KR102595697B1 - Adhesive composition, adhesive layer and optical member with adhesive layer - Google Patents

Abstract

An adhesive composition having good durability when bonded as an adhesive layer to the surface of an optical member, an adhesive layer containing the same, and an optical member with an adhesive layer provided with the adhesive layer are provided.
The content of structural units derived from a (meth)acrylic monomer having a hydroxyl group is 0.2 to 4% by weight, the content of structural units derived from a (meth)acrylic monomer having a carboxyl group is 0 to 4% by weight, and the glass transition temperature is - An adhesive composition containing 100 parts by weight of a (meth)acrylic resin (A) at a temperature of 55° C. or higher and 0.1 to 1 part by weight of an isocyanate-based crosslinking agent (B) in which an isocyanate group is bonded to a carbon atom constituting the aliphatic skeleton, and an adhesive layer containing the same. And an optical member with an adhesive layer provided with the adhesive layer is provided.

Description

Adhesive composition, adhesive layer, and optical member with adhesive layer attached {ADHESIVE COMPOSITION, ADHESIVE LAYER AND OPTICAL MEMBER WITH ADHESIVE LAYER}

The present invention relates to an adhesive composition, an adhesive layer containing the same, and an optical member provided with the adhesive layer.

Polarizers, which are formed by laminating and bonding a protective film to one or both sides of a polarizer, are used in image display devices such as liquid crystal displays and organic electroluminescence (organic EL) displays, especially in mobile phones, smartphones, and tablet-type terminals. It is an optical member widely used in various mobile devices. Optical members such as polarizers are often used by bonding them to other members (e.g., optical members such as liquid crystal cells in liquid crystal display devices) through an adhesive layer [e.g., Japanese Patent Application Laid-Open No. 2010-229321 (Patent Document 1) reference〕. For this reason, in most cases, for example, polarizing plates are distributed on the market in the form of polarizing plates with an adhesive layer in which an adhesive layer is previously provided on one side.

[Patent Document 1] Japanese Patent Publication No. 2010-229321

Durability is required for the adhesive composition used in the adhesive layer for joining optical members. That is, the adhesive layer bonded to the optical member and inserted into the image display device, etc. may be placed in a high temperature or high temperature and high humidity environment, or in an environment where high temperature and low temperature repeat, and the adhesive layer is adjacent to the adhesive layer even under these environments. It is required to be able to suppress problems that may occur due to changes in the dimensions of the optical member. The above problems include lifting and peeling at the interface between the adhesive layer and the optical member adjacent to it, and foaming of the adhesive layer.

However, conventional adhesive compositions sometimes have insufficient durability when bonded to an optical member as an adhesive layer, and the surface of the optical member to which the adhesive layer is bonded is difficult to effectively activate even by surface activation treatment such as corona treatment. In particular, in the case of the surface, durability was sometimes insufficient.

The present invention provides an adhesive composition having good durability when bonded as an adhesive layer to the surface even if the surface of an optical member is difficult to be effectively activated even by surface activation treatment, an adhesive layer containing the same, and a adhesive layer comprising the adhesive layer. The purpose is to provide an optical member with an adhesive layer.

The present invention provides an adhesive composition, an adhesive layer, and an optical member with an adhesive layer shown below.

[1] The content of structural units derived from (meth)acrylic monomers having a hydroxyl group is 0.2 to 4% by weight, the content of structural units derived from (meth)acrylic monomers having a carboxyl group is 0 to 4% by weight, and glass transition occurs. 100 parts by weight of (meth)acrylic resin (A) having a temperature of -55°C or higher,

0.1 to 1 part by weight of an isocyanate-based crosslinking agent (B) in which an isocyanate group is bonded to the carbon atom constituting the aliphatic skeleton

An adhesive composition containing.

[2] The pressure-sensitive adhesive composition according to [1], wherein the isocyanate group is bonded to a carbon atom constituting a methylene group.

[3] The pressure-sensitive adhesive composition according to [1] or [2], wherein the content of structural units derived from the (meth)acrylic monomer having the hydroxyl group is 3.5% by weight or less.

[4] The adhesive composition according to any one of [1] to [3], further containing an ionic compound (C).

[5] The adhesive composition according to any one of [1] to [4], further containing a silane compound (D).

[6] An adhesive layer containing the adhesive composition according to any one of [1] to [5].

[7] An optical member with an adhesive layer comprising an optical member and the adhesive layer described in [6] laminated thereon.

[8] The optical member with an adhesive layer according to [7], wherein the surface of the optical member on which the adhesive layer is laminated has a contact angle change rate of 40% or less when corona treatment is performed.

[9] The optical member includes a polarizer and a protective film laminated thereon,

The optical member with an adhesive layer according to [8], wherein the surface is a surface of the protective film.

[10] The optical member with an adhesive layer according to [8] or [9], wherein the surface is a corona-treated surface.

According to the present invention, a highly durable adhesive composition, an adhesive layer containing the adhesive layer, and an optical member with an adhesive layer provided with the adhesive layer can be provided.

1 is a schematic cross-sectional view showing an example of an optical member with an adhesive layer according to the present invention.
Figure 2 is a schematic cross-sectional view showing another example of an optical member with an adhesive layer according to the present invention.
Figure 3 is a schematic cross-sectional view showing another example of an optical member with an adhesive layer according to the present invention.
Figure 4 is a schematic cross-sectional view showing another example of an optical member with an adhesive layer according to the present invention.

<Adhesive composition>

[1] (meth)acrylic resin (A)

The (meth)acrylic resin (A) is a polymer containing a structural unit derived from a (meth)acrylic monomer having a hydroxyl group, and preferably, in addition to this structural unit, has the following formula (I):

It is a polymer containing as a main component a structural unit derived from (meth)acrylic acid ester represented by . In this specification, “(meth)acrylic” means acrylic and/or methacrylic, and “(meth)” when referring to (meth)acrylate, etc. has the same meaning.

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

Specific examples of (meth)acrylic acid esters represented by formula (I) include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, and n-(meth)acrylic acid. -Linear (meth)acrylic acid alkyl esters such as octyl and lauryl (meth)acrylate; Includes branched (meth)acrylic acid alkyl esters such as isobutyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and isooctyl (meth)acrylate.

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

The (meth)acrylic acid ester represented by formula (I) may be used individually or in combination of two or more types. Among these, (meth)acrylic acid ester preferably contains n-butyl acrylate. The (meth)acrylic resin (A) preferably contains 50% by weight or more of structural units derived from n-butyl acrylate out of all structural units constituting it. Of course, in addition to n-butyl acrylate, other (meth)acrylic acid esters represented by formula (I) can also be used together.

The content of the structural unit derived from the (meth)acrylic acid ester represented by formula (I) is usually 60% by weight or more and less than 100% by weight of all structural units constituting the (meth)acrylic resin (A), and is preferably It is 70 to 99.9% by weight, and more preferably 80 to 99.6% by weight.

The (meth)acrylic resin (A) contains structural units derived from a (meth)acrylic monomer having a hydroxyl group. Containing this structural unit is advantageous in improving the adhesion between the adhesive layer and the optical member and the durability of the adhesive layer. A suitable example of a (meth)acrylic monomer having a hydroxyl group is a (meth)acrylic acid ester having a hydroxyl group. Specific examples of (meth)acrylic acid esters having a hydroxyl group include 2-hydroxyethyl (meth)acrylic acid, 3-hydroxypropyl (meth)acrylic acid, 4-hydroxybutyl (meth)acrylic acid, and 2-(meth)acrylic acid. Includes 2-hydroxyethoxy)ethyl, 2- or 3-chloro-2-hydroxypropyl (meth)acrylic acid, diethylene glycol mono(meth)acrylate, etc.

The content of the structural unit derived from the (meth)acrylic monomer having a hydroxyl group is 4% by weight or less, preferably 3.5% by weight or less, and more preferably 3.5% by weight or less, based on the total structural units constituting the (meth)acrylic resin (A). is 3% by weight or less. If the content of the structural unit derived from a (meth)acrylic monomer having a hydroxyl group exceeds 4% by weight, the durability of the adhesive layer, especially heat resistance, is insufficient. On the other hand, the content of the structural unit derived from the (meth)acrylic monomer having a hydroxyl group is usually 0.2% by weight or more, preferably 0.5% by weight or more, and more preferably 1.0% by weight or more. If the content of the structural unit derived from the (meth)acrylic monomer having a hydroxyl group is less than 0.2% by weight, the adhesion between the adhesive layer and the optical member and the durability of the adhesive layer are insufficient.

The (meth)acrylic resin (A) may contain a structural unit derived from a monomer having a polar functional group other than the (meth)acrylic monomer having a hydroxyl group. The monomer having this polar functional group is preferably a (meth)acrylic monomer having a polar functional group. Examples of the polar functional group possessed by the monomer include a carboxyl group (free carboxyl group), an amino group, and a heterocyclic group (for example, an epoxy group).

