content of the resin (A) of the pressure-sensitive adhesive composition. It is contained in a proportion of less than a part. When the content of the silane coupling agent (D) is 0.01 parts by mass or more, the heat resistance of the pressure-sensitive adhesive layer formed by using the pressure-sensitive adhesive composition can be easily improved, and the pressure-sensitive adhesive layer and the glass substrate can be easily improved. It is easy to improve the adhesion with such things. When the content of the silane coupling agent (D) is 10 parts by mass or less, bleeding out of the silane coupling agent (D) from the pressure-sensitive adhesive layer can be suppressed.

(Other ingredients)
The pressure-sensitive adhesive composition can contain other components other than the resin (A), the cross-linking agent (B), the silane compound (C), and the silane coupling agent (D). Other components include one type of additive such as a cross-linking catalyst, an ultraviolet absorber, a weather stabilizer, a tack fire, a plasticizer, a softening agent, a dye, a pigment, an inorganic filler, a light scattering fine particle, and a tackifier. Two or more types can be included.

The pressure-sensitive adhesive composition is usually prepared as a pressure-sensitive adhesive liquid in which the compounding components are dissolved or dispersed by containing an organic solvent. The organic solvent is preferably selected according to the type of the resin (A). Specific examples of organic solvents include aromatic hydrocarbons such as toluene and xylene; aliphatic hydrocarbons such as hexane, heptane and pentane, and ketones such as methyl ethyl ketone and methyl isobutyl ketone; such as ethyl acetate and butyl acetate. Contains various esters. The concentration of the resin (A) in the pressure-sensitive adhesive liquid is usually 3 to 20% by mass.

<Adhesive layer>
The pressure-sensitive adhesive layer according to the present invention contains the above-mentioned pressure-sensitive adhesive composition according to the present invention, and typically comprises the pressure-sensitive adhesive composition according to the present invention. The pressure-sensitive adhesive layer can be obtained, for example, by dissolving or dispersing each component constituting the pressure-sensitive adhesive composition in a solvent to obtain a pressure-sensitive adhesive liquid, and applying and drying this pressure-sensitive adhesive liquid on the surface of an optical layer or a release film. Can be done.

The pressure-sensitive adhesive layer according to the present invention can have different adhesive forces to the release film on both sides thereof. Therefore, even in an adhesive sheet provided with a release film having the same release treatment layer on both sides of the adhesive layer, which will be described later, when the release film is peeled off, a portion having the adhesive layer is peeled off together with one release film. Then, the other part of the pressure-sensitive adhesive layer is peeled off together with the other release film, and the problem that the pressure-sensitive adhesive layer is partially separated can be suppressed. As a result, a uniform pressure-sensitive adhesive layer can be formed on an adherend member such as an optical layer or a glass substrate.

<Adhesive sheet>
The pressure-sensitive adhesive sheet according to the present invention is obtained by providing a release film having the same release treatment layer on both sides of the pressure-sensitive adhesive layer according to the present invention described above. The release film has a base film and a release treatment layer provided on at least one surface of the base film, and the release treatment layer side is bonded to the pressure-sensitive adhesive layer. With the release film having the same release treatment layer, the release treatment layer side of the release treatment film provided with the release treatment layer on the same substrate by the same release treatment was bonded to the same surface of the pressure-sensitive adhesive layer. Sometimes, it refers to a release film having the same peeling force.

In the pressure-sensitive adhesive sheet according to the present invention, the peeling force between one surface of the pressure-sensitive adhesive layer and the release-treated layer side of the release film is set as the first peeling force, and the side opposite to one surface of the pressure-sensitive adhesive layer. When the adhesive force between one other surface and the release treatment layer side of the release film is taken as the second release force, the first release force and the second release force are not the same but different from each other. The adhesive layers described above have different adhesive forces to the release film on both sides thereof. Therefore, even if a release film having different release treatment layers is not prepared, an adhesive sheet having different first release force and second release force can be obtained by using the release film having the same release treatment layer. Can be done. As a result, it is possible to suppress a problem that the pressure-sensitive adhesive layer is partially separated when the release film is peeled off from the pressure-sensitive adhesive sheet. The first peeling force and the second peeling force can be measured by the method described in Examples.

For the pressure-sensitive adhesive sheet, for example, the pressure-sensitive adhesive solution is applied and dried on the release-treated surface side of the release film to form a pressure-sensitive adhesive layer, and a release film is formed on the surface of the pressure-sensitive adhesive layer opposite to the release film. Can be obtained by laminating the release-processed surface side of the above. In this case, the peeling force between the release film laminated on the pressure-sensitive adhesive layer and the pressure-sensitive adhesive layer tends to be larger than the peeling force between the release film coated with the pressure-sensitive adhesive liquid and the pressure-sensitive adhesive layer. is there.

The first peeling force and the second peeling force are preferably 0.010 N / 50 mm or more, more preferably 0.020 N / 50 mm or more, and further preferably 0.030 N / 50 mm or more, respectively. Further, it is preferably 0.1 N / 50 mm or less, more preferably 0.08 N / 50 mm or less, and may be 0.06 N / 50 mm or less. The absolute value of the difference between the first peeling force and the second peeling force is preferably 0.01 N / 50 mm or more, more preferably 0.012 N / 50 mm or more, and 0.015 N / 50 mm or more. It may be 0.09 N / 50 mm or less, may be 0.08 N / 50 mm or less, or may be 0.06 N / 50 mm or less.

Examples of the release film used for the pressure-sensitive adhesive sheet include a film formed by using a resin and subjected to a mold release treatment. The resin forming the base film is not particularly limited, and examples thereof include polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and polyarate. Further, as the mold release treatment applied to the base film, a known mold release treatment may be performed, but a method of coating the base film with a release agent such as a fluorine compound or a silicone compound is preferable.

