WO2021172179A1

WO2021172179A1 - Optical film, polarizing plate, and organic electroluminescence image display device

Info

Publication number: WO2021172179A1
Application number: PCT/JP2021/006251
Authority: WO
Inventors: 恵美子御子柴; 笠原　健三; 真紀子齊藤
Original assignee: コニカミノルタ株式会社
Priority date: 2020-02-28
Filing date: 2021-02-19
Publication date: 2021-09-02
Also published as: TWI845816B; KR20220097949A; CN115136045A; TW202147660A; JPWO2021172179A1

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

Optical film, polarizing plate and organic electroluminescence image display device

The present invention relates to an optical film, a polarizing plate, and an organic electroluminescence image display device. More specifically, when applied to an image display device, the present invention has high transparency, prevents light leakage, and is light resistant under harsher environmental conditions. The present invention relates to an optical film or the like having excellent properties and durability.

In an organic electroluminescence (hereinafter, also referred to as "organic EL") image display device, external light reflection by the metal plate inside the device is remarkable, and an antireflection film combining a λ / 4 retardation film and a polarizer is used. There is. When a cyclic olefin resin (hereinafter, also referred to as “COP”) is used as the material of the retardation film, reflection leakage occurs at a specific wavelength due to the influence of its wavelength dispersibility. 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 “specific wavelength light absorption layer”) in the display. The specific wavelength light absorption layer may be provided anywhere in the display, and may be provided as the λ / 4 retardation film.

However, when a dye is directly added to the resin to prepare a retardation film, there is an interaction with the resin, and photodegradation of the dye may be promoted.

For example, Patent Document 1 describes a method of adding a dye that absorbs light having a wavelength of about 400 nm to an adhesive layer in order to protect an organic EL element, and Patent Document 2 improves the brightness and visibility of an organic EL image display device. A method of adding a dye that selectively absorbs light in the vicinity of 470 nm and around 600 nm to the pressure-sensitive adhesive is disclosed.

In these techniques, a dye or a UV absorber is mainly added to the pressure-sensitive adhesive, but since the pressure-sensitive adhesive layer is thin, it is difficult to uniformly add the compound for expressing the function.

Further, Patent Document 3 describes that a plurality of dye compounds may be put into any layer of the functional layer in order to block ultraviolet rays from the outside and a part of visible light. Further, Patent Document 4 describes that an indole compound is contained in a thickener or the like, and Patent Document 5 describes that a dye compound having a specific structure having a cyano group and an ester group is added to a resin or a functional layer. However, there is a problem that all the dye compounds do not have sufficient light resistance.

Japanese Unexamined Patent Publication No. 2017-165941 Japanese Patent No. 5599740 JP-A-2017-198991 International Publication No. 2017/15996 Japanese Unexamined Patent Publication No. 2018-200463

The present invention has been made in view of the above problems and situations, and the problem to be solved is that when applied to an image display device, it has high transparency, prevents light leakage, and is light resistant under more severe environmental conditions. It is an object of the present invention to provide an optical film having excellent properties and durability, a polarizing plate provided with the optical film, and an organic electroluminescence image display device.

In order to solve the above problems, the present inventor is an optical film containing a thermoplastic resin in the process of examining the cause of the above problems, and by containing a compound having a specific structure, the image display device can be used. When applied, it has been found that an optical film having high transparency, preventing light leakage, and having excellent light resistance and durability under harsh environmental conditions can be obtained.

That is, the above problem according to the present invention is solved by the following means.

1. 1. An optical film containing a thermoplastic resin.
An optical film containing a compound having a structure represented by the following general formula (1).

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

2. The optical film according to item 1, wherein Z is any group represented by the following structural formula.

(The group represented by the above structural formula may further have a substituent. In addition, R represents a substituent.)

3. The optical film according to item 2, wherein Z is any group represented by the following structural formula.

4. Any one of the first to third terms, wherein the energy level of the highest occupied molecular orbital of the compound having the structure represented by the general formula (1) is −5.85 eV or less. The optical film described in.

5. The optical film according to any one of items 1 to 4, wherein the thermoplastic resin is a cyclic olefin resin or an acrylic resin.

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

7. Items 1 to 6 are characterized in that the compound having the structure represented by the general formula (1) is contained in the range of 0.01 to 20% by mass with respect to the thermoplastic resin. The optical film according to any one of the above.

8. The optical film according to any one of items 1 to 7, further comprising a functional layer.

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

10. The optical film according to any one of items 1 to 9, wherein the optical film is a λ / 4 retardation film.

11. A polarizing plate comprising the optical film according to any one of items 1 to 10.

12. An organic electroluminescence image display device comprising the optical film according to any one of items 1 to 10 or the polarizing plate according to item 11.

When applied to an image display device by the above means of the present invention, an optical film having high transparency, preventing light leakage, and having excellent light resistance and durability under harsh environmental conditions, and a polarizing plate provided with the optical film. And an organic electroluminescent image display device can be provided.

The mechanism of expression or mechanism of action of the effect of the present invention has not been clarified, but it is inferred as follows.

As the λ / 4 retardation film, a cyclic olefin resin film may be used from the viewpoints of low hygroscopicity and good dimensional stability.

However, since the cyclic olefin resin film exhibits flat wavelength dispersion characteristics, it is used as a λ / 4 retardation film for a circular polarizing plate in, for example, an organic electroluminescence (hereinafter, also referred to as “organic EL”) image display device. At that time, the reflected light tends to leak in a specific wavelength region (region on the short wavelength side). If the leakage of such reflected light is remarkable, the tint of the reflected light tends to be deteriorated.

In order to suppress the deterioration of color due to the reflected light as described above, the present inventors considered adding a dye compound that absorbs light in the wavelength region to the film. Since the organic EL image display device is used even in a high temperature and high humidity environment, it is required to suppress deterioration of the organic EL element due to external light. Further, since the dye compound is also deteriorated by the incident light, the light resistance of the compound itself is also required.

Therefore, in order to solve such a problem, if a dye compound having a specific structure is used, photodegradation can be suppressed, and further, when combined with a specific thermoplastic resin, λ / 4 with improved durability as a whole. We thought that a retardation film could be produced.

As a result of the examination, if the dye compound having the specific structure has a dicyano group, the cyano group can lower the energy level of the highest occupied molecular orbital (HOMO), that is, lower the oxidation potential, and thus suppress photooxidation. We have found that it can be done, and therefore has the effect of improving the light resistance of the dye compound. Then, they have found that if a resin type in which the energy level of the highest occupied molecular orbital (HOMO) of the dye compound and the energy level of the thermoplastic resin do not easily interact with each other is selected, deterioration of light resistance and durability can be further suppressed.

Sectional drawing which shows the structure of the polarizing plate 100 Disassembled sectional view of the organic EL image display device 200

The optical film of the present invention is an optical film containing a thermoplastic resin, and is characterized by containing 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.

In an embodiment of the present invention, from the viewpoint of exhibiting the effect of the present invention, Z in the structure represented by the general formula (1) is a group of either the structure represented by claim 2 or claim 3. Is preferable from the viewpoint of obtaining an optical film having an excellent balance between prevention of light leakage and light resistance.

Further, it is preferable that the energy level of the highest occupied molecular orbital 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.

Further, 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 having excellent light resistance and durability. Above all, when the cyclic olefin resin has a polar group, the energy level of the highest occupied orbital of the dye and the energy level of the resin are less likely to interact with each other, and deterioration of light resistance and durability can be suppressed.

In the present invention, it is preferable that the compound having the structure represented by the general formula (1) is contained in the range of 0.01 to 20% by mass with respect 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 from the film (also referred to as bleed-out) is likely to occur under high temperature and high humidity.

Further, it is preferable that the optical film has a functional layer, and it is preferable that the functional layer 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, a light scattering layer, and the like, but a hard coat layer is preferable from the viewpoint of imparting scratch resistance to the optical film.

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 a circular polarizing plate for antireflection.

Further, the organic electroluminescence image display device of the present invention is characterized by comprising the optical film or the polarizing plate of the present invention.

Hereinafter, the present invention, its constituent elements, and modes and modes for carrying out the present invention will be described in detail. In the present application, "-" is used to mean that the numerical values described before and after the value are included as the lower limit value and the upper limit value.

<< 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 by containing a compound having a structure represented by the following general formula (1).

According to the present invention, the energy level of the highest occupied molecular orbital (referred to as HOMO) can be lowered by using a compound having a structure represented by the general formula (1). By lowering the energy level of HOMO, the oxidation potential can be lowered and photooxidation can be suppressed. That is, it has the effect of improving the light resistance of the dye compound.

