Laminated optical film

Abstract

An optical film 1, an adhesive layer, and an optical film 2 are laminated in this order to form a laminated optical film. At least one of the optical films 1 and 2 is a polycarbonate-based resin film. The polycarbonate-based resin film contains structural units derived from a dihydroxy compound represented by formula (1). The HSP distance between the HSP of the polycarbonate-based resin film and the HSP of an adhesive composition forming the adhesive layer is 4.0 or less. The laminated optical film has excellent adhesiveness with regard to a polycarbonate-based resin containing structural units derived from isosorbide.

Description

Laminated Optical Film

[0001] The present invention relates to 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 the optical film described above, Patent Document 1 discloses the use of a polycarbonate resin containing a structural unit derived from isosorbide, from the viewpoint of excellent moist heat resistance, dimensional stability, and mechanical strength. Patent Document 2 specifically discloses an optical laminate using a retardation layer composed of the above polycarbonate resin film and bonded with an active energy ray-curable adhesive composition.

[0004] JP 2016-90921 A JP 2021-173831 A

[0005] However, when an optical film made of a polycarbonate resin containing a structural unit derived from isosorbide is used in the optical laminate as described above, there is room for improvement in the adhesiveness between the film and the active energy ray-curable adhesive composition.

[0006] In view of the above circumstances, an object of the present invention is to provide a laminated optical film having excellent adhesiveness, which is made of a polycarbonate resin containing a structural unit derived from isosorbide.

[0007] That is, the present invention provides a laminated optical film in which an optical film 1, an adhesive layer, and an optical film 2 are laminated in this order, and at least one of the optical films 1 and 2 is a polycarbonate-based resin film, and the polycarbonate-based resin film is represented by formula (1): and the HSP distance between the HSP of the polycarbonate-based resin film and the HSP of the adhesive composition forming the adhesive layer is 4.0 or less.

[0008] Furthermore, in the laminated optical film of the present invention, it is preferable that the adhesive composition contains radical polymerizable compounds including a monofunctional radical polymerizable compound and a bifunctional or higher polyfunctional radical polymerizable compound, and that the proportion of the monofunctional radical polymerizable compound in the radical polymerizable compounds is 65 mass% or more and the proportion of the bifunctional or higher polyfunctional radical polymerizable compound is 35 mass% or less.

[0009] In the laminated optical film of the present invention, the monofunctional radically polymerizable compound is preferably a cyclic ether group-containing (meth)acrylamide derivative.

[0010] In the laminated optical film of the present invention, the bifunctional or higher polyfunctional radical polymerizable compound is preferably a bifunctional radical polymerizable compound having an alicyclic structure.

[0011] The laminated optical film of the present invention has excellent adhesiveness because the HSP distance between the HSP of the optical film made of a polycarbonate-based resin containing structural units derived from isosorbide (including its optical isomers) and the HSP of the adhesive composition is a specific value or less, and it is presumed that components derived from the polycarbonate-based resin can penetrate into the adhesive layer.

[0012] The laminated optical film of the present invention comprises an optical film 1, an adhesive layer, and an optical film 2 laminated in this order, and at least one of the optical films 1 and 2 is a polycarbonate-based resin film.

[0013] <Polycarbonate-Based Resin Film> The polycarbonate-based resin film is a polycarbonate-based resin film represented by formula (1): The dihydroxy compound contains a structural unit derived from a dihydroxy compound represented by the formula:

[0033] 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.

[0014] 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.

[0015] Examples of other dihydroxy compounds include alicyclic dihydroxy compounds, aliphatic dihydroxy compounds, oxyalkylene glycols, aromatic dihydroxy compounds, and diols having a cyclic ether structure.

[0016] 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.

[0017] 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.

[0018] 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.

[0019] 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.

[0020] In the laminated optical film, the HSP distance between the HSP of the polycarbonate-based resin film and the HSP of the adhesive composition forming the adhesive layer is 4.0 or less. From the viewpoint of adhesiveness, the HSP distance (Ra-1 described below) between the HSP of the polycarbonate-based resin film and the HSP of the adhesive composition forming the adhesive layer is preferably 0.5 or more, more preferably 1 or more, and from the viewpoint of adhesiveness, is preferably 10 or less, more preferably 5 or less. Note that methods for measuring the HSP of the polycarbonate-based resin film and adhesive composition will be described later.

