JP2003026668A - Benzotriasole, ultraviolet light absorber, optical film, method for producing the same, polarizing plate and display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a benzotriazole used as an ultraviolet light absorber, having a low melting point and low volatility, excellent in compatibility with a resin, and scarcely bleeding out. SOLUTION: This benzotriazole is expressed by formula (I) [R1 to R4 are each H, a halogen or a 1-8C straight chain (or branched chain) alkyl (or alkoxyl); and R5 and R6 are each a 1-24C straight chain (or branched chain) alkyl, provided that the total of the carbon numbers of R5 and R6 is not less than 11].

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a benzotriazole, an ultraviolet absorber, an optical film, a method for producing the same, a polarizing plate using the same, and a display device.

[0002]

To date, plastics are superior in lightness, workability, electrical insulation, water resistance, chemical resistance, mechanical strength, etc., and thus, plastics are used for electric appliances, automobile parts, and mechanical parts. Widely used in various fields such as, toys and household items. These types of plastics include phenolic resin, melamine resin, epoxy resin,
It has been developed and manufactured over a wide variety of thermosetting resins such as polyurethane and polyimide, and thermoplastic resins such as vinyl chloride, polyvinyl acetal, polyethylene, polypropylene, AS, ABS, PET and polycarbonate.

By the way, these resins have a problem that peroxides are generated due to ultraviolet rays or heat and the quality is deteriorated.

Therefore, an ultraviolet absorber such as a benzotriazole-based compound, a benzophenone-based compound, a benzoate-based compound, or a salicylic acid-based compound has been used as an additive that suppresses a radical chain reaction that causes deterioration of resin quality. It was Regarding the ultraviolet absorber,
For example, JP-A-6-130226 and JP-A-7-11
It is also proposed in Japanese Patent No. 056.

However, these ultraviolet absorbers impair the stability during molding due to bleed-out or the like bleeding out on the resin surface, or evaporate during molding, so that a satisfactory ultraviolet absorbing ability is obtained. There was a problem that a large amount had to be added.

Generally, also in an optical film, an ultraviolet absorber such as a benzotriazole-based compound or a benzophenone-based compound, a cyanoacrylate-based compound, a salicylic acid-based compound is mixed in advance to form a film, and thereby an ultraviolet ray is emitted. Cut to prevent deterioration of the liquid crystal and polarizer. In recent years, development of large screens, high definition, and thin and lightweight laptop computers and liquid crystal monitors has been advanced. Along with this, there is an increasing demand for higher performance and thinner film for protective films for polarizing plates for liquid crystals.

However, even if the film is thinned, it is required that the ultraviolet blocking ability required for the optical film is not changed, and as a result, the thinner the film, the ratio of the ultraviolet absorber to the total solid content of the optical film. Is on the rise.

Most of the ultraviolet absorbers proposed so far have had a problem of contaminating the inside of the film forming process when the amount added is increased. When the inside of the process is contaminated with the ultraviolet absorber, the contaminants adhere to the transport roll and are pushed and cause a failure, which causes a decrease in the yield of the optical film.

Further, with the increase in definition, the surface quality characteristics required for optical films have become more severe. Therefore, when the optical film is produced, the film is stretched in the width direction with a tenter to enhance the smoothness of the film and produce a film having excellent surface properties. At this time, it is more effective to perform the widthwise stretching by the tenter while applying heat in the presence of a high residual solvent. However, when heat is applied in the presence of a high solvent residue, evaporation of the ultraviolet absorber is likely to occur at the same time, and as a result, the amount of the ultraviolet absorber added is reduced, the ultraviolet absorption performance is deteriorated, and the manufacturing process is contaminated. Was causing various problems.

Therefore, the first problem to be solved by the present invention is to provide an ultraviolet absorber having a low melting point, a low volatility, an excellent compatibility with a resin, and a bleed out hardly occurring. Is.

A second problem to be solved by the present invention is
Excellent in light resistance and surface property, no process contamination, roll stain,
It is an object of the present invention to provide an optical film with reduced pressing failure.

A third problem to be solved by the present invention is
Excellent in light resistance and surface property, no process contamination, roll stain,
It is an object of the present invention to provide a polarizing plate using an optical film in which pressed failures are reduced.

A fourth problem to be solved by the present invention is
Excellent in light resistance and surface property, no process contamination, roll stain,
It is an object of the present invention to provide a display device using an optical film in which pressed failures are reduced.

[0014]

The first problem is solved by a benzotriazole which is represented by the following general formula [I].

Further, it is solved by an ultraviolet absorber characterized by containing a benzotriazole represented by the following general formula [I] as an active ingredient.

General formula [I] [In the general formula [I], R _{1 to} R ₄ are hydrogen atoms, halogen atoms, or linear (or branched) alkyl groups (or alkoxy groups) having 1 to 8 carbon atoms, and R ₅ and R ₆ are Carbon number 1
24 straight chain (or branched) alkyl groups. However, R
The sum of the carbon number of _{5 and} the carbon number of R ₆ is 11 or more. ] Especially, it is solved by benzotriazole characterized by being represented by the following general formula [I].

Further, it is solved by an ultraviolet absorber characterized by containing benzotriazole represented by the following general formula [I] as an active ingredient.

General formula [I] [In the general formula [I], R _{1 to} R ₄ are hydrogen atoms, halogen atoms, or linear (or branched) alkyl groups (or alkoxy groups) having 1 to 8 carbon atoms, and R ₅ and R ₆ are 6-carbon
10 straight-chain alkyl groups. The second problem is solved by an optical film containing a compound represented by the above general formula [I] or the following general formula [II].

In particular, it is solved by an optical film containing a cellulose ester and a compound represented by the above general formula [I] or the following general formula [II].

In the method for producing an optical film using the solution casting method, a resin solution containing a compound represented by the above general formula [I] or the following general formula [II] is flown on a support. Roll it out, peel it off after drying, and set it to 0 in the width direction with a tenter.
This is solved by a method for producing an optical film, which comprises stretching 100% to 100%.

In particular, in a method for producing an optical film using a solution casting method, a resin solution containing a compound represented by the above general formula [I] or the following general formula [II] and methyl acetate is used as a support. This is solved by a method for producing an optical film, which comprises casting on top, peeling after drying, and stretching in the width direction by 0 to 100% with a tenter.

General formula [II] [In the general formula [II], X is a halogen atom, Y is a branched alkyl group having 10 to 26 carbon atoms, and R ₂ , R ₃ ,
R ₄ is a hydrogen atom or an alkyl group which may have a substituent. Further, the present invention is solved by an optical film manufactured by the above-mentioned method for manufacturing an optical film.

The third problem is solved by a polarizing plate having the above optical film.

The fourth problem is solved by a display device characterized by using the above-mentioned optical film.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The benzotriazole according to the present invention is a compound represented by the following general formula [I], especially [IA].

General formula [I] [In the general formula [I], R _{1 to} R ₄ are hydrogen atoms, halogen atoms, or linear (or branched) alkyl groups (or alkoxy groups) having 1 to 8 carbon atoms, and R ₅ and R ₆ are Carbon number 1
24 straight chain (or branched) alkyl groups. However, R
The sum of the carbon number of _{5 and} the carbon number of R ₆ is 11 or more. ] General formula [IA] [In the general formula [IA], R _{1 to} R ₄ are a hydrogen atom, a halogen atom, or a linear (or branched) alkyl group (or an alkoxy group) having 1 to 8 carbon atoms, and R ₅ and R ₆ are Carbon number 6
It is a linear alkyl group of -10. The ultraviolet absorbent according to the present invention contains the benzotriazole represented by the above general formula [I], particularly [IA], as an active ingredient.

The optical film according to the present invention contains a compound represented by the above general formula [I], particularly [IA] or the following general formula [II]. In particular, it contains a compound represented by the above general formula [I], particularly [IA] or the following general formula [II], and a cellulose ester. Further, it is manufactured by the following manufacturing method.

General formula [II] [In the general formula [II], X is a halogen atom, Y is a branched alkyl group having 10 to 26 carbon atoms, and R ₂ , R ₃ ,
R ₄ is a hydrogen atom or an alkyl group which may have a substituent. The method for producing an optical film according to the present invention is the compound represented by the above general formula [I], particularly [IA] or general formula [II], in the method for producing an optical film using a solution casting film forming method. Is a casting method in which a resin solution containing is cast on a support, peeled after drying, and stretched in the width direction by 0 to 100% by a tenter. In particular, in a method for producing an optical film using a solution casting method, a resin solution containing a compound represented by the above general formula [I], particularly [IA] or general formula [II], and methyl acetate is used as a support. It is a manufacturing method in which it is cast on the surface, dried, peeled off, and stretched in the width direction by 0 to 100% by a tenter.

The polarizing plate according to the present invention has the above optical film.

A display device according to the present invention uses the above optical film.

The present invention will be described in more detail below.

R _{1 to} R ₄ in the above general formula [I] representing benzotriazole (ultraviolet absorber) according to the present invention.
Is a hydrogen atom, a halogen atom, or a linear (or branched) alkyl group (or alkoxy group) having 1 to 8 carbon atoms. Examples of the halogen atom include Cl, Br and F, but Cl is particularly preferable. Examples of the linear (or branched) alkyl group having 1 to 8 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group, an n-butyl group, an iso-butyl group, a sec-butyl group, tert-
Butyl group, n-pentyl group, iso-pentyl group, se
A c-pentyl group, a tert-octyl group, a 2-ethylhexyl group and the like can be mentioned. Examples of the linear (or branched) alkoxy group having 1 to 8 carbon atoms include methoxy group, ethoxy group, n-propoxy group, iso-propoxy group,
n-butoxy group, iso-butoxy group, sec-butoxy group, tert-butoxy group, n-pentyloxy group,
Examples thereof include sec-pentyloxy group, tert-octyloxy group and 2-ethylhexyloxy group.

