JP7541447B2 - CURABLE RESIN COMPOSITION FOR OPTICAL COMPONENTS, CURED PRODUCT THEREOF, POLARIZING PLATE, AND IMAGE DISPLAY DEVICE - Google Patents

Description

The present invention relates to a curable resin composition for optical components, a cured product thereof, a polarizing plate, and an image display device.

In recent years, flat displays such as liquid crystal displays, plasma displays, and organic electroluminescence displays have come into widespread use as display devices because they are space-saving and highly accurate. Of these, liquid crystal displays have attracted attention because they are more energy-efficient and highly accurate, and their development is underway.

In order to fulfill its function, a polarizing plate that acts as a light shutter is used in combination with liquid crystal in a liquid crystal display panel. A polarizing plate is an essential optical component for a liquid crystal display panel, and has a polarizer. Also, a circular polarizing plate may be used in an organic EL display to prevent reflection. A circular polarizing plate is an optical component that has a retardation plate with a specified phase difference and a polarizer. Polarizers are usually manufactured by uniaxially stretching polyvinyl alcohol (PVA) resin to 5 to 6 times its length in a water tank, and therefore have the disadvantage of being easily torn in the stretching direction and being brittle. For this reason, a protective film is attached to the front and/or back surface of the polarizer to form a polarizing plate.

Conventionally, cellulose-based resin films such as triacetyl cellulose films have been widely used as protective films for polarizers, i.e., polarizing plate protective films. In addition, since cellulose-based resin films have poor durability against water, the use of polyolefin-based resin films, acrylic-based resin films, polyester-based resin films, etc. has been considered as alternatives. However, these films require a film thickness of a certain value or more from the viewpoint of polarizing plate characteristics and handling suitability, making it difficult to make polarizing plates thinner and lighter. In addition, adhesives for bonding polarizing plate protective films to polarizers are also required to meet requirements specific to polarizing plate applications.

Therefore, in order to further reduce the thickness and weight of polarizing plates, the use of protective layers made of curable resin compositions as an alternative to protective films is being considered. In addition, the use of curable resin compositions as adhesives is also being considered in order to expand the range of options for polarizing plate protective films and further improve polarizing plate properties.

Patent Document 1 discloses a polarizing plate in which a first protective layer made of a cured product of a curable resin composition containing an active energy ray curable compound, a polarizer, an adhesive layer, and a second protective layer made of a thermoplastic resin film are laminated in this order. It is also disclosed that the polarizing plate is thin and lightweight, and has excellent durability. Paragraph "0042" of Patent Document 1 clearly states that, from the viewpoint of adhesion to the polarizer, it is preferable that the curable resin composition contains at least one epoxy compound. The curable resin composition used to form the protective layer, which is disclosed as a specific example, contains an epoxy compound, an oxetane compound, and a (meth)acrylic compound as active energy ray curable compounds. The curable resin composition used to form the adhesive layer, which is disclosed as a specific example, contains an epoxy compound and an oxetane compound as active energy ray curable compounds. From this, it can be seen that the curable resin composition according to this document is mainly characterized by containing an epoxy compound.

Patent Document 2 discloses a polarizing plate having a polarizer and a protective film disposed on the polarizer, the protective film being made of an ultraviolet-transmitting material and containing a cured product of a photopolymerizable compound and an ultraviolet absorber. It is also disclosed that the polarizer is protected from external moisture and ultraviolet light even when the member protecting the polarizer is made thin. In addition, paragraph "0013" of Patent Document 2 clearly states that acrylate is preferable as the photopolymerizable compound from the viewpoints of water vapor blocking properties, robustness, and light transmittance. All of the protective film compositions disclosed as specific examples also contain acrylate as the photopolymerizable compound. From this, it can be seen that the protective film composition (curable resin composition) containing the photopolymerizable compound according to this document is mainly characterized by containing acrylate.

Patent Document 3 discloses an adhesive containing a cyclopolymerizable monomer of a specific structure, which is used to manufacture a polarizing plate in which a transparent protective film is provided on at least one surface of a polarizer via an adhesive layer. In addition, paragraph "0007" of Patent Document 3 discloses that photocurable adhesives such as ultraviolet curable adhesives do not provide sufficient polarizing plate durability. Then, paragraphs "0009", "0014", "0190", etc. of Patent Document 3 disclose that the adhesive according to this document is an electron beam curable adhesive, which has excellent durability under harsh environments such as high humidity and high temperature. Specific examples include an adhesive composed of only one of the above cyclopolymerizable monomers, and an electron beam curable adhesive composed of a mixture of one of the above cyclopolymerizable monomers and acryloylmorpholine.

JP 2010-039299 A JP 2005-010329 A JP 2013-092771 A

However, the present inventors have found that, although the cured product of the curable resin composition mainly characterized by containing an epoxy compound as in Patent Document 1 has excellent adhesion to the polarizer, the polarizer cracks in the polarizing plate when the temperature changes. The present inventors have also found that the cured product of the curable resin composition mainly characterized by containing an acrylate as in Patent Document 2 has poor adhesion to the polarizer and has a large curing shrinkage, which causes the polarizer to crack and the polarizing plate to deform when the polarizing plate is produced. The present inventors have also found that the adhesive containing only a cyclopolymerizable monomer as in Patent Document 3 and the cured product of an adhesive consisting of a mixture of this and a compound having a (meth)acryloyl group such as acryloylmorpholine do not have sufficient mechanical strength. They have also found that the adhesion to the polarizer and the durability of the polarizing plate in a wide range of temperature and humidity environments are insufficient. Thus, with these curable resin compositions, in applications for optical components such as polarizing plates, there is a problem that at least one of the adhesion to the attached member such as a polarizer and the durability of the optical component is insufficient.

The present invention aims to provide a means for improving both the adhesion to a substrate and the durability of an optical component in a curable resin composition for use in optical components.

The above problems of the present invention can be solved by the following means.

The present invention comprises an epoxy compound (A) and a cyclopolymerizable monomer (B) represented by the following general formula (1) or the following general formula (2),
The curable resin composition for optical members, wherein the content of the cyclopolymerizable monomer (B) is 1 part by mass or more and 100 parts by mass or less based on 100 parts by mass of the epoxy compound (A).

(In the formula, each R is independently a hydrogen atom or a monovalent organic group,
X ¹ , Y ¹ , Z ¹ , X ² and Y ² each independently represent a methylene group, an oxygen atom, or an imino group;
At least one of X ¹ , Y ¹ , and Z ¹ is an oxygen atom or an imino group, and at least one of X ² and Y ² is an oxygen atom or an imino group.

The present invention makes it possible to provide a means for improving both the adhesion of a curable resin composition for use in optical components and its cured product to a substrate and the durability of the optical components.

FIG. 2 is a schematic diagram showing a method for bonding a film and a polarizer in the production of polarizing plates P1 to P13 in the examples. FIG. 2 is a schematic diagram showing a method for bonding a film and a polarizer in the production of polarizing plates P14 to P20 in the examples. FIG. 2 is a schematic diagram for explaining an evaluation method of a warm water immersion test in the examples. FIG. 4 is a schematic diagram for explaining an evaluation method for polarizer cracking in a thermal shock test in the examples.

The following describes a preferred embodiment of the present invention. Unless otherwise specified, the operation and physical properties are measured at room temperature (20°C to 25°C) and a relative humidity of 40% RH to 60% RH.

In this specification, "(meth)acrylate" is a general term for acrylate and methacrylate. Similarly, compounds containing (meth), such as (meth)acrylic acid, are a general term for compounds that have "meth" in their names and compounds that do not have "meth."

In addition, in this specification, "(co)polymer" is a general term for homopolymers and copolymers.

<Curable resin composition for optical members>
One embodiment of the present invention comprises an epoxy compound (A) and a cyclopolymerizable monomer (B) represented by the following general formula (1) or the following general formula (2),
The curable resin composition for optical members, wherein the content of the cyclopolymerizable monomer (B) is 1 part by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the epoxy compound (A).

(In the formula, each R is independently a hydrogen atom or a monovalent organic group,
X ¹ , Y ¹ , Z ¹ , X ² and Y ² each independently represent a methylene group, an oxygen atom, or an imino group;
At least one of X ¹ , Y ¹ , and Z ¹ is an oxygen atom or an imino group, and at least one of X ² and Y ² is an oxygen atom or an imino group.
In this specification, the term "curable resin composition" refers to a composition containing at least one compound that is polymerized and cured directly or via a polymerization initiator (also simply referred to as "curable compound" in this specification).

The inventors speculate that the mechanism by which the above configuration solves the problem is as follows.

A curable resin composition containing only an epoxy compound (A) as a curable compound has excellent adhesion to the adherend, but the optical components using this composition are vulnerable to temperature changes, and may be destroyed within the component when the temperature changes. On the other hand, a curable resin composition containing only a cyclopolymerizable monomer (B) as a curable compound does not have sufficient adhesive strength or durability. However, by using the epoxy compound (A) and the cyclopolymerizable monomer (B) in combination, and setting the content of the cyclopolymerizable monomer (B) to a predetermined range relative to the content of the epoxy compound (A), the adhesion of the cured product to the adherend is sufficient, and the durability of the optical component is improved. The details of the reason for this are unclear, but it is thought that within the range in which good adhesion is expressed by the epoxy compound (A), these cured products act to cancel out and enhance each other's changes caused by water and heat, resulting in a good balance.

Note that the above mechanism is based on speculation, and its accuracy does not affect the technical scope of the present invention.

Hereinafter, each component constituting the curable resin composition for optical members according to one embodiment of the present invention will be described in detail.

[Curable Compound]
The curable resin composition for optical members according to one embodiment of the present invention contains, as curable compounds, an epoxy compound (A) and a curable polymerizable monomer (B) having a specific structure.

(Epoxy compound (A))
In this specification, the epoxy compound refers to a compound having an epoxy group. The epoxy group is generally a cationic polymerizable functional group. The epoxy compound is generally a cationic polymerizable curable compound.

The epoxy compound (A) acts to improve the adhesion of the cured product of the curable resin composition for optical components to adherends such as polarizers, and also to improve the hardness of the cured product. In this way, the epoxy compound (A) acts to improve the adhesion to adherends and the durability of the optical components.

In this specification, a compound having a radically polymerizable functional group in addition to an epoxy group is not considered to be an epoxy compound (A).

The epoxy compound (A) is not particularly limited, and any known compound having an epoxy group can be used. Among these, from the viewpoints of adhesion to the adherend and durability of the optical component, alicyclic epoxy group-containing compounds, alicyclic group-containing epoxy group-containing compounds, and aromatic group-containing epoxy group-containing compounds are preferred.

The alicyclic epoxy group-containing compound refers to a compound having an alicyclic epoxy group in the molecule. The alicyclic epoxy group refers to a functional group having a structure in which two adjacent carbon atoms of an alicyclic (cycloalkyl) group constitute an epoxy group, as shown in the following general formula:
do.

The alicyclic epoxy resin-containing compound improves the curing reactivity of the curable resin composition for optical components. In addition, when the alicyclic epoxy group-containing compound has two or more epoxy groups in one molecule, it forms a crosslinked structure, so that the glass transition temperature and elastic modulus after curing are higher. In addition, the volume change due to heat is smaller, and the occurrence of internal stress, in other words, the decrease in strength, is more suppressed. As a result, the occurrence of cracking of the polarizing plate during a temperature change from a low temperature to a high temperature is more suppressed, and the durability of the optical components is further improved. In addition, the alicyclic group in the alicyclic epoxy group may be substituted with a methyl group, an ethyl group, or the like.

The alicyclic epoxy group-containing compound may have at least one alicyclic epoxy group in one molecule, but preferably has two or more alicyclic epoxy groups in one molecule.

Specific examples of alicyclic epoxy group-containing compounds include, but are not limited to, vinylcyclohexene monoxide, vinylcyclohexene dioxide, limonene dioxide, 1,2:8,9-diepoxylimonene, 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, 3,4-epoxycyclohexenylmethyl-3,4'-epoxycyclohexene carboxylate (also known as 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexane carboxylate), bis-(6-methyl-3,4-epoxycyclohexyl)adipate, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, etc. Among these, 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate is preferred from the viewpoints of curing reactivity, adhesion to the adherend, and durability of the optical member.

The alicyclic epoxy group-containing compound may be a synthetic product or a commercially available product. There is no particular limitation on the commercially available product, but an example of such a product is Celloxide (registered trademark) 2021P manufactured by Daicel Corporation.

The aromatic group-containing epoxy group-containing compound is a compound having an aromatic group and an epoxy group in the molecule, and is a compound other than the above-mentioned alicyclic epoxy group-containing compound (i.e., an epoxy compound having an aromatic group and not having an alicyclic epoxy group).

The aromatic group-containing epoxy group-containing compound may have at least one epoxy group in one molecule, but preferably has two or more epoxy groups in one molecule.

When an aromatic group-containing epoxy group-containing compound has only one epoxy group in one molecule, it is difficult to improve the viscosity of a curable resin composition for optical components. This makes it easier to eliminate air bubbles that occur when laminating a protective film in the manufacture of a polarizing plate. In this way, the aromatic group-containing epoxy group-containing compound further improves high-speed productivity of optical components, particularly in applications of adhesive compositions. In addition, when the aromatic group-containing epoxy group-containing compound has two or more epoxy groups in one molecule, it forms a crosslinked structure, so that the glass transition temperature and elastic modulus after curing are higher. In addition, the volume change due to heat is smaller, and the generation of internal stress, in other words, the decrease in strength, is further suppressed.

