KR102618402B1 - polarizer - Google Patents

Abstract

Provides a polarizing plate with good optical durability even under high temperature and high humidity environments. A polarizing plate comprising a polarizer and a first cured material layer in this order, wherein the first cured material layer includes an oxazoline group-containing polymer (A), a carboxyl group-containing compound (B), and an oxazoline group-containing polymer (A). A polarizing plate is provided, which is a cured layer of a curable composition containing a compound (C) that promotes the reaction between an oxazoline group and a carboxyl group of the compound (B).

Description

polarizer

The present invention relates to polarizers.

Recently, liquid crystal display devices have been deployed for use in mobile devices, such as smartphones and tablet-type terminals, and in vehicle-mounted devices, such as automobile navigation systems. In these applications, there is a possibility of being exposed to harsh environments compared to conventional indoor TV applications, so improving the durability of the device is an issue.

Durability is similarly required for optical films constituting liquid crystal displays and the like. That is, the optical film inserted into the liquid crystal display device, etc. may be placed in a high temperature or high temperature and high humidity environment, or in an environment where high temperature and low temperature are repeated, and the optical properties are required to not deteriorate even under these environments.

An example of the optical film is a polarizing plate formed by laminating and bonding a thermoplastic resin film, such as a protective film, to one or both sides of a polarizer using an adhesive [e.g., Japanese Patent Application Laid-Open No. 2009-008860 (Patent Document 1)].

Patent Document 1: Japanese Patent Publication No. 2009-008860

The purpose of the present invention is to provide a polarizing plate with good optical durability even under a high temperature and high humidity environment.

The present invention provides a polarizing plate, a curable composition, and a cured product layer shown below.

[1] A polarizing plate comprising a polarizer and a first cured material layer in this order,

The first cured layer is,

Oxazoline group-containing polymer (A) and

Compound (B) having a carboxyl group and

A compound (C) that promotes the reaction between the oxazoline group of the oxazoline group-containing polymer (A) and the carboxyl group of the compound (B)

A polarizing plate that is a cured layer of a curable composition containing a.

[2] The polarizing plate according to [1], wherein the content of compound (B) in the curable composition is 0.01 part by mass or more and 15 parts by mass or less based on 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and compound (B). .

[3] [1] or [2] wherein the content of compound (C) in the curable composition is more than 10 parts by mass and less than or equal to 100 parts by mass based on 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and compound (B). Polarizer described in ].

[4] The polarizing plate according to any one of [1] to [3], wherein the compound (B) has two or more carboxyl groups in the molecule.

[5] The polarizing plate according to any one of [1] to [4], wherein the compound (B) has a molecular weight of 1000 or less.

[6] The polarizing plate according to any one of [1] to [5], comprising the polarizer, the first cured material layer, and the first thermoplastic resin film in this order.

[7] The first thermoplastic resin film is a polarizing plate according to [6] containing at least one thermoplastic resin selected from the group consisting of cellulose ester-based resin, polyester-based resin, (meth)acrylic resin, and cyclic polyolefin-based resin. .

[8] The polarizing plate according to [6] or [7], comprising the second thermoplastic resin film, the second cured material layer, the polarizer, the first cured material layer, and the first thermoplastic resin film in this order.

[9] The polarizing plate according to any one of [1] to [8], wherein the polarizer contains a polyvinyl alcohol-based resin.

[10] A curable composition for adhering a polarizer and a first thermoplastic resin film,

Oxazoline group-containing polymer (A) and

Compound (B) having a carboxyl group and

A compound (C) that promotes the reaction between the oxazoline group of the oxazoline group-containing polymer (A) and the carboxyl group of the compound (B)

A curable composition comprising a.

[11] The curable composition according to [10], wherein the content of compound (B) is 0.01 parts by mass or more and 15 parts by mass or less based on 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and compound (B).

[12] The curable composition according to [10] or [11], wherein the content of compound (C) is more than 10 parts by mass and less than or equal to 100 parts by mass based on 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and compound (B). .

[13] Oxazoline group-containing polymer (A) and

Compound (B) having a carboxyl group and

A compound (C) that promotes the reaction between the oxazoline group of the oxazoline group-containing polymer (A) and the carboxyl group of the compound (B)

A cured layer formed by curing a curable composition containing,

A cured material layer in which the content of compound (C) is more than 10 parts by mass and less than or equal to 100 parts by mass based on 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and compound (B).

It is possible to provide a polarizing plate with good optical durability even under a high temperature and high humidity environment.

1 is a schematic cross-sectional view showing an example of the layer structure of a polarizing plate according to the present invention.
Figure 2 is a schematic cross-sectional view showing another example of the layer structure of a polarizing plate according to the present invention.
Figure 3 is a schematic cross-sectional view showing another example of the layer structure of a polarizing plate according to the present invention.
Figure 4 is a schematic cross-sectional view showing another example of the layer structure of a polarizing plate according to the present invention.
Figure 5 is a schematic cross-sectional view showing another example of the layer structure of a polarizing plate according to the present invention.
Figure 6 is a schematic cross-sectional view showing an example of an optical laminate including a polarizing plate according to the present invention.

<Polarizer>

The polarizing plate according to the present invention includes a polarizer and a first cured material layer in this order. The first cured layer includes an oxazoline group-containing polymer (A), a compound (B) having a carboxyl group (hereinafter also referred to as “compound (B)”), and a compound of the oxazoline group-containing polymer (A). It is a cured layer of a curable composition containing a compound (C) (hereinafter also referred to as “compound (C)”) that promotes the reaction of the carboxyl group of (B).

The polarizing plate according to the present invention can exhibit good optical durability even under high temperature and high humidity environments. Good optical durability refers to the property that the optical properties (such as polarization degree) of a polarizing plate are unlikely to deteriorate even when placed in a high temperature and high humidity environment.

〔1〕 Composition of polarizer

An example of the layer structure of the polarizing plate according to the present invention is shown in FIGS. 1 to 4.

The polarizing plate shown in FIG. 1 includes a polarizer 30 and a first cured material layer 15 laminated on one side of the polarizer 30. The first cured material layer 15 may function as an overcoat layer that covers and protects the surface of the polarizer 30.

It is preferable that the polarizer 30 and the first cured material layer 15 are in direct contact with each other.

The polarizing plate shown in FIG. 2 includes a polarizer 30 and a first thermoplastic resin film 10 that is laminated and bonded to one side of the polarizer through a first cured material layer 15. The first cured material layer 15 may function as an adhesive layer that adheres the polarizer 30 and the first thermoplastic resin film 10.

It is preferable that the first cured material layer 15 and the first thermoplastic resin film 10 are in direct contact with each other.

It is preferable that the polarizer 30 and the first cured material layer 15 are in direct contact with each other.

The polarizing plate shown in FIG. 3 includes a polarizer 30, a first thermoplastic resin film 10 laminated on one side of the polarizer 30 through a first cured material layer 15, and a polarizer 30 on the other side of the polarizer 30. It includes a second thermoplastic resin film 20 that is laminated and bonded to the surface through a second cured material layer 25. That is, the polarizing plate according to the present invention includes a second thermoplastic resin film 20, a second cured material layer 25, a polarizer 30, a first cured material layer 15, and a first thermoplastic resin film 10. It is okay to include them in this order. The first cured material layer 15 and the second cured material layer 25 are adhesive layers for bonding the polarizer 30 and the first thermoplastic resin film 10, respectively, and the polarizer 30 and the second thermoplastic resin film 20 ) can function as an adhesive layer that adheres.

It is preferable that the first cured material layer 15 and the first thermoplastic resin film 10 are in direct contact with each other.

It is preferable that the polarizer 30 and the first cured material layer 15 are in direct contact with each other.

It is preferable that the second cured material layer 25 and the second thermoplastic resin film 20 are in direct contact with each other.

It is preferable that the polarizer 30 and the second cured material layer 25 are in direct contact with each other.

The polarizing plate shown in FIG. 4 includes a polarizer 30, a first cured material layer 15 laminated on one side of the polarizer 30, and a second cured material layer 25 on the other side of the polarizer 30. It includes a second thermoplastic resin film 20 that is laminated and bonded through. The first cured material layer 15 may function as an overcoat layer that covers and protects the surface of the polarizer 30. The second cured material layer 25 may function as an adhesive layer that adheres the polarizer 30 and the second thermoplastic resin film 20.

It is preferable that the polarizer 30 and the first cured material layer 15 are in direct contact with each other.

It is preferable that the second cured material layer 25 and the second thermoplastic resin film 20 are in direct contact with each other.

It is preferable that the polarizer 30 and the second cured material layer 25 are in direct contact with each other.

The polarizing plate shown in FIG. 5 includes a polarizer 30, a first cured material layer 15 laminated on one side of the polarizer 30, and a second cured material layer 25 laminated on the other side of the polarizer 30. ) includes. The first cured material layer 15 and the second cured material layer 25 may function as an overcoat layer that covers and protects the surface of the polarizer 30.

