Curable composition, cured product layer, optical laminate, and image display device

Abstract

To provide a curable composition capable of imparting an optical laminate including a cured product layer composed of a cured product of the curable composition, the optical laminate excellent in optical durability under a high-temperature high-humidity environment.SOLUTION: A curable composition at least includes an aqueous resin and a silane compound having a silanol group. The aqueous resin includes an oxazolyl group-including (meth)acrylic resin having an oxazolyl group in a molecule. The silane compound includes one or more functional groups selected from a group consisting an amino group, a carboxyl group, an epoxy group, an acetoacetyl group, a hydroxyalkyl group, a mercapto group, an oxyalkylene group, and an alkenyl group, which may include a substituent group, and the silane compound further includes a Si-O-Si bond. The curable composition further includes an acid compound.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a curable composition. The present invention also relates to a cured product layer formed from a cured product of the curable composition, an optical laminate including the cured product layer, and an image display device including the optical laminate. [Background technology]

[0002] In recent years, LCD devices have been deployed in mobile devices such as smartphones and tablet PCs, and in-vehicle devices such as car navigation systems. These applications may be exposed to harsher environments than traditional indoor TV applications, making improving the durability of the devices a challenge.

[0003] Similarly, durability is required for optical films constituting liquid crystal display devices, etc. That is, optical films incorporated into liquid crystal display devices, etc. may be placed in high temperature or high temperature and high humidity environments, or in environments where high temperature and low temperature are alternately changed, and it is required that the optical properties do not deteriorate even in these environments.

[0004] Examples of optical films include polarizing plates in which a protective film is attached to one or both sides of a polarizer using an adhesive (Patent Document 1, etc.). [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2017-82026 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a curable composition that can provide an optical layer that includes a cured product layer formed from the cured product of the curable composition and has good optical durability under high-temperature and high-humidity environments. Another object of the present invention is to provide an optical laminate that includes a cured product layer formed from a cured product of a curable composition and has good optical durability under high-temperature and high-humidity environments, and an image display device that includes the same. [Means for solving the problem]

[0007] The present invention provides the following curable composition, cured product layer, optical laminate, and image display device. [1] A curable composition comprising at least an aqueous resin and a silane compound having a silanol group. [2] The curable composition according to [1], wherein the silane compound further has one or more functional groups selected from the group consisting of an amino group, a carboxyl group, an epoxy group, an acetoacetyl group, a hydroxyalkyl group, a mercapto group, an oxyalkylene group, and an alkenyl group, each of which may have a substituent. [3] The curable composition according to [1] or [2], wherein the silane compound further has at least one functional group selected from an amino group and a carboxyl group, each of which may have a substituent. [4] The silane compound further contains a Si—O—Si bond, The curable composition according to [2] or [3], wherein the functional group is contained in the structure of the silane compound. [5] The curable composition according to any one of [1] to [4], wherein the aqueous resin contains at least one of a hydroxyl group-containing resin and a (meth)acrylic resin. [6] The curable composition according to [5], wherein the hydroxyl group-containing resin includes at least one of a polyvinyl alcohol-based resin and a polyvinyl acetal-based resin. [7] A cured product layer obtained by curing the curable composition according to any one of [1] to [6]. [8] An optical layer and a first cured product layer, The first cured product layer is the cured product layer according to [7]. [9] Further, a first thermoplastic resin film is included, [8] The optical laminate according to [8], wherein the optical layer, the first cured product layer, and the first thermoplastic resin film are laminated in this order.

[10] Further comprising a second cured product layer and a second thermoplastic resin film, The optical laminate according to [8] or [9], wherein the second cured material layer and the second thermoplastic resin film are laminated in this order on the side of the optical layer opposite to the first cured material layer side.

[11] The optical laminate according to

[10] , wherein the second cured material layer is the cured material layer according to [7].

[12] The optical laminate according to any one of [8] to

[11] , wherein the optical layer is a polarizer.

[13] An image display device comprising the optical laminate according to any one of [8] to

[12] and an image display element. [Effects of the Invention]

[0008] A curable composition can be provided that can give an optical layered product that includes a cured product layer formed from the cured product of the curable composition and has good optical durability in a high-temperature, high-humidity environment. It is possible to provide an optical laminate that includes a cured product layer formed from a cured product of a curable composition and has good optical durability under high-temperature and high-humidity environments, and an image display device that includes the same. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic cross-sectional view showing an example of an optical laminate according to the present invention. [Figure 2] FIG. 2 is a schematic cross-sectional view showing another example of the layer structure of the optical laminate according to the present invention. [Figure 3] FIG. 2 is a schematic cross-sectional view showing another example of the layer structure of the optical laminate according to the present invention. [Figure 4] FIG. 2 is a schematic cross-sectional view showing another example of the layer structure of the optical laminate according to the present invention. [Figure 5] FIG. 2 is a schematic cross-sectional view showing another example of the layer structure of the optical laminate according to the present invention. [Figure 6]FIG. 2 is a schematic cross-sectional view showing another example of the layer structure of the optical laminate according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Curable composition> The curable composition according to the present invention contains at least an aqueous resin and a silane compound having a silanol group. Hereinafter, the curable composition according to the present invention will be referred to as the "curable composition (S)," the aqueous resin as the "aqueous resin (A)," and the silane compound having a silanol group as the "silane compound (B)."

[0011] The curable composition (S) can be used as a coating liquid for forming a coating film (coating layer) on a substrate. For example, the curable composition (S) can be applied to a substrate and the coating layer cured to form a coating film. The substrate is preferably an optical layer. The optical layer will be described later. In this case, the optical laminate includes an optical layer and a first cured product layer composed of a cured product of the curable composition (S).

[0012] The curable composition (S) can also be used as an adhesive composition. In one embodiment, the curable composition (S) is an adhesive composition for bonding an optical layer and a first thermoplastic resin film. In this case, the optical laminate includes, in this order, an optical layer, a first cured product layer (adhesive layer) composed of a cured product of the curable composition (S), and a first thermoplastic resin film. This optical laminate can be produced by coating the curable composition (S) on the bonding surface of at least one of the optical layer and the first thermoplastic resin film, laminating the optical layer and the first thermoplastic resin film via the coating layer to obtain a laminate, and then curing the coating layer.

[0013] The curable composition (S) is an aqueous composition containing an aqueous resin (A). The aqueous composition is a solution in which the ingredients are dissolved in a solvent containing water, or a dispersion (e.g., emulsion) in which the ingredients are dispersed in a solvent containing water.

[0014] The viscosity of the curable composition (S) at 25°C is preferably 50 mPa·sec or less, more preferably 1 mPa·sec or more and 30 mPa·sec or less, and even more preferably 2 mPa·sec or more and 20 mPa·sec or less. If the viscosity at 25°C exceeds 50 mPa·sec, it may become difficult to apply the composition uniformly, resulting in uneven coating, and problems such as clogged pipes may occur. The viscosity of the curable composition (S) at 25° C. can be measured with an E-type viscometer.

[0015] [1] Water-based resin (A) The aqueous resin (A) contains at least one of a water-soluble resin soluble in an aqueous solvent and a water-dispersible resin dispersible in an aqueous solvent. In this specification, the term "aqueous solvent" refers to water or a solvent containing water as the main component, and "containing water as the main component" refers to a solvent containing water that accounts for 50% by mass or more of the total mass of the components constituting the solvent. The solvent other than water among the aqueous solvents is not particularly limited as long as it does not easily undergo phase separation in the presence of water, but a solvent that dissolves in water is preferred, and examples thereof include alcohols such as methanol, ethanol, isopropyl alcohol, and n-propyl alcohol; ketones such as acetone and methyl ethyl ketone; glycols such as ethylene glycol and diethylene glycol; and glycol ethers such as N-methylpyrrolidone (NMP), tetrahydrofuran, and butyl cellosolve.

[0016] The water-soluble resin is not particularly limited as long as it is soluble in an aqueous solvent. The water-dispersible resin is not particularly limited as long as it is dispersible in an aqueous solvent. Examples of water-soluble or water-dispersible resins include (meth)acrylic resins; polyvinyl alcohol resins; polyvinyl acetal resins; ethylene-vinyl alcohol copolymer resins; polyvinylpyrrolidone resins; polyamidoamine resins; epoxy resins; melamine resins; urea resins; polyamide resins; polyester resins; polyurethane resins; cellulose resins such as methyl cellulose, hydroethyl cellulose, and carboxymethyl cellulose; and polysaccharides such as sodium alginate and starch. Among these, (meth)acrylic resins and hydroxyl-containing resins such as polyvinyl alcohol resins and polyvinyl acetal resins are preferred, with (meth)acrylic resins, polyvinyl alcohol resins, and polyvinyl acetal resins being more preferred. In this specification, "(meth)acrylic" refers to at least one selected from the group consisting of acrylic and methacrylic. The same applies to expressions such as "(meth)acryloyl" and "(meth)acrylate".

[0017] The curable composition (S) may contain one or more of the above-mentioned aqueous resins (A). The content of the aqueous resin is preferably 30% by mass or more and 95% by mass or less, more preferably 35% by mass or more and 90% by mass or less, and even more preferably 40% by mass or more and 85% by mass or less, when the solid content concentration of the curable composition (S) is taken as 100% by mass. Setting the content of the aqueous resin within the above range is preferred from the viewpoints of improving the optical durability of the optical laminate in a high-temperature and high-humidity environment, and of improving the adhesion between the optical layer and the first cured product layer in the optical laminate, and between the first cured product layer and the first thermoplastic resin film. The solid content concentration refers to the total concentration of components other than the solvent contained in the curable composition (S).

[0018] [1-1] (Meth)acrylic resin A (meth)acrylic resin is a polymer or copolymer obtained by using a compound having one or more (meth)acryloyl groups in the molecule as the main monomer. The (meth)acrylic resin may be water-soluble or water-dispersible. The (meth)acrylic resin is a polymer or copolymer that contains, relative to 100% by mass of all structural units, preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more of structural units derived from a compound having one or more (meth)acryloyl groups in the molecule.

[0019] Examples of the compound having one or more (meth)acryloyl groups in the molecule include (meth)acrylates and (meth)acrylamides having at least one (meth)acryloyloxy group in the molecule. Furthermore, other monomers copolymerizable with a compound having one or more (meth)acryloyl groups in the molecule include compounds having one or more ethylenically unsaturated bonds in the molecule, such as vinyl compounds, typically styrene, styrene sulfonic acid, vinyl acetate, vinyl propionate, and N-vinyl-2-pyrrolidone.

