JP6923395B2 - Polarizer - Google Patents

Description

The present invention relates to a polarizing plate.

In recent years, liquid crystal display devices have been developed for mobile device applications such as smartphones and tablet terminals and for in-vehicle devices such as car navigation systems. In such an application, since there is a possibility of being exposed to a harsher environment as compared with the conventional indoor TV application, improvement of the durability of the device is an issue.
Similarly, the optical film constituting the liquid crystal display device or the like is also required to have durability. That is, the optical film incorporated in the liquid crystal display device or the like may be placed in a high temperature or high temperature and high humidity environment, or may be placed in an environment in which high temperature and low temperature are repeated. However, it is required that the optical characteristics do not deteriorate.
An example of the above optical film is a polarizing plate formed by laminating and laminating a thermoplastic resin film such as a protective film on one side or both sides of a polarizing element using an adhesive [for example, JP-A-2009-008860. (Patent Document 1)].

Japanese Unexamined Patent Publication No. 2009-008860

An object of the present invention is to provide a polarizing plate having good optical durability even in a high temperature and high humidity environment.

The present invention provides the following polarizing plates, curable compositions and cured product layers.
[1] A polarizing plate containing a polarizer and a first cured product layer in this order.
The first cured product layer is
Oxazoline group-containing polymer (A) and
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 the compound (B), and
A polarizing plate, which is a cured product layer of a curable composition containing.
[2] The content of the compound (B) in the curable composition is 0.01 parts by mass or more and 15 parts by mass or less in 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and the compound (B). The polarizing plate according to [1].
[3] The content of the compound (C) in the curable composition is more than 10 parts by mass and 100 parts by mass or less with respect to 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and the compound (B). The polarizing plate according to [1] or [2].
[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], which comprises the polarizer, the first cured product layer, and the first thermoplastic resin film in this order.
[7] The first thermoplastic resin film contains one or more thermoplastic resins selected from the group consisting of cellulose ester-based resins, polyester-based resins, (meth) acrylic-based resins, and cyclic polyolefin-based resins [6]. The polarizing plate according to.
[8] The second thermoplastic resin film, the second cured product layer, the polarizer, the first cured product layer, and the first thermoplastic resin film are contained in this order, [6] or [7]. ] The polarizing plate according to.
[9] The polarizing plate according to any one of [1] to [8], wherein the polarizing element 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
The 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), and
A curable composition comprising.
[11] The content of the compound (B) is 0.01 parts by mass or more and 15 parts by mass or less in 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and the compound (B). The curable composition according to description.
[12] The content of the compound (C) is more than 10 parts by mass and 100 parts by mass or less with respect to 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and the compound (B), [10] or The curable composition according to [11].
[13] With the oxazoline group-containing polymer (A),
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 the compound (B), and
A cured product layer obtained by curing a curable composition containing
A cured product layer in which the content of the compound (C) is more than 10 parts by mass and 100 parts by mass or less with respect to 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and the compound (B).

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

It is a schematic cross-sectional view which shows an example of the layer structure of the polarizing plate which concerns on this invention. It is schematic cross-sectional view which shows another example of the layer structure of the polarizing plate which concerns on this invention. It is schematic cross-sectional view which shows another example of the layer structure of the polarizing plate which concerns on this invention. It is schematic cross-sectional view which shows another example of the layer structure of the polarizing plate which concerns on this invention. It is schematic cross-sectional view which shows another example of the layer structure of the polarizing plate which concerns on this invention. It is a schematic cross-sectional view which shows an example of the optical laminate containing the polarizing plate which concerns on this invention.

<Polarizer>
The polarizing plate according to the present invention contains a polarizer and a first cured product layer in this order. The first cured product layer is an oxazoline group-containing polymer (A), a compound having a carboxyl group (B) [hereinafter, also referred to as “compound (B)”. ], And the 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) [hereinafter, also referred to as “compound (C)”. ] Is a cured product layer of the curable composition containing.

The polarizing plate according to the present invention can exhibit good optical durability even in a high temperature and high humidity environment. Good optical durability refers to a property in which the optical characteristics (for example, the degree of polarization) of a polarizing plate are unlikely to deteriorate even when placed in a high-temperature and high-humidity environment.

[1] Structure of polarizing plate Examples of the layer structure of the polarizing plate according to the present invention are shown in FIGS. 1 to 4.
The polarizing plate shown in FIG. 1 includes a polarizing element 30 and a first cured product layer 15 laminated on one surface thereof. The first cured product layer 15 can function as an overcoat layer that coats and protects the surface of the polarizer 30.
It is preferable that the polarizer 30 and the first cured product layer 15 are in direct contact with each other.

The polarizing plate shown in FIG. 2 includes a polarizing element 30 and a first thermoplastic resin film 10 laminated and bonded to one surface thereof via a first cured product layer 15. The first cured product layer 15 can function as an adhesive layer for adhering the polarizer 30 and the first thermoplastic resin film 10.
It is preferable that the first cured product 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 product layer 15 are in direct contact with each other.

The polarizing plate shown in FIG. 3 is formed on the polarizing element 30, the first thermoplastic resin film 10 laminated and bonded to one surface of the polarizing element 30 via the first cured product layer 15, and the other surface of the polarizing element 30. It includes a second thermoplastic resin film 20 that is laminated and bonded via a second cured product layer 25. That is, the polarizing plate according to the present invention includes the second thermoplastic resin film 20, the second cured product layer 25, the polarizer 30, the first cured product layer 15, and the first thermoplastic resin film 10 in this order. There may be. The first cured product layer 15 and the second cured product layer 25 each adhere an adhesive layer for adhering the polarizer 30 and the first thermoplastic resin film 10, and an adhesive layer for adhering the polarizer 30 and the second thermoplastic resin film 20, respectively. It can function as an adhesive layer.
It is preferable that the first cured product 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 product layer 15 are in direct contact with each other.
It is preferable that the second cured product 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 product layer 25 are in direct contact with each other.

The polarizing plate shown in FIG. 4 is laminated and bonded to the polarizer 30, the first cured product layer 15 laminated on one surface thereof, and the other surface of the polarizer 30 via the second cured product layer 25. The second thermoplastic resin film 20 to be formed is included. The first cured product layer 15 can function as an overcoat layer that coats and protects the surface of the polarizer 30. The second cured product layer 25 can function as an adhesive layer for adhering the polarizer 30 and the second thermoplastic resin film 20.
It is preferable that the polarizer 30 and the first cured product layer 15 are in direct contact with each other.
It is preferable that the second cured product 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 product layer 25 are in direct contact with each other.

The polarizing plate shown in FIG. 5 includes a polarizer 30, a first cured product layer 15 laminated on one surface thereof, and a second cured product layer 25 laminated on the other surface of the polarizer 30. .. The first cured product layer 15 and the second cured product layer 25 can function as an overcoat layer that coats and protects the surface of the polarizer 30.
It is preferable that the polarizer 30 and the first cured product layer 15 are in direct contact with each other.
It is preferable that the polarizer 30 and the second cured product layer 25 are in direct contact with each other.

