Optical laminate and image display device

Abstract

Provided is an optical laminate capable of gently increasing adhesion to a substrate due to heat and thus improving reworkability. An optical laminate according to the present invention has a resin film, a coat layer, and an adhesive layer in this order, wherein the coat layer contains carbon nanotubes, and the adhesive layer contains a (meth)acrylic resin (A), a crosslinking agent (B), a silane compound (C), and an antistatic agent (D).

Description

Optical laminate and image display device

[0001] The present invention relates to an optical laminate and an image display device.

[0002] Polarizing plates are widely used and attached to image display devices. Examples of image display devices include liquid crystal display devices and organic electroluminescence (EL) display devices. Polarizing plates are distributed as adhesive-backed polarizing plates, in which a transparent protective film is laminated on both or one side of a polarizer and an adhesive layer is formed on at least one surface, with a release film attached to the adhesive layer. Alternatively, a composite polarizing plate may be formed by laminating a retarder on a polarizing plate with a protective film attached to both or one side of the polarizer, and an adhesive layer may be formed on the retarder side. Before attachment to an image display device, the release film is peeled off from the adhesive layer on the surface of the polarizing plate, composite polarizing plate, or retarder, and the plate is attached to a substrate such as glass of the image display device via the exposed adhesive layer. An optical laminate having such an adhesive layer is disclosed, for example, in Patent Document 1.

[0003] Japanese Patent Application Publication No. 6-313807

[0004] An optical laminate having a pressure-sensitive adhesive layer is required to be easily peelable from the substrate of an image display device as needed, i.e., to have good reworkability. However, in conventional optical laminates, the adhesive strength of the pressure-sensitive adhesive layer to the substrate is likely to increase in a short period of time (for example, within 24 hours) due to heat, and the reworkability is not necessarily sufficient.

[0005] Therefore, an object of the present invention is to provide an optical laminate that can moderate the increase in adhesion to a substrate due to heat and improve reworkability, and an image display device using the same.

[0006] In order to solve the above problems, the present invention provides the following optical laminate and image display device. [1] An optical laminate having a resin film, a coating layer, and a pressure-sensitive adhesive layer in this order, wherein the coating layer contains carbon nanotubes, and the pressure-sensitive adhesive layer contains a (meth)acrylic resin (A), a crosslinking agent (B), a silane compound (C), and an antistatic agent (D). [2] The optical laminate according to [1] above, wherein the antistatic agent (D) is an ionic compound composed of a nitrogen-containing organic cation and an anion. [3] The optical laminate according to [2] above, wherein the nitrogen-containing organic cation is a cation represented by the following formula (I):

[0007] [In formula (I), R ５ , R ６ , R ７ and R ８ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkenyl group, an optionally substituted alkynyl group, an optionally substituted aryl group, or an optionally substituted heterocyclic group; R ５ , R ６ , R ７ and R ８ may form a ring with adjacent substituents.] [4] The optical laminate according to the above [2] or [3], wherein the anion is a fluorine atom-containing anion. [5] The optical laminate according to the above [4], wherein the fluorine atom-containing anion is an anion represented by the following formula (II): [Y(SO ２ C ｑ F ２ｑ＋１ ) ｐ ] －(II) [In formula (II), Y represents a carbon atom or a nitrogen atom, and when Y is a carbon atom, p is 3, and when Y is a nitrogen atom, p is 2, and q represents an integer of 0 to 10.] [6] The optical laminate according to the above [2] or [3], wherein the anion is at least one selected from the group consisting of a p-toluenesulfonate anion, a dimethylphosphinate anion, a thiocyanate anion, a carbonate anion, a tetraarylborate anion, and a dicyanamide anion. [7] The optical laminate according to any one of the above [1] to [6], which has a hard coat layer between the resin film and the coating layer. [8] The optical laminate according to any one of the above [1] to [7], which has a polarizer on the side of the resin film opposite to the coating layer. [9] The optical laminate according to the above [8], which has a second resin film on the side of the polarizer opposite to the resin film.

[10] An image display device comprising the optical laminate according to any one of the above [1] to [9].

[0008] According to the present invention, it is possible to provide an optical laminate that can moderate the increase in adhesion to a substrate due to heat and improve reworkability, and an image display device using the same.

[0009] 1 is a schematic cross-sectional view showing an example of an optical laminate according to the present invention. 2 is a GPC chromatogram showing the high molecular weight region and the low molecular weight region of a (meth)acrylic resin (A).

[0010]

[0013] Hereinafter, an embodiment of the present invention will be described in detail, with reference to the drawings as needed. [Optical Laminate] The optical laminate of the present invention has a resin film, a coating layer, and a pressure-sensitive adhesive layer, in this order. The coating layer contains carbon nanotubes, and the pressure-sensitive adhesive layer contains a (meth)acrylic resin (A), a crosslinking agent (B), a silane compound (C), and an antistatic agent (D). According to the optical laminate, since the coating layer contains carbon nanotubes and the pressure-sensitive adhesive layer contains the specific components, the increase in adhesion to the substrate due to heat can be moderated and reworkability can be improved. Although the reason for this effect is not necessarily clear, the inventors speculate that the inclusion of carbon nanotubes in the coating layer makes it easier for the antistatic agent in the pressure-sensitive adhesive layer to segregate to the surface of the pressure-sensitive adhesive layer opposite the coating layer, and the presence of this segregated antistatic agent can moderate the increase in adhesion between the laminated substrate and the pressure-sensitive adhesive layer due to heat.

[0011] FIG. 1 shows a schematic cross-sectional view of an optical laminate according to one embodiment of the present invention. The optical laminate 100 shown in FIG. 1 includes, in this order, a pressure-sensitive adhesive layer 1, a coating layer 2, a hard coating layer 3, a first resin film 4, a retardation layer 5, a first bonding layer 6, a polarizer 7, a second bonding layer 8, and a second resin film 9. The polarizer 7 is protected by a first protective layer 10 made of the hard coating layer 3, the first resin film 4, and the retardation layer 5, which is bonded to one side of the polarizer 7 via the first bonding layer 6, and a second protective layer made of the second resin film 9, which is bonded to the side of the polarizer 7 opposite the first protective layer 10 via the second bonding layer 8. The polarizer 7, the first and second bonding layers 6 and 8, and the first and second protective layers 10 and 9 form a polarizing plate 20. A separate film may be provided on the side of the pressure-sensitive adhesive layer 1 opposite the coating layer 2. Each layer constituting the optical laminate 100 will be described below.

[0012] <Pressure-sensitive adhesive layer 1> The pressure-sensitive adhesive layer contains a (meth)acrylic resin (A), a crosslinking agent (B), a silane compound (C), and an antistatic agent (D). The pressure-sensitive adhesive layer can be formed using a pressure-sensitive adhesive composition containing the above components. Each component constituting the pressure-sensitive adhesive layer will be described below.

[0013] (1) (Meth)acrylic Resin (A) The (meth)acrylic resin (A) may contain a structural unit derived from an alkyl(meth)acrylate (a) (hereinafter also referred to as "alkyl(meth)acrylate (a)") having a homopolymer glass transition temperature (hereinafter also referred to as "Tg") of less than 0°C, a structural unit derived from an alkyl(meth)acrylate (b) (hereinafter also referred to as "alkyl(meth)acrylate (b)") having a homopolymer glass transition temperature of 0°C or higher, and a structural unit derived from a monomer (c) having a polar group. In this specification, (meth)acrylic means either acrylic or methacrylic. (Meth)acrylate means either acrylate or methacrylate.

[0014] The Tg of the homopolymer of alkyl (meth)acrylate (a) and (b) can be found in literature values ​​such as POLYMER HANDBOOK (Wiley-Interscience).

[0015] Specific examples of the alkyl (meth)acrylate (a) include linear or branched alkyl acrylates having an alkyl group carbon number of 2 to 12, such as ethyl acrylate, n- and i-propyl acrylate, n- and i-butyl acrylate, n-pentyl acrylate, n- and i-hexyl acrylate, n-heptyl acrylate, n- and i-octyl acrylate, 2-ethylhexyl acrylate, n- and i-nonyl acrylate, n- and i-decyl acrylate, and n-dodecyl acrylate; and linear or branched alkyl methacrylates having an alkyl group carbon number of 4 to 12, such as n-pentyl methacrylate, n- and i-hexyl methacrylate, n-heptyl methacrylate, n- and i-octyl methacrylate, 2-ethylhexyl methacrylate, n- and i-nonyl methacrylate, n-decyl methacrylate, and n-dodecyl methacrylate. The alkyl(meth)acrylate (a) may be an alkyl(meth)acrylate having an alicyclic structure (cycloalkyl(meth)acrylate), but from the viewpoint of conformability to the optical film (or flexibility or adhesiveness), it is preferably an alkyl acrylate having 2 to 10 carbon atoms, more preferably an alkyl acrylate having 3 to 8 carbon atoms, and even more preferably an alkyl acrylate having 4 to 6 carbon atoms. Only one type of alkyl(meth)acrylate (a) may be used alone, or two or more types may be used in combination.

[0016] From the viewpoint of mechanical strength and heat resistance durability, the content of the structural units derived from the alkyl (meth)acrylate (a) is preferably 40 parts by mass or more and 90 parts by mass or less, more preferably 45 parts by mass or more and 80 parts by mass or less, and even more preferably 50 parts by mass or more and 75 parts by mass or less, relative to 100 parts by mass of all structural units constituting the (meth)acrylic resin (A).

[0017] Specific examples of the alkyl(meth)acrylate (b) include methyl acrylate, methyl methacrylate, stearyl acrylate, tert-butyl acrylate, ethyl methacrylate, isobutyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, propyl methacrylate, and isopropyl methacrylate. The alkyl(meth)acrylate (b) may be an alkyl(meth)acrylate having an alicyclic structure (cycloalkyl(meth)acrylate). The alicyclic structure may be a cycloparaffin structure having typically 5 or more carbon atoms, preferably about 5 to 7 carbon atoms. Specific examples of alkyl (meth)acrylates having an alicyclic structure include isobornyl methacrylate, cyclohexyl methacrylate, dicyclopentanyl methacrylate, trimethylcyclohexyl methacrylate, tert-butylcyclohexyl methacrylate, 1-adamantyl methacrylate, isobornyl acrylate, cyclohexyl acrylate, dicyclopentanyl acrylate, cyclododecyl acrylate, methylcyclohexyl acrylate, trimethylcyclohexyl acrylate, tert-butylcyclohexyl acrylate, and α-ethoxycyclohexyl acrylate. The alkyl (meth)acrylate (b) may be used alone or in combination of two or more. From the viewpoint of adjusting the glass transition temperatures of the low molecular weight region component and the high molecular weight region component described below, it is preferable to use an alkyl methacrylate and an alkyl acrylate in combination as the alkyl (meth)acrylate (b).