Examples of aromatic group-containing epoxy group-containing compounds include phenyl glycidyl ether, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, bisphenol AD diglycidyl ether, glycidyl ethers of 3,3',5,5'-tetramethyl-4,4'-biphenol, novolac resins (e.g., phenol novolac type epoxy resins, bisphenol A novolac type epoxy resins, cresol novolac type epoxy resins, etc.). resin, etc.), glycidyl ethers of phenol aralkyl resins, glycidyl ethers of naphthol aralkyl resins, glycidyl ethers of phenol dicyclopentadiene resins, glycidyl aminations of 1,3-phenylenediamine, glycidyl aminations of 1,4-phenylenediamine, glycidyl aminations and glycidyl ethers of 3-aminophenol, glycidyl aminations and glycidyl ethers of 4-aminophenol, etc. Among these, phenyl glycidyl ether and glycidyl ethers of novolac resins are preferred, and phenyl glycidyl ether and bisphenol A novolac type epoxy resin are more preferred, particularly from the viewpoint of high-speed productivity of optical members in the application of the adhesive composition.

The aromatic group-containing epoxy group-containing compound may be a synthetic product or a commercially available product. There is no particular limitation on the commercially available product, but examples include Denacol (registered trademark) EX-141 manufactured by Nagase ChemteX Corporation and jER (registered trademark) 157S70 manufactured by Mitsubishi Chemical Corporation.

The alicyclic group-containing epoxy group-containing compound is a compound having an alicyclic group and an epoxy group in the molecule, and is a compound other than the above-mentioned alicyclic epoxy group-containing compound and aromatic group-containing epoxy group-containing compound (i.e., an epoxy compound having an alicyclic group, but not having an alicyclic epoxy group or aromatic group).

The alicyclic group-containing epoxy group-containing compound may have at least one epoxy group in one molecule, but it is preferable that the compound has two or more epoxy groups in one molecule.

When the alicyclic group-containing epoxy group-containing compound has only one epoxy group in one molecule, it further improves the curing reactivity of the curable resin composition for optical members. In addition, the alicyclic group-containing epoxy group-containing compound further improves the viscosity and glass transition temperature of the curable resin composition for optical members. As a result, it becomes easier to adjust the film thickness in the use of the composition for forming a protective layer. In addition, when the alicyclic group-containing epoxy group-containing compound has two or more epoxy groups in one molecule, it forms a crosslinked structure, so that the glass transition temperature and elastic modulus after curing become higher. In addition, the volume change due to heat is smaller, and the generation of internal stress, in other words, the decrease in strength, is further suppressed.

In the alicyclic group-containing epoxy group-containing compound, the alicyclic group is not particularly limited, but is preferably a group consisting of an alicyclic hydrocarbon ring having 3 or more ring carbon atoms, more preferably a group consisting of an alicyclic hydrocarbon ring having 3 or more and 8 or less ring carbon atoms, and even more preferably a group consisting of cyclohexane.

Specific examples of the alicyclic group-containing epoxy group-containing compound include, but are not limited to, cyclohexanedimethanol diglycidyl ether, dicyclopentenyldialcohol diglycidyl ether, diglycidyl ether of hydrogenated bisphenol A, dihydroxyterpene diglycidyl ether, 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol, and the like. Among these, 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol is preferred from the viewpoint of ease of film thickness adjustment in applications of the protective layer-forming composition.

The alicyclic group-containing epoxy group-containing compound may be a synthetic product or a commercially available product. There is no particular limitation on commercially available products, but examples of such products include EHPE3150 and EHPE3150CE manufactured by Daicel Corporation.

The curable resin composition for optical members according to one embodiment of the present invention may contain, as the epoxy compound (A), an epoxy compound (other epoxy compound) other than the alicyclic epoxy group-containing compound, the alicyclic group-containing epoxy group-containing compound, and the aromatic group-containing epoxy group-containing compound.

The epoxy equivalent of the epoxy compound contained in epoxy compound (A) is not particularly limited, but is preferably 70 or more and 500 or less. The epoxy equivalent is more preferably 90 or more and 400 or less, and even more preferably 120 or more and 300 or less.

Epoxy compounds (A) can be used alone or in combination of two or more.

The epoxy compound preferably contains a polyfunctional epoxy compound having two or more epoxy groups in one molecule. By containing a polyfunctional epoxy compound, the glass transition temperature and elastic modulus after curing are higher. In addition, the volume change due to heat is smaller, and the generation of internal stress, in other words, the decrease in strength, is further suppressed. From the viewpoint of further improving such effects, the content (mixture amount) of the polyfunctional epoxy compound is preferably 50 parts by mass or more out of 100 parts by mass of the epoxy compound (A). In addition, the content of the polyfunctional epoxy compound is more preferably 80 parts by mass or more out of 100 parts by mass of the epoxy compound (A), and even more preferably 90 parts by mass or more, and the content of the polyfunctional epoxy compound is particularly preferably 100 parts by mass out of 100 parts by mass of the epoxy compound (A) (upper limit 100 parts by mass).

When the curable resin composition for optical members is used as an adhesive composition, the epoxy compound (A) preferably contains an alicyclic epoxy group-containing compound. In this case, the content (mixture amount) of the alicyclic epoxy group-containing compound is preferably 10 parts by mass or more out of 100 parts by mass of the epoxy compound (A). The content of the alicyclic epoxy group-containing compound is more preferably 30 parts by mass or more out of 100 parts by mass of the epoxy compound (A), and more preferably 40 parts by mass or more. On the other hand, the content of the alicyclic epoxy group-containing compound is preferably 100 parts by mass or less out of 100 parts by mass of the epoxy compound (A). The content of the alicyclic epoxy group-containing compound is more preferably 80 parts by mass or less out of 100 parts by mass of the epoxy compound (A), and more preferably 60 parts by mass or less. In this case, it is preferable to include an alicyclic group-containing epoxy group-containing compound or an aromatic group-containing epoxy group-containing compound as an epoxy compound other than the alicyclic epoxy group-containing compound, and it is more preferable to include an alicyclic group-containing epoxy group-containing compound.

When the curable resin composition for optical members is used as a composition for forming a protective layer, the epoxy compound (A) preferably contains an alicyclic epoxy group-containing compound. In this case, the content (mixture amount) of the alicyclic epoxy group-containing compound is preferably 10 parts by mass or more out of 100 parts by mass of the epoxy compound (A). In addition, the content of the alicyclic epoxy group-containing compound is more preferably 30 parts by mass or more out of 100 parts by mass of the epoxy compound (A), and more preferably 60 parts by mass or more. On the other hand, the content of the alicyclic epoxy group-containing compound is preferably 100 parts by mass or less out of 100 parts by mass of the epoxy compound (A). In addition, the content of the alicyclic epoxy group-containing compound is more preferably 90 parts by mass or less out of 100 parts by mass of the epoxy compound (A), and more preferably 80 parts by mass or less. In this case, it is preferable to include an alicyclic group-containing epoxy group-containing compound or an aromatic group-containing epoxy group-containing compound as an epoxy compound other than the alicyclic epoxy group-containing compound, and it is more preferable to include an alicyclic group-containing epoxy group-containing compound.

(Cyclopolymerizable monomer (B))
In this specification, the cyclopolymerizable monomer refers to a monomer in which carbon-carbon double bonds can form a ring structure within the molecule upon radical polymerization.

The cyclopolymerizable monomer (B) has a structure represented by the following general formula (1) or the following general formula (2).

(In the formula, each R is independently a hydrogen atom or a monovalent organic group,
X ¹ , Y ¹ , Z ¹ , X ² and Y ² each independently represent a methylene group, an oxygen atom, or an imino group;
At least one of X ¹ , Y ¹ , and Z ¹ is an oxygen atom or an imino group, and at least one of X ² and Y ² is an oxygen atom or an imino group.
In the above general formula (1), it is preferable that one of X ¹ , Y ¹ and Z ¹ is an oxygen atom, and it is more preferable that Y ¹ is an oxygen atom.

In the above general formula (2), it is preferable that one of ^X2 and ^Y2 is an oxygen atom, and it is more preferable that ^Y2 is an oxygen atom.

The cyclopolymerizable monomer (B) acts to improve the durability of the optical component by suppressing the occurrence of cracks in the polarizing plate when the temperature changes from low to high in the cured product of the curable resin composition for optical components.

In addition, since the cyclopolymerizable monomer (B) has a low glass transition temperature, it acts to reduce the viscosity of the curable resin composition for optical components. And, for example, the cyclopolymerizable monomer (B) acts to make it easier to eliminate air bubbles that are generated when laminating with a protective film in the production of a polarizing plate. In this way, the cyclopolymerizable monomer (B) can further increase the high-speed productivity of optical components, especially in applications of adhesive compositions.

Among these, from the viewpoints of durability of optical members and high-speed productivity of optical members in applications of adhesive compositions, it is preferable that the cyclopolymerizable monomer (B) is a monomer having a structure represented by the above general formula (1). It is more preferable that the cyclopolymerizable monomer (B) is a monomer represented by the following general formula (3).

(In the formula, ^R1 is the same as R in the above general formula (1).)
In the above general formula (1), (2) and (3), the monovalent organic group may be linear or branched, and may contain a cyclic structure.

In the above general formula (1), the above general formula (2), and the above general formula (3), the monovalent organic group is preferably an unsubstituted hydrocarbon group, a hydrocarbon group substituted with a halogen atom, a hydrocarbon group substituted with a cyano group, a hydrocarbon group substituted with a trimethylsilyl group, or a group consisting of a combination of one or more of these groups, each independently, and one or more ether groups.

Therefore, the cyclopolymerizable monomer (B) is more preferably an α-allyloxymethylacrylic acid monomer (hereinafter also simply referred to as an AMA monomer) represented by the above general formula (3), in which R ¹ is a hydrogen atom, or an unsubstituted hydrocarbon group, a hydrocarbon group substituted with a halogen atom, a hydrocarbon group substituted with a cyano group, a hydrocarbon group substituted with a trimethylsilyl group, or a group consisting of a combination of one or more of any one or more of these groups, each independently, and one or more ether groups.

AMA monomers, for example, undergo polymerization while cyclizing, as shown in the following formula, to form a main chain skeleton having a repeating unit of a five-membered ring ether structure with methylene groups on both sides.

(In the formula, R ¹ is the same as in the above general formula (3), and X represents an initiating radical or a propagating radical.)
Such a main skeleton structure improves the adhesiveness to the adherend and also acts to suppress the occurrence of damage to the optical member when the temperature changes from low to high, thereby improving the durability of the optical member.

In addition, as shown in the formula below, for example, AMA monomers can be partially polymerized without cyclization to form a main chain skeleton having a repeating unit of a five-membered ring ether structure with methylene groups on both sides, and some of the units having an allyl ether group in the side chain.

(In the formula, R ¹ is the same as in the above general formula (3), and X represents an initiating radical or a propagating radical.)
Such a main skeleton structure serves as a starting point for forming a crosslinked structure, and acts to further improve the durability of the optical member.

In the above general formula (1), the above general formula (2), and the above general formula (3), the hydrocarbon group in the monovalent organic group is not particularly limited. Examples of the hydrocarbon group include a chain-like saturated hydrocarbon group having 1 or more carbon atoms, a chain-like unsaturated hydrocarbon group having 2 or more carbon atoms, an alicyclic hydrocarbon group having 3 or more carbon atoms, and an aromatic hydrocarbon group having 6 or more carbon atoms. Among these, a chain-like saturated hydrocarbon group having 1 to 30 carbon atoms, a chain-like unsaturated hydrocarbon group having 3 to 30 carbon atoms, an alicyclic hydrocarbon group having 4 to 30 carbon atoms, and an aromatic hydrocarbon group having 6 to 30 carbon atoms are preferred.

In the above general formula (1), the above general formula (2), and the above general formula (3), examples of the halogen atom in the monovalent organic group include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.

The chain-like saturated hydrocarbon group is not particularly limited, but examples thereof include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-amyl, sec-amyl, tert-amyl, neopentyl, n-hexyl, sec-hexyl, n-heptyl, n-octyl, sec-octyl, tert-octyl, 2-ethylhexyl, capryl, nonyl, decyl, undecyl, lauryl, tridecyl, myristyl, pentadecyl, cetyl, heptadecyl, stearyl, nonadecyl, eicosyl, seryl, and melissyl groups.

The chain unsaturated hydrocarbon group is not particularly limited, but examples thereof include a crotyl group, a 1,1-dimethyl-2-propenyl group, a 2-methyl-butenyl group, a 3-methyl-2-butenyl group, a 3-methyl-3-butenyl group, a 2-methyl-3-butenyl group, an oleyl group, a linoleic group, and a linolene group.

Examples of alicyclic hydrocarbon groups include, but are not limited to, cyclopentyl, cyclopentylmethyl, cyclohexyl, cyclohexylmethyl, 4-methylcyclohexyl, 4-tert-butylcyclohexyl, tricyclodecanyl, isobornyl, adamantyl, dicyclopentanyl, and dicyclopentenyl.

Aromatic hydrocarbon groups are not particularly limited, but examples include phenyl groups, methylphenyl groups, dimethylphenyl groups, trimethylphenyl groups, 4-tert-butylphenyl groups, benzyl groups, diphenylmethyl groups, diphenylethyl groups, triphenylmethyl groups, cinnamyl groups, naphthyl groups, and anthranyl groups.