Specific examples of monomers having other polar functional groups include monomers having a carboxyl group such as (meth)acrylic acid, methacrylic acid, and β-carboxyethyl (meth)acrylate; Acryloylmorpholine, vinylcaprolactam, N-vinyl-2-pyrrolidone, vinylpyridine, tetrahydrofurfuryl (meth)acrylate, caprolactone modified tetrahydrofurfuryl acrylate, 3,4-epoxycyclohexyl Monomers having a heterocyclic group such as methyl (meth)acrylate, glycidyl (meth)acrylate, and 2,5-dihydrofuran; It includes monomers having an amino group different from the heterocycle, such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and dimethylaminopropyl (meth)acrylate. Monomers having different polar functional groups may be used individually or in combination of two or more types.

In addition to the (meth)acrylic monomer having a hydroxyl group, the combined use of a monomer having another polar functional group, especially a (meth)acrylic monomer having a carboxyl group, improves the adhesion between the adhesive layer and the optical member and the durability (especially heat resistance) of the adhesive layer. ) is advantageous in increasing.

The content of the structural unit derived from a monomer having another polar functional group, preferably a (meth)acrylic monomer having a carboxyl group, is preferably 0% by weight or more, based on the total structural units constituting the (meth)acrylic resin (A). is 4% by weight or less. As described above, the (meth)acrylic resin (A) preferably contains a structural unit derived from a (meth)acrylic monomer having a carboxyl group, and its content is determined by the overall composition of the (meth)acrylic resin (A). In units, it is preferably 0.02% by weight or more, more preferably 0.05% by weight or more, and even more preferably 0.1% by weight or more. If the content of structural units derived from monomers having other polar functional groups is less than 0.02% by weight, it is difficult to recognize the effect of use. On the other hand, the content of the structural unit derived from a monomer having another polar functional group, preferably a (meth)acrylic monomer having a carboxyl group, is preferably 4% by weight of the total structural units constituting the (meth)acrylic resin (A). or less, and more preferably 3.5% by weight or less. If the content of structural units derived from monomers having other polar functional groups exceeds 4% by weight, the durability of the adhesive layer, especially heat resistance, tends to be insufficient. Structural units derived from monomers having all polar functional groups, including (meth)acrylic monomers having hydroxyl groups, are usually 1 to 10% by weight, preferably 1 to 10% by weight, out of the total structural units constituting the (meth)acrylic resin (A). It is 1.1~8% by weight.

The (meth)acrylic resin (A) is a monomer having one olefinic double bond and at least one aromatic ring in the molecule (however, excluding monomers having the above formula (I) or the above polar functional group). It may additionally contain derived structural units. Suitable examples include (meth)acrylic monomers having an aromatic ring. (meth)acrylic monomers having such an aromatic ring include neopentyl glycol benzoate (meth)acrylate and the like, and are particularly represented by the following formula (II):

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

In the formula (II), R ³ represents a hydrogen atom or a methyl group, n represents an integer of 1 to 8, and R ⁴ represents a hydrogen atom, an alkyl group, an aralkyl group, or an aryl group. When R ⁴ is an alkyl group, the carbon number may be approximately 1 to 9, if it is an aralkyl group, the carbon number may be approximately 7 to 11, and if it is an aryl group, the carbon number may be approximately 6 to 10.

In formula (II), ^alkyl groups having 1 to 9 carbon atoms include methyl, butyl, nonyl, etc., aralkyl groups having 7 to 11 carbon atoms include benzyl, phenethyl, naphthylmethyl, etc., and aralkyl groups having 6 to 10 carbon atoms include benzyl, phenethyl, and naphthylmethyl. Examples of the aryl group include phenyl, tolyl, naphthyl, etc.

Specific examples of phenoxyethyl group-containing (meth)acrylic acid esters represented by formula (II) include 2-phenoxyethyl (meth)acrylate, 2-(2-phenoxyethoxy)ethyl (meth)acrylate, and ethylene oxide-modified ester. Includes (meth)acrylic acid ester of nonylphenol, 2-(o-phenylphenoxy)ethyl (meth)acrylate, etc. Phenoxyethyl group-containing (meth)acrylic acid ester may be used individually or in combination of two or more types. Among them, (meth)acrylic acid ester containing a phenoxyethyl group includes 2-phenoxyethyl (meth)acrylate, 2-(o-phenylphenoxy)ethyl (meth)acrylate, and/or 2-(2-)(meth)acrylic acid. It is preferred that it contains phenoxyethoxy)ethyl.

The content of the structural unit derived from the monomer having an aromatic ring is usually 0 to 20% by weight (for example, 6 to 12% by weight) of all structural units that constitute the (meth)acrylic resin (A). However, in order to keep the glass transition temperature of the (meth)acrylic resin (A) within a predetermined range described later, it may be preferable not to contain a structural unit derived from a monomer having an aromatic ring.

The (meth)acrylic resin (A) is derived from monomers other than the (meth)acrylic acid ester of formula (I) described above, a monomer having a polar functional group, and a monomer having an aromatic ring (hereinafter also referred to as “other monomers”). It may contain structural units that: Examples of other monomers include structural units derived from (meth)acrylic acid esters having an alicyclic structure in the molecule, structural units derived from styrene-based monomers, structural units derived from vinyl-based monomers, and multiple (meth)acrylates within the molecule. Structural units derived from monomers having a loyl group, structural units derived from (meth)acrylamide compounds, etc. are mentioned. As for other monomers, only one type may be used individually or two or more types may be used in combination.

The alicyclic structure in the (meth)acrylic acid ester having an alicyclic structure in the molecule is a cycloparaffinic structure with usually 5 or more carbon atoms, preferably about 5 to 7 carbon atoms. Specific examples of (meth)acrylic acid esters having an alicyclic structure include isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, dicyclofentanyl (meth)acrylate, cyclododecyl (meth)acrylate, and (meth)acrylic acid. Includes methylcyclohexyl, trimethylcyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, cyclohexylphenyl (meth)acrylate, cyclohexyl α-ethoxyacrylate, etc.

Specific examples of styrene-based monomers include styrene; Alkyl styrene such as methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, and octyl styrene; Halogenated styrene such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, and iodostyrene; Includes nitrostyrene, acetylstyrene, methoxystyrene, divinylbenzene, etc.

Specific 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 vinyl such as vinylpyridine, vinylpyrrolidone, and vinylcarbazole; Conjugated diene monomers such as butadiene, isoprene, and chloroprene; Includes acrylonitrile, methacrylonitrile, etc.

Specific examples of monomers having multiple (meth)acryloyl groups in the molecule include 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and 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. Monomers having a (meth)acryloyl group; It includes monomers having three (meth)acryloyl groups in the molecule, such as trimethylolpropane tri(meth)acrylate.

Specific examples of (meth)acrylamide compounds include N-methylol (meth)acrylamide, N-(2-hydroxyethyl)(meth)acrylamide, and 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, N-(3-dimethylaminopropyl)(meth)acrylamide, N-(1,1 -Dimethyl-3-oxobutyl)(meth)acrylamide, N-[2-(2-oxo-1-imidazolidinyl)ethyl](meth)acrylamide, 2-acryloylamino-2-methyl- 1-Propanesulfonic acid, N-(methoxymethyl)acrylamide, N-(ethoxymethyl)(meth)acrylamide, N-(propoxymethyl)(meth)acrylamide, N-(1-methylethoxymethyl) ) (meth)acrylamide, N-(1-methylpropoxymethyl)(meth)acrylamide, N-(2-methylpropoxymethyl)(meth)acrylamide [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-propoxyethyl)(meth)acrylamide, N-[2-(1-methylethoxy)ethyl](meth)acrylamide , N-[2-(1-methylpropoxy)ethyl](meth)acrylamide, N-[2-(2-methylpropoxy)ethyl](meth)acrylamide[alias: N-(2-isobutoxy) ethyl)(meth)acrylamide], N-(2-butoxyethyl)(meth)acrylamide, N-[2-(1,1-dimethylethoxy)ethyl](meth)acrylamide, etc. Among them, N-(methoxymethyl)acrylamide, N-(ethoxymethyl)acrylamide, N-(propoxymethyl)acrylamide, N-(butoxymethyl)acrylamide, and N-(2-methylpropyl). Oxymethyl)acrylamide is preferably used.

The (meth)acrylic resin (A) usually contains other monomers in an amount of 0 to 20% by weight, preferably 0 to 10% by weight, based on the total structural units constituting the resin (A).

