Active energy ray-curable adhesive composition for optical film, and layered optical film

Abstract

This active energy ray-curable adhesive composition for an optical film contains vinyl methyl oxazolidinone. This active energy ray-curable adhesive composition for an optical film has excellent adhesiveness even when used for affixing an optical film having ultraviolet absorption ability.

Description

Active energy ray-curable adhesive composition for optical films and laminated optical films

[0001] The present invention relates to an active energy ray-curable adhesive composition for optical films and a laminated optical film.

[0002] Conventionally, dyed polyvinyl alcohol films (containing dichroic substances such as iodine and dichroic dyes) have been used as polarizers for various image display devices, such as liquid crystal display devices and organic EL display devices, because they have both high transmittance and high polarization degree. The polarizers are produced by subjecting a polyvinyl alcohol film to various treatments, such as dyeing, crosslinking, and stretching, in a bath (treatment bath), followed by drying. Furthermore, polarizers are typically used as polarizing films (polarizing plates) with an optical film, such as triacetyl cellulose, bonded to one or both sides of the polarizer using an adhesive.

[0003] As adhesives for optical films, aqueous adhesive compositions and active energy ray-curable adhesive compositions are widely used, and optical films having ultraviolet absorbing properties are sometimes used for the above-mentioned optical films. In such embodiments, Patent Document 1 discloses that a dry-and-solidify type adhesive such as an aqueous adhesive is suitable because an amount of ultraviolet light sufficient for curing the adhesive is absorbed by the optical film having ultraviolet absorbing properties.

[0004] Furthermore, Patent Document 2 describes that, from the viewpoint of productivity, since a drying step of the adhesive composition can be eliminated, an active energy ray-curable adhesive composition is preferable to an aqueous adhesive composition, and further proposes that in the above-mentioned embodiment, a visible light-curable adhesive composition containing a photopolymerization initiator that is highly sensitive to light of 380 nm or more be used.

[0005] JP 2022-44293 A JP 2022-58639 A

[0006] However, from the viewpoints of energy efficiency and productivity, there has been a demand for an active energy ray-curable adhesive composition for optical films that differs from the above-mentioned compositions.

[0007] In view of the above circumstances, an object of the present invention is to provide an active energy ray-curable adhesive composition for optical films that has excellent adhesive properties even when used to bond optical films that have ultraviolet absorbing properties.

[0008] Another object of the present invention is to provide a laminated optical film having an adhesive layer formed from the above-mentioned active energy ray-curable adhesive composition for optical films.

[0009] That is, the present invention relates to an active energy ray-curable adhesive composition for optical films, which contains vinylmethyloxazolidinone.

[0010] The active energy ray-curable adhesive composition for an optical film of the present invention preferably contains a cyclic ether group-containing (meth)acrylamide derivative.

[0011] In addition, in the active energy ray-curable adhesive composition for an optical film of the present invention, the mass ratio of the cyclic ether group-containing (meth)acrylamide derivative to vinylmethyloxazolidinone (cyclic ether group-containing (meth)acrylamide derivative / vinylmethyloxazolidinone) is preferably 2 or more and 10 or less.

[0012] The present invention also relates to a laminated optical film in which an optical film 1, an adhesive layer formed from the active energy ray-curable adhesive composition for optical films, and an optical film 2 are laminated in this order, and at least one of the optical films 1 and 2 is an optical film having ultraviolet absorbing ability.

[0013] In the laminated optical film of the present invention, the optical film having ultraviolet absorbing ability preferably has a transmittance of 10% or less for light of 380 nm.

[0014] In the laminated optical film of the present invention, the optical film 1 is preferably an optical film having ultraviolet absorbing ability, and the optical film 2 is preferably a polarizer.

[0015] In addition, in the laminated optical film of the present invention, the optical film having ultraviolet absorbing ability is a polycarbonate-based resin, and the polycarbonate-based resin is represented by formula (1): It is preferable that the copolymer contains a structural unit derived from a dihydroxy compound represented by the following formula:

[0016] Unlike conventional adhesive compositions, the active energy ray-curable adhesive composition for optical films of the present invention contains vinylmethyloxazolidinone, and therefore has excellent adhesive properties even when used to bond optical films that have ultraviolet absorbing ability.

[0017] <Active Energy Ray-Curable Adhesive Composition for Optical Film> The active energy ray-curable adhesive composition for an optical film of the present invention (hereinafter also simply referred to as "adhesive composition") contains vinylmethyloxazolidinone (also referred to as 5-methyl-3-vinyloxazolidin-2-one).

[0018] The active energy ray-curable adhesive composition for optical films can be broadly classified into electron beam-curable, ultraviolet ray-curable, and visible light-curable adhesive compositions. Furthermore, the curing mode can be classified into radically polymerizable curable adhesive compositions and cationically polymerizable adhesive compositions. In the present invention, active energy rays with a wavelength range of 10 nm to less than 380 nm are referred to as ultraviolet rays, and active energy rays with a wavelength range of 380 nm to 800 nm are referred to as visible light.

[0019] <Radical Polymerizable Compound> The radical polymerizable compound used in the adhesive composition includes the above-mentioned vinylmethyloxazolidinone, as well as compounds having a radically polymerizable functional group of a carbon-carbon double bond, such as a (meth)acryloyl group or a vinyl group. These curable components can be either monofunctional radically polymerizable compounds or polyfunctional radically polymerizable compounds having two or more functional groups. These radically polymerizable compounds can be used alone or in combination of two or more. Suitable examples of these radically polymerizable compounds include compounds having a (meth)acryloyl group. In the present invention, (meth)acryloyl refers to an acryloyl group and / or a methacryloyl group, and "(meth)" has the same meaning hereinafter.