The group consisting of a combination of an ether group and a hydrocarbon group is not particularly limited, but examples thereof include chain ether groups such as a methoxyethyl group, a methoxyethoxyethyl group, a methoxyethoxyethoxyethyl group, a 3-methoxybutyl group, an ethoxyethyl group, and an ethoxyethoxyethyl group. In addition, examples thereof include groups having both an alicyclic hydrocarbon group, such as a cyclopentoxyethyl group, a cyclohexyloxyethyl group, a cyclopentoxyethoxyethyl group, a cyclohexyloxyethoxyethyl group, and a dicyclopentenyloxyethyl group, and a chain ether group. In addition, examples thereof include groups having both an aromatic hydrocarbon group, such as a phenoxyethyl group or a phenoxyethoxyethyl group, and a chain ether group. Other examples include cyclic ether groups such as a glycidyl group, a β-methylglycidyl group, a β-ethylglycidyl group, a 3,4-epoxycyclohexylmethyl group, a 2-oxetanemethyl group, a 3-methyl-3-oxetanemethyl group, a 3-ethyl-3-oxetanemethyl group, a tetrahydrofuranyl group, a tetrahydrofurfuryl group, a tetrahydropyranyl group, a dioxazolanyl group, and a dioxanyl group.

In the above general formula (1), the above general formula (2), and the above general formula (3), the hydrocarbon group in the monovalent organic group is preferably an unsubstituted hydrocarbon group. In addition, in the above general formula (1), the above general formula (2), and the above general formula (3), the hydrocarbon group in the monovalent organic group is more preferably an unsubstituted linear saturated hydrocarbon group having 1 or more carbon atoms. Furthermore, an unsubstituted linear saturated hydrocarbon group having 1 to 30 carbon atoms is even more preferable, and an unsubstituted linear saturated hydrocarbon group having 1 to 4 carbon atoms is particularly preferable. And, a methyl group is most preferable.

Therefore, in a particularly preferred embodiment of the present invention, the AMA monomer is represented by the above general formula (3), and R ¹ is a hydrogen atom or a chain-like saturated hydrocarbon group having 1 to 4 carbon atoms. That is, in a particularly preferred embodiment of the present invention, the AMA monomer is α-allyloxymethylacrylic acid, or an alkyl α-allyloxymethylacrylate in which the chain-like alkyl group has 1 to 4 carbon atoms. Also, in a most preferred embodiment of the present invention, the AMA monomer is represented by the above general formula (3), and R ¹ is a methyl group. That is, in a most preferred embodiment of the present invention, the AMA monomer is methyl α-allyloxymethylacrylate (also known as methyl-2-allyloxymethylacrylate). By using an AMA monomer having such a structure, the durability of the optical member and the high-speed productivity of the optical member in the application of the adhesive composition are significantly improved.

Specific examples of AMA monomers include, but are not limited to, α-allyloxymethylacrylic acid, methyl α-allyloxymethylacrylate, ethyl α-allyloxymethylacrylate, n-propyl α-allyloxymethylacrylate, isopropyl α-allyloxymethylacrylate, n-butyl α-allyloxymethylacrylate, sec-butyl α-allyloxymethylacrylate, tert-butyl α-allyloxymethylacrylate, n-amyl α-allyloxymethylacrylate, sec-amyl α-allyloxymethylacrylate, tert-amyl α-allyloxymethylacrylate, α-allyloxymethylacrylate, α-allyloxymethylacrylate, neopentyl, α-allyloxymethylacrylate, n-hexyl, α-allyloxymethylacrylate, sec-hexyl, α-allyloxymethylacrylate, n-heptyl, α-allyloxymethylacrylate, n-octyl, α-allyloxymethylacrylate, sec-octyl, α-allyloxymethylacrylate, tert-octyl, α-allyloxymethylacrylate, 2-ethylhexyl, α-allyloxymethylacrylate, capryl, α-allyloxymethylacrylate, nonyl, α-allyloxymethylacrylate, decyl, α-allyloxymethylacrylate, undecyl, α-allyloxymethylacrylate, lauryl, α-allyloxymethylacrylate, Allyloxymethylacrylate, tridecyl α-allyloxymethylacrylate, myristyl α-allyloxymethylacrylate, pentadecyl α-allyloxymethylacrylate, cetyl α-allyloxymethylacrylate, heptadecyl α-allyloxymethylacrylate, stearyl α-allyloxymethylacrylate, nonadecyl α-allyloxymethylacrylate, eicosyl α-allyloxymethylacrylate, ceryl α-allyloxymethylacrylate, melissyl α-allyloxymethylacrylate, crotyl α-allyloxymethylacrylate, 1,1-dimethyl-2-propenyl α-allyloxymethylacrylate, 2-methyl α-allyloxymethylacrylate α-allyloxymethylacrylic acid 3-methyl-2-butenyl, α-allyloxymethylacrylic acid 3-methyl-3-butenyl, α-allyloxymethylacrylic acid 2-methyl-3-butenyl, α-allyloxymethylacrylic acid oleyl, α-allyloxymethylacrylic acid linoleyl, α-allyloxymethylacrylic acid linolene, α-allyloxymethylacrylic acid cyclopentyl, α-allyloxymethylacrylic acid cyclopentylmethyl, α-allyloxymethylacrylic acid cyclohexyl, α-allyloxymethylacrylic acid cyclohexylmethyl, α-allyloxymethylacrylic acid 4-methylcyclohexyl , 4-tert-butylcyclohexyl α-allyloxymethylacrylate, tricyclodecanyl α-allyloxymethylacrylate, isobornyl α-allyloxymethylacrylate, adamantyl α-allyloxymethylacrylate, dicyclopentanyl α-allyloxymethylacrylate, dicyclopentenyl α-allyloxymethylacrylate, phenyl α-allyloxymethylacrylate, methylphenyl α-allyloxymethylacrylate, dimethylphenyl α-allyloxymethylacrylate, trimethylphenyl α-allyloxymethylacrylate, 4-tert-butylphenyl α-allyloxymethylacrylate, Benzyl α-allyloxymethylacrylate, diphenylmethyl α-allyloxymethylacrylate, diphenylethyl α-allyloxymethylacrylate, triphenylmethyl α-allyloxymethylacrylate, cinnamyl α-allyloxymethylacrylate, naphthyl α-allyloxymethylacrylate, anthranyl α-allyloxymethylacrylate, methoxyethyl α-allyloxymethylacrylate, methoxyethoxyethyl α-allyloxymethylacrylate, methoxyethoxyethoxyethyl α-allyloxymethylacrylate, 3-methoxybutyl α-allyloxymethylacrylate, α-allyloxymethylacrylate ethoxyethyl α-allyloxymethylacrylate, ethoxyethoxyethyl α-allyloxymethylacrylate, cyclopentoxyethyl α-allyloxymethylacrylate, cyclohexyloxyethyl α-allyloxymethylacrylate, cyclopentoxyethoxyethyl α-allyloxymethylacrylate, cyclohexyloxyethoxyethyl α-allyloxymethylacrylate, dicyclopentenyloxyethyl α-allyloxymethylacrylate, phenoxyethyl α-allyloxymethylacrylate, phenoxyethoxyethyl α-allyloxymethylacrylate, glycidyl α-allyloxymethylacrylate, β-allyloxymethylacrylate -methyl glycidyl, β-ethyl glycidyl α-allyloxymethyl acrylate, 3,4-epoxycyclohexylmethyl α-allyloxymethyl acrylate, 2-oxetanemethyl α-allyloxymethyl acrylate, 3-methyl-3-oxetanemethyl α-allyloxymethyl acrylate, 3-ethyl-3-oxetanemethyl α-allyloxymethyl acrylate, tetrahydrofuranyl α-allyloxymethyl acrylate, tetrahydrofurfuryl α-allyloxymethyl acrylate, tetrahydropyranyl α-allyloxymethyl acrylate, dioxazolanyl, dioxanyl α-allyloxymethyl acrylate, etc.

Specific examples of the cyclopolymerizable monomer (B) represented by the above general formula (1) other than the AMA-based monomers include, but are not limited to, 2-(N-allyl N-methylaminomethyl) methyl acrylate, 2-(N-allyl N-ethylaminomethyl) methyl acrylate, 2-(N-allyl N-t-butylaminomethyl) methyl acrylate, 2-(N-allyl N-cyclohexylaminomethyl) methyl acrylate, 2-(N-allyl N-phenylaminomethyl) methyl acrylate, and other 2-(N-allyl aminomethyl) acrylic acid-based monomers.

Specific examples of the cyclopolymerizable monomer (B) represented by the above general formula (2) include, but are not limited to, vinyloxymethylacrylic acid-based monomers such as methyl α-vinyloxymethylacrylate, ethyl α-vinyloxymethylacrylate, butyl α-vinyloxymethylacrylate, t-butyl α-vinyloxymethylacrylate, cyclohexyl α-vinyloxymethylacrylate, dicyclopentadienyl α-vinyloxymethylacrylate, isobornyl α-vinyloxymethylacrylate, adamantyl α-vinyloxymethylacrylate, and benzyl α-vinyloxymethylacrylate. In addition, examples of N-methyl-N-vinyl-2-(methoxycarbonyl)allylamine monomers include N-methyl-N-vinyl-2-(methoxycarbonyl)allylamine, N-ethyl-N-vinyl-2-(methoxycarbonyl)allylamine, N-t-butyl-N-vinyl-2-(methoxycarbonyl)allylamine, N-cyclohexyl-N-vinyl-2-(methoxycarbonyl)allylamine, and N-phenyl-N-vinyl-2-(methoxycarbonyl)allylamine. In addition, examples of 2-(N-vinyl aminomethyl)acrylic acid monomers include 2-(N-vinyl N-methylaminomethyl)methyl acrylate, 2-(N-vinyl N-ethylaminomethyl)methyl acrylate, 2-(N-vinyl N-t-butylaminomethyl)methyl acrylate, 2-(N-vinyl N-cyclohexylaminomethyl)methyl acrylate, and 2-(N-vinyl N-phenylaminomethyl)methyl acrylate.

The cyclopolymerizable monomer (B) may be a synthetic product or a commercially available product. There is no particular limitation on commercially available products, but examples thereof include AOMA (registered trademark) manufactured by Nippon Shokubai Co., Ltd.

The cyclopolymerizable monomer (B) can be used alone or in combination of two or more.

The content (mixture amount) of the cyclopolymerizable monomer (B) is 1 part by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the epoxy compound (A). If the content of the cyclopolymerizable monomer (B) is less than 1 part by mass, the action of the cyclopolymerizable monomer (B) cannot be obtained sufficiently. As a result, the durability of the optical member and the high-speed productivity of the optical member in the application of the adhesive composition become insufficient. From the same viewpoint, the content of the cyclopolymerizable monomer (B) is preferably 5 parts by mass or more with respect to 100 parts by mass of the epoxy compound (A). In addition, in the application of the adhesive composition, from the viewpoint of the balance of the polarizing plate performance, the content of the cyclopolymerizable monomer (B) is more preferably 20 parts by mass or more with respect to 100 parts by mass of the epoxy compound (A). In addition, in the application of the composition for forming a protective layer, from the viewpoint of further improving the durability of the optical member and the high-speed productivity of the optical member, the content of the cyclopolymerizable monomer (B) is more preferably 10 parts by mass or more with respect to 100 parts by mass of the epoxy compound (A). The content of the cyclopolymerizable monomer (B) is more preferably 20 parts by mass or more relative to 100 parts by mass of the epoxy compound (A). On the other hand, if the content of the cyclopolymerizable monomer (B) exceeds 100 parts by mass, the balance of the actions of the epoxy compound (A) and the cyclopolymerizable monomer (B) is lost. As a result, the adhesion to the adherend and the durability of the optical member become insufficient. From the same viewpoint, the content of the cyclopolymerizable monomer (B) is preferably 50 parts by mass or less relative to 100 parts by mass of the epoxy compound (A). Moreover, the content of the cyclopolymerizable monomer (B) is more preferably 40 parts by mass or less relative to 100 parts by mass of the epoxy compound (A), and even more preferably 30 parts by mass or less.

(Radically Polymerizable Monomer (C))
It is preferable that the curable resin composition for optical members according to one embodiment of the present invention further contains a radically polymerizable monomer (C) (also referred to simply as "radical polymerizable monomer (C)" in this specification) that does not form a ring structure in the molecule upon radical polymerization.

The radical polymerizable monomer (C) acts to further reduce the viscosity of the curable resin composition for optical components. The radical polymerizable monomer (C) also acts to more easily eliminate air bubbles that are generated, for example, when laminating a protective film in the production of a polarizing plate. In this way, the radical polymerizable monomer (C) can further increase the high-speed productivity of optical components, particularly in applications of the adhesive composition.

In addition, as described below, depending on its structure, the radical polymerizable monomer (C) can further increase the durability of the optical component.

The radical polymerizable functional group of the radical polymerizable monomer (C) is not particularly limited, and examples thereof include known radical polymerizable functional groups. For example, examples include groups having an unsaturated double bond such as a vinyl group and a (meth)acryloyl group. From the viewpoint of high-speed productivity of optical members in the application of the adhesive composition, the radical polymerizable monomer (C) is preferably a compound having a (meth)acryloyl group. Also, a compound having a (meth)acryloyloxy group or a (meth)acrylamide group is more preferable. And a compound having a (meth)acryloyloxy group is even more preferable. Also, it is sufficient that the radical polymerizable monomer (C) has only one radical polymerizable functional group in one molecule, and it is preferable that the radical polymerizable monomer (C) has only one radical polymerizable functional group in one molecule.