The adhesive composition may contain two or more types of (meth)acrylic resin belonging to (meth)acrylic resin (A). Additionally, the adhesive composition may contain another (meth)acrylic resin that is different from the (meth)acrylic resin (A). An example of another (meth)acrylic resin is a (meth)acrylic resin that has a structural unit derived from the (meth)acrylic acid ester of formula (I) but does not have a polar functional group. However, the adhesive composition preferably contains (meth)acrylic resin (A) as the main component, and the content of (meth)acrylic resin (A) is preferably 60 weight of the total of all (meth)acrylic resins. % or more, more preferably 80 weight% or more, and even more preferably 90 weight% or more.

The (meth)acrylic resin (A) has a glass transition temperature (Tg) measured by differential scanning calorimetry (DSC) of -55°C or higher, preferably -50°C or higher. According to the pressure-sensitive adhesive composition according to the present invention containing the (meth)acrylic resin (A) with a Tg of -55°C or higher, the adhesion between the pressure-sensitive adhesive layer and the optical member and the durability of the pressure-sensitive adhesive layer can be improved. From the viewpoint of adhesion between the adhesive layer and the optical member, the Tg of the (meth)acrylic resin (A) is usually -20°C or lower, preferably -25°C or lower, and more preferably -30°C or lower.

The (meth)acrylic resin (A) preferably has a weight average molecular weight (Mw) in the range of 500,000 to 2 million, as calculated by gel permeation chromatography (GPC) in terms of standard polystyrene, and is in the range of 600,000 to 1.8 million. It is more preferable. When Mw is 500,000 or more, the adhesion between the adhesive layer and the optical member in a high-temperature, high-humidity environment improves, the possibility of floating or peeling between the adhesive layer and the optical member tends to decrease, and furthermore, the reworkability of the adhesive layer increases. This tends to improve. In addition, if Mw is 2 million or less, even if the dimensions of the optical member change when the adhesive layer is bonded to the optical member, the adhesive layer tends to follow the dimensional change and fluctuate, so the adhesion between the adhesive layer and the optical member is poor. It is advantageous in terms of the durability of the adhesive layer, and also, due to the above-mentioned followability, when the optical member with the adhesive layer is applied to a liquid crystal display device, there is no difference between the brightness of the peripheral portion and the brightness of the central portion of the liquid crystal cell, so that no white streaks or colors appear. Staining tends to be suppressed. The molecular weight distribution expressed by the ratio (Mw/Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) is usually about 2 to 10, and preferably 3 to 8.

The (meth)acrylic resin (A) or other (meth)acrylic resins that can be optionally used together can be produced by known methods such as solution polymerization, bulk polymerization, suspension polymerization, and emulsion polymerization. . In the production of (meth)acrylic resin, a polymerization initiator is usually used. The polymerization initiator is used in an amount of about 0.001 to 5 parts by weight based on a total of 100 parts by weight of all monomers used in the production of (meth)acrylic resin. In addition, (meth)acrylic resin may be manufactured, for example, by a method of advancing polymerization using active energy rays such as ultraviolet rays.

As a polymerization initiator, a thermal polymerization initiator, a light polymerization initiator, etc. are used. Examples of the photopolymerization initiator include 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone. As a thermal polymerization initiator, for example, 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'- Azo compounds such as azobis(2-methylpropionate) and 2,2'-azobis(2-hydroxymethylpropionitrile); Lauryl peroxide, tert-butylhydroperoxide, benzoyl peroxide, tert-butylperoxybenzoate, cumene hydroperoxide, diisopropylperoxydicarbonate, dipropylperoxydicarbonate, tert-butylperoxy Organic peroxides such as neodecanoate, tert-butylperoxypivalate, and (3,5,5-trimethylhexanoyl)peroxide; Examples include inorganic peroxides such as potassium persulfate, ammonium persulfate, and hydrogen peroxide. Additionally, a redox-based initiator using a combination of peroxide and a reducing agent can also be used as a polymerization initiator.

As a method for producing (meth)acrylic resin, the solution polymerization method is preferable among the methods described above. An example of the solution polymerization method is to mix the monomers and organic solvent to be used, add a thermal polymerization initiator under a nitrogen atmosphere, and stir at about 40 to 90°C, preferably about 50 to 80°C, for about 3 to 15 hours. In order to control the reaction, the monomer or thermal polymerization initiator may be added continuously or intermittently during polymerization, or may be added while dissolved in an organic solvent. Examples of organic solvents include aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; Aliphatic alcohols such as propyl alcohol and isopropyl alcohol; Ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone can be used.

[2] Isocyanate-based crosslinking agent (B)

The adhesive composition further contains an isocyanate-based crosslinking agent (B). This isocyanate-based crosslinking agent (B) has two or more isocyanate groups in the molecule, and at least one isocyanate group is bonded to a carbon atom constituting the aliphatic skeleton. By using this isocyanate-based crosslinking agent (B) as a crosslinking agent, the adhesion between the adhesive layer and the optical member and the durability of the adhesive layer can be improved.

The aliphatic skeleton refers to a skeleton other than an aromatic ring, and includes, for example, an alicyclic structure in addition to chain or branched hydrocarbon groups. The isocyanate-based crosslinking agent (B) may contain an aromatic ring as long as it has an isocyanate group bonded to a carbon atom constituting the aliphatic skeleton.

A suitable example of the isocyanate-based crosslinking agent (B) is an isocyanate-based crosslinking agent in which an isocyanate group is bonded to the carbon atom of the methylene group constituting the aliphatic skeleton.

The number of methylene groups constituting the aliphatic skeleton, that is, the number of carbon atoms constituting the aliphatic skeleton is usually 1 to 15, preferably 1 to 10.

A specific example of the isocyanate-based crosslinking agent (B) is an aliphatic isocyanate-based crosslinking agent composed of an aliphatic skeleton and containing no aromatic ring. Examples of aliphatic isocyanate-based crosslinking agents include 1,6-hexamethylene diisocyanate, 1,4-tetramethylene diisocyanate, 2-methyl-1,5-pentane diisocyanate, 3-methyl-1,5-pentane diisocyanate, Includes lysine diisocyanate, isophorone diisocyanate, cyclohexyl diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated tetramethylxylene diisocyanate, etc.

Another specific example of the isocyanate-based crosslinking agent (B) is an isocyanate-based crosslinking agent that has an isocyanate group bonded to a carbon atom constituting the aliphatic skeleton and contains an aromatic ring. Examples of such isocyanate-based crosslinking agents include xylylene diisocyanate and the like.

Among them, an aliphatic isocyanate-based crosslinking agent composed of an aliphatic skeleton and containing no aromatic ring is advantageous in further improving the adhesion between the adhesive layer and the optical member.

In addition, the isocyanate-based crosslinking agent (B) is a polyhydric alcohol compound adduct of the above isocyanate compound (e.g., an adduct of trimethylolpropane), an isocyanurate, a biuret-type compound, and further polyether polyol or polyester polyol, It includes derivatives such as urethane-free polymer type isocyanate compounds obtained by addition reaction with acrylic polyol, polybutadiene polyol, polyisoprene polyol, etc. The isocyanate-based crosslinking agent (B) may be used individually or in combination of two or more types.

The content of the isocyanate-based crosslinking agent (B) is 0.1 to 1 part by weight, preferably 0.2 to 0.9 parts by weight, based on 100 parts by weight of the (meth)acrylic resin (A). If the content of the isocyanate-based crosslinking agent (B) is less than 0.1 part by weight, the adhesion between the adhesive layer and the optical member becomes insufficient, depending on the material of the surface of the optical member on which the adhesive layer is laminated. Additionally, depending on the material of the surface of the optical member on which the adhesive layer is laminated, durability when the adhesive layer is bonded to the optical member decreases. If the content of the isocyanate-based crosslinking agent (B) exceeds 1 part by weight, the adhesion between the adhesive layer and the optical member becomes insufficient even if sufficient curing time is used. Additionally, durability, especially heat resistance, decreases when the adhesive layer is bonded to an optical member.

[3] Ionic compound (C)

The adhesive composition may further contain an ionic compound (C) as an antistatic agent for imparting antistatic properties to the adhesive layer. The ionic compound (C) is a compound having an inorganic cation or organic cation and an inorganic anion or organic anion. Two or more types of ionic compounds (C) may be used.

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

Examples of organic cations include imidazolium cation, pyridinium cation, pyrrolidinium cation, ammonium cation, sulfonium cation, and phosphonium cation.

Among the above-described cationic components, organic cationic components are preferably used because they have excellent compatibility with the adhesive composition. Among organic cation components, pyridinium cation and imidazolium cation are particularly preferably used from the viewpoint of being difficult to charge when peeling off the release film provided on the adhesive layer.

Inorganic anions include, for example, chloride anion [Cl ^- ], bromide anion [Br ^- ], iodide anion [I ^- ], tetrachloroaluminate anion [AlCl ₄ ^- ], and heptachlorodialluminate anion [Al ₂ Cl. ₇ ^- ], tetrafluoroborate anion [BF ₄ ^- ], hexafluorophosphate anion [PF ₆ ^- ], perchlorate anion [ClO ₄ ^- ], nitrate anion [NO ₃ ^- ], hexafluoroacetic anion [ AsF ₆ ^- ], hexafluoroantimonate anion [SbF ₆ ^- ], hexafluoroniobate anion [NbF ₆ ^- ], hexafluorotantalate anion [TaF ₆ ^- ], dicyanamide anion [(CN) ₂ N ^- 〕 etc. may be mentioned.

