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WO2013114450A1 - Film de compensation optique et procédé de fabrication associé, plaque polarisante et dispositif d'affichage à cristaux liquides - Google Patents

Film de compensation optique et procédé de fabrication associé, plaque polarisante et dispositif d'affichage à cristaux liquides Download PDF

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Publication number
WO2013114450A1
WO2013114450A1 PCT/JP2012/000643 JP2012000643W WO2013114450A1 WO 2013114450 A1 WO2013114450 A1 WO 2013114450A1 JP 2012000643 W JP2012000643 W JP 2012000643W WO 2013114450 A1 WO2013114450 A1 WO 2013114450A1
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WIPO (PCT)
Prior art keywords
optical compensation
compensation film
liquid crystal
cellulose acetate
film
Prior art date
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PCT/JP2012/000643
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English (en)
Japanese (ja)
Inventor
佐藤　英幸
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Konica Minolta Inc
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Konica Minolta Inc
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Priority to PCT/JP2012/000643 priority Critical patent/WO2013114450A1/fr
Priority to KR1020130010605A priority patent/KR101291497B1/ko
Priority to CN201310035263.1A priority patent/CN103064143B/zh
Publication of WO2013114450A1 publication Critical patent/WO2013114450A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • G02B5/3041—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
    • G02B5/305—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
    • C08L1/08—Cellulose derivatives
    • C08L1/10—Esters of organic acids, i.e. acylates
    • C08L1/12—Cellulose acetate
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/13363—Birefringent elements, e.g. for optical compensation
    • G02F1/133635—Multifunctional compensators

Definitions

  • the present invention relates to an optical compensation film, a manufacturing method thereof, a polarizing plate, and a liquid crystal display device.
  • Liquid crystal display devices are widely used as liquid crystal displays for televisions and personal computers. Among them, a vertical alignment type liquid crystal display device is preferably used because of its high contrast. These vertical alignment type liquid crystal display devices are required to further improve the front contrast.
  • the liquid crystal display device usually has a liquid crystal cell and a polarizing plate sandwiching it.
  • the polarizing plate has a polarizer and a protective film that sandwiches the polarizer.
  • An optical compensation film is usually used for the protective film disposed on the liquid crystal cell side of the polarizer. And in order to raise the front contrast of a liquid crystal display device, reducing scattering factors, such as an internal haze of an optical compensation film, is examined.
  • Patent Document 1 proposes an optical compensation film with reduced anisotropic scattering.
  • Anisotropic scattering is expressed as the difference between the scattered light intensity in the slow axis direction of the optical compensation film and the scattered light intensity in the direction orthogonal thereto.
  • a film containing a cellulose ester is often used because it is easily bonded to a polarizer.
  • cellulose acetate (cellulose diacetate) having a substitution degree of acetyl group of 2.5 or less is not only inexpensive, but can develop a high retardation by stretching a film containing the cellulose acetate. Therefore, an optical compensation film containing cellulose diacetate has been studied.
  • the vertical alignment type liquid crystal display device having an optical compensation film containing cellulose diacetate has a problem that the contrast in the oblique direction is significantly lower than the contrast in the front direction, and unevenness in contrast due to the viewing angle tends to occur. It was. Contrast unevenness due to viewing angle was likely to occur even when an optical compensation film having sufficiently reduced internal haze was used.
  • the present invention has been made in view of the above circumstances, and an object thereof is to provide an optical compensation film containing cellulose diacetate and capable of reducing unevenness in contrast due to the viewing angle of a display device.
  • the content of the glass transition temperature reducing agent is different from the content of the glass transition temperature reducing agent in the vicinity of the other surface, and the optical compensation film has a wavelength of 550 nm parallel to the normal of the optical compensation film surface.
  • An optical compensation film in which the ratio of the transmitted scattered light intensity in the range of 4 to 60 ° to the integrated amount I 4-60 is 97% or more.
  • the retention time is 0 to 28 minutes with a peak area in the range of 0 to 4 minutes.
  • the content of the glass transition temperature reducing agent in the vicinity of one surface of the optical compensation film is 1.1 times the content of the glass transition temperature reducing agent in the vicinity of the other surface of the optical compensation film.
  • the optical compensation film according to any one of [1] to [4], which is 1.5 times or more and 1.5 times or less.
  • the in-plane retardation R 0 defined by the following formula (I) and measured under the conditions of a wavelength of 590 nm and 23 ° C. and 55% RH is 10 nm or more and 100 nm or less.
  • nx represents the refractive index in the slow axis direction x at which the refractive index is maximum in the in-plane direction of the optical compensation film
  • ny represents the refractive index in the direction y perpendicular to the slow axis direction x in the in-plane direction of the optical compensation film
  • nz represents the refractive index in the thickness direction z of the optical compensation film
  • t (nm) represents the thickness of the optical compensation film
  • a polarizing plate comprising the optical compensation film according to any one of [1] to [6].
  • a liquid crystal cell a first polarizing plate disposed on one surface of the liquid crystal cell and including a first polarizer, and a second polarizer disposed on the other surface of the liquid crystal cell. And a second polarizing plate, wherein at least one of the first polarizing plate and the second polarizing plate comprises the optical compensation film according to any one of [1] to [6].
  • the liquid crystal cell includes a pair of transparent substrates and a liquid crystal layer that is disposed between the pair of transparent substrates and includes liquid crystal molecules. When no voltage is applied, the liquid crystal cells are disposed on the pair of transparent substrates.
  • the optical compensation film of the present invention contains cellulose diacetate and can reduce unevenness in contrast due to the viewing angle of the display device of the liquid crystal display device.
  • AAA cellulose acetate
  • a ' cellulose acetate
  • the optical compensation film of the present invention contains a cellulose ester and may further contain additives such as a glass transition temperature lowering agent as necessary.
  • the optical compensation film of the present invention is disposed between a liquid crystal cell of a liquid crystal display device and a polarizer, and is preferably used as a polarizing plate protective film having a phase difference adjusting function, for example.
  • Cellulose ester is a compound obtained by esterifying a hydroxyl group of cellulose with an aliphatic carboxylic acid or an aromatic carboxylic acid.
  • the acyl group contained in the cellulose ester is an aliphatic acyl group or an aromatic acyl group, preferably an aliphatic acyl group.
  • an aliphatic acyl group having 2 to 6 carbon atoms is preferable, and an aliphatic acyl group having 2 to 4 carbon atoms is more preferable.
  • Examples of the aliphatic acyl group having 2 to 4 carbon atoms include an acetyl group, a propionyl group, a butanoyl group, and the like, more preferably an acetyl group.
  • cellulose ester examples include cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, cellulose acetate butyrate, and the like, preferably cellulose acetate.
  • cellulose acetate it is preferable that all of the acyl groups contained in the cellulose ester are acetyl groups.
  • Cellulose acetate has an average degree of acetyl group substitution (acyl group total substitution degree) that it is easy to develop a phase difference by stretching, a high phase difference can be obtained even if the film thickness is reduced, and a high phase difference is developed. Therefore, the stretching ratio is preferably 2.0 to 2.5, more preferably 2.2 to 2.5, and still more preferably 2.3 to 2.48.
  • the method for measuring the total degree of acyl group substitution can be measured according to ASTM-D817-96.
  • Cellulose acetate has an acetyl group substitution degree of 2.2 to 2.5 in order to increase I 4-10 / I 4-60 of the optical compensation film described later (to concentrate transmitted scattered light in the front direction).
  • a mixture of cellulose acetate A and cellulose acetate B (low substitution degree component) having an acetyl group substitution degree of less than 2.2 is preferable.
  • the content of the low substitution component in the mixture is preferably 0.1% by mass or more, and more preferably 1.0% by mass or more with respect to the entire mixture.
  • the content of the low substitution degree component is less than 0.1% by mass, scattering of the transmitted light of the optical compensation film occurs not only in the front direction but also in an oblique direction (transmitted scattered light is difficult to concentrate in the front direction). Therefore, unevenness in contrast tends to occur between the front direction and the oblique direction of the display device.
  • the content of the low substitution degree component is preferably 10% by mass or less, and more preferably 5% by mass or less with respect to the entire mixture. When the content of the low substitution degree component is more than 10% by mass, the optical compensation film becomes cloudy, so that the transparency as the protective film is easily impaired.
  • the low substitution component can be confirmed as a peak having a retention time of 0 to 4 minutes when measured by high performance liquid chromatography (HPLC) under the following conditions.
  • HPLC high performance liquid chromatography
  • Apparatus Waters Alliance type 2695 system
  • Column Silica gel filler (carbon load ratio: 4.6%, bonding functional group: phenyl group, end cap: yes, shape: spherical, average particle size: 4 ⁇ m, pore size: 60 mm , surface area: 120m 2 / g) column having an inner diameter 3.9 mm ⁇ length 150mm comprising (Waters Ltd.
  • the ratio of the peak area having a retention time of 0 to 4 minutes to the total peak area having a retention time of 0 to 28 minutes may be 0.1% or more. Preferably, it is 1% or more.
  • the ratio is less than 0.1% by mass, scattering of the transmitted light of the optical compensation film occurs not only in the front direction but also in an oblique direction (transmitted scattered light is less likely to be concentrated in the front direction). Contrast unevenness tends to occur between the front direction and the diagonal direction.
  • the ratio of the peak area having a retention time of 0 to 4 minutes to the total peak area having a retention time of 0 to 28 minutes is preferably 10% or less, more preferably 5% or less. preferable. When the ratio is more than 10%, the optical compensation film becomes cloudy, and the transparency as the protective film is likely to be impaired.