The radical polymerizable monomer (C) preferably contains a compound having a cationic polymerizable functional group, and more preferably is a compound having a cationic polymerizable functional group. The radical polymerizable monomer (C) having a cationic polymerizable functional group forms a crosslinked structure with the above-mentioned epoxy compound (A) or the above-mentioned cyclic polymerizable monomer (B). At this time, the glass transition temperature and elastic modulus after curing are significantly higher. In addition, the volume change due to heat is smaller, and the generation of internal stress, in other words, the decrease in strength, is more suppressed. As a result, the polarizing plate is less likely to shrink due to hot water. In addition, the occurrence of cracks in the polarizing plate during a temperature change from a low temperature to a high temperature is more suppressed, and the durability of the optical member is further improved. The radical polymerizable monomer (C) having a cationic polymerizable functional group only needs to have at least one cationic polymerizable functional group in one molecule, and it is preferable that the radical polymerizable monomer (C) has only one radical polymerizable functional group in one molecule.

The cationic polymerizable functional group possessed by the radical polymerizable monomer (C) is not particularly limited, and examples thereof include known cationic polymerizable functional groups. For example, specific examples of the cationic polymerizable functional group include an alicyclic ether group, a cyclic acetal group, a cyclic lactone group, a cyclic thioether group, a spiro orthoester group, and a vinyloxy group. Among these, from the viewpoint of high-speed productivity of optical members in applications of the adhesive composition and improvement of the durability of the optical members, an alicyclic ether group is preferred, an epoxy group and an oxetanyl group are more preferred, and an epoxy group is even more preferred. The epoxy group may be an alicyclic epoxy group.

Therefore, in a preferred embodiment of the present invention, the radical polymerizable monomer (C) is a compound having a (meth)acryloyl group and an epoxy group. In a more preferred embodiment of the present invention, the radical polymerizable monomer (C) is a compound having a (meth)acryloyloxy group or a (meth)acrylamide group, and an epoxy group. And, in a further preferred embodiment of the present invention, the radical polymerizable monomer (C) is a compound having a (meth)acryloyloxy group and an epoxy group (also referred to in this specification as an "epoxy group-containing (meth)acryloyloxy group-containing compound").

In a compound having a (meth)acryloyloxy group or a (meth)acrylamide group, and an epoxy group, the structure between the (meth)acryloyloxy group or the (meth)acrylamide group and the epoxy group (or the alicyclic epoxy group when present as an alicyclic epoxy group) is not particularly limited. Examples of the structure between them include a substituted or unsubstituted linear alkylene group having 1 to 8 carbon atoms, a substituted or unsubstituted branched alkylene group having 3 to 8 carbon atoms, or a substituted or unsubstituted cyclic alkylene group having 3 to 8 carbon atoms, a substituted or unsubstituted linear alkoxylene group having 1 to 8 carbon atoms, a substituted or unsubstituted branched alkoxylene group having 3 to 8 carbon atoms, or a substituted or unsubstituted cyclic alkoxylene group having 3 to 8 carbon atoms, or a substituted or unsubstituted arylene group having 6 to 12 carbon atoms, etc. Among these, unsubstituted linear alkylene groups having 1 to 8 carbon atoms are preferred, unsubstituted linear alkylene groups having 1 to 4 carbon atoms are more preferred, and methylene groups are even more preferred.

The epoxy equivalent of the epoxy group-containing (meth)acryloyloxy group-containing compound is not particularly limited, but is preferably 70 or more and 500 or less. The epoxy equivalent is more preferably 90 or more and 400 or less, and even more preferably 120 or more and 300 or less.

Specific examples of epoxy group-containing (meth)acryloyloxy group-containing compounds include, but are not limited to, glycidyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate glycidyl ether, 3,4-epoxybutyl (meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, etc. Among these, from the viewpoint of high-speed productivity of optical members in applications of the adhesive composition and improvement of the durability of optical members, glycidyl (meth)acrylate (also known as glycidyl (meth)acrylate) and 3,4-epoxycyclohexylmethyl (meth)acrylate are preferred. Furthermore, glycidyl methacrylate (also known as glycidyl methacrylate) and 3,4-epoxycyclohexylmethyl methacrylate are more preferred.

Specific examples of radical polymerizable monomers (C) other than epoxy group-containing (meth)acryloyloxy group-containing compounds are not particularly limited. Compounds having one (meth)acryloyl group in one molecule include (meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, phenoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, methylphenoxyethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethyl (meth)acrylate, ... (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, glycerol mono(meth)acrylate, benzyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate acrylate, phenoxydiethylene glycol (meth)acrylate, isobornyl (meth)acrylate, N-vinylpyrrolidone, (meth)acryloylmorpholine, urethane (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, (meth)acrylonitrile, (meth)acrylonitrile, (meth)acrylamide, N-methyl (meth)acrylamide, N-ethyl (meth)acrylamide, N-propyl (meth)acrylamide, N-isopropyl (meth)acrylamide, N-butyl (meth)acrylamide Examples of suitable methacrylates include dimethyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N,N-dimethylaminopropyl(meth)acrylamide, N-(hydroxyethyl)(meth)acrylamide, N-isopropyl(meth)acrylamide, N-methylol(meth)acrylamide, diacetone(meth)acrylamide, N,N-methylenebis(meth)acrylamide, ethylene glycol di(meth)acrylate, and 2-hydroxy-3-(meth)acryloyloxypropyl methacrylate. Examples of compounds having two or more (meth)acryloyl groups in one molecule include diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, butylene glycol di(meth)acrylate, nonaethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,3-butanediol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol tri(meth)acrylate, and trimethylolmethane tri(meth)acrylate. Among these, from the viewpoint of high-speed productivity of optical components in the application of the adhesive composition, phenoxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are preferred, and phenoxyethyl acrylate and 4-hydroxybutyl acrylate are more preferred.

The radical polymerizable monomer (C) may be a synthetic product or a commercially available product. Examples of commercially available epoxy group-containing (meth)acryloyloxy group-containing compounds include, but are not limited to, Acryester (registered trademark) G manufactured by Mitsubishi Chemical Corporation and Cyclomer (registered trademark) M100 manufactured by Daicel Corporation. Examples of commercially available products other than epoxy group-containing (meth)acryloyloxy group-containing compounds include, but are not limited to, Viscoat #192 manufactured by Osaka Organic Chemical Industry Co., Ltd. and 4HBA manufactured by Mitsubishi Chemical Corporation.

The radical polymerizable monomer (C) can be used alone or in combination of two or more.

When the radical polymerizable monomer (C) contains a compound further having at least one cationic polymerizable functional group in one molecule, the content (mixture amount) of the compound further having at least one cationic polymerizable functional group in one molecule is not particularly limited. The content of the compound further having at least one cationic polymerizable functional group in one molecule is preferably 50 parts by mass or more, more preferably 80 parts by mass or more, per 100 parts by mass of the radical polymerizable monomer (C). The content of the compound further having at least one cationic polymerizable functional group in one molecule is more preferably 100 parts by mass, per 100 parts by mass of the radical polymerizable monomer (C). Within these ranges, the polarizing plate shrinks less easily in hot water. Furthermore, the durability of the optical member is improved.

The content (mixture amount) of the radical polymerizable monomer (C) is not particularly limited, but is preferably 1 part by mass or more per 100 parts by mass of the epoxy compound (A). The content of the radical polymerizable monomer (C) is more preferably 5 parts by mass or more per 100 parts by mass of the epoxy compound (A), and even more preferably 10 parts by mass or more. In the use of the adhesive composition, from the viewpoint of the balance of the polarizing plate performance, the content of the radical polymerizable monomer (C) is particularly preferably 20 parts by mass or more per 100 parts by mass of the epoxy compound (A). In these ranges, the high-speed productivity of the optical member in the use of the adhesive composition and the durability of the optical member are further improved. On the other hand, the content of the radical polymerizable monomer (C) is preferably 100 parts by mass or less per 100 parts by mass of the epoxy compound (A). The content of the radical polymerizable monomer (C) is more preferably 50 parts by mass or less per 100 parts by mass of the epoxy compound (A), and even more preferably 30 parts by mass or less. In the use of the protective layer-forming composition, from the viewpoint of the balance of polarizing plate performance, it is particularly preferable that the content of the radical polymerizable monomer (C) is 20 parts by mass or less per 100 parts by mass of the epoxy compound (A). Within these ranges, the adhesion to the adherend and the durability of the optical member are further improved. That is, in a preferred embodiment of the present invention, the content of the radical polymerizable monomer (C) is 1 part by mass or more and 100 parts by mass or less per 100 parts by mass of the epoxy compound (A).

[Photopolymerization initiator, photosensitizer]
The curable resin composition for an optical member according to one embodiment of the present invention preferably further contains a photopolymerization initiator.

The photopolymerization initiator is not particularly limited, and any known photopolymerization initiator can be used. Among these, a photoradical polymerization initiator or a photocationic polymerization initiator is preferable. Furthermore, it is more preferable that the photopolymerization initiator includes a photoradical polymerization initiator and a photocationic polymerization initiator.

(Photocationic Polymerization Initiator)
The photo-cationic polymerization initiator is preferably a photo-acid generator, which is a compound that generates a strong acid when irradiated with light, and the strong acid attacks a compound containing an epoxy group, thereby initiating polymerization of the compound containing an epoxy group.

The photoacid generator is not particularly limited, and a known photoacid generator can be used. Specific examples include aromatic diazonium salts, onium salts such as aromatic iodonium salts and aromatic sulfonium salts, and iron-allene complexes. Among these, onium salts are preferred, and aromatic sulfonium salts are more preferred. Furthermore, triarylsulfonium salts are even more preferred, and triarylsulfonium hexafluorophosphate ( _{triarylsulfonium.PF6} salt) is particularly preferred.

Specific examples of aromatic diazonium salts, aromatic iodonium salts, and iron-allene complexes are not particularly limited, but include, for example, the compounds described in paragraphs "0044," "0045," and "0047" of JP2015-98513A.

Specific examples of aromatic sulfonium salts include, for example, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrakis(pentafluorophenyl)borate, diphenyl[4-(phenylthio)phenyl]sulfonium hexafluoroantimonate, 4,4'-bis[diphenylsulfonio]diphenylsulfide bishexafluorophosphate, 4,4'-bis[di(β-hydroxyethoxy)phenylsulfonio]diphenylsulfide bishexafluoroantimonate, 4,4'-bis[di(β-hydroxyethoxy)phenylsulfonio]diphenylsulfide bishexafluorophosphate, 7-[di(p-toluyl)sulfonio]-2-isopropylthioxanthone hexafluoroantimonate, 7-[di(p-toluyl)sulfonio]-2-isopropylthioxanthone Examples include tetrakis(pentafluorophenyl)borate, 4-phenylcarbonyl-4'-diphenylsulfonio-diphenylsulfide hexafluorophosphate, 4-(p-tert-butylphenylcarbonyl)-4'-diphenylsulfonio-diphenylsulfide hexafluoroantimonate, 4-(p-tert-butylphenylcarbonyl)-4'-di(p-toluyl)sulfonio-diphenylsulfide tetrakis(pentafluorophenyl)borate, and diphenyl[4-(phenylthio)phenyl]sulfonium phosphate.

The photoacid generator may be a commercially available product or a synthetic product. Commercially available products include, but are not limited to, CPI-100P, 101A, 200K, and 210S manufactured by San-Apro Co., Ltd., KAYARAD (registered trademark) PCI-220 and PCI-620 manufactured by Nippon Kayaku Co., Ltd., UVI-6990 manufactured by Union Carbide Corporation, ADEKA Optomer (registered trademark) SP-150 and SP-170 manufactured by ADEKA Corporation, and CI-5102 manufactured by Nippon Soda Co., Ltd. Examples include CIT-1370, 1682, CIP-1866S, 2048S, 2064S, DPI-101, 102, 103, 105, MPI-103, 105, BBI-101, 102, 103, 105, TPS-101, 102, 103, 105, MDS-103, 105, DTS-102, 103 manufactured by Midori Chemical Co., Ltd., and PI-2074 manufactured by Solvay Japan Co., Ltd.

The cationic photopolymerization initiator can be used alone or in combination of two or more.

The content (mixture amount) of the photocationic polymerization initiator is not particularly limited, but is preferably 0.01 parts by mass or more relative to 100 parts by mass of the total mass of the epoxy compound (A), the cyclopolymerizable monomer (B), and the optionally included radical polymerizable monomer (C). The content of the photocationic polymerization initiator is more preferably 0.1 parts by mass or more relative to 100 parts by mass of this total mass, and even more preferably 1 part by mass or more. Within these ranges, the curing reactivity of the photocurable resin composition for optical components becomes better. The content of the photocationic polymerization initiator is preferably 50 parts by mass or less relative to 100 parts by mass of this total mass. The content of the photocationic polymerization initiator is more preferably 30 parts by mass or less relative to 100 parts by mass of this total mass, and even more preferably 10 parts by mass or less. Within these ranges, the resin curability becomes better, and the adhesion to the adherend and the durability of the optical components are further improved.