Organic anions include, for example, acetate anion [CH ₃ COO ^- ], trifluoroacetate anion [CF ₃ COO ^- ], methane sulfonate anion [CH ₃ SO ₃ ^- ], trifluoromethane sulfonate anion [CF ₃ SO ₃ ^- ], p-toluenesulfonate anion [p-CH ₃ C ₆ H ₄ SO ₃ ^- ], bis(fluorosulfonyl)imide anion [(FSO ₂ ) ₂ N ^- ], bis(trifluoromethane Sulfonyl)imide anion [(CF ₃ SO ₂ ) ₂ N ^- ], tris (trifluoromethanesulfonyl) methanide anion [(CF ₃ SO ₂ ) ₃ C ^- ], dimethylphosphinate anion [(CH ₃ ) ₂ POO ^- ], (poly) hydrofluorofluoride anion [F(HF) _n ^- ] (n is about 1 to 3), thiocyanate anion [SCN ^- ], perfluorobutane sulfonate anion [C ₄ F ₉ SO ₃ ^- ], bis(pentafluoroethanesulfonyl)imide anion [(C ₂ F ₅ SO ₂ ) ₂ N ^- ], perfluorobutanoate anion [C ₃ F ₇ COO ^- 〕, (trifluoromethanesulfonyl)(trifluoromethanecarbonyl)imide anion [(CF ₃ SO ₂ )(CF ₃ CO)N ^- ], perfluoropropane-1,3-disulfonate anion [ ^- O ₃ S(CF ₂ ) ₃ SO ₃ ^- ], carbonate anion [CO ₃ ^2- ], etc.

Among the anionic components described above, an anionic component containing a fluorine atom is preferably used because it provides an ionic compound (C) with excellent antistatic performance. Specifically, bis(fluorosulfonyl)imide anion, hexafluorophosphate anion, or bis(trifluoromethanesulfonyl)imide anion can be mentioned.

Specific examples of the ionic compound (C) can be appropriately selected from the combination of the above-mentioned cationic component and anionic component. Examples of ionic compounds (C) having organic cations are classified according to the structure of the organic cation and are listed as follows.

Pyridinium salt:

N-hexylpyridinium hexafluorophosphate,

N-octylpyridinium hexafluorophosphate,

N-octyl-4-methylpyridinium hexafluorophosphate,

N-butyl-4-methylpyridinium hexafluorophosphate,

N-decylpyridinium bis(fluorosulfonyl)imide,

N-dodecylpyridinium bis(fluorosulfonyl)imide,

N-Tetradecylpyridinium bis(fluorosulfonyl)imide,

N-hexadecylpyridinium bis(fluorosulfonyl)imide,

N-dodecyl-4-methylpyridinium bis(fluorosulfonyl)imide,

N-Tetradecyl-4-methylpyridinium bis(fluorosulfonyl)imide,

N-hexadecyl-4-methylpyridinium bis(fluorosulfonyl)imide,

N-benzyl-2-methylpyridinium bis(fluorosulfonyl)imide,

N-benzyl-4-methylpyridinium bis(fluorosulfonyl)imide,

N-hexylpyridinium bis(trifluoromethanesulfonyl)imide,

N-octylpyridinium bis(trifluoromethanesulfonyl)imide,

N-octyl-4-methylpyridinium bis(trifluoromethanesulfonyl)imide,

N-Butyl-4-methylpyridinium bis(trifluoromethanesulfonyl)imide.

Imidazolium salt:

1-ethyl-3-methylimidazolium hexafluorophosphate,

1-ethyl-3-methylimidazolium p-toluenesulfonate,

1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide,

1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide,

1-Butyl-3-methylimidazolium methanesulfonate,

1-Butyl-3-methylimidazolium bis(fluorosulfonyl)imide.

Pyrrolidinium salt:

N-butyl-N-methylpyrrolidinium hexafluorophosphate,

N-butyl-N-methylpyrrolidinium bis(fluorosulfonyl)imide,

N-Butyl-N-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide.

Quaternary ammonium salts:

Tetrabutylammonium hexafluorophosphate,

Tetrabutylammonium p-toluenesulfonate,

(2-hydroxyethyl)trimethylammonium bis(trifluoromethanesulfonyl)imide,

(2-Hydroxyethyl)trimethylammonium dimethylphosphinate.

Additionally, examples of ionic compounds (C) having an inorganic cation include the following.

lithium bromide,

lithium iodide,

lithium tetrafluoroborate,

lithium hexafluorophosphate,

lithium thiocyanate,

lithium perchlorate,

lithium trifluoromethane sulfonate,

Lithium bis(fluorosulfonyl)imide

lithium bis(trifluoromethanesulfonyl)imide,

lithium bis(pentafluoroethanesulfonyl)imide,

Lithium tris(trifluoromethanesulfonyl)methanide,

lithium p-toluenesulfonate,

sodium hexafluorophosphate,

sodium bis(fluorosulfonyl)imide,

sodium bis(trifluoromethanesulfonyl)imide,

sodium p-toluenesulfonate,

potassium hexafluorophosphate,

potassium bis(fluorosulfonyl)imide,

potassium bis(trifluoromethanesulfonyl)imide,

Potassium p-toluenesulfonate.

The ionic compound (C) is preferably solid at room temperature. Compared to the case of using an ionic compound (C) that is liquid at room temperature, antistatic performance can be maintained for a long period of time. From the viewpoint of long-term stability of this antistatic property, the ionic compound (C) preferably has a melting point of 30°C or higher, and further, 35°C or higher. On the other hand, if the melting point is too high, compatibility with the (meth)acrylic resin (A) deteriorates, 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 content of the ionic compound (C) in the adhesive composition is preferably 0.2 to 8 parts by weight, more preferably 0.2 to 5 parts by weight, based on 100 parts by weight of the (meth)acrylic resin (A), More preferably, it is 0.3 to 5 parts by weight, and particularly preferably, it is 0.5 to 3 parts by weight. A content of 0.2 parts by weight or more of the ionic compound (C) is advantageous for improving antistatic performance, and a content of 8 parts by weight or less is advantageous for maintaining the durability of the adhesive layer.

[4] Silane compound (D)

The adhesive composition may further contain a silane compound (D). Accordingly, the adhesion between the adhesive layer and an optical member such as a glass substrate can be improved.

Silane compounds (D) include, for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris(2-methoxyethoxy)silane, and N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane. , N-(2-aminoethyl)-3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3- Mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyldimethoxymethylsilane, 3-glycidoxypropylethoxydimethyl Silane, etc. can be mentioned. Two or more types of silane compounds may be used.

The silane compound (D) may be of a silicon oligomer type. When silicone oligomers are expressed in the form of (monomer) oligomers, for example, the following can be mentioned.

3-mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer,

3-Mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer,

3-mercaptopropyltriethoxysilane-tetramethoxysilane copolymer,

copolymers containing a mercaptopropyl group such as 3-mercaptopropyltriethoxysilane-tetraethoxysilane copolymer;

mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer,

Mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer,

mercaptomethyltriethoxysilane-tetramethoxysilane copolymer,

copolymers containing a mercaptomethyl group such as mercaptomethyltriethoxysilane-tetraethoxysilane copolymer;

3-glycidoxypropyltrimethoxysilane-tetramethoxysilane copolymer,

3-glycidoxypropyltrimethoxysilane-tetraethoxysilane copolymer,

3-glycidoxypropyltriethoxysilane-tetramethoxysilane copolymer,

3-glycidoxypropyltriethoxysilane-tetraethoxysilane copolymer,

3-glycidoxypropylmethyldimethoxysilane-tetramethoxysilane copolymer,

3-glycidoxypropylmethyldimethoxysilane-tetraethoxysilane copolymer,

3-Glycidoxypropylmethyldiethoxysilane-tetramethoxysilane copolymer,

Copolymers containing a 3-glycidoxypropyl group such as 3-glycidoxypropylmethyldiethoxysilane-tetraethoxysilane copolymer;

3-methacryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer,

3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer,

3-methacryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer,

3-methacryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer,

3-methacryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer,

3-methacryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer,

3-methacryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer,

Copolymers containing a methacryloyloxypropyl group such as 3-methacryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymer;

3-acryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer,

3-acryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer,

3-acryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer,

3-acryloyloxypropyltriethoxysilane-tetraethoxysilane copolymer,

3-acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer,

3-acryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer,

3-acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer,

Copolymers containing acryloyloxypropyl groups such as 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane copolymer;

Vinyltrimethoxysilane-tetramethoxysilane copolymer,

Vinyltrimethoxysilane-tetraethoxysilane copolymer,

Vinyltriethoxysilane-tetramethoxysilane copolymer,

Vinyltriethoxysilane-tetraethoxysilane copolymer,

Vinylmethyldimethoxysilane-tetramethoxysilane copolymer,

Vinylmethyldimethoxysilane-tetraethoxysilane copolymer,

Vinylmethyldiethoxysilane-tetramethoxysilane copolymer,

Vinyl group-containing copolymers such as vinylmethyldiethoxysilane-tetraethoxysilane copolymer;

3-Aminopropyltrimethoxysilane-tetramethoxysilane copolymer,

3-Aminopropyltrimethoxysilane-tetraethoxysilane copolymer,

3-Aminopropyltriethoxysilane-tetramethoxysilane copolymer,

3-Aminopropyltriethoxysilane-tetraethoxysilane copolymer,

3-Aminopropylmethyldimethoxysilane-tetramethoxysilane copolymer,

3-Aminopropylmethyldimethoxysilane-tetraethoxysilane copolymer,

3-Aminopropylmethyldiethoxysilane-tetramethoxysilane copolymer,

Copolymers containing amino groups such as 3-aminopropylmethyldiethoxysilane-tetraethoxysilane copolymer, etc.

