JP7240938B2 - Optical laminate and image display device - Google Patents

Description

The present invention relates to an optical layered body and an image display device having the same.

In recent years, liquid crystal display devices have been developed for use in mobile devices typified by smartphones and tablet terminals and in-vehicle devices typified by car navigation systems. In such applications, there is a possibility of exposure to harsh environments compared to conventional indoor TV applications.

Durability is also required for optical films constituting liquid crystal display devices and the like. That is, an optical film incorporated in a liquid crystal display device or the like may be placed in a high temperature, high temperature and high humidity environment, or in an environment where high temperature and low temperature are repeated. Also, it is required that the optical characteristics do not deteriorate.

Patent Document 1 describes, as an optical film used in a display device, a polarizing plate comprising a laminate obtained by laminating a polarizer and a protective film via an adhesive composition.

JP 2017-82026 A

An object of the present invention is to provide an optical layered body having good optical durability in a high-temperature and high-humidity environment, and an image display device having the same.

The present invention provides the following optical layered body and image display device.
[1] An optical laminate comprising an optical layer and a cured product layer,
The cured product layer includes a first cured product layer that is a cured product of the polyvinyl acetal resin-containing composition (S),
The polyvinyl acetal resin-containing composition (S) contains a polyvinyl acetal resin (A) and a cross-linking agent (B),
The optical laminate, wherein the cross-linking agent (B) includes a cross-linking agent (B1) that is at least one of an isocyanate-based cross-linking agent and a carbodiimide-based cross-linking agent.
[2] The optical laminate according to [1], wherein the polyvinyl acetal resin (A) has a degree of acetalization of less than 50 mol %.
[3] The content of the cross-linking agent (B1) in the polyvinyl acetal resin-containing composition (S) is The optical laminate according to [1] or [2], which is 10 parts by mass or more and 60 parts by mass or less.
[4] The optical laminate according to any one of [1] to [3], wherein the optical layer, the first cured layer and the first thermoplastic resin film are laminated in this order.
[5] The first thermoplastic resin film is a film containing one or more thermoplastic resins selected from the group consisting of cellulose ester-based resins, polyester-based resins, (meth)acrylic-based resins, and cyclic olefin-based resins. The optical layered product according to [4].
[6] The first thermoplastic resin film is a cellulose ester resin film containing a cellulose ester resin,
The cellulose ester resin film is in direct contact with the first cured material layer,
[4 ] or the optical laminated body as described in [5].
[7] The cured material layer includes a second cured material layer,
According to any one of [1] to [6], wherein the second cured layer and the second thermoplastic resin film are laminated in this order on the side opposite to the first cured layer side of the optical layer. optical laminate.
[8] The second thermoplastic resin film is a film containing one or more thermoplastic resins selected from the group consisting of cellulose ester-based resins, polyester-based resins, (meth)acrylic-based resins, and cyclic olefin-based resins. The optical laminate according to [7].
[9] The optical laminate according to [7] or [8], wherein the second cured product layer is a cured product of the polyvinyl acetal resin-containing composition (S).
[10] The second thermoplastic resin film is a cellulose ester resin film containing a cellulose ester resin,
The cellulose ester resin film is in direct contact with the second cured material layer,
[9 ].
[11] The optical laminate according to any one of [1] to [10], wherein the optical layer is a polarizer.
[12] An image display device comprising the optical layered body according to any one of [1] to [11] and an image display element.

According to the present invention, it is possible to provide an optical layered body having good optical durability in a high-temperature and high-humidity environment, and an image display device having the same.

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

<Optical laminate>
The optical laminate according to the present invention includes an optical layer and a cured product layer, and the cured product layer is a cured polyvinyl acetal resin-containing composition (S) (hereinafter sometimes referred to as "composition (S)"). It includes a first cured product layer that is a product.
The composition (S) is a curable composition and contains a polyvinyl acetal resin (A) and a cross-linking agent (B), wherein the cross-linking agent (B) is at least one of an isocyanate-based cross-linking agent and a carbodiimide-based cross-linking agent. It contains one cross-linking agent (B1).

Since the first cured product layer is the cured product of the composition (S), the optical layered body according to the present invention can exhibit good optical durability in a high-temperature and high-humidity environment.
In addition, the optical layered body according to the present invention exhibits good adhesion between the layers of the optical layered body without performing surface modification treatments such as saponification treatment, plasma treatment, corona treatment, and primer treatment, which will be described later. can do.

[1] Structure of Optical Layered Body FIGS. 1 to 6 show examples of the layer structure of the optical layered body.
The optical laminate shown in FIG. 1 includes an optical layer 30 and a first cured material layer 15 laminated on one surface thereof. The first cured product layer 15 can function as an overcoat layer that covers and protects the surface of the optical layer 30, an optical function layer that additionally imparts an optical function to the optical layer 30, and the like.
The optical layer 30 and the first cured material layer 15 are preferably in direct contact.

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

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

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

The optical layered body shown in FIG. The second cured material layer 25 is included on the other surface. The first cured material layer 15 can function as an adhesive layer that bonds the optical layer 30 and the first thermoplastic resin film 10 together. The second cured layer 25 can function as an overcoat layer that covers and protects the surface of the optical layer 30, an optical function layer that additionally imparts an optical function to the optical layer 30, and the like.
The optical layer 30 and the first cured material layer 15 are preferably in direct contact.
It is preferable that the first cured material layer 15 and the first thermoplastic resin film 10 are in direct contact with each other.
The optical layer 30 and the second cured material layer 25 are preferably in direct contact.

The optical laminate shown in FIG. 6 includes an optical layer 30, a first cured layer 15 laminated on one side thereof, and a second cured layer 25 laminated on the other side of the optical layer 30. include. The first cured layer 15 and the second cured layer 25 function as an overcoat layer that covers and protects the surface of the optical layer 30, an optical function layer that additionally imparts an optical function to the optical layer 30, and the like. can be done.
The optical layer 30 and the first cured material layer 15 are preferably in direct contact.
The optical layer 30 and the second cured material layer 25 are preferably in direct contact.

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

The optical layer 30 may be various optical films (films having optical properties) that can be incorporated in an image display device such as a liquid crystal display device. Examples of the optical 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.

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

[2] Cured Layer The cured layer of the optical layered body according to the present invention may contain the first cured layer 15 and may further contain the second cured layer 25 .

The first cured product layer 15 is a cured product of composition (S), which is a curable composition. The composition (S) comprises a polyvinyl acetal resin (A) and a cross-linking agent (B), wherein the cross-linking agent (B) is at least one of an isocyanate-based cross-linking agent and a carbodiimide-based cross-linking agent (B1). including. Composition (S) can be cured, for example, by heat.

