Classifications

• • 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
  • G02F1/133528—Polarisers
• • 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
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B5/00—Optical elements other than lenses
  • G02B5/30—Polarising elements
• • 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
  • G02F1/133504—Diffusing, scattering, diffracting elements
  • G02F1/133507—Films for enhancing the luminance
• • 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
  • G02F1/133634—Birefringent elements, e.g. for optical compensation the refractive index Nz perpendicular to the element surface being different from in-plane refractive indices Nx and Ny, e.g. biaxial or with normal optical axis
• • 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
  • G02F2202/00—Materials and properties
  • G02F2202/40—Materials having a particular birefringence, retardation

Definitions

• the present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device in which luminance loss in an oblique direction is reduced and luminance is increased.
• a polarizing plate mainly used in a liquid crystal display device has a structure in which a polybutyl alcohol film, which is a polarizer, is bonded using two triacetyl cellulose films (hereinafter referred to as TAC films).
• TAC films are characterized by high transparency, small retardation, and easy adhesion to polarizers.
• the TAC film has retardation especially in the thickness direction.
• the linearly polarized light in the oblique direction is converted into elliptically polarized light by the retardation in the thickness direction of the TAC film. This caused a decrease in luminance in an oblique direction due to light absorption by the polarizer.
• Patent Document 1 the problem of color shift is solved by reducing the retardation of the polarizing plate protective film with the same configuration.
• this technology uses a non-cellulosic thermoplastic resin, and its adhesiveness to the polarizer is not sufficient and the adhesive to the polarizer is easily peeled off due to the effect of heat. It was.
• Patent Document 1 Japanese Patent Application Laid-Open No. 2004-271846
• An object of the present invention is to provide a liquid crystal display device that prevents a decrease in light utilization efficiency in an oblique direction in the liquid crystal display device, and in particular, increases the luminance in the oblique direction and expands the viewing angle. .
• One aspect of the present invention for achieving the above object is a liquid crystal display device in which a brightness enhancement film, a polarizing plate (A), a liquid crystal cell, and a polarizing plate (B) are laminated in this order.
• the polarizing plate protective film on the brightness enhancement film side of the plate (A) is a cellulose ester
• the in-plane retardation Ro (550) represented by the following formula (I) is in the range of 0 to 5 nm
• the following formula (III In the liquid crystal display device, the retardation Rt (550) in the thickness direction represented by) is in the range of 15 to 15 nm.
• FIG. 1 shows a configuration of a liquid crystal display device of the present invention and a reference liquid crystal display device used in Examples.
• FIG. 2 is a view of a viewing angle of a comparative example used in Examples.
• FIG. 3 is a view of the viewing angle of the present invention used in Examples.
• FIG. 4 is a diagram comparing viewing angles of the present invention and comparative examples used in Examples. BEST MODE FOR CARRYING OUT THE INVENTION
• Nx and Ny are the maximum and minimum values of refractive index in the film plane, Nz is the refractive index in the thickness direction, d is the film thickness (nm), and Ro (550) and Rt (550 ) Shows retardation at 550nm wavelength]
• the obtained polymer Y contains a polymer Y having a weight average molecular weight of 500 or more and 3000 or less, and the weight average molecular weight of the polymer X is larger than the weight average molecular weight of the polymer Y.
• Rl and R3 each represent H or CH3.
• R2 represents an alkyl group having 1 to 12 carbon atoms or a cycloalkyl group.
• R4 represents one CH2—, one C2H4— or one C3H6—.
• R5 represents H or CH3.
• R6 represents an alkyl group or a cycloalkyl group having 1 to 12 carbon atoms.
• Yb represents a monomer unit copolymerizable with Ya.
• liquid crystal display device that prevents a decrease in light utilization efficiency in the oblique direction in the liquid crystal display device, in particular, increases the luminance in the oblique direction and expands the viewing angle.
• the present invention it was possible to achieve an improvement in luminance by reducing the loss of light absorption by the polarizing plate even in an oblique direction by making the retardation of the cellulose ester film on the backlight side extremely small. .
• the uniformity of brightness could be solved by providing a hard coat layer on the cellulose ester film on the backlight side.
• the liquid crystal display device of the present invention is a liquid crystal display device in which a brightness enhancement film, a polarizing plate (A), a liquid crystal cell, and a polarizing plate (B) are laminated in this order.
• the protective film on the film side is a cellulose ester
• the in-plane retardation Ro (550) represented by the following formula (I) is in the range of 0 to 5 nm
• Chillon Rt (550) is in the range of 15 to 15 nm.
• Nx and Ny are the maximum and minimum values of refractive index in the film plane, Nz is the refractive index in the thickness direction, d is the film thickness (nm), and Ro (550) and Rt (550 ) Shows the retardation at 550nm respectively]
• the linearly polarized light in the oblique direction is converted into elliptically polarized light by the retardation in the thickness direction of the TAC film, and thereby, the light in the oblique direction is absorbed by the polarizer. It caused a decrease in brightness.
• the retardation of the cellulose ester film on the backlight side is made extremely small by making the retardation very small. It has been found that luminance improvement can be achieved without causing light absorption loss due to the polarizer even in the direction of light.
• the cellulose ester film is preferably a cellulose ester, an ethylenically unsaturated monomer Xa having no aromatic ring and no hydrophilic group in the molecule, and an aromatic ring in the molecule and having a hydrophilic group.
• the polymer X and polymer used for the cell mouth ester film on the brightness enhancement film side will be described.
• the polymer X of the present invention includes an ethylenically unsaturated monomer Xa having no aromatic ring and a hydrophilic group in the molecule, and an ethylenically unsaturated monomer Xb having no aromatic ring in the molecule and having a hydrophilic group.
• Rl and R3 each represent H or CH3.
• R2 represents an alkyl group having 1 to 12 carbon atoms or a cycloalkyl group.
• R4 represents one CH2—, one C2H4— or one C3H6—.
• Monomers as monomer units constituting the polymer X of the present invention are listed below, but are not limited thereto.
• the ethylenically unsaturated monomer Xa having no aromatic ring and no hydrophilic group in the molecule includes, for example, methyl acrylate, ethyl acrylate, propyl acrylate (in-), and butyric acrylate (nis-t).
• methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, and n_) are preferred.
• the ethylenically unsaturated monomer Xb having no hydrophilic ring in the molecule and having a hydrophilic group is preferably acrylic acid or methacrylic acid ester as a monomer unit having a hydroxyl group.
• the polymer X is synthesized by copolymerization using the hydrophobic monomer Xa and the hydrophilic monomer Xb.
• the ratio of the hydrophobic monomer Xa to the hydrophilic monomer Xb used in the synthesis is preferably 99 ::! To 65:35, more preferably 95: 5 to 75:25.
• the ratio of the hydrophobic monomer Xa is large, the compatibility with the cellulose ester is improved, but the retardation value Rt in the film thickness direction is increased.
• the ratio of the hydrophilic monomer Xb is in the above range because the haze of the cellulose ester film is lowered.
• Xc is not particularly limited as long as it is a copolymerizable ethylenically unsaturated monomer other than Xa and Xb, but preferably does not have an aromatic ring.
• P of Xc is 0-10.
• Xc may be a plurality of monomer units.
• the hydroxyl value of the polymer X is preferably 30 to 150 [mgKOH / g].
• This measurement conforms to JIS K 0070 (1992).
• This hydroxyl value is defined as the number of mg of potassium hydroxide required to neutralize acetic acid bound to a hydroxyl group when sample lg is acetylated.
• sample Xg (about lg) is precisely weighed in a flask, and 20 ml of acetylating reagent (20 ml of acetic anhydride added to pyridine to make 400 ml) is accurately added. Attach an air cooling tube to the mouth of the flask, and heat at 95-: 100 ° C glycerin bath.
• Hydroxyl value ⁇ (B_C) X f X 28. 05 / X ⁇ + D (where B is the amount of 0.5 mol ZL potassium hydroxide ethanol solution used in the blank test (ml), C is Amount of 0.5 mol ZL of potassium hydroxide ethanol solution used for titration (ml), f is a factor of 0.5 mol / L potassium hydroxide ethanol solution, D is acid value, and 28.05 is potassium hydroxide lmol represents 56.11 1/2)
• the molecular weight of the polymer X has a weight average molecular weight of 2,000 to 30,000, more preferably 3,000 to 25,000.
• the dimensional change of the polarizing plate under high temperature and high humidity is small. There are advantages and preferred.
• the weight average molecular weight is 30000 or less, compatibility with the cellulose ester is good, bleeding out under high temperature and high humidity is reduced, haze is low, and a film can be formed.
• the weight average molecular weight of the polymer X of the present invention can be adjusted by a known molecular weight adjusting method.
• a molecular weight adjusting method include a method of adding a chain transfer agent such as carbon tetrachloride, lauryl mercaptan, octyl thioglycolate, and the like.
• the polymerization temperature is usually from room temperature to 130 ° C, preferably from 50 ° C to 100 ° C. This temperature or the polymerization reaction time can be adjusted.
• the weight average molecular weight can be measured by the following method.
• the weight average molecular weight is measured using gel permeation chromatography.