R ₅ and R ₆ in the general formula [I] are linear (or branched) alkyl groups having 1 to 24 carbon atoms. However, the total of the carbon number of R _{5 and} the carbon number of R ₆ is 11 or more. Examples of this type of alkyl group include a methyl group, an ethyl group, an n-propyl group, an iso-propyl group,
n-butyl group, iso-butyl group, sec-butyl group,
tert-butyl group, n-pentyl group, iso-pentyl group, sec-pentyl group, tert-octyl group, 2
-Ethylhexyl group, nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, hexadecyl group, octadecyl group, nonadecyl group, eicosyl group, heneicosyl group, docosyl group,
Examples thereof include tricosyl group and tetracosyl group. Of these, a linear alkyl group having 6 to 10 carbon atoms is particularly preferable.

The benzotriazole according to the present invention is obtained as follows.

[Synthesis Example 1] The benzotriazole of the present invention can be obtained by diazotizing o-nitroaniline, coupling it with resorcin monoethers to produce a nitroazo compound by a conventional method, and reducing it. [Synthesis Example 2] O-nitroaniline was diazotized and coupled with resorcins by a conventional method to obtain a nitroazo compound, which was reduced to give 2- {2 ', 4'-dihydroxy (alkyl) phenyl} benzotriazole. And

For example, R ₁ is a chlorine atom, R ₂ , R ₃ and R
2- (2 ', 4'-dihydroxyphenyl) -5-chlorobenzotriazole, in which ₄ is a hydrogen atom, is an existing chemical substance, and an etherifying agent (in the formula, X is a halogen atom, an alkyl or aryl sulfonate). Etc., which represents an etherifying agent residue), to give the benzotriazole of the present invention. Hereinafter, some specific examples of the benzotriazole of the present invention synthesized by the above synthesis method will be described. The present invention is not limited to these. UV-I-1 UV-I-2 UV-I-3 UV-I-4 UV-I-5 UV-I-6 UV-I-7 UV-I-8 UV-I-9 UV-I-10 UV-I-11 UV-I-12 The ultraviolet absorber according to the present invention may be only the above compounds, but may contain additives such as an antioxidant, a light stabilizer and a metal deactivator. Furthermore, if necessary, various fillers, conductive powders, etc. may be contained.

As the antioxidant, for example, 2,6-di-
tert-butyl-4-methylphenol, 2-ter
t-Butyl-4,6-dimethylphenol, 2,6-di-tert-butyl-4-ethylphenol, 2,6-
Di-tert-butyl-4-n-butylphenol,
2,6-di-tert-butyl-4-isobutylphenol, 2,6-dicyclopentyl-4-methylphenol, 2- (α-methylcyclohexyl) -4,6-dimethylphenol, 2,6-dioctadecyl- 4-methylphenol, 2,4,6-tricyclohexylphenol, 2,6-dinonyl-4-methylphenol, 2,6
-Di-tert-butyl-4-methoxymethylphenol, 2,4-dimethyl-6- (1'-methyl-undeca-1'-yl) -phenol, 2,4-dimethyl-6-
(1'-Methyl-trideca-1'-yl) -phenol and mixtures thereof, 2,4-di-octylthiomethyl-6-tert-butylphenol, 2,4-di-octylthiomethyl-6-ethylphenol , 2,6-di-
Dodecylthiomethyl-4-nonylphenol and mixtures thereof, 2,6-di-tert-butyl-4-methoxyphenol, 2,5-di-tert-butylhydroquinone, 2,5-di-tert-amylhydroquinone, 2 , 6-Di-phenyl-4-octadecyloxyphenol, 2,6-di-tert-butylhydroquinone, 2,5-di-tert-butyl-4-hydroxyanisole, 3,5-di-tert-butyl-4. -Hydroxyanisole, 3,5-di-tert-butyl-4-
Hydroxyphenyl stearate, bis (3,5-di-
tert-Butyl-4-hydroxyphenyl) adipate and mixtures thereof, 2,4-bis-octylmercapto-6- (3,5-di-tert-butyl-4-hydroxyanilino) -1,3,5- Triazine, 2-octyl mercapto-4,6-bis (3,5-di-tert.
-Butyl-4-hydroxyanilino) -1,3,5-triazine, 2-octylmercapto-4,6-bis (3,5-di-tert-butyl-4-hydroxyphenoxy) -1,3,5 -Triazine, 2,4,6-tris (3,5-di-tert-butyl-4-hydroxyphenoxy) -1,2,3-triazine, 1,3,5-tris (3,5-di-tert) -Butyl-4-hydroxybenzyl) -isocyanurate, 1,3,5-tris (4-tert-butyl-3-hydroxy-2,6-dimethylbenzyl) -isocyanurate, 2,4,6-tris (3 , 5-Di-tert-butyl-4-hydroxyphenylethyl) -1,3,5-triazine, 1,3,
5-tris (3,5-di-tert-butyl-4-hydroxyphenylpropionyl) -hexahydro-1,
3,5-triazine, 1,3,5-tris (3,5-dicyclohexyl-4-hydroxybenzyl) -isocyanurate, 2,2′-methylenebis (6-tert-butyl-4-methylphenol), 2, 2'-methylenebis (6-tert-butyl-4-ethylphenol),
2,2'-ethylidene bis (4,6-di-tert-butylphenol), 2,2'-ethylidene bis (6-t
ert-butyl-4-isobutylphenol), 4,
4'-methylenebis (2,6-di-tert-butylphenol), 4,4'-methylenebis (6-tert-
Butyl-2-methylphenol), 1,1-bis (5-
tert-Butyl-4-hydroxy-2-methylphenyl) butane, ethylene glycol bis [3,3′-bis (3′-tert-butyl-4′-hydroxyphenyl) butyrate), 1,3,5-tris ( 3,5-di-
tert-butyl-4-hydroxybenzyl) -2,
4,6-trimethylbenzene, 1,4-bis (3,5-
Di-tert-butyl-4-hydroxybenzyl)-
2,3,5,6-tetramethylbenzene, 2,4,6-
Examples include tris (3,5-di-tert-butyl-4-hydroxybenzyl) -phenol.

Examples of the light stabilizer include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (3 ', 5'-di-tert-butyl-2-hydroxyphenyl) benzotriazole, 2- [2'-
Hydroxy-5 '-(1,1,3,3-tetramethylbutyl) phenyl] benzotriazole, 2- (3',
5'-di-tert-butyl-2'-hydroxyphenyl) -5-chlorobenzotriazole, 2- (3'-t
ert-butyl-2'-hydroxy-5'-methylphenyl) 5-chlorobenzotriazole, 2- (2'-hydroxy-4'-octoxyphenyl) benzotriazole, 2- (3 ', 5'-di- tert-amyl-2 '
-Hydroxyphenyl) benzotriazole, 2-
[3'-tert-butyl-2'-hydroxy-5'-
(2'-octyloxycarbonylethylphenyl)-
5-chlorobenzotriazole, 4-hydroxy-4-
Hydroxybenzophenone derivative, 4-methoxybenzophenone derivative, 4-octoxybenzophenone derivative, 4-decyloxybenzophenone derivative, 4-dodecyloxybenzophenone derivative, 4-benzyloxybenzophenone derivative, 4,2 ', 4'-trihydroxybenzophenone derivative 2'-hydroxy-4,4 '
-Dimethoxybenzophenone derivative, 4- (2-ethylhexyloxy) -2-hydroxybenzophenone derivative, 4-tert-butylphenyl salicylate, phenyl salicylate, octylphenyl salicylate, dibenzoylresorcinol, bis (4-tert-butylbenzoylresorcinol), 2,4-di-tert
-Butylphenyl resorcinol, 3,5-di-ter
t-Butyl-4-hydroxybenzoate, hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate, ethyl-α-cyano-β, β-diphenyl acrylate, isooctyl-α-cyano-β, β-diphenyl Acrylate, methyl-α-carbomethoxycinnamate, methyl-α-cyano-β-methyl-p-methoxycinnamate, bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (2,2 Two
6,6-Tetramethyl-4-piperidyl) succinate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (1-octyloxy-)
2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4)
-Piperidyl) adipate, 4,4'-dioctyloxy oxanilide, 2,2'-diethoxyoxy oxanilide, 2,2'-dioctyloxy-5,5'-di-t
ert-butyl oxanilide, 2,2′-didodecyloxy-5,5′-di-tert-butyl oxanilide,
2-ethoxy-2'-ethyl oxanilide, N, N'-
Bis (3-dimethylaminopropyl) oxanilide, 2
-Ethoxy-5-tert-butyl-2'-ethoxyoxanilide, 2,4,6-tris (2-hydroxy-4)
-Octyloxyphenyl) -1,3,5-triazine, 2- (2-hydroxy-4-octyloxyphenyl) -4,6-bis (2,4-dimethylphenyl)-
1,3,5-triazine, 2- (2,4-dihydroxyphenyl) -4,6-bis (2,4-dimethylphenyl) -1,3,5-triazine, 2,4-bis (2-hydroxy) -4-Propyloxyphenyl) -6- (2,
4-dimethylphenyl) -1,3,5-triazine, 2
-(2-hydroxy-4-dodecyloxyphenyl)-
4,6-bis (2,4-dimethylphenyl) -1,3,
5-triazine and the like can be mentioned.

Examples of the metal deactivator include N, N'-
Di-phenyl oxalic acid diamide, N-sultyl-N '
-Salicyloyl hydrazine, N, N'-bis (salicyloyl) hydrazine, N, N'-bis (3,5-di-te
rt-Butyl-4-hydroxyphenylpropionyl)
Hydrazine, 3-salicyloylamino-1,2,3-triazole, bis (benzylidene) oxalic acid hydrazide, isophthalic acid dihydrazide, N, N'-diacetal-adipic acid dihydrazide, N, N'-bissalicyloylshu Examples thereof include acid dihydrazide and N, N′-bissalicyloylthiopropionic acid dihydrazide.

The UV absorbers described above can be added to various organic materials to form stable compositions.

