Optical laminate, image display device, and method for manufacturing optical laminate

Abstract

Provided is an optical laminate having improved impact resistance and adhesion. The optical laminate includes a retardation film, an anchor layer, and an adhesive sheet. The optical laminate has a structure in which a retardation film, an anchor layer, and an adhesive sheet are laminated in this order. The retardation film contains a polycarbonate-based resin. The anchoring layer comprises a polymer C. The thickness of the anchor layer is from 15 nm to 28 nm (inclusive). The polymer C may contain at least one type selected from the group consisting of polyoxyalkylene group-containing polymers and polyurethane-based polymers.

Description

Technical Field

[0001] The present invention relates to an optical laminate, an image display device, and a method for manufacturing an optical laminate. Background Art

[0002] In recent years, image display devices represented by liquid crystal display devices and electroluminescent (EL) display devices (for example, organic EL display devices, inorganic EL display devices) have been rapidly spreading. The above various image display devices generally have a laminated structure of an image forming layer such as a liquid crystal layer and an EL light emitting layer and an optical laminate, and the optical laminate includes an optical film and an adhesive sheet. The adhesive sheet is mainly used for joining between films contained in the optical laminate and joining between the image forming layer and the optical laminate.

[0003] Patent Document 1 describes a polycarbonate resin laminate including at least a film layer containing a polycarbonate resin (A) and a substrate containing a polycarbonate resin (B) different from the polycarbonate resin (A), the film layer being located on the surface layer, and the film layer containing a polycarbonate resin satisfies given conditions.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-181785 Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] An optical laminate has, for example, an optical film such as a retardation film and an adhesive sheet. In the manufacturing process of an image display device, in order to dispose the optical laminate at a given position, sometimes its side surface is disposed along alignment members such as a rod and a pin. At this time, due to contact with the alignment members, sometimes an adhesive defect occurs at the end of the optical laminate. The adhesive defect sometimes causes poor display of the image display device.

[0009] Therefore, an object of the present invention is to provide an optical laminate having improved impact resistance and adhesion.

[0010] Means for Solving the Problems

[0011] The present invention provides an optical laminate including a retardation film containing a polycarbonate resin, an anchoring layer containing a polymer C, and an adhesive sheet, in the optical laminate, the retardation film, the anchoring layer, and the adhesive sheet are laminated in this order,

[0012] The thickness of the anchoring layer is 15 nm or more and 28 nm or less.

[0013] Furthermore, the present invention provides an image display device including the above-described optical laminate and an image forming layer.

[0014] Furthermore, the present invention provides a method for manufacturing an optical laminate including a retardation film containing a polycarbonate resin, an anchoring layer containing Polymer C, and an adhesive sheet, wherein in the optical laminate, the retardation film, the anchoring layer, and the adhesive sheet are laminated in this order.

[0015] The manufacturing method includes:

[0016] Coating an anchoring layer coating solution containing a solvent S containing an organic solvent and Polymer C on the retardation film to form a coating film having a thickness of T (μm); and

[0017] Drying the coating film,

[0018] In the anchoring layer coating solution, the weight part Wc of Polymer C is 0.01 or more and 0.5 or less with respect to 100 weight parts of the solvent S.

[0019] The converted thickness of the coating film obtained by the following formula (1) is 2 μm or more and 10 μm or less.

[0020] Converted thickness of coating film = T × Wc / 0.1 (1).

[0021] Effects of the Invention

[0022] According to the present invention, an optical laminate with improved impact resistance and adhesion can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 FIG. is a cross-sectional view schematically showing an example of the optical laminate of the present embodiment.

[0024] Figure 2 FIG. is a schematic cross-sectional view showing another example of the optical laminate.

[0025] Figure 3 FIG. is a schematic cross-sectional view showing an example of the image display device of the present embodiment. DETAILED DESCRIPTION

[0026] The optical laminate according to the first aspect of the present invention includes a retardation film containing a polycarbonate resin, an anchoring layer containing Polymer C, and an adhesive sheet, wherein in the optical laminate, the retardation film, the anchoring layer, and the adhesive sheet are laminated in this order.

[0027] The thickness of the anchoring layer is 15 nm or more and 28 nm or less.

[0028] In the second aspect of the present invention, for example, in the optical laminate of the first aspect, the polymer C contains at least one selected from polyoxyalkylene polymers and polyurethane polymers.

[0029] In the third aspect of the present invention, for example, in the optical laminate of the first or second aspect, the thickness of the above-mentioned anchoring layer is 15 nm or more and 23 nm or less.

[0030] In the fourth aspect of the present invention, for example, in the optical laminate of any one of the first to third aspects, the storage modulus of the above-mentioned adhesive sheet at 25°C is 0.05 MPa or more.

[0031] In the fifth aspect of the present invention, for example, in the optical laminate of any one of the first to fourth aspects, the storage modulus of the above-mentioned adhesive sheet at 25°C is 0.15 MPa or more.

[0032] The image display device of the sixth aspect of the present invention includes the optical laminate of any one of the first to fifth aspects and an image forming layer.

[0033] In the manufacturing method of the optical laminate of the seventh aspect of the present invention, the optical laminate includes a retardation film containing a polycarbonate resin, an anchoring layer containing a polymer C, and an adhesive sheet. In the optical laminate, the above-mentioned retardation film, the above-mentioned anchoring layer, and the above-mentioned adhesive sheet are laminated in this order.

[0034] This manufacturing method includes:

[0035] Coating an anchoring layer coating solution containing a solvent S containing an organic solvent and a polymer C on the above-mentioned retardation film to form a coating film with a thickness of T (μm); and

[0036] Drying the above-mentioned coating film.

[0037] In the above-mentioned anchoring layer coating solution, the weight part Wc of the polymer C with respect to 100 weight parts of the solvent S is 0.01 or more and 0.5 or less.

[0038] The converted thickness of the above-mentioned coating film obtained by the following formula (1) is 2 μm or more and 10 μm or less.

[0039] Converted thickness of the coating film = T × Wc / 0.1 (1)

[0040] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the embodiments shown below.

[0041] The optical laminate of the present embodiment includes a retardation film, an anchoring layer, and an adhesive sheet. The optical laminate has a structure in which the retardation film, the anchoring layer, and the adhesive sheet are laminated in this order. The retardation film contains a polycarbonate resin. The anchoring layer contains Polymer C. The thickness of the anchoring layer is 15 nm or more and 28 nm or less.

[0042] The formation of the anchoring layer is a means capable of balancing the prevention of defects of the adhesive sheet and the adhesion. However, the inventors have found through research that when the anchoring layer is laminated on a retardation film containing a polycarbonate resin, a fragile layer is generated on the surface of the retardation film where the anchoring layer is formed. The fragile layer specifically develops when a retardation film containing a polycarbonate resin is used. Although the details are not clear, it is speculated that the organic solvent contained in the coating liquid used for forming the anchoring layer reacts partially with the polycarbonate resin contained in the retardation film or causes it to deteriorate partially, thereby generating the fragile layer. Due to the generation of the fragile layer, the adhesion force, that is, the anchoring force, between the adhesive sheet and the retardation film is reduced. As a result of further research, it has been found that it is preferable to form the anchoring layer with an appropriate thickness in order to prevent defects of the adhesive sheet while mitigating the influence of the fragile layer.

[0043] Figure 1 It is a cross-sectional view schematically showing an example of the optical laminate of the present embodiment. The optical laminate 1A includes a retardation film 2, an anchoring layer 3, and an adhesive sheet 4. The optical laminate 1A has a structure in which the retardation film 2, the anchoring layer 3, and the adhesive sheet 4 are laminated in this order.

[0044] The anchoring layer 3 is formed on the retardation film 2. The anchoring layer 3 is in contact with the retardation film 2. The anchoring layer 3 is formed on one main surface of the retardation film 2. In Figure 1 the anchoring layer 3 is formed over the entire one main surface of the retardation film 2. However, it should be noted that the anchoring layer 3 may be formed only on a part of one main surface of the retardation film 2. In the present specification, the "main surface" is the surface of the film or layer having the widest area.

[0045] The adhesive sheet 4 is formed in contact with the anchoring layer 3. The adhesive sheet 4 is formed on one main surface of the anchoring layer 3. Specifically, the adhesive sheet 4 is formed on the main surface of the anchoring layer 3 where the retardation film 2 is not formed. In Figure 1 the adhesive sheet 4 is formed over the entire one main surface of the anchoring layer 3. However, it should be noted that the adhesive sheet 4 may be formed only on a part of one main surface of the anchoring layer 3.

[0046] The adhesive sheet is formed of, for example, the adhesive composition (I). Hereinafter, the details of the adhesive composition (I) will be described.

[0047] [Adhesive Composition (I)]

[0048] Examples of the adhesive that constitutes the adhesive sheet include acrylic adhesives, rubber adhesives, vinyl alkyl ether adhesives, silicone adhesives, polyester adhesives, polyamide adhesives, urethane adhesives, fluorine adhesives, epoxy adhesives, polyether adhesives, and the like. It should be noted that the adhesive that constitutes the adhesive sheet can be used alone or in combination of two or more. However, from the viewpoints of transparency, processability, durability, adhesion, etc., it is preferable to use an acrylic adhesive (composition) containing a (meth)acrylic polymer alone. In other words, the adhesive sheet preferably contains a (meth)acrylic polymer. In the present specification, "(meth)acrylic acid" means acrylic acid and methacrylic acid. In addition, "(meth)acrylate" means acrylate and methacrylate.

[0049] [(meth)acrylic polymer (A)]

[0050] (Meth)acrylic polymer (A) may have a structural unit derived from a (meth)acrylic monomer having an alkyl group with 1 to 30 carbon atoms in the side chain as a main unit. The alkyl group may be linear or may have a branched chain. (Meth)acrylic polymer (A) may have one or more structural units derived from (meth)acrylic monomer (A1). Examples of (meth)acrylic monomer (A1) are methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, isobutyl (meth)acrylate, n-pentyl (meth)acrylate, isopentyl (meth)acrylate, n-hexyl (meth)acrylate, isohexyl (meth)acrylate, isoheptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl (meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, n-dodecyl (meth)acrylate (lauryl (meth)acrylate), n-tridecyl (meth)acrylate, and n-tetradecyl (meth)acrylate. In the present specification, "main unit" means a unit that occupies, for example, 50% by weight or more, preferably 60% by weight or more, more preferably 70% by weight or more, particularly preferably 80% by weight or more, and further preferably 90% by weight or more of all the structural units possessed by the polymer.

[0051] (Meth)acrylic polymer (A) may have a structural unit derived from a (meth)acrylic monomer (A1) whose glass transition temperature (Tg) is in the range of -70 to -20°C when formed into a homopolymer. Examples of this monomer (A1) are n-butyl acrylate.

[0052] (Meth)acrylic polymer (A) may also have structural units other than those derived from (meth)acrylic monomer (A1). Such structural units are derived from monomers (A2) capable of copolymerizing with (meth)acrylic monomer (A1). (Meth)acrylic polymer (A) may have one or more than two of such structural units.

[0053] Examples of monomer (A2) are aromatic ring-containing monomers. The aromatic ring-containing monomer may be an aromatic ring-containing (meth)acrylic monomer. Examples of the aromatic ring-containing monomer are phenyl (meth)acrylate, phenoxyethyl (meth)acrylate, benzyl (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, ethylene oxide-modified nonylphenol (meth)acrylate, hydroxyethylated β-naphthol (meth)acrylate, and biphenyl (meth)acrylate. The content rate of the structural units derived from the aromatic ring-containing monomer in (meth)acrylic polymer (A) is, for example, 0 to 50% by weight, may be 1 to 30% by weight, 5 to 25% by weight, and further may be 8 to 20% by weight. If the blending amount of crosslinking agent (B) in the adhesive composition (I) increases, sometimes a self-polymer of crosslinking agent (B) is formed. When (meth)acrylic polymer (A) has structural units derived from the aromatic ring-containing monomer, the compatibility of (meth)acrylic polymer (A) with crosslinking agent (B) and its self-polymer can be improved. The improvement of the compatibility can contribute to the improvement of the uniformity of the adhesive sheet by suppressing, for example, the precipitation of the self-polymer.