It is preferable that the polarizer 30 and the first cured material layer 15 are in direct contact with each other.

It is preferable that the polarizer 30 and the second cured material layer 25 are in direct contact with each other.

The polarizing plate according to the present invention may include layers (or films) other than those described above. As other layers, for example, on the outer surface of the first thermoplastic resin film 10, the second thermoplastic resin film 20, the first cured material layer 15, the second cured material layer 25, and/or the polarizer 30. A laminated adhesive layer; A separate film (also called “release film”) laminated on the outer surface of this adhesive layer; A protective film ( Also called “surface protection film”); An adhesive layer or pressure-sensitive adhesive layer on the outer surface of the first thermoplastic resin film 10, the second thermoplastic resin film 20, the first cured material layer 15, the second cured material layer 25, and/or the polarizer 30. Examples include optical functional films (or layers) laminated through .

[2] First hardened material layer

The first cured layer 15 is a cured layer of the curable composition (S) containing the oxazoline group-containing polymer (A), the compound (B), and the compound (C).

[2-1] Oxazoline group-containing polymer (A)

The oxazoline group-containing polymer (A) is a polymer having an oxazoline group in the molecule, and is preferably a polymer having an oxazoline group in the side chain.

The skeleton structure of the oxazoline group-containing polymer (A) is not particularly limited, but may include, for example, one or more skeletons selected from (meth)acrylic skeleton, styrene skeleton, olefin skeleton, ester skeleton, carbonate skeleton, etc.

In this specification, “(meth)acrylic” represents at least one type selected from the group consisting of acrylic and methacryl. The same applies to expressions such as “(meth)acryloyl” and “(meth)acrylate.”

The oxazoline group-containing polymer (A) may have an oxazoline group in the side chain of the skeleton structure.

A preferred example of the oxazoline group-containing polymer (A) is a structural unit (derived from an oxazoline group-containing monomer) that contains a skeletal structure containing a (meth)acrylic skeleton as a main component of the structural unit and has an oxazoline group in the side chain as a copolymerization component. It is a (meth)acrylic polymer containing an oxazoline group into which the structural unit of) has been introduced.

The oxazoline group-containing polymer (A) may be one obtained by copolymerizing an oxazoline group-containing monomer or one made to contain an oxazoline group by modifying the side chain functional group of the polymer.

Examples of the oxazoline group include 2-oxazoline group, 3-oxazoline group, and 4-oxazoline group. The oxazoline group is preferably a 2-oxazoline group or the like.

Examples of the oxazoline group-containing monomer include 2-isopropenyl-2-oxazoline, vinyl-2-oxazoline, and the like.

The weight average molecular weight of the oxazoline group-containing polymer (A) is preferably 5000 or more, and more preferably 10000 or more. The weight average molecular weight being within the above range improves the optical durability of the polarizing plate and the adhesion between the polarizer 30 and the first cured material layer 15 or the adhesion between the polarizer 30 and the first thermoplastic resin film 10. This can be beneficial in terms of improvement. The weight average molecular weight of the oxazoline group-containing polymer (A) is usually 1,000,000 (million) or less.

The weight average molecular weight of the oxazoline group-containing polymer (A) can be measured as a standard polystyrene conversion value by gel permeation chromatography (GPC).

The amount of oxazoline groups (number of moles of oxazoline groups per 1 g of solid content of the oxazoline group-containing polymer (A)) of the oxazoline group-containing polymer (A) is preferably 0.4 mmol/g·solid or more. If the amount of oxazoline group is less than the above range, there is a risk that the optical durability of the polarizing plate may decrease. From this viewpoint, the amount of oxazoline group in the oxazoline group-containing polymer is more preferably 3 mmol/g·solid or more, and even more preferably 5 mmol/g·solid or more and 9 mmol/g·solid or less. The upper limit of the amount of oxazoline group is not particularly limited, but is usually 50 mmol/g·solid or less.

The oxazoline group-containing polymer (A) is preferably an aqueous polymer, that is, a water-soluble polymer, or a water-dispersible polymer. From the viewpoint of the optical properties of the first cured layer 15, the oxazoline group-containing polymer (A) is preferably a water-soluble polymer.

The oxazoline group-containing polymer (A) may be a commercially available product. Specifically, oxazoline group-containing acrylic polymers such as Epochros WS-300, Epochros WS-500, and Epochros WS-700 manufactured by Nippon Shokubai Co., Ltd. (all brand names); Examples include acrylic/styrene polymers containing oxazoline groups, such as the Epochros K-1000 series, Epochros K-2000 series, and Epochs RPS series (all brand names) manufactured by Nippon Shokubai Co., Ltd.

Two or more types of oxazoline group-containing polymers (A) can be used in combination.

The optical durability and optical properties of the polarizer, the adhesion between the polarizer 30 and the first cured layer 15 or the adhesion between the polarizer 30 and the first thermoplastic resin film 10, and the first cured layer ( From the viewpoint of water resistance in 15), the oxazoline group-containing polymer (A) is preferably an oxazoline group-containing acrylic polymer such as Epochros WS-300, Epochros WS-500, or Epochros WS-700.

The content of the oxazoline group-containing polymer (A) is preferably 60% by mass or more and 95% by mass or less, more preferably 65% by mass or more and 90% by mass, when the solid content concentration of the curable composition (S) is 100% by mass. % or less, more preferably 70% by mass or more and 85% by mass or less. Keeping the content of the oxazoline group-containing polymer (A) within the above range is determined by the optical durability of the polarizing plate, the adhesion between the polarizer 30 and the first cured material layer 15, and the polarizer 30 and the first thermoplastic resin film. (10) It is preferable from the viewpoint of adhesion between the two.

Solid content concentration refers to the total concentration of components other than the solvent contained in the curable composition (S).

[2-2] Compound (B)

The compound (B) having a carboxyl group is a compound having a carboxyl group that can react with the oxazoline group of the oxazoline group-containing polymer (A). The carboxyl group referred to here also includes derivatives of the carboxyl group.

Derivatives of the carboxyl group include carboxylate anionic groups. Cations that serve as counter ions for carboxylate anion groups include metal ions such as lithium ions, sodium ions, and potassium ions; Organic cations such as ammonium ion, sulfonium ion, and phosphonium ion can be mentioned.

The curable composition (S) may contain one type of compound (B), or may contain two or more types of compounds (B).

Among them, compound (B) is used to improve the optical durability of the polarizing plate, the adhesion between the polarizer 30 and the first cured material layer 15, the adhesiveness between the polarizer 30 and the first thermoplastic resin film 10, and the 1 From the viewpoint of increasing the water resistance of the cured material layer 15, it is preferable that the compound (polyfunctional carboxylic acid compound) has two or more carboxyl groups (or derivatives thereof) in the molecule.

One example of a multifunctional carboxylic acid compound is a dicarboxylic acid compound. Dicarboxylic acid compounds include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, tartaric acid, glutamic acid, malic acid, and maleic acid. , fumaric acid, itaconic acid, muconic acid, 1,4-cyclohexanedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid, 2,5-pyridinedicarboxylic acid, 3,5-pyridinedicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenylmethanedicarboxylic acid, oxalo Acetic acid, methyl fumaric acid, 2,6-pyridinedicarboxylic acid, etc. can be mentioned.

Another example of a multifunctional carboxylic acid compound is a tricarboxylic acid compound. Tricarboxylic acid compounds include citric acid, aconitic acid, propane-1,2,3-tricarboxylic acid, trimellitic acid, trimesic acid, hemimellitic acid, and biphenyl-3,4',5-tricarboxylic acid. Boxylic acid, 1,3,5-cyclohexanetricarboxylic acid, etc. are mentioned.

Another example of a multifunctional carboxylic acid compound is a tetracarboxylic acid compound. Examples of tetracarboxylic acid compounds include pyromellitic acid, diphenylsulfonetetracarboxylic acid, biphenyltetracarboxylic acid, benzophenonetetracarboxylic acid, naphthalenetetracarboxylic acid, thiopentetracarboxylic acid, and butanetetracarboxylic acid. Acid, 1,2,4,5-tetrakis(4-carboxyphenyl)benzene, etc. are mentioned.

In the polyfunctional carboxylic acid compound exemplified above, at least one carboxyl group may be a derivative thereof.

Compound (B) may have a functional group other than the carboxyl group. An example of another functional group is a hydroxy group.

From the viewpoint of the optical durability of the polarizing plate, the number of carboxyl groups that compound (B) has is preferably 2 or 3.

The polyfunctional carboxylic acid compound may be a polymer having two or more carboxyl groups (or derivatives thereof) in the molecule. An example of this polymer is a carboxyl group-modified polymer. An example of a carboxyl group-modified polymer is a carboxyl group-modified polyvinyl alcohol-based polymer.

The carboxyl group-modified polyvinyl alcohol-based polymer is a polyvinyl alcohol-based polymer modified by introducing a carboxyl group or a derivative thereof into the side chain.

