WO2013005716A1 - Film protecteur pour lame de polariseur, son procédé de fabrication, lame de polariseur et dispositif d'affichage à cristaux liquides - Google Patents

Film protecteur pour lame de polariseur, son procédé de fabrication, lame de polariseur et dispositif d'affichage à cristaux liquides Download PDF

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WO2013005716A1
WO2013005716A1 PCT/JP2012/066891 JP2012066891W WO2013005716A1 WO 2013005716 A1 WO2013005716 A1 WO 2013005716A1 JP 2012066891 W JP2012066891 W JP 2012066891W WO 2013005716 A1 WO2013005716 A1 WO 2013005716A1
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polarizing plate
cellulose ester
ester resin
film
protective film
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PCT/JP2012/066891
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English (en)
Japanese (ja)
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翠 木暮
啓史 別宮
田坂　公志
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コニカミノルタアドバンストレイヤー株式会社
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Priority to JP2013523012A priority Critical patent/JP6086064B2/ja
Publication of WO2013005716A1 publication Critical patent/WO2013005716A1/fr

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    • 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
    • C08L1/14—Mixed esters, e.g. cellulose acetate-butyrate
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/10—Optical coatings produced by application to, or surface treatment of, optical elements
    • G02B1/14—Protective coatings, e.g. hard coatings
    • G02B1/105—

Definitions

  • the present invention relates to a protective film for a polarizing plate, a production method thereof, a polarizing plate, and a liquid crystal display device.
  • a liquid crystal display is generally composed of a backlight unit, a liquid crystal cell, and a polarizing plate.
  • a polarizing plate usually comprises a protective film for a polarizing plate and a polarizer (also referred to as “polarizing film”).
  • polarizer also referred to as “polarizing film”.
  • a polarizer a polyvinyl alcohol film dyed with iodine and stretched is often used, and both surfaces thereof are covered with a protective film for a polarizing plate.
  • a protective film for a polarizing plate a cellulose triacetate (TAC) film having excellent moisture permeability and excellent adhesion to a polarizer is often used.
  • TAC cellulose triacetate
  • the liquid crystal display device is not a self-luminous display device
  • a light source such as a cold cathode tube (CCFL) or LED is provided on the back side of the liquid crystal cell (backlight type) or on the edge portion (edge light type) of the light guide plate. Is always placed.
  • these light sources are generally line light sources or point light sources
  • a diffusion sheet or a diffusion film is used in order to form a uniform surface light source.
  • the diffusion sheet has interference fringes such as moiré caused by interference between a prism sheet often used as a member for imparting directivity to light and incident light, or interference between pixels in a liquid crystal cell and incident light. Can be suppressed.
  • Patent Document 1 proposes a light diffusing polarizing plate having a light diffusing layer having predetermined characteristics, which contains porous amorphous particles and spherical particles in a dispersed manner, and discloses that a light diffusing sheet can be omitted by this. ing. According to this method, it is possible to eliminate moiré fringes, but when forming a polarizing plate, there is a problem that fine particles fall off and cause process contamination, and the front luminance decreases when a display device is used. There was a problem.
  • Patent Documents 2 and 3 it is proposed to use a light diffusion film containing translucent fine particles and crosslinkable fine particles as a protective film for a polarizing plate.
  • a light diffusion film containing translucent fine particles and crosslinkable fine particles as a protective film for a polarizing plate.
  • problems such as the dropout of fine particles when forming a polarizing plate as described above, and the problem that it cannot be produced at low cost.
  • Patent Documents 4 and 5 a light scattering film having a sea-island structure in which a dope composed of a plurality of resins is cast on a support and phase-separated, or a mixed solution of a plurality of resins is applied onto the support film.
  • a light scattering film produced in this manner is disclosed. According to this method, it is possible to produce a film having light diffusibility, and since fine particles are not used, it is possible to solve the problem of fine particle falling off.
  • a polarizing plate was produced by using it, it was found that there was a problem that the adhesion between the film and the polarizer was poor and it was difficult to form a polarizing plate.
  • the present invention has been made in view of the above-mentioned problems and situations, and the problem to be solved is as a protective film for a polarizing plate having a concavo-convex shape on the surface, adhesion with a polarizer, and dimensions under high temperature and high humidity.
  • An object of the present invention is to provide a polarizing plate protective film having an excellent light diffusion function, which is excellent in stability and can sufficiently eliminate moire fringes when used as a protective film for a backlight side polarizing plate in a liquid crystal display device. .
  • Another object of the present invention is to provide a method for producing a protective film for a polarizing plate having a light diffusing function that can be produced by an easy process, without causing process contamination due to fine particle dropping, and further, a polarizing plate provided with the protective film for a polarizing plate. And providing a liquid crystal display device.
  • the present inventors pay attention to a cellulose ester film that is generally used as a protective film for a conventional polarizing plate, and by combining cellulose ester resins having different chemical structures, it is sufficient for eliminating moire.
  • a protective film for polarizing plates having a light diffusing function could be provided and studied.
  • cellulose ester resins are compatible with each other and cannot have a light diffusion function.
  • the present inventors have found that when a resin to be combined satisfies a specific relationship, a protective film for a polarizing plate having a light diffusion function composed of cellulose ester resins can be provided, and the present invention has been achieved. .
  • a protective film for a polarizing plate comprising a cellulose ester resin A and a cellulose ester resin B and having a concavo-convex surface and satisfying the following requirements (A) to (C):
  • (Z) defined by the following formula 1 regarding the propionyl group substitution degree (PrA) of the resin A, and defined by the following formula 2 regarding the acetyl group substitution degree (AcB) and the propionyl group substitution degree (PrB) of the resin B
  • (Y) is within the range of PrA ⁇ 0.5, and Y ⁇ Z.
  • PrA degree of propionyl group substitution
  • AcB degree of propionyl group substitution
  • PrB degree of propionyl group substitution
  • a polarizing plate comprising the polarizing plate protective film having the uneven shape according to any one of items 1 to 3 on at least one surface of a polarizer.
  • a liquid crystal display device comprising the polarizing plate according to item 5 on at least one surface of a liquid crystal cell.
  • a polarizing plate protective film having a concavo-convex shape on the surface it has excellent adhesion to a polarizer and dimensional stability under high temperature and high humidity, and is used for a backlight side polarizing plate of a liquid crystal display device.
  • a protective film for a polarizing plate that can sufficiently eliminate moire fringes and has an excellent light diffusion function.
  • a method for producing a protective film for a polarizing plate having a light diffusing function that can be produced by an easy process without process contamination due to dropping off of the fine particles, and further a polarizing plate provided with the protective film for a polarizing plate.
  • a liquid crystal display device can be provided.