[0020] The (meth)acrylic resin is preferably a (meth)acrylic resin having an oxazolyl group in the molecule (hereinafter, sometimes referred to as an "oxazolyl group-containing (meth)acrylic resin"), and more preferably a (meth)acrylic resin having an oxazolyl group in the side chain. By using an oxazolyl group-containing (meth)acrylic resin as the aqueous resin (A), it is easy to improve the optical durability of the optical laminate in a high-temperature, high-humidity environment, the adhesion between the optical layer and the first cured material layer in the optical laminate, and the adhesion between the first cured material layer and the first thermoplastic resin film.

[0021] The oxazolyl group-containing (meth)acrylic resin may be water-soluble or water-dispersible, but is preferably a water-soluble polymer from the viewpoint of the optical properties of the cured layer formed from the cured product of the curable composition (S).

[0022] The oxazolyl group-containing (meth)acrylic resin may contain a structural unit having an oxazolyl group on the side chain (a structural unit derived from an oxazolyl group-containing monomer) and a structural unit not having an oxazolyl group. A preferred example of the oxazolyl group-containing (meth)acrylic resin is one that contains a skeletal structure consisting of a (meth)acrylic skeleton as the main component of the structural unit, and has introduced as a copolymerization component a structural unit having an oxazolyl group in the side chain (a structural unit derived from an oxazolyl group-containing monomer). The oxazolyl group-containing (meth)acrylic resin may be one obtained by copolymerizing an oxazolyl group-containing monomer, or one obtained by modifying a side chain functional group of a polymer to contain an oxazolyl group.

[0023] Examples of the oxazolyl group include a 2-oxazolyl group, a 3-oxazolyl group, a 4-oxazolyl group, etc. The oxazolyl group is preferably a 2-oxazolyl group, etc. Examples of the oxazolyl group-containing monomer include 2-isopropenyl-2-oxazoline and vinyl-2-oxazoline.

[0024] The weight-average molecular weight of the oxazolyl group-containing (meth)acrylic resin is preferably at least 5000, more preferably at least 10000. A weight-average molecular weight within the above range can be advantageous from the viewpoints of improving the optical durability of the optical laminate in a high-temperature, high-humidity environment, and of improving the adhesion between the optical layer and the first cured product layer in the optical laminate, and between the first cured product layer and the first thermoplastic resin film. The weight average molecular weight of the oxazolyl group-containing (meth)acrylic resin is usually 1,000,000 or less. The weight average molecular weight of the oxazolyl group-containing (meth)acrylic resin can be measured as a value converted into standard polystyrene by gel permeation chromatography (GPC).

[0025] The amount of oxazolyl groups in the oxazolyl group-containing (meth)acrylic resin (the number of moles of oxazolyl groups per gram of solid content of the oxazolyl group-containing (meth)acrylic resin) is preferably 0.4 mmol / g solid or more. If the amount of oxazolyl groups is less than the above range, the optical durability of the optical laminate under high-temperature and high-humidity environments may be adversely affected. From this perspective, the amount of oxazolyl groups in the oxazolyl group-containing polymer is more preferably 3 mmol / g solid or more, and even more preferably 5 mmol / g solid or more and 9 mmol / g solid or less. There is no particular upper limit to the amount of oxazolyl groups, but it is usually 50 mmol / g solid or less.

[0026] Commercially available oxazolyl group-containing (meth)acrylic resins may be used. Specific examples include oxazolyl group-containing acrylic polymers such as EPOCROS WS-300, EPOCROS WS-500, and EPOCROS WS-700 (all trade names) manufactured by Nippon Shokubai Co., Ltd., and oxazolyl group-containing acrylic / styrene polymers such as EPOCROS K-1000 series, EPOCROS K-2000 series, and EPOCROS RPS series (all trade names) manufactured by Nippon Shokubai Co., Ltd. Two or more kinds of oxazolyl group-containing (meth)acrylic resins can be used in combination. From the viewpoints of the optical durability and optical properties of the optical laminate under high-temperature and high-humidity environments, the adhesion between the optical layer and the first cured material layer in the optical laminate, the adhesion between the first cured material layer and the first thermoplastic resin film, and the water resistance of the first cured material layer, the oxazolyl group-containing (meth)acrylic resin is preferably an oxazolyl group-containing acrylic polymer such as EPOCROS WS-300, EPOCROS WS-500, or EPOCROS WS-700.

[0027] [1-2] Polyvinyl alcohol resin By using a polyvinyl alcohol-based resin as the aqueous resin (A), it is easy to improve the optical durability of the optical laminate in a high-temperature, high-humidity environment, the adhesion between the optical layer 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.

[0028] Polyvinyl alcohol resins can be obtained by saponifying polyvinyl acetate resins. Examples of polyvinyl acetate resins include polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as copolymers of vinyl acetate with other monomers copolymerizable therewith. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, vinyl ethers, and acrylamides having an ammonium group. The polyvinyl alcohol resin used in the curable composition (S) preferably has an appropriate degree of polymerization. For example, when made into a 4 wt % aqueous solution, the viscosity thereof is preferably in the range of 4 to 50 mPa·sec, and more preferably in the range of 6 to 30 mPa·sec.

[0029] The degree of saponification of the polyvinyl alcohol-based resin is not particularly limited, but is generally preferably 70 mol% or more, and more preferably 80 mol% or more. If the degree of saponification of the polyvinyl alcohol-based resin is low, the water resistance of the cured material layer formed from the cured product of the curable composition (S), the adhesion between the optical layer and the first cured material layer in the optical laminate, and the adhesion between the first cured material layer and the first thermoplastic resin film tend to be insufficient.

[0030] The polyvinyl alcohol resin used in the curable composition (S) is preferably modified. Examples of such modified polyvinyl alcohol resins include acetoacetyl group-modified polyvinyl alcohol resins, carboxylic acid-modified polyvinyl alcohol resins, carbonyl group-modified polyvinyl alcohol resins, sulfonic acid-modified polyvinyl alcohol resins, hydrazide group-modified polyvinyl alcohol resins, thiol group-modified polyvinyl alcohol resins, alkyl group-modified polyvinyl alcohol resins, silyl group-modified polyvinyl alcohol resins, polyethylene glycol group-modified polyvinyl alcohol resins, ethylene oxide group-modified polyvinyl alcohol resins, polyvinyl alcohol resins modified with a group having a urethane bond, and phosphate ester group-modified polyvinyl alcohol resins. The use of such modified polyvinyl alcohol resins is preferred because it improves the water resistance of the cured product layer formed from the cured product of the curable composition (S), the adhesion between the optical layer 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.

[0031] The acetoacetyl-modified polyvinyl alcohol resin has an acetoacetyl group (CH3COCH2CO-) in addition to the hydroxyl group constituting the polyvinyl alcohol skeleton, and may also have other groups such as an acetyl group. The acetoacetyl group typically exists in a state where the hydrogen atom of the hydroxyl group is substituted. The acetoacetyl-modified polyvinyl alcohol resin can be produced, for example, by a method of reacting polyvinyl alcohol with diketene. The acetoacetyl-modified polyvinyl alcohol resin has an acetoacetyl group, which is a highly reactive functional group, and is therefore preferred for improving the durability of the cured layer formed from the cured product of the curable composition (S).

[0032] The content of acetoacetyl groups in the acetoacetyl-modified polyvinyl alcohol resin is not particularly limited as long as it is 0.1 mol% or more. The acetoacetyl group content here refers to the molar fraction of acetoacetyl groups relative to the total amount of hydroxyl groups, acetoacetyl groups, and other ester groups (such as acetyl groups) in the polyvinyl alcohol resin, expressed in %, and may be referred to as the "acetoacetylation degree" hereinafter. If the acetoacetylation degree of the polyvinyl alcohol resin is less than 0.1 mol%, the effect of improving the water resistance of the cured material layer formed from the cured product of the curable composition (S) is not necessarily sufficient. The acetoacetylation degree of the polyvinyl alcohol resin is preferably about 0.1 to 40 mol%, more preferably 1 to 20 mol%, and particularly preferably 2 to 7 mol%. If the acetoacetylation degree exceeds 40 mol%, the effect of improving water resistance is reduced.

[0033] The acetoacetyl group-modified polyvinyl alcohol resin may be a commercially available product, specifically, the "GOHSEFIMER Z" series available from Nippon Synthetic Chemical Industry Co., Ltd.

[0034] Carboxylic acid-modified polyvinyl alcohol resins have carboxyl groups (-COOH) in addition to the hydroxyl groups that make up the polyvinyl alcohol skeleton. Carboxylic acid-modified polyvinyl alcohol resins can be produced by copolymerizing an unsaturated monomer having a carboxyl group with vinyl acetate, followed by saponification. The carboxylic acid-modified polyvinyl alcohol resin may be a commercially available product, and specific examples thereof include "KL-318" and "KM-118" manufactured by Kuraray Co., Ltd., "Gohsenaal T-330" and "Gohsenaal T-215" manufactured by Mitsubishi Chemical Corporation, and the "A-Polymer" series manufactured by Nippon Vaccination & Poval Co., Ltd.

[0035] A carbonyl-modified polyvinyl alcohol resin is one that has a group containing a carbonyl group in addition to the hydroxyl groups that constitute the polyvinyl alcohol skeleton. The group containing a carbonyl group is not particularly limited as long as it is a group represented by -COR, and examples thereof include an amide group, an acyl group, and an aldehyde group. A carbonyl-modified polyvinyl alcohol resin can be produced by copolymerizing an unsaturated monomer having a group containing a carbonyl group (e.g., an amide group, an acyl group, an aldehyde group, etc.) with vinyl acetate, followed by saponification. Specific examples of carbonyl group-modified polyvinyl alcohol resins include the "D Polymer" series manufactured by Nippon Vinyl Acetate & Poval Co., Ltd. Other examples include resins described in JP-A-8-151412 and JP-A-9-324095.

[0036] Sulfonic acid-modified polyvinyl alcohol resins have sulfo groups (-SO2OH) in addition to the hydroxyl groups that make up the polyvinyl alcohol backbone. Sulfonic acid-modified polyvinyl alcohol resins can be produced by copolymerizing an unsaturated monomer having a sulfo group with vinyl acetate, followed by saponification. The sulfonic acid-modified polyvinyl alcohol resin may be a commercially available product, such as "L-3266" from Mitsubishi Chemical Corporation or the "AS-Polymer" series from Nippon Vinyl Acetate & Poval Co., Ltd.