Derivatives of the carboxyl group include carboxylate anionic groups. Examples of cations serving as counter ions of the carboxylate anion group are the same as those described above. One example of a preferred cation is sodium ion.

The polyvinyl alcohol-based polymer that constitutes the main chain of the carboxyl group-modified polyvinyl alcohol-based polymer is a vinyl alcohol homopolymer (fully saponified polyvinyl alcohol or partially saponified polyvinyl alcohol) obtained by saponifying polyvinyl acetate, a homopolymer of vinyl acetate. Alternatively, it may be a polyvinyl alcohol-based copolymer obtained by saponifying a copolymer of vinyl acetate and other monomers copolymerizable with vinyl acetate.

Other monomers that can be copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides having an ammonium group.

The degree of saponification of the carboxyl group-modified polyvinyl alcohol-based polymer is usually 80 mol% or more and 100 mol% or less, and is preferably 85 mol% or more (for example, 88 mol% or more).

The degree of saponification of the carboxyl group-modified polyvinyl alcohol-based polymer can be measured according to JIS K 6726:1994.

The degree of modification (amount of modification) of the carboxyl group-modified polyvinyl alcohol-based polymer by the carboxyl group (or its derivative) is usually 0.1 mol% or more. The degree of modification of the carboxyl group-modified polyvinyl alcohol-based polymer is determined by the optical durability of the polarizing plate, the adhesion between the polarizer 30 and the first cured material layer 15, and the adhesion between the polarizer 30 and the first thermoplastic resin film 10. From the viewpoint of improving the stability and water resistance of the first cured layer 15, it is preferably 0.5 mol% or more and 40 mol% or less, and more preferably 1 mol% or more and 20 mol% or less. The degree of denaturation can be measured by, for example ^{, 1} H-NMR.

The average degree of polymerization of the carboxyl group-modified polyvinyl alcohol-based polymer is usually 100 or more and 3000 or less.

The average degree of polymerization of the carboxyl group-modified polyvinyl alcohol-based polymer can be measured according to JIS K 6726:1994.

In one preferred embodiment, compound (B) has a molecular weight of 1000 or less. This molecular weight is the molecular weight calculated from the chemical structural formula, but when compound (B) is a polymer, the number average molecular weight measured as a standard polystyrene conversion value by gel permeation chromatography (GPC) may be used.

Using a compound (B) with a molecular weight of 1000 or less can be advantageous in increasing the optical durability of the polarizing plate. From the viewpoint of optical durability of the polarizing plate, the molecular weight of compound (B) is preferably 800 or less, and more preferably 500 or less.

In addition, the molecular weight of compound (B) determines the optical durability of the polarizing plate, the adhesion between the polarizer 30 and the first cured material layer 15, the adhesion between the polarizer 30 and the first thermoplastic resin film 10, And from the viewpoint of water resistance of the first cured layer 15, it is preferably 90 or more, and more preferably 100 or more.

Compound (B) is preferably citric acid, malic acid, maleic acid or tartaric acid.

The content of compound (B) in the curable composition (S) is preferably 0.01 mass parts out of 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and compound (B) from the viewpoint of increasing the optical durability of the polarizing plate. It is 15 parts by mass or less, more preferably 0.1 parts by mass or more and 12 parts by mass or less, and even more preferably 0.3 parts by mass or more and less than 10 parts by mass.

If the content of compound (B) is excessively small, it is difficult to obtain good optical durability of the polarizing plate.

In addition, when the content of compound (B) is excessively high, the optical durability of the polarizing plate, the adhesion between the polarizer 30 and the first cured material layer 15, and the gap between the polarizer 30 and the first thermoplastic resin film 10 are affected. At least one of the adhesiveness and the water resistance of the first cured layer 15 tends to decrease.

[2-3] Compound (C)

Compound (C) is a compound that promotes the reaction between the oxazoline group of the oxazoline group-containing polymer (A) and the carboxyl group of compound (B). The promotion referred to here also includes initiating the above reaction.

Suitable examples of compound (C) include acid compounds. The acid compound may be a compound that functions as a reaction catalyst between the oxazoline group of the oxazoline group-containing polymer (A) and the carboxyl group of the compound (B).

Examples of the acid compounds include inorganic acids such as sulfuric acid, hydrogen chloride, nitric acid, phosphoric acid, phosphorous acid, and boric acid; Organic acids such as p-toluenesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, methanesulfonic acid, benzenesulfonic acid, phenylphosphoric acid, sulphanilic acid, phenylphosphonic acid, acetic acid, and propionic acid can be mentioned.

The curable composition (S) may contain one type of compound (C) or may contain two or more types of compounds (C).

Compound (C) may be blended into the curable composition (S) as a solution (for example, an aqueous solution) containing compound (C).

Among them, compound (C) improves the optical durability of the polarizer, the adhesion between the polarizer 30 and the first cured material layer 15, and the adhesion between the polarizer 30 and the first thermoplastic resin film 10. From this point of view, it is preferable that it is a relatively strong acid, and examples of such acid compounds include sulfuric acid, hydrogen chloride (hydrochloric acid), nitric acid, and p-toluenesulfonic acid.

When the above strong acid is used as the compound (C), the adhesion between the polarizer 30 and the first cured material layer 15 and the adhesion between the polarizer 30 and the first thermoplastic resin film 10 are improved. It tends to be easy to do.

The content of compound (C) in the curable composition (S) is usually 6 parts by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and compound (B), and is used to determine the optical properties of the polarizing plate. From the viewpoint of durability and improving the adhesion between the polarizer 30 and the first cured material layer 15 or the adhesion between the polarizer 30 and the first thermoplastic resin film 10, preferably 10 parts by mass or more. It is not more than 100 parts by mass, more preferably not less than 10 parts by mass and not more than 100 parts by mass, and even more preferably not less than 15 parts by mass and not more than 100 parts by mass.

In one preferred embodiment, the content of compound (C) is 80 parts by mass or less with respect to 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and compound (B) from the viewpoint of increasing the optical durability of the polarizing plate. .

If the content of compound (C) is excessively small, it is difficult to obtain good optical durability of the polarizing plate.

In addition, if the content of compound (C) is excessively small, the adhesion between the polarizer 30 and the first cured material layer 15 or the adhesion between the polarizer 30 and the first thermoplastic resin film 10 may decrease. It tends to be easy.

When the content of compound (C) is excessively high, the optical durability of the polarizing plate, the adhesion between the polarizer 30 and the first cured material layer 15, and the adhesion between the polarizer 30 and the first thermoplastic resin film 10 are affected. , and at least one of the water resistance properties of the first cured layer 15 tends to deteriorate.

[2-4] Other ingredients

The curable composition (S) may contain other components other than the oxazoline group-containing polymer (A), compound (B), and compound (C).

Other components include curable components and crosslinking agents such as polyhydric aldehydes, melamine-based compounds, zirconia compounds, zinc compounds, aziridine compounds, glyoxal, glyoxal derivatives, and water-soluble epoxy resins; Modified polyvinyl alcohol-based polymers other than carboxyl group-modified polyvinyl alcohol-based polymers; Additives such as coupling agents, tackifiers, antioxidants, ultraviolet absorbers, heat stabilizers, and hydrolysis inhibitors may be included.

The curable composition (S) may contain one or two or more other components.

The curable composition (S) preferably contains a solvent. Solvents include water, organic solvents, and mixtures thereof. The solvent preferably contains water, but water and a water-soluble organic solvent may be used together. Examples of organic solvents include alcohol solvents such as ethanol and 1-methoxy-2-propanol.

It is preferable that the main component of the solvent is water. The main component means that it accounts for 50% by mass or more of the total solvent.

The solid content concentration of the curable composition (S) is usually 0.5 mass% or more and 20 mass% or less, and preferably 1 mass% or more and 15 mass% or less.

The curable composition (S) can function as an adhesive composition. In this case, the curable composition (S) is preferably a water-based adhesive. That is, the curable composition (S) is preferably a solution in which the ingredients are dissolved in a solvent containing water, or a dispersion (for example, an emulsion) in which the ingredients are dispersed in a solvent containing water. Moreover, even when the curable composition (S) is used to form an overcoat layer, the curable composition (S) is a solution in which the compounding ingredients are dissolved in a solvent containing water, or the compounding ingredients are dissolved in a solvent containing water. It is preferable that it is a dispersed dispersion (for example, an emulsion).

The viscosity of the curable composition (S) at 25°C is preferably 50 mPa·sec or less, more preferably 1 mPa·sec or more and 30 mPa·sec or less, and even more preferably 2 mPa·sec or more and 20 mPa·sec or less. do. If the viscosity at 25°C exceeds 50 mPa·sec, it becomes difficult to apply uniformly, which may cause coating unevenness, and problems such as pipe clogging may also occur.

The viscosity of the curable composition (S) at 25°C can be measured with an E-type viscometer.

[3] Polarizer

The polarizer 30 is a film that has the function of selectively transmitting linearly polarized light in one direction from natural light.

