JP7308759B2 - Optical laminate and image display device - Google Patents

Description

The present invention relates to curable compositions. The present invention also relates to an optical layered body including a cured product layer composed of a cured product of the curable composition, and an image display device including the optical layered body.

2. Description of the Related Art In recent years, image display devices have been developed for use in mobile equipment such as smartphones and tablet terminals, and in-vehicle equipment such as car navigation systems. In such applications, there is a possibility of exposure to harsh environments compared to conventional indoor TV applications.

Durability is also required for optical members constituting liquid crystal display devices, for example, optical laminates. That is, an optical member incorporated in a liquid crystal display device or the like may be placed in a high temperature, high temperature and high humidity environment, or in an environment where high temperature and low temperature are repeated. Even in these environments, it is required that the optical properties do not deteriorate.

The optical layered body includes an optical layered body including a cured product layer composed of a cured product of a curable composition. An example of such an optical laminate is a polarizer. For example, Japanese Patent Application Laid-Open No. 2009-008860 (Patent Document 1) discloses a polarizing plate in which a transparent protective film is laminated on a polarizer with a cured product layer (adhesive layer) interposed therebetween.

Japanese Patent Application Laid-Open No. 2009-008860

An object of the present invention is to provide an optical laminate having a cured product layer composed of a cured product of a curable composition and having good wet heat durability (durability under high temperature and high humidity environments). The object is to provide a composition.

Another object of the present invention is to provide an optical laminate having good wet heat durability, which includes a cured product layer composed of a cured product of a curable composition, and an image display device including the same.

The present invention provides a curable composition, an optical laminate, an image display device, and an adhesive composition for polarizing plates, which are described below.

[1] A curable composition comprising an oxazoline group-containing polymer (A) and an iodine compound (B).

[2] The curable composition according to [1], further comprising at least one selected from the group consisting of a compound (C) having a carboxyl group and an acid anhydride of the compound (C).

[3] The curable composition according to [2], further comprising a compound (D) that accelerates the reaction between the oxazoline group of the oxazoline group-containing polymer (A) and the carboxyl group of the compound (C) having a carboxyl group. thing.

[4] An optical laminate comprising an optical film and a first cured product layer composed of a cured product of the curable composition according to any one of [1] to [3].

[5] The optical laminate according to [4], comprising the optical film, the first cured material layer, and the first thermoplastic resin film in this order.

[6] The description of [5], comprising a second thermoplastic resin film, a second cured layer, the optical film, the first cured layer, and the first thermoplastic resin film in this order. Optical laminate.

[7] The optical laminate according to any one of [4] to [6], wherein the optical film is a polarizer.

[8] An image display device comprising the optical layered body according to any one of [4] to [7] and an image display element.

[9] An adhesive composition for a polarizing plate, containing an oxazoline group-containing polymer (A) and an iodine compound (B).

It is possible to provide a curable composition that includes a cured product layer composed of a cured product of the curable composition and that can provide an optical laminate having good wet heat durability.

INDUSTRIAL APPLICABILITY It is possible to provide an optical laminate having a cured product layer composed of a cured product of a curable composition and having good wet heat durability, and an image display device including the same.

1 is a schematic cross-sectional view showing an example of an optical layered body according to the present invention; FIG. FIG. 4 is a schematic cross-sectional view showing another example of the layer structure of the optical layered body according to the present invention; FIG. 4 is a schematic cross-sectional view showing another example of the layer structure of the optical layered body according to the present invention; FIG. 4 is a schematic cross-sectional view showing another example of the layer structure of the optical layered body according to the present invention; FIG. 4 is a schematic cross-sectional view showing another example of the layer structure of the optical layered body according to the present invention; FIG. 4 is a schematic cross-sectional view showing another example of the layer structure of the optical layered body according to the present invention;

<Curable composition>
The curable composition according to the present invention contains an oxazoline group-containing polymer (A) and an iodine compound (B).

Hereinafter, the curable composition according to the present invention is also referred to as "curable composition (S)". A cured product layer composed of a cured product of the curable composition (S) is also referred to as a “first cured product layer”.

An optical layered body including the first cured material layer can provide an optical layered body having good wet heat durability.

[1] Oxazoline group-containing polymer (A)
The oxazoline group-containing polymer (A) is a polymer having an oxazoline group in its molecule, preferably a polymer having an oxazoline group in its side chain.

The skeleton structure of the oxazoline group-containing polymer (A) is not particularly limited. can.

As used herein, "(meth)acryl" represents at least one selected from the group consisting of acryl and methacryl. The same applies to notations such as "(meth)acryloyl" and "(meth)acrylate".

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

The oxazoline group-containing polymer (A) may contain a structural unit having an oxazoline group in its side chain (a structural unit derived from an oxazoline group-containing monomer) and a structural unit having no oxazoline group.

A preferred example of the oxazoline group-containing polymer (A) includes a structural unit containing a skeleton structure consisting of a (meth)acrylic skeleton as a main component of the structural unit, and a structural unit having an oxazoline group in a side chain as a copolymerization component (derived from an oxazoline group-containing monomer is an oxazoline group-containing (meth)acrylic polymer into which a structural unit of is introduced.

As the oxazoline group-containing polymer (A), in addition to copolymerization of oxazoline group-containing monomers, polymers containing oxazoline groups by modifying the side chain functional groups of the polymer may be used.

The oxazoline group includes, for example, 2-oxazoline group, 3-oxazoline group, 4-oxazoline group and the like. The oxazoline group is preferably 2-oxazoline group and 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, more preferably 10,000 or more. The fact that the weight average molecular weight is in the above range improves the wet heat durability of the optical layered body, the adhesion between the optical film and the first cured layer in the optical layered body, and the first cured layer and the first thermoplastic layer. It can be advantageous from the viewpoint of adhesion to the resin film.

The weight average molecular weight of the oxazoline group-containing polymer (A) is usually 1,000,000 or less.

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

The oxazoline group content of the oxazoline group-containing polymer (A) (the number of moles of oxazoline groups per 1 g of solid content of the oxazoline group-containing polymer (A)) is preferably 0.4 mmol/g·solid or more. If the amount of oxazoline groups is less than the above range, the wet heat durability of the optical laminate may be disadvantageous. From this point of view, the oxazoline group content of 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.

Although the upper limit of the amount of oxazoline groups is not particularly limited, it is usually 50 mmol/g·solid or less.

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

A commercially available product may be used as the oxazoline group-containing polymer (A). Specifically, oxazoline group-containing acrylic polymers such as Nippon Shokubai Co., Ltd. Epocross WS-300, Epocross WS-500, Epocross WS-700 (all trade names); Nippon Shokubai Co., Ltd. Epocross K-1000 series, Epocross Examples include oxazoline group-containing acrylic/styrene polymers such as K-2000 series and Epocross RPS series (both trade names).

Two or more kinds of the oxazoline group-containing polymer (A) can be used in combination.
Wet heat durability and optical properties of the optical laminate, adhesion between the optical film and the first cured layer in the optical laminate, adhesion between the first cured layer and the first thermoplastic resin film, and From the viewpoint of water resistance of the first cured product layer, 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 5% by mass or more and 95% by mass or less, more preferably 10% by mass or more when the solid content concentration of the curable composition (S) is 100% by mass. It is 90 mass % or less, more preferably 20 mass % or more and 85 mass % or less. Setting the content of the oxazoline group-containing polymer (A) within the above range improves the wet heat durability of the optical laminate, the adhesion between the optical film and the first cured layer in the optical laminate, It is preferable from the viewpoint of adhesion between the first cured material layer and the first thermoplastic resin film.

The solid content concentration refers to the total concentration of components other than the solvent contained in the curable composition (S).
[2] Iodine compound (B)
The iodine compound (B) is a compound containing an iodine element. The curable composition (S) may contain one iodine compound (B), or may contain two or more iodine compounds (B).