[0054] Other examples of monomer (A2) are hydroxy group-containing monomers. The hydroxy group-containing monomer may be a hydroxy group-containing (meth)acrylic monomer. Examples of the hydroxy group-containing monomer are hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate, and methyl (4-hydroxymethylcyclohexyl) acrylate. It should be noted that the hydroxy group can react with various crosslinking agents. From the viewpoint of improving the uniformity of the formed crosslinked structure, the content rate of the structural units derived from the hydroxy group-containing monomer in (meth)acrylic polymer (A) may be 1% by weight or less, may be 0.5% by weight or less, further may be 0.1% by weight or less, and may also be 0% by weight (the structural unit may not be included).

[0055] The monomer (A2) can be a carboxyl group-containing monomer, an amino group-containing monomer, or an amide group-containing monomer. Examples of the carboxyl group-containing monomer include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid. Examples of the amino group-containing monomer include N,N-dimethylaminoethyl (meth)acrylate and N,N-dimethylaminopropyl (meth)acrylate. Examples of the amide group-containing monomer include acrylamide monomers such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropylacrylamide, N-methyl(meth)acrylamide, N-butyl(meth)acrylamide, N-hexyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, N-hydroxymethyl-N-propyl(meth)acrylamide, aminomethyl(meth)acrylamide, aminoethyl(meth)acrylamide, mercaptomethyl(meth)acrylamide, and mercaptoethyl(meth)acrylamide; N-acryloyl heterocyclic monomers such as N-(meth)acryloylmorpholine, N-(meth)acryloylpiperidine, and N-(meth)acryloylpyrrolidine; and N-vinyl lactam monomers containing N-vinyl such as N-vinylpyrrolidone and N-vinyl-ε-caprolactam. By making the (meth)acrylic polymer (A) have a structural unit derived from a carboxyl group-containing monomer, particularly from acrylic acid, for example, the self-polymerization property of the crosslinking agent (B) can be improved. The improvement of the self-polymerization property of the crosslinking agent (B) can particularly contribute to the suppression of the peeling of the adhesive sheet in a humid environment and the stabilization of the physical properties of the adhesive sheet in a system with a high content of the crosslinking agent (B).

[0056] The monomer (A2) can be a polyfunctional monomer. Examples of the polyfunctional monomer include polyfunctional acrylates such as hexanediol di(meth)acrylate (1,6-hexanediol di(meth)acrylate), butanediol di(meth)acrylate, (poly)ethylene glycol di(meth)acrylate, (poly)propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol hexa(meth)acrylate, trimethylolpropane tri(meth)acrylate, tetramethylolmethane tri(meth)acrylate, allyl (meth)acrylate, vinyl (meth)acrylate, epoxy acrylate, polyester acrylate, and urethane acrylate; and divinylbenzene. The polyfunctional acrylate is preferably 1,6-hexanediol diacrylate and dipentaerythritol hexa(meth)acrylate.

[0057] The total content ratio of structural units derived from carboxyl group-containing monomers, amino group-containing monomers, amide group-containing monomers, and polyfunctional monomers in the (meth)acrylic polymer (A) is preferably 20% by weight or less, more preferably 10% by weight or less, and still more preferably 8% by weight or less. When the (meth)acrylic polymer (A) has such structural units, the total content ratio is, for example, 0.01% by weight or more, and may also be 0.05% by weight or more. The (meth)acrylic polymer (A) may not contain structural units derived from polyfunctional monomers.

[0058] Examples of the other monomer (A2) include (meth)acrylic acid alkoxyalkyl esters such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, methoxytriethylene glycol (meth)acrylate, 3-methoxypropyl (meth)acrylate, 3-ethoxypropyl (meth)acrylate, 4-methoxybutyl (meth)acrylate, and 4-ethoxybutyl (meth)acrylate; epoxy group-containing monomers such as glycidyl (meth)acrylate and methyl glycidyl (meth)acrylate; sulfonic acid group-containing monomers such as sodium vinylsulfonate; phosphoric acid group-containing monomers; (meth)acrylic acid esters having an alicyclic hydrocarbon group such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, and isobornyl (meth)acrylate; vinyl esters such as vinyl acetate and vinyl propionate; aromatic vinyl compounds such as styrene and vinyltoluene; olefins or diolefins such as ethylene, propylene, butadiene, isoprene, and isobutene; vinyl ethers such as vinyl alkyl ethers; and vinyl chloride.

[0059] The total content ratio of structural units derived from the above other monomer (A2) in the (meth)acrylic polymer (A) is, for example, 30% by weight or less, may also be 10% by weight or less, and may also be 0% by weight (excluding such structural units).

[0060] The (meth)acrylic polymer (A) can be formed by polymerizing one or more of the above monomers using a known method. It is also possible to polymerize a monomer and a partial polymer of the monomer. The polymerization can be carried out, for example, by solution polymerization, emulsion polymerization, bulk polymerization, thermal polymerization, or active energy ray polymerization. Since an adhesive sheet having excellent optical transparency can be formed, solution polymerization and active energy ray polymerization are preferred. It is preferable to carry out the polymerization while avoiding contact of the monomer and / or the partial polymer with oxygen. For this purpose, for example, polymerization in an inert gas atmosphere such as nitrogen or polymerization in a state where oxygen is blocked by a resin film or the like can be employed. The (meth)acrylic polymer (A) to be formed can be in any form such as a random copolymer, a block copolymer, or a graft copolymer.

[0061] The polymerization system for forming the (meth)acrylic polymer (A) may contain one or more polymerization initiators. The type of polymerization initiator can be selected according to the polymerization reaction, for example, it can be a thermal polymerization initiator or a photo-polymerization initiator.

[0062] Solvents used in solution polymerization are, for example, esters such as ethyl acetate and n-butyl acetate; aromatic hydrocarbons such as toluene and benzene; aliphatic hydrocarbons such as n-hexane and n-heptane; cycloaliphatic hydrocarbons such as cyclohexane and methylcyclohexane; ketones such as methyl ethyl ketone and methyl isobutyl ketone. However, the solvents are not limited to the above examples. The solvent can be a mixed solvent of two or more solvents.

[0063] Polymerization initiators used in solution polymerization are, for example, azo polymerization initiators, peroxide polymerization initiators, and redox polymerization initiators. Examples of peroxide polymerization initiators are benzoyl peroxide and tert-butyl peroxymaleate. Among them, azo polymerization initiators disclosed in JP-A-2002-69411 are preferably used. Examples of such azo polymerization initiators are 2,2'-azobisisobutyronitrile (AIBN), 2,2'-azobis(2-methylbutyronitrile), dimethyl 2,2'-azobis(2-methylpropionate), and 4,4'-azobis(4-cyanovaleric acid). However, the polymerization initiators are not limited to the above examples. With respect to 100 parts by weight of the total amount of the monomers, the amount of the azo polymerization initiator is, for example, 0.05 to 0.5 part by weight, and can also be 0.1 to 0.3 part by weight.

[0064] Actinic energy rays used in actinic energy ray polymerization are, for example, ionizing rays such as α-rays, β-rays, γ-rays, neutron rays, and electron rays, and ultraviolet rays. The actinic energy rays are preferably ultraviolet rays. Polymerization by irradiation with ultraviolet rays is also called photo-polymerization. The polymerization system of actinic energy ray polymerization typically contains a photo-polymerization initiator. The polymerization conditions for actinic energy polymerization are not limited as long as the (meth)acrylic polymer (A) can be formed.

[0065] Photo-polymerization initiators are, for example, benzoin ether photo-polymerization initiators, acetophenone photo-polymerization initiators, α-hydroxyketone photo-polymerization initiators, aromatic sulfonyl chloride photo-polymerization initiators, photoactive oxime photo-polymerization initiators, benzoin photo-polymerization initiators, benzil photo-polymerization initiators, benzophenone photo-polymerization initiators, ketal photo-polymerization initiators, and thioxanthone photo-polymerization initiators. However, the photo-polymerization initiators are not limited to the above examples.

[0066] Benzoin ether photoinitiators such as benzoin methyl ether, benzoin ethyl ether, benzoin propyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 2,2-dimethoxy-1,2-diphenylethane-1-one, anisole methyl ether. Acetophenone photoinitiators such as 2,2-diethoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 1-hydroxycyclohexyl phenyl ketone, 4-phenoxydichloroacetophenone, 4-(tert-butyl)dichloroacetophenone. α-Hydroxy ketone photoinitiators such as 2-methyl-2-hydroxyacetophenone, 1-[4-(2-hydroxyethyl)phenyl]-2-methylpropan-1-one. Aromatic sulfonyl chloride photoinitiators such as 2-naphthalenesulfonyl chloride. Photoactive oxime photoinitiators such as 1-phenyl-1,1-propanedione-2-(O-ethoxycarbonyl oxime). Benzoin photoinitiators such as benzoin. Benzil photoinitiators such as benzil. Benzophenone photoinitiators such as benzophenone, benzoyl benzoic acid, 3,3'-dimethyl-4-methoxybenzophenone, polyvinyl benzophenone, α-hydroxycyclohexyl phenyl ketone. Ketal photoinitiators such as benzil dimethyl ketal. Thioxanthone photoinitiators such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-diisopropylthioxanthone, dodecylthioxanthone.

[0067] With respect to 100 parts by weight of the total amount of the monomers, the amount of the photoinitiator is, for example, 0.01 to 1 part by weight, and may also be 0.05 to 0.5 part by weight.

[0068] The weight-average molecular weight (Mw) of the (meth)acrylic polymer (A) is, for example, 1 million to 2.8 million, and from the viewpoints of the durability and heat resistance of the adhesive sheet, it may be 1.2 million or more, and further may be 1.4 million or more. The weight-average molecular weight (Mw) of the polymers and oligomers in this specification is a value obtained based on the measurement by GPC (gel permeation chromatography) (in terms of polystyrene conversion).

[0069] The content ratio of the (meth)acrylic polymer (A) in the adhesive composition (I) is, for example, 50% by weight or more in terms of solid content ratio, and may be 60% by weight or more, 70% by weight or more, 80% by weight or more, and further may be 85% by weight or more. The upper limit value of the content ratio is, for example, 99.5% by weight, and may be 99% by weight, 97% by weight, 95% by weight, 93% by weight, and further may be 90% by weight.

[0070] [Crosslinking agent (B)]

[0071] The crosslinking agent (B) is typically a polyfunctional crosslinking agent having two or more crosslinking reaction groups per molecule. The crosslinking agent (B) may also be a crosslinking agent having three or more crosslinking reaction groups per molecule, i.e., a crosslinking agent having trifunctionality or higher. The upper limit of the number of crosslinking reaction groups per molecule is, for example, 5.

[0072] The crosslinking agent (B) is, for example, an isocyanate crosslinking agent. The isocyanate crosslinking agent contains an isocyanate group as a crosslinking reaction group. The crosslinking agent (B) of the isocyanate type may be an aromatic isocyanate compound, an alicyclic isocyanate compound, or an aliphatic isocyanate compound. The isocyanate crosslinking agent (especially a trifunctional isocyanate crosslinking agent) is preferred in terms of durability.

[0073] Examples of the aromatic isocyanate compound that can be used as the crosslinking agent (B) are phthalic diisocyanate, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-biphenyl diisocyanate (4,4'-diphenyl diisocyanate), 1,5-naphthalene diisocyanate, and xylylene diisocyanate.

[0074] Examples of the alicyclic isocyanate compound that can be used as the crosslinking agent (B) are 1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated toluene diisocyanate, and hydrogenated tetramethylxylylene diisocyanate.

[0075] Examples of the aliphatic isocyanate compound that can be used as the crosslinking agent (B) are trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate.

[0076] The crosslinking agent (B) may also be a derivative of the above isocyanate compound. Examples of the derivative are polymers (dimers, trimers, pentamers, etc.), adducts (addition products) obtained by addition with a polyol such as trimethylolpropane, urea-modified products, biuret-modified products, urethane-modified products, isocyanurate-modified products, carbodiimide-modified products, and urethane prepolymers obtained by addition with a polyether polyol, polyester polyol, acrylic polyol, polybutadiene polyol, polyisoprene polyol, etc.