[0020] <Monofunctional radical polymerizable compound> Examples of the monofunctional radical polymerizable compound include compounds represented by the formula (2): (In formula (2), R １ is a hydrogen atom or a methyl group, and R ２ and R ３ are each independently a hydrogen atom, an alkyl group, a hydroxyalkyl group, an alkoxyalkyl group, or a cyclic ether group, and R ２ and R ３ may form a cyclic heterocycle.) The number of carbon atoms in the alkyl moiety of the alkyl group, hydroxyalkyl group, and / or alkoxyalkyl group is not particularly limited, but examples include those having 1 to 4 carbon atoms. ２ and R ３ Examples of the cyclic heterocycle that may be formed include N-acryloylmorpholine.

[0021] Specific examples of the compound represented by the above formula (2) include N-alkyl group-containing (meth)acrylamide derivatives such as N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-isopropyl(meth)acrylamide, N-butyl(meth)acrylamide, and N-hexyl(meth)acrylamide; N-hydroxyalkyl group-containing (meth)acrylamide derivatives such as N-methylol(meth)acrylamide, N-hydroxyethyl(meth)acrylamide, and N-methylol-N-propane(meth)acrylamide; and N-alkoxy group-containing (meth)acrylamide derivatives such as N-methoxymethylacrylamide and N-ethoxymethylacrylamide. Examples of the cyclic ether group-containing (meth)acrylamide derivative include heterocycle-containing (meth)acrylamide derivatives in which the nitrogen atom of the (meth)acrylamide group forms a heterocycle, such as N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine, etc. Among these, cyclic ether group-containing (meth)acrylamide derivatives are preferred, and N-hydroxyethylacrylamide and N-acryloylmorpholine are particularly preferred, in terms of excellent reactivity, ability to obtain a cured product with a high elastic modulus, and excellent adhesion to polarizers.

[0022] In the radical polymerizable compound, the proportion of vinylmethyloxazolidinone is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 8% by mass or more, from the viewpoint of adhesiveness, and is preferably 50% by mass or less, more preferably 40% by mass or more, and even more preferably 30% by mass or less, from the viewpoint of adhesiveness.

[0023] Furthermore, when a compound represented by the above formula (2) is used, the proportion of the above formula (2) in the radical polymerizable compound is preferably 30% by mass or more, more preferably 35% by mass or more, and even more preferably 45% by mass or more, from the viewpoint of adhesiveness, and is preferably 90% by mass or less, more preferably 80% by mass or more, and even more preferably 75% by mass or less, from the viewpoint of adhesiveness.

[0024] Furthermore, when the compound represented by the above formula (2) is used, the mass ratio of the compound represented by the above formula (2) (e.g., a cyclic ether group-containing (meth)acrylamide derivative) to vinylmethyloxazolidinone (compound represented by the formula (2) (e.g., a cyclic ether group-containing (meth)acrylamide derivative) / vinylmethyloxazolidinone) is preferably 1 or more, more preferably 2 or more, from the viewpoint of adhesiveness, and is preferably 10 or less, more preferably 8 or less, from the viewpoint of adhesiveness.

[0025]

[0033] In addition to the compounds described above, the active energy ray-curable adhesive composition for an optical film may contain, as a curable component, other monofunctional radical polymerizable compounds, from the viewpoint of enabling the adhesive composition to exhibit various functions. Examples of the other monofunctional radical polymerizable compounds include various (meth)acrylic acid derivatives having a (meth)acryloyloxy group. Specific examples include (meth)acrylic acid (C1-20) alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate, 2-methyl-2-nitropropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, s-butyl (meth)acrylate, t-butyl (meth)acrylate, n-pentyl (meth)acrylate, t-pentyl (meth)acrylate, 3-pentyl (meth)acrylate, 2,2-dimethylbutyl (meth)acrylate, n-hexyl (meth)acrylate, cetyl (meth)acrylate, n-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, 4-methyl-2-propylpentyl (meth)acrylate, and n-octadecyl (meth)acrylate.

[0026] Examples of the (meth)acrylic acid derivatives include cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate and cyclopentyl (meth)acrylate; aralkyl (meth)acrylates such as benzyl (meth)acrylate; 2-isobornyl (meth)acrylate, 2-norbornylmethyl (meth)acrylate, 5-norbornen-2-yl-methyl (meth)acrylate, 3-methyl-2-norbornylmethyl (meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyl methyl (meth)acrylate, and methyl ... Examples of the alkoxy group- or phenoxy group-containing (meth)acrylates include polycyclic (meth)acrylates such as 2-methoxyethyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxymethoxyethyl (meth)acrylate, 3-methoxybutyl (meth)acrylate, ethyl carbitol (meth)acrylate, phenoxyethyl (meth)acrylate, and alkylphenoxy polyethylene glycol (meth)acrylate.

[0027] Examples of the (meth)acrylic acid derivatives include hydroxyalkyl (meth)acrylates such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate. (meth)acrylate, hydroxyl group-containing (meth)acrylates such as [4-(hydroxymethyl)cyclohexyl]methyl acrylate, cyclohexanedimethanol mono(meth)acrylate, and 2-hydroxy-3-phenoxypropyl (meth)acrylate; epoxy group-containing (meth)acrylates such as glycidyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate glycidyl ether; 2,2,2-trifluoroethyl (meth)acrylate, 2,2,2-trifluoroethylethyl (meth)acrylate; ) acrylate, tetrafluoropropyl (meth)acrylate, hexafluoropropyl (meth)acrylate, octafluoropentyl (meth)acrylate, heptadecafluorodecyl (meth)acrylate, 3-chloro-2-hydroxypropyl (meth)acrylate and other halogen-containing (meth)acrylates; alkylaminoalkyl (meth)acrylates such as dimethylaminoethyl (meth)acrylate; 3-oxetanylmethyl (meth)acrylate, 3-methyl-oxetanylmethyl (meth) acrylate, 3-ethyl-oxetanylmethyl (meth)acrylate, 3-butyl-oxetanylmethyl (meth)acrylate, 3-hexyl-oxetanylmethyl (meth)acrylate and other oxetane group-containing (meth)acrylates; (meth)acrylates having a heterocycle such as tetrahydrofurfuryl (meth)acrylate and butyrolactone (meth)acrylate; hydroxypivalic acid neopentyl glycol (meth)acrylic acid adduct; and p-phenylphenol (meth)acrylate.