<Optical laminate>
FIG. 1 is a schematic cross-sectional view showing an example of an optical laminate according to the present invention. 2 and 3 are schematic cross-sectional views showing an example of an optical layer included in the optical laminate according to the present invention. 4 to 8 are schematic cross-sectional views showing another example of the layer structure of the optical laminate according to the present invention.

The optical laminate according to the present invention includes an optical layer and the above-mentioned pressure-sensitive adhesive layer according to the present invention. Since the pressure-sensitive adhesive layer can have different adhesions to the release film on both sides of the pressure-sensitive adhesive sheet, it is possible to provide a uniform pressure-sensitive adhesive layer on the optical laminate by using the pressure-sensitive adhesive sheet. it can.

For example, as shown in FIG. 1, the optical laminate 1 includes an adhesive layer 20 on at least one surface of the optical layer 10, and may have adhesive layers 20 on both sides of the optical layer 10. .. When the pressure-sensitive adhesive layer 20 is provided on the surface of the optical layer 10, a primer layer is formed on the bonding surface of the optical layer 10 and / or the bonding surface of the pressure-sensitive adhesive layer 20, and a surface activation treatment such as plasma treatment is performed. Corona treatment and the like are preferable, and corona treatment is more preferable.

The optical layer 10 may be a polarizing plate having a resin film on one side or both sides of the polarizer. That is, as shown in FIG. 2, the optical layer 10 may be a single-sided protective polarizing plate 10a having the first resin film 3 on one side of the polarizing element 2, and as shown in FIG. 3, one of the polarizing elements 2. A double-sided protective polarizing plate 10b having a first resin film 3 on one surface and a second resin film 4 on the other surface may be used. In the single-sided protective polarizing plate 10a shown in FIG. 2, the pressure-sensitive adhesive layer 20 is usually laminated on the polarizer surface, that is, the surface of the polarizing element 2 opposite to the first resin film 3. The pressure-sensitive adhesive layer 20 is preferably laminated directly on the polarizer 2. In the double-sided protective polarizing plate 10b shown in FIG. 3, the pressure-sensitive adhesive layer 20 may be laminated on the outer surface of either the first resin film 3 or the second resin film 4, or may be laminated on both outer surfaces. Good.

The optical laminate 1 shown in FIG. 1 may include a separator (release film) laminated on the outer surface of the pressure-sensitive adhesive layer 20. This separator is usually peeled off and removed when the pressure-sensitive adhesive layer 20 is used (for example, when it is laminated on an adherend member such as a conductive layer or a glass substrate). The separator may be the same as the release film described above, or may be one of the two release films of the pressure-sensitive adhesive sheet.

The optical laminate 1 forms the pressure-sensitive adhesive layer 20 by applying and drying the above-mentioned pressure-sensitive adhesive liquid (a solution in which each component constituting the pressure-sensitive adhesive composition is dissolved or dispersed in a solvent) on the surface of the optical layer 10. Can be obtained by The optical laminate 1 can also be formed by forming an adhesive layer 20 on the release-treated surface of the release film in the same manner as described above, and laminating (transferring) the adhesive layer 20 on the surface of the optical layer 10. Obtainable.

Further, the optical laminates 5 and 6 shown in FIGS. 4 and 5 have an optical layer 10 (single-sided protective polarizing plate 10a, double-sided protective polarizing plate 10b), an adhesive layer 20, and a conductive layer 30 in this order. .. The optical laminate 5 shown in FIG. 4 is an example in which the single-sided protective polarizing plate 10a shown in FIG. 2 is used as the optical layer 10, and the optical laminate 6 shown in FIG. 5 is a double-sided protective polarizing plate 10b shown in FIG. This is an example used as the optical layer 10. The pressure-sensitive adhesive layers 20 of the optical laminates 5 and 6 shown in FIGS. 4 and 5 are laminated on the conductive layer 30 so as to be in direct contact with the conductive layer 30. The optical laminates 5 and 6 may have a substrate 40 on the side of the conductive layer 30 opposite to the adhesive layer 20. The substrate 40 is, for example, a glass substrate or a resin film, as will be described later.

In the optical laminate 7 shown in FIG. 6, the optical laminate 1 shown in FIG. 1 is laminated on the conductive layer 30 via the resin layer 50. The pressure-sensitive adhesive layer 20 is in direct contact with the resin layer 50. The optical laminate 7 may have a substrate 40 on the side of the conductive layer 30 opposite to the adhesive layer 20.

The optical laminate 8 shown in FIG. 7 is the same as the optical laminate 7 shown in FIG. 6 except that it does not have the resin layer 50 and the conductive layer 30. In this case, the pressure-sensitive adhesive layer 20 is laminated on the substrate 40.

The optical laminate shown in FIG. 8 is the same as the optical laminate 7 shown in FIG. 6, except that the conductive layer 30 is patterned in a predetermined shape. The conductive layer 30 of the optical laminate shown in FIG. 8 can be used, for example, as a metal wiring layer (that is, an electrode layer) of a touch input element included in a touch input type liquid crystal display device. The resin layer 50 may be omitted in the optical laminate shown in FIG. When the pressure-sensitive adhesive layer 20 is laminated on the patterned conductive layer 30, the pressure-sensitive adhesive layer 20 may have a portion that is not in contact with the conductive layer 30.

The above-mentioned optical laminate can be used in an image display device such as a liquid crystal display device or an organic electroluminescence (EL) display device. The liquid crystal display device or the organic EL display device may be a touch input type display device having a touch panel function.