[0077] The crosslinking agent (B) is preferably an aromatic isocyanate compound and its derivatives, more preferably toluene diisocyanate and its derivatives (in other words, more preferably toluene diisocyanate-based (TDI-based) crosslinking agents). Compared with xylylene diisocyanate and its derivatives (in other words, xylylene diisocyanate-based (XDI-based) crosslinking agents), the TDI-based crosslinking agents have excellent reaction uniformity. Examples of the TDI-based crosslinking agents are adducts of toluene diisocyanate and polyfunctional alcohols, and more specific examples are trimethylolpropane / toluene diisocyanate trimer adducts.

[0078] Commercially available products can be used as the crosslinking agent (B). Examples of the commercially available products are Millionate MT, Millionate MTL, Millionate MR-200, Millionate MR-400, Coronate L, Coronate HL, and Coronate HX (all manufactured by Tosoh Corporation; all are trade names), and Takenate D-101E, Takenate D-102, Takenate D-103, Takenate D-110N, Takenate D-120N, Takenate D-140N, Takenate D-160N, Takenate D-165N, Takenate D-170HN, Takenate D-178N, Takenate 500, and Takenate 600 (all manufactured by Mitsui Chemicals, Inc.; all are trade names). The crosslinking agent (B) can preferably be Takenate D-101E.

[0079] As the isocyanate-based crosslinking agent, one of the above-mentioned isocyanate-based crosslinking agents can be used alone, or two or more thereof can be used in combination. With respect to 100 parts by weight of the (meth)acrylic polymer (A), the blending amount of the isocyanate-based crosslinking agent in the adhesive composition (I) can be, for example, 0.1 part by weight or more, 0.2 part by weight or more, 0.3 part by weight or more, 0.5 part by weight or more, 0.6 part by weight or more, 1 part by weight or more, 2 part by weight or more, and further can be 2.3 part by weight or more. The upper limit of the blending amount is, for example, 30 parts by weight or less, and can be 28 parts by weight or less, 25 parts by weight or less, 20 parts by weight or less, 15 parts by weight or less, 10 parts by weight or less, 8 parts by weight or less, 5 parts by weight or less, 4 parts by weight or less, and further can be 3 parts by weight or less.

[0080] The adhesive composition (I) may also contain a crosslinking agent other than the isocyanate crosslinking agent. Examples of the crosslinking agent other than the isocyanate crosslinking agent are peroxide crosslinking agents, epoxy crosslinking agents, imine crosslinking agents, and polyfunctional metal chelates. With respect to 100 parts by weight of the (meth)acrylic polymer (A), the compounding amount of the crosslinking agent other than the isocyanate crosslinking agent may be, for example, 2 parts by weight or less, 1 part by weight or less, 0.5 part by weight or less, 0.3 part by weight or less, 0.28 part by weight or less, 0.25 part by weight or less, 0.2 part by weight or less, and further may be 0.15 part by weight or less. The lower limit value of the compounding amount is, for example, 0 part by weight. The crosslinking agent (B) may contain an isocyanate crosslinking agent and a peroxide crosslinking agent. From the viewpoint of the durability of the adhesive sheet, the adhesive composition (I) may substantially not contain other crosslinking agents, particularly epoxy crosslinking agents.

[0081] [Additives]

[0082] Other additives may also be contained in the adhesive composition (I). Examples of the additives are silane coupling agents, polyfunctional alcohols, coloring agents such as pigments and dyes, surfactants, plasticizers, tackifiers, surface lubricants, leveling agents, rework improvers, softeners, antioxidants, anti-aging agents, light stabilizers, ultraviolet absorbers, polymerization inhibitors, antistatic agents (alkali metal salts, ionic liquids, ionic solids, etc. as ionic compounds), inorganic fillers, organic fillers, powders such as metal powders, particles, and foils. With respect to 100 parts by weight of the (meth)acrylic polymer (A), the additives may be compounded, for example, in the range of 10 parts by weight or less, preferably 5 parts by weight or less, and more preferably 1.5 parts by weight or less.

[0083] Examples of the silane coupling agents are epoxy group-containing silane coupling agents such as 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; amino group-containing silane coupling agents such as 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxysilyl-N-(1,3-dimethylbutyl)propylamine, and N-phenyl-γ-aminopropyltrimethoxysilane; (meth)acryloyl group-containing silane coupling agents such as 3-acryloxypropyltrimethoxysilane and 3-methacryloxypropyltriethoxysilane; and isocyanate group-containing silane coupling agents such as 3-isocyanatopropyltriethoxysilane.

[0084] When the adhesive composition (I) contains a silane coupling agent, its blending amount is, for example, 5 parts by weight or less, and may be 3 parts by weight or less, 1 part by weight or less, 0.5 part by weight or less, 0.2 part by weight or less, 0.1 part by weight or less, and further may be 0.05 part by weight or less, based on 100 parts by weight of the (meth)acrylic polymer (A). The adhesive composition (I) may also contain no silane coupling agent.

[0085] The adhesive composition (I) may contain a polyhydric alcohol. The molecular weight of the polyhydric alcohol is, for example, 240 or less, and may be 230 or less, 220 or less, 210 or less, 200 or less, 190 or less, 180 or less, 170 or less, 160 or less, and further may be 150 or less. The lower limit of the molecular weight is, for example, 60 or more, and may be 80 or more, 90 or more, and further may be 100 or more.

[0086] Examples of the polyhydric alcohol are alkylene glycols such as ethylene glycol and propylene glycol and their polymers; ether diols such as diethylene glycol and their polymers; trimethylolethane; trimethylolpropane; glycerin; and sugar alcohols such as pentaerythritol and sorbitol. The polyhydric alcohol is preferably trimethylolpropane, glycerin, and diethylene glycol and their polymers, and more preferably trimethylolpropane.

[0087] The polyhydric alcohol may also have 3 or more functional groups. Examples of the 3-functional polyhydric alcohol are trimethylolpropane and glycerin.

[0088] The polyhydric alcohol may not have a reactive group reactive with the crosslinking agent (B) other than the hydroxyl group. The reactive group is, for example, at least one selected from an amino group, a carboxyl group, and an epoxy group, and particularly an amino group.

[0089] The blending amount of the polyhydric alcohol in the adhesive composition (I) is, for example, 0.5 part by weight or more and 20 parts by weight or less, based on 100 parts by weight of the (meth)acrylic polymer (A). The upper limit of the blending amount may be 15 parts by weight or less, 10 parts by weight or less, 8 parts by weight or less, 5 parts by weight or less, 4 parts by weight or less, and further may be 3 parts by weight or less.

[0090] The adhesive composition (I) may also not contain a crosslinking accelerator such as a catalyst. An example of the crosslinking accelerator is a polyether, a polyether polyol, or a phosphate ester having a reactive group reactive with the crosslinking agent (B). The reactive group is, for example, at least one selected from a hydroxyl group, an amino group, a carboxyl group, and an epoxy group, and particularly a hydroxyl group or an amino group. The adhesive composition (I) may not contain a polyether polyol having an amino group, and may not contain a phosphate ester having a hydroxyl group.

[0091] The type of the adhesive composition (I) is, for example, an emulsion type, a solvent type (solution type), an active energy ray-curable type (photo-curable type), or a hot melt type (hot melt). From the viewpoint of being able to form an adhesive sheet with more excellent durability, the adhesive composition (I) can be a solvent type. The solvent-type adhesive composition (I) may not contain a photo-curing agent such as an ultraviolet curing agent.

[0092] [Method for manufacturing an adhesive sheet]

[0093] The adhesive sheet 4 is formed from the adhesive composition (I). The adhesive sheet 4 contains, for example, a crosslinked product of a (meth)acrylic polymer (A). The adhesive sheet 4 can be formed from the adhesive composition (I) by the following method.

[0094] The method for manufacturing the adhesive sheet 4 includes, for example: coating the adhesive composition (I) containing the (meth)acrylic polymer (A) and a crosslinking agent on a substrate to form a coating film; and drying the obtained coating film.

[0095] As the substrate, for example, a release film can be used. The adhesive sheet 4 formed on the release film can be transferred to, for example, an optical film. The substrate can be an optical film. In this case, a first adhesive sheet can be formed on the optical film, and thus an optical film with a first adhesive sheet can be obtained.

[0096] The release film can be used as a separator until the adhesive sheet 4 is actually used after transferring the adhesive sheet 4 to the anchoring layer 3, thereby simplifying the process.

[0097] As the constituent material of the release film, for example, the following can be cited: plastic films, papers, cloths, porous materials such as non-woven fabrics, nets, foamed sheets, metal foils, and appropriate thin sheet materials such as laminates thereof. From the aspect of excellent surface smoothness, a plastic film is preferably used.

[0098] There is no particular limitation on the plastic film. For example, the following can be cited: polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, ethylene-vinyl acetate copolymer film, etc.

[0099] The thickness of the release film is usually 5 to 200 μm, preferably about 5 to 100 μm. The release film may be subjected to a release treatment such as a silicone type, a fluorine type, or a long-chain alkyl type. The release film may also be subjected to a release and antifouling treatment using a release agent such as fatty acid amides and silica powder, and an antistatic treatment such as a coating type, a mixing type, or an evaporation deposition type.

[0100] A solution (adhesive solution) containing the adhesive composition (I) can also be applied to the substrate. The solid content concentration of the adhesive solution is, for example, 5 to 50% by weight, preferably 10 to 40% by weight. It should be noted that the adhesive solution can be prepared by appropriately adding the same solvent or a different solvent as the polymerization solvent to the adhesive composition (I) according to the polymerization method of the (meth)acrylic polymer (A).

[0101] As a method for applying the adhesive composition (I) to the substrate, various methods can be used, for example, roll coating method, roll kiss coating method, gravure coating method, reverse coating method, roll brush method, spraying method, dip roll coating method, bar coating method, knife coating method, air knife coating method, curtain coating method, die lip coating method, extrusion coating method using a die coater, etc. The coating amount of the adhesive composition (I) can be appropriately adjusted according to the thickness of the target adhesive sheet 4.

[0102] By drying the coating film, the coating film is cured to form the adhesive sheet 4. The drying temperature of the coating film is not particularly limited, for example, it is 130°C or lower, preferably 125°C or lower, more preferably 120°C or lower, further preferably 110°C or lower, and particularly preferably 100°C or lower. The drying temperature of the coating film can be 60°C or higher, or can be 80°C or higher. When the drying temperature is 60°C or higher, for example, the reaction of the isocyanate crosslinking agent proceeds smoothly, the cohesion of the adhesive sheet 4 can be improved, and the tendency of display unevenness of the image display device can be reduced. When the drying temperature is 130°C or lower, for example, the reaction rate of the isocyanate crosslinking agent can be appropriately adjusted, and the transparency can be ensured.

[0103] The drying time of the coating film can be appropriately adjusted according to the composition of the adhesive composition (I), preferably 30 seconds to 300 seconds, more preferably 40 seconds to 240 seconds, and particularly preferably 60 seconds to 180 seconds.

[0104] The thickness of the adhesive sheet 4 is not particularly limited, and can be 2 to 150 μm, or can be 2 to 100 μm, or can also be 5 to 50 μm. By appropriately adjusting the thickness of the adhesive sheet 4, the adhesion between the retardation film 2 and the adhesive sheet 4 can be improved. In addition, by appropriately adjusting the thickness of the adhesive sheet 4, the peeling of the adhesive sheet 4 from adherends such as glass and image display devices can be suppressed.

[0105] The storage modulus G’ of the adhesive sheet 4 at 25°C can be 0.05 MPa or more, or can be 0.08 MPa or more, 0.10 MPa or more, 0.12 MPa or more, 0.13 MPa or more, and further can be 0.15 MPa or more. The upper limit value of the storage modulus G’ of the adhesive sheet 4 at 25°C can be 5 MPa or less, 4 MPa or less, 3 MPa or less, 2 MPa or less, 1 MPa or less, 0.5 MPa or less, 0.3 MPa or less, 0.25 MPa, and further can be 0.20 MPa or less.

[0106] A high storage modulus G’ is suitable for suppressing the shrinkage of the adhesive sheet called thermal non-uniformity during heating. However, an excessively high storage modulus G’ sometimes becomes the main cause leading to a decrease in the adhesion between the adhesive and the substrate.