The polarizing plate according to the present invention may include a layer (or film) other than the above. Examples of the other layer include an adhesive laminated on the outer surface of the first thermoplastic resin film 10, the second thermoplastic resin film 20, the first cured product layer 15, the second cured product layer 25, and / or the polarizer 30. Agent layer; Separate film laminated on the outer surface of the pressure-sensitive adhesive layer (also referred to as "release film"); 1st thermoplastic resin film 10, 2nd thermoplastic resin film 20, 1st cured product layer 15, 2nd A protective film (also referred to as a "surface protective film") laminated on the outer surface of the cured product layer 25 and / or the polarizer 30; the first thermoplastic resin film 10, the second thermoplastic resin film 20, and the first cured product layer. 15. Examples thereof include an optically functional film (or layer) laminated on the outer surface of the second cured product layer 25 and / or the polarizer 30 via an adhesive layer or an adhesive layer.

[2] First Cured Product Layer The first cured product layer 15 is a cured product layer of a curable composition (S) containing an oxazoline group-containing polymer (A), compound (B) and 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, and may consist of, for example, one or more skeletons selected from a (meth) acrylic skeleton, a styrene skeleton, an olefin skeleton, an ester skeleton, a carbonate skeleton, and the like. can.
As used herein, the term "(meth) acrylic" refers to at least one selected from the group consisting of acrylics and methacryl. The same applies to the notations such as "(meth) acryloyl" and "(meth) acrylate".

The oxazoline group-containing polymer (A) can have an oxazoline group in the side chain of the skeletal structure.
A preferable example of the oxazoline group-containing polymer (A) is a structural unit (derived from an oxazoline group-containing monomer) having a skeleton structure composed of a (meth) acrylic skeleton as the main component of the structural unit and having an oxazoline group in the side chain as a copolymerization component. It is an oxazoline group-containing (meth) acrylic polymer into which (a constituent unit of the above) has been introduced.
The oxazoline group-containing polymer (A) may be a copolymer of an oxazoline group-containing monomer or a polymer containing an oxazoline group by modifying the side chain functional group of the polymer.

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

The weight average molecular weight of the oxazoline group-containing polymer (A) is preferably 5,000 or more, and more preferably 10,000 or more. The fact that the weight average molecular weight is within the above range means that the optical durability of the polarizing plate is improved, the adhesion between the polarizing element 30 and the first cured product layer 15 and the polarization element 30 and the first thermoplastic resin film 10 are improved. It can be advantageous from the viewpoint of improving the adhesiveness between the two. 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-equivalent value by gel permeation chromatography (GPC).

The amount of oxazoline groups (the 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 groups is smaller than the above range, the optical durability of the polarizing plate may decrease. From this point of view, the amount of oxazoline groups in the oxazoline group-containing polymer is more preferably 3 mmol / g · solid or more, still more preferably 5 mmol / g · solid or more and 9 mmol / g · solid or less. The upper limit of the amount of oxazoline groups is not particularly limited, but is usually 50 mmol / g · solid or less.

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

As the oxazoline group-containing polymer (A), a commercially available product may be used. Specifically, oxazoline group-containing acrylic polymers such as Epocross WS-300, Epocross WS-500, and Epocross WS-700 (all trade names) manufactured by Nippon Shokubai Co., Ltd .; Epocross K-1000 series and Epocross manufactured by Nippon Shokubai Co., Ltd. Examples thereof include oxazoline group-containing acrylic / styrene polymers such as K-2000 series and Epocross RPS series (both are trade names).
The oxazoline group-containing polymer (A) can be used in combination of two or more.
Optical durability and optical properties of the polarizing plate, adhesion between the polymer 30 and the first cured product layer 15, adhesion between the polymer 30 and the first thermoplastic resin film 10, and first curing. From the viewpoint of water resistance of the material layer 15, the oxazoline group-containing polymer (A) is preferably an oxazoline group-containing acrylic polymer such as Epocross WS-300, Epocross WS-500, and Epocross 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, when the solid content concentration of the curable composition (S) is 100% by mass. It is 90% 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 means the optical durability of the polarizing plate, the adhesion between the polarizer 30 and the first cured product layer 15, and the polarizer 30. It is preferable from the viewpoint of adhesion between the first thermoplastic resin film 10 and the first thermoplastic resin film 10.
The solid content concentration means the total concentration of the 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 capable of reacting with the oxazoline group of the oxazoline group-containing polymer (A). The carboxyl group referred to here also includes a derivative of the carboxyl group.
Derivatives of the carboxyl group include a carboxylate anion group. Examples of the cation as the counter ion of the carboxylate anion group include metal ions such as lithium ion, sodium ion and potassium ion; and organic cations such as ammonium ion, sulfonium ion and phosphonium ion.
The curable composition (S) may contain one kind of compound (B) or may contain two or more kinds of compounds (B).

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

An example of a polyfunctional carboxylic acid compound is a dicarboxylic acid compound. Examples of dicarboxylic acid compounds include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimeric acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, tartaric acid, glutamic acid, malic acid, and malein. 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 Examples thereof include acid, 2,5-pyridinedicarboxylic acid, 3,5-pyridinedicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenylmethanedicarboxylic acid, oxaloacetate, methylfumaric acid, 2,6-pyridinedicarboxylic acid and the like.

Another example of a polyfunctional carboxylic acid compound is a tricarboxylic acid compound. Examples of the tricarboxylic acid compound include citric acid, aconitic acid, propane-1,2,3-tricarboxylic acid, trimellitic acid, trimesic acid, hemimeric acid, biphenyl-3,4', 5-tricarboxylic acid, 1,3. Examples thereof include 5-cyclohexanetricarboxylic acid.

Yet another example of a polyfunctional carboxylic acid compound is a tetracarboxylic acid compound. Examples of the tetracarboxylic acid compound include pyromellitic acid, diphenylsulfonetetracarboxylic acid, biphenyltetracarboxylic acid, benzophenone tetracarboxylic acid, naphthalenetetracarboxylic acid, thiophenetetracarboxylic acid, butanetetracarboxylic acid, 1,2,4,5- Examples thereof include tetrakis (4-carboxyphenyl) benzene.

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 contained in the compound (B) 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 the 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 a side chain.
Derivatives of the carboxyl group include a carboxylate anion group. Examples of cations that are counterions of carboxylate anion groups are as described above. An example of a preferred cation is a sodium ion.

The polyvinyl alcohol-based polymer constituting the main chain of the carboxyl group-modified polyvinyl alcohol-based polymer is a vinyl alcohol homopolymer (completely saponified polyvinyl alcohol) obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate. Alternatively, it may be partially saponified polyvinyl alcohol), or a polyvinyl alcohol-based copolymer obtained by saponifying a copolymer of vinyl acetate and another monomer copolymerizable therewith. May be good.
Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.