(Optical layer)
The optical layer may be various optical films (films having optical characteristics) that can be incorporated into an image display device such as a liquid crystal display device. Examples of the optical layer include a polarizer, a polarizing plate, a retardation film, a brightness improving film, an antiglare film, an antireflection film, a diffusion film, a light collecting film and the like. The optical layer may have a single-layer structure or a multi-layer structure.

(Polarizer)
The polarizer is a layer or film having a function of selectively transmitting linearly polarized light in a certain direction from natural light. Examples of the polarizer include a film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film. Examples of the dichroic dye include iodine and a dichroic organic dye. Further, the polarizing element may be a coating type polarizing film in which a dichroic dye in a Riotrovic liquid crystal state is coated on a base film and oriented and immobilized. These polarizers are called absorption type polarizers because they selectively transmit linearly polarized light in one direction from natural light and absorb linearly polarized light in the other direction.

The polarizer is not limited to the absorption type polarizer, but is a reflection type polarizer that selectively transmits linearly polarized light in one direction from natural light and reflects the linearly polarized light in the other direction, or a linearly polarized light in the other direction. A scattering type polarizer may be used, but an absorption type polarizer is preferable from the viewpoint of excellent visibility. Of these, a polyvinyl alcohol-based polarizing film composed of a polyvinyl alcohol-based resin film is more preferable, and a polyvinyl alcohol-based polarizing film in which a bicolor dye such as iodine or a bicolor dye is adsorbed and oriented on the polyvinyl alcohol-based resin film is preferable. More preferably, a polyvinyl alcohol-based polarizing film in which iodine is adsorbed and oriented on the polyvinyl alcohol-based resin film is particularly preferable.

As the polyvinyl alcohol-based resin, a saponified polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate and another monomer copolymerizable with the vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is usually 85 mol% or more and 100 mol% or less, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can be used. The average degree of polymerization of the polyvinyl alcohol-based resin is usually 1000 or more and 10000 or less, preferably 1500 or more and 5000 or less. The average degree of polymerization of the polyvinyl alcohol-based resin can be determined in accordance with JIS K 6726: 1994.

A film formed of such a polyvinyl alcohol-based resin is used as a raw film for a polarizing film composed of a polyvinyl alcohol-based resin film. The method for forming a film of the polyvinyl alcohol-based resin is not particularly limited, and a known method is adopted. The thickness of the polyvinyl alcohol-based raw film is, for example, 150 μm or less, preferably 100 μm or less (for example, 50 μm or less), and 5 μm or more.

A polarizing film composed of a polyvinyl alcohol-based resin film can be produced by a known method. Specifically, the step of uniaxially stretching the polyvinyl alcohol-based resin film; the step of adsorbing the dichroic dye by dyeing the polyvinyl alcohol-based resin film with the dichroic dye; the polyvinyl alcohol on which the dichroic dye is adsorbed. It can be produced by a method including a step of treating (crosslinking) the based resin film with an aqueous boric acid solution; and a step of washing with water after the treatment with the aqueous boric acid solution.

The thickness of the polarizer can be 40 μm or less, preferably 30 μm or less (for example, 20 μm or less, further 15 μm or less, and further 10 μm or less or 8 μm or less). According to the methods described in JP-A-2000-338329 and JP-A-2012-159778, a thin-film polarizer can be more easily produced, and the thickness of the polarizer can be, for example, 20 μm or less, further 15 μm. Below, it becomes easier to make it 10 μm or less or 8 μm or less. The thickness of the polarizer is usually 2 μm or more. Reducing the thickness of the polarizer is advantageous for reducing the thickness of the optical laminate including the polarizing plate and the image display device including the polarizing plate.

(1st and 2nd resin films)
The first resin film 3 and the second resin film 4 are provided on the polarizer 2, and may be, for example, a protective film for protecting the polarizer 2, or may have an optical function such as a retardation film described later. It may be a protective film that also has. The first resin film 3 and the second resin film 4 are each a translucent (preferably optically transparent) thermoplastic resin, for example, a chain polyolefin resin (polypropylene resin or the like) or a cyclic polyolefin resin. Polyethylene-based resins such as resins (norbornen-based resins); cellulose ester-based resins such as triacetyl cellulose and diacetyl cellulose; polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polycarbonate resins; (meth) acrylic A film made of a based resin; a polystyrene resin; or a mixture thereof, a copolymer, or the like can be used.

The first resin film 3 and the second resin film 4 may be either a non-stretched 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 biaxial stretching is performed in a second direction different from that in the first direction.

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.

Cyclic polyolefin resin is a general term for resins containing norbornene, tetracyclododecene (also known as dimethanooctahydronaphthalene), or a cyclic olefin such as a derivative thereof as a polymerization unit. The cyclic polyolefin resin includes a ring-opening (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 an aromatic compound having a vinyl group. Examples thereof include copolymers of the above, and modified (co) copolymers obtained by modifying these with unsaturated carboxylic acids or derivatives thereof. Of these, a norbornene-based resin using a norbornene-based monomer such as norbornene or a polycyclic norbornene-based monomer is preferably used as the cyclic olefin.

The cellulose ester-based resin is a resin in which at least a part of the hydroxyl groups in cellulose is acetic acid esterified, and a mixed ester in which a part is acetic acid esterified and a part is esterified with another acid. May be good. The cellulosic ester resin is preferably an acetyl cellulosic resin. Examples of the acetyl cellulosic resin include triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate.