[0107] [Anchoring layer]

[0108] The anchoring layer 3 containing polymer C can be formed from an anchoring layer coating liquid. The anchoring layer coating liquid contains a solvent S containing an organic solvent and polymer C.

[0109] (Solvent S containing an organic solvent)

[0110] The solvent S contains an organic solvent. The solvent S can be an organic solvent or a mixed solvent of an organic solvent and water. The organic solvent can be a polar organic solvent such as alcohol. The solvent S can contain water and alcohol. The solvent S can be a mixed solvent containing 65% by weight or more and less than 100% by weight of water and containing more than 0% by weight and 35% by weight or less of alcohol, or can be a mixed solvent containing 0% by weight or more and 35% by weight or less of water and containing 65% by weight or more and 100% by weight of alcohol. By appropriately adjusting the content ratios of water and alcohol in the mixed solvent, the dispersion stability of the solute contained in the anchoring layer coating liquid can be improved. Therefore, the generation of foreign substances in the anchoring layer can be suppressed. In particular, a mixed solvent containing 65% by weight or more and less than 100% by weight of water and containing more than 0% by weight and 35% by weight or less of alcohol (hereinafter referred to as “water-rich mixed solvent”) can sufficiently improve the dispersibility of the conductive polythiophene-based polymer suitable as an adhesive component. As a result, the conductive performance of the anchoring layer obtained by coating the anchoring layer coating liquid and drying is further improved.

[0111] On the other hand, in the case of using a mixed solvent containing 0% by weight or more and 35% by weight or less of water and containing 65% by weight or more and 100% by weight of alcohol (hereinafter referred to as “alcohol-rich mixed solvent”), the compatibility of the anchoring layer coating liquid, the wettability to the retardation film, the adhesion between the retardation film and the anchoring layer, and the coating appearance of the anchoring layer can be further improved.

[0112] Alcohols can be mixed with water in any proportion at room temperature (25 °C). The alcohol can be an alcohol having 1 to 6 carbon atoms, an alcohol having 1 to 4 carbon atoms, or an alcohol having 1 to 3 carbon atoms. Specific examples of the alcohol are methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-pentanol, isopentanol, sec-pentanol, tert-pentanol, 1-ethyl-1-propanol, 2-methyl-1-butanol, n-hexanol, and cyclohexanol. As the alcohol, ethanol and isopropanol are preferred, and isopropanol is more preferred. The alcohol can be used alone as one selected from the above compounds, or two or more thereof can be used in combination. Two or more alcohols can be mixed in any proportion. As the alcohol, for example, a mixed alcohol formed by mixing ethanol and isopropanol in any proportion can be used.

[0113] The solvent S may contain a mixed solvent of water and an alcohol as a main component. Thereby, the optical properties of the optical film can be further improved. In addition, by containing a mixed solvent of water and an alcohol as a main component, the durability of the optical laminate in a high-temperature environment and a high-humidity environment can be further improved. In this specification, the "main component" means the component having the largest content based on weight. The total amount of water and alcohol contained in the solvent S can be 90% by weight or more, 95% by weight or more, 99% by weight or more, or 100% by weight.

[0114] (Polymer C)

[0115] The anchor coating liquid contains Polymer C. Polymer C may contain at least one selected from polyoxyalkylene-containing polymers and polyurethane polymers. Hereinafter, the details of these polymers will be described.

[0116] (Polyoxyalkylene-containing polymer)

[0117] Examples of the polyoxyalkylene-containing polymer are polyoxyalkylene poly(meth)acrylates. The polyoxyalkylene poly(meth)acrylate has a structure in which the main chain is a poly(meth)acrylate polymer and polyoxyalkylene such as polyoxyethylene and polyoxypropylene are contained in the side chain. The polyoxyalkylene-containing polymer can be a poly(meth)acrylate containing polyoxyethylene.

[0118] In the anchor coating liquid, the weight part of the polyoxyalkylene-containing polymer relative to 100 weight parts of the solvent S can be 0.005 to 5, 0.01 to 3, 0.01 to 1, or 0.01 to 0.5.

[0119] (Polyurethane polymer)

[0120] Examples of the polyurethane polymer are water-soluble polyurethane resin adhesives and water-dispersible polyurethane resin adhesives. In this specification, "water-soluble" means that the solubility of the solute in 100 g of water is 5 g or more.

[0121] Polyurethane polymers, for example, can contribute to an improvement in the anchoring force of the adhesive sheet. Specifically, by including a polyurethane polymer in Polymer C, the adhesion between the retardation film 2 and the adhesive sheet 4 can be improved.

[0122] In the coating liquid for the anchoring layer, the parts by weight of the polyurethane polymer relative to 100 parts by weight of the solvent S100 may be 0.005 to 5, may be 0.01 to 3, may be 0.01 to 1, and may also be 0.01 to 0.5.

[0123] (including oxazoline group polymer)

[0124] Polymer C may include a oxazoline group polymer. The oxazoline group polymer includes a main chain composed of an acrylic backbone or a styrene backbone. In addition, the oxazoline group polymer has an oxazoline group in the side chain. The oxazoline group polymer may be an oxazoline group-containing acrylic polymer including a main chain composed of an acrylic backbone and having an

[0125] Examples of the oxazoline group are 2- oxazoline group, 3- oxazoline group, and 4- oxazoline group. The oxazoline group may be 2- oxazoline group.

[0126] The oxazoline group polymer may have a number average molecular weight of 5000 or more, or may have a number average molecular weight of 10000 or more. The upper limit value of the number average molecular weight of the oxazoline group polymer is not particularly limited, and is, for example, 1000000. By appropriately adjusting the number average molecular weight of the oxazoline group polymer, the anchoring layer can have a desired strength.

[0127] The oxazoline value of the oxazoline group polymer may be 1500 g solid / eq. or less, may be 1200 g solid / eq. or less, may be 1000 g solid / eq. or less, may be 500 g solid / eq. or less, and may also be 300 g solid / eq. or less. The oxazolinyl group reacts with functional groups such as carboxyl and hydroxyl groups contained in the adhesive composition (I) at a relatively low temperature. Therefore, by including an oxazolinyl group-containing polymer in the anchoring layer, the adhesion between the anchoring layer and the adhesive sheet can be improved.

[0128] Examples of the oxazolinyl group-containing polymer include oxazolinyl group-containing acrylic polymers and oxazolinyl group-containing acrylic / styrene polymers. Examples of the oxazolinyl group-containing acrylic polymers are Epocros WS-300, Epocros WS-500, and Epocros WS-700 manufactured by Nippon Shokubai Co., Ltd. Examples of the oxazolinyl group-containing acrylic / styrene polymers are the Epocros K-1000 series and Epocros K-2000 series manufactured by Nippon Shokubai Co., Ltd. The oxazolinyl group-containing polymer can be used alone, selected from one of the above polymers, or two or more of them can be used in combination.

[0129] (Other polymers)

[0130] Polymer C may include epoxy resin-based adhesives, isocyanate resin-based adhesives, and polyester resin-based adhesives as other polymers. In addition, Polymer C may include polymers containing amino groups in the molecule and resins (polymers) having organic reactive groups such as oxazolinyl group-containing acrylic resin-based adhesives.

[0131] (Polythiophene-based polymers)

[0132] In order to improve the conductivity of the anchoring layer and the optical properties of the optical laminate, Polymer C may further include polythiophene-based polymers.

[0133] Examples of the polythiophene-based polymers are water-soluble polythiophene-based polymers and water-dispersible polythiophene-based polymers. The weight-average molecular weight of the polythiophene-based polymers in terms of polystyrene conversion may be 400,000 or less, or may be 300,000 or less. By appropriately adjusting the weight-average molecular weight, the polythiophene-based polymers can meet water solubility or water dispersibility. By using a water-soluble polythiophene-based polymer or a water-dispersible polythiophene-based polymer to prepare the anchoring layer coating solution, the anchoring layer coating solution can have an appropriate viscosity, and thus an anchoring layer with a uniform film thickness can be formed.

[0134] The solubility of the water-soluble polythiophene-based polymer in 100 g of water may be 20 to 30 g.

[0135] A water-dispersible polythiophene polymer refers to a polythiophene polymer that is dispersed in water in the form of fine particles. Since the aqueous dispersion containing the water-dispersible polythiophene polymer can have a low viscosity, the anchoring layer coating liquid can be easily coated on the substrate. In addition, by using such an aqueous dispersion, the anchoring layer can have a uniform film thickness. The size of the fine particles is not limited to a specific value, for example, it is 1 μm or less.

[0136] The water-soluble polythiophene polymer and the water-dispersible polythiophene polymer may have hydrophilic functional groups in the molecule. Examples of the hydrophilic functional group are a sulfo group, an amino group, an amide group, an imino group, a quaternary ammonium salt group, a hydroxyl group, a mercapto group, a hydrazino group, a carboxyl group, a sulfate group, a phosphate group, and salts thereof. By having a hydrophilic functional group in the molecule, the solubility in water is increased or it is easily dispersed in water in the form of fine particles. In addition, by having a hydrophilic functional group in the molecule, the water-soluble polythiophene polymer and the water-dispersible polythiophene polymer can be easily prepared.

[0137] As a specific example of the water-soluble polythiophene polymer and the water-dispersible polythiophene polymer, Denatron P-580W manufactured by Nagase ChemteX Corporation can be cited.

[0138] In the anchoring layer coating liquid, the weight part Wc of the polymer C relative to 100 weight parts of the solvent S100 can be 0.01 or more and 0.5 or less, can also be 0.03 or more and 0.3 or less, can also be 0.05 or more and 0.2 or less, and can further be 0.08 or more and 0.15 or less. By appropriately adjusting Wc, the thickness of the anchoring layer can be appropriately adjusted, and a decrease in the adhesion between the retardation film containing the polycarbonate resin and the anchoring layer can be suppressed. It should be noted that in this specification, Wc is sometimes referred to as the base concentration.

[0139] If necessary, additives can be incorporated into the anchoring layer coating liquid. As the additives, a leveling agent, an antifoaming agent, a thickener, an antioxidant, etc. can be cited. The ratio of these additives is usually about 0.01 to 500 weight parts, can also be 0.1 to 300 weight parts, and can further be 1 to 100 weight parts relative to 100 weight parts of the polymer C.

[0140] The anchoring layer 3 can be formed, for example, by coating the anchoring layer coating liquid on the retardation film and drying it. Details of the method for producing the anchoring layer 3 will be described later. The anchoring layer 3 contains the polymer C. The polymer C may contain at least one selected from a polyoxyalkylene polymer and a polyurethane polymer.

[0141] The thickness of the anchoring layer 3 is 15 nm or more and 28 nm or less. Thus, an optical laminate 1 with improved adhesion and impact resistance can be obtained. The thickness of the anchoring layer 3 can be 16 nm or more, or can be 17 nm or more. The upper limit value of the thickness of the anchoring layer 3 can be 27 nm or less, 26 nm or less, 25 nm or less, 24 nm or less, 23.5 nm or less, 23 nm, and further can be 22.5 nm or less. It should be noted that the thickness of the anchoring layer 3 can be determined based on the average thickness. The average thickness of the anchoring layer can be measured by the method described in the column of the examples.

[0142] [Phase difference film]

[0143] The phase difference film contains a polycarbonate resin. The phase difference film is composed of, for example, a stretched film of a resin film. The phase difference film can contain a polycarbonate resin as the main component. The content rate of the polycarbonate resin in the phase difference film is, for example, 50% by weight or more, and can also be 60% by weight or more, 70% by weight or more, 80% by weight or more, and further can be 85% by weight or more. The upper limit value of the content rate can be 99.5% by weight or less, 99% by weight or less, 97% by weight or less, 95% by weight or less, 93% by weight or less, and further can be 90% by weight or less. The phase difference film can contain only a polycarbonate resin as the resin.

[0144] The polycarbonate resin has a carbonate bond that bonds structural units to each other. The polycarbonate resin can have an ester bond as a bond between structural units while having a carbonate bond. In other words, the polycarbonate resin can contain a polyester carbonate resin.

[0145] The polycarbonate resin can contain at least one structural unit selected from the structural unit represented by the following general formula (1) and the structural unit represented by the following general formula (2). These structural units are structural units derived from divalent oligofluorene, and hereinafter, are sometimes referred to as oligofluorene structural units. Such a polycarbonate resin and the like have positive refractive index anisotropy.