Examples of the polarizer 30 include a polarizer containing a polyvinyl alcohol-based resin, and more specifically, a polarizer comprised of a polyvinyl alcohol-based resin film.

As a polarizer composed of a polyvinyl alcohol-based resin film, for example, an iodine-based polarizer in which iodine as a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, and a dichroic dye as a dichroic dye is adsorbed and oriented in a polyvinyl alcohol-based resin film. An oriented dye-based polarizer can be mentioned.

Additionally, the polarizer 30 may be an applied polarizer in which a dichroic dye in a lyotropic liquid crystal state is coated on a base film to orient and fix the dye.

The above polarizer is called an absorption-type polarizer because it selectively transmits linearly polarized light in one direction from natural light and absorbs linearly polarized light in another direction.

The polarizer 30 is not limited to an absorption type polarizer, but is a reflection type polarizer that selectively transmits linearly polarized light in one direction from natural light and reflects linearly polarized light in another direction, or scatters linearly polarized light in another direction. Although a scattering type polarizer may be used, an absorption type polarizer is preferable in that it has excellent visibility.

Among them, a polyvinyl alcohol-based polarizer composed of a polyvinyl alcohol-based resin film is more preferable, and a polyvinyl alcohol-based polarizer in which a dichroic dye such as iodine or a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film is more preferable. It is preferable, and a polyvinyl alcohol-based polarizer in which iodine is adsorbed and oriented on a polyvinyl alcohol-based resin film is particularly preferable.

As the polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based polarizer, saponified polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as copolymers of other monomers that can be copolymerized with vinyl acetate. Other monomers that can be copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides having an ammonium group.

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

The average degree of polymerization of polyvinyl alcohol-based resin can be determined based on JIS K 6726:1994.

A film formed of such a polyvinyl alcohol-based resin is used as a raw film of the polarizer 30 composed of a polyvinyl alcohol-based resin film. The method of forming a polyvinyl alcohol-based resin film is not particularly limited, and a known method is employed.

The thickness of the polyvinyl alcohol-based raw film is, for example, 150 μm or less, preferably 100 μm or less (eg, 50 μm or less), and 5 μm or more.

The polarizer 30 comprised of a polyvinyl alcohol-based resin film includes the process of uniaxially stretching the polyvinyl alcohol-based resin film; A process of adsorbing a dichroic dye by dyeing a polyvinyl alcohol-based resin film with a dichroic dye; A process of treating (crosslinking) a polyvinyl alcohol-based resin film to which a dichroic dye is adsorbed with an aqueous boric acid solution; and a step of washing with water after treatment with an aqueous solution of boric acid.

Uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after dyeing with a dichroic dye. When uniaxial stretching is performed after dyeing, this uniaxial stretching may be performed before or during boric acid treatment. Additionally, uniaxial stretching may be performed in these plural stages.

In uniaxial stretching, the material may be stretched uniaxially between rolls with different circumferential speeds, or it may be stretched uniaxially using thermal rolls. In addition, uniaxial stretching may be dry stretching in which stretching is performed in the air, or wet stretching in which stretching is performed in a state in which the polyvinyl alcohol-based resin film is swollen using a solvent such as water. The stretching ratio is usually 3 times or more and 8 times or less.

A method of dyeing a polyvinyl alcohol-based resin film with a dichroic dye includes, for example, a method of immersing the film in an aqueous solution containing a dichroic dye. Iodine and dichroic organic dyes are used as dichroic dyes. In addition, it is preferable to immerse the polyvinyl alcohol-based resin film in water before dyeing treatment.

Examples of the dyeing treatment method using iodine include a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide. The iodine content in this aqueous solution may be 0.01 part by mass or more and 1 part by mass or less per 100 parts by mass of water. The content of potassium iodide may be 0.5 parts by mass or more and 20 parts by mass or less per 100 parts by mass of water. Additionally, the temperature of this aqueous solution may be 20°C or higher and 40°C or lower.

On the other hand, examples of the dyeing treatment method using a dichroic organic dye include a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic organic dye. The aqueous solution containing the dichroic organic dye may contain an inorganic salt such as sodium sulfate as a dyeing aid. The content of the dichroic organic dye in this aqueous solution may be 1 × 10 ^-4 parts by mass or more and 10 parts by mass or less per 100 parts by mass of water. The temperature of this aqueous solution may be 20°C or higher and 80°C or lower.

Examples of the boric acid treatment method after dyeing with a dichroic dye include a method of immersing the dyed polyvinyl alcohol-based resin film in an aqueous solution containing boric acid. When using iodine as a dichroic dye, it is preferable that the boric acid-containing aqueous solution contains potassium iodide. The amount of boric acid in the boric acid-containing aqueous solution may be 2 parts by mass or more and 15 parts by mass or less per 100 parts by mass of water. The amount of potassium iodide in this aqueous solution may be 0.1 part by mass or more and 20 parts by mass or less per 100 parts by mass of water. The temperature of this aqueous solution may be 50°C or higher, for example, 50°C or higher and 85°C or lower.

The polyvinyl alcohol-based resin film after boric acid treatment is usually washed with water. The water washing treatment can be performed, for example, by immersing the polyvinyl alcohol-based resin film treated with boric acid in water. The temperature of the water in the water washing process is usually 5°C or higher and 40°C or lower. After washing with water, a drying treatment is performed, and the polarizer 30 is obtained.

Drying treatment can be performed using a hot air dryer or far-infrared heater. A polarizing plate can be obtained by forming a cured layer of the curable composition (S) on the surface of the polarizer 30. As described above, the polarizing plate may further include a first thermoplastic resin film 10, a second thermoplastic resin film 20, a second cured material layer, etc.

Additionally, as another example of a method for manufacturing the polarizer 30, for example, the method described in Japanese Patent Application Laid-Open No. 2000-338329 or Japanese Patent Application Laid-Open No. 2012-159778 can be cited. In this method, a solution containing a polyvinyl alcohol-based resin is applied to the surface of the base film to form a resin layer, and then the laminated film consisting of the base film and the resin layer is stretched, followed by dyeing treatment, cross-linking treatment, etc. Thus, a polarizer layer (polarizer 30) is formed with the resin layer. After bonding the first thermoplastic resin film 10 as a protective film or the like to the surface of the polarizer layer of this polarizing laminated film composed of a base film and a polarizer layer through the curable composition (S), the base film is peeled and removed, and It can be used as a polarizing plate having the configuration shown in 2. When the second thermoplastic resin film 20 is further bonded to the surface of the polarizer layer exposed by peeling of the base film through the curable composition, it becomes a polarizing plate with the structure shown in FIG. 3.

The thickness of the polarizer 30 can be 40 μm or less, and is preferably 30 μm or less (for example, 20 μm or less, further 15 μm or less, further 10 μm or less, or 8 μm or less). According to the method described in Japanese Patent Laid-Open No. 2000-338329 or Japanese Patent Laid-Open No. 2012-159778, the thin film polarizer 30 can be more easily manufactured, and the thickness of the polarizer 30 can be, for example, 20 μm or less. It is easier to set it to 15 ㎛ or less, and further to 10 ㎛ or less, or 8 ㎛ or less. The thickness of the polarizer 30 is usually 2 μm or more. Reducing the thickness of the polarizer 30 is advantageous for reducing the thickness of the polarizing plate and, by extension, the image display device.

[4] Thermoplastic resin film

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 are each made of a light-transmitting (preferably optically transparent) thermoplastic resin, such as chain polyolefin resin (polypropylene resin, etc.), cyclic polyolefin resin. Polyolefin-based resins such as (norbornene-based resins, etc.); Cellulose ester-based resins such as triacetyl cellulose and diacetyl cellulose; Polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polycarbonate-based resin; (meth)acrylic resin; Or it may be a film made of a mixture or copolymer thereof.

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be either an unstretched film or a uniaxially or biaxially stretched film. The biaxial stretching may be simultaneous biaxial stretching in which the material is stretched simultaneously in two stretching directions, or may be sequential biaxial stretching in which the material is stretched in a first direction and then stretched in a second direction different from this.

The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may be a protective film that serves to protect the polarizer 30, or may be a protective film that also has an optical function such as a retardation film. there is.

The retardation film is an optical functional film used for the purpose of compensating for the retardation caused by a liquid crystal cell, which is an image display element. For example, a retardation film with an arbitrary retardation value can be obtained by stretching the film made of the thermoplastic resin (uniaxial stretching, biaxial stretching, etc.) or forming a liquid crystal layer on the thermoplastic resin film.

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

Cyclic polyolefin resin is a general term for resins containing cyclic olefins such as norbornene, tetracyclododecene (alias: dimethanooctahydronaphthalene) or their derivatives as polymerized units. As cyclic polyolefin-based resins, ring-opening (co)polymers of cyclic olefins and their hydrogenated products, addition polymers of cyclic olefins, copolymers of cyclic olefins with chain olefins such as ethylene and propylene or aromatic compounds having a vinyl group, and unsaturated carboxylic acids thereof. Modified (co)polymers modified with boxylic acid or its derivatives can be mentioned.