The degree of saponification of the carboxyl group-modified polyvinyl alcohol-based polymer is usually 80 mol% or more and 100 mol% or less, 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 (modification amount) of the carboxyl group-modified polyvinyl alcohol-based polymer by the carboxyl group (or a derivative thereof) is usually 0.1 mol% or more. The degree of modification of the carboxyl group-modified polyvinyl alcohol-based polymer is the optical durability of the polarizing plate, the adhesion between the polarizing element 30 and the first cured product layer 15, and the degree of modification between the polarizing element 30 and the first thermoplastic resin film 10. From the viewpoint of enhancing the adhesiveness between the layers and the water resistance of the first cured product 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 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 a molecular weight calculated from the chemical structural formula, but when the compound (B) is a polymer, it is a number average molecular weight measured as a standard polystyrene conversion value by gel permeation chromatography (GPC). You may.
The use of compound (B) having a molecular weight of 1000 or less can be advantageous in increasing the optical durability of the polarizing plate. From the viewpoint of the optical durability of the polarizing plate, the molecular weight of the compound (B) is preferably 800 or less, more preferably 500 or less.
The molecular weight of the compound (B) is the optical durability of the polarizing plate, the adhesion between the polarizing element 30 and the first cured product layer 15, and the molecular weight between the polarizing element 30 and the first thermoplastic resin film 10. From the viewpoint of adhesiveness and water resistance of the first cured product 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 the compound (B) in the curable composition (S) is preferably 100 parts by mass based on the total amount of the oxazoline group-containing polymer (A) and the compound (B) from the viewpoint of enhancing the optical durability of the polarizing plate. Is 0.01 parts by mass or more and 15 parts by mass or less, more preferably 0.1 parts by mass or more and 12 parts by mass or less, and further preferably 0.3 parts by mass or more and less than 10 parts by mass.
If the content of the compound (B) is excessively small, it is difficult to obtain good optical durability of the polarizing plate. Further, when the content of the compound (B) is excessively large, the optical durability of the polarizing plate, the adhesion between the polarizing element 30 and the first cured product layer 15, and the polarizing element 30 and the first thermoplastic resin film 10 At least one of the adhesiveness between the first cured product layer 15 and the water resistance of the first cured product layer 15 tends to decrease.

[2-3] Compound (C)
The 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 the compound (B). The promotion referred to here includes the case of initiating the reaction.

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

Examples of the acid compound include inorganic acids such as sulfuric acid, hydrogen chloride, nitrate, phosphoric acid, phosphite, and boric acid; p-toluenesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, methanesulfonic acid, and benzenesulfonic acid. Examples thereof include organic acids such as phenylphosphoric acid, sulfanic acid, phenylphosphonic acid, acetic acid and propionic acid.
The curable composition (S) may contain one kind of compound (C) or may contain two or more kinds of compounds (C).
The compound (C) may be blended in the curable composition (S) as a solution (for example, an aqueous solution) containing the compound (C).

Among them, the compound (C) has the optical durability of the polarizing plate, the adhesion between the polarizer 30 and the first cured product layer 15, and the adhesion between the polarizer 30 and the first thermoplastic resin film 10. From the viewpoint of enhancing the properties, a relatively strong acid is preferable, and examples of such an acid compound include sulfuric acid, hydrogen chloride (hydrochloric acid), nitric acid, p-toluenesulfonic acid and the like.
When the above-mentioned strong acid is used as the compound (C), the adhesion between the polarizer 30 and the first cured product layer 15 and the adhesiveness between the polarizer 30 and the first thermoplastic resin film 10 are particularly high. Tends to improve.

The content of the 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 the compound (B). From the viewpoint of enhancing the optical durability of the polarizing plate, the adhesion between the polarizer 30 and the first cured product layer 15, and the adhesiveness between the polarizer 30 and the first thermoplastic resin film 10. It is preferably 10 parts by mass or more and 100 parts by mass or less, more preferably more than 10 parts by mass and 100 parts by mass or less, and further preferably 15 parts by mass or more and 100 parts by mass or less.
In one preferred embodiment, the content of compound (C) is 80 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. It is less than a part by mass.

If the content of the compound (C) is excessively small, it is difficult to obtain good optical durability of the polarizing plate. Further, when the content of the compound (C) is excessively small, the adhesion between the polarizer 30 and the first cured product layer 15 and the adhesiveness between the polarizer 30 and the first thermoplastic resin film 10 are increased. Tends to decrease.
When the content of the compound (C) is excessively large, the optical durability of the polarizing plate, the adhesion between the polarizing element 30 and the first cured product layer 15, and the polarizing element 30 and the first thermoplastic resin film 10 At least one of the adhesiveness between them and the water resistance of the first cured product layer 15 tends to decrease.

[2-4] Other Components The curable composition (S) can contain other components other than the oxazoline group-containing polymer (A), the compound (B) and the compound (C).
Other components include curable components such as polyvalent aldehydes, melamine compounds, zirconia compounds, zinc compounds, aziridine compounds, glioxal, glioxal derivatives, water-soluble epoxy resins, and cross-linking agents; other than carboxyl group-modified polyvinyl alcohol-based polymers. Modified polyvinyl alcohol-based polymers; Examples thereof include additives such as coupling agents, tackifiers, antioxidants, ultraviolet absorbers, heat stabilizers, and hydrolysis inhibitors.
The curable composition (S) may contain one or more other components.

The curable composition (S) preferably contains a solvent. Examples of the solvent include water, organic solvents, and mixtures thereof. The solvent preferably contains water, but water and a water-soluble organic solvent may be used in combination. Examples of the organic solvent include alcohol solvents such as ethanol and 1-methoxy-2-propanol.
The main component of the solvent is preferably water. The main component means that it occupies 50% by mass or more of the total solvent.
The solid content concentration of the curable composition (S) is usually 0.5% by mass or more and 20% by mass or less, preferably 1% by mass or more and 15% by 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 compounding component is dissolved in a solvent containing water, or a dispersion (for example, an emulsion) in which the compounding component is dispersed in a solvent containing water. .. Further, even when the curable composition (S) is used to form an overcoat layer, the curable composition (S) is a solution in which the compounding components are dissolved in a solvent containing water. It is preferably a dispersion (for example, an emulsion) in which the compounding components are dispersed in a solvent containing water.

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 2 mPa · sec or more and 20 mPa · sec or less. Is even more preferable. If the viscosity at 25 ° C. exceeds 50 mPa · sec, it becomes difficult to apply the coating uniformly, which may cause uneven coating, and may cause problems such as clogging of piping.
The viscosity of the curable composition (S) at 25 ° C. can be measured by an E-type viscometer.

[3] Polarizer The polarizing element 30 is a film having a function of selectively transmitting linearly polarized light in a certain direction from natural light.
As the polarizer 30, a polarizer containing a polyvinyl alcohol-based resin can be mentioned, and more specifically, a polarizer made of a polyvinyl alcohol-based resin film can be mentioned.
Examples of the polarizer composed of the polyvinyl alcohol-based resin film include an iodine-based polarizer in which iodine as a dichroic dye is adsorbed and oriented on the polyvinyl alcohol-based resin film, and a dichroic dye on the polyvinyl alcohol-based resin film. This includes a dye-based polarizer in which a dichroic dye is adsorbed and oriented.
Further, the polarizing element 30 may be a coating type polarizing element in which a dichroic dye in a Riotrovic liquid crystal state is coated on a base film and oriented / immobilized.
The above-mentioned 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 the other direction.