[0146] [Chemical formula 1]

[0147]

[0148] [Chemical formula 2]

[0149]

[0150] <Oligofluorene structural unit>

[0151] The oligofluorene structural unit is represented by the above general formula (1) or (2). In the general formulas (1) and (2), R 1 ~R 3Each independently represents a direct bond, a substituted or unsubstituted alkylene group having 1 to 4 carbon atoms, R 4 ~R 9 Each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 10 carbon atoms, a substituted or unsubstituted aryl group having 4 to 10 carbon atoms, a substituted or unsubstituted acyl group having 1 to 10 carbon atoms, a substituted or unsubstituted alkoxy group having 1 to 10 carbon atoms, a substituted or unsubstituted aryloxy group having 1 to 10 carbon atoms, a substituted or unsubstituted amino group, a substituted or unsubstituted vinyl group having 1 to 10 carbon atoms, a substituted or unsubstituted ethynyl group having 1 to 10 carbon atoms, a sulfur atom having a substituent, a silicon atom having a substituent, a halogen atom, a nitro group or a cyano group. Among them, R 4 ~R 9 May be the same or different from each other optionally, and at least two adjacent groups among R 4 ~R 9 Can also bond to each other to form a ring.

[0152] The content of the oligofluorene structural unit in the polycarbonate resin can be 1% by weight to 40% by weight, can also be 10% by weight to 35% by weight, can also be 15% by weight to 30% by weight, and can also be 18% by weight to 25% by weight relative to the whole resin. By appropriately adjusting the content of the oligofluorene structural unit, the absolute value of the photoelastic coefficient can be adjusted to a desired range, the reliability can be improved, and the retardation performance can be improved. By appropriately adjusting the content of the oligofluorene structural unit, a retardation film having desired properties can be manufactured.

[0153] <Other Structural Units>

[0154] The polycarbonate resin may contain other structural units in addition to the oligofluorene structural unit. Examples of other structural units can be structural units derived from dihydroxy compounds or diester compounds. For example, in order to exhibit the target inverse dispersion wavelength property, it is necessary to introduce a structural unit having positive birefringence together with an oligofluorene structural unit having negative birefringence into the polymer structure. Therefore, as other structural units (monomers) to be copolymerized, they can be dihydroxy compounds or diester compounds that are raw materials for structural units having positive birefringence.

[0155] As copolymer monomers, there can be mentioned: compounds capable of introducing a structural unit containing an aromatic ring; and compounds that do not introduce a structural unit containing an aromatic ring, that is, compounds composed of an aliphatic structure.

[0156] Examples of compounds composed of aliphatic structures are dihydroxy compounds of straight-chain aliphatic hydrocarbons, dihydroxy compounds of branched aliphatic hydrocarbons, secondary alcohols of alicyclic hydrocarbons, tertiary alcohols of alicyclic hydrocarbons, primary alcohols of alicyclic hydrocarbons, oxyalkylene diols, dihydroxy compounds having a cyclic ether structure, dihydroxy compounds having a cyclic acetal structure, alicyclic dicarboxylic acids, and aliphatic dicarboxylic acids. Specific examples of dihydroxy compounds of straight-chain aliphatic hydrocarbons are ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-heptanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol. Specific examples of dihydroxy compounds of branched aliphatic hydrocarbons are neopentyl glycol and hexanediol. Specific examples of secondary alcohols of alicyclic hydrocarbons are 1,2-cyclohexanediol, 1,4-cyclohexanediol, and hydrogenated bisphenol A. Specific examples of tertiary alcohols of alicyclic hydrocarbons are 1,3-adamantanediol and 2,2,4,4-tetramethyl-1,3-cyclobutanediol. Specific examples of primary alcohols of alicyclic hydrocarbons are 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, pentacyclopentadecane dimethanol, 2,6-naphthalane dimethanol, 1,5-naphthalane dimethanol, 2,3-naphthalane dimethanol, 2,3-norbornane dimethanol, 2,5-norbornane dimethanol, and 1,3-adamantane dimethanol. Other specific examples of primary alcohols of alicyclic hydrocarbons are dihydroxy compounds derived from terpene compounds such as limonene. Specific examples of oxyalkylene diols are diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol, and polypropylene glycol. Specific examples of dihydroxy compounds having a cyclic ether structure are isosorbide. Specific examples of dihydroxy compounds having a cyclic acetal structure are spirodiol and di alkanediol. Specific examples of alicyclic dicarboxylic acids are 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, and 1,4-cyclohexanedicarboxylic acid. Specific examples of aliphatic dicarboxylic acids are malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, and sebacic acid.

[0157] Examples of compounds capable of introducing a structural unit containing an aromatic ring are aromatic bisphenol compounds, dihydroxy compounds having an ether group bonded to an aromatic group, and aromatic dicarboxylic acids. Specific examples of aromatic bisphenol compounds are 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(3-methyl-4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-diethylphenyl)propane, 2,2-bis(4-hydroxy-(3-phenyl)phenyl)propane, 2,2-bis(4-hydroxy-(3,5-diphenyl)phenyl)propane, 2,2-bis(4-hydroxy-3,5-dibromophenyl)propane, bis(4-hydroxyphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxyphenyl)butane, 2,2-bis(4-hydroxyphenyl)pentane, 1,1-bis(4-hydroxyphenyl)-1-phenylethane, bis(4-hydroxyphenyl)diphenylmethane, 1,1-bis(4-hydroxyphenyl)-2-ethylhexane, 1,1-bis(4-hydroxyphenyl)decane, bis(4-hydroxy-3-nitrophenyl)methane, 3,3-bis(4-hydroxyphenyl)pentane, 1,3-bis(2-(4-hydroxyphenyl)-2-propyl)benzene, 1,3-bis(2-(4-hydroxyphenyl)-2-propyl)benzene, 2,2-bis(4-hydroxyphenyl)hexafluoropropane, 1,1-bis(4-hydroxyphenyl)cyclohexane, bis(4-hydroxyphenyl)sulfone, 2,4'-dihydroxydiphenyl sulfone, bis(4-hydroxyphenyl)sulfide, bis(4-hydroxy-3-methylphenyl)sulfide, bis(4-hydroxyphenyl)disulfide, 4,4'-dihydroxydiphenyl ether, and 4,4'-dihydroxy-3,3'-dichlorodiphenyl ether. Specific examples of dihydroxy compounds having an ether group bonded to an aromatic group are 2,2-bis(4-(2-hydroxyethoxy)phenyl)propane, 2,2-bis(4-(2-hydroxypropoxy)phenyl)propane, 1,3-bis(2-hydroxyethoxy)benzene, 4,4'-bis(2-hydroxyethoxy)biphenyl, and bis(4-(2-hydroxyethoxy)phenyl)sulfone. Specific examples of aromatic dicarboxylic acids are terephthalic acid, phthalic acid, isophthalic acid, 4,4'-diphenyldicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-benzophenonedicarboxylic acid, 4,4'-diphenoxyethanedicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid, and 2,6-naphthalenedicarboxylic acid.

[0158] It should be noted that the aliphatic dicarboxylic acids and aromatic dicarboxylic acids described above can be used as raw materials for the polyester carbonate resin in the form of the dicarboxylic acids themselves. However, depending on the manufacturing method, dicarboxylic acid esters such as methyl ester bodies and phenyl ester bodies, and dicarboxylic acid derivatives such as dicarboxylic acid halides can also be used as raw materials.

[0159] As a comonomer, a compound known as a compound having a structural unit with negative birefringence can be used in combination with an oligofluorene compound. Examples of such compounds are dihydroxy compounds having a fluorene ring and dicarboxylic acid compounds having a fluorene ring. Examples of the dihydroxy compound having a fluorene ring are 9,9-bis(4-(2-hydroxyethoxy)phenyl)fluorene, 9,9-bis(4-hydroxyphenyl)fluorene, and 9,9-bis(4-hydroxy-3-methylphenyl)fluorene.

[0160] Among the structural units that can be introduced into a polycarbonate resin through a compound having an alicyclic structure, a structural unit represented by the following formula (3) can be contained as a copolymer component.

[0161] [Chemical formula 3]

[0162]

[0163] As the dihydroxy compound capable of introducing the structural unit represented by formula (3), spirodiol can be mentioned.

[0164] In the polycarbonate resin, the content of the structural unit represented by formula (3) can be 5% by weight or more and 90% by weight or less. The upper limit of the content can be 70% by weight or 50% by weight. The lower limit of the content can be 10% by weight, 20% by weight, or 25% by weight. By making the content of the structural unit represented by formula (3) 5% by weight or more, the mechanical properties and heat resistance can be improved, and a low photoelastic coefficient can be obtained. In addition, the compatibility with an acrylic resin is improved, and the transparency of the resulting resin composition can be further improved. Further, by making the content 90% by weight or less, the rate of the polymerization reaction of spirodiol is relatively slow, and thus, the polymerization reaction is easily controlled.

[0165] The polycarbonate resin can further contain a structural unit represented by the following formula (4) as a copolymer component.

[0166] [Chemical formula 4]

[0167]

[0168] As the dihydroxy compound capable of introducing the structural unit represented by formula (4), isosorbide (ISB), isomannitol, and isoidet in a stereoisomeric relationship can be mentioned. These dihydroxy compounds can be used alone or in combination of two or more.

[0169] In the polycarbonate resin, the content rate of the structural unit represented by the formula (4) can be 5% by weight or more and 90% by weight or less. The upper limit of the content rate can be 70% by weight or less, or can be 50% by weight or less. The lower limit of the content rate can be 10% by weight or more, or can be 15% by weight or more. By appropriately adjusting the content rate of the structural unit represented by the formula (4), the mechanical properties and heat resistance can be improved, and a low photoelastic coefficient can be obtained. In addition, by appropriately adjusting the content rate of the structural unit represented by the formula (4), the dimensional change of the molded body caused by the water absorption of the resin can be suppressed to an allowable range.

[0170] The polycarbonate resin may further contain other structural units. It should be noted that such structural units are referred to as "other structural units". As monomers having other structural units, examples include: 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, and 1,4-cyclohexanedicarboxylic acid, and their derivatives. The other structural units can be 1,4-cyclohexanedimethanol and tricyclodecane dimethanol. The balance of optical properties, heat resistance, mechanical properties, etc. of the resin containing the structural units derived from these monomers is excellent. It should be noted that the polymerization reactivity of the diester compound is relatively low. Therefore, from the viewpoint of improving the reaction efficiency, a diester compound other than the diester compound containing the oligofluorene structural unit may not be used.

[0171] The glass transition temperature (Tg) of the polycarbonate resin is, for example, 110 °C or more and 160 °C or less. The glass transition temperature can be 155 °C or less, or can be 150 °C or less, and further can be 145 °C or less. The glass transition temperature can be 120 °C or more, or can be 130 °C or more. By making the glass transition temperature within the above range, the heat resistance of the polycarbonate resin can be improved. As a result, the dimensional change during film formation can be suppressed, and the reliability of the quality of the optical laminate under use conditions can be improved. In addition, by making the glass transition temperature within the above range, the stretchability and transparency can be improved.

[0172] Details of the oligofluorene structural unit, and details of the composition and manufacturing method of the polycarbonate resin, etc. are described, for example, in International Publication No. 2015 / 159928 pamphlet.

[0173] <Acrylic resin>

[0174] The retardation film may further contain an acrylic resin. The content of the acrylic resin is, for example, 0.5% by weight to 1.5% by weight.