The polyester resin is a resin other than the above cellulose ester 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. Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethylterephthalate, and polycyclohexanedimethylnaphthalate. Of these, polyethylene terephthalate is preferably used from the viewpoints of mechanical properties, solvent resistance, scratch resistance, cost and the like. Polyethylene terephthalate refers to a resin in which 80 mol% or more of the repeating unit is composed of ethylene terephthalate, and is a constituent unit derived from other copolymerization components (dicarboxylic acid component such as isophthalic acid; diol component such as propylene glycol). May include.

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. Examples of polycarbonate include 2,2-bis (4-hydroxyphenyl) propane (also known as bisphenol A), 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) cyclohexane, and 1, Examples thereof include polycarbonate derived from bisphenols such as 1-bis (4-hydroxyphenyl) isobutane and 1,1-bis (4-hydroxyphenyl) ethane.

The (meth) acrylic resin is a polymer containing a structural unit derived from the (meth) acrylic monomer, and examples of the (meth) acrylic monomer include methacrylic acid ester and acrylic acid ester.

Examples of the methacrylic acid ester include methyl methacrylate, ethyl methacrylate, n-, i- or t-butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate. And so on.

Examples of the acrylic acid ester include ethyl acrylate, n-, i- or t-butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate and the like. ..

The (meth) acrylic resin may be a polymer consisting of only structural units derived from the (meth) acrylic monomer, or may contain other structural units.

In one preferred embodiment, the (meth) acrylic resin contains methyl methacrylate as a copolymerization component, or contains methyl methacrylate and methyl acrylate. In one preferred embodiment, the (meth) acrylic resin can be a polymer containing a methacrylic acid ester as a main monomer (containing 50% by mass or more), and the methacrylic acid ester and other copolymerization components. Is preferably a copolymer in which is copolymerized.

The glass transition temperature of the (meth) acrylic resin is preferably 80 ° C. or higher and 160 ° C. or lower. The glass transition temperature is the polymerization ratio of the methacrylic acid ester-based monomer and the acrylic acid ester-based monomer, the carbon chain length of each ester group, the type of functional group having them, and the polyfunctional monomer for the entire monomer. It can be controlled by adjusting the polymerization ratio of the monomer.

It is also effective to introduce a ring structure into the main chain of the polymer as a means for raising the glass transition temperature of the (meth) acrylic resin. The ring structure is preferably a heterocyclic structure such as a cyclic acid anhydride structure, a cyclic imide structure and a lactone structure. Specific examples thereof include a cyclic acid anhydride structure such as a glutaric anhydride structure and a succinic anhydride structure; a cyclic imide structure such as a glutarimide structure and a succinic anhydride structure; and a lactone ring structure such as butyrolactone and valerolactone. As the content of the ring structure in the main chain is increased, the glass transition temperature of the (meth) acrylic resin tends to be increased. The cyclic acid anhydride structure and the cyclic imide structure are introduced by copolymerizing a monomer having a cyclic structure such as maleic anhydride and maleimide; the cyclic acid anhydride structure is formed by a dehydration / demethanol condensation reaction after polymerization. Method of introduction; It can be introduced by a method of reacting an amino compound to introduce a cyclic imide structure or the like. For a resin (polymer) having a lactone ring structure, after preparing a polymer having a hydroxyl group and an ester group in a polymer chain, the hydroxyl group and the ester group in the obtained polymer are required by heating. Therefore, it can be obtained by a method of forming a lactone ring structure by cyclization condensation in the presence of a catalyst such as an organic phosphorus compound.

The (meth) acrylic resin and the thermoplastic resin film formed from the (meth) acrylic resin may contain an additive if necessary. Examples of the additive include a lubricant, an antiblocking agent, a heat stabilizer, an antioxidant, an antistatic agent, a lightproofing agent, an impact resistance improving agent, a surfactant and the like. These additives can also be used when a thermoplastic resin other than the (meth) acrylic resin is used as the thermoplastic resin constituting the thermoplastic resin film.

The (meth) acrylic resin may contain acrylic rubber particles which are impact improving agents 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 consisting of only this elastic polymer, or one elastic polymer. Examples thereof include a multi-layer structure having layers.

Examples of the above-mentioned elastic polymer include a crosslinked elastic copolymer containing alkyl acrylate as a main component and copolymerizing another copolymerizable vinyl-based monomer and a crosslinkable monomer. Examples of the alkyl acrylate that is the main component of the elastic polymer include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and the like, which have an alkyl group having 1 or more and 8 or less carbon atoms. An alkyl acrylate having an alkyl group having 4 or more carbon atoms is preferably used.

Examples of the other vinyl-based monomer copolymerizable with the alkyl acrylate include a compound having one polymerizable carbon-carbon double bond in the molecule, and more specifically, methyl methacrylate. Methacrylic acid ester such as; aromatic vinyl compound such as styrene; vinyl cyan compound such as acrylonitrile and the like.

Examples of the crosslinkable monomer include a crosslinkable compound having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, ethylene glycol di (meth) acrylate and butane. Examples thereof include (meth) acrylates of polyhydric alcohols such as diol di (meth) acrylate; alkenyl esters of (meth) acrylic acid such as allyl (meth) acrylate; and divinylbenzene.

A laminate of a film made of a (meth) acrylic resin containing no rubber particles and a film made of a (meth) acrylic resin containing rubber particles is used as a thermoplastic resin film to be bonded to the optical layer 10. You can also. Further, a (meth) acrylic resin layer is formed on one side or both sides of a retardation-developing layer made of a resin different from the (meth) acrylic resin, and the one in which the retardation is expressed is bonded to the optical layer 10. It can also be a thermoplastic resin film.