The polarizer 30 is not limited to the absorption type polarizer, but is a reflection type polarizer that selectively transmits linearly polarized light in one direction from natural light and reflects the linearly polarized light in the other direction, or linearly polarized light in the other direction. A scattering type polarizer may be used, but an absorption type polarizer is preferable from the viewpoint of excellent visibility. Of these, a polyvinyl alcohol-based polarizer composed of a polyvinyl alcohol-based resin film is more preferable, and a polyvinyl alcohol-based polarizer in which a dichromatic dye such as iodine or a bicolor dye is adsorbed and oriented on the polyvinyl alcohol-based resin film is used. More preferably, 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, a saponified polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and a copolymer of vinyl acetate and another monomer copolymerizable with the vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.

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

A film formed of such a polyvinyl alcohol-based resin is used as a raw film for a polarizer 30 made of a polyvinyl alcohol-based resin film. The method for forming a film of the polyvinyl alcohol-based resin is not particularly limited, and a known method is adopted. The thickness of the polyvinyl alcohol-based raw film is, for example, 150 μm or less, preferably 100 μm or less (for example, 50 μm or less), and 5 μm or more.

The polarizer 30 composed of the polyvinyl alcohol-based resin film is a step of uniaxially stretching the polyvinyl alcohol-based resin film; a step of adsorbing the bicolor dye by dyeing the polyvinyl alcohol-based resin film with the bicolor dye; It can be produced by a method including a step of treating (cross-linking) a polyvinyl alcohol-based resin film on which a color dye is adsorbed with an aqueous boric acid solution; and a step of washing with water after the treatment with the aqueous boric acid solution.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before dyeing the dichroic dye, at the same time as dyeing, or after dyeing. If the uniaxial stretching is performed after staining, the uniaxial stretching may be performed before the boric acid treatment or during the boric acid treatment. Moreover, uniaxial stretching may be performed in these a plurality of steps.

In uniaxial stretching, rolls having different peripheral speeds may be uniaxially stretched, or thermal rolls may be used to uniaxially stretch the rolls. The uniaxial stretching may be a dry stretching in which the film is stretched in the atmosphere, or a wet stretching in which the polyvinyl alcohol-based resin film is swollen with a solvent such as water. The draw ratio is usually 3 times or more and 8 times or less.

Examples of the method of dyeing a polyvinyl alcohol-based resin film with a dichroic dye include a method of immersing the film in an aqueous solution containing a dichroic dye. As the dichroic dye, iodine or a dichroic organic dye is used. The polyvinyl alcohol-based resin film is preferably immersed in water before the dyeing treatment.

Examples of the method for dyeing with 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 can 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 can be 0.5 parts by mass or more and 20 parts by mass or less per 100 parts by mass of water. Further, the temperature of this aqueous solution can be 20 ° C. or higher and 40 ° C. or lower.
On the other hand, as a dyeing treatment method with a dichroic organic dye, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing a dichroic organic dye and the like can be mentioned. 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 ^{can 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 can 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 a boric acid-containing aqueous solution. When iodine is used as the dichroic pigment, the boric acid-containing aqueous solution preferably contains potassium iodide. The amount of boric acid in the boric acid-containing aqueous solution can 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 can 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 can be 50 ° C. or higher, for example 50 ° C. or higher and 85 ° C. or lower.

The polyvinyl alcohol-based resin film after the boric acid treatment is usually washed with water. The water washing treatment can be performed, for example, by immersing the boric acid-treated polyvinyl alcohol-based resin film in water. The temperature of water in the washing treatment is usually 5 ° C. or higher and 40 ° C. or lower. After washing with water, a drying treatment is performed to obtain a polarizer 30.
The drying process can be performed using a hot air dryer or a far-infrared heater. A polarizing plate can be obtained by forming a cured product layer of the curable composition (S) on the surface of the polarizing element 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 product layer, and the like.

Further, as another example of the method for producing the polarizer 30, for example, the methods described in JP-A-2000-338329 and JP-A-2012-159778 can be mentioned. In this method, a solution containing a polyvinyl alcohol-based resin is applied to the surface of the base film to provide a resin layer, and then a laminated film composed of the base film and the resin layer is stretched, followed by dyeing treatment, cross-linking treatment, and the like. To form a polarizer layer (polarizer 30) from the resin layer. After the first thermoplastic resin film 10 as a protective film or the like is bonded to the polarizer layer surface of this polarizing laminated film composed of the substrate film and the polarizer layer via the curable composition (S), the substrate is used. The film can be peeled off to obtain a polarizing plate having the configuration shown in FIG. When the second thermoplastic resin film 20 is further attached to the surface of the polarizer layer exposed by the peeling of the base film via the curable composition, the polarizing plate having the configuration shown in FIG. 3 is obtained.

The thickness of the polarizer 30 can be 40 μm or less, preferably 30 μm or less (for example, 20 μm or less, further 15 μm or less, and further 10 μm or less or 8 μm or less). According to the methods described in JP-A-2000-338329 and JP-A-2012-159778, the thin film polarizer 30 can be manufactured more easily, and the thickness of the polarizer 30 can be increased to, for example, 20 μm or less. Is 15 μm or less, and even more easily 10 μm or less or 8 μm 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 translucent (preferably optically transparent) thermoplastic resin, for example, a chain polyolefin resin. Polyethylene-based resins such as (polypropylene-based resins, etc.), cyclic polyolefin-based resins (norbornen-based resins, etc.); Cellulosic ester-based resins such as triacetyl cellulose and diacetyl cellulose; polyester-based resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate. A film made of a resin; a polycarbonate-based resin; a (meth) acrylic-based resin; or a mixture thereof, a copolymer, or the like can be used.

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, respectively. The biaxial stretching may be a simultaneous biaxial stretching that simultaneously stretches in two stretching directions, or may be a sequential biaxial stretching that stretches in a second direction different from this after stretching in the first direction.
The first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 may be a protective film that plays a role of protecting the polarizer 30, or is a protective film that also has an optical function such as a retardation film. You can also do it.
The retardation film is an optical functional film used for the purpose of compensating for the retardation by a liquid crystal cell which is an image display element. For example, an arbitrary retardation value was given by stretching a film made of the thermoplastic resin (uniaxial stretching, biaxial stretching, etc.) or forming a liquid crystal layer or the like on the thermoplastic resin film. It can be a retardation film.

Examples of the chain polyolefin resin include homopolymers of chain olefins such as polyethylene resin and polypropylene resin, and copolymers composed of two or more kinds of chain olefins.

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

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

The polyester-based resin is a resin other than the above-mentioned cellulose ester-based resin having an ester bond, and is generally composed of a polyvalent carboxylic acid or a polycondensate of a derivative thereof and a polyhydric alcohol.
Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethylterephthalate, and polycyclohexanedimethylnaphthalate.
Of these, polyethylene terephthalate is preferably used from the viewpoints of mechanical properties, solvent resistance, scratch resistance, cost and the like. The polyethylene terephthalate refers to a resin in which 80 mol% or more of the repeating unit is composed of ethylene terephthalate, and may contain a constituent unit derived from other copolymerization components.

