JPWO2019116968A1 - Curable composition, optical laminate and image display device - Google Patents

Abstract

A curable composition containing an oxazoline group-containing polymer (A), a zinc compound (B), and at least one selected from the group consisting of a compound (C) having a carboxyl group and an acid anhydride of the compound (C). , And an optical laminate containing an optical film and a first cured product layer composed of a cured product of the curable composition, and an image display device including the same.

Description

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

In recent years, image display devices have been developed for mobile device applications such as smartphones and tablet terminals and in-vehicle device applications such as car navigation systems. In such an application, since there is a possibility of being exposed to a harsher environment as compared with the conventional indoor TV application, it is an issue to improve the durability of the device.

Similarly, the optical members constituting the liquid crystal display device, for example, the optical laminate are also required to have durability. That is, the optical member incorporated in the liquid crystal display device or the like may be placed in a high temperature or high temperature and high humidity environment, or may be placed in an environment in which high temperature and low temperature are repeated. Even in these environments, it is required that the optical characteristics do not deteriorate.

Examples of the optical laminate include an optical laminate containing a cured product layer composed of a cured product of a curable composition. An example of such an optical laminate is a polarizing plate. For example, Japanese Unexamined Patent Publication No. 2009-008860 (Patent Document 1) discloses a polarizing plate in which a transparent protective film is laminated on a polarizing element via a cured product layer (adhesive layer).

JP-A-2009-008860

An object of the present invention is to provide a curable composition that exhibits good heat resistance (heat resistance) even in the harsh environment as described above.

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

The present invention provides the curable composition, the optical laminate, the image display device, and the adhesive composition for a polarizing plate shown below.

[1] With the oxazoline group-containing polymer (A),
Zinc compound (B) and
A curable composition comprising at least one selected from the group consisting of compound (C) having a carboxyl group and an acid anhydride of compound (C).

[2] The curable composition according to [1], further comprising a compound (D) that promotes 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. Stuff.

[3] An optical laminate comprising an optical film and a first cured product layer composed of a cured product of the curable composition according to [1] or [2].

[4] The optical laminate according to [3], which comprises the optical film, the first cured product layer, and the first thermoplastic resin film in this order.

[5] The second thermoplastic resin film, the second cured product layer, the optical film, the first cured product layer, and the first thermoplastic resin film are included in this order, according to [4]. Optical laminate.

[6] The optical laminate according to any one of [3] to [5], wherein the optical film is a polarizer.

[7] An image display device including the optical laminate according to any one of [3] to [6] and an image display element.

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

It is possible to provide a curable composition that exhibits good heat resistance even in the harsh environment as described above.

It is possible to provide an optical laminate containing a cured product layer composed of a cured product of a curable composition and having good heat resistance, and an image display device including the optical laminate.

It is the schematic sectional drawing which shows an example of the optical laminated body which concerns on this invention. It is schematic cross-sectional view which shows another example of the layer structure of the optical laminate which concerns on this invention. It is schematic cross-sectional view which shows another example of the layer structure of the optical laminate which concerns on this invention. It is schematic cross-sectional view which shows another example of the layer structure of the optical laminate which concerns on this invention. It is schematic cross-sectional view which shows another example of the layer structure of the optical laminate which concerns on this invention. It is schematic cross-sectional view which shows another example of the layer structure of the optical laminate which concerns on this invention.

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

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

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

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

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

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

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

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

The oxazoline group-containing polymer (A) may be a copolymer of an oxazoline group-containing monomer or a polymer containing an oxazoline group by modifying the side chain functional group of the polymer.

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

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

The weight average molecular weight of the oxazoline group-containing polymer (A) is preferably 5000 or more, and more preferably 10000 or more. The fact that the weight average molecular weight is in the above range means that the heat resistance of the optical laminate is improved, the adhesion between the optical film and the first cured product layer in the optical laminate, the first cured product layer and the first thermoplastic resin. It can be advantageous in terms of adhesion to the 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-equivalent value by gel permeation chromatography (GPC).

The amount of oxazoline groups (the number of moles of oxazoline groups per 1 g of solid content of the oxazoline group-containing polymer (A)) of the oxazoline group-containing polymer (A) is preferably 0.4 mmol / g · solid or more. If the amount of oxazoline groups is smaller than the above range, the heat resistance of the optical laminate may be disadvantageous. From this point of view, the amount of oxazoline groups in the oxazoline group-containing polymer is more preferably 3 mmol / g · solid or more, still more preferably 5 mmol / g · solid or more and 9 mmol / g · solid or less.

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

The oxazoline group-containing polymer (A) is preferably 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 Epocross WS-300, Epocross WS-500, and Epocross WS-700 (all trade names) manufactured by Nippon Catalyst Co., Ltd .; Epocross K-1000 series and Epocross manufactured by Nippon Catalyst Co., Ltd. Examples thereof include oxazoline group-containing acrylic / styrene polymers such as K-2000 series and Epocross RPS series (both are trade names).

The oxazoline group-containing polymer (A) can be used in combination of two or more.
The heat resistance and optical properties of the optical laminate, the adhesion between the optical film and the first cured product layer in the optical laminate, the adhesion between the first cured product layer and the first thermoplastic resin film, and the first From the viewpoint of water resistance of the 1-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% by mass or less, more preferably 20% by mass or more and 85% by mass or less. Keeping the content of the oxazoline group-containing polymer (A) within the above range improves the heat resistance of the optical laminate, the adhesion between the optical film and the first cured product layer in the optical laminate, and the first. It is preferable from the viewpoint of adhesion between the 1st cured product layer and the 1st 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] Zinc compound (B)
The zinc compound (B) is a compound containing a zinc element. The curable composition (S) may contain one kind of zinc compound (B), or may contain two or more kinds of zinc compounds (B).