The second cured product layer 25 is not particularly limited as long as it is a cured product of a curable composition, and may be a cured product of the composition (S), or another curable composition different from the composition (S). It may be a cured product of a product. The second cured layer 25 is preferably a cured layer of the composition (S) from the viewpoint of the optical durability of the optical layered body in a high-temperature and high-humidity environment.

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

[2-1] Polyvinyl acetal resin-containing composition (S) (composition (S))
The composition (S) can be used as a coating liquid for forming a coating film (coating layer) on a substrate. For example, a coating film can be formed by coating the composition (S) on a substrate and curing the coating layer. 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 layer composed of a cured composition (S) (FIGS. 1, 4 and 6).

Composition (S) can also be used as an adhesive composition. In one embodiment, the composition (S) is an adhesive composition for bonding the optical layer and the first thermoplastic resin film. In this case, the optical laminate includes an optical layer, a first cured product layer (adhesive layer) composed of a cured product of the composition (S), and a first thermoplastic resin film in this order (Fig. 2 , FIGS. 3 and 5). This optical layered body is obtained by coating the composition (S) on the bonding surface of at least one of the optical layer and the first thermoplastic resin film, and After obtaining a laminate by laminating and, it can be produced by curing the coating layer.

Composition (S) is preferably an aqueous composition. The water-based composition is a solution in which ingredients are dissolved in water or an aqueous solvent containing water as a main component, or a dispersion (e.g., emulsion) in which ingredients are dispersed in water or an aqueous solvent. Having water as the main component means that 50 mass % or more of the total mass of the components forming the solvent is water.

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

The viscosity of the 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 further preferably 2 mPa·sec or more and 20 mPa·sec or less. preferable. If the viscosity at 25° C. exceeds 50 mPa·sec, uniform coating may become difficult and uneven coating may occur, and problems such as clogging of pipes may occur.
The viscosity of the composition (S) at 25°C can be measured with an E-type viscometer.

[2-1-1] Polyvinyl acetal resin (A)
Polyvinyl acetal resin (A) can be obtained by acetalizing polyvinyl alcohol resin with at least one of aldehyde and ketone. Only one type of polyvinyl acetal resin (A) may be used, or two or more types may be used in combination.

Polyvinyl acetal resin (A) usually has acetyl groups and hydroxyl groups in addition to acetal groups. In addition to these functional groups, the polyvinyl acetal resin (A) has an imine structure (-N=CRR' (R and R' each independently represent a hydrogen atom or a hydrocarbon group)), a primary amino group , secondary amino group, amide group (-C (= O) NH-), carboxyl group, sulfonic acid group, sulfinic acid group, sulfenic acid group, phosphoric acid group, phosphonic acid group, functional groups such as thiol groups ( Hereinafter, it may be referred to as a “modified functional group”.). The modified functional group that the polyvinyl acetal resin (A) may have may be introduced by modifying the unmodified polyvinyl acetal resin. It may be introduced by

The polyvinyl alcohol resin used to obtain the polyvinyl acetal resin (A) is not particularly limited, but includes vinyl ester-vinyl alcohol copolymers. The vinyl ester-vinyl alcohol copolymer can be produced by a conventionally known method in which polyvinyl ester is saponified with a basic catalyst or transesterified with alcohol. and vinyl acetate-vinyl alcohol copolymer. The constituent units of the vinyl ester-vinyl alcohol copolymer include an imine structure (-N=CRR' (R and R' have the same meaning as above)), a primary amino group, a secondary amino group, an amide It may have a modified functional group such as a group (-C(=O)NH-), carboxyl group, sulfonic acid group, sulfinic acid group, sulfenic acid group, phosphoric acid group, phosphonic acid group, and the like.

Although the degree of saponification of the polyvinyl alcohol resin is not particularly limited, it is usually 70 mol% or more, preferably 75 mol% or more, more preferably 80 mol% or more, and usually 99.9 mol% or less. Yes, and may be 99.8 mol % or less. The degree of saponification is expressed by the unit ratio (mol%) of the ratio of the acetic acid group contained in the polyvinyl acetate resin, which is the raw material of the polyvinyl alcohol resin, to the hydroxyl group in the saponification process, and is expressed by the following formula:
Saponification degree [mol%] = (number of hydroxyl groups) / (number of hydroxyl groups + number of acetic acid groups) x 100
is a numerical value defined by It can be determined by the method specified in JIS K 6726 (1994).

Aldehydes used to obtain the polyvinyl acetal resin (A) are not particularly limited, but include aldehydes having a chain aliphatic group, a cycloaliphatic group or an aromatic group having 1 to 10 carbon atoms. These aldehydes include, for example, formaldehyde, acetaldehyde, propionaldehyde, n-butyraldehyde, isobutyraldehyde, n-valeraldehyde, n-hexylaldehyde, 2-ethylbutyraldehyde, 2-ethylhexylaldehyde, n-heptylaldehyde, n -aliphatic aldehydes such as octeraldehyde, n-nonylaldehyde, n-decylaldehyde, amylaldehyde; benzaldehyde, cinnamaldehyde, 2-methylbenzaldehyde, 3-methylbenzaldehyde, 4-methylbenzaldehyde, p-hydroxybenzaldehyde, m- aromatic aldehydes such as hydroxybenzaldehyde, phenylacetaldehyde and β-phenylpropionaldehyde; These aldehydes can be used singly or in combination of two or more.

The ketone used to obtain the polyvinyl acetal resin (A) is not particularly limited, but 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, 8'-hydroxy-1'-benzonaphthone and the like.

The aldehyde used to obtain the polyvinyl acetal resin (A) is preferably a resin acetalized with formaldehyde, butyraldehyde, 2-ethylhexylaldehyde, or n-nonylaldehyde, which has excellent acetalization reactivity. Moreover, as the polyvinyl acetal resin (A), a polyvinyl formal resin or a polyvinyl butyral resin is preferable, and a polyvinyl butyral resin is more preferable.

Although the degree of acetalization of the polyvinyl acetal resin (A) is not particularly limited, it is preferably less than 50 mol%, more preferably 45 mol% or less, even more preferably 40 mol% or less. It is 3 mol % or more. When the degree of acetalization is less than 50 mol%, it is easy to obtain an optical layered body exhibiting good optical durability in a high-temperature and high-humidity environment. It is easy to obtain an optical layered body with good adhesion between layers. The degree of acetalization of the polyvinyl acetal resin (A) can be measured using NMR (nuclear magnetic resonance spectrum).

The hydroxyl group content of the polyvinyl acetal resin (A) is preferably 20 mol% or more, more preferably 25 mol% or more, may be 35 mol% or more, and is 90 mol% or less. is preferred. The amount of hydroxyl groups in the polyvinyl acetal resin (A) is the ratio (mol%) of the amount of ethylene groups bonded with hydroxyl groups to the total amount of ethylene groups in the main chain, and the amount of ethylene groups bonded with hydroxyl groups is, for example, , JIS K6728 "Polyvinyl butyral test method".

