TW201043442A - Optical film manufacturing method, optical film, polarizing plate, and liquid crystal display device - Google Patents

Abstract

Disclosed is a method for manufacturing an optical film for which a fused material adhering to the perimeter of a lip part does not degrade due to oxidation and form an aggregate, and for which sublimates from the fused material do not adhere to the perimeter of the lip part, and for which striped noise is not generated; further disclosed are an optical film manufactured with said method, and a polarizing plate and a liquid crystal display device for which said optical film is used as a protective film. In an extrusion process, an inert gas with a temperature of not less than 110 DEG C and not more than 300 DEG C is supplied to the lip part of a casting die from a supply nozzle.

Description

201043442 SUMMARY OF THE INVENTION Technical Field The present invention relates to a method for producing an optical film, an optical film, a polarizing plate using the optical film, and a liquid crystal display device. • [Prior Art] Image processing devices such as word processors or personal computers, TVs, etc. use 0 many optical films. For example, a polarizing plate provided on both sides of a liquid crystal cell used in a liquid crystal image display device (L C D ) is used as a protective film to be bonded to both surfaces of a polarizer. Since the polarizing plate passes only the light of the deflecting surface in a certain direction, the performance of the LCD is greatly affected by the performance of the polarizing plate, which is an important function for visualizing the change of the liquid crystal alignment by the electric field. Therefore, the optical properties required for the protective film attached to both sides of the polarizer are also increased. Such optical films have heretofore been mainly produced by solution casting. The solution casting method is a film forming method in which a resin is dissolved in a solvent and cast to obtain a film shape, and then the solvent is evaporated and dried to obtain a film. Since the film formed by the solution casting method has a high planarity, a uniform high-quality image display device can be obtained by using the film. However, since the solution casting method uses a large amount of an organic solvent, it is necessary to dry and recover the organic solvent. Therefore, in recent years, the manufacture of optical films has been attempted by a melt casting method in which a resin is melt-formed. For example, when a deuterated cellulose film used for a protective film is used, the main resin of deuterated cellulose is melt-formed. Addition of melted material of deuterated cellulose -5 - 201043442 Various additives for improving the properties of a protective film of a film-modified or polarizing plate. For example, improved film properties such as plasticizers, antioxidants, ultraviolet absorbers, and matting agents are added. However, in the case of a melt casting method in which a constituent material of such a deuterated cellulose film is melted at a high temperature and extruded from a lip of a casting die onto a cooling roll to form a film by cooling and solidification, in a casting die Aggregates adhere to the periphery of the lip, and the film thickness of the melt extruded by the extrusion process is not uniform, and the produced film has a problem of causing line-like interference (uneven film thickness). The lip is meant to be melted by a casting die.

ί I The constituent part of the outlet portion of the resin extrusion, and the periphery of the lip refers to the periphery of the outlet where the molten resin is extruded by the casting die. The cause of the agglomerates attached to the periphery of the lip is that the sublimate produced by the melt extruded from the casting die adheres to the periphery of the lip for the reason of this - 〇 · A method for preventing the adhesion of such a sublimate A method of providing a suction nozzle in the vicinity of a lip to forcibly exhaust the produced sublimate (Patent Document 1)