Examples of other copolymerization components include a dicarboxylic acid component and a diol component.
The dicarboxylic acid components include isophthalic acid, 4,4'-dicarboxydiphenyl, 4,4'-dicarboxybenzophenone, bis (4-carboxyphenyl) ethane, adipic acid, sebacic acid, 5-sodium sulfoisophthalic acid, 1 , 4-Dicarboxycyclohexane and the like.
Examples of the diol component include propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, polytetramethylene glycol and the like.
The dicarboxylic acid component and the diol component may be used in combination of two or more, if necessary.
Further, it is also possible to use hydroxycarboxylic acids such as p-hydroxybenzoic acid, p-hydroxyethoxybenzoic acid and β-hydroxyethoxybenzoic acid in combination with the above dicarboxylic acid component and diol component.
As the other copolymerization component, a small amount of a dicarboxylic acid component and / or a diol component having an amide bond, a urethane bond, an ether bond, a carbonate bond and the like may be used.

The polycarbonate resin is a polyester formed from carbonic acid and glycol or bisphenol. Among them, aromatic polycarbonate having a diphenylalkane in the molecular chain is preferably used from the viewpoint of heat resistance, weather resistance and acid resistance.
Examples of polycarbonate include 2,2-bis (4-hydroxyphenyl) propane (also known as bisphenol A), 2,2-bis (4-hydroxyphenyl) butane, 1,1-bis (4-hydroxyphenyl) cyclohexane, and 1, Examples thereof include polycarbonates derived from bisphenols such as 1-bis (4-hydroxyphenyl) isobutane and 1,1-bis (4-hydroxyphenyl) ethane.

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

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

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

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

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

Examples of copolymerization components other than the above-mentioned acrylate ester include methyl 2- (hydroxymethyl) acrylate, methyl 2- (1-hydroxyethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, and 2-. (Hydroxymethyl) hydroxyalkyl acrylate esters such as n-, i- or t-butyl acrylate;
Unsaturated acids such as methacrylic acid and acrylic acid;
Halogenated styrenes such as chlorostyrene and bromostyrene;
Substituted styrenes such as vinyltoluene 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;
Such as monofunctional monomers.
As the other monofunctional monomer, only one kind may be used alone, or two or more kinds may be used in combination.

A polyfunctional monomer may be used as the other copolymerization component.
Examples of the polyfunctional monomer include ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and nonaethylene glycol di (meth). Ethylene glycol such as acrylate, tetradecaethylene glycol di (meth) acrylate, or the hydroxyl groups at both ends of the oligomer are esterified with (meth) acrylic acid;
Esterification of both terminal hydroxyl groups of propylene glycol or its oligomer with (meth) acrylic acid;
The hydroxyl group of a dihydric alcohol such as neopentyl glycol di (meth) acrylate, hexanediol di (meth) acrylate, butanediol di (meth) acrylate esterified with (meth) acrylic acid;
Bisphenol A, an alkylene oxide adduct of bisphenol A, or the hydroxyl groups at both ends of these halogen substituents esterified with (meth) acrylic acid;
Polyhydric alcohols such as trimethylolpropane and pentaerythritol esterified with (meth) acrylic acid, and those terminal hydroxyl groups to which an epoxy group of glycidyl (meth) acrylate is ring-opened and added;
Succinic acid, adipic acid, terephthalic acid, phthalic acid, dibasic acids such as halogen substituents thereof, or alkylene oxide adducts thereof to which an epoxy group of glycidyl (meth) acrylate is cycloadditionally added;
Aryl (meth) acrylate; aromatic divinyl compounds such as divinylbenzene;
And so on.
Of these, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and neopentyl glycol dimethacrylate are preferably used.

The (meth) acrylic resin may be modified by a reaction between functional groups of the copolymer. Examples of the reaction include a demethanol condensation reaction in a polymer chain of a methyl ester group of methyl (meth) acrylate and a hydroxyl group of methyl 2- (hydroxymethyl) acrylate, and a carboxyl group of (meth) acrylate. Examples thereof include a dehydration condensation reaction in a polymer chain with a hydroxyl group of methyl 2- (hydroxymethyl) acrylate.

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

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

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

The (meth) acrylic resin may contain acrylic rubber particles which are impact improving agents from the viewpoint of film forming property on the film, impact resistance of the film, and the like. Acrylic rubber particles are particles containing an elastic polymer mainly composed of an acrylic acid ester as an essential component, and have a single-layer structure substantially consisting of only this elastic polymer, or one elastic polymer. Examples thereof include a multi-layer structure having layers.

Examples of the elastic polymer include a crosslinked elastic copolymer containing alkyl acrylate as a main component and copolymerizing another copolymerizable vinyl-based monomer and a crosslinkable monomer.
The alkyl acrylate which is the main component of the elastic polymer includes, for example, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethyl hexyl acrylate, etc., which have an alkyl group having 1 or more and 8 or less carbon atoms. However, alkyl acrylate having an alkyl group having 4 or more carbon atoms is preferably used.

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

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

A laminate of a film made of a (meth) acrylic resin containing no rubber particles and a film made of a (meth) acrylic resin containing rubber particles is used as a thermoplastic resin film to be bonded to a polarizer 30. You can also. Further, a (meth) acrylic resin layer is formed on one side or both sides of a phase difference developing layer made of a resin different from the (meth) acrylic resin, and the one in which the phase difference is expressed is bonded to the polarizer 30. It can also be a thermoplastic resin film.

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 are each one or more thermoplastics selected from the group consisting of a cellulose ester resin, a polyester resin, a (meth) acrylic resin, and a cyclic polyolefin resin. A film containing a resin is preferable, and a cellulose ester resin film, a polyester resin film, a (meth) acrylic resin film, or a cyclic polyolefin resin film is more preferable.

The first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 may contain an ultraviolet absorber. When the polarizing plate is applied to an image display device such as a liquid crystal display device, a thermoplastic resin film containing an ultraviolet absorber is placed on the visible side of the image display element (for example, a liquid crystal cell), so that the ultraviolet rays of the image display element are used. Deterioration can be suppressed.
Examples of the ultraviolet absorber include salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, nickel complex salt compounds and the like.

The first 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 terms of thickness, presence / absence of additives, their types, retardation characteristics, and the like.

The first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 has a hard coat layer, an antiglare layer, an antireflection layer, a light diffusing layer, and an antistatic layer on the outer surface (the surface opposite to the polarizer 30). A surface treatment layer (coating layer) such as an antifouling layer, an antifouling layer, and a conductive layer may be provided.

The thickness of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is usually 5 μm or more and 200 μm or less, preferably 10 μm or more and 120 μm or less, more preferably 10 μm or more and 85 μm or less, and further preferably 15 μm or more and 65 μm or less. Is. The thickness of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be 50 μm or less, or 40 μm or less, respectively. 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 the image display device.

On the surface to which the curable composition of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is applied, from the viewpoint of improving adhesion, surfaces such as saponification treatment, plasma treatment, corona treatment, and primer treatment are performed. The modification treatment may be performed, or the surface modification treatment may not be performed from the viewpoint of simplifying the process. 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 carry out a saponification treatment from the viewpoint of improving adhesion. Examples of the saponification treatment include a method of immersing in an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide.

[5] Second Curable Layer The curable composition forming the second cured layer 25 may be the above-mentioned curable composition (S), or may be another curable composition different from the above-mentioned curable composition. There may be. The second cured product layer 25 is preferably a cured product layer of the curable composition (S) from the viewpoint of optical durability of the polarizing plate.
When the first cured product layer 15 and the second cured product layer 25 are formed from the curable composition (S), these curable compositions may have the same composition or different compositions. You may.
Examples of 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. Be done.