Among them, norbornene-based resins using norbornene-based monomers such as norbornene and polycyclic norbornene-based monomers as cyclic olefins are preferably used.

The cellulose ester-based resin is a resin in which at least part of the hydroxyl group in cellulose is esterified with acetic acid, and may be a mixed ester in which a part is esterified with acetic acid and a part is esterified with another acid. The cellulose ester-based resin is preferably an acetylcellulose-based resin.

Examples of the acetylcellulose-based resin include triacetylcellulose, diacetylcellulose, cellulose acetate propionate, and cellulose acetate butyrate.

Polyester-based resin is a resin other than the above cellulose ester-based resin that has an ester bond, and is generally composed of a polycondensate of polyhydric carboxylic acid or its derivative and polyhydric alcohol.

Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethyl terephthalate, and polycyclohexanedimethyl naphthalate. etc. can be mentioned.

Among them, polyethylene terephthalate is preferably used from the viewpoint of mechanical properties, solvent resistance, scratch resistance, cost, etc. Polyethylene terephthalate refers to a resin in which 80 mol% or more of the repeating units are comprised of ethylene terephthalate, and may also contain structural units derived from other copolymerization components.

Other copolymerization components include dicarboxylic acid components and diol components.

As dicarboxylic acid components, isophthalic acid, 4,4'-dicarboxydiphenyl, 4,4'-dicarboxybenzophenone, bis(4-carboxyphenyl)ethane, adipic acid, sebacic acid, and 5-sodium alcohol. Poisophthalic acid, 1,4-dicarboxycyclohexane, etc. can be mentioned.

Examples of diol components include propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

The dicarboxylic acid component and diol component may be used in combination of two or more types, respectively, as needed.

In addition, it is also possible to use hydroxycarboxylic acids such as p-hydroxybenzoic acid, p-hydroxyethoxybenzoic acid, and β-hydroxyethoxybenzoic acid in combination with the dicarboxylic acid component or diol component.

As other copolymerization components, a small amount of a dicarboxylic acid component and/or a diol component having an amide bond, urethane bond, ether bond, carbonate bond, etc. may be used.

Polycarbonate-based resin is a polyester formed from carbonic acid and glycol or bisphenol. Among them, aromatic polycarbonate having diphenylalkane in the molecular chain is preferably used from the viewpoints of heat resistance, weather resistance, and acid resistance.

Polycarbonates include 2,2-bis(4-hydroxyphenyl)propane (aka bisphenol A), 2,2-bis(4-hydroxyphenyl)butane, and 1,1-bis(4-hydroxyphenyl)cyclohexane. , 1,1-bis(4-hydroxyphenyl)isobutane, and 1,1-bis(4-hydroxyphenyl)ethane.

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

Examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, n-, i- or t-butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, and 2-ethyl methacrylate. Hexyl, 2-hydroxyethyl methacrylate, etc. are mentioned.

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

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

In one preferred embodiment, the (meth)acrylic resin contains methyl methacrylate as a copolymerization component or contains methyl methacrylate and methyl acrylate.

In one preferred embodiment, the (meth)acrylic resin may be a polymer containing methacrylic acid ester as the main monomer (containing 50% by mass or more), and is a copolymer in which methacrylic acid ester and other copolymerization components are copolymerized. It is desirable.

As copolymerization components other than the above-mentioned acrylic acid ester, for example,

2-(hydroxymethyl)methyl acrylate, 2-(1-hydroxyethyl)methyl acrylate, 2-(hydroxymethyl)ethyl acrylate, n-, i- or t-butyl 2-(hydroxymethyl)acrylate, etc. hydroxyalkyl acrylic acid esters;

unsaturated acids such as methacrylic acid and acrylic acid;

Halogenated styrenes such as chlorostyrene and bromostyrene;

Substituted styrenes such as vinyl toluene and α-methylstyrene;

Unsaturated nitriles such as acrylonitrile and methacrylonitrile;

unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride;

Unsaturated imides such as phenylmaleimide and cyclohexylmaleimide;

Monofunctional monomers such as these can be mentioned.

As for the above-mentioned other monofunctional monomers, only one type may be used individually, or two or more types may be used in combination.

A polyfunctional monomer may be used as the other copolymerization component.

Examples of multifunctional monomers include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, nonaethylene glycol di( Esterification of both terminal hydroxyl groups of ethylene glycol or its oligomer with (meth)acrylic acid, such as meth)acrylate and tetradecaethylene glycol di(meth)acrylate;

A product obtained by esterifying both terminal hydroxyl groups of propylene glycol or its oligomer with (meth)acrylic acid;

Products obtained by esterifying the hydroxyl group of a dihydric alcohol such as neopentyl glycol di(meth)acrylate, hexanediol di(meth)acrylate, and butanediol di(meth)acrylate with (meth)acrylic acid;

Bisphenol A, alkylene oxide adducts of bisphenol A, or halogen-substituted products thereof obtained by esterifying both terminal hydroxyl groups with (meth)acrylic acid;

Those obtained by esterifying polyhydric alcohols such as trimethylolpropane and pentaerythritol with (meth)acrylic acid, and those obtained by ring-opening addition of the epoxy groups of glycidyl (meth)acrylate to these terminal hydroxyl groups;

ring-opening addition of the epoxy group of glycidyl (meth)acrylate to dibasic acids such as succinic acid, adipic acid, terephthalic acid, phthalic acid, halogen-substituted products thereof, or alkylene oxide adducts thereof;

Aryl (meth)acrylate; Aromatic divinyl compounds such as divinylbenzene;

etc. can be mentioned.

Among them, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and neopentyl glycol dimethacrylate are preferably used.

The (meth)acrylic resin may be one modified by a reaction between the functional groups of the copolymer. This reaction includes, for example, demethanol condensation reaction within the polymer chain between the methyl ester group of methyl (meth)acrylate and the hydroxyl group of 2-(hydroxymethyl)methyl acrylate, and the carboxyl group of (meth)acrylic acid and 2-(hydroxymethyl ) Dehydration condensation reaction within the polymer chain with the hydroxyl group of methyl acrylate, etc.

The glass transition temperature of the (meth)acrylic resin is preferably 80°C or higher and 160°C or lower. The glass transition temperature is determined by adjusting the polymerization ratio of the methacrylic acid ester monomer and the acrylic acid ester monomer, the carbon chain length of each ester group and the type of functional group they have, and the polymerization ratio of the multifunctional monomer to the entire monomer. It can be controlled by

As a means to increase the glass transition temperature of (meth)acrylic resin, it is also effective to introduce a ring structure into the main chain of the polymer. The ring structure is preferably a heterocyclic structure such as a cyclic acid anhydride structure, a cyclic imide structure, and a lactone structure. Specifically, cyclic acid anhydride structures such as glutaric anhydride structure and succinic anhydride structure; Cyclic imide structures such as glutarimide structure and succinimide structure; Lactone ring structures such as butyrolactone and valerolactone can be mentioned.

As the content of the ring structure in the main chain increases, the glass transition temperature of the (meth)acrylic resin tends to be increased.

A method of introducing the cyclic acid anhydride structure and the cyclic imide structure by copolymerizing monomers having a cyclic structure such as maleic anhydride and maleimide; A method of introducing a cyclic acid anhydride structure through dehydration/demethanol condensation reaction after polymerization; It can be introduced by a method such as reacting an amino compound to introduce a cyclic imide structure.

The resin (polymer) having a lactone ring structure is prepared by preparing a polymer having hydroxyl and ester groups in the polymer chain, then heating the hydroxyl and ester groups in the obtained polymer and, if necessary, using a catalyst such as an organic phosphorus compound. It can be obtained by cyclocondensation in the presence of to form a lactone ring structure.

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

These additives can also be used when thermoplastic resins other than (meth)acrylic resins are used as thermoplastic resins constituting the thermoplastic resin film.

The (meth)acrylic resin may contain acrylic rubber particles, which are impact modifiers, from the viewpoint of film forming properties on the film and impact resistance of the film. Acrylic rubber particles are particles containing an elastic polymer mainly composed of acrylic acid ester as an essential component, and include those having a single-layer structure substantially composed only of this elastic polymer, and those having a multi-layer structure with this elastic polymer as one layer. there is.

Examples of the elastic polymer include a crosslinked elastic copolymer made by copolymerizing alkyl acrylate as a main component with other copolymerizable vinyl monomers and crosslinkable monomers.

Examples of alkyl acrylate, which is the main component of the elastic polymer, include those with an alkyl group having 1 to 8 carbon atoms, such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and alkyl acrylate having an alkyl group with 4 or more carbon atoms. This is preferably used.

Other vinyl monomers copolymerizable with the alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, and more specifically, methacrylic acid esters such as methyl methacrylate; Aromatic vinyl compounds such as styrene; Vinyl cyan compounds such as acrylonitrile, etc. can be mentioned.