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[PRIOR ART DOCUMENT] [Patent Document] [Patent Document] Japanese Patent Laid-Open Publication No. 11-48306 [Draft of the Invention] [Problems to be Solved by the Invention] -6 - 201043442 However, the method of Patent Document 1 cannot fully eliminate the lip. The agglomerates around the _, and the film has a problem of line-like interference. The inventors of the present invention carefully examined the cause of the occurrence of agglomerates other than the adhesion of the sublimate, and found that the molten material adhered to the periphery of the lip when it was taken out by the casting die. However, the part was oxidized and deteriorated to be agglomerated. Therefore, the object of the present invention is to provide that the melt adhered to the periphery of the lip does not oxidize and degrade to form an aggregate, and the sublimate from the melt melt does not adhere to the periphery of the lip, and no line-like interference occurs. A method for producing an optical film, an optical film produced by the method, and a polarizing plate and a liquid crystal display device using the optical film as a protective film. [Means for Solving the Problem] The subject of the present invention can be solved by the following means. A method for producing an optical film, comprising: an extrusion step of extruding a molten resin from a lip portion of a casting die into a film shape; and a film-like resin extruded by the extrusion step The method for producing an optical film for cooling step of cooling and solidifying a cooling roll is characterized in that the extrusion step is to supply an inert gas having a temperature of 1 l ° C or more and 300 ° C or less to the lip portion from a supply nozzle. 2. The method of producing an optical film according to the above item 1, wherein the step of supplying the inert gas is a wind speed of the inert gas ejected from the front end of the supply nozzle of 〇.3 m/s or more and 3 m/s or less. 3. The method of producing an optical film according to the above item 1, wherein the supply nozzle is provided with a heater to heat the inert gas. The method for producing an optical film according to any one of the above-mentioned items, wherein the suction nozzle is disposed on the downstream side in a direction in which the film-form resin to be extruded from the supply nozzle flows downward, and the suction nozzle is sucked by the The inert gas ejected from the nozzle is supplied. The method for producing an optical film according to any one of the preceding claims, wherein the inert gas is a nitrogen gas. 6. The method for producing an optical film according to any one of the above items 1 to 5, wherein the cooling step is a contact roll which presses a film-like resin on the cooling roll, and is pressed by the contact roll to form the film. The surface of the resin is smooth. The method for producing an optical film according to any one of the above items 1 to 6, wherein the resin is a deuterated cellulose or a cycloolefin polymer. 8. An optical film produced by the method for producing an optical film according to any one of the above items 1 to 7. 9. A polarizing plate' characterized in that the optical film of the above item 8 is used as a protective film for a polarizing plate. A liquid crystal display device is characterized in that the polarizing plate of the above item 9 is used. [Effect of the Invention] According to the present invention, when the molten resin is extruded by a casting die, an inert gas having a temperature of U0 °c or more and 300 ° C or less is supplied from the supply nozzle to the lip portion, thereby preventing the sublimate from adhering to the lip. Oxidative deterioration of the periphery of the part or the melt attached to the lip does not form aggregates around the lip. Therefore, it is possible to provide a method for producing an optical film having a uniform film thickness without causing line-like interference, an optical film produced by the production method, a polarizing plate for using the optical film for protecting a film, and a liquid crystal display device. * [Mode for Carrying Out the Invention] The method for producing an optical film of the present invention will be described below using an embodiment, but the present invention is not limited to the following embodiments. Fig. 1 is a schematic flow chart showing the overall configuration of an apparatus for carrying out the method for producing an optical film of the present invention. After the extrusion step is a method of mixing a film constituent material such as a raw material resin, the molten film constituent material is extruded onto the first cooling roll 5 by the casting die 4 using an extruder 1, and the cooling step is to contact the first cooling roll. The surface of the fifth cooling roller 7 and the third cooling roller 8 are sequentially contacted with the surface of the three cooling rollers, and solidified by cooling to form a film 10 . Next, the stripping step is to peel the film 1 by the peeling roller 9, and then the extending step is to longitudinally extend Q by the longitudinal stretching device 12a with a speed difference between the rolls, and then the both ends of the film are gripped by the lateral stretching device 12b. After