[0018] From the viewpoint of mechanical strength and heat resistance durability, the content of the structural units derived from the alkyl (meth)acrylate (b) is preferably 1 part by mass or more and 40 parts by mass or less, more preferably 3 parts by mass or more and 30 parts by mass or less, and even more preferably 5 parts by mass or more and 20 parts by mass or less, relative to 100 parts by mass of all structural units constituting the (meth)acrylic resin (A).

[0019] The alkyl(meth)acrylate (a) and the alkyl(meth)acrylate (b) may be alkyl(meth)acrylates in which a substituent has been introduced into the alkyl group in the alkyl(meth)acrylate (i.e., a hydrogen atom of the alkyl group has been substituted with a substituent). The substituent may be, for example, an aryl group (e.g., a phenyl group), an aryloxy group (e.g., a phenoxy group), or an alkoxy group (e.g., a methoxy group, an ethoxy group), etc.

[0020] The polar group-containing monomer (c) can be an ethylenically unsaturated monomer having one or more polar groups in the molecular chain. Examples of the polar group-containing monomer (c) include a monomer having a hydroxy group, a monomer having a carboxy group, and a monomer having a nitrogen atom. The polar group-containing monomer (c) may be used alone or in combination of two or more.

[0021] From the viewpoint of mechanical strength and heat resistance durability, the content of the structural unit derived from the monomer (c) having a polar group is preferably 0.1 parts by mass or more and 10 parts by mass or less, more preferably 0.3 parts by mass or more and 5 parts by mass or less, and even more preferably 0.5 parts by mass or more and 3 parts by mass or less, relative to 100 parts by mass of all structural units constituting the (meth)acrylic resin (A).

[0022] Examples of the monomer having a hydroxy group include those represented by the following formula (1):

[0023] [In formula (1), n ​​represents an integer of 1 to 5, and A １ represents a hydrogen atom or an alkyl group; X １ represents a methylene group which may have a substituent, and when n is 2 or more, the substituents may be the same or different.

[0024] In formula (1), A １ Examples of the alkyl group that can constitute the above include alkyl groups having 1 to 10 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, s-butyl, tert-butyl, pentyl, and hexyl groups. Of these, a methyl group is preferred.

[0025] In formula (1), X １ Examples of the substituent that the methylene group that can constitute the above may have include halogen atoms (fluorine atoms, chlorine atoms, bromine atoms, iodine atoms), alkyl groups (e.g., alkyl groups having 1 to 10 carbon atoms such as methyl groups, ethyl groups, propyl groups, isopropyl groups, butyl groups, s-butyl groups, tert-butyl groups, pentyl groups, hexyl groups, etc., preferably alkyl groups having 1 to 6 carbon atoms, more preferably alkyl groups having 1 to 3 carbon atoms), cycloalkyl groups (cyclopentyl groups, cyclohexyl groups, etc.), aryl groups (phenyl groups, alkylphenyl groups (tolyl groups, xylyl groups, etc.)), aralkyl groups (benzyl groups, etc.), alkoxy groups (e.g., methoxy groups, ethoxy groups, etc.), Examples of the alkyl group include an alkoxy group having 1 to 4 carbon atoms, a polyoxyalkylene group (e.g., a dioxyethylene group), a cycloalkoxy group (e.g., a cycloalkyloxy group having 5 to 10 carbon atoms, such as a cyclohexyloxy group), an aryloxy group (e.g., a phenoxy group), an aralkyloxy group (e.g., a benzyloxy group), an alkylthio group (e.g., an alkylthio group having 1 to 4 carbon atoms, such as a methylthio group or an ethylthio group), a cycloalkylthio group (e.g., a cyclohexylthio group), an arylthio group (e.g., a thiophenoxy group), an aralkylthio group (e.g., a benzylthio group), an acyl group (e.g., an acetyl group), a nitro group, and a cyano group. Among these, a halogen atom, an alkyl group, an alkoxy group, an aryloxy group, and the like are preferred, and an alkyl group (e.g., a methyl group, an ethyl group, and the like) is particularly preferred.

[0026] In formula (1), n ​​may be, for example, an integer of 1 to 4, preferably an integer of 1 to 3, and more preferably 2.

[0027] Specific examples of the hydroxy group-containing (meth)acrylate include 1-hydroxy C1 to C8 alkyl (meth)acrylates such as 1-hydroxymethyl (meth)acrylate, 1-hydroxyethyl (meth)acrylate, 1-hydroxyheptyl (meth)acrylate, 1-hydroxybutyl (meth)acrylate, and 1-hydroxypentyl (meth)acrylate; 2-hydroxy C2 to C9 alkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxypentyl (meth)acrylate, and 2-hydroxyhexyl (meth)acrylate; 3-hydroxypropyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 3-hydroxy C3 to C10 alkyl (meth)acrylates such as 4-hydroxybutyl (meth)acrylate, 4-hydroxypentyl (meth)acrylate, 4-hydroxyhexyl (meth)acrylate, 4-hydroxyheptyl (meth)acrylate; 4-hydroxy C4 to C11 alkyl (meth)acrylates such as 4-hydroxybutyl (meth)acrylate, 4-hydroxypentyl (meth)acrylate, 4-hydroxyhexyl (meth)acrylate, 4-hydroxyheptyl (meth)acrylate, 4-hydroxyoctyl (meth)acrylate; 2-chloro-2-hydroxypropyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, and the like. Of these, from the viewpoints of mechanical strength and heat resistance and durability, preferred are hydroxy group-containing (meth)acrylates in which n is 2, such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate; and hydroxy group-containing (meth)acrylates in which n is 3, such as 3-hydroxypropyl (meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 3-hydroxypentyl (meth)acrylate. In particular, preferred are hydroxy group-containing (meth)acrylates in which n is 2, and of these, preferred is 2-hydroxyethyl (meth)acrylate. One type of hydroxy group-containing (meth)acrylate may be used alone, or two or more types may be used in combination.

[0028] When the (meth)acrylic resin (A) contains a structural unit derived from a hydroxy group-containing (meth)acrylate, the content of the structural unit derived from a hydroxy group-containing (meth)acrylate is preferably 0.3 parts by mass or more and 5.5 parts by mass or less, more preferably 0.3 parts by mass or more and 4 parts by mass or less, even more preferably 0.4 parts by mass or more and 3 parts by mass or less, and particularly preferably 0.5 parts by mass or more and 2.5 parts by mass or less, relative to 100 parts by mass of all structural units constituting the (meth)acrylic resin (A), from the viewpoint of mechanical strength and heat resistance durability.

[0029] Specific examples of monomers having a carboxy group (hereinafter also referred to as "carboxy group-containing monomers") include (meth)acrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, and carboxyalkyl (meth)acrylates (e.g., carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate). Among these, acrylic acid is preferred. One type of monomer having a carboxy group may be used alone, or two or more types may be used in combination.

[0030] When the (meth)acrylic resin (A) contains a structural unit derived from a monomer having a carboxy group, the content of the structural unit derived from the carboxy group-containing monomer may be 0.05 parts by mass or more and 5.5 parts by mass or less, relative to 100 parts by mass of all structural units constituting the (meth)acrylic resin (A). From the viewpoint of mechanical strength and heat resistance durability, the content is preferably 0.05 parts by mass or more and 3 parts by mass or less, and more preferably 0.1 parts by mass or more and 2 parts by mass or less.

[0031] From the viewpoint of mechanical strength and heat resistance durability, the mass ratio of the structural units derived from the monomer having a carboxy group to the structural units derived from the hydroxy group-containing (meth)acrylate is preferably 0.06 or more and 1.0 or less, more preferably 0.06 or more and 0.9 or less, even more preferably 0.08 or more and 0.8 or less, and particularly preferably 0.1 or more and 0.7 or less.

[0032] Examples of the nitrogen atom-containing monomer include amino group-containing monomers, amide group-containing monomers, other nitrogen atom-containing monomers, etc. The nitrogen atom-containing monomers may be used alone or in combination of two or more.

[0033] Examples of amino group-containing monomers include primary amino group-containing monomers such as aminomethyl (meth)acrylate and aminoethyl (meth)acrylate; secondary amino group-containing monomers such as t-butylaminoethyl (meth)acrylate; and tertiary amino group-containing monomers such as ethylaminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, and diethylaminoethyl (meth)acrylate. From the viewpoint of preventing a decrease in the releasability of a separate film that can be laminated to the pressure-sensitive adhesive layer, it is preferable that the resin is substantially free of structural units derived from monomers having amino groups. "Substantially free" means that the amount is less than 1.0 part by mass relative to 100 parts by mass of all structural units constituting the (meth)acrylic resin (A).

[0034] Examples of the amide group-containing monomer include (meth)acrylamide; alkoxyalkyl (meth)acrylamide-based monomers such as methoxymethyl (meth)acrylamide, ethoxymethyl (meth)acrylamide, propoxymethyl (meth)acrylamide, isopropoxymethyl (meth)acrylamide, n-butoxymethyl (meth)acrylamide, and isobutoxymethyl (meth)acrylamide; hydroxyl group-containing amide monomers such as N-(hydroxymethyl)acrylamide; dialkyl (meth)acrylamide-based monomers such as dimethyl (meth)acrylamide and diethyl (meth)acrylamide; and heterocyclic amide monomers such as (meth)acryloylmorpholine.

[0035] More specifically, for example, N-methylol(meth)acrylamide, N-(2-hydroxyethyl)(meth)acrylamide, N-(3-hydroxypropyl)(meth)acrylamide, N-(4-hydroxybutyl)(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, Acrylamide, N-(3-dimethylaminopropyl)(meth)acrylamide, N-(1,1-dimethyl-3-oxobutyl)(meth)acrylamide, N-[2-(2-oxo-1-imidazolidinyl)ethyl](meth)acrylamide, 2-(meth)acryloylamino-2-methyl-1-propanesulfonic acid, N-(methoxymethyl)(meth)acrylamide, N-(ethoxymethyl)(meth)acrylamide, N-(propoxymethyl)(meth)acrylamide, N-(1-methyl N-(1-methylpropoxymethyl)(meth)acrylamide, N-(2-methylpropoxymethyl)(meth)acrylamide [alias: N-(isobutoxymethyl)(meth)acrylamide], N-(butoxymethyl)(meth)acrylamide, N-(1,1-dimethylethoxymethyl)(meth)acrylamide, N-(2-methoxyethyl)(meth)acrylamide, N-(2-ethoxyethyl)(meth)acrylamide, N-(2

[0033] Examples of the methacrylamide include 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)acrylamide), N-(2-butoxyethyl)(meth)acrylamide, and N-[2-(1,1-dimethylethoxy)ethyl](meth)acrylamide.