Most of the silane compounds (D) exemplified above are liquids. The content of the silane compound (D) in the adhesive composition is usually 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, more preferably 0.05 to 5 parts by weight, based on 100 parts by weight of the (meth)acrylic resin (A). It is 0.2 to 0.4 parts by weight. When the content of the silane compound (D) is 0.01 part by weight or more, it is easy to obtain the effect of improving adhesion between the adhesive layer and optical members such as a glass substrate. Moreover, if the content is 10 parts by weight or less, bleed-out of the silane compound (D) from the adhesive layer can be suppressed.

[5] Other ingredients

The adhesive composition may contain additives such as crosslinking catalysts, weathering stabilizers, tackifiers, plasticizers, softeners, dyes, pigments, inorganic fillers, light-scattering fine particles, and resins other than (meth)acrylic resin (A). . In addition, it is also useful to form a pressure-sensitive adhesive layer by mixing an ultraviolet curable compound in the pressure-sensitive adhesive composition and then curing the pressure-sensitive adhesive layer by irradiating it with ultraviolet rays to form a harder pressure-sensitive adhesive layer. Examples of crosslinking catalysts include amine-based compounds such as hexamethylenediamine, ethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethylenetetramine, isophoronediamine, trimethylenediamine, polyamino resin, and melamine resin. can be mentioned.

<Adhesive layer>

The adhesive layer according to the present invention contains the adhesive composition according to the present invention described above, and typically consists of the adhesive composition according to the present invention. The pressure-sensitive adhesive layer can be obtained by dissolving or dispersing each component of the pressure-sensitive adhesive composition in a solvent to form a solvent-containing pressure-sensitive adhesive composition, which is then applied onto a base film and dried. The adhesive layer according to the present invention is excellent in adhesion and durability.

The base film is generally a plastic film, and a typical example thereof is a release film (separator) to which a mold release treatment has been performed. The release film may be a film made of various resins such as polyethylene terephthalate, polybutylene terephthalate, polycarbonate, and polyalate, and the surface on which the adhesive layer is formed may be subjected to release treatment such as silicone treatment. . For example, an adhesive composition can be applied directly to the release-treated surface of a release film to form an adhesive layer, and the adhesive layer with the release film is laminated on an optical member to obtain an optical member with an adhesive layer. Alternatively, the adhesive composition may be applied directly to the surface of the optical member to form an adhesive layer, and if necessary, a release film may be laminated on the outer surface of the adhesive layer to form an optical member with an adhesive layer. When installing an adhesive layer on the surface of an optical member, it is preferable to perform surface activation treatment, such as plasma treatment, corona treatment, etc., on the bonding surface of the optical member and/or the bonding surface of the adhesive layer, and it is more preferable to perform corona treatment. desirable.

The thickness of the adhesive layer is preferably 10 to 45 μm, more preferably 10 to 30 μm, and still more preferably 10 to 20 μm. If the thickness of the adhesive layer is within this range, the adhesion between the adhesive layer and the optical member and durability when the adhesive layer is bonded to the optical member are advantageous. For the same reason, the adhesive layer preferably has a gel fraction in the range of 30 to 85%.

<Optical member with adhesive layer>

The adhesive layer according to the present invention can be suitably used as an adhesive layer for bonding members to each other, especially optical members. The optical member with an adhesive layer according to the present invention may be, for example, one in which an adhesive layer is laminated on a certain optical member, or another optical member may be laminated and bonded to the outer surface of the adhesive layer.

[1] First embodiment

One preferred embodiment of the optical member with an adhesive layer according to the present invention includes a resin film as an optical member and an adhesive layer laminated on at least one surface thereof. Resin films include surface protection films (protection films) that are bonded to optical films such as polarizers, protective films, and retardation films, and to optical films that are protected, and are used to protect the surface from scratches and contamination.

A polarizer is a film that has the function of extracting linearly polarized light from incident natural light. A suitable example is a uniaxially stretched polyvinyl alcohol-based resin film in which a dichroic dye such as iodine or a dichroic dye is adsorbed and oriented. The thickness of the polarizer is not particularly limited, but is usually 0.5 to 35 μm.

The protective film is a resin having light transmission (preferably optically transparent), such as a polyolefin-based resin such as chain polyolefin-based resin (polypropylene-based resin, etc.), cyclic polyolefin-based resin (norbornene-based resin, etc.); Cellulose-based resins such as triacetylcellulose and diacetylcellulose; polyester resin; polycarbonate-based resin; (meth)acrylic resin; polystyrene-based resin; polyetheretherketone resin; It may be a film made of a thermoplastic resin such as polysulfone resin.

Examples of the linear polyolefin resin include homopolymers of linear olefins such as polyethylene resin and polypropylene resin, as well as copolymers of two or more types of linear olefins.

Cyclic polyolefin-based resin is a general term for resins polymerized using cyclic olefin as a polymerization unit. Specific examples of cyclic polyolefin resins include ring-opening (co)polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins and chain olefins such as ethylene and propylene (typically random copolymers), and unsaturated polymers thereof. These include graft polymers modified with carboxylic acids or their derivatives, and their hydrides. Among them, norbornene-based resins using norbornene-based monomers such as norbornene and polycyclic norbornene-based monomers as cyclic olefins are preferably used.

Cellulose-based resin is a partially or fully esterified product of cellulose, and examples include acetic acid ester, propionic acid ester, butyric acid ester of cellulose, and mixed esters thereof. Among them, triacetylcellulose, diacetylcellulose, cellulose acetate propionate, cellulose acetate butyrate, etc. are preferably used.

Polyester resin is a resin other than the above cellulose resin that has an ester bond, and is generally composed of a polycondensate of a polyhydric carboxylic acid or a derivative thereof and a polyhydric alcohol. As the polyhydric carboxylic acid or its derivative, dicarboxylic acid or its derivative can be used, and examples include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalene dicarboxylic acid. As the polyhydric alcohol, diol can be used, and examples include ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol.

Specific examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethyl terephthalate, and polycyclohexane. Contains dimethylnaphthalate.

Polycarbonate-based resin is made of a polymer in which monomer units are bonded through carbonate groups. The polycarbonate-based resin may be a resin called modified polycarbonate, which has a polymer skeleton modified, or a copolymerized polycarbonate.

The (meth)acrylic resin may be a polymer containing methacrylic acid ester as the main monomer, and is preferably a copolymer in which a small amount of other comonomer components are copolymerized. The (meth)acrylic resin is more preferably a copolymer of methyl methacrylate and methyl acrylate, and may be further copolymerized with a third monofunctional monomer.

Examples of the third monofunctional monomer include ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxy methacrylate. Methacrylic acid esters other than methyl methacrylate, such as ethyl; Acrylic acid esters such as ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate; Hydroxyalkyl acrylic acid esters such as 2-(hydroxymethyl)methyl acrylate, 2-(1-hydroxyethyl)methyl acrylate, 2-(hydroxymethyl)ethyl acrylate, and 2-(hydroxymethyl)butyl acrylate; Unsaturated acids such as methacrylic acid and acrylic acid; Halogenated styrenes such as chlorostyrene and bromostyrene; Substituted styrenes such as vinyl toluene and α-methylstyrene; Unsaturated nitriles such as acrylonitrile and methacrylonitrile; Unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride; Examples include unsaturated imides such as phenylmaleimide and cyclohexylmaleimide. As for the third monofunctional monomer, only one type may be used individually, or two or more types may be used in combination.