[0175] As the acrylic resin, an acrylic resin as a thermoplastic resin can be used. As monomers that are structural units of the acrylic resin, for example, the following compounds can be cited: methyl methacrylate, methacrylic acid, methyl acrylate, acrylic acid, benzyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, glycidyl (meth)acrylate, hydroxypropyl (meth)acrylate, 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, cyclohexyl (meth)acrylate, isobornyl (meth)acrylate, norbornyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentyl (meth)acrylate, dicyclopentenoxyethyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, acryloyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, 2-(meth)acryloyloxyethyl succinate, 2-(meth)acryloyloxyethyl maleate, 2-(meth)acryloyloxyethyl phthalate, 2-(meth)acryloyloxyethyl hexahydrophthalate, (meth)acryloyloxypentamethylpiperidine, (meth)acryloyloxytetramethylpiperidine, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, cyclopentyl methacrylate, cyclopentyl acrylate, cyclohexyl methacrylate, cyclohexyl acrylate, cycloheptyl methacrylate, cycloheptyl acrylate, cyclooctyl methacrylate, cyclooctyl acrylate, cyclododecyl methacrylate, cyclododecyl acrylate. These compounds can be used alone or in combination of two or more. Examples of the mode of using two or more monomers in combination include copolymerization of two or more monomers, blends of two or more in the homopolymer of one monomer, and combinations thereof. In addition, other monomers capable of copolymerizing with these acrylic monomers (for example, olefin monomers, vinyl monomers) can also be used in combination.

[0176] The acrylic resin contains structural units derived from methyl methacrylate. The content rate of the structural units derived from methyl methacrylate in the acrylic resin can be 70% by mass or more and 100% by mass or less. The content rate can be 80% by mass or more, can also be 90% by mass or more, and further can be 95% by mass or more. If it is within this range, excellent compatibility with the polycarbonate resin of the present invention can be obtained. As the structural units other than methyl methacrylate, methyl acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, and styrene are preferably used. By copolymerizing methyl acrylate, the thermal stability can be improved. By using phenyl (meth)acrylate, benzyl (meth)acrylate, and styrene, the refractive index of the acrylic resin can be adjusted. Therefore, by matching the refractive index of the combined resin, the transparency of the obtained resin composition can be improved. By using such an acrylic resin, a reverse dispersion retardation film having excellent elongation and retardation performance and a small haze can be obtained.

[0177] The weight-average molecular weight Mw of the acrylic resin is, for example, 10,000 or more and 200,000 or less. The weight-average molecular weight can be 30,000 or more, and can also be 50,000 or more. In addition, the weight-average molecular weight can be 180,000 or less, and can also be 150,000 or less. If the weight-average molecular weight is within such a range, compatibility with the polycarbonate resin can be obtained. As a result, the transparency of the final retardation film can be improved, and the elongation during stretching can be sufficiently improved. The weight-average molecular weight of the acrylic resin is the molecular weight in terms of polystyrene measured by GPC. In addition, from the viewpoint of compatibility, the acrylic resin preferably substantially does not contain a branched structure. The absence of a branched structure can be confirmed by the GPC curve of the acrylic resin being unimodal.

[0178] As described above, the retardation film is composed of, for example, a stretched film of a resin film. The retardation film, for example, satisfies Re(450) < Re(550). The retardation film can further satisfy Re(550) < Re(650). The retardation film can exhibit an inverse dispersion wavelength dependence in which the retardation value increases corresponding to the wavelength of the measurement light. Re(450) / Re(550) of the retardation film is, for example, more than 0.5 and less than 1.0, preferably 0.7 or more and 0.95 or less, more preferably 0.75 or more and 0.92 or less, and further preferably 0.8 or more and 0.9 or less. Re(650) / Re(550) is preferably 1.0 or more and less than 1.15, more preferably 1.03 or more and 1.1 or less.

[0179] Re(450) refers to the in-plane retardation of the film measured at 23°C with light of a wavelength of 450 nm. Re(550) refers to the in-plane retardation of the film measured at 23°C with light of a wavelength of 550 nm. When the thickness of the film is set to d (nm), Re(λ) can be obtained by Re = (nx - ny) × d. "nx" refers to the refractive index in the direction where the in-plane refractive index is maximum (i.e., the slow axis direction). "ny" refers to the refractive index in the direction orthogonal to the slow axis in the plane (i.e., the fast axis direction).

[0180] The in-plane retardation Re(550) of the retardation film can be 100 nm or more and 200 nm or less, can be 110 nm or more and 180 nm or less, can be 120 nm or more and 160 nm or less, or can be 130 nm or more and 150 nm or less. The retardation film can function as a so-called λ / 4 wave plate.

[0181] The retardation film, for example, has an in-plane retardation. Therefore, the retardation film can have a relationship of nx > ny. As long as the retardation film has a relationship of nx > ny, it exhibits any appropriate refractive index characteristics. The refractive index characteristics of the retardation film typically exhibit a relationship of nx > ny ≥ nz. "nz" refers to the refractive index in the thickness direction. It should be noted that here, "ny = nz" includes not only the case where ny and nz are exactly equal but also the case where they are substantially equal. Therefore, within the range that does not impair the effects of the present invention, there may be a case where ny < nz.

[0182] The Nz coefficient of the retardation film can be 0.9 or more and 2.0 or less, can be 0.9 or more and 1.5 or less, or can be 0.9 or more and 1.2 or less. By satisfying such a relationship, when the optical laminate including the retardation film is used in an image display device, a very excellent reflected hue can be achieved. Here, the "Nz coefficient" is a coefficient obtained by Nz = Rth / Re. "Rth(λ)" is the retardation in the thickness direction of the film measured at 23°C with light of a wavelength of λ nm. For example, "Rth(450)" is the retardation in the thickness direction of the film measured at 23°C with light of a wavelength of 450 nm. "Rth(550)" is the retardation in the thickness direction of the film measured at 23°C with light of a wavelength of 550 nm. When the thickness of the film is set to d (nm), Rth(λ) can be obtained by Rth = (nx - nz) × d.

[0183] The thickness of the retardation film can be set in such a way that it can function most suitably as a λ / 4 wave plate. In other words, the thickness can be set in such a way that a desired in-plane retardation can be obtained. Specifically, the thickness can be 15 μm or more and 80 μm or less, can be 20 μm or more and 70 μm or less, and can also be 30 μm or more and 60 μm or less.

[0184] The absolute value of the photoelastic coefficient of the retardation film can be 20×10 -12 (m 2 / N) or less, can be 1.0×10 -12 (m 2 / N) to 15×10 -12 (m 2 / N), and can also be 2.0×10 -12 (m 2 / N) to 12×10 -12 (m 2 / N). If the absolute value of the photoelastic coefficient is in such a range, display unevenness can be suppressed when the optical laminate including the retardation film is applied to an image display device.

[0185] The main surface of the anchoring layer 3 on which the retardation film 2 is formed can be subjected to a surface modification treatment. By performing the surface modification treatment, the adhesion between the retardation film 2 and the anchoring layer 3 can be further improved. Examples of the surface modification treatment include corona treatment, plasma treatment, excimer treatment, and flame treatment. The main surface of the anchoring layer 3 on which the retardation film 2 is formed can be subjected to corona treatment and / or plasma treatment as the surface modification treatment, or can be subjected to plasma treatment.

[0186] The conditions of the plasma treatment are represented by the discharge amount, for example, 0.5 to 100 kJ / m 2 . The discharge amount can be 1 kJ / m 2 or more, 2 kJ / m 2 or more, and further can be 5 kJ / m 2 or more. The upper limit value of the discharge amount can be 50 kJ / m 2 , 40 kJ / m 2 , 30 kJ / m 2 , 20 kJ / m 2 , and further can be 10 kJ / m 2 . By appropriately adjusting the discharge amount in the plasma treatment, the adhesion between the retardation film 2 and the anchoring layer 3 can be further improved.

[0187] The optical laminate can further include a polarizing film and a surface protective film. An example of such an optical film is shown in Figure 2 . Figure 2It is a schematic cross-sectional view showing another example of an optical laminate. Figure 2 The optical laminate 1B has a laminated structure in which an adhesive sheet 4, an anchoring layer 3, a retardation film 2A, an interlayer adhesive sheet 5, a polarizing film 6, and a surface protective film 7 are laminated in this order.

[0188] As the interlayer adhesive sheet 5, a known adhesive can be used. The adhesive sheet 4 can be used as the interlayer adhesive sheet 5.

[0189] The polarizing film 6 includes a polarizer. The polarizing film 6 typically includes a polarizer and a protective film (transparent protective film). The protective film is disposed, for example, in contact with the main surface of the polarizer. The polarizer can be disposed between two protective films. The protective film can be disposed on at least one surface of the polarizer.

[0190] The polarizer is not particularly limited. For example, a film obtained by adsorbing a dichroic substance such as iodine or a dichroic dye onto a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, or a partially saponified ethylene-vinyl acetate copolymer film and performing unidirectional stretching; a polyene-oriented film such as a dehydrated product of polyvinyl alcohol or a hydrochloric acid-removed product of polyvinyl chloride, etc. The polarizer is typically formed of a polyvinyl alcohol film (the polyvinyl alcohol film includes a partially saponified ethylene-vinyl acetate copolymer film) and a dichroic substance such as iodine.

[0191] The thickness of the polarizer is not particularly limited. For example, it is 80 μm or less, and can be 50 μm or less, 30 μm or less, 25 μm or less, and further can be 20 μm or less. The lower limit of the thickness of the polarizer is not particularly limited. For example, it is 1 μm or more, and can be 5 μm or more, 10 μm or more, and further can be 15 μm or more. The dimensional change of a thin polarizer (for example, with a thickness of 20 μm or less) can be suppressed, which can contribute to the improvement of the durability of the optical laminate, especially the durability at high temperatures.

[0192] As the material for the protective film, a thermoplastic resin having excellent properties such as transparency, mechanical strength, thermal stability, moisture barrier property, and isotropy can be used. Specific examples of such thermoplastic resins include cellulose resins such as cellulose triacetate, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, cyclic olefin resins (norbornene resins), polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The material for the protective film may be a thermosetting resin or an ultraviolet curable resin such as (meth)acrylic, urethane, acrylic urethane, epoxy, or silicone. When the polarizing film has two protective films, the materials of the two protective films may be the same or different. For example, a protective film made of a thermoplastic resin can be adhered to one main surface of the polarizer through an adhesive, and a protective film made of a thermosetting resin or an ultraviolet curable resin can be adhered to the other main surface of the polarizer. The protective film may contain one or more arbitrary additives. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, anti-coloring agents, flame retardants, nucleating agents, antistatic agents, pigments, coloring agents, etc.

[0193] The thickness of the protective film can be appropriately determined. Generally, considering operability such as strength and processability, and film properties, it is about 10 to 200 μm.

[0194] The polarizer and the protective film are usually bonded together via an aqueous adhesive or the like. Examples of aqueous adhesives include isocyanate adhesives, polyvinyl alcohol adhesives, gelatin adhesives, vinyl-based latexes, aqueous polyurethanes, aqueous polyesters, etc. Examples of other adhesives other than the above adhesives include ultraviolet curable adhesives, electron beam curable adhesives, etc. The electron beam curable adhesive for polarizing films shows appropriate adhesiveness to various protective films. The adhesive may also contain a metal compound filler.

[0195] In the polarizing film 6, a retardation film or the like can be formed on the polarizer instead of the protective film, and another protective film, a retardation film, etc. can be further provided on the protective film.

[0196] For the protective film, a hard coat can be provided on the surface of the protective film opposite to the surface adhered to the polarizer, or it can be subjected to treatments for the purposes of antireflection, anti-adhesion, diffusion prevention, antiglare, etc.

[0197] The polarizing film 6 can be a circularly polarizing film.

[0198] The surface protective film 7 has the function of protecting the outermost polarizing film 6 during the circulation and storage of the optical laminate 1B, and also in the state where the optical laminate 1B is introduced into an image display device. Additionally, in the state where it is introduced into an image display device, the surface protective film 7 can be a protective film that functions as a window to the external space. The surface protective film 7 is typically a resin film. The resin constituting the surface protective film 7 is, for example, polyester such as PET, polyolefins such as polyethylene and polypropylene, acrylic acid, cycloolefin, polyimide, and polyamide, and polyester is preferred. However, it should be noted that the surface protective film 7 is not limited to the above examples, and the surface protective film 7 can also be a glass film or a laminated film containing a glass film. Surface treatments such as antiglare, antireflection, and antistatic can be applied to the surface protective film 7.

[0199] The surface protective film 7 can be joined to the polarizing film 6 with any adhesive. Joining can also be achieved using the adhesive sheet 4.

[0200] The optical laminate of the present embodiment can typically be used in an image display device. The image display device is, for example, an EL display such as a liquid crystal display, an organic EL display, and an inorganic EL display.