The acetyl group content of the polyvinyl acetal resin (A) is preferably 0.0001 mol% or more, more preferably 0.001 mol% or more, and may be 0.01 mol% or more. , 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 (A) is calculated by dividing the total amount of ethylene groups in the main chain with respect to the total amount of ethylene groups in the main chain, the amount of ethylene groups in which acetal groups are bonded, and the amount of ethylene groups in which hydroxyl groups are bonded. It is the ratio (mol%) of the ethylene group weight after subtracting the total ethylene group weight. The amount of ethylene groups to which acetal groups are bonded can be calculated, for example, by a method based on JIS K6728 "Polyvinyl butyral test method".

The content of the polyvinyl acetal resin (A) in the composition (S) is preferably 40 parts by mass or more with respect to 100 parts by mass of the total content of the polyvinyl acetal resin (A) and the cross-linking agent (B1). It is more preferably 50 parts by mass or more, more preferably 60 parts by mass or more, preferably 90 parts by mass or less, more preferably 85 parts by mass or less, and 80 parts by mass or less. It is even more preferable to have By setting the content of the polyvinyl acetal resin (A) within the above range, it is possible to obtain an optical laminate having excellent optical durability in a high-temperature and high-humidity environment. It is easy to obtain an optical layered body having good adhesion between the layers of the optical layered body.

[2-1-2] Crosslinking agent (B)
Composition (S) contains a cross-linking agent (B). By including the cross-linking agent (B) in the composition (S), a cross-linked structure is formed in the polyvinyl acetal resin (A) contained in the composition (S), and the composition (S) can be cured. The cross-linking agent (B) is preferably a water-based cross-linking agent when the composition (S) is a water-based composition. In the present specification, the water-based cross-linking agent means a cross-linking agent partially or wholly soluble in water or an aqueous solvent containing water as a main component, or a cross-linking agent partially or wholly dispersed in water or an aqueous solvent containing water as a main component. A cross-linking agent that allows

The cross-linking agent (B) includes a cross-linking agent (B1) that is at least one of an isocyanate-based cross-linking agent and a carbodiimide-based cross-linking agent, and is referred to as a cross-linking agent other than the cross-linking agent (B1) (hereinafter referred to as “another cross-linking agent (B2 )”.) may be included. The cross-linking agent (B1) may contain at least one of an isocyanate cross-linking agent and a carbodiimide cross-linking agent, and may contain both of them. Moreover, the crosslinking agent (B1) may be used alone or in combination of two or more.

The isocyanate-based cross-linking agent that can constitute the cross-linking agent (B1) is a compound having at least two isocyanate groups (--NCO) in the molecule. Specific examples of isocyanate compounds include tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, triphenylmethane triisocyanate and the like. In addition, the isocyanate-based cross-linking agents include adducts obtained by reacting these isocyanate compounds with polyols such as glycerol and trimethylolpropane, and dimers and trimers of isocyanate compounds.

The carbodiimide-based cross-linking agent that can constitute the cross-linking agent (B1) is a compound having at least one carbodiimide group (-N=C=N-) in the molecule. Examples of carbodiimide-based cross-linking agents include monocarbodiimide compounds having one carbodiimide group in the molecule and polycarbodiimide compounds having two or more carbodiimide groups in the molecule. The carbodiimide-based cross-linking agent is preferably a polycarbodiimide compound having two or more carbodiimide groups in the molecule, more preferably a polycarbodiimide compound having an average of 3 to 20 carbodiimide groups per molecule. .

Examples of monocarbodiimide compounds include dicyclohexylcarbodiimide, diisopropylcarbodiimide, dimethylcarbodiimide, diisobutylcarbodiimide, dioctylcarbodiimide, t-butylisopropylcarbodiimide, diphenylcarbodiimide, di-t-butylcarbodiimide, di-β-naphthylcarbodiimide and the like.

The polycarbodiimide compound can be synthesized, for example, by a decarboxylation condensation reaction of a diisocyanate compound in the presence of a carbodiimidation catalyst, and is preferably a polymer. Examples of polycarbodiimide compounds include poly(4,4'-diphenylmethanecarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(diisopropylphenylcarbodiimide), poly(triisopropylphenylcarbodiimide), and the like. aromatic polycarbodiimides; alicyclic polycarbodiimides such as poly(dicyclohexylmethanecarbodiimide); and aliphatic polycarbodiimides such as poly(diisopropylcarbodiimide).

The content of the cross-linking agent (B1) in the composition (S) is preferably 10 parts by mass or more with respect to 100 parts by mass of the total content of the polyvinyl acetal resin (A) and the cross-linking agent (B1). It is more preferably 20 parts by mass or more, more preferably 60 parts by mass or less, more preferably 50 parts by mass or less, and 40 parts by mass or less. is more preferred. By setting the content of the cross-linking agent (B1) within the above range, it is possible to obtain an optical layered body having excellent optical durability in a high-temperature and high-humidity environment. It is easy to obtain an optical layered body having good adhesion between the layers of the layered body.

The content of the cross-linking agent (B1) in the cross-linking agent (B) is preferably 70 parts by mass or more, and preferably 80 parts by mass or more, with respect to 100 parts by mass of the total content of the cross-linking agent (B). It is more preferably 90 parts by mass or more, particularly preferably 95 parts by mass or more, and may be 100 parts by mass.

Examples of the cross-linking agent (B2) other than the cross-linking agent (B1) that may be contained in the cross-linking agent (B) include epoxy-based compounds, aziridine-based compounds, vinylsulfone-based compounds, metal chelate-based compounds, aldehydes, melamine compounds, glyoxal, glyoxal derivatives, water-soluble epoxy resins and the like. Other cross-linking agents (B2) may be used alone or in combination of two or more.

An epoxy-based compound is a compound having at least two epoxy groups in the molecule. Specific examples of epoxy compounds include bisphenol A type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane. Including triglycidyl ether, N,N-diglycidylaniline, N,N,N',N'-tetraglycidyl-m-xylenediamine, 1,3-bis(N,N'-diglycidylaminomethyl)cyclohexane, etc. .

An aziridine-based compound is a compound having at least two 3-membered ring skeletons consisting of one nitrogen atom and two carbon atoms, also called ethyleneimine, in the molecule. Specific examples of aziridine compounds include diphenylmethane-4,4′-bis(1-aziridinecarboxamide), toluene-2,4-bis(1-aziridinecarboxamide), triethylenemelamine, isophthaloylbis-1-(2 -methylaziridine), tris-1-aziridinylphosphine oxide, hexamethylene-1,6-bis(1-aziridinecarboxamide), trimethylolpropane-tris-β-aziridinylpropionate, tetramethylolmethane-tris -β-aziridinyl propionate and the like.