the extension in the width direction, the winding step is wound by the winding device 16. In the method for producing an optical film of the present invention, when the molten resin is extruded from the casting die 4 in the extrusion step, 'the inert gas having a temperature of ll 〇 ° C or more and 300 ° C or less is supplied from the supply nozzle to the casting die 4 The lips. Figure 2 is a schematic cross-sectional view of the periphery of the lip portion of the present embodiment, showing the lip portions 3 3 and 34 of the flow pattern 4 and the supply nozzle 7 for supplying an inert gas to the pair of the lip portions 3 3 ' 3 4 〇, 70, suction nozzles 80, 80 that attract one pair of inert gases ejected from the supply nozzles 70, and a film-like molten resin (film 10) that flows out from the slits 33' 34 -9 - 201043442 slits 32 and The arrangement of the first cooling roll 5 of the molten resin and the flow of the inert gas are cooled. The pair of supply nozzles 70 and 70 are disposed on the respective surfaces of the film 1 of the molten resin which is disposed by the slits 3 2 formed by the lips 3 3 and 34 of the casting die 4, and are separated from each other. Distance d location. The front end portion (the film 10 side) of the supply nozzle 70 has a shape extending in the width direction of the film 10, specifically, an elongated rectangular opening similar to the slit 32 of the casting die 4. Further, as shown in Fig. 2, the side wall of the supply nozzle 70 in the longitudinal direction is formed by the side portion of the casting die 4 and the nozzle side plate 71. The end portion in the longitudinal direction (not shown) is closed by another member to avoid gas leakage from the supply nozzle. As shown in Fig. 2, inert gas is supplied from the supply pipe 73 to the supply nozzle 70. The pair of suction nozzles 80, 80 are disposed below the pair of supply nozzles 70, 70. The front end portions of the pair of suction nozzles 80' 80 are disposed on the downstream side in the direction in which the film 1 is turbulent with respect to the front end portions of the pair of supply nozzles 70, 70. The supplied inert gas system flows along the film 10, is sucked by the suction nozzle 80 disposed on the downstream side, and is discharged by the discharge pipe 8 2 . The shape of the opening of the end portion (the side of the film 1) of the suction nozzle 8 is a rectangle parallel to the width direction of the film 1 . Further, the side portions of the suction nozzles 80 are also formed by the nozzle side plates 71 and 81, and the end portions in the longitudinal direction (not shown) are closed by another member. As described above, the inert gas is supplied from the supply nozzle 70 to the lips 33, 34 of the casting die 4, and the molten resin extruded from the slits 3 2 does not adhere to the oxygen in the air even if it adheres to the periphery of the lip. Contact, therefore will not be oxidized, because -10- 201043442 This will not cure to agglomerate. Further, even if the sublimation component contained in the resin extruded from the slit 32 due to high temperature sublimation does not follow the flow of the inert gas, it does not accumulate in the lip portion. Therefore, the periphery of the lip does not cause the oxidative deterioration of the molten resin or the accumulation of sublimation components, etc., and the agglomeration of the film does not cause the longitudinal film shape due to the agglomerates attached to the lip. Both can produce high quality optical films. The temperature of the inert gas supplied to the lip by the supply nozzle 70 is 1 1 〇 ° C at 0 ° C or lower. When it is less than 110 ° C, the film is cooled, and there is a problem of uneven film thickness. When the temperature exceeds 300 ° C, the film is inferior due to thermal deterioration, and the inert gas of the lips 33 and 34 is supplied from the supply nozzle 70. For example, there are ruthenium, osmium, argon, krypton, xenon, krypton, nitrogen gas, etc., and in particular, the nitrogen gas is more inexpensive than its 'inert gas, so it is preferred. Further, in the embodiment of Fig. 2, the suction nozzle 80 is disposed in the vicinity of the supply nozzle 70, but the suction and discharge may be performed at a position away from the supply nozzle 70.