Optical film, polarizing plate, and organic electroluminescence image display device

Abstract

The present invention addresses the problem of providing: an optical film that, when applied to an image display device, prevents light leakage despite having high transparency, and also has excellent light resistance and durability under harsh environmental conditions; and a polarizing plate and organic electroluminescence image display device that are provided with the optical film.　The optical film according to the present invention contains a thermoplastic resin, and is characterized by containing a compound having a structure represented by general formula (1). (In the formula, Z represents a heteroaryl group having two or more heteroatoms, and is optionally substituted.)

Description

[Technical field]

[0001] The present invention relates to an optical film, a polarizing plate, and an organic electroluminescence image display device, and more particularly to an optical film and the like that, when applied to an image display device, has high transparency while preventing light leakage and is excellent in light resistance and durability under severe environmental conditions. [Background technology]

[0002] In organic electroluminescence (hereinafter also referred to as "organic EL") image display devices, the reflection of external light from the metal plate inside is significant, so an anti-reflection film combining a λ / 4 retardation film and a polarizer is used. When a cyclic olefin resin (hereinafter also referred to as "COP") is used as the material for the retardation film, the wavelength dispersion of the resin causes reflection leakage of specific wavelengths. Therefore, in order to suppress reflection leakage, it is necessary to incorporate a layer containing a dye that absorbs light of a specific wavelength (hereinafter also referred to as a "specific wavelength light absorbing layer") into the display. The specific wavelength light absorbing layer may be provided anywhere within the display, and may be provided as the λ / 4 retardation film.

[0003] However, when a retardation film is produced by directly adding a dye to a resin, the dye interacts with the resin, which may accelerate photodegradation of the dye.

[0004] For example, Patent Document 1 discloses a method of adding a dye that absorbs light with a wavelength of around 400 nm to an adhesive layer in order to protect an organic EL element, and Patent Document 2 discloses a method of adding a dye that selectively absorbs light with wavelengths of around 470 nm and 600 nm to an adhesive in order to improve the brightness and visibility of an organic EL image display device.

[0005] These techniques mainly involve adding dyes or UV absorbers to the adhesive, but because the adhesive layer is thin, it is difficult to uniformly add the compounds required to achieve the desired functionality.

[0006] Patent Document 3 describes that a plurality of dye compounds may be added to any layer of the functional layer in order to block ultraviolet light and some visible light from the outside. Patent Document 4 describes the inclusion of an indole compound in a thickener or the like, and Patent Document 5 describes the addition of a dye compound of a specific structure having a cyano group and an ester group to a resin or a functional layer, but all of these dye compounds have the problem of insufficient light resistance. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2017-165941 A [Patent Document 2] Patent No. 5599740 [Patent Document 3] JP 2017-198991 A [Patent Document 4] International Publication No. 2017 / 15996 [Patent Document 5] JP 2018-200463 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of the above problems and circumstances, and the problem to be solved is to provide an optical film which, when applied to an image display device, has high transparency while preventing light leakage and has excellent light resistance and durability under severe environmental conditions, and a polarizing plate and an organic electroluminescent image display device each equipped with the optical film. [Means for solving the problem]

[0009] Means for Solving the Problems The present inventors, in the course of investigating the causes of the above problems in order to solve the above problems, have found that an optical film containing a thermoplastic resin, which contains a compound having a specific structure, can be obtained that, when applied to an image display device, has high transparency while preventing light leakage, and further has excellent light resistance and durability even under severe environmental conditions.

[0010] That is, the above-mentioned problems of the present invention are solved by the following means.

[0011] 1. An optical film containing a thermoplastic resin, An optical film comprising a compound having a structure represented by the following general formula (1):

[0012] [ka]

[0013] (Wherein, Z is Any of the groups represented by the following structural formulas .)

[0015] [ka]

[0016] ( The * symbol indicates the bonding position with the carbon atom of the double bond. The group represented by the above structural formula may further have a substituent. R represents a substituent.

[0017] 2 Furthermore, the present invention is characterized in that Z is any one of the groups represented by the following structural formulas: 1 Item 1. The optical film according to item 1.

[0018] [ka]

[0019] ( The * symbol indicates the bonding position with the carbon atom of the double bond. The group represented by the above structural formula may further have a substituent. R represents a substituent.

[0020] 3 The energy level of the highest occupied molecular orbital of the compound having the structure represented by the general formula (1) is -7.45ev or higher, Item 1, characterized in that the potential is −5.85 eV or less or No. In item 2 The optical film described herein.

[0021] 4 The thermoplastic resin is a cyclic olefin resin or an acrylic resin. 3 Item 1. The optical film according to any one of items 1 to 5.

[0022] 5 The cyclic olefin resin has a polar group. 4 Item 1. The optical film according to item 1.

[0023] 6 The compound having the structure represented by the general formula (1) is contained in the thermoplastic resin in an amount of 0.01 to 20% by mass. 5 Item 1. The optical film according to any one of items 1 to 5.

[0024] 7 Further, the present invention is characterized in that the film has a functional layer. 6 Item 1. The optical film according to any one of items 1 to 5.

[0025] 8 The functional layer contains a compound having a structure represented by the general formula (1). 7 Item 1. The optical film according to item 1.

[0026] 9 The optical film is a λ / 4 retardation film. 8 Item 1. The optical film according to any one of items 1 to 5.

[0027] 10 .Items 1 to 5 93. A polarizing plate comprising the optical film according to claim 1.

[0028] 11 .Items 1 to 5 9 The optical film according to any one of claims 1 to 4 or 10 2. An organic electroluminescence image display comprising the polarizing plate according to claim 1. Effect of the Invention

[0029] According to the above-mentioned means of the present invention, it is possible to provide an optical film which, when applied to an image display device, has high transparency while preventing light leakage and has excellent light resistance and durability even under severe environmental conditions, and a polarizing plate and an organic electroluminescence image display device equipped with the same.

[0030] Although the mechanism by which the effects of the present invention are expressed or the mechanism of action has not been clarified, it is speculated as follows.

[0031] As the λ / 4 retardation film, a cyclic olefin resin film is sometimes used from the viewpoints of low moisture absorption and good dimensional stability.

[0032] However, since the cyclic olefin resin film exhibits flat wavelength dispersion characteristics, when it is used as a λ / 4 retardation film for a circular polarizer in an organic electroluminescence (hereinafter also referred to as "organic EL") image display device, reflected light is likely to leak in a specific wavelength region (region on the short wavelength side). If such leakage of reflected light is significant, the color of the reflected light is likely to deteriorate.

[0033] In order to suppress the deterioration of color tone due to the reflected light, the present inventors have considered adding a dye compound that absorbs light in the relevant wavelength range to the film. Since organic EL image display devices are used in high temperature and high humidity environments, it is necessary to suppress the deterioration of the organic EL element due to external light. In addition, since the dye compound also deteriorates due to incident light, the compound itself is also required to have light resistance.

[0034] Therefore, in order to solve these problems, we thought that by using a dye compound with a specific structure, it would be possible to suppress photodegradation, and further, by combining it with a specific thermoplastic resin, it would be possible to produce a λ / 4 retardation film with improved durability overall.

[0035] As a result of the investigation, it was found that when the dye compound of the specific structure has a structure having a dicyano group, the cyano group can lower the energy level of the highest occupied molecular orbital (HOMO), i.e., can lower the oxidation potential, thereby suppressing photooxidation and thus improving the light resistance of the dye compound. It was also found that by selecting a resin type in which the energy level of the highest occupied molecular orbital (HOMO) of the dye compound and the corresponding energy level of the thermoplastic resin are unlikely to interact with each other, the deterioration of light resistance and durability can be further suppressed. [Brief description of the drawings]

[0036] [Figure 1] A cross-sectional view showing the configuration of a polarizing plate 100. [Diagram 2] An exploded cross-sectional view of an organic EL image display device 200. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0037] The optical film of the present invention is an optical film containing a thermoplastic resin, and is characterized in that it contains a compound having a structure represented by the general formula (1). This feature is a technical feature common to or corresponding to the following embodiments.

[0038] As an embodiment of the present invention, from the viewpoint of exerting the effects of the present invention, Z in the structure represented by the general formula (1) is The above structural formula From the viewpoint of obtaining an optical film having an excellent balance between prevention of light leakage and light resistance, it is preferable that the group be any of the groups having the structure represented by the following formula:

[0039] In addition, it is preferable that the highest occupied molecular orbital energy level of the compound having the structure represented by the general formula (1) is −5.85 eV or less, from the viewpoint of obtaining an optical film having excellent durability.

[0040] Furthermore, it is preferable that the thermoplastic resin is a cyclic olefin resin or an acrylic resin, from the viewpoint of preventing light leakage and obtaining an optical film excellent in light resistance and durability. In particular, when the cyclic olefin resin has a polar group, the energy level of the highest occupied molecular orbital of the dye and the corresponding energy level of the resin are less likely to interact with each other, and deterioration of light resistance and durability can be suppressed.

[0041] In the present invention, the compound having the structure represented by the general formula (1) is preferably contained in the range of 0.01 to 20% by mass relative to the thermoplastic resin. If it is less than 0.01% by mass, the effect of the present invention is small, and if it exceeds 20% by mass, precipitation (also called bleed-out) from the film is likely to occur under high temperature and high humidity conditions.

[0042] Furthermore, the optical film preferably has a functional layer, and the functional layer preferably contains a compound having a structure represented by the general formula (1). Examples of the functional layer include a hard coat layer, an adhesive layer, a smooth layer, and a light scattering layer, and the like. From the viewpoint of imparting scratch resistance to the optical film, the hard coat layer is preferable.

[0043] The optical film of the present invention is preferably a λ / 4 retardation film, and by incorporating it in a polarizing plate, it is possible to provide an anti-reflection circular polarizing plate.

[0044] The organic electroluminescent image display device of the present invention is characterized by comprising the optical film or polarizing plate of the present invention.

[0045] The present invention, its components, and embodiments for carrying out the present invention will be described in detail below. In this application, the symbol "to" is used to mean that the numerical values ​​before and after the symbol "to" are included as the lower limit and upper limit.

[0046] <Outline of the optical film of the present invention> The optical film of the present invention is an optical film containing a thermoplastic resin, and is characterized in that it contains a compound having a structure represented by the following general formula (1).