[0201] (Method for manufacturing an optical laminate)

[0202] The method for manufacturing the optical laminate of the present embodiment includes: coating an anchoring layer coating liquid containing a solvent S containing an organic solvent and a polymer C on a retardation film to form a coating film with a thickness of T (μm); and drying the coating film. Here, the optical laminate includes a retardation film, an anchoring layer, and an adhesive sheet. The optical laminate is an optical laminate in which a retardation film, an anchoring layer, and an adhesive sheet are laminated in sequence. The retardation film contains a polycarbonate resin. The anchoring layer contains the polymer C. In the anchoring layer coating liquid, the weight part Wc of the polymer C with respect to 100 weight parts of the solvent S is 0.01 or more and 0.5 or less. In addition, the converted thickness of the coating film obtained by the following formula (1) is 2 μm or more and 10 μm or less. This converted thickness is a value converted to the thickness when using a coating liquid with Wc of 0.1 weight part.

[0203] Converted thickness of coating film = T × Wc / 0.1 (1)

[0204] The method for manufacturing the optical laminate includes: forming an anchoring layer 3 on the retardation film 2 and forming an adhesive sheet 4 on the anchoring layer 3.

[0205] Forming the anchoring layer 3 on the retardation film 2 includes: coating the anchoring layer coating liquid on the retardation film 2 to form a coating film with a thickness of T (μm), and drying the obtained coating film.

[0206] As a method for coating the anchoring layer coating liquid on the retardation film 2, for example, there can be cited: roll coating method, roll kiss coating method, gravure coating method, reverse coating method, roll brush coating method, spraying method, dip roll coating method, bar coating method, knife coating method, air knife coating method, curtain coating method, die lip coating method, extrusion coating method using a die coater, etc. The coating amount of the anchoring layer coating liquid can be appropriately adjusted according to the thickness of the target anchoring layer 3.

[0207] The thickness of the coating film obtained by coating the anchoring layer coating liquid on the retardation film 2, that is, T (μm), can be 1 μm or more and 20 μm or less, can also be 2 μm or more and 10 μm or less, and can further be 2.5 μm or more and 8 μm or less. By appropriately adjusting T (μm), the coating appearance of the obtained anchoring layer 3 is improved. The measurement method of T (μm) is described in the column of the examples.

[0208] The converted thickness of the coating film represented by the above formula (1) is 2 μm or more and 10 μm or less, and can be 4 μm or more and 8 μm or less.

[0209] By drying the coating film, the coating film is cured, thereby forming the anchoring layer 3. The drying temperature of the coating film is, for example, 100 °C or lower, can also be 90 °C or lower, 80 °C or lower, 70 °C or lower, and further can be 60 °C or lower. The drying temperature of the coating film can be room temperature (25 °C), can also be 30 °C or higher, can also be 40 °C or higher, and can further be 45 °C or higher.

[0210] The drying time of the coating film can be appropriately adjusted according to the composition of the anchoring layer 3, can be 5 to 100 seconds, can also be 5 to 70 seconds, and can further be 10 to 35 seconds. By appropriately adjusting the drying time of the coating film, the coating appearance of the anchoring layer 3 can be improved.

[0211] By forming the adhesive sheet 4 on the anchoring layer 3 after forming the anchoring layer 3 on the retardation film 2, the optical laminate 1 can be manufactured. For example, by transferring the adhesive sheet 4 formed on the release sheet to the anchoring layer 3, the adhesive sheet 4 can be formed on the anchoring layer 3.

[0212] In the method of transferring the adhesive sheet 4 formed on the release sheet to the anchoring layer 3, first, the adhesive sheet 4 is formed on the release sheet. The method of forming the adhesive sheet 4 on the release sheet is as described in the above [Method for manufacturing adhesive sheet] column.

[0213] Next, by transferring the adhesive sheet 4 to the anchoring layer 3, the optical laminate 1 can be obtained.

[0214] [Image display device]

[0215] The image display device, for example, includes an optical laminate and an image forming layer. Figure 3It is a cross-sectional view schematically showing an example of the image display device of the present embodiment. Figure 3 The image display device 11 includes a substrate 9, an image forming layer (such as an organic EL layer or a liquid crystal layer) 8, and an optical laminate 1A. Specifically, the image display device 11 has a laminated structure in which a substrate 9, an image forming layer 8, an adhesive sheet 4, an anchor layer 3, and a retardation film 2 are laminated in sequence. The image display device 11 may also have Figure 2 an optical laminate 1B in place of the optical laminate 1A. The substrate 9 and the image forming layer 8 may have the same configurations as the substrate and the image forming layer included in a known image display device, respectively.

[0216] Figure 3 The image display device 11 may be an organic EL display or a liquid crystal display. However, the image display device 11 is not limited to this example, and the image display device 11 may be an electroluminescent (EL) display, a plasma display (PD), a field emission display (FED: Field Emission Display), etc. The image display device 11 can also be used for home appliance applications, in-vehicle applications, public information display (PID) applications, etc.

[0217] Examples

[0218] Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to the examples shown below.

[0219] [Storage modulus G’ (25 °C)]

[0220] The storage modulus G’ of the adhesive sheet at 25 °C was evaluated by the following method. First, a sample for measurement was prepared. As the sample for measurement, a sample obtained by punching a laminate in which a plurality of adhesive sheets were laminated into a disc shape was used. The diameter of the bottom surface of the sample for measurement was 8 mm, and the thickness of the sample for measurement was 1 mm. Next, dynamic viscoelasticity measurement was performed on the sample for measurement. The dynamic viscoelasticity measurement was performed using ARES-G2 manufactured by TA Instruments. The storage modulus G’ of the adhesive sheet at 25 °C was obtained from the results of the dynamic viscoelasticity measurement. It should be noted that the conditions for the dynamic viscoelasticity measurement are as follows.

[0221] · Measurement conditions

[0222] Frequency: 1 Hz

[0223] Deformation mode: Torsion

[0224] Measurement temperature: -70 °C to 150 °C

[0225] Heating rate: 5 °C / min

[0226] [Measurement of the Thickness T (μm) of the Coated Film]

[0227] The thickness T (μm) of the coated film obtained by coating the anchoring layer coating liquid on the retardation film was measured by the following method. Under the conditions of 23°C and 55% RH, after coating the anchoring layer coating liquid on the retardation film using a gravure coater, the thickness T (μm) of the coated film was immediately measured using a reflection spectroscopic interferometry film thickness meter (manufactured by Ocean Insight). In addition, the converted thickness of the coated film when the weight part Wc of the polymer C relative to 100 weight parts of the solvent S100 was set to 0.1 was calculated by the following formula (1).

[0228] Converted thickness of the coated film = T × Wc / 0.1 (1)

[0229] [Conventional Adhesion]

[0230] The optical laminate with a substrate of each example and comparative example was cut into a size of 25 cm × 25 cm. Next, the substrate was peeled off from the optical laminate with a substrate to expose the adhesive sheet, thereby producing an optical laminate. Then, via the adhesive sheet of the optical laminate, the optical laminate was adhered to the ITO film by reciprocating a 2 kg roller once. Then, within 1 minute, using a tensile testing machine (manufactured by Minebea, product name: TG-1KN), the optical laminate was peeled off from the ITO film under the conditions of a peeling angle of 180 degrees and a peeling speed of 300 mm / min, and the peeling force was measured. The conventional adhesion was evaluated according to the following criteria. It should be noted that the ITO film used was a polyethylene terephthalate film "125Tetolight OES" (manufactured by Oike Industry Co., Ltd.) obtained by vapor deposition treatment of SiO2. The adhesive sheet was adhered to the side on which SiO2 was vapor-deposited.

[0231] A: The peeling force is 20 N or more

[0232] B: The peeling force is 15 N or more and less than 20 N

[0233] C: The peeling force is greater than 10 N and less than 15 N

[0234] D: The peeling force is 10 N or less

[0235] [Enhanced Adhesion]

[0236] The optical laminate with a substrate in each example and comparative example was stored in an environment of 40 °C and 92% RH for 3 days or more. After storage, the optical laminate with a substrate was taken out and left to stand at room temperature for 1 hour. Then, the optical laminate with a substrate was cut into a size of 25 cm × 25 cm. Next, the substrate was peeled off from the optical laminate with a substrate to expose the adhesive sheet, thereby producing an optical laminate. Then, the optical laminate was adhered to the ITO film via the adhesive sheet of the optical laminate and reciprocated once with a 2 kg roller. Then, within 1 minute, the optical laminate was peeled off from the ITO film under the conditions of a peeling angle of 180 degrees and a peeling speed of 300 mm / min using the above-mentioned tensile testing machine, and the peeling force was measured. The promotion of adhesion was evaluated according to the following criteria. It should be noted that the ITO film used was the polyethylene terephthalate film "125Tetolight OES" obtained by vapor-depositing SiO2. The adhesive sheet was adhered to the side vapor-deposited with SiO2.

[0237] A: The peeling force is 20 N or more

[0238] B: The peeling force is 15 N or more and less than 20 N

[0239] C: The peeling force is greater than 10 N and less than 15 N

[0240] D: The peeling force is 10 N or less

[0241] [Impact resistance]

[0242] An optical laminate with a substrate for impact resistance evaluation was produced by laminating an interlayer adhesive sheet, a polarizing plate, and a surface protective film in this order on the retardation film of the optical laminate with a substrate in each example and comparative example.

[0243] (Production of interlayer adhesive sheet)

[0244] <Preparation of acrylic polymer A1>

[0245] In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen inlet tube, and a condenser, a monomer mixture containing 82.1 parts of butyl acrylate, 13 parts of benzyl acrylate, 0.1 part of 4-hydroxybutyl acrylate, and 4.8 parts of acrylic acid was added. Further, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was added together with 100 parts of ethyl acetate with respect to 100 parts of the monomer mixture, and nitrogen substitution was carried out while slowly stirring and introducing nitrogen. Then, the liquid temperature in the flask was maintained at around 55 °C, and a polymerization reaction was carried out for 8 hours to prepare a solution of acrylic polymer A1 having a weight-average molecular weight (Mw) of 2.2 million and Mw / Mn = 3.0.

[0246] With respect to 100 parts by solid content of the acrylic polymer A1 solution, 0.45 part of trimethylolpropane / toluene diisocyanate adduct (manufactured by Tosoh Corporation, trade name “Coronate L”), 0.1 part of peroxide crosslinking agent (benzoyl peroxide), 0.2 part of epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM-403”), and 0.25 part of polyether compound having a reactive silyl group (manufactured by Kaneka Corporation, trade name “Silyl SAT10”) were blended to obtain an interlayer adhesive composition.

[0247] The interlayer adhesive composition was uniformly coated on the surface of a polyethylene terephthalate film (release film) treated with a silicone-based release agent using a jet coater to obtain a coated film. Then, the coated film was dried for 2 minutes in an air-circulation type constant temperature oven at 155 °C to form an interlayer adhesive sheet with a thickness of 20 μm on the surface of the release film.

[0248] (Production of Polarizer P1)

[0249] In the production of the polarizer, first, a polarizer was produced as follows. A long strip-shaped polyvinyl alcohol (PVA) resin film (manufactured by Kuraray Co., Ltd., product name “PE3000”, thickness 30 μm) was unidirectionally stretched along the length direction (total stretching ratio 5.9 times) using a roller stretching machine, and at the same time, the above resin film was successively subjected to swelling, dyeing, crosslinking, cleaning, and drying treatments to produce a polarizer with a thickness of 12 μm. In the swelling treatment, the above resin film was stretched 2.2 times while being treated in pure water at 20 °C. In the dyeing treatment, the above resin film was stretched 1.4 times while being treated in an aqueous solution at 30 °C containing iodine and potassium iodide in a weight ratio of 1:7. The iodine concentration in the aqueous solution was adjusted so that the monomer transmittance of the produced polarizer reached 45.0%. The crosslinking treatment was carried out in two stages. In the first-stage crosslinking treatment, the above resin film was stretched 1.2 times while being treated in an aqueous solution at 40 °C in which boric acid and potassium iodide were dissolved. The content rate of boric acid in the aqueous solution used in the first-stage crosslinking treatment was set to 5.0% by weight, and the content rate of potassium iodide was set to 3.0% by weight. In the second-stage crosslinking treatment, the above resin film was stretched 1.6 times while being treated in an aqueous solution at 65 °C in which boric acid and potassium iodide were dissolved. The content rate of boric acid in the aqueous solution used in the second-stage crosslinking treatment was set to 4.3% by weight, and the content rate of potassium iodide was set to 5.0% by weight. A potassium iodide aqueous solution at 20 °C was used in the cleaning treatment. The content rate of potassium iodide in the aqueous solution used in the cleaning treatment was set to 2.6% by weight. The drying treatment was carried out under drying conditions of 70 °C and 5 minutes.