(Photoradical polymerization initiator)
The photoradical polymerization initiator is not particularly limited, and a known photoradical polymerization initiator can be used. Specific examples include inorganic peroxides such as hydrogen peroxide, potassium persulfate, and ammonium persulfate. Other examples include organic peroxides such as t-butyl hydroperoxide, t-dibutyl peroxide, cumene hydroperoxide, acetyl peroxide, benzoyl peroxide, and lauroyl peroxide. Other examples include azo compounds such as azobisisobutyronitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbonitrile, methyl azobisisobutyrate, azobisisobutylamidine hydrochloride, and azobiscyanovaleric acid. Further examples thereof include acetophenones, benzoins, benzophenones, phosphine oxides, ketals, anthraquinones, thioxanthones, 2,3-dialkyldione compounds, disulfide compounds, fluoroamine compounds, aromatic sulfoniums, lophine dimers, onium salts, borate salts, active esters, active halogens, inorganic complexes, coumarins, etc. More specific examples thereof include acetophenones such as acetophenone, 3-methylacetophenone, benzyl dimethyl ketal, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropan-1-one, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropan-1-one. Further examples include benzophenones such as benzophenone, 4-chlorobenzophenone, and 4,4'-diaminobenzophenone. Further examples include benzoin ethers such as benzoin propyl ether and benzoin ethyl ether. Further examples include thioxanthones such as 4-isopropylthioxanthone. Further examples include xanthone, fluorenone, camphorquinone, benzaldehyde, anthraquinone, and the like. Among these, acetophenones are preferred, and 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropan-1-one is more preferred.

The photoradical polymerization initiator may be a commercially available product or a synthetic product. Examples of commercially available products include, but are not limited to, Omnirad (registered trademark) 127, 184, 819, 907, 651, 369, and TPO manufactured by IGM Resins B.V., Darocur (registered trademark) 1173 manufactured by Merck Ltd., Ezacure KIP150 and TZT manufactured by DKSH Japan Co., Ltd., and KAYACURE (registered trademark) BMS and DMBI manufactured by Nippon Kayaku Co., Ltd.

The photoradical polymerization initiator can be used alone or in combination of two or more.

The content (mixture amount) of the photoradical polymerization initiator is not particularly limited, but is preferably 0.01 parts by mass or more relative to 100 parts by mass of the total mass of the epoxy compound (A), the cyclopolymerizable monomer (B), and the optionally included radical polymerizable monomer (C). The content of the photoradical polymerization initiator is more preferably 0.1 parts by mass or more relative to 100 parts by mass of this total mass, and even more preferably 1 part by mass or more. Within these ranges, the curing reactivity of the adhesive composition is better. The content of the photoradical polymerization initiator is preferably 50 parts by mass or less relative to 100 parts by mass of this total mass. The content of the photoradical polymerization initiator is more preferably 30 parts by mass or less relative to 100 parts by mass of this total mass, and even more preferably 10 parts by mass or less. Within these ranges, the resin curability is better, and the adhesion to the adherend and the durability of the optical member are improved.

(Photosensitizer)
The curable resin composition for optical members according to one embodiment of the present invention preferably further contains a photosensitizer.

It is preferable to use the photosensitizer in combination with a photoradical polymerization initiator or a photocationic polymerization initiator. It is more preferable to use the photosensitizer in combination with a photopolymerization initiator, a photoradical polymerization initiator, and a photocationic polymerization initiator.

The photosensitizer is not particularly limited, and known photosensitizers can be used. Specific examples of photosensitizers include, but are not particularly limited to, anthracene compounds, pyrene compounds, carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, photoreducible dyes, and the like. More specifically, for example, anthracene compounds such as the compounds described in paragraphs "0058" to "0060" of JP-A-2015-98513 are included. Also, pyrene is included. Also, benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether, and α,α-dimethoxy-α-phenylacetophenone are included. Also, benzophenone derivatives such as benzophenone, 2,4-dichlorobenzophenone, o-benzoyl methyl benzoate, 4,4'-bis(dimethylamino)benzophenone, and 4,4'-bis(diethylamino)benzophenone are included. Other examples include thioxanthone derivatives such as 2-chlorothioxanthone, 2-isopropylthioxanthone, and 2,4-diethylthioxanthone. Other examples include anthraquinone derivatives such as 2-chloroanthraquinone and 2-methylanthraquinone. Other examples include acridone derivatives such as N-methylacridone and N-butylacridone. Other examples include α,α-diethoxyacetophenone, benzil, fluorenone, xanthone, uranyl compounds, halogen compounds, and the like. Among these, thioxanthone derivatives are preferred, and 2,4-diethylthioxanthone is more preferred.

The photosensitizer may be a commercially available product or a synthetic product. There is no particular limitation on commercially available products, but examples include KAYACURE (registered trademark) DMBI, BDMK, BP-100, BMBI, DETX-S, and EPA manufactured by Nippon Kayaku Co., Ltd., Anthracure (registered trademark) UVS-1331 and UVS-1221 manufactured by Kawasaki Kasei Chemical Industries, Ltd., and Ubecryl P102, 103, 104, and 105 manufactured by UCB.

In one embodiment of the present invention, the curable resin composition for optical components may or may not contain a photosensitizer when used as an adhesive composition, but it may be preferable to contain a photosensitizer. In one embodiment of the present invention, the curable resin composition for optical components may or may not contain a photosensitizer when used as a composition for forming a protective layer, but it may be preferable not to contain a photosensitizer.

When a photosensitizer is contained, the content (mixture amount) of the photosensitizer is not particularly limited. The content of the photosensitizer is preferably 0.001 parts by mass or more with respect to 100 parts by mass of the total mass of the epoxy compound (A), the cyclopolymerizable monomer (B), and the optionally contained radical polymerizable monomer (C). The content of the photosensitizer is more preferably 0.01 parts by mass or more with respect to this total mass of 100 parts by mass, and even more preferably 0.1 parts by mass or more. Within these ranges, the curing reactivity of the adhesive composition is better. The content of the photosensitizer is preferably 10 parts by mass or less with respect to this total mass of 100 parts by mass. The content of the photosensitizer is more preferably 1 part by mass or less with respect to this total mass of 100 parts by mass, and even more preferably 0.5 parts by mass or less. Within these ranges, the resin curability is better, and the adhesion to the adherend and the durability of the optical member are further improved.

[Other ingredients]
The curable resin composition for optical members according to one embodiment of the present invention may contain other components in addition to the components described above, as necessary, within a range that does not significantly impair the effects of the present invention.

The other components are not particularly limited, and known components in the field of curable resin compositions can be used. For example, other polymerizable components other than those mentioned above, ultraviolet absorbers, antioxidants, heat stabilizers, silane coupling agents, inorganic fillers, softeners, antioxidants, antiaging agents, stabilizers, tackifier resins, modified resins (polyol resins, phenolic resins, acrylic resins, polyester resins, polyolefin resins, etc.), leveling agents, defoamers, plasticizers, dyes, pigments (coloring pigments, extender pigments, etc.), treatment agents, ultraviolet blocking agents, fluorescent brighteners, dispersants, light stabilizers, antistatic agents, lubricants, oxidizing agents, reducing agents, etc. can be mentioned.

[Curing Means]
The curing means of the curable resin composition for optical members according to one embodiment of the present invention is not particularly limited, but is preferably light irradiation, and more preferably ultraviolet irradiation. That is, the curable resin composition for optical members according to one embodiment of the present invention is preferably a photocurable resin composition, and more preferably an ultraviolet curable resin composition.

[Method for producing curable resin composition for optical members]
The manufacturing method of the curable resin composition for optical members according to one embodiment of the present invention is not particularly limited, and the above components are usually mixed to obtain the curable resin composition for optical members. An organic solvent may be used appropriately to adjust the viscosity. There is also no particular limit to the mixing method, and for example, a method of thoroughly stirring and mixing the liquid at room temperature (20°C or higher and 25°C or lower) in a room that is shielded from ultraviolet rays (UV light) until the liquid becomes uniform can be mentioned.

[Application]
The use of the curable resin composition for optical members is not particularly limited, and it can be appropriately used for known optical members. Among these, for example, it is preferable to use the curable resin composition for optical members as an adhesive composition to bond adherends used for optical applications. At this time, the cured product of the curable resin composition for optical members becomes an adhesive layer. Also, for example, it is preferable to use the curable resin composition for optical members as a composition for forming a protective layer to protect members used for optical applications. At this time, the cured product of the curable resin composition for optical members becomes a protective layer. In a particularly preferred embodiment of the present invention, the curable resin composition for optical members is a curable resin composition for polarizing plates used for polarizing plates.

<Cured Product>
Another aspect of the present invention relates to a cured product of the above-mentioned curable resin composition for optical members. The composition, characteristics, production method, uses, etc. of the curable resin composition for optical members are the same as those described for the above-mentioned curable resin composition for optical members.

The cured product according to one embodiment of the present invention more preferably constitutes an adhesive layer. The preferred thickness of the adhesive layer is the same as that of the polarizing plate described below. The cured product according to one embodiment of the present invention more preferably constitutes a protective layer. The preferred thickness of the protective layer is the same as that of the polarizing plate described below.

A method for obtaining a cured product according to one embodiment of the present invention, that is, a method for curing the above-mentioned curable resin composition for optical members, includes a method of performing light irradiation. The irradiation light is not particularly limited as long as it can cause the curing reaction to proceed, but preferably includes ultraviolet light. As a light source for ultraviolet light, it is preferable to use a light source having an emission distribution at a wavelength of 400 nm or less. Examples of light sources are the same as those described in the description of the polarizing plate below. The amount of ultraviolet light irradiation is not particularly limited, but it is preferable that the amount of ultraviolet light irradiation in the wavelength region effective for activating the photopolymerization initiator is in the range of 100 mJ/m ² or more and 2000 mJ/m ² or less. After ultraviolet light irradiation, a dark reaction proceeds for the epoxy compound (A), so it is preferable to store it at room temperature (20°C or more and 25°C or less) for about 16 hours to 30 hours immediately after ultraviolet light irradiation.

<Polarizing Plate>
Another aspect of the present invention relates to a polarizing plate including an adhesive layer or a protective layer containing the cured product of the above-mentioned curable resin composition for optical members.

A preferred embodiment of the present invention is not particularly limited, but includes, for example, a polarizing plate including a polarizer such as a polarizing film in which iodine or a dichroic dye is adsorbed and oriented in a polyvinyl alcohol resin, and a protective layer or an adhesive layer disposed on at least one surface of the polarizer. Here, the protective layer or the adhesive layer includes a cured product of the above-mentioned curable resin composition for optical members.

A particularly preferred embodiment of the present invention relates to a polarizing plate having a polarizer and two protective films. In this embodiment, one side of the polarizer and one protective film are bonded with the above-mentioned curable resin composition for optical components, which is an adhesive composition. The other side of the polarizer and the other protective film are bonded with the above-mentioned curable resin composition for optical components, which is an adhesive composition. That is, this embodiment relates to a polarizing plate (polarizing plate with double-sided protective films) having a polarizer and two protective films, in which one side of the polarizer and one protective film are bonded with an adhesive layer containing a cured product of the above-mentioned curable resin composition for optical components, and the other side of the polarizer and the other protective film are bonded with an adhesive layer containing a cured product of the above-mentioned curable resin composition for optical components.

Another particularly preferred embodiment of the present invention relates to a polarizing plate having a polarizer and one protective film. In this embodiment, one side of the polarizer and one protective film are bonded with the above-mentioned curable resin composition for optical components, which is an adhesive composition. The other side of the polarizer is protected with a cured product of the above-mentioned curable resin composition for optical components, which is a composition for forming a protective layer. That is, this embodiment relates to a polarizing plate (polarizing plate with one-sided protective film) having a polarizer and one protective film, in which one side of the polarizer and one protective film are bonded with an adhesive layer containing a cured product of the above-mentioned curable resin composition for optical components, and a protective layer containing a cured product of the curable resin composition for optical components is arranged so as to be in direct contact with the other side of the polarizer.

[Polarizer]
The polarizer is not particularly limited, and a known polarizer can be used. For example, a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, or an ethylene-vinyl acetate copolymer partially saponified film is uniaxially stretched after adsorbing a dichroic material such as iodine or a dichroic dye, or a polyene-based oriented film such as a dehydrated product of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride, can be mentioned.

Among these, a polarizer manufactured by dyeing a polyvinyl alcohol film having an average degree of polymerization of 2000 to 2800 and a degree of saponification of 90 mol % to 100 mol % with iodine and stretching it uniaxially 5 to 6 times is particularly preferred. More specifically, such a polarizer is obtained by, for example, immersing a polyvinyl alcohol film in an aqueous solution of iodine, dyeing it, and stretching it. As the aqueous solution of iodine, for example, it is preferable to immerse it in an aqueous solution of iodine/potassium iodide (for example, a mass ratio of 2/3) at 0.1 mass % to 1.0 mass %. If necessary, it may be immersed in an aqueous solution of boric acid, boric acid ester, potassium iodide, etc. at 50 ° C. to 70 ° C., or in order to wash or prevent uneven dyeing, it may be immersed in water at 25 ° C. to 35 ° C. The stretching may be performed after dyeing with iodine, stretching while dyeing, or dyeing with iodine after stretching. After dyeing and stretching, the fabric may be washed with water and dried at a temperature of 35°C to 55°C for 1 minute to 10 minutes.

The thickness of the polarizer is not particularly limited, but from the viewpoint of polarization performance, it is preferably 1 μm or more, more preferably 5 μm or more, and even more preferably 7 μm or more. Also, from the viewpoint of thinning the optical component, it is preferably 30 μm or less, more preferably 25 μm or less, and even more preferably 20 μm or less.