[0028] Other monofunctional radically polymerizable compounds include carboxyl group-containing monomers such as (meth)acrylic acid, carboxyethyl acrylate, carboxypentyl acrylate, itaconic acid, maleic acid, fumaric acid, crotonic acid, and isocrotonic acid.

[0029] Furthermore, other monofunctional radically polymerizable compounds include, for example, lactam vinyl monomers such as N-vinylpyrrolidone, N-vinyl-ε-caprolactam, and methylvinylpyrrolidone; and vinyl monomers having a nitrogen-containing heterocycle such as vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, and vinylmorpholine.

[0030] In addition, as another monofunctional radical polymerizable compound, a radical polymerizable compound having an active methylene group can be used. The radical polymerizable compound having an active methylene group is a compound having an active double bond group such as a (meth)acrylic group at the end or in the molecule, and also having an active methylene group. Examples of the active methylene group include an acetoacetyl group, an alkoxymalonyl group, and a cyanoacetyl group. It is preferable that the active methylene group is an acetoacetyl group. Specific examples of the radically polymerizable compound having an active methylene group include acetoacetoxyalkyl (meth)acrylates such as 2-acetoacetoxyethyl (meth)acrylate, 2-acetoacetoxypropyl (meth)acrylate, and 2-acetoacetoxy-1-methylethyl (meth)acrylate; 2-ethoxymalonyloxyethyl (meth)acrylate, 2-cyanoacetoxyethyl (meth)acrylate, N-(2-cyanoacetoxyethyl)acrylamide, N-(2-propionylacetoxybutyl)acrylamide, N-(4-acetoacetoxymethylbenzyl)acrylamide, and N-(2-acetoacetylaminoethyl)acrylamide.

[0031] When the other monofunctional radical polymerizable compound is used, the proportion of the other monofunctional radical polymerizable compound in the radical polymerizable compound is usually about 30% by mass or less.

[0032] <Difunctional or More Polyfunctional Radically Polymerizable Compound> Examples of the difunctional or more polyfunctional radically polymerizable compound include polyfunctional (meth)acrylamide derivatives such as N,N'-methylenebis(meth)acrylamide, tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, 1,10-decanediol diacrylate, 2-ethyl-2-butylpropanediol di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol A ethylene oxide adduct di(meth)acrylate, bisphenol A propylene oxide adduct di(meth)acrylate, bisphenol A diglycidyl ether di(meth)acrylate, neo Examples of the ester include esters of (meth)acrylic acid and polyhydric alcohols such as pentyl glycol di(meth)acrylate, dimethylol-tricyclodecane diacrylate, dimethyloldicyclopentane diacrylate, cyclic trimethylolpropane formal (meth)acrylate, dioxane glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, and EO-modified diglycerin tetra(meth)acrylate; and 9,9-bis[4-(2-(meth)acryloyloxyethoxy)phenyl]fluorene. Commercially available products include Aronix M-220 (manufactured by Toagosei Co., Ltd.), Light Acrylate 1,9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), Light Acrylate DGE-4A (manufactured by Kyoeisha Chemical Co., Ltd.), Light Acrylate DCP-A (manufactured by Kyoeisha Chemical Co., Ltd.), SR-531 (manufactured by Sartomer Co., Ltd.), CD-536 (manufactured by Sartomer Co., Ltd.), etc. Furthermore, various epoxy (meth)acrylates, urethane (meth)acrylates, polyester (meth)acrylates, various (meth)acrylate monomers, etc. may also be used, if necessary.Among these, from the viewpoint of affinity with the adherend, bifunctional radically polymerizable compounds having an alicyclic structure, such as dimethyloltricyclodecane diacrylate and dimethyloldicyclopentane diacrylate, are preferred.

[0033] From the viewpoint of achieving both adhesion to the optical film and optical durability under harsh environments, it is preferable to use a combination of a monofunctional radically polymerizable compound and a polyfunctional radically polymerizable compound as the radically polymerizable compound. Since the monofunctional radically polymerizable compound has a relatively low liquid viscosity, its inclusion in the adhesive composition can reduce the liquid viscosity of the adhesive composition. Furthermore, it is preferable to include a polyfunctional radically polymerizable compound in the adhesive composition because it can three-dimensionally crosslink the cured product of the adhesive composition. When the polyfunctional radically polymerizable compound is used, the proportion of the polyfunctional radically polymerizable compound in the radically polymerizable compound is preferably 5% by mass or more and 40% by mass or less, and more preferably 10% by mass or more and 30% by mass or less.

[0034] When ultraviolet light or visible light is used as the active energy ray, the active energy ray-curable adhesive composition for optical films preferably contains a photopolymerization initiator.