(meth)acrylic resin may be further copolymerized with a polyfunctional monomer. Examples of multifunctional monomers include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, and nonaethylene glycol di(meth)acrylate. (meth)acrylate, tetradecaethylene glycol di(meth)acrylate, where both terminal hydroxyl groups of ethylene glycol or its oligomer are esterified with acrylic acid or methacrylic acid; A product obtained by esterifying both terminal hydroxyl groups of propylene glycol or its oligomer with acrylic acid or methacrylic acid; products obtained by esterifying the hydroxyl group of a dihydric alcohol such as neopentyl glycol di(meth)acrylate, hexanediol di(meth)acrylate, and butanediol di(meth)acrylate with acrylic acid or methacrylic acid; Bisphenol A, alkylene oxide adducts of bisphenol A, or halogen-substituted products thereof obtained by esterifying both terminal hydroxyl groups with acrylic acid or methacrylic acid; Those obtained by esterifying polyhydric alcohols such as trimethylolpropane and pentaerythritol with acrylic acid or methacrylic acid, and those obtained by ring-opening addition of the epoxy groups of glycidyl acrylate or glycidyl methacrylate to these terminal hydroxyl groups; Ring-opening addition of the epoxy group of glycidyl acrylate or glycidyl methacrylate to dibasic acids such as succinic acid, adipic acid, terephthalic acid, phthalic acid, and halogen-substituted products thereof, and alkylene oxide adducts thereof; Aryl (meth)acrylate; Aromatic divinyl compounds such as divinylbenzene, etc. can be mentioned. Among them, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and neopentyl glycol dimethacrylate are preferably used.

The (meth)acrylic resin may also be modified by performing a reaction between the functional groups of the copolymer. The reaction includes, for example, a demethanol condensation reaction within the polymer chain between the methyl ester group of methyl acrylate and the hydroxyl group of 2-(hydroxymethyl)methyl acrylate, and the demethanol condensation reaction between the carboxyl group of acrylic acid and the hydroxyl group of 2-(hydroxymethyl)methyl acrylate. Examples include dehydration condensation reaction within the polymer chain. Additionally, the (meth)acrylic resin may have any of a glutarimide derivative, a glutaric anhydride derivative, or a lactone ring structure.

(meth)acrylic resin may contain additives as needed. Examples of additives include lubricants, anti-blocking agents, heat stabilizers, antioxidants, antistatic agents, anti-glare agents, impact resistance improvers, and surfactants.

The (meth)acrylic resin may contain acrylic rubber particles from the viewpoint of film forming properties on the film and impact resistance of the film. Acrylic rubber particles are particles containing an elastic polymer mainly composed of acrylic acid ester as an essential component, and include those having a single-layer structure substantially composed only of this elastic polymer, and those having a multi-layer structure with this elastic polymer as one layer. An example of this elastic polymer is a crosslinked elastic copolymer made by copolymerizing alkyl acrylate as a main component with other copolymerizable vinyl monomers and crosslinkable monomers. Examples of alkyl acrylate, which is the main component of the elastic polymer, include those with an alkyl group having about 1 to 8 carbon atoms, such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and especially acrylic acid having an alkyl group with 4 or more carbon atoms. This is preferably used. Examples of other vinyl monomers copolymerizable with alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, and more specifically, methacrylic acid esters such as methyl methacrylate and styrene. Aromatic vinyl compounds, vinyl cyan compounds such as acrylonitrile, etc. can be mentioned. Examples of crosslinkable monomers include crosslinkable compounds having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, and Examples include (meth)acrylates of polyhydric alcohols, alkenyl esters of (meth)acrylic acid such as allyl (meth)acrylate, and divinylbenzene.

A laminate of a film made of a (meth)acrylic resin containing no rubber particles and a film made of a (meth)acrylic resin containing rubber particles can be used as a protective film.

The retardation film is an optical film that exhibits optical anisotropy, and in addition to the resins that can be used in the protective film, for example, polyvinyl alcohol-based resin, polyarylate-based resin, polyimide-based resin, polyether sulfone-based resin, and polyvinylidene fluoride. It may be a stretched film obtained by stretching a resin film made of ride/polymethyl methacrylate-based resin, liquid crystal polyester-based resin, saponified ethylene-vinyl acetate copolymer, polyvinyl chloride-based resin, etc. by about 1.01 to 6 times. Among them, a stretched film obtained by uniaxially stretching or biaxially stretching a polycarbonate-based resin film, cycloolefin-based resin film, (meth)acrylic-based resin film, or cellulose-based resin film is preferable. In addition, in this specification, a zero retardation film is also included in the retardation film (however, it can also be used as a protective film). In addition, films called uniaxial retardation films, wide viewing angle retardation films, low light modulus retardation films, etc. can also be applied as retardation films.

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

The in-plane retardation value R _e and the thickness direction retardation value R _th are each expressed by the following equations:

R _e =(n _x -n _y )×d

R _th =〔(n _x +n _y )/2-n _z 〕×d

It is defined as In the _{formula , n} It is the refractive index in the direction (z-axis direction perpendicular to the film plane), and d is the thickness of the film.

For the zero retardation film, for example, a resin film made of polyolefin resin such as cellulose resin, linear polyolefin resin, and cyclic polyolefin resin, polyethylene terephthalate resin, or (meth)acrylic resin can be used. In particular, cellulose-based resin, polyolefin-based resin, or (meth)acrylic-based resin is preferably used because it is easy to control the phase difference value and is easy to obtain. For example, a retardation film may be obtained by laminating a (meth)acrylic resin on one side or both sides of a retardation expression layer made of a resin different from the (meth)acrylic resin.

In addition, a film that exhibits optical anisotropy by application and orientation of a liquid crystalline compound or a film that exhibits optical anisotropy by application of an inorganic layered compound can also be used as a retardation film. These retardation films include what is called a temperature-compensated retardation film, as well as a film with obliquely oriented rod-shaped liquid crystals sold under the trade name “NH film” by JX Nikko Nisseki Energy Co., Ltd., sold by Fujifilm Co., Ltd. A film with obliquely oriented disc-shaped liquid crystals sold under the trade name “WV Film”, a film with a fully biaxial orientation sold under the trade name “VAC Film” by Sumitomo Chemical Co., Ltd., also by Sumitomo Chemical Co., Ltd. ), there is a biaxially oriented film sold under the product name “new VAC film”.

On the other hand, the surface protection film is a film used for the purpose of protecting the surface of the protected object, such as an optical film, from scratches or contamination. For example, a polarizer, a protective film, a retardation film, and a light diffusion sheet are optical members for a liquid crystal display device. Various optical films, such as reflective sheets, are usually distributed with a surface protection film laminated on the surface (if it has an adhesive layer on one side, the side opposite to the adhesive layer). It is common for the surface protection film to be peeled and removed after bonding the optical film to a liquid crystal cell or the like.

Examples of the base material for the surface protection film include polyolefin resins such as polyethylene, polypropylene, and polymethylpentene; Fluorinated polyolefin resins such as polyvinyl fluoride, polyvinylidene fluoride, and polyethylene fluoride; polyester resins such as polyethylene naphthalate, polyethylene terephthalate, polybutylene terephthalate, and polyethylene terephthalate/isophthalate copolymer; polyamides such as nylon 6 and nylon 6,6; Vinyl polymers such as polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, polyvinyl alcohol, and vinylon; Cellulose-based resins such as triacetylcellulose, diacetylcellulose, and cellophane; (meth)acrylic resins such as polymethyl methacrylate, polyethyl methacrylate, ethyl polyacrylate, and butyl polyacrylate; Others include polystyrene, polycarbonate, polyarylate, and polyimide. The optical member with an adhesive layer according to the present invention in which the resin film is a surface protection film is one in which an adhesive layer is provided on this base material.

In the optical member with an adhesive layer according to the present embodiment, it is preferable to attach the above-described release film to the surface of the adhesive layer and provide temporary attachment and protection until use. The optical member with an adhesive layer according to the present embodiment to which the release film is adhered includes a method of forming an adhesive layer by applying an adhesive composition on the release film, further laminating a resin film on the obtained adhesive layer, and applying the adhesive composition on the resin film. It can be manufactured by applying to form an adhesive layer and attaching a release film to the adhesive surface.

[2] Second embodiment

Another preferred embodiment of the optical member with an adhesive layer according to the present invention includes a laminate of a resin film and an adhesive layer laminated on at least one surface thereof. The resin film laminate is preferably a laminate of optical films selected from optical films such as polarizers, protective films, and retardation films. A representative example of a laminate of optical films is a polarizing plate. Even in the optical member with an adhesive layer according to the present embodiment, it is preferable to attach a release film to the surface of the adhesive layer to provide temporary attachment and protection until use.

As a polarizing plate, a linear polarizer having the property of absorbing linearly polarized light having a vibration plane in any direction incident on the film plane and transmitting linearly polarized light having a vibration plane orthogonal thereto, a linear polarizer having a vibration plane in any direction incident on the film plane Examples include a polarizing separator having the property of reflecting polarized light and transmitting linearly polarized light with a vibration plane orthogonal thereto, and an elliptical polarizing plate in which a retardation film is laminated on a linear polarizing plate.