[0037] The alkyl group-modified polyvinyl alcohol resin has an alkyl group in addition to the hydroxyl group constituting the polyvinyl alcohol skeleton. The alkyl group-modified polyvinyl alcohol resin can be produced by copolymerizing an unsaturated monomer having an alkyl group with vinyl acetate, followed by saponification. The alkyl group-modified polyvinyl alcohol resin may be a commercially available product, such as the "Z-Polymer" series from Nippon Vinyl Acetate & Poval Co., Ltd.

[0038] The silyl-modified polyvinyl alcohol resin has a silyl group in addition to the hydroxyl group constituting the polyvinyl alcohol skeleton. The silyl-modified polyvinyl alcohol resin can be produced by copolymerizing an unsaturated monomer having a silyl group with vinyl acetate, followed by saponification. Examples of silyl group-modified polyvinyl alcohol resins include the silyl group-modified polyvinyl alcohol resins described in International Publication No. 2014 / 112625. Commercially available products may also be used, such as "R-1130," "R-2105," and "R-2130" manufactured by Kuraray Co., Ltd.

[0039] The polyethylene glycol group-modified polyvinyl alcohol resin has a polyethylene glycol group in addition to the hydroxyl group constituting the polyvinyl alcohol skeleton. The polyethylene glycol group-modified polyvinyl alcohol resin can be produced by copolymerizing an unsaturated monomer having a polyethylene glycol group with vinyl acetate, followed by saponification. The polyethylene glycol group-modified polyvinyl alcohol resin may be a commercially available product, such as the "E Polymer" series from Nippon Vinyl Acetate & Poval Co., Ltd.

[0040] Ethylene oxide group-modified polyvinyl alcohol resins have ethylene oxide groups (i.e., epoxy groups) in addition to the hydroxyl groups that constitute the polyvinyl alcohol skeleton. Polyethylene glycol group-modified polyvinyl alcohol resins can be produced by copolymerizing an unsaturated monomer having an ethylene oxide group with vinyl acetate, followed by saponification. A hydrazide group-modified polyvinyl alcohol resin has a hydrazide group (-CONR'NR'') in addition to the hydroxyl groups that constitute the polyvinyl alcohol skeleton. Here, R' and R'' each independently represent a hydrogen atom or a hydrocarbon group. A hydrazide group-modified polyvinyl alcohol resin can be produced by copolymerizing an unsaturated monomer having a hydrazide group with vinyl acetate, followed by saponification. The phosphate-modified polyvinyl alcohol resin has a phosphate ester group (-O-PO-(OR)2) in addition to the hydroxyl groups that constitute the polyvinyl alcohol skeleton. Here, each R independently represents a hydrogen atom or a hydrocarbon group. The phosphate-modified polyvinyl alcohol resin can be produced by copolymerizing an unsaturated monomer having a phosphate ester group with vinyl acetate, followed by saponification.

[0041] The polyvinyl alcohol-based resin modified with a group having a urethane bond is a resin that has a group having a urethane bond (a group represented by -CONHR) in addition to the hydroxyl group that constitutes the polyvinyl alcohol skeleton.

[0042] The polyvinyl alcohol-based resin may contain two or more of the above-mentioned modified polyvinyl alcohol-based resins, or may contain both an unmodified polyvinyl alcohol-based resin (specifically, a completely or partially saponified polyvinyl acetate) and the above-mentioned modified polyvinyl alcohol-based resin.

[0043] Commercially available polyvinyl alcohol resins may be used. Specific examples include polyvinyl alcohols with a high degree of saponification, such as "PVA-117H" sold by Kuraray Co., Ltd. and "GOHSENOL NH-20" sold by Nippon Synthetic Chemical Industry Co., Ltd., acetoacetyl-modified polyvinyl alcohols, such as the "GOHSEFIRMER Z" series sold by Nippon Synthetic Chemical Industry Co., Ltd., anion-modified polyvinyl alcohols, such as "KL-318" and "KM-118" sold by Kuraray Co., Ltd. and "GOHSENAL T-330" sold by Nippon Synthetic Chemical Industry Co., Ltd., and cation-modified polyvinyl alcohols, such as "CM-318" sold by Kuraray Co., Ltd. and "GOHSEFIRMER K-210" sold by Nippon Synthetic Chemical Industry Co., Ltd.

[0044] [1-3] Polyvinyl acetal resin By using a polyvinyl acetal resin as the aqueous resin (A), it is easy to improve the optical durability of the optical laminate in a high-temperature and high-humidity environment, the adhesion between the optical layer and the first cured material layer in the optical laminate, and the adhesion between the first cured material layer and the first thermoplastic resin film.

[0045] The polyvinyl acetal resin can be obtained by acetalizing a polyvinyl alcohol resin with at least one of an aldehyde and a ketone. The polyvinyl acetal resin may be used alone or in combination of two or more.

[0046] The degree of saponification of the polyvinyl alcohol resin used to obtain the polyvinyl acetal resin is not particularly limited, but is usually 70 mol% or more, preferably 75 mol% or more, and more preferably 80 mol% or more, and is usually 99.9 mol% or less, and may be 99.8 mol% or less.

[0047] The aldehyde used to obtain the polyvinyl acetal resin is not particularly limited, but examples thereof include aldehydes having a chain aliphatic group, a cyclic aliphatic group, or an aromatic group having 1 to 10 carbon atoms. Examples of these aldehydes include aliphatic aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-valeraldehyde, n-hexylaldehyde, 2-ethylbutyraldehyde, 2-ethylhexylaldehyde, n-heptylaldehyde, n-octylaldehyde, n-nonylaldehyde, n-decylaldehyde, and amylaldehyde; and aromatic aldehydes such as benzaldehyde, cinnamaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxybenzaldehyde, m-hydroxybenzaldehyde, phenylacetaldehyde, and β-phenylpropionaldehyde. These aldehydes can be used alone or in combination of two or more. Among these aldehydes, butyl aldehyde, 2-ethylhexyl aldehyde, and n-nonyl aldehyde, which have excellent acetalization reactivity, are preferred, and butyl aldehyde is more preferred.

[0048] The ketone used to obtain the polyvinyl acetal resin is not particularly limited, but examples thereof include acetone, ethyl methyl ketone, diethyl ketone, t-butyl ketone, dipropyl ketone, allyl ethyl ketone, acetophenone, p-methylacetophenone, 4'-aminoacetophenone, p-chloroacetophenone, 4'-methoxyacetophenone, 2'-hydroxyacetophenone, 3'-nitroacetophenone, P-(1-piperidino)acetophenone, benzalacetophenone, propiophenone, benzophenone, 4-nitrobenzophenone, 2-methylbenzophenone, p-bromobenzophenone, cyclohexyl(phenyl)methanone, 2-butyronaphthone, 1-acetonaphthone, 2-hydroxy-1-acetonaphthone, and 8'-hydroxy-1'-benzonaphthone.

[0049] The amount of aldehyde and ketone added can be appropriately set depending on the desired degree of acetalization of the polyvinyl acetal resin. For example, the total amount of aldehyde and ketone can be 60 to 95 mol %, preferably 70 to 90 mol %, based on 100 mol % of the polyvinyl alcohol resin.

[0050] The amount of hydroxyl groups in the polyvinyl acetal resin is preferably 30 mol% or more, more preferably 40 mol% or more, and may be 50 mol% or more, and is preferably 90 mol% or less, more preferably 85 mol% or less. The amount of hydroxyl groups in the polyvinyl acetal resin is the ratio (mol%) of the amount of ethylene groups to which hydroxyl groups are bonded to the total amount of ethylene groups in the main chain, and can be calculated, for example, by a method in accordance with JIS K6728 "Testing Methods for Polyvinyl Butyral."

[0051] The amount of acetyl groups in the polyvinyl acetal resin is not particularly limited, but is preferably 0.0001 mol% or more, more preferably 0.001 mol% or more, and may be 0.01 mol% or more, and is preferably 5 mol% or less, more preferably 3 mol% or less, and may be 2 mol% or less. The amount of acetyl groups in the polyvinyl acetal resin is the ratio (mol%) of the amount of ethylene groups to the total amount of ethylene groups in the main chain, calculated by subtracting the total amount of ethylene groups, including the amount of ethylene groups bonded to acetal groups and the amount of ethylene groups bonded to hydroxyl groups, from the total amount of ethylene groups in the main chain. The amount of ethylene groups bonded to acetal groups can be calculated, for example, by a method in accordance with JIS K6728 "Test Methods for Polyvinyl Butyral."

[0052] [2] Silane compound having a silanol group (B) The silane compound (B) is a compound having a silanol group (—SiOH). The curable composition (S) may contain one or more silane compounds (B). By adding the silane compound (B) to the curable composition (S), the optical durability of the optical laminate under high-temperature and high-humidity environments can be improved.

[0053] The silane compound (B) is not particularly limited as long as it has a silanol group. In addition, even if silane compounds having silanol groups form a dimer, a trimer, or a three-dimensional network structure by a condensation reaction, the formed product is included in the silane compound (B) in this specification as long as it contains a silanol group.

[0054] The silane compound (B) preferably has, in addition to a silanol group, one or more functional groups selected from the group consisting of an amino group, a carboxyl group, an epoxy group, an acetoacetyl group, a hydroxyalkyl group, a mercapto group, an oxyalkylene group, and an alkenyl group, which may have a substituent. Of these, the silane compound (B) more preferably has at least one functional group selected from an amino group and a carboxyl group, which may have a substituent, and even more preferably has a carboxyl group. Examples of the amino group which may have a substituent include an amino group (-NH2) which has no substituent, an alkylamino group in which one or two hydrogen atoms are substituted with an alkyl group, a (hydroxyalkyl)amino group in which one or two hydrogen atoms are substituted with a hydroxyalkyl group (e.g., -N(CH2HC(OH)CH2OH2)2), and an aminoalkylamino group (-NHC2H4NH2). Specific examples of the functional group include -NH2, -NHC2H4NH2, -COOH, -SH, -CH(OH)CH2OH, -N(CH2HC(OH)CH2OH2)2, and -CHCH2.