To calculate HOMO by calculating the molecular orbital of a compound having a structure represented by the general formula (1), use software for molecular orbital calculation using B3LYP as a general function and 6-31G (d) as a basis function as a calculation method. It can be calculated by using it, and the software is not particularly limited, and it can be calculated in the same manner by using any of them.

In the present invention, Gaussian 09 (Revision C.01, MJ Frisch, et al, Gaussian, Inc., 2010.) manufactured by Gaussian, USA is used as the software for calculating the molecular orbital.

Further, the optical film of the present invention is preferably transparent, and "transparent" means a spectrophotometer (for example, "Plastic-How to obtain total light transmittance and total light reflectance"" in accordance with JIS K 7375: 2008. It means that the light transmittance is 80% or more when measured using Hitachi High-Tech Science U-3300).

Hereinafter, the components of the present invention will be described in detail.

[1] Compound having a structure represented by the general formula (1) A compound having a structure represented by the general formula (1) according to the present invention (hereinafter, also referred to as “dye compound”) has the following structure.

Further, in the formula, Z is any group represented by the following structural formula, and may further have a substituent. In the following structural formula, R represents a substituent.

Above all, it is more preferable that Z is any group represented by the following structural formula from the viewpoint of exhibiting the effect of the present invention. In the following structural formula, R represents a substituent.

The above R represents a substituent, for example, a halogen atom (fluorine atom, chlorine atom, bromine atom, iodine atom, etc.), an alkyl group (methyl group, ethyl group, n-propyl group, isopropyl group, tert-butyl group, n). -Octyl group, 2-ethylhexyl group, etc.), cycloalkyl group (cyclohexyl group, cyclopentyl group, 4-n-dodecylcyclohexyl group, etc.), alkenyl group (vinyl group, allyl group, etc.), cycloalkenyl group (2-cyclopentene- 1-yl, 2-cyclohexene-1-yl group, etc.), alkynyl group (ethynyl group, propargyl group, etc.), aromatic hydrocarbon ring group (phenyl group, p-tolyl group, naphthyl group, etc.), aromatic heterocycle Group (2-pyrrole group, 2-furyl group, 2-thienyl group, pyrrol group, imidazolyl group, oxazolyl group, thiazolyl group, benzoimidazolyl 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, isooxazole group, 1,2,4-oxadiazol group, 1 , 3,4-oxadiazol group, thiazole group, isothiazole group, 1,2,4-thiodiazol group, 1,3,4-thiadiazol 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, benzoyl) Amino group, etc.), alkyl and arylsulfonylamino groups (methylsulfonylamino group, butylsulfonylamino group, phenylsulfonylamino group, 2,3,5-trichlorophenylsulfonylamino group, p-methylphenylsulfonylamino) Groups, etc.), mercapto groups, alkylthio groups (methylthio group, ethylthio group, n-hexadecylthio group, etc.), arylthio groups (phenylthio group, p-chlorophenylthio group, m-methoxyphenylthio group, etc.), sulfamoyl group (N-ethyl) Sulfamoyl group, N- (3-dodecyloxypropyl) sulfamoyl group, N, N-dimethylsulfamoyl group, N-acetylsulfamoyl group, N-benzoyl sulfamoyl group, N- (N'-phenyl) Carbamoyl) 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- Examples thereof include n-octylcarbamoyl group, N- (methylsulfonyl) carbamoyl group, etc.).

Hereinafter, a dye compound having a structure represented by the general formula (1) according to the present invention will be exemplified, but the present invention is not limited thereto.

The molecular weight of the dye compound is not particularly limited, but it is preferably not too large, for example, preferably 100 to 1000, in order to facilitate intermolecular penetration of the cyclic olefin resin or acrylic resin. The molecular weight of the dye compound can be calculated from the formula amount of the chemical structural formula by specifying the chemical structure by, for example, an NMR (Nuclear Magnetic Resonance) apparatus or the like.

The maximum absorption wavelength of the dye compound is preferably in the range of 370 to 460 nm, and 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 easily absorbs light in the wavelength region appropriately. Therefore, for example, the optical film is used as a λ / 4 retardation film in an organic EL image display device. If so, the 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 an ultraviolet visible spectrophotometer UV-2450 manufactured by Shimadzu Corporation.

The dye compound may be obtained synthetically or a commercially available product may be used. For example, the synthesis of the exemplary dye compound 12 can be synthesized by the following scheme.

Weighed 1.5 g of compound (12-1) and 0.697 g of malononitrile in 100 mL of 3-headed corben, and added 40 mL of toluene to dissolve it. Next, 0.817 g of morpholine was added dropwise, the temperature was raised, and the mixture was heated under reflux for 4 hours. After completion of the reaction, the solvent was removed under reduced pressure, 10 mL of methanol was added, and the mixture was stirred in a suspended state. The precipitate was filtered and dried to obtain 1.89 g (yield 96%) of the powder of Exemplified Dye Compound 12. The structure was confirmed by NMR.

The content of the dye compound is preferably in the range of 0.01 to 20% by mass with respect to the cyclic olefin resin. When the content of the dye compound is 0.01% by mass or more, light in a specific wavelength region is appropriately absorbed to improve light resistance while suppressing leakage of reflected light in, for example, an organic EL image display device. The effect of When the content of the dye compound is 20% by mass or less, not only can bleed-out be less likely to occur, but also the absorption of light in a specific wavelength region of the optical film does not increase too much, so that a decrease in brightness can be suppressed. From the same viewpoint, the content of the dye compound is more preferably in the range of 0.015 to 10% by mass with respect to the cyclic olefin resin.

[2] Thermoplastic Resin The thermoplastic resin material according to the present invention is not limited as long as it can be treated as a film after film formation. For example, examples of the thermoplastic resin used for polarizing plates include cellulose ester resins such as triacetyl cellulose (TAC), cellulose acetate propionate (CAP), and diacetyl cellulose (DAC), and cycloolefin polymers (hereinafter referred to as cycloolefin polymers). Cyclic olefin resins such as COP and cycloolefin resins), polypropylene resins such as polypropylene (PP), acrylic resins such as polymethylmethacrylate (PMMA), and polyesters such as polyethylene terephthalate (PET). Cellulose acetate can be applied.

Among them, cyclic olefin resins and acrylic resins are preferable from the viewpoint of optical properties including phase difference and physical properties such as durability.

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

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

In the general formula (A-1), R ¹ to R ⁴ independently represent a hydrogen atom, a hydrocarbon group having 1 to 30 carbon atoms, or a polar group. p represents an integer of 0 to 2. However, ^{all of R 1} to R ⁴ do not represent hydrogen atoms at the same time, R ¹ and R ² do not represent hydrogen atoms at the same time, and R ³ and R ⁴ do not represent hydrogen atoms at the same time. do.

^{The hydrocarbon group having 1 to 30 carbon atoms represented by R 1} to R ⁴ in the general formula (A-1) is preferably, for example, a hydrocarbon group having 1 to 10 carbon atoms, and is preferably a carbon atom. More preferably, it is a hydrocarbon group having a number of 1 to 5. 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 carbonyl groups, imino groups, ether bonds, silyl ether bonds, thioether bonds and the like. Examples of the hydrocarbon group having 1 to 30 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group and the like.

^{Examples of the polar groups represented by R 1} to R ⁴ in the general formula (A-1) 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. Is included. Of these, a carboxy group, a hydroxy group, an alkoxycarbonyl group and an aryloxycarbonyl group are preferable, and an alkoxycarbonyl group and an aryloxycarbonyl group are preferable from the viewpoint of ensuring solubility during solution film formation.

P in the general formula (A-1) is preferably 1 or 2 from the viewpoint of increasing the heat resistance of the optical film. This is because when p is 1 or 2, the obtained polymer becomes bulky and the glass transition temperature tends to be improved.

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

^{R 5} in the general formula (A-2) preferably represents a hydrocarbon group having 1 to 5 carbon atoms, and more preferably represents a hydrocarbon group having 1 to 3 carbon atoms.

^{R 6} in the general formula (A-2) preferably represents a carboxy group, a hydroxy group, an alkoxycarbonyl group and an aryloxycarbonyl group, and from the viewpoint of ensuring solubility during solution film formation, the alkoxycarbonyl group and aryl Oxycarbonyl groups are more preferred.

P in the general formula (A-2) preferably represents 1 or 2 from the viewpoint of enhancing the heat resistance of the optical film. This is because when p represents 1 or 2, the obtained polymer becomes bulky and the glass transition temperature tends to improve.