• the polymer ⁇ of the present invention is a polymer having a weight average molecular weight of 500 to 3,000 obtained by polymerizing an ethylenically unsaturated monomer Ya having no aromatic ring, and represented by the following general formula (2): Preferred are the polymers represented. Polymers with a weight average molecular weight of less than 500 are difficult to produce due to the large amount of residual monomers. Is preferable for obtaining the effects of the present invention because the retardation Rt tends to decrease.
• R5 represents H or CH3.
• R6 represents an alkyl group or a cycloalkyl group having 1 to 12 carbon atoms.
• Yb represents a monomer unit copolymerizable with Ya.
• Yb is not particularly limited as long as it is an ethylenically unsaturated monomer copolymerizable with Ya.
• Y b may be plural.
• q is preferably 0-30.
• Ethylenically unsaturated monomer Ya constituting polymer Y obtained by polymerizing ethylenically unsaturated monomer having no aromatic ring Ya is an acrylate ester such as methyl acrylate, ethyl acrylate, acrylic acid Propyl (in-), butyl acrylate (n- ist), pentyl acrylate (nis), hexyl acrylate (ni), heptyl acrylate (ni), octyl acrylate (ni)
• Yb is not particularly limited as long as it is an ethylenically unsaturated monomer copolymerizable with Ya, but as the butyl ester, for example, butyl acetate, butyl propionate, butyl butyrate, valerate valerate, and pivalin.
• Yb may be plural.
• the acrylic polymer is a homopolymer or copolymer of the above-mentioned monomers, but preferably contains at least 30% by mass of the methyl acrylate ester unit and 40% by mass of the methyl methacrylate monomer unit. It is preferable to have more than%. In particular, a homopolymer of methyl acrylate or methyl methacrylate is preferred.
• Examples include a compound having a single thiol group and a secondary hydroxyl group as disclosed in JP 2000-344823, or a bulk polymerization method using a polymerization catalyst in which the compound and an organometallic compound are used in combination. Any of these is preferably used in the present invention. In particular, the method described in the publication is preferred.
• the polymer obtained by polymerizing the ethylenically unsaturated monomer and the acrylic polymer are both excellent in compatibility with the cellulose ester, excellent in productivity without evaporation and volatilization, and as a protective film for a polarizing plate. It has excellent dimensional stability, low moisture permeability, good retentivity.
• the content of the polymer X and the polymer Y in the cellulose ester film is preferably in a range satisfying the following formulas (i) and (ii). If the content of polymer X is Xg (mass%) and the content of polymer ⁇ is Y g (mass%),
• a preferable range of the formula (i) is 10 to 25% by mass.
• the polymer X and the polymer Y can be added directly to a dope solution after being dissolved in an organic solvent that dissolves cellulose ester in advance, or can be directly added and dissolved as a material constituting the dope solution described later.
• the cellulose ester used in the present invention is preferably a lower fatty acid ester of cellulose.
• the lower fatty acid in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms.
• mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate petitate as described in US Pat. No. 2,319,052 can be used.
• the lower fatty acid esters of cellulose that are particularly preferably used are cellulose triacetate and cellulose acetate propionate. These senole mouth esters can be used alone or in combination.
• cellulose triacetate those having an average degree of acetylation (bound acetic acid amount) of 54.0 to 62.5% are preferably used, and more preferably an average degree of acetylation of 58.0 to 62.5. % Of cellulose triacetate.
• Preferred cellulose esters other than cellulose triacetate have an acyl group having 2 to 4 carbon atoms as a substituent, the substitution degree of the acetyl group is X, and the substitution degree of the propionyl group is Y, It is a cellulose ester that simultaneously satisfies the formulas (1) and (2).
• cellulose acetate propionate of 1. 0 ⁇ 2.95 and 0.1 ⁇ 2.0 is preferable.
• the portion not substituted with an asinole group is usually present as a hydroxyl group It is.
• a cellulose ester synthesized using cotton linter, wood pulp, kenaf or the like as a raw material can be used alone or in combination.
• cotton linter hereinafter sometimes referred to simply as linter
• linter is preferred to use a synthesized cellulose ester alone or in a mixture.
• Cellulose ester has a number average molecular weight (Mn) of 60,000 to 200 000 of strength S, preferably 80,000 to : 170000 of strength S, more preferably 0
• the molecular weight distribution Mw / Mn is preferably in the range of 1.0 force to 5.0 but more preferably in the range of 1.0 force to 3.0.
• the dope used for forming the cellulose ester film of the present invention may contain a conventionally used low molecular plasticizer, low molecular ultraviolet absorber or low molecular antioxidant. If necessary, a small amount of low molecular weight plasticizer or low molecular weight UV absorber may be added to the extent that it does not precipitate. However, as the plasticizer added, the retardation Rt increases. Shinare, materials such as those that do not have an aromatic ring, materials are preferred.
• plasticizers can be used in the cellulose ester film of the present invention.
• Phosphate ester plasticizers specifically, phosphoric acid alkyl esters such as triacetyl phosphate and tributyl phosphate, phosphoric acid cycloalkyl esters such as tricyclopentyl phosphate and cyclohexyl phosphate, and triphenyl Phosphate such as phosphate, tricresinole phosphate, cresyl phenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, trinaphthyl phosphate, trixylyl phosphate, tris ortho-biphenyl phosphate And aryl ester.
• phosphoric acid alkyl esters such as triacetyl phosphate and tributyl phosphate
• phosphoric acid cycloalkyl esters such as tricyclopentyl phosphate
• alkylene bis (diaryl phosphate) such as ethylene bis (dimethyl phosphate), butylene bis (diethyl phosphate), alkylene bis (dialkyl phosphate), ethylene bis (diphenyl phosphate), propylene bis (dinaphthyl phosphate), etc.
• substituents may be the same or different, and may be further substituted.
• a mixture of an alkyl group, a cycloalkyl group, and an aryl group may be used, and substituents may be covalently bonded.
• phosphate ester Part of polymer or part of molecular structure of additives such as antioxidant, acid scavenger, UV absorber etc. Even if it has been introduced to.
• additives such as antioxidant, acid scavenger, UV absorber etc.
• phosphate aryl ester and arylene bis (diaryl phosphate) are preferable.
• triphenyl phosphate and phenyl bis (diphenol phosphate) are preferable.
• Ethylene glycol ester plasticity Ij Specifically, ethylene glycol alkyl ester plasticizers such as ethylene glycol diacetate and ethylene glycol dibutyrate, ethylene glycol dicyclopropylcarboxylate, ethylene glycol Examples thereof include ethylene glycol cycloalkyl ester-based plasticizers such as dicyclohexylcarboxylate-based plasticity lj, ethylene glycol dibenzoate, ethylene glycol di4-methylbenzoate and the like. These alkylate groups, cycloalkylate groups, and arylate groups may be the same or different, and may be further substituted.
• ethylene glycol ester may have a substituted partial structure strength of an ethylene glycol ester. It may be part of a polymer or may be regularly pendant. Also, an antioxidant, an acid scavenger, an ultraviolet absorber, etc. It may be introduced into part of the molecular structure of the additive.
• Glycerin ester plasticizers specifically, triacetin, tributyrin, glycerin di Glycerin alkyl esters such as acetate caprylate and glycerinate propionate, glycerin cycloalkyl esters such as glycerin tricyclopropyl carboxylate and glycerin tricyclohexylcarboxylate, glycerin tribenzoate, glycerin 4_methylbenzoate, etc.
• Diglycerin alkyl esters such as glycerin aryl ester, diglycerin tetraacetylate, diglycerin tetrapropionate, diglyceryl acetate tricaprylate, diglycerin tetralaurate, diglycerin tetracyclobutylcarboxylate, diglycerin tetra Diglycerin cycloalkyl esters such as cyclopentylcarboxylate, diglycerin tetrabenzoate, diglycerin 3-methyl Diglycerol ⁇ reel esters such as Rubenzoeto like.
• alkylate groups, cycloalkyl carboxylate groups, and arylate groups may be the same or different, and may be further substituted. Further, a mixture of alkylate group, cycloalkyl carboxylate group and arylate group may be used, and these substituents may be bonded by a covalent bond. Furthermore, glycerin ester and diglycerin part may be substituted glycerin ester, diglycerin ester partial structural strength part of polymer, or may be regularly bent, also antioxidant, acid scavenger Introduced into part of the molecular structure of additives such as UV absorbers.
• Polyhydric alcohol ester plasticity lj Specific examples include polyhydric alcohol ester plasticizers described in paragraphs 30 to 33 of JP-A No. 2003-12823.
• alkylate group, cycloalkylcarboxylate group and arylate group may be the same or different, and may be further substituted. Also, a mixture of alkylate group, cycloalkylcarboxylate group, and arylate group may be used, and these substituents may be bonded by a covalent bond. Furthermore, the polyhydric alcohol part may be substituted, or it may be part of the polyhydric alcohol partial structural force polymer or may be regularly pendant. Also, an antioxidant, an acid scavenger, Introduced into a part of the molecular structure of additives such as UV absorbers.