[0055] When the silane compound (B) has two or more of the above functional groups, the functional groups may be the same as or different from each other. When the silane compound (B) has the above-mentioned functional group, it is easy to improve the optical durability of the optical laminate in a high-temperature and high-humidity environment, the adhesion between the optical layer and the first cured material layer in the optical laminate, and the adhesion between the first cured material layer and the first thermoplastic resin film.

[0056] The silane compound (B) preferably contains a Si-O-Si bond in addition to the silanol group and the above-mentioned functional group. The silanol group and the above-mentioned functional group may be present anywhere in the structure of the silane compound (B) containing the Si-O-Si bond, but it is preferable that the silane compound (B) contains the above-mentioned functional group at the terminal of the silane compound (B) containing the Si-O-Si bond.

[0057] From the viewpoint of improving the optical durability of the optical laminate in a high-temperature, high-humidity environment, the content of the silane compound (B) is usually 0.5 parts by mass or more, preferably 1 part by mass or more, and more preferably 3 parts by mass or more, relative to 100 parts by mass of the aqueous resin (A), and is usually 200 parts by mass or less, preferably 180 parts by mass or less, and more preferably 150 parts by mass or less. By setting the content of the silane compound (B) in the curable composition (S) within the above range, it is possible to improve the optical durability of the optical laminate in a high-temperature, high-humidity environment, while obtaining good adhesion between the optical layer and the first cured product layer in the optical laminate, and between the first cured product layer and the first thermoplastic resin film. However, if the content of the silane compound (B) is too low, it is difficult to obtain the optical durability of the optical laminate under high-temperature and high-humidity environments, whereas if the content of the silane compound (B) is too high, the optical durability of the optical laminate under high-temperature and high-humidity environments tends to be easily reduced.

[0058] [3] Other ingredients The curable composition (S) may contain other components in addition to the aqueous resin (A) and the silane compound (B). Examples of other components include curable components and crosslinking agents such as polyhydric aldehydes such as glyoxal and glyoxal derivatives, melamine compounds, aziridine compounds, water-soluble epoxy resins, and metal compounds such as zirconium compounds, zinc compounds, titanium compounds, and aluminum compounds; modified polyvinyl alcohol polymers other than carboxyl group-modified polyvinyl alcohol polymers; additives such as coupling agents, tackifiers, antioxidants, ultraviolet absorbers, heat stabilizers, and hydrolysis inhibitors; aqueous solvents; and compound (C) described below. The curable composition (S) may contain one or more other components.

[0059] [3-1] Aqueous solvents The curable composition (S) preferably contains an aqueous solvent for dissolving or dispersing the aqueous resin (A). The aqueous solvent may be any of those exemplified above. The aqueous solvent preferably contains water in an amount of 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, based on the total mass of the aqueous solvent. Alternatively, the aqueous solvent may contain only water. The solid content concentration of the curable composition (S) is usually 0.5% by mass or more and 20% by mass or less, and preferably 1% by mass or more and 15% by mass or less.

[0060] [3-2] Compound (C) When the aqueous resin (A) contains an oxazolyl group-containing (meth)acrylic resin and the silane compound (B) has the above-mentioned functional group, it is preferable to contain a compound (hereinafter sometimes referred to as "compound (C)") that promotes the reaction between the oxazolyl group of the oxazolyl group-containing (meth)acrylic resin and the above-mentioned functional group of the silane compound (B). The promotion here also includes the initiation of the reaction.

[0061] The curable composition (S) may contain one type of compound (C), or may contain two or more types of compounds (C). The compound (C) may be incorporated into the curable composition (S) as a solution (for example, an aqueous solution) containing the compound (C).

[0062] Suitable examples of the compound (C) include acid compounds, which may function as a catalyst for the reaction between the oxazolyl group of the oxazolyl group-containing (meth)acrylic resin and the above-described functional group of the silane compound (B).

[0063] Examples of the acid compound include inorganic acids such as sulfuric acid, hydrogen chloride, nitric acid, phosphoric acid, phosphorous acid, and boric acid; and organic acids such as p-toluenesulfonic acid, dodecylbenzenesulfonic acid, naphthalenesulfonic acid, methanesulfonic acid, benzenesulfonic acid, phenylphosphoric acid, sulfanilic acid, phenylphosphonic acid, acetic acid, and propionic acid. Among these, the acid compound is preferably a relatively strong acid from the viewpoint of improving the optical durability of the optical laminate in a high-temperature, high-humidity environment, the adhesion between the optical layer and the first cured material layer in the optical laminate, and the adhesion between the first cured material layer and the first thermoplastic resin film. Examples of such acid compounds include sulfuric acid, hydrogen chloride (hydrochloric acid), nitric acid, and p-toluenesulfonic acid. Use of such a strong acid as the acid compound tends to improve adhesion, particularly between the optical layer and the first cured material layer in the optical laminate, and between the first cured material layer and the first thermoplastic resin film.

[0064] The content of the acid compound is preferably 5 parts by mass or more and 80 parts by mass or less, more preferably 10 parts by mass or more and 70 parts by mass or less, and even more preferably 15 parts by mass or more and 60 parts by mass or less, relative to 100 parts by mass of the oxazolyl group-containing (meth)acrylic resin. If the content of the acid compound is too low, it is difficult to obtain at least one of adhesion between the optical layer and the first cured product layer in the optical laminate and between the first cured product layer and the first thermoplastic resin film, whereas if the content of the acid compound is too high, it is likely that at least one of adhesion between the optical layer and the first cured product layer in the optical laminate and between the first cured product layer and the first thermoplastic resin film will be reduced.

[0065] <Optical laminate> The optical laminate according to the present invention comprises an optical layer and a first cured product layer (a cured product layer made of a cured product of the curable composition (S)) laminated on at least one surface of the optical layer. According to the present invention, the cured product layer contained in the optical laminate is composed of a cured product of the curable composition (S), and therefore the optical durability of the optical laminate in a high-temperature, high-humidity environment can be improved.

[0066] [1] Structure of optical laminate Examples of layer configurations of optical laminates are shown in FIGS. 1 includes an optical layer 30 and a first cured product layer 15 laminated on one surface of the optical layer 30. The first cured product layer 15 can function as an overcoat layer that covers and protects the surface of the optical layer 30, an optical functional layer that imparts additional optical functions to the optical layer 30, or the like. The optical layer 30 and the first cured product layer 15 are preferably in direct contact with each other.

[0067] 2 includes an optical layer 30 and a first thermoplastic resin film 10 laminated to one surface of the optical layer 30 via a first cured product layer 15. The first cured product layer 15 can function as an adhesive layer that bonds the optical layer 30 and the first thermoplastic resin film 10 together. The first cured material layer 15 and the first thermoplastic resin film 10 are preferably in direct contact with each other. The optical layer 30 and the first cured product layer 15 are preferably in direct contact with each other.

[0068] 3 includes an optical layer 30, a first thermoplastic resin film 10 laminated to one surface of the optical layer 30 via a first cured product layer 15, and a second thermoplastic resin film 20 laminated to the other surface of the optical layer 30 via a second cured product layer 25. That is, the optical laminate according to the present invention may include the second thermoplastic resin film 20, the second cured product layer 25, the optical layer 30, the first cured product layer 15, and the first thermoplastic resin film 10, in this order. The first cured product layer 15 and the second cured product layer 25 can function as an adhesive layer that bonds the optical layer 30 to the first thermoplastic resin film 10 and an adhesive layer that bonds the optical layer 30 to the second thermoplastic resin film 20, respectively. The second cured material layer 25 and the second thermoplastic resin film 20 are preferably in direct contact with each other. The optical layer 30 and the second cured product layer 25 are preferably in direct contact with each other.

[0069] 4 includes an optical layer 30, a first cured product layer 15 laminated on one surface of the optical layer 30, and a second thermoplastic resin film 20 laminated to the other surface of the optical layer 30 via a second cured product layer 25. The first cured product layer 15 can function as an overcoat layer that covers and protects the surface of the optical layer 30, an optical functional layer that imparts additional optical functions to the optical layer 30, etc. The second cured product layer 25 can function as an adhesive layer that bonds the optical layer 30 and the second thermoplastic resin film 20 together. The optical layer 30 and the first cured product layer 15 are preferably in direct contact with each other. The second cured material layer 25 and the second thermoplastic resin film 20 are preferably in direct contact with each other. The optical layer 30 and the second cured product layer 25 are preferably in direct contact with each other.

[0070] 5 includes an optical layer 30, a first cured material layer 15 laminated on one surface of the optical layer 30, and a second cured material layer 25 laminated on the other surface of the optical layer 30. The first cured material layer 15 and the second cured material layer 25 can function as an overcoat layer that covers and protects the surface of the optical layer 30, an optical functional layer that imparts additional optical functions to the optical layer 30, or the like. The optical layer 30 and the first cured product layer 15 are preferably in direct contact with each other. The optical layer 30 and the second cured product layer 25 are preferably in direct contact with each other.

[0071] The optical layer 30 may be any of various optical films (films having optical properties) that can be incorporated into image display devices such as liquid crystal display devices. Examples of the optical layer 30 include a polarizer, a retardation film, a brightness enhancement film, an antiglare film, an antireflection film, a diffusion film, and a light-collecting film.

[0072] The optical laminate may contain layers (or films) other than those described above. Examples of the other layers include a pressure-sensitive adhesive layer laminated on the outer surface of the first thermoplastic resin film 10, the second thermoplastic resin film 20, the first cured material layer 15, the second cured material layer 25, and / or the optical layer 30; a separate film (also called a "release film") laminated on the outer surface of the pressure-sensitive adhesive layer; a protect film (also called a "surface protection film") laminated on the outer surface of the first thermoplastic resin film 10, the second thermoplastic resin film 20, the first cured material layer 15, the second cured material layer 25, and / or the optical layer 30; and an optically functional film (or layer) laminated on the outer surface of the first thermoplastic resin film 10, the second thermoplastic resin film 20, the first cured material layer 15, the second cured material layer 25, and / or the optical layer 30 via an adhesive layer or a pressure-sensitive adhesive layer.

[0073] [2] Polarizer A polarizer is a layer or film that has the function of selectively transmitting linearly polarized light in one direction from natural light. An example of a polarizer is a film in which a dichroic dye is adsorbed and oriented on a polyvinyl alcohol-based resin film, and examples of the dichroic dye include iodine and dichroic organic dyes. The polarizer may also be a coating type polarizing film in which a dichroic dye in a lyotropic liquid crystal state is coated on a substrate film and then aligned and fixed. The polarizers described above are called absorption polarizers because they selectively transmit linearly polarized light in one direction from natural light and absorb linearly polarized light in the other direction.