The vinylsulfone-based compound is a compound having a vinylsulfone group, preferably a compound having a plurality of vinylsulfone groups. Specific examples of vinylsulfone compounds include N,N'-trimethylenebis[2-(vinylsulfonyl)acetamide], N,N'-ethylenebis[2-(vinylsulfonyl)acetamide] and the like.

Specific examples of metal chelate compounds include compounds in which polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium are coordinated with acetylacetone or ethyl acetoacetate. including.

The content of the other cross-linking agent (B2) is not particularly limited, but it is preferably 30 parts by mass or less, preferably 20 parts by mass or less, with respect to 100 parts by mass of the total content of the cross-linking agent (B). It is more preferably 10 parts by mass or less, and particularly preferably 5 parts by mass or less.

[2-1-3] Other Components The composition (S) may contain components other than the polyvinyl acetal resin (A) and the cross-linking agent (B). Other components include solvent; resin other than polyvinyl acetal resin (A) (hereinafter sometimes referred to as “other resin”); modified polyvinyl alcohol polymer; coupling agent, tackifier, antioxidant , UV absorbers, heat stabilizers, additives such as hydrolysis inhibitors; solvents and the like.

Solvents include water, organic solvents, or mixtures thereof. The solvent is preferably water or an aqueous solvent containing water as a main component, and the aqueous solvent is preferably a mixture of water and a water-soluble organic solvent. As described above, "mainly containing water" means that 50% by mass or more of the total mass of the components forming the solvent is water. The solvent other than water among the aqueous solvents is not particularly limited as long as it is a solvent that does not undergo layer separation easily in the presence of water, but it is preferably a solvent that dissolves in water, such as methanol, ethanol, isopropyl alcohol, alcohols such as n-propyl alcohol; ketones such as acetone and methyl ethyl ketone; glycols such as ethylene glycol and diethylene glycol; glycol ethers such as N-methylpyrrolidone (NMP), tetrahydrofuran and butyl cellosolve;

Resins other than the polyvinyl acetal resin (A) include (meth) acrylic resins; polyvinyl alcohol resins; ethylene-vinyl alcohol copolymer resins; polyvinylpyrrolidone resins; polyamidoamine resins; epoxy resins; urea-based resins; polyamide-based resins; polyester-based resins; polyurethane-based resins; cellulose-based resins such as methyl cellulose, hydroethyl cellulose and carboxymethyl cellulose; Among these, water-based resins that are soluble or dispersible in water or water-based solvents are preferred. As used herein, "(meth)acryl" represents at least one selected from the group consisting of acryl and methacryl. The same applies to notations such as "(meth)acryloyl" and "(meth)acrylate".

[2-2] Other curable composition The other curable composition that can constitute the second cured layer 25 is not particularly limited, but for example, a curable resin component dissolved or dispersed in water known water-based compositions (including water-based adhesives) and known active-energy-ray-curable compositions containing active-energy-ray-curable compounds (including active-energy-ray-curable adhesives). .

Examples of the resin component contained in the water-based composition include polyvinyl alcohol-based resins and urethane resins.
Water-based compositions containing polyvinyl alcohol resins contain curable components such as polyhydric aldehydes, melamine compounds, zirconia compounds, zinc compounds, glyoxal, glyoxal derivatives, and water-soluble epoxy resins in order to improve adhesion and adhesiveness. or a cross-linking agent.
Water-based compositions containing a urethane resin include water-based compositions containing a polyester-based ionomer-type urethane resin and a compound having a glycidyloxy group. A polyester-based ionomer-type urethane resin is a urethane resin having a polyester skeleton into which a small amount of an ionic component (hydrophilic component) is introduced.

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

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

As the epoxy compound, a hydrogenated epoxy compound (having an alicyclic ring) obtained by reacting an alicyclic polyol obtained by hydrogenating the aromatic ring of an aromatic polyol with epichlorohydrin polyol glycidyl ether); aliphatic epoxy compounds such as polyglycidyl ethers of aliphatic polyhydric alcohols or their alkylene oxide adducts; epoxy compounds having one or more epoxy groups bonded to an alicyclic ring in the molecule Certain alicyclic epoxy compounds and the like can be mentioned.

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

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

[3] Polarizer A polarizer is a layer or film having a function of selectively transmitting linearly polarized light in one direction from natural light.
Examples of the polarizer include a film obtained by adsorbing and aligning a dichroic dye on a polyvinyl alcohol-based resin film. Examples of dichroic dyes include iodine and dichroic organic dyes.
Also, the polarizer may be a coated polarizing film in which a base film is coated with a dichroic dye in the lyotrovic liquid crystal state and then oriented and fixed.
The polarizer described above is called an absorption polarizer because it selectively transmits linearly polarized light in one direction from natural light and absorbs linearly polarized light in another direction.

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

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

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

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

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

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

[4] Retardation film As the retardation film, a stretched film obtained by uniaxially or biaxially stretching a translucent thermoplastic resin; Examples thereof include those in which the above liquid crystal layer is formed on a material film. In this specification, a zero retardation film is also included in the retardation film.
The base film is usually a film made of a thermoplastic resin, and an example of the thermoplastic resin is a cellulose ester resin such as triacetyl cellulose.
Examples of translucent thermoplastic resins include resins that constitute the first thermoplastic resin film 10 described later.

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

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

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

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

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

When the retardation film is a layer (hereinafter sometimes referred to as an "optically anisotropic layer") composed of a polymer in an aligned state of a polymerizable liquid crystal compound, the retardation film may have reverse wavelength dispersion. preferable. The reverse wavelength dispersion is an optical characteristic in which the liquid crystal alignment in-plane retardation value at a short wavelength is smaller than the liquid crystal alignment in-plane retardation value at a long wavelength. (1) and formula (2) are satisfied. Note that Re(λ) represents an in-plane retardation value for light with a wavelength of λnm.
Re(450)/Re(550)≤1 (1)
1≦Re(630)/Re(550) (2)
When the retardation film is in the first form and has reverse wavelength dispersion, it is preferable because coloring during black display on the display device is reduced, and in the formula (1), 0.82 ≤ Re (450) / Re (550 )≦0.93 is more preferable. Furthermore, 120≦Re(550)≦150 is preferable.