  • the protective film for polarizing plate of the present invention comprises a sea-island structure composed of a continuous phase composed of cellulose ester resin A corresponding to the sea and a dispersed phase composed of cellulose ester resin B corresponding to the islands. It is necessary to form an uneven shape.
  • cellulose ester resins are compatible with each other, and an uneven shape having a sea-island structure is not formed, so that a light diffusion function cannot be provided.
  • the present inventor has selected the acyl groups and substituted acyl groups of the resin A used as the main component and the resin B used as the subcomponent as a combination of the cellulose ester resin A and the cellulose ester resin B to be blended. Focusing on the degree, the present inventors have found that an irregular shape with a sea-island structure can be formed only when both of the acyl substituent and the degree of acyl group substitution satisfy the requirements (A) to (C) of the present invention.
  • a soft resin is preferable, and a cellulose ester resin having a flexible substituent and cellulose acetate propionate are suitable.
  • PrA propionyl substitution degree
  • a cellulose ester resin that is easily intermolecularly or intermolecularly suitable is suitable.
  • the cellulose ester resin B may be any cellulose ester resin regardless of the type of acyl group, such as cellulose diacetate, cellulose triacetate, cellulose acetate propionate, and cellulose acetate butyrate, but the above requirements (A) to (C ) And a cellulose ester resin having an acyl group satisfying (C) and an acyl group substitution degree.
  • a sea-island structure sufficient for the light diffusion function can be formed by using resin A as a flexible cellulose ester resin and resin B as a cellulose ester resin having some rigidity.
  • the protective film for a polarizing plate of the present invention is a protective film for a polarizing plate having a concavo-convex shape on the surface containing the cellulose ester resin A and the cellulose ester resin B, and satisfies the relations of the requirements (A) to (C).
  • the protective film for polarizing plates which has the light-diffusion function which solves the said subject which concerns on this invention by satisfy
  • the propionyl group substitution degree (PrA) of the cellulose ester resin A is preferably in the range of 0.5 to 1.2.
  • the arithmetic average roughness Ra of at least one surface of the protective film for plates is preferably in the range of 0.1 to 0.4 ⁇ m.
  • the method for producing a protective film for polarizing plate for producing the protective film for polarizing plate of the present invention preferably includes at least the steps (1) to (4).
  • the protective film for polarizing plates of the present invention is suitably provided for polarizing plates and liquid crystal display devices.
  • ⁇ is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.
  • the protective film for a polarizing plate of the present invention is a protective film for a polarizing plate containing cellulose ester resin A and cellulose ester resin B and having a concavo-convex surface, and satisfies the following requirements (A) to (C): It is characterized by.
  • (A) Cellulose ester resin A is cellulose acetate propionate
  • the protective film for a polarizing plate of the present invention is a protective film for a polarizing plate having an uneven shape with a sea-island structure composed of a continuous phase corresponding to the sea and a dispersed phase corresponding to an island.
  • the main component of the resin that constitutes the island is a cellulose ester resin, and the resin that constitutes the sea is also a cellulose ester resin having different acyl group substituents and different degrees of substitution.
  • a protective film for a polarizing plate having excellent light diffusibility is obtained.
  • the arithmetic average roughness Ra of the surface of at least one polarizing plate protective film is in the range of 0.1 to 0.4 ⁇ m from the effect of eliminating moire fringes. That is, this invention relates to the protective film for polarizing plates comprised from several resin (it is also called a "polymer”) containing a cellulose ester, and has the uneven
  • a protective film for a polarizing plate having an irregular shape with a sea-island structure in which the arithmetic average roughness Ra based on JIS B0601-2001 is adjusted within the range of 0.1 to 0.4 ⁇ m can be produced.
  • the value of Ra is 0.1 ⁇ m or more, a sufficient scattering effect can be obtained and moire fringes can be eliminated.
  • Ra is 0.4 ⁇ m or less, it is preferable that the front luminance does not decrease when a display device
  • the protective film for a polarizing plate of the present invention is used as a protective film for a polarizing plate on the backlight side of a liquid crystal display device, a liquid crystal display device with excellent image quality in which moire fringes are eliminated can be provided.
  • Arithmetic average roughness Ra is measured by a measuring instrument according to JIS B0601-2001, such as Olympus 3D Laser Microscope LEXT OLS4000, Kosaka Laboratory Co., Ltd., Surfcoder MODEL SE-3500, etc.
  • the shape of the island can be observed with the laser microscope.
  • FIG. 1 shows a surface observation photograph by a 3D laser microscope of a protective film for a polarizing plate having an uneven shape according to the present invention.
  • the cellulose ester resin according to the present invention includes (A) the cellulose ester resin A as cellulose acetate propionate, (C) (Z) defined by the above formula 1 relating to the propionyl group substitution degree (PrA) of the resin A, and the resin.
  • the relationship of (Y) defined in Formula 2 with respect to the acetyl group substitution degree (AcB) and propionyl group substitution degree (PrB) of B satisfies Y ⁇ Z within the range of PrA ⁇ 0.5.
  • the cellulose ester resin A is cellulose acetate propionate
  • the preferred lower fatty acid ester of cellulose acetate propionate has an acyl group having 2 to 4 carbon atoms as a substituent, and the substitution degree of acetyl group is X.
  • the substitution degree of the propionyl group is P, it is preferably a cellulose ester resin satisfying the following formula (I).
  • the cellulose ester resin A preferably has a propionyl group substitution degree PrA of 0.5 or more.
  • PrA propionyl group substitution degree
  • the sea-island structure is not formed, and it is necessary that PrA ⁇ 0.5.
  • PrA is in the range of 0.5 to 1.2, it is easy to obtain adhesion when saponified with an alkaline aqueous solution as a protective film for a polarizing plate and bonded to a polarizer with water paste. More preferable.
  • the cellulose ester resin B only needs to contain either an acetyl group or a propionyl group as an acyl group, and may contain a butyryl group, a pentanate group, a hexanate group, or the like as another acyl group.
  • preferably used cellulose ester resin B is a mixed fatty acid ester such as cellulose acetate, cellulose diacetate, cellulose triacetate, cellulose propionate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate pentanate, etc. But you can.
  • the method for measuring the degree of acyl group substitution can be measured according to ASTM-D817-96.
  • the degree of acyl group substitution represents the total ratio of cellulose esterified at the 2nd, 3rd and 6th positions of the repeating unit. Specifically, the substitution degree is 1 when the hydroxy groups (hydroxyl groups) at the 2-position, 3-position and 6-position of cellulose are esterified 100%. Therefore, when all of the 2nd, 3rd and 6th positions of the cellulose are 100% esterified, the degree of substitution is 3 at the maximum.
  • the protective film for polarizing plate of the present invention is preferably stretched at a temperature at which the stretching temperature T satisfies Tg (A) ⁇ T ⁇ Tg (B) in the stretching step
  • the resin B is preferably selected such that Tg (A) ⁇ Tg (B).