[0036] The (meth)acrylic resin (A) may further contain a structural unit derived from a styrene-based monomer, a structural unit derived from a vinyl-based monomer, a structural unit derived from a monomer having multiple (meth)acryloyl groups in the molecule, or the like.

[0037] Examples of styrene-based monomers include styrene; alkyl styrenes such as methylstyrene, dimethylstyrene, trimethylstyrene, ethylstyrene, diethylstyrene, triethylstyrene, propylstyrene, butylstyrene, hexylstyrene, heptylstyrene, and octylstyrene; halogenated styrenes such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, and iodostyrene; nitrostyrene; acetylstyrene; methoxystyrene; and divinylbenzene.

[0038] Examples of vinyl monomers include fatty acid vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, and vinyl laurate; vinyl halides such as vinyl chloride and vinyl bromide; vinylidene halides such as vinylidene chloride; nitrogen-containing aromatic vinyls such as vinylpyridine, vinylpyrrolidone, and vinylcarbazole; and conjugated diene monomers such as butadiene, isoprene, and chloroprene.

[0039] Examples of the monomer having multiple (meth)acryloyl groups in the molecule include monomers having two (meth)acryloyl groups in the molecule, such as 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and tripropylene glycol di(meth)acrylate; and monomers having three (meth)acryloyl groups in the molecule, such as trimethylolpropane tri(meth)acrylate.

[0040] The weight average molecular weight (Mw) of the (meth)acrylic resin (A) is preferably 1,000,000 or more and 2,000,000 or less, more preferably 1,100,000 to 1,900,000, even more preferably 1,200,000 to 1,800,000, and particularly preferably 1,300,000 to 1,700,000, from the viewpoint of mechanical strength and heat resistance durability. Furthermore, the molecular weight distribution (Mw / Mn), expressed as the ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the (meth)acrylic resin (A), may be, for example, 1.5 or more and 10 or less, and is preferably less than 3.5, more preferably 2.5 or more and less than 3.5, from the viewpoint of mechanical strength and heat resistance durability. The weight average molecular weight can be analyzed by gel permeation chromatography (GPC) and is a value converted into standard polystyrene.

[0041] The (meth)acrylic resin (A) may contain a resin component contained in a high molecular weight region (hereinafter referred to as a "high molecular weight region component") and a resin component contained in a low molecular weight region (hereinafter referred to as a "low molecular weight region component"). As shown in FIG. 2, the high molecular weight region component is a resin component that is contained in a 10% area region on the high molecular weight side of the peak area derived from the (meth)acrylic resin (A) in a chromatogram obtained by GPC measurement (region (1) in FIG. 2). As shown in FIG. 2, the low molecular weight region component is a component that is contained in a 10% area region on the low molecular weight side of the peak area derived from the (meth)acrylic resin (A) in a chromatogram obtained by GPC measurement (region (2) in FIG. 2). GPC measurement is performed according to the method described in the Examples section below.

[0042] The glass transition temperature of the high molecular weight region component may be higher than that of the low molecular weight region component. When the glass transition temperature of the high molecular weight region component is higher than that of the low molecular weight region component, mechanical strength and heat resistance durability tend to be improved. The glass transition temperatures of the high molecular weight region component and the low molecular weight region component can be adjusted, for example, by selecting the raw materials used in the production of the (meth)acrylic resin (A), adjusting the amounts charged, the order of charging, and production conditions (e.g., temperature, time, nitrogen concentration in the system, etc.).

[0043] The glass transition temperature of the high molecular weight region component is preferably −30° C. or higher, more preferably −28° C. or higher, and even more preferably −26° C. or higher, from the viewpoint of mechanical strength and heat resistance durability.

[0044] The glass transition temperature of the low molecular weight region component may be, for example, less than −30° C., and from the viewpoint of mechanical strength and heat resistance durability, is preferably −34° C. or lower, more preferably −36° C. or lower.

[0045] The difference (absolute value) between the glass transition temperature of the high molecular weight region component and the glass transition temperature of the low molecular weight region component is preferably 10°C or more, more preferably 11°C or more, from the viewpoint of mechanical strength and heat resistance durability.

[0046] The glass transition temperature (Tg) of the (meth)acrylic resin (A) is preferably −45° C. or higher and −10° C. or lower, more preferably −40° C. or higher and −15° C. or lower, and even more preferably −38° C. or higher and −20° C. or lower, from the viewpoint of mechanical strength and heat resistance durability.

[0047] The (meth)acrylic resin (A) (or a mixture thereof when two or more types are combined) preferably has a viscosity of 20 Pa s or less, and more preferably 0.1 Pa s or more and 7 Pa s or less, at 25° C. when dissolved in ethyl acetate to a concentration of 20 mass %. The viscosity can be measured using a Brookfield viscometer.

[0048] The (meth)acrylic resin (A) can be produced by known methods such as solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization. A polymerization initiator is usually used in the production of the (meth)acrylic resin (A). The polymerization initiator is used in an amount of about 0.001 to 5 parts by mass per 100 parts by mass of the total of all monomers used in the production of the (meth)acrylic resin (A). The (meth)acrylic resin (A) may also be produced by a method in which polymerization is promoted by active energy rays such as ultraviolet light.

[0049] As the polymerization initiator, a thermal polymerization initiator or a photopolymerization initiator is used. Examples of the photopolymerization initiator include 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone. Examples of the thermal polymerization initiator include azo compounds such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), dimethyl-2,2'-azobis(2-methylpropionate), and 2,2'-azobis(2-hydroxymethylpropionitrile); lauryl peroxide. Examples of the peroxide include organic peroxides such as tert-butyl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, tert-butyl peroxybenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, dipropyl peroxydicarbonate, tert-butyl peroxyneodecanoate, tert-butyl peroxypivalate, and (3,5,5-trimethylhexanoyl)peroxide; and inorganic peroxides such as potassium persulfate, ammonium persulfate, and hydrogen peroxide. Furthermore, redox initiators using a peroxide in combination with a reducing agent can also be used as the polymerization initiator.

[0050] Among the methods listed above, solution polymerization is preferred as a method for producing the (meth)acrylic resin (A). One example of the solution polymerization method involves mixing the monomer and an organic solvent, adding a thermal polymerization initiator under a nitrogen atmosphere, and stirring for 3 to 48 hours at approximately 40 to 90°C, preferably approximately 50 to 80°C. To control the reaction, the monomer and the thermal polymerization initiator may be added continuously or intermittently during polymerization, or may be added in a dissolved state in an organic solvent. Examples of organic solvents that can be used include aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; aliphatic alcohols such as propyl alcohol and isopropyl alcohol; and ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone.

[0051] (2) Crosslinking Agent (B) The pressure-sensitive adhesive composition further contains a crosslinking agent (B). The crosslinking agent (B) can be a compound that reacts with structural units derived from polar functional group-containing monomers in the (meth)acrylic resin (A) to crosslink the (meth)acrylic resin (A). Specific examples include isocyanate-based compounds, epoxy-based compounds, aziridine-based compounds, and metal chelate-based compounds. Of these, isocyanate-based compounds, epoxy-based compounds, and aziridine-based compounds are preferably compounds having at least two functional groups in the molecule that can react with the polar functional groups in the (meth)acrylic resin. The crosslinking agent (B) may be used alone or in combination of two or more types.

[0052] The isocyanate compound is preferably a compound having at least two isocyanato groups (-NCO) in the molecule, and examples thereof include aliphatic isocyanate compounds (e.g., hexamethylene diisocyanate, etc.), alicyclic isocyanate compounds (e.g., isophorone diisocyanate), and aromatic isocyanate compounds (e.g., tolylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, etc.). The crosslinking agent (B) may also be an adduct of an isocyanate compound with a polyhydric alcohol compound (e.g., an adduct with glycerol, trimethylolpropane, etc.), an isocyanurate, a biuret-type compound, or a derivative of a urethane prepolymer-type isocyanate compound obtained by addition reaction with a polyether polyol, a polyester polyol, an acrylic polyol, a polybutadiene polyol, a polyisoprene polyol, etc. The crosslinking agent (B) may be used alone or in combination of two or more. Representative examples of these include aromatic isocyanate compounds (e.g., tolylene diisocyanate, xylylene diisocyanate), aliphatic isocyanate compounds (e.g., hexamethylene diisocyanate), or adducts thereof with polyhydric alcohol compounds (glycerol, trimethylolpropane). When the crosslinking agent (B) contains an aromatic isocyanate compound and / or an adduct thereof with a polyhydric alcohol compound, mechanical strength and heat resistance durability tend to be improved.

[0053] The epoxy compound is preferably a compound having at least two epoxy groups in the molecule. Specific examples of the compound include bisphenol A epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, N,N-diglycidylaniline, N,N,N',N'-tetraglycidyl-m-xylylenediamine, and 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane. Two or more epoxy compounds can also be used in combination.

[0054] The aziridine compound is preferably a compound having at least two three-membered ring skeletons, each consisting of one nitrogen atom and two carbon atoms, also known as ethyleneimine, within the molecule. Specific examples of such compounds include diphenylmethane-4,4'-bis(1-aziridinecarboxamide), toluene-2,4-bis(1-aziridinecarboxamide), triethylenemelamine, isophthaloylbis-1-(2-methylaziridine), tris-1-aziridinylphosphine oxide, hexamethylene-1,6-bis(1-aziridinecarboxamide), trimethylolpropane-tris-β-aziridinylpropionate, and tetramethylolmethane-tris-β-aziridinylpropionate.

[0055] Examples of metal chelate compounds include compounds in which acetylacetone or ethyl acetoacetate is coordinated with a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, or zirconium.

[0056] Among these, isocyanate compounds are preferred, and aromatic isocyanate compounds such as tolylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate, and adducts thereof with polyhydric alcohol compounds (for example, glycerol, trimethylolpropane, etc.) are more preferred.

[0057] The content of the crosslinking agent (B) is preferably 0.2 parts by mass or more and 5.0 parts by mass or less, more preferably 0.5 parts by mass or more and 2.0 parts by mass or less, relative to 100 parts by mass of the solid content of the (meth)acrylic resin (A) (when two or more types are used, the total amount of the crosslinking agent (B) and the (meth)acrylic resin (A)) from the viewpoint of mechanical strength and heat resistance durability.