The first resin film 3 and the second resin film 4 are films containing one or more thermoplastic resins selected from the group consisting of a cellulose ester resin, a polyester resin, a (meth) acrylic resin, and a cyclic polyolefin resin, respectively. Is preferable, and a cellulose ester-based resin film, a polyester-based resin film, a (meth) acrylic-based resin film, or a cyclic polyolefin-based resin film is more preferable.

The first resin film 3 and / or the second resin film 4 contains an ultraviolet absorber, an infrared absorber, an organic dye, a pigment, an inorganic pigment, an antioxidant, an antistatic agent, a surfactant, a lubricant, a dispersant, and heat. It may contain a stabilizer or the like. When the optical laminate is applied to an image display device, a thermoplastic resin film containing an ultraviolet absorber is placed on the visual side of an image display element (for example, a liquid crystal cell or an organic EL display element) to display the image. Deterioration due to ultraviolet rays can be suppressed. Examples of the ultraviolet absorber include salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, nickel complex salt compounds and the like.

The first resin film 3 and the second resin film 4 may be films made of the same thermoplastic resin, or may be films made of different thermoplastic resins. The first resin film 3 and the second resin film 4 may be the same or different in terms of thickness, presence / absence of additives, their types, retardation characteristics, and the like.

The first resin film 3 and / or the second resin film 4 has a hard coat layer, an antiglare layer, an antireflection layer, a light diffusion layer, an antistatic layer, and an antistatic layer on the outer surface (the surface opposite to the optical layer 10). A surface treatment layer (coating layer) such as a dirty layer or a conductive layer, or a protective film may be provided. The protective film is a film used for the purpose of protecting the surface of the optical layer 10 such as a polarizing plate from scratches and stains, and after the optical laminate 1 shown in FIG. 1 is bonded onto, for example, a conductive layer or a glass substrate. , It is customary to peel 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.

The thickness of the first resin film 3 and the second resin film 4 is usually 5 μm or more and 200 μm or less, preferably 10 μm or more and 120 μm or less, more preferably 10 μm or more and 85 μm or less, and further preferably 15 μm or more and 65 μm or less. The thickness of the first resin film 3 and the second resin film 4 may be 50 μm or less, or 40 μm or less, respectively. Reducing the thickness of the first resin film 3 and the second resin film 4 is advantageous for reducing the thickness of the optical laminate (polarizing plate) and the image display device including the optical laminate (polarizing plate).

The first resin film 3 and the second resin film 4 can be bonded to the polarizer 2 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 conventional water-based adhesives (for example, an adhesive composed of an aqueous polyvinyl alcohol-based resin solution, a water-based two-component urethane-based emulsion adhesive, an aldehyde compound, an epoxy compound, a melamine-based compound, a methylol compound, and an isocyanate compound. (Amine compounds, cross-linking agents such as polyvalent metal salts, etc.) can be mentioned. Of these, an aqueous adhesive composed of an aqueous solution of a polyvinyl alcohol-based resin can be preferably used. When a water-based adhesive is used, the polarizer 2 is bonded to the first resin film 3 and / or the second resin film 4, and then dried to remove water contained in the water-based adhesive. It is preferable to carry out the step of causing. 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 means 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, a photoreaction. Examples thereof include a curable composition containing a sex resin, a curable composition containing a binder resin and a photoreactive cross-linking agent, and an ultraviolet curable adhesive is preferable.

When an active energy ray-curable adhesive is used, the polarizer 2 is bonded to the first resin film 3 and / or the second resin film 4, and then a drying step is performed if necessary, and then the active energy ray is applied. A curing step is performed in which the active energy ray-curable adhesive is cured by irradiating with. The light source of the active energy rays is not particularly limited, but ultraviolet rays having an emission distribution having a wavelength of 400 nm or less are preferable.

As a method of bonding the polarizer 2 and the first resin film 3 and / or the second resin film 4, the surface of at least one of these bonded surfaces is saponified, corona-treated, plasma-treated, or the like. Examples thereof include a method of performing an activation treatment. When resin films are bonded to both sides of the polarizer 2, the adhesive for bonding these resin films may be the same type of adhesive or different types of adhesive.

(Phase difference film)
As the retardation film, a stretched film obtained by uniaxially stretching or biaxially stretching a translucent thermoplastic resin; a film in which a liquid crystal compound such as a discotic liquid crystal or a nematic liquid crystal is oriented and fixed; the above-mentioned above on a base film. Examples thereof include those having a liquid crystal layer formed. Further, in the present specification, the zero retardation film is also included in the retardation film. The base film is usually a film made of a thermoplastic resin, and an example of the thermoplastic resin is a cellulosic ester-based resin such as triacetyl cellulose. Examples of the translucent thermoplastic resin include the resins constituting the first resin film 3 and the second resin film 4 described above.

The zero retardation film refers to a film in which both the in-plane retardation value Re and the thickness direction retardation value Rth are -15 to 15 nm. This retardation film is suitably used for a liquid crystal display device in IPS mode. The in-plane retardation value Re and the thickness direction retardation value Rth 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 referred to here are values at a wavelength of 590 nm.

The in-plane retardation value Re and the thickness direction retardation value Rth are expressed by the following equations, respectively:
Re = (n _{x −} n _y ) × d
Rth = [(n _x + n _y ) / 2-n _z ] x d
Defined in. Wherein, n _x is a refractive index in a slow axis direction (x-axis direction) in the film plane, n _y is the fast axis direction in the film plane of the (y-axis direction orthogonal to the x-axis in a plane) It is the refractive index, _nz is the refractive index in the film thickness direction (the z-axis direction perpendicular to the film surface), and d is the film thickness.

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.