Examples of the iodine compound (B) include the following.
a) inorganic iodide salts alkali metal iodides such as lithium iodide, sodium iodide, potassium iodide, rubidium iodide, cesium iodide;
iodides alkaline earth metal salts such as beryllium iodide, magnesium iodide, calcium iodide, barium iodide, strontium iodide;
light or heavy metal salts of iodides such as boron iodide, aluminum iodide, zinc iodide, titanium iodide, copper iodide, vanadium iodide, chromium iodide, manganese iodide, nickel iodide;
ammonium iodide b) other inorganic iodine compounds iodine (I ₂ ), hydrogen iodide, iodic acid, sodium iodate, potassium iodate, calcium iodate, etc. c) organic iodide salts ammonium iodide, tetraethylammonium iodide, Ammonium salts of iodides such as tetrabutylammonium iodide and ammonium iodate;
Phosphonium salts of iodides such as tetrabutylphosphine and tetraphenylphosphine;
trimethylsulfoxonium iodide;
imidazolium iodide salt;
pyridinium iodide salt;
sulfonium iodides d) other organic iodine compounds alkyl iodides such as methyl iodide, ethyl iodide, butyl iodide;
aromatic iodine compounds such as iodonaphthalene, iodobenzene, iodobenzoic acid, iodosalicylic acid, iodophenol;
iodoacetic acid, iodopropionic acid, 2-iodobutyric acid, 2-iodo-2-phenylacetic acid As described later, the curable composition (S) is preferably a water-based composition. When the curable composition (S) is an aqueous composition, the iodine compound (B) is preferably an iodide salt from the viewpoint of solubility or dispersibility in the composition, and an inorganic iodide salt. It is more preferable to have For the same reason, the iodine compound (B) is preferably water-soluble.

The content of the iodine compound (B) in the curable composition (S) is generally 1 part by mass or more with respect to 100 parts by mass of the oxazoline group-containing polymer (A), from the viewpoint of enhancing the wet heat durability of the optical laminate. 300 parts by mass or less, preferably 2 parts by mass or more and 250 parts by mass or less, more preferably 5 parts by mass or more and 200 parts by mass or less, still more preferably 10 parts by mass or more and 180 parts by mass or less, and still further It is preferably 10 parts by mass or more and 150 parts by mass or less.

In one embodiment, the content of the iodine compound (B) is 10 parts by mass or more and 160 parts by mass or less, 10 parts by mass or more and 150 parts by mass or less, with respect to 100 parts by mass of the oxazoline group-containing polymer (A). It is 10 parts by mass or more and 120 parts by mass or less or 10 parts by mass or more and 140 parts by mass or less.

If the content of the iodine compound (B) is excessively small, it is difficult to obtain the effect of increasing the wet heat durability of the optical layered body by containing the iodine compound (B). Also, if the content of the iodine compound (B) is excessively high, the adhesion between the optical film and the first cured layer in the optical laminate, and the adhesion between the first cured layer and the first thermoplastic resin film There is a tendency that at least one of the adhesion between the layers tends to decrease.

[3] Compound (C) having a carboxyl group and acid anhydride of the compound (C) The curable composition (S) is selected from a compound (C) having a carboxyl group and an acid anhydride of the compound (C). can further include at least one of Hereinafter, the compound (C) having a carboxyl group is also referred to as "compound (C)".

The compound (C) is a compound having a carboxyl group capable of reacting with the oxazoline group of the oxazoline group-containing polymer (A). The carboxyl group as used herein includes derivatives of the carboxyl group, but does not include the acid anhydride of the compound (C).

Derivatives of carboxyl groups include carboxylate anion groups. Examples of cations serving as counter ions for carboxylate anion groups include metal ions such as lithium ions, sodium ions and potassium ions; organic cations such as ammonium ions, sulfonium ions and phosphonium ions.

The curable composition (S) may contain one compound (C), or may contain two or more compounds (C). The curable composition (S) may contain one type of acid anhydride of the compound (C), or may contain two or more types of acid anhydrides of the compound (C). The curable composition (S) may contain one or more compounds (C) and one or more acid anhydrides of the compounds (C).

Among them, the compound (C) is useful for wet heat durability of the optical layered body, adhesion between the optical film and the first cured layer in the optical layered body, and between the first cured layer and the first thermoplastic resin film. and a compound having two or more carboxyl groups (or derivatives thereof) in the molecule (polyfunctional carboxylic acid compound) from the viewpoint of enhancing the adhesion of the first cured product layer and the water resistance of the first cured product layer.

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

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

Still another example of polyfunctional carboxylic acid compounds is tetracarboxylic acid compounds. Tetracarboxylic acid compounds include pyromellitic acid, diphenylsulfonetetracarboxylic acid, biphenyltetracarboxylic acid, benzophenonetetracarboxylic acid, naphthalenetetracarboxylic acid, thiophenetetracarboxylic acid, butanetetracarboxylic acid, 1,2,4,5- tetrakis(4-carboxyphenyl)benzene and the like.

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

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

From the viewpoint of wet heat durability of the optical layered body, the number of carboxyl groups possessed by the compound (C) 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. One example of the polymer is a carboxyl group-modified polymer. An example of the carboxyl group-modified polymer is a carboxyl group-modified polyvinyl alcohol polymer.

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

Derivatives of carboxyl groups include carboxylate anion groups. Examples of cations that serve as counter ions for carboxylate anion groups are described above. An example of a preferred cation is the sodium ion.

The polyvinyl alcohol-based polymer that constitutes the main chain of the carboxyl group-modified polyvinyl alcohol-based polymer is a vinyl alcohol homopolymer obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate (fully saponified polyvinyl alcohol or partially saponified polyvinyl alcohol), or a polyvinyl alcohol copolymer obtained by saponifying a copolymer of vinyl acetate and another monomer copolymerizable therewith, good too.

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 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 polymer can be measured according to JIS K 6726:1994.

The degree of modification (modified amount) of the carboxyl group-modified polyvinyl alcohol polymer with the carboxyl group (or derivative thereof) is usually 0.1 mol % or more. The degree of modification of the carboxyl group-modified polyvinyl alcohol polymer is the wet heat durability of the optical laminate, the adhesion between the optical film and the first cured layer in the optical laminate, and the first cured layer and the first thermoplasticity. From the viewpoint of enhancing the adhesion between the resin film and the water resistance of the first cured product layer, it is preferably 0.5 mol% or more and 40 mol% or less, more preferably 1 mol% or more and 20 mol% or less. be. Denaturation can be measured, for example, by ¹ H-NMR.

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

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

In one preferred embodiment, compound (C) 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 (C) is a polymer, it is a number average molecular weight measured as a standard polystyrene conversion value by gel permeation chromatography (GPC). may

Using the compound (C) having a molecular weight of 1000 or less can be advantageous in enhancing the wet heat durability of the optical layered body. From the viewpoint of wet heat durability of the optical layered body, the molecular weight of the compound (C) is preferably 800 or less, more preferably 500 or less.

Further, the molecular weight of the compound (C) determines the wet heat durability of the optical layered body, the adhesion between the optical film and the first cured layer in the optical layered body, and the first cured layer and the first thermoplastic resin film. It is preferably 90 or more, more preferably 100 or more, from the viewpoint of adhesion between.

Preferred examples of compound (C) are citric acid, malic acid, maleic acid and tartaric acid.
Examples of acid anhydrides of compound (C) include carboxylic acid anhydrides. Examples of carboxylic anhydrides include acetic anhydride, propionic anhydride, oxalic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, and benzoic anhydride.

The content of at least one selected from the compound (C) and the acid anhydride of the compound (C) is, from the viewpoint of enhancing the wet heat durability of the optical laminate, relative to 100 parts by mass of the oxazoline group-containing polymer (A) , preferably 0.01 parts by mass or more and 30 parts by mass or less, more preferably 0.1 parts by mass or more and 25 parts by mass or less, still more preferably 0.2 parts by mass or more and 20 parts by mass or less, still further It is preferably from 0.2 parts by mass to 15 parts by mass, and particularly preferably from 0.3 parts by mass to 15 parts by mass.