• Dicarboxylic acid ester plasticizer Specifically, alkyl dicarboxylic acid alkyl ester plasticizers such as didodecyl malonate (C1), dioctyl adipate (C4), dibutyl sebacate (C8), Dicyclopentyl succinate, dicyclohexyl ajipe Alkyl dicarboxylic acid alkyl ester plasticizers such as diphenyl succinates, alkyl dicarboxylic acid aryl ester plasticizers such as di-4-methylphenyl daltalate, dihexyl _ 1,4-cyclo Hexane dicarboxylate, didecyl bicyclo [2.2.1] heptane-1,2-dicarboxylate and other cycloalkyl dicarboxylic acid alkyl ester plasticizers, dicyclohexyl _ 1,2-cyclobutane dicarbo Plastics of cycloalkyl dicarbox
• alkyl dicarboxylic acid alkyl ester plasticizers dicyclopropyl phthalate, dicyclohexyl
• examples include arylene dicarboxylic acid cycloalkyl ester plasticizers such as phthalate, and aryldicarboxylic acid aryl ester plasticizers such as diphenyl phthalate and di 4 methylphenyl phthalate.
• alkoxy groups and cycloalkoxy groups may be the same or different, and may be mono-substituted. These substituents may be further substituted.
• the alkyl group and cycloalkyl group may be mixed, or these substituents may be covalently bonded.
• aromatic ring of phthalic acid is substituted, and a polymer such as a good dimer, trimer, or tetramer may be used.
• partial structural strength of phthalate ester may be part of the polymer or may be regularly pendant to the polymer. Introduced into part of the molecular structure of additives such as antioxidants, acid scavengers, UV absorbers, etc. It ’s been good.
• Polyvalent carboxylic acid ester plasticizer Specifically, tridodecyl tri force ruvalate, tributyl mono meso-butane 1, 2, 3, 4-tetracarboxylate, etc.
• Plasticizers such as tricyclohexenoretricanorevalate, tricyclopropyl_2-hydroxy-1, 2,3_propanetricarboxylate, and other polyvalent carboxylic acid cycloalkyl esters based on plastic lj, triphenyl 2-hydroxy_1 , 2, 3 —Propane tricarboxylate, tetra 3 _methylphenyltetrahydrofuran 1, 2, 4, 4, 5-tetracarboxylate, etc.
• Cycloalkyl polycarboxylic acid alkyl ester plasticizers such as lj, tetrahexyl _ 1, 2, 3, 4-cyclobutane tetracarboxylate, tetrabutyl _ 1, 2, 3, 4-cyclopentane tetracarboxylate , Polycyclopropyl _ 1, 2, 3, 4-cyclobutane tetracarboxylate, tricyclohexyl mono 1, 3, 5-cyclohexyl tricarboxylate, etc.
• Cycloalkyl polycarboxylic acids such as triphenyl-1,3,5-cyclohexyltricarboxylate, hex-4-methylphenyl-1,2,3,4,5,6-cyclohexylhexcarboxylate Aleyl ester plasticizer, tridodecylbenzene 1, 2, 4-tricarboxylate, tetraoctylbenzene 1, 2, 4, 5 tet Allyl polycarboxylic acid alkyl ester plasticizers such as carboxylate, tricyclopentylbenzene 1, 3, 5-tricarboxylate, tetracyclohexylbenzene 1, 2, 3, 5-tetra force ruboxylate, etc.
• Aryl polycarboxylic acid cycloalkyl ester-based plasticizers Triphenylbenzene 1, 3, 5-tetracartoxylate, hexa 4 Methylphenylbenzene 1, 2, 3, 4, 5, 6 Hexacarboxylate And arylene polyvalent carboxylic acid ester plasticizers. These alkoxy groups and cycloalkoxy groups may be the same or different, and may be mono-substituted. These substituents may be further substituted. The alkyl group and cycloalkyl group may be mixed, or these substituents may be covalently bonded.
• the aromatic ring of phthalic acid may be substituted, and a multimer such as a dimer, trimer or tetramer may be used.
• the partial structure of the phthalate ester is introduced into part of the molecular structure of additives such as antioxidants, acid scavengers, UV absorbers, etc., which may be partly pendant into the polymer. It may be done.
• the polarizing plate protective film and other films used in the liquid crystal image display device contain an ultraviolet absorber, and the ultraviolet absorber serves to prevent deterioration of the liquid crystal and the polarizing film when used outdoors.
• an ultraviolet absorber is preferably used.
• Ultraviolet absorbers have excellent performance in absorbing ultraviolet light with a wavelength of 370 nm or less, and have a transmittance of 50% or less with as little absorption of visible light as possible with a wavelength of 400 nm or more. It is preferable that it is above.
• the transmittance at a wavelength of 370 nm is preferably 10% or less, more preferably 5% or less.
• ultraviolet absorbers examples include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, and triazines. Benzotriazole compounds, which are less colored, are preferred. Benzotriazole-based UV absorbers and benzotriazole-based UV absorbers, which have stability against light, are preferred, and benzotriazole-based UV absorbers with less unwanted coloration are preferred.
• TINUVIN109 referred to as UV-1
• TINUVIN171, TIN UVIN326, TINUVIN327, TINUVIN328, etc. manufactured by Ciba 'Specialty' Chemicals Co., Ltd.
• the plasticizer it may deposit on the web during film formation or volatilize, so the amount added is:! -10 mass%.
• the cellulose ester film contains a high-molecular ultraviolet absorber that is less likely to precipitate than the low-molecular-weight ultraviolet absorber together with the polymer according to the present invention.
• UV rays can be sufficiently cut in a stable state without impairing retention, moisture permeability, etc. and without phase separation in the film.
• a polymer ultraviolet absorber described in JP-A-6-148430 and a polymer containing an ultraviolet absorber monomer can be used without limitation.
• the present invention contains a UV-absorbing copolymer polymer (sometimes referred to as a polymer UV absorber or a polymer UV agent) synthesized from an UV-absorbing monomer represented by the following general formula (3). And then, it ’s better to be.
• a UV-absorbing copolymer polymer sometimes referred to as a polymer UV absorber or a polymer UV agent
• n represents an integer of 0 to 3
• R to R represent a hydrogen atom, a halogen atom, or a substituent.
• X represents —COO—, —CONR—, —OCO—, —NR C ⁇ —, and R and R represent hydrogen.
• R 7 7 6 7 represents an atom, an alkyl group, or an aryl group.
• the group represented by R is a polymerizable group.
• n represents an integer of 0 to 3, and when n is 2 or more, a plurality of R
• 5 may be the same or different and may be linked to each other to form a 5- to 7-membered ring.
• R to R each represents a hydrogen atom, a halogen atom or a substituent.
• halogen atom As halogen atom
• Examples thereof include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom and a chlorine atom are preferable.
• the substituent include an alkyl group (for example, a methyl group, an ethyl group, an isopropyl group, a hydroxyethyl group, a methoxymethylol group, a trifluoromethyl group, a tbutyl group, etc.), an alkenyl group (for example, a bur group, an aryl group).
• R to R may have a substituent, and adjacent R to R are connected to each other to form a 5- to 7-membered
• a ring may be formed.
• R represents a hydrogen atom, an alkyl group, a cycloalkyl group, an alkenyl group, or an alkynyl group.
• alkyl group examples include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, an amyl group, an isoamyl group, and a hexyl group.
• the alkyl group may further have a halogen atom or a substituent, and examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
• substituents examples include , An acyl group (eg, acetyl group, propanol group, butyroyl group, etc.), an alkoxy group (eg, methoxy group, ethoxy group, isopropoxy group, n-butoxy group, etc.), amino group, alkylamino group (eg, methylamino group) Group, ethynoleamino group, jetylamino group, etc.), acylenoamino group (eg, acetylamino group, propionylamino group, etc.), hydroxyl group, cyano group, strong rubamoyl group (eg, methylolene ruberamoyl group, ethylcarbamoyl group, dimethylcarbamoyl group) Group), an acyloxy group (for example, an acetoxy group, piva) Etc. Iruokishi group), an alkoxycarbonyl group (e.g.,
• cycloalkyl group examples include saturated cyclic hydrocarbons such as a cyclopentyl group, a cyclohexyl group, a nonenobonenyl group, and an adamantyl group, which may be unsubstituted or substituted. good.
• Examples of the alkenyl group include a vinyl group, an aryl group, and a 1-methyl-2-propenyl group.
• a butyl group and a 1_methyl_2_propenyl group are preferable.
• the alkynyl group includes, for example, an ether group, a butazyl group, a propargyl group, a 1-methyl_2_propynyl group, a 2-butul group, a 1,1-dimethyl_2_propynyl group, and the like. Is an ethur group or a propargyl group.
• X represents 1 CO 0, -CONR-, 1 OC 0 1 or 1 NR CO-.
• R represents a hydrogen atom, an alkyl group, or a cycloalkyl group.
• the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, An amyl group, an isoamyl group, a hexyl group, etc. are mentioned.
• examples of the halogen atom that may further have a halogen atom and a substituent include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom.
• Examples of the substituent include , An acyl group (for example, acetyl group, a propanol group, a propyloyl group, etc.), an alkoxy group (for example, a methoxy group, an ethoxy group, an isopropoxy group, an n-butoxy group, etc.), an amino group, an alkylamino group (for example, Methylamino group, ethylamino group, jetylamino group, etc.), anilino group (for example, anilino group, N-methylanilino group, etc.), asinoleamino group (for example, acetylylamino group, propionylamino group, etc.), hydroxynore group, cyano group, Strong rubamoyl groups (eg methylcarbamoyl group, ethylcarbamoyl group, dimethylcarbamoyl group) Etc.