Examples of the water-based adhesive include water-based adhesives in which an adhesive component such as a polyvinyl alcohol-based resin or a urethane resin is dissolved or dispersed in water.
Water-based adhesives containing polyvinyl alcohol-based resins have curable components such as polyhydric aldehydes, melamine-based compounds, zirconia compounds, zinc compounds, glyoxal, glyoxal derivatives, water-soluble epoxy resins, and cross-linking agents in order to improve adhesiveness. Can be contained.
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. The polyester-based ionomer type urethane resin is a urethane resin having a polyester skeleton, in which a small amount of an ionic component (hydrophilic component) is introduced.

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

The active energy ray-curable adhesive can be an adhesive containing an epoxy-based compound that is cured by cationic polymerization as a curable component, and preferably, an ultraviolet curable adhesive containing such an epoxy-based compound as a curable component. It is an agent. The epoxy-based compound means a compound having an average of 1 or more, preferably 2 or more epoxy groups in the molecule. Only one type of epoxy compound may be used, or two or more types may be used in combination.

As the epoxy compound, a hydride epoxy compound (having an alicyclic ring) obtained by reacting epichlorohydrin with an alicyclic polyol obtained by hydrogenating the aromatic ring of an aromatic polyol. Polyglycidyl ether of polyol); an aliphatic epoxy compound such as an aliphatic polyhydric alcohol or a polyglycidyl ether of an alkylene oxide adduct thereof; an epoxy compound having one or more epoxy groups bonded to an alicyclic ring in the molecule. Examples thereof include certain alicyclic epoxy compounds.

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

When the active energy ray-curable adhesive contains an epoxy compound that is cured by cationic polymerization as a curable component, it preferably contains a photocationic polymerization initiator. Examples of the photocationic polymerization initiator include aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic sulfonium salts; and iron-allene complexes.
When the active energy ray-curable adhesive contains a radically polymerizable component such as a (meth) acrylic compound, it preferably contains a photoradical polymerization initiator. Examples of the photoradical polymerization initiator include an acetophenone-based initiator, a benzophenone-based initiator, a benzoin ether-based initiator, a thioxanthone-based initiator, xanthone, fluorenone, camphorquinone, benzaldehyde, anthraquinone and the like.

The polarizing plate may include an adhesive layer instead of the second cured product layer 25. That is, the second thermoplastic resin film 20 may be attached to the polarizer 30 via the pressure-sensitive adhesive layer. Regarding the pressure-sensitive adhesive layer, the description of the pressure-sensitive adhesive layer described later is cited.

[6] Manufacture of Polarizing Plate A polarizing plate having the configuration shown in FIG. 2 can be obtained by laminating and adhering a first thermoplastic resin film 10 to one surface of a polarizing element 30 via a first cured product layer 15. The polarizing plate having the configuration shown in FIG. 3 can be obtained by further laminating and adhering the second thermoplastic resin film 20 to the other surface of the polarizer 30 via the second cured product layer 25.
When producing a polarizing plate having both the first thermoplastic resin film 10 and the second thermoplastic resin film 20, these films may be laminated and adhered step by step on one side at a time, or the films on both sides may be laminated at the same time. It may be glued.

As a method of adhering the polarizer 30 and the first thermoplastic resin film 10, the curable composition (S) is applied to either one or both of the polarizing element 30 and the first thermoplastic resin film 10. Examples thereof include a method of coating, laminating the other laminating surface on the laminating surface, and pressing from above and below using a laminating roll or the like for laminating.
For coating the curable composition (S), various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used. Further, even in a method in which the polarizing element 30 and the first thermoplastic resin film 10 are continuously supplied so that the bonding surface of both is on the inside, and the curable composition (S) is cast between them. good.

After the polarizer 30 and the first thermoplastic resin film 10 are bonded together, the laminate containing the polarizer 30, the first cured product layer 15, and the first thermoplastic resin film 10 is heat-treated. Is preferable. The temperature of the heat treatment is, for example, 40 ° C. or higher and 100 ° C. or lower, preferably 50 ° C. or higher and 90 ° C. or lower. The solvent contained in the curable composition layer can be removed by heat treatment. In addition, the heat treatment can allow the curing / crosslinking reaction of the curable composition to proceed.

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

When an active energy ray-curable adhesive is used, the curable composition layer is dried if necessary, and then irradiated with active energy rays to cure the curable composition layer.
The light source used for irradiating the active energy beam may be any light source capable of generating ultraviolet rays, electron beams, X-rays and the like. 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, and the like having an emission distribution having a wavelength of 400 nm or less are preferably used.

As shown in FIG. 1, the polarizing plate having no first thermoplastic resin film on the first cured product layer 15 is obtained by applying the curable composition (S) on the surface of the polarizer 30 and laminating the obtained laminate. The body can be produced by subjecting the body to heat treatment at 80 ° C. for 300 seconds, for example, with a hot air dryer. Further, the polarizing plate shown in FIG. 1 can also be produced by producing a laminate composed of a separate film / curable composition (S) / polarizer 30, peeling off the separate film, and then performing heat treatment. Can be done.

The thickness of the first cured product 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, more preferably 10 nm or more and 5 μm or less, and further preferably. Is 20 nm or more and 1 μm or less. The adhesive layer formed from the above-mentioned known water-based adhesive can also have the same thickness.
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 product layer 15 and the second cured product layer 25 may have the same thickness or may be different in thickness.

[7] Other Components of Polarizing Plate [7-1] Optically Functional Film The polarizing plate can be provided with an optical functional film other than the polarizer 30 for imparting a desired optical function. A preferred example thereof is a retardation film.
As described above, the first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 can also serve as a retardation film, but a retardation film can also be laminated separately from these films. In the latter case, the retardation film is a first thermoplastic resin film 10, a second thermoplastic resin film 20, a first cured product layer 15 and / or a second cured product layer 25 via an adhesive layer or an adhesive layer. Can be laminated on the outer surface of.

The retardation film is a birefringent film composed of a stretched film of a translucent thermoplastic resin; a film in which a discotic liquid crystal or a nematic liquid crystal is oriented and fixed; the above liquid crystal layer is formed on a base film. The ones that have been made are mentioned.
The base film is usually a film made of a thermoplastic resin, and an example of the thermoplastic resin is a cellulose ester resin such as triacetyl cellulose.

Examples of other optical functional films (optical members) that can be included in the polarizing plate are a condenser plate, a brightness improving film, a reflective layer (reflective film), a semi-transmissive reflective layer (semi-transmissive reflective film), and a light diffusing layer (light). Diffuse film) etc. These are generally provided when the polarizing plate is a polarizing plate arranged on the back surface side (backlight side) of the liquid crystal cell.

The condensing plate is used for the purpose of controlling the optical path, and may be a prism array sheet, a lens array sheet, a sheet with dots, or the like.

The 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 polarizing separation sheet designed to generate anisotropy in reflectance by laminating a plurality of thin films having different refractive index anisotropy, an alignment film of cholesteric liquid crystal polymer, and its orientation. Examples thereof include a circularly polarized light separation sheet in which a liquid crystal layer is supported on a base film.