  • the Tg (A) and Tg (B) represent the glass transition temperatures of the cellulose ester resin A and the cellulose ester resin B, respectively.
  • the Tg of the cellulose ester resin can be measured by a differential scanning calorimetry method. Specifically, this is performed using a DSC-7 differential scanning calorimeter (Perkin Elmer) and a TAC7 / DX thermal analyzer controller (Perkin Elmer).
  • resin 4.5-5.0 mg is precisely weighed to 0.01 mg, sealed in an aluminum pan, and set in a DSC-7 sample holder.
  • the reference used an empty aluminum pan.
  • the measurement conditions are as follows: measurement temperature 0 to 200 ° C, temperature increase rate 10 ° C / min, temperature decrease rate 10 ° C / min, with Heat-Cool-Heat temperature control, and analysis based on the 2nd Heat data Do.
  • Tg draws an extension of the baseline before the rise of the first endothermic peak and a tangent line indicating the maximum slope between the rising end of the first endothermic peak and the peak apex, and the intersection is defined as Tg.
  • the raw material cellulose of the cellulose ester used in the present invention may be wood pulp or cotton linter, and the wood pulp may be softwood or hardwood, but softwood is more preferable.
  • a cotton linter is preferably used from the viewpoint of peelability during film formation.
  • the cellulose ester made from these can be mixed suitably or can be used independently.
  • the ratio of cellulose ester derived from cellulose linter: cellulose ester derived from wood pulp (coniferous): cellulose ester derived from wood pulp (hardwood) is 100: 0: 0, 90: 10: 0, 85: 15: 0, 50:50: 0, 20: 80: 0, 10: 90: 0, 0: 100: 0, 0: 0: 100, 80:10:10, 85: 0: 15, 40:30:30.
  • the cellulose ester resin according to the present invention can be synthesized with reference to the methods described in JP-A Nos. 10-45804 and 2005-281645.
  • the cellulose ester resin according to the present invention is preferably 1 ppm or less for the iron (Fe) component as a trace metal component in the cellulose ester.
  • the calcium (Ca) component is 60 ppm or less, preferably 0 to 30 ppm.
  • the magnesium (Mg) component is preferably 0 to 70 ppm, particularly preferably 0 to 20 ppm.
  • Metal components such as iron (Fe) content, calcium (Ca) content, magnesium (Mg) content, etc., are pre-treated by microdigest wet cracking equipment (sulfuric acid decomposition) and alkali melting After being performed, it can be analyzed using ICP-AES (Inductively Coupled Plasma Atomic Emission Spectrometer).
  • the ratio of the cellulose ester resin A is less than 60, it is not preferable because a sea-island structure cannot be formed or a uniform film cannot be produced.
  • the ratio of the cellulose ester resin A is larger than 95, it is not preferable because a sea-island structure is hardly formed and sufficient light diffusibility and moire eliminating ability cannot be obtained.
  • plasticizer In the protective film for polarizing plates of this invention, it is also possible to use a plasticizer together in order to improve the fluidity and flexibility of the composition.
  • plasticizer include phthalate ester, fatty acid ester, trimellitic ester, phosphate ester, polyester, and epoxy.
  • polyester-based and phthalate-based plasticizers are preferably used.
  • Polyester plasticizers are superior in non-migration and extraction resistance compared to phthalate ester plasticizers such as dioctyl phthalate, but phthalate ester plasticizers are excellent in plasticizing effect and compatibility.
  • the polyester plasticizer is a reaction product of a monovalent or tetravalent carboxylic acid and a monovalent or hexavalent alcohol, and is mainly obtained by reacting a divalent carboxylic acid with a glycol.
  • Representative divalent carboxylic acids include glutaric acid, itaconic acid, adipic acid, phthalic acid, azelaic acid, sebacic acid and the like.
  • glycol examples include glycols such as ethylene, propylene, 1,3-butylene, 1,4-butylene, 1,6-hexamethylene, neopentylene, diethylene, triethylene, and dipropylene. These divalent carboxylic acids and glycols may be used alone or in combination.
  • the ester plasticizer may be any of ester, oligoester, and polyester types, and the molecular weight is preferably in the range of 100 to 10,000, and preferably in the range of 600 to 3000, which has a large plasticizing effect.
  • the viscosity of the plasticizer has a correlation with the molecular structure and molecular weight, but in the case of an adipic acid plasticizer, the range of 200 to 5000 MPa ⁇ s (25 ° C.) is preferable because of compatibility and plasticization efficiency. Further, some polyester plasticizers may be used in combination.
  • the plasticizer is preferably added in an amount of 0.5 to 30 parts by mass with respect to 100 parts by mass of the film of the present invention. If the added amount of the plasticizer exceeds 30 parts by mass, the surface becomes sticky, which is not preferable for practical use.
  • the protective film for polarizing plate of the present invention has at least one furanose structure or pyranose structure, and is a compound obtained by esterifying all or part of OH groups in a compound having 1 to 12 furanose structures or pyranose structures bonded thereto (In this application, it may be called a sugar ester compound.).
  • Examples of preferable “compounds having at least one furanose structure or pyranose structure and having 1 to 12 furanose structures or pyranose structures bonded to each other” include JP-A Nos. 62-42996 and 10-237084. It is described in. Monopet SB (Daiichi Kogyo Seiyaku Co., Ltd.) is mentioned as a commercial item.
  • the protective film for polarizing plate of the present invention When included in the protective film for polarizing plate of the present invention, it is preferably contained in an amount of 0 to 35% by mass, particularly 5 to 30% by mass, based on the cellulose ester.
  • the protective film for polarizing plate of the present invention can contain an acrylic polymer having a weight average molecular weight in the range of 500 to 30,000. Above all, the weight obtained by copolymerizing ethylenically unsaturated monomer Xa having no aromatic ring and hydrophilic group in the molecule and ethylenically unsaturated monomer Xb having no aromatic ring and having a hydrophilic group in the molecule.
  • the acrylic copolymer can be added in the range of 1 to 30% by mass with respect to the cellulose ester.
  • the protective film for polarizing plate of the present invention preferably contains an ultraviolet absorber, and examples of the ultraviolet absorber used include benzotriazole-based, 2-hydroxybenzophenone-based or salicylic acid phenyl ester-based ones.
  • 2- (5-methyl-2-hydroxyphenyl) benzotriazole 2- [2-hydroxy-3,5-bis ( ⁇ , ⁇ -dimethylbenzyl) phenyl] -2H-benzotriazole
  • 2- (3 Triazoles such as 5-di-t-butyl-2-hydroxyphenyl) benzotriazole, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone And benzophenones.