• An acyl group for
• Ashiruokishi group e.g., Asetokishi group, etc. Pibaroiruokishi group
• alkoxides aryloxycarbonyl group e.g., methoxycarbonyl, ethoxycarbonyl, etc.
• cycloalkyl group examples include saturated cyclic hydrocarbons such as a cyclopentyl group, a cyclohexyl group, a nonenobonenyl group, and an adamantyl group, which may be unsubstituted or substituted. good.
• the polymerizable group in the present invention means an unsaturated ethylene polymerizable group or a bifunctional polycondensable group, and preferably an unsaturated ethylene polymerizable group.
• Specific examples of the unsaturated ethylene-based polymerizable group include a buyl group, a allyl group, an allyloyl group, a methacryloyl group, a styryl group, an acrylamide group, a methacrylamide group, a cyanuric acid group, and 2-cyanacrylo group.
• Forces such as xyl group, 1,2_epoxy group, butyl ether group, etc.
• Preferred are vinyl group, attalyloyl group, methacryloyl group acrylamide group and methacrylamide group.
• the term “having a polymerizable group as a partial structure” means that the polymerizable group is bonded directly or via a divalent or higher valent linking group.
• the divalent or higher valent linking group include, for example, an alkylene group.
• the polymer derived from the UV-absorbing monomer preferably has a weight average molecular weight of 2000 or more and 300000 or less, more preferably 5000 or more and 20000 or less.
• the weight average molecular weight of the ultraviolet-absorbing copolymer used in the present invention can be adjusted by a known molecular weight adjusting method.
• a molecular weight adjusting method include a method of adding a chain transfer agent such as tetrasalt ⁇ carbon, lauryl mercabtan, octyl thioglycolate, and the like.
• the polymerization temperature is usually from room temperature to 130 ° C, preferably from 50 ° C to 100 ° C.
• the ultraviolet-absorbing copolymer used in the present invention may be a homopolymer of only an ultraviolet-absorbing monomer or a copolymer with another polymerizable monomer.
• examples of other polymerizable monomers that can be polymerized include styrene derivatives (for example, styrene, trimethylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinylnaphthalene, etc.), acrylic ester derivatives.
• methacrylate ester derivatives for example, Methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, methacrylate Acid i- butyl, t- butyl methacrylate, Okuchiru methacrylate, hexyl or the like to the main methacrylic acid cycloalkyl
• alkyl Bulle ethers e.g., methyl vinyl ether, E chill Bulle ether, butyl Bulle ether
• alkyl Bulle Este Nole eg, formate, acetate, butyrate, caproate, stearate
• crotonic acid maleic acid
• the hydrophilic ethylenically unsaturated monomer is not particularly limited as long as it is hydrophilic and has an unsaturated double bond that can be polymerized in the molecule, and examples thereof include acrylic acid and methacrylic acid.
• An unsaturated carboxylic acid, or an acrylic acid or methacrylic acid ester having a hydroxyl group or an ether bond for example, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, tetrahydrofurfuryl methacrylate, acrylic acid 2 —Hydroxychetyl, 2-hydroxypropyl acrylate, 2,3-dihydroxy 2-methylpropyl methacrylate, tetrahydrofurfuryl acrylate, 2-ethoxyethyl acrylate, diethylene glycol ethoxylate acrylate, 3-methoxybutyl acrylate, etc.) Acrylamide, N, N Methyl (meth) (N-substituted) acrylamide, (meth) acrylamide, N Bulle pyrrolidone, N Bulle O hexa sledding pyrrolidone, and the like.
• hydrophilic ethylenically unsaturated monomer examples include 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, and (meth) acrylate having a hydroxyl group or a carboxyl group in the molecule. Particularly preferred are 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate.
• These polymerizable monomers can be used alone or in combination of two or more to be copolymerized with the ultraviolet absorbing monomer.
• the polymerization method of the ultraviolet-absorbing copolymer used in the present invention is not particularly limited, and conventionally known methods can be widely employed, and examples thereof include radical polymerization, anion polymerization, and cationic polymerization.
• examples of the initiator for the radical polymerization method include azo compounds and peroxides, and include azobisisobutyronitrile (AIBN), azobisiso Ptylic acid diester derivatives, benzoyl peroxide, hydrogen peroxide and the like.
• the polymerization solvent is not particularly limited.
• aromatic hydrocarbon solvents such as toluene and black benzene
• halogenated hydrocarbon solvents such as dichloroethane and chloroform
• ether solvents such as tetrahydrofuran and dioxane
• amide solvents such as dimethylformamide
• alcohol solvents such as methanol
• ester solvents such as methyl acetate and ethyl acetate
• ketone solvents such as acetone, cyclohexanone, and methyl ethyl ketone
• water solvents such as water solvents.
• solution polymerization that polymerizes in a homogeneous system precipitation polymerization that precipitates the produced polymer, emulsion polymerization that polymerizes in a micelle state, and suspension polymerization that polymerizes in a suspension state can also be performed.
• UV-absorbing latex obtained by emulsion polymerization is not suitable for use as an optical film.
• the use ratio of the above-mentioned UV-absorbing monomer, polymerizable monomer copolymerizable therewith and hydrophilic ethylenically unsaturated monomer is determined by the compatibility of the resulting UV-absorbing copolymer polymer with other transparent polymers. It is appropriately selected in consideration of the influence on the transparency and mechanical strength of the optical film.
• the content of the ultraviolet absorbing monomer in the polymer derived from the ultraviolet absorbing monomer is preferably 1 to 70 mass%, more preferably 5 to 60 mass%.
• the content of the UV monomer in the UV light absorbing polymer is less than 1% by mass, a large amount of the UV absorbing polymer must be used when trying to satisfy the desired UV absorbing performance, resulting in an increase in haze or Transparency decreases due to precipitation, etc., which causes a decrease in film strength.
• the content of the ultraviolet monomer in the ultraviolet absorbing polymer is less than 70% by mass, the compatibility with the cellulose ester is improved and a transparent optical film is easily obtained.
• the solubility with respect to a solvent becomes high, which is preferable in terms of workability and productivity in film production.
• the hydrophilic ethylenically unsaturated monomer is preferably contained in the UV-absorbing copolymer in an amount of 0.:! To 50% by mass. When the amount is less than 1% by mass, the effect of improving the compatibility with the hydrophilic ethylenically unsaturated monomer does not appear, and when it exceeds 50% by mass, it is difficult to isolate and purify the copolymer. A more preferable content of the hydrophilic ethylenically unsaturated monomer is 0.5 to 20% by mass. If the UV-absorbing monomer itself is substituted with a hydrophilic group, it is hydrophilic The total content of the ultraviolet absorbing monomer and the hydrophilic ethylenically unsaturated monomer is preferably within the above range.
• the UV-absorbing monomer and the (non) hydrophilic ethylenically unsaturated monomer may be copolymerized by mixing two or more of each.
• the ultraviolet absorber, the ultraviolet absorbing monomer and the intermediate thereof used in the present invention can be synthesized with reference to known literature.
• the ultraviolet absorbent and ultraviolet absorbent polymer used in the present invention may be used together with a low molecular weight compound, a high molecular weight compound, an inorganic compound, or the like, if necessary, when mixed with another transparent polymer. You can also.
• ultraviolet absorbers used in the present invention and others It is also possible to mix the low molecular weight UV absorber with other transparent polymer at the same time, or simultaneously mix the UV light absorbing polymer and other low molecular weight UV absorber used in the present invention with another transparent polymer. This is one of the preferred embodiments.
• additives such as an antioxidant, a plasticizer, and a flame retardant are mixed at the same time.
• the method for adding the ultraviolet absorbent and the ultraviolet absorbing polymer used in the present invention to the cellulose ester film may be contained in the cellulose ester film or coated on the cellulose ester film. ,. When it is contained in the cellulose ester film, it may be added directly or in-line. In-line addition is a method of dissolving in advance in an organic solvent (for example, methanol, ethanol, methylene chloride, etc.) and then adding it to the dope composition with an in-line mixer or the like.
• an organic solvent for example, methanol, ethanol, methylene chloride, etc.
• the amount of the ultraviolet absorber and the ultraviolet absorbing polymer used in the present invention is not uniform depending on the type of compound, the conditions of use, etc., but in the case of an ultraviolet absorber, it is necessary to use a cellulose styrene ester. 0.2 to 3. Og force S per refinolem lm 2, preferably 0.4 to 2.0 force S, more preferably 0.5 to 1.5. Further, in the case of an ultraviolet absorbing polymer, 0.6 to 9. Og force S is preferable per cell mouth estenolefinolem lm 2 , 1.2 to 6.0 force S is more preferable, 1.5 to 3.0 is particularly preferred.
• the transmittance at a wavelength of 380 nm is particularly preferably 8% or less, more preferably 4% or less, and further preferably 1% or less.
• UV absorber is preferably used as a commercially available polymer ultraviolet absorber. Two or more ultraviolet absorbers may be used.
• the UV absorber can be added to the dope using alcohol or The ultraviolet absorber may be dissolved in an organic solvent such as methylene chloride, dioxolane, methyl acetate, etc., or added directly or during the dope composition.
• the cellulose ester film of the present invention may contain an antioxidant.