In one embodiment, the content of at least one selected from the compound (C) and the acid anhydride of the compound (C) is 0.3 parts by mass with respect to 100 parts by mass of the oxazoline group-containing polymer (A) 0.5 to 10 parts by mass, 0.5 to 8 parts by mass, or 1 to 8 parts by mass.

If the content of at least one selected from the compound (C) and the acid anhydride of the compound (C) is excessively small, it is difficult to obtain the effect of enhancing the wet heat durability of the optical layered body. Also, if the content of at least one selected from the compound (C) and the acid anhydride of the compound (C) is excessively high, the effect of increasing the wet heat durability of the optical layered body tends to decrease.

[4] A compound (D) that accelerates the reaction between the oxazoline group of the oxazoline group-containing polymer (A) and the carboxyl group of the compound (C) having a carboxyl group
The curable composition (S) further contains a compound (D) that accelerates the reaction between the oxazoline group of the oxazoline group-containing polymer (A) and the carboxyl group of the compound (C) having a carboxyl group. Hereinafter, this compound is also referred to as "compound (D)". Acceleration here includes the case of initiating the reaction.

When the curable composition (S) contains an acid anhydride of the compound (C), the compound (D) is a carboxyl initiates or promotes reaction with the group.

Suitable examples of compound (D) include acid compounds. The acid compound is a catalyst for the reaction between the oxazoline group of the oxazoline group-containing polymer (A) and the carboxyl group of the compound (C) and/or the carboxyl group generated by hydrolysis of the acid anhydride of the compound (C). It may be a compound that functions as

Examples of the acid compound include inorganic acids such as sulfuric acid, hydrogen chloride, nitric acid, phosphoric acid, phosphorous acid and boric acid; Organic acids such as phenylphosphoric acid, sulfanilic acid, phenylphosphonic acid, acetic acid and propionic acid can be mentioned.

The curable composition (S) may contain one compound (D), or may contain two or more compounds (D).

The compound (D) may be incorporated into the curable composition (S) as a solution (eg, aqueous solution) containing the compound (D).

Among them, the compound (D) contributes to the wet heat durability of the optical laminate, the adhesion between the optical film and the first cured layer in the optical laminate, and the adhesion between the first cured layer and the first thermoplastic resin film. A relatively strong acid is preferred from the viewpoint of enhancing the adhesion of the acid compound, and examples of such an acid compound include sulfuric acid, hydrogen chloride (hydrochloric acid), nitric acid, p-toluenesulfonic acid, and the like.

When a strong acid as described above is used as the compound (D), the adhesion between the optical film and the first cured layer in the optical laminate, and the adhesion between the first cured layer and the first thermoplastic resin film It tends to improve the adhesion of the adhesive.

The content of the compound (D) in the curable composition (S) is usually 1 part by mass or more and 150 parts by mass or less with respect to 100 parts by mass of the oxazoline group-containing polymer (A). from the viewpoint of improving the properties, the adhesion between the optical film and the first cured layer in the optical laminate, and the adhesion between the first cured layer and the first thermoplastic resin film, preferably 3 parts by mass or more. It is 100 parts by mass or less, more preferably 5 parts by mass or more and 100 parts by mass or less, and still more preferably 10 parts by mass or more and 100 parts by mass or less.

In one preferred embodiment, the content of the compound (D) is 10 parts by mass or more and 80 parts by mass or less with respect to 100 parts by mass of the oxazoline group-containing polymer (A) from the viewpoint of enhancing the wet heat durability of the optical laminate. Or it is 10 mass parts or more and 50 mass parts or less.

If the content of the compound (D) is excessively low, it is difficult to obtain the effect of increasing the wet heat durability of the optical layered body by containing the compound (D). In addition, if the content of the compound (D) is excessively small, the effect of increasing the adhesion between the optical film and the first cured product layer in the optical laminate due to the inclusion of the compound (D), It is difficult to obtain the effect of increasing the adhesion between the material layer and the first thermoplastic resin film.

If the content of the compound (D) is excessively high, the adhesion between the optical film and the first cured layer in the optical laminate, and the adhesion between the first cured layer and the first thermoplastic resin film At least one of the sexes tends to decline.

[5] Other components The curable composition (S) comprises an oxazoline group-containing polymer (A), an iodine compound (B), a compound (C), an acid anhydride of the compound (C) and a compound other than the compound (D). Other ingredients can be included.

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

The curable composition (S) can contain one or more other components.
The curable composition (S) preferably contains a solvent. Solvents include water, organic solvents, or mixtures thereof. The solvent preferably contains water, but water and a water-soluble organic solvent may be used in combination. Organic solvents include alcohol solvents such as ethanol and 1-methoxy-2-propanol.

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

The solid content concentration of the curable composition (S) is generally 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 be used as a coating liquid for forming a coating film (coating layer) on a substrate. For example, a coating film can be formed by coating the curable composition (S) on a substrate and curing the coating layer. The substrate is preferably an optical film. The optical film will be described later. In this case, the optical layered body includes an optical film and a first cured material layer composed of a cured material of the curable composition (S).

The curable composition (S) can also be used as an adhesive composition. In one embodiment, the curable composition (S) is an adhesive composition for bonding the optical film and the first thermoplastic resin film. In this case, the optical laminate includes, in this order, an optical film, a first cured layer (adhesive layer) composed of a cured product of the curable composition (S), and a first thermoplastic resin film. This optical laminate is obtained by applying a curable composition (S) to the bonding surface of at least one of the optical film and the first thermoplastic resin film, and After laminating a resin film to obtain a laminate, it can be produced by curing the coating layer.

The optical laminate is preferably a polarizing plate in which the optical film is a polarizer. A polarizing plate is an optical laminate including a polarizer and a first cured layer (a cured layer composed of a cured material of the curable composition (S)) laminated on at least one surface of the polarizer. .

The curable composition (S), which is an adhesive composition, is preferably an adhesive composition for polarizing plate, that is, an adhesive composition used for producing a polarizing plate. In this case, the curable composition (S) is used, for example, to bond the polarizer and the first thermoplastic resin film.

The curable composition (S) is preferably a water-based composition. That is, the curable composition (S) is preferably a solution in which the ingredients are dissolved in a solvent containing water, or a dispersion (e.g., an emulsion) in which the ingredients 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 more preferred. If the viscosity at 25° C. exceeds 50 mPa·sec, uniform coating may become difficult, and uneven coating may occur, and problems such as clogging of pipes may occur.

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

<Optical laminate>
The optical laminate according to the present invention includes an optical film and a first cured layer (a cured layer composed of a cured material of the curable composition (S)) laminated on at least one surface of the optical film.

According to the present invention, since the cured product layer contained in the optical layered body is composed of the cured product of the curable composition (S), the wet heat durability of the optical layered body can be improved.

[1] Structure of Optical Layered Body FIGS. 1 to 5 show examples of the layer structure of the optical layered body.

The optical laminate shown in FIG. 1 includes an optical film 30 and a first cured material layer 15 laminated on one surface thereof. The first cured product layer 15 can function as an overcoat layer that covers and protects the surface of the optical film 30, an optical function layer that additionally imparts an optical function to the optical film 30, and the like.

It is preferable that the optical film 30 and the first cured material layer 15 are in direct contact with each other.
The optical laminate shown in FIG. 2 includes an optical film 30 and a first thermoplastic resin film 10 laminated and bonded to one surface thereof with a first cured material layer 15 interposed therebetween. The first cured product layer 15 can function as an adhesive layer that bonds the optical film 30 and the first thermoplastic resin film 10 together.

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

It is preferable that the optical film 30 and the first cured material layer 15 are in direct contact with each other.
The optical layered body shown in FIG. and a second thermoplastic resin film 20 that is laminated and bonded with a second cured material layer 25 interposed in the second thermoplastic resin film 20 . That is, the optical laminate according to the present invention includes the second thermoplastic resin film 20, the second cured layer 25, the optical film 30, the first cured layer 15, and the first thermoplastic resin film 10 in this order. may be The first cured layer 15 and the second cured layer 25 respectively bond the optical film 30 and the first thermoplastic resin film 10 together, and the optical film 30 and the second thermoplastic resin film 20 together. It can function as an adhesive layer.