Examples of the organic material include various natural resins, natural rubber, synthetic resins, synthetic rubbers, petroleum (mineral oil, synthetic oil, lubricating oil, etc.), solid forms such as paper, waxes such as fats and oils, or A liquid one can be mentioned. Examples of the synthetic resin include phenol resin, melamine resin, epoxy resin, thermosetting resin such as polyurethane and polyimide, vinyl chloride type, polyvinyl acetal, polyethylene, polypropylene, AS, ABS, PET, polycarbonate and other thermoplastic resin. Can be mentioned. Examples of synthetic rubbers include polybutadiene, polychloroprene, and butadiene block copolymers.

Next, the optical film containing the compound (ultraviolet absorber) represented by the above general formulas [I] and [II] will be explained. In particular, the above general formulas [I] and [I
The optical film containing the compound (UV absorber) represented by I] and the cellulose ester will be described.

The general formula [I] is as described above.

In the general formula [II], X is a halogen atom (F, Cl, Br, etc.). Particularly preferred is Cl.

In the general formula [II], Y has 10 carbon atoms.
~ 26 branched alkyl groups. The position of branching is arbitrary and may be branched at any position of the alkyl group, and in the case of a branched alkyl group, the α-position carbon is 1
It may be primary carbon or secondary or tertiary carbon.
Particularly preferably, the α-position carbon is a primary carbon. As Y, an alkyl group branched at the β-position is preferable. Incidentally, branched alkyl groups may be linked to each other to form a cycloalkyl group. The branched alkyl group represented by Y preferably has 12 to 20 carbon atoms, and more preferably 1 carbon atom.
4-18. In the general formula [II], R ₂ ,
When each of the substituents represented by R ₃ and R ₄ is an alkyl group, it may be linear, branched or cyclic. Moreover, these alkyl groups may further have an arbitrary substituent.

The amount of the ultraviolet absorber represented by the general formulas [I] and [II] used is not uniform depending on the kind of the compound and the use conditions, but is usually 0.2 per 1 m ² of the optical film.
~ 2g is preferred. Further, 0.4 to 1.5 g is preferable, and 0.6 to 1.0 g is particularly preferable. Specific examples of the ultraviolet absorber represented by the general formula [II] are shown below, but the invention is not limited thereto. UV-II-1 UV-II-2 UV-II-3 UV-II-4 UV-II-5 UV-II-6 UV-II-7 UV-II-8 UV-II-9 UV-II-10 UV-II-11 In the present invention, conventionally known ultraviolet absorbers may be used together with the ultraviolet absorbers represented by the above general formulas [I] and [II].

The conventionally known ultraviolet absorber is not particularly limited, and examples thereof include salicylic acid type ultraviolet absorbers (phenyl salicylate, p-tert-butyl salicylate, etc.), benzophenone type ultraviolet absorbers (2,4-dihydroxybenzophenone, 2). , 2'-dihydroxy-4,
4'-dimethoxybenzophenone, etc., benzotriazole-based ultraviolet absorber (2- (2'-hydroxy-3'-
tert-Butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-
3 ', 5'-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-
3 ', 5'-di-tert-amyl-phenyl) benzotriazole, etc.), cyanoacrylate-based UV absorber (2'-ethylhexyl-2-cyano-3,3-diphenylacrylate, ethyl-2-cyano-3-). (3 ',
4'-methylenedioxyphenyl) -acrylate, etc.), triazine-based UV absorber, or JP-A-58-
Examples thereof include compounds described in Japanese Patent No. 18567 and JP-A-59-149350, nickel complex salt compounds, and inorganic powders.

Among them, as a conventionally known ultraviolet absorber used in combination with the ultraviolet absorbers represented by the above general formulas [I] and [II], the transparency is high and the effect of preventing the deterioration of the polarizing plate and the liquid crystal element is obtained. A benzotriazole-based UV absorber and a benzophenone-based UV absorber, which are excellent in heat resistance, are preferable. In particular, a benzotriazole-based ultraviolet absorber that causes less unnecessary coloring is preferable.

The optical film of the present invention is not particularly limited and can be appropriately selected and used from known transparent resin films. Examples of such a transparent plastic film include polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyethylene film, polypropylene film, cellophane, diacetyl cellulose film, triacetyl cellulose film, cellulose acetate propionate film, cellulose acetate butyrate. Film, polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene vinyl alcohol film, polystyrene film, syndiotactic polystyrene film, norbornene resin film, polycarbonate film, polyarylate film, polymethylmethacrylate film, polyacrylate Film, polyolefin System norbornene resin film, a polymethylpentene film, polysulfone film, polyether ether ketone film, polyether sulfone film, polyether imide film, polyimide film, fluororesin film, nylon film, can be mentioned acrylic film or the like. Among them, in the present invention, particularly, cellulose ester such as cellulose triacetate film, cellulose diacetate, cellulose acetate butyrate, cellulose acetate phthalate, cellulose propionate, cellulose acetate propionate, and cellulose acetate propionate butyrate. It is preferable to use a film.

Next, a method for producing a cellulose ester film, which is a preferred embodiment of the present invention, will be described.
A preferred film forming process used for producing the cellulose ester film according to the present invention comprises a dissolving process, a casting process, a solvent evaporation process, a peeling process, a drying process and a winding process shown below.

Each step will be described below. [Dissolution Step] In the present invention, the cellulose ester solution is referred to as a cellulose ester dope or simply dope.

The dissolving step is a step of dissolving the flakes of cellulose ester in an organic solvent mainly composed of a good solvent described later in a dissolving vessel while stirring the flakes to form a dope. In the present invention, the solid content concentration in the dope is preferably 15% by mass or more, and particularly preferably 18 to 35% by mass.

If the solid content concentration in the dope is too high, the viscosity of the dope becomes too high, and sharkskin or the like may occur during casting to deteriorate the flatness of the film.
It is desirable that the content is not more than mass%.

The dope viscosity is preferably adjusted within the range of 10 to 50 Pa · s.

The dissolution is carried out at normal pressure, at a temperature below the boiling point of a preferred organic solvent (ie, a solvent), at a pressure higher than the boiling point of the above good solvent, and at a cooling dissolution method. There are various dissolution methods such as high pressure. As a method of dissolving at a temperature not lower than the boiling point of a good solvent and applying a pressure at which it does not boil, it is 0.14 at 40.4 to 120 ° C.
It suppresses foaming by pressurizing to ~ 1.50 MPa, and
It can dissolve in a short time. As the cellulose ester used in the present invention, a lower fatty acid ester of cellulose is preferably used. The lower fatty acid in the lower fatty acid ester of cellulose ester means a fatty acid having 6 or less carbon atoms, for example, cellulose acetate, cellulose propionate, cellulose butyrate, etc., and JP-A-10-45804 and JP-A-10-45804. 8-2
Examples thereof include mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate described in US Pat. No. 3,176,1 and US Pat. No. 2319052. Particularly preferred is a cellulose ester having a total degree of substitution of 2.55 to 2.85. Among the above fatty acids, cellulose acetate and cellulose acetate propionate are preferably used. Furthermore,
In the case of the cellulose ester film according to the present invention,
From the viewpoint of film strength, those having a polymerization degree of 250 to 400 are preferably used.

For the cellulose ester film according to the present invention, a cellulose ester having a total degree of substitution of 2.5 to 3.0 is preferably used, and particularly a total degree of substitution of 2.55 to 2.8.
The cellulose ester of 5 is preferably used. When the total substitution degree is 2.55 or more, the general formulas [I] and [I
When the mechanical strength of the film containing the compound represented by the formula [I] is increased to 2.85 or less, the solubility of the cellulose ester is improved and the generation of foreign matter is reduced, which is more preferable. In the case of cellulose acetate propionate, assuming that the acetyl group substitution degree is X and the propionyl group substitution degree is Y, those having a range of 2.55 ≦ X + Y ≦ 2.85 1.5 ≦ X ≦ 2.4 are preferably used. To be

As the cellulose ester, a cellulose ester synthesized from cotton linter, a cellulose ester synthesized from wood pulp, and a cellulose ester synthesized from other raw materials can be used alone or in combination.

The solvent used for preparing the dope is not particularly limited as long as it can dissolve the cellulose ester. Further, even a solvent that cannot be dissolved alone can be used as long as it can be dissolved by mixing with another solvent. Generally, a mixed solvent containing a good solvent, methylene chloride, and a poor solvent for cellulose ester is used, and a mixed solvent containing 4 to 30 mass% of the poor solvent is preferably used.

Examples of good solvents that can be used include methylene chloride, methyl acetate, ethyl acetate, amyl acetate,
Acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,2.
3,3-tetrafluoro-1-propanol, 1,3-
Difluoro-2-propanol, 1,1,1,3,3
3-hexafluoro-2-methyl-2-propanol,
1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane and the like can be mentioned,
Organic halogen compounds such as methylene chloride, dioxolane derivatives, methyl acetate, ethyl acetate, acetone and the like are mentioned as preferable organic solvents (that is, good solvents). The use of methyl acetate is particularly preferable because the resulting film has less curl.

Examples of the poor solvent for cellulose ester include methanol, ethanol, n-propanol, is
alcohols having 1 to 8 carbon atoms such as o-propanol, n-butanol, sec-butanol, and tert-butanol, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, propyl acetate, monochlorobenzene,
Examples thereof include benzene, cyclohexane, tetrahydrofuran, methyl cellosolve, and ethylene glycol monomethyl ether. These poor solvents may be used alone or in combination of two or more kinds.

In the production of the cellulose ester film according to the present invention, when the cellulose ester is dissolved,
It is also preferable to use a cooling dissolution method. Examples of the cooling dissolution method include, for example, JP-A-9-95538 and JP-A-9-95538.
The methods described in JP-A-95544 and JP-A-9-95557 can be used. In addition, JP-A-11-21
The high-pressure dissolution method described in Japanese Patent No. 379 can also be preferably used.