• it may contain a peroxide decomposing agent, a radical chain inhibitor, a metal deactivator or an acid scavenger as described in JP-A-5- 197073.
• the amount of these compounds added is lppm to 1.0 in terms of mass ratio with respect to the cellulose ester. /. ⁇ , 10 ⁇ :! OOOppm more preferred.
• the fine particle matting agent preferably contains a fine particle matting agent in the cellulose ester film, for example, silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin. It is preferable to include inorganic fine particles such as talc, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, and crosslinked polymer fine particles. Among them, silicon dioxide is preferable because it can reduce the haze of the film.
• the average particle size of the secondary particles of the fine particles is in the range of 0.01 to 1.0 / im, and the content thereof is preferably 0.005 to 0.3% by mass with respect to the cellulose ester.
• fine particles such as silicon dioxide are surface-treated with an organic material, but such a material is preferable because the haze of the film can be reduced.
• Preferred organic substances for the surface treatment include halosilanes, alkoxysilanes (particularly alkoxysilanes having a methyl group), silazane, and siloxane.
• These matting agents may be used in combination of two or more. When two or more types are used in combination, they can be mixed and used at an arbitrary ratio. In this case, matting agents with different average particle sizes and materials, for example, AEROSIL 200V and R972V in a mass ratio of 0.1: 99. Can be used in the range of 9 to 99.9 to 0.1.
• a method for preparing a cellulose ester dope in the present invention will be described.
• flaky cellulose ester is dissolved in an organic solvent mainly composed of a good solvent for cellulose ester while stirring to form a dope.
• an organic solvent mainly composed of a good solvent for cellulose ester while stirring to form a dope.
• a method performed at normal pressure a method performed at a temperature lower than the boiling point of the main solvent, a method performed at a pressure higher than the boiling point of the main solvent, JP-A-9-95544, JP-A-9-95557, or JP-A-9-95538
• dissolution methods such as a method using a cooling dissolution method as described in the gazette and a method using high pressure as described in JP-A-11-21379.
• the dope After dissolution, the dope is filtered with a filter medium, defoamed, and sent to the next process with a pump.
• concentration of cellulose ester in the dope is about 10 to 35% by mass. More preferably, it is 15-25 mass%.
• the addition method such as adding after dissolving the polymer in an organic solvent in advance or adding directly to the cellulose ester dope can be carried out without limitation. In this case, the polymer is added so that it does not become cloudy or phase-separated in the dope.
• the amount of the additive is as described above.
• Organic solvents as good solvents for cellulose esters include methyl acetate, ethyl acetate, amyl acetate, ethyl formate, acetone, cyclohexanone, methyl acetoacetate, tetrahydrofuran, 1,3-dioxolan, 4-methylolone.
• Examples of pentafluoride include 1-propanol, nitroethane, 2_pyrrolidone, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, methylene chloride, bromopropane, and the like.
• the organic solvent used for the dope according to the present invention is preferably a mixture of a good and poor cellulose ester solvent.
• the preferable range of the mixing ratio of the good solvent and the poor solvent is 70 to 98% by mass for the good solvent and 2 to 30% by mass for the poor solvent.
• the poor solvent used for the dope according to the present invention is not particularly limited.
• methanol, ethanol, n-butanol, cyclohexane, cyclohexanone and the like can be preferably used.
• a good solvent of cellulose ester for the selection of the organic solvent.
• a low molecular weight plasticizer it can be carried out by an ordinary addition method, and it can be added directly into the dope, or it can be dissolved in an organic solvent and then poured into the dope.
• the cellulose ester dope and various additives are added in-line to a solution in which a small amount of cellulose ester is dissolved and mixed. It can also be performed and is preferable.
• an in-line mixer such as a static mixer SWJ (Toray Static In-Pipe Mixer Hi-Mixer) (manufactured by Toray Engineering).
• SWJ Toray Static In-Pipe Mixer Hi-Mixer
• the type of pressurized container that is preferred to be applied to a dope obtained by concentrating and dissolving cellulose ester under high pressure can withstand a predetermined pressure, especially where it is questioned. It only needs to be able to stir.
• the cellulose ester dope must be filtered to remove foreign matter, particularly foreign matter that would be recognized as an image in a liquid crystal image display device. It can be said that the quality of the polarizing plate protective film is determined by this filtration.
• Filter media used for filtration preferably have a low absolute filtration accuracy. However, if the absolute filtration accuracy is too low, the filter media may become clogged and the filter media must be replaced frequently, which reduces productivity. There is a problem of making it. Therefore, is the cellulose ester-doped filter medium of the present invention absolutely?
• Consideration accuracy is preferably less than 0.008 mm, more preferably in the range of 0.001 to 0.008 mm, more preferably in the range of 0.003 to 0.006 mm.
• material of the filter medium there are no particular restrictions on the material of the filter medium, but ordinary filter media can be used. However, filter fibers made of plastic fibers such as polypropylene and Teflon (registered trademark), and metal filter media such as stainless steel fibers are used to remove fibers. This is preferable. Filtration of the cellulose ester dope of the present invention is performed by a usual method.
• the method of filtering while heating under pressure at a temperature that is above the boiling point of the solvent at normal pressure and that the solvent does not boil is the difference in pressure before and after filtration (hereinafter sometimes referred to as filtration pressure).
• the rise is preferably small.
• the preferred temperature range is 45-120 ° C, more preferably 45-70 ° C, and even more preferably 45-55 ° C.
• a smaller filtration pressure is preferable.
• the filtration pressure is preferably 1.6 X 10 6 Pa or less 1. More preferably 2 X 10 6 Pa or less 1. More preferably 0 X 10 6 Pa or less. ,.
• a foreign matter failure (hereinafter sometimes referred to as a bright spot) may occur.
• a cellulose ester film is placed between two polarizing plates in a crossed state (crossed Nicols)
• light is irradiated from one side and observed with an optical microscope (50x) from the opposite side, a normal cellulose ester film is obtained. If this is the case, the light is blocked, and nothing black can be seen. However, if there is a foreign object, the light leaks out and appears to shine like a spot.
• the bright spot diameter means a diameter measured by approximating the bright spot to a perfect circle. There are no practical problems if the above-mentioned diameter is 400 pieces / cm 2 or less, but the bright spot is preferably 300 pieces / cm 2 or less, more preferably 200 pieces / cm 2 or less. In order to reduce the number and size of such bright spots, it is necessary to sufficiently filter fine foreign matters.
• a method in which a pulverized cellulose ester film once formed is re-added in a proportion in the dope and used as a raw material for cellulose ester and its additive is a brilliant method. Since the point can be reduced, it can be preferably used.
• the metal support is an endless metal belt or a rotating metal drum that moves indefinitely, and its surface is a mirror surface.
• the casting step is a step of feeding the dope as described above to a pressure die through a pressure type quantitative gear pump, and casting the dope from the pressure die onto the metal support at the casting position.
• Other casting methods include a doctor blade method in which the film thickness of the cast dope film is adjusted with a blade, or a river with a reverse rotating roll.
• a pressure die that can adjust the slit shape of the die part and easily make the film thickness uniform is preferable.
• Force for the Q pressure die any force having a coat hanger die, a T die or the like is preferably used.
• two or more pressure dies may be provided on the metal support, and the dope amount may be divided and stacked.
• the drying step on the metal support is a step in which the web (the name of the dope film after casting on the metal support is referred to as the web) is heated on the support to evaporate the solvent.
• the web the name of the dope film after casting on the metal support is referred to as the web
• the solvent In order to evaporate the solvent, there are a method in which heated air is blown from the web side and the back side of the support, a method in which heat is transferred from the back side of the support by a heated liquid, and a method in which heat is transferred from the front and back by radiant heat. A method of combining them is also preferable. Also, if the web is thin, it dries quickly.
• the temperature of the metal support may be the same or different depending on the position.
• the drying method on the metal support suitable for the present invention is, for example, preferably cast at a metal support temperature of 0 to 40 ° C, preferably 5 to 30 ° C.
• the drying wind applied to the web is preferably about 30 to 45 ° C, but is not limited thereto.
• the peeling step is a step in which the organic solvent is evaporated on the metal support and the web is peeled before the metal support goes around, and then the web is sent to the drying step.
• the position at which the web is peeled from the metal support is called the peeling point, and the roll that assists the peeling is called the peeling roll.
• the amount of the residual solvent to be peeled is preferably 20 to 40% by mass or 60 to 150% by mass, particularly preferably 80 to 140% by mass.
• Gel casting method (gel casting) that can peel even when there is a large amount of residual solvent, as a method to increase the film forming speed (the amount of residual solvent is as high as possible, and the film forming speed can be increased because it peels in time) There is.
• the method there are a method in which a poor solvent for the cellulose ester is removed in the dope and the gel is formed after casting the dope, and a method in which the temperature of the support is lowered to form a gel.
• the amount of residual solvent used in the present invention can be expressed by the following formula.
• Residual solvent amount (mass%) ⁇ (M-N) / N ⁇ X 100
• M is the mass of the web at any point
• N is the mass when M is dried at 110 ° C for 3 hours.
• the film peeled off from the support is further dried so that the residual solvent amount is 2.0% by mass or less, more preferably 1.0% by mass. More preferably, it is 0.5% by mass or less.
• the roll is dried while the web is transported by a roll drier in which the rolls are arranged in a staggered manner, a tenter drier that holds the width of the web with a clip, and holds the width or stretches slightly in the width direction.