  • a mixture of cellulose acetate A having an acetyl group substitution degree of 2.2 to 2.5 and cellulose acetate B (low substitution degree component) having an acetyl group substitution degree of less than 2.2 adjusts the synthesis conditions of cellulose acetate.
  • a mixture of cellulose diacetate (purified cellulose diacetate) containing no low substitution degree and a predetermined amount of a low substitution degree component is a mixture of cellulose diacetate (purified cellulose diacetate) containing no low substitution degree and a predetermined amount of a low substitution degree component.
  • the synthesis of cellulose acetate usually involves (A) activation step (pretreatment step), (B) acetylation step, (C) acetylation reaction termination step, (D) aging step (hydrolysis step), and (E) A maturing stop step is included.
  • content of the low substitution degree component in the cellulose acetate obtained can be adjusted by adjusting the conditions of the ripening stop process of (E).
  • Cellulose acetate containing no low-substituted formed for example, cellulose acetate X 0 obtained by the synthesis, after the dispersion solution was dispersed in a low degree of substitution component good solvent (preferably methanol) The obtained dispersion solution can be filtered to obtain a filtered product.
  • the low substitution degree component can be obtained by concentrating and drying the filtrate.
  • the number average molecular weight of cellulose acetate is preferably 3.0 ⁇ 10 4 or more and less than 7.0 ⁇ 10 4 , and 4.5 ⁇ 10 4 or more and 6.0. More preferably, it is less than ⁇ 10 4 .
  • the weight average molecular weight of the cellulose acetate is preferably less than 1.1 ⁇ 10 5 or more 2.5 ⁇ 10 5, more preferably less than 1.2 ⁇ 10 5 or more 2.5 ⁇ 10 5, 1 More preferably, it is 5 ⁇ 10 5 or more and less than 2.0 ⁇ 10 5 .
  • the molecular weight distribution (weight average molecular weight Mw / number average molecular weight Mn) of cellulose acetate is preferably 1.8 to 4.5.
  • the number average molecular weight and weight average molecular weight of cellulose acetate can be measured by gel permeation chromatography (GPC).
  • the measurement conditions are as follows. Solvent: Methylene chloride Column: Three Shodex K806, K805, K803G (manufactured by Showa Denko KK) are connected and used.
  • the content of alkaline earth metal (calcium, magnesium) contained in cellulose acetate is preferably less than 30 ppm by mass, more preferably less than 20 ppm by mass, and more preferably less than 10 ppm by mass. .
  • the alkaline earth metal content is 30 mass ppm or more, the peeling force from the metal support of the dope film in the step of producing the optical compensation film by the solution casting method becomes too strong, Defects such as horizontal rows are likely to occur.
  • cellulose which is a raw material for cellulose acetate, include cotton linter, wood pulp (derived from coniferous trees, derived from broadleaf trees), kenaf and the like.
  • the cellulose used as a raw material may be only one type or a mixture of two or more types.
  • glass transition temperature reducing agents include polyester compounds, polyhydric alcohol ester compounds, polyvalent carboxylic acid ester compounds (including phthalic acid ester compounds), glycolate compounds, and ester compounds (fatty acid ester compounds). And phosphate compound). These may be used alone or in combination of two or more.
  • the polyester compound is preferably a polyester compound represented by the general formula (I).
  • a in the general formula (I) represents an arylene group having 6 to 14 carbon atoms, a linear or branched alkylene group having 2 to 6 carbon atoms, or a cycloalkylene group having 3 to 10 carbon atoms, and is excellent in Tg reducing ability. Therefore, an arylene group having 6 to 14 carbon atoms is preferable, and a phenylene group, a naphthylene group, or a biphenylylene group is more preferable.
  • B represents a linear or branched alkylene group having 2 to 6 carbon atoms or a cycloalkylene group having 3 to 10 carbon atoms.
  • X represents a hydrogen atom or a residue of an aromatic monocarboxylic acid having 6 to 14 carbon atoms or an aliphatic monocarboxylic acid having 1 to 6 carbon atoms, preferably a hydrogen atom or an aromatic monocarboxylic acid having 6 to 14 carbon atoms. It is an acid residue.
  • n represents a natural number of 1 or more.
  • the polyester compound represented by the general formula (I) is a dicarboxylic acid having an arylene group having 6 to 14 carbon atoms, a linear or branched alkylene group having 2 to 6 carbon atoms, or a cycloalkylene group having 3 to 10 carbon atoms. And a diol having a linear or branched alkylene group having 2 to 6 carbon atoms or a cycloalkylene group having 3 to 10 carbon atoms, and then, if necessary, aromatic monocarboxylic acid or aliphatic monocarboxylic acid It can be obtained by sealing the end with an acid.
  • dicarboxylic acid having an arylene group having 6 to 14 carbon atoms examples include phthalic acid, isophthalic acid, terephthalic acid, 1,5-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,8-naphthalenedicarboxylic acid, 2,2′-biphenyldicarboxylic acid, 4,4′-biphenyldicarboxylic acid, and the like, preferably terephthalic acid 2,6-naphthalenedicarboxylic acid and 4,4′-biphenyldicarboxylic acid.
  • the arylene group contained in these dicarboxylic acids may further have a substituent such as an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, or an alkoxy group having 1 to 6 carbon atoms.
  • dicarboxylic acid having a linear or branched alkylene group having 2 to 6 carbon atoms examples include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, etc., preferably succinic acid, adipine It is an acid.
  • dicarboxylic acid having a cycloalkylene group having 3 to 10 carbon atoms examples include 1,2-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid and the like, and preferably 1,4-cyclohexanedicarboxylic acid.
  • Examples of the diol having a linear or branched alkylene group having 2 to 6 carbon atoms include ethanediol (ethylene glycol), 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, , 3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, etc.
  • Preferred are ethanediol (ethylene glycol), 1,2-propanediol, 1,3-propanediol, and 1,3-butanediol.
  • diol having a linear or branched cycloalkylene group having 3 to 10 carbon atoms examples include 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and the like.
  • residues of aromatic monocarboxylic acids having 6 to 14 carbon atoms include residues of benzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, p-tert-butylbenzoic acid, dimethylbenzoic acid, and paramethoxybenzoic acid.
  • it is a residue of benzoic acid, p-toluic acid, p-tert-butylbenzoic acid.
  • residue of an aliphatic monocarboxylic acid having 1 to 6 carbon atoms include residues of acetic acid, propionic acid, butanoic acid and the like.
  • polyester compound represented by formula (I) Specific examples of the polyester compound represented by formula (I) are shown below. In the following specific examples, all X in the general formula (I) may be hydrogen atoms.
  • the polyhydric alcohol ester compound is an ester compound (alcohol ester) of a dihydric or higher aliphatic polyhydric alcohol and a monocarboxylic acid, preferably a divalent to 20-valent aliphatic polyhydric alcohol ester.
  • the polyhydric alcohol ester compound preferably has an aromatic ring or a cycloalkyl ring in the molecule.
  • Preferred examples of the aliphatic polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2- Butanediol, 1,3-butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, trimethylolpropane , Pentaerythritol, trimethylolethane, xylitol and the like.
  • triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, sorbitol, trimethylolpropane, xylitol and the like are preferable.
  • the monocarboxylic acid is not particularly limited, and may be an aliphatic monocarboxylic acid, an alicyclic monocarboxylic acid, an aromatic monocarboxylic acid, or the like. In order to increase the moisture permeability of the film and make it difficult to volatilize, alicyclic monocarboxylic acid or aromatic monocarboxylic acid is preferred.
  • One kind of monocarboxylic acid may be used, or a mixture of two or more kinds may be used. Further, all of the OH groups contained in the aliphatic polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are.
  • the aliphatic monocarboxylic acid is preferably a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms.
  • the number of carbon atoms of the aliphatic monocarboxylic acid is more preferably 1-20, and still more preferably 1-10.
  • aliphatic monocarboxylic acids examples include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanoic acid, undecylic acid, lauric acid, tridecylic acid , Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, and laccelic acid; undecylenic acid, Examples include unsaturated fatty acids such as oleic acid, sorbic acid, linoleic acid, linolenic acid, and arachidonic acid. Of these, acetic acid or a mixture of
  • Examples of the alicyclic monocarboxylic acid include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid and the like.
  • aromatic monocarboxylic acids examples include benzoic acid; one having 1 to 3 alkyl groups or alkoxy groups (for example, methoxy group or ethoxy group) introduced into the benzene ring of benzoic acid (for example, toluic acid); benzene ring Aromatic monocarboxylic acids having two or more (for example, biphenyl carboxylic acid, naphthalene carboxylic acid, tetralin carboxylic acid, etc.) are included, and benzoic acid is preferred.
  • polyhydric alcohol ester compound examples include the following.
  • divalent alcohol ester compound examples include the following.
  • Examples of the trivalent or higher alcohol ester compound include the following compounds.
  • the polyvalent carboxylic acid ester compound is an ester compound of a divalent or higher, preferably 2 to 20 valent polycarboxylic acid and an alcohol compound.
  • the polyvalent carboxylic acid is preferably a divalent to 20-valent aliphatic polyvalent carboxylic acid, a 3- to 20-valent aromatic polyvalent carboxylic acid, or a 3- to 20-valent alicyclic polyvalent carboxylic acid. .