[Protective film]
The protective film is not particularly limited, and any known film can be used. Among these, a film made of a material having excellent transparency, mechanical strength, thermal stability, moisture blocking property, isotropy, etc. is preferred, and a resin film is more preferred. The resin constituting the protective film is not particularly limited, but examples thereof include cellulose-based resins such as cellulose diacetate and cellulose triacetate, polyester-based resins such as polyethylene terephthalate and polyethylene naphthalate, acrylic resins such as polymethyl methacrylate, styrene-based resins such as polystyrene and acrylonitrile-styrene copolymers (AS resins), polycarbonate-based resins, polyolefins such as polyethylene, polypropylene, polyolefins having a cyclo- or norbornene structure, and ethylene-propylene copolymers, vinyl chloride-based resins, amide-based resins such as nylon and aromatic polyamide, imide-based resins, sulfone-based resins, polyethersulfone-based resins, polyetheretherketone-based resins, polyphenylene sulfide-based resins, vinyl alcohol-based resins, vinylidene chloride-based resins, vinyl butyral-based resins, arylate-based resins, polyoxymethylene-based resins, epoxy-based resins, and blends of these resins.

Among these, the polarizing plate protective film is preferably a cellulose-based resin (cellulose-based film), which is an ester of cellulose and a fatty acid, a cycloolefin polymer (COP film), a cycloolefin copolymer (COC film), a polyethylene terephthalate (PET film), or an acrylic resin (acrylic film). Examples of cellulose-based resins include cellulose triacetate (TAC film), cellulose diacetate (DAC film), cellulose tripropionate (CTP film), cellulose dipropionate (CDP film), and cellulose acetate propionate (CAP film). Among these, cellulose triacetate (TAC film), cycloolefin polymer (COP film), polyethylene terephthalate (PET film), or an acrylic resin (acrylic film) are preferred from the viewpoints of availability and cost. In addition, from the viewpoints of availability and moisture permeability, cycloolefin polymer (COP film), polyethylene terephthalate (PET film), or an acrylic resin (acrylic film) are preferred. If the protective film has high moisture permeability, moisture may easily pass through the protective film and enter the polarizer side, which may cause a deterioration in the quality of the polarizer. However, cycloolefin polymer (COP film), polyethylene terephthalate (PET film), or acrylic resin (acrylic film) can significantly suppress such deterioration in quality. In a polarizing plate with double-sided protective films, a combination of cycloolefin polymer (COP film) and polyethylene terephthalate (PET film) is particularly preferred as the protective film. Also, in a polarizing plate with one-sided protective film, polyethylene terephthalate (PET film) is particularly preferred as the protective film.

Although saponified cellulose triacetate can be used, unsaponified cellulose triacetate is more preferable. Examples of cycloolefin polymers include polymers whose constituent components are polymers obtained by hydrogenating ring-opening polymers of tetracyclododecenes, as described in JP-B-2-9619.

The protective film may further include a functional layer. The functional layer may be provided on only one side of the resin film or on both sides, but is preferably provided on only one side. The functional layer is not particularly limited, but may be a known layer such as a hard coat layer, an anti-reflection layer (AR layer), an anti-glare layer (AG layer), or an easy-adhesion layer.

Commercially available COP films include, but are not limited to, Arton (registered trademark) manufactured by JSR Corporation, Zeonex (registered trademark) series, Zeonor (registered trademark) series manufactured by Zeon Corporation. Commercially available PET films include, but are not limited to, Cosmoshine (registered trademark) series manufactured by Toyobo Co., Ltd. (e.g., SRF, etc.). Commercially available acrylic films include, but are not limited to, acrylic film RT, SO, HI series manufactured by Kuraray Co., Ltd. Commercially available TAC films include, but are not limited to, UV-50, UV-80, SH-80, TD-80U, TD-TAC, UZ-TAC manufactured by Fujifilm Corporation, and KC series manufactured by Konica Minolta, Inc.

The surface of the protective film is preferably modified by corona discharge treatment. There is no particular restriction on the method of corona discharge treatment. It can be treated using a general corona discharge treatment device (for example, manufactured by Kasuga Electric Co., Ltd.). By corona discharge treatment, active groups such as hydroxyl groups are formed on the surface of the protective film. It is considered that such active groups contribute to improving the adhesion to the polarizer via the above-mentioned curable resin composition for optical members. When saponified cellulose triacetate is used as the protective film, the effect of improving the adhesion can be expected to be similar to that of corona discharge treatment, so corona discharge treatment is not necessarily required. However, since saponification treatment is a complicated process and expensive, it is preferable in terms of the manufacturing process to use unsaponified cellulose triacetate after corona discharge treatment.

The discharge amount during corona treatment is not particularly limited, but is preferably 30 W·min/ ^m2 or more and 300 W·min/ ^m2 or less, and more preferably 50 W·min/ ^m2 or more and 250 W·min/ ^m2 or less. Within these ranges, the adhesiveness to the polarizer via the curable resin composition for optical members can be improved without deteriorating the protective film itself. Here, the discharge amount is the amount of work on the target object by corona discharge calculated by the following formula, and the corona discharge power is determined based on this.

[Method of manufacturing polarizing plate]
The method for producing the polarizing plate is not particularly limited, and a known method can be used. The structure of the polarizing plate produced is also not particularly limited. Hereinafter, an example of a preferred method for producing a polarizing plate will be described, but the polarizing plate of the present invention is not limited to the one produced by this method.

For example, a polarizing plate with protective films on both sides is preferably manufactured by the following method. A polarizer and two protective films are bonded together using the above-mentioned curable resin composition for optical components as an adhesive composition. Here, the polarizer and one of the protective films are laminated together with the above-mentioned curable resin composition for optical components interposed therebetween. The polarizer and the other protective film are laminated together with the above-mentioned curable resin composition for optical components interposed therebetween. In this way, a pre-light-irradiation laminate (pre-light-irradiation polarizing plate) is formed. Then, the obtained pre-light-irradiation laminate is irradiated with light. As a result, the above-mentioned curable resin composition for optical components exhibits adhesiveness and forms an adhesive layer. In this way, a polarizing plate with protective films on both sides is obtained.

For example, a polarizing plate with a protective film on one side is preferably manufactured by the following method. A polarizer and one protective film are bonded together using the above-mentioned curable resin composition for optical members as an adhesive composition. A polarizer and a film (transfer film) to which the above-mentioned curable resin composition for optical members is applied as a protective layer forming composition on one surface of a release film are bonded together using the above-mentioned curable resin composition for optical members. Here, the polarizer and the protective film are laminated so as to interpose the above-mentioned curable resin composition for optical members. Also, the polarizer and the transfer film are laminated so that the above-mentioned curable resin composition for optical members on the release film and the polarizer are in direct contact with each other. In this way, a laminate before light irradiation (polarizing plate before light irradiation) is formed. Then, light is irradiated to the obtained laminate before light irradiation. As a result, the above-mentioned curable resin composition for optical members exhibits adhesiveness to form an adhesive layer and a protective layer. Furthermore, the release film is peeled off from the laminate after light irradiation to expose the protective layer. In this way, a polarizing plate with a protective film on one side is obtained. As the release film, a known release film can be used, such as a PET film.

When applying the above-mentioned curable resin composition for optical components, it may be applied to either a protective film or a polarizer, or it may be applied to both. The application method is not particularly limited, but is preferably a coating method, and various methods such as a direct dropping method, a roll coating method, a spraying method, and a dipping method can be used.

When the above-mentioned curable resin composition for optical members is used as an adhesive composition, it is preferable to apply the curable resin composition for optical members so that the adhesive layer after drying has a thickness of 10 nm or more. It is more preferable to apply the composition so that the thickness is 500 nm or more. And it is even more preferable to apply the composition so that the thickness is 1 μm or more. That is, the adhesive layer is preferably 10 nm or more, more preferably 500 nm or more, and even more preferably 1 μm or more. In these ranges, the in-plane thickness becomes more uniform, and the adhesion to the adherend is further improved. It is also preferable to apply the curable resin composition for optical members so that the adhesive layer after drying has a thickness of 15 μm or less. It is also more preferable to apply the composition so that the thickness is 10 μm or less. And it is even more preferable to apply the composition so that the thickness is 3 μm or less. That is, the adhesive layer is preferably 15 μm or less, more preferably 10 μm or less, and even more preferably 3 μm or less. Within these ranges, air bubbles that occur when laminating the protective film during polarizing plate production are more easily eliminated, further improving high-speed productivity.

When the above-mentioned curable resin composition for optical members is used as a composition for forming a protective layer, the curable resin composition for optical members is preferably applied so that the thickness of the protective layer after drying is 100 nm or more. It is more preferable to apply the composition so that the thickness is 1 μm or more. And it is even more preferable to apply the composition so that the thickness is 3 μm or more. That is, the protective layer is preferably 100 nm or more, more preferably 1 μm or more, and even more preferably 3 μm or more. In these ranges, the in-plane thickness becomes more uniform, and the moisture transmittance of the protective layer is further reduced, and the durability of the polarizing plate is further improved. Also, the curable resin composition for optical members is preferably applied so that the thickness of the protective layer after drying is 15 μm or less. It is more preferable to apply the composition so that the thickness is 12 μm or less. And it is even more preferable to apply the composition so that the thickness is 10 μm or less. That is, the protective layer is preferably 15 μm or less, more preferably 12 μm or less, and even more preferably 10 μm or less. Within these ranges, the resin will have better curing properties, and the adhesion to the adherend and the durability of the optical component will be improved. In addition, the possibility of problems such as yellowing and deformation of the protective layer, which occur more frequently when the film thickness is excessive, will be reduced.

Thus, in a preferred embodiment of the present invention, the thickness of the adhesive layer or protective layer is 15 μm or less.

The thickness of the adhesive layer and the protective layer can be adjusted by the solids concentration in the solution of the photocurable resin composition for optical components and the coating device for the photocurable resin composition for optical components. The thickness of the adhesive layer and the protective layer can be confirmed by observing the cross section with a scanning electron microscope (SEM).

After applying the photocurable resin composition for optical components, the polarizer and a film (protective film or transfer film) are laminated together. The lamination method is not particularly limited, and any known method can be used. The lamination of the polarizer and the film is preferably performed by a roll-to-roll method. In the roll-to-roll method, it is preferable to feed the film from two film rolls and the polarizer from the polarizer roll, and laminate them together. The lamination of the polarizer and these films may be performed simultaneously or sequentially, but is preferably performed simultaneously. For example, a roll laminator or the like can be used for lamination.

After lamination, it is preferable to irradiate the laminate with light before light irradiation in order to cure the photocurable resin composition. The type of irradiation light is not particularly limited as long as it can cause the curing reaction to proceed, but ultraviolet light is preferred. As a light source for ultraviolet light, it is preferable to use a light source having an emission distribution at a wavelength of 400 nm or less. Examples of light sources include, but are not particularly limited to, low pressure mercury lamps, medium pressure mercury lamps, high pressure mercury lamps, ultra-high pressure mercury lamps, chemical lamps, black light lamps, microwave excited mercury lamps, metal halide lamps, etc., which have an emission distribution at a wavelength of 400 nm or less.

The amount of ultraviolet irradiation is not particularly limited, but it is preferable that the amount of ultraviolet irradiation in a wavelength region effective for activating a photopolymerization initiator is within the range of 100 mJ/m ² to 2000 mJ/m ^2. Within this range, the reaction time is appropriate, and deterioration of the photocurable resin composition itself and the polarizer due to heat radiated from the lamp and heat generated during polymerization is further suppressed.

After UV irradiation, a dark reaction may occur in the epoxy compound (A), so it is preferable to store the polarizing plate at room temperature (20°C or higher and 25°C or lower) for 16 to 30 hours immediately after UV irradiation. In this case, the polarizing plate is completed when the curing is complete.

<Image display device>
Yet another embodiment of the present invention relates to an image display device including the above polarizing plate.

The image display device is not particularly limited and can be applied to known image display devices, but is preferably an organic EL display device (organic EL display) or a liquid crystal display device (liquid crystal display). In addition, in the image display device according to one embodiment of the present invention, the polarizing plate is preferably applied to a panel such as a liquid crystal panel or an organic EL panel.

One example of a preferred image display device is a liquid crystal display device having a configuration in which a liquid crystal panel (polarizing plate/liquid crystal cell/polarizing plate) and a backlight unit are stacked in this order from the viewing side. In this liquid crystal display device, at least one of these polarizing plates is the above-mentioned polarizing plate. Here, when the above-mentioned polarizing plate is a polarizing plate with a protective film on one side, it is preferable to arrange it so that the protective layer faces the liquid crystal cell side.

The mode of the liquid crystal display device is not particularly limited, but if the polarizing plate is a polarizing plate with a protective film on one side, a horizontal electric field mode such as an IPS mode (In-Plane Switching mode) or an FFS mode (Fringe-Field Switching mode) is preferred.

The image display device according to one embodiment of the present invention is particularly capable of exhibiting excellent durability even under harsh temperature and humidity conditions.

The effects of the present invention will be explained using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples.

<Preparation of Curable Resin Composition for Polarizing Plate>
[Preparation of Curable Resin Compositions R1 to R13 for Forming Adhesive Layer for Polarizing Plate]
In an ultraviolet shielding environment, the components shown in Tables 1 and 2 were mixed and stirred in a temperature-controlled room at 23° C. and a relative humidity of 50% RH in the amounts shown in Tables 1 and 2 until the mixture was visually uniform, thereby obtaining curable resin compositions for polarizing plates R1 to 13. The unit of the amount of each component in Table 1 is "g."