  • ultraviolet absorbers having a molecular weight of 400 or more are less likely to volatilize at a high boiling point and are difficult to disperse even during high-temperature molding, so that the weather resistance is effectively improved with a relatively small amount of addition. be able to.
  • Examples of the ultraviolet absorber having a molecular weight of 400 or more include 2- [2-hydroxy-3,5-bis ( ⁇ , ⁇ -dimethylbenzyl) phenyl] -2-benzotriazole, 2,2-methylenebis [4- (1, 1,3,3-tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol], bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis ( Hindered amines such as 1,2,2,6,6-pentamethyl-4-piperidyl) sebacate and 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butylmalonic acid Bis (1,2,2,6,6-pentamethyl-4-piperidyl), 1- [2- [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxy] Such as til] -4- [3- (3,5-di-tert-butyl
  • 2- [2-hydroxy-3,5-bis ( ⁇ , ⁇ -dimethylbenzyl) phenyl] -2-benzotriazole and 2,2-methylenebis [4- (1,1,3,3- Tetrabutyl) -6- (2H-benzotriazol-2-yl) phenol] is particularly preferred.
  • the protective film for polarizing plates of the present invention can contain other plasticizers as necessary to obtain the effects of the present invention.
  • a polyhydric alcohol ester plasticizer preferably, 1) a polyhydric alcohol ester plasticizer, 2) a polycarboxylic acid ester plasticizer, 3) a glycolate plasticizer, 4) a phthalate plasticizer, 5) a fatty acid ester plasticizer, 6 ) It is selected from phosphate plasticizers and the like.
  • These plasticizers are preferably used in the range of 1 to 30% by mass with respect to the cellulose ester.
  • the polyhydric alcohol ester plasticizer is an ester compound of a polyhydric alcohol represented by the following general formula (3).
  • R 1- (OH) n (Wherein R 1 represents an n-valent organic group, and n represents a positive integer of 2 or more)
  • Preferred examples of the polyhydric alcohol include ethylene glycol, propylene glycol, trimethylolpropane, and pentaerythritol.
  • monocarboxylic acid used in the polyhydric alcohol ester known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid, and the like can be used.
  • a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used. More preferably, it has 1 to 20 carbon atoms, and particularly preferably 1 to 10 carbon atoms.
  • Examples of preferred alicyclic monocarboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, and derivatives thereof.
  • aromatic monocarboxylic acids examples include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and two or more benzene rings such as biphenylcarboxylic acid, naphthalenecarboxylic acid, and tetralincarboxylic acid.
  • benzoic acid which has, or derivatives thereof can be mentioned.
  • benzoic acid is preferred.
  • the molecular weight of the polyhydric alcohol ester is preferably in the range of 300 to 1500, more preferably in the range of 350 to 750.
  • the carboxylic acid used for the polyhydric alcohol ester may be one kind or a mixture of two or more kinds. Moreover, all the OH groups in the polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are.
  • ester compound (A) represented by the general formula (I) described in JP-A-2008-88292.
  • the polyvalent carboxylic acid ester compound is composed of an ester of a divalent or higher, preferably a divalent to 20-valent polyvalent carboxylic acid and an alcohol.
  • the aliphatic polyvalent carboxylic acid is preferably divalent to 20-valent, and in the case of an aromatic polyvalent carboxylic acid or an alicyclic polyvalent carboxylic acid, it is preferably divalent to 20-valent.
  • the polyvalent carboxylic acid is represented by the following general formula (4).
  • R 2 (COOH) m (OH) n (Wherein R 2 is an (m + n) -valent organic group, m is a positive integer of 2 or more, n is an integer of 0 or more, a COOH group is a carboxy group, and an OH group is an alcoholic or phenolic hydroxyl group)
  • R 2 is an (m + n) -valent organic group, m is a positive integer of 2 or more, n is an integer of 0 or more, a COOH group is a carboxy group, and an OH group is an alcoholic or phenolic hydroxyl group
  • preferable polyvalent carboxylic acids include the following.
  • Divalent or higher aromatic polyvalent carboxylic acids or derivatives such as phthalic acid, terephthalic acid, isophthalic acid, trimellitic acid, trimesic acid, pyromellitic acid, succinic acid, adipic acid, azelaic acid, sebacic acid, oxalic acid
  • 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 can be preferably used.
  • alcohol used in the polyvalent carboxylic acid ester compound that can be used in the present invention known alcohols and phenols can be used.
  • an aliphatic saturated alcohol having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used.
  • phenol examples include phenol, paracresol, dimethyl Phenol etc. can be used individually or in combination of 2 or more types.
  • ester compound (B) represented by the general formula (II) described in JP-A-2008-88292.
  • the molecular weight of the polyvalent carboxylic acid ester compound is not particularly limited, but is preferably in the range of 300 to 1000, more preferably in the range of 350 to 750.
  • the alcohol used for the polyvalent carboxylic acid ester may be one kind or a mixture of two or more kinds.
  • the acid value of the polycarboxylic acid ester compound is preferably 1 mgKOH / g or less, and more preferably 0.2 mgKOH / g or less.
  • the acid value means the number of milligrams of potassium hydroxide necessary for neutralizing the acid (carboxy group present in the sample) contained in 1 g of the sample.
  • the acid value is measured according to JIS K0070.
  • the glycolate plasticizer is not particularly limited, but alkylphthalylalkyl glycolates can be preferably used.
  • alkylphthalyl alkyl glycolates include methyl phthalyl methyl glycolate, ethyl phthalyl ethyl glycolate, propyl phthalyl propyl glycolate, butyl phthalyl butyl glycolate, octyl phthalyl octyl glycolate and the like.
  • phthalate ester plasticizer examples include diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, dioctyl phthalate, dicyclohexyl phthalate, and dicyclohexyl terephthalate.
  • citrate plasticizer examples include acetyltrimethyl citrate, acetyltriethyl citrate, and acetyltributyl citrate.
  • fatty acid ester plasticizers examples include butyl oleate, methylacetyl ricinoleate, and dibutyl sebacate.
  • phosphate ester plasticizers examples include triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, and the like.
  • antioxidants can be added to the protective film for polarizing plate of the present invention in order to improve the thermal decomposability and thermal colorability during molding. It is also possible to add an antistatic agent to give the optical film antistatic performance.
  • a flame retardant acrylic resin composition containing a phosphorus flame retardant may be used.
  • Phosphorus flame retardants used here include red phosphorus, triaryl phosphate ester, diaryl phosphate ester, monoaryl phosphate ester, aryl phosphonate compound, aryl phosphine oxide compound, condensed aryl phosphate ester, halogenated alkyl phosphorus. Examples thereof include one or a mixture of two or more selected from acid esters, halogen-containing condensed phosphate esters, halogen-containing condensed phosphonate esters, halogen-containing phosphite esters, and the like.