[0021] <Adhesive Composition> The adhesive composition can be broadly classified into electron beam curable, ultraviolet curable, and visible light curable adhesive compositions. Furthermore, the type of curing 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.

[0022] <Radical Polymerizable Compound> The radical polymerizable compound used in the adhesive composition includes a compound 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 are 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.

[0023] <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 ３are 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.

[0024] 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.

[0025] In addition to the above compounds, the adhesive composition may contain other monofunctional radically polymerizable compounds as curable components, from the viewpoint of enabling the adhesive composition to exhibit various functions. Examples of other monofunctional radically 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] From the viewpoint of achieving both adhesiveness to the optical film and optical durability under harsh environments, it is preferable to use a monofunctional radically polymerizable compound and a polyfunctional radically polymerizable compound in combination as the radically polymerizable compound. Since the monofunctional radically polymerizable compound has a relatively low liquid viscosity, the liquid viscosity of the adhesive composition can be reduced by including it in 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.

[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, ne Examples of the ester include esters of (meth)acrylic acid and polyhydric alcohols such as pentyl glycol di(meth)acrylate, dimethyloltricyclodecane 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] When the monofunctional radical polymerizable compound and the polyfunctional radical polymerizable compound are used in combination, the proportion of the monofunctional radical polymerizable compound in the radical polymerizable compounds is preferably 65% ​​by mass or more, more preferably 70% by mass or more, and even more preferably 75% by mass or more, and from the viewpoint of adhesive strength, is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less. In this case, the proportion of the polyfunctional radical polymerizable compound in the radical polymerizable compounds is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and preferably 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less, from the viewpoint of adhesive strength.

[0034] Furthermore, when a compound represented by the above formula (2) is used as the monofunctional radically polymerizable compound, the proportion of the above formula (2) in the radically polymerizable compound is preferably 65% ​​by mass or more, more preferably 70% by mass or more, and even more preferably 75% by mass or more, and is preferably 95% by mass or less, more preferably 90% by mass or more, and even more preferably 85% by mass or less.

[0035] When the other monofunctional radical polymerizable compound is used as the monofunctional radical polymerizable compound, the proportion of the other monofunctional radical polymerizable compound in the radical polymerizable compound is usually about 30 mass % or less.

[0036] When ultraviolet light or visible light is used as the active energy ray, the adhesive composition preferably contains a photopolymerization initiator.

[0037] <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.

[0038] Furthermore, when the optical film 1 or 2 used for bonding the adhesive composition has poor transmittance of 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.

[0039] 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.

[0040] 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.).

[0041] 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.

[0042] 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.

[0043] 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).

[0044] The adhesive composition may contain various additives as other optional components within the scope of the present invention, provided that the additives do 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.

[0045] <Laminated Optical Film> The laminated optical film of the present invention comprises an optical film 1, an adhesive layer formed from the adhesive composition, and an optical film 2 laminated in this order, and at least one of the optical films 1 and 2 is the polycarbonate-based resin film. 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."

[0046] The optical film may be an optical film having ultraviolet absorption ability, from the viewpoint of being able to protect polarizers, liquid crystals, etc. from ultraviolet rays when the laminated optical film is incorporated into various image display devices. In this case, the transmittance for light of 380 nm is preferably 20% or less, more preferably 10% or less. To impart ultraviolet absorption ability to the optical film, for example, the material constituting the optical film may have ultraviolet absorption 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.

[0047] 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).

[0048] The optical film 1 or 2 that is not a polycarbonate-based resin film is not particularly limited, and may be, for example, any of various transparent protective films used in various image display devices. 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, isotropy, etc. 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 may have a cured layer formed from a thermosetting resin or an 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 preferred. The transparent protective film may contain any suitable additives, such as an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, a color inhibitor, a flame retardant, an antistatic agent, a pigment, or a colorant.

[0049] The thickness of the optical 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.