[Preparation of Curable Resin Compositions R14 to R20 for Forming Protective Layer for Polarizing Plate]
In an ultraviolet shielding environment, the components shown in Table 3 were stirred and mixed in the amounts shown in Table 3 in a temperature-controlled room at 23°C and a relative humidity of 50% RH until the mixture was visually uniform, to obtain curable resin compositions for polarizing plates R14 to 20. The unit of the amount of each component in Table 1 is "g."

Details of each component in Tables 1 to 3 are shown below.

(Epoxy compound (A))
Cel2021P: Celoxide (registered trademark) 2021P (manufactured by Daicel Corporation, 3',4'-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate, a bifunctional alicyclic epoxy group-containing compound, epoxy equivalent weight 128 to 133)
EHPE3150: (manufactured by Daicel Corporation, 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol, polyfunctional alicyclic group-containing epoxy group-containing compound, epoxy equivalent 170 to 190)
EX-141: Denacol (registered trademark) EX-141 (manufactured by Nagase ChemteX Corporation, phenyl glycidyl ether, monofunctional aromatic group-containing epoxy group-containing compound, epoxy equivalent 151)
157S70: jER (registered trademark) 157S70 (manufactured by Mitsubishi Chemical Corporation, bisphenol A novolac type epoxy resin having the structure shown in the following formula, polyfunctional aromatic group-containing epoxy group-containing compound, epoxy equivalent weight 200 to 220)

(Cyclopolymerizable monomer (B))
AOMA: Cyclopolymerizable monomer AOMA (registered trademark) (manufactured by Nippon Shokubai Co., Ltd., methyl-2-allyloxymethyl acrylate)
(Radically Polymerizable Monomer (C))
#192: Viscoat #192 (Osaka Organic Chemical Industry Co., Ltd., phenoxyethyl acrylate, a radical polymerizable monomer that does not have a cationic polymerizable functional group in the molecule and does not form a ring structure in the molecule during radical polymerization)
・4HBA: (manufactured by Mitsubishi Chemical Corporation, 4-hydroxybutyl acrylate, a radical polymerizable monomer that does not have a cationic polymerizable functional group in the molecule and does not form a ring structure in the molecule during radical polymerization)
GMA: Acryester (registered trademark) G (manufactured by Mitsubishi Chemical Corporation, glycidyl methacrylate, a radical polymerizable monomer having a cationic polymerizable functional group in the molecule and not forming a ring structure in the molecule upon radical polymerization)
M-100: Cyclomer (registered trademark) M100 (manufactured by Daicel Corporation, 3,4-epoxycyclohexylmethyl methacrylate, a radical polymerizable monomer having a cationic polymerizable functional group in the molecule and not forming a ring structure in the molecule upon radical polymerization, epoxy equivalent 195 to 215).

(Photopolymerization initiator, photosensitizer)
CPI-100P: CPI (registered trademark)-100P (manufactured by San-Apro Ltd.,
Propylene carbonate solution of triarylsulfonium _PF6 salt, solids concentration 50% by mass, photocationic polymerization initiator (photoacid generator)
Omnirad 127: Omnirad (registered trademark) 127 (manufactured by IGM Resins B.V., 2-hydroxy-1-(4-(4-(2-hydroxy-2-methylpropionyl)benzyl)phenyl)-2-methylpropan-1-one, photoradical polymerization initiator)
DETX-S: KAYACURE (registered trademark) DETX-S (manufactured by Nippon Kayaku Co., Ltd., 2,4-diethylthioxanthone, photosensitizer)
In addition, in the following Tables 1 to 3, when the amount of a component in the curable resin composition for polarizing plates is left blank, it means that the component is not included.

<Production of Polarizing Plate>
[Manufacture of Polarizer 1]
Polarizer 1 was produced by the following method. First, a polyvinyl alcohol film having an average degree of polymerization of 2400 and a saponification degree of 99.9 mol% and a thickness of 45 μm was immersed in warm water at 28 ° C. for 90 seconds to swell. Next, the polyvinyl alcohol film was immersed in an aqueous solution of iodine/potassium iodide (mass ratio 2/3) with a concentration of 0.6 mass %, and was dyed while being stretched 2.1 times. Thereafter, the film was stretched in an aqueous solution of boric acid ester at 60 ° C. to a total stretch ratio of 5.8 times, washed with water, and dried at 45 ° C. for 3 minutes. In this way, polarizer 1 (thickness 18 μm) was produced.

[Production of polarizing plates P1 to P13 with double-sided protective films]
FIG. 1 is a schematic diagram showing a method of laminating a film and a polarizer in the production of polarizing plates P1 to P13.

As shown in FIG. 1, the polarizer 1 obtained above was sandwiched between film 3 (COP film; Zeonor (registered trademark) ZF-14, manufactured by Zeon Corporation, adhesive surface corona-treated, thickness 50 μm) and film 4 (PET film; Cosmoshine (registered trademark) SRF, manufactured by Toyobo Co., Ltd., thickness 80 μm). Next, the curable resin composition for polarizing plates R1 obtained above was dropped as adhesive composition 2 between film 3 and polarizer 1, and between film 4 and polarizer 1 in appropriate amounts using a dropper. Next, film 3, polarizer 1, and film 4 were bonded together using adhesive composition 2 (curable resin composition for polarizing plates R1) by a roll press equipped with rolls 6 and 7. In this way, a polarizing plate 5 before ultraviolet irradiation was obtained. Note that these operations were performed in an ultraviolet shielding environment.

The obtained polarizing plate 5 before UV irradiation was irradiated with UV rays at an exposure dose of 1000 mJ/ ^cm2 (365 nm, metal halide lamp) from the side of the film 3. Note that the processes from laminating the film 3 using the curable resin composition for polarizing plates R1, the polarizer 1 and the film 4 to UV irradiation were carried out at 23°C and a relative humidity of 50%.

The polarizing plate after UV irradiation was then stored in a temperature-controlled room (23°C, 50% RH) for 24 hours to harden the curable resin composition for polarizing plates R1, completing the polarizing plate P1.

Here, in the completed polarizing plate P1, films 3 and 4 each serve as a polarizing plate protective film. The thickness of the adhesive layer (i.e., the layer made of the cured product of the curable resin composition for polarizing plates) in the completed polarizing plate P1 was 2.0 μm.

The laminate structure of the completed polarizing plate P1 is, from the film 4 side, film 4 (PET film, polarizing plate protective film) / cured layer (adhesive layer) of curable resin composition R1 for polarizing plate / polarizer 1 / cured layer (adhesive layer) of curable resin composition R1 for polarizing plate / film 3 (COP film, polarizing plate protective film).

Polarizing plates P2 to P13 were manufactured in the same manner as polarizing plate P1, except that polarizing plate curable resin compositions R2 to R13 were used instead of polarizing plate curable resin composition R1. The thickness of the adhesive layer in these completed polarizing plates was 2.0 μm, the same as the adhesive layer in polarizing plate P1.

[Production of polarizing plates P14 to P20 with one-sided protective film]
FIG. 2 is a schematic diagram showing a method for laminating a film and a polarizer in the production of the polarizing plates P14 to P20.

As shown in FIG. 2, the polarizer 1 obtained above was sandwiched between a film 3 (PET film; Lumirror (registered trademark) T60, manufactured by Toray Industries, Inc., thickness 25 μm) on one surface of which an appropriate amount of the curable resin composition for polarizing plates R14 was applied as a composition for forming a protective layer 2', and a film 4 (PET film; Cosmoshine (registered trademark) SRF, manufactured by Toyobo Co., Ltd., thickness 80 μm). Next, an appropriate amount of the curable resin composition for polarizing plates R14 obtained above was dropped as an adhesive composition 2 between the film 4 and the polarizer 1 using a dropper. Next, the film 3, the polarizer 1, and the film 4 were bonded together using the composition for forming a protective layer 2' (curable resin composition for polarizing plates R14) and the adhesive composition 2 (curable resin composition for polarizing plates R14) by a roll press equipped with rolls 6 and 7. That is, the film 3 was bonded to the polarizer 1 using the protective layer forming composition 2', and the film 4 was bonded to the polarizer 1 using the adhesive composition 2, and the film 3, the polarizer 1, and the film 4 were bonded together. In this way, a polarizing plate 5 before UV irradiation was obtained. Note that these operations were performed in a UV-shielded environment.

The obtained polarizing plate 5 before UV irradiation was irradiated with UV rays at an exposure dose of 1000 mJ/ ^cm2 (365 nm, metal halide lamp) from the side of the film 3. Note that the processes from laminating the film 3 using the curable resin composition for polarizing plates R14, the polarizer 1 and the film 4 to UV irradiation were carried out at 23°C and a relative humidity of 50% RH.

Then, the polarizing plate after UV irradiation was stored in a constant temperature room (23°C, relative humidity 50% RH) for 24 hours to harden the curable resin composition for polarizing plate R14. Then, film 3 was peeled off from the polarizing plate after UV irradiation to complete polarizing plate P14.

Here, in the completed polarizing plate P14, the layer composed of the cured product of the curable resin composition for polarizing plates R14 coated on one surface of the film 3 becomes the protective layer. Also, in the completed polarizing plate P14, the film 4 becomes the polarizing plate protective film. And, the thickness of the protective layer (i.e., the cured layer of the curable resin composition for polarizing plates) in the completed polarizing plate P14 was 7.0 μm. And, the thickness of the adhesive layer (i.e., the cured layer of the curable resin composition for polarizing plates) in the completed polarizing plate P14 was 2.0 μm.

The laminate structure of the completed polarizing plate P14 is, from the film 4 side, film 4 (PET film, polarizing plate protective film) / cured layer of curable resin composition R14 for polarizing plate (adhesive layer) / polarizer 1 / cured layer of curable resin composition R14 for polarizing plate (protective layer).

Polarizing plates P15 to P20 were also manufactured in the same manner as polarizing plate P14, except that polarizing plate curable resin compositions R15 to R20 were used instead of polarizing plate curable resin composition R14. The thicknesses of the protective layer and adhesive layer in these completed polarizing plates were 7.0 μm and 2.0 μm, respectively, the same as the protective layer and adhesive layer in polarizing plate P14.

<Evaluation of Polarizing Plate>
[Physical property evaluation]
(Cutting test)
The polarizing plates P1 to P20 obtained above were cut into pieces of 50 mm x 50 mm using a Thomson blade, and the state of peeling at the edge during cutting was visually observed. For the edge peeling in the polarizing plates P1 to P13 with double-sided protective films, the state of peeling of the protective films on both sides was confirmed. For the edge peeling in the polarizing plates P14 to P20 with one-sided protective film, the state of peeling of the protective film and protective layer was confirmed. As an evaluation criterion, a case in which the maximum value of the vertical length from the cut edge side in the peeled part was 0.5 mm or less was deemed to be acceptable. The evaluation results are shown in Tables 1 to 3 below. A preferable result is a case in which the maximum value of the vertical length from the cut edge side in the peeled part is 0.3 mm or less, and more preferably 0.1 mm or less.

(Hot water immersion test)
The polarizing plates P1 to P20 obtained above were cut into a size of 50 mm x 50 mm with a Thomson blade to prepare samples for the hot water immersion test. The samples were immersed in hot water at 60°C and held for 2 hours. The samples were then removed from the hot water and the shrinkage of the polarizer was measured. As shown in FIG. 3(A), the measurement was made from the end of the polarizing plate 8 before the test to the end of the polarizing plate 8 that had shrunk in the stretching direction of the polarizer as shown in FIG. 3(B), and the shrinkage was determined as 9. The higher the adhesiveness of the adhesive or protective layer, the smaller the shrinkage, and the less adhesive the polarizing plate, the larger the shrinkage. As an evaluation criterion, a shrinkage of 2.0 mm or less was considered to be acceptable. The evaluation results are shown in Tables 1 to 3 below. A preferable result is 1.0 mm or less, more preferably 0.5 mm or less, and particularly preferably 0.1 mm or less.

(PET peel strength test)
The polarizing plates P1 to P13 obtained above were cut into 150 mm x 25 mm as samples for measuring peel strength, and the PET film side was fixed to a stainless steel (SUS) plate with double-sided tape. A knife was inserted into the edge so that the polarizer of the polarizing plate and the PET film could be peeled at the interface (adhesive layer) between them, creating a peeling margin. This peeling margin was peeled off using a tensile tester at a peeling angle of 90° and a peeling speed of 300 mm/min, and the peel strength between the polarizer and the PET film (peel strength PET) was measured. The evaluation results are shown in Tables 1 and 2 below. A preferable result is 3 (N/25 mm) or more, and more preferably 5 (N/25 mm) or more.

(COP Peel Strength Test)
The polarizing plates P1 to P13 obtained above were cut into 150 mm x 25 mm samples for measuring peel strength, and the COP film side was fixed to a stainless steel (SUS) plate with double-sided tape. A knife was inserted into the edge to create a peeling margin so that the polarizer of the polarizing plate and the COP film could be peeled at the interface (adhesive layer) between them. This peeling margin was peeled off using a tensile tester at a peeling angle of 90° and a peeling speed of 300 mm/min, and the peel strength (peel strength COP) between the polarizer and the COP film was measured. The evaluation results are shown in Tables 1 and 2 below. A preferable result is 2 (N/25 mm) or more.