As a film that expresses optical anisotropy by coating and orientation of a liquid crystal compound,
First form: a retardation film in which a rod-shaped liquid crystal compound is oriented horizontally with respect to a supporting substrate.
Second form: a retardation film in which the rod-shaped liquid crystal compound is oriented perpendicular to the supporting substrate,
Third form: A retardation film in which the rod-shaped liquid crystal compound changes its orientation spirally in the plane.
Fourth form: a retardation film in which a disk-shaped liquid crystal compound is inclined or oriented,
Fifth form: A biaxial retardation film in which a disk-shaped liquid crystal compound is oriented perpendicularly to a supporting substrate.

For example, as the optical layer used in the organic electroluminescence display, the first form, the second form, and the fifth form are preferably used. Alternatively, these may be laminated and used.

When the retardation film is a layer made of a polymer in the oriented state of the polymerizable liquid crystal compound (hereinafter, may be referred to as an "optical anisotropic layer"), the retardation film may have anti-wavelength dispersibility. preferable. The inverse wavelength dispersibility is an optical characteristic in which the liquid crystal alignment in-plane retardation value at a short wavelength is smaller than the liquid crystal alignment in-plane retardation value at a long wavelength, and the retardation film is preferably expressed by the following formula. (1) and equation (2) are satisfied. Re (λ) represents an in-plane retardation value with respect to light having a wavelength of λ nm.
Re (450) / Re (550) ≤ 1 (1)
1 ≦ Re (630) / Re (550) (2)
When the retardation film is in the first form and has anti-wavelength dispersibility, it is preferable because the coloring at the time of black display on the display device is reduced, and 0.82 ≦ Re (450) / Re (550) in the formula (1). ) ≤ 0.93 is more preferable. Further, 120 ≦ Re (550) ≦ 150 is preferable.

When the retardation film is a film having an optically anisotropic layer, the polymerizable liquid crystal compound is described in "3" of the Liquid Crystal Handbook (edited by the Liquid Crystal Handbook Editorial Committee, published on October 30, 2000 by Maruzen Co., Ltd.). Among the compounds described in ".8.6 Network (completely crosslinked type)" and "6.5.1 Liquid crystal material b. Polymerizable nematic liquid crystal material", compounds having a polymerizable group, and Japanese Patent Application Laid-Open No. 2010-31223 The polymerizable liquid crystal compound described in JP-A-2010-270108, JP-A-2011-6360, JP-A-2011-207765, JP-A-2016-81035, and International Publication No. 2017/043438. Can be mentioned.

Examples of the method for producing a retardation film from a polymer in an oriented state of a polymerizable liquid crystal compound include the method described in JP-A-2010-31223.

In the case of the second embodiment, the in-plane retardation value Re (550) may be adjusted in the range of 0 to 10 nm, preferably in the range of 0 to 5 nm, and the phase difference value Rth in the thickness direction is −10 to −−. It may be adjusted in the range of 300 nm, preferably in the range of −20 to −200 nm. The phase difference value Rth in the thickness direction, which means the refractive index anisotropy in the thickness direction, is the phase difference value R50 and the in-plane phase difference value Re, which are measured by inclining 50 degrees with the in-plane phase advance axis as the inclination axis. Can be calculated from. That is, the retardation value Rth in the thickness direction is the in-plane retardation value Re, the retardation value R50 measured by inclining 50 degrees with the phase advance axis as the tilt axis, the thickness d of the retardation film, and the retardation film. From the average refractive index n ₀ , n _x , _ny and n _z can be obtained by the following equations (4) to (6), and these can be substituted into the equation (3) for calculation.

Rth = [(n _x + n _y ) / 2- _nz ] x d (3)
Re = (n _{x −} n _y ) × d (4)
R50 = (n _{x −} n _y ') × d / cos (φ) (5)
(n _x + n _y + n _z ) / 3 = n ₀ (6)
here,
φ = sin ^-1 [sin (40 °) / n ₀ ]
n _y '= n _y x n _z / [ _ny ² x sin ² (φ) + n _z ² x cos ² (φ)] ^1/2

The retardation film may be a multilayer film having two or more layers. For example, a protective film is laminated on one side or both sides of a retardation film, and two or more retardation films are laminated via an adhesive or an adhesive.

(Conductive layer)
Examples of the conductive layer 30 include a transparent electrode layer and a metal layer. The transparent electrode layer includes a layer composed of indium tin oxide, tin oxide, indium oxide, zinc oxide, titanium oxide, gallium oxide, aluminum oxide, zinc oxide, zinc oxide, zinc oxide, zinc oxide, and a mixture thereof. Can be mentioned. ITO is preferable in terms of conductivity and visible light transmittance. As the metal layer, one metal simple substance selected from the group consisting of aluminum, copper, silver, iron, tin, zinc, nickel, molybdenum, chromium, tungsten, and lead, and two kinds selected from these groups. Examples thereof include a layer containing at least one of at least one selected from the alloys containing the above metal elements. Of these, from the viewpoint of conductivity, it is preferably a metal layer containing at least one metal simple substance selected from aluminum, copper, silver and gold, and more preferably at least one selected from aluminum, copper and silver. A layer containing elemental metal of a species.

The conductive layer 30 may be a layer in which a metal mesh in which a thin metal wiring layer is arranged on a substrate, metal nanoparticles, or metal nanowires are added to a binder.