• the method is adopted.
• it is particularly preferable in order to improve the humidity stability of the optical performance by holding or stretching in an arbitrary process after peeling from the support of the tenter drying apparatus and in an arbitrary residual solvent amount. Good.
• the means for drying the web is not particularly limited, and is generally carried out with hot air, infrared rays, a heating roll, microwaves, or the like. It is preferable to use hot air for simplicity.
• drying temperature stepwise in the range of 40 to 180 ° C. 50 to more preferably in the range of 160 ° C.
• the cellulose ester film of the present invention is preferably stretched by 1% or more in both MD (film transport direction) and TD (perpendicular to the transport direction) in order to ensure flatness. It is preferable that the MD stretch ratio and the TD stretch ratio are close when the film does not have a phase difference in the plane, but the stretch ratio in the MD and TD directions may be different. . However, the sum of the MD stretching ratio and the TD stretching ratio is adjusted as appropriate because the smaller one has a lower cadence value Rt. Further, from the viewpoint of the effect of reducing Rt, it is preferable to carry out at a high temperature during any stretching.
• the stretching operation may be performed in multiple stages, and it is preferable to perform biaxial stretching in the casting direction and the width direction.
• biaxial stretching when biaxial stretching is performed, simultaneous biaxial stretching may be performed or may be performed stepwise.
• stepwise means that, for example, stretching in different stretching directions can be sequentially performed, stretching in the same direction is divided into multiple stages, and stretching in different directions is performed in any one of the stages. It is also possible to add.
• a thinner cellulose ester film is preferable because the resulting polarizing plate becomes thinner and the liquid crystal display can be easily thinned. However, if it is too thin, moisture permeability, tear strength, etc. deteriorate. .
• the film thickness of the cellulose ester film that achieves both of these is preferably 10 to: lOO x m force S, more preferably 10 to 80 111, more preferably 10 to 60 ⁇ m force S, and particularly preferably 20 to 45 x m.
• the width of the cellulose ester film is preferably 1.4 m or more, and more preferably in the range of 1.4 m to 4 m for a large-sized liquid crystal display device from the viewpoint of productivity.
• the cellulose ester film of the present invention is suitable for polarizing plates used in various liquid crystal display devices, and the cellulose ester film on the brightness enhancement film side is an in-plane retardation Ro (550) represented by the following formula (I).
• Ro 550
• the retardation Rt (550) in the thickness direction represented by the following formula (II) is in the range of 15 to 15 nm.
• Nx and Ny are the maximum and minimum values of the refractive index in the film plane, Nz is the refractive index in the thickness direction, d is the film thickness, and Ro (550) and Rt (550) are Shows retardation at 550nm wavelength]
• the cellulose ester film on the brightness enhancement film side is in the range of 0 to 5 nm for Ro (400) and Ro (700), and Rt (400) and Rt (700) are each 15 Les, preferably in the range of ⁇ 15nm.
• the return value Ro (400), Ro (550), Ro (700), Rt (400), Rt (550), R t (700) can be measured by changing the wavelength using an automatic birefringence meter. For example, using K ⁇ BRA-21ADH (Oji Scientific Instruments), 23 ° C, 55. Can be obtained in an environment of / 0 RH.
• the cellulose ester film of the present invention is preferably provided with a hard coat layer containing the following actinic ray curable resin.
• the actinic radiation curable resin layer refers to a layer mainly composed of a resin that is cured through a crosslinking reaction or the like by irradiation with actinic rays such as ultraviolet rays or electron beams.
• actinic radiation curable resin a component containing a monomer having an ethylenically unsaturated double bond is preferably used, and a hard coat layer is formed by curing by irradiation with actinic radiation such as ultraviolet rays or electron beams.
• Typical examples of the actinic radiation curable resin include an ultraviolet curable resin and an electron beam curable resin, and a resin curable by ultraviolet irradiation is preferable.
• Examples of the ultraviolet curable resin include an ultraviolet curable urethane acrylate resin, an ultraviolet curable polyester acrylate resin, an ultraviolet curable epoxy acrylate resin, an ultraviolet curable polyol acrylate resin, Alternatively, an ultraviolet curable epoxy resin or the like is preferably used.
• UV curable acrylic urethane resins are generally obtained by reacting a polyester polyol with an isocyanate monomer or a prepolymer, and further adding 2-hydroxysethyl acrylate or 2-hydroxyethyl methacrylate.
• a polyester polyol with an isocyanate monomer or a prepolymer, and further adding 2-hydroxysethyl acrylate or 2-hydroxyethyl methacrylate.
• 2-hydroxysethyl acrylate or 2-hydroxyethyl methacrylate are included in the acrylate as including methacrylate
• an acrylate monomer having a hydroxyl group such as 2-hydroxypropyl acrylate.
• those described in JP-A-59-151110 can be used.
• UV curable polyester acrylate resins generally include those that are easily formed by reacting polyester polyols with 2-hydroxyethinoaretalate or 2-hydroxy acrylate monomers. And those described in JP-A-59-151112 can be used.
• an epoxy acrylate polymer is used as an oligomer, and a reactive diluent and a photoinitiator are added to the oligomer and reacted to form an oligomer.
• a reactive diluent and a photoinitiator are added to the oligomer and reacted to form an oligomer.
• UV curable polyol acrylate resin examples include trimethylol propantriate, ditrimethylolpropane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexatalylate, Examples include alkyl-modified dipentaerythritol pentaatarylate.
• photoinitiators of these ultraviolet curable resins include benzoin and derivatives thereof, acetophenone, benzophenone, hydroxybenzophenone, Michler's keton, ⁇ -amiguchi oxime ester, thixanthone, and the like. Derivatives can be mentioned. You may use with a photosensitizer.
• the above photoinitiator can also be used as a photosensitizer.
• sensitizers such as ⁇ _ptylamine, triethylamine, and tri- ⁇ _butylphosphine can be used.
• the photoreaction initiator or photosensitizer used in the ultraviolet ray curable resin composition is 0.1 to 15 parts by mass, preferably 1 to 10 parts by mass with respect to 100 parts by mass of the composition. is there.
• Examples of the resin monomer include a monomer having an unsaturated double bond as a single monomer such as methyl phthalate, ethinorea tallylate, butinorea talelate, benzenorea tallylate, cyclohexyl acrylate, butyl acetate, Examples include general monomers such as styrene.
• monomers having two or more unsaturated double bonds include ethylene glycol ditalylate, propylene glycol ditalylate, dibutenebenzene, 1,4-cyclohexanediatalylate, 1,4-cyclohexyldimethyl.
• Examples include Asian tallate, the above-mentioned trimethylol bromide pantoria tallate, pentaerythritol tetraacrylic ester, etc. come.
• compounds include trimethylolpropane tritalylate, ditrimethylomonorepropanetetratalylate, pentaerythritol retriatalylate, pentaerythritol tetraatalylate, dipentaerythritol hexaatalyl. Rate, alkyl-modified dipentaerythritol pentaatalylate and the like.
• actinic radiation curable resin layers can be coated by a known method such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, or an ink jet method.
• any light source that generates ultraviolet rays can be used without any limitation.
• a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used.
• Irradiation conditions vary with each lamp.
• the irradiation dose of the actinic radiation is preferably 5 to: 150 mj / cm 2 , particularly preferably 20 to 100 mj / cm 2 .
• tension in the film transport direction when irradiating actinic radiation, it is preferable to apply tension in the film transport direction, and more preferably to apply tension in the width direction.
• the applied tension is preferably 30 to 300 N / m.
• the method of applying tension is not particularly limited, and tension may be applied in the width direction or biaxial direction by a tenter that may apply tension in the transport direction on the back roll. This makes it possible to obtain a film having further excellent flatness.
• Examples of the organic solvent for the UV curable resin layer composition coating solution include hydrocarbons (toluene, xylene), alcohols (methanol, ethanol, isopropanol, butanol, cyclohexanol), and ketones. (Acetone, methyl ethyl ketone, methyl isobutyl ketone), esters (methyl acetate, ethyl acetate, methyl lactate), glycol ethers, and other organic solvents can be appropriately selected or used by mixing them.
• Propylene glycol monoalkyl ether (1 to 4 carbon atoms in the alkyl group) or propylene glycol monoalkyl ether acetate ester (1 to 4 carbon atoms in the alkyl group) is 5 % by mass or more, more preferably. It is preferable to use the above organic solvent containing 5 to 80% by mass or more.
• a silicon compound to the ultraviolet curable resin layer composition coating solution.
• polyether-modified silicone oil is preferably added.
• the number average molecular weight of the polyether-modified silicone oil is, for example, 1,000,000 to 100,000, preferably 2,000 to 50,000, and if the number average molecular weight is less than 1,000, the coating is dried. On the other hand, if the number average molecular weight exceeds 100,000, it is difficult to pre-load on the surface of the coating.