  • polyvalent carboxylic acids include trivalent or higher aromatic polyvalent carboxylic acids such as trimellitic acid, trimesic acid, pyromellitic acid or derivatives thereof, succinic acid, adipic acid, azelaic acid, sebacic acid, oxalic acid Contains aliphatic polycarboxylic acids such as fumaric acid, maleic acid, and tetrahydrophthalic acid, and oxypolycarboxylic acids such as tartaric acid, tartronic acid, malic acid, and citric acid, and suppresses volatilization from the film. For this, oxypolycarboxylic acids are preferred.
  • the alcohol compound examples include an aliphatic saturated alcohol compound having a straight chain or a side chain, an aliphatic unsaturated alcohol compound having a straight chain or a side chain, an alicyclic alcohol compound, or an aromatic alcohol compound.
  • the carbon number of the aliphatic saturated alcohol compound or the aliphatic unsaturated alcohol compound is preferably 1 to 32, more preferably 1 to 20, and still more preferably 1 to 10.
  • Examples of the alicyclic alcohol compound include cyclopentanol, cyclohexanol and the like.
  • the aromatic alcohol compound include benzyl alcohol and cinnamyl alcohol.
  • the molecular weight of the polyvalent carboxylic acid ester compound is not particularly limited, but is preferably 300 to 1000, and more preferably 350 to 750.
  • the molecular weight of the polyvalent carboxylic acid ester plasticizer is preferably larger from the viewpoint of suppressing bleeding out; it is preferably smaller from the viewpoint of moisture permeability and compatibility with cellulose acetate.
  • polyvalent carboxylic acid ester compounds include triethyl citrate, tributyl citrate, acetyl triethyl citrate (ATEC), acetyl tributyl citrate (ATBC), benzoyl tributyl citrate, acetyl triphenyl citrate, acetyl tribenzyl citrate Rate, dibutyl tartrate, diacetyl dibutyl tartrate, tributyl trimellitic acid, tetrabutyl pyromellitic acid and the like.
  • ATEC acetyl triethyl citrate
  • ATBC acetyl tributyl citrate
  • benzoyl tributyl citrate acetyl triphenyl citrate
  • acetyl tribenzyl citrate Rate dibutyl tartrate
  • diacetyl dibutyl tartrate diacetyl dibutyl tartrate
  • tributyl trimellitic acid
  • the polyvalent carboxylic acid ester compound may be a phthalic acid ester compound.
  • the phthalic acid ester compound include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, dicyclohexyl terephthalate and the like.
  • glycolate compounds include alkylphthalyl alkyl glycolates.
  • alkyl phthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate, methyl phthalyl Ethyl glycolate, ethyl phthalyl methyl glycolate, ethyl phthalyl propyl glycolate, methyl phthalyl butyl glycolate, ethyl phthalyl butyl glycolate, butyl phthalyl methyl glycolate, butyl phthalyl ethyl glycolate, propyl phthalyl butyl Glycolate, butyl phthalyl propyl glycolate, methyl phthalyl octyl glycolate, ethyl phthalyl
  • the ester compound includes a fatty acid ester compound, a citrate ester compound, a phosphate ester compound, and the like.
  • Examples of fatty acid ester compounds include butyl oleate, methylacetyl ricinoleate, and dibutyl sebacate.
  • Examples of the citrate ester compound include acetyltrimethyl citrate, acetyltriethyl citrate, and acetyltributyl citrate.
  • Examples of the phosphate ester compound include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, biphenyl diphenyl phosphate, trioctyl phosphate, tributyl phosphate, and the like.
  • polyhydric alcohol ester compounds glycolate compounds, and phosphate ester compounds are preferred.
  • the Tg lowering ability of the glass transition temperature reducing agent is preferably 3.5 ° C./mass part or more, more preferably 3.8 ° C./mass part or more, and further preferably 4.0 ° C./mass part or more. is there.
  • the Tg lowering ability of the glass transition temperature lowering agent is within the above range, an excellent Tg lowering effect can be obtained even with a small addition amount.
  • the Tg lowering ability of the glass transition temperature lowering agent is usually 10.0 ° C./part by mass or less.
  • the Tg lowering ability of the glass transition temperature lowering agent is defined by the following formula.
  • X represents Tg of a film composed of cellulose acetate
  • Y represents Tg of a film composed of 100 parts by mass of cellulose acetate and 5 parts by mass of a glass transition temperature reducing agent.
  • the Tg of the film can be measured by differential scanning calorimetry (DSC).
  • the Fedors solubility parameter value (SP value) of the glass transition temperature lowering agent in the dope liquid used in the film production process is preferably smaller than the absolute value of the difference between the SP value of the glass transition temperature reducing agent and the SP value of cellulose acetate.
  • the absolute value of the difference between the SP value of the glass transition temperature reducing agent and the SP value of cellulose acetate is preferably 0.5 or more, more preferably 1.0 or more.
  • the SP value of the glass transition temperature reducing agent is preferably in the range of 9.5 to 11.5.
  • the content of the glass transition temperature lowering agent is preferably 1 to 15% by mass, more preferably 1.5 to 10% by mass with respect to the whole cellulose acetate including the low substitution degree component.
  • the content of the glass transition temperature lowering agent is less than 1% by mass, the Tg lowering effect by the glass transition temperature lowering agent may not be sufficient.
  • the content of the glass transition temperature lowering agent is more than 10% by mass, the retardation of the optical compensation film containing it may not be sufficiently obtained.
  • the optical compensation film may further contain fine particles (matting agent) in order to increase the slipperiness of the surface.
  • the fine particles may be inorganic fine particles or organic fine particles.
  • inorganic fine particles include silicon dioxide (silica), titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, Examples include magnesium silicate and calcium phosphate. Of these, silicon dioxide and zirconium oxide are preferable, and silicon dioxide is more preferable in order to reduce an increase in haze of the obtained film.
  • Examples of fine particles of silicon dioxide include Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600, NAX50 (manufactured by Nippon Aerosil Co., Ltd.), Sea Hoster KE-P10, KE-P30, KE-P50, KE-P100 (manufactured by Nippon Shokubai Co., Ltd.) and the like are included.
  • Aerosil R972V, NAX50, Seahoster KE-P30 and the like are particularly preferable because the coefficient of friction can be reduced while the turbidity of the resulting film is kept low.
  • the primary particle diameter of the fine particles is preferably 5 to 50 nm, more preferably 7 to 20 nm.
  • a larger primary particle size has a greater effect of increasing the slipperiness of the resulting film, but transparency tends to decrease. Therefore, the fine particles may be contained as secondary aggregates having a particle diameter of 0.05 to 0.3 ⁇ m.
  • the size of the primary particles or secondary aggregates of the fine particles was determined by observing the primary particles or secondary aggregates at a magnification of 500,000 to 2,000,000 times with a transmission electron microscope, and measuring 100 primary particles or secondary aggregates. It can be determined as an average value of the particle diameter.
  • the content of the fine particles is preferably 0.05 to 1.0% by mass, more preferably 0.1 to 0.8% by mass with respect to the whole cellulose acetate including the low substitution degree component.
  • the optical compensation film is preferably a single layer in order to easily concentrate the transmitted scattered light in the normal direction (front direction) of the film.
  • the display device including the film containing cellulose diacetate tends to have a contrast in the oblique direction significantly lower than the contrast in the front direction.
  • the contrast of the liquid crystal display device depends on light leakage during black display.
  • the inventors of the present invention have the reason that the contrast in the oblique direction of the display device is remarkably lower than the contrast in the front direction because of the angle dependency ( ⁇ 30 - ⁇ 0 ) of the optical rotation of the film containing cellulose diacetate. I found out that it was big.
  • the film containing cellulose diacetate has a greater optical rotation angle dependency ( ⁇ 30 - ⁇ 0 ) than the film containing a cyclic olefin resin; It tends to be larger than light leakage in the direction. As a result, the contrast in the oblique direction tends to be lower than the contrast in the front direction. The reason for this is not necessarily clear, but cellulose diacetate is thought to be because the van der Waals radius of the monomer units constituting it is small and has many asymmetric carbons.
  • the present invention is characterized in that the light leakage in the front direction due to scattering is made larger than the light leakage in the oblique direction due to scattering.
  • the difference between the light leakage in the front direction due to the optical rotation and the light leakage in the oblique direction due to the optical rotation can be canceled; the difference between the total light leakage in the front direction and the total light leakage in the oblique direction can be reduced.
  • the difference between the contrast in the front direction and the contrast in the oblique direction can be reduced.
  • the intensity of the transmitted scattered light scattered in the front direction is made larger than the intensity of the transmitted scattered light scattered in the oblique direction. Then, the transmitted scattered light may be concentrated in the normal direction (front direction) of the film.
  • the transmission scattering is in the range of 4 to 10 ° with respect to the normal of the surface of the optical compensation film.
  • the ratio of the integrated amount of light intensity I 4-10 to the integrated amount of light scattered light I 4-60 in the range of 4 to 60 ° with respect to the normal of the surface of the optical compensation film is 97% or more. Preferably, it is 98% or more, more preferably 99% or more.
  • the angle of the transmitted scattered light with respect to the normal to the surface of the optical compensation film is also called the scattering angle.
  • the internal haze of the optical compensation film may be increased.
  • a low substitution component as described above cellulose acetate having an acetyl group substitution degree of less than 2.2
  • a glass transition temperature reducing agent is added. What is necessary is just to make uneven distribution in the film thickness direction, or to combine them.
  • the intensity of transmitted scattered light can be measured by the following procedure.