Examples of the crosslinkable monomer include crosslinkable compounds having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, ethylene glycol di(meth)acrylate, butanediol di(meth)acrylate, etc. (meth)acrylates of polyhydric alcohols; Alkenyl esters of (meth)acrylic acid such as allyl (meth)acrylate; Divinylbenzene, etc. can be mentioned.

A laminated body of a film made of (meth)acrylic resin containing no rubber particles and a film made of (meth)acrylic resin containing rubber particles can also be used as a thermoplastic resin film bonded to the polarizer 30. In addition, a (meth)acrylic resin layer is formed on one or both sides of a retardation expression layer made of a resin different from the (meth)acrylic resin, and a retardation expression is formed. This can be used as a thermoplastic resin film to be bonded to the polarizer 30. .

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 are each made of at least one thermoplastic resin selected from the group consisting of cellulose ester resin, polyester resin, (meth)acrylic resin, and cyclic polyolefin resin. It is preferable that it is a film containing, and it is more preferable that it is a cellulose ester-based resin film, a polyester-based resin film, a (meth)acrylic-based resin film, or a cyclic polyolefin-based resin film.

The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may contain an ultraviolet absorber. When applying a polarizing plate to an image display device such as a liquid crystal display device, deterioration of the image display device due to ultraviolet rays can be suppressed by placing a thermoplastic resin film containing an ultraviolet absorber on the viewing side of the image display device (e.g., a liquid crystal cell). You can.

Examples of ultraviolet absorbers include salicylic acid ester-based compounds, benzophenone-based compounds, benzotriazole-based compounds, cyanoacrylate-based compounds, and nickel complex salt-based compounds.

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be films made of the same thermoplastic resin, or may be films made of different thermoplastic resins. The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be the same or different in thickness, presence or absence of additives and their types, retardation characteristics, etc.

The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 has a hard coat layer, an anti-glare layer, an anti-reflection layer, a light diffusion layer, and an anti-static layer on its outer surface (the surface opposite to the polarizer 30). It may be provided with a surface treatment layer (coating layer) such as an antifouling layer or a conductive layer.

The thickness of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is usually 5 ㎛ or more and 200 ㎛ or less, respectively, preferably 10 ㎛ or more and 120 ㎛ or less, more preferably 10 ㎛ or more and 85 ㎛ or less. , more preferably 15 ㎛ or more and 65 ㎛ or less. The thickness of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 may each be 50 μm or less, and may be 40 μm or less. Reducing the thickness of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is advantageous for reducing the thickness of the polarizing plate and, by extension, the image display device.

On the surface where the curable composition of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is applied, surface modification treatment such as saponification treatment, plasma treatment, corona treatment, primer treatment, etc. is performed from the viewpoint of improving adhesion. Alternatively, from the viewpoint of process simplification, it is not necessary to perform surface modification treatment. The surface modification treatment may be performed on the bonding surface of the polarizer 30 instead of or together with the bonding surface of the thermoplastic resin film.

When the first thermoplastic resin film 10 or the second thermoplastic resin film 20 is a cellulose ester-based resin film, it is preferable to perform saponification treatment from the viewpoint of improving adhesion. Saponification treatment includes immersion in an aqueous alkali solution such as sodium hydroxide or potassium hydroxide.

[5] Second hardened material layer

The curable composition forming the second cured layer 25 may be the curable composition (S) described above or may be a different curable composition. The second cured layer 25 is preferably a cured layer of the curable composition (S) from the viewpoint of optical durability of the polarizing plate and the like.

When the first cured layer 15 and the second cured layer 25 are formed from the curable composition (S), these curable compositions may have the same composition or different compositions.

Other curable compositions include known water-based adhesives in which a curable adhesive component is dissolved or dispersed in water, and known active energy ray-curable adhesives containing an active energy ray-curable compound.

Examples of the water-based adhesive include water-based adhesives in which adhesive components such as polyvinyl alcohol-based resin and urethane resin are dissolved or dispersed in water.

Water-based adhesives containing polyvinyl alcohol-based resins contain curable components and crosslinking agents such as polyvalent aldehydes, melamine-based compounds, zirconia compounds, zinc compounds, glyoxal, glyoxal derivatives, and water-soluble epoxy resins in order to improve adhesiveness. can do.

Examples of the water-based adhesive containing a urethane resin include a water-based adhesive containing a polyester-based ionomer type urethane resin and a compound having a glycidyloxy group. A polyester-based ionomer type urethane resin is a urethane resin having a polyester skeleton, into which a small amount of ionic component (hydrophilic component) is introduced.

An active energy ray-curable adhesive is an adhesive that hardens by irradiation of active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays. When using an active energy ray-curable adhesive, the second cured layer 25 is a cured layer of the adhesive.

The active energy ray-curable adhesive may be an adhesive that contains an epoxy-based compound that cures by cationic polymerization as a curable component, and is preferably an ultraviolet-curable adhesive that contains this epoxy-based compound as a curable component. An epoxy-based compound refers to a compound having an average of one or more, preferably two or more, epoxy groups in the molecule. Only one type of epoxy-based compound may be used, or two or more types may be used in combination.

Examples of the epoxy compound include hydrogenated epoxy compounds obtained by reacting epichlorohydrin with an alicyclic polyol obtained by hydrogenating the aromatic ring of an aromatic polyol (glycidyl ether of a polyol having an alicyclic ring); Aliphatic epoxy-based compounds such as polyglycidyl ethers of aliphatic polyhydric alcohols or their alkylene oxide adducts; and alicyclic epoxy-based compounds, which are epoxy-based compounds having one or more epoxy groups bonded to an alicyclic ring in the molecule.

The active energy ray-curable adhesive may contain a radically polymerizable (meth)acrylic compound as a curable component instead of or together with the epoxy compound. Examples of (meth)acrylic compounds include (meth)acrylate monomers having one or more (meth)acryloyloxy groups in the molecule; It is obtained by reacting two or more types of functional group-containing compounds, and includes (meth)acryloyloxy group-containing compounds such as (meth)acrylate oligomers having at least two (meth)acryloyloxy groups in the molecule.

When the active energy ray-curable adhesive contains an epoxy-based compound that hardens by cationic polymerization as a curing component, it is preferable to contain a photocationic polymerization initiator. Examples of photocationic polymerization initiators include aromatic diazonium salts; Onium salts such as aromatic iodonium salts and aromatic sulfonium salts; An iron-allene complex, etc. can be mentioned.

When the active energy ray-curable adhesive contains a radical polymerizable component such as a (meth)acrylic compound, it is preferable to contain a radical photopolymerization initiator. Examples of radical photopolymerization initiators include acetophenone-based initiators, benzophenone-based initiators, benzoin ether-based initiators, thioxanthone-based initiators, xanthone, fluorenone, camphorquinone, benzaldehyde, and anthraquinone.

The polarizing plate may include an adhesive layer instead of the second cured material layer 25. That is, the second thermoplastic resin film 20 may be bonded to the polarizer 30 through an adhesive layer. Regarding this adhesive layer, the description regarding the adhesive layer described later is cited.

[6] Manufacturing of polarizer

By laminating and adhering the first thermoplastic resin film 10 to one side of the polarizer 30 through the first cured material layer 15, a polarizing plate having the configuration shown in FIG. 2 can be obtained, and the other side of the polarizer 30 A polarizing plate having the structure shown in FIG. 3 can be obtained by further laminating and adhering the second thermoplastic resin film 20 to the other side through the second cured material layer 25.

When manufacturing a polarizing plate having both the first thermoplastic resin film 10 and the second thermoplastic resin film 20, these films may be laminated and bonded one side at a time, or the films on both sides may be laminated and bonded simultaneously.

As a method of adhering the polarizer 30 and the first thermoplastic resin film 10, the curable composition (S) is applied to one or both of the bonding surfaces of the polarizer 30 and the first thermoplastic resin film 10. , a method of laminating another bonding surface on top of this and bonding them by pressing them from top and bottom using, for example, a bonding roll.

For coating the curable composition (S), various coating methods can be used, such as a doctor blade, wire bar, die coater, comma coater, or gravure coater. Additionally, a method may be used in which the polarizer 30 and the first thermoplastic resin film 10 are continuously supplied so that their bonding surfaces are inside, and the curable composition (S) is cast in the meantime.

After bonding the polarizer 30 and the first thermoplastic resin film 10, heat treatment is performed on the laminate including the polarizer 30, the first cured material layer 15, and the first thermoplastic resin film 10. It is desirable to implement it. The temperature of the heat treatment is, for example, 40°C or higher and 100°C or lower, and is preferably 50°C or higher and 90°C or lower. The solvent contained in the curable composition layer can be removed by heat treatment. Additionally, the curing/crosslinking reaction of the curable composition can be promoted by this heat treatment.

The above adhesion method can also be applied to adhesion between the polarizer 30 and the second thermoplastic resin film 20.