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

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

In the second embodiment, the in-plane retardation value Re (550) may be adjusted in the range of 0 to 10 nm, preferably in the range of 0 to 5 nm, and the thickness direction retardation value Rth is -10 to -. It may be adjusted in the range of 300 nm, preferably in the range of -20 to -200 nm.
The thickness-direction retardation value Rth, which means the refractive index anisotropy in the thickness direction, is a retardation value R50 measured by tilting the in-plane fast axis as an inclination axis by 50 degrees and an in-plane retardation value Re. can be calculated from That is, the retardation value Rth in the thickness direction is the in-plane retardation value Re, the retardation value R50 measured by tilting the fast axis by 50 degrees as the tilt axis, the thickness d of the retardation film, and the thickness of the retardation film. From the average refractive index n ₀ , n _x , n _y and n _z are obtained from the following equations (4) to (6) and substituted into equation (3) for calculation.

Rth=[(n _x +n _y )/2−n _z ]×d (3)
Re = (n _x -n _y ) x d (4)
R50=( _nx − _ny′ )×d/cos(φ) (5)
( _nx + _ny + _nz )/3= _n0 (6)
here,
φ=sin ⁻¹ [sin (40°)/n ₀ ]
ny _′ = _ny × _nz /[ _ny2 × ^sin2 (φ ⁾ + _nz2 × ^cos2 ( ^φ )] ^1/2

The retardation film may be a multilayer film having two or more layers. Examples thereof include a retardation film laminated with a protective film on one side or both sides thereof, and a retardation film laminated with two or more retardation films via a pressure-sensitive adhesive or an adhesive.

[5] Thermoplastic resin film The first thermoplastic resin film 10 and the second thermoplastic resin film 20 (hereinafter both are sometimes collectively referred to as "thermoplastic resin films") each have translucency ( (preferably optically transparent) thermoplastic resins, for example, polyolefin resins such as linear polyolefin resins (polypropylene resins, etc.), cyclic polyolefin resins (norbornene resins, etc.); triacetyl cellulose, diacetyl cellulose, etc. Cellulose ester resin; polyester resin such as polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate; polycarbonate resin; (meth)acrylic resin; polystyrene resin; be able to.
The first thermoplastic resin film 10 and the second thermoplastic resin film 20 are each selected from the group consisting of cellulose ester-based resins, polyester-based resins, (meth)acrylic-based resins, and cyclic olefin-based resins. A film containing a plastic resin is preferable, and a cellulose ester resin film containing a cellulose ester resin is more preferable.

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 can each be either unstretched films or uniaxially or biaxially stretched films. The biaxial stretching may be simultaneous biaxial stretching in which the film is simultaneously stretched in two stretching directions, or sequential biaxial stretching in which the film is stretched in a first direction and then in a second direction different from the first direction.
The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may be a protective film that plays a role of protecting the optical layer 30, or a protective film that also has an optical function such as a retardation film. can also
As for the retardation film, the description of [4] above is cited.

From the viewpoint of improving adhesion, the surface of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 to which the composition (S) is applied or the surface to be bonded with the composition (S) is Surface modification treatment such as oxidizing treatment, plasma treatment, corona treatment, and primer treatment may be performed, but surface modification treatment may not be performed. By using the composition (S), even if the surface modification treatment of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is not performed, the first thermoplastic resin film 10 and the composition (S) This is because it is possible to ensure adhesion with the formed first cured material layer 15 and adhesion between the second thermoplastic resin film 20 and the second cured material layer 25 formed of the composition (S). be. Therefore, according to the present invention, the above-described surface modification treatment can be omitted when obtaining the optical layered body, so that the process can be simplified. For the same reason as described above, the bonding surface of the optical layer 30 may or may not be subjected to surface modification treatment.

When the first thermoplastic resin film 10 or the second thermoplastic resin film 20 is a cellulose ester resin film, from the viewpoint of improving adhesion, the surface to which the composition (S) is applied or the composition (S) A saponification treatment may be performed on the bonding surface of. When the composition (S) is used to form the first cured layer 15 and the second cured layer 25, the first thermoplastic resin film 10 and the first cured layer 25 can be formed without saponification. 15 and the adhesion between the second thermoplastic resin film 20 and the second cured material layer 25 can be ensured. The saponification treatment includes a method of immersing in an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide.

In the optical laminate in which the first thermoplastic resin film 10 or the second thermoplastic resin film 20 is a cellulose ester resin film and is in direct contact with the first cured layer 15 and the second cured layer 25, respectively, the cellulose The ester-based resin film has a fluorine element concentration of 2.0 atom % or less when the hydroxyl groups on the surface of the first cured layer 15 side or the second cured layer 25 side are derivatized using a fluorine-based derivatization reagent. may The fluorine element concentration may be 1.8 atom % or less, 1.6 atom % or less, or 1.5 atom % or less. Trifluoroacetic anhydride can be used as the fluorine-based derivatization reagent, and the fluorine element concentration can be measured according to the method described in the Examples.

The concentration of elemental fluorine is considered to indicate the amount of hydroxyl groups on the surface of the cellulose ester resin film. In general, when a cellulose ester resin film is subjected to surface modification treatment, the amount of hydroxyl groups on the surface increases. A cellulose ester-based resin film having a fluorine element concentration within the above range can generally be said to be a cellulose ester-based resin film that has not been subjected to a surface modification treatment or that has been subjected to a low degree of surface modification treatment.

Therefore, in the optical laminate, by forming the first cured material layer 15 and the second cured material layer 25 formed using the composition (S), the surface modification treatment is not performed or the surface modification treatment is performed. Even when the first cured material layer 15 and the second cured material layer 25 are formed so as to be in direct contact with the cellulose ester resin film having a low degree of Good adhesion with the cured material layer 25 can be ensured.

When the second cured material layer 25 is formed using another curable composition instead of the composition (S), on the surface of the second thermoplastic resin film 20 to which the curable composition is applied, From the viewpoint of improving adhesion, it is preferable to perform the surface modification treatment described above. However, from the viewpoint of process simplification, the surface modification treatment may not be performed. The surface modification treatment may be performed on the bonding surface of the optical layer 30 together with the bonding surface of the thermoplastic resin film.
When the second thermoplastic resin film 20 is a cellulose ester resin film, the saponification treatment described above may be performed from the viewpoint of improving adhesion.

Examples of chain polyolefin resins forming the thermoplastic resin film include homopolymers of chain olefins such as polyethylene resins and polypropylene resins, as well as copolymers composed of two or more chain olefins.

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

The cellulose ester-based resin forming the thermoplastic resin film is a resin in which at least a portion of the hydroxyl groups in cellulose is acetic esterified, a portion of which is acetic esterified and a portion of which is esterified with another acid. It may also be a mixed ester. The cellulose ester-based resin is preferably an acetylcellulose-based resin.
Acetyl cellulose resins include triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, and the like.