[0074] The polarizer is not limited to an absorptive polarizer, and may be a reflective polarizer that selectively transmits linearly polarized light in one direction from natural light and reflects linearly polarized light in the other direction, or a scattering polarizer that scatters linearly polarized light in the other direction, but an absorptive polarizer is preferred from the viewpoint of excellent visibility. Among them, a polyvinyl alcohol-based polarizing film made of a polyvinyl alcohol-based resin film is more preferred, a polyvinyl alcohol-based polarizing film in which a dichroic pigment such as iodine or a dichroic dye is adsorbed and oriented in a polyvinyl alcohol-based resin film is even more preferred, and a polyvinyl alcohol-based polarizing film in which iodine is adsorbed and oriented in a polyvinyl alcohol-based resin film is particularly preferred.

[0075] The polyvinyl alcohol resin may be a saponified polyvinyl acetate resin. Examples of the polyvinyl acetate resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate with other monomers copolymerizable with 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.

[0076] The saponification degree of the polyvinyl alcohol resin is usually 85 mol% or more and 100 mol% or less, preferably 98 mol% or more. The polyvinyl alcohol resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes can also be used. The average polymerization degree of the polyvinyl alcohol resin is usually 1,000 or more and 10,000 or less, preferably 1,500 or more and 5,000 or less. The average degree of polymerization of the polyvinyl alcohol resin can be determined in accordance with JIS K 6726:1994.

[0077] Such a polyvinyl alcohol-based resin film is used as a raw film for a polarizing film composed of a polyvinyl alcohol-based resin film. The method for forming the polyvinyl alcohol-based resin film is not particularly limited, and known methods can be used. The thickness of the polyvinyl alcohol-based raw film is, for example, 150 μm or less, preferably 100 μm or less (e.g., 50 μm or less), and 5 μm or more.

[0078] A polarizing film made of a polyvinyl alcohol-based resin film can be produced by a known method, specifically, a method including the steps of uniaxially stretching a polyvinyl alcohol-based resin film, dyeing the polyvinyl alcohol-based resin film with a dichroic dye to adsorb the dichroic dye, treating the polyvinyl alcohol-based resin film with an aqueous boric acid solution (crosslinking treatment), and washing with water after the treatment with the aqueous boric acid solution.

[0079] The thickness of the polarizer can be 40 μm or less, preferably 30 μm or less (e.g., 20 μm or less, further 15 μm or less, even 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, thin-film polarizers can be more easily produced, and the thickness of the polarizer can be more easily set to, for example, 20 μm or less, further 15 μm or less, even further 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 an optical laminate (polarizing plate) and an image display device including the same. Generally, the thinner the polarizer, the poorer its optical durability tends to be. However, by using the curable composition of the present invention, even such a thin-film polarizer can have good durability.

[0080] [3] Retardation film Examples of the retardation film include a stretched film obtained by uniaxially or biaxially stretching a light-transmitting 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, and a film in which the above-mentioned liquid crystal layer is formed on a substrate film, etc. In this specification, a zero retardation film is also included in the retardation film. The substrate film is usually a film made of a thermoplastic resin, and an example of the thermoplastic resin is a cellulose ester resin such as triacetyl cellulose. Examples of the thermoplastic resin having light-transmitting properties include the resin constituting the first thermoplastic resin film 10 described below.

[0081] A zero retardation film is a film in which both the in-plane retardation value Re and the thickness direction retardation value Rth are -15 to 15 nm. This retardation film is suitable for use in IPS mode liquid crystal display devices. The in-plane retardation value Re and the thickness direction retardation value Rth are both preferably -10 to 10 nm, and more preferably -5 to 5 nm. The in-plane retardation value Re and the thickness direction retardation value Rth referred to here are values ​​at a wavelength of 590 nm.

[0082] The in-plane retardation value Re and the thickness direction retardation value Rth are calculated by the following formulas, respectively: Re=(n x -n y )×d Rth = (n x +n y ) / 2-n z 〕×d where n x is the refractive index in the slow axis direction (x-axis direction) in the film plane, and n y is the refractive index in the fast axis direction in the film plane (the y-axis direction perpendicular to the x-axis in the plane), and n z is the refractive index in the film thickness direction (z-axis direction perpendicular to the film surface), and d is the film thickness.

[0083] The zero retardation film may be a resin film made of, for example, a cellulose-based resin, a polyolefin-based resin such as a linear polyolefin-based resin or a cyclic polyolefin-based resin, a polyethylene terephthalate-based resin, or a (meth)acrylic resin. In particular, the cellulose-based resin, the polyolefin-based resin, or the (meth)acrylic resin is preferably used because the retardation value can be easily controlled and they are readily available.

[0084] Films that exhibit optical anisotropy through the application and orientation of liquid crystal compounds include: First embodiment: a retardation film in which rod-like liquid crystal compounds are aligned horizontally relative to a supporting substrate; Second form: a retardation film in which rod-like liquid crystal compounds are aligned in a direction perpendicular to the supporting substrate; Third form: a retardation film in which the direction of the rod-like liquid crystal compound is helically oriented in the plane; Fourth embodiment: a retardation film in which discotic liquid crystal compounds are tiltedly aligned; Fifth embodiment: A biaxial retardation film in which discotic liquid crystal compounds are aligned in the direction perpendicular to the supporting substrate can be mentioned.

[0085] For example, the first, second and fifth embodiments are preferably used as optical layers for organic electroluminescence displays, or these may be laminated together.

[0086] When the retardation film is a layer made of a polymer in an oriented state of a polymerizable liquid crystal compound (hereinafter, sometimes referred to as an "optically anisotropic layer"), the retardation film preferably has reverse wavelength dispersion. Reverse wavelength dispersion is an optical property in which the in-plane retardation value of liquid crystal alignment at short wavelengths is smaller than the in-plane retardation value of liquid crystal alignment at long wavelengths, and preferably, the retardation film satisfies the following formulas (1) and (2). Here, Re(λ) represents the in-plane retardation value for light with a wavelength of λ nm. Re(450) / Re(550)≦1 (1) 1≦Re(630) / Re(550) (2) When the retardation film has the first type and reverse wavelength dispersion, coloration during black display on a display device is reduced, which is preferable, and in formula (1), 0.82≦Re(450) / Re(550)≦0.93 is more preferable, and 120≦Re(550)≦150 is even more preferable.

[0087] When the retardation film is a film having an optically anisotropic layer, examples of the polymerizable liquid crystal compound include compounds having a polymerizable group among the compounds described in "3.8.6 Network (fully crosslinked type)" and "6.5.1 Liquid Crystal Materials b. Polymerizable Nematic Liquid Crystal Materials" in Liquid Crystal Handbook (edited by the Liquid Crystal Handbook Editorial Committee, published by Maruzen Co., Ltd. on October 30, 2000), as well as the polymerizable liquid crystal compounds described in JP 2010-31223 A, JP 2010-270108 A, JP 2011-6360 A, JP 2011-207765 A, JP 2016-81035 A, and WO 2017 / 043438 A.

[0088] Examples of a method for producing a retardation film from a polymer of a polymerizable liquid crystal compound in an aligned state include the method described in JP-A-2010-31223.

[0089] In the second embodiment, the in-plane retardation value Re(550) may be adjusted to a range of 0 to 10 nm, preferably 0 to 5 nm, and the thickness direction retardation value Rth may be adjusted to a range of -10 to -300 nm, preferably -20 to -200 nm. The thickness direction retardation value Rth, which means the refractive index anisotropy in the thickness direction, can be calculated from the retardation value R50 measured by tilting the in-plane fast axis at 50 degrees as the tilt axis and the in-plane retardation value Re. That is, the thickness direction retardation value Rth can be calculated from the in-plane retardation value Re, the retardation value R50 measured by tilting the in-plane fast axis at 50 degrees as the tilt axis, the thickness d of the retardation film, and the average refractive index n0 of the retardation film using the following formulas (4) to (6): x , n y and n z and then substitute these into equation (3) to perform the calculation.

[0090] Rth=[(n x +n y ) / 2-n z ]×d (3) Re =(n x -n y )×d (4) R50=(n x -n y ')×d / cos(φ) (5) (n x +n y +n z ) / 3=n0(6) where: φ=sin -1 [sin(40°) / n0] n y '=n y ×n z / 〔n y 2 ×sin 2 (φ)+n z 2 ×cos 2 (φ) 1 / 2

[0091] The retardation film may be a multilayer film having two or more layers, such as a retardation film having a protective film laminated on one or both sides thereof, or a retardation film having two or more retardation films laminated together via a pressure-sensitive adhesive or adhesive.

[0092] [4] First cured material layer The first cured material layer 15 is a cured material 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, for example, by heat.

[0093] [5] Thermoplastic resin film The first thermoplastic resin film 10 and the second thermoplastic resin film 20 can each be a film made of a light-transmitting (preferably optically transparent) thermoplastic resin, for example, a polyolefin resin such as a chain polyolefin resin (such as a polypropylene resin) or a cyclic polyolefin resin (such as a norbornene resin); a cellulose ester resin such as triacetyl cellulose or diacetyl cellulose; a polyester resin such as polyethylene terephthalate, polyethylene naphthalate, or polybutylene terephthalate; a polycarbonate resin; a (meth)acrylic resin; a polystyrene resin; or a mixture or copolymer thereof.

[0094] The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may each be an unstretched film, or a uniaxially or biaxially stretched film. The biaxial stretching may be simultaneous biaxial stretching in which the film is stretched in two stretching directions at the same time, or sequential biaxial stretching in which the film is stretched in a first direction and then stretched in a second direction different from the first direction. The first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 may be a protective film that plays a role in protecting the optical layer 30, or may be a protective film that also has optical functions such as a retardation film. Regarding the retardation film, the description in [4] above is cited.

[0095] Examples of the linear polyolefin resin include homopolymers of linear olefins such as polyethylene resins and polypropylene resins, as well as copolymers made of two or more types of linear olefins.