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

It is preferable that the optical film 30 and the first cured material layer 15 are in direct contact with each other.
It is preferable that the second cured layer 25 and the second thermoplastic resin film 20 are in direct contact with each other.

The optical film 30 and the second cured material layer 25 are preferably in direct contact.
The optical laminate shown in FIG. 4 includes an optical film 30, a first cured layer 15 laminated on one side of the optical film 30, and a second cured layer 25 on the other side of the optical film 30. and a second thermoplastic resin film 20 to be combined. The first cured product layer 15 can function as an overcoat layer that covers and protects the surface of the optical film 30, an optical function layer that additionally imparts an optical function to the optical film 30, and the like. The second cured layer 25 can function as an adhesive layer that bonds the optical film 30 and the second thermoplastic resin film 20 together.

It is preferable that the optical film 30 and the first cured material layer 15 are in direct contact with each other.
It is preferable that the second cured layer 25 and the second thermoplastic resin film 20 are in direct contact with each other.

The optical film 30 and the second cured material layer 25 are preferably in direct contact.
The optical laminate shown in FIG. 5 includes an optical film 30, a first cured layer 15 laminated on one side thereof, and a second cured layer 25 laminated on the other side of the optical film 30. include. The first cured layer 15 and the second cured layer 25 function as an overcoat layer that covers and protects the surface of the optical film 30, an optical function layer that additionally imparts an optical function to the optical film 30, and the like. can be done.

It is preferable that the optical film 30 and the first cured material layer 15 are in direct contact with each other.
The optical film 30 and the second cured material layer 25 are preferably in direct contact.

The optical film 30 may be various optical films (films having optical properties) that can be incorporated in an image display device such as a liquid crystal display device. Examples of the optical film 30 include a polarizer, a retardation film, a brightness enhancement film, an antiglare film, an antireflection film, a diffusion film, and a light collecting film.

The optical laminate can contain layers (or films) other than those described above. Other layers include, for example, the first thermoplastic resin film 10, the second thermoplastic resin film 20, the first cured layer 15, the second cured layer 25 and/or the adhesive laminated on the outer surface of the optical film 30. Agent layer; separate film laminated on the outer surface of the pressure-sensitive adhesive layer (also referred to as "release film"); first thermoplastic resin film 10, second thermoplastic resin film 20, first cured material layer 15, second Protective film laminated on the outer surface of the cured layer 25 and/or the optical film 30 (also referred to as a "surface protection film"); first thermoplastic resin film 10, second thermoplastic resin film 20, first cured layer 15, the second cured material layer 25 and/or the optical functional film (or layer) laminated on the outer surface of the optical film 30 via an adhesive layer or a pressure-sensitive adhesive layer.

[2] Polarizer A polarizer is a layer or film having a function of selectively transmitting linearly polarized light in one direction from natural light.

Examples of the polarizer include a film obtained by adsorbing and aligning a dichroic dye on a polyvinyl alcohol-based resin film. Examples of dichroic dyes include iodine and dichroic organic dyes.

Also, the polarizer may be a coated polarizing film in which a base film is coated with a dichroic dye in the lyotrovic liquid crystal state and then oriented and fixed.

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

The polarizer is not limited to an absorptive polarizer, and may be a reflective polarizer that selectively transmits linearly polarized light in one direction from natural light and reflects linearly polarized light in another direction, or linearly polarized light in another direction. A scattering-type polarizer that scatters may be used, but an absorption-type polarizer is preferable from the viewpoint of excellent visibility. Among them, a polyvinyl alcohol-based polarizing film composed of a polyvinyl alcohol-based resin film is more preferable. More preferably, a polyvinyl alcohol polarizing film obtained by adsorbing and orienting iodine on a polyvinyl alcohol resin film is particularly preferable.

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

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

A film obtained by forming such a polyvinyl alcohol-based resin is used as a raw film for a polarizing film composed of a polyvinyl alcohol-based resin film. A method for forming a polyvinyl alcohol-based resin into a film is not particularly limited, and a known method is employed. The thickness of the polyvinyl alcohol-based raw film is, for example, 150 μm or less, preferably 100 μm or less (eg, 50 μm or less), and 5 μm or more.

A polarizing film composed of a polyvinyl alcohol-based resin film can be produced by a known method. Specifically, the process of uniaxially stretching the polyvinyl alcohol resin film; the process of dyeing the polyvinyl alcohol resin film with a dichroic dye to adsorb the dichroic dye; the polyvinyl alcohol adsorbed with the dichroic dye It can be produced by a method including a step of treating (crosslinking) a system resin film with an aqueous boric acid solution; and a step of washing with water after the treatment with an aqueous boric acid solution.

The thickness of the polarizer can be 40 μm or less, preferably 30 μm or less (eg, 20 μm or less, further 15 μm or less, still 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, a thin film polarizer can be more easily produced, and the thickness of the polarizer can be set to, for example, 20 μm or less, or even 15 μm. Below, it becomes easier to set the thickness to 10 μm or less or 8 μm or less. The thickness of the polarizer is usually 2 μm or more. Reducing the thickness of the polarizer is advantageous for thinning the optical layered body (polarizing plate) and the image display device including the same.

[3] Retardation film As the retardation film, a stretched film obtained by uniaxially or biaxially stretching a translucent thermoplastic resin; Examples thereof include those in which the above liquid crystal layer is formed on a material film. In this specification, a zero retardation film is also included in the retardation film.

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 translucent thermoplastic resins include resins that constitute the first thermoplastic resin film 10 described later.

A zero retardation film is a film having an in-plane retardation value R _e and a thickness direction retardation value R _th of −15 to 15 nm. This retardation film is suitably used for an IPS mode liquid crystal display device. Both the in-plane retardation value R _e and the thickness direction retardation value R _th are preferably −10 to 10 nm, more preferably −5 to 5 nm. The in-plane retardation value R _e and the thickness direction retardation value R _th herein are values at a wavelength of 590 nm.

The in-plane retardation value Re and the thickness direction retardation value Rth are calculated by the following formulas:
R _e =(n _x −n _y )×d
R _th =[(n _x +n _y )/2−n _z ]×d
defined by In the formula, _nx is the refractive index in the slow axis direction (x-axis direction) in the film plane, and _ny is the fast axis direction in the film plane (y-axis direction perpendicular to the x-axis in the plane). is the refractive index, _nz is the refractive index in the film thickness direction (z-axis direction perpendicular to the film surface), and d is the thickness of the film.

For the zero retardation film, for example, a resin film made of polyolefin resin such as cellulose resin, chain polyolefin resin and cyclic polyolefin resin, polyethylene terephthalate resin or (meth)acrylic resin can be used. Cellulose-based resins, polyolefin-based resins, or (meth)acrylic-based resins are particularly preferably used because the retardation value can be easily controlled and they are easily available.

Films that exhibit optical anisotropy by applying and aligning liquid crystalline compounds include:
First form: A retardation film in which a rod-shaped liquid crystal compound is oriented horizontally with respect to a supporting substrate,
Second form: A retardation film in which a rod-shaped liquid crystal compound is oriented in a direction perpendicular to the support substrate,
Third form: A retardation film in which the direction of orientation of the rod-like liquid crystal compound changes in a helical manner within the plane,
Fourth mode: a retardation film in which a discotic liquid crystal compound is tilted,
Fifth form: A biaxial retardation film in which a discotic liquid crystal compound is oriented in a direction perpendicular to a supporting substrate.

For example, as an optical film used for an organic electroluminescence display, the first form, the second form, and the fifth form are preferably used. Alternatively, these may be laminated and used.