[0047] According to the present invention, by using a compound having a structure represented by general formula (1), the energy level of the highest occupied molecular orbital (HOMO) can be lowered. By lowering the energy level of the HOMO, the oxidation potential can be lowered and photooxidation can be suppressed. In other words, there is an effect of improving the light resistance of the dye compound.

[0048] The HOMO of the compound having the structure represented by the general formula (1) can be calculated by molecular orbital calculation software using B3LYP as a functional and 6-31G(d) as a basis function as a calculation method. There is no particular limitation on the software, and any software can be used to obtain the HOMO in the same manner.

[0049] In the present invention, Gaussian09 (Revision C.01, MJ Frisch, et al., Gaussian, Inc., 2010.), manufactured by Gaussian, Inc., USA, is used as the molecular orbital calculation software.

[0050] In addition, the optical film of the present invention is preferably transparent, and "transparent" means that the light transmittance is 80% or more when measured using a spectrophotometer (e.g., U-3300 manufactured by Hitachi High-Tech Science) in accordance with JIS K 7375:2008 "Plastics - Determination of total light transmittance and total light reflectance".

[0051] The components of the present invention will now be described in detail.

[0052] [1] A compound having a structure represented by general formula (1) The compound having a structure represented by general formula (1) according to the present invention (hereinafter also referred to as a "dye compound") has the following structure.

[0053] [ka]

[0054] (In the formula, Z represents a heteroaryl group having two or more heteroatoms and may have a substituent.)

[0055] Furthermore, in the formula, Z is any group represented by the following structural formula, which may further have a substituent: In the following structural formula, R represents a substituent. The * symbol indicates the bonding position with the carbon atom of the double bond.

[0056] [ka]

[0057] Among these, from the viewpoint of exerting the effects of the present invention, it is more preferable that Z is any of the groups represented by the following structural formulas: In the following structural formulas, R represents a substituent.

[0058] [ka]

[0059] The R represents a substituent, for example, a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.), an alkyl group (a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a tert-butyl group, a n-octyl group, a 2-ethylhexyl group, etc.), a cycloalkyl group (a cyclohexyl group, a cyclopentyl group, a 4-n-dodecylcyclohexyl group, etc.), an alkenyl group (a vinyl group, an allyl group, etc.), a cycloalkenyl group (a 2-cyclopenten-1-yl group, a 2-cyclohexen-1-yl group, etc.), an alkynyl group (an ethynyl group, a propargyl group, etc.), Aromatic hydrocarbon ring groups (phenyl group, p-tolyl group, naphthyl group, etc.), aromatic heterocyclic groups (2-pyrrole group, 2-furyl group, 2-thienyl group, pyrrole group, imidazolyl group, oxazolyl group, thiazolyl group, benzimidazolyl group, benzoxazolyl group, 2-benzothiazolyl group, pyrazolinone group, pyridyl group, pyridinone group, 2-pyrimidinyl group, triazine group, pyrazole group, 1,2,3-triazole group, 1,2,4-triazole group, oxazole group, isoxazole group, 1,2,4-oxadiazole group, 1,3,4-oxazole group, sadiazole group, thiazole group, isothiazole group, 1,2,4-thiodiazole group, 1,3,4-thiadiazole group, etc.), cyano group, hydroxy group, nitro group, carboxy group, alkoxy group (methoxy group, ethoxy group, isopropoxy group, tert-butoxy group, n-octyloxy group, 2-methoxyethoxy group, etc.), aryloxy group (phenoxy group, 2-methylphenoxy group, 4-tert-butylphenoxy group, 3-nitrophenoxy group, 2-tetradecanoylaminophenoxy group, etc.), acyloxy group (formyloxy group, acetyloxy group, pivaloyloxy group, stearoyloxy group, benzoyloxy group, p-methoxyphenylcarbonyloxy group, etc.), amino group (amino group, methylamino group, dimethylamino group, anilino group, N-methyl-anilino group, diphenylamino group, etc.), acylamino group (formylamino group, acetylamino group, pivaloylamino group, lauroylamino group, benzoylamino group, etc.), alkyl and arylsulfonylamino group (methylsulfonylamino group, butylsulfonylamino group, phenylsulfonylamino group, 2,3,5-trichlorophenylsulfonylamino group, p-methylphenylsulfonylamino group, etc.), mercapto group, alkylthio group (methylthio group, ethylthio group, n-hexadecylthio group, etc.), arylthio group (phenylthio group, p-chlorophenylthio group, m-methoxyphenylthio group, etc.), sulfamoyl group (N-ethylsulfamoyl group, N-(3-dodecyloxypropyl)sulfamoyl group, N,N-dimethylsulfamoyl group, N-acetylsulfamoyl group, N-benzoylsulfamoyl group, N-(N'-phenylcarbamoyl)sulfamoyl group, etc.), sulfo group, acyl group (acetyl group, pivaloylbenzoyl group, etc.), carbamoyl group (carbamoyl group, N-methylcarbamoyl group, N,N-dimethylcarbamoyl group, N,N-di-n-octylcarbamoyl group, N-(methylsulfonyl)carbamoyl group, etc.). ,

[0060] Examples of dye compounds having a structure represented by general formula (1) according to the present invention are given below, but the present invention is not limited thereto.

[0061] [ka]

[0062] [ka]

[0063] [ka]

[0064] [ka]

[0065] The molecular weight of the dye compound is not particularly limited, but in order to facilitate incorporation between molecules of the cyclic olefin resin or acrylic resin, it is preferable that the molecular weight is not too large, for example, 100 to 1000. The molecular weight of the dye compound can be calculated from the formula weight of the chemical structure by identifying the chemical structure using, for example, an NMR (Nuclear Magnetic Resonance) device.

[0066] The maximum absorption wavelength of the dye compound is preferably in the range of 370 to 460 nm, more preferably in the range of 400 to 440 nm. When the maximum absorption wavelength of the dye compound is within the above range, the optical film is likely to adequately absorb light in the wavelength region, so that, for example, when the optical film is used as a λ / 4 retardation film in an organic EL image display device, leakage of reflected light in the wavelength region can be further suppressed. The maximum absorption wavelength of the dye compound can be determined by measuring the absorption spectrum of the dye compound in dichloromethane using a UV-2450 ultraviolet-visible spectrophotometer manufactured by Shimadzu Corporation.

[0067] The dye compound may be synthesized or may be a commercially available product. For example, the exemplary dye compound 12 may be synthesized according to the following scheme.

[0068] [ka]

[0069] 1.5 g of compound (12-1) and 0.697 g of malononitrile were weighed into a 100 mL three-head flask, and 40 mL of toluene was added to dissolve. Next, 0.817 g of morpholine was added dropwise, and the mixture was heated and refluxed for 4 hours. After the reaction was completed, the solvent was removed under reduced pressure, and 10 mL of methanol was added and stirred in a suspended state. The precipitate was filtered and dried to obtain 1.89 g (yield 96%) of powder of exemplary dye compound 12. The structure was confirmed by NMR.

[0070] The content of the dye compound is preferably in the range of 0.01 to 20% by mass relative to the cyclic olefin resin. When the content of the dye compound is 0.01% by mass or more, the light in a specific wavelength region is appropriately absorbed, and the effect of improving light resistance while suppressing leakage of reflected light in, for example, an organic EL image display device is obtained. When the content of the dye compound is 20% by mass or less, not only can bleed-out be made less likely to occur, but also a decrease in brightness can be suppressed since the absorption of light in a specific wavelength region of the optical film is not too high. From the same viewpoint, the content of the dye compound is more preferably in the range of 0.015 to 10% by mass relative to the cyclic olefin resin.

[0071] [2] Thermoplastic resin The thermoplastic resin material according to the present invention is not limited as long as it can be handled as a film after film formation. For example, thermoplastic resins used for polarizing plates include cellulose ester resins such as triacetyl cellulose (TAC), cellulose acetate propionate (CAP), and diacetyl cellulose (DAC), cyclic olefin resins such as cycloolefin polymers (hereinafter also referred to as COP or cycloolefin resins), polypropylene resins such as polypropylene (PP), acrylic resins such as polymethyl methacrylate (PMMA), and polyester resins such as polyethylene terephthalate (PET).

[0072] Among these, from the viewpoints of optical properties including retardation and physical properties such as durability, cyclic olefin resins and acrylic resins are preferred.

[0073] [2.1] Cycloolefin resin The cycloolefin resin contained in the optical film of the present invention is preferably a polymer of a cycloolefin monomer, or a copolymer of a cycloolefin monomer and another copolymerizable monomer.

[0074] The cycloolefin monomer is preferably a cycloolefin monomer having a norbornene skeleton, and more preferably a cycloolefin monomer having a structure represented by the following general formula (A-1) or (A-2).

[0075] [ka]

[0076] In general formula (A-1), R 1 ~R 4 each independently represents a hydrogen atom, a hydrocarbon group having 1 to 30 carbon atoms, or a polar group, and p represents an integer of 0 to 2. 1 ~R 4 Not all of these represent hydrogen atoms at the same time, and R 1 and R 2 does not simultaneously represent a hydrogen atom, and R 3 and R 4 does not simultaneously represent a hydrogen atom.

[0077] In general formula (A-1), R 1 ~R 4 The hydrocarbon group having 1 to 30 carbon atoms represented by the formula (I) is preferably a hydrocarbon group having 1 to 10 carbon atoms, more preferably a hydrocarbon group having 1 to 5 carbon atoms. The hydrocarbon group having 1 to 30 carbon atoms may further have a linking group containing, for example, a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom, or a silicon atom. Examples of such linking groups include divalent polar groups such as a carbonyl group, an imino group, an ether bond, a silyl ether bond, and a thioether bond. Examples of the hydrocarbon group having 1 to 30 carbon atoms include a methyl group, an ethyl group, a propyl group, and a butyl group.

[0078] In general formula (A-1), R 1 ~R 4Examples of the polar group represented by the formula (I) include a carboxy group, a hydroxy group, an alkoxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an amino group, an amide group, and a cyano group. Among them, a carboxy group, a hydroxy group, an alkoxycarbonyl group, and an aryloxycarbonyl group are preferred, and an alkoxycarbonyl group and an aryloxycarbonyl group are preferred from the viewpoint of ensuring solubility during solution casting.

[0079] In terms of improving the heat resistance of the optical film, p in general formula (A-1) is preferably 1 or 2. When p is 1 or 2, the obtained polymer becomes bulky and the glass transition temperature is likely to be improved.