[0035] <Photopolymerization initiator> The photopolymerization initiator is appropriately selected depending on the active energy ray. When curing is performed with ultraviolet light or visible light, a photopolymerization initiator that is cleaved by ultraviolet light or visible light is used. Examples of the photopolymerization initiator include benzophenone-based compounds such as benzil, benzophenone, benzoylbenzoic acid, and 3,3'-dimethyl-4-methoxybenzophenone; aromatic ketone compounds such as 4-(2-hydroxyethoxy)phenyl(2-hydroxy-2-propyl)ketone, α-hydroxy-α,α'-dimethylacetophenone, 2-methyl-2-hydroxypropiophenone, and α-hydroxycyclohexylphenyl ketone; acetophenone-based compounds such as methoxyacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxyacetophenone, and 2-methyl-1-[4-(methylthio)-phenyl]-2-morpholinopropane-1; benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin methyl ether. aromatic sulfonyl chloride compounds such as 2-naphthalenesulfonyl chloride; photoactive oxime compounds such as 1-phenone-1,1-propanedione-2-(o-ethoxycarbonyl)oxime; thioxanthone compounds such as thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, 2,4-dimethylthioxanthone, isopropylthioxanthone, 2,4-dichlorothioxanthone, 2,4-diethylthioxanthone, 2,4-diisopropylthioxanthone, and dodecylthioxanthone; camphorquinone; halogenated ketones; acylphosphinoxides; and acylphosphonates.

[0036] Furthermore, since an optical film having ultraviolet absorption ability used for bonding the adhesive composition has difficulty transmitting light of 380 nm or less, the adhesive composition is preferably used as a visible light curable adhesive composition. In this case, the photopolymerization initiator is preferably a compound represented by the formula (3): (In formula (3), R ４ and R ５ are independently —H, —CH ２ CH ３, -iPr or Cl), and / or a compound represented by formula (4): (In formula (4), R ６ , R ７ and R ８ are independently —H, —CH ３ , -CH ２ CH ３ , -iPr or Cl. Among the compounds represented by formula (3), it is preferable that R ４ and R ５ Ga-CH ２ CH ３ Diethylthioxanthone, which is represented by the formula (4), is preferred. A commercially available example of the compound represented by formula (4) is 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one (trade name: Omnirad907, manufacturer: IGM Resins). From the viewpoint of sensitivity, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butanone-1 (trade name: Omnirad369, manufacturer: IGM Resins) and 2-(dimethylamino)-2-[(4-methylphenyl)methyl]-1-[4-(4-morpholinyl)phenyl]-1-butanone (trade name: Omnirad379, manufacturer: IGM Resins) are preferred.

[0037] Examples of the photopolymerization initiator highly sensitive to light of 380 nm or more include 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide, bis(η5-2,4-cyclopentadien-1-yl)-bis(2,6-difluoro-3-(1H-pyrrol-1-yl)-phenyl)titanium, and the like.

[0038] Examples of the photopolymerization initiator include oxime ester photopolymerization initiators such as those described in JP 2000-80068 A, JP 2001-233842 A, JP 2010-527339 A, JP 2010-527338 A, JP 2013-041153 A, and WO 2015 / 036910. Specific examples of such compounds include 1,2-octanedione, 1-4-(phenylthio)-2-(O-benzoyloxime), ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyloxime), and the like. In addition, commercially available products include compounds having a carbazole skeleton, such as Irgacure OXE-02 (manufactured by BASF), Adeka Arcles NCI-831 (manufactured by ADEKA Corporation), N-1919 (manufactured by ADEKA Corporation), and TR-PBG-304 (manufactured by Changzhou Powerful Electronic New Materials Co., Ltd.); compounds having a diphenyl sulfide skeleton, such as Irgacure OXE-01 (manufactured by BASF), Adeka Arcles NCI-930 (manufactured by ADEKA Corporation), TR-PBG-345 (manufactured by Changzhou Powerful Electronic New Materials Co., Ltd.), and TR-PBG-3057 (manufactured by Changzhou Powerful Electronic New Materials Co., Ltd.); and compounds having a fluorene skeleton, such as TR-PBG-365 (manufactured by Changzhou Powerful Electronic New Materials Co., Ltd.).

[0039] The amount of the photopolymerization initiator may be appropriately set and is, for example, usually 20 parts by mass or less relative to 100 parts by mass of the radical polymerizable compound. The amount of the photopolymerization initiator is preferably 1 to 15 parts by mass, more preferably 3 to 10 parts by mass, relative to 100 parts by mass of the radical polymerizable compound.

[0040] Furthermore, a polymerization initiation aid may be added as necessary. Examples of the polymerization initiation aid include triethylamine, diethylamine, N-methyldiethanolamine, ethanolamine, 4-dimethylaminobenzoic acid, methyl 4-dimethylaminobenzoate, ethyl 4-dimethylaminobenzoate, and isoamyl 4-dimethylaminobenzoate. When a polymerization initiation aid is used, the amount added is usually about 5 parts by mass or less per 100 parts by mass of the adhesive composition.

[0041] Furthermore, when a radical polymerizable compound having an active methylene group is used as the radical polymerizable compound, it is preferable to use it in combination with a radical polymerization initiator having a hydrogen abstracting effect. This configuration significantly improves the adhesiveness of the adhesive layer of the polarized film, especially immediately after removal from a high-humidity environment or water (non-dried state). Examples of the radical polymerization initiator having a hydrogen abstracting effect include thioxanthone-based radical polymerization initiators and benzophenone-based radical polymerization initiators. The radical polymerization initiator is preferably a thioxanthone-based radical polymerization initiator. Examples of the thioxanthone-based radical polymerization initiator include the compound represented by the above formula (3).