较佳 It is preferable to avoid the increase in the inert gas concentration in the chamber in which the molten resin is cast into the first cooling roll 5 by the casting die 4, thereby ensuring the safety of the person working in the room. Further, the pair of supply nozzles 70 and the pair of suction nozzles 80 are disposed on the lip sides of both of the casting dies 4, but the adhesion of the aggregates is suppressed even on the lip side of either of the casting dies 4. The effect of the lip of the present invention. However, it is preferable to arrange it on the lip side of both sides of the casting die, which is more effective. The supply of the inert gas is a wind speed of the inert gas ejected from the front end of the supply nozzle 70, preferably 〇3 m/s or more and 3 m/s or less. Inert gas -11 - 201043442 The calculation of the wind speed is obtained by dividing the supply amount Wm3/s of the inert gas of the supply pipe 73 by the opening area Sm2 of the front end of the supply nozzle 70. When the wind speed of the inert gas is within the above range, the wind speed of the inert gas is not too small 'and the possibility of oxygen-free mixing into the lip or sublimation component attached to the lip' and the wind speed of the inert gas is too large, and the disturbance is squeezed. Since the flow of the film-formed molten resin is produced, it is preferable to produce an optical film having a uniform strip thickness and a uniform film thickness. The wind speed is preferably uniform in the width direction, and the deviation of the wind speed in the width direction is preferably within ±30%. More preferably less than 10%. When the deviation of the wind speed in the width direction is within the above range, the flow of the film-like molten resin extruded by the casting die is not disturbed, which is preferable. In the present invention, it is preferable that the heater 72 is disposed on the supply nozzle 70. The inert gas system sent to the supply nozzle 70 is heated to a predetermined temperature in advance, and then the supply nozzle 70 can be supplied from the supply pipe 73. However, the heater is disposed on the supply nozzle 70, and the supply of the lip from the front end of the supply nozzle 70 can be more stably suppressed. The temperature of the inert gas. Further, the gas which has been previously heated to a predetermined temperature may be heated again by the heater disposed in the nozzle. The heater 72 is preferably a rubber heater, a cartridge heater, an aluminum casting heater, or the like, but is not limited thereto. Particularly good is a cartridge heater. Further, the distance d from the surface of the film 1 of the molten resin extruded from the end portion of the supply nozzle 70 to the slit 3 2 is preferably 2 mm or more and 15 mm or less. When it is less than 2 mm, the film 10 may come into contact with the supply nozzle 70 due to the variation in the amount of the inert gas supplied to the nozzle 70 by -12-201043442. On the other hand, the air flow around the lip caused by the super inert gas easily changes, and the component adheres to the lips 33, 34 or adheres to the lip portion 33, and is oxidized and deteriorated to form aggregates. The distance between the front end portion of the suction nozzle 80 and the surface of the supply nozzle 70 10 is preferably 2 mm or more and 15 mm or less. The cooling step of the present invention, as shown in Fig. 1, is preferably performed by pressing the film-like resin on the first cooling roll 5. The contact roller 6 presses the resin on the first cooling roller 5 to form a film. Fig. 3 is an enlarged schematic cross-sectional view showing a state in which the molten film-like resin is pressed by the first contact roller 6. The surface of the touch roll 6 that is in contact with the first cooling roll 5 is cooled along the first cooling by the pressing force against the first cooling roll 5, and is narrowed (nip) with the first roll 5. After that, it is preferable that the contact roll 6 is pressed and the film thickness on the first cooling roll 5 is slightly uneven, which can be improved by smoothing. The following is an example of manufacturing a cellulose-based polymer film which is suitable for use in the present invention, and details the optical thin of the present invention. <Deuterated cellulose film> First, the constituent material of the cellulose-deposited film is described. [15 m m, the melted product of the sublimation property 34 is produced. Similarly, the film 3 is provided with the J-contact roll 6 to be passed down. A flat film having a higher flatness and a film which is elastic and which is deformed by the surface of the roll 5 to form a film of a molten resin of a narrow portion, and a method for producing a cycloolefin film - 13-201043442 (raw material resin) The cellulose of the cellulose raw material is not particularly limited, and for example, there is cotton velvet 'wood pulp or paper. The raw material cellulose thus obtained can be used in any ratio. The deuterated cellulose is preferably a deuterated cellulose having an