A cycloolefin monomer having a structure represented by the general formula (A-2) is preferable from the viewpoint of improving the solubility in an organic solvent. In general, an organic compound loses its symmetry and thus its crystallinity is lowered, so that its solubility in an organic solvent is improved. ^{Since R 5} and R ⁶ in the general formula (A-2) are substituted with only the ring-constituting carbon atom on one side with respect to the axis of symmetry of the molecule, the symmetry of the molecule is low, that is, the general formula (A-). Since the cycloolefin monomer having the structure represented by 2) has high solubility, it is suitable for producing an optical film by a solution casting method.

The content ratio of the cycloolefin monomer having the structure represented by the general formula (A-2) in the polymer of the cycloolefin monomer is the total of all the cycloolefin monomers constituting the cycloolefin resin. For example, it can be 70 mol% or more, preferably 80 mol% or more, and more preferably 100 mol%. When a cycloolefin monomer having a structure represented by the general formula (A-2) is contained in a certain amount or more, the orientation of the resin is increased, so that the retardation value is likely to increase.

Hereinafter, specific examples of the cycloolefin monomer having the structure represented by the general formula (A-1) are shown in Examples Compounds 1 to 14, and the cycloolefin single having the structure represented by the general formula (A-2) is shown. Specific examples of the merits are shown in Exemplified Compounds 15 to 34.

Examples of copolymerizable monomers copolymerizable with cycloolefin monomers include copolymerizable monomers capable of ring-opening copolymerization with cycloolefin monomers and addition copolymerization with cycloolefin monomers. Possible copolymerizable monomers and the like are included.

Examples of ring-opening copolymerizable copolymerizable monomers include cycloolefins such as cyclobutene, cyclopentene, cycloheptene, cyclooctene and dicyclopentadiene.

Examples of copolymerizable monomers that can be added and copolymerized include unsaturated double bond-containing compounds, vinyl-based cyclic hydrocarbon monomers, and (meth) acrylates. Examples of unsaturated double bond-containing compounds include olefin compounds having 2 to 12 (preferably 2 to 8) carbon atoms, and examples thereof include ethylene, propylene and butene. Examples of vinyl-based cyclic hydrocarbon monomers include vinyl cyclopentene-based 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.

The content ratio of the cycloolefin monomer in the copolymer of the cycloolefin monomer and the copolymerizable monomer is, for example, 20 to 80 mol% with respect to the total of all the monomers constituting the copolymer. It can be preferably 30 to 70 mol%.

As described above, the cycloolefin-based resin is obtained by polymerizing a cycloolefin monomer having a norbornene skeleton, preferably a cycloolefin monomer having a structure represented by the general formula (A-1) or (A-2). It is a polymer obtained by copolymerization, and examples thereof include the following.

(1) Ring-opening polymer of cycloolefin monomer (2) Ring-opening copolymer of cycloolefin monomer and copolymerizable copolymer with ring-opening copolymerization (3) The above (1) Alternatively, a hydrogenated product of the ring-opened (co) polymer of (2) (4) The ring-opened (co) polymer of (1) or (2) above was cyclized by the Friedercrafts reaction and then hydrogenated ( Co) Polymer (5) Saturated copolymer of cycloolefin monomer and unsaturated double bond-containing compound (6) Addition copolymer of vinyl-based cyclic hydrocarbon monomer of cycloolefin monomer (7) Alternating copolymer of cycloolefin monomer and (meth) acrylate The polymers of (1) to (7) above are all known methods, for example, Japanese Patent Application Laid-Open No. 2008-. It can be obtained by the method described in Japanese Patent Application Laid-Open No. 107534 and Japanese Patent Application Laid-Open No. 2005-227606. For example, as the catalyst and solvent used for the ring-opening copolymerization of (2) above, those described in paragraphs 0019 to 0024 of JP-A-2008-107534 can be used, for example. As the catalyst used for hydrogenation of (3) and (6) above, for example, those described in paragraphs 0025 to 0028 of JP-A-2008-107534 can be used. As the acidic compound used in the Friedel-Crafts reaction of (4) above, for example, those described in paragraph 0029 of JP-A-2008-107534 can be used. As the catalyst used for the addition polymerization of the above (5) to (7), for example, those described in paragraphs 0058 to 0063 of JP-A-2005-227606 can be used. The alternating copolymerization reaction of (7) above can be carried out, for example, by the method described in paragraphs 0071 and 0072 of JP-A-2005-227606.

Among them, the polymers of the above (1) to (3) and (5) are preferable, and the polymers of the above (3) and (5) are more preferable. That is, the cycloolefin-based resin has a structural unit represented by the following general formula (B-1) in that the glass transition temperature of the obtained cycloolefin-based resin can be increased and the light transmittance can be increased. It is preferable that at least one of the structural units represented by the following general formula (B-2) is contained, and only the structural unit represented by the general formula (B-2) is included, or the general formula (B-1) is used. It is more preferable to include both the structural unit represented 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 is represented by the general formula (B-2). The structural unit is a structural unit derived from the cycloolefin monomer represented by the above-mentioned general formula (A-2).

In the general formula (B-1), X represents -CH = CH- or -CH ₂ CH _2- . R ¹ ~ R ⁴ and p are respectively the same as R ¹ ~ R ⁴ and p of the general formula (A-1).

In the general formula (B-2), X represents -CH = CH- or -CH ₂ CH _2- . R ⁵ ~ R ⁶ and p are respectively the same as R ⁵ ~ R ⁶ and p in the general formula (A-2).

The cycloolefin resin according to the present invention may be a commercially available product. Examples of commercially available cycloolefin resins include Arton G (eg, G7810, etc.), Arton F, Arton R (eg, R4500, R4900, R5000, etc.) and Arton RX manufactured by JSR Corporation. included.

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

The number average molecular weight (Mn) of the cycloolefin resin is preferably in the range of 8000 to 100,000, more preferably in the range of 10,000 to 80,000, and further preferably in the range of 12,000 to 50,000. The weight average molecular weight (Mw) of the cycloolefin resin is preferably in the range of 20000 to 300,000, more preferably in the range of 30,000 to 250,000, and even more preferably in the range of 40,000 to 200,000. The number average molecular weight and the weight average molecular weight of the cycloolefin resin can be measured by gel permeation chromatography (GPC) in terms of polystyrene.

<Gel Permeation Chromatography>
Solvent: Methylene chloride Column: Shodex K806, K805, K803G (Three made by Showa Denko KK were connected and used)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (manufactured by GL Science)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0 mL / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corporation) A calibration curve with 13 samples in the range of Mw = 500 to 2800000 was used. The 13 samples are preferably used at approximately equal intervals.

When the intrinsic viscosity [η] inh, the number average molecular weight and the weight average molecular weight are within the above ranges, the heat resistance, water resistance, chemical resistance, mechanical properties, and molding processability as a film of the cycloolefin resin are good. Become.

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 120 to 220 ° C. It is more preferable that the range is. When Tg is 110 ° C. or higher, deformation under high temperature conditions can be easily suppressed. On the other hand, when the Tg is 350 ° C. or lower, the molding process becomes easy, and the deterioration of the resin due to the heat during the molding process is also easily suppressed.

The content of the cycloolefin resin is preferably 70% by mass or more, more preferably 80% by mass or more with respect to the film.

[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 a copolymer with another monomer.

Therefore, the acrylic resin according to the present invention also includes a methacrylic resin. The resin is not particularly limited, but the methyl methacrylate unit is in the range of 50 to 99% by mass, and other monomer units copolymerizable therewith are in the range of 1 to 50% by mass. Is preferable.

Other units constituting the acrylic resin formed by copolymerization include alkylmethacrylate having an alkyl number of 2 to 18, alkylacrylate having an alkyl number of 1 to 18, isobornyl methacrylate, and 2-. Hydroxyalkyl acrylates such as hydroxyethyl acrylates, α, β-unsaturated acids such as acrylic acid and methacrylic acid, acrylamides such as acryloylmorpholin and N-hydroxyphenylmethacrylate, N-vinylpyrrolidone, maleic anhydride, fumaric acid and itaconic acid. Unsaturated group-containing divalent carboxylic acids such as, styrene, aromatic vinyl compounds such as α-methylstyrene, α, β-unsaturated nitriles such as acryloyl nitrile and methacrylic nitrile, maleic anhydride, maleimide, N-substituted maleimide, etc. Glutalimide, glutaric anhydride and the like can be mentioned.