[Moisture and heat resistance test]
The polarizing plates P1 to P20 obtained above were cut into a size of 50 mm x 50 mm with a Thomson blade. Next, for the polarizing plates P1 to P13, the COP film side was attached to an alkali-free glass plate (EAGLE XG (registered trademark), manufactured by Corning) via a pressure-sensitive adhesive to prepare a sample for a moist heat resistance test. For the polarizing plates P14 to P20, the protective layer side was attached to an alkali-free glass plate (EAGLE XG (registered trademark), manufactured by Corning) via a pressure-sensitive adhesive to prepare a sample for a moist heat resistance test. Next, these samples for moist heat resistance test were subjected to moist heat treatment by storing them in a thermohygrostat (LH-113, manufactured by Espec Corporation) in a 60 ° C. 95% RH environment for 500 hours. Thereafter, the transmittance and polarization degree of the samples for moist heat resistance test before and after the moist heat treatment were measured by the following method. In addition, the appearance of the samples for moist heat resistance test after the moist heat treatment was confirmed.

(Change in transmittance)
The transmittance (%) of the test sample for resistance to moist heat and moisture test before and after moist heat treatment was measured using an ultraviolet-visible-near infrared spectrophotometer (V7100, manufactured by JASCO Corporation). The value after moist heat treatment was subtracted from the value before moist heat treatment to calculate the change in transmittance (%). The evaluation results are shown in Tables 1 to 3 below. A preferable result is a change in transmittance within ±3%.

(Change in degree of polarization)
The degree of polarization (%) of the moist heat resistance test sample before and after the moist heat treatment was measured using an ultraviolet-visible-near infrared spectrophotometer (V7100, manufactured by JASCO Corporation). The value after the moist heat treatment was subtracted from the value before the moist heat treatment to calculate the change in the degree of polarization (%). The evaluation results are shown in Tables 1 to 3 below. A preferable result is that the change in the degree of polarization is within ±3%.

(exterior)
The appearance of the test sample for resistance to moist heat after the moist heat treatment was visually confirmed and evaluated according to the following criteria. The evaluation results are shown in Tables 1 to 3. A favorable result is an evaluation of A:
Evaluation Criteria
A: Neither lifting of the pressure-sensitive adhesive nor generation of air bubbles was observed.
B: At least one of lifting of the pressure-sensitive adhesive and generation of air bubbles is observed.

[Heat resistance test]
The polarizing plates P1 to P20 obtained above were cut into a size of 50 mm x 50 mm with a Thomson blade. Next, for the polarizing plates P1 to P13, the COP film side was attached to an alkali-free glass plate (EAGLE XG (registered trademark), manufactured by Corning) via a pressure-sensitive adhesive to prepare a heat resistance test sample. For the polarizing plates P14 to P20, the protective layer side was attached to an alkali-free glass plate (EAGLE XG (registered trademark), manufactured by Corning) via a pressure-sensitive adhesive to prepare a heat resistance test sample. Next, these heat resistance test samples were stored in a thermostatic layer (DKN602, manufactured by Yamato Scientific Co., Ltd.) in an 85 ° C. environment for 500 hours to perform a heat treatment. Thereafter, the transmittance and polarization degree of the heat resistance test sample before and after the heat treatment were measured by the following method. In addition, the appearance of the heat resistance test sample after the heat treatment was confirmed.

(Change in transmittance)
The transmittance (%) of the heat resistance test sample before and after the heat treatment was measured using an ultraviolet-visible-near infrared spectrophotometer (V7100, manufactured by JASCO Corporation). The value after the heat treatment was subtracted from the value before the heat treatment to calculate the change in transmittance (%). The evaluation results are shown in Tables 1 to 3 below. A preferable result is that the change in transmittance is within ±3% of the value before the heat treatment.

(Change in degree of polarization)
The heat resistance test sample was measured for the degree of polarization before and after the heat treatment using an ultraviolet-visible-near infrared spectrophotometer (V7100, manufactured by JASCO Corporation). The value after the heat treatment was subtracted from the value before the heat treatment to calculate the change in the degree of polarization (%). The evaluation results are shown in Tables 1 to 3 below. A preferable result is that the change in the degree of polarization is within ±3%.

(exterior)
The appearance of the heat resistance test sample after the heat treatment was visually confirmed and evaluated according to the following criteria. The evaluation results are shown in Tables 1 to 3. A favorable result is an evaluation of A:
Evaluation Criteria
A: Neither lifting of the pressure-sensitive adhesive nor generation of air bubbles was observed.
B: At least one of lifting of the pressure-sensitive adhesive and generation of air bubbles is observed.

[Thermal shock test]
The polarizing plates P1 to P20 obtained above were cut into a size of 50 mm x 50 mm with a Thomson blade to prepare samples for thermal shock testing. Next, as shown in FIG. 4A, the above samples were attached to an alkali-free glass plate (EAGLE XG (registered trademark), Corning) 10 using a non-support tape 11 (CS-9621T, Nitto Denko Corporation), and the test pieces were stored at room temperature (23°C) for 24 hours and subjected to thermal shock testing. The thermal shock testing consisted of 100 cycles of leaving the samples at -40°C for 30 minutes and at 85°C for 30 minutes. Thereafter, the appearance of the samples for thermal shock testing and the polarizer cracking after the thermal shock testing were evaluated by the following method.

(exterior)
The appearance of the thermal shock test sample after the thermal shock test was visually confirmed and evaluated according to the following criteria. The evaluation results are shown in Tables 1 to 3. A favorable result is an evaluation of A:
Evaluation Criteria
A: Neither lifting of the pressure-sensitive adhesive nor generation of air bubbles was observed.
B: At least one of lifting of the pressure-sensitive adhesive and generation of air bubbles is observed.

(Polarizer crack)
After the thermal shock test, the thermal shock test samples were observed to see whether polarizer cracks 12 were present from the end of the polarizing plate in the stretching direction (arrow direction) of the polarizer 1, as shown in Figure 4 (B). If polarizer cracks 12 were observed, the length of the cracks was measured. If multiple cracks were observed, their average value was calculated. The presence or absence of polarizer cracks and their length were evaluated according to the following criteria. The evaluation results are shown in Tables 1 to 3 below. A preferable result is a rating of A or B, and a more preferable result is a rating of A:
Evaluation Criteria
A: No polarizer cracking is observed.
B: Polarizer cracking was confirmed, and the length of the polarizer cracking was less than 0.5 mm.
C: Polarizer cracks were observed, and the length of the polarizer cracks was 0.5 mm or more.

In Table 2 below, "peeling occurred" in the cutting test and hot water immersion test means that at least one of the protective films has completely peeled off. In Table 2 below, "measurement not possible" in the moist heat resistance test, heat resistance test, and thermal shock test means that the test could not be performed because peeling occurred between the test sample and the non-alkali glass plate at at least one of the interfaces between the adhesive layer (pressure-sensitive adhesive layer or non-support tape) and the non-alkali glass, or between the adhesive layer (pressure-sensitive adhesive layer or non-support tape) and the protective film.

<Manufacture and Evaluation of Image Forming Apparatus>
An IPS liquid crystal panel was taken out of a commercially available liquid crystal display device (IPS mode liquid crystal display device), and the polarizing plate on the viewing side attached to the liquid crystal cell of the IPS liquid crystal panel was peeled off. Instead, the polarizing plates P1 to P10 and P14 to P18 according to the present invention were attached to the liquid crystal cell so that the film 4 (PET film, polarizing plate protective film) was the outermost layer on the viewing side of the liquid crystal cell. At this time, the transmission axis direction of the polarizing plate was the same as that of the original polarizing plate. Then, the IPS liquid crystal panel having this liquid crystal cell was returned to its original position. Then, the image quality of the obtained liquid crystal display device was confirmed in a bright room by turning on the backlight. At this time, it was confirmed that the obtained liquid crystal display device had image quality equivalent to that of the original commercially available liquid crystal display device.

First, we will look at the results for the polarizing plate with protective film on both sides.

From Tables 1 and 2 above, it was confirmed that the polarizing plates P1 to P10 manufactured using the curable resin compositions R1 to R10 for polarizing plates according to the present invention as adhesive compositions gave good results in all of the physical property evaluations, moist heat resistance tests, heat resistance tests, and thermal shock tests.

In addition, the curable resin composition for polarizing plates R11 according to the comparative example does not contain the cyclopolymerizable monomer (B). It was confirmed that the polarizing plate P11 produced using the curable resin composition for polarizing plates R11 as an adhesive composition had poor results in the physical property evaluation, the moist heat resistance test, the heat resistance test, and the cold and heat shock test.

The polarizing plate curable resin compositions R12 and R13 according to the comparative examples have a blending amount of cyclopolymerizable monomer (B) outside the range of the present invention. Polarizing plate P12 manufactured using polarizing plate curable resin composition R12 as an adhesive composition peeled off in a cutting test and a hot water immersion test. In addition, due to the ease with which peeling occurred, it was not possible to carry out a moist heat resistance test, a heat resistance test, and a cold and hot shock test. In addition, it was confirmed that polarizing plate P13 manufactured using polarizing plate curable resin composition R13 as an adhesive composition had inferior results in the physical property evaluation, moist heat resistance test, heat resistance test, and cold and hot shock test.

Next, we will look at the results for polarizing plates with a protective film on one side.

From Table 3 above, it was confirmed that polarizing plates P14 to P18, which were manufactured using the curable resin compositions for polarizing plates R14 to R18 according to the present invention as an adhesive composition and a composition for forming a protective layer, gave good results in all of the physical property evaluations, moist heat resistance tests, heat resistance tests, and cold and heat shock tests.

In addition, the curable resin compositions R19 and R20 for polarizing plates according to the comparative examples do not contain the cyclopolymerizable monomer (B). It was confirmed that the polarizing plates P19 and P20 manufactured using the curable resin compositions R19 and R20 for polarizing plates as an adhesive composition and a composition for forming a protective layer had inferior results in the physical property evaluation, heat resistance test, heat resistance test, and thermal shock test.

These results confirmed that the polarizing plate produced using the curable resin composition for polarizing plate according to the present invention as an adhesive composition or a composition for forming a protective layer has excellent adhesion and durability.

1 polarizer,
2. Adhesive composition (curable resin composition for polarizing plate),
2' Composition for forming a protective layer (curable resin composition for polarizing plate),
3. Film (protective film or release film),
4. Film (protective film),
5 Polarizing plate before UV irradiation,
6, 7 rolls,
8 polarizing plate,
9. Magnitude of contraction,
10 glass plate,
11 Non-support tape,
12 Polarizer cracked.

Claims (11)

The present invention comprises an epoxy compound (A), a cyclopolymerizable monomer (B) represented by the following general formula (1) , and a radical polymerizable monomer (C) which does not form a ring structure in the molecule upon radical polymerization ,
The epoxy compound (A) is composed only of a polyfunctional epoxy compound having two or more epoxy groups in one molecule,
The epoxy compound (A) includes an alicyclic epoxy group-containing compound,
The radical polymerizable monomer (C) contains a compound having a cationically polymerizable functional group,
the content of the cyclopolymerizable monomer (B) is 1 part by mass or more and 100 parts by mass or less based on 100 parts by mass of the epoxy compound (A),
At least one condition selected from the group consisting of the following condition (i), the following condition (ii), and the following condition (iii) is satisfied:
Condition (i) The epoxy compound (A) further contains an alicyclic group-containing epoxy group-containing compound;
Condition (ii) the content of the cyclopolymerizable monomer (B) is 10 parts by mass or more and 21.4 parts by mass or less with respect to 100 parts by mass of the epoxy compound (A);
Condition (iii) the content of the cyclopolymerizable monomer (B) is 10 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the epoxy compound (A), and the content of the radical polymerizable monomer (C) is 20 parts by mass or more and 50 parts by mass or less, relative to 100 parts by mass of the epoxy compound (A);
Curable resin composition for optical members.

(In the formula, each R is independently a hydrogen atom or a monovalent organic group,
X ¹ , Y ¹ and Z ¹ each independently represent a methylene group, an oxygen atom, or an imino group;
At least one of X ¹ , Y ¹ and Z ¹ is an oxygen atom or an imino group. 2. The curable resin composition for optical members according to claim 1, wherein a content of the alicyclic epoxy group-containing compound is 40 parts by mass or more based on 100 parts by mass of the epoxy compound (A). 3. The curable resin composition for optical members according to claim 1, wherein, under the condition (i) and the condition (ii), a content of the radical polymerizable monomer (C) is 1 part by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the epoxy compound ( A ). The curable resin composition for optical members according to any one of claims 1 to 3 , further comprising a photoradical polymerization initiator or a photocationic polymerization initiator. The curable resin composition for optical members according to any one of claims 1 to 4, further comprising a photosensitizer. The curable resin composition for optical members according to any one of claims 1 to 5 , which is used for a polarizing plate. A cured product of the curable resin composition for optical members according to any one of claims 1 to 6 . a polarizing film in which iodine or a dichroic dye is adsorbed and oriented in a polyvinyl alcohol-based resin;
A polarizing plate comprising: a protective layer comprising the cured product according to claim 7 or an adhesive layer comprising the cured product according to claim 7 , the protective layer being disposed on at least one surface of the polarizing film. A polarizer and two protective films, wherein one surface of the polarizer and one of the protective films are bonded with an adhesive layer containing the cured product according to claim 7, and the other surface of the polarizer and the other of the protective films are bonded with an adhesive layer containing the cured product according to claim 7.
or
The polarizer includes a polarizer and one protective film, one surface of the polarizer and the protective film are bonded with an adhesive layer containing the cured product according to claim 7, and a protective layer containing the cured product according to claim 7 is disposed so as to be in direct contact with the other surface of the polarizer.
Polarizing plate. 10. The polarizing plate according to claim 8, wherein the adhesive layer or the protective layer has a thickness of 15 μm or less. An image display device comprising the polarizing plate according to any one of claims 8 to 10 .