[0080] [ka]

[0081] In general formula (A-2), R 5 R represents a hydrogen atom, a hydrocarbon group having 1 to 5 carbon atoms, or an alkylsilyl group having an alkyl group having 1 to 5 carbon atoms. 6 represents a carboxy group, a hydroxy group, an alkoxycarbonyl group, an aryloxycarbonyl group, an amino group, an amido group, a cyano group, or a halogen atom (a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom). p represents an integer of 0 to 2.

[0082] R in general formula (A-2) 5 preferably represents a hydrocarbon group having 1 to 5 carbon atoms, and more preferably represents a hydrocarbon group having 1 to 3 carbon atoms.

[0083] R in general formula (A-2) 6 preferably represents a carboxy group, a hydroxy group, an alkoxycarbonyl group or an aryloxycarbonyl group, and more preferably an alkoxycarbonyl group or an aryloxycarbonyl group from the viewpoint of ensuring solubility during solution casting.

[0084] In terms of improving the heat resistance of the optical film, p in general formula (A-2) preferably represents 1 or 2. When p represents 1 or 2, the obtained polymer becomes bulky and the glass transition temperature is likely to be improved.

[0085] Cycloolefin monomers having a structure represented by general formula (A-2) are preferred from the viewpoint of improving solubility in organic solvents. In general, by breaking the symmetry of an organic compound, the crystallinity is reduced, and the solubility in organic solvents is improved. R in general formula (A-2) 5 and R 6 is substituted only on the ring carbon atom on one side of the axis of symmetry of the molecule, so that the molecular symmetry is low. In other words, a cycloolefin monomer having a structure represented by general formula (A-2) has high solubility and is therefore suitable for producing an optical film by a solution casting method.

[0086] The content ratio of the cycloolefin monomer having the structure represented by general formula (A-2) in the polymer of the cycloolefin monomer can be, for example, 70 mol% or more, preferably 80 mol% or more, more preferably 100 mol% based on the total of all the cycloolefin monomers constituting the cycloolefin resin. If the cycloolefin monomer having the structure represented by general formula (A-2) is contained at a certain level or more, the orientation of the resin is increased, so that the retardation value is likely to increase.

[0087] Specific examples of cycloolefin monomers having a structure represented by general formula (A-1) are shown in Exemplary Compounds 1 to 14 below, and specific examples of cycloolefin monomers having a structure represented by general formula (A-2) are shown in Exemplary Compounds 15 to 34 below.

[0088] [ka]

[0089] Examples of the copolymerizable monomer copolymerizable with the cycloolefin monomer include a copolymerizable monomer capable of ring-opening copolymerization with the cycloolefin monomer, and a copolymerizable monomer capable of addition copolymerization with the cycloolefin monomer.

[0090] Examples of copolymerizable monomers capable of ring-opening copolymerization include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene.

[0091] Examples of copolymerizable monomers capable of addition copolymerization include unsaturated double bond-containing compounds, vinyl cyclic hydrocarbon monomers, and (meth)acrylates. Examples of unsaturated double bond-containing compounds include olefin compounds having 2 to 12 carbon atoms (preferably 2 to 8), examples of which include ethylene, propylene, and butene. Examples of vinyl cyclic hydrocarbon monomers include vinylcyclopentene monomers such as 4-vinylcyclopentene and 2-methyl-4-isopropenylcyclopentene. Examples of (meth)acrylates include alkyl (meth)acrylates having 1 to 20 carbon atoms, such as methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, and cyclohexyl (meth)acrylate.

[0092] The content of the cycloolefin monomer in the copolymer of a cycloolefin monomer and a copolymerizable monomer can be, for example, 20 to 80 mol %, preferably 30 to 70 mol %, based on the total of all monomers constituting the copolymer.

[0093] As described above, the cycloolefin resin is a polymer obtained by polymerizing or copolymerizing a cycloolefin monomer having a norbornene skeleton, preferably a cycloolefin monomer having a structure represented by general formula (A-1) or (A-2), and examples thereof include the following:

[0094] (1) Ring-opening polymer of cycloolefin monomer (2) Ring-opening copolymers of cycloolefin monomers and copolymerizable monomers capable of ring-opening copolymerization with the cycloolefin monomers. (3) Hydrogenated product of the ring-opening (co)polymer of (1) or (2) above (4) A (co)polymer obtained by cyclizing the ring-opening (co)polymer of (1) or (2) above by the Friedel-Crafts reaction and then hydrogenating the same. (5) Saturated copolymers of cycloolefin monomers and compounds containing unsaturated double bonds (6) Addition copolymers of cycloolefin monomers with vinyl cyclic hydrocarbon monomers and their hydrogenated products (7) Alternating copolymer of cycloolefin monomer and (meth)acrylate The polymers (1) to (7) can be obtained by known methods, for example, the methods described in JP-A-2008-107534 and JP-A-2005-227606. For example, the catalyst and solvent used in the ring-opening copolymerization (2) can be those described in paragraphs 0019 to 0024 of JP-A-2008-107534. The catalyst used in the hydrogenation (3) and (6) can be those described in paragraphs 0025 to 0028 of JP-A-2008-107534. The acidic compound used in the Friedel-Crafts reaction (4) can be those described in paragraph 0029 of JP-A-2008-107534. The catalysts used in the addition polymerizations (5) to (7) above can be those described in, for example, paragraphs 0058 to 0063 of JP-A No. 2005-227606. The alternating copolymerization reaction (7) above can be carried out, for example, by the method described in paragraphs 0071 and 0072 of JP-A No. 2005-227606.

[0095] Among them, the polymers of (1) to (3) and (5) are preferred, and the polymers of (3) and (5) are more preferred. That is, the cycloolefin resin preferably contains at least one of the structural units represented by the following general formula (B-1) and the structural units represented by the following general formula (B-2), and more preferably contains only the structural unit represented by the general formula (B-2) or contains both the structural unit represented by the general formula (B-1) and the structural unit represented by the general formula (B-2). The structural unit represented by the general formula (B-1) is a structural unit derived from the cycloolefin monomer represented by the above-mentioned general formula (A-1), and the structural unit represented by the general formula (B-2) is a structural unit derived from the cycloolefin monomer represented by the above-mentioned general formula (A-2).

[0096] [ka]

[0097] In the general formula (B-1), X represents -CH=CH- or -CH2CH2-. 1 ~R 4 and p are each R in general formula (A-1). 1 ~R 4 and p.

[0098] [ka]

[0099] In the general formula (B-2), X represents -CH=CH- or -CH2CH2-. 5 ~R 6 and p are each R in general formula (A-2). 5 ~R 6 and p.

[0100] The cycloolefin resin according to the present invention may be a commercially available product. Examples of commercially available cycloolefin resins include Arton G (e.g., G7810, etc.), Arton F, Arton R (e.g., R4500, R4900, and R5000, etc.), and Arton RX, all of which are manufactured by JSR Corporation.

[0101] The intrinsic viscosity [η]inh of cycloolefin resin is 0.2 to 5 cm when measured at 30°C. 3 / g, and 0.3 to 3 cm 3 / g, and more preferably in the range of 0.4 to 1.5 cm 3 It is more preferable that the range is / g.

[0102] The number average molecular weight (Mn) of the cycloolefin resin is preferably in the range of 8000 to 100000, more preferably in the range of 10000 to 80000, and even more preferably in the range of 12000 to 50000. The weight average molecular weight (Mw) of the cycloolefin resin is preferably in the range of 20000 to 300000, more preferably in the range of 30000 to 250000, and even more preferably in the range of 40000 to 200000. The number average molecular weight and weight average molecular weight of the cycloolefin resin can be measured in polystyrene equivalent terms by gel permeation chromatography (GPC).

[0103] <Gel permeation chromatography> Solvent: Methylene chloride Column: Shodex K806, K805, K803G (Showa Denko K.K., three columns connected together) Column temperature: 25℃ Sample concentration: 0.1% by mass Detector: RI Model 504 (GL Sciences) Pump: L6000 (Hitachi, Ltd.) Flow rate: 1.0mL / min Calibration curve: A calibration curve was used using 13 samples of standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) in the range of Mw=500 to 2,800,000. It is preferable to use the 13 samples at approximately equal intervals.

[0104] When the intrinsic viscosity [η]inh, number average molecular weight and weight average molecular weight are within the above ranges, the cycloolefin resin has good heat resistance, water resistance, chemical resistance, mechanical properties and moldability into a film.

[0105] The glass transition temperature (Tg) of the cycloolefin resin is usually 110° C. or higher, preferably in the range of 110 to 350° C., more preferably in the range of 120 to 250° C., and even more preferably in the range of 120 to 220° C. If the Tg is 110° C. or higher, deformation under high temperature conditions is easily suppressed. On the other hand, if the Tg is 350° C. or lower, molding is easy and deterioration of the resin due to heat during molding is also easily suppressed.

[0106] The content of the cycloolefin resin is preferably 70% by mass or more, and more preferably 80% by mass or more, based on the mass of the film.

[0107] [2.2] Acrylic resin The acrylic resin according to the present invention is a polymer of an acrylic acid ester or a methacrylic acid ester, and also includes copolymers with other monomers.

[0108] Therefore, the acrylic resin according to the present invention also includes methacrylic resin. Although there is no particular limitation on the resin, it is preferable that the resin contains 50 to 99% by mass of methyl methacrylate units and 1 to 50% by mass of other monomer units copolymerizable therewith.

[0109] Other units constituting the acrylic resin formed by copolymerization include alkyl methacrylates having an alkyl number of 2 to 18 carbon atoms, alkyl acrylates having an alkyl number of 1 to 18 carbon atoms, hydroxyalkyl acrylates such as isobornyl methacrylate and 2-hydroxyethyl acrylate, α,β-unsaturated acids such as acrylic acid and methacrylic acid, acrylamides such as acryloylmorpholine and N-hydroxyphenylmethacrylamide, unsaturated group-containing dicarboxylic acids such as N-vinylpyrrolidone, maleic acid, fumaric acid, and itaconic acid, aromatic vinyl compounds such as styrene and α-methylstyrene, α,β-unsaturated nitriles such as acrylonitrile and methacrylonitrile, maleic anhydride, maleimide, N-substituted maleimide, glutarimide, and glutaric anhydride.