• silicon compounds include DKQ8 _ 779 (trade name, manufactured by Dow Coung), SF 3771, SF8410, SF8411, SF8419, SF8421, SF8428, SH200, SH510, SH1107, SH3749, SH3771, BX16-034, SH3746, SH3749, SH8400, S H3771M, SH3772M, SH3773M, SH3775M, BY— 16— 837, BY— 16— 8 39, BY— 16— 869, BY— 16— 870, BY— 16— 004, BY— 16— 891, BY— 16 — 872, BY— 16— 874, BY22— 008M, BY22— 012M, FS— 1265 (above, product name manufactured by Toray Dow Cowing Silicone), KF—101, KF—100T, KF351, KF3 52, KF353 , KF354, KF355, KF61
• BYK— 307 BYK— 341, BYK— 344, BYK— 361 (Bick Chemi-Janon) L series (eg L7001, L-7006, L—7604, L — 9000) manufactured by Nippon Tunica ), Y series, FZ series (FZ-2203, FZ-2206, FZ-2207) and the like, and preferably used.
• These components enhance the coating property of the base material to the lower layer. When added to the outermost surface layer of the laminate, it also has an effect on the scratch resistance of the surface with force if it increases the water repellency, oil repellency and antifouling property of the coating film. These components are preferably added in the range of 0.01 to 3% by mass, based on the solid components in the coating solution.
• the coating amount is suitably 0.5 :! to 30 ⁇ m, preferably 0.5 to 15 m, as the wet film thickness.
• the dry film thickness is 0.1 to 20 ⁇ , preferably 1 to 10 zm.
• the ultraviolet curable resin composition is preferably irradiated with ultraviolet rays during or after coating and drying.
• the irradiation time for obtaining the irradiation dose of the active ray of 5 to 150 mjZcm 2 is from 0.1 second to From 10 to 10 seconds is more preferable from the viewpoint of curing efficiency or work efficiency of the ultraviolet curable resin, which takes about 5 minutes.
• the illuminance of the active ray irradiation unit 50 is preferably 150 mW / m 2.
• the cured resin layer obtained in this way is fine particles of an inorganic compound or an organic compound. Can also be added.
• the inorganic fine particles used in the hard coat layer include silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, magnesium oxide, calcium carbonate, Tanorek, clay, Examples include calcined kaolin, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate.
• silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, magnesium oxide and the like are preferably used.
• the organic fine particles include polymethyl methacrylate methyl acrylate resin powder, styrene resin powder, polymethyl methacrylate resin powder, silicon resin powder, polystyrene resin powder, polycarbonate resin powder, benzoguanamine. Resin powder, melamine resin powder, polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, polyfluorinated styrene resin powder, or other ultraviolet curable resin composition.
• cross-linked polystyrene particles for example, SX-130H, SX-200H, SX-350H, manufactured by Soken Chemical Co., Ltd.
• polymethylol methacrylate-based particles for example, MX150, MX300 manufactured by Soken Chemical.
• the average particle size of these fine particle powders is preferably 0.005 to 5 ⁇ m, and particularly preferably 0.01 to 1 ⁇ m. It is desirable that the ratio of the ultraviolet curable resin composition and the fine particle powder is 0.:! To 30 parts by mass with respect to 100 parts by mass of the resin composition.
• the UV curable resin layer is a clear hard coat layer with a centerline average roughness (Ra) specified in JIS B 0601 of 1 to 50 nm, or Ra is about 0.:! To about 1 ⁇ m It is preferable that the light diffusing layer be a power S.
• the center line average roughness (Ra) is preferably measured with an optical interference type surface roughness measuring instrument, for example, RSTZPLUS manufactured by WYKO.
• the pencil height of the ultraviolet curable resin layer is preferably H-8H, preferably 2H-4H.
• the hardness of the pencil pulling test (pencil hardness) is for testing specified by JIS-S-6006 after conditioning the prepared hard coat film sample for 2 hours at a temperature of 25 ° C and a relative humidity of 60%.
• a polarization conversion element having a function of separating light emitted from a light source (backlight) into transmitted polarized light, reflected polarized light, or scattered polarized light is used.
• Such brightness enhancement films utilize retroreflected light from reflected or scattered polarized backlights. Thus, the output efficiency of linearly polarized light can be improved.
• An example of the brightness enhancement film is an anisotropic reflective polarizer.
• An anisotropic reflective polarizer includes an anisotropic multiple thin film that transmits linearly polarized light in one vibration direction and reflects linearly polarized light in the other vibration direction.
• An example of the anisotropic multi-thin film is DBM manufactured by 3M (see, for example, JP-A-4-268505).
• An example of the anisotropic reflective polarizer is a composite of a cholesteric liquid crystal layer and a ⁇ / 4 plate.
• An example of a powerful composite is PCF manufactured by Nitto Denko (refer to Japanese Laid-Open Patent Publication No. 11-231130).
• An example of the anisotropic reflective polarizer is a reflective grid polarizer.
• Reflective grid polarizers include metal grid reflective polarizers (see US Pat. No. 6,288,840) that perform reflective processing in the visible light region by applying microfabrication to metals, and polymer matrix. Examples thereof include those stretched in the inside (see JP-A-8-184701, etc.).
• An example of the brightness enhancement film is an anisotropic scattering polarizer.
• An example of the anisotropic scattering polarizer is DRPF manufactured by 3 mm (see US Pat. No. 5,825,543).
• examples of the brightness enhancement film include a polarizing element capable of performing polarization conversion in one pass.
• a polarizing element capable of performing polarization conversion in one pass.
• smectic C * are mentioned (see JP-A-2001-201635).
• An anisotropic diffraction grating can be used as the brightness enhancement film.
• the adhesive for bonding the polarizing plate and the brightness enhancement film is not particularly limited.
• Those having a polymer as a base polymer can be appropriately selected and used.
• those which are excellent in optical transparency, exhibit appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties, and are excellent in weather resistance, heat resistance and the like are preferably used.
• the adhesive may contain a crosslinking agent according to the base polymer.
• the adhesive include natural and synthetic resins, in particular, tackifier resins, glass fibers, glass beads, metal powders, other inorganic powders, fillers, pigments, colorants, oxidation agents, and the like.
• An additive such as an inhibitor may be contained. Further, it may be an adhesive layer containing fine particles and exhibiting light diffusibility.
• the adhesive is usually used as an adhesive solution having a solid content concentration of about 10 to 50% by mass in which a base polymer or a composition thereof is dissolved or dispersed in a solvent.
• a solvent an organic solvent such as toluene or ethyl acetate or a solvent suitable for the type of adhesive such as water can be appropriately selected and used.
• the polarizing plate (A) of the present invention can be produced by a general method.
• the cellulose ester film of the present invention is obtained by subjecting at least one surface to an alkali hatching treatment, and using a completely hatched polyvinyl alcohol aqueous solution on both sides of a polarizer prepared by immersing and stretching the treated film in an iodine solution. It is preferable to stick them together.
• a polarizer which is a main component of a polarizing plate, is an element that allows only light of a plane of polarization in a certain direction to pass through.
• a typical polarizer currently known is a polybulu alcohol-based polarizing film.
• a polybulal alcohol aqueous solution is formed into a film and dyed by uniaxial stretching or dyed or uniaxially stretched and then preferably subjected to a durability treatment with a boron compound. .
• the film thickness of the polarizer is 5 to 40 x m, preferably 5 to 30 x m, and particularly preferably 5 to 25 z m.
• a polarizing plate is formed by laminating the cellulose ester film of the present invention on the surface of the polarizer. Preferably, it is bonded completely with a water-based adhesive mainly composed of polybulal alcohol or the like. In the case of a resin film other than a cellulose ester film having a low suitability for kenich, it can be bonded to the polarizing plate through an appropriate adhesive layer.
• the polarizer Since the polarizer is stretched in a uniaxial direction (usually the longitudinal direction), when the polarizing plate is placed in a high-temperature and high-humidity environment, the stretching direction (usually the longitudinal direction) shrinks, and the stretching and vertical direction (usually normal) Extends in the width direction). As the film thickness of the polarizing plate protective film decreases, the expansion / contraction ratio of the polarizing plate increases, and in particular, the amount of contraction in the stretching direction of the polarizer increases.
• the polarizing direction of the polarizer is bonded to the casting direction (MD direction) of the polarizing plate protective film, so When thinning the film, it is particularly important to suppress the expansion / contraction rate in the casting direction. Since the cellulose ester film used in the present invention is excellent in dimensional stability, it is suitably used as such a polarizing plate protective film.
• the polarizing plate can be constituted by further laminating a protective film on one surface of the polarizing plate and a separate film on the other surface.
• the protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection.
• the non-prote film is bonded for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal plate.
• the separate film is used for the purpose of covering the adhesive layer to be bonded to the liquid crystal plate, and is used on the surface side of the polarizing plate to be bonded to the liquid crystal cell.
• the liquid crystal display device of the present invention is a liquid crystal display device in which a brightness enhancement film, a polarizing plate (A), a liquid crystal cell, and a polarizing plate (B) are laminated in this order, and the luminance of the polarizing plate (A)
• the cellulose ester film of the present invention is arranged on the side of the improvement film.
• the cellulose ester film of the present invention may be used on the other surface of each polarizing plate, or another polarizing plate protective film may be used.
• a commercially available cellulose ester film can be used for the polarizing plate protective film used on the other side of the cell mouth sester film of the present invention.
• cellulose ester films include KC 8UX2M, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UCR-3, KC8UCR-4, KC8UCR_5, KC4FR_1 (above, manufactured by Konica Minoltopto Corporation), Fujitac TD80UF Fujitac T80UZ, Fujitac T40UZ, and the like are preferably used.