[0058] (3) Silane Compound (C) The pressure-sensitive adhesive composition contains a silane compound (C). By including the silane compound (C), it is possible to improve the adhesion (or adhesiveness) between the pressure-sensitive adhesive layer and a metal layer, a transparent electrode, a glass substrate, etc. Examples of the silane compound (C) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylethoxydimethylsilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 1,3-bis(3'-trimethoxypropyl)urea, 1,6-bis(trimethoxysilyl)hexane, and 1,8-bis(trimethoxysilyl)octane.

[0059] The silane compound may be a silicone oligomer. Specific examples of silicone oligomers are shown below. In the following specific examples, the silicone oligomers are expressed in the form of a combination of monomers.

[0060] Mercaptopropyl group-containing oligomers such as 3-mercaptopropyltrimethoxysilane-tetramethoxysilane oligomer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane oligomer, 3-mercaptopropyltriethoxysilane-tetramethoxysilane oligomer, and 3-mercaptopropyltriethoxysilane-tetraethoxysilane oligomer.

[0061] Mercaptomethyl group-containing oligomers such as mercaptomethyltrimethoxysilane-tetramethoxysilane oligomer, mercaptomethyltrimethoxysilane-tetraethoxysilane oligomer, mercaptomethyltriethoxysilane-tetramethoxysilane oligomer, and mercaptomethyltriethoxysilane-tetraethoxysilane oligomer.

[0062] Methacryloyloxypropyl group-containing oligomers such as 3-methacryloyloxypropyltrimethoxysilane-tetramethoxysilane oligomer, 3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane oligomer, 3-methacryloyloxypropyltriethoxysilane-tetramethoxysilane oligomer, 3-methacryloyloxypropyltriethoxysilane-tetraethoxysilane oligomer, 3-methacryloyloxypropylmethyldimethoxysilane-tetramethoxysilane oligomer, 3-methacryloyloxypropylmethyldimethoxysilane-tetraethoxysilane oligomer, 3-methacryloyloxypropylmethyldiethoxysilane-tetramethoxysilane oligomer, and 3-methacryloyloxypropylmethyldiethoxysilane-tetraethoxysilane oligomer.

[0063] Acryloyloxypropyl group-containing oligomers such as 3-acryloyloxypropyltrimethoxysilane-tetramethoxysilane oligomer, 3-acryloyloxypropyltrimethoxysilane-tetraethoxysilane oligomer, 3-acryloyloxypropyltriethoxysilane-tetramethoxysilane oligomer, 3-acryloyloxypropyltriethoxysilane-tetraethoxysilane oligomer, 3-acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane oligomer, 3-acryloyloxypropylmethyldimethoxysilane-tetraethoxysilane oligomer, 3-acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane oligomer, and 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane oligomer.

[0064] Vinyl group-containing oligomers such as vinyltrimethoxysilane-tetramethoxysilane oligomer, vinyltrimethoxysilane-tetraethoxysilane oligomer, vinyltriethoxysilane-tetramethoxysilane oligomer, vinyltriethoxysilane-tetraethoxysilane oligomer, vinylmethyldimethoxysilane-tetramethoxysilane oligomer, vinylmethyldimethoxysilane-tetraethoxysilane oligomer, vinylmethyldiethoxysilane-tetramethoxysilane oligomer, and vinylmethyldiethoxysilane-tetraethoxysilane oligomer.

[0065] The silane compound (C) is represented by the following formula (C):

[0066] By including the silane compound (C), adhesion to metals, transparent electrodes, glass substrates, etc. in high-temperature environments tends to be improved, and heat resistance and durability tend to be excellent. １ , R ２ and R ３are each independently an alkyl group having 1 to 3 carbon atoms or an alkoxy group having 1 to 3 carbon atoms. Examples of the alkyl group having 1 to 3 carbon atoms include a methyl group, an ethyl group, an n-propyl group, and an i-propyl group, and examples of the alkoxy group having 1 to 3 carbon atoms include a methoxy group, an ethoxy group, an n-propoxy group, and an i-propoxy group.

[0067] In formula (C), L represents an alkylene group having 8 to 12 carbon atoms, or a group in which at least one methylene group constituting the alkylene group is substituted with a group selected from the group consisting of -NH- and O-. Examples of the alkylene group having 8 to 12 carbon atoms include -(CH ２ ) ８ -, -(CH ２ ) ９ -, -(CH ２ ) １０ -, -(CH ２ ) １１ -, -(CH ２ ) １２ - is an example.

[0068] When L is a group in which at least one methylene group constituting an alkylene group having 8 to 12 carbon atoms is substituted with a group selected from the group consisting of -NH- and O-, only one methylene group may be substituted with -NH- or O-, or two or more methylene groups may each be substituted with -NH- or O-. When two or more methylene groups are substituted, typically, the two or more substituted -NH- and / or O- are bonded via an alkylene group having two or more carbon atoms.

[0069] In formula (C), X represents a thiol group (—SH), a group represented by the following formula:

[0070] an epoxy group represented by the formula (—NH ２ ), or an alicyclic epoxy group.

[0071] The alicyclic epoxy group includes the following formula:

[0072] (wherein a represents an integer of 1 to 5).

[0073] Among them, the silane compound (C) is R １ , R ２ and R ３ are each independently a methoxy group or an ethoxy group, and X is a thiol group, an epoxy group, or an amino group, and is represented by the following formula (C-1):

[0074] In the above formula (C-1), m represents an integer of 6 to 10.

[0075] Specific examples of the silane compound (C-1) include 6-glycidoxyhexyltrimethoxysilane, 7-glycidoxyheptyltrimethoxysilane, 8-glycidoxyoctyltrimethoxysilane, 9-glycidoxynonyltrimethoxysilane, and 10-glycidoxydecyltrimethoxysilane. Most of the silane compounds (C-1) are liquid. As the silane compound (C-1), a commercially available product may be used, or one produced by a known method may be used.

[0076] The content of the silane compound (C) in the pressure-sensitive adhesive composition is usually 0.01 parts by mass or more and 5 parts by mass or less, relative to 100 parts by mass of the solid content of the (meth)acrylic resin (A) (when two or more types are used, the total amount of the (meth)acrylic resins (A)), and from the viewpoints of mechanical strength and heat resistance durability, it is preferably 0.1 parts by mass or more and 4 parts by mass or less, and more preferably 0.2 parts by mass or more and 3 parts by mass or less.

[0077] (4) Antistatic Agent (D) The PSA composition further contains an antistatic agent (D). By including the antistatic agent (D) in the PSA layer, it is possible to impart antistatic properties to the PSA layer.

[0078] From the viewpoint of further improving the antistatic properties and reworkability, the antistatic agent (D) may be an ionic compound having an inorganic cation or an organic cation and an anion, or may be an ionic compound having an organic cation and an anion.

[0079] Examples of organic cations constituting the ionic compound include imidazolium cations, pyridinium cations, pyrrolidinium cations, ammonium cations, sulfonium cations, phosphonium cations, etc. Specific examples of organic cations include ammonium cations such as tributylmethylammonium cation, trioctylmethylammonium cation, trimethylpropylammonium cation, tetrabutylammonium cation, and (2-hydroxyethyl)trimethylammonium cation; phosphonium cations such as tributyldodecylphosphonium cation; pyridinium cations such as 1-hexylpyridinium cation, 1-octylpyridinium cation, 4-methyl-1-hexylpyridinium cation, 4-methyl-1-octylpyridinium cation, and 4-methyl-1-butylpyridinium cation; pyrrolidinium cations such as butylmethylpyrrolidinium cation and ethylmethylpyrrolidinium cation; and imidazolium cations such as 1-ethyl-3-methylimidazolium cation and 1-butyl-3-methylimidazolium cation.

[0080] As the organic cation, from the viewpoint of further improving antistatic properties and reworkability, a nitrogen atom-containing organic cation containing a nitrogen atom is preferred, a cation represented by the following formula (I) is more preferred, an ammonium cation, an imidazolium cation, or a pyridinium cation is even more preferred, and an ammonium cation is particularly preferred. Furthermore, as the organic cation, from the viewpoint of suppressing the refractive index fluctuation of the adhesive due to the use of an aromatic ring-containing compound, an aliphatic cation is preferred, and a pyrrolidinium cation or an ammonium cation is more preferred.

[0081] [In formula (I), R ５ , R ６ , R ７ and R ８ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkenyl group, an optionally substituted alkynyl group, an optionally substituted aryl group, or an optionally substituted heterocyclic group; R５ , R ６ , R ７ and R ８ Adjacent substituents may be joined together to form a ring.

[0082] The anion constituting the ionic compound is preferably a fluorine atom-containing anion, more preferably an anion represented by the following formula (II), from the viewpoint of further improving antistatic properties and reworkability: [Y(SO ２ C ｑ F ２ｑ＋１ ) ｐ ] － (II) [In formula (II), Y represents a carbon atom or a nitrogen atom, and when Y is a carbon atom, p is 3, and when Y is a nitrogen atom, p is 2, and q represents an integer of 0 to 10.]

[0083] Specific examples of the anion represented by the above formula (II) include bis(trifluoromethanesulfonyl)imide anion [(CF ３ SO ２ ) ２ N － ], bis(pentafluoroethanesulfonyl)imide anion [(C ２ F ５ SO ２ ) ２ N － ], bis(heptafluoropropanesulfonyl)imide anion, bis(nonafluorobutanesulfonyl)imide anion, tris(trifluoromethanesulfonyl)methanide anion [(CF ３ SO ２ ) ３ C － ] etc.

[0084] The anion constituting the ionic compound may be an anion other than the anion represented by the above formula (II), and examples thereof include trifluoromethanesulfonyl(pentafluoroethanesulfonyl)imide anion, trifluoromethanesulfonyl(heptafluoropropanesulfonyl)imide anion, trifluoromethanesulfonyl(nonafluorobutanesulfonyl)imide anion, 1,1,2,2,3,3-hexafluoropropane-1,3-disulfonimide anion, p-toluenesulfonate anion [p-CH ３ C ６ H ４ SO ３ － ], dimethylphosphinate anion [(CH ３ ) ２ P.O.O. － ], thiocyanate anion [SCN － ], carbonate anion [CO ３ ２－ ], tetraarylborate anion (e.g., tetrakis(pentafluorophenyl)borate anion, etc.), dicyanamide anion [(CN) ２ N － ] etc. may also be used.