When the retardation film is a layer (hereinafter sometimes referred to as an "optically anisotropic layer") composed of a polymer in an aligned state of a polymerizable liquid crystal compound, the retardation film may have reverse wavelength dispersion. preferable. The reverse wavelength dispersion is an optical characteristic in which the liquid crystal alignment in-plane retardation value at a short wavelength is smaller than the liquid crystal alignment in-plane retardation value at a long wavelength. (1) and formula (2) are satisfied. Note that R _e (λ) represents an in-plane retardation value for light with a wavelength of λ nm.

R _e (450)/R _e (550)≦1 (1)
1≦ _Re (630)/ _Re (550) (2)
When the retardation film is in the first form and has reverse wavelength dispersion, it is preferable because coloring during black display on the display device is reduced, and in the formula (1), 0.82 ≤ R _e (450) / R _e It is more preferable if (550) ≤ 0.93. Furthermore, 120≦R _e (550)≦150 is preferable.

As the polymerizable liquid crystal compound when the retardation film is a film having an optically anisotropic layer, "3. .8.6 Network (completely crosslinked type)”, “6.5.1 Liquid crystal material b. JP, JP 2010-270108, JP 2011-6360, JP 2011-207765, JP 2016-81035, WO 2017/043438 and JP 2011-207765 and the polymerizable liquid crystal compound described in .

Examples of the method for producing a retardation film from the polymer in the oriented state of the polymerizable liquid crystal compound include the method described in JP-A-2010-31223.

In the case of the second embodiment, the in-plane retardation value R _e (550) may be adjusted in the range of 0 to 10 nm, preferably in the range of 0 to 5 nm, and the thickness direction retardation value R _th is −10. It may be adjusted in the range of -300 nm, preferably in the range of -20 to -200 nm.

The thickness direction retardation value R _th , which means the refractive index anisotropy in the thickness direction, is the retardation value R ₅₀ and the in-plane retardation value measured by tilting the in-plane fast axis by 50 degrees as the tilt axis. It can be calculated from R _e . That is, the retardation value R _th in the thickness direction is the in-plane retardation value R _e , the retardation value R ₅₀ measured by tilting the fast axis by 50 degrees, the thickness d of the retardation film, and the phase difference value R 50 . From the average refractive index n ₀ of the retardation film, n _x , n _y and n _z are determined by the following formulas (4) to (6), and these can be substituted into the formula (3) for calculation.

R _th =[(n _x +n _y )/2−n _z ]×d (3)
R _e =(n _x −n _y )×d (4)
R ₅₀ = (n _x -n _y ') x d/cos(φ) (5)
( _nx + _ny + _nz )/3= _n0 (6)
here,
φ=sin ⁻¹ [sin (40°)/n ₀ ]
ny _′ = _ny × _nz /[ _ny ² ×sin ² (φ)+ _nz ² ×cos ² (φ)] ^1/2
The retardation film may be a multilayer film having two or more layers. Examples thereof include a retardation film laminated with a protective film on one side or both sides thereof, and a retardation film laminated with two or more retardation films via a pressure-sensitive adhesive or an adhesive.

[4] First Cured Material Layer The first cured material layer 15 is a cured material layer composed of a cured material of the curable composition (S). The curable composition (S) is as described above. The curable composition (S) can be cured by heat, for example.

[5] Thermoplastic resin film The first thermoplastic resin film 10 and the second thermoplastic resin film 20 are each a translucent (preferably optically transparent) thermoplastic resin, such as a chain polyolefin resin. Polyolefin resins such as (polypropylene resins, etc.), cyclic polyolefin resins (norbornene resins, etc.); cellulose ester resins such as triacetyl cellulose and diacetyl cellulose; polyester resins such as polyethylene terephthalate, polyethylene naphthalate and polybutylene terephthalate Resins; polycarbonate resins; (meth)acrylic resins; polystyrene resins;

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 can each be either unstretched films or uniaxially or biaxially stretched films. The biaxial stretching may be simultaneous biaxial stretching in which the film is simultaneously stretched in two stretching directions, or sequential biaxial stretching in which the film is stretched in a first direction and then in a second direction different from 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 optical film 30, or a protective film that also has an optical function such as a retardation film. can also

As for the retardation film, the description of [4] above is cited.
Examples of linear polyolefin resins include homopolymers of linear olefins such as polyethylene resins and polypropylene resins, as well as copolymers composed of two or more linear olefins.

Cyclic polyolefin-based resin is a general term for resins containing cyclic olefins, typically norbornene, tetracyclododecene (also known as dimethanooctahydronaphthalene), or derivatives thereof, as polymerized units. Cyclic polyolefin resins include ring-opening (co)polymers of cyclic olefins and hydrogenated products thereof, addition polymers of cyclic olefins, cyclic olefins and linear olefins such as ethylene and propylene, or aromatic compounds having a vinyl group. and modified (co)polymers obtained by modifying these with unsaturated carboxylic acids or derivatives thereof.

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

The cellulose ester resin is a resin in which at least a portion of the hydroxyl groups in cellulose is acetic ester, and is a mixed ester in which a portion is acetic ester and a portion is esterified with another acid. good too. The cellulose ester-based resin is preferably an acetylcellulose-based resin.

Acetyl cellulose resins include triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, and the like.

Polyester-based resins are resins other than the above cellulose ester-based resins, which have ester bonds, and are generally composed of polycondensates of polyhydric carboxylic acids or derivatives thereof and polyhydric alcohols.

Polyester-based resins include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethylterephthalate, polycyclohexanedimethylnaphthalate and the like.

Among them, polyethylene terephthalate is preferably used from the viewpoint of mechanical properties, solvent resistance, scratch resistance, cost, and the like. Polyethylene terephthalate refers to a resin in which 80 mol% or more of the repeating units are composed of ethylene terephthalate, and structural units derived from other copolymer components (dicarboxylic acid component such as isophthalic acid; diol component such as propylene glycol, etc.). may contain

Polycarbonate resins are polyesters formed from carbonic acid and glycol or bisphenol. Among them, an aromatic polycarbonate having a diphenylalkane in its molecular chain is preferably used from the viewpoint of heat resistance, weather resistance and acid resistance.

Polycarbonates include 2,2-bis(4-hydroxyphenyl)propane (also known as bisphenol A), 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1, Examples include polycarbonates derived from bisphenols such as 1-bis(4-hydroxyphenyl)isobutane, 1,1-bis(4-hydroxyphenyl)ethane and the like.

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

Methacrylate esters include methyl methacrylate, ethyl methacrylate, n-, i- or t-butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate. etc.

Acrylic acid esters 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 consisting only of structural units derived from (meth)acrylic monomers, or may contain other structural units.

In one preferred embodiment, the (meth)acrylic resin contains methyl methacrylate or methyl methacrylate and methyl acrylate as copolymer components.

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

The glass transition temperature of the (meth)acrylic resin is preferably 80°C or higher and 160°C or lower. The glass transition temperature depends on 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 and the type of functional group they have, and the polyfunctional monomer with respect to the entire monomer. It can be controlled by adjusting the polymerization ratio of the monomers.

As a means for increasing the glass transition temperature of (meth)acrylic resins, it is also effective to introduce a ring structure into the main chain of the polymer. The ring structure is preferably a heterocyclic structure such as a cyclic acid anhydride structure, a cyclic imide structure and a lactone structure. Specific examples include cyclic acid anhydride structures such as glutaric anhydride structure and succinic anhydride structure; cyclic imide structures such as glutarimide structure and succinimide structure; and lactone ring structures such as butyrolactone and valerolactone.

There is a tendency that the larger the content of the ring structure in the main chain, the higher the glass transition temperature of the (meth)acrylic resin.

A cyclic acid anhydride structure and a cyclic imide structure are introduced by copolymerizing monomers having a cyclic structure such as maleic anhydride and maleimide; Method of introduction: It can be introduced by, for example, a method of reacting an amino compound to introduce a cyclic imide structure.