[0110] Examples of copolymerizable monomers forming units other than glutarimide and glutaric anhydride from the above units include monomers corresponding to the above units, such as alkyl methacrylates having an alkyl number of 2 to 18 carbon atoms, alkyl acrylates having an alkyl number of 1 to 18 carbon atoms, isobornyl methacrylate, hydroxyalkyl acrylates such as 2-hydroxyethyl acrylate, α,β-unsaturated acids such as acrylic acid and methacrylic acid, acrylamides such as acryloylmorpholine and N-hydroxyphenylmethacrylamide, unsaturated group-containing divalent carboxylic acids such as N-vinylpyrrolidone, maleic acid, fumaric acid, and itaconic acid, aromatic vinyl compounds such as styrene and α-methylstyrene, α,β-unsaturated nitriles such as acrylonitrile and methacrylonitrile, maleic anhydride, maleimide, and N-substituted maleimide.

[0111] Furthermore, the glutarimide unit can be formed, for example, by reacting an intermediate polymer having a (meth)acrylic acid ester unit with a primary amine (imidizing agent) to effect imidization (see JP-A-2011-26563).

[0112] The glutaric anhydride units can be formed, for example, by heating an intermediate polymer having (meth)acrylic ester units (see Japanese Patent No. 4961164).

[0113] Of the above-mentioned structural units, it is particularly preferable that the acrylic resin according to the present invention contains isobornyl methacrylate, acryloylmorpholine, N-hydroxyphenylmethacrylamide, N-vinylpyrrolidone, styrene, hydroxyethyl methacrylate, maleic anhydride, maleimide, N-substituted maleimide, glutaric anhydride, or glutarimide, from the viewpoint of mechanical strength.

[0114] The acrylic resin according to the present invention preferably has a weight average molecular weight (Mw) in the range of 50,000 to 1,000,000, more preferably in the range of 100,000 to 1,000,000, and particularly preferably in the range of 200,000 to 800,000, from the viewpoints of controlling dimensional changes due to changes in the environmental temperature and humidity atmosphere, and of improving peelability from metal supports during film production, drying properties from organic solvents, heat resistance, and mechanical strength.

[0115] If it is 50,000 or more, the heat resistance and mechanical strength are excellent, and if it is 1,000,000 or less, the peelability from the metal support and the drying property of the organic solvent are excellent.

[0116] The method for producing the acrylic resin according to the present invention is not particularly limited, and any of the known methods such as suspension polymerization, emulsion polymerization, bulk polymerization, or solution polymerization may be used. Here, as the polymerization initiator, a normal peroxide-based or azo-based one can be used, and a redox-based one can also be used. The polymerization temperature can be within the range of 30 to 100°C in suspension or emulsion polymerization, and within the range of 80 to 160°C in bulk or solution polymerization. In order to control the reduced viscosity of the obtained copolymer, the polymerization can also be carried out using an alkyl mercaptan or the like as a chain transfer agent.

[0117] The glass transition temperature Tg of the acrylic resin is preferably within the range of 80 to 120° C. from the viewpoint of maintaining the mechanical strength of the film.

[0118] The acrylic resin according to the present invention may be a commercially available product. For example, Delpet 60N, 80N, 980N, SR8200 (all manufactured by Asahi Kasei Chemicals Corporation), Dianale BR52, BR80, BR83, BR85, BR88, EMB-143, EMB-159, EMB-160, EMB-161, EMB-218, EMB-229, EMB-270, EMB-273 (all manufactured by Mitsubishi Rayon Co., Ltd.), KT75, TX400S, IPX012 (all manufactured by Denki Kagaku Kogyo Co., Ltd.), etc. Two or more types of acrylic resins may be used in combination.

[0119] The acrylic resin according to the present invention preferably contains an additive, and an example of the additive is acrylic particles (rubber elastomer particles) described in International Publication No. 2010 / 001668, which are preferably contained in order to improve the mechanical strength of the film and adjust the dimensional change rate. Examples of commercially available products of such multilayered acrylic granular composites include "Metabrene W-341" manufactured by Mitsubishi Rayon Co., Ltd., "Kane Ace" manufactured by Kaneka Corporation, "Paraloid" manufactured by Kureha Corporation, "Acryloid" manufactured by Rohm and Haas Co., Ltd., "Staphyloid" manufactured by Aica Corporation, Chemisnow MR-2G, MS-300X (all manufactured by Soken Chemical & Engineering Co., Ltd.), and "Parapet SA" manufactured by Kuraray Co., Ltd., and these can be used alone or in combination.

[0120] The volume average particle size of the acrylic particles is 0.35 μm or less, preferably in the range of 0.01 to 0.35 μm, and more preferably in the range of 0.05 to 0.30 μm. If the particle size is equal to or more than a certain value, the film can be easily stretched under heating, and if the particle size is equal to or less than a certain value, the transparency of the obtained film is not easily impaired.

[0121] From the viewpoint of flexibility, the optical film of the present invention preferably has a flexural modulus (JIS K7171) of 1.5 GPa or less. This flexural modulus is more preferably 1.3 GPa or less, and even more preferably 1.2 GPa or less. This flexural modulus varies depending on the type and amount of the acrylic resin and rubber elastomer particles in the film, and for example, the higher the content of the rubber elastomer particles, the smaller the flexural modulus generally becomes. In addition, the flexural modulus generally becomes smaller when a copolymer of alkyl methacrylate and alkyl acrylate is used as the acrylic resin than when a homopolymer of alkyl methacrylate is used.

[0122] [3] Other ingredients The optical film of the present invention may further contain other components other than those described above within a range that does not impair the effects of the present invention. Examples of other components include matting agents, ultraviolet absorbers, retardation adjusters (retardation increasers, retardation decreasers), plasticizers, antioxidants, light stabilizers, antistatic agents, release agents, and thickeners. Among these, it is preferable that the optical film contains a matting agent from the viewpoint of imparting unevenness to the surface of the optical film and imparting appropriate slipperiness.

[0123] (Matte agent) The matting agent is a fine particle. The fine particle may be an inorganic fine particle or a resin fine particle. Examples of the inorganic fine particle include fine particles of inorganic compounds such as silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, and calcium phosphate. Among them, the inorganic fine particle is preferably silicon dioxide fine particle from the viewpoint of not increasing the haze of the optical film and effectively reducing the friction coefficient.

[0124] Examples of silicon dioxide fine particles include Aerosil 200V, Aerosil R972V, and Aerosil R812 (all manufactured by Nippon Aerosil Co., Ltd.).

[0125] Examples of resin particles include silicone resin, fluororesin, acrylic resin, etc. Among them, silicone resin particles are preferred, and resin particles having a three-dimensional network structure are particularly preferred. Examples of resin particles include Tospearl 103, 105, 108, 120, 145, 3120, and 240 (all manufactured by Toshiba Silicone Co., Ltd.).

[0126] The average particle size of the primary particles of the fine particles is preferably in the range of 0.005 to 0.4 μm, and more preferably in the range of 0.01 to 0.3 μm. These fine particles may be contained as secondary aggregates having a particle size in the range of 0.05 to 0.3 μm.

[0127] The content of the fine particles is preferably in the range of 0.01 to 3.0% by mass, and more preferably in the range of 0.01 to 2.0% by mass, relative to the optical film. The dynamic friction coefficient of the surface of the optical film is preferably in the range of 0.2 to 1.0.

[0128] [4] Method for manufacturing optical film [4.1] Physical properties of optical films (Phase difference Ro) For example, from the viewpoint of using the optical film as a λ / 4 retardation film, the in-plane retardation Ro measured at a measurement wavelength of 550 nm under an environment of 23°C and 55% RH is preferably in the range of 100 to 170 nm, more preferably in the range of 130 to 150 nm.

[0129] Ro is defined by the following formula.

[0130] Formula (1): Ro = (n x -n y )×d (In formula (1), n x represents the refractive index in the in-plane slow axis direction of the film (the direction in which the refractive index is maximum), and n y represents the refractive index in a direction perpendicular to the in-plane slow axis of the film, and d represents the thickness of the film (nm). The in-plane slow axis of the optical film can be confirmed by an automatic birefringence meter Axoscan (Axo Scan Mueller Matrix Polarimeter, manufactured by Axometrics, Inc.) When the optical film is used as a λ / 4 retardation film, the angle of the in-plane slow axis of the optical film with respect to the width direction of the optical film is preferably in the range of 40 to 50°, more preferably in the range of 43 to 47°.

[0131] Ro can be measured by the following method.

[0132] 1) The optical film is conditioned for 24 hours in an environment of 23°C and 55% RH. The average refractive index of this film is measured with an Abbe refractometer, and the thickness d is measured with a commercially available micrometer.

[0133] 2) After humidity conditioning, the retardation Ro of the film at a measurement wavelength of 550 nm is measured in an environment of 23° C. and 55% RH using an automatic birefringence meter Axoscan (Axo Scan Mueller Matrix Polarimeter, manufactured by Axometrics).

[0134] The retardation Ro of the optical film can be adjusted, for example, by the monomer composition of the cycloolefin resin and the stretching conditions.

[0135] (Residual Solvent Amount) The optical film is preferably produced by a solution casting method, and may further contain a residual solvent. The amount of the residual solvent is preferably 700 ppm or less, more preferably in the range of 30 to 700 ppm, relative to the optical film. The content of the residual solvent can be adjusted by the drying conditions of the dope cast on the support in the production process of the optical film.

[0136] The amount of residual solvent in the optical film can be measured by headspace gas chromatography. In the headspace gas chromatography method, a sample is sealed in a container, heated, and the container is filled with volatile components, and the gas in the container is quickly injected into a gas chromatograph, and mass analysis is performed to identify the compounds and quantify the volatile components. In the headspace method, the gas chromatograph makes it possible to observe all peaks of the volatile components, and by using an analysis method that utilizes electromagnetic interactions, it is also possible to quantify volatile substances, monomers, etc. with high accuracy.

[0137] (Thickness) The thickness of the optical film of the present invention is not particularly limited, but is preferably in the range of 10 to 80 μm, and more preferably in the range of 10 to 60 μm.

[0138] [4.2] Manufacturing method of optical film The optical film of the present invention can be produced through the steps of 1) preparing a dope containing the above cycloolefin resin or acrylic resin, the above dye compound, and a solvent, 2) casting the obtained dope on a support, drying and peeling the dope to obtain a casting film, and 3) stretching the obtained casting film. The optical film of the present invention may also be produced through the steps of 4) drying the stretched casting film, 5) cutting both ends of the obtained optical film and embossing the film, and 6) winding the film.