Examples of the copolymerizable monomer forming a unit excluding glutarimide and glutaric anhydride from the above unit include a monomer corresponding to the above unit. That is, alkyl methacrylate having an alkyl number of 2 to 18 carbons, alkyl acrylate having an alkyl number of 1 to 18 carbon atoms, hydroxyalkyl acrylate such as isobornyl methacrylate and 2-hydroxyethyl acrylate, acrylic acid, methacrylic acid and the like. Unsaturated group-containing divalent carboxylic acids such as α, β-unsaturated acid, acrylic morpholine, acrylamide such as N-hydroxyphenylmethacrylic acid, N-vinylpyrrolidone, maleic acid, fumaric acid, and itaconic acid, styrene, α-methylstyrene. Examples thereof include aromatic vinyl compounds such as, acrylonitrile, α, β-unsaturated nitriles such as methacrylic acid, maleic anhydride, maleimide, N-substituted maleimide, and the like.

Further, 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 imidize it (see JP-A-2011-26563). .).

The glutaric anhydride unit can be formed, for example, by heating an intermediate polymer having a (meth) acrylic acid ester unit (see Japanese Patent No. 4961164).

Among the above-mentioned structural units, the acrylic resin according to the present invention contains isobornyl methacrylate, acryloylmorpholine, N-hydroxyphenylmethacrylamide, N-vinylpyrrolidone, styrene, hydroxyethyl methacrylate, and anhydride from the viewpoint of mechanical strength. It is particularly preferred that maleic acid, maleimide, N-substituted maleimide, glutaric anhydride or glutarimide are included.

The acrylic resin according to the present invention has the viewpoint of controlling dimensional changes with respect to changes in the temperature and humidity atmosphere of the environment, peelability from a metal support during film production, drying properties of an organic solvent, heat resistance, and mechanical strength. From the viewpoint of improvement, the weight average molecular weight (Mw) is preferably in the range of 50,000 to 1,000,000, more preferably in the range of 100,000 to 1,000,000, and in the range of 200,000 to 800,000. It is particularly preferable to have.

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

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

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

As the acrylic resin according to the present invention, a commercially available one can also be used. For example, Delpet 60N, 80N, 980N, SR8200 (all manufactured by Asahi Kasei Chemicals Co., Ltd.), Dianar BR52, BR80, BR83, BR85, BR88, EMB-143, EMB-159, EMB-160, EMB-161, Examples thereof include 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.) and the like. Two or more kinds of acrylic resins can be used in combination.

The acrylic resin according to the present invention preferably contains an additive, and as an example of the additive, the acrylic particles (rubber elastic particles) described in International Publication No. 2010/001668 are used as the mechanical strength of the film. It is preferably contained for improvement and adjustment of the dimensional change rate. Examples of commercially available products of such a multilayer structure acrylic granular composite include "Metabrene W-341" manufactured by Mitsubishi Rayon, "Kaneka" manufactured by Kaneka, "Paraloid" manufactured by Kureha, and Roamand. Examples include "Acryloid" manufactured by Haas, "Stafyroid" manufactured by Aika, Chemisnow MR-2G, MS-300X (above, manufactured by Soken Kagaku Co., Ltd.) and "Parapet SA" manufactured by Kuraray. Can be used alone or in combination of two or more.

The volume average particle diameter 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. When the particle size is above a certain level, the film can be easily stretched under heating, and when the particle size is below a certain level, the transparency of the obtained film is not easily impaired.

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, still more preferably 1.2 GPa or less. This flexural modulus varies depending on the type and amount of acrylic resin and rubber elastic particles in the film. For example, the larger the content of rubber elastic particles, the smaller the flexural modulus. Further, as the acrylic resin, the flexural modulus is generally smaller when a copolymer of alkyl methacrylate and alkyl acrylate or the like is used than when a homopolymer of alkyl methacrylate is used.

[3] Other Components The optical film of the present invention may further contain components other than the above as long as the effects of the present invention are not impaired. Examples of other components include matting agents, UV absorbers, phase difference adjusters (phase difference increasing agents, phase difference reducing agents), plasticizers, antioxidants, light stabilizers, antistatic agents, release agents, and boosters. Contains thickeners. Above all, 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.

(Matte agent)
The matting agent is fine particles. The fine particles may be inorganic fine particles or resin fine particles. Examples of inorganic fine particles include 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 fine particles of inorganic compounds such as calcium phosphate. Among them, the inorganic fine particles are preferably silicon dioxide fine particles from the viewpoint that it is difficult to increase the haze of the optical film and the friction coefficient can be effectively lowered.

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

Examples of resin fine particles include fine particles such as silicone resin, fluororesin, and acrylic resin. Of these, silicone resin fine particles are preferable, and resin fine particles having a three-dimensional network structure are particularly preferable. Examples of the resin fine particles include Tospearl 103, 105, 108, 120, 145, 3120 and 240 (all manufactured by Toshiba Silicone Co., Ltd.).

The average particle size of the primary particles of the fine particles is preferably in the range of 0.005 to 0.4 μm, 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.

The content of the fine particles is preferably in the range of 0.01 to 3.0% by mass, more preferably in the range of 0.01 to 2.0% by mass with respect to the optical film. The coefficient of dynamic friction on the surface of the optical film is preferably in the range of 0.2 to 1.0.

[4] Manufacturing method of optical film [4.1] Physical characteristics of optical film (phase difference Ro)
From the viewpoint of using the optical film as, for example, a λ / 4 retardation film, the in-plane retardation Ro measured in an environment with a measurement wavelength of 550 nm and 23 ° C. and 55% RH is in the range of 100 to 170 nm. Is preferable, and the range is more preferably in the range of 130 to 150 nm.

Ro is defined by the following formula.

Equation (1): Ro = (n _{x −} n _y ) × d
(In the equation (1), n _x represents the refractive index in the in-plane slow-phase axis direction (the direction in which the refractive index becomes maximum) of _{the film, and n y} is the direction orthogonal to the in-plane slow-phase axis of the film. It represents the refractive index, and d represents the thickness (nm) of the film.)
The in-plane slow-phase axis of the optical film can be confirmed by an automatic birefringence meter Axoscan (Axo Scan Mueller Matrix Polarimeter: manufactured by Axometrics). 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 °. Is.

Ro can be measured by the following method.

1) The optical film is humidity-controlled 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.

2) The retardation Ro of the film after humidity control at a measurement wavelength of 550 nm was measured in an environment of 23 ° C. and 55% RH using an automatic birefringence meter Axoscan (AxoScan Mueller Matrix Polarimeter: manufactured by Axometrics). taking measurement.

The phase difference Ro of the optical film can be adjusted, for example, by the monomer composition of the cycloolefin resin and the stretching conditions.

(Amount of residual solvent)
Since the optical film is preferably formed by a solution casting method, it may further contain a residual solvent. The amount of residual solvent is preferably 700 ppm or less, more preferably 30 to 700 ppm with respect 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 process of manufacturing the optical film.

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 gas in the container is promptly injected into a gas chromatograph with the container filled with volatile components, and mass spectrometry is performed to identify the compound. The volatile components are quantified while doing so. In the headspace method, it is possible to observe all peaks of volatile components by gas chromatography, and by using an analysis method that utilizes electromagnetic interaction, volatile substances and monomers can be detected with high accuracy. Quantification can also be performed.

(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.

[4.2] Method for Producing Optical Film The optical film of the present invention comprises 1) a step of preparing a dope containing the cycloolefin resin or acrylic resin, the dye compound, and a solvent, and 2) the obtained dope. It can be produced through a step of casting on a support and then drying and peeling to obtain a cast film, and 3) a step of stretching the obtained cast film. Further, the optical film of the present invention further comprises 4) a step of drying the stretched cast film, 5) a step of cutting both ends of the obtained optical film and embossing the film, and 6) a winding step. It may be manufactured through.

About step 1) (dope preparation step) Cycloolefin resin or acrylic resin and dye compound are dissolved or dispersed in a solvent to prepare a dope.

The solvent used for doping contains at least an organic solvent (good solvent) capable of dissolving a cycloolefin resin. Examples of good solvents include chlorine-based organic solvents such as methylene chloride; non-chlorine-based organic solvents such as methyl acetate, ethyl acetate, acetone and tetrahydrofuran. Of these, methylene chloride is preferable.

The solvent used for doping may further contain a poor solvent. Examples of poor solvents include straight-chain or branched-chain aliphatic alcohols having 1 to 4 carbon atoms. When the ratio of alcohol in the dope is high, the film-like substance tends to gel and peels off from the metal support easily. Examples of the linear or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Of these, ethanol is preferable because of its dope stability, relatively low boiling point, and good drying property.

The dope obtained in the step 2) (casting step) is cast on the support. Dope casting can be performed by discharging from a casting die.

The solvent is evaporated until the dope cast on the support can be peeled off from the support by a peeling roll. Examples of the method of evaporating the solvent include a method of blowing wind on the cast dope, a method of transferring heat from the back surface of the support with a liquid, and a method of transferring heat from the front and back surfaces with radiant heat.