Examples of the zinc compound (B) include the following.
a) Inorganic zinc salt Zinc fluoride, zinc chloride, zinc bromide, zinc iodide and other zinc halides;
Zinc Sulfate, Zinc Carbonate, Zinc Borate, Zinc Nitrate, Zinc Phosphate, Zinc Hydroxide, Zinc Ammonium Chloride, Zinc Aluminum Sulfate, Potassium Sulfate, Zinc Chromate, Zinc Stin, etc. b) Other Inorganic Zinc Compounds Oxide (zinc oxide);
Inorganic Zinc Complex c) Organic Zinc Salt Zinc Tirate, Zinc Acetate, Zinc Propionate, Zinc Stearate, Zinc Laurate, Zinc Laurate, Zinc Oleate, Zinc Adipate, Zinc Gluconate, Zinc Citrate, Zinc Hydroxyacetate , Organic acid zinc salts such as zinc benzoate, phosphoric acid ester zinc salt, etc. d) Other organic zinc compounds dimethyl zinc, diethyl zinc, diphenyl zinc, etc.;
The content of the organic zinc complex zinc compound (B) is usually 1 part by mass or more and 300 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 heat resistance of the optical laminate. It is 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, and further preferably 10 parts by mass or more and 150 parts by mass or less.

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

If the content of the zinc compound (B) is excessively small, it is difficult to obtain the effect of increasing the heat resistance of the optical laminate by containing the zinc compound (B). Further, when the content of the zinc compound (B) is excessively large, the adhesiveness between the optical film and the first cured product layer in the optical laminate and the adhesion between the first cured product layer and the first thermoplastic resin film are obtained. At least one of the adhesions between them tends to decrease.

[3] Compound (C) having a carboxyl group and an acid anhydride of the compound (C) The curable composition (S) is selected from an acid anhydride of the compound (C) having a carboxyl group and the compound (C). At least one can be further included. 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 referred to here also includes a derivative of the carboxyl group, but does not include the acid anhydride of the compound (C).

Derivatives of the carboxyl group include a carboxylate anion group. Examples of the cation that becomes the counter ion of the carboxylate anion group include metal ions such as lithium ion, sodium ion, and potassium ion; and organic cations such as ammonium ion, sulfonium ion, and phosphonium ion.

The curable composition (S) may contain one kind of compound (C) or may contain two or more kinds of compounds (C). The curable composition (S) may contain an acid anhydride of one kind of compound (C), or may contain an acid anhydride of two or more kinds of compound (C). The curable composition (S) may contain one or more compounds (C) and an acid anhydride of one or more compounds (C).

Among them, compound (C) has heat resistance of the optical laminate, adhesion between the optical film and the first cured product layer in the optical laminate, and between the first cured product layer and the first thermoplastic resin film. From the viewpoint of enhancing the adhesion and the water resistance of the first cured product layer, it is preferable that the compound has two or more carboxyl groups (or derivatives thereof) in the molecule (polyfunctional carboxylic acid compound).

An example of a polyfunctional carboxylic acid compound is a dicarboxylic acid compound. Examples of dicarboxylic acid compounds include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimeric acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, tartaric acid, glutamic acid, malic acid, and malein. Acid, fumaric acid, itaconic acid, muconic acid, 1,4-cyclohexanedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, 4,4'-biphenyldicarboxylic acid Examples thereof include acids, 2,5-pyridinedicarboxylic acid, 3,5-pyridinedicarboxylic acid, diphenylsulfonedicarboxylic acid, diphenylmethanedicarboxylic acid, oxaloacetate, methylfumaric acid, and 2,6-pyridinedicarboxylic acid.

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

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

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

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

From the viewpoint of heat resistance of the optical laminate, the number of carboxyl groups contained in 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. An example of the polymer is a carboxyl group-modified polymer. An example of a carboxyl group-modified polymer is a carboxyl group-modified polyvinyl alcohol-based polymer.

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

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

The polyvinyl alcohol-based polymer constituting the main chain of the carboxyl group-modified polyvinyl alcohol-based polymer is a vinyl alcohol homopolymer (completely saponified polyvinyl alcohol) obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate. Alternatively, it may be partially saponified polyvinyl alcohol), or a polyvinyl alcohol-based copolymer obtained by saponifying a copolymer of vinyl acetate and another monomer copolymerizable therewith. May be good.

Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.

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

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

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

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

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

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

The use of the compound (C) having a molecular weight of 1000 or less can be advantageous in increasing the heat resistance of the optical laminate. From the viewpoint of heat resistance of the optical laminate, the molecular weight of compound (C) is preferably 800 or less, more preferably 500 or less.

The molecular weight of the compound (C) is the heat resistance of the optical laminate, the adhesion between the optical film and the first cured product layer in the optical laminate, and the first cured product layer and the first thermoplastic resin film. From the viewpoint of the adhesion between the two, it is preferably 90 or more, and more preferably 100 or more.

Preferred examples of compound (C) are citric acid, malic acid, maleic acid and tartaric acid.
Examples of the acid anhydride of compound (C) include carboxylic acid anhydride. Examples of the carboxylic acid anhydride 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 based on 100 parts by mass of the oxazoline group-containing polymer (A) from the viewpoint of increasing the heat resistance of the optical laminate. It is 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, and even more preferably. Is 0.2 parts by mass or more and 15 parts by mass or less.