[0250] Using a polyvinyl alcohol-based adhesive, a triacetyl cellulose (TAC) film (manufactured by Konica Minolta, Inc., product name "KC2UA", thickness 25 μm) was adhered to each main surface of the polarizer produced above. Among them, a hard coat (thickness 7 μm) was formed on the main surface of the TAC film adhered to one main surface, on the side opposite to the polarizer side. In this way, a polarizing plate P1 having a structure of a protective layer / hard coat-containing protective layer / polarizer was obtained.

[0251] (Production of a substrate-containing optical laminate for impact resistance evaluation)

[0252] The interlayer adhesive sheet formed on the surface of the release film was transferred to the surface of the substrate-containing optical laminate of each example and comparative example on which the retardation film was formed, and an optical laminate with an interlayer adhesive sheet was produced. The release film of the optical laminate with an interlayer adhesive sheet was peeled off, and the polarizing plate P1 and the surface protective film were laminated in sequence. Thus, a substrate-containing optical laminate for impact resistance evaluation was produced. The substrate-containing optical laminate for impact resistance evaluation has a structure in which a substrate, an adhesive sheet, an anchor layer, a retardation film, an interlayer adhesive sheet, the polarizing plate P1, and a surface protective film are laminated in sequence. As the surface protective film, a surface protective film for electronic / engineering components (PET material, product name: E-MASKRP109F) manufactured by Nitto Denko Corporation was used.

[0253] (Edge treatment)

[0254] Edge treatment was performed on the substrate-containing optical laminate for impact resistance evaluation. First, 100 substrate-containing optical laminates for impact resistance evaluation were laminated to produce a laminate. In the lamination direction of the laminate, the laminate was held under pressure from above and below using a vise-like fixture. Next, in a direction orthogonal to the lamination direction of the laminate, a rotary cutter was used to cut the inside 1.0 mm from the edge of the laminate, thereby performing edge treatment. Thus, a sample for impact resistance evaluation was produced.

[0255] [Evaluation method for impact resistance]

[0256] The adhesive tape (Sekisui Cellotape, No. 252) was wound around a metal rod with a diameter of about 4 mm via a double-sided tape. The metal rod was pressed into the end of the sample for impact resistance evaluation. Specifically, first, the metal rod was arranged such that the long axis of the metal rod was in the same direction as the lamination direction of the sample for impact resistance evaluation and in contact with the end edge of the sample for impact resistance evaluation. Next, in a direction orthogonal to the lamination direction of the sample for impact resistance evaluation, the metal rod was pressed into the sample for impact resistance evaluation by about 5 mm more inward than the end edge. In this way, while maintaining the state where the metal rod was in contact with the end edge of the sample for impact resistance evaluation, the metal rod was pulled from the surface protective film of the sample for impact resistance evaluation toward the substrate. As a result, the end edge of the sample for impact resistance evaluation was rubbed with the metal rod. Then, the occurrence of adhesive defects from the end of the sample for impact resistance evaluation in the rubbed portion was observed using an optical microscope (differential interference microscope; manufactured by Nikon Corporation), and the impact resistance was evaluated according to the following criteria. Note that the "depth of the adhesive defect from the end edge" means the maximum distance in this direction of the adhesive sheet in which a defect has occurred from the end edge of the sample for impact resistance evaluation toward the inside in the plane direction in the portion where the adhesive sheet has a defect.

[0257] A: The depth of the adhesive defect from the end edge is less than 100 μm

[0258] B: The depth of the adhesive defect from the end edge is 100 μm or more

[0259] [Measurement of the thickness of the anchoring layer]

[0260] In each example and each comparative example, the retardation film with an anchoring layer was stained with a 2% ruthenium acid aqueous solution for 2 minutes to prepare a sample. Then, the sample was embedded in epoxy resin and cut into a thickness of about 80 nm by an ultramicrotome (Ultracut S, manufactured by LEICA) to prepare a film section for measurement. Next, the cross-section of the film section for measurement was observed using a TEM (Hitachi H-7650, acceleration voltage 100 kV). The "thickness of the anchoring layer" was set as the average value of the minimum thickness value of the anchoring layer obtained by measurement and the maximum thickness value of the anchoring layer obtained by measurement.

[0261] [Production of the optical laminate with a substrate]

[0262] (Example 1)

[0263] <Preparation of the adhesive composition>

[0264] In a reaction vessel equipped with a condenser tube, a nitrogen inlet tube, a thermometer, and a stirring device, 76.1 parts by weight of butyl acrylate, 0.1 part by weight of 4-hydroxybutyl acrylate, and 0.3 part by weight of 2,2-azobisisobutyronitrile relative to 100 parts by weight of the monomers (solid content) were added together with ethyl acetate, and the reaction was carried out at 60 °C for 4 hours under a nitrogen stream to prepare a reaction solution. Then, ethyl acetate was added to the reaction solution to obtain a polymer solution A containing an acrylic polymer having a weight average molecular weight of 2.2 million. Relative to 100 parts by weight of the solid content of the acrylic polymer solution A, 2.5 parts by weight of a trimethylolpropane / toluene diisocyanate adduct (manufactured by Mitsui Chemicals, Inc., trade name “Takenate D101E”), 0.04 part by weight of an epoxy group-containing silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM-403”), and 1 part by weight of a polyether compound having a reactive silyl group (manufactured by KANEKA Corporation, trade name “Silyl SAT10”) were blended to obtain an adhesive composition PSA1.

[0265] <Preparation of the anchor layer coating liquid>

[0266] A solution containing 50% by weight or more of a polyurethane polymer based on the solid content (manufactured by Nagase ChemteX Corporation, trade name “Denatron B-510C”) and a solution containing 10 to 70% by weight of an oxazoline group-containing acrylic polymer and 10 to 70% by weight of a methacrylate containing polyoxyethylene (manufactured by Nippon Shokubai Co., Ltd., trade name “Epocros WS-700”) were added to a mixed solvent containing 35% by weight of water and 65% by weight of isopropyl alcohol (IPA) to prepare an anchor layer coating liquid. The anchor layer coating liquid contains a polyurethane polymer, an oxazoline group-containing acrylic polymer, and a methacrylate containing polyoxyethylene as polymer C. In the anchor layer coating liquid, the weight part of the polyurethane polymer relative to 100 parts by weight of the mixed solvent is 0.017. In the anchor layer coating liquid, relative to 100 parts by weight of the mixed solvent, the total weight part of the oxazoline group-containing acrylic polymer and the weight part of the methacrylate containing polyoxyethylene is 0.033. In the anchor layer coating liquid, the weight part Wc of polymer C relative to 100 parts by weight of the mixed solvent is 0.05. oxazoline group-containing acrylic polymer, and a methacrylate containing polyoxyethylene as polymer C. In the anchor layer coating liquid, the weight part of the polyurethane polymer relative to 100 parts by weight of the mixed solvent is 0.017. In the anchor layer coating liquid, relative to 100 parts by weight of the mixed solvent, the total weight part of the oxazoline group-containing acrylic polymer and the weight part of the methacrylate containing polyoxyethylene is 0.033. In the anchor layer coating liquid, the weight part Wc of polymer C relative to 100 parts by weight of the mixed solvent is 0.05. oxazoline group-containing acrylic polymer, and a methacrylate containing polyoxyethylene as polymer C. In the anchor layer coating liquid, the weight part of the polyurethane polymer relative to 100 parts by weight of the mixed solvent is 0.017. In the anchor layer coating liquid, relative to 100 parts by weight of the mixed solvent, the total weight part of the oxazoline group-containing acrylic polymer and the weight part of the methacrylate containing polyoxyethylene is 0.033. In the anchor layer coating liquid, the weight part Wc of polymer C relative to 100 parts by weight of the mixed solvent is 0.05.

[0267] <Fabrication of the retardation film with an anchor layer>

[0268] The production of the retardation film with an anchoring layer was carried out by a roll-to-roll method. Plasma treatment (discharge amount: 5.83 kJ / m 2 ) was performed on one side of a retardation film (polycarbonate resin film, product name: Pureace RM-147) manufactured by Teijin Limited. Then, using a gravure coater, an anchoring layer coating liquid was coated on the plasma-treated side of the retardation film to form a coating film with a thickness of 5 μm. Then, the coating film was dried at 50 °C to produce a retardation film with an anchoring layer. The film was wound in a long strip.

[0269] <Fabrication of an optical laminate with a substrate>

[0270] Using a jet coater, the adhesive composition PSA1 was uniformly coated on the surface of a polyethylene terephthalate film (substrate) treated with a silicone-based release agent to obtain a coating film. Then, the coating film was dried in an air-circulation type constant temperature oven at 155 °C for 2 minutes to form an adhesive sheet on the surface of the substrate. The thickness of the adhesive sheet was 15 μm. The storage modulus G' of the adhesive sheet at 25 °C was 0.180 MPa.

[0271] Next, the adhesive sheet formed on the surface of the substrate was transferred to the surface of the retardation film with an anchoring layer where the anchoring layer was laminated to fabricate the optical laminate with a substrate of Example 1. In the optical laminate with a substrate, the substrate, the adhesive sheet, the anchoring layer, and the retardation film were laminated in sequence.

[0272] (Examples 2-9, Comparative Examples 1-5)

[0273] The conditions described in Table 1 were changed, and except for this, the optical laminates with a substrate of Examples 2-9 and Comparative Examples 1-5 were fabricated by the same method as in Example 1.

[0274] [Table 1]

[0275]

[0276] *Denatron B-510: Parts by weight of the polyurethane polymer relative to 100 parts by weight of the mixed solvent

[0277] *Epocros WS-700: Parts by weight of the oxazoline group-containing acrylic polymer and the total parts by weight of the methacrylate containing polyoxyethylene relative to 100 parts by weight of the mixed solvent And the total

[0278] As shown in Table 1, the optical laminates of the examples were excellent in impact resistance and adhesion compared with the optical laminates of the comparative examples.

[0279] Industrial Applicability

[0280] The optical laminate of the present invention can be used, for example, in an image display device.

Claims

1. An optical laminate, comprising: A retardation film containing a polycarbonate resin, An anchoring layer containing polymer C, and An adhesive sheet, In the optical laminate, the retardation film, the anchoring layer, and the adhesive sheet are laminated in this order, The thickness of the anchoring layer is 15 nm or more and 28 nm or less.

2. The optical laminate according to claim 1, wherein, The polymer C contains at least one selected from polyoxyalkylene-containing polymers and polyurethane polymers.

3. The optical laminate according to claim 1, wherein, The thickness of the anchoring layer is 15 nm or more and 23 nm or less.

4. The optical laminate according to claim 1, wherein, The storage modulus of the adhesive sheet at 25°C is 0.05 MPa or more.

5. The optical laminate according to claim 1, wherein, The storage modulus of the adhesive sheet at 25°C is 0.15 MPa or more.

6. An image display device, comprising: The optical laminate according to any one of claims 1 to 5, and An image forming layer.

7. A method for manufacturing an optical laminate, the optical laminate comprising a retardation film containing a polycarbonate resin, an anchoring layer containing polymer C, and an adhesive sheet, and in the optical laminate, the retardation film, the anchoring layer, and the adhesive sheet are laminated in this order, The manufacturing method includes: An anchoring layer coating liquid containing a solvent S containing an organic solvent and the polymer C is applied to the retardation film to form a coating film having a thickness of T (μm); and The coating film is dried. In the anchoring layer coating liquid, with respect to 100 parts by weight of the solvent S, the parts by weight Wc of the polymer C are 0.01 or more and 0.5 or less. The converted thickness of the coating film obtained by the following formula (1) is 2 μm or more and 10 μm or less. Converted thickness of the coating film = T × Wc / 0.1 (1).

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