The method for preparing the conductive layer 30 is not particularly limited, and it may be formed by a vacuum deposition method, a sputtering method, an ion plating method, an inkjet printing method, or a gravure printing method. The conductive layer 30 is preferably a transparent electrode layer and a metal layer formed by a sputtering method, an inkjet printing method or a gravure printing method, and more preferably a transparent electrode layer and a metal layer formed by sputtering. The thickness of the conductive layer 30 is not particularly limited, but is usually 3 μm or less, preferably 1 μm or less, more preferably 0.8 μm or less, and usually 0.01 μm or more. Further, when the conductive layer 30 is a metal wiring layer (for example, a metal mesh), the line width of the metal wiring is usually 10 μm or less, preferably 5 μm or less, more preferably 3 μm or less, and usually 0.5 μm or more. Is.

(substrate)
The substrate 40 may be a transparent substrate included in the touch input element, and is preferably a glass substrate or a resin film. As the material of the glass substrate, soda lime glass, low-alkali glass, non-alkali glass and the like can be used. Examples of the resin constituting the resin film include the resins constituting the first resin film 3 and the second resin film 4 described above.

(Resin layer)
Examples of the resin forming the resin layer 50 include the resin constituting the first resin film and the second resin film described above. Further, the resin layer 50 may be a cured product layer of a curable resin. As the curable resin capable of forming the resin layer 50, known curable resins can be used, and examples thereof include those described in JP-A-2009-217307.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" and "part" in Examples and Comparative Examples are mass% and parts by mass.

[Confirmation of peeling state and measurement of peeling force]
Using the pressure-sensitive adhesive sheets obtained in each Example and Comparative Example, the peeling state was confirmed and the peeling force was measured by the following procedure.

(Preparation of test piece)
The pressure-sensitive adhesive sheets obtained in each Example and Comparative Example were cured under the conditions of a temperature of 23 ° C. and a humidity of 55% RH for 1 week. A test piece having a width of 5 cm and a length of 12 cm was cut out from the cured adhesive sheet using a super cutter.

(Measurement of the first peeling force between the adhesive layer and the release treatment layer side of the first release film)
Double-sided tape (Nystack (trade name), manufactured by Nichiban Co., Ltd.) with a width of 25 mm and a length of 22 cm is attached to the entire surface of one side of a glass substrate (EAGLE XG, manufactured by Corning) in parallel in the long side direction. The side opposite to the pressure-sensitive adhesive layer of the second release film (release film provided so as to cover the pressure-sensitive adhesive layer coated and formed on the first release film) of the test piece prepared above is bonded to both sides. The tape and the glass substrate were bonded together. In this state, using an autograph (AGS-50NX, manufactured by Shimadzu Corporation), one end in the length direction of the first release film (the release film on the side to which the adhesive composition is applied when producing the adhesive sheet). (One side with a width of 5 cm) was grasped and pulled in the 180 ° direction at a peeling speed of 300 mm / min under the conditions of a temperature of 23 ° C. and a humidity of 55% RH to peel off from the adhesive layer, and the peeling force at that time was recorded on a chart. 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% of the intermediate part, which is relatively stable. It was calculated and used as the first peeling force [N / 50 mm].

(Measurement of the second peeling force between the adhesive layer and the release treatment layer side of the second release film)
The first release film was peeled off from the test piece prepared above, and the exposed pressure-sensitive adhesive layer and a glass substrate (EAGLE XG, manufactured by Corning Inc.) were bonded together. In this state, the peeling force was recorded on the chart in the same procedure as the measurement of the first peeling force except that the second peeling film was peeled off, and the second peeling force [N / 50 mm] was recorded based on the obtained data. ] Was calculated.

(Calculation of peeling force difference)
The absolute value of the difference between the first peeling force and the second peeling force obtained above was defined as the peeling force difference [N / 50 mm].

(Confirmation of peeling state)
When measuring the peeling force, the peeling state was visually confirmed. The case where the release film could be peeled off without partially separating the pressure-sensitive adhesive layer was evaluated as A, and the case where the pressure-sensitive adhesive layer was separated by the peeling of the release film was evaluated as B.

<Manufacturing Examples 1 and 2: (Metal) Acrylic Resin Production>
In a reaction vessel equipped with a cooling tube, a nitrogen introduction tube, a thermometer and a stirrer, a monomer having the composition shown in Table 1 (the numerical value in Table 1 is a mass part) is mixed with 81.8 parts of ethyl acetate. The obtained solution was charged. After replacing the air in the reaction vessel with nitrogen gas, the internal temperature was adjusted to 60 ° C. Then, a solution prepared by dissolving 0.12 parts of azobisisobutyronitrile in 10 parts of ethyl acetate was added. After maintaining the internal temperature at 54 to 56 ° C. until 12 hours have passed since the addition of azobisisobutyronitrile, ethyl acetate was added to adjust the polymer concentration to 20%, and the (meth) acrylic was adjusted. An ethyl acetate solution of the based resin was obtained.

The weight average molecular weight Mw and the number average molecular weight Mn of the (meth) acrylic resin (A1) obtained in Production Example 1 and the (meth) acrylic resin (A2) obtained in Production Example 2 were measured. For the weight average molecular weight Mw and the number average molecular weight Mn, four "TSKgel XL" manufactured by Toso Co., Ltd. and one "Shadex GPC KF-802" manufactured by Showa Denko Co., Ltd. are used as columns in the GPC apparatus. A total of 5 bottles were arranged in series, using tetrahydrofuran as an eluent, and measured by standard polystyrene conversion under the conditions of a sample concentration of 5 mg / mL, a sample introduction amount of 100 μL, a temperature of 40 ° C., and a flow velocity of 1 mL / min.