After the dissolved cellulose ester solution (dope) is filtered with a filter medium, it is preferable to degas and send it to the next step by a pump. At that time, a plasticizer in the dope,
Antioxidants, ultraviolet absorbers, dyes, fine particles and the like are appropriately added.

These additives may be added together with the cellulose ester or the solvent during the preparation of the cellulose ester solution, or during or after the solution preparation.

A plasticizer can be added to the cellulose ester film according to the present invention. These can be used in combination with the compounds having the structures represented by the general formulas [I] and [II].

Examples of the plasticizer that can be used include, but are not limited to, phosphoric acid ester plasticizers, phthalic acid ester plasticizers, and citric acid ester plasticizers.

Examples of the phosphoric acid ester type include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, and the like, and phthalic ester type such as diethyl ether. Phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, butyl benzyl phthalate, dibenzyl phthalate, butyl phthalyl butyl glycolate, ethyl phthalyl ethyl glycolate, methyl phthalyl ethyl There are glycolates and the like, and in citric acid ester plasticizers, for example, triethyl citrate, tri-n-butyl citrate, Cetyl triethyl citrate, acetyl tri -n- butyl citrate, acetyl tri -n-
(2-Ethylhexyl) citrate and the like can be preferably used. These plasticizers may be used alone or in combination of two or more as required.

The amount of the plasticizer used is preferably 1 to 30% by mass based on the cellulose ester. Further, 2 to 25 mass% is preferable, and 2 to 15 mass% is more preferable. It is particularly preferably 3 to 12% by mass.

The cellulose ester film according to the present invention may contain an additive having the same action as that of the plasticizer, in addition to the above plasticizer. As these additives, for example, if they are low molecular weight organic compounds capable of plasticizing the cellulose ester film, the same effects as those of the plasticizer can be obtained. These components are not added for the purpose of directly plasticizing the film as compared with the plasticizer, but show the same action as the above plasticizer depending on the amount.

Further, in the present invention, for example, a blue dye may be used as an additive in order to adjust the tint of the film. Anthraquinone dyes are preferred dyes. The anthraquinone dye can have an arbitrary substituent at the 1st to 8th positions of the anthraquinone. Preferred substituents include an anilino group, a hydroxyl group, an amino group, a nitro group, or a hydrogen atom which may be substituted. The amount of these dyes added to the film is 0.1 to 100 in order to maintain the transparency of the film.
It is 0 μg / m ² , preferably 10 to 100 μg / m ² .

Further, it is preferable to add fine particles as a matting agent to the cellulose ester film according to the present invention in order to impart slipperiness to the film. It is preferable that these fine particles are surface-treated with an organic substance because the haze of the film can be reduced. Preferred organic substances for the surface treatment include halosilanes, alkoxysilanes, silazanes, siloxanes and the like.

The larger the average diameter of the fine particles, the greater the matte effect, and the smaller the average diameter, the more excellent the transparency. Therefore, in the present invention, the average diameter of the primary particles of the fine particles is 5 to 50 nm.
Is preferable, and more preferably 7 to 20 nm.

The fine particles are not particularly limited, but for example, AEROSIL 200,2 manufactured by Nippon Aerosil Co., Ltd.
00V, 300, R972, R972V, R974, R
202, R812, OX50, TT600 and the like, and preferably AEROSIL200V, R972V and the like.

These permeable particles usually have an average particle size of 0.01.
˜1.0 μm secondary particles are formed, and these fine particles are present in the film as an agglomerate of primary particles to form irregularities of 0.01 to 1.0 μm on the film surface. The content of these fine particles is preferably 0.005 to 0.3 mass% with respect to the cellulose ester.

In particular, the cellulose ester film according to the present invention preferably contains fine particles of silicon dioxide, and a cellulose ester solution containing the ultraviolet absorbent according to the present invention and fine particles of silicon dioxide is cast to form a film. This is particularly preferable because foreign matter failure due to aggregation of fine particles in the cellulose ester solution is significantly reduced.

As a method for preparing a dispersion liquid of fine particles for obtaining the cellulose ester film according to the invention, there are, for example, the following three kinds.

[Preparation Method A] A method in which a solvent and fine particles are stirred and mixed and then dispersed by a disperser to prepare a fine particle dispersion, which is then added to a dope solution and stirred.

[Preparation Method B] A solvent and fine particles are stirred and mixed, and then dispersed by a disperser to prepare a fine particle dispersion. Separately, a small amount of cellulose ester is added to a solvent and dissolved by stirring. A method in which the above-mentioned fine particle dispersion liquid is added and stirred to prepare a fine particle addition liquid, which is then thoroughly mixed with a dope liquid by an in-line mixer.

[Preparation Method C] A small amount of cellulose ester is added to a solvent and dissolved by stirring. A method in which fine particles are added to this and dispersed by a disperser to prepare a fine particle addition liquid, which is then thoroughly mixed with a dope liquid by an in-line mixer. Preparation method A has excellent dispersibility of silicon dioxide fine particles, and preparation method C
Is excellent in that it is difficult for the silicon dioxide fine particles to re-aggregate,
Among them, the preparation method B is a preferable preparation method because it is excellent in both the dispersibility of the silicon dioxide fine particles and the difficulty of re-aggregation of the silicon dioxide fine particles.

[Dispersion Method] When the fine particles of silicon dioxide are mixed with a solvent and dispersed, the concentration of silicon dioxide is preferably 5 to 30% by mass, more preferably 10 to 25% by mass, and 15 to 20% by mass. % Is most preferred. The higher the dispersion concentration, the more the liquid turbidity with respect to the added amount tends to be low, and the haze and the aggregates are improved, which is preferable.

As the solvent to be used, lower alcohols include preferably methyl alcohol, ethyl alcohol, propyl alcohol, isopropyl alcohol, butyl alcohol and the like. The solvent other than the lower alcohol is not particularly limited, but it is preferable to use the solvent used for forming the cellulose ester film.

Using the dope thus obtained, a cellulose ester film can be produced through the casting process described below.

[Casting Step] The dope prepared in the above step was sent to a press die through a press type quantitative gear pump,
At the casting position, in the step of casting the dope from the pressure die onto the casting support of the endless metal belt or the rotating metal drum that moves indefinitely (hereinafter sometimes simply referred to as a support). is there. The surface of the casting support is a mirror surface.

As another casting method, for example, there is a doctor blade method in which the thickness of the cast dope film is adjusted with a blade, or a method using a reverse roll coater in which the film thickness is adjusted with a counter-rotating roll. However, it is preferable to use a pressure die that can adjust the slit shape of the die and can easily make the film thickness uniform. The pressure die includes, for example, a coat hanger die and a T die, and any of them is preferably used.

In order to increase the film forming speed, two or more pressure dies may be provided on the casting support, and the dope amount may be divided and applied. Alternatively, the inside of the die is divided by slits, and multiple dope solutions with different compositions are cast simultaneously (also called co-casting).
Then, a cellulose ester film having a laminated structure can be obtained.

The dope thus obtained is cast on a support such as a belt or a drum to form a film. In the present invention, the solution casting film formation method using a belt is particularly effective. is there. This is because it is easy to finely adjust the drying conditions on the support as described later. [Solvent Evaporation Step] In this step, the dope is cast on the casting support, and the formed dope film (hereinafter, also referred to as a web) is heated on the casting support to evaporate the solvent. To evaporate the solvent, there are a method of blowing air from the front surface side of the web and / or a method of transferring heat from the back surface of the support to the liquid, a method of transferring heat from the front and back surfaces by radiant heat, and the like. The heating method is preferable in terms of drying efficiency. A method of combining them is also preferable. After casting, the web on the support is preferably dried on the support in an atmosphere of 40 to 100 ° C. In order to maintain the atmosphere at 40 to 100 ° C., it is preferable to apply hot air of this temperature to the upper surface of the web or heat it by means such as infrared rays.

The cellulose ester film according to the present invention preferably peels the web from the support within 30 to 90 seconds after casting. If peeled off in less than 30 seconds, not only the surface quality of the film deteriorates, but also moisture permeability is not preferable. On the contrary, if the drying is performed for more than 90 seconds, the peeling property is deteriorated and the surface quality is deteriorated and the film is strongly curled, which is not preferable.

[Peeling Step] In this step, the web having the solvent evaporated on the support is peeled from the support at the peeling position. The peeled web is sent to the next step. If the amount of residual solvent (the following formula) of the web at the time of peeling is too large,
It is difficult to peel off, or conversely, if it is peeled off after being dried sufficiently on the support, a part of the web may be peeled off on the way.

The temperature at the peeling position on the support is preferably 10 to 40 ° C., more preferably 11 to 30.
℃. The amount of residual solvent in the web at the peeling position is 25
-120 mass% is preferable, More preferably, it is 40-10.
It is 0 mass%. The residual solvent amount of the web according to the present invention,
It is defined by the following formula.

Amount of residual solvent = (mass of web before heat treatment−
Mass after heat treatment of web) / (mass after heat treatment of web) × 100% The heat treatment for measuring the amount of residual solvent is 115 ° C.
Represents that heat treatment is performed for 1 hour. In order to adjust the amount of residual solvent during peeling as described above, the surface temperature of the casting support after casting is controlled so that the organic solvent can be efficiently evaporated from the web. The temperature at the peeling position on the support is preferably set within the above temperature range.
To control the temperature of the support, it is preferable to use a heat transfer method having high heat transfer efficiency, and for example, a back surface heat transfer method using a liquid is preferable.

The heat transfer method using radiant heat or hot air is not a preferable method because it is difficult to control the temperature of the support, but in the belt (support) machine, the temperature control at the place where the belt to be transferred comes to the lower side is performed. In addition, the belt temperature can be adjusted by gentle wind.