[0050] When the laminated optical film is used as a polarizing film, it is preferable that the optical film 1 is the polycarbonate-based resin film 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] In the laminated optical film, the adhesive composition is applied directly to optical film 1 and / or optical film 2, and after the optical film 1 and the optical film 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 adhesive composition 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. Note that in a polarized film (in an embodiment in which optical film 1 is the polycarbonate-based resin film and optical film 2 is a polarizer), irradiating the adhesive composition from the polarizer side may cause deterioration of the polarizer due to active energy rays. Therefore, the adhesive composition is useful because it can be irradiated from the optical film side having ultraviolet absorption ability.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] Examples of the surface modification treatment for forming the surface modification layer include corona treatment, plasma treatment, primer treatment, and saponification treatment.

[0060] Examples of the 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] The laminated optical film can be used in various image display devices such as liquid crystal display devices and organic EL display devices.

[0067] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

[0068] Examples 1 to 6, Comparative Example 1 Preparation of Adhesive Composition In each of the Examples and Comparative Examples, 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 the amounts shown in Table 1 are relative parts by mass). ACMO: N-acryloylmorpholine, manufactured by KJ Chemicals. DCP-A: "Light Acrylate DCP-A", dimethyloltricyclodecane diacrylate, manufactured by Kyoeisha Chemical Co., Ltd. DPHA: dipentaerythritol hexaacrylate, manufactured by Tokyo Chemical Industry Co., Ltd. M220: "Aronix M220", tripropylene glycol diacrylate, manufactured by Toagosei Co., Ltd. 9EGA: "Light Acrylate 9EG-A", PEG#400 diacrylate, manufactured by Kyoeisha Chemical Co., Ltd. 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.

[0069] <Preparation of Polycarbonate-Based Resin Film> 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, and 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 withdrawn 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 withdrawn 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.

[0070] <Preparation of Laminated Optical Film> The adhesive composition was applied to two optical films composed of the polycarbonate resin obtained above so that the total film thickness after curing was 1.0 μm. For the 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 films obtained above were bonded together via the adhesive-coated surfaces. Next, the obtained laminate was irradiated with ultraviolet light to cure the adhesive composition between the films, thereby obtaining a laminated optical film. A gallium lamp was used for ultraviolet irradiation, 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

[0071] <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 parallel to the conveying direction during optical film formation. The second side was the side extending perpendicular to the conveying direction. Next, the optical film on the UV-irradiated surface of the sample film was bonded 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, with 1.5 (N / 15 mm) or more being preferred.

[0072] <Method for calculating HSP of adhesive composition> The HSP of the 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.

[0073] <Method for Calculating HSP of Polycarbonate-Based Resin Film> Polycarbonate-based resin films were 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).

[0074] <Method of Calculating HSP Distance> When the dispersion term of the Hansen solubility parameter of the polycarbonate resin film is σd, the polar term is σp, and the hydrogen bond term is σh, and the dispersion term of the Hansen solubility parameter of the adhesive composition is σAd, the polar term is σAp, and the hydrogen bond term is σAh, the HSP distance can be calculated by 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 polycarbonate-based resin film and the HSP of the adhesive composition" (= Ra-1). Calculations were made using the Hansen solubility parameters of the polycarbonate-based resin film and adhesive composition calculated by the method described above. The values ​​for each example and comparative example are shown in Table 1.

[0075]

Claims

1. A laminated optical film in which an optical film 1, an adhesive layer, and an optical film 2 are laminated in this order, at least one of the optical films 1 and 2 is a polycarbonate resin film, and the polycarbonate resin film has the formula (1): contains a structural unit derived from a dihydroxy compound represented by, and the HSP distance between the HSP of the polycarbonate resin film and the HSP of the adhesive composition forming the adhesive layer is 4.0 or less. A laminated optical film characterized by this.

2. The adhesive composition contains a monofunctional radically polymerizable compound and a radically polymerizable compound containing a polyfunctional radically polymerizable compound having two or more functional groups. In the radically polymerizable compound, the proportion of the monofunctional radically polymerizable compound is 65% by mass or more, and the proportion of the polyfunctional radically polymerizable compound having two or more functional groups is 35% by mass or less. The laminated optical film according to claim 1, characterized in that.

3. The laminated optical film according to claim 2, characterized in that the monofunctional radically polymerizable compound is a (meth)acrylamide derivative containing a cyclic ether group.

4. The laminated optical film according to claim 2 or 3, characterized in that the polyfunctional radically polymerizable compound having two or more functional groups is a bifunctional radically polymerizable compound having an alicyclic structure.

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