  • a spectrophotometer V670 manufactured by JASCO Corporation and an automatic absolute reflectance measuring unit (ARMN-735) attached thereto are used as a measuring apparatus.
  • the intensity of the transmitted scattered light when light having a wavelength of 550 nm is incident in parallel to the normal line of the sample surface is in the range of 0 ° to 60 ° with respect to the normal line of the sample surface. A total of 31 points are measured every 2 °.
  • the sum of transmitted scattered light intensities measured at a measurement angle of 4 ° to 10 ° with respect to the normal of the sample surface is “integrated amount I 4-10 of transmitted scattered light in the range of scattering angles 4 to 10 °”.
  • the sum of the intensities of the transmitted and scattered light measured at a measurement angle of 4 ° to 60 ° with respect to the normal of the sample surface is “the integrated amount I of transmitted and scattered light in the range of the scattering angle of 4 to 60 ° I 4 ⁇ 60 ". Then, I 4-10 / I 4-60 ⁇ 100 is calculated.
  • the measurement of the intensity of transmitted scattered light can be performed under conditions of 23 ° C. and 55% RH.
  • strength of transmitted scattered light can be made into AGC Fabritech Co., Ltd., alkali free glass substrate CF grade, 39 mm (length) x 50 mm (width) x 0.6 mm (thickness).
  • Glycerin can be a deer special grade (purity> 99.0%) manufactured by Kanto Chemical.
  • the angle dependence of the optical rotation of the film is defined as the rotation angle ⁇ 0 of the polarization plane of the elliptically polarized light that exits when the linearly polarized light is incident in parallel to the normal line of the film surface and the polarization plane of the incident linearly polarized light.
  • the plane of polarization of the incident linearly polarized light exits. Can be expressed as a difference ( ⁇ 30 ⁇ 0 ) with respect to the rotation angle ⁇ 30 with respect to.
  • FIG. 1 A method for measuring the angle dependence of the optical rotation of the film is shown in FIG.
  • the angle dependency of the optical rotation of the film can be measured using an ellipsometer (M-220) manufactured by JASCO Corporation.
  • M-220 ellipsometer manufactured by JASCO Corporation.
  • the plane of polarization of linearly polarized light incident on the film is made parallel to the in-plane slow axis of the film.
  • the rotation angle of the polarization plane of elliptically polarized light after passing through the film with respect to the polarization plane of incident linearly polarized light is defined as ⁇ 0 .
  • linearly polarized light is incident on the film at an angle of 30 ° with respect to the normal of the film surface.
  • the plane of polarization of linearly polarized light incident on the film is made parallel to the in-plane slow axis of the film.
  • the rotation angle of the polarization plane of the elliptically polarized light after passing through the film with respect to the polarization plane of the incident linearly polarized light is defined as ⁇ 30 . 3) Calculate ⁇ 30 - ⁇ 0 .
  • ⁇ 30 - ⁇ 0 of the film containing cellulose diacetate is usually 1.5 ° or more and may be 2.0 or more.
  • the content of the glass transition temperature lowering agent in the vicinity of one surface of the optical compensation film and the other surface is different, and it is more preferable that the glass transition temperature lowering agent is unevenly distributed in the thickness direction of the film.
  • the content of the glass transition temperature reducing agent in the vicinity of one surface of the optical compensation film is preferably 1.1 times or more of the content of the glass transition temperature reducing agent in the vicinity of the other surface. 1.2 times or more is more preferable, and 1.3 times or more is more preferable.
  • the content of the glass transition temperature lowering agent in the vicinity of one surface of the optical compensation film is The content of the glass transition temperature reducing agent in the vicinity of the other surface can be 1.5 times or less.
  • the distribution of the glass transition temperature reducing agent in the thickness direction of the optical compensation film can be confirmed by time-of-flight secondary ion mass spectrometry (TOF-SIMS). That is, the content of the glass transition temperature reducing agent in the vicinity of one surface of the optical compensation film, measured by time-of-flight secondary ion mass spectrometry (TOF-SIMS), is dA, and the glass transition temperature in the vicinity of the other surface.
  • the r value represented by the following formula is preferably 1.1 or more, more preferably 1.2 or more, and 1.3 or more. Further preferred. The upper limit of the r value is usually 1.5.
  • max ⁇ d A , d B ⁇ represents the larger of d A and d B ;
  • min ⁇ d A , d B ⁇ represents the smaller of d A and d B.
  • the content of the glass transition temperature lowering agent on each film surface can be measured by detecting the reference ionic strength caused by the glass transition temperature lowering agent present on the surface of each film using the TOF-SIMS method.
  • the measurement method by the TOF-SIMS method is specifically described in “Surface Analysis Technology Selection, Secondary Ion Mass Spectrometry” edited by the Japan Surface Science Society, published by Maruzen Co., Ltd. (1999).
  • the distribution of the glass transition temperature reducing agent in the thickness direction of the optical compensation film can also be confirmed by the following method. That is, the optical compensation film is cut so that the film thickness is equally divided by a plane parallel to the film surface. And the quantity of the glass transition temperature reducing agent contained in one obtained film is compared with the quantity of the glass transition temperature reducing agent contained in the other film.
  • a glass transition temperature lowering agent having higher affinity with the solvent than cellulose acetate is selected.
  • the optical compensation film of the present invention has an in-plane retardation R 0 of 10 nm measured under conditions of a measurement wavelength of 590 nm and 23 ° C. and 55% RH in order to perform optical compensation of a VA liquid crystal cell, for example.
  • ⁇ R 0 ⁇ 100 nm is preferably satisfied, 30 nm ⁇ R 0 ⁇ 70 nm is more preferable, and 40 nm ⁇ R 0 ⁇ 60 nm is more preferable.
  • RH preferably satisfies 70 nm ⁇ Rth ⁇ 300 nm, and more preferably satisfies 90 nm ⁇ Rth ⁇ 230 nm. Preferably, it is more preferable to satisfy 100 nm ⁇ Rth ⁇ 170 nm.
  • R 0 and Rth can be adjusted by the total substitution degree of acyl groups of cellulose acetate, stretching conditions, and the like.
  • R 0 for example, the total substitution degree of acyl groups of cellulose acetate may be lowered, or the draw ratio may be increased.
  • Rth for example, the stretching temperature and the stretching ratio may be lowered, or the film thickness of the film may be increased.
  • Retardation R0 and Rth are defined by the following equations, respectively.
  • Formula (I): R 0 (nx ⁇ ny) ⁇ d (nm)
  • Formula (II): Rth ⁇ (nx + ny) / 2 ⁇ nz ⁇ ⁇ d (nm)
  • nx represents the refractive index in the slow axis direction x where the refractive index is maximum in the in-plane direction of the optical compensation film
  • ny represents the refractive index in the direction y orthogonal to the slow axis direction x in the in-plane direction of the optical compensation film
  • nz represents the refractive index in the thickness direction z of the optical compensation film
  • d (nm) represents the thickness of the optical compensation film
  • the retardations R0 and Rth can be determined by the following method, for example. 1) The humidity of the optical compensation film is adjusted at 23 ° C. and 55% RH. The average refractive index of the optical compensation film after humidity adjustment is measured with an Abbe refractometer or the like. 2) R0 when light having a measurement wavelength of 590 nm is incident on the optical compensation film after humidity adjustment in parallel with the normal line of the film surface is measured with KOBRA21ADH manufactured by Oji Scientific Co., Ltd.
  • the angle of ⁇ (incident angle ( ⁇ )) with respect to the normal of the surface of the optical compensation film with the slow axis in the plane of the optical compensation film as the tilt axis (rotation axis)
  • the retardation value R ( ⁇ ) can be measured at 6 points every 10 ° in the range of 0 ° to 50 °.
  • the in-plane slow axis of the optical compensation film can be confirmed by KOBRA 21ADH manufactured by Oji Scientific Co., Ltd.
  • nx, ny and nz are calculated by KOBRA 21ADH manufactured by Oji Scientific Co., Ltd., and Rth at a measurement wavelength of 590 nm is calculated. Is calculated.
  • the measurement of retardation can be performed under conditions of 23 ° C. and 55% RH.
  • the angle ⁇ 1 (orientation angle) formed by the in-plane slow axis of the optical compensation film and the width direction of the film is preferably ⁇ 1 ° to + 1 °, more preferably ⁇ 0.5 ° to + 0.5 °. is there.
  • the orientation angle ⁇ 1 of the optical compensation film can be measured using an automatic birefringence meter KOBRA-WX (Oji Scientific Instruments).
  • the thickness of the optical compensation film is preferably not more than 200 ⁇ m, more preferably not more than 100 ⁇ m, and still more preferably not more than 60 ⁇ m in order to reduce fluctuations in retardation due to heat and humidity.
  • the thickness of the optical compensation film is preferably 10 ⁇ m or more, and more preferably 20 ⁇ m or more in order to obtain film strength and retardation that can function as a protective film.
  • the haze (total haze) of the optical compensation film is preferably 1.0% or less.
  • the haze (total haze) of the optical compensation film can be measured with a haze meter (turbidimeter) (model: NDH 2000, manufactured by Nippon Denshoku Co., Ltd.) in accordance with JIS K-7136.
  • the light source of the haze meter may be a 5V9W halogen sphere, and the light receiving part may be a silicon photocell (with a relative visibility filter). All measurements of haze are performed under conditions of 23 ° C. and 55% RH.