  • triphenyl phosphate 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, phenylphosphonic acid, tris ( ⁇ -chloroethyl) phosphate, tris (dichloropropyl) Examples thereof include phosphate and tris (tribromoneopentyl) phosphate.
  • the production method of the protective film for polarizing plates of this invention is not particularly limited, but is preferably a production method having at least the following steps (1) to (3).
  • PrA degree of propionyl group substitution
  • AcB degree of propionyl group substitution
  • PrB degree of propionyl group substitution
  • Organic solvent useful for forming the dope when the protective film for polarizing plate of the present invention is produced by the solution casting method is not limited as long as it dissolves a plurality of polymers and other additives used at the same time. Can be used.
  • methylene chloride as a non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, nitroethane, etc.
  • Methylene chloride, methyl acetate, ethyl acetate and acetone can be preferably used.
  • the dope preferably contains 1 to 40% by mass of a linear or branched aliphatic alcohol having 1 to 4 carbon atoms.
  • a linear or branched aliphatic alcohol having 1 to 4 carbon atoms.
  • it is a dope composition in which at least 15 to 45 mass% in total of a sea polymer and an island polymer are dissolved in a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. It is preferable.
  • linear or branched aliphatic alcohol having 1 to 4 carbon atoms examples include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Ethanol is preferred because of the stability of these dopes, the relatively low boiling point, and good drying properties.
  • FIG. 2 is a diagram schematically showing an example of a dope preparation step, a casting step, and a drying step of a solution casting film forming method preferable for the present invention.
  • a method carried out at normal pressure a method carried out below the boiling point of the main solvent, a method carried out under pressure above the boiling point of the main solvent, JP-A-9-95544, JP-A-9-95557, or Various dissolution methods such as a method using a cooling dissolution method as described in JP-A-9-95538 and a method using a high pressure as described in JP-A-11-21379 can be used.
  • a method in which pressure is applied as described above is preferable.
  • a filter medium After dissolving the polymer and additives, it is filtered through a filter medium, defoamed, and sent to the next process with a liquid feed pump.
  • a filter medium having a collected particle diameter of 0.5 to 5 ⁇ m and a drainage time of 10 to 25 sec / 100 ml.
  • the main dope is filtered by the main filter 3, and an ultraviolet absorbent additive solution is added in-line through the conduit 16 to the main dope.
  • the main dope may contain about 10 to 50% by weight of recycled material.
  • the return material is a product obtained by finely pulverizing the optical film, which is generated when the optical film is formed, and is obtained by cutting off both sides of the film, or by using an optical film original that has been speculated out due to scratches, etc. .
  • An endless metal belt 31 such as a stainless steel belt or a rotating metal drum that feeds the dope to a pressure die 30 through a liquid feed pump (for example, a pressurized metering gear pump) and transfers it indefinitely.
  • a liquid feed pump for example, a pressurized metering gear pump
  • ⁇ Pressure dies that can adjust the slit shape of the die base and make the film thickness uniform are preferred.
  • the pressure die include a coat hanger die and a T die, and any of them is preferably used.
  • the surface of the metal support is a mirror surface.
  • two or more pressure dies may be provided on the metal support, and the dope amount may be divided and stacked. Or it is also preferable to obtain the film of a laminated structure by the co-casting method which casts several dope simultaneously.
  • Solvent evaporation step In the step of evaporating the solvent by heating the web (the dope is cast on the casting support and the formed dope film is called “web”) on the casting support. is there.
  • the liquid temperature to be brought into contact with the back surface of the support in this solvent evaporation step, the contact time with the support, and the like may be appropriately adjusted.
  • Peeling process It is the process of peeling the web which the solvent evaporated on the metal support body in a peeling position. The peeled web is sent to the next process.
  • the temperature at the peeling position on the metal support is preferably 10 to 40 ° C., more preferably 11 to 30 ° C.
  • the amount of residual solvent at the time of peeling of the web on the metal support at the time of peeling is preferably peeled in the range of 5 to 120% by mass depending on the strength of drying conditions, the length of the metal support, and the like. .
  • the amount of residual solvent used in the present invention can be expressed by the following formula.
  • Residual solvent amount (% by mass) ⁇ (MN) / N ⁇ ⁇ 100
  • M is the mass of the web at an arbitrary point
  • N is the mass when M is dried at 110 ° C. for 3 hours.
  • a drying device 35 that alternately passes the web through rollers arranged in the drying device and / or a tenter stretching device 34 that clips and transports both ends of the web with clips are used. And dry the web.
  • the drying means is generally to blow hot air on both sides of the web, but there is also a means to heat by applying microwaves instead of wind. Too rapid drying tends to impair the flatness of the finished film. Drying at a high temperature is preferably performed from about 8% by mass or less of the residual solvent. Throughout, drying is generally performed at 40-250 ° C.
  • tenter stretching apparatus When using a tenter stretching apparatus, it is preferable to use an apparatus that can independently control the film gripping length (distance from the start of gripping to the end of gripping) left and right by the left and right gripping means of the tenter. In the tenter process, it is also preferable to intentionally create sections having different temperatures in order to improve planarity.
  • the stretching operation may be performed in multiple stages, and it is also 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 added to any one of the stages. Is also possible. That is, for example, the following stretching steps are possible.
  • Simultaneous biaxial stretching includes stretching in one direction and contracting the other while relaxing the tension.
  • the stretching ratio is preferably from 1.03 to 1.2 times in the width direction, the longitudinal direction, particularly the width direction, in order to form the sea-island structure according to the present invention with desired irregularities. If the stretching is performed less than 1.03 times or more than 1.2 times, the sea-island structure is difficult to obtain.
  • the protective film for polarizing plate of the present invention is preferably stretched at a temperature at which the stretching temperature T satisfies Tg (A) ⁇ T ⁇ Tg (B). Therefore, among the resins forming the sea-island structure, the resin (cellulose ester resin B) constituting the island has a higher glass transition temperature than the resin constituting the sea (cellulose ester resin A).
  • the temperature when performing tenter stretching is preferably in the range of 30 to 200 ° C, more preferably in the range of 100 to 200 ° C.
  • thermocontrol during stretching known means such as hot air or microwave can be used.
  • the temperature distribution in the width direction of the atmosphere is small from the viewpoint of improving the uniformity of the film.
  • the temperature distribution in the width direction in the tenter process is preferably within ⁇ 5 ° C, and within ⁇ 2 ° C. Is more preferable, and within ⁇ 1 ° C is most preferable.
  • Winding process This is a process in which the amount of residual solvent in the web becomes 2% by mass or less, and is taken up by the winder 37 as a film, and the dimensional stability is achieved by setting the residual solvent amount to 0.4% by mass or less. Can be obtained. It is particularly preferable to wind up at 0.00 to 0.10% by mass.