The temperature of the support can be partially changed by dividing the heating means, and the temperature of the support varies depending on the casting position, the drying section, the peeling position of the casting support and the like. You can As a method of increasing the film forming speed (the film forming speed can be increased because the film is peeled off while the amount of the residual solvent is as large as possible), there is a gel casting method (gel casting) in which the residual solvent can be peeled off at most. Examples of the gel casting method include a method in which a poor solvent for cellulose ester is added to the dope and gelling is performed after the dope casting, and a method in which the temperature of the support is lowered to cause gelation. There is also a method of adding a metal salt to the dope.

It is possible to accelerate peeling and increase the film-forming speed by gelling on the support to strengthen the film.

In the case of peeling when the amount of residual solvent is larger, if the web is too soft, the flatness is impaired at the time of peeling, and cracks and vertical stripes due to peeling tension are likely to occur, and peeling is performed at a balance between economic speed and quality. The amount of residual solvent is determined. The peeling tension at the time of peeling the support and the film is usually 196 to 245 N / m for peeling, but when wrinkles easily occur at the peeling, it is preferable to peel at 190 N / m or less, and further peeling Lowest tension possible ~ 167N /
m, and then peeling at a minimum tension of 137 N / m is preferable, and particularly preferably at a minimum tension of 100 N / m.
Is to peel off. A lower peel tension is preferable because the in-plane retardation Ro can be kept low. The in-plane retardation Ro is preferably less than 20 nm,
Further, it is preferably less than 10 nm, then less than 5 nm, and most preferably 0 to 1 nm.

In the present invention, the in-plane retardation R
o is three-dimensional refractive index measurement at a wavelength of 590 nm using, for example, an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments Co., Ltd.), and the obtained refractive indexes nx, ny, n
It can be calculated from z. Further, a retardation value R t in the film thickness direction of 0 to 300 nm is obtained, further preferably 0 to 150 nm, more preferably 0 to 70 n.
Those of m are preferably obtained depending on the application. Ro R
t can be calculated by the following formula.

Ro = (nx-ny) × d Rt = [(nx-ny) / 2-nz] × d The cellulose ester film according to the present invention has an angle θ (formed by the slow axis direction and the film forming direction). Radian) and the in-plane retardation Ro have the following relationship, and are particularly preferably used as optical films such as protective films for polarizing plates.

P ≦ 1-sin ² (2θ) sin ² (πRo / λ) P = 0.9999 nx is the refractive index in the slow axis direction in the film plane, and ny is the refraction in the fast axis direction in the film plane. The index, nz, is the refractive index in the thickness direction of the film, and d is the film thickness (nm). θ is the angle (° radian) formed by the slow axis direction in the film plane and the film forming direction (direct direction of the film), and λ is the three-dimensional refractive index measurement for determining the above nx, ny, nz, and θ. The wavelength of light is 590 nm, and π is the circular constant.

[Drying Step] In the drying step, a web is alternately passed through rolls arranged in a staggered manner and conveyed, or a tenter device for holding both ends of the web by clips or pins to convey the web is used. This is a step of drying the web while holding it. The transport tension in the drying step is preferably kept as low as possible in order to keep Ro low, preferably 190 N / m or less, more preferably 170 N / m or less, and further preferably 140 N / m or less, 100 to 130 N / m
Is particularly preferable. In particular, it is effective to maintain the transport tension below the above value until the amount of residual solvent in the film becomes at least 5% by mass or less.

As a drying means, hot air is generally blown on both sides of the web, but a microwave may be applied instead of the air to heat the web. Drying too rapidly
It is easy to damage the flatness of the finished film. Drying at a high temperature is preferably carried out from a residual solvent content of 8% by mass or less. Throughout the whole, the drying temperature is approximately 40 to 250 ° C. It is particularly preferable to dry at 40 to 160 ° C.

In the drying step after peeling from the surface of the casting support, the web tends to shrink in the width direction due to the evaporation of the solvent. Shrinkage increases with rapid drying at high temperature. Drying while suppressing this shrinkage as much as possible is preferable in order to improve the flatness of the finished film. From this viewpoint, for example, JP-A-62-46625.
A method of drying all or part of the drying step while holding the width ends of the web with a clip or pin in the width direction (referred to as a tenter method), among which the clip is used A tenter system and a pin tenter system using a pin are preferably used.

At this time, the stretching ratio in the width direction is 0 to 1.
00% is preferable, and when used as a polarizing plate protective film, 5 to 20% is more preferable, and 8 to 15%.
% Is most preferable, and when used as a retardation film, 10 to 40% is more preferable, and 20 to 30% is most preferable. Ro can be controlled by the draw ratio, and a higher draw ratio is preferable because the flatness of the finished film is excellent. When the tenter is performed, the residual solvent amount of the web is 20 to 10 at the start of the tenter.
The content is preferably 0% by mass, and is preferably dried while applying a tenter until the residual solvent amount of the web becomes 10% by mass or less, more preferably 5% by mass or less.

When the tenter is used, the drying temperature is from 30 to
150 degreeC is preferable, 50-120 degreeC is more preferable,
The most preferable range is 70 to 100 ° C. The lower the drying temperature is, the less evaporation of the ultraviolet absorber, the plasticizer, etc., and the better the process contamination, and the higher the drying temperature, the better the flatness of the film. The ultraviolet absorbers represented by the general formulas [I] and [II] are difficult to evaporate even when the drying temperature is high. Therefore, the effect is remarkable when the tenter drying temperature is high and the production conditions are high. To be demonstrated.

In the film drying step, the film peeled from the support is further dried so that the residual solvent amount is 0.5% by mass or less, more preferably 0.1% by mass or less. , And more preferably 0 to 0.0
It is to be 1 mass% or less.

In the film drying step, generally, a roll suspension method or a method of drying while conveying the film by the pin tenter method as described above is adopted. The means for drying the film is not particularly limited, and generally, hot air, infrared rays, heating rolls, microwaves or the like is used. It is preferable to use hot air for the sake of simplicity. The drying temperature is preferably divided into 3 to 5 stages in the range of 40 to 150 ° C. and gradually increased, and it is more preferable to perform the drying in the range of 80 to 140 ° C. in order to improve dimensional stability.

In the solution casting film forming method, the atmosphere in the drying device may be air in the steps from immediately after casting to drying, but in an atmosphere of an inert gas such as nitrogen gas, carbon dioxide gas or argon. You can go. However, it goes without saying that the danger of the explosion limit of the evaporating solvent in a dry atmosphere must always be taken into consideration.

[Winding Step] This step is a step of winding a dried cellulose ester film after the amount of residual solvent in the web becomes 2% by mass or less.
When the content is 4% by mass or less, a film having good dimensional stability can be obtained.

As a winding method, a generally used winding method may be used, and for example, there are a constant torque method, a constant tension method, a taper tension method, a program tension control method with a constant internal stress, and the like, which are appropriately selected. You can use them properly.

In order to adjust the film thickness, the dope concentration, the amount of the liquid fed by the pump, the slit gap of the die die, the extrusion pressure of the die, the speed of the casting support, etc. are controlled so as to obtain a desired thickness. Good to do. Further, it is preferable to use film thickness detecting means as means for making the film thickness uniform, and feed back programmed feedback information to the above-mentioned respective devices for adjustment.

Although the thickness of the cellulose ester film varies depending on the purpose of use, it is usually in the range of 5 to 500 μm as a finished film, preferably 10 to 250 μm, and more preferably 10 to 250 μm for liquid crystal image display devices. A range of 120 μm is used. The cellulose ester film according to the present invention is particularly 10 to 60 μm.
Although it is a thin film, it has excellent moisture permeability and dimensional stability.

The moisture permeability referred to in the present invention means JIS Z 0.
It is defined by the value measured by the method described in 208. Preferably a moisture permeability 20~250g ^{/ m} 2 · 24 hours, but is preferably in particular 20~200g ^{/ m} 2 · 24 hours. When the moisture vapor permeability exceeds 250 g / m ² · 24 hours, the durability of the polarizing plate is remarkably reduced, and conversely, 20
is less than g / m 2 ^· 24 hours, a solvent such as water which is used in the adhesive during polarizer manufacturing becomes difficult to dry, because the drying time is prolonged, which is not preferable. More preferably 25 to 20
It is 0 g / m ² · 24 hours.

Further, in the cellulose ester film according to the present invention, the dimensional stability can be further improved by reducing the mass change at 80 ° C. and 90% RH.

In the cellulose ester film according to the present invention, it is more preferable that the mass change rate before and after the heat treatment at 80 ° C. and 90% RH for 48 hours is within ± 2%, whereby the moisture permeability is improved. It is possible to obtain a cellulose ester film having an excellent dimensional change rate even though it is a prepared thin film.

The dimensional change rate of the cellulose ester film according to the present invention when heat-treated for 48 hours at 80 ° C. and 90% RH atmosphere is MD direction (film forming direction) and TD direction (film width direction). Direction) ± 0.5%
It is preferably within the range, more preferably within ± 0.3%, further preferably within ± 0.1%, and further preferably within ± 0.05%. The dimensional change rate in the present invention is a characteristic value representing the dimensional change in the longitudinal and lateral directions of the film under severe conditions of temperature and humidity. Specifically, the film is placed under heating conditions, humidification conditions, and hot humidity conditions, and longitudinal and lateral dimensional changes as forced deterioration are measured. For example, with respect to the film sample to be measured, the width direction is 150 mm and the longitudinal direction is 120 mm.
The film is cut into a size, and a cross-shaped mark is made on the film surface with a sharp blade such as a razor at two places at 100 mm intervals in the width direction and the length direction. 23 of the film
Humidity is controlled for 24 hours or more in an environment of 55 ° C. and 55% RH, and the distance L ₁ between the marks in the width direction and the longitudinal direction before processing is measured with a factory microscope. Next, the sample is subjected to a high temperature and high humidity treatment in an electric constant temperature bath (conditions: left in an environment of 80 ° C. and 90% RH for 48 hours). Again, the sample is at 23 ° C., 5
Humidity was adjusted for 24 hours in an environment of 5% RH, and the distance L ₂ between the marks in the width direction and the length direction after processing with a factory microscope was performed.
To measure. The rate of change before and after this process is calculated by the following equation.