[0085] The ionic compounds can be used alone or in combination of two or more. The PSA composition may contain, as the antistatic agent (D), an antistatic agent other than the above-mentioned ionic compounds.

[0086] The ionic compound is effective in imparting antistatic properties to the pressure-sensitive adhesive layer formed from the pressure-sensitive adhesive composition containing the (meth)acrylic resin (A) and in maintaining various physical properties of the pressure-sensitive adhesive. In particular, when an ionic compound that is solid at room temperature (25°C) is used, the antistatic performance can be maintained for a longer period of time than when an ionic compound that is liquid at room temperature is used. From the viewpoint of long-term stability of antistatic properties, it is preferable that the ionic compound has a melting point of 23°C or higher. On the other hand, if the melting point is too high, compatibility with the (meth)acrylic resin (A) will be poor, so the melting point is preferably 90°C or lower, more preferably 70°C or lower, and even more preferably lower than 50°C. The molecular weight of the ionic compound is not particularly limited, but may be, for example, 700 or lower, or even 500 or lower.

[0087] The content of the antistatic agent (D) in the pressure-sensitive adhesive composition is usually 0.2 parts by mass or more and 8 parts by mass or less, relative to 100 parts by mass of the solid content of the (meth)acrylic resin (A) (when two or more types are used, the total amount of the (meth)acrylic resins (A)), and from the viewpoint of mechanical strength and heat resistance durability, it is preferably 0.2 parts by mass or more and 5 parts by mass or less, more preferably 0.5 parts by mass or more and 4 parts by mass or less.

[0088] (5) Other Components The pressure-sensitive adhesive composition may contain additives such as a crosslinking catalyst, a weather stabilizer, a tackifier, a plasticizer, a softener, a dye, a pigment, an inorganic filler, light-scattering fine particles, a resin other than the (meth)acrylic resin (A), etc. In addition, it is also useful to blend an ultraviolet-curable compound into the pressure-sensitive adhesive composition, form a pressure-sensitive adhesive layer, and then cure the resulting composition by irradiating the composition with ultraviolet light to form a harder pressure-sensitive adhesive layer.

[0089] When the pressure-sensitive adhesive composition contains a crosslinking catalyst together with the crosslinking agent (B), the pressure-sensitive adhesive layer can be prepared by aging for a short period of time. Furthermore, the inclusion of a crosslinking catalyst can more effectively suppress lifting or peeling at the interface between the pressure-sensitive adhesive layer and the adjacent member, as well as foaming of the pressure-sensitive adhesive layer, and can also further improve mechanical strength. Examples of crosslinking catalysts include amine-based compounds such as hexamethylenediamine, ethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethylenetetramine, isophoronediamine, trimethylenediamine, polyamino resins, and melamine resins. When an amine-based compound is blended as a crosslinking catalyst in the pressure-sensitive adhesive composition, an isocyanate-based compound is preferred as the crosslinking agent (B).

[0090] The pressure-sensitive adhesive composition can be prepared by mixing the above components. The pressure-sensitive adhesive composition may have a gel fraction of, for example, 50% to 98%, preferably 60% to 95%. The gel fraction can be measured, for example, by the following method. The prepared pressure-sensitive adhesive layer (pressure-sensitive adhesive sheet) is stored at 23°C and 60% RH for 7 days. The gel fraction [gel fraction at 23°C (G23)] of the pressure-sensitive adhesive layer (pressure-sensitive adhesive sheet) after storage is measured. The gel fraction is measured according to the following [a] to [d]. [a] A pressure-sensitive adhesive layer having an area of ​​approximately 8 cm x approximately 8 cm is bonded to a metal mesh made of SUS304 having an area of ​​approximately 10 cm x approximately 10 cm (its mass is designated as Wm). [b] The bonded product obtained in [a] above is weighed, and its mass is designated as Ws. Next, the adhesive layer is folded four times to enclose the adhesive layer, stapled, and then weighed, and its mass is designated as Wb. [c] The mesh stapled in [b] above is placed in a glass container, 60 mL of ethyl acetate is added, and the glass container is then stored at room temperature for 3 days. [d] The mesh is removed from the glass container, dried at 120°C for 4 hours, and then weighed. Its mass is designated as Wa, and the gel fraction is calculated based on the following formula: Gel fraction (mass%) = [{Wa - (Wb - Ws) - Wm} / (Ws - Wm)] x 100.

[0091] The adhesive composition is prepared by dissolving or dispersing the above-mentioned components in a solvent, applying the solution or dispersion to a suitable substrate, and drying the applied solution to form an adhesive layer.

[0092] The thickness of the pressure-sensitive adhesive layer may be, for example, 10 μm or more and 50 μm or less, and is preferably 15 μm or more and 40 μm or less, more preferably 18 μm or more and 35 μm or less, from the viewpoint of mechanical strength and heat resistance durability. When the thickness of the pressure-sensitive adhesive layer is 10 μm or more, a decrease in adhesiveness can be suppressed, thereby reducing the possibility of problems occurring in durability. When the thickness is 50 μm or less, problems such as the end face of the pressure-sensitive adhesive layer adhering to the cutting blade and being removed when cutting the optical laminate can be suppressed.

[0093] <Coating layer 2> The coating layer is a layer disposed between the pressure-sensitive adhesive layer and the first resin film of the polarizing plate, and contains carbon nanotubes (hereinafter, sometimes referred to as "CNTs"). The coating layer is a layer having conductivity (conductive layer) and functions as an antistatic layer.

[0094] The coating layer can be formed, for example, by applying a coating liquid containing carbon nanotubes onto the first resin film and drying the coating liquid. The coating liquid may contain other components such as a surfactant, a binder resin, a crosslinking agent, and a solvent in addition to the carbon nanotubes.

[0095] The solvent is not particularly limited, but examples thereof include water; alcohols such as methanol, ethanol, 2-propanol, and 1-propanol; ethylene glycols such as ethylene glycol, diethylene glycol, trimethylene glycol, triethylene glycol, and tetraethylene glycol; amide compounds such as acetonitrile, N-methylformaldehyde, N,N-dimethylformamide, γ-butyrolactone, and N-methylpyrrolidone; and dimethyl sulfoxide. The solvent may be a mixed solvent of water and another solvent. When the coating liquid contains a solvent other than water, the content of the solvent other than water is preferably 70% by mass or less, and more preferably 0.1 to 50% by mass, of the coating liquid.

[0096] The crosslinking agent is preferably soluble in the above solvent, more preferably soluble in water. Examples of the crosslinking agent include melamine-based, carbodiimide-based, oxazoline-based, epoxy-based, isocyanate-based, acrylate-based, and alkoxysilane-based compounds, and more specifically, the compounds described in JP-A-2020-175610 and JP-A-2020-175611.

[0097] Examples of binder resins include epoxy resins, phenolic resins, acrylic resins, urethane resins, polyethylene glycol, polyvinyl alcohol, polyvinyl butyral, polyvinyl alcohol-polyethylene copolymers, polyvinyl acetal, polyvinyl alcohol-polyvinyl acetal copolymers, and polyvinyl alcohol-polyvinyl butyral copolymers.

[0098] Examples of surfactants include siloxane-based compounds, fluorine-based compounds, polyether-based compounds, and more specifically, compounds described in JP-A-2020-175610 and JP-A-2020-175611.

[0099] The type of carbon nanotube is not particularly limited, and any of single-walled carbon nanotubes, double-walled carbon nanotubes, multi-walled carbon nanotubes, and mixtures containing these in any ratio can be used. Single-walled carbon nanotubes are preferred because of their excellent conductivity.

[0100] Commercially available single-walled carbon nanotubes include, for example, the SWeNT series manufactured by Toray Industries, Inc., TUBALL (registered trademark) manufactured by OCSiAl Corporation, and the Denatron (registered trademark) Type-C series (CD-100, C-169PF) manufactured by Nagase ChemteX Corporation.

[0101] Commercially available multi-walled carbon nanotubes include, for example, the VGCF (registered trademark) series from Resonac Co., Ltd. and Baytubes (registered trademark) from Bayer AG.

[0102] The content of carbon nanotubes in the coating layer is usually 0.001% by mass or more and 95% by mass or less, and may be 0.005% by mass or more and 90% by mass or less, based on the total amount of the coating layer.

[0103] The thickness of the coating layer is usually 1 nm or more and 500 nm or less, and from the viewpoint of antistatic properties and transmittance, it is preferably 5 nm or more and 400 nm or less, more preferably 10 nm or more and 300 nm or less.

[0104] From the viewpoint of antistatic performance, the surface resistance of the coating layer is 1.0×10 １２ It is preferably 1.0×10 Ω / □ or less, １１ It is more preferable that the resistance is Ω / □ or less, and 1.0×10 １０ It is more preferable that the resistance is Ω / □ or less, and 1.0×10 ９ It is particularly preferable that the surface resistance of the coating layer is 1.0×10 ３ It is preferably Ω / □ or more, and 1.0×10 ４ More preferably, it is 1.0×10 ５ It is more preferable that the surface resistance is Ω / □ or more. The surface resistance of the coating layer can be measured by the method described in the examples.

[0105] <Polarizing plate 20> The polarizing plate has a structure in which a first protective layer is provided on one surface of a polarizer via a first bonding layer, and a second protective layer is provided on the other surface via a second bonding layer. The polarizing plate may be a linear polarizing plate or a composite polarizing plate including a retardation layer. The polarizing plate shown in FIG. 1 is a composite polarizing plate including a retardation layer. Each layer constituting the polarizing plate will be described below.

[0106] <Polarizer 7> The polarizer includes a linear polarization layer. The linear polarization layer has the property of transmitting linearly polarized light having a vibration plane perpendicular to the absorption axis when unpolarized light is incident on the linear polarization layer. The linear polarization layer may be a polyvinyl alcohol-based resin film (hereinafter sometimes referred to as a "PVA-based film") in which iodine is adsorbed and oriented.

[0107] Examples of the linearly polarizing layer that is a PVA-based film include a PVA-based film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, or an ethylene-vinyl acetate copolymer-based partially saponified film, which has been subjected to a dyeing treatment with iodine and a stretching treatment. If necessary, the PVA-based film that has been dyed to adsorb and align iodine may be treated with an aqueous boric acid solution, followed by a washing step in which the aqueous boric acid solution is washed away. Known methods can be used for each step.