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). It is 10 parts by mass or less, 0.5 parts by mass or more and 10 parts by mass or less, 0.5 parts by mass or more and 8 parts by mass or less, or 1 part by mass or more and 8 parts by mass or less.

If the content of at least one selected from the acid anhydrides of compound (C) and compound (C) is too low, it contains at least one selected from the acid anhydrides of compound (C) and compound (C). It is difficult to obtain the effect of increasing the heat resistance of the optical laminate. Further, if the content of at least one selected from the compound (C) and the acid anhydride of the compound (C) is excessively large, the effect of increasing the heat resistance of the optical laminate tends to decrease.

[4] A compound (D) that promotes 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) can further contain a compound (D) that promotes 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)". The promotion referred to here includes the case of initiating the reaction.

When the curable composition (S) contains an acid anhydride of compound (C), compound (D) is a carboxyl in a carboxylic acid resulting from the hydrolysis of at least a portion of the acid anhydride of compound (C). Initiate or accelerate the reaction with the group.

Preferable 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, nitrate, phosphoric acid, phobic acid, and boric acid; p-toluene sulfonic acid, dodecylbenzene sulfonic acid, naphthalene sulfonic acid, methane sulfonic acid, and benzene sulfonic acid. Examples thereof include organic acids such as phenylphosphoric acid, sulfanic acid, phenylphosphonic acid, acetic acid and propionic acid.

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

Compound (D) may be added to the curable composition (S) as a solution (for example, an aqueous solution) containing compound (D).

Among them, compound (D) has heat resistance of the optical laminate, adhesion between the optical film and the first cured product layer in the optical laminate, and between the first cured product layer and the first thermoplastic resin film. From the viewpoint of enhancing adhesion, a relatively strong acid is preferable, and examples of such an acid compound include sulfuric acid, hydrogen chloride (hydrochloric acid), nitric acid, p-toluenesulfonic acid and the like.

When the above-mentioned strong acid is used as the compound (D), the adhesion between the optical film and the first cured product layer and the space between the first cured product layer and the first thermoplastic resin film are particularly high in the optical laminate. It tends to improve the adhesion of the plastic.

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), and the heat resistance of the optical laminate. From the viewpoint of enhancing the adhesion between the optical film and the first cured product layer in the optical laminate and the adhesion between the first cured product layer and the first thermoplastic resin film, preferably 3 parts by mass or more of 100. It is 5 parts by mass or more, more preferably 5 parts by mass or more and 100 parts by mass or less, and further 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 heat resistance of the optical laminate. It is 10 parts by mass or more and 50 parts by mass or less.

If the content of the compound (D) is excessively small, it is difficult to obtain the effect of increasing the heat resistance of the optical laminate by containing the compound (D). Further, when the content of the compound (D) is excessively small, the effect of enhancing the adhesion between the optical film and the first cured product layer in the optical laminate by containing the compound (D) and the first curing It is difficult to obtain the effect of increasing the adhesion between the material layer and the first thermoplastic resin film.

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

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

Other components include curable components and cross-linking agents such as polyhydric aldehydes, melamine compounds, zirconia compounds, zinc compounds, aziridine compounds, glioxal, glioxal derivatives, and water-soluble epoxy resins; other than carboxyl group-modified polyvinyl alcohol-based polymers. Modified polyvinyl alcohol-based polymer; Additives such as coupling agent, tackifier, antioxidant, ultraviolet absorber, heat stabilizer, hydrolysis inhibitor and the like can be mentioned.

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

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

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

The curable composition (S) can be used as a coating liquid for forming a coating film (coating layer) on the substrate. For example, a coating film can be formed by applying the curable composition (S) onto a substrate and curing the coating layer. The base material is preferably an optical film. The optical film will be described later. In this case, the optical laminate includes an optical film and a first cured product layer composed of a cured product 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 adhering an optical film and a first thermoplastic resin film. In this case, the optical laminate includes an optical film, a first cured product layer (adhesive layer) composed of a cured product of the curable composition (S), and a first thermoplastic resin film in this order. In this optical laminate, the curable composition (S) is coated on at least one of the bonding surfaces of the optical film and the first thermoplastic resin film, and the optical film and the first thermoplastic are coated through the coating layer. It can be produced by laminating a resin film to obtain a laminated body and then curing the coating layer.

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

The curable composition (S), which is an adhesive composition, is preferably an adhesive composition for a 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 an aqueous composition. That is, the curable composition (S) is preferably a solution in which the compounding component is dissolved in a solvent containing water, or a dispersion (for example, an emulsion) in which the compounding component is dispersed in a solvent containing water.

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

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

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

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

[1] Configuration of Optical Laminates FIGS. 1 to 5 show examples of layer configurations of the optical laminates.

The optical laminate shown in FIG. 1 includes an optical film 30 and a first cured product layer 15 laminated on one surface of the optical film 30. The first cured product layer 15 can function as an overcoat layer that coats and protects the surface of the optical film 30, an optical functional 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 product 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 via a first cured product layer 15. The first cured product layer 15 can function as an adhesive layer for adhering the optical film 30 and the first thermoplastic resin film 10.

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

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

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

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

It is preferable that the optical film 30 and the second cured product layer 25 are in direct contact with each other.
The optical laminate shown in FIG. 4 is laminated and attached to the optical film 30, the first cured product layer 15 laminated on one surface thereof, and the other surface of the optical film 30 via the second cured product layer 25. Includes a second thermoplastic resin film 20 to be combined. The first cured product layer 15 can function as an overcoat layer that coats and protects the surface of the optical film 30, an optical functional layer that additionally imparts an optical function to the optical film 30, and the like. The second cured product layer 25 can function as an adhesive layer for adhering the optical film 30 and the second thermoplastic resin film 20.