The polyester-based resin that forms the thermoplastic resin film is a resin other than the cellulose ester-based resin that has an ester bond, and is generally composed of a polycondensate of a polyhydric carboxylic acid or a derivative thereof and a polyhydric alcohol. be.
Polyester-based resins include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polycyclohexanedimethylterephthalate, polycyclohexanedimethylnaphthalate and the like.
Among them, polyethylene terephthalate is preferably used from the viewpoint of mechanical properties, solvent resistance, scratch resistance, cost, and the like. Polyethylene terephthalate refers to a resin in which 80 mol% or more of the repeating units are composed of ethylene terephthalate, and structural units derived from other copolymer components (dicarboxylic acid component such as isophthalic acid; diol component such as propylene glycol, etc.). may contain

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

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

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

Acrylic acid esters include ethyl acrylate, n-, i- or t-butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate and the like. .

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

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

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

As a means for increasing the glass transition temperature of (meth)acrylic resins, it is also effective to introduce a ring structure into the main chain of the polymer. The ring structure is preferably a heterocyclic structure such as a cyclic acid anhydride structure, a cyclic imide structure and a lactone structure. Specific examples include cyclic acid anhydride structures such as glutaric anhydride structure and succinic anhydride structure; cyclic imide structures such as glutarimide structure and succinimide structure; and lactone ring structures such as butyrolactone and valerolactone.
There is a tendency that the larger the content of the ring structure in the main chain, the higher the glass transition temperature of the (meth)acrylic resin.
A cyclic acid anhydride structure and a cyclic imide structure are introduced by copolymerizing monomers having a cyclic structure such as maleic anhydride and maleimide; Method of introduction: It can be introduced by, for example, a method of reacting an amino compound to introduce a cyclic imide structure.
A resin (polymer) having a lactone ring structure is obtained by preparing a polymer having a hydroxyl group and an ester group in the polymer chain, and then heating the hydroxyl group and the ester group in the resulting polymer, if necessary. Accordingly, it can be obtained by a method of forming a lactone ring structure by cyclization condensation in the presence of a catalyst such as an organic phosphorus compound.

The (meth)acrylic resin and the thermoplastic resin film formed therefrom may contain additives as necessary. Examples of additives include lubricants, antiblocking agents, heat stabilizers, antioxidants, antistatic agents, light stabilizers, impact modifiers, surfactants, and the like.
These additives can also be used when other thermoplastic resins than the (meth)acrylic resin are used as the thermoplastic resin constituting the thermoplastic resin film.

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

Examples of the elastic polymer include a crosslinked elastic copolymer having an alkyl acrylate as a main component and copolymerized with another copolymerizable vinyl-based monomer and a crosslinkable monomer.
Examples of the alkyl acrylate, which is the main component of the elastic polymer, include alkyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc., in which the number of carbon atoms in the alkyl group is about 1 to 8. and an alkyl acrylate having an alkyl group having 4 or more carbon atoms is preferably used.

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

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

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

The thermoplastic resin film contains ultraviolet absorbers, infrared absorbers, organic dyes, pigments, inorganic dyes, antioxidants, antistatic agents, surfactants, lubricants, dispersants, heat stabilizers, etc. good too. When the optical laminate is applied to an image display device, a thermoplastic resin film containing an ultraviolet absorber is arranged on the viewing side of an image display element (for example, a liquid crystal cell, an organic EL display element, etc.), so that the image display element Degradation due to ultraviolet rays can be suppressed.
Examples of ultraviolet absorbers include salicylate compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, nickel complex compounds, and the like.

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

The thermoplastic resin film has surface treatments such as a hard coat layer, an antiglare layer, an antireflection layer, a light diffusion layer, an antistatic layer, an antifouling layer, and a conductive layer on its outer surface (surface opposite to the optical layer 30). A layer (coating layer) may be provided.

Each of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 has a thickness of usually 5 μm or more and 200 μm or less, preferably 10 μm or more and 120 μm or less, more preferably 10 μm or more and 85 μm or less, further preferably 15 μm or more and 65 μm or less. is. Each of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 may have a thickness of 50 μm or less, or 40 μm or less. Reducing the thickness of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is advantageous for thinning the optical laminate (polarizing plate) and the image display device including the same.

[6] Manufacture of Optical Laminate An optical laminate having the configuration shown in FIG. By further laminating and bonding the second thermoplastic resin film 20 to the other surface of the optical layer 30 via the second cured material layer 25, an optical laminate having the configuration shown in FIG. 3 can be obtained. can be done.
When manufacturing an optical laminate having both the first thermoplastic resin film 10 and the second thermoplastic resin film 20, these films may be laminated and bonded stepwise one side at a time, or the films on both sides may be laminated and bonded at the same time. Lamination adhesion may be used.

As a method for bonding the optical layer 30 and the first thermoplastic resin film 10, the composition (S) is applied to one or both of the bonding surfaces of the optical layer 30 and the first thermoplastic resin film 10. Then, the other bonding surface is laminated on this, and a bonding roll or the like is used to press from above and below to bond.
Various coating methods such as a doctor blade, wire bar, die coater, comma coater, gravure coater and the like can be used to apply the composition (S). Alternatively, the composition (S) may be cast while continuously supplying the optical layer 30 and the first thermoplastic resin film 10 so that the bonding surfaces of the two are on the inside.

After laminating the optical layer 30 and the first thermoplastic resin film 10, the laminate including the optical layer 30, the first cured layer 15, and the first thermoplastic resin film 10 is subjected to heat treatment. is preferred. The temperature of the heat treatment is, for example, 40° C. or higher and 100° C. or lower, preferably 50° C. or higher and 90° C. or lower. The heat treatment can remove the solvent contained in the curable composition layer. In addition, the heat treatment can promote the curing/crosslinking reaction of the curable composition.

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

When using an active energy ray-curable composition as the curable composition constituting the second cured material layer, after drying the curable composition layer as necessary, the curable composition is irradiated with an active energy ray. Harden the material layer.
The light source used for irradiating the active energy ray may be one that can generate ultraviolet rays, electron beams, X-rays, and the like. In particular, low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, chemical lamps, black light lamps, microwave-excited mercury lamps, metal halide lamps, etc., which have an emission distribution at a wavelength of 400 nm or less, are preferably used.

The optical laminate without the first thermoplastic resin film on the first cured material layer 15 as shown in FIG. 1 is obtained by applying the composition (S) to the surface of the optical layer 30 For example, it can be produced by heat-treating at 80° C. for 300 seconds with 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/composition (S)/optical layer 30, peeling off the separate film, and then performing a heat treatment. can.

The thickness of the first cured layer 15 and the second cured layer 25 formed from the 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 more preferably 20 nm or more and 1 μm or less. A cured product layer formed from the above-described known water-based composition can also have a similar thickness.
The thickness of the cured product layer formed from the active energy ray-curable composition is, for example, 10 nm or more and 20 μm or less, preferably 100 nm or more and 10 μm or less, more preferably 500 nm or more and 5 μm or less.
The first cured layer 15 and the second cured layer 25 may have the same thickness or may have different thicknesses.