  • the internal haze of the optical compensation film is preferably 0.01 to 0.1%. It is not realistic to set the internal haze to less than 0.01%, and if it exceeds 0.1%, the front contrast is greatly deteriorated, which is not preferable.
  • the internal haze of the optical compensation film can be measured by the method described in JP-A-2009-286931; specifically, the following method.
  • a haze meter (turbidity meter) (model: NDH 2000, manufactured by Nippon Denshoku Co., Ltd.) is prepared.
  • the light source is a 5V9W halogen sphere, and the light receiving unit is a silicon photocell (with a relative visibility filter).
  • 1) Measurement of blank haze One drop (0.05 ml) of glycerin is dropped on the washed slide glass. At this time, care is taken so that bubbles do not enter the droplet. Next, a cover glass is placed on the dropped glycerin. Glycerin spreads without pressing the cover glass.
  • a blank measurement sample (cover glass / glycerin / slide glass) obtained in this manner is set on a haze meter, and haze 1 (blank haze) is measured.
  • 2) Measurement of haze of sample including optical compensation film Glycerin is dropped onto the washed slide glass in the same manner as in 1) above.
  • the optical compensation film to be measured is conditioned at 23 ° C. and 55% RH for 5 hours or more.
  • a conditioned optical compensation film is placed on the dropped glycerin so that air bubbles do not enter.
  • 0.05 ml of glycerin is dropped on the optical compensation film, and then a cover glass is further placed thereon.
  • the glass used for the measurement of internal haze shall be MICRO SLIDE GLASS S9213 MATSUNAMI.
  • Glycerin is manufactured by Kanto Chemical Co., Ltd., deer special grade (purity> 99.0%), with a refractive index of 1.47.
  • the visible light transmittance of the optical compensation film is preferably 90% or more, and more preferably 93% or more.
  • the optical compensation film is produced by a solution casting method or a melt casting method, preferably by a solution casting method.
  • a method for producing an optical compensation film containing cellulose acetate by a solution casting method is as follows: 1) a step of preparing a dope by dissolving at least cellulose acetate and, if necessary, other additives in a solvent; 2) a dope A step of casting on an endless metal support, 3) a step of evaporating the solvent from the cast dope to form a web, 4) a step of peeling the web from the metal support, 5) drying and stretching the web And obtaining a film.
  • Dope preparation step In a dissolution vessel, a dope is prepared by dissolving cellulose acetate and other additives as required in a solvent.
  • the solvent contained in the dope may be a single type or a combination of two or more types. From the viewpoint of increasing production efficiency, it is preferable to use a combination of a good solvent and a poor solvent for cellulose acetate.
  • a good solvent refers to a solvent that dissolves cellulose acetate alone
  • a poor solvent refers to a solvent that swells cellulose acetate or does not dissolve alone. Therefore, the good solvent and the poor solvent differ depending on the average acyl group substitution degree (acetyl group substitution degree) of cellulose acetate.
  • the good solvent is more than the poor solvent in order to increase the solubility of cellulose acetate.
  • the mixing ratio of the good solvent and the poor solvent is preferably 70 to 98% by mass for the good solvent and 2 to 30% by mass for the poor solvent.
  • Examples of good solvents include organic halogen compounds such as dichloromethane, dioxolanes, acetone, methyl acetate, and methyl acetoacetate, and preferably dichloromethane or methyl acetate.
  • Examples of the poor solvent include methanol, ethanol, n-butanol, cyclohexane, cyclohexanone and the like.
  • the concentration of cellulose acetate in the dope is preferably higher in order to reduce the drying load. However, if the concentration of cellulose acetate is too high, filtration is difficult. Therefore, the concentration of cellulose acetate in the dope is preferably 10 to 35% by mass, more preferably 15 to 25% by mass.
  • the dope may further contain a glass transition temperature lowering agent.
  • the Fedors solubility parameter values (SP values) of cellulose acetate, glass transition temperature lowering agent and solvent are respectively SP C and SP.
  • G when the SP S, it is preferable to select the materials so as to satisfy the following relationship.
  • SP value of glass transition temperature lowering agent (SP G) and the SP value of the solvent the absolute value of the difference between the (SP S), the SP value of the glass transition temperature lowering agent (SP G) and the SP value of cellulose acetate ( It is preferable to make it smaller than the absolute value of the difference from SP c ). It means that the smaller the absolute value of the difference in SP value is, the more easily the substances are dissolved.
  • is preferably 1.1 times or more of
  • the SP value is one of important parameters for predicting the hydrophilicity / hydrophobicity of various chemical substances, and can be defined by the heat of molar evaporation ⁇ H and the molar volume V in regular solution theory.
  • the SP value can be predicted empirically, and can be obtained by calculation using parameters such as Hoy, Fedors, or Small.
  • the SP value in the present invention is preferably obtained by calculation using Fedors parameters that are rich in parameters and can be applied to a wide range of compounds.
  • the unit of SP value is the square root of the value obtained by dividing the cohesive energy density ⁇ E by the molar volume V, and “(cm 3 / cal) 1/2 ” can be used.
  • the parameters of Fedors are described in References: Basic Science of Coatings by Yuji Harada, Kashiwa Shoten (1977), p.
  • the solvent evaporates from the surface of the dope film that is not in contact with the metal support (surface that is in contact with air). Therefore, the solvent concentration in the vicinity of the surface of the dope film in contact with the metal support becomes higher than the solvent concentration in the vicinity of the surface not in contact with the metal support (surface in contact with air), and the concentration gradient of the solvent in the thickness direction of the dope film Arise. If the glass transition temperature lowering agent has a higher affinity with the solvent than cellulose acetate, it is considered that the glass transition temperature lowering agent tends to be present in the vicinity of the surface in contact with the metal support having a high solvent concentration.
  • Examples of the method of dissolving cellulose acetate in a solvent include a method of dissolving under heating and pressure, a method of adding a poor solvent to cellulose acetate to swell, a method of further adding a good solvent, and a cooling dissolution method. sell.
  • dissolve under a heating and pressurization is preferable.
  • stirring and dissolving while heating to a temperature in the range where the solvent is boiling or higher under normal pressure and the solvent does not boil under pressure the generation of bulk undissolved material called gel or mako can be suppressed.
  • the heating temperature is preferably higher from the viewpoint of increasing the solubility of cellulose acetate, but if it is too high, it is necessary to increase the pressure and the productivity is lowered. For this reason, the heating temperature is preferably 45 to 120 ° C., more preferably 60 to 110 ° C., and further preferably 70 to 105 ° C.
  • the obtained dope may contain insoluble matters such as impurities contained in cellulose acetate as a raw material. Such an insoluble matter can become a bright spot foreign material in the obtained film. In order to remove such insoluble matter and the like, it is preferable to further filter the obtained dope.
  • the dope is fed to a pressure die through a liquid feed pump (for example, a pressurized metering gear pump) and pressurized on an endless metal support (for example, a stainless steel belt or a rotating metal drum). Cast from the die slit.
  • a liquid feed pump for example, a pressurized metering gear pump
  • an endless metal support for example, a stainless steel belt or a rotating metal drum
  • the die is preferably a pressure die that can adjust the slit shape of the die part and easily adjust the film thickness uniformly.
  • Examples of the pressure die include a coat hanger die and a T-die.
  • the surface of the metal support is preferably mirror-finished.
  • the web is preferably dried in an atmosphere of 40 to 100 ° C.
  • a method for evaporating the solvent there are a method in which air is applied to the surface of the web, a method in which heat is transferred from the back surface of the belt by liquid, a method in which heat is transferred from the front and back by radiant heat, etc.
  • a method in which heat is transferred from the back surface with a liquid is preferable.
  • the web in which the solvent is evaporated on the metal support is peeled off at the peeling position on the metal support.
  • the temperature at the peeling position on the metal support is preferably 10 to 40 ° C., more preferably 11 to 30 ° C.
  • the residual solvent amount of the web when peeling at the peeling position on the metal support depends on the drying conditions and the length of the metal support, but is preferably 50 to 120% by mass.
  • a web having a large amount of residual solvent is too soft and tends to impair flatness, and is liable to cause slippage and vertical stripes due to peeling tension.
  • the residual solvent amount of the web at the peeling position can be set so that such slippage and vertical stripes can be suppressed.
  • the heat treatment for measuring the residual solvent amount means a heat treatment at 115 ° C. for 1 hour.
  • the amount of residual solvent in the web when the web is peeled from the metal support It is preferable to sufficiently reduce the amount of solvent on the side of the web that is not in contact with the metal support by reducing the value to a certain value or less.
  • the residual solvent amount in the web is preferably 90% by mass or less, more preferably 85% by mass or less, and even more preferably 80% by mass or less.
  • the amount of residual solvent in the web can be adjusted by the drying temperature and drying time.
  • the drying temperature can be preferably about 25 to 50 ° C., more preferably about 35 to 45 ° C.
  • the drying time is preferably about 15 to 150 seconds.
  • the peeling tension when peeling the web from the metal support can usually be 300 N / m or less.
  • Drying and stretching step The web obtained by peeling from the metal support is dried and then stretched.
  • the web may be dried while being transported by a large number of rolls arranged vertically, or may be dried while being transported while fixing both ends of the web with clips.
  • the method for drying the web may be a method of drying with hot air, infrared rays, a heating roll, microwaves, or the like, and a method of drying with hot air is preferable because it is simple.
  • the drying temperature of the web can be about 40 to 250 ° C., preferably about 40 to 160 ° C.
  • the optical compensation film having a desired retardation is obtained by stretching the web.