[0042] The active energy ray-curable adhesive composition for optical films may contain various additives as other optional components within a range that does not impair the objects and effects of the present invention. Examples of such additives include polymers such as chlorinated polyolefins, epoxy resins, polyamides, polyamideimides, polyurethanes, polybutadiene, polychloroprene, polyethers, polyesters, styrene-butadiene block copolymers, petroleum resins, xylene resins, ketone resins, and cellulose resins; oligomers such as acrylic oligomers, fluorine-containing oligomers, silicone oligomers, and polysulfide oligomers; sensitizers, photoacid generators, photobase generators, silane coupling agents, polyrotaxanes, organometallic compounds, polymerization inhibitors, bubble suppressors, surfactants, plasticizers, UV absorbers, inorganic fillers, pigments, and dyes.

[0043] <Laminated Optical Film> The laminated optical film of the present invention comprises an optical film 1, an adhesive layer formed from the active energy ray-curable adhesive composition for an optical film, and an optical film 2 laminated in this order, and at least one of the optical films 1 and 2 is an optical film having ultraviolet absorbing ability. The optical films 1 and 2 may be the same or different. Hereinafter, the optical films 1 and 2 will also be collectively referred to simply as "optical films."

[0044] The optical film having ultraviolet absorbing ability preferably has a transmittance of 20% or less, more preferably 10% or less, for light of 380 nm, from the viewpoint of protecting polarizers, liquid crystals, etc. from ultraviolet rays when the laminated optical film is incorporated into various image display devices. To impart ultraviolet absorbing ability to the optical film, for example, the material constituting the optical film may have ultraviolet absorbing ability, an ultraviolet absorber or the like may be added to the material constituting the optical film, or a surface treatment layer containing an ultraviolet absorber or the like may be laminated on the surface of the optical film.

[0045] Examples of the ultraviolet absorber include conventionally known oxybenzophenone compounds, benzotriazole compounds, salicylate ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex salt compounds, triazine compounds, etc. Commercially available products include Adekastab LA-46 (manufactured by ADEKA Corporation), Adekastab LA-F70 (manufactured by ADEKA Corporation), KEMISORB102 (manufactured by Chemipro Chemicals), Chiguard 5405 (manufactured by Chitec Technology), Tinuvin 405 (manufactured by BASF Corporation), Tinuvin 460 (manufactured by BASF Corporation), Tinuvin 479 (manufactured by BASF Corporation), and Tinuvin 1600 (manufactured by BASF Corporation).

[0046] In the laminated optical film, from the viewpoint of adhesiveness, the HSP distance (Ra-1 described below) between the HSP of the active energy ray-curable adhesive composition for optical films and the HSP of the optical film having ultraviolet absorbing ability is preferably 0.5 or more, more preferably 1 or more, and is preferably 10 or less, more preferably 5 or less. Methods for measuring the HSP of the adhesive composition and optical film will be described later.

[0047] The optical films 1 and 2 are not particularly limited, and various transparent protective films used in various image display devices can be used. Examples of materials that can be used to form the transparent protective film include thermoplastic resins that are excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, and isotropy. Examples of thermoplastic resins include cellulose ester resins such as triacetyl cellulose, polyester resins such as polyethylene terephthalate and polyethylene naphthalate, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins such as nylon and aromatic polyamide, polyimide resins, polyolefin resins such as polyethylene, polypropylene, and ethylene-propylene copolymers, (meth)acrylic resins, cyclic polyolefin resins (norbornene resins) having a cyclo- or norbornene structure, polyarylate resins, polystyrene resins, polyvinyl alcohol resins, and mixtures thereof. The transparent protective film can also be a cured layer formed from a thermosetting resin or ultraviolet-curable resin, such as a (meth)acrylic, urethane, acrylic urethane, epoxy, or silicone resin. Among these, cellulose ester resins, polycarbonate resins, (meth)acrylic resins, cyclic polyolefin resins, and polyester resins are suitable. The transparent protective film may contain any appropriate additives such as an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a coloring inhibitor, a flame retardant, an antistatic agent, a pigment, and a colorant.

[0048] The polycarbonate resin usually has at least one bond structure -CH ２ The polycarbonate resin is produced by reacting a dihydroxy compound having —O— with a carbonic acid diester in the presence of a polymerization catalyst. Preferably, the dihydroxy compound contains a structural unit derived from a dihydroxy compound represented by the following formula: Examples of such dihydroxy compounds include isosorbide, isomannide, and isoidet, which are stereoisomers. These may be used alone or in combination of two or more.

[0049] The polycarbonate resin may further contain structural units derived from dihydroxy compounds other than the dihydroxy compound represented by formula (1) (hereinafter, also simply referred to as "other dihydroxy compounds"). By further containing structural units derived from dihydroxy compounds other than the dihydroxy compound represented by formula (1), it becomes possible to improve ease of processing, heat resistance, impact resistance, etc.

[0050] Examples of other dihydroxy compounds include alicyclic dihydroxy compounds, aliphatic dihydroxy compounds, oxyalkylene glycols, aromatic dihydroxy compounds, and diols having a cyclic ether structure.

[0051] The alicyclic dihydroxy compound is not particularly limited, and is preferably a compound having a five-membered ring structure or a six-membered ring structure. The six-membered ring structure may be fixed into a chair or boat shape by a covalent bond. When the alicyclic dihydroxy compound has a five-membered ring structure or a six-membered ring structure, the heat resistance of the resulting polycarbonate can be improved. Examples of the alicyclic dihydroxy compound include cyclohexanedimethanols, tricyclodecane dimethanols, adamantanediols, and pentacyclopentadecanedimethanols. From the viewpoints of availability and ease of handling, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,2-cyclohexanedimethanol, and tricyclodecane dimethanol are preferred.