A resin (polymer) having a lactone ring structure is obtained by preparing a polymer having a hydroxyl group and an ester group in the polymer chain, and then heating the hydroxyl group and the ester group in the resulting polymer, if necessary. Accordingly, 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 therefrom may contain additives as necessary. Examples of additives include lubricants, antiblocking agents, heat stabilizers, antioxidants, antistatic agents, light stabilizers, impact modifiers, surfactants, and the like.

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

The (meth)acrylic resin may contain acrylic rubber particles as an impact modifier from the viewpoint of the film formability of the film, the impact resistance of the film, and the like. Acrylic rubber particles are particles containing an elastic polymer mainly composed of acrylic acid ester as an essential component. A multi-layered structure may be mentioned.

Examples of the elastic polymer include a crosslinked elastic copolymer having an alkyl acrylate as a main component and copolymerized with another copolymerizable vinyl-based monomer and a crosslinkable monomer.

Examples of the alkyl acrylate, which is the main component of the elastic polymer, include alkyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc., in which the number of carbon atoms in the alkyl group is about 1 to 8. and an alkyl acrylate having an alkyl group having 4 or more carbon atoms is preferably used.

Examples of other vinyl-based monomers copolymerizable with the alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, more specifically, methyl methacrylate. aromatic vinyl compounds such as styrene; vinyl cyanide compounds such as acrylonitrile;

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, butane polyhydric alcohol (meth)acrylates 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 the optical film 30. can also In addition, a (meth)acrylic resin layer is formed on one or both sides of the retardation layer made of a resin different from the (meth)acrylic resin, and the phase difference is exhibited. It can also be a thermoplastic resin film.

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

The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 includes ultraviolet absorbers, infrared absorbers, organic dyes, pigments, inorganic dyes, antioxidants, antistatic agents, surfactants, lubricants, It may contain a dispersant, a heat stabilizer, and the like. When the optical laminate is applied to an image display device, a thermoplastic resin film containing an ultraviolet absorber is arranged on the viewing side of an image display element (for example, a liquid crystal cell, an organic EL display element, etc.), so that the image display element Degradation due to ultraviolet rays can be suppressed.

Examples of ultraviolet absorbers include salicylate compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, nickel complex compounds, and the like.

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be films composed of the same thermoplastic resin, or may be films composed 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, the presence or absence of additives, their types, retardation properties, 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 diffusion layer, and an electrification layer on its outer surface (the surface opposite to the optical film 30). A surface treatment layer (coating layer) such as an antifouling layer, an antifouling layer, and a conductive layer may be provided.

Each of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 has a thickness of 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, further preferably 15 μm or more and 65 μm or less. is. Each of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 may have a thickness of 50 μm or less, or 40 μm or less. Reducing the thickness of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is advantageous for thinning the optical laminate (polarizing plate) and the image display device including the same.

From the viewpoint of improving adhesion, the surfaces of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 on which the curable composition is applied are subjected to saponification treatment, plasma treatment, corona treatment, primer treatment, or the like. The surface modification treatment may be performed, or the surface modification treatment may not be performed from the viewpoint of simplification of the process. The surface modification treatment may be performed on the bonding surface of the optical film 30 instead of the bonding surface of the thermoplastic resin film, or together with the bonding surface.

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

[6] Second cured layer The curable composition forming the second cured layer 25 may be the curable composition (S) described above, or may be another curable composition different from this. There may be. The second cured layer 25 is preferably a cured layer of the curable composition (S) from the viewpoint of wet heat durability of the optical layered body.

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

Other curable compositions include known water-based compositions (including water-based adhesives) in which a curable resin component is dissolved or dispersed in water, and known active energy rays containing active energy ray-curable compounds. curable compositions (including active energy ray-curable adhesives);

Examples of the resin component contained in the water-based composition include polyvinyl alcohol-based resins and urethane resins.

Water-based compositions containing polyvinyl alcohol resins contain curable components such as polyhydric aldehydes, melamine compounds, zirconia compounds, zinc compounds, glyoxal, glyoxal derivatives, and water-soluble epoxy resins in order to improve adhesion and adhesiveness. or a cross-linking agent.

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

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

The active energy ray-curable composition can be a composition containing, as a curable component, an epoxy-based compound that cures by cationic polymerization, and is preferably an ultraviolet-curable composition containing such an epoxy-based compound as a curable component. It is a thing. An epoxy-based compound means a compound having an average of one or more, preferably two 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 hydrogenated epoxy compound (having an alicyclic ring) obtained by reacting an alicyclic polyol obtained by hydrogenating the aromatic ring of an aromatic polyol with epichlorohydrin polyol glycidyl ether); aliphatic epoxy compounds such as polyglycidyl ethers of aliphatic polyhydric alcohols or their alkylene oxide adducts; epoxy compounds having one or more epoxy groups bonded to an alicyclic ring in the molecule Certain alicyclic epoxy compounds and the like can be mentioned.

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

When the active energy ray-curable composition contains an epoxy-based compound that cures by cationic polymerization as a curable component, it preferably contains a photocationic polymerization initiator. Examples of photocationic polymerization initiators 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 composition contains a radically polymerizable component such as a (meth)acrylic compound, it preferably contains a radical photopolymerization initiator. Examples of radical photopolymerization initiators include acetophenone-based initiators, benzophenone-based initiators, benzoin ether-based initiators, thioxanthone-based initiators, xanthone, fluorenone, camphorquinone, benzaldehyde, and anthraquinone.

The optical layered body may include an adhesive layer instead of the second cured layer 25 . That is, the second thermoplastic resin film 20 may be attached to the optical film 30 via an adhesive layer. As for the pressure-sensitive adhesive layer, the description of the pressure-sensitive adhesive layer to be described later is cited.

[7] Production of Optical Laminate By laminating and adhering the first thermoplastic resin film 10 to one surface of the optical film 30 with the first cured material layer 15 interposed therebetween, an optical laminate having the configuration shown in FIG. By further laminating and bonding the second thermoplastic resin film 20 to the other surface of the optical film 30 via the second cured material layer 25, an optical laminate having the configuration shown in FIG. 3 can be obtained. can be done.

When manufacturing an optical laminate having both the first thermoplastic resin film 10 and the second thermoplastic resin film 20, these films may be laminated and bonded stepwise one side at a time, or the films on both sides may be laminated and bonded at the same time. Lamination adhesion may be used.

As a method for bonding the optical film 30 and the first thermoplastic resin film 10, the curable composition (S) is applied to either one or both of the bonding surfaces of the optical film 30 and the first thermoplastic resin film 10. For example, a method of applying a coating, laminating the other bonding surface on this, and bonding by pressing from above and below using a bonding roll or the like can be mentioned.

Various coating methods such as doctor blade, wire bar, die coater, comma coater, and gravure coater can be used to apply the curable composition (S). Alternatively, the method may be such that the curable composition (S) is cast while the optical film 30 and the first thermoplastic resin film 10 are continuously supplied so that the bonding surfaces of the two are on the inside. good.

After laminating the optical film 30 and the first thermoplastic resin film 10, the laminate including the optical film 30, the first cured material layer 15, and the first thermoplastic resin film 10 is subjected to heat treatment. is preferred. 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 heat treatment can remove the solvent contained in the curable composition layer. In addition, the heat treatment can promote the curing and cross-linking reaction of the curable composition.

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

When using an active energy ray-curable composition as the curable composition constituting the second cured material layer, after drying the curable composition layer as necessary, the curable composition is irradiated with an active energy ray. Harden the material layer.

The light source used for irradiating the active energy ray may be one that can generate 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, etc., which have an emission distribution at a wavelength of 400 nm or less, are preferably used.

An optical laminate having no first thermoplastic resin film on the first cured material layer 15, as shown in FIG. 1, was obtained by coating the surface of the optical film 30 with the curable composition (S) It can be produced by subjecting the laminate to heat treatment at 80° C. for 300 seconds, for example, using a hot air dryer. Alternatively, the optical laminate shown in FIG. 1 is also produced by producing a laminate consisting of a separate film/curable composition (S)/optical film 30, peeling off the separate film, and then performing a heat treatment. be able to.