[0139] Regarding step 1) (dope preparation step) A cycloolefin resin or an acrylic resin, and a dye compound are dissolved or dispersed in a solvent to prepare a dope.

[0140] The solvent used for the dope includes an organic solvent (good solvent) capable of dissolving at least the cycloolefin resin. Examples of the good solvent include chlorine-based organic solvents such as methylene chloride; and non-chlorine-based organic solvents such as methyl acetate, ethyl acetate, acetone, and tetrahydrofuran. Among them, methylene chloride is preferable.

[0141] The solvent used in the dope may further contain a poor solvent. Examples of the poor solvent include linear or branched aliphatic alcohols having 1 to 4 carbon atoms. When the ratio of alcohol in the dope is high, the film-like material is likely to gel and is likely to be easily peeled off from the metal support. Examples of linear or branched aliphatic alcohols having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Among these, ethanol is preferred because of the stability of the dope, its relatively low boiling point, and its good drying property.

[0142] Regarding process 2) (casting process) The obtained dope is cast onto a support by being discharged from a casting die.

[0143] The solvent is evaporated from the dope cast on the support until it can be peeled off from the support by a peel roll. Methods for evaporating the solvent include a method of blowing air on the cast dope, a method of transferring heat from the back side of the support by a liquid, and a method of transferring heat from the front and back sides by radiant heat.

[0144] Thereafter, the solvent is evaporated to obtain a cast film, which is peeled off by a peeling roll.

[0145] The residual solvent amount of the casting film on the support at the time of peeling may be, for example, in the range of 50 to 120 mass %, depending on the drying conditions and the length of the support. If the casting film is peeled off in a state where the residual solvent amount is large, the casting film becomes too soft, and the flatness is easily lost at the time of peeling, and wrinkles and vertical streaks are easily generated due to the peeling tension. Therefore, the residual solvent amount at the time of peeling is determined taking these points into consideration. The residual solvent amount is defined by the following formula.

[0146] Residual solvent amount (mass%)=(mass of cast membrane before heat treatment-mass of cast membrane after heat treatment) / (mass of cast membrane after heat treatment)×100 The heat treatment for measuring the amount of residual solvent is performed at 115° C. for 1 hour.

[0147] Regarding step 3 (stretching process) The cast membrane obtained by peeling it off from the support is stretched.

[0148] The stretching may be performed according to the desired optical properties, and it is preferable to stretch in one or more directions among the width direction (TD direction), the machine direction (MD direction), and the oblique direction. For example, when producing an optical film that functions as a λ / 4 retardation film, it is preferable to stretch in the oblique direction.

[0149] The stretching ratio depends on the desired optical properties, but for example, when used as a λ / 4 retardation film, it is preferably in the range of 1.05 to 4.0 times, more preferably 1.5 to 3.0 times.

[0150] The stretching ratio (times) is defined as the stretching direction size of the film after stretching / the stretching direction size of the film before stretching. When biaxial stretching is performed, it is preferable to set the above-mentioned stretching ratios for each of the TD and MD directions.

[0151] The stretching temperature (drying temperature during stretching) is preferably in the range of (Tg+2) to (Tg+50)° C., more preferably in the range of (Tg+5) to (Tg+30)° C., when the glass transition temperature of the cycloolefin resin is Tg, as described above. When the stretching temperature is (Tg+2)° C. or higher, the solvent is easily volatilized appropriately, making it easy to adjust the stretching tension to an appropriate range, and when the stretching temperature is (Tg+50)° C. or lower, the solvent does not volatilize too much, making it difficult for stretchability to be impaired. As described above, it is preferable to measure the (a) ambient temperature, such as the temperature inside the stretching machine, for the stretching temperature.

[0152] The amount of residual solvent in the film at the start of stretching is preferably similar to the amount of residual solvent in the film at the time of peeling, for example, preferably in the range of 20 to 30% by mass, more preferably in the range of 25 to 30% by mass.

[0153] The stretching in the TD direction (width direction) of the film-like material can be performed, for example, by fixing both ends of the film-like material with clips or pins and widening the interval between the clips or pins in the traveling direction (tenter method). The stretching in the MD direction of the film-like material can be performed, for example, by providing a peripheral speed difference between a plurality of rolls and utilizing the roll peripheral speed difference therebetween (roll method). In particular, the tenter method in which both ends of the cast film are held by clips or the like and stretched is preferred in order to improve the flatness and dimensional stability of the film. It is preferred to stretch the cast film in both the MD direction and the TD direction, thereby stretching it in a direction obliquely intersecting the MD direction and the TD direction (oblique stretching).

[0154] Regarding step 4 (drying process) The stretched cast film is further dried to obtain an optical film.

[0155] The casting film can be dried while being transported by a plurality of transport rolls (e.g., a plurality of transport rolls arranged in a staggered manner when viewed from the side). The drying means is not particularly limited, and hot air, infrared rays, a heating roll, or microwaves can be used. Hot air drying is preferred from the viewpoint of simplicity.

[0156] Regarding step 5) (cutting and embossing process) Both ends of the obtained optical film in the width direction are cut off. The cutting of both ends of the optical film can be performed by a slitter.

[0157] Next, embossing (knurling) is performed on both ends in the width direction of the optical film. The embossing can be performed by pressing a heated embossing roller against both ends of the optical film. Fine irregularities are formed on the surface of the embossing roller, and by pressing the embossing roller against both ends of the optical film, irregularities are formed on both ends. This type of embossing can minimize winding misalignment and blocking (films sticking together) in the subsequent winding process.

[0158] Regarding step 6 (winding process) The resulting optical film is then wound up to obtain a roll.

[0159] That is, the optical film is wound around a core while being transported to form a roll. The optical film can be wound using any method that uses a commonly used winder, and includes a tension control method such as a constant torque method, a constant tension method, a taper tension method, or a program tension control method with constant internal stress.

[0160] The length of the optical film wound in the roll is preferably in the range of 1000 to 7200 m, and the width of the optical film is preferably in the range of 1000 to 3000 mm.

[0161] [5] Other functional layers The optical film of the present invention preferably has a functional layer, and the functional layer preferably contains a compound having a structure represented by the general formula (1). Examples of the functional layer include a hard coat layer, an antistatic layer, an antireflection layer, a slippery layer, an adhesive layer, an antiglare layer, and a barrier layer. When the optical film of the present invention is incorporated into an organic EL image display device, it is preferable to provide a hard coat layer in order to improve scratch resistance.

[0162] [5.1] Hard coat layer The hard coat layer used in the present invention preferably contains an actinic radiation curable resin from the viewpoint of excellent mechanical film strength (scratch resistance, pencil hardness). That is, the layer is mainly composed of a resin that is cured through a crosslinking reaction by irradiation with actinic radiation (also called active energy radiation) such as ultraviolet rays or electron beams. As the actinic radiation curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and the actinic radiation curable resin layer is formed by curing the resin by irradiation with actinic radiation such as ultraviolet rays or electron beams. Representative examples of the actinic radiation curable resin include ultraviolet curable resins and electron beam curable resins, and resins that are cured by ultraviolet irradiation are particularly preferred from the viewpoint of excellent mechanical film strength (scratch resistance, pencil hardness). As the ultraviolet curable resin, for example, ultraviolet curable acrylate resins, ultraviolet curable urethane acrylate resins, ultraviolet curable polyester acrylate resins, ultraviolet curable epoxy acrylate resins, ultraviolet curable polyol acrylate resins, ultraviolet curable epoxy resins, etc. are preferably used, and among them, ultraviolet curable acrylate resins are preferred.

[0163] Commercially available products include Adeka Optomer N series, Sunrad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612 (all manufactured by Sanyo Chemical Industries, Ltd.), Aronix M-6100, M-8030, M-8060, Aronix M-215, Aronix M-315, Aronix M-313, Aronix M-327 (all manufactured by Toagosei Co., Ltd.), NK-ester A-TMM-3L, NK-ester AD-TMP, NK-ester ATM-35E, NK-ester A-DOG, NK-ester A-IBD-2E, A-9300, A-9300-1CL (all manufactured by Shin-Nakamura Chemical Co., Ltd.), and PE-3A (manufactured by Kyoeisha Chemical). The above actinic radiation curable resins may be used alone or in combination of two or more kinds.

[0164] In addition, the hard coat layer preferably contains a photopolymerization initiator to promote the curing of the actinic radiation curable resin. The amount of the photopolymerization initiator is preferably in the range of photopolymerization initiator:actinic radiation curable resin=20:100 to 0.01:100 in mass ratio. Specific examples of the photopolymerization initiator include, but are not limited to, alkylphenones, acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof.

[0165] As such a photopolymerization initiator, a commercially available product may be used, and preferred examples thereof include Irgacure 184, Irgacure 907, and Irgacure 651, all of which are manufactured by BASF Japan Ltd.

[0166] From the viewpoints of improving the hard coat properties and improving the transparency of the optical film, the thickness of the hard coat layer is preferably within the range of 0.1 to 50 μm, and more preferably within the range of 1 to 20 μm. The method for forming the hard coat layer is not particularly limited, and examples thereof include a method in which a coating liquid for forming a hard coat layer containing the above-mentioned components is prepared, the coating liquid is applied with a wire bar or the like, and the coating liquid is cured with heat or ultraviolet light to form a hard coat layer. In order to further improve light resistance and provide scratch resistance, it is preferable that the hard coat layer contains a compound having a structure represented by the general formula (1) according to the present invention. The compound is preferably contained in an amount of 0.1 to 40% by mass, more preferably 0.1 to 20% by mass, based on the ultraviolet curable resin.

[0167] [6] Polarizing plate The polarizing plate of the present invention has a polarizer and the optical film of the present invention disposed on at least one surface of the polarizer.

[0168] FIG. 1 is a cross-sectional view showing the structure of a polarizing plate 100. As shown in FIG. As shown in FIG. 1, the polarizing plate 100 of the present invention may have a polarizer 101, an optical film 102 of the present invention arranged on one side thereof, an opposing film 103 arranged on the other side thereof, and two adhesive layers 104 arranged between the polarizer 101 and the optical film 102, and between the polarizer 101 and the opposing film 103.