When using an active energy ray-curable adhesive, after drying the curable composition layer as needed, the curable composition layer is cured by irradiating active energy rays.

The light source used to irradiate active energy rays may be any that can generate ultraviolet rays, electron rays, X-rays, etc. In particular, 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 in a wavelength of 400 nm or less, are suitably used.

A polarizing plate as shown in FIG. 1 that does not have a first thermoplastic resin film on the first cured layer 15 is a laminate obtained by coating the curable composition (S) on the surface of the polarizer 30. , for example, can be produced by heat treatment at 80°C for 300 seconds using a hot air dryer.

In addition, the polarizing plate shown in FIG. 1 can also be manufactured by manufacturing a laminate consisting of the separate film/curable composition (S)/polarizer 30, peeling the separate film, and then performing heat treatment. .

The thickness of the first cured material layer 15 formed from the curable composition (S) is, for example, 1 nm or more and 20 μm or less, preferably 5 nm or more and 10 μm or less, and more preferably 10 nm or more and 5 μm or less. And, more preferably, it is 20 nm or more and 1 ㎛ or less. The adhesive layer formed from the above-mentioned known water-based adhesive may also have a thickness similar to this.

The thickness of the adhesive layer formed from the active energy ray-curable adhesive is, for example, 10 nm or more and 20 μm or less, preferably 100 nm or more and 10 μm or less, and more preferably 500 nm or more and 5 μm or less.

The first cured layer 15 and the second cured layer 25 may have the same or different thicknesses.

[7] Other components of the polarizer

[7-1] Optical functional film

The polarizing plate may be equipped with an optical functional film other than the polarizer 30 to provide a desired optical function, and a suitable example is a retardation film.

As described above, the first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may also serve as a retardation film, but a retardation film may be laminated separately from these films. In the latter case, the retardation film is connected to the first thermoplastic resin film 10, the second thermoplastic resin film 20, the first cured material layer 15, and/or the second cured material layer ( 25) can be laminated on the outer surface.

Examples of the retardation film include a birefringent film made of a stretched film of a light-transmitting thermoplastic resin; A film in which discotic liquid crystal or nematic liquid crystal is aligned and fixed; Examples include those in which the above-mentioned liquid crystal layer is formed on a base film.

The base film is usually a film made of a thermoplastic resin, and an example of the thermoplastic resin is a cellulose ester-based resin such as triacetylcellulose.

Examples of other optical functional films (optical members) that can be included in the polarizing plate include a light collection plate, a brightness enhancing film, a reflective layer (reflective film), a transflective reflective layer (transflective reflective film), and a light diffusion layer (light diffusion film). These are generally formed when the polarizing plate is a polarizing plate disposed on the backside (backlight side) of the liquid crystal cell.

The light collecting plate is used for purposes such as light path control, and may be a prism array sheet, a lens array sheet, or a dot laying sheet.

A brightness improving film is used for the purpose of improving the brightness in a liquid crystal display device to which a polarizing plate is applied. Specifically, a reflective polarized light separation sheet designed to create anisotropy in reflectance by stacking several thin films with different anisotropies of refractive index, and an orientation film of cholesteric liquid crystal polymer or an orientation liquid crystal layer thereof supported on a base film. Circularly polarized light separation sheets, etc. can be mentioned.

The reflective layer, the semi-transmissive reflective layer, and the light diffusion layer are respectively provided to make the polarizing plate into a reflective, transflective, or diffusion-type optical member. A reflective polarizing plate is used in a type of liquid crystal display device that displays by reflecting incident light from the viewer's side, and a light source such as a backlight can be omitted, making it easy to make the liquid crystal display device thinner. A semi-transmissive polarizer is used in a liquid crystal display device that is reflective in a bright place and displays with light from a backlight in a dark place. Additionally, a diffusion type polarizing plate is used in a liquid crystal display device that suppresses display defects such as moire by providing light diffusion properties. The reflective layer, semi-transmissive reflective layer, and light diffusion layer can be formed by known methods.

[7-2] Adhesive layer

The polarizing plate according to the present invention may include an adhesive layer. Examples of the adhesive layer include an adhesive layer for bonding a polarizing plate to an image display element such as a liquid crystal cell or another optical member. This pressure-sensitive adhesive layer is on the outer surface of the polarizer 30 in the polarizing plate with the configuration shown in FIGS. 1 and 2, and on the first thermoplastic resin film 10 or the second thermoplastic resin film ( 20), the outer surface of the first cured layer 15 or the second thermoplastic resin film 20 in the polarizing plate having the configuration shown in FIG. 4, and the first cured material layer in the polarizing plate having the configuration shown in FIG. 5. (15) Alternatively, it can be laminated on the outer surface of the second cured material layer (25).

As the adhesive used in the adhesive layer, one whose base polymer is (meth)acrylic resin, silicone resin, polyester resin, polyurethane resin, polyether resin, etc. can be used. Among them, (meth)acrylic adhesives are preferable from the viewpoints of transparency, adhesiveness, reliability, weather resistance, heat resistance, reworkability, etc.

(meth)acrylic adhesives include (meth)acrylic acid alkyl esters having an alkyl group with 20 or less carbon atoms such as a methyl group, ethyl group, n-, i-, or t-butyl group, and (meth)acrylic acid or hydroxyethyl (meth)acrylate. A (meth)acrylic resin with a weight average molecular weight of 100,000 or more, which is blended with functional group-containing (meth)acrylic monomers such as the like so that the glass transition temperature is preferably 25°C or lower, more preferably 0°C or lower, is used as the base polymer. useful.

The formation of the adhesive layer on the polarizing plate is, for example, a method of dissolving or dispersing the adhesive composition in an organic solvent such as toluene or ethyl acetate to prepare an adhesive solution and applying this directly to the target surface of the polarizing plate to form the adhesive layer. This can be done by forming an adhesive layer in the form of a sheet on the treated separate film and transferring it to the target surface of the polarizing plate.

The thickness of the adhesive layer is determined depending on its adhesive strength, etc., but is suitably in the range of 1 µm to 50 µm, and is preferably 2 µm to 40 µm.

The polarizing plate may include the above-described separate film. The separate film may be a film made of a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, or a polyester-based resin such as polyethylene terephthalate. Among these, stretched films of polyethylene terephthalate are preferable.

The adhesive layer may include fillers made of glass fibers, glass beads, resin beads, metal powders or other inorganic powders, pigments, colorants, antioxidants, ultraviolet absorbers, antistatic agents, etc., as needed.

[7-3] Protective film

The polarizing plate according to the present invention has a surface (typically the first thermoplastic resin film 10, the second thermoplastic resin film 20, the first cured layer 15, and/or the second cured layer 25). may include a protective film to protect the surface. The protective film is peeled and removed for each adhesive layer it has, for example, after the polarizing plate is bonded to the image display element or other optical member.

The protective film is comprised, for example, of a base film and an adhesive layer laminated thereon. Regarding the adhesive layer, the above-described technical content is cited.

The resin constituting the base film may be, for example, a thermoplastic resin such as a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, a polyester-based resin such as polyethylene terephthalate or polyethylene naphthalate, or a polycarbonate-based resin. . Preferably it is a polyester-based resin such as polyethylene terephthalate.

<Liquid crystal panel and liquid crystal display device>

The polarizing plate according to the present invention can be used in liquid crystal panels and liquid crystal display devices. The liquid crystal panel includes a liquid crystal cell and a polarizing plate disposed on both sides of the liquid crystal cell. A liquid crystal display device includes a liquid crystal panel and a backlight.

The polarizing plate according to the present invention can be placed on one or both sides of the liquid crystal cell. An adhesive layer can be used to bond a polarizer and a liquid crystal cell.

An example of an optical laminate in which a polarizing plate is laminated on a liquid crystal cell through an adhesive layer is shown in Figure 6.

The optical laminate shown in FIG. 6 is one in which the polarizing plate shown in FIG. 3 is laminated on one side of a liquid crystal cell 50 through an adhesive layer 40, and includes a first thermoplastic resin film 10 and a first mirror. It includes a cargo layer 15, a polarizer 30, a second cured material layer 25, a second thermoplastic resin film 20, an adhesive layer 40, and a liquid crystal cell 50 in this order. Regarding the adhesive layer 40, the above-described technical content regarding the adhesive layer is cited.

The liquid crystal cell may be any type. For example, various liquid crystal cells, such as an active matrix driven liquid crystal cell represented by a thin film transistor type and a simple matrix driven liquid crystal cell represented by a super twisted nematic type, can be used to form a liquid crystal panel and liquid crystal. A display device can be formed. The polarizing plates installed on both sides of the liquid crystal cell may be the same or different.

[Example]

Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. In the examples, % and parts indicating content or usage are based on mass, unless otherwise specified.

In Table 1, the oxazoline group-containing polymer (A), the compound (B) having a carboxyl group, and the compound (C) that promotes the reaction between the oxazoline group of the oxazoline group-containing polymer (A) and the carboxyl group of compound (B) are They are abbreviated as (A), (B), and (C), respectively.