  • the retardation of the optical compensation film can be controlled by adjusting the magnitude of the tension applied to the web.
  • the stretching of the web is the stretching in the width direction (TD direction), the dope casting direction (MD direction), or the oblique direction, and is preferably stretched at least in the width direction (TD direction).
  • the web may be stretched uniaxially or biaxially.
  • Biaxial stretching is preferably stretching in the dope casting direction (MD direction) and the width direction (TD direction).
  • Biaxial stretching may be sequential biaxial stretching or simultaneous biaxial stretching.
  • Sequential biaxial stretching includes a method in which stretching in different stretching directions is sequentially performed, a method in which stretching in the same direction is performed in multiple stages, and the like.
  • Examples of sequential biaxial stretching include the following stretching steps. Stretch in the casting direction (MD direction)-Stretch in the width direction (TD direction)-Stretch in the casting direction (MD direction)-Stretch in the casting direction (MD direction) Stretch in the width direction (TD direction)-Stretch in the width direction Stretching (TD direction)-Stretching in the casting direction (MD direction)-Stretching in the casting direction (MD direction)-Stretching in the casting direction (MD direction)
  • Simultaneous biaxial stretching includes a mode in which stretching is performed in one direction and the tension in the other direction is relaxed and contracted.
  • the draw ratio depends on the film thickness of the optical compensation film to be obtained and the required retardation value, it is finally 0.8 to 1.5 times, preferably 0.8 to 1.times.
  • the draw ratio depends on the film thickness of the optical compensation film to be obtained and the required retardation value, it is finally 0.8 to 1.5 times, preferably 0.8 to 1.times.
  • In the casting direction. 1 times; 1.1 to 2.0 times, preferably 1.3 to 1.7 times in the width direction.
  • the stretching speed is preferably 70 to 200 mm / sec, more preferably 130 to 180 mm / sec.
  • the stretching temperature of the web is preferably 120 ° C. to 200 ° C., more preferably 150 ° C. to 200 ° C., and even more preferably more than 150 ° C. and 190 ° C. or less.
  • the stretching method of the web is not particularly limited, and a method (roll stretching method) in which a circumferential speed difference is applied to a plurality of rolls, and the roll circumferential speed difference is utilized to stretch in the casting direction (MD direction). Fix both ends with clips and pins, and widen the gap between the clips and pins in the casting direction (MD direction) and extend in the casting direction (MD direction), or widen in the width direction (TD direction) and the width direction (TD direction) or a method of extending in both the casting direction (MD direction) and the width direction (TD direction) by extending both in the casting direction (MD direction) and the width direction (TD direction) ( And a tenter stretching method). These stretching methods may be combined.
  • the residual solvent of the web at the start of stretching is preferably 20% by mass or less, more preferably 15% by mass or less.
  • Polarizing plate The polarizing plate of the present invention includes a polarizer and the optical compensation film of the present invention disposed on at least one surface thereof.
  • the optical compensation film of the present invention may be disposed directly on the polarizer or may be disposed through another film or layer.
  • a polarizer is an element that allows only light of a polarization plane in a certain direction to pass through.
  • a typical example of the polarizer is a polyvinyl alcohol-based polarizing film, and there are one in which a polyvinyl alcohol-based film is dyed with iodine and one in which a dichroic dye is dyed.
  • the polarizer may be a film obtained by uniaxially stretching a polyvinyl alcohol film and then dyeing with iodine or a dichroic dye, or after dyeing a polyvinyl alcohol film with iodine or a dichroic dye, A uniaxially stretched film (preferably a film further subjected to durability treatment with a boron compound) may be used.
  • the thickness of the polarizer is preferably 5 to 30 ⁇ m, more preferably 10 to 20 ⁇ m.
  • the polyvinyl alcohol film may be a film formed from a polyvinyl alcohol aqueous solution.
  • the polyvinyl alcohol film is preferably an ethylene-modified polyvinyl alcohol film because it is excellent in polarizing performance and durability performance and has few color spots.
  • Examples of the ethylene-modified polyvinyl alcohol film include an ethylene unit content of 1 to 4 mol%, a degree of polymerization of 2000 to 4000, and a degree of saponification of 99 described in JP-A Nos. 2003-248123 and 2003-342322. 0.0-99.99 mol% film is included.
  • dichroic dyes examples include azo dyes, stilbene dyes, pyrazolone dyes, triphenylmethane dyes, quinoline dyes, oxazine dyes, thiazine dyes and anthraquinone dyes.
  • a transparent protective film other than the optical compensation film of the present invention may be disposed on the other surface of the polarizer.
  • the transparent protective film is not particularly limited, and may be a normal cellulose ester film or the like.
  • cellulose ester films examples include commercially available cellulose ester films (for example, Konica Minoltak KC8UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC6UY, KC4UY, KC4UE, KC8UE-R, KC8UY-HA, KC8UXW-RHA-C, KC8UXW-RHA-NC, KC4UXW-RHA-NC, manufactured by Konica Minolta Opto Co., Ltd.) are preferably used.
  • cellulose ester films for example, Konica Minoltak KC8UX, KC5UX, KC8UCR3, KC8UCR4, KC8UCR5, KC8UY, KC6UY, KC4UY, KC4UE, KC8UE-R, KC8UY-HA, KC8UXW-RHA-C, KC8UX
  • the thickness of the transparent protective film is not particularly limited, but can be about 10 to 200 ⁇ m, preferably 10 to 100 ⁇ m, more preferably 10 to 70 ⁇ m.
  • the polarizing plate can be usually manufactured through a step of bonding a polarizer and the optical compensation film of the present invention.
  • a polarizer and the optical compensation film of the present invention As the adhesive used for bonding, for example, a completely saponified polyvinyl alcohol aqueous solution is preferably used.
  • the liquid crystal display device of the present invention includes a liquid crystal cell and a pair of polarizing plates that sandwich the liquid crystal cell. And at least one of a pair of polarizing plates contains the optical compensation film of this invention, Preferably both of a pair of polarizing plates contain the optical compensation film of this invention.
  • FIG. 3 is a schematic diagram showing a basic configuration of an embodiment of the liquid crystal display device according to the present invention.
  • the liquid crystal display device 10 includes a liquid crystal cell 20, a first polarizing plate 40 and a second polarizing plate 60 that sandwich the liquid crystal cell 20, and a backlight 80.
  • the display method of the liquid crystal cell 20 is not particularly limited, and is a TN (Twisted Nematic) method, a STN (Super Twisted Nematic) method, an IPS (In-Plane Switching) method, an OCB (Optically Compensated BirrefrenceAbirefringenceAbirefringenceAbirefringenceAbirefringenceAbirefringenceAbirefringenceAbirefringenceAbirefringenceAbirefringenceAbirefringenceAbirefringenceAbireflenceAbireflenceAbirefrence
  • MVA Multi-domain Vertical Alignment
  • PVA including Patterned Vertical Alignment
  • HAN Hybrid Aligned Nematic
  • the VA liquid crystal cell has a pair of transparent substrates and a liquid crystal layer sandwiched between them.
  • one transparent substrate is provided with a pixel electrode for applying a voltage to liquid crystal molecules.
  • the counter electrode may be arranged on the one transparent substrate (on which the pixel electrode is arranged) or on the other transparent substrate. In order to increase the aperture ratio, (the pixel electrode is arranged) It is preferable to arrange on one of the transparent substrates.
  • the liquid crystal layer includes liquid crystal molecules having negative or positive dielectric anisotropy.
  • the pixel electrode is disposed on one transparent substrate and the counter electrode is disposed on the other transparent substrate, it is preferable to use liquid crystal molecules having negative dielectric anisotropy.
  • both the pixel electrode and the counter electrode are arranged on one transparent substrate, it is preferably a liquid crystal molecule having positive dielectric anisotropy.
  • Liquid crystal molecules are liquid crystal molecules when no voltage is applied (when no electric field is generated between the pixel electrode and the counter electrode) due to the alignment regulating force of the alignment film provided on the liquid crystal layer side surface of the transparent substrate. Are oriented so that their major axes are substantially perpendicular to the surface of the transparent substrate.
  • an electric field is generated between the pixel electrode and the counter electrode by applying an image signal (voltage) to the pixel electrode.
  • the liquid crystal molecules initially aligned perpendicularly to the surface of the transparent substrate are aligned so that the major axis thereof is in the horizontal direction with respect to the substrate surface.
  • the liquid crystal layer is driven, and the image display is performed by changing the transmittance and reflectance of each sub-pixel.
  • the 1st polarizing plate 40 is arrange
  • the 2nd polarizing plate 60 is arrange
  • One of the protective films 46 (F2) and 64 (F3) may be omitted as necessary.
  • the protective films 44 (F1), 46 (F2), 64 (F3) and 66 (F4) at least one of the protective films 46 (F2) and 64 (F3) disposed on the liquid crystal cell side is used in the present invention.
  • An optical compensation film is preferable.
  • the glass transition temperature is decreased. It is preferable to arrange so that the surface with the larger content of the agent is on the polarizer side.
  • the liquid crystal display device of the present invention comprises an optical compensation film containing cellulose acetate having a substitution degree of acetyl group of 2.2 to 2.5 as a main component and having I 4-10 / I 4-60 adjusted to a certain level or more. Including. Therefore, even if it is an optical compensation film containing cellulose acetate having an acetyl group substitution degree of 2.2 to 2.5 as a main component, the difference between the contrast in the oblique direction and the contrast in the front direction of the display device is reduced, Contrast unevenness due to viewing angle can be reduced.