A linear polarizing plate generally has a configuration in which the protective film described above is bonded to one side or both sides of the polarizer described above. When a protective film is bonded to both surfaces of a polarizer, an adhesive layer can be formed on at least one surface of the protective film. When the protective film is bonded only to one side of the polarizer, an adhesive layer can be formed on the surface of the polarizer (the side to which the protective film is not bonded). An elliptical polarizer is a product in which a retardation film is laminated on a linear polarizer, and the linear polarizer generally has the same configuration as above. When laminating an adhesive layer on an elliptically polarizing plate, the adhesive layer is usually laminated on the retardation film side.

A specific example of an optical member with an adhesive layer in the case where the optical member is a polarizing plate will be described with reference to the drawings. In the example shown in FIG. 1, the protective film 3 having the surface treatment layer 2 is adhered to one side of the polarizer 1 from the side opposite to the surface treatment layer 2 to form the polarizing plate 10. Consists of. An adhesive layer 20 is provided on the surface of the polarizer 1 opposite to the protective film 3, thereby forming a polarizing plate with an adhesive layer (optical member with an adhesive layer) 25. This adhesive layer 20 can be bonded to the glass substrate 30 on the side opposite to the polarizing plate 5, but the glass substrate 30 will be described later.

The polarizing plate 25 with an adhesive layer shown in FIG. 2 is the same as that in FIG. 1 except that the polarizing plate 10 includes a second protective film 4 adhered to the other side of the polarizer 1. The adhesive layer 20 is laminated on the outer surface of the second protective film 4. The polarizing plate 25 with an adhesive layer shown in FIG. 3 is similar to FIG. 1 except that the polarizing plate 10 includes a retardation film 7 adhered to the other side of the polarizer 1 through an interlayer adhesive 8. same. The polarizing plate 25 with an adhesive layer shown in FIG. 4 except that the polarizing plate 10 includes a retardation film 7 adhered to the outer surface of the second protective film 4 through an interlayer adhesive 8. Same as 2. In the examples shown in FIGS. 3 and 4 , the adhesive layer 20 is adhered to the retardation film 7 .

The surface treatment layer 2 formed on the surface of the protective film 3 may be a hard coat layer, an anti-glare layer, an anti-reflection layer, or an anti-static layer. Among these, multiple layers may be installed. As in the example shown in FIGS. 3 and 4, when the polarizing plate 10 includes the retardation film 7, if it is a small or medium-sized liquid crystal display device, a 1/4 wave plate is used as a suitable example of the retardation film 7. An example can be given. In this case, it is generally arranged so that the absorption axis of the polarizer 1 and the slow axis of the retardation film 7 intersect at approximately 45 degrees, but depending on the characteristics of the liquid crystal cell, the angle may be shifted from 45 degrees to some extent. there is. On the other hand, in large liquid crystal display devices such as televisions, a phase difference film 7 having various phase difference values according to the characteristics of the liquid crystal cell is used for the purpose of compensating for the phase difference or viewing angle of the liquid crystal cell. In this case, it is generally arranged so that the absorption axis of the polarizer 1 and the slow axis of the retardation film 7 are substantially perpendicular or substantially parallel. When the retardation film 7 is composed of a quarter wave plate, a uniaxial or biaxial stretched film is suitably used. In addition, when the retardation film 7 is installed for the purpose of compensating the phase difference or viewing angle of the liquid crystal cell, in addition to the uniaxially or biaxially stretched film, the liquid crystal is formed on a film oriented in the thickness direction in addition to uniaxially or biaxially stretched, and a support film. A so-called optical compensation film, such as a film in which orientation is fixed by applying a phase difference expressing material, can also be used as the retardation film 7.

Although it is customary to use a general (meth)acrylic adhesive as the interlayer adhesive 8 in FIGS. 3 and 4, it is of course possible to form an adhesive layer according to the present invention. As in the aforementioned large-sized liquid crystal display device, in cases where the absorption axis of the polarizer 1 and the slow axis of the retardation film 7 are arranged to be substantially perpendicular or substantially parallel, an adhesive is used instead of the interlayer adhesive 8. You can also use it. Examples of the adhesive include a water-based adhesive that is composed of an aqueous solution or aqueous dispersion and develops adhesive force by evaporating water, which is a solvent, and an ultraviolet curable adhesive that exhibits adhesive force by curing by ultraviolet irradiation. Bonding of the polarizer 1 and the protective films 3 and 4 is also usually accomplished using an adhesive.

The optical member with an adhesive layer according to the present embodiment has good adhesion and durability between the adhesive layer and the optical member because the adhesive layer contains the adhesive composition according to the present invention. According to the present invention, even if the surface of the optical member to which the adhesive layer is bonded is a surface that is difficult to activate by conventional surface activation treatments such as corona treatment or plasma treatment, the adhesive layer and the optical member have good adhesion and durability. An optical member with an adhesive layer can be obtained. The surface that is difficult to be activated by surface activation treatment as used herein is, for example, a surface in which the contact angle change rate when corona treatment is performed is 40% or less, and even 30% or less. The contact angle change rate is usually 0.1% or more, and is preferably 0.5% or more.

The rate of change of contact angle is given by the following equation:

Contact angle change rate (%) = {(Contact angle before corona treatment - Contact angle after corona treatment)/Contact angle before corona treatment} × 100

It is defined as The contact angle after corona treatment is the contact angle when the surface is subjected to one corona treatment under the conditions of an output of 0.3 kW and a line speed of 10 m/min and then left for 24 hours in an environment with a temperature of 23°C and a relative humidity of 60%. . The contact angle is the contact angle with respect to water, and the unit is “°”.

The contact angle change rate when the corona treatment is performed varies depending on the constituent material of the surface of the optical member. Thermoplastic resins with a contact angle change rate of 40% or less include (meth)acrylic resins, cellulose resins, polyester resins, and polycarbonate resins. The surface of the optical member made of these thermoplastic resins may be the surface of an optical film such as a protective film or retardation film.

[3] Third embodiment

Another preferred embodiment of the optical member with an adhesive layer according to the present invention is one in which another optical member is laminated and bonded to the outer surface of the adhesive layer in the optical member with an adhesive layer according to the first or second embodiment. The other optical member is preferably a glass substrate, and FIGS. 1 to 4 show the polarizing plate with an adhesive layer according to the second embodiment being bonded to the glass substrate 30.

Examples of the glass substrate 30 include a glass substrate for a liquid crystal cell, anti-glare glass, and glass for sunglasses. Examples of materials for the glass substrate 30 include soda-lime glass, low-alkali glass, and alkali-free glass. Among these, it is preferable that the glass substrate is a glass substrate of a liquid crystal cell.

A liquid crystal cell is usually laminated with a polarizing plate on both sides through an adhesive layer. Among these polarizing plates, only the polarizing plate disposed on the front side (visible side) of the liquid crystal cell may be the polarizing plate with an adhesive layer according to the present invention, and the polarizing plate with an adhesive layer according to the present invention may be used on the back of the liquid crystal cell. Only the polarizing plate disposed on the side (backlight side) may be the polarizing plate with an adhesive layer according to the present invention, or both of these may be the polarizing plates with an adhesive layer according to the present invention. The driving method of the liquid crystal cell may be any conventionally known method. The polarizing plate disposed on the back side (backlight side) usually does not have the surface treatment layer 2. Various optical films known to be disposed on the back side of the liquid crystal cell, such as a brightness enhancing film, a light-collecting film, and a diffusion film, may be installed on the outer surface of the outer polarizing plate disposed on the back side.

Optical members with an adhesive layer, such as a polarizing plate with an adhesive layer, can be suitably used in a liquid crystal display device. Liquid crystal display devices include, for example, personal computers including notebook type, desktop type, PDA (Personal Digital Assistant), etc.; Various mobile devices such as smartphones and tablet-type terminals; television; Vehicle-mounted displays; Electronic Dictionary; digital camera; digital video camera; electronic desk calculator; It can be suitably used as a liquid crystal display device for watches or the like.

Example

Hereinafter, the present invention will be described in more detail by referring to Examples and Comparative Examples, but the present invention is not limited to these examples. Hereinafter, parts and percentages indicating usage or content are based on weight, unless otherwise specified.