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

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

The optical film 30 may be various optical films (films having optical characteristics) that can be incorporated into 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 improving film, an antiglare film, an antireflection film, a diffusion film, a light collecting film and the like.

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

[2] Polarized light The polarized light is a layer or film having a function of selectively transmitting linearly polarized light in a certain direction from natural light.

Examples of the polarizer include a film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film. Examples of the dichroic dye include iodine and a dichroic organic dye.

Further, the polarizing element may be a coating type polarizing film in which a dichroic dye in a Riotrovic liquid crystal state is coated on a base film and oriented and immobilized.

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

The polarizer is not limited to the absorption type polarizer, but is a reflection type polarizer that selectively transmits linearly polarized light in one direction from natural light and reflects the linearly polarized light in the other direction, or a linearly polarized light in the other direction. A scattering type polarizer may be used, but an absorption type polarizer is preferable from the viewpoint of excellent visibility. Of these, a polyvinyl alcohol-based polarizing film composed of a polyvinyl alcohol-based resin film is more preferable, and a polyvinyl alcohol-based polarizing film in which a bicolor dye such as iodine or a bicolor dye is adsorbed and oriented on the polyvinyl alcohol-based resin film is preferable. More preferably, a polyvinyl alcohol-based polarizing film in which iodine is adsorbed and oriented on the polyvinyl alcohol-based resin film is particularly preferable.

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

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

The average degree of polymerization of the polyvinyl alcohol-based resin can be determined in accordance with JIS K 6726: 1994.

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

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

The thickness of the polarizer can be 40 μm or less, preferably 30 μm or less (for example, 20 μm or less, further 15 μm or less, and further 10 μm or less or 8 μm or less). According to the methods described in JP-A-2000-338329 and JP-A-2012-159778, 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, further 15 μm. Below, it becomes easier to make it 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 reducing the thickness of the optical laminate (polarizing plate) and the image display device including the optical laminate (polarizing plate).

[3] Phase-difference film The retardation film is a stretched film obtained by uniaxially stretching or biaxially stretching a translucent thermoplastic resin; a film in which a liquid crystal compound such as a discotic liquid crystal or a nematic liquid crystal is oriented and fixed; Examples thereof include those in which the above-mentioned liquid crystal layer is formed on a material film. Further, in the present specification, the 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 cellulosic ester resin such as triacetyl cellulose.

Examples of the translucent thermoplastic resin include resins constituting the first thermoplastic resin film 10 described later.

The zero Letters retardation film in-plane retardation value _{R e} and the thickness direction retardation _{R th} means a film are both -15～15Nm. This retardation film is suitably used for a liquid crystal display device in IPS mode. Plane retardation value _{R e} and the thickness direction retardation _{R th} are preferably both -10～10Nm, more preferably both -5～5Nm. The in-plane retardation value _Re and the thickness direction retardation value R _th referred to here are values at a wavelength of 590 nm.

The in-plane retardation value Re and the thickness direction retardation value Rth are expressed by the following equations, respectively:
_Re = (n _{x −} n _y ) × d
R _th = [(n _x + n _y ) /2- _nz ] × d
Defined in. Wherein, n _x is a refractive index in a slow axis direction (x-axis direction) in the film plane, n _y is the fast axis direction in the film plane of the (y-axis direction orthogonal to the x-axis in a plane) It is the refractive index, _nz is the refractive index in the film thickness direction (the z-axis direction perpendicular to the film surface), and d is the film thickness.

As the zero retardation film, for example, a resin film made of a polyolefin resin such as a cellulose resin, a chain polyolefin resin and a cyclic polyolefin resin, a polyethylene terephthalate resin or a (meth) acrylic resin can be used. In particular, since the retardation value can be easily controlled and easily obtained, a cellulosic resin, a polyolefin resin or a (meth) acrylic resin is preferably used.

As a film that expresses optical anisotropy by coating and orientation of a liquid crystal compound,
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 the rod-shaped liquid crystal compound is oriented perpendicular to the supporting substrate,
Third form: A retardation film in which the rod-shaped liquid crystal compound changes its orientation spirally in the plane.
Fourth form: a retardation film in which a disk-shaped liquid crystal compound is inclined or oriented,
Fifth form: A biaxial retardation film in which a disk-shaped liquid crystal compound is oriented perpendicularly to a supporting substrate.

For example, as the optical film used for the 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 made of a polymer in the oriented state of the polymerizable liquid crystal compound (hereinafter, may be referred to as an "optical anisotropic layer"), the retardation film may have anti-wavelength dispersibility. preferable. The inverse wavelength dispersibility is an optical characteristic in which the in-plane retardation value of the liquid crystal alignment at a short wavelength is smaller than the in-plane retardation value of the liquid crystal alignment at a long wavelength. (1) and equation (2) are satisfied. Incidentally, R e _(λ) represents an in-plane retardation value for light at a wavelength of [lambda] nm.

_Re (450) / _Re (550) ≤ 1 (1)
1 ≦ _Re (630) / _Re (550) (2)
When the phase difference film has a a and reverse wavelength dispersion first form, preferably for reducing the black state of coloration of the display device, 0.82 ≦ R _{e (450)} In the formula (1) / R _e It is more preferable if (550) ≦ 0.93. Further, 120 ≦ _Re (550) ≦ 150 is preferable.