  • a generally used one may be used, and there are a constant torque method, a constant tension method, a taper tension method, a program tension control method with a constant internal stress, etc., and these may be used properly.
  • the protective film for polarizing plate of the present invention preferably has an average film thickness in the range of 20 to 85 ⁇ m from the viewpoint of the function as a protective film for polarizing plate, curling of the polarizing plate, and the like.
  • the film thickness is measured at an arbitrary 10 points in the film plane with a contact-type film thickness meter, and an average value is taken.
  • the polarizing plate protective film of the present invention is preferably a long film, and specifically shows a film having a thickness of about 100 m to 5000 m, usually in the form of a roll.
  • the width of the film is preferably 1.3 to 4 m, and more preferably 1.4 to 3 m.
  • a polarizing plate is mainly comprised by the protective film for two polarizing plates which protects both the front side and back side of a polarizer.
  • the polarizing plate protective film of the present invention is used for at least one of the two polarizing plate protective films sandwiching the polarizer from both sides. Since the film of the present invention has not only a moire eliminating ability but also a protective film property, the manufacturing cost of the polarizing plate can be reduced.
  • the polarizing plate of the present invention can be used as a polarizing plate on the backlight side of the image display device or a polarizing plate on the viewing side. When used for the backlight unit-side polarizing plate, the film of the present invention is disposed so that it is closest to the backlight.
  • the film of the present invention When used for the polarizing plate on the viewing side, the film of the present invention is disposed so as to be the outermost layer.
  • the film of the present invention When used as a polarizing plate on the viewing side, reflection of external light and the like can be prevented, and a polarizing plate that can improve contrast in an environment with external light (light room) can be obtained.
  • ⁇ Liquid crystal display device> As an example of the configuration of a conventional liquid crystal display device, in the direct type, as shown in FIG. 3A, from the light source side, [light source 1a / diffusion plate 3a / light collecting sheet 4a (prism sheet etc.) / Upper diffusion sheet 5a / Liquid crystal panel 12a (polarizer 10a / protective film (retardation film or the like) 9a / substrate 8a / liquid crystal cell 7a / protective film 11a)], which is mainly used in a large LCD such as a television.
  • the light source 1a is composed of a light emission source 2a and a light guide plate 13a, and is mainly used for small LCDs for monitors and mobile applications.
  • the lower diffusion sheet is an optical sheet having strong light diffusibility mainly for reducing in-plane luminance unevenness of the backlight unit (BLU) 6a, and the condensing sheet transmits diffused light in the front direction of the liquid crystal display device (display device plane).
  • the upper diffusion sheet is used to reduce the moire generated by a periodic structure such as a prism sheet that is a light condensing sheet or a pixel in a liquid crystal cell, and the lower diffusion sheet. This optical sheet is used to further reduce in-plane luminance unevenness that cannot be removed by the sheet.
  • the protective film for polarizing plate of the present invention can be manufactured without requiring a coating process or a complicated process, and the cost of the entire liquid crystal display device can be reduced by adopting a configuration in which the upper diffusion sheet is removed in this way. it can.
  • Liquid crystal cell display methods include twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), in-plane switching (IPS), and optically compensated bend cells (OCB). It can be preferably used for a transmissive, reflective, or transflective liquid crystal display device.
  • TN twisted nematic
  • STN super twisted nematic
  • VA vertical alignment
  • IPS in-plane switching
  • OOB optically compensated bend cells
  • CCFL Cold Cathode Fluorescent Lamp, Cold Cathode Tube
  • HCFL Hot Cathode Fluorescent Lamp, Hot Cathode Tube
  • LED Light Emitting Diode, Light Emitting Diode
  • OLED Organic light-emitting diode organic light-emitting diodes, inorganic electroluminescence, and the like can be preferably used.
  • the list of used cellulose ester resins is shown in Table 1.
  • the weight average molecular weight (Mw) of the used cellulose ester resin was measured using a gel permeation measuring device (GPC).
  • the measurement conditions are as follows. Solvent: Methylene chloride Column: Shodex K806, K805, K803G (Used by connecting three Showa Denko Co., Ltd.) Column temperature: 25 ° C Sample concentration: 0.1% by mass Detector: RI Model 504 (manufactured by GL Sciences) Pump: L6000 (manufactured by Hitachi, Ltd.) Flow rate: 1.0ml / min
  • Example 1 A main dope having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. Cellulose ester, sugar ester compound, and UV absorber were charged into a pressure dissolution tank containing a solvent while stirring. This was completely dissolved while stirring, and Azumi Filter Paper No. The main dope was prepared by filtration using 244.
  • Example 1 After evaporating the solvent on the belt, the web is peeled off from the stainless steel belt, and drying is completed while the drying zone at 120 ° C. is conveyed by a number of rollers, and winding is performed.
  • the film of Example 1 was obtained.
  • the Z value and Y value defined by the following formulas 1 and 2 were 3.49 and 3.34, respectively, and the relationship of Y ⁇ Z was satisfied.
  • Example 2 A dope is produced in the same manner as in Example 1, cast on a stainless steel belt using a belt casting apparatus, and after evaporating the solvent, the web is peeled from the stainless steel belt and conveyed using a tenter. The film was stretched 1.1 times in the width direction at 170 ° C. Then, drying was terminated while conveying a 120 degreeC drying zone with many rollers, and the film of Example 2 of this invention with an average film thickness of 40 micrometers was obtained.
  • Example 1 A main dope was produced in the same manner as in Example 1 except that the main dope of Example 1 was changed to the following composition.
  • the web After evaporating the solvent on the stainless steel belt, the web was peeled from the stainless steel belt and stretched 1.1 times in the width direction at 170 ° C. using a tenter while being conveyed. Thereafter, drying was completed while being transported through a 120 ° C. drying zone with a large number of rollers, and the film was wound up to obtain a film of Comparative Example 1 having an average thickness of 40 ⁇ m.
  • the web After evaporating the solvent on the stainless steel belt, the web was peeled from the stainless steel belt and stretched 1.1 times in the width direction at 170 ° C. using a tenter while being conveyed. Thereafter, drying was completed while being transported through a 120 ° C. drying zone with a number of rollers, and the film was wound up to obtain a film of Comparative Example 2 having an average film thickness of 40 ⁇ m.
  • Example 3 A main dope was produced in the same manner as in Example 1 except that the main dope of Example 1 was changed to the following composition.
  • the web was peeled off from the stainless steel belt, and the drying was completed while being transported by a large number of rollers through a 120 ° C. drying zone, and the average film thickness was 40 ⁇ m. A film of 3 was obtained.