[7] Other constituent elements of optical layered body [7-1] Optical functional film A film can be provided, a suitable example of which is a retardation film.
As described above, the first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 can also serve as a retardation film, but a retardation film can also be laminated separately from these films. In the latter case, the retardation film is a first thermoplastic resin film 10, a second thermoplastic resin film 20, a first cured layer 15 and/or a second cured layer 25 via an adhesive layer or an adhesive layer. can be laminated to the outer surface of the As for the retardation film, the description of [4] above is cited.

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

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

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

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

[7-2] Adhesive layer The optical layered body can contain an adhesive layer. Examples of the pressure-sensitive adhesive layer include a pressure-sensitive adhesive layer for bonding the optical laminate to an image display element such as a liquid crystal cell or an organic EL display element, or another optical member. The pressure-sensitive adhesive layer is the outer surface of the optical layer 30 in the optical laminate having the structure shown in FIGS. 1 and 2, and the first thermoplastic resin film 10 or the second thermoplastic The outer surface of the resin film 20, the outer surface of the first cured material layer 15 or the second thermoplastic resin film 20 in the optical laminate having the configuration shown in FIG. It can be laminated on the outer surface of the plastic resin film 10 or the second cured layer 25, or on the outer surface of the first cured layer 15 or the second cured layer 25 in the optical laminate having the configuration shown in FIG.
FIG. 7 shows an example in which an adhesive layer 40 is laminated on the outer surface of the second thermoplastic resin film 20 of the optical layered body having the structure shown in FIG.

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

The formation of the adhesive layer on the optical layered body is carried out by, for example, dissolving or dispersing the adhesive composition in an organic solvent such as toluene or ethyl acetate to prepare an adhesive liquid, which is directly applied to the target surface of the optical layered body. A method in which an adhesive layer is formed by coating, a method in which a sheet-like adhesive layer is formed on a release-treated separate film, and then transferred to the target surface of the optical laminate, etc. It can be done by
The thickness of the pressure-sensitive adhesive layer is determined according to its adhesive strength and the like, and is suitably in the range of 1 µm to 50 µm, preferably 2 µm to 40 µm.

The optical laminate may contain the above separate film. The separate film can be a film made of a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, a polyester resin such as polyethylene terephthalate, or the like. Among them, a stretched film of polyethylene terephthalate is preferable.

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

[7-3] Protective film The optical laminate has a surface (typically, the first thermoplastic resin film 10, the second thermoplastic resin film 20, the first cured layer 15 and/or the second cured layer 25 surface) can be included. The protective film is peeled and removed together with the pressure-sensitive adhesive layer, for example, after the optical layered body is attached to an image display element or other optical member.

The protective film is composed of, for example, a base film and an adhesive layer laminated thereon. As for the pressure-sensitive adhesive layer, the above description is cited.
The resin constituting the base film is, for example, a polyethylene-based resin such as polyethylene, a polypropylene-based resin such as polypropylene, a polyester-based resin such as polyethylene terephthalate or polyethylene naphthalate, or a thermoplastic resin such as a polycarbonate-based resin. be able to. Polyester-based resins such as polyethylene terephthalate are preferred.

<Image display device>
The optical 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 an optical layered body and an image display element. Examples of image display elements include liquid crystal cells and organic EL display elements. Conventionally known devices can be used as these image display devices.

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

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, "%" and "parts" in Examples and Comparative Examples are % by mass and parts by mass.

[Measurement of elemental fluorine concentration]
A sample of 1 cm square was cut out from the target film, and placed in a small vial so as to stand upright. Next, about 150 mg of trifluoroacetic anhydride as a fluorine-based derivatization reagent is added to a weighing bottle with a sliding lid, and the vial (the sample is contained in the bottle) is added to the weighing bottle containing the trifluoroacetic anhydride. ) was put in without a lid. The weighing bottle was sealed with a sliding lid, heated at a temperature of 40° C. for 1 hour, and a triacetyl cellulose (TAC) film not subjected to surface modification treatment (hereinafter sometimes referred to as “unmodified TAC film”). Derivatization of surface hydroxyl groups was performed. After that, the sample in the vial bottle in the weighing bottle was taken out and dried under reduced pressure at a temperature of 40° C. for 1 hour to obtain a measurement sample. For the obtained measurement sample, an X-ray photoelectron spectroscopy (XPS) system (K-Alpha, manufactured by ThermoFisher Scientific, irradiated X-ray: Al Ka (12 kV / 6 mA), 400 μm) was used to measure the derivatized elemental fluorine concentration. It was measured.

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

[Examples 1 to 7, Comparative Examples 1 to 7]
(1) Composition Preparation A composition (aqueous adhesive solution) was prepared by mixing the components shown in Table 1 in the amounts shown in Table 1 together with pure water as an aqueous solvent. The unit of the compounding amount of each component shown in Table 1 is parts by mass, and the compounding amount of each component is the amount in terms of solid content. In Examples 1 to 7 and Comparative Examples 1 to 7, the resin concentration in the obtained compositions was 5% by mass.

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

Regarding the corona-treated surface of the zero-retardation film (cyclic polyolefin resin film) used above, the elemental fluorine concentration was measured by the procedure described above and found to be 1.8 atom %. Further, when the fluorine element concentration of the saponified surface of the saponified TAC film was measured according to the procedure described above, it was 6.1 atom %.

(3) Evaluation of optical durability After cutting the resulting polarizing plate into a size of 30 mm × 30 mm, the zero retardation film side (meth) pasted to the glass substrate via an acrylic adhesive, measurement sample got The layer structure of the measurement sample was glass substrate/(meth)acrylic adhesive layer/zero retardation film/cured layer/polarizer/cured layer/saponified TAC film. A non-alkali glass substrate (trade name “Eagle XG” manufactured by Corning Incorporated) was used as the glass substrate.
For the obtained measurement sample, the MD transmittance and TD transmittance in the wavelength range of 380 to 780 nm were measured using a spectrophotometer with an integrating sphere [manufactured by JASCO Corporation, product name "V7100"]. was calculated. For the calculated degree of polarization, visibility correction was performed using a 2-degree field of view (C light source) of JIS Z 8701: 1999 “Color display method-XYZ color system and X10Y10Z10 color system”, and visibility correction was performed before the durability test. A degree of polarization Py was obtained. The sample to be measured was set in a spectrophotometer with an integrating sphere so that the saponified TAC film side of the polarizing plate was on the detector side and light was incident from the glass substrate side.