• KC4FR-1 is preferably used.
• the polarizing plate (B) used on the other surface may have a hard coat layer or an antiglare layer having a thickness of 8 to 20 ⁇ m, particularly in the polarizing plate protective film on the viewing side.
• a polarizing plate protective film having a hard coat layer or an antiglare layer described in JP-A 2003-114333, JP-A 2004-203009, 2004-354699, 2004-354828, etc. is preferably used.
• the above-mentioned antireflection layer including at least a low refractive index layer on the clear hard coat layer or the antiglare layer.
• the low refractive index layer contains hollow fine particles such as silicon dioxide. It is particularly preferred.
• the cellulose ester film of the present invention is a transmissive, transflective LCD or TN type, STN type, OCB type, HAN type, VA type (MV A type, PVA type), IPS type, FFS type, etc. Forces preferably used in LCDs Particularly preferably used in liquid crystal display devices such as VA type (MVA type, PVA type), IPS type and FFS type.
• the polarizing plate of the present invention exhibits excellent brightness improvement when used on the backlight side of a large-screen liquid crystal cell.
• a retardation film between the polarizers of the polarizing plate (A) and the polarizing plate (B) for the purpose of expanding the viewing angle of the liquid crystal display device. It is possible to select an appropriate retardation value for the retardation film according to the characteristics of the liquid crystal cell. Furthermore, a functional film having a phase difference in one or both of the protective films of the polarizing plate (A) and the polarizing plate (B) facing the liquid crystal cell can be preferably used.
• the weight average molecular weight was measured using high performance liquid chromatography.
• the measurement conditions are as follows.
• the refractive index in the slow axis direction in the plane of the sample is nx
• the refractive index in the direction perpendicular to the slow axis in the plane is ny
• the refractive index in the thickness direction of the film is nz
• d is the thickness of the film.
• the above dope solution was prepared with the addition ratio of polymer X and polymer Y shown in Table 1, and then filtered with Finemet NF manufactured by Nippon Seisen Co., Ltd., using a belt casting apparatus, at a temperature of 22 ° C and a width of 2 m, stainless steel. It was cast uniformly on the band support. Residual solvent amount with stainless steel band support The solvent was evaporated until 100% became 100%, and peeling was performed from the stainless steel band support with a peeling tension of 162 N / m. The peeled cellulose ester web was evaporated at 35 ° C, the solvent was slit to 1.6m width, and then dried at a drying temperature of 140 ° C while being stretched 1.1 times in the width direction with a tenter.
• the residual solvent amount when starting stretching with a tenter was 10%.
• relaxation was performed at 130 ° C, and then drying was completed while a dry zone at 120 ° C and 130 ° C was being conveyed by a number of rolls.
• a knurling process having a width of 10 mm and a height of 5 xm was applied to both ends, and a 6-inch inner core with an initial tension of 220 NZm and a final tension of 110 N / m was wound up to obtain cellulose ester films 1 to 6 shown in Table 1.
• the draw ratio in the MD direction calculated from the rotational speed of the stainless steel band support and the running speed of the tenter was 1.1 times.
• the cellulose ester films listed in Table 1 each had a residual solvent amount of 0.1%, a film thickness of 80 / im, and a length of 4000 m. Moreover, the film thickness was changed to 40 / im, and the cellulose ester films 7 to 12 shown in Table 1 were obtained in the same manner as the cellulose ester films 1 to 6.
• Table 2 shows the retardation of the cellulose ester film listed in Table 1.
• HEMA 2—Hydrochetyl methacrylate
• a 120 ⁇ thick polybulu alcohol film was immersed in 100 kg of an aqueous solution containing 1 kg of iodine and 4 kg of boric acid and stretched 6 times at 50 ° C. to prepare a polarizer.
• cell mouth ester film 1 to 12 shown in Table 1 which was subjected to al force saponification treatment under the following conditions, was used as a pressure sensitive adhesive with 5% aqueous solution of complete Ken-type polybulal alcohol. They were pasted together.
• KC8UCR-5 manufactured by Konica Minoltaput Co., Ltd. was used on the other surface of the polarizer, and bonded in the same manner to produce polarizing plates (A):! -12.
• the film sample was saponified, washed with water, neutralized and washed with water under the above conditions, and then dried at 80 ° C.
• a polarizing plate (B) was prepared in the same manner except that KC8UCR-5 and KC8UX2M manufactured by Konica Minoltaput Co., Ltd. were used on both sides of the polarizer as a protective film during the production of the polarizing plate. [0194] ⁇ Brightness enhancement film>
• DBEF anisotropic multiple thin film manufactured by 3M was used.
• a 15-inch liquid crystal display VL-150SD manufactured by Fujitsu was used for the evaluation by peeling off the double-sided polarizing plates.
• a brightness enhancement film, polarizing plates (A) 1 to: 12, liquid crystal cells, and polarizing plates (B) were laminated in this order from the nocrite side, and liquid crystal display devices 1 to 12 were prepared and evaluated.
• the polarizing plate (A) is arranged so that the cellulose ester films 1 to 12 face the brightness enhancing film side of the polarizing plate (A), and the polarizing plate is arranged so that the absorption axis coincides with the direction previously attached to the liquid crystal cell. It was.
• the polarizing plate (B) was arranged so that KC8UCR-5 faces the liquid crystal cell, and the absorption axis of the polarizing plate was reinforced to coincide with the direction of the liquid crystal cell.
• ELDIM EZ-contrast was used to measure the amount of transmitted light during black and white display.
• the results are shown in Table 2.
• the evaluation was performed in a constant temperature and humidity chamber adjusted to 23 ° C 55% in order to keep the heat effect the same.
• the polarizing plate (B) was used instead of the polarizing plate (A) on both sides of the liquid crystal cell, and the viewing angle evaluation data of the liquid crystal display device was used. (refer graph1 )
• the Y direction represents the 0 ° direction in the plane of the liquid crystal display device
• the X direction represents the 90 ° (horizontal direction) direction.
• the distance between a certain point and the origin in the figure represents the inclination of the sensor when the sensor of the measuring instrument is tilted in the direction of the point (the inclination on the normal line is 0 °).
• the curves represent the slope of the sensor with a contrast of 20 in each direction.
• the liquid crystal display device of the present invention shows that the contrast in the oblique direction is increased. Further, as is clear from FIG. 4, it can be seen that the viewing angle in the liquid crystal display device of the present invention is particularly wide in the direction of 45 degrees relative to the comparative product.
• Acrylic monomer KAYARAD DPHA (dipentaerythritol hexaatalylate, manufactured by Nippon Kayaku) 220 parts by mass
• Ilgarcure 184 (Ciba Specialty Chemicals Co., Ltd.) 20 parts by mass 110 parts by mass of propylene glycol monomethyl ether 110 parts by mass of ethynole acetate
• the hard coat layer coating solution is filtered through a polypropylene filter having a pore size of 0.4 ⁇ m to prepare a hard coat layer coating solution, which is then used with a microgravure coater. After drying at 90 ° C and using an ultraviolet lamp, the irradiance is 100 mW / cm 2 and the irradiation dose is 0.1 lj / cm 2 to cure the coating layer. A coat layer was formed to prepare hard coat film 1.
• a liquid crystal display device was produced and evaluated in the same manner as in Example 1 except that the hard coat layer was applied.
• the hard coat layer side was disposed so as to face the backlight.
• Example 3 When evaluation was performed by viewing angle measurement in the same manner as in Example 1, the viewing angle was expanded with respect to the 11 ° standard as in Table 3, and the effect was recognized. In addition, when the viewing angle evaluation condition was changed to 40 degrees 55% and the polarizing plate 2 of Example 1 and the polarizing plate of Example 2 were compared, the viewing angle of Example 1 was 8 °. For the effect, the sample provided with the hard coat layer of Example 2 showed a good result stable to temperature fluctuations, such as 11 °.
• Example 3
• the liquid crystal display device using the polarizing plates 2 and 8 described in Example 1 was used, and the luminance at the time of white display in an oblique 45 ° direction was relatively compared.
• a spectral radiance meter CS-1000A manufactured by Konica Minolta was used as for the orientation characteristic of luminance. Place the sensor of the spectral radiance meter on the normal of a certain point in the plane of the liquid crystal display, and gradually tilt it in the direction of 45 ° while maintaining a certain distance while pointing the sensor at the same point, 0 ° ⁇ 90 ° The luminance was measured in the range of. However, the inclination when the sensor is on the normal was set to 0 °. At this time, the angle at which half the luminance at the front (0 °) was obtained was evaluated.
• the luminance half-value angle of the 40 ⁇ film of the present invention was expanded by 8 ° with respect to Sample 2 of the 80 a film of the present invention.
• the clear principle of this is not clear, but the light scattering is less in the 40 ⁇ film than in the 80 ⁇ film because of the small scattering inside the film. It is thought that the brightness in the long diagonal direction increased.
• the present invention it is possible to provide a liquid crystal display device which prevents a decrease in light utilization efficiency in the oblique direction in the liquid crystal display device, and in particular, increases the luminance in the oblique direction and expands the viewing angle.

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• 2006
  • 2006-08-24 WO PCT/JP2006/316573 patent/WO2007026593A1/ja active Application Filing
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