  • Example 4 A dope was produced in the same manner as in Example 3, cast on a stainless steel belt using a belt casting apparatus, and after evaporating the solvent, the web was peeled from the stainless steel belt and conveyed using a tenter. The film was stretched 1.1 times in the width direction at 160 ° C. Then, drying was terminated while conveying a 120 degreeC drying zone with many rollers, and the film of Example 4 of this invention with an average film thickness of 40 micrometers was obtained.
  • Example 5 A main dope was produced in the same manner as in Example 1 except that the main dope of Example 1 was changed to the following composition.
  • the web After evaporating the solvent on the stainless steel belt, the web was peeled off from the stainless steel belt, and the drying was completed while being transported by a large number of rollers through a 120 ° C. drying zone, and the average film thickness was 40 ⁇ m. 5 films were obtained.
  • Example 6 A dope was produced in the same manner as in Example 5, cast on a stainless steel belt using a belt casting apparatus, and after evaporating the solvent, the web was peeled from the stainless steel belt and conveyed using a tenter. The film was stretched 1.1 times in the width direction at 180 ° C. Then, drying was terminated while conveying a 120 degreeC drying zone with many rollers, and the film of Example 6 of this invention with an average film thickness of 40 micrometers was obtained.
  • Example 7 A main dope was produced in the same manner as in Example 1 except that the main dope of Example 1 was changed to the following composition.
  • the web was peeled from the stainless steel belt and stretched 1.1 times in the width direction at 185 ° C. using a tenter while being conveyed. Then, drying was terminated and wound up, conveying a 120 degreeC drying zone with many rollers, and the film of Example 7 with an average film thickness of 40 micrometers was obtained.
  • Example 8 A main dope was produced in the same manner as in Example 1 except that the main dope of Example 1 was changed to the following composition.
  • the web was peeled from the stainless steel belt and stretched 1.1 times in the width direction at 180 ° C. using a tenter while being conveyed. Then, drying was completed and wound up, conveying a 120 degreeC drying zone with many rollers, and the film of Example 8 with an average film thickness of 40 micrometers was obtained.
  • evaluation film refers to the film produced in Examples 1 to 8 and Comparative Examples 1 and 2.
  • ⁇ L (%) 100 ⁇
  • ⁇ L is less than 0.15 and wet heat dimensional change is small ⁇ ; ⁇ L is 0.15 or more, wet heat dimensional change is large and NG level (moire eliminating ability)
  • a commercially available notebook personal computer (Sumsun R430) was disassembled, the backlight unit was taken out, and two prism sheets incorporated were taken out. The two prism sheets were arranged on the Schaukasten in the same order and in the same positional relationship as those incorporated in the backlight unit. In this state, when viewed in a dark room, strong moire fringes were observed. As shown in FIG.
  • an evaluation film cut into a size of 10 cm ⁇ 10 cm is further placed on the surface prism sheet so that the uneven surface of the film faces the prism sheet, observed in a dark room, and moire.
  • the degree of elimination of stripes was evaluated according to the following criteria.
  • the "commercial item" used for the criteria of ⁇ and ⁇ is arranged so as to be adjacent to the backlight among the films used as protective films for the rear side (backlight side) polarizing plate of the notebook computer.
  • the anti-glare film was peeled off from the liquid crystal cell of the above-mentioned notebook personal computer, immersed in pure water for 4 hours, and then the polarizer was peeled off from the film. Used after conditioning to 55% RH.
  • Step 1> A polyvinyl alcohol film having a thickness of 50 ⁇ m was uniaxially stretched in the film forming direction (temperature: 110 ° C., stretch ratio: 5 times). This was immersed in an aqueous solution composed of 0.075 g of iodine, 6 g of potassium iodide, and 100 g of water for 60 seconds, and then immersed in an aqueous solution of 68 ° C. composed of 6 g of potassium iodide, 7.5 g of boric acid, and 100 g of water. . This was washed with water and dried to obtain a polarizer. This polarizer had an absorption axis in the film forming direction.
  • Step 2> The prepared evaluation film was immersed in a 4N aqueous potassium hydroxide solution at 50 ° C. for 60 seconds as a protective film for polarizing plate, then washed with water and dried to saponify the surface to be bonded to the polarizer.
  • Step 3> The polarizer was immersed in a polyvinyl alcohol adhesive tank having a solid content of 2% by mass for 1 to 2 seconds.
  • Step 4> The excess adhesive adhering to the polarizer in Step 3 was lightly wiped off, and this was placed on the surface of the evaluation film saponified in Step 2 and further treated in Step 2 as a protective film for the polarizing plate on the opposite side.
  • the cellulose ester film 4UY was laminated so that the saponified surface was in contact with the polarizer to obtain a polarizing plate.
  • Step 5 The polarizing plate in which the film and the polarizer were laminated in Step 4 was bonded at a pressure of 20 to 30 N / cm 2 and a conveyance speed of about 2 m / min.
  • Step 6> The polarizing plates bonded in step 5 are each cut to a size of 5 cm ⁇ 7 cm, and both ends on the long side of the obtained polarizing plate pieces are firmly sandwiched between clips, and the polarizing plate pieces together with the clips are placed in a 60 ° C. oven. It was hung vertically and dried.
  • the sample was taken out from the oven and fully conditioned in an environment of 23 ° C. and 55% RH, and then the test was performed by peeling the evaluation film from the polarizer by hand from the end of the polarizing plate. The adhesion between the film and the polarizer was evaluated.
  • polyester compound B 251 g of 1,2-propylene glycol, 278 g of phthalic anhydride, 91 g of adipic acid, 610 g of benzoic acid, 0.191 g of tetraisopropyl titanate as an esterification catalyst, 2 L four-neck equipped with thermometer, stirrer, and slow cooling tube The flask is charged and gradually heated with stirring until it reaches 230 ° C. in a nitrogen stream. After dehydration condensation reaction for 15 hours, polyester compound B was obtained by distilling off unreacted 1,2-propylene glycol under reduced pressure at 200 ° C. after completion of the reaction. The acid value was 0.10 and the number average molecular weight was 450.
  • the main dope was produced in the same manner as in Example 1 except that the main dope of Example 1 was changed to the following composition.
  • the web was peeled from the stainless steel belt and stretched 1.1 times in the width direction at 180 ° C. using a tenter while being conveyed. Then, drying was terminated and wound up, conveying a 120 degreeC drying zone with many rollers, and the film of Example 9 with an average film thickness of 40 micrometers was obtained.
  • a dope was prepared in the same manner as in Example 9 using the cellulose ester resin A and the cellulose ester resin B described in Table 3.
  • the Z value and Y value defined by the above formulas 1 and 2 are as shown in Table 3, respectively, and both have a relationship of Y> Z.