[0096] Cyclic polyolefin resin is a general term for resins containing cyclic olefins as polymerization units, such as norbornene, tetracyclododecene (also known as dimethanooctahydronaphthalene), or their derivatives. Examples of cyclic polyolefin resins include ring-opening (co)polymers of cyclic olefins and their hydrogenated products, addition polymers of cyclic olefins, copolymers of cyclic olefins with linear olefins such as ethylene and propylene or aromatic compounds having vinyl groups, and modified (co)polymers obtained by modifying these with unsaturated carboxylic acids or their derivatives. Among these, norbornene-based resins using norbornene-based monomers such as norbornene and polycyclic norbornene-based monomers as cyclic olefins are preferably used.

[0097] The cellulose ester resin is a resin in which at least a portion of the hydroxyl groups in cellulose are esterified with acetate, and may be a mixed ester in which a portion is esterified with acetate and a portion is esterified with another acid. The cellulose ester resin is preferably an acetyl cellulose resin. Examples of the acetyl cellulose resin include triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate.

[0098] The polyester resin is a resin having an ester bond other than the above-mentioned cellulose ester resin, and is generally a polycondensate of a polycarboxylic acid or a derivative thereof with a polyhydric alcohol. Examples of polyester resins include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexane dimethyl terephthalate, and polycyclohexane dimethyl naphthalate. Among these, polyethylene terephthalate is preferably used from the viewpoints of mechanical properties, solvent resistance, scratch resistance, cost, etc. Polyethylene terephthalate refers to a resin in which 80 mol % or more of the repeating units are composed of ethylene terephthalate, and may contain structural units derived from other copolymerization components (dicarboxylic acid components such as isophthalic acid; diol components such as propylene glycol, etc.).

[0099] Polycarbonate resins are polyesters formed from carbonic acid and glycol or bisphenol. Among them, aromatic polycarbonates having diphenylalkane in the molecular chain are preferably used from the viewpoints of heat resistance, weather resistance, and acid resistance. Examples of polycarbonates include polycarbonates derived from bisphenols such as 2,2-bis(4-hydroxyphenyl)propane (also known as bisphenol A), 2,2-bis(4-hydroxyphenyl)butane, 1,1-bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)isobutane, and 1,1-bis(4-hydroxyphenyl)ethane.

[0100] A (meth)acrylic resin is a polymer containing structural units derived from a (meth)acrylic monomer, and examples of the (meth)acrylic monomer include methacrylic acid esters and acrylic acid esters.

[0101] Examples of methacrylic acid esters include methyl methacrylate, ethyl methacrylate, n-, i- or t-butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, and 2-hydroxyethyl methacrylate.

[0102] Examples of acrylic acid esters include ethyl acrylate, n-, i- or t-butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, and 2-hydroxyethyl acrylate.

[0103] The (meth)acrylic resin may be a polymer consisting only of structural units derived from (meth)acrylic monomers, or may contain other structural units.

[0104] In one preferred embodiment, the (meth)acrylic resin contains methyl methacrylate or methyl methacrylate and methyl acrylate as copolymerization components. In one preferred embodiment, the (meth)acrylic resin may be a polymer containing a methacrylic acid ester as the main monomer (containing 50% by mass or more), and is preferably a copolymer in which a methacrylic acid ester is copolymerized with another copolymerization component.

[0105] The glass transition temperature of the (meth)acrylic resin is preferably 80° C. or higher and 160° C. or lower. The glass transition temperature can be controlled by adjusting the polymerization ratio of the methacrylic acid ester monomer and the acrylic acid ester monomer, the carbon chain length of each ester group and the type of functional group therein, and the polymerization ratio of the polyfunctional monomer to the total monomers.

[0106] Introducing a ring structure into the main chain of the polymer is also an effective means for increasing 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, or a lactone structure. Specific examples include cyclic acid anhydride structures such as glutaric anhydride structures and succinic anhydride structures; cyclic imide structures such as glutarimide structures and succinimide structures; and lactone ring structures such as butyrolactone and valerolactone. The glass transition temperature of the (meth)acrylic resin tends to increase as the content of the ring structure in the main chain increases. The cyclic acid anhydride structure and the cyclic imide structure can be introduced by copolymerizing a monomer having a cyclic structure, such as maleic anhydride or maleimide; by introducing the cyclic acid anhydride structure by a dehydration / demethanolization condensation reaction after polymerization; or by reacting an amino compound to introduce a cyclic imide structure. A resin (polymer) having a lactone ring structure can be obtained by preparing a polymer having a hydroxyl group and an ester group in the polymer chain, and then cyclocondensing the hydroxyl group and the ester group in the obtained polymer by heating, if necessary in the presence of a catalyst such as an organic phosphorus compound, to form a lactone ring structure.

[0107] The (meth)acrylic resin and the thermoplastic resin film formed therefrom may contain additives as needed, such as lubricants, antiblocking agents, heat stabilizers, antioxidants, antistatic agents, light resistance agents, impact modifiers, surfactants, etc. These additives can also be used when a thermoplastic resin other than a (meth)acrylic resin is used as the thermoplastic resin constituting the thermoplastic resin film.

[0108] The (meth)acrylic resin may contain acrylic rubber particles as an impact modifier from the viewpoint of film formability, impact resistance of the film, etc. The acrylic rubber particles are particles containing an acrylic acid ester-based elastic polymer as an essential component, and examples thereof include those with a single-layer structure essentially consisting of this elastic polymer, and those with a multi-layer structure having this elastic polymer as one layer.

[0109] Examples of the elastic polymer include crosslinked elastic copolymers which contain alkyl acrylate as the main component and are copolymerized with other copolymerizable vinyl monomers and crosslinkable monomers. Examples of alkyl acrylates that are the main component of the elastic polymer include those in which the alkyl group has 1 to 8 carbon atoms, such as methyl acrylate, ethyl acrylate, butyl acrylate, and 2-ethylhexyl acrylate, and alkyl acrylates having an alkyl group with 4 or more carbon atoms are preferably used.

[0110] Examples of other vinyl monomers copolymerizable with the alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, and more specifically, examples thereof include methacrylic acid esters such as methyl methacrylate; aromatic vinyl compounds such as styrene; and vinyl cyanide compounds such as acrylonitrile.

[0111] Examples of the crosslinkable monomer include crosslinkable compounds having at least two polymerizable carbon-carbon double bonds in the molecule, and more specific examples include (meth)acrylates of polyhydric alcohols such as ethylene glycol di(meth)acrylate and butanediol di(meth)acrylate; alkenyl esters of (meth)acrylic acid such as allyl (meth)acrylate; divinylbenzene; and the like.

[0112] A laminate of a film made of a (meth)acrylic resin that does not contain rubber particles and a film made of a (meth)acrylic resin that does contain rubber particles can also be used as the thermoplastic resin film to be attached to the optical layer 30. Alternatively, the thermoplastic resin film to be attached to the optical layer 30 can be one in which a (meth)acrylic resin layer is formed on one or both sides of a retardation-exhibiting layer made of a resin different from a (meth)acrylic resin, and retardation is exhibited.

[0113] The first thermoplastic resin film 10 and the second thermoplastic resin film 20 are each preferably a film containing one or more thermoplastic resins selected from the group consisting of cellulose ester resins, polyester resins, (meth)acrylic resins, and cyclic polyolefin resins, and are more preferably a cellulose ester resin film, polyester resin film, (meth)acrylic resin film, or cyclic polyolefin resin film.

[0114] The first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 may contain an ultraviolet absorber, an infrared absorber, an organic dye, a pigment, an inorganic dye, an antioxidant, an antistatic agent, a surfactant, a lubricant, a dispersant, a heat stabilizer, etc. When the optical laminate is applied to an image display device, by placing a thermoplastic resin film containing an ultraviolet absorber on the viewing side of an image display element (for example, a liquid crystal cell or an organic EL display element), deterioration of the image display element due to ultraviolet rays can be suppressed. Examples of the ultraviolet absorber include salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, and nickel complex salt compounds.

[0115] The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be films made of the same thermoplastic resin or 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, the presence or absence and type of additives, retardation properties, etc.

[0116] The first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 may have a surface treatment layer (coating layer) such as a hard coat layer, an antiglare layer, an antireflection layer, a light diffusion layer, an antistatic layer, an antifouling layer, or a conductive layer on its outer surface (the surface opposite the optical layer 30).

[0117] The thickness of each of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is typically 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 even more preferably 15 μm or more and 65 μm or less. The thickness of each of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be 50 μm or less, or may be 40 μm or less. Reducing the thickness of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is advantageous for reducing the thickness of the optical laminate (polarizing plate) and the image display device including the same.

[0118] The surfaces of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 to which the curable composition is applied may be subjected to a surface modification treatment such as saponification treatment, plasma treatment, corona treatment, or primer treatment from the viewpoint of improving adhesion, or may not be subjected to a surface modification treatment from the viewpoint of simplifying the process. The surface modification treatment may be performed on the bonding surface of the optical layer 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 resin film, it is preferable to perform a saponification treatment from the viewpoint of improving adhesion. Examples of the saponification treatment include a method of immersing the film in an aqueous alkali solution such as sodium hydroxide or potassium hydroxide.

[0119] [6] Second cured material layer The curable composition forming the second cured material layer 25 may be the above-mentioned curable composition (S) or a different curable composition. From the viewpoint of the optical durability of the optical laminate under a high-temperature and high-humidity environment, the second cured material layer 25 is preferably a cured material layer of the curable composition (S). When the first cured material layer 15 and the second cured material layer 25 are formed from the curable composition (S), these curable compositions may have the same composition or different compositions. Other curable compositions include known aqueous compositions (including aqueous adhesives) in which a curable resin component is dissolved or dispersed in water, and known active energy ray-curable compositions (including active energy ray-curable adhesives) containing an active energy ray-curable compound.

[0120] Examples of the resin component contained in the aqueous composition include polyvinyl alcohol resins and urethane resins. The aqueous composition containing the polyvinyl alcohol-based resin may further contain a curable component or a crosslinking agent, such as a polyaldehyde, a melamine-based compound, a zirconia compound, a zinc compound, glyoxal, a glyoxal derivative, or a water-soluble epoxy resin, in order to improve adhesion and bonding properties. An example of an aqueous composition containing a urethane resin is an aqueous composition containing a polyester ionomer urethane resin and a compound having a glycidyloxy group. The polyester ionomer urethane resin is a urethane resin having a polyester skeleton into which a small amount of an ionic component (hydrophilic component) has been introduced.

[0121] 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, X-rays, etc. When an active energy ray-curable composition is used, the second cured product layer 25 is a cured product layer of the composition.