Dimensional change rate (%) = (L ₂ −L ₁ ) / L ₁ × 100 Further, the dimensional change rate when treated at 105 ° C. for 5 hours is MD
Direction, TD direction is preferably within ± 0.5%, more preferably within ± 0.3%, further within ±
It is preferably within 0.1%, and further ± 0.05%
It is preferably within the range.

Cellulose ester film according to the present invention
Has a tensile strength of 90 to 170 N / in both MD and TD.
mm^TwoIs preferable, and particularly 120 to 160 N /
mm ^TwoIs preferred. Moisture content is 0.1-5%
Preferably, 0.3-4% is more preferable, 0.5-2%
Is more preferable. Cellulose according to the present invention
Stell film is expected to have a transmittance of 90% or more
More preferably, more preferably 92% or more, still more preferably
It is 93% or more. The haze is 0.5% or less.
It is preferable that it is 0.1% or less.
However, 0% is more preferable.

In the cellulose ester film of the present invention, the curl value is preferably smaller in absolute value,
The deformation direction may be the + direction or the-direction. The absolute value of the curl value is preferably 30 or less, more preferably 20 or less, and particularly preferably 10 or less. The curl value is represented by the radius of curvature (1 / m).

The method for producing the cellulose ester film according to the present invention by the solution casting film forming method will be described in more detail with reference to the drawings.

FIG. 1 is a schematic view showing a preferred example of the solution casting film forming method of a film, and FIG. 1 (a) is a schematic view in the case of drying in a roll conveying / drying process after casting, b)
Is a schematic diagram of the case in which the material is dried in the roll conveying / drying step after casting, and then dried in the tenter conveying / drying step. The same figure (c) is cast, then dried in the tenter conveying / drying step, and then rolled. Schematic diagram when performing drying in the transportation and drying process,
FIG. 6D is a schematic diagram in the case where after the casting, the roll is dried in the roll conveying / drying process, then is dried in the tenter conveying / drying process, and then is dried in the roll conveying / drying process.

In the present invention, the step including the tenter transporting / drying step and the roll transporting / drying step means that the film peeled from the support is dried and wound at any point. A process having a tenter transfer / drying process and a roll transfer / drying process for adjusting the expansion / contraction rate. The tenter transfer / drying process is a process of simultaneously drying while transferring with a tenter transfer device, and adjusting the drying expansion / contraction ratio.The roll transfer / drying process is performed simultaneously with transfer by a roll transfer device, and is dried. The process of adjusting the dry expansion / contraction rate.

In FIG. 1, reference numeral 1 denotes a support which runs endlessly. Mirror-like metal strips are used as the support. Reference numeral 2 denotes a die for casting a dope prepared by dissolving a cellulose ester resin in a solvent on the support 1. 3 indicates a peeling point at which the film on which the dope solidified on the support 1 is solidified is peeled off, and 4 indicates the peeled film. 5
Indicates a tenter conveying / drying process, 51 indicates an exhaust port, and 52 indicates a dry air intake port. The exhaust port 51 and the dry air intake port 52 may be reversed. 6 indicates a tension cutting means. Examples of the tension cutting means include a nip roll and a suction roll. The tension cutting means may be provided at each step. 8 shows a roll conveying / drying process, 81 shows a drying box, 82 shows an exhaust port, and 83 shows a dry air intake port. The exhaust port 82 and the dry air intake 8
It may be the reverse of 3. Reference numeral 84 indicates an upper conveyance roll, and 85 indicates a lower conveyance roll. The transport roll 8
The upper and lower sets 4 and 85 are composed of a plurality of sets.
Reference numeral 7 represents a rolled film.

In the step shown in FIG. 1D, the roll transfer / drying step before the tenter transfer / drying step 5 is performed first.
It is called a one-roll transfer / drying process, and the roll transfer / drying process after the tenter transfer / drying process 5 is called a second roll transfer / drying process. It should be noted that a cooling step not shown in FIGS. 1A to 1D may be provided as necessary before winding.

In the present invention, the cellulose ester film may be produced by any of the above solution casting film forming methods.

The cellulose ester film according to the present invention is a member for liquid crystal display because of its good moisture permeability and dimensional stability.
Specifically, it is preferably used for a protective film for polarizing plate. In particular, the cellulose ester film according to the present invention is preferably used in a protective film for a polarizing plate, which has severe requirements for both moisture permeability and dimensional stability.

The polarizing plate according to the present invention can be manufactured by a general method. For example, there is a method of laminating an optical film or a cellulose ester film with an alkali saponification treatment, dipping the polyvinyl alcohol film in an iodine solution, and stretching the polarizing film on both sides, using a completely saponified polyvinyl alcohol aqueous solution. . The alkali saponification treatment refers to a treatment in which the cellulose ester film is immersed in a high temperature strong alkaline solution in order to improve the wettability of the water-based adhesive and improve the adhesiveness.

The cellulose ester film of the present invention comprises a hard coat layer, an antiglare layer, an antireflection layer, an antifouling layer,
Various functional layers such as an antistatic layer, a conductive layer, an optically anisotropic layer, a liquid crystal layer, an alignment layer, an adhesive layer, an adhesive layer and an undercoat layer can be provided. These functional layers can be provided by a method such as coating or vapor deposition, sputtering, plasma CVD, atmospheric pressure plasma treatment and the like.

The polarizing plate thus obtained is provided on one side or both sides of the liquid crystal cell, and by using this, the liquid crystal display device of the present invention is obtained.

By using the protective film for a polarizing plate made of the cellulose ester film according to the present invention, it is possible to provide a polarizing plate excellent in durability, dimensional stability and optical isotropy as well as thinning. Furthermore, a liquid crystal display device using the polarizing plate or retardation film of the present invention,
It is possible to maintain stable display performance for a long period of time. The cellulose ester film according to the present invention can also be used as a base material for an antireflection film or an optical compensation film.

Specific examples will be described below, but the present invention is not limited thereto.

[0128]

[Example] [Example 1] 50 ml of methyl isobutyl ketone was added to a 1 L flask equipped with a stirrer, a thermometer, and a reflux condenser.
L, methyl cellosolve 50 mL, 2- (2 ′, 4′-dihydroxyphenyl) -5-chlorobenzotriazole 52.4 g, potassium iodide 1.0 g, dimethylformamide 1.0 g, potassium carbonate 20.7 g, 1-bromo 2-Octyldodecane (101.2 g) was added, the temperature was raised to 100 ° C. with stirring, and the mixture was reacted at this temperature for 24 hours. After the reaction was completed, the temperature was cooled to 60 ° C, and the toluene was 200 m.
After adding L and 100 mL of water, the pH was adjusted to about 2 with 75% sulfuric acid, and the lower layer was separated. The upper layer was washed twice with 50 mL of water, concentrated by an evaporator, and the obtained oil was crystallized with 300 mL of isopropyl alcohol to give 2- {2′-hydroxy-4 ′-(2-octyl) according to the present invention. Dodecyl) oxyphenyl} -5-chlorobenzotriazole (in the general formula [I], R ₁ = Cl, R ₂ = R
₃ = R ₄ = H, R ₅ = C ₁₀ H ₂₁ , R ₆ = C
50.9 g of ₈ H ₁₇ ) was obtained.

The melting point of this compound was measured and found to be 3
4 to 35 ° C., and this compound was confirmed to have the above UV-I-
It was confirmed to have a structure represented by 6. Furthermore, when measured with a spectrophotometer, λmax is 35
It was 4.5 nm (chloroform soln.).

[Example 2] In Example 1, 1-bromo-2- was used instead of 1-bromo-2-octyldodecane.
The procedure of Example 1 was repeated except that 85.5 g of hexyldecane was used.

As a result, 2- {2'-hydroxy-4 '-(2-hexyldecyl) oxyphenyl} -5-chlorobenzotriazole according to the present invention (in the general formula [I], R ₁ = Cl, R ₂ = R ₃ = R ₄ = H, R ₅ = C
_{8 H 17, R 6 = C} 6 H 13) was obtained 53.4 g.

When the melting point of this compound was measured, it was found to be 4
The compound was 3 to 44 ° C., and the compound was found to have the above-mentioned UV-I-
It was confirmed to have a structure represented by 4. Furthermore, when measured with a spectrophotometer, λmax is 35
It was 4.5 nm (chloroform soln.).

Example 3 Methyl ethyl ketone 14 m
2- (2 ', 4'- in 6 mL of L, methyl cellosolve
10.47 g of dihydroxyphenyl) -5-chlorobenzotriazole and 2-hexyldecyl-bromide 1
4.66 g, sodium carbonate 2.76 g, potassium iodide 0.2 g, and dimethylformamide 0.4 g were added at room temperature, and the temperature was gradually raised to 90 ° C. over 1 hour. afterwards,
The reaction was continued for 3 hours. Then, the temperature was gradually raised while removing the solvent, and after 7 hours, the temperature was raised to 130 ° C. After cooling, 80 mL of toluene and dilute sulfuric acid were added to separate the layers. The toluene phase was washed with water and then concentrated under reduced pressure. The residue is purified by silica gel chromatography using toluene / ethyl acetate as a developing solution to give 2- {2'-hydroxy-4'- according to the present invention.
(2-hexyldecyl) oxyphenyl} -5-chlorobenzotriazole (in the general formula [I], R ₁ ═C
l, R ₂ = R ₃ = R ₄ = H, R ₅ = C ₈ H ₁₇ , R ₆ =
C ₆ H ₁₃₎ was obtained 10.66 g.

When the melting point of this compound was measured, the melting point was 4
The compound was 3 to 44 ° C., and the compound was found to have the above-mentioned UV-I-
It was confirmed to have a structure represented by 4. Furthermore, when measured with a spectrophotometer, λmax is 35
It was 4.5 nm (chloroform soln.).