  • Synthesis of cellulose acetate (Synthesis Example 1) Kraft-dissolved pulp ( ⁇ -cellulose content: 93%) was crushed with water, then replaced with acetone and dried. To 100 parts by mass of the obtained pulp, 500 parts by mass of acetic acid was uniformly dispersed and mixed at 40 ° C. for 30 minutes to activate the pretreatment.
  • a mixture of 250 parts by mass of acetic anhydride and 4.0 parts by mass of sulfuric acid was added to the pulp after the pretreatment activation, and an esterification reaction was performed by a conventional method. Heat generation was caused by the reaction between water and acetic anhydride contained in the pulp, and the reaction between cellulose and acetic anhydride, but it was adjusted by cooling from the outside. Next, 125 parts by mass of an organic solvent was further added to the obtained reaction product, and an acetylation reaction was carried out while keeping the temperature.
  • the obtained reaction product was heated to remove the organic solvent, and 35 parts by mass of a 20% calcium acetate aqueous solution was added and mixed to completely neutralize the sulfuric acid, so that the calcium acetate became excessive (acetic acid).
  • the amount of calcium was 1.09 times equivalent to the amount of sulfuric acid).
  • the reaction mixture obtained by complete neutralization was kept at 150 ° C. for 50 minutes and then kept at 100 ° C. in the atmosphere. While stirring the reaction mixture, a dilute aqueous acetic acid solution was further added to separate the flaky cellulose acetate. Thereafter, the obtained solid was sufficiently washed with water and dried to obtain flaky cellulose acetate (A).
  • Table 3 shows the physical properties of the cellulose acetate obtained.
  • compositions of cellulose acetate (AAA) and cellulose acetate (A ′) obtained in Synthesis Example 1 were measured by high performance liquid chromatography (HPLC) under the following conditions.
  • High performance liquid chromatography High performance liquid chromatography (HPLC) measurement was performed under the following conditions.
  • Apparatus Waters Alliance type 2695 system
  • Column Silica gel filler (carbon load ratio: 4.6%, bonding functional group: phenyl group, end cap: yes, shape: spherical, average particle size: 4 ⁇ m, pore size: 60 mm , Surface area: 120 m 2 / g), column with an inner diameter of 3.9 mm ⁇ length 150 mm (Waters Nova-Pak Phenyl, 3.9 mm ID ⁇ 150 mm, 4 ⁇ m)
  • Eluent The following eluent (A) and (B) mixture (A / B) was used.
  • FIG. 1 An HPLC chart of cellulose acetate (AAA) and cellulose acetate (A ′) is shown in FIG.
  • the low substitution degree component (area%) in Table 5 described later indicates the ratio of the peak area in the retention time range of 0 to 4 minutes to the total peak area in the retention time range of 0 to 28 minutes in the HPLC chart.
  • Fine Particle Dispersion 1 The following components were stirred and mixed with a dissolver for 50 minutes and then dispersed with Manton Gorin to obtain fine particle dispersion 1.
  • Fine particle dispersion 1 Fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.): 11 parts by mass
  • Ethanol 89 parts by mass
  • Fine Particle Additive Solution 1 The obtained fine particle dispersion 1 was slowly added to a dissolution tank charged with methylene chloride with sufficient stirring. The obtained solution was dispersed with an attritor so that the particle size of the secondary particles of the fine particles became a predetermined size, and then filtered with Finemet NF manufactured by Nippon Seisen Co., Ltd. 1 was obtained.
  • (Fine particle addition liquid 1) Dichloromethane: 99 parts by mass Fine particle dispersion: 5 parts by mass
  • composition of dope solution 1 Dichloromethane (SP value 9.7): 372 parts by mass Ethanol (SP value 12.7): 32 parts by mass Cellulose acetate (AAA) (acetyl group substitution degree Dac: 2.45, weight average molecular weight Mw: 166000): 97 masses Parts Cellulose acetate (A ′) (acetyl group substitution degree Dac: 2.10, weight average molecular weight Mw: 65000): 3 parts by weight Compound A: 5 parts by weight Fine particle additive solution 1: 1 parts by weight
  • the SP value of cellulose acetate (AAA) contained in the dope liquid 1 was 12.1.
  • the obtained dope solution 1 was adjusted to 35 ° C. and uniformly cast onto a stainless steel band support with a width of 1800 mm using a belt casting apparatus.
  • the obtained dope film was evaporated on the stainless steel band support until the residual solvent amount was 88 mass%. Thereafter, the dope film was peeled from the stainless steel band support with a peeling tension of 130 N / m to obtain a web.
  • the solvent contained in the obtained web was further evaporated at 55 ° C. and then slit to 1650 mm width.
  • the obtained web was stretched 40% in a web width direction (TD direction) at 155 ° C. at a speed of 120 mm / sec with a tenter stretching machine.
  • the residual solvent amount of the web when stretching was started was 4.6% by mass.
  • the resulting film was dried at 145 ° C. while being conveyed by many rolls.
  • the conveyance tension was 100 N / m. Thereby, a film 101 having a thickness of 50 ⁇ m was obtained.
  • Example 2 An optical compensation film was obtained in the same manner as in Example 1 except that the type of cellulose acetate A was changed as shown in Table 4 and the stretching conditions were adjusted.
  • Example 5 to 6 and 13 An optical compensation film was obtained in the same manner as in Example 1 except that the content of cellulose acetate B was changed as shown in Table 4 and the stretching conditions were adjusted.
  • Example 7 An optical compensation film was obtained in the same manner as in Example 1 except that the type of the glass transition temperature lowering agent was changed as shown in Table 4 and the stretching conditions were adjusted.
  • Example 10 An optical compensation film was obtained in the same manner as in Example 7 except that the stretching conditions were changed as shown in Table 4.
  • Example 11 to 12 An optical compensation film was obtained in the same manner as in Example 1 except that the type of glass transition temperature reducing agent and the stretching conditions were changed as shown in Table 4.
  • the intensity of transmitted scattered light, the distribution of the glass transition temperature reducing agent in the film thickness direction, R 0 and Rth, total haze and internal haze of the obtained films 101 to 117 were measured by the following methods.
  • the intensity of the transmitted scattered light when light having a wavelength of 550 nm is incident on the measurement sample in parallel to the normal line of the sample surface is 0 to 60 with respect to the normal line of the sample surface.
  • a total of 31 points were measured every 2 ° in the range of °.
  • the sum of transmitted scattered light intensities measured at a measurement angle of 4 ° to 10 ° with respect to the normal of the sample surface is “integrated amount I 4-10 of transmitted scattered light in the range of scattering angles 4 to 10 °”.
  • the sum of the intensities of the transmitted and scattered light measured at a measurement angle of 4 ° to 60 ° with respect to the normal of the sample surface is “the integrated amount I of transmitted and scattered light in the range of the scattering angle of 4 to 60 ° I 4 ⁇ 60 ". Then, I 4-10 / I 4-60 ⁇ 100 was calculated.
  • the measurement of transmitted scattered light was performed under the condition of 23 ° C. and 55% RH.
  • the slide glass used for the measurement of the transmitted scattered light used AGC Fabricec Co., Ltd., non-alkali glass substrate CF grade, 39 mm (length) ⁇ 50 mm (width) ⁇ 0.6 mm (thickness).
  • Time-of-flight secondary ion mass spectrometry TOF-SIMS
  • the content dA of the glass transition temperature lowering agent on one side of the optical compensation film under the following measurement conditions was measured.
  • the obtained values were applied to the following formulas to calculate r values.
  • the ion value of each detected glass transition temperature reducing agent is shown below.
  • Measuring device 2100TRIFT2 (manufactured by Physical Electronics) Measurement mode: Cooling measurement (temperature range -95 to -105 ° C) Primary ion: Ga (15 kV) Measurement area: 60 ⁇ m square Integration time: 2 minutes Ion value (unit: m / Z) of each detected glass transition temperature reducing agent: Compound A: 327 Compound B: 403 Compound C: 235 Compound D: 105 Compound E: 431 The larger of d A and d B is the surface in contact with the metal support in the film manufacturing process; the smaller of d A and d B is the surface not in contact with the metal support .
  • R 0 and Rth In-plane direction retardation R 0 and thickness direction retardation Rth were measured by the following methods. 1) The optical compensation film was conditioned at 23 ° C. and 55% RH. The average refractive index of the optical compensation film after humidity adjustment was measured with an Abbe refractometer or the like. 2) R 0 when light having a measurement wavelength of 590 nm was incident on the optical compensation film after humidity control in parallel with the normal line of the film surface was measured with KOBRA 21ADH manufactured by Oji Scientific Co., Ltd.
  • nx, ny, and nz were calculated by KOBRA21ADH from the measured R 0 and R ( ⁇ ) and the above-described average refractive index and film thickness, and Rth at a measurement wavelength of 590 nm was calculated. The retardation was measured under the conditions of 23 ° C. and 55% RH.
  • the haze (total haze) of the optical compensation film was measured with a haze meter (turbidimeter) (model: NDH 2000, manufactured by Nippon Denshoku Co., Ltd.) according to JIS K-7136.
  • the light source of the haze meter was a 5V9W halogen sphere, and the light receiving part was a silicon photocell (with a relative visibility filter).
  • the haze was measured under the condition of 23 ° C. and 55% RH.
  • a haze meter (turbidity meter) (model: NDH 2000, manufactured by Nippon Denshoku Co., Ltd.) was prepared.