[0122] The active energy ray-curable composition may be a composition containing an epoxy compound that cures by cationic polymerization as a curable component, and is preferably an ultraviolet-curable composition containing such an epoxy compound as a curable component. The epoxy compound refers to a compound having an average of one or more, preferably two or more, epoxy groups in the molecule. Only one type of epoxy compound may be used, or two or more types may be used in combination.

[0123] Examples of epoxy compounds include hydrogenated epoxy compounds (glycidyl ethers of polyols having alicyclic rings) obtained by reacting epichlorohydrin with an alicyclic polyol obtained by hydrogenating the aromatic rings of an aromatic polyol; aliphatic epoxy compounds such as polyglycidyl ethers of aliphatic polyhydric alcohols or their alkylene oxide adducts; and alicyclic epoxy compounds, which are epoxy compounds having one or more epoxy groups bonded to an alicyclic ring in the molecule.

[0124] The active energy ray-curable composition may contain a radically polymerizable (meth)acrylic compound as a curable component, instead of or in addition to the epoxy compound. Examples of the (meth)acrylic compound include (meth)acryloyloxy group-containing compounds such as (meth)acrylate monomers having one or more (meth)acryloyloxy groups in the molecule, and (meth)acrylate oligomers obtained by reacting two or more functional group-containing compounds and having at least two (meth)acryloyloxy groups in the molecule.

[0125] When the active energy ray-curable composition contains an epoxy compound that cures 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 acetophenone-based initiators, benzophenone-based initiators, benzoin ether-based initiators, thioxanthone-based initiators, xanthone, fluorenone, camphorquinone, benzaldehyde, and anthraquinone.

[0126] The optical laminate may include a pressure-sensitive adhesive layer instead of the second cured product layer 25. That is, the second thermoplastic resin film 20 may be attached to the optical layer 30 via a pressure-sensitive adhesive layer. For the pressure-sensitive adhesive layer, the description of the pressure-sensitive adhesive layer described below is cited.

[0127] [7] Production of optical laminates By laminating and adhering a first thermoplastic resin film 10 to one surface of the optical layer 30 via a first cured material layer 15, an optical laminate having the configuration shown in FIG. 2 can be obtained, and by further laminating and adhering a second thermoplastic resin film 20 to the other surface of the optical layer 30 via a second cured material layer 25, an optical laminate having the configuration shown in FIG. 3 can be obtained. When producing an optical laminate having both a first thermoplastic resin film 10 and a second thermoplastic resin film 20, these films may be laminated and bonded one side at a time in stages, or both films may be laminated and bonded simultaneously.

[0128] A method for bonding the optical layer 30 and the first thermoplastic resin film 10 includes applying the curable composition (S) to one or both of the bonding surfaces of the optical layer 30 and the first thermoplastic resin film 10, laminating the other bonding surface thereon, and pressing them together from above and below using, for example, a laminating roll or the like. The curable composition (S) can be applied by various coating methods, such as a doctor blade, a wire bar, a die coater, a comma coater, a gravure coater, etc. Alternatively, the curable composition (S) may be cast between the optical layer 30 and the first thermoplastic resin film 10 while the two are continuously supplied with their bonding surfaces facing inward.

[0129] After laminating the optical layer 30 and the first thermoplastic resin film 10, it is preferable to subject the laminate including the optical layer 30, the first cured material layer 15, and the first thermoplastic resin film 10 to a heat treatment. The temperature for the heat treatment is, for example, 40°C or higher and 100°C or lower, and preferably 50°C or higher and 90°C or lower. The heat treatment can remove the solvent contained in the curable composition layer. Furthermore, the heat treatment can promote the curing and crosslinking reaction of the curable composition.

[0130] The above-mentioned bonding method can also be applied to bonding the optical layer 30 and the second thermoplastic resin film 20 together.

[0131] When an active energy ray-curable composition is used as the curable composition constituting the second cured material layer, the curable composition layer is dried as necessary, and then irradiated with active energy rays to cure the curable composition layer. The light source used for irradiating the active energy rays may be any light source capable of generating ultraviolet rays, electron beams, X-rays, etc. In particular, light sources having an emission distribution of wavelengths of 400 nm or less, such as 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, and metal halide lamps, are preferably used.

[0132] 1, an optical laminate having no first thermoplastic resin film on the first cured product layer 15 can be produced by applying the curable composition (S) to the surface of the optical layer 30 and then subjecting the resulting laminate to a heat treatment, for example, at 80°C for 300 seconds in a hot air dryer. Alternatively, the optical laminate shown in FIG. 1 can also be produced by producing a laminate consisting of a separate film / curable composition (S) / optical layer 30, peeling off the separate film, and then subjecting the laminate to a heat treatment.

[0133] The thickness of the first cured material layer 15 or the second cured material layer 25 formed from the curable composition (S) is, for example, 1 nm or more and 20 μm or less, preferably 5 nm or more and 10 μm or less, more preferably 10 nm or more and 5 μm or less, and even more preferably 20 nm or more and 1 μm or less. The cured material layer formed from the above-mentioned known aqueous composition can also have a thickness of the same order. The thickness of the cured layer formed from the active energy ray-curable composition is, for example, 10 nm to 20 μm, preferably 100 nm to 10 μm, and more preferably 500 nm to 5 μm. The first cured material layer 15 and the second cured material layer 25 may have the same thickness or different thicknesses.

[0134] [8] Other components of the optical laminate [8-1] Optically functional films The optical laminate may include optically functional films other than the optical layer 30 (for example, a polarizer) in order to impart desired optical functions, and a suitable example of such films is a retardation film. As described above, the first thermoplastic resin film 10 and / or the second thermoplastic resin film 20 can also serve as a retardation film, but a retardation film can also be laminated separately from these films. In the latter case, the retardation film can be laminated on the outer surface of the first thermoplastic resin film 10, the second thermoplastic resin film 20, the first cured material layer 15 and / or the second cured material layer 25 via a pressure-sensitive adhesive layer or an adhesive layer. For the retardation film, the description in [4] above is cited.

[0135] Examples of other optically functional films (optical components) that can be included in optical laminates such as polarizing plates include light collecting plates, brightness enhancing films, reflective layers (reflective films), semi-transmissive reflective layers (semi-transmissive reflective films), and light diffusing layers (light diffusing films).

[0136] The light collecting plate is used for the purpose of controlling the optical path, and can be a prism array sheet, a lens array sheet, a dotted sheet, or the like.

[0137] Brightness enhancement films are used to improve the brightness of image display devices that use optical laminates such as polarizing plates. Specific examples include reflective polarization separation sheets designed to generate anisotropy in reflectance by laminating multiple thin films with different refractive index anisotropies, and circular polarization separation sheets in which an oriented film of a cholesteric liquid crystal polymer or an oriented liquid crystal layer of the cholesteric liquid crystal polymer is supported on a substrate film.

[0138] The reflective layer, semi-transmissive reflective layer, and light diffusion layer are provided to make the polarizing plate a reflective, semi-transmissive, or diffusive optical component, respectively. Reflective polarizing plates are used in liquid crystal display devices that display by reflecting incident light from the viewing side, and can omit a light source such as a backlight, making it easy to make the liquid crystal display device thinner. Semi-transmissive polarizing plates are used in liquid crystal display devices that function as a reflective type in bright places and display using light from a backlight in dark places. Diffusive polarizing plates are used in liquid crystal display devices that are imparted with light diffusion properties to suppress display defects such as moire. The reflective layer, semi-transmissive reflective layer, and light diffusion layer can be formed by known methods.

[0139] [8-2] Adhesive layer The optical laminate may include a pressure-sensitive adhesive layer. Examples of the pressure-sensitive adhesive layer include a pressure-sensitive adhesive layer for attaching the optical laminate to an image display element such as a liquid crystal cell or an organic EL display element, or to another optical component. The pressure-sensitive adhesive layer may be laminated on the outer surface of the optical layer 30 in the optical laminates having the configurations shown in FIGS. 1 and 2, on the outer surface of the first thermoplastic resin film 10 or the second thermoplastic resin film 20 in the optical laminate having the configuration shown in FIG. 3, on 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, or on the outer surface of the first cured product layer 15 or the second cured product layer 25 in the optical laminate having the configuration shown in FIG. 5. FIG. 6 shows an example in which a 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.

[0140] The pressure-sensitive adhesive used in the pressure-sensitive adhesive layer may be one having a base polymer such as a (meth)acrylic resin, a silicone resin, a polyester resin, a polyurethane resin, or a polyether resin. Among these, (meth)acrylic pressure-sensitive adhesives are preferred from the viewpoints of transparency, adhesive strength, reliability, weather resistance, heat resistance, reworkability, etc. For the (meth)acrylic pressure-sensitive adhesive, a (meth)acrylic resin having a weight-average molecular weight of 100,000 or more is useful as a base polymer, which is prepared by blending a (meth)acrylic acid alkyl ester having an alkyl group with 20 or less carbon atoms, such as a methyl group, an ethyl group, or an n-, i-, or t-butyl group, with a functional group-containing (meth)acrylic monomer, such as (meth)acrylic acid or hydroxyethyl (meth)acrylate, so that the glass transition temperature is preferably 25°C or less, more preferably 0°C or less.

[0141] The formation of a pressure-sensitive adhesive layer on the optical laminate can be carried out, for example, by a method in which a 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 then directly applied to the target surface of the optical laminate to form a pressure-sensitive adhesive layer, or by a method in which a pressure-sensitive adhesive layer is formed in sheet form on a release-treated separate film, which is then transferred to the target surface of the optical laminate. The thickness of the pressure-sensitive adhesive layer is determined depending on its adhesive strength and the like, but is suitably in the range of 1 μm to 50 μm, preferably 2 μm to 40 μm.

[0142] The optical laminate may include the above-mentioned separate film. The separate film may be a film made of a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, a polyester-based resin such as polyethylene terephthalate, or the like. Among them, a stretched film of polyethylene terephthalate is preferred.

[0143] The pressure-sensitive adhesive layer may contain, as needed, fillers such as glass fibers, glass beads, resin beads, metal powders and other inorganic powders, pigments, colorants, antioxidants, ultraviolet absorbers, antistatic agents and the like.

[0144] [8-3] Protective film The optical laminate may include a protection film for protecting its surface (typically, the surface of the first thermoplastic resin film 10, the second thermoplastic resin film 20, the first cured material layer 15, and / or the second cured material layer 25). After the optical laminate is attached to, for example, an image display element or other optical member, the protection film is peeled off and removed together with the pressure-sensitive adhesive layer that it has.