[Embodiment 4] Sample No. 1 was manufactured by the method described below. 1-No. 12 optical films were produced.

[Preparation of Silicon Oxide Dispersion] Aerosil 200V (manufactured by Nippon Aerosil Co., Ltd., average particle diameter of primary particles: 12 nm, apparent specific gravity: 100 g / L) 10 parts by mass Ethanol 90 parts by mass or more by stirring with a dissolver for 30 minutes. After that, dispersion was performed with Manton-Gorin. Liquid turbidity after dispersion is 93 pp
It was m.

[Preparation of In-Line Additive Liquid A] UV Absorber (Compounds shown in Table 1 below) 10 parts by mass Cellulose triacetate synthesized from linter cotton 4 parts by mass Methylene chloride 100 parts by mass or more are charged into a closed container. While heating and stirring, the solution was completely dissolved and then filtered. In addition to this, the above-mentioned silicon oxide dispersion liquid 1
After adding 2 parts by mass with stirring and further stirring for 30 minutes, polypropylene wind cartridge filter TCW-PPS (10N, 2) manufactured by Advantech Toyo Corp.
The in-line additive liquid A was prepared by filtering with 0N and increasing the filtration accuracy one by one.

[Preparation of Dope Liquid A] Cellulose triacetate synthesized from linter cotton 85 parts by mass Cellulose triacetate synthesized from wood pulp 15 parts by mass Triphenyl phosphate 11.5 parts by mass Methylene chloride 475 parts by mass Ethanol 50 parts by mass The above was put into a closed container, completely dissolved while heating and stirring, and Azumi Filter Paper No. No. manufactured by Azumi Filter Paper Co., Ltd. A dope solution A was prepared by filtration using 244.

[Film Forming] FineMet NF manufactured by Nippon Seisen Co., Ltd. (absolute filtration accuracy 50 μm) in the film forming line.
m, 15 μm, 5 μm in this order with increasing filtration accuracy). On the other hand, in the in-line additive liquid line, Finemet NF manufactured by Nippon Seisen Co., Ltd.
The in-line additive liquid A was filtered by (absolute filtration accuracy of 50 μm, 15 μm, 5 μm in this order with increasing filtration accuracy).

2.2 parts by mass of the filtered in-line additive liquid A was added to 100 parts by mass of the filtered dope liquid A, and the resulting mixture was sufficiently mixed with an in-line mixer (Toray Co., Ltd. static in-tube mixer Hi-Mixer SWJ). Then, using a belt casting device, it was uniformly cast on a stainless band support at a temperature of 33 ° C. and a width of 1500 mm. The solvent was evaporated on the stainless steel band support until the residual solvent amount became 80%, and the film was peeled off from the stainless steel band support with a peeling tension of 127 N (13 kgf) / m. The peeled cellulose triacetate film was slit into a width of 1550 mm and then stretched by 10% in the width direction with a tenter,
Dry at a drying temperature of 0 ° C, then 120 ° C, 135 ° C
Of the cellulose triacetate film sample No. 1 by terminating the film at a width of 1330 mm and knurling the film at both ends with a width of 10 mm and a height of 5 μm. 1 to N
o. 12 optical films were obtained. The film thickness of each sample is 40μ
m, and the number of turns was 2000 m. Incidentally, No. No. 12 optical film was not stretched with a tenter.

Table-1 Optical film number Ultraviolet absorber of in-line additive liquid A Presence or absence of tenter No. 1 UV-II-1 Yes No. 2 UV-II-2 Yes No. 3 UV-II-4 Yes No. 4 UV-I-7 Yes No. 5 UV-I-4 Yes No. 6 UV-I-6 Yes No. 7 UV-I-1 Yes No. 8 UV-I-2 Yes No. 9 UV-I-10 Yes No. 10 UV-I-11 Yes No. 11 UV-C1 ^* Yes No. 12 UV-C1 ^* None * UV-C1 [Evaluation of Characteristics of Optical Film Sample] Each of the samples prepared as described above was subjected to the following evaluations.

[Measurement of Evaporation Amount of UV Absorber] Each sample 3
0 g was cut into small pieces, and methyl ethyl ketone 100 was added to it.
g was added and ultrasonic irradiation was performed to extract the ultraviolet absorber. Then, after filtration, the solvent is evaporated to dryness, an internal standard sample is added, and the gas chromatograph mass spectrometry system (GC
/ MS) of the ultraviolet absorber. The reduction in the quantitative value of the sample was calculated with respect to the prescribed value obtained from the calculation, and the ranking was performed as follows. It should be noted that the smaller the difference from the prescribed value is, the less the transpiration of the ultraviolet absorber is and the better. A: Reduction amount less than 1% B: Reduction amount 1% or more and less than 3% C: Reduction amount 3% or more

[Evaluation of Roll Contamination] After producing a 10,000 m cellulose ester film, the degree of soiling of the first roll contacting the film peeled from the stainless steel band support was visually observed according to the evaluation criteria described below. . A: No stain on the roll is observed B: The roll is slightly soiled C: The roll is completely soiled A to B are the levels at which production can be continued However, it was judged that C was at a level where the production was interrupted and the roll was cleaned.

[Evaluation of Pushing Failure] At the time when a 10,000 m cellulose ester film was prepared, a film sample was sampled and the number of pressing failures of 30 μm or more existing on 1 m ^{2 of the} obtained film was measured.

[Evaluation of surface property] A fluorescent lamp which was lit was reflected on the surface of the sample and reflected, and the distortion or fine disorder was observed, and the flatness was ranked according to the following levels. A: Fluorescent lamp looks straight B: Fluorescent lamp looks partially bent C: Fluorescent lamp looks like mottle

[Evaluation of Light Resistance] According to the method described below.
After performing alkali saponification treatment on each sample, make a polarizing plate.
Parallel transmittance (H₀) And orthogonal transmittance
(H₉₀) Was measured and the degree of polarization was calculated according to the following formula.
After that, attach each polarizing plate to the sunshine weather meter.
Forced for 200 hours without UV cut filter
After deterioration treatment, parallel transmittance after deterioration treatment
(H₀′) And the orthogonal transmittance (H₉₀’) Is measured and
Therefore, the polarization degree P₀, P₅₀₀To calculate the change in polarization degree
It was calculated by the following formula. Polarization degree P₀= [(H₀-H₉₀) / (H₀+ H₉₀)]
^1/2× 100 Polarization degree P₅₀₀= [(H₀’-H₉₀’) / (H₀’+
H₉₀’)]^1/2× 100 Polarization change = P₀-P₅₀₀ The rate of change in the degree of polarization obtained as described above is
I divided the links. ⊚: Polarization degree change rate less than 10% ◯: Polarization degree change rate of 10% or more and less than 25% X: Polarization degree change rate of 25% or more

[Alkali Saponification Treatment] Saponification step: 2 mol / L NaOH 50 ° C. 90 seconds Water washing step: Water 30 ° C. 45 seconds Neutralization step: 10 mass% HCl 30 ° C. 45 seconds Water washing step: Water 30 ° C. 45 seconds The above conditions Each sample was subjected to saponification, water washing, neutralization and water washing in this order, and then dried at 80 ° C.

[Production of Polarizing Plate] A polyvinyl alcohol film having a thickness of 120 μm was used, and 1 kg of iodine and 4 kg of boric acid were used.
Was dipped in 100 kg of an aqueous solution containing, and stretched 6 times at 50 ° C. to form a polarizing film. The alkali-saponified sample was bonded to both surfaces of this polarizing film using a fully saponified polyvinyl alcohol 5% aqueous solution as an adhesive to prepare a polarizing plate.

Table 2 shows the evaluation results obtained as described above.

[0150]                                 Table-2 Optical fill Process evaluation Evaluation of optical film characteristics   Number Evaporation Rank Roll Dirt Pressed Failure Surface Surface Light Resistance No. 1 A A 5 A ◎ The present invention No. 2 A A 3 A ◎ The present invention No. 3 A A 1 A ◎ The present invention No. 4 A A 1 A ◎ The present invention No. 5 A A 0 A ◎ The present invention No. 6 A A 0 A ◎ The present invention No. 7 A A 1 A ◎ The present invention No. 8 A A 0 A ◎ The present invention No. 9 A A 1 A ◎ The present invention No. 10 A A 0 A ◎ The present invention No. 11 B C 156 A × outside the invention No. 12 B C 155 C × outside the invention

As is clear from Table 2, the samples of the present invention containing the ultraviolet absorbers represented by the general formulas [I] and [II] are different from the samples of the present invention in the film formation. It can be seen that the evaporation of the ultraviolet absorber is small, the occurrence of roll stains and pushing failures is reduced, and the surface uniformity and light resistance are excellent.

[Embodiment 5] Sample No. 21-No. 32 optical films were produced.

[Preparation of In-Line Additive Liquid B] Ultraviolet Absorber (Compounds in Table 3 below) 10 parts by mass Acetyl substitution degree 1.95, propionyl substitution degree 0.7, number average molecular weight 75000 cellulose acetate pro 4 parts by mass of pionate 100 parts by mass or more of methyl acetate were placed in a closed container, completely dissolved while heating and stirring, and then filtered. To this, 12 parts by mass of the silicon oxide dispersion liquid prepared in Example 4 was added with stirring, and further 3 parts were added.
After stirring for 0 minutes, Advantech Toyo Co., Ltd. polypropylene wind cartridge filter TCW-PP
The in-line additive liquid B was prepared by filtering with S (10N, 20N, which was used after sequentially increasing the filtration accuracy).

[Preparation of Dope Liquid B] Cellulose acetate propionate having an acetyl substitution degree of 1.95, a propionyl substitution degree of 0.7, and a number average molecular weight of 7500 100 parts by mass triphenyl phosphate 11.5 parts by mass methyl acetate 300 Parts by mass Ethanol 80 parts by mass or more is put into a closed container, completely dissolved while heating and stirring, and Azumi Filter Paper No. No. manufactured by Azumi Filter Paper Co., Ltd. A dope solution B was prepared by filtration using 244.