[0169] (Regarding polarizer 101) The polarizer 101 is an element that transmits only light polarized in a certain direction, and is a stretched polyvinyl alcohol film doped with iodine or a dichroic dye.

[0170] The thickness of the polarizer 101 is in the range of 5 to 40 μm, preferably in the range of 5 to 30 μm, and particularly preferably in the range of 5 to 20 μm.

[0171] (Regarding Optical Film 102) The optical film 102 can function as a retardation film, for example, a λ / 4 retardation film used in a circular polarizing plate of an organic EL image display device.

[0172] In the plane of the optical film 102, the angle that the in-plane slow axis of the optical film 102 makes with one side of the rectangular outer shape of the film is preferably in the range of 30 to 60°, more preferably 45°. The side corresponds to the width direction of the long optical film 102. The angle that the in-plane slow axis of the optical film 102 makes with the absorption axis (or transmission axis) of the polarizer 101 is preferably in the range of 30 to 60°, more preferably 45°.

[0173] Depending on the application, the optical film 102 may further have another layer (for example, a hard coat layer, a low refractive index layer, or an antireflection layer) arranged on the surface opposite to the polarizer 101. The optical film 102 may further have an easy-adhesion layer (not shown) arranged on the surface on the polarizer 101 side.

[0174] (Regarding the opposing film 103) The facing film 103 may be the optical film of the present invention or another optical film (i.e., a protective film). More preferably, the optical film of the present invention is used and has a hard coat layer on the outermost surface.

[0175] Examples of commercially available protective films include commercially available cellulose ester films (e.g., Konica Minolta TAC KC8UX, KC5UX, KC4UX, KC8UCR3, KC4SR, KC4BR, KC4CR, KC4DR, KC4FR, KC4KR, KC8UY, KC6UY, KC4UY, KC4UE, KC8UE, KC8UY-HA, KC2UA, KC4 UA, KC6UA, KC8UA, KC2UAH, KC4UAH, KC6UAH, all manufactured by Konica Minolta, Inc., Fujitac T40UZ, Fujitac T60UZ, Fujitac T80UZ, Fujitac TD80UL, Fujitac TD60UL, Fujitac TD40UL, Fujitac R02, Fujitac R06, all manufactured by Fujifilm Corporation.

[0176] As commercially available cycloolefin films, various grades of cycloolefin polymer (COP) molded products - ZeonorFilm (R) manufactured by Zeon Corporation are preferably used.

[0177] The thickness of the opposing film 103 can be, for example, in the range of 5 to 100 μm, and preferably in the range of 40 to 80 μm.

[0178] (Regarding adhesive layer 104) Adhesive layers 104 may be disposed between the polarizer 101 and the optical film 102, and between the polarizer 101 and the facing film 103, respectively.

[0179] The adhesive layer 104 may be a layer obtained from a water-based adhesive, which will be described later, or may be a layer of a cured product of an ultraviolet-curable adhesive.

[0180] The thickness of adhesive layer 104 is not particularly limited, but may be, for example, in the range of 0.01 to 10 μm, and preferably about 0.01 to 5 μm.

[0181] The polarizing plate 100 may be in a long shape, or may be in a sheet shape obtained by cutting a long polarizing plate along the width direction.

[0182] (Physical Properties) (T1 / T2) When an aluminum reflective material is laminated on the optical film of a polarizing plate via an adhesive layer, the reflectance of the polarizing plate at a wavelength of 460 nm is T1 (%) and the reflectance of the polarizing plate at a wavelength of 650 nm is T2 (%). It is preferable that the polarizing plate satisfies the following formula (2).

[0183] Formula (2):0 <T1 / T2<2.6 When T1 / T2 is less than 2.6, the reflectance of light with a wavelength of 460 nm is not too high, i.e., the leakage of reflected light in the vicinity of the wavelength can be suppressed, so that, for example, the color of reflected light in an organic EL image display device can be improved. Also, when T1 / T2 is more than 0, for example, the emission in the above wavelength range in an organic EL image display device is less likely to be inhibited by the dye compound, so that a decrease in brightness can be suppressed. It is more preferable that T1 / T2 is 2.5 or less.

[0184] (color difference ΔE(a * b * )) In addition, the color difference ΔE(a * b * ) is preferably less than 25, and more preferably less than 20. When the color difference ΔE(a*b*) of the polarizing plate is within the above range, for example, the color of reflected light in an organic EL image display device can be improved.

[0185] Polarizing plate T1 / T2 and color difference ΔE(a * b * ) can be measured by the following procedure.

[0186] 1) A polarizing plate sample is prepared by laminating an aluminum reflective material on the optical film of the polarizing plate via an adhesive layer. The adhesive is an acrylic adhesive.

[0187] 2) Spectral reflectance and color difference ΔE(a * b * ) is measured using a spectrophotometer (Konica Minolta CM3700d) by the SCI method.

[0188] Polarizing plate T1 / T2 and color difference ΔE(a * b * ) can be adjusted by the type and content of the dye compound represented by general formula (1).

[0189] (Method of manufacturing polarizing plate 100) The polarizing plate 100 can be obtained by a process of bonding a polarizer 101 and an optical film 102 of the present invention together via an adhesive. As the adhesive, a water-based adhesive or an ultraviolet-curing adhesive is used.

[0190] <Water-based adhesive> Examples of the water-based adhesive include water-based adhesives containing polyvinyl alcohol resins (such as an aqueous solution of fully saponified polyvinyl alcohol).

[0191] <UV-curing adhesive> The ultraviolet-curable adhesive composition may be a photoradical polymerization composition, a photocationic polymerization composition, or a hybrid composition using both.

[0192] Examples of photoradical polymerization compositions include a composition containing a radical polymerizable compound containing a polar group such as a hydroxy group or a carboxy group, and a radical polymerizable compound not containing a polar group, as described in JP-A-2008-009329.

[0193] The radical polymerizable compound is preferably a compound having a radical polymerizable ethylenically unsaturated bond.Preferred examples of the compound having a radical polymerizable ethylenically unsaturated bond include compounds having a (meth)acryloyl group.Examples of the compound having a (meth)acryloyl group include N-substituted (meth)acrylamide compounds and (meth)acrylate compounds.(Meth)acrylamide means acrylamide or methacrylamide.

[0194] Examples of photocationic polymerization compositions include ultraviolet-curable adhesive compositions containing (α) a cationically polymerizable compound, (β) a photocationic polymerization initiator, (γ) a photosensitizer that exhibits maximum absorption at wavelengths longer than 380 nm, and (δ) a naphthalene-based photosensitizer assistant, as disclosed in JP2011-028234A.

[0195] An example in which an ultraviolet-curing adhesive is used will be described below. The polarizing plate 100 of the present invention can be obtained through 1) a step of performing a pretreatment for easy adhesion on the adhesive surfaces of the optical film and the opposing film (pretreatment step), 2) a step of bonding the polarizer and the optical film (or the opposing film) via an ultraviolet adhesive, and 3) a step of irradiating the laminate obtained by bonding with ultraviolet rays to cure the ultraviolet adhesive (curing step).

[0196] (1) Pretreatment process The adhesive surface between the optical film and the polarizer of the opposing film is subjected to an adhesion enhancing treatment. Examples of the adhesion enhancing treatment include a corona treatment and a plasma treatment.

[0197] (2) Bonding process The ultraviolet-curable adhesive is applied to at least one of the polarizer and the optical film (or the opposing film). The method for applying the ultraviolet-curable adhesive is not particularly limited, and may be, for example, a doctor blade, a wire bar, a die coater, a comma coater, a gravure coater, or the like.

[0198] Then, the polarizer and the optical film or the counter film are bonded together via an ultraviolet-curing adhesive. Then, both sides of the laminate are pressed by sandwiching them with a pressure roller or the like. The pressure roller can be made of metal or rubber.

[0199] (3) Curing process Next, the laminate bonded together via the ultraviolet-curing adhesive is irradiated with ultraviolet light to cure the ultraviolet-curing adhesive. As a result, the polarizer and the optical film or the opposing film are bonded together via the ultraviolet-curing adhesive. The ultraviolet-curing adhesive on one side of the polarizer and the ultraviolet-curing adhesive on the other side of the polarizer may be cured sequentially or simultaneously. From the viewpoint of increasing the manufacturing efficiency of the polarizing plate, it is preferable to simultaneously cure the ultraviolet-curing adhesive on one side of the polarizer and the ultraviolet-curing adhesive on the other side of the polarizer.

[0200] The ultraviolet irradiation conditions may be any conditions that allow the ultraviolet curing adhesive to cure, for example, an integrated light amount of 50 to 1500 mJ / cm 2 The range is preferably 100 to 500 mJ / cm 2 It is more preferable that the range is .

[0201] The line speed during the manufacture of the polarizing plate depends on the curing time of the adhesive, but is preferably in the range of 1 to 500 m / min, and more preferably in the range of 5 to 300 m / min. If the line speed is 1 m / min or more, the productivity can be easily increased and damage to the optical film and the opposing film can be reduced. Also, if the line speed is 500 m / min or less, the ultraviolet-curable adhesive is sufficiently cured, and good adhesion can be easily obtained.

[0202] Thus, in the curing process, a high-temperature environment may be created due to ultraviolet irradiation, heating for curing promotion, etc. Even if the adhesive is a water-based adhesive, a high-temperature environment may be created due to heating for adhesion promotion or drying the adhesive.

[0203] In contrast, the optical film of the present invention has excellent light resistance and durability, and therefore a polarizing plate with suppressed light leakage can be obtained even in a high-temperature environment during adhesion of the polarizer and the optical film. By suppressing light leakage from the polarizing plate, it is possible to suppress slight light leakage due to external light reflection during black display in an organic EL image display device having the polarizing plate.

[0204] [7] Image display devices The optical film of the present invention can be used as an optical film (retardation film, protective film) for an image display device such as an organic EL image display device or a liquid crystal display device. In particular, the optical film of the present invention can be preferably used as a retardation film (λ / 4 retardation film) for an organic EL image display device.

[0205] [7.1] Organic EL image display device FIG. 2 is an exploded cross-sectional view of the organic EL image display device 200. As shown in FIG.

[0206] The organic EL image display device 200 has an organic EL element 300 (display cell), a polarizing plate 100 (circular polarizing plate), and an adhesive layer 400 disposed therebetween.