[0108] Polyvinyl alcohol resins (hereinafter sometimes referred to as "PVA resins") can be produced by saponifying polyvinyl acetate resins. Polyvinyl acetate resins can be polyvinyl acetate, which is a homopolymer of vinyl acetate, or copolymers of vinyl acetate and other monomers copolymerizable with vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

[0109] The saponification degree of the PVA-based resin is usually about 85 to 100 mol%, preferably 98 mol% or more. The PVA-based resin may be modified; for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may also be used. The average polymerization degree of the PVA-based resin is usually about 1,000 to 10,000, preferably about 1,500 to 5,000. The saponification degree and average polymerization degree of the PVA-based resin can be determined in accordance with JIS K 6726 (1994). If the average polymerization degree is less than 1,000, it is difficult to obtain favorable polarizing performance, and if it exceeds 10,000, film processability may be poor.

[0110] The method for producing a linearly polarizing layer that is a PVA-based film may include the steps of preparing a substrate film, applying a solution of a resin such as a PVA-based resin onto the substrate film, and performing drying or the like to remove the solvent to form a resin layer on the substrate film. A primer layer may be formed in advance on the surface of the substrate film on which the resin layer is to be formed. The substrate film may be a film made of a resin material described below as a thermoplastic resin used to form a protective film as a protective layer. Examples of materials for the primer layer include resins obtained by crosslinking the hydrophilic resin used in the linearly polarizing layer.

[0111] Next, the amount of solvent, such as water, in the resin layer is adjusted as needed, and then the substrate film and resin layer are uniaxially stretched. The resin layer is then dyed with iodine to adsorb and align the iodine in the resin layer. Next, as needed, the resin layer with iodine adsorbed and aligning is treated with a boric acid solution, followed by a washing step to wash off the boric acid solution. This produces a resin layer with iodine adsorbed and aligning, i.e., a PVA-based film that will become a linearly polarizing layer. Known methods can be used for each step.

[0112] The amount of boric acid in the boric acid-containing aqueous solution used to treat the iodine-adsorbed and oriented PVA-based film or resin layer is typically about 2 to 15 parts by mass, preferably 5 to 12 parts by mass, per 100 parts by mass of water. This boric acid-containing aqueous solution preferably contains potassium iodide. The amount of potassium iodide in the boric acid-containing aqueous solution is typically about 0.1 to 15 parts by mass, preferably about 5 to 12 parts by mass, per 100 parts by mass of water. The immersion time in the boric acid-containing aqueous solution is typically about 60 to 1,200 seconds, preferably about 150 to 600 seconds, and more preferably about 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is typically 50°C or higher, preferably 50 to 85°C, and more preferably 60 to 80°C.

[0113] The uniaxial stretching of the PVA-based film, the substrate film, and the resin layer may be performed before dyeing, during dyeing, or during the boric acid treatment after dyeing. Uniaxial stretching may be performed at each of these stages. The PVA-based film, the substrate film, and the resin layer may be uniaxially stretched in the MD direction (film transport direction). In this case, uniaxial stretching may be performed between rolls with different peripheral speeds, or may be performed using a heated roll. The PVA-based film, the substrate film, and the resin layer may be uniaxially stretched in the TD direction (direction perpendicular to the film transport direction). In this case, a so-called tenter method may be used. The stretching may be dry stretching in which stretching is performed in the air, or wet stretching in which stretching is performed after swelling the PVA-based film or the resin layer with a solvent. To exhibit the performance of the linearly polarizing layer, the stretching ratio is 4 times or more, preferably 5 times or more, and particularly preferably 5.5 times or more. There is no particular upper limit to the stretching ratio, but from the viewpoint of preventing breakage and the like, it is preferably 8 times or less.

[0114] A linearly polarizing layer produced by a manufacturing method using a substrate film can be obtained by laminating a protective layer and then peeling off the substrate film. This method makes it possible to further reduce the thickness of the linearly polarizing layer.

[0115] The thickness of the linearly polarizing layer, which is a PVA-based film, is preferably 1 μm or more, may be 2 μm or more, or may be 5 μm or more, and is preferably 30 μm or less, more preferably 15 μm or less, may be 10 μm or less, or may be 8 μm or less. If the thickness of the linearly polarizing layer is less than 1 μm, defects such as breakage may occur during processing, and if it exceeds 30 μm, the optical film becomes too thick, which is inappropriate.

[0116] <First Protective Layer 10 and Second Protective Layer 9> (First Resin Film 4 and Second Resin Film 9) As the protective layers, for example, protective films (first resin film and second resin film) are used, which are films formed from a thermoplastic resin that is excellent in transparency, mechanical strength, thermal stability, moisture blocking properties, isotropy, stretchability, etc. The protective films are preferably laminated on the linear polarizing layer via an attachment layer.

[0117] Specific examples of thermoplastic resins for forming the protective films (first resin film and second resin film) include cellulose resins such as triacetyl cellulose; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; polyethersulfone resins; polysulfone resins; polycarbonate resins; polyamide resins such as nylon and aromatic polyamide; polyimide resins; polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers; cyclic polyolefin resins having cyclo- and norbornene structures (also referred to as norbornene-based resins); (meth)acrylic resins; polyarylate resins; polystyrene resins; polyvinyl alcohol resins, and mixtures thereof. The thickness of the protective film is preferably thin from the viewpoint of optical properties, but if it is too thin, the strength decreases and the processability becomes poor. The appropriate thickness of the protective film is 5 μm or more and 100 μm or less, preferably 10 μm or more and 80 μm or less, and more preferably 15 μm or more and 70 μm or less.

[0118] The protective layer may have anti-reflection properties, anti-glare properties, hard coat properties, etc. (Hereinafter, a protective layer having such properties may be referred to as a "functional protective layer.") When the protective layer is not a functional protective layer, a surface functional layer such as an anti-reflection layer, an anti-glare layer, or a hard coat layer may be provided on one side of the linear polarizing plate. The surface functional layer is preferably provided so as to be in direct contact with the protective layer. The surface functional layer is preferably provided on the side of the protective layer opposite to the linear polarizing layer side.

[0119] The first protective layer provided on the pressure-sensitive adhesive layer side of the polarizer may be a laminate of a retardation layer, a first resin film, and a hard coat layer.

[0120] (Retardation Layer 5) The retardation layer is an optical element that exhibits retardation in the in-plane or thickness direction, and includes at least one retardation film. The retardation film may be one, or two or more retardation films may be bonded together with a known adhesive or pressure-sensitive adhesive. The retardation film is a film that exhibits retardation in the in-plane or thickness direction, and may be a stretched film or may include a cured layer of a polymerizable liquid crystal compound.

[0121] When the retardation film is a stretched film, a conventionally known stretched film can be used, and a resin film can be used that has been given a retardation by uniaxially or biaxially stretching. Examples of the resin film that can be used include, but are not limited to, cellulose films such as triacetyl cellulose and diacetyl cellulose, polyester films such as polyethylene terephthalate, polyethylene isophthalate and polybutylene terephthalate, acrylic resin films such as polymethyl (meth) acrylate and polyethyl (meth) acrylate, polycarbonate films, polyethersulfone films, polysulfone films, polyimide films, polyolefin films, and polynorbornene films.

[0122] When the retardation film includes the cured material layer, a known polymerizable liquid crystal compound can be used as the polymerizable liquid crystal compound. The polymerizable liquid crystal compound is a compound that has at least one polymerizable group and has liquid crystallinity.

[0123] The polymerizable group possessed by the polymerizable liquid crystal compound refers to a group that participates in a polymerization reaction, and is preferably a photopolymerizable group. The photopolymerizable group refers to a group that can participate in a polymerization reaction by an active radical or acid generated from a photopolymerization initiator. Examples of the polymerizable group include a vinyl group, a vinyloxy group, a 1-chlorovinyl group, an isopropenyl group, a 4-vinylphenyl group, a (meth)acryloyloxy group, an oxiranyl group, an oxetanyl group, a styryl group, and an allyl group. Among these, a (meth)acryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferred, and an acryloyloxy group is more preferred. The liquid crystallinity possessed by the polymerizable liquid crystal compound may be thermotropic liquid crystal or lyotropic liquid crystal, and when thermotropic liquid crystals are classified by the degree of order, they may be nematic liquid crystal or smectic liquid crystal. When two or more polymerizable liquid crystal compounds are used in combination to form a cured product layer of the polymerizable liquid crystal compound, it is preferable that at least one of the polymerizable liquid crystal compounds has two or more polymerizable groups in the molecule.

[0124] When the retardation film includes the cured product layer, the retardation film may include an alignment film. The alignment film has an alignment regulating force for aligning the polymerizable liquid crystal compound in a desired direction. The alignment film may be a vertical alignment film in which the molecular axis of the polymerizable liquid crystal compound is aligned vertically with respect to the planar direction of the optical laminate, a horizontal alignment film in which the molecular axis of the polymerizable liquid crystal compound is aligned horizontally with respect to the planar direction of the optical laminate, or an inclined alignment film in which the molecular axis of the polymerizable liquid crystal compound is aligned at an angle with respect to the planar direction of the optical laminate.

[0125] The cured product layer can be formed by applying a retardation film-forming composition containing a polymerizable liquid crystal compound, a solvent, and, if necessary, various additives onto an alignment film to form a coating film, and then solidifying (curing) the coating film. Alternatively, the cured product layer can be formed by applying the composition onto a substrate film to form a coating film, and then stretching the coating film together with the substrate film. In addition to the polymerizable liquid crystal compound and solvent, the composition may also contain a polymerization initiator, a reactive additive, a leveling agent, a polymerization inhibitor, etc. Known polymerizable liquid crystal compounds, solvents, polymerization initiators, reactive additives, leveling agents, polymerization inhibitors, etc. can be used as appropriate. As the substrate film, a film made of a resin material described as the thermoplastic resin used to form the protective film as the protective layer can be used.

[0126] (Hard Coat Layer 3) The hard coat layer is a layer provided to improve the hardness, scratch resistance, etc. of the first protective layer. The hard coat layer is, for example, a cured layer of a photocurable composition (composition for forming a hard coat layer) containing a photocurable resin and a photopolymerization initiator.

[0127] Examples of photocurable resins include acrylic resins, silicone resins, polyester resins, urethane resins, amide resins, and epoxy resins.

[0128] When the hard coat layer-forming composition is a radical curable composition, a radical polymerization initiator can be used as the photopolymerization initiator. Examples of the radical polymerization initiator include an α-hydroxyacetophenone-based photopolymerization initiator, an α-aminoacetophenone-based photopolymerization initiator, an acylphosphine oxide-based photopolymerization initiator, and an intramolecular hydrogen abstraction photopolymerization initiator. Among these, from the viewpoint of facilitating a shortening of the curing time of the hard coat layer-forming composition, an α-hydroxyacetophenone-based photopolymerization initiator and an α-aminoacetophenone-based photopolymerization initiator are preferred.