The reflective layer, the semitransmissive reflective layer, and the light diffusing layer are provided to make the polarizing plate a reflective type, a semitransparent type, and a diffusing type optical member, respectively. The reflective polarizing plate is used in a liquid crystal display device of a type that reflects and displays incident light from the viewing side, and since a light source such as a backlight can be omitted, the liquid crystal display device can be easily made thinner. The transflective polarizing plate is used in a liquid crystal display device of a type that displays light from a backlight in a dark place as a reflective type in a bright place. Further, the diffusion type polarizing plate is used in a liquid crystal display device that imparts light diffusivity and suppresses display defects such as moire. The reflective layer, the transflective reflective layer and the light diffusing layer can be formed by a known method.

[7-2] Adhesive Layer The polarizing plate according to the present invention may include an adhesive layer. Examples of the pressure-sensitive adhesive layer include a pressure-sensitive adhesive layer for bonding a polarizing plate to an image display element such as a liquid crystal cell or another optical member. The pressure-sensitive adhesive layer is formed on the outer surface of the polarizer 30 in the polarizing plate having the structure shown in FIGS. 1 and 2, and the first thermoplastic resin film 10 or the second thermoplastic resin film in the polarizing plate having the structure shown in FIG. The outer surface of 20, the outer surface of the first cured product layer 15 or the second thermoplastic resin film 20 in the polarizing plate having the configuration shown in FIG. 4, and the first cured product layer 15 or the polarizing plate having the configuration shown in FIG. It can be laminated on the outer surface of the second cured product layer 25.

As the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer, a (meth) acrylic resin, a silicone-based resin, a polyester-based resin, a polyurethane-based resin, a polyether-based resin, or the like as a base polymer can be used. Among them, a (meth) acrylic pressure-sensitive adhesive is preferable from the viewpoints of transparency, adhesive strength, reliability, weather resistance, heat resistance, reworkability and the like.
The (meth) acrylic pressure-sensitive adhesive includes a (meth) acrylic acid alkyl ester having an alkyl group having 20 or less carbon atoms such as a methyl group, an ethyl group, an n-, i- or t-butyl group, and (meth). A weight average molecular weight of a functional group-containing (meth) acrylic monomer such as acrylic acid or hydroxyethyl (meth) acrylate blended so that the glass transition temperature is preferably 25 ° C. or lower, more preferably 0 ° C. or lower. A (meth) acrylic resin having a value of 100,000 or more is useful as a base polymer.

To form the pressure-sensitive adhesive layer on the polarizing plate, for example, the pressure-sensitive adhesive composition is dissolved or dispersed in an organic solvent such as toluene or ethyl acetate to prepare a pressure-sensitive adhesive liquid, which is directly applied to the target surface of the polarizing plate. The adhesive layer is formed in the form of a sheet on the separate film that has been subjected to the mold release treatment, and the adhesive layer is transferred to the target surface of the polarizing plate. Can be done.
The thickness of the pressure-sensitive adhesive layer is determined according to the adhesive strength and the like, but a range of 1 μm or more and 50 μm or less is appropriate, and preferably 2 μm or more and 40 μm or less.

The polarizing plate may include the above-mentioned separate film. The separate film can be a film made of a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate, or the like. Of these, a polyethylene terephthalate stretched film is preferable.

The pressure-sensitive adhesive layer contains, if necessary, a filler made of glass fiber, glass beads, resin beads, metal powder or other inorganic powder, a pigment, a colorant, an antioxidant, an ultraviolet absorber, an antioxidant and the like. be able to.

[7-3] Protect film The polarizing plate according to the present invention has a surface (typically, a first thermoplastic resin film 10, a second thermoplastic resin film 20, a first cured product layer 15 and / or a second). A protective film for protecting the surface of the cured product layer 25) can be included. After the polarizing plate is attached to, for example, an image display element or another optical member, the protective film is peeled off and removed together with the adhesive layer contained therein.

The protective film is composed of, for example, a base film and an adhesive layer laminated on the base film. The above description is cited for the pressure-sensitive adhesive layer.
The resin constituting the base film is, for example, a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, or a thermoplastic resin such as a polycarbonate resin. be able to. A polyester resin such as polyethylene terephthalate is preferable.

<Liquid crystal panel and liquid crystal display device>
The polarizing plate according to the present invention can be used for a liquid crystal panel and a liquid crystal display device. The liquid crystal panel includes a liquid crystal cell and polarizing plates arranged on both sides thereof. The liquid crystal display device includes a liquid crystal panel and a backlight.
The polarizing plate according to the present invention can be arranged on one side or both sides of the liquid crystal cell. An adhesive layer can be used for attaching the polarizing plate and the liquid crystal cell.
FIG. 6 shows an example of an optical laminate in which a polarizing plate is laminated on a liquid crystal cell via an adhesive layer. The optical laminate shown in FIG. 6 is obtained by laminating the polarizing plate shown in FIG. 3 on one surface of the liquid crystal cell 50 via the adhesive layer 40, and the first thermoplastic resin film 10, the first. The cured product layer 15, the polarizing element 30, the second cured product layer 25, the second thermoplastic resin film 20, the pressure-sensitive adhesive layer 40, and the liquid crystal cell 50 are included in this order. For the pressure-sensitive adhesive layer 40, the above description regarding the pressure-sensitive adhesive layer is cited.
The liquid crystal cell may be any one, and various liquid crystal cells such as an active matrix-driven liquid crystal cell typified by a thin film transistor type and a simple matrix-driven liquid crystal cell typified by a super twisted nematic type are used. The liquid crystal panel and the liquid crystal display device can be formed. The polarizing plates provided on both sides of the liquid crystal cell may be the same or different.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these examples. In the examples,% and parts representing the content or the amount used 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 that promotes the reaction between the oxazoline group of the oxazoline group-containing polymer (A) and the carboxyl group of the compound (B) ( C) is abbreviated as (A), (B), and (C), respectively.

(Manufacturing example: Fabrication of polarizer)
After immersing a 60 μm-thick polyvinyl alcohol film (average degree of polymerization: about 2,400, saponification degree: 99.9 mol% or more) in pure water at 30 ° C., the mass ratio of iodine / potassium iodide / water is increased. It was immersed in an aqueous solution at 30 ° C. of 0.02 / 2/100. Then, it was immersed in an aqueous solution at 56.5 ° C. having a mass ratio of potassium iodide / boric acid / water of 12/5/100. Subsequently, the mixture was washed with pure water at 8 ° C. and then dried at 65 ° C. to obtain a polarizer having a thickness of 23 μm in which iodine was adsorbed and oriented on a polyvinyl alcohol film. The stretching was mainly carried out in the steps of iodine staining 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 A curable composition (adhesive aqueous solution) was prepared by mixing the components shown in Table 1 with pure water as a solvent in the blending amounts shown in Table 1. The unit of the blending amount of each component shown in Table 1 is a mass part, and the blending amount of each component is the amount in terms of solid content. In each Example and Comparative Example, the total concentration of (A) and (B) in the obtained curable composition was 3.0% by mass.