ethyl fluorenyl group or a mercapto group having 3 to 2 carbon atoms. Examples of the fluorenyl group having 3 to 22 carbon atoms include propyl sulfonyl group (C2H5CO-), n-butyl fluorenyl group (C3H7CO-), isobutyl decyl group, amyl fluorenyl group (c4H9co -), isoprene group, second amyl group, The third pentamidine, octyl, decyl, octadecyl and oleyl. Preferred are a propyl group and a butyl group. The deuterated cellulose is preferably cellulose acetate, particularly preferably cellulose triacetate. When the mercapto group is an acid anhydride or an acid chloride, the organic solvent used as a reaction solvent is an organic acid (e.g., acetic acid) or dichloromethane. The deuterated cellulose preferably has a degree of substitution of hydroxy groups of cellulose of 2.6 to 3.0. The polymerization degree (viscosity average) of the deuterated cellulose is preferably from 200 to 700 Å and particularly preferably from 250 to 550. These deuterated celluloses are sold by Dicel Chemical Industries, COURTAULDS, Herst, and Isman Cotec. Preferably, photographic grades of deuterated cellulose are used. The water content of the deuterated cellulose is preferably 2% by mass or less. The glucose unit constituting the β-1,4 bond of cellulose has a free hydroxyl group at the 2nd, 3rd, and 6th positions. Deuterated cellulose is a polymer obtained by esterifying one or both of these hydroxyl groups with acetic acid or another acid. The thiol substitution degree indicates the ratio of cellulose esterification to the second, third, and sixth positions (100% esterification is !·〇〇). The thiol substitution degree of the second and third positions of the deuterated cellulose used is 14-201043442. The 素1 · 素 ( Ο 1 is more than the ethyl phenyl phenyl external combination) is 1.7 0 to 1.95. And the total substitution degree of the thiol group having the thiol group substitution degree of 0.88 or more and the thiol group of the 2nd position and the 3rd position is 70 to 1.95, and the thiol substitution degree of the 6th position is less than 0.88. The synthetic fiber is obtained by mixing. Next, the additive contained in the deuterated cellulose film will be described. Plasticizer) The plasticizer contained in the deuterated cellulose film is, for example, the following. The ester-based plasticizer composed of a polyhydric alcohol and a monocarboxylic acid, and an ester-based plasticizer composed of a polyvalent carboxylic acid and a polyhydric alcohol have a high affinity with a cellulose ester, which is preferable. The glycol ester-based plasticizer which is one of the polyol esters: specific examples thereof include an ethylene glycol alkyl ester plasticizer such as ethanol diacetate or ethylene glycol dibutylate, and a diol dicyclopropyl carboxylate. Ethylene glycol alkyl ester plasticizers such as ethylene glycol dicyclohexyl carboxylate, ethylene glycol benzoate, ethylene glycol dibenzoate, and ethylene glycol aryl ester plasticizers . These alkylate groups, cycloalkylate groups, and arylate groups may be the same or different and may be further substituted. Thus, it may also be a mixture of an alkylate group, a cycloalkylate group, an arylate group, or these substituents may be covalently bonded to each other. The ethylene glycol moiety may also be a partial structure of the ethylene glycol ester, which may be a part of the polymer, or a regular side chain, or may be introduced into a molecular structure of an additive such as an antioxidant, an acid scavenger, or an ultraviolet absorber. Part. A glyceride-based plasticizer which is one of polyhydric alcohol esters: specific examples include glycerin acetate, glyceryl tributyrate, diacetin octanoate, glycerin oil -15-201043442 acid ester propionate and the like Glyceryl aryl esters such as glycerol cycloalkyl esters such as glycerides, glycerol tricyclopropyl carboxylate and glycerol tricyclohexyl carboxylate; glycerol tribenzoate and glycerol-4-methyl benzoate; Diglyceryl alkyl esters such as glyceryl tetraacetate, diglycerin tetrapropionate, diglycerin acetate trioctanoate, diglycerin tetralaurate, diglycerol tetracyclobutyl carboxylate, diglycerol A diglycerin aryl ester such as a diglyceryl cycloalkyl ester such as a cyclopentyl carboxylate, a diglycerin tetrabenzoate or a diglycerin-3-methylbenzoate. These alkylate groups, cycloalkyl carboxylate groups, and aryl groups may be the same or different and may be further substituted. Further, it may be a mixture of an alkylate group, a cycloalkylcarboxylate group, an arylate group, or these substituents may be covalently bonded to each other. The glycerin and the diglycerin moiety may be substituted. The partial structure of the 'glyceride or the