When the retardation film is a film having an optically anisotropic layer, the polymerizable liquid crystal compound is described in "3" of the Liquid Crystal Handbook (edited by the Liquid Crystal Handbook Editorial Committee, published on October 30, 2000 by Maruzen Co., Ltd.). Among the compounds described in ".8.6 Network (completely crosslinked type)" and "6.5.1 Liquid crystal material b. Polymerizable nematic liquid crystal material", compounds having a polymerizable group, and Japanese Patent Application Laid-Open No. 2010-31223 Japanese Patent Application Laid-Open No. 2010-270108, Japanese Patent Application Laid-Open No. 2011-6360, Japanese Patent Application Laid-Open No. 2011-207765, Japanese Patent Application Laid-Open No. 2016-81035, International Publication No. 2017/043438 and Japanese Patent Application Laid-Open No. 2011-207765 The polymerizable liquid crystal compound described in the above can be mentioned.

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

In the second embodiment, the in-plane retardation value _R e (550) is in the range of 0 to 10 nm, preferably may be adjusted in the range of 0 to 5 nm, a thickness 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 phase difference value R _th in the thickness direction, which means the refractive index anisotropy in the thickness direction, is the phase difference value R ₅₀ and the in-plane phase difference value measured by inclining 50 degrees with the in-plane phase advance axis as the inclination axis. It can be calculated from the 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 inclining the phase advance axis by 50 degrees with the phase advance axis as the tilt axis, the thickness d of the retardation film, and the position. From the average refractive index n ₀ of the retardation film, n _x , _ny and n _z can be obtained by the following equations (4) to (6), and these can be substituted into the equation (3) for calculation.

R _th = [(n _x + _ny ) /2- _nz ] x d (3)
_Re = (n _{x −} n _y ) × d (4)
R ₅₀ = (n _{x −} n _y ') × d / cos (φ) (5)
(N _x + n _y + n _z ) / 3 = n ₀ (6)
here,
φ = sin ^-1 [sin (40 °) / n ₀ ]
n _y '= n _y x n _z / [ _ny ² x sin ² (φ) + n _z ² x cos ² (φ)] ^1/2
The retardation film may be a multilayer film having two or more layers. For example, a protective film is laminated on one side or both sides of a retardation film, and two or more retardation films are laminated via an adhesive or an adhesive.

[4] First Cured Product Layer The first cured product layer 15 is a cured product layer composed of a cured product 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, for example, a chain polyolefin resin. Polyethylene resin such as (polypropylene resin, etc.), cyclic polyolefin resin (norbornen resin, etc.); Cellulosic ester resin such as triacetyl cellulose, diacetyl cellulose; polyester terephthalate, polyethylene naphthalate, thermoplastic terephthalate, etc. A film made of a resin; a polycarbonate resin; a (meth) acrylic resin; a polystyrene resin; or a mixture thereof, a copolymer, or the like can be used.

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

The first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 may be a protective film that plays a role of protecting the optical film 30, or is a protective film that also has an optical function such as a retardation film. You can also do it.

For the retardation film, the description in [4] above is cited.
Examples of the chain polyolefin resin include homopolymers of chain olefins such as polyethylene resin and polypropylene resin, and copolymers composed of two or more kinds of chain olefins.

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

Of these, a norbornene-based resin using a norbornene-based monomer such as norbornene or a polycyclic norbornene-based monomer is preferably used as the cyclic olefin.

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

Examples of the acetyl cellulosic resin include triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate.

The polyester-based resin is a resin other than the above-mentioned cellulose ester-based resin having an ester bond, and is generally composed of a polyvalent carboxylic acid or a polycondensate of a derivative thereof and a polyhydric alcohol.

Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethylterephthalate, and polycyclohexanedimethylnaphthalate.

Of these, polyethylene terephthalate is preferably used from the viewpoints of mechanical properties, solvent resistance, scratch resistance, cost and the like. Polyethylene terephthalate refers to a resin in which 80 mol% or more of the repeating unit is composed of ethylene terephthalate, and is a constituent unit derived from other copolymerization components (dicarboxylic acid component such as isophthalic acid; diol component such as propylene glycol). May include.

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

As the polycarbonate, 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 thereof include polycarbonate derived from bisphenols such as 1-bis (4-hydroxyphenyl) isobutane and 1,1-bis (4-hydroxyphenyl) ethane.

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

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

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

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

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

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

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

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

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

The cyclic acid anhydride structure and the cyclic imide structure are introduced by copolymerizing a monomer having a cyclic structure such as maleic anhydride and maleimide; the cyclic acid anhydride structure is formed by a dehydration / demethanol condensation reaction after polymerization. Method of introduction; It can be introduced by a method of reacting an amino compound to introduce a cyclic imide structure or the like.

For a resin (polymer) having a lactone ring structure, after preparing a polymer having a hydroxyl group and an ester group in a polymer chain, the hydroxyl group and the ester group in the obtained polymer are required by heating. Therefore, it can be obtained by a method of forming a lactone ring structure by cyclization condensation in the presence of a catalyst such as an organic phosphorus compound.

The (meth) acrylic resin and the thermoplastic resin film formed from the (meth) acrylic resin may contain additives, if necessary. Examples of the additive include a lubricant, an antiblocking agent, a heat stabilizer, an antioxidant, an antistatic agent, a lightproofing agent, an impact resistance improving agent, a surfactant and the like.