[0207] An organic EL element 300 has, in this order, a metal electrode 302, a light-emitting layer 303, a transparent electrode (ITO or the like) 304, and a sealing layer 305 on a substrate 301 such as glass or polyimide. The metal electrode 302 may be composed of a reflective electrode and a transparent electrode.

[0208] The metal electrode 302 can function as a cathode. For the metal electrode 302, in order to facilitate electron injection and increase the light emission efficiency, it is preferable to use a material with a small work function, and typically Mg-Ag or Al-Li is used.

[0209] The light-emitting layer 303 is a laminate of organic thin films, and can be, for example, a laminate of a hole-injection layer made of a triphenylamine derivative or the like and a light-emitting layer made of a fluorescent organic solid such as anthracene, a laminate of such a light-emitting layer and an electron-injection layer made of a perylene derivative or the like, or a laminate of these hole-injection layer, light-emitting layer, and electron-injection layer.

[0210] The transparent electrode 304 may function as an anode. The transparent electrode 304 may typically be made of a transparent conductor such as indium tin oxide (ITO).

[0211] By applying a voltage between the metal electrode 302 and the transparent electrode 304, holes and electrons are injected into the light-emitting layer 303. The energy generated by the recombination of these holes and electrons excites the fluorescent material, and when the excited fluorescent material returns to its ground state, it emits light, thereby emitting light.

[0212] The polarizing plate 100 is disposed on the viewing side surface of the organic EL element 300. The polarizing plate 100 is the above-mentioned polarizing plate 100 (see FIG. 1), and is disposed such that the optical film 102 (λ / 4 retardation film) is located between the organic EL element 301 and the polarizer 101. As described above, they are bonded together such that the angle between the transmission axis (or absorption axis) of the polarizer 101 and the in-plane slow axis of the optical film 102 is preferably 45° (or 135°).

[0213] The opposing film 103 preferably further has a hard coat layer (not shown) disposed on its viewing side surface (the surface opposite to the polarizer 101). The hard coat layer not only prevents scratches on the surface of the organic EL image display device, but also reduces warping of the polarizing plate 100. An antireflection layer may further be formed on the hard coat layer.

[0214] The adhesive layer 400 is disposed between the organic EL element 300 and the polarizing plate 100 to bond them together. Examples of adhesives constituting the adhesive layer 400 include thermosetting adhesives (epoxy-based thermosetting adhesives, urethane-based thermosetting adhesives, acrylic-based thermosetting adhesives, etc.), hot melt adhesives, etc. (rubber-based hot melt adhesives, polyester-based hot melt adhesives, polyolefin-based hot melt adhesives, ethylene-vinyl acetate resin-based hot melt adhesives, polyurethane resin hot melt adhesives, etc.).

[0215] (action) In such an organic EL image display device 200, when a voltage is applied between the metal electrode 302 and the transparent electrode 304, electrons are injected into the light-emitting layer 303 from the metal electrode 302 which serves as a cathode, and holes are injected from the transparent electrode 304 which serves as an anode, and the two are recombined in the light-emitting layer 303, thereby emitting visible light corresponding to the light-emitting characteristics of the light-emitting layer 303. The light generated in the light-emitting layer 303 is extracted to the outside via the transparent electrode 304 and the polarizing plate 100, either directly or after being reflected by the metal electrode 302.

[0216] The light-emitting layer 303 is formed of an extremely thin film having a thickness of about 10 nm. Therefore, the light-emitting layer 303, like the transparent electrode 304, transmits light almost completely. As a result, when light is not emitted, light that enters from the outside of the organic EL image display device 200, passes through the sealing layer 305, the transparent electrode 304, and the light-emitting layer 303, and reaches the metal electrode 302 is reflected by the metal electrode 302, passes through the light-emitting layer 303, the transparent electrode 302, and the sealing layer 305 again, and attempts to exit to the front side of the organic EL device 200. At this time, the optical film 102 suppresses the light reflected by the metal electrode 302 from leaking out to the front side of the organic EL image display device 200, thereby reducing external light reflection.

[0217] That is, when no light is emitted, half of the external light incident from outside the organic EL image display device 200 due to indoor lighting or the like is absorbed by the polarizer 101 of the polarizing plate 100, while the remaining half is not absorbed and is transmitted as linearly polarized light and enters the optical film 102 (λ / 4 retardation film). Since the transmission axis of the polarizer 101 and the in-plane slow axis of the optical film 102 intersect at 45° (or 135°), the light that enters the optical film 102 is converted into circularly polarized light.

[0218] The circularly polarized light emitted from the optical film 102 is mirror-reflected by the metal electrode 302 of the organic EL element 300, and the phase is inverted by 180 degrees to become reverse-circularly polarized light. This reflected light is converted into linearly polarized light perpendicular to the transmission axis of the polarizer 101 (parallel to the absorption axis) by entering the optical film 102, and is therefore absorbed by the polarizer 101, and can be prevented from being emitted to the outside.

[0219] In the present invention, an optical film 102 containing a specific dye compound is used. As a result, the optical film 102 can convert light in a specific wavelength range (a cycloolefin resin film not containing a dye compound cannot convert light into a desired linearly polarized light) into linearly polarized light perpendicular to the transmission axis of the polarizer 101 (parallel to the absorption axis). This makes it possible to suppress a decrease in the color of the reflected light caused by the reflected light in the specific wavelength range leaking through the transmission axis of the polarizer 101. Furthermore, even though the optical film 102 contains a dye compound, it has excellent light resistance and can suppress display unevenness caused by this. EXAMPLES

[0220] The present invention will be described in detail below with reference to examples, but the present invention is not limited thereto. In the examples, the terms "parts" and "%" are used, but they represent "parts by mass" or "% by mass" unless otherwise specified.

[0221] Example 1 1. Optical film materials (1) Cycloolefin resin <Synthesis of cycloolefin resin 1> 100 parts by mass of purified toluene and 100 parts by mass of norbornene carboxylic acid methyl ester (see structural formula A below) were charged into the reaction vessel. Next, 25 mmol% (relative to monomer mass) of ethylhexanoate-Ni dissolved in toluene, 0.225 mol% (relative to monomer mass) of tri(pentafluorophenyl)boron dissolved in toluene, and 0.25 mol% (relative to monomer mass) of triethylaluminum dissolved in toluene were charged into the reaction vessel and reacted for 18 hours while stirring at room temperature. After the reaction was completed, the reaction mixture was charged into an excess of ethanol to generate a polymer precipitate. The precipitate was purified, and the obtained solid was dried in a vacuum at 65°C for 24 hours to obtain a cycloolefin resin (P-1) (weight average molecular weight Mw: 140,000, Tg: 140°C). The weight average molecular weight was measured by the method described above.

[0222] [ka]

[0223] (2) Pigment compounds The exemplary dye compounds and comparative compounds shown in Table I were prepared, and the energy levels (eV) of the HOMO were calculated.

[0224] The HOMO energy levels of the exemplary dye compounds having a structure represented by general formula (1) and the comparative compounds can be calculated by molecular orbital calculation software using B3LYP as a functional and 6-31G(d) as a basis function as a calculation method. There are no particular limitations on the software, and any software can be used to obtain the energy levels in the same manner.

[0225] In the present invention, calculations were performed using Gaussian09 (Revision C.01, MJ Frisch, et al., Gaussian, Inc., 2010.) manufactured by Gaussian, Inc., USA, as molecular orbital calculation software. The calculated HOMO energy level values ​​are shown in Table I.

[0226] <Synthesis example of illustrative dye compounds>

[0227] <Example dye compound 9> [ka]

[0228] 1 g of compound (9-1) and 0.277 g of malononitrile were weighed into a 100 mL three-head flask, and 18 mL of toluene was added to dissolve. Next, 0.332 g of morpholine was added dropwise, and the mixture was heated and refluxed for 4 hours. After the reaction was completed, the solvent was removed under reduced pressure, and 5 mL of methanol was added and stirred in a suspended state. The precipitate was filtered and dried to obtain 0.33 g (yield 28%) of powder of exemplary dye compound 9. The structure was confirmed by NMR.

[0229] <Example dye compound 23> [ka]

[0230] 1 g of compound (23-1) and 0.497 g of malononitrile were weighed into a 100 mL three-head flask, and 40 mL of toluene was added to dissolve. Next, 0.596 g of morpholine was added dropwise, and the mixture was heated and refluxed for 4 hours. After the reaction was completed, the solvent was removed under reduced pressure, and 5 mL of methanol was added and stirred in a suspended state. The precipitate was filtered and dried to obtain 0.24 g (yield 18%) of powder of exemplary dye compound 23. The structure was confirmed by NMR.

[0231] [ka]

[0232] (Measurement of maximum absorption wavelength) The maximum absorption wavelengths of the above compounds were determined by measuring the absorption spectrum of the dye compound in dichloromethane using an ultraviolet-visible spectrophotometer UV-2450 manufactured by Shimadzu Corporation, and are shown in Table II. In the present invention, the "maximum absorption wavelength" refers to the wavelength (nm) showing the maximum absorbance (absorption intensity) in the absorption spectrum of the compound obtained by measuring the absorption spectrum of the compound.

[0233] [Table 1]

[0234] [Table 2]

[0235] 2. Preparation and evaluation of optical films <Preparation of Optical Film 101> (Preparation of microparticle additive solution) The following components were mixed and stirred for 50 minutes in a dissolver, then dispersed in a Manton-Gaulin. Further, the mixture was dispersed in an attritor so that the secondary particles had a specified particle size. The mixture was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive liquid.

[0236] Fine particles (Aerosil R812: manufactured by Nippon Aerosil Co., Ltd., primary average particle size: 7 nm, apparent specific gravity 50 g / L): 4 parts by mass Dichloromethane: 48 parts by weight Ethanol: 48 parts by weight

[0237] (Preparation of dope) The following components were put into a sealed container while being thoroughly stirred, and then heated to 80° C. and kept for 1 hour. Then, this was cooled to 30° C., and filtered through a filter with a pore size of 5 μm to obtain dope A-1.