[Film Forming] In the film forming line, Finemet NF manufactured by Nippon Seisen Co., Ltd. (absolute filtration accuracy 50 μ
m, 15 μm, 5 μm in this order with increasing filtration accuracy). On the other hand, in the in-line additive liquid line, Finemet NF manufactured by Nippon Seisen Co., Ltd.
The in-line additive liquid B was filtered by (absolute filtration accuracy of 50 μm, 15 μm, 5 μm in this order with increasing filtration accuracy).

2.2 parts by mass of the filtered in-line additive liquid B was added to 100 parts by mass of the filtered dope liquid B, and the mixture was sufficiently mixed with an in-line mixer (Toray's static in-tube mixer Hi-Mixer SWJ). Then, using a belt casting device, it was uniformly cast on a stainless band support at a temperature of 33 ° C. and a width of 1500 mm. The solvent was evaporated on the stainless steel band support until the residual solvent amount became 80%, and the film was peeled off from the stainless steel band support with a peeling tension of 127 N (13 kgf) / m. The peeled cellulose triacetate film was slit into a width of 1550 mm and then stretched in the width direction by 25% with a tenter,
Dry at a drying temperature of 0 ° C, then 120 ° C, 135 ° C
Of the cellulose triacetate film, sample No. 1 of the cellulose triacetate film was dried by terminating the drying while transporting the drying zone with a large number of rolls, slitting to a width of 1330 mm, and knurling the both ends of the film with a width of 10 mm and a height of 5 μm. 21-N
o. 32 optical films were obtained. The film thickness of each sample is 40μ
m, and the number of turns was 2000 m. Incidentally, No. No. 32 optical film was not stretched with a tenter.

[0157]                               Table-3 Optical film number UV absorber for in-line additive liquid B With or without tenter No. 21 UV-II-1 Yes No. 22 UV-II-2 Yes No. 23 UV-II-4 Yes No. 24 UV-I-7 Yes No. 25 UV-I-4 Yes No. 26 UV-I-6 Yes No. 27 UV-I-1 Yes No. 28 UV-I-2 Yes No. 29 UV-I-10 Yes No. 30 UV-I-11 Yes No. 31 UV-C1 Yes No. 32 UV-C1 None

[Evaluation of Characteristics of Optical Film Sample] For each of the samples prepared as described above, the amount of transpiration of the ultraviolet absorber was measured, roll stain was evaluated, and pressed according to the method described in Example 4. Since the evaluation of failure, the evaluation of surface property, and the evaluation of light resistance were performed, the results are shown in Table-4. Table-4 Optical fill process Appropriate evaluation Optical film characteristic number No. Evaporation rank Roll stain Pressed failure Surface property Light resistance No. 21 A A 6 A ◎ The present invention No. 22 A A 4 A ◎ The present invention No. 23 A A 2 A ◎ The present invention No. 24 A A 2 A ◎ The present invention No. 25 A A 1 A ◎ The present invention No. 26 A A 0 A ◎ The present invention No. 27 A A 2 A ◎ Present invention No. 28 A A 1 A ◎ The present invention No. 29 A A 1 A ◎ Present invention No. 30 A A 0 A ◎ The present invention No. 31 C C 254 A × Non-invention No. 32 B C 248 C × As is clear from Table 4 of the invention, the sample of the present invention containing the ultraviolet absorber represented by the general formulas [I] and [II] is Evaporation of the ultraviolet absorber during film formation is small, and the occurrence of roll contamination and pushing failures is reduced, and
It can be seen that the surface uniformity and light resistance are excellent.

[Embodiment 6] A commercially available liquid crystal display panel (NE
Color liquid crystal display made by company C MultiSync
The polarizing plate on the outermost surface of LCD1525J model name LA-1529HM) was carefully peeled off, and the polarizing plates prepared in Examples 4 and 5 were stuck together with their polarization directions aligned.

The contrast of each liquid crystal display panel was visually evaluated. As a result, the liquid crystal display panel using the polarizing plate of the present invention was used for a long period of time as compared with the liquid crystal display panel using the polarizing plate of the comparative example. It was confirmed that the high contrast was maintained.

[0161]

The benzotriazole according to the present invention has a low melting point, low volatility, and excellent compatibility with resins.
Bleed out is unlikely to occur, and it has an excellent ultraviolet absorbing effect.

The optical film of the present invention is excellent in light resistance and surface property, has no process contamination, and has features such as reduction of roll stains and pushing failures.

The polarizing plate and the display device using the optical film according to the present invention have features such as high contrast over a long period of time.

[Brief description of drawings]

[Figure 1] Schematic diagram of the solution casting method of film

[Explanation of symbols]

1 Mirror-like strip metal casting support 2 dice 4 Cellulose ester film 5 Tenter transfer and drying process 6 Tension cutting means 8-roll transfer / drying process 84 Upper transport roll 85 Lower transport roll

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C09K 3/00 104 C09K 3/00 104C 4J002 G02B 5/22 G02B 5/22 5/30 5/30 G02F 1 / 1335 510 G02F 1/1335 510 // B29L 7:00 B29L 7:00 (72) Inventor Osamu Ishige 1 Sakura-cho, Hino-shi, Tokyo Konica Co., Ltd. (72) Inventor Kaori Ohno Sakura-cho, Hino-shi, Tokyo No. 1 Konica Stock Company (72) Inventor Masayuki Nishimatsu 1-3-3 Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Within Kemipro Kasei Co., Ltd. 3-3 Chemi Kasei Co., Ltd. (72) Inventor Yoshinori Omae 1-3-3 Higashikawasaki-cho, Chuo-ku, Kobe-shi, Hyogo Pro-Kasei Co., Ltd. F-term (reference) 2H048 CA04 CA09 CA13 CA19 CA23 CA24 CA25 CA26 CA27 2H049 BB13 BB33 BB51 BB65 BB67 BC09 BC14 BC22 2H091 FA08X FA08Z FB02 LA02 LA03 LA04 LA12 4F071 AA09 AC19 AE05 BB07 AB01 AB01 AB02 AB01 BB02 AB01 BB02 BC01 CA02 GC07 GE24 4J002 AB021 EU176 FD056 GP00

Claims (10)

[Claims] 1. A benzotriazole represented by the following general formula [I]: General formula [I] [In the general formula [I], R _{1 to} R ₄ are hydrogen atoms, halogen atoms, or linear (or branched) alkyl groups (or alkoxy groups) having 1 to 8 carbon atoms, and R ₅ and R ₆ are Carbon number 1
24 straight chain (or branched) alkyl groups. However, R
The sum of the carbon number of _{5 and} the carbon number of R ₆ is 11 or more. ] 2. A benzotriazole represented by the following general formula [I]: General formula [I] [In the general formula [I], R _{1 to} R ₄ are hydrogen atoms, halogen atoms, or linear (or branched) alkyl groups (or alkoxy groups) having 1 to 8 carbon atoms, and R ₅ and R ₆ are 6-carbon
10 straight-chain alkyl groups. ] 3. An ultraviolet absorber comprising the benzotriazole according to claim 1 or 2 as an active ingredient. 4. The following general formula [I] or general formula [II]
An optical film comprising a compound represented by: General formula [I] [In the general formula [I], R _{1 to} R ₄ are hydrogen atoms, halogen atoms, or linear (or branched) alkyl groups (or alkoxy groups) having 1 to 8 carbon atoms, and R ₅ and R ₆ are Carbon number 1
24 straight chain (or branched) alkyl groups. However, R
The sum of the carbon number of _{5 and} the carbon number of R ₆ is 11 or more. ] General formula [II] [In the general formula [II], X is a halogen atom, Y is a branched alkyl group having 10 to 26 carbon atoms, and R ₂ , R ₃ ,
R ₄ is a hydrogen atom or an alkyl group which may have a substituent. ] 5. The following general formula [I] or general formula [II]
An optical film comprising a compound represented by and a cellulose ester. General formula [I] [In the general formula [I], R _{1 to} R ₄ are hydrogen atoms, halogen atoms, or linear (or branched) alkyl groups (or alkoxy groups) having 1 to 8 carbon atoms, and R ₅ and R ₆ are Carbon number 1
24 straight chain (or branched) alkyl groups. However, R
The sum of the carbon number of _{5 and} the carbon number of R ₆ is 11 or more. ] General formula [II] [In the general formula [II], X is a halogen atom, Y is a branched alkyl group having 10 to 26 carbon atoms, and R ₂ , R ₃ ,
R ₄ is a hydrogen atom or an alkyl group which may have a substituent. ] 6. A method for producing an optical film using a solution casting method, comprising the following general formula [I] or general formula [I
The resin solution containing the compound represented by the formula [I] is cast on a support, dried and peeled off, and 0-10 in the width direction by a tenter.
A method for producing an optical film, which comprises stretching 0%. General formula [I] [In the general formula [I], R _{1 to} R ₄ are hydrogen atoms, halogen atoms, or linear (or branched) alkyl groups (or alkoxy groups) having 1 to 8 carbon atoms, and R ₅ and R ₆ are Carbon number 1
24 straight chain (or branched) alkyl groups. However, R
The sum of the carbon number of _{5 and} the carbon number of R ₆ is 11 or more. ] General formula [II] [In the general formula [II], X is a halogen atom, Y is a branched alkyl group having 10 to 26 carbon atoms, and R ₂ , R ₃ ,
R ₄ is a hydrogen atom or an alkyl group which may have a substituent. ] 7. The method for producing an optical film according to claim 6, wherein a resin solution containing methyl acetate and a compound represented by the general formula [I] or the general formula [II] is used. 8. An optical film produced by the method for producing an optical film according to claim 6 or 7. 9. A polarizing plate comprising the optical film according to claim 4, claim 5, or claim 8. 10. A display device using the optical film according to claim 4, claim 5, or claim 8.