[0129] The hard coat layer may contain additives to improve its strength. The additives are not limited, and examples thereof include inorganic fine particles, organic fine particles, and mixtures thereof.

[0130] The thickness of the hard coat layer may be, for example, 0.1 μm or more and 10 μm or less, and preferably 0.5 μm or more and 5 μm or less.

[0131] <First attaching layer 6 and second attaching layer 8> The polarizer and the first and second protective layers may be attached to each other by an attaching layer. The attaching layer is a pressure-sensitive adhesive layer or an adhesive layer. When the attaching layer is a pressure-sensitive adhesive layer, it can be formed using a known pressure-sensitive adhesive composition. Furthermore, the pressure-sensitive adhesive composition used to form the pressure-sensitive adhesive layer 1 described above may be used as the pressure-sensitive adhesive composition.

[0132] When the attachment layer is an adhesive layer, the adhesive layer can be formed by curing a curable component in an adhesive composition. The adhesive composition for forming the adhesive layer is an adhesive other than a pressure-sensitive adhesive (pressure-sensitive adhesive), such as a water-based adhesive or an active energy ray-curable adhesive.

[0133] An example of an aqueous adhesive is an adhesive in which a polyvinyl alcohol resin is dissolved or dispersed in water. When an aqueous adhesive is used, the drying method is not particularly limited, but for example, a drying method using a hot air dryer or an infrared dryer can be used.

[0134] Examples of the active energy ray-curable adhesive include solvent-free active energy ray-curable adhesives containing a curable compound that cures when irradiated with active energy rays such as ultraviolet light, visible light, electron beams, and X-rays. Use of a solvent-free active energy ray-curable adhesive can improve adhesion between layers.

[0135] <Separate Film> The optical laminate may have a separate film attached to the surface of its pressure-sensitive adhesive layer to protect the surface of the pressure-sensitive adhesive layer until use. An optical laminate provided with such a separate film can be produced, for example, by applying the above-mentioned pressure-sensitive adhesive composition to a separate film to form a pressure-sensitive adhesive layer, and then laminating a polarizing plate on the resulting pressure-sensitive adhesive layer; applying the pressure-sensitive adhesive composition to a polarizing plate to form a pressure-sensitive adhesive layer, and then laminating a separate film on the pressure-sensitive adhesive surface to protect it; applying the above-mentioned pressure-sensitive adhesive composition to a separate film to form a pressure-sensitive adhesive layer, laminating another separate film on the resulting pressure-sensitive adhesive layer, and then peeling off one of the separate films to laminate a polarizing plate on the exposed pressure-sensitive adhesive surface. In particular, the method of applying the above-mentioned pressure-sensitive adhesive composition to a separate film to form a pressure-sensitive adhesive layer, laminating another separate film on the resulting pressure-sensitive adhesive layer, and then peeling off one of the separate films to laminate a polarizing plate on the exposed pressure-sensitive adhesive surface is preferred from the viewpoint of stabilizing the physical properties of the pressure-sensitive adhesive during the curing period. The separate film may be, for example, a film made of various resins such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, or polyarylate as a base material, and the surface of this base material to be bonded to the pressure-sensitive adhesive layer may be subjected to a release treatment such as silicone treatment.

[0136] The optical layered body of the present invention can moderate the increase in adhesion to a substrate due to heat and has good reworkability, and therefore can be suitably used for applications in which it is attached to a substrate such as glass in an image display device or the like.

[0137] [Image display device] The image display device according to the present invention includes the optical laminate according to the present invention. The image display device includes, for example, a glass substrate and an optical laminate bonded to the glass substrate. A metal layer such as metal wiring may be provided on a part of the surface of the glass substrate facing the optical laminate. The metal layer may be a transparent electrode layer made of a metal oxide such as ITO.

[0138] During the manufacture of an image display device, if any defect occurs after the optical laminate is attached to a glass substrate, it may be necessary to peel the optical laminate from the glass substrate and reattach another optical laminate to the glass substrate, a so-called reworking operation. Here, it may take a long time from the attachment of the optical laminate to the glass substrate to the peeling, or the image display device may be exposed to the elements. However, the optical laminate according to the present invention can moderate the increase in adhesion to the substrate due to heat and has good reworkability, so that the optical laminate can be easily peeled from the glass substrate and the adhesive can be prevented from remaining on the surface of the glass substrate after peeling.

[0139] Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments. For example, the optical laminate may not have a hard coat layer between the coating layer and the first resin film, and the coating layer and the first resin film may be in direct contact with each other. In addition, the optical laminate may not have a second protective layer. In addition, the optical laminate may not have a retardation layer, and the polarizing plate may be a linear polarizing plate.

[0140] 1 has been described as an optical laminate 100 including a polarizing plate 20, the optical laminate may be a laminate including an optical film having another optical function, as long as it includes a resin film, a coating layer, and a pressure-sensitive adhesive layer in this order. For example, the optical laminate may include, instead of the polarizing plate 20 in FIG. 1, a retardation plate having a protective layer provided on one or both sides of a retarder; a reflective film; a semi-transmissive reflective film; a brightness-enhancing film; a film with an anti-glare function; or the like. These optical films may be used alone or in combination of two or more.

[0141] The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. Hereinafter, "parts" and "%" representing amounts used or contents are based on mass unless otherwise specified.

[0142] <Production Example 1> A mixed solution of 86.4 parts of ethyl acetate, 68.7 parts of butyl acrylate, 20 parts of methyl acrylate, 10 parts of methyl methacrylate, 1.0 part of 2-hydroxyethyl acrylate, and 0.3 parts of acrylic acid was charged into a reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer, and a stirrer. The air inside the vessel was purged with nitrogen gas to remove oxygen, and the internal temperature was raised to 60°C. Thereafter, the entire amount of a solution prepared by dissolving 0.10 parts of azobisisobutyronitrile (polymerization initiator) in 13.7 parts of ethyl acetate was added. After addition of the polymerization initiator, the temperature was maintained at 60°C for 4 hours. Ethyl acetate was then added to adjust the concentration of the (meth)acrylic resin to 20% by mass, thereby preparing an ethyl acetate solution of the (meth)acrylic resin.

[0143] The weight-average molecular weight (Mw) and number-average molecular weight (Mn) of the obtained (meth)acrylic resin were measured. Mw and Mn were measured in terms of standard polystyrene using a GPC apparatus with three columns connected in series: one "TSKgel guard column HHR-H(S)" manufactured by Tosoh Corporation and two "TSKgel GMHHR-H" columns, and tetrahydrofuran as the eluent under the conditions of a sample concentration of 2 mg / mL, a sample introduction amount of 100 μL, a temperature of 40° C., and a flow rate of 1 mL / min.

[0144] The obtained (meth)acrylic resin was subjected to molecular weight fractionation of a high molecular weight region component and a low molecular weight region component. As the high molecular weight region component, in the chromatogram obtained by GPC measurement, the component in the region of 10% of the high molecular weight side of the peak derived from the (meth)acrylic resin was fractionated, and as the low molecular weight region component, in the chromatogram obtained by GPC measurement, the component in the region of 10% of the low molecular weight side of the peak derived from the (meth)acrylic resin was fractionated. A GPC apparatus (LaboACE LC-7080 manufactured by Japan Analytical Industry Co., Ltd.) was used as a column, and a total of three columns, one "TSKgel guardcolumnHHR-H (S)" manufactured by Tosoh Corporation and two "TSKgel GMHHR-H", were connected in series and arranged, and tetrahydrofuran was used as the eluent, and molecular weight fractionation was performed under the conditions of a sample concentration of 2.5 mg / mL, a sample introduction amount of 2 mL, room temperature, and a flow rate of 6 mL / min.

[0145] After molecular weight fractionation of the obtained (meth)acrylic resin, the glass transition temperature (Tg) of the high molecular weight region component and the low molecular weight region component was measured. Tg was measured using an EXSTAR DSC6000 differential scanning calorimeter (DSC) manufactured by SII Nanotechnology, Inc. under conditions of a measurement temperature range of -80 to 50°C and a heating rate of 10°C / min in a nitrogen atmosphere. The monomer composition of the monomer mixture used, the Mw and molecular weight distribution (Mw / Mn) of the obtained (meth)acrylic resin, and Tg are summarized in Table 1.

[0146]

[0147] The abbreviations in the "Monomer composition" column in Table 1 represent the following monomers: BA: butyl acrylate MA: methyl acrylate MMA: methyl methacrylate HEA: 2-hydroxyethyl acrylate AA: acrylic acid

[0148] To an ethyl acetate solution of the (meth)acrylic resin (resin concentration: 20%), a crosslinking agent, a silane compound, and an antistatic agent (ionic compound) were mixed in the amounts (parts by mass) shown in Table 2 relative to 100 parts by mass of the solid content of the solution, and ethyl acetate was further added so that the solid content concentration became 14% by mass to prepare PSA composition 1. In Table 2, the blending amounts (parts by mass) of the (meth)acrylic resin, crosslinking agent, silane compound, and ionic compound are calculated as solid content amounts.

[0149] <Preparation Example 2> As shown in Table 2, Pressure-sensitive adhesive composition 2 was prepared in the same manner as for the preparation of Pressure-sensitive adhesive composition 1, except that no ionic compound was added.

[0150]

[0151] The "type" of each component in Table 2 refers to the following material: (Crosslinking agent) B: D-103 (trade name, ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate, manufactured by Mitsui Chemicals, Inc., solid content concentration 75% by mass) (Silane compound) C: KBM-4803 (trade name, 8-glycidoxyoctyltrimethoxysilane, manufactured by Shin-Etsu Chemical Co., Ltd.) (Ionic compound) D: methyltributylammonium bis(trifluoromethylsulfonyl)imide

[0152] <Production Example 3> The components shown in Table 3 were mixed and stirred in the amounts (parts by mass) shown in Table 3 to obtain a composition for forming a hard coat layer HC-1.