After that, the cast film obtained by evaporating the solvent is peeled off with a peeling roll.

The amount of residual solvent in the cast film on the support at the time of peeling may be in the range of 50 to 120% by mass, for example, depending on the drying conditions and the length of the support. If peeling is performed with a large amount of residual solvent, the cast film is too soft and the flatness during peeling tends to be impaired, and wrinkles and vertical streaks due to peeling tension are likely to occur. The amount of residual solvent is determined. The amount of residual solvent is defined by the following formula.

Residual solvent amount (mass%) = (mass before heat treatment of casting film-mass after heat treatment of casting film) / (mass after heat treatment of casting film) × 100
The heat treatment for measuring the amount of residual solvent is a heat treatment at 115 ° C. for 1 hour.

About step 3) (stretching step) The casting film obtained by peeling from the support is stretched.

Stretching may be performed according to the required optical characteristics, and it is preferable to stretch in one or more of the width direction (TD direction), the transport 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 it in an oblique direction.

The draw ratio depends on the required optical characteristics, but when used as a λ / 4 retardation film, it is preferably in the range of 1.05 to 4.0 times, preferably 1.5 to 3.0 times. More preferably, it is in the range.

The stretch ratio (times) is defined as the stretch direction size of the film after stretching / the stretch direction size of the film before stretching. When biaxial stretching is performed, it is preferable to set the stretching ratio in each of the TD direction and the MD direction.

The stretching temperature (drying temperature during stretching) is preferably in the range of (Tg + 2) to (Tg + 50) ° C., preferably in the range of (Tg + 2) to (Tg + 50) ° C., where Tg is the glass transition temperature of the cycloolefin resin, as described above. It is more preferably in the range of (Tg + 30) ° C. When the stretching temperature is (Tg + 2) ° C. or higher, the solvent is easily volatilized appropriately, so that the stretching tension can be easily adjusted to an appropriate range. The sex is not easily impaired. As the stretching temperature, it is preferable to measure the atmospheric temperature such as (a) the temperature inside the stretching machine in the same manner as described above.

The amount of residual solvent in the film-like material at the start of stretching is preferably about the same as the amount of residual solvent in the film-like material at the time of peeling, and is preferably in the range of, for example, 20 to 30% by mass, 25. More preferably, it is in the range of about 30% by mass.

Stretching of the film-like object in the TD direction (width direction) can be performed, for example, by fixing both ends of the film-like object with clips or pins and widening the distance between the clips or pins in the traveling direction (tenter method). Stretching of the film-like material in the MD direction can be performed, for example, by a method (roll method) in which a plurality of rolls are provided with a peripheral speed difference and the roll peripheral speed difference is utilized between the rolls. In particular, a tenter method in which both ends of the casting film are gripped by a clip or the like and stretched is preferable in order to improve the flatness and dimensional stability of the film. By stretching the flow film in both the MD direction and the TD direction, it is preferable to stretch (diagonally stretch) in a direction that diagonally intersects the MD direction and the TD direction.

About step 4) (drying step) The stretched casting film is further dried to obtain an optical film.

Drying of the cast film can be performed, for example, while transporting the cast film by a plurality of transport rolls (for example, a plurality of transport rolls arranged in a staggered pattern when viewed from the side surface). The drying means is not particularly limited, and hot air, infrared rays, heating rolls or microwaves are used. Hot air drying is preferable from the viewpoint of simplicity.

About step 5) (cutting / embossing step) Both ends of the obtained optical film in the width direction are cut. Both ends of the optical film can be cut by a slitter.

Next, embossing (knurling) is performed on both ends of the optical film in the width direction. The embossing process 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. By such embossing, winding misalignment and blocking (sticking between films) in the next winding process can be suppressed as much as possible.

About the step (winding step) of 6) Then, the obtained optical film is wound up to obtain a roll body.

That is, the optical film is wound around the winding core while being conveyed to form a roll body. The method of winding the optical film may be any method using a winder that is generally used, and is a method of controlling tension such as a constant torque method, a constant tension method, a taper tension method, and a program tension control method with a constant internal stress. There is.

The winding length of the optical film in the roll body is preferably in the range of 1000 to 7200 m. The width of the optical film is preferably in the range of 1000 to 3000 mm.

[5] Other Functional Layers The optical film of the present invention preferably has a functional layer, and the functional layer may contain a compound having a structure represented by the general formula (1). preferable. 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, a barrier layer, etc., but when incorporated into an organic EL image display device, scratch resistance It is preferable to provide a hard coat layer in order to improve the above.

[5.1] Hard Coat Layer The hard coat layer used in the present invention is preferably contained with an active ray-curable resin because it is excellent in mechanical film strength (scratch resistance, pencil hardness). That is, it is a layer containing a resin as a main component, which is cured through a cross-linking reaction by irradiation with active rays (also referred to as active energy rays) such as ultraviolet rays and electron beams. As the active ray-curable resin, a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and the active ray-curable resin layer is formed by curing by irradiating with an active ray such as ultraviolet rays or an electron beam. NS. Typical examples of the active ray-curable resin include an ultraviolet curable resin and an electron beam curable resin, and the resin cured by ultraviolet irradiation is particularly excellent in mechanical film strength (scratch resistance, pencil hardness). It is preferable from the point of view. Examples of the ultraviolet curable resin include an ultraviolet curable acrylate resin, an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, and an ultraviolet ray. A curable epoxy resin or the like is preferably used, and among them, an ultraviolet curable acrylate resin is preferable.

Commercially available products include Adekaoptomer N series, Sunrad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612 (all manufactured by Sanyo Kasei Kogyo Co., Ltd.). , Aronix M-6100, M-8030, M-8060, Aronix M-215, Aronix M-315, Aronix M-313, Aronix M-327 (all manufactured by Toa Synthetic 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 (above, Shin-Nakamura Chemical Industry Co., Ltd.) (Manufactured by), PE-3A (manufactured by Kyoeisha Chemical Co., Ltd.) and the like. The above-mentioned active ray-curable resin may be used alone or in combination of two or more.

Further, it is preferable that the hard coat layer contains a photopolymerization initiator in order to accelerate the curing of the active ray-curable resin. The amount of the photopolymerization initiator is preferably contained in the range of photopolymerization initiator: active ray-curable resin = 20: 100 to 0.01: 100 in terms of mass ratio. Specific examples of the photopolymerization initiator include alkylphenone-based, acetophenone, benzophenone, hydroxybenzophenone, Michler ketone, α-amyloxime ester, thioxanthone and the like, and derivatives thereof. It is not particularly limited to these.

Commercially available products may be used as such a photopolymerization initiator, and examples thereof include Irgacure 184, Irgacure 907, and Irgacure 651 manufactured by BASF Japan Ltd. as preferable examples.

The thickness of the hard coat layer is preferably in the range of 0.1 to 50 μm, preferably in the range of 1 to 20 μm, from the viewpoint of improving the hard coat property and improving the transparency of the optical film. More preferred.
The method for forming the hard coat layer is not particularly limited. For example, after preparing a coating liquid for forming a hard coat layer containing each of the above components, the coating liquid is applied with a wire bar or the like, and the coating liquid is cured by heat or ultraviolet rays. , A method of forming a hard coat layer and the like.
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 from the viewpoint of further improving light resistance and imparting scratch resistance. It is preferably contained in the range of 0.1 to 40% by mass, more preferably in the range of 0.1 to 20% by mass, based on the ultraviolet curable resin.

[6] Polarizing Plate The polarizing plate of the present invention has a polarizing element and an optical film of the present invention arranged on at least one surface thereof.

FIG. 1 is a cross-sectional view showing the configuration of the polarizing plate 100.
As shown in FIG. 1, the polarizing plate 100 of the present invention comprises a polarizing element 101, an optical film 102 of the present invention arranged on one surface thereof, an opposing film 103 arranged on the other surface, and polarized light. It may have two adhesive layers 104 arranged between the child 101 and the optical film 102 and between the polarizer 101 and the opposing film 103.

(About Polarizer 101)
The polarizer 101 is an element that allows only light on a plane of polarization in a certain direction to pass through, and is a polyvinyl alcohol-based stretched film doped with iodine or a dichroic dye.

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.

(About optical film 102)
The optical film 102 can function as a retardation film, for example, a λ / 4 retardation film used for a circularly polarizing plate of an organic EL image display device.

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

The optical film 102 may further have other layers (for example, a hard coat layer, a low refractive index layer, and an antireflection layer) arranged on the surface opposite to the polarizer 101, depending on the application. , The optical film 102 may further have an easy-adhesion layer (not shown) arranged on the surface on the side of the polarizer 101.