(Manufacturing example: Production of polarizer)

A polyvinyl alcohol film with a thickness of 60 ㎛ (average degree of polymerization: about 2,400, degree of saponification: 99.9 mol% or more) was immersed in pure water at 30°C, and then soaked in pure water at 30°C with a mass ratio of iodine/potassium iodide/water of 0.02/2/100. immersed in an aqueous solution. After that, it was immersed in an aqueous solution at 56.5°C with a mass ratio of potassium iodide/boric acid/water of 12/5/100. Subsequently, after washing with pure water at 8°C, it was dried at 65°C to obtain a polarizer with a thickness of 23 μm in which iodine was adsorbed and oriented on a polyvinyl alcohol film. Stretching was mainly performed in the steps of iodine dyeing and boric acid treatment, and the total stretching ratio was 5.5 times.

<Examples 1 to 12, Comparative Examples 1 to 5>

(1) Preparation of curable composition

The components shown in Table 1 were mixed in the amounts shown in Table 1 with pure water as a solvent to prepare a curable composition (adhesive aqueous solution). The unit of the compounding amount of each component shown in Table 1 is mass part, and the compounding amount of each component is the amount converted to solid content. In each Example and Comparative Example, the total concentration of (A) and (B) in the obtained curable composition was 3.0 mass%.

(2) Production of polarizer

After saponification treatment was performed on one side of a triacetylcellulose (TAC) film [trade name "KC4UAW" manufactured by Konica Minolta Opd Co., Ltd., thickness: 40 ㎛], the curable composition prepared in (1) above was applied to the saponification treatment side. In addition to coating using a bar coater, corona treatment was performed on one side of a 23 ㎛ thick zero retardation film made of cyclic polyolefin resin (trade name "ZEONOR" manufactured by Nippon Zeon Co., Ltd.), and the corona-treated side was The curable composition prepared in (1) above was applied using a bar coater. A saponified TAC film is laminated on one side of the polarizer so that the curable composition layer is on the polarizer side, and a zero retardation film is laminated on the other side, so that the zero retardation film/curable composition layer/polarizer/curable composition layer/TAC film is laminated. A laminate having a layer structure was obtained. This laminate was subjected to heat treatment at 80°C for 300 seconds using a hot air dryer to produce a polarizing plate having a layer structure of zero retardation film/cured material layer/polarizer/cured material layer/TAC film. The thickness of the cured layer of the produced polarizing plate was 20 to 60 nm per layer.

(3) Evaluation of optical durability

The obtained polarizing plate was cut to a size of 30 mm x 30 mm and then bonded to a glass substrate on the zero retardation film side through a (meth)acrylic adhesive to obtain a measurement sample. The layer structure of the measurement sample is glass substrate/(meth)acrylic adhesive layer/zero retardation film/cured material layer/polarizer/cured material layer/TAC film. An alkali-free glass substrate (trade name “Eagle XG” manufactured by Corning) was used as the glass substrate.

Regarding the obtained measurement sample, the MD transmittance and TD transmittance in the wavelength range of 380 to 780 nm were measured using a spectrophotometer equipped with an integrating sphere (product name "V7100" manufactured by Nippon Bunko Co., Ltd.), and the polarization degree at each wavelength was measured. was calculated. Regarding the calculated polarization degree, visibility correction was performed using a 2-degree field of view (C _light source) according to JIS Z 8701:1999 "Color _display method - _XYZ colorimetric system and (Py) was saved.

Additionally, the measurement sample was set in a spectrophotometer with an integrating sphere, with the TAC film side of the polarizing plate as the detector side, and light entering from the glass substrate side.

The degree of polarization is expressed by the following formula:

Polarization degree (λ)=100×(Tp(λ)-Tc(λ))/(Tp(λ)+Tc(λ))

It is defined as

Tp(λ) is the transmittance (%) of the measurement sample measured based on the relationship between linearly polarized light of incident wavelength λ (nm) and parallel Nicols.

Tc(λ) is the transmittance (%) of the measurement sample measured based on the relationship between linearly polarized light of incident wavelength λ (nm) and orthogonal Nicols.

Next, this measurement sample was placed in a high temperature and high humidity environment at a temperature of 85°C and a relative humidity of 85% RH for 500 hours, and then subjected to a durability test in an environment of a temperature of 23°C and a relative humidity of 50% RH for 24 hours. After the durability test, the visibility corrected polarization degree (Py) was obtained by the same method as before the durability test.

The absolute value (|ΔPy|) of the difference between the visibility corrected polarization degree (Py) after the durability test and the visibility corrected polarization degree (Py) before the durability test was calculated to evaluate the optical durability of the polarizing plate. The calculated value of |ΔPy| is shown in Table 1.

The smaller |ΔPy|, the better the optical durability. In all examples and comparative examples, the difference between the visibility corrected polarization degree (Py) after the durability test and the visibility corrected polarization degree (Py) before the durability test showed a negative value.

The details of each component shown in Table 1 are as follows.

a1: Brand name "Epocross WS-300" manufactured by Nippon Shokubai Co., Ltd. [aqueous solution of an oxazoline group-containing acrylic polymer having a 2-oxazoline group as a side chain, solid concentration: 10% by mass, oxazoline value (theoretical value): 130 g solid/eq., oxazoline group weight (theoretical value): 7.7 mmol/g, solid, number average molecular weight: 4×10 ⁴ , weight average molecular weight: 12×10 ⁴ )]

b1:citric acid

b2: tartaric acid

b3: malic acid

b4: butane-1,2,3,4-tetracarboxylic acid

b5: Brand name “AP-10” manufactured by Nippon Sakubi Poval Co., Ltd. [carboxyl group-modified polyvinyl alcohol, average degree of polymerization: 1000, degree of saponification: 88 to 90 mol%]

c1: sulfuric acid

c2: p-toluenesulfonic acid

c3: acetic acid

x1: Product name “Gosepaima Z-200” manufactured by Nippon Kosei Chemical Co., Ltd. [acetoacetyl group-modified polyvinyl alcohol, average degree of polymerization: 1100, degree of saponification: 98.5 mol% or more]

y1: glyoxal

10: 1st thermoplastic resin film, 15: 1st cured material layer, 20: 2nd thermoplastic resin film, 25: 2nd cured material layer, 30: polarizer, 40: adhesive layer, 50: liquid crystal cell.

Claims (13)

A polarizing plate comprising a polarizer, a first cured material layer, and a first thermoplastic resin film in this order,
The first cured layer is,
Oxazoline group-containing polymer (A) and
Compound (B) having a carboxyl group and
A compound (C) that promotes the reaction between the oxazoline group of the oxazoline group-containing polymer (A) and the carboxyl group of the compound (B)
It is a cured layer of a curable composition containing,
The first cured material layer is an adhesive layer for adhering the polarizer and the first thermoplastic resin film, a polarizing plate. The polarizing plate according to claim 1, wherein the content of compound (B) in the curable composition is 0.01 parts by mass or more and 15 parts by mass or less based on 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and compound (B). The method according to claim 1 or 2, wherein the content of compound (C) in the curable composition is more than 10 parts by mass and 100 parts by mass based on 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and compound (B). Polarizer below. The polarizing plate according to claim 1 or 2, wherein compound (B) has two or more carboxyl groups in the molecule. The polarizing plate according to claim 1 or 2, wherein compound (B) has a molecular weight of 1000 or less. delete The method according to claim 1 or 2, wherein the first thermoplastic resin film comprises at least one thermoplastic resin selected from the group consisting of cellulose ester resin, polyester resin, (meth)acrylic resin, and cyclic polyolefin resin. Polarizer. The polarizing plate according to claim 1 or 2, comprising the second thermoplastic resin film, the second cured material layer, the polarizer, the first cured material layer, and the first thermoplastic resin film in this order. The polarizing plate according to claim 1 or 2, wherein the polarizer includes a polyvinyl alcohol-based resin. A curable composition for adhering a polarizer and a first thermoplastic resin film,
Oxazoline group-containing polymer (A) and
Compound (B) having a carboxyl group and
A compound (C) that promotes the reaction between the oxazoline group of the oxazoline group-containing polymer (A) and the carboxyl group of the compound (B)
A curable composition comprising a. The curable composition according to claim 10, wherein the content of compound (B) is 0.01 part by mass or more and 15 parts by mass or less based on 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and compound (B). The curable composition according to claim 10 or 11, wherein the content of compound (C) is more than 10 parts by mass and less than or equal to 100 parts by mass based on 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and compound (B). Oxazoline group-containing polymer (A) and
Compound (B) having a carboxyl group and
A compound (C) that promotes the reaction between the oxazoline group of the oxazoline group-containing polymer (A) and the carboxyl group of the compound (B)
A cured layer formed by curing a curable composition containing,
The content of compound (C) is more than 10 parts by mass and less than or equal to 100 parts by mass based on 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and compound (B),
Compound (B) is a cured material layer with a molecular weight of 1000 or less.