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

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

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

Examples of the alkyl acrylate that is the main component of the elastic polymer include methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, and the like, which have an alkyl group having 1 or more and 8 or less carbon atoms. An alkyl acrylate having an alkyl group having 4 or more carbon atoms is preferably used.

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

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

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

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

The first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 contains an ultraviolet absorber, an infrared absorber, an organic dye, a pigment, an inorganic dye, an antioxidant, an antioxidant, a surfactant, a lubricant, and the like. It may contain a dispersant, a heat stabilizer and the like. When the optical laminate is applied to an image display device, the image display element is provided by arranging a thermoplastic resin film containing an ultraviolet absorber on the visible side of the image display element (for example, a liquid crystal cell or an organic EL display element). Deterioration due to ultraviolet rays can be suppressed.

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

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

The first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 has a hard coat layer, an antiglare layer, an antireflection layer, a light diffusion layer, and an antistatic layer on the 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.

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

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

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

[6] Second Curable Layer The curable composition forming the second cured layer 25 may be the above-mentioned curable composition (S), or may be another curable composition different from this. There may be. The second cured product layer 25 is preferably a cured product layer of the curable composition (S) from the viewpoint of heat resistance of the optical laminate.

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

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 an active energy ray-curable compound. Examples thereof include a curable composition (including an active energy ray-curable adhesive).

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

The aqueous composition containing a polyvinyl alcohol-based resin is a curable component such as a polyhydric aldehyde, a melamine-based compound, a zirconia compound, a zinc compound, a glyoxal, a glyoxal derivative, and a water-soluble epoxy resin in order to improve adhesion and adhesiveness. And a cross-linking agent can be further contained.

Examples of the aqueous composition containing a urethane resin include an aqueous composition containing a polyester ionomer type urethane resin and a compound having a glycidyloxy group. The polyester-based ionomer type urethane resin is a urethane resin having a polyester skeleton, in which a small amount of an ionic component (hydrophilic component) is introduced.

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

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

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

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

When the active energy ray-curable composition contains an epoxy-based compound that is cured by cationic polymerization as a curable component, it preferably contains a photocationic polymerization initiator. Examples of the photocationic polymerization initiator include aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic sulfonium salts; and iron-allene complexes.

When the active energy ray-curable composition contains a radically polymerizable component such as a (meth) acrylic compound, it preferably contains a photoradical polymerization initiator. Examples of the photoradical polymerization initiator include an acetophenone-based initiator, a benzophenone-based initiator, a benzoin ether-based initiator, a thioxanthone-based initiator, xanthone, fluorenone, camphorquinone, benzaldehyde, anthraquinone and the like.

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

[7] Manufacture of Optical Laminate The optical laminate having the configuration shown in FIG. 2 is obtained by laminating and adhering the first thermoplastic resin film 10 to one surface of the optical film 30 via the first cured product layer 15. It can be obtained, and by further laminating and adhering the second thermoplastic resin film 20 to the other surface of the optical film 30 via the second cured product layer 25, an optical laminate having the configuration shown in FIG. 3 can be obtained. Can be done.

When producing 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 one side at a time step by step, or the films on both sides may be laminated and bonded at the same time. It may be laminated and bonded.

As a method of adhering the optical film 30 and the first thermoplastic resin film 10, the curable composition (S) is applied to one or both of the bonding surfaces of the optical film 30 and the first thermoplastic resin film 10. Examples thereof include a method of coating, laminating the other laminating surface on the laminating surface, and pressing from above and below using a laminating roll or the like for laminating.

For coating the curable composition (S), various coating methods such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater can be used. Further, even if the optical film 30 and the first thermoplastic resin film 10 are continuously supplied so that the bonding surfaces of both are on the inside, the curable composition (S) is cast between them. Good.

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

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

When an active energy ray-curable composition is used as the curable composition constituting the second cured product layer, the curable composition layer is dried as necessary and then irradiated with active energy rays to form the curable composition. Harden the material layer.

The light source used for irradiating the active energy beam may be any light source capable of generating ultraviolet rays, electron beams, X-rays and the like. In particular, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, and the like having an emission distribution having a wavelength of 400 nm or less are preferably used.

As shown in FIG. 1, an optical laminate having no first thermoplastic resin film on the first cured product layer 15 was obtained by applying the curable composition (S) on the surface of the optical film 30. The laminate can be produced, for example, by subjecting the laminate to heat treatment at 80 ° C. for 300 seconds with a hot air dryer. Further, the optical laminate shown in FIG. 1 is also produced by producing a laminate composed of a separate film / curable composition (S) / optical film 30, peeling off the separate film, and then performing 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 further preferably. Is 20 nm or more and 1 μm or less. The cured product layer formed from the above-mentioned known aqueous composition can also have the same 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, and more preferably 500 nm or more and 5 μm or less.

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

[8] Other Components of Optical Laminate [8-1] Optical Functional Film The optical laminate has optical functionality other than the optical film 30 (for example, a polarizer) for imparting a desired optical function. A film can be provided, a preferred example thereof being 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 product layer 15 and / or the second cured product layer 25 via the adhesive layer and the adhesive layer. Can be laminated on the outer surface of. For the retardation film, the description in [4] above is cited.

Examples of other optical functional films (optical members) that can be included in an optical laminate such as a polarizing plate include a condenser plate, a brightness improving film, a reflective layer (reflective film), a semi-transmissive reflective layer (semi-transmissive reflective film), and the like. A light diffusing layer (light diffusing film) or the like.