(About the opposing film 103)
The opposing film 103 may be the optical film of the present invention or another optical film (that is, a protective film). More preferably, the optical film of the present invention is used and the hard coat layer is provided on the outermost surface.

Examples of commercially available protective films include commercially available cellulose ester films (eg, Konica Minolta Tuck KC8UX, KC5UX, KC4UX, KC8UCR3, KC4SR, KC4BR, KC4CR, KC4DR, KC4FR, KC4KR, KC8UY, KC6UY, KCUEK, KC6UY, KC4UY KC8UY-HA, KC2UA, KC4UA, KC6UA, KC8UA, KC2UAH, KC4UAH, KC6UAH, manufactured by Konica Minolta Co., Ltd. The above includes Fuji Film Co., Ltd.).

As a commercially available cycloolefin-based film, various grades of cycloolefin polymer (COP) molded product-Zeonor film (R) manufactured by Zeon Corporation are preferably used.

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

(About the adhesive layer 104)
The adhesive layer 104 may be arranged between the polarizer 101 and the optical film 102, and between the polarizer 101 and the opposing film 103, respectively.

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

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

The polarizing plate 100 may have a long shape or a sheet shape obtained by cutting a long polarizing plate along the width direction.

(Physical characteristics)
(T ₁ / T ₂ )
When an aluminum reflective material is laminated on the optical film of the polarizing plate via an adhesive layer, the reflectance of light having a wavelength of 460 nm of the polarizing plate is T ₁ (%), and the reflectance of light having a wavelength of 650 nm is T ₂ When (%), the polarizing plate preferably satisfies the following formula (2).

Equation (2): 0 <T ₁ / T ₂ <2.6
When T ₁ / T ₂ is less than 2.6, the reflectance of light having a wavelength of 460 nm is not too high, that is, leakage of reflected light in the vicinity of the wavelength can be suppressed. Therefore, for example, reflection in an organic EL image display device. The color of light can be improved. Further, when T ₁ / T ₂ is more than 0, for example, the light emission in the wavelength region in the organic EL image display device is not easily obstructed by the dye compound, so that the decrease in brightness can be suppressed. More preferably, T ₁ / T ₂ is 2.5 or less.

(Color difference ΔE (a ^* b ^* ))
Further, the color difference ΔE (a ^* b ^* ) of the polarizing plate is preferably less than 25, more preferably less than 20. When the color difference ΔE (a * b *) of the polarizing plate is within the above range, for example, the tint of the reflected light in the organic EL image display device can be improved.

The T ₁ / T _{2 of the} polarizing plate and the color difference ΔE (a ^* b ^* ) can be measured by the following procedure.

1) An aluminum reflective material is laminated on the optical film of the polarizing plate via an adhesive layer to prepare a polarizing plate sample. The pressure-sensitive adhesive is an acrylic pressure-sensitive adhesive.

2) The spectral reflectance and color difference ΔE (a ^* b ^* ) of the obtained polarizing plate sample are measured by a spectrocolorimeter (CM3700d manufactured by Konica Minolta) by the SCI method.

The T ₁ / T _{2 of the} polarizing plate and the color difference ΔE (a ^* b ^* ) can be adjusted by the type and content of the dye compound represented by the general formula (1).

(Manufacturing method of polarizing plate 100)
The polarizing plate 100 can be obtained through a step of bonding the polarizing element 101 and the optical film 102 of the present invention via an adhesive. As the adhesive, a water-based adhesive or an ultraviolet curable adhesive is used.

<Water-based adhesive>
Examples of the water-based adhesive include a water-based adhesive containing a polyvinyl alcohol-based resin (such as a completely saponified polyvinyl alcohol aqueous solution).

<UV curable adhesive>
The ultraviolet curable adhesive composition may be a photoradical polymerization type composition, a photocationic polymerization type composition, or a hybrid type composition in which they are used in combination.

Examples of the photoradical polymerization type composition include a radically polymerizable compound containing a polar group such as a hydroxy group or a carboxy group described in JP-A-2008-09329, and a radically polymerizable compound containing no polar group. Compositions containing) are included.

The radically polymerizable compound is preferably a compound having an ethylenically unsaturated bond capable of radical polymerization. Preferred examples of compounds having a radically polymerizable ethylenically unsaturated bond include compounds having a (meth) acryloyl group. Examples of compounds having a (meth) acryloyl group include N-substituted (meth) acrylamide-based compounds and (meth) acrylate-based compounds. (Meta) acrylamide means acryamide or methacrylamide.

Examples of the photocationic polymerization type composition include (α) a cationically polymerizable compound, (β) a photocationic polymerization initiator, and (γ) a wavelength longer than 380 nm as disclosed in JP-A-2011-028234. Includes a photosensitizer that exhibits maximum absorption of light, and an ultraviolet curable adhesive composition containing a (δ) naphthalene-based photosensitizer.

Hereinafter, an example of using an ultraviolet curable adhesive will be described. In the polarizing plate 100 of the present invention, 1) a step of performing a pretreatment for easy adhesion on the adhesive surface of the optical film and the opposing film (pretreatment step), and 2) a polarizer and the optical film (or the opposing film) are attached. It can be obtained through a step of bonding via an ultraviolet adhesive and a step of 3) irradiating the laminated product obtained by bonding with ultraviolet rays to cure the ultraviolet adhesive (curing step).

(1) Pretreatment step Easy adhesion treatment is performed on the bonding surface between the optical film and the polarizer of the opposing film. Examples of the easy-adhesion treatment include corona treatment and plasma treatment.

(2) Laminating step An ultraviolet curable adhesive is applied to at least one of a polarizing element and an optical film (or an opposing film). The method of 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.

Then, the polarizer and the optical film or the opposing film are bonded together via an ultraviolet curable adhesive. Then, both sides of the laminated laminate are sandwiched between pressure rollers and the like to pressurize. As the material of the pressure roller, metal or rubber can be used.

(3) Curing Step Next, the laminate bonded via the ultraviolet curable adhesive is irradiated with ultraviolet rays to cure the ultraviolet curable adhesive. As a result, the polarizer and the optical film or the opposing film are adhered to each other via an ultraviolet curable adhesive. The curing of the ultraviolet curable adhesive on one side of the polarizer and the curing of the ultraviolet curable adhesive on the other side of the polarizer may be performed sequentially or at the same time. From the viewpoint of increasing the production efficiency of the polarizing plate, it is preferable that the curing of the ultraviolet curable adhesive on one side of the polarizer and the curing of the ultraviolet curable adhesive on the other side of the polarizer are performed at the same time.

It irradiation condition of the ultraviolet ray may be any conditions that ultraviolet curable adhesive is cured, for example, be integrated light quantity in the range of 50 ~ 1500mJ / cm ² is preferably in the range of 100 ~ 500mJ / cm ² Is more preferable.

The line speed at the time of manufacturing the polarizing plate depends on the curing time of the adhesive, but is preferably in the range of, for example, 1 to 500 m / min, and more preferably in the range of 5 to 300 m / min. When the line speed is 1 m / min or more, the productivity can be easily increased and the damage to the optical film and the opposing film can be further reduced. Further, when the line speed is 500 m / min or less, the ultraviolet curable adhesive is sufficiently cured, and good adhesiveness can be easily obtained.

In this way, in the curing process, a high temperature environment may occur due to irradiation with ultraviolet rays or heating to promote curing. Further, even when the adhesive is a water-based adhesive, a high temperature environment may occur due to heating for promoting adhesion or drying the adhesive.

On the other hand, since the optical film of the present invention is excellent in light resistance and durability, it is possible to obtain a polarizing plate in which light leakage is suppressed even in an environment where the temperature is high when the polarizer and the optical film are bonded. Can be done. By suppressing the light leakage of the polarizing plate, it is possible to suppress a slight light leakage due to the reflection of external light at the time of black display in the organic EL image display device having the polarizing plate.

[7] Image Display Device The optical film of the present invention can be used as an optical film (phase difference film, protective film) of an image display device such as an organic EL image display device or a liquid crystal display device. Above all, the optical film of the present invention can be preferably used as a retardation film (λ / 4 retardation film) of an organic EL image display device.

[7.1] Organic EL Image Display Device FIG. 2 is an exploded cross-sectional view of the organic EL image display device 200.

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 arranged between them.

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

The metal electrode 302 can function as a cathode. For the metal electrode 302, in order to facilitate electron injection and increase the luminous efficiency, it is preferable to use a substance having a small work function, and Mg-Ag and Al-Li are usually used.

The light emitting layer 303 is a laminate of organic thin films, 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, or such a light emitting layer. It may be a laminate of an electron injection layer composed of a perylene derivative or the like, a hole injection layer thereof, a light emitting layer, a laminate of an electron injection layer, or the like.