[0145] The protective film is composed of, for example, a substrate film and an adhesive layer laminated thereon. The adhesive layer is as described above. The resin constituting the base film may be, for example, a thermoplastic resin such as a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, a polyester-based resin such as polyethylene terephthalate or polyethylene naphthalate, or a polycarbonate-based resin. A polyester-based resin such as polyethylene terephthalate is preferred.

[0146] <Image display device> The optical laminate according to the present invention can be applied to image display devices such as liquid crystal display devices and organic electroluminescence (EL) display devices. In this case, the image display device includes the optical laminate and an image display element. Examples of the image display element include a liquid crystal cell and an organic EL display element. Conventionally known image display elements can be used as these image display elements.

[0147] When the optical laminate as a polarizing plate is applied to a liquid crystal display device, the optical laminate may be disposed on the backlight side (rear side) of the liquid crystal cell, on the viewing side, or on both sides. When the optical laminate as a polarizing plate is applied to an organic EL display device, the optical laminate is usually disposed on the viewing side of the organic EL display element. [Example]

[0148] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, "%" and "parts" are by mass % and parts by mass unless otherwise specified.

[0149] [Manufacturing example: polarizer production] A 60 μm-thick polyvinyl alcohol film (average degree of polymerization: approximately 2,400, degree of saponification: 99.9 mol% or more) was immersed in pure water at 30°C, followed by an aqueous solution at 30°C containing iodine, potassium iodide, and water in a mass ratio of 0.02 / 2 / 100. It was then immersed in an aqueous solution at 56.5°C containing potassium iodide, boric acid, and water in a mass ratio of 12 / 5 / 100. The film was then washed with pure water at 8°C and dried at 65°C to obtain a 23 μm-thick polarizer in which iodine was adsorbed and aligned in the polyvinyl alcohol film. Stretching was mainly performed during the iodine dyeing and boric acid treatment steps, with a total stretch ratio of 5.5.

[0150] [Examples 1 to 4, Comparative Examples 1 and 2] (1) Preparation of curable composition Curable compositions (aqueous adhesive solutions) were prepared by mixing the components shown in Table 1 in the amounts shown in Table 1 with pure water as an aqueous solvent. The amount of each component shown in Table 1 is expressed in parts by mass, and is the amount converted into solid content. In Examples 1 to 4 and Comparative Examples 1 and 2, the concentration of the aqueous resin (A) in the obtained curable compositions was 5.0 mass%.

[0151] (2) Preparation of polarizing plates One side of a triacetyl cellulose (TAC) film (Konica Minolta Opto, Inc., trade name "KC4UAW," thickness: 40 μm) was saponified, and the curable composition prepared in (1) above was applied to the saponified surface using a bar coater. One side of a zero-retardation film made of a cyclic polyolefin resin (Zeon Corporation, trade name "ZEONOR," thickness: 23 μm) was corona-treated, and the curable composition prepared in (1) above was applied to the corona-treated surface using a bar coater. The saponified TAC film was laminated on one side of the polarizer, with the curable composition layer facing the polarizer, and the corona-treated zero-retardation film was laminated on the other side, to obtain a laminate having a layer structure of zero-retardation film / curable composition layer / polarizer / curable composition layer / TAC film. This laminate was heated in a hot air dryer at 80°C for 300 seconds to produce a polarizing plate having a layer structure of zero retardation film / cured layer / polarizer / cured layer / TAC film. The thickness of each cured layer in the produced polarizing plate was 20 to 60 nm.

[0152] (3) Evaluation of optical durability The obtained polarizing plate was cut into a size of 30 mm x 30 mm, and then the zero-retardation film side was attached to a glass substrate via a (meth)acrylic adhesive to obtain a measurement sample. The layer structure of the measurement sample was glass substrate / (meth)acrylic adhesive layer / zero-retardation film / cured layer / polarizer / cured layer / TAC film. An alkali-free glass substrate (trade name "Eagle XG" manufactured by Corning Incorporated) was used as the glass substrate. The resulting sample was measured for MD and TD transmittance in the wavelength range of 380 to 780 nm using a spectrophotometer equipped with an integrating sphere (product name "V7100" manufactured by JASCO Corporation), and the degree of polarization at each wavelength was calculated. The calculated degree of polarization was corrected for luminosity using a 2-degree observer (illuminant C) according to JIS Z 8701:1999 "Method of Color Representation - XYZ Color System and X10Y10Z10 Color System," and the luminosity-corrected degree of polarization Py before the durability test was calculated. The measurement sample was placed in the spectrophotometer equipped with an integrating sphere so that the TAC film side of the polarizing plate was the detector side and light was incident from the glass substrate side.

[0153] The degree of polarization (%) is calculated using the following formula: Degree of polarization (λ)=100×(Tp(λ)-Tc(λ)) / (Tp(λ)+Tc(λ)) is defined as: Tp(λ) is the transmittance (%) of the measurement sample measured in a parallel Nicol relationship with linearly polarized light of incident wavelength λ (nm). Tc(λ) is the transmittance (%) of the measurement sample measured in a crossed Nicol relationship with linearly polarized light of incident wavelength λ (nm).

[0154] Next, this measurement sample was placed in a high-temperature, high-humidity environment at a temperature of 85°C and a relative humidity of 85%RH for 500 hours, and then subjected to a durability test in which it was placed in an environment at a temperature of 23°C and a relative humidity of 50%RH for 24 hours. After the durability test, the luminous efficacy-corrected polarization degree Py was determined using the same method as before the durability test. The absolute value (|ΔPy|) of the difference between the luminosity-corrected polarization degree Py after the durability test and the luminosity-corrected polarization degree Py before the durability test was calculated. The calculated values ​​of |ΔPy| are shown in Table 1. The smaller the value of |ΔPy|, the better the optical durability under high-temperature and high-humidity environments. In all of the Examples and Comparative Examples, the difference between the luminosity-corrected polarization degree Py after the durability test and the luminosity-corrected polarization degree Py before the durability test was a negative value.

[0155] (4) Evaluation of adhesion The resulting polarizing plate was attached to a glass substrate with a (meth)acrylic adhesive on the zero-retardation film side to produce a polarizing plate with an adhesive layer. A 25 mm wide, approximately 200 mm long test piece was cut from the resulting polarizing plate with an adhesive layer, and the adhesive layer side of the cut piece was attached to a soda glass. A cutter blade was then inserted between the polarizer and the TAC film, and the film was peeled 30 mm from the edge in the longitudinal direction. The peeled portion was then gripped with the gripping part of a universal tensile tester (Shimadzu Corporation's "AG-1"). The test piece in this state was subjected to a 180° peel test at a gripping speed of 300 mm / min in accordance with JIS K 6854-2:1999 "Adhesives - Test Method for Peel Adhesion Strength - Part 2: 180° Peel" at a temperature of 23°C and a relative humidity of 55%. The adhesion was measured over a 170 mm length excluding the 30 mm around the gripping part. The results are shown in Table 1.

[0156] [Table 1]

[0157] The details of each component shown in Table 1 are as follows: A-1 of the aqueous resin (A): "Epocross WS-300" (trade name, manufactured by Nippon Shokubai Co., Ltd.) [an aqueous solution of an oxazolyl group-containing acrylic polymer having 2-oxazolyl groups as side chains, solid content: 10% by mass, oxazoline value (theoretical value): 130 g solid / eq., oxazolyl group amount (theoretical value): 7.7 mmol / g solid, number average molecular weight: 4 × 10 4 , weight average molecular weight: 12×104)] Aqueous resin (A) A-2: Trade name "GOHSEFIMER Z-200" manufactured by Nippon Synthetic Chemical Industry Co., Ltd. [acetoacetyl-modified polyvinyl alcohol, average polymerization degree: 1100, saponification degree: 98.5 mol% or more] Silane compound (B): Trade name "X-12-1135" manufactured by Shin-Etsu Chemical Co., Ltd. [silane compound having a carboxyl group and a silanol group] Compound (C): Sulfuric acid [Explanation of symbols]

[0158] 10 first thermoplastic resin film, 15 first cured product layer, 20 second thermoplastic resin film, 25 second cured product layer, 30 optical layer, 40 pressure-sensitive adhesive layer.

Claims

1. 1. A curable composition comprising: The ink contains at least an aqueous resin and a silane compound having a silanol group, the aqueous resin contains an oxazolyl group-containing (meth)acrylic resin having an oxazolyl group in the molecule, the silane compound has one or more functional groups selected from the group consisting of an amino group, a carboxyl group, an epoxy group, an acetoacetyl group, a hydroxyalkyl group, a mercapto group, an oxyalkylene group, and an alkenyl group, which may have a substituent, and further contains an Si—O—Si bond; The curable composition further comprises an acid compound.

2. The curable composition according to claim 1 , wherein the content of the acid compound is 5 parts by mass or more and 80 parts by mass or less relative to 100 parts by mass of the oxazolyl group-containing (meth)acrylic resin.

3. 1. A curable composition comprising: The ink contains at least an aqueous resin and a silane compound having a silanol group, the aqueous resin contains a (meth)acrylic resin, the content of the aqueous resin is 30% by mass or more when the solid content concentration of the curable composition is 100% by mass, The curable composition, wherein the silane compound further has an Si—O—Si bond and at least one functional group selected from an amino group and a carboxyl group, which may have a substituent.

4. A cured product layer obtained by curing the curable composition according to any one of claims 1 to 3.

5. an optical layer and a first cured product layer; The optical laminate, wherein the first cured material layer is the cured material layer according to claim 4 .

6. further comprising a first thermoplastic resin film; The optical laminate according to claim 5 , wherein the optical layer, the first cured product layer, and the first thermoplastic resin film are laminated in this order.

7. Further, a second cured material layer and a second thermoplastic resin film are included, The optical laminate according to claim 5 or 6, wherein the second cured product layer and the second thermoplastic resin film are laminated in this order on the side of the optical layer opposite to the first cured product layer side.

8. The optical laminate according to claim 7 , wherein the second cured material layer is the cured material layer according to claim 4 .

9. The optical laminate according to any one of claims 5 to 8, wherein the optical layer is a polarizer.

10. An image display device comprising the optical laminate according to any one of claims 5 to 9 and an image display element.

Images