<Preparation Examples 1 to 9: Preparation of (meth)acrylic resin for adhesive layer>

Into a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer, and a stirrer, a monomer mixture having the monomer composition shown in Table 1 (% by weight when the total amount of monomer is 100% by weight) and diluted with ethyl acetate is injected. , the air in the device was replaced with nitrogen gas to make it oxygen-free and the internal temperature was raised to 55°C. After that, the entire amount of a solution of azobisisobutyronitrile (polymerization initiator) in ethyl acetate was added. After adding the initiator, this temperature was maintained for 1 hour, and then ethyl acetate was continuously added into the reaction vessel while maintaining the internal temperature at 54 to 56°C. When the concentration of the (meth)acrylic resin reached 35% by weight, acetic acid was added. The addition of ethyl was stopped, and the temperature was maintained at this temperature until 12 hours had elapsed from the start of the addition of ethyl acetate. Finally, ethyl acetate was added to adjust the concentration of the (meth)acrylic resin to 20% by weight, and an ethyl acetate solution of the (meth)acrylic resin was prepared.

The weight average molecular weight (Mw) and glass transition temperature (Tg) of the obtained (meth)acrylic resin were measured. Mw is a total of 5 columns in the GPC device, including 4 “TSKgel XL” manufactured by Tosoh Co., Ltd. and 1 “Shodex GPC KF-802” manufactured by Showa Denko Co., Ltd. and sold by Shokotsu Sho Co., Ltd. The samples were arranged in series and measured by standard polystyrene conversion using tetrahydrofuran as an eluent under the conditions of sample concentration of 5 mg/mL, sample introduction amount of 100 μL, temperature of 40°C, and flow rate of 1 mL/min. Tg was measured using a differential scanning calorimeter (DSC) "EXSTAR DSC6000" manufactured by SI Nano Technology Co., Ltd. under the conditions of a measurement temperature range of -80 to 50°C and a temperature increase rate of 10°C/min under a nitrogen atmosphere. The monomer composition (% by weight) of the monomer mixture used, and the Mw and Tg of the obtained (meth)acrylic resin are listed in Table 1.

Abbreviated names in the “Monomer Composition” column of Table 1 refer to the following monomers.

BA: butyl acrylate,

EHA: 2-ethylhexyl acrylate;

MA: methyl acrylate;

AA: acrylic acid;

HEA: 2-hydroxyethyl acrylate.

<Examples 1 to 10, Comparative Examples 1 to 4>

(1) Preparation of adhesive composition

With respect to 100 parts by weight of solid content of the (meth)acrylic resin (A) obtained in the above production example, the crosslinking agent (B), ionic compound (C), and silane compound (D) shown in Table 2 are added in the amounts shown in Table 2 ( parts by weight) were mixed, and ethyl acetate was added so that the solid content concentration was 28% by weight to prepare a solution of the adhesive composition. The mixing amount of each compounding ingredient shown in Table 2 is the weight number of active ingredients contained therein when the product used contains a solvent or the like.

The details of each compounding component indicated by abbreviated names in Table 2 are as follows.

B1: Ethyl acetate solution of trimethylolpropane adduct of m-xylylene diisocyanate (solids concentration 75%), “Dakenate D-110N” obtained from Mitsui Chemicals Co., Ltd.,

B2: Isocyanurate form of hexamethylene diisocyanate, liquid containing approximately 100% active ingredient, “Colonate HXR” obtained from Nippon Polyurethane Co., Ltd.,

B3: Ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solids concentration 75%), “Colonate L” obtained from Nippon Polyurethane Co., Ltd.,

B4: Ethyl acetate solution of the isocyanurate form of tolylene diisocyanate (solid concentration 50%), “Takenate D-204N” obtained from Mitsui Chemicals Co., Ltd.,

C1: N-butyl-4-methylpyridinium hexafluorophosphate,

S1: 3-Glycidoxypropyltrimethoxysilane, “KBM403” obtained from Shin-Etsu Chemical Co., Ltd.

(2) Production of adhesive layer

After drying each adhesive composition prepared in (1) above, using an applicator, on the release treated surface of a release film made of polyethylene terephthalate film (“PLR-382051” obtained from Lintech Co., Ltd.) to which release treatment has been performed. It was applied to a thickness of 20 μm and dried at 100°C for 1 minute to produce an adhesive layer (adhesive sheet).

(3) Production of polarizer with adhesive layer

A polarizing plate was produced by bonding a protective film made of the thermoplastic resin shown in Table 3 to both sides of a 23-μm-thick polarizer in which iodine was adsorbed and oriented on a uniaxially stretched polyvinyl alcohol film using an adhesive. Next, the surface (adhesive layer side) opposite to the separator in the adhesive layer produced in (2) above is bonded to the outer surface of one protective film using a laminator, and then bonded to the outer surface of one protective film under the conditions of a temperature of 23°C and a relative humidity of 65%. After curing for 7 days, a polarizing plate with an adhesive layer was obtained.

The abbreviated names written in the “Protective Film” column of Table 3 mean the following thermoplastic resins.

AC: (meth)acrylic resin (contact angle change rate: 17.2% based on the above definition),

PE: polyester-based resin (contact angle change rate: 14.7% based on the above definition),

CE: Cellulose-based resin (contact angle change: 21.7% based on the above definition).

(4) Evaluation of durability

After peeling the separator from the polarizing plate with an adhesive layer prepared in (3) above, the adhesive layer surface was adhered to both sides of a glass substrate for a liquid crystal cell (“Eagle . The following three types of durability tests were conducted using this sample.

[Durability Test]

·Heat resistance test maintained for 500 hours under dry conditions at a temperature of 80℃,

·Moisture and heat resistance test maintained for 500 hours in an environment with a temperature of 60℃ and a relative humidity of 90%,

· Thermal shock resistance (HS) test in which the operation of holding for 30 minutes under dry conditions at a temperature of 70°C, followed by holding for 30 minutes under dry conditions at a temperature of -40°C is one cycle, and repeats this for 200 cycles.

The samples after each test were visually observed, and durability was evaluated according to the following evaluation criteria. The results are listed in Table 3.

A: There are no visible changes in appearance such as lifting, peeling, or foaming.

B: There are almost no changes in appearance such as lifting, peeling, or foaming.

C: Many changes in appearance, such as lifting, peeling, and foaming, are observed.

D: Changes in appearance, such as lifting, peeling, and foaming, are significantly observed.

(5) Evaluation of adhesion between the protective film and the adhesive layer

A test piece of 25 mm in width x 150 mm in length was cut from the polarizing plate with an adhesive layer produced in (3) above. Next, after peeling the separator from this test piece, it was fixed to an adhesion evaluation jig manufactured by Nippon System Group Co., Ltd. and the following peeling test was performed. A test rubber piece [material: neoprene rubber, hardness: JIS A hardness 65] was applied to the surface of the adhesive layer, and the surface of the adhesive layer was rubbed with the rubber piece by moving the rubber piece back and forth 20 times on the test piece. The moving direction of the test rubber piece was parallel to the width direction of the test piece.

The surface of the adhesive layer side of the test piece after the peeling test was observed. In all of the examples and comparative examples, the adhesive layer was peeling off on one side in the width direction of the test piece after the peeling test, and a portion of the adhesive layer remained on the other end. The position of the remaining adhesive layer (position in the longitudinal direction of the test piece) was determined, and the distance from the one end to the position was measured as the peeling distance. The results are shown in Table 3. If the peeling distance (curing period of 7 days) is 15 mm or less, it can be said that the adhesion between the protective film and the adhesive layer is good.

1: Polarizer, 2: Surface treatment layer, 3, 4: Protective film, 7: Retardation film, 8: Interlayer adhesive, 10: Polarizing plate, 20: Adhesive layer, 25: Polarizing plate with adhesive layer, 30: Glass substrate.

Claims (11)

The content of structural units derived from a (meth)acrylic monomer having a hydroxyl group is 0.5 to 2% by weight, the content of structural units derived from a (meth)acrylic monomer having a carboxyl group is 3 to 4% by weight, and the glass transition temperature is - 100 parts by weight of (meth)acrylic resin (A) having a temperature of 40.0°C or higher,
0.1 to 1 part by weight of an isocyanate-based crosslinking agent (B) in which an isocyanate group is bonded to the carbon atom constituting the aliphatic skeleton
An adhesive composition containing. The adhesive composition according to claim 1, wherein the isocyanate group is bonded to a carbon atom constituting a methylene group. delete The adhesive composition according to claim 1 or 2, further comprising an ionic compound (C). The adhesive composition according to claim 1 or 2, further comprising a silane compound (D). An adhesive layer containing the adhesive composition according to claim 1 or 2. An optical member with an adhesive layer comprising an optical member and the adhesive layer according to claim 6 laminated thereon. The optical member with an adhesive layer according to claim 7, wherein the surface of the optical member on which the adhesive layer is laminated has a contact angle change rate of 40% or less when corona treatment is performed. The method of claim 8, wherein the optical member includes a polarizer and a protective film laminated thereon,
An optical member with an adhesive layer, wherein the surface is a surface of the protective film. The optical member with an adhesive layer according to claim 8, wherein the surface is a corona-treated surface. The optical member with an adhesive layer according to claim 9, wherein the surface is a corona-treated surface.

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