The transparent electrode 304 can function as an anode. The transparent electrode 304 can usually be made of a transparent conductor such as indium tin oxide (ITO).

Then, 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, and the energy generated by the recombination of these holes and electrons excites the fluorescent substance. Then, when the excited fluorescent substance returns to the ground state, it emits light and emits light.

The polarizing plate 100 is arranged on the surface of the organic EL element 300 on the visual side. The polarizing plate 100 is the above-mentioned polarizing plate 100 (see FIG. 1), and the optical film 102 (λ / 4 retardation film) is arranged so as to be located between the organic EL element 301 and the polarizer 101. There is. As described above, the angle formed by the transmission axis (or absorption axis) of the polarizer 101 and the in-plane slow phase axis of the optical film 102 is preferably 45 ° (or 135 °).

It is preferable that the opposing film 103 further has a hard coat layer (not shown) arranged on the surface on the visual side (the surface opposite to the polarizer 101). The hard coat layer can not only prevent scratches on the surface of the organic EL image display device, but also reduce the warp of the polarizing plate 100. Further, an antireflection layer may be further formed on the hard coat layer.

The adhesive layer 400 is arranged between the organic EL element 300 and the polarizing plate 100, and these are adhered to each other. Examples of the adhesive constituting the adhesive layer 400 include a heat-curable adhesive (epoxy-based heat-curable adhesive, urethane-based heat-curable adhesive, acrylic-based heat-curable adhesive, etc.), hot-melt adhesive, and the like. (Rubber-based hot-melt adhesive, polyester-based hot-melt adhesive, polyolefin-based hot-melt adhesive, ethylene-vinyl acetate resin-based hot-melt adhesive, polyurethane resin hot-melt adhesive, etc.) are included.

(Action)
In such an organic EL image display device 200, when a voltage is applied to the metal electrode 302 and the transparent electrode 304, electrons are injected into the light emitting layer 303 from the metal electrode 302 serving as a cathode, and the transparent electrode 304 serving as an anode is injected. Holes are injected from the light emitting layer 303, and the two are recombined with each other in the light emitting layer 303, so that visible light emission corresponding to the light emitting characteristics of the light emitting layer 303 is generated. The light generated in the light emitting layer 303 is directly reflected by the metal electrode 302 or then taken out to the outside through the transparent electrode 304 and the polarizing plate 100.

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 also transmits light almost completely like the transparent electrode 304. As a result, the light that is incident from the outside of the organic EL image display device 200 when it is not emitting light, 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. It passes through the light emitting layer 303, the transparent electrode 302, and the sealing layer 305 again, and tries to come out to the surface 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 to the surface side of the organic EL image display device 200, thereby reducing the reflection of external light.

That is, when the light is not emitted, half of the external light incident from the outside of the organic EL image display device 200 due to indoor lighting or the like is absorbed by the polarizing element 101 of the polarizing plate 100, but the other half is not absorbed and is straight. It is transmitted as polarized light and incident on the optical film 102 (λ / 4 retardation film). Since the light incident on the optical film 102 intersects the transmission axis of the polarizer 101 and the in-plane slow-phase axis of the optical film 102 at 45 ° (or 135 °), the transmitted light is converted into circularly polarized light. NS.

When the circularly polarized light emitted from the optical film 102 is mirror-reflected by the metal electrode 302 of the organic EL element 300, the phase is reversed by 180 degrees and becomes circularly polarized light in the opposite direction. When the reflected light is incident on the optical film 102, it is converted into linearly polarized light perpendicular to the transmission axis of the polarizer 101 (parallel to the absorption axis), so that the reflected light is absorbed by the polarizer 101 and emitted to the outside. Can be suppressed.

Then, in the present invention, an optical film 102 containing a specific dye compound is used. As a result, the optical film 102 (the cycloolefin-based resin film containing no dye compound could not be converted into the desired linearly polarized light) is perpendicular to the transmission axis of the polarizer 101 even for light in a specific wavelength region ( It can be converted to linearly polarized light (parallel to the absorption axis). As a result, it is possible to suppress a decrease in the tint of the reflected light due to the reflected light in a specific wavelength region passing through the transmission axis of the polarizer 101 and leaking. Further, the optical film 102 is excellent in light resistance even if it contains a dye compound, and display unevenness due to this can be suppressed.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In the examples, the indication of "parts" or "%" is used, but unless otherwise specified, it indicates "parts by mass" or "% by mass".

[Example 1]
1. 1. Optical film material (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 put into a reaction vessel. Then, 25 mmol% of ethylhexanoate-Ni dissolved in toluene (vs. monomer mass), 0.225 mol% of tri (pentafluorophenyl) boron (vs. monomer mass), and 0.25 mol% of triethylaluminum dissolved in toluene (vs.). The monomer mass) was put into a reaction vessel and reacted for 18 hours with stirring at room temperature. After completion of the reaction, the reaction mixture was poured into excess ethanol to form a polymer precipitate. The precipitate was purified and the obtained solid was dried in 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.

(2) Dye compound The example dye compounds and comparative compounds shown in Table I were prepared, and the energy level (eV) of HOMO was calculated.

The calculation of the energy level of HOMO by the molecular orbital calculation of the exemplary dye compound and the comparative compound having the structure represented by the general formula (1) is calculated by using B3LYP as a general function and 6-31G (d) as a basis function. It can be calculated by using the molecular orbital calculation software using the above, and the software is not particularly limited, and any of them can be used in the same manner.

In the present invention, the calculation was performed using Gaussian 09 (Revision C.01, MJ Frisch, et al, Gaussian, Inc., 2010.) manufactured by Gaussian, USA as software for calculating the molecular orbital. The HOMO energy level values of the calculation results are shown in Table I.

<< Example of dye compound synthesis >>

1 g of compound (9-1) and 0.277 g of malononitrile were measured in 100 mL of 3-headed corben, and 18 mL of toluene was added to dissolve them. Next, 0.332 g of morpholine was added dropwise, the temperature was raised, and the mixture was heated under reflux for 4 hours. After completion of the reaction, the solvent was removed under reduced pressure, 5 mL of methanol was added, and the mixture was stirred in a suspended state. The precipitate was filtered and dried to obtain 0.33 g (yield 28%) of the powder of Exemplified Dye Compound 9. The structure was confirmed by NMR.

Weighed 1 g of compound (23-1) and 0.497 g of malononitrile in 100 mL of 3-headed corben, and added 40 mL of toluene to dissolve it. Next, 0.596 g of morpholine was added dropwise, the temperature was raised, and the mixture was heated under reflux for 4 hours. After completion of the reaction, the solvent was removed under reduced pressure, 5 mL of methanol was added, and the mixture was stirred in a suspended state. The precipitate was filtered and dried to obtain 0.24 g (yield 18%) of the powder of the exemplary dye compound 23. The structure was confirmed by NMR.

(Measurement of maximum absorption wavelength)
The maximum absorption wavelength of the above compound was determined by measuring the absorption spectrum of the dye compound in dichloromethane using an ultraviolet-visible spectrophotometer UV-2450 manufactured by Shimadzu Corporation, and is shown in Table II.
The "maximum absorption wavelength" in the invention means a wavelength (nm) showing the maximum and maximum absorbance (absorption intensity) in the absorption spectrum of the compound obtained when the absorption spectrum of the compound is measured.

2. Fabrication and evaluation of optical film <Manufacture of optical film 101>
(Preparation of fine particle additive liquid)
The following components were stirred and mixed with a dissolver for 50 minutes, and then dispersed with menton golin. Further, the particles were dispersed by an attritor so that the particle size of the secondary particles became a predetermined size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution.

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 mass Ethanol: 48 parts by mass

(Preparation of dope)
The following components were put into a closed container with sufficient stirring, then heated to 80 ° C. and held for 1 hour. Then, this was cooled to 30 ° C., and then filtered through a filter having a pore size of 5 μm to obtain Dope A-1.

Cycloolefin resin 1: 100 parts by mass Dichloromethane: 302 parts by mass Ethanol: 18 parts by mass Example dye compound 1: 0.1 parts by mass Fine particle additive: 10 parts by mass

(Manufacturing of Optical Film 101)
The prepared dope is cast from a casting die on an endless metal support driven at a speed of 30 m / min, and a dry air of 40 ° C. is blown on the support to provide a self-supporting casting film. It was dried until a (film-like substance) was obtained. Then, the mixture 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 the direction of 45 ° (diagonal direction) with respect to the width direction at a stretching ratio of 2 times. As a result, an optical film 101 having a film thickness of 40 μm and having an in-plane delayed phase axis in a direction of about 45 ° with respect to the width direction was obtained.
It was confirmed that the optical film 101 is a film having a retardation value Ro of 145 nm and functioning as a λ / 4 plate by the above-mentioned retardation value evaluation method.