  • the light source was a 5V9W halogen sphere, and the light receiving part was a silicon photocell (with a relative visibility filter).
  • the internal haze was measured under the condition of 23 ° C. and 55% RH.
  • the glass used for measuring the internal haze was MICRO SLIDE GLASS S9213 MATSUNAMI; glycerin was manufactured by Kanto Kagaku deer special grade (purity> 99.0%) and refractive index 1.47.
  • Table 4 shows the production conditions of the obtained optical compensation film, and Table 5 shows the evaluation results.
  • ⁇ SP vs. solvent indicates the absolute value of the difference between the SP value of the solvent and the SP value of the glass transition temperature reducing agent;
  • ⁇ SP vs. resin is that of the cellulose acetate SP value and the glass transition temperature reducing agent.
  • the absolute value of the difference from the SP value is shown.
  • the SP value of each material was calculated based on the calculation method described in References: Basic Science of Coating, Yuji Harada, Tsuji Shoten (1977), p.
  • the optical compensation films of Examples 1 to 13 containing cellulose acetate having a low substitution degree were compared to the optical compensation films of Comparative Examples 1 to 4 containing no low substitution degree component.
  • I 4-10 / I 4-60 is large, and it can be seen that transmitted scattered light is concentrated in the normal direction of the film surface.
  • the optical compensation film of Example 1 containing an additive (compound A) having an SP value closer to the solvent than the resin is the optical compensation film of Example 12 containing an additive (compound E) having an SP value closer to the resin than the solvent. It can be seen that I 4-10 / I 4-60 is larger than that of the compensation film, and transmitted scattered light is concentrated in the normal direction of the film surface.
  • the in-plane retardation R 0 of each of the optical compensation films of Examples 1 to 13 and Comparative Examples 1 to 4 is 40 to 60 nm; the thickness direction retardation Rth is 100 to 170 nm. there were.
  • Polarizer A 120 ⁇ m-thick polyvinyl alcohol film was uniaxially stretched at a temperature of 110 ° C. and a draw ratio of 5 times. The obtained film was immersed in an aqueous solution consisting of 0.075 g of iodine, 5 g of potassium iodide and 100 g of water for 60 seconds, and then immersed in an aqueous solution of 68 ° C. consisting of 3 g of potassium iodide, 7.5 g of boric acid and 100 g of water. I let you. The obtained film was washed with water and dried to obtain a polarizer having a thickness of 25 ⁇ m.
  • a polarizing plate 201 was produced according to the following steps 1 to 5.
  • Step 1 The film 101 obtained in Example 1 was immersed in a 2 mol / L sodium hydroxide solution at 45 ° C. for 45 seconds, then washed with water and dried to saponify the bonding surface with the polarizer.
  • a treated film 101 was obtained.
  • the bonding surface of the Konica Minolta tack KC4UY (cellulose ester film manufactured by Konica Minolta Opto Co., Ltd.) with the polarizer was also saponified.
  • Step 2 The polarizer prepared above was immersed in a polyvinyl alcohol adhesive tank having a solid content of 2% by mass for 1 to 2 seconds.
  • Step 3 After lightly wiping off excess adhesive adhering to the surface of the polarizer, placing the obtained film 101 on one side of the polarizer, and placing Konica Minoltack KC4UY on the other side, A laminate was obtained. Moreover, arrangement
  • FIG. 1 shows an arrangement
  • Step 4 The laminate obtained in Step 3 was bonded at a pressure of 20 to 30 N / cm 2 and a conveyance speed of about 2 m / min.
  • Step 5 The laminated laminate was dried in a dryer at 80 ° C. for 2 minutes to obtain a polarizing plate 201.
  • Polarizing plates 202 to 217 were formed in the same manner except that the film 101 obtained in Example 1 was replaced with the films 102 to 117 obtained in Examples 2 to 13 and Comparative Examples 1 to 4. Obtained.
  • liquid crystal display device (Example 14) As a liquid crystal display device, a 40-inch display KLV-40J3000 made by SONY was prepared. The pair of polarizing plates previously bonded to both sides of the liquid crystal cell was removed, and the polarizing plates 201 prepared above were bonded to both surfaces of the liquid crystal cell, respectively.
  • the lamination of the polarizing plate 201 and the liquid crystal cell was performed so that the film 101 obtained in Example 1 was in contact with the liquid crystal cell.
  • the polarizing plate 201 and the liquid crystal cell were bonded so that the absorption axis of the polarizer of the polarizing plate 201 and the absorption axis of the polarizing plate bonded in advance were in the same direction.
  • Example 15 to 26 and Comparative Examples 5 to 8 A liquid crystal display device was obtained in the same manner as in Example 10 except that the polarizing plate 201 to be bonded to both surfaces of the liquid crystal cell was changed as shown in Table 6.
  • the front contrast (CR0 °), the diagonal contrast (CR30 °), the CR0 ° / CR30 °, and the visual contrast unevenness of the liquid crystal display device were evaluated by the following methods.
  • Oblique contrast oblique white luminance / oblique black luminance iii)
  • the oblique contrast at any 10 points on the display screen of the liquid crystal display device is measured, and the average value thereof is expressed as “oblique contrast (30 ° CR) ”.
  • the visual evaluation of the unevenness of contrast was performed based on the following criteria. ⁇ : There is almost no difference in the appearance of the black display screen between the front direction and the oblique 30 ° direction. ⁇ : A slight difference in the appearance of the black display screen is confirmed between the front direction and the oblique 30 ° direction. A difference in the appearance of the black display screen is confirmed in the oblique 30 ° direction. ⁇ : A clear difference in the appearance of the black display screen is confirmed in the front direction and the oblique 30 ° direction.
  • Table 6 shows the evaluation results of the liquid crystal display devices of Examples 14 to 26 and Comparative Examples 5 to 8.
  • the display devices of Examples 14 to 26 using an optical compensation film having I 4-10 / I 4-60 ⁇ 100 of 97% or more as the protective film F2 or F3 are I 4
  • the difference between the contrast in the front direction and the contrast in the oblique direction is smaller (CR30 ° / CR0 ° is higher) than the display devices of Comparative Examples 5 to 8 where ⁇ 10 / I 4-60 ⁇ 100 is less than 97%. It can be seen that there is little unevenness in contrast between the front direction and the diagonal direction.
  • the display devices of Examples 14 to 22 using an optical compensation film having an I 4-10 / I 4-60 ⁇ 100 of 98% or more are I 4-10 / I 4 Compared to the display devices of Examples 23 to 26 in which ⁇ 60 ⁇ 100 is less than 98%, the difference between the contrast in the front direction and the contrast in the oblique direction is smaller, and the unevenness in contrast between the front direction and the oblique direction is remarkable. It turns out that it is suppressed.
  • the optical compensation film of the present invention contains cellulose diacetate and can reduce unevenness in contrast due to the viewing angle of the display device of the liquid crystal display device.
  • Liquid crystal display device 20 Liquid crystal cell 40 1st polarizing plate 42 1st polarizer 44 Protective film (F1) 46 Protective film (F2) 60 Second polarizing plate 62 Second polarizer 64 Protective film (F3) 66 Protection Film (F4) 80 Backlight

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001151902A (ja) * 1999-11-29 2001-06-05 Konica Corp 光学フィルム及びその製造方法
JP2003279736A (ja) * 2002-03-22 2003-10-02 Fuji Photo Film Co Ltd 光学補償シート、偏光板および液晶表示装置
JP2006182865A (ja) * 2004-12-27 2006-07-13 Konica Minolta Opto Inc ハードコートフィルム、その製造方法、それを用いた偏光板及び表示装置
JP2009265477A (ja) * 2008-04-28 2009-11-12 Konica Minolta Opto Inc 光学補償フィルム、偏光板及び液晶表示装置
JP2010277080A (ja) * 2009-04-30 2010-12-09 Fujifilm Corp 光散乱性基材、光散乱性基材の製造方法、偏光板及び画像表示装置

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007256306A (ja) 2006-03-20 2007-10-04 Fujifilm Corp 光学補償フィルム及びその製造方法、偏光板、並びに液晶表示装置
US20070275188A1 (en) * 2006-05-22 2007-11-29 Fujifilm Corporation Method for producing cellulose acylate film and cellulose acylate film
KR101352529B1 (ko) * 2008-07-10 2014-01-15 에스케이이노베이션 주식회사 셀룰로오스아세테이트 필름
KR101144595B1 (ko) * 2008-07-10 2012-05-11 에스케이이노베이션 주식회사 셀룰로오스아세테이트 필름
JP2011118339A (ja) * 2009-04-28 2011-06-16 Fujifilm Corp セルロースアシレート積層フィルム、セルロースアシレート積層フィルムの製造方法、偏光板および液晶表示装置

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2001151902A (ja) * 1999-11-29 2001-06-05 Konica Corp 光学フィルム及びその製造方法
JP2003279736A (ja) * 2002-03-22 2003-10-02 Fuji Photo Film Co Ltd 光学補償シート、偏光板および液晶表示装置
JP2006182865A (ja) * 2004-12-27 2006-07-13 Konica Minolta Opto Inc ハードコートフィルム、その製造方法、それを用いた偏光板及び表示装置
JP2009265477A (ja) * 2008-04-28 2009-11-12 Konica Minolta Opto Inc 光学補償フィルム、偏光板及び液晶表示装置
JP2010277080A (ja) * 2009-04-30 2010-12-09 Fujifilm Corp 光散乱性基材、光散乱性基材の製造方法、偏光板及び画像表示装置

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