[0238] Cycloolefin resin 1: 100 parts by mass Dichloromethane: 302 parts by weight Ethanol: 18 parts by weight Exemplary dye compound 1: 0.1 parts by weight Fine particle additive liquid: 10 parts by mass

[0239] (Preparation of Optical Film 101) The prepared dope was cast from a casting die onto an endless metal support driven at a speed of 30 m / min, and dried by blowing dry air at 40°C onto the support until a self-supporting cast film (film-like material) was obtained. Then, the film was cooled to 10°C, and the cast film was peeled off from the support. Then, the peeled cast film was dried at 110°C for 30 minutes, and then stretched at 170°C in a direction (oblique direction) at 45° to the width direction at a stretching ratio of 2 times. As a result, an optical film 101 having a thickness of 40 μm and an in-plane slow axis in a direction of about 45° to the width direction was obtained. The optical film 101 had a retardation value Ro of 145 nm according to the above-mentioned method for evaluating retardation values, and was confirmed to function as a λ / 4 plate.

[0240] <Preparation of Optical Films 102 to 119> Optical films 102 to 119 were produced in the same manner as in the production of optical film 101, except that the example dye compounds were changed as shown in Table III.

[0241] Evaluation <Light transmittance> The light transmittance was measured using a spectrophotometer (U-3300 manufactured by Hitachi High-Tech Science) in accordance with JIS K 7375:2008 "Plastics - Determination of total light transmittance and total light reflectance". A light transmittance of 80% or more was marked as "Good", and a light transmittance of less than 80% was marked as "Poor".

[0242] <Light resistance test> The optical film thus prepared was subjected to a light resistance test. The film was irradiated with a xenon lamp (60 W / m 2 The absorbance of the thin film before irradiation (0 hour) and after irradiation (100 hours) was measured with a spectrophotometer, and the dye remaining rate was calculated according to the following formula (1). Formula (1) Dye residual rate (%)={(A 100 ) / (A0)}×100 (A0 is the absorbance before irradiation with the xenon lamp, A100 is the absorbance after irradiation with a xenon lamp.) The term "absorbance" refers to the absorbance at the maximum absorption wavelength of each compound, and the higher the dye remaining rate, the more difficult the compound is to decompose by light and the higher the light resistance. The light resistance was evaluated according to the following criteria.

[0243] A: Pigment remaining rate is 65% or more B: Pigment remaining rate is 40% or more but less than 65% C: Pigment remaining rate is 10% or more but less than 40% D: Pigment remaining rate is less than 10%

[0244] <Durability: Bleed-out evaluation> Each optical film was left for 1000 hours in a high-temperature and high-humidity atmosphere of 60° C. and 90% RH, and then the presence or absence of bleed-out (crystal precipitation) on the optical film surface was visually observed, and the bleed-out was evaluated according to the criteria described below.

[0245] ◎: No bleeding out was observed on the optical film surface. ○: Slight partial bleeding out is observed on the optical film surface. △: Slight bleeding out is observed over the entire surface of the optical film. ×: Clear bleeding out is observed over the entire surface of the optical film. The configurations of the optical films and the above evaluation results are shown in Table III.

[0246] [Table 3]

[0247] From the results in Table III, it is clear that the optical film of the present invention has excellent light transmittance, light resistance and durability by using a dye compound having a structure represented by general formula (1) according to the present invention.

[0248] Example 2 <Preparation of Optical Film 201> A coating composition was prepared by mixing 19.7 parts by mass of urethane acrylate (UA-1100H, manufactured by Shin-Nakamura Chemical Co., Ltd.), 0.1 parts by mass of photopolymerization initiator (Irgacure 184, manufactured by BASF), 0.3 parts by mass of modified silicone (KF-351A, manufactured by Shin-Etsu Chemical Co., Ltd.), 0.05 parts by mass of Emulgen 404 (manufactured by Kao Chemical Co., Ltd.), 39.5 parts by mass of propylene glycol monomethyl ether (PGME), 39.5 parts by mass of methyl acetate, and 0.1 parts by mass of exemplary dye compound 6 with sufficient stirring. The obtained coating composition was applied to a 25 μm thick COP substrate with a wire bar, and then dried and UV cured to produce an optical film 201 having a functional layer (hard coat layer) having a thickness of 5 μm.

[0249] <Preparation of Optical Films 202 to 212> Optical films 202 to 212 were produced in the same manner as in the production of optical film 201, except that the example dye compounds were changed as shown in Table IV. The light resistance and durability of the produced optical films 201 to 212 were evaluated in the same manner as in Example 1. The results are shown in Table IV.

[0250] [Table 4]

[0251] From the results in Table IV, it is clear that the optical film of the present invention has excellent light transmittance, light resistance and durability, similar to Example 1, by using a compound having a structure represented by general formula (1) according to the present invention in the functional layer.

[0252] Example 3 Using the optical films prepared in Examples 1 and 2, polarizing plates were prepared and evaluated.

[0253] <Preparation of Polarizing Plate 301> (1) Preparation of polarizer A long polyvinyl alcohol film with a thickness of 60 μm was continuously transported via guide rolls and immersed in a dye bath (30°C) containing iodine and potassium iodide for dyeing and stretching by 2.5 times. It was then stretched a total of 5 times and crosslinked in an acid bath (60°C) containing added boric acid and potassium iodide. The resulting iodine-PVA polarizer with a thickness of 12 μm was dried in a dryer at 50°C for 30 minutes to obtain a polarizer with a moisture content of 4.9%.

[0254] (2) Preparation of UV-curable adhesive The following components were mixed to obtain a liquid ultraviolet-curing adhesive (UV adhesive). 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate: 40 parts by mass Bisphenol A epoxy resin: 60 parts by mass Diphenyl[4-(phenylthio)phenyl]sulfonium hexafluoroantimonate (cationic polymerization initiator): 4 parts by mass

[0255] (3) Preparation of polarizing plates After the bonding surface of the optical film 101 was subjected to a corona treatment, the prepared ultraviolet curing adhesive was applied to a dry thickness of 3 μm using a coating device equipped with a chamber doctor. Similarly, the bonding surface of a Konica Minolta TAC KC4CT (thickness 40 μm, manufactured by Konica Minolta) serving as an opposing film was also subjected to a corona treatment, and the ultraviolet curing adhesive was applied to a dry thickness of 3 μm.

[0256] Immediately afterwards, the optical film 101 was laminated to one surface of the prepared polarizer, and the TAC film, which was the opposing film, was laminated to the other surface of the polarizer, using a roll-to-roll method, with an ultraviolet-curable adhesive between them. The lamination was performed so that the slow axis (or fast axis) of the optical film 101 and the absorption axis (or transmission axis) of the polarizer coincided (so that the angle between the in-plane slow axis of the optical film 101 and the absorption axis of the polarizer was 45°). Thereafter, the laminate was conveyed at a line speed of 20 m / min, and the accumulated light amount at wavelengths of 280 to 320 nm was 320 mJ / cm2. 2 UV rays were irradiated from the optical film 106 side by a metal halide lamp so that the UV-curable adhesive was cured to obtain polarizing plate 301. Note that, since polarizing plate 301 was produced by a roll-to-roll method, the long polarizing plate was finally cut along the width direction to obtain sheet-shaped polarizing plate 301.

[0257] The prepared polarizing plate 301 was attached to a portion of a commercially available organic EL image display device from which the polarizing plate on the viewing side had been peeled off, with the optical film 101 side of the polarizing plate facing the organic EL element, thereby preparing an organic EL image display device 301.

[0258] <Preparation of Polarizing Plates and Organic EL Image Display Devices 302 to 319> Polarizing plates 302 to 319 and organic EL image display devices 302 to 319 were produced in the same manner as in the production of polarizing plate 301, except that the optical film 101 was changed as shown in Table V. The polarizing plates 301 to 319 and the organic EL image display devices 301 to 319 thus produced were evaluated in the same manner as in Example 1 and were evaluated for light leakage as described below. The results are shown in Table V.

[0259] <Light leakage evaluation> The organic EL display device fabricated as described above was stored in an environment of 60°C and 90% RH for 500 hours, and then placed at room temperature and humidity (23°C and 55% RH) for 24 hours. The display was then visually inspected in a dark room for any light leakage from the screen during black display, and evaluated according to the following criteria. ○: No display unevenness due to light leakage △: Display unevenness due to light leakage is slightly observed ×: Display unevenness due to light leakage is evident

[0260] [Table 5]

[0261] It is apparent from Table V that by using the optical film of the present invention, a polarizing plate and an organic EL image display device having excellent light resistance and durability and free of light leakage can be obtained. [Industrial Applicability]

[0262] The optical film of the present invention has high transparency, prevents light leakage, and is excellent in light resistance and durability under severe environmental conditions, and therefore can be suitably used for polarizing plates and organic electroluminescence image displays. [Explanation of symbols]

[0263] 100 Polarizing Plate 101 Polarizer 102 Optical film 103 Opposing Film 104 Adhesive layer 200 Organic EL image display device 300 Organic EL element 301 Substrate 302 Metal electrode 303 Light-emitting layer 304 Transparent electrode 305 Sealing layer 400 adhesive layer

Claims

1. An optical film containing a thermoplastic resin, An optical film comprising a compound having a structure represented by the following general formula (1): 【Chemistry 1】 (In the formula, Z is any group represented by the following structural formula.) 【Chemistry 2】 (The symbol * indicates the bonding position of the double bond to the carbon atom. The group represented by the above structural formula may further have a substituent. Furthermore, R represents a substituent.)

2. 2. The optical film according to claim 1, wherein Z is any one of groups represented by the following structural formulas: 【Chemistry 3】 (The symbol * indicates the bonding position of the double bond to the carbon atom. The group represented by the above structural formula may further have a substituent. Furthermore, R represents a substituent.)

3. 3. The optical film according to claim 1, wherein the energy level of the highest occupied molecular orbital of the compound having the structure represented by the general formula (1) is −7.45 ev or more and −5.85 ev or less.

4. 4. The optical film according to claim 1, wherein the thermoplastic resin is a cyclic olefin resin or an acrylic resin.

5. The optical film according to claim 4 , wherein the cyclic olefin resin has a polar group.

6. The compound having a structure represented by the general formula (1) is contained in an amount of 0.01 to 20 mass% relative to the thermoplastic resin. The optical film according to any one of claims 1 to 5.

7. The optical film according to claim 1 , further comprising a functional layer.

8. 8. The optical film according to claim 7, wherein the functional layer contains a compound having a structure represented by the general formula (1).

9. 9. The optical film according to claim 1, which is a λ / 4 retardation film.

10. A polarizing plate comprising the optical film according to claim 1 .

11. 11. An organic electroluminescence image display device comprising: an optical film according to claim 1; or a polarizing plate according to claim 10.

Images