<Manufacturing of optical films 102 to 119>
In the production of the optical film 101, the optical films 102 to 119 were produced in the same manner except that the exemplary dye compounds were changed as shown in Table III.

≪Evaluation≫
<Light transmittance>
The light transmittance was measured using a spectrophotometer (Hitachi High-Tech Science U-3300) according to JIS K 7375: 2008 "Plastic-How to determine total light transmittance and total light reflectance". When the light transmittance was 80% or more, it was set as “◯”, and when it was less than 80%, it was set as “Δ”.

<Light resistance test>
The optical film produced above was subjected to a light resistance test.
The prepared film was continuously irradiated with light from a xenon lamp (60 W / m ² ) for 100 hours, and the absorbance of the thin film before (0 hours) and after (100 hours) irradiation was measured with a spectrophotometer. The dye residual rate was measured according to (1).
Equation (1) Dye residual rate (%) = {(A ₁₀₀ ) / (A ₀ )} × 100
(However, A ₀ is the absorbance before irradiation with the xenon lamp, and A ₁₀₀ is the absorbance after irradiation with the xenon lamp.)
The "absorbance" represents the absorbance of each compound at the maximum absorption wavelength, and the higher the dye residual ratio, the more difficult the compound is decomposed by light and the higher the light resistance. The light resistance was evaluated according to the following criteria.

A: Dye residual rate is 65% or more B: Dye residual rate is 40% or more and less than 65% C: Dye residual rate is 10% or more and less than 40% D: Dye residual rate is less than 10%

<Durability: Evaluation of bleed-out>
After each optical film is left in a high temperature and high humidity atmosphere of 60 ° C. and 90% RH for 1000 hours, the presence or absence of bleed-out (crystal precipitation) on the surface of the optical film is visually observed, and the bleed-out is performed according to the criteria described below. Evaluation was performed.

⊚: No bleed-out is observed on the surface of the optical film ○: Slight bleed-out is observed on the surface of the optical film Δ: Slight bleed-out is observed on the entire surface of the optical film × : Table III shows the composition of the optical film in which clear bleed-out is observed over the entire surface of the optical film and the above evaluation results.

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

[Example 2]
<Manufacturing of optical film 201>
Urethane acrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., UA-1100H) 19.7 parts by mass, photopolymerization initiator (manufactured by BASF, Irgacure 184) 0.1 parts by mass, modified silicone (manufactured by Shin-Etsu Chemical Co., Ltd. KF-351A) 0. 3 parts by mass, Emargen 404 (manufactured by Kao Chemical Co., Ltd.) 0.05 parts by mass, propylene glycol monomethyl ether (PGME) 39.5 parts by mass, methyl acetate 39.5 parts by mass, exemplified dye compound 6 0.1 parts by mass. The composition for coating was prepared by mixing and stirring well. The obtained coating composition was applied on a 25 μm-thick COP substrate with a wire bar, dried, and UV-cured to produce an optical film 201 having a functional layer (hard coat layer) with a thickness of 5 μm. ..

<Manufacturing of optical films 202-212>
In the production of the optical film 201, the optical films 202 to 212 were produced in the same manner except that the exemplary dye compounds were changed as shown in Table IV.
The optical films 201 to 212 produced were evaluated for light resistance and durability in the same manner as in Example 1. The results are shown in Table IV.

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

[Example 3]
The polarizing plate was prepared and evaluated using the optical films prepared in Examples 1 and 2.

<Preparation of polarizing plate 301>
(1) Preparation of Polarizer A long polyvinyl alcohol film with a thickness of 60 μm is continuously conveyed via a guide roll and immersed in a dyeing bath (30 ° C.) containing iodine and potassium iodide for dyeing treatment. After 5 times stretching treatment, in an acidic bath (60 ° C.) to which boric acid and potassium iodide were added, a total of 5 times stretching treatment and cross-linking treatment were carried out, and iodine having a thickness of 12 μm was obtained. -The PVA-based polarizer was dried in a dryer at 50 ° C. for 30 minutes to obtain a polarizer having a moisture content of 4.9%.

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

(3) Preparation of Polarizing Plate After corona treatment is applied to the bonded surface of the optical film 101, the UV-curable adhesive prepared above is applied to a coating device equipped with a chamber doctor so that the drying thickness becomes 3 μm. Was applied to. Further, the bonded surface of Konica Minolta Tack KC4CT (thickness 40 μm, manufactured by Konica Minolta Co., Ltd.) as an opposing film is similarly subjected to corona treatment, and then the above-mentioned ultraviolet curable adhesive is applied to a dry thickness of 3 μm. It was applied so as to become.

Immediately after that, the optical film 101 is bonded to one surface of the produced polarizing element, and the TAC film, which is an opposing film, is bonded to the other surface by a roll-to-roll method via an ultraviolet curable adhesive. rice field. The bonding is performed so that the slow axis (or phase advance axis) of the optical film 101 and the absorption axis (or transmission axis) of the polarizer coincide with each other (the in-plane slow axis of the optical film 101 and the absorption axis of the polarizer). The angle between the two was 45 °). Then, while transporting the bonded material at a line speed of 20 m / min, ultraviolet rays were irradiated from the optical film 106 side by a metal halide lamp so that the ^{integrated light amount at a wavelength of 280 to 320 nm was 320 mJ / cm 2.} As a result, the ultraviolet curable adhesive was cured to obtain a polarizing plate 301. Since the polarizing plate 301 is manufactured by a roll-to-roll method, the elongated polarizing plate is finally cut along the width direction to obtain a sheet-shaped polarizing plate 301.

The produced polarizing plate 301 is attached to a portion of a commercially available organic EL image display device on which the polarizing plate on the visual side is peeled off so that the optical film 101 side of the polarizing plate is on the organic EL element side, and the organic EL image is displayed. The device 301 was manufactured.

<Manufacturing of Polarizing Plates and Organic EL Image Display Devices 302 to 319>
In the production of the polarizing plate 301, the polarizing plates 302 to 319 and the organic EL image display devices 302 to 319 were produced in the same manner except that the optical film 101 was changed as shown in Table V.
The prepared polarizing plates 301 to 319 and the organic EL image display devices 301 to 319 were evaluated in the same manner as in Example 1 and the following light leakage evaluation, and the results are shown in Table V.

<Light leakage evaluation>
The organic EL image display device produced above is stored in an environment of 60 ° C. and 90% RH for 500 hours, then placed at room temperature and humidity (23 ° C. and 55% RH) for 24 hours, and displayed in black in a dark room. The appearance of display unevenness due to light leakage from the screen at that time was visually observed and evaluated according to the following criteria.
◯: No display unevenness due to light leakage Δ: Some display unevenness is observed due to light leakage ×: Display unevenness clearly occurs due to light leakage

From Table V, it was found 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 having no light leakage can be obtained.

The optical film of the present invention has high transparency, prevents light leakage, and is excellent in light resistance and durability under harsh environmental conditions, so that it can be suitably used for polarizing plates and organic electroluminescence image display devices.

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

An optical film containing a thermoplastic resin.
An optical film containing a compound having a structure represented by the following general formula (1).

(In the formula, Z represents a heteroaryl group having two or more heteroatoms, and may have a substituent.)
The optical film according to claim 1, wherein Z is any group represented by the following structural formula.

(The group represented by the above structural formula may further have a substituent. In addition, R represents a substituent.)
The optical film according to claim 2, wherein Z is any group represented by the following structural formula.

(The group represented by the above structural formula may further have a substituent. In addition, R represents a substituent.)
Any one of claims 1 to 3, wherein the energy level of the highest occupied molecular orbital of the compound having the structure represented by the general formula (1) is −5.85 ev or less. The optical film described in.
The optical film according to any one of claims 1 to 4, wherein the thermoplastic resin is a cyclic olefin resin or an acrylic resin.
The optical film according to claim 5, wherein the cyclic olefin resin has a polar group.
Claims 1 to 6 are characterized in that the compound having the structure represented by the general formula (1) is contained in the range of 0.01 to 20% by mass with respect to the thermoplastic resin. The optical film according to any one of the above.
The optical film according to any one of claims 1 to 7, further comprising a functional layer.
The optical film according to claim 8, wherein the functional layer contains a compound having a structure represented by the general formula (1).
The optical film according to any one of claims 1 to 9, wherein the optical film is a λ / 4 retardation film.
A polarizing plate comprising the optical film according to any one of claims 1 to 10.
An organic electroluminescence image display device comprising the optical film according to any one of claims 1 to 10 or the polarizing plate according to claim 11.