The abbreviations in the "Monomer Composition" column of Table 1 mean the following monomers.
BA: n-Butyl acrylate MA: Methyl acrylate HEA: 2-Hydroxyethyl acrylate AA: BMAA acrylate: Butoxymethylacrylamide PEA: 2-Phenoxyethyl acrylate

[Examples 1 to 10, Comparative Example 1]
(1) Preparation of Adhesive Composition Table 2 shows in an ethyl acetate solution (resin concentration: 20%) of the (meth) acrylic resin obtained in the above production example with respect to 100 parts of the solid content of the solution. The cross-linking agent (B), the silane compound (C), the silane coupling agent (D), and other components are mixed in the amounts (parts by mass) shown in Table 2 so that the solid content concentration becomes 14%. Ethyl acetate was added to obtain a pressure-sensitive adhesive composition. When the product used contains a solvent or the like, the amount of each compounded ingredient shown in Table 2 is the number of parts by mass as an active ingredient contained therein.

Details of each compounding ingredient shown by abbreviation in Table 2 are as follows.
(Crosslinking agent (B))
B: Coronate L (ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate: solid content concentration 75% by mass, manufactured by Tosoh Corporation)
(Silane compound (C))
C1: Alkyl aralkyl-modified silicone oil, trade name "SH203" obtained from Dow Toray Co., Ltd., contains Si—O—Si bond in the main chain, both ends of the main chain are methyl groups, and side chains Is a compound that is a methyl group or an alkyl group (viscosity: 1208 mPa · s)
C2: Alkyl aralkyl-modified silicone oil, trade name "SH230" obtained from Dow Toray Co., Ltd., contains Si—O—Si bond in the main chain, both ends of the main chain are methyl groups, and side chains Is a compound that is a methyl group or an alkyl group (viscosity: 1348 mPa · s)
(Silane Coupling Agent (D))
D1: 3-glycidoxypropyltrimethoxysilane, trade name "KBM403" obtained from Shin-Etsu Chemical Co., Ltd. (viscosity: 4.2 mPa · s)
D2: X-41-1810 (mercapto equivalent 450 g / mol) obtained from Shinetsu Kogyo Co., Ltd. (viscosity: 7.6 mPa · s)
(Other ingredients)
e1: M-130G obtained from Shin Nakamura Chemical Industry Co., Ltd.
e2: N-hexyl-4-methylpyridinium hexafluorinated phosphorus (60% toluene solution)

(2) Preparation of Adhesive Sheet A mold release film made of a polyethylene terephthalate film that has been subjected to a mold release treatment [PLR-, a trade name obtained from Lintec Co., Ltd., is obtained from each of the adhesive compositions prepared in (1) above. 382051 ”] was applied to the release-treated surface using an applicator so that the thickness after drying was 20 μm, and dried at 100 ° C. for 1 minute to prepare an adhesive layer. The same release-treated surface side of the same release film as above was laminated on the opposite side of the release-adhesive layer to the release film to obtain an adhesive sheet. Using the obtained adhesive sheet, the peeling state was confirmed and the peeling force was measured. The results are shown in Table 3.

1 Optical laminate, 2 Polarizer, 3 1st resin film, 4 2nd resin film, 5, 6, 7, 8 Optical laminate, 10 Optical layer, 10a Single-sided protective polarizing plate, 10b Double-sided protective polarizing plate, 20 Adhesive Agent layer, 30 conductive layer, 40 substrate, 50 resin layer.

Claims (13)

1. Contains resins, cross-linking agents, and silane compounds
   The silane compound contains a Si—O—Si bond in the main chain.
   Both ends of the main chain of the silane compound have functional groups other than hydrolyzable groups.
   The side chain of the silane compound is a pressure-sensitive adhesive composition having a functional group other than a carboxyl group.
2. The pressure-sensitive adhesive composition according to claim 1, wherein the silane compound is a leveling agent.
3. The pressure-sensitive adhesive composition according to claim 1 or 2, wherein both ends of the main chain of the silane compound are independently an alkyl group, an alkyl halide group, a phenyl group, or an aralkyl group.
4. The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein both ends of the main chain of the silane compound are methyl groups.
5. The pressure-sensitive adhesive composition according to any one of claims 1 to 4, wherein the side chains of the silane compound are independently alkyl groups or aralkyl groups.
6. The pressure-sensitive adhesive composition according to any one of claims 1 to 5, wherein the silane compound has a viscosity of 300 mPa · s or more at a temperature of 25 ° C.
7. The pressure-sensitive adhesive composition according to any one of claims 1 to 6, further comprising a silane coupling agent.
8. The silane coupling agent contains a siloxane compound containing a Si—O—Si bond in the main chain and contains.
   The pressure-sensitive adhesive composition according to claim 7, wherein the siloxane compound has a hydrolyzable group in the main chain.
9. The pressure-sensitive adhesive composition according to any one of claims 1 to 8, wherein the resin contains a (meth) acrylic resin.
10. A pressure-sensitive adhesive layer using the pressure-sensitive adhesive composition according to any one of claims 1 to 9.
11. A pressure-sensitive adhesive sheet provided with a release film having the same release treatment layer on both sides of the pressure-sensitive adhesive layer according to claim 10.
    The peeling force between one surface of the pressure-sensitive adhesive layer and the release-treated layer side of the release film is defined as the first peeling force, and the other surface of the pressure-sensitive adhesive layer opposite to the one surface. An adhesive sheet in which the first peeling force and the second peeling force are different from each other when the peeling force between the release film and the release treatment layer side of the release film is taken as the second peeling force.
12. An optical laminate containing an optical layer and an adhesive layer.
    The pressure-sensitive adhesive layer is an optical laminate, which is the pressure-sensitive adhesive layer according to claim 10.
13. The optical laminate according to claim 12, wherein the optical layer includes a polarizing plate.

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