[0052] Examples of the aliphatic dihydroxy compounds include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,4-butanediol, 1,3-butanediol, 1,2-butanediol, 1,5-heptanediol, and 1,6-hexanediol. Examples of the oxyalkylene glycols include diethylene glycol, triethylene glycol, tetraethylene glycol, and polyethylene glycol. Examples of the aromatic dihydroxy compounds include 2,2-bis(4-hydroxyphenyl)propane [=bisphenol A], 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 2,2-bis(4-hydroxy-3,5-diethylphenyl)propane, and 2,2-bis(4-hydroxy-(3,5-diphenyl)phenyl)propane. Examples of the diols having a cyclic ether structure include spiroglycols and dioxane glycols.

[0053] The proportion of the dihydroxy compound represented by formula (1) relative to all dihydroxy compounds constituting the polycarbonate resin is not particularly limited, but is preferably 10 mol% or more, more preferably 40 mol% or more, even more preferably 60 mol% or more, preferably 90 mol% or less, more preferably 80 mol% or less, and even more preferably 70 mol% or less. If the content of structural units derived from other dihydroxy compounds is too high, performance such as optical properties may be reduced.

[0054] When an alicyclic dihydroxy compound is used among the other dihydroxy compounds, the total proportion of the dihydroxy compound represented by formula (1) and the alicyclic dihydroxy compound relative to all dihydroxy compounds constituting the polycarbonate is not particularly limited, but is preferably 80 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more.

[0055] The thickness of the transparent protective film can be determined as appropriate. In general, from the viewpoints of strength, workability such as handleability, thinness, etc., the thickness is preferably about 1 to 500 μm, more preferably about 1 to 300 μm, and even more preferably about 5 to 100 μm.

[0056] When the laminated optical film is used as a polarizing film, it is preferable that the optical film 1 is an optical film having the above-mentioned ultraviolet absorbing ability, and the optical film 2 is a polarizer. The polarizer may be a known polarizer formed by adsorbing and orienting a dichroic substance such as iodine or a dichroic dye on a polyvinyl alcohol-based film.

[0057] The transparent protective film can be a retardation plate having a front retardation of 40 nm or more and / or a thickness retardation of 80 nm or more. The front retardation is usually controlled to be in the range of 40 to 200 nm, and the thickness retardation is usually controlled to be in the range of 80 to 300 nm. When a retardation plate is used as the transparent protective film, the retardation plate also functions as the transparent protective film, thereby enabling a thinner film to be achieved.

[0058] Examples of the retardation plate include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, an oriented film of a liquid crystal polymer, and an oriented layer of a liquid crystal polymer supported by a film. The thickness of the retardation plate is not particularly limited, but is generally about 20 to 150 μm. The retardation plate may be used by being attached to a transparent protective film that does not have a retardation.

[0059] In the polarizing film, a functional layer such as a hard coat layer, an anti-reflection layer, an anti-sticking layer, a diffusion layer, an anti-glare layer, etc. may be provided on the surface of the transparent protective film to which the polarizer is not attached. The functional layer such as the hard coat layer, the anti-reflection layer, the anti-sticking layer, the diffusion layer, or the anti-glare layer may be provided on the protective film itself, or may be provided separately from the protective film.

[0060] In the laminated optical film, an active energy ray-curable adhesive composition for optical films is applied directly to optical film 1 and / or optical film 2, and after the optical films 1 and 2 are bonded together, the adhesive composition is irradiated with active energy rays (electron beams, ultraviolet rays, visible light, etc.) to cure the adhesive composition and form an adhesive layer. The active energy rays can be irradiated from any appropriate direction. However, since the active energy ray-curable adhesive composition for optical films of the present invention has excellent adhesive properties even when used to bond an optical film having ultraviolet absorption ability, it may be irradiated from the optical film side having ultraviolet absorption ability. In addition, in a polarized film (in an embodiment in which optical film 1 is an optical film having ultraviolet absorption ability and optical film 2 is a polarizer), irradiation from the polarizer side may cause degradation of the polarizer due to active energy rays. Therefore, the active energy ray-curable adhesive composition for optical films of the present invention is useful because it can be irradiated from the optical film side having ultraviolet absorption ability.

[0061] The method for applying the adhesive composition is appropriately selected depending on the viscosity of the composition and the desired thickness, and examples thereof include a reverse coater, a gravure coater (direct, reverse, or offset), a bar reverse coater, a roll coater, a die coater, a bar coater, and a rod coater.

[0062] In the laminated optical film, any appropriate conditions may be adopted as the irradiation conditions of the active energy rays as long as the conditions are conditions under which the adhesive composition can be cured. For example, when ultraviolet rays or visible light are used as the active energy rays, the illuminance in the wavelength range of 395 to 445 nm is 200 to 2000 mW / cm ２ , the cumulative light amount is 100 to 1500 mJ / cm ２ That's about it.

[0063] From the viewpoint of productivity and adhesiveness, the thickness of the adhesive layer is preferably about 0.1 to 100 μm, more preferably about 0.3 to 10 μm, and even more preferably about 0.5 to 5 μm.

[0064] In the laminated optical film, the optical film 1 and the optical film 2 may be laminated via an intervening layer such as a surface modification layer, an easy-adhesive layer, a blocking layer, or a refractive index adjustment layer.

[0065] Examples of the surface modification treatment for forming the surface modification layer include corona treatment, plasma treatment, primer treatment, and saponification treatment.

[0066] Examples of the easy-adhesion adhesive that forms the easy-adhesion layer include forming materials containing various resins having a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone-based skeleton, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, or the like.

[0067] The blocking layer is a layer having a function of preventing impurities such as oligomers and ions eluted from an optical film, etc., from migrating (penetrating) into an optical film such as a polarizer. The blocking layer may be any layer as long as it is transparent and can prevent impurities from eluting from an optical film, etc. Examples of materials for forming the blocking layer include urethane prepolymer-based forming materials, cyanoacrylate-based forming materials, and epoxy-based forming materials.