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 even more preferably. is 20 nm or more and 1 μm or less. A cured product layer formed from the above-described known water-based composition can also have a similar thickness.

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

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

[8] Other components of optical laminate [8-1] Optical functional film A film can be provided, a suitable example of which 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 the first thermoplastic resin film 10, the second thermoplastic resin film 20, the first cured layer 15 and/or the second cured layer 25 via the adhesive layer or the adhesive layer. can be laminated to the outer surface of the As for the retardation film, the description of [4] above is cited.

Examples of other optical functional films (optical members) that can be included in optical laminates such as polarizing plates include light collectors, brightness enhancement films, reflective layers (reflective films), semi-transmissive reflective layers (semi-transmissive reflective films), A light diffusion layer (light diffusion film) or the like.

The light collecting plate is used for the purpose of optical path control, etc., and can be a prism array sheet, a lens array sheet, a dot-attached sheet, or the like.

A brightness enhancement film is used for the purpose of improving brightness in an image display device to which an optical laminate such as a polarizing plate is applied. Specifically, a reflective polarization separation sheet designed to generate anisotropy in reflectance by laminating multiple thin films with different refractive index anisotropy, an oriented film of cholesteric liquid crystal polymer, and its orientation A circularly polarized light separation sheet having a liquid crystal layer supported on a substrate film, and the like.

The reflective layer, the semi-transmissive reflective layer, and the light diffusion layer are provided to make the polarizing plate into a reflective, semi-transmissive, and diffusive optical member, respectively. A reflective polarizing plate is used in a liquid crystal display device that reflects incident light from the viewing side for display, and can omit a light source such as a backlight, so that the liquid crystal display device can be easily made thinner. A semi-transmissive polarizing plate is used in a type of liquid crystal display device in which a reflective type is used in a bright place and light from a backlight is used in a dark place. Diffusion-type polarizing plates are used in liquid crystal display devices in which display defects such as moire are suppressed by imparting light diffusion properties. The reflective layer, transflective layer and light diffusion layer can be formed by known methods.

[8-2] Adhesive layer The optical layered body can contain an adhesive layer. Examples of the pressure-sensitive adhesive layer include a pressure-sensitive adhesive layer for bonding the optical laminate to an image display element such as a liquid crystal cell or an organic EL display element, or another optical member. The pressure-sensitive adhesive layer is the outer surface of the optical film 30 in the optical laminate having the structure shown in FIGS. 1 and 2, and the first thermoplastic resin film 10 or the second thermoplastic The outer surface of the resin film 20, the outer surface of the first cured material layer 15 or the second thermoplastic resin film 20 in the optical laminate having the configuration shown in FIG. 4, and the first curing in the optical laminate having the configuration shown in FIG. It can be laminated on the outer surface of the material layer 15 or the second cured material layer 25 .

FIG. 6 shows an example in which an adhesive layer 40 is laminated on the outer surface of the second thermoplastic resin film 20 of the optical layered body having the structure shown in FIG.

As the adhesive used in the adhesive layer, one using a (meth)acrylic resin, silicone resin, polyester resin, polyurethane resin, polyether resin, or the like as a base polymer can be used. Among them, (meth)acrylic pressure-sensitive adhesives are preferable from the viewpoint 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 a (meth) A weight-average molecular weight obtained by blending acrylic acid and a (meth)acrylic monomer containing a functional group such as hydroxyethyl (meth)acrylate so that the glass transition temperature is preferably 25° C. or less, more preferably 0° C. or less. A (meth)acrylic resin having a is of 100,000 or more is useful as a base polymer.

The formation of the adhesive layer on the optical layered body is performed by, for example, dissolving or dispersing the adhesive composition in an organic solvent such as toluene or ethyl acetate to prepare an adhesive liquid, which is directly applied to the target surface of the optical layered body. A method in which an adhesive layer is formed by coating, a method in which a sheet-like adhesive layer is formed on a release-treated separate film, and then transferred to the target surface of the optical laminate, etc. It can be done by

The thickness of the pressure-sensitive adhesive layer is determined according to its adhesive strength and the like, and is suitably in the range of 1 µm to 50 µm, preferably 2 µm to 40 µm.

The optical laminate may contain the above 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. Among them, a stretched film of polyethylene terephthalate is preferable.

The pressure-sensitive adhesive layer optionally contains glass fibers, glass beads, resin beads, fillers made of metal powders or other inorganic powders, pigments, colorants, antioxidants, ultraviolet absorbers, antistatic agents, etc. be able to.

[8-3] Protective film The optical laminate has a surface (typically, the first thermoplastic resin film 10, the second thermoplastic resin film 20, the first cured layer 15 and/or the second cured layer 25 surface) can be included. The protective film is peeled off together with the pressure-sensitive adhesive layer, for example, after the optical laminate is attached to an image display element or other optical member.

The protective film is composed of, for example, a base film and an adhesive layer laminated thereon. As for the pressure-sensitive adhesive layer, the above description is cited.

The resin constituting the base film is, for example, a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, a polyester-based resin such as polyethylene terephthalate or polyethylene naphthalate, or a thermoplastic resin such as a polycarbonate-based resin. be able to. Polyester-based resins such as polyethylene terephthalate are preferred.

<Image display device>
The optical layered body according to the present invention can be applied to an image display device. In this case, the image display device includes an optical layered body and an image display element. Examples of image display elements include liquid crystal cells and organic EL display elements. Conventionally known devices can be used as these image display devices.

When the optical layered body which is a polarizing plate is applied to a liquid crystal display device, the optical layered body may be arranged on the backlight side (back side) of the liquid crystal cell, or may be arranged on the viewing side, It may be placed in both of them. When an optical layered body that is a polarizing plate is applied to an organic EL display device, the optical layered body is usually arranged on the viewing side of the organic EL display element.

EXAMPLES 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, percentages and parts representing contents or usage amounts are based on mass unless otherwise specified.

In Table 1, the oxazoline group-containing polymer (A), the iodine compound (B), the compound (C) having a carboxyl group, and the Compounds (D) that accelerate the reaction are abbreviated as (A), (B), (C), and (D), respectively.

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

<Examples 1 to 6, Comparative Example 1>
(1) Preparation of Curable Composition Components shown in Table 1 were mixed in the amounts shown in Table 1 together with pure water as a solvent to prepare a curable composition (aqueous adhesive solution). The unit of the compounding amount of each component shown in Table 1 is parts by mass, and the compounding amount of each component is the amount in terms of solid content. The concentration of (A) in the curable composition obtained in Example 1 was 4.0% by mass, and the concentration of (A) in the curable composition of Example 2 was 5.0% by mass. The concentration of (A) in the curable composition of 3 is 6.0% by mass, the concentration of the curable composition (A) in the curable compositions of Examples 4 and 5 is 7.0% by mass, The concentration of (A) in the curable composition No. 6 was set to 5.0% by mass. In Comparative Example 1, the concentration of (X) in the curable composition was 3.0% by mass.

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

(3) Evaluation of optical durability (wet heat durability) After cutting the obtained polarizing plate into a size of 30 mm × 30 mm, it was attached to a glass substrate via a (meth)acrylic adhesive on the zero retardation film side. were combined to obtain a measurement sample. The layer structure of the measurement sample was glass substrate/(meth)acrylic adhesive layer/zero retardation film/cured layer/polarizer/cured layer/TAC film. A non-alkali glass substrate (trade name “Eagle XG” manufactured by Corning Incorporated) was used as the glass substrate.

For the obtained measurement sample, the MD transmittance and TD transmittance in the wavelength range of 380 to 780 nm were measured using a spectrophotometer with an integrating sphere [manufactured by JASCO Corporation, product name "V7100"]. was calculated. The calculated degree of polarization was subjected to visual sensitivity correction using a 2-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”, and subjected to a humidity and heat durability test. The previous visibility-corrected polarization degree Py was determined. The sample to be measured was set in a spectrophotometer with an integrating sphere so that the TAC film side of the polarizing plate was on the detector side and light was incident from the glass substrate side.