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

Next, after placing this measurement sample in a high-temperature and high-humidity environment with a temperature of 85° C. and a relative humidity of 85% RH for 500 hours, it was subjected to a durability test placed in an environment with a temperature of 23° C. and a relative humidity of 50% RH for 24 hours. . After the durability test, the visibility-corrected polarization degree Py was determined by the same method as before the durability test.
The absolute value (|ΔPy|) of the difference between the visibility-corrected polarization degree Py after the durability test and the visibility-corrected polarization degree Py before the durability test was calculated. Table 1 shows the calculated values of |ΔPy|.
The smaller the value of |ΔPy|, the better the optical durability in a high-temperature and high-humidity environment. In any of the examples and comparative examples, the difference between the visibility-corrected polarization degree Py after the durability test and the visibility-corrected polarization degree Py before the durability test showed a negative value.

(4) Evaluation of Adhesion The composition prepared in (1) above was applied to one side of a triacetyl cellulose (TAC) film that had not been subjected to surface modification treatment (hereinafter sometimes referred to as “unmodified TAC film”). The material is coated using a bar coater, an unmodified TAC film is further laminated on the coated composition, and an unmodified TAC film having a layer structure of unmodified TAC film / composition layer / unmodified TAC film A cured laminate was obtained. This uncured laminate is heat-treated at 80° C. for 300 seconds in a hot air dryer to obtain a cured laminate having a layer structure of unmodified TAC film/cured material layer/unmodified TAC film. made. The thickness of the cured product layer in the obtained cured laminate was 20 to 60 nm. The concentration of elemental fluorine on the surface of the unmodified TAC film to be coated with the composition was measured according to the procedure described above and found to be 1.4 atom %.

A test piece having a width of 25 mm and a length of 150 mm was cut out from the obtained cured laminate, and one unmodified TAC film surface was bonded to glass using an acrylic adhesive (thickness: 25 μm). In this state, a tensile tester is used to grasp the length direction end of the test piece (one side of 25 mm in width), JIS K 6854-2: 1999 "Adhesive-Peeling adhesive strength test method-Part 2: 180 A 180 degree peeling test was conducted at a gripping movement speed of 300 mm/min according to the "Peeling". From the resulting force-grip travel distance curve, determine the average peel force over the peel length excluding the first 25 mm grip travel distance, and convert this per 25 mm width (i.e., multiply the average peel force by 1/4 ), and the adhesion of the cured product layer of the above composition to the unmodified TAC film. Table 1 shows the results. "Material failure" in the column of adhesion in Table 1 indicates that the unmodified TAC film was not peeled off and the test piece was broken.

Details of each component shown in Table 1 are as follows.
(resin)
Resins A-1 to A-5 below were used.
A-1: Polyvinyl acetal resin (S-lec KW-10, manufactured by Sekisui Chemical Co., Ltd., degree of acetalization 8 ± 3 mol%)
A-2: Polyvinyl acetal resin (S-lec KW-3, manufactured by Sekisui Chemical Co., Ltd., degree of acetalization 30 ± 3 mol%)
A-3: Acetoacetyl group-modified polyvinyl alcohol (GOSEFIMER Z-200, manufactured by Nippon Synthetic Chemical Industry)
A-4: Low saponified polyvinyl alcohol (GH-23, manufactured by Nippon Synthetic Chemical Industry)
A-5: Low saponified polyvinyl alcohol (KH-17, manufactured by Nippon Synthetic Chemical Industry)
(crosslinking agent)
The following B-1 to B-3 were used as cross-linking agents.
B-1: Isocyanate-based cross-linking agent (water-dispersed hexamethylene diisocyanate (HDI)-based polyisocyanate, Duranate WB40-100, manufactured by Asahi Kasei)
B-2: Polycarbodiimide-based cross-linking agent (Carbodilite V-02-L2, manufactured by Nisshinbo Chemical)
B-3: Cross-linking agent for vinyl sulfone compounds (N,N'-trimethylenebis[2-(vinylsulfonyl)acetamide], VS-C, manufactured by Fujifilm)

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

Claims (12)

An optical laminate comprising an optical layer and a cured product layer,
The cured product layer includes a first cured product layer that is a cured product of the polyvinyl acetal resin-containing composition (S),
The polyvinyl acetal resin-containing composition (S) contains a polyvinyl acetal resin (A) and a cross-linking agent (B),
The cross-linking agent (B) includes a cross-linking agent (B1) that is at least one of an isocyanate-based cross-linking agent and a carbodiimide-based cross-linking agent,
The optical laminate , wherein the polyvinyl acetal resin (A) has a degree of acetalization of less than 50 mol % . The optical laminate according to claim 1, wherein the polyvinyl acetal resin (A) has a degree of acetalization of 3 mol% or more . The content of the cross-linking agent (B1) in the polyvinyl acetal resin-containing composition (S) is 10 parts by mass with respect to 100 parts by mass of the total content of the polyvinyl acetal resin (A) and the cross-linking agent (B1). 3. The optical layered body according to claim 1, wherein the amount is not less than 60 parts by mass and not more than 60 parts by mass. 4. The optical laminate according to claim 1, wherein the optical layer, the first cured material layer, and the first thermoplastic resin film are laminated in this order. The first thermoplastic resin film is a film containing one or more thermoplastic resins selected from the group consisting of cellulose ester-based resins, polyester-based resins, (meth)acrylic-based resins, and cyclic olefin-based resins. Item 5. The optical laminate according to item 4. The first thermoplastic resin film is a cellulose ester resin film containing a cellulose ester resin,
The cellulose ester resin film is in direct contact with the first cured material layer,
The surface of the cellulose ester resin film on the side of the first cured material layer has an elemental fluorine concentration of 2.0 atom % or less when hydroxyl groups on the surface are derivatized using a fluorine-based derivatization reagent. 6. The optical layered body according to 4 or 5. The cured material layer includes a second cured material layer,
7. The second cured product layer and the second thermoplastic resin film are laminated in this order on the side opposite to the first cured product layer side of the optical layer, according to any one of claims 1 to 6. optical laminate. The second thermoplastic resin film is a film containing one or more thermoplastic resins selected from the group consisting of cellulose ester-based resins, polyester-based resins, (meth)acrylic-based resins, and cyclic olefin-based resins. Item 8. The optical laminate according to item 7. 9. The optical laminate according to claim 7, wherein the second cured layer is a cured product of the polyvinyl acetal resin-containing composition (S). The second thermoplastic resin film is a cellulose ester resin film containing a cellulose ester resin,
The cellulose ester resin film is in direct contact with the second cured material layer,
The surface of the cellulose ester resin film on the side of the second cured material layer has an elemental fluorine concentration of 2.0 atom % or less when hydroxyl groups on the surface are derivatized using a fluorine-based derivatization reagent. 9. The optical laminate according to 9. The optical laminate according to any one of claims 1 to 10, wherein the optical layer is a polarizer. An image display device comprising the optical laminate according to any one of claims 1 to 11 and an image display element.

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