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

The brightness improving film is used for the purpose of improving the brightness in an image display device to which an optical laminate such as a polarizing plate is applied. Specifically, a reflective polarizing separation sheet designed to generate anisotropy in reflectance by laminating a plurality of thin films having different anisotropy in refractive index, an alignment film of cholesteric liquid crystal polymer, and its orientation. Examples thereof include a circularly polarized light separation sheet in which a liquid crystal layer is supported on a base film.

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

[8-2] Adhesive Layer The optical laminate can include an adhesive layer. Examples of the pressure-sensitive adhesive layer include a pressure-sensitive adhesive layer for bonding an 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 configuration shown in FIGS. 1 and 2, and the first thermoplastic resin film 10 or the second thermoplastic in the optical laminate having the configuration shown in FIG. The outer surface of the resin film 20, the outer surface of the first cured product 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 product layer 25.

FIG. 6 shows an example in which the pressure-sensitive adhesive layer 40 is laminated on the outer surface of the second thermoplastic resin film 20 of the optical laminate having the configuration shown in FIG.

As the pressure-sensitive adhesive used for the pressure-sensitive adhesive layer, a (meth) acrylic resin, a silicone-based resin, a polyester-based resin, a polyurethane-based resin, a polyether-based resin, or the like as a base polymer can be used. Among them, a (meth) acrylic pressure-sensitive adhesive is preferable from the viewpoints of transparency, adhesive strength, reliability, weather resistance, heat resistance, reworkability and the like.

The (meth) acrylic pressure-sensitive adhesive includes a (meth) acrylic acid alkyl ester having an alkyl group having 20 or less carbon atoms such as a methyl group, an ethyl group, an n-, i- or t-butyl group, and (meth). A weight average molecular weight of a functional group-containing (meth) acrylic monomer such as acrylic acid or hydroxyethyl (meth) acrylic acid blended so that the glass transition temperature is preferably 25 ° C. or lower, more preferably 0 ° C. or lower. A (meth) acrylic resin having a value of 100,000 or more is useful as a base polymer.

For the formation of the pressure-sensitive adhesive layer on the optical laminate, for example, the pressure-sensitive adhesive composition is dissolved or dispersed in an organic solvent such as toluene or ethyl acetate to prepare a pressure-sensitive adhesive liquid, which is directly applied to the target surface of the optical laminate. A method of forming an adhesive layer by coating, a method of forming an adhesive layer in a sheet shape on a separate film that has been subjected to a mold release treatment, and a method of transferring it to a target surface of an optical laminate, etc. Can be done by

The thickness of the pressure-sensitive adhesive layer is determined according to the adhesive strength and the like, but a range of 1 μm or more and 50 μm or less is appropriate, and preferably 2 μm or more and 40 μm or less.

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

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

[8-3] Protect film The surface of the optical laminate (typically, the first thermoplastic resin film 10, the second thermoplastic resin film 20, the first cured product layer 15 and / or the second cured product layer) A protective film for protecting the surface of 25) can be included. After the optical laminate is attached to, for example, an image display element or another optical member, the protective film is peeled off and removed together with the adhesive layer contained therein.

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

The resin constituting the base film is, for example, a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate or polyethylene naphthalate, or a thermoplastic resin such as a polycarbonate resin. be able to. A polyester resin such as polyethylene terephthalate is preferable.

<Image display device>
The optical laminate according to the present invention can be applied to an image display device. In this case, the image display device includes an optical laminate and an image display element. Examples of the image display element include a liquid crystal cell and an organic EL display element. As these image display elements, conventionally known ones can be used.

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

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these examples. In the examples,% and parts representing the content or the amount used are based on mass unless otherwise specified.

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

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

<Examples 1 to 5, Comparative Example 1>
(1) Preparation of curable composition A curable composition (adhesive aqueous solution) was prepared by mixing the components shown in Table 1 with pure water as a solvent in the blending amounts shown in Table 1. The unit of the blending amount of each component shown in Table 1 is a mass part, and the blending amount of each component is the amount in terms of solid content. In Examples 1 and 2, the concentration of (A) in the obtained curable composition was 7.0% by mass, and the concentration of (A) in the curable composition of Example 3 was 6.0% by mass. The concentration of (A) in the curable composition of Example 4 was 5.0% by mass, and the concentration of (A) in the curable composition of Example 5 was 4.0% by mass. In Comparative Example 1, the concentration of (X) in the curable composition was 3.0% by mass.

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

(3) Evaluation of optical durability (heat resistance) (3-1) Measurement of ΔTy rate of change After cutting the obtained polarizing plate into a size of 30 mm × 30 mm, a (meth) acrylic system is placed on the zero retardation film side. It was attached to a glass substrate via an adhesive to obtain a measurement sample. The layer structure of the measurement sample is a glass substrate / (meth) acrylic pressure-sensitive adhesive layer / zero retardation film / cured product layer / polarizer / cured product layer / TAC film. As the glass substrate, a non-alkali glass substrate [trade name "Eagle XG" manufactured by Corning Inc.] was used.

For the obtained measurement sample, MD transmittance and TD transmittance in the wavelength range of 380 to 780 nm were measured using a spectrophotometer with an integrating sphere [product name "V7100" manufactured by JASCO Corporation], and each wavelength was measured. The single transmittance in was calculated. The calculated single transmittance was corrected for luminosity factor using the two-degree field (C light source) of JIS Z 8701: 1999 "Color display method-XYZ color system and X ₁₀ Y ₁₀ Z ₁₀ color system", and a heat resistance test was performed. The previous visibility correction single transmittance Ty was obtained. The measurement sample was set in a spectrophotometer with an integrating sphere so that the TAC film side of the polarizing plate was the detector side and the light entered from the glass substrate side.