[0153]

[0154] The following materials were used as the components in Table 3: Photocurable resin: Beamset 710 (trade name, pentaerythritol polyacrylate, manufactured by Arakawa Chemical Industries, Ltd.) Photopolymerization initiator A: Omnirad 2959 (trade name, manufactured by IGM Resins) Solvent: methyl ethyl ketone

[0155] <Production Example 4> 50 g of a modified polyvinyl alcohol resin containing an acetoacetyl group (manufactured by Mitsubishi Chemical Corporation, product name: Gohsenex Z-410) was dissolved in 950 g of pure water, heated at 90°C for 2 hours, and then cooled to room temperature to obtain a PVA solution. This PVA solution, pure water, maleic acid, glyoxal, and urea were blended so that the concentration of the polyvinyl alcohol resin was 3.0 mass%, the concentration of maleic acid was 0.01 mass%, the concentration of glyoxal was 0.15 mass%, and the concentration of urea was 0.1 mass%, to obtain an aqueous adhesive.

[0156] [Example 1] <Preparation of Retardation Layer with Substrate Layer> An alignment film (thickness 40 nm) and a liquid crystal cured film (thickness 0.5 μm) (these are collectively referred to as "retardation layer") were formed on a transparent film substrate (polyolefin resin film, thickness 24 μm) as a substrate layer (resin film) by the method described in

[0261] to

[0266] of JP2016-027431A, to obtain a retardation layer with a substrate layer.

[0157] <Formation of hard coat layer> The composition for forming a hard coat layer HC-1 prepared in Production Example 3 was applied by bar coating to the surface of the substrate layer side of the retardation layer with the substrate layer prepared above so that the film thickness after drying would be about 1 μm. The coating film was dried in an oven at 60° C. for 150 seconds, and then irradiated with an electrodeless lamp H bulb manufactured by Fusion UV Systems at an illuminance of 400 mW / cm ２ , light intensity 300mJ / cm ２The coating film was irradiated with ultraviolet light of 1000 kJ / cm 2 to form a hard coat layer.

[0158] <Preparation of Polarizer> A 30 μm-thick polyvinyl alcohol (PVA) resin film was immersed in pure water at a temperature of 21.5° C. for 80 seconds (swelling treatment), and then immersed in an aqueous solution containing 1.0 mM iodine and having a mass ratio of potassium iodide / boric acid / water of 2 / 2 / 100 at a temperature of 23° C. for 55 seconds (dyeing step). Thereafter, the film was immersed in an aqueous solution containing 1.0 mM iodine and having a mass ratio of potassium iodide / boric acid / water of 2.5 / 4 / 100 at a temperature of 63° C. for 76 seconds (first crosslinking step). Subsequently, the film was immersed in an aqueous solution containing 3.0 mM potassium iodide / boric acid / zinc chloride / water in a mass ratio of 3 / 5.5 / 0.6 / 100 at a temperature of 45° C. for 10 seconds (second crosslinking step, metal ion treatment step). Thereafter, the film was immersed in a washing bath for washing (washing step) and dried at a temperature of 38° C. (drying step) to obtain a polarizer having a thickness of 12 μm in which iodine was adsorbed and oriented in the PVA-based resin film. Stretching was performed mainly in the dyeing step and the first crosslinking step, and the total stretching ratio was 5.85 times.

[0159] <Preparation of Polarizing Plate> A retardation layer with a substrate layer on which a hard coat layer was formed as described above was prepared as protective layer (1), and a triacetyl cellulose film (manufactured by Fujifilm Corporation, product name "TJ40UL", thickness: 40 μm) was prepared as protective layer (2). Two types of protective layers (1) and (2) were prepared by subjecting protective layer (2) to a saponification treatment.

[0160] The two types of protective layers (1) and (2) prepared above were bonded to each surface of the polarizer prepared above using a roll laminator via the aqueous adhesive prepared in Production Example 4, and then dried at a temperature of 80°C for 5 minutes to obtain a polarizing plate (layer structure: protective layer (2) / adhesive layer / polarizer / adhesive layer / protective layer (1)). Here, the protective layer (1) was bonded so that its retardation layer surface faced the polarizer. The aqueous adhesive interposed between the polarizer and the protective layers (1) and (2) was adjusted so that the thickness of the adhesive layer after drying was 100 nm on both sides.

[0161] <Preparation of Coating Layer (Conductive Layer)> A CNT-based conductive coating agent (manufactured by Nagase ChemteX Corporation, trade name "Denatron C-169PF-A") and a crosslinking agent for a CNT-based conductive coating agent (manufactured by Nagase ChemteX Corporation, trade name "Denatron C-169PF-B") were mixed in a ratio (mass ratio) of Denatron C-169PF-A:C-169PF-B = 3:2, and the mixture was stirred for 10 minutes to prepare a coating liquid for forming a coating layer with a concentration of 1.5%. The hard coat layer surface of the protective layer (1) of the polarizing plate prepared above was subjected to a corona treatment (4.0 KJ / m ２ ) was applied to the film, the coating liquid prepared above was applied, and the film was dried by heating at 100°C for 3 minutes to form a coating layer (conductive layer) with a thickness of 50 nm. In this way, a polarizing plate with a coating layer was obtained.

[0162] <Preparation of Polarizing Plate with Pressure-Sensitive Adhesive Layer> The pressure-sensitive adhesive composition prepared in Preparation Example 1 above was applied to the release-treated surface of a separate film (manufactured by Mitsubishi Chemical Corporation, product name "Diafoil MRV38 (V04)") made of a release-treated polyethylene terephthalate film using an applicator so that the thickness after drying would be 25 μm, and the applied film was dried at 100° C. for 1 minute to prepare a pressure-sensitive adhesive layer (pressure-sensitive adhesive sheet). The surface of the pressure-sensitive adhesive layer prepared above opposite to the separate film (pressure-sensitive adhesive layer surface) was bonded to the coating layer surface of the coating layer-attached polarizing plate prepared above using a laminator, and then aged for 7 days under conditions of a temperature of 23° C. and a relative humidity of 60%, to obtain a pressure-sensitive adhesive layer-attached polarizing plate.

[0163] Example 2 A polarizing plate with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the concentration of the coating liquid for forming the coating layer was 0.15% and the thickness after drying was 5 nm.

[0164] Comparative Examples 1 and 2 A polarizing plate with a pressure-sensitive adhesive layer was produced in the same manner as in Example 1, except that the structures shown in Table 4 were used to produce the pressure-sensitive adhesive layer and the coating layer.

[0165] [Measurement of Adhesion Strength to Substrate After Heat Treatment / Humid Heat Treatment] The polarizing plates with pressure-sensitive adhesive layers obtained in the Examples and Comparative Examples were cut to a width of 25 mm to prepare test specimens. The separate film was peeled from the test specimen, and the pressure-sensitive adhesive layer surface of the test specimen was attached to a glass substrate (alkali-free glass) using a laminator (manufactured by Fujipla Inc., product name "LPC1506") under a room temperature and humidity environment (23°C, 50% RH). After that, the end of the test specimen was pulled at an angle of 180°C at a rate of 300 mm / min under a room temperature and humidity environment, and the adhesion strength when peeled from the glass substrate was measured initially (0 hours), and after 24 hours of heat treatment at 50°C or 24 hours of moist heat treatment at 65°C, 93% RH. The measurement was performed using a Tensilon universal testing machine (product name "STB-1110-HS10") manufactured by A&D Co., Ltd. The results are shown in Table 4. It can be said that the lower the adhesion strength to the substrate after the heat treatment and the moist heat treatment, the better the reworkability. In both the Examples and Comparative Examples, no adhesive remained on the glass substrate surface after peeling.

[0166] [Measurement of Electrostatic Charge Immediately After Peeling Off Separation Film] The polarizing plates with adhesive layers obtained in the Examples and Comparative Examples were cut into 20 cm squares to prepare test specimens. The protective layer (2) side of the test specimen was attached to a glass substrate (alkali-free glass) with adhesive tape attached, and the adhesive layer of the polarizing plate was grounded. The edge of the separate film was pulled at an angle of 180° at a speed of 30 m / min under a room temperature and humidity environment (23°C, 50% RH), and the electrostatic charge upon peeling from the adhesive layer was measured. The electrostatic charge measurement was performed using a static electricity meter (product name "SK-035 / 200") manufactured by Keyence Corporation. The results are shown in Table 4.

[0167] [Measurement of Surface Resistance of Coating Layer] Using a Hiresta UP (product name "MCP-HT450") manufactured by Mitsubishi Chemical Corporation, the surface resistance of the coating layer of the polarizing plates with a coating layer obtained in the Examples and Comparative Examples was measured at an applied voltage of 10 V. The results are shown in Table 4.

[0168]

[0169] 1...adhesive layer, 2...coating layer, 3...hard coating layer, 4...first resin film, 5...retardation layer, 6...first bonding layer, 7...polarizer, 8...second bonding layer, 9...second resin film (second protective layer), 10...first protective layer, 20...polarizing plate, 100...optical laminate.

Claims

1. An optical laminate having a resin film, a coating layer, and an adhesive layer in this order, the coating layer containing carbon nanotubes, and the adhesive layer containing a (meth)acrylic resin (A), a crosslinking agent (B), a silane compound (C), and an antistatic agent (D).

2. The optical laminate according to claim 1, wherein the antistatic agent (D) is an ionic compound comprising a nitrogen-containing organic cation and an anion.

3. The optical laminate according to claim 2, wherein the nitrogen atom-containing organic cation is a cation represented by the following formula (I): [In formula (I), R ５ , R ６ , R ７ and R ８ each independently represents a hydrogen atom, an optionally substituted alkyl group, an optionally substituted alkenyl group, an optionally substituted alkynyl group, an optionally substituted aryl group, or an optionally substituted heterocyclic group; R ５ , R ６ , R ７ and R ８ Adjacent substituents may be bonded together to form a ring.

4. The optical laminate according to claim 2, wherein the anion is a fluorine atom-containing anion.

5. The optical laminate according to claim 4, wherein the fluorine atom-containing anion is an anion represented by the following formula (II): [Y(SO ２ C ｑ F ２ｑ＋１ ) ｐ ] － (II) [In formula (II), Y represents a carbon atom or a nitrogen atom, p is 3 when Y is a carbon atom, and p is 2 when Y is a nitrogen atom, and q represents an integer of 0 to 10.] 6. The optical laminate according to claim 2, wherein the anion is at least one selected from the group consisting of a p-toluenesulfonate anion, a dimethylphosphinate anion, a thiocyanate anion, a carbonate anion, a tetraarylborate anion, and a dicyanamide anion.

7. The optical laminate according to claim 1, further comprising a hard coat layer between the resin film and the coating layer.

8. The optical laminate according to claim 1, further comprising a polarizer on the opposite side of the resin film to the coating layer.

9. The optical laminate according to claim 8, further comprising a second resin film on the opposite side of the polarizer to the resin film.

10. An image display device comprising the optical laminate according to any one of claims 1 to 9.

Images