(2) Preparation of Polarizing Plate A triacetyl cellulose (TAC) film [trade name "KC4UAW" manufactured by Konica Minolta Opto Co., Ltd., thickness: 40 μm] is saponified on one side and then saponified on the saponified surface. The curable composition prepared in (1) above is coated with a bar coater, and one side of a zero retardation film [trade name "ZEONOR" manufactured by Nippon Zeon Co., Ltd.] made of a cyclic polyolefin resin having a thickness of 23 μm. Was subjected to corona treatment, and the curable composition prepared in (1) above was coated on the corona-treated surface using a bar coater. A saponified TAC film is laminated on one surface of the polarizer and a zero retardation film is laminated on the other surface so that the curable composition layer is on the polarizer side, so that the zero retardation film / curability A laminate having a layer structure of a composition layer / a polarizer / a curable composition layer / a TAC film was obtained. By heat-treating this laminate at 80 ° C. for 300 seconds with a hot air dryer, a polarizing plate having a layer structure of zero retardation film / cured product layer / polarizer / cured product layer / TAC film can be obtained. Made. The thickness of the cured product layer in the produced polarizing plate was 20 to 60 nm per layer.

(3) Evaluation of Optical Durability After cutting the obtained polarizing plate into a size of 30 mm × 30 mm, it is attached to a glass substrate via a (meth) acrylic adhesive on the zero retardation film side, and a measurement sample is obtained. Got The layer structure of the measurement sample is a glass substrate / (meth) acrylic pressure-sensitive adhesive layer / zero retardation film / cured product layer / polarizer / cured product layer / TAC film. As the glass substrate, a non-alkali glass substrate [trade name "Eagle XG" manufactured by Corning Inc.] was used.
For the obtained measurement sample, MD transmittance and TD transmittance in the wavelength range of 380 to 780 nm were measured using a spectrophotometer with an integrating sphere [product name "V7100" manufactured by JASCO Corporation], and each wavelength was measured. The degree of polarization in was calculated. The calculated degree of polarization was corrected for luminosity factor using the two-degree field of view (C light source) of JIS Z 8701: 1999 "Color display method-XYZ color system and X ₁₀ Y ₁₀ Z _{10 color system" before the durability test.} The luminosity factor correction polarization degree Py was determined. The measurement sample was set in a spectrophotometer with an integrating sphere so that the TAC film side of the polarizing plate was the detector side and the light entered from the glass substrate side.

The degree of polarization is calculated by the following formula:
Polarization degree (λ) = 100 × (Tp (λ) -Tc (λ)) / (Tp (λ) + Tc (λ))
Defined in.
Tp (λ) is the transmittance (%) of the measurement sample measured in relation to the linearly polarized light of the incident wavelength λ (nm) and the parallel Nicol.
Tc (λ) is the transmittance (%) of the measurement sample measured in relation to the linearly polarized light of the incident wavelength λ (nm) and the cross Nicol.

Next, this measurement sample was placed in a high-temperature and high-humidity environment with a temperature of 85 ° C. and a relative humidity of 85% RH for 500 hours, and then subjected to a durability test in which the measurement sample was placed in an environment with a temperature of 23 ° C. and a relative humidity of 50% RH for 24 hours. After the endurance test, the luminous efficiency correction polarization degree Py was determined by the same method as before the endurance test.
The absolute value (| ΔPy |) of the difference between the luminous efficiency corrected polarization degree Py after the durability test and the visual sensitivity correction polarization degree Py before the durability test was calculated, and the optical durability of the polarizing plate was evaluated. The calculated values of | ΔPy | are shown in Table 1.
The smaller | ΔPy |, the better the optical durability. In each of the Examples and Comparative Examples, the difference between the luminous efficiency-corrected polarization degree Py after the endurance test and the luminous efficiency-corrected polarization degree Py before the endurance test showed a negative value.

Details of each component shown in Table 1 are as follows.
a1: Trade name "Epocross WS-300" manufactured by Nippon Catalyst Co., Ltd. [2-Aqueous solution of oxazoline group-containing acrylic polymer having an oxazoline group as a side chain, solid content 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 Japan Vam & Poval Co., Ltd. [Carboxyl group-modified polyvinyl alcohol , Average degree of polymerization: 1000, Degree of citrate: 88-90 mol%]
c1: Sulfuric acid c2: p-toluenesulfonic acid c3: Acetic acid x1: Product name "Gosefimer Z-200" manufactured by Nippon Synthetic Chemical Industry Co., Ltd. [Acetyl 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 product layer, 20 2nd thermoplastic resin film, 25 2nd cured product layer, 30 polarizer, 40 adhesive layer, 50 liquid crystal cell.

Claims (16)

A polarizing plate containing a polarizer, a first cured product layer, and a first thermoplastic resin film in this order.
The first cured product layer is
Oxazoline group-containing polymer (A) and
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 the compound (B), and
Cured layer der curable composition containing is,
The first cured product layer is a polarizing plate which is an adhesive layer for adhering the polarizer and the first thermoplastic resin film. A polarizing plate containing a polarizer and a first cured product layer in this order.
The first cured product layer is
Oxazoline group-containing polymer (A) and
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 the compound (B), and
Is a cured product layer of a curable composition containing
Compound (B) is a polarizing plate which is a dicarboxylic acid compound. The content of the 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 the compound (B). Item 2. The polarizing plate according to Item 1 or 2. Claimed that the content of the compound (C) in the curable composition is more than 10 parts by mass and 100 parts by mass or less with respect to 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and the compound (B). Item 3. The polarizing plate according to any one of Items 1 to 3. The polarizing plate according to claim 1, wherein the compound (B) has two or more carboxyl groups in the molecule. The polarizing plate according to claim 5, wherein the compound (B) is a dicarboxylic acid compound. The polarizing plate according to any one of claims 1 to 6 , wherein the compound (B) has a molecular weight of 1000 or less. The polarizing plate according to claim 2 , further comprising the polarizer, the first cured product layer, and the first thermoplastic resin film in this order. The first thermoplastic resin film comprises one or more thermoplastic resins selected from the group consisting of cellulose ester resins, polyester resins, (meth) acrylic resins and cyclic polyolefin resins, according to claim 1 or 8 . The polarizing plate according to the description. The first, 8 or 9 , wherein the second thermoplastic resin film, the second cured product layer, the polarizer, the first cured product layer, and the first thermoplastic resin film are included in this order. Polarizing plate. The polarizing plate according to any one of claims 1 to 10 , wherein the polarizing element contains 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
The 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), and
A curable composition comprising. The curable composition according to claim 12, wherein the compound (B) is a dicarboxylic acid compound. 12. Curable composition. Any of claims 12 to 14, wherein the content of the compound (C) is more than 10 parts by mass and 100 parts by mass or less with respect to 100 parts by mass of the total amount of the oxazoline group-containing polymer (A) and the compound (B). or curable composition according to item 1. Oxazoline group-containing polymer (A) and
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 the compound (B), and
A cured product layer obtained by curing a curable composition containing
The content of the compound (C) is, relative to the total amount 100 mass parts of oxazoline group-containing polymer (A) and the compound (B), Ri 10 parts by ultra 100 parts by der less,
Compound (B) is a cured product layer which is a dicarboxylic acid compound.

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