[0068] The refractive index adjusting layer is a layer provided to suppress a decrease in transmittance due to reflection between layers having different refractive indices in the optical film. Examples of the refractive index adjusting material for forming the refractive index adjusting layer include forming agents containing various resins such as silica-based, acrylic-based, acrylic-styrene-based, and melamine-based resins and additives.

[0069] An adhesive layer for bonding other members may be provided on one or both surfaces of the laminated optical film. A pressure-sensitive adhesive layer is suitable as the adhesive layer. The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is not particularly limited, and can be appropriately selected and used from, for example, a pressure-sensitive adhesive having an acrylic polymer, a silicone polymer, a polyester, a polyurethane, a polyamide, a polyether, a fluorine-based polymer, a rubber-based polymer, or the like as a base polymer. In particular, a pressure-sensitive adhesive having excellent optical transparency, moderate wettability, cohesion, and adhesive properties, and excellent weather resistance, heat resistance, etc., such as a pressure-sensitive adhesive containing an acrylic polymer, is preferably used.

[0070] The application of the pressure-sensitive adhesive layer to one or both surfaces of the laminated optical film can be performed by any suitable method. Examples of application of the pressure-sensitive adhesive layer include preparing a pressure-sensitive adhesive solution and applying it directly to the laminated optical film by a suitable application method such as a casting method or a coating method, or forming a pressure-sensitive adhesive layer on a separator and transferring it onto the laminated optical film. The thickness of the pressure-sensitive adhesive layer can be determined appropriately depending on the intended use, adhesive strength, etc., and is generally 1 to 500 μm, preferably 5 to 200 μm, and more preferably 10 to 100 μm. A laminated optical film having a pressure-sensitive adhesive layer provided on at least one surface thereof is also referred to as a pressure-sensitive adhesive layer-attached laminated optical film.

[0071] It is preferable that a separator be temporarily attached to cover the exposed surface of the pressure-sensitive adhesive layer to prevent contamination, etc., until the product is put into practical use. This prevents contamination, etc., of the pressure-sensitive adhesive layer under normal handling conditions. Examples of the separator include suitable thin sheets such as plastic films, rubber sheets, paper, cloth, nonwoven fabrics, nets, foam sheets, metal foils, and laminates thereof, which are coated with a suitable release agent, such as a silicone-based, long-chain alkyl-based, fluorine-based, or molybdenum sulfide-based release agent, as needed.

[0072] The laminated optical film can be used in various image display devices such as liquid crystal display devices and organic EL display devices.

[0073] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0074] Examples 1-4, Comparative Example 1 Preparation of Adhesive Composition In each Example and Comparative Example, the following components were mixed in the amounts shown in Table 1 at 25°C for 1 hour to prepare an adhesive composition (the units of blending amounts shown in Table 1 are relative parts by mass). ACMO: N-acryloylmorpholine, manufactured by KJ Chemicals DCP-A: dimethylol-tricyclodecane diacrylate, manufactured by Kyoeisha Chemical Co., Ltd. VMOX: vinylmethyloxazolidinone (5-methyl-3-vinyloxazolidin-2-one, manufactured by BASF Corporation Omnirad 907: 2-methyl-1-(4-methylthiophenyl)-2-morpholinopropan-1-one, manufactured by IGM Resins DETX-S: "KAYACURE DETX-S", 2,4-diethylthioxanthone, manufactured by Nippon Kayaku Co., Ltd.

[0075] <Preparation of Optical Film with UV Absorption Ability> 81.98 parts by mass of isosorbide, 47.19 parts by mass of tricyclodecane dimethanol, 175.1 parts by mass of diphenyl carbonate, and 0.979 parts by mass of a 0.2% by mass aqueous solution of cesium carbonate as a catalyst were charged into a reaction vessel. In a nitrogen atmosphere, the heating bath temperature was heated to 150°C as the first step of the reaction, and the raw materials were dissolved (approximately 15 minutes) with stirring as necessary. Next, the pressure was increased from atmospheric pressure to 13.3 kPa, and the heating bath temperature was increased to 190°C over 1 hour, while the generated phenol was extracted from the reaction vessel. After the entire reaction vessel was held at 190°C for 15 minutes, the pressure inside the reaction vessel was increased to 6.67 kPa, and the heating bath temperature was increased to 230°C over 15 minutes as the second step, and the generated phenol was extracted from the reaction vessel. As the stirring torque of the stirrer increased, the temperature was raised to 250°C in 8 minutes. Furthermore, to remove the generated phenol, the pressure inside the reaction vessel was reduced to 0.200 kPa or less. After reaching the predetermined stirring torque, the reaction was terminated, and the resulting reaction product was extruded into water to obtain polycarbonate-based resin pellets. Subsequently, ADK STAB LA-F70 was added as a UV absorber to obtain polycarbonate-based resin pellets with UV absorption capabilities. The resulting UV-absorbed polycarbonate-based resin was vacuum-dried at 80°C for 5 hours, and then an optical film composed of the polycarbonate-based resin was produced using a film-forming device equipped with a single-screw extruder (manufactured by Toshiba Machine Co., Ltd., cylinder set temperature: 250°C), a T-die (width: 300 mm, set temperature: 250°C), a chill roll (set temperature: 120-130°C), and a winder. The resulting optical film had a thickness of 20 μm.