  • the dope was cast on a stainless steel belt using a belt casting apparatus. After evaporating the solvent on the stainless steel belt, the web was peeled from the stainless steel belt and stretched in the width direction at the temperatures and stretch ratios shown in Table B using a tenter while being conveyed. Thereafter, drying was completed while the drying zone at 120 ° C. was conveyed by a number of rollers, and the film was wound up to obtain films of Comparative Examples 3, 4, 5, 6, and 8 having an average thickness of 40 ⁇ m.
  • Example 9 The films of Example 9 and Comparative Examples 3 to 9 produced as described above were evaluated for wet heat dimensional fluctuation, moire eliminating ability, and polarizer adhesion. The results are shown in Table 3.
  • the fine particle dispersion 1 was slowly added to the dissolution tank containing methylene chloride with sufficient stirring. Further, the particles were dispersed by an attritor so that the secondary particles had a predetermined particle size. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution 1.
  • a main dope having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. Cellulose acetate was added to a pressurized dissolution tank containing a solvent while stirring. This is completely dissolved with heating and stirring. This was designated as Azumi Filter Paper No. The main dope was prepared by filtration using 244.
  • the solvent was evaporated until the amount of residual solvent in the cast (cast) film reached 75%, and then peeled off from the stainless steel belt support with a peeling tension of 130 N / m.
  • the film is stretched using a tenter stretching apparatus, and then dried by being transported in a drying zone set at 130 ° C. for 30 minutes to have a film thickness of 40 ⁇ m having a width of 2 m, a width of 1 cm at an end, and a height of 8 ⁇ m.
  • No. retardation film R was prepared and wound up at 5000 m.
  • Retardation values Ro (590) and Rt (590) of the retardation film R were 20 nm and 110 nm, respectively.
  • the above Ro (590) and Rt (590) are defined by the following formulas, and were measured using a phase difference measuring device (manufactured by Oji Scientific Co., Ltd., KOBRA-WXK).
  • Step 1> A polyvinyl alcohol film having a thickness of 50 ⁇ m was uniaxially stretched in the film forming direction (temperature: 110 ° C., stretch ratio: 5 times). This was immersed in an aqueous solution composed of 0.075 g of iodine, 6 g of potassium iodide, and 100 g of water for 60 seconds, and then immersed in an aqueous solution of 68 ° C. composed of 6 g of potassium iodide, 7.5 g of boric acid, and 100 g of water. . This was washed with water and dried to obtain a polarizer. This polarizer had an absorption axis in the film forming direction.
  • Step 2> The prepared evaluation film was immersed in a 4N aqueous potassium hydroxide solution at 50 ° C. for 60 seconds as a protective film for polarizing plate, then washed with water and dried to saponify the surface to be bonded to the polarizer.
  • the retardation film R produced above was saponified as a protective film for the polarizing plate on the opposite side.
  • Step 3> The polarizer was immersed in a polyvinyl alcohol adhesive tank having a solid content of 2% by mass for 1 to 2 seconds.
  • Step 4> Excess adhesive adhered to the polarizer in Step 3 is gently wiped off, and this is placed on the bonding surface of the evaluation film saponified in Step 2, and further processed in Step 2 as a protective film for the polarizing plate on the opposite side.
  • the retardation film R was laminated so that the saponified surface was in contact with the polarizer, and a polarizing plate was obtained.
  • Step 5 The polarizing plate in which the film and the polarizer were laminated in Step 4 was bonded at a pressure of 20 to 30 N / cm 2 and a conveyance speed of about 2 m / min.
  • Step 6 Samples obtained by laminating the polarizer, the evaluation film, and the optical film R prepared in Step 5 in a drier at 80 ° C. by roll-to-roll were dried for 2 minutes, and each of Examples 1 to 9 and Comparative Examples 1 to 9 was used. A corresponding polarizing plate was prepared.
  • the rear side polarizing plate of a commercially available liquid crystal monitor (manufactured by Samsung, SyncMaster 743BM) was peeled off, and the polarizing plate prepared above was bonded instead. However, when laminating to the liquid crystal cell, it is laminated so that the surface of the evaluation film faces the backlight side and the absorption axis faces in the same direction as the polarizing plate that has been preliminarily bonded. did.
  • the backlight unit has a configuration of light guide plate / lower diffusion sheet / prism sheet / prism sheet in order from the light source side. Liquid crystal display devices 1 to 9 of the present invention and comparative liquid crystal display devices 1 to 9 corresponding to the films of Examples 1 to 9 and Comparative Examples 1 to 9 were produced.
  • the protective film for a polarizing plate having a concavo-convex shape of the present invention is excellent in adhesion with a polarizer and dimensional stability under high temperature and high humidity, and excellent in having no moire fringes when used on the backlight side of a liquid crystal display device. Therefore, it is suitable for polarizing plates and liquid crystal display devices.

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Abstract

La présente invention aborde le problème de procurer un film protecteur pour une lame de polariseur ayant une excellente adhésion avec un polariseur, une excellente stabilité dimensionnelle aux températures élevées et sous une humidité élevée, et une excellente performance de diffusion de lumière sans frange de moiré lorsqu'il est utilisé sur le côté en contre-jour d'un dispositif d'affichage à cristaux liquides. Le film protecteur pour une lame de polariseur ayant une surface irrégulière de la présente invention est caractérisé en ce qu'il comprend une résine d'ester de cellulose (A) et une résine d'ester de cellulose (B), où (A) la résine (A) est un acétate propionate de cellulose, (B) le rapport massique de la résine (A) et de la résine (B) se situe dans une plage de A/B = 60/40 à 95/5, et (C) (Z) tel que défini par la formule 1 se rapportant au degré de substitution par propionyle (PrA) de la résine (A) et (Y) tel que défini par la formule 2 se rapportant au degré de substitution par acétyle (AcB) et au degré de substitution par propionyle (PrB) de la résine (B) satisfont Y < Z à l'intérieur d'une plage de PrA > 0,5. Formule 1: Z = 0,7 x (PrA) + 1,7, Formule 2: Y = 2 x (PrB)+(AcB).
PCT/JP2012/066891 2011-07-07 2012-07-02 Film protecteur pour lame de polariseur, son procédé de fabrication, lame de polariseur et dispositif d'affichage à cristaux liquides WO2013005716A1 (fr)

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JP2020162838A (ja) * 2019-03-29 2020-10-08 株式会社サンセイアールアンドディ 遊技機

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JP2009053583A (ja) * 2007-08-29 2009-03-12 Konica Minolta Opto Inc 異方性散乱素子、偏光板および液晶表示装置
JP2010164931A (ja) * 2008-12-15 2010-07-29 Fujifilm Corp 液晶表示装置および液晶表示装置の製造方法

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JP2010164931A (ja) * 2008-12-15 2010-07-29 Fujifilm Corp 液晶表示装置および液晶表示装置の製造方法

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