The single transmittance (%) is calculated by the following formula:
Single transmittance (λ) = (Tp (λ) + Tc (λ)) / 2
Defined in.

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

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

Next, this measurement sample was placed in a dry environment at a temperature of 105 ° C. for 750 hours and then subjected to a heat resistance test in which the measurement sample was placed in an environment with a temperature of 23 ° C. and a relative humidity of 50% RH for 24 hours. After the heat resistance test, the luminosity factor correction single transmittance Ty was determined by the same method as before the heat resistance test.

The absolute value (| ΔTy |) of the difference between the luminosity factor corrected single transmittance Ty after the heat resistance test and the luminosity factor corrected single transmittance Ty before the heat resistance test was calculated.

Next, from the obtained values of | ΔTy |, the “ΔTy change rate” (%) of each example based on | ΔTy | of Comparative Example 1 was obtained based on the following formula. The calculated values of the rate of change of ΔTy are shown in Table 1. The larger the rate of change of ΔTy, the better the heat resistance.

ΔTy change rate (%) of each example
= | {(| ΔTy | in each example)-(| ΔTy | in Comparative Example 1)} | / (| ΔTy | in Comparative Example 1)
In each of the examples and comparative examples, ΔTy showed a negative value.

(3-2) Measurement of Δab change rate After cutting the obtained polarizing plate into a size of 30 mm × 30 mm, the polarizing plate was attached to a glass substrate via a (meth) acrylic adhesive on the zero retardation film side. A measurement sample was obtained. The layer structure of the measurement sample is a glass substrate / (meth) acrylic pressure-sensitive adhesive layer / zero retardation film / cured product layer / polarizer / cured product layer / TAC film. As the glass substrate, a non-alkali glass substrate [trade name "Eagle XG" manufactured by Corning Inc.] was used.

For the obtained measurement sample, MD transmittance and TD transmittance in the wavelength range of 380 to 780 nm were measured using a spectrophotometer with an integrating sphere [product name "V7100" manufactured by JASCO Corporation], and each wavelength was measured. The single transmittance in was calculated. Using the calculated single transmission rate, the a value and b value of the transmitted hue were calculated based on the Lab display system defined by the CIE (International Lighting Committee).

Next, this measurement sample was placed in a dry environment at a temperature of 105 ° C. for 750 hours and then subjected to a heat resistance test in which the measurement sample was placed in an environment with a temperature of 23 ° C. and a relative humidity of 50% RH for 24 hours. After the heat resistance test, the a value and b value of the transmitted hue were determined by the same method as before the heat resistance test. Using the measured a and b values before and after durability, the absolute value (| Δab |) of the Δab value, which is an index of the hue change by the heat resistance test, was calculated from the following formula.

| Δab | = | {(a (after endurance test) -a (before endurance test)) ² + (b (after endurance test) -b (before endurance test)) ² } ^1/2 |
Next, from the obtained values of | Δab |, the "Δab change rate" (%) of each example based on | Δab | of Comparative Example 1 was obtained based on the following formula. The calculated values of the rate of change of Δab are shown in Table 1. The larger the rate of change of Δab, the better the heat resistance.

Δab change rate (%) of each example
= 100 × | {(| Δab | in each example)-(| Δab | in Comparative Example 1)} | / (| Δab | in Comparative Example 1)
In each of the examples and comparative examples, Δab showed a positive value.

Details of each component shown in Table 1 are as follows.
a1: Trade name "Epocross WS-300" manufactured by Nippon Catalyst Co., Ltd. [2-Aqueous solution of oxazoline group-containing acrylic polymer having an oxazoline group as a side chain, solid content concentration: 10% by mass, oxazoline value (theoretical value) : 130 g solid / eq. , Oxazoline group weight (theoretical value): 7.7 mmol / g, solid, number average molecular weight: 4 × 10 ⁴ , weight average molecular weight: 12 × 10 ⁴ )]
b1: Zinc chloride (ZnCl ₂ )
b2: Zinc iodide (ZnI ₂ )
c1: Citric acid d1: Sulfuric acid x1: Product name "Gosefimer Z-200" manufactured by Nippon Synthetic Chemical Industry Co., Ltd. [Acetyl group-modified polyvinyl alcohol, average degree of polymerization: 1100, degree of saponification: 98.5 mol% that's all〕
y1: Glyoxal

10 1st thermoplastic resin film, 15 1st cured product layer, 20 2nd thermoplastic resin film, 25 2nd cured product layer, 30 optical film, 40 adhesive layer.

Claims (8)

Oxazoline group-containing polymer (A) and
Zinc compound (B) and
A curable composition comprising at least one selected from the group consisting of compound (C) having a carboxyl group and an acid anhydride of compound (C). The curable composition according to claim 1, further comprising a compound (D) that promotes 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. An optical laminate comprising an optical film and a first cured product layer composed of a cured product of the curable composition according to claim 1 or 2. The optical laminate according to claim 3, further comprising the optical film, the first cured product layer, and the first thermoplastic resin film in this order. The optical laminate according to claim 4, further comprising a second thermoplastic resin film, a second cured product layer, the optical film, the first cured product layer, and the first thermoplastic resin film in this order. .. The optical laminate according to any one of claims 3 to 5, wherein the optical film is a polarizer. An image display device including the optical laminate according to any one of claims 3 to 6 and an image display element. An adhesive composition for a polarizing plate containing an oxazoline group-containing polymer (A) and a zinc compound (B).

Images