[0076] <Preparation of Polarizer> A laminate having a 9 μm-thick PVA layer formed on an amorphous PET substrate was subjected to auxiliary in-air stretching at a stretching temperature of 130°C to produce a stretched laminate, the stretched laminate was then dyed to produce a dyed laminate, and the dyed laminate was further stretched integrally with the amorphous PET substrate by stretching in boric acid water at a stretching temperature of 65°C to produce an optical film laminate including a 5 μm-thick PVA layer so that the total stretch ratio was 5.94 times. This two-stage stretching resulted in highly oriented PVA molecules in the PVA layer formed on the amorphous PET substrate, and iodine adsorbed by dyeing was highly oriented in one direction as a polyiodine ion complex, thereby producing an optical film laminate (hereinafter referred to as a polarizer) including a 5 μm-thick PVA layer (thin polarizer) constituting an iodine-based thin polarizer.

[0077] <Preparation of Laminated Optical Film> The adhesive composition was applied to the optical film composed of the polycarbonate-based resin obtained above and to the polarizer so that the total film thickness after curing was 1.0 μm. For coating, an MCD coater (manufactured by Fuji Machine Co., Ltd.) (cell shape: honeycomb, gravure roll line count: 1000 / inch, rotation speed: 140% / line speed) was used. Next, the optical film and the polarizer were bonded together via the adhesive-coated surface. Next, the adhesive composition between the films was cured by irradiating ultraviolet light from the optical film side of the obtained laminate, thereby obtaining a laminated optical film. For ultraviolet irradiation, a gallium lamp was used, and the illuminance in the wavelength range of 395 to 445 nm was 1000 mW / cm. ２ , the cumulative light amount is 600 mJ / cm ２ It was adjusted so that

[0078] <Evaluation of Adhesion> A sample film measuring 200 mm on a first side and 15 mm on a second side was cut out from the laminated optical film. The first side was the side extending in the stretching direction of the polarizer. The second side was the side extending in a direction perpendicular to the stretching direction. Next, the optical film side of the sample film made of polycarbonate resin was attached to a glass plate via a strong adhesive. Next, the 90° peel strength (N / 15 mm) of the optical film from the laminated optical film was measured using a Tensilon universal testing machine (product name "RTC", manufactured by A&D Co., Ltd.). In this measurement, the measurement temperature was 25°C, the peel angle was 90°, and the peel speed was 1000 mm / min. The results of each example and comparative example are shown in Table 1. The pass criterion for peel strength was 1.0 (N / 15 mm) or more, and 1.2 (N / 15 mm) or more is preferable.

[0079] <Method for calculating HSP of adhesive composition> The HSP of the active energy ray-curable adhesive composition was determined by calculating the Hansen solubility parameter (HSP) for each of the constituent materials of the composition using the Y-MB method of Hansen Solubility Parameter in Practice (HSPiP) and then averaging the values ​​according to the molar ratio in the composition.

[0080] <Method for Calculating HSP of Optical Film with UV Absorption Capability> An optical film with UV absorption capability was immersed for 24 hours in nine solvents with different solubilities: acetone, ethyl acetate, trichlorobenzene, propylene carbonate, γ-butyrolactone, methyl ethyl ketone, diacetone alcohol, hexane, methanol, and a mixture thereof. The state of the transparent protective film after 24 hours of immersion was classified into three stages: (1) dissolved, (2) swollen, and (3) insoluble. Based on the solubility information in each solvent obtained in this way, the Hansen Solubility Parameter (HSP) was calculated using Hansen Solubility Parameter in Practice (HSPiP) version 5.4.04 (http: / / www.hansen-solubility.com / index.php).

[0081] <Method of Calculating HSP Distance> When the dispersion term of the Hansen solubility parameters of the optical film having ultraviolet absorption ability is σd, the polar term is σp, and the hydrogen bond term is σh, and the dispersion term of the Hansen solubility parameters of the active energy ray-curable adhesive composition is σAd, the polar term is σAp, and the hydrogen bond term is σAh, the HSP distance can be calculated using the following formula: Ra-1=[4×(σd-σAd)] ２ +2×(σp−σAp) ２ +2×(σh−σAh) ２ ] １／２ was defined as the "HSP distance between the HSP of the optical film having ultraviolet absorbing ability and the HSP of the adhesive composition" (= Ra-1). Calculation was performed using the Hansen solubility parameters of the optical film having ultraviolet absorbing ability and the active energy ray-curable adhesive composition calculated by the above-mentioned method. The values ​​for each example and comparative example are shown in Table 1.

[0082]

Claims

1. An active energy ray-curable adhesive composition for an optical film, characterized by containing vinyl methyl oxazolidinone.

2. The active energy ray-curable adhesive composition for an optical film according to claim 1, characterized by containing a (meth)acrylamide derivative containing a cyclic ether group.

3. The active energy ray-curable adhesive composition for an optical film according to claim 2, characterized in that the mass ratio of the (meth)acrylamide derivative containing a cyclic ether group to vinyl methyl oxazolidinone ((meth)acrylamide derivative containing a cyclic ether group / vinyl methyl oxazolidinone) is 2 or more and 10 or less.

4. An optical film 1, an adhesive layer formed from the active energy ray-curable adhesive composition for an optical film according to any one of claims 1 to 3, and an optical film 2 are laminated in this order, and at least one of the optical films 1 and 2 is an optical film having ultraviolet absorption ability. A laminated optical film characterized by this.

5. The laminated optical film according to claim 4, characterized in that the optical film having ultraviolet absorption ability has a transmittance of 10% or less with respect to light of 380 nm.

6. The laminated optical film according to claim 4, characterized in that the optical film 1 is an optical film having ultraviolet absorption ability, and the optical film 2 is a polarizer.

7. The optical film having the ultraviolet absorption ability is a polycarbonate resin, and the polycarbonate resin has the formula (1): The laminated optical film according to claim 4, characterized by containing a structural unit derived from a dihydroxy compound represented by

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