The degree of polarization (%) is calculated using the following formula:
Degree of polarization (λ) = 100 × (Tp (λ) - Tc (λ)) / (Tp (λ) + Tc (λ))
defined by

Tp(λ) is the transmittance (%) of the measurement sample measured in relation to the incident linearly polarized light of wavelength λ (nm) and parallel Nicols.

Tc(λ) is the transmittance (%) of the measurement sample measured in relation to the incident linearly polarized light of wavelength λ (nm) and crossed Nicols.

Next, after placing this measurement sample in a high temperature and high humidity environment with a temperature of 85 ° C. and a relative humidity of 85% RH for 500 hours, it was placed in an environment with a temperature of 23 ° C. and a relative humidity of 50% RH for 24 hours. . After the wet heat durability test, the visibility-corrected polarization degree Py was obtained by the same method as before the wet heat durability test.

The absolute value (|ΔPy|) of the difference between the visibility-corrected polarization degree Py after the wet-heat durability test and the visibility-corrected polarization degree Py before the wet-heat durability test was calculated.

Next, from the obtained value of |ΔPy|, the "ΔPy change rate" (%) of each example based on |ΔPy| of Comparative Example 1 was obtained based on the following formula. Table 1 shows the calculated values of the ΔPy rate of change. The higher the ΔPy change rate, the better the wet heat durability.

ΔPy change rate (%) of each example
= 100 × | {(|ΔPy| of each example)−(|ΔPy| of Comparative Example 1)}|/(|ΔPy| of Comparative Example 1)
ΔPy showed a negative value in any of the examples and comparative examples.

Details of each component shown in Table 1 are as follows.
a1: Trade name “Epocross WS-300” manufactured by Nippon Shokubai Co., Ltd. [Aqueous solution of oxazoline group-containing acrylic polymer having 2-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: zinc iodide (ZnI ₂ )
b2: titanium iodide (TiI ₄ )
c1: citric acid d1: sulfuric acid x1: trade name “GOSEFIMER Z-200” manufactured by The Nippon Synthetic Chemical Industry Co., Ltd. [acetoacetyl group-modified polyvinyl alcohol, average degree of polymerization: 1100, degree of saponification: 98.5 mol% that's all〕
y1: glyoxal <Examples 7 to 11>
(1) Preparation of Curable Composition The components shown in Table 2 were mixed in the amounts shown in Table 2 together with pure water as a solvent to prepare a curable composition (aqueous adhesive solution). The unit of the blending amount of each component shown in Table 2 is parts by mass, and the blending amount of each component is the amount in terms of solid content. The concentration of (A) in the curable composition obtained in Example 7 was 8.0% by mass, and the concentration of (A) in the curable compositions of Examples 8 and 10 was 5.0 mass. %, and the concentration of (A) in the curable compositions of Examples 9 and 11 was 7.0% by mass.

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

(3) Evaluation of optical durability (wet heat durability) After cutting the obtained polarizing plate into a size of 30 mm × 30 mm, it was attached to a glass substrate via a (meth)acrylic adhesive on the zero retardation film side. were combined to obtain a measurement sample. The layer structure of the measurement sample was glass substrate/(meth)acrylic adhesive layer/zero retardation film/cured layer/polarizer/cured layer/TAC film. A non-alkali glass substrate (trade name “Eagle XG” manufactured by Corning Incorporated) was used as the glass substrate.

For the obtained measurement sample, the MD transmittance and TD transmittance in the wavelength range of 380 to 780 nm were measured using a spectrophotometer with an integrating sphere [manufactured by JASCO Corporation, product name "V7100"]. was calculated. The calculated degree of polarization was subjected to visual sensitivity correction using a 2-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”, and subjected to a humidity and heat durability test. The previous visibility-corrected polarization degree Py was determined. The sample to be measured was set in a spectrophotometer with an integrating sphere so that the TAC film side of the polarizing plate was on the detector side and light was incident from the glass substrate side.

The degree of polarization (%) is calculated using the following formula:
Degree of polarization (λ) = 100 × (Tp (λ) - Tc (λ)) / (Tp (λ) + Tc (λ))
defined by

Tp(λ) is the transmittance (%) of the measurement sample measured in relation to the incident linearly polarized light of wavelength λ (nm) and parallel Nicols.

Tc(λ) is the transmittance (%) of the measurement sample measured in relation to the incident linearly polarized light of wavelength λ (nm) and crossed Nicols.

Next, after placing this measurement sample in a high temperature and high humidity environment with a temperature of 85 ° C. and a relative humidity of 85% RH for 500 hours, it was placed in an environment with a temperature of 23 ° C. and a relative humidity of 50% RH for 24 hours. . After the wet heat durability test, the visibility-corrected polarization degree Py was obtained by the same method as before the wet heat durability test.

The absolute value (|ΔPy|) of the difference between the visibility-corrected polarization degree Py after the wet-heat durability test and the visibility-corrected polarization degree Py before the wet-heat durability test was calculated.

Next, from the obtained value of |ΔPy|, the "ΔPy change rate" (%) of each example based on |ΔPy| of Comparative Example 1 was obtained based on the following formula. Table 1 shows the calculated values of the ΔPy rate of change. The higher the ΔPy change rate, the better the wet heat durability.

ΔPy change rate (%) of each example
= 100 × | {(|ΔPy| of each example)−(|ΔPy| of Comparative Example 1)}|/(|ΔPy| of Comparative Example 1)

Details of each component shown in Table 2 are as follows.
a1: Trade name “Epocross WS-300” manufactured by Nippon Shokubai Co., Ltd. [Aqueous solution of oxazoline group-containing acrylic polymer having 2-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: zinc iodide (ZnI ₂ )
b3: cesium iodide b4: ammonium iodide c1: citric acid d1: sulfuric acid

10 first thermoplastic resin film, 15 first cured layer, 20 second thermoplastic resin film, 25 second cured layer, 30 optical film, 40 adhesive layer.

Claims (6)

An optical laminate comprising an optical film and a first cured product layer composed of a cured product of a curable composition,
the optical film is a polarizer,
The curable composition includes at least one selected from the group consisting of an oxazoline group-containing polymer (A), an iodine compound (B), a compound (C) having a carboxyl group, and an acid anhydride of the compound (C). including one,
The oxazoline group-containing polymer (A) is an oxazoline group-containing (meth)acrylic polymer,
The iodine compound (B) is an iodide salt,
The optical laminate, wherein the compound (C) having a carboxyl group is at least one selected from the group consisting of citric acid, malic acid, maleic acid and tartaric acid. An optical laminate comprising an optical film and a first cured product layer composed of a cured product of a curable composition,
the optical film is a polarizer,
The curable composition includes at least one selected from the group consisting of an oxazoline group-containing polymer (A), an iodine compound (B), a compound (C) having a carboxyl group, and an acid anhydride of the compound (C). including one,
The oxazoline group-containing polymer (A) is an oxazoline group-containing (meth)acrylic polymer,
The iodine compound (B) is an iodide salt,
The compound (C) having a carboxyl group is a polyfunctional carboxylic acid compound,
The content of at least one selected from the group consisting of the compound (C) having a carboxyl group and the acid anhydride of the compound (C) is 1 part by mass with respect to 100 parts by mass of the oxazoline group-containing polymer (A) An optical layered body having a weight of 8 parts by mass or less. 3. The optical laminate according to claim 1, further comprising a compound (D) that promotes reaction between the oxazoline group of the oxazoline group-containing polymer (A) and the carboxyl group of the compound (C) having a carboxyl group. 4. The optical laminate according to any one of claims 1 to 3, comprising the optical film, the first cured material layer, and the first thermoplastic resin film in this order. 5. The optical laminate according to claim 4, comprising a second thermoplastic resin film, a second cured layer, the optical film, the first cured layer, and the first thermoplastic resin film in this order. . An image display device comprising the optical laminate according to any one of claims 1 to 5 and an image display element.

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