diglyceride may be a part of the polymer or may be a side chain regularly, or may be introduced into an antioxidant, an acid scavenger, an ultraviolet absorber, or the like. A part of the molecular structure of the additive. Other polyol ester-based plasticizers, for example, the polyol ester-based plasticizers described in paragraphs 30 to 33 of JP-A-2003-121823. These hospital base groups, cycloalkyl carboxylate groups, and aryl groups may be the same or different 'and may be substituted. It may be a mixture of an alkylate group, a cycloalkyl carboxylic acid aryl group, or an aryl group, or these substituents may be covalently bonded to each other. The polyol portion may be further substituted, and the partial structure of the polyol may be a part of the polymer, or may be a side chain regularly, or may be introduced into an additive such as an antioxidant, an acid scavenger, or an ultraviolet absorber. Part of the structure. -16- 201043442 The ester-based plasticizer formed by the above polyol and monocarboxylic acid is preferably an alkyl polyol aryl ester, and specifically, for example, the above-mentioned ethylene glycol dibenzoate or glycerol tribenzoic acid The ester compound, the diglycerin tetrabenzoate, and the exemplified compound 16 described in Paragraph 3 of JP-A-2000-128. A dicarboxylic acid ester plasticizer which is one of a polycarboxylic acid ester type: specifically, for example, dilauryl malonate (C1), dioctyl adipate (C4), dibutyl sebacate (C8) an alkyl dicarboxylate-based plasticizer, an alkyl dicarboxylic acid cycloalkyl ester plasticizer such as dicyclopentamyl succinate or dicyclohexyl adipate, diphenyl amber Alkyl dicarboxylate aryl esters such as acid esters of 'di-4-methylphenylglutarate, plasticizers, dihexyl-1,4-cyclohexanedicarboxylate, dimercaptobicyclo[2.2. 1] a cycloalkyldicarboxylic acid alkyl ester such as heptane-2,3-dicarboxylate, a plasticizer, dicyclohexyl-I,2-cyclobutanedicarboxylate, dicyclopropyl-I, Cycloalkyl dicarboxylic acid cycloalkyl ester plasticizer such as 2-cyclohexyl dicarboxylate, diphenyl-1,1-cyclopropyldicarboxylate, di-2-naphthyl-anthracene, 4_ Cycloalkyl dicarboxylate aryl esters such as cyclohexane dicarboxylate, plasticizer, diethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl benzene An aryl dicarboxylate alkyl ester such as a diester or a di-2-ethylhexyl phthalate, a plasticizer, cyclopropyl phthalate An aryl dicarboxylic acid cycloalkyl vinegar plasticizer such as dicyclohexyl phthalate, diphenyl phthalate, di-4-methylphenyl phthalic acid, aryl dicarboxylic acid aryl acetate The base vinegar is a plasticizer. These alkoxy groups and cycloalkoxy groups may be the same or different and may be monosubstituted, and these substituents may be further substituted. The h group or the cycloalkyl group may be mixed 'or these substituents may be covalently bonded to each other. The aromatic ring of the acid-acid can also be substituted, and can be a polymer such as a dimer, a trimer or a tetramer. The partial structure of the phthalate may be a part of the polymer from -17 to 201043442, or a side chain which is regularly formed into a polymer, and may also be introduced into an additive such as an antioxidant, an acid scavenger, or an ultraviolet absorber. Part of the structure. Other polycarboxylic acid ester-based plasticizers, for example, alkyl polycarboxylate alkyl esters such as trilauryl tricarboxylate, tributyl-meso-butane-1,2,3,4-tetracarboxylate Alkyl polycarboxylate cycloalkyl ester plasticizer such as plasticizer, tricyclohexyltricarboxylate, tricyclopropyl-2-hydroxy-1,2,3-propane tricarboxylate, triphenyl-2 An alkyl polycarboxylate aryl ester-based plasticizer such as -hydroxy-1,2,3-propane tricarboxylate, tetrakis-methylphenyltetrahydrofuran-2,3,4,5-tetracarboxylate, A cycloalkyl polycarboxylate alkyl ester such as tetrahexyl-1,2,3,4-cyclobutane tetracarboxylate, tetrabutyl-i, 2,3,4-cyclopentane tetracarboxylate Agent, tetracyclopropyl-1,2,3,4-cyclobutane tetracarboxylate, cycloalkylpolycarboxylic acid cycloalkyl ester such as tricyclohexyl-1,3,5-cyclohexyltricarboxylate a plasticizer, triphenyl-1,3,5-cyclohexyltricarboxylate, hexa-4-methylphenyl-1,2,3,4,5,6-cyclohexylhexacarboxylate Alkyl polycarboxylate aryl ester plasticizer, trilaurylbenzene-1,2,4-tricarboxylate, tetraoctylbenzene-1,2,4,5-tetracarboxylate, etc. Acid alkyl ester plasticizer, tricyclopentyl -1,3,5-tricarboxylate, tetracyclohexylbenzene-1,2,3,5-tetracarboxylate, aryl polycarboxylic acid cycloalkyl ester plasticizer, triphenylbenzene-1, An aryl polycarboxylate aryl ester plasticizer such as a 3,5-tetracarboxylic acid ester or a hexamethylphenylbenzene-1,2,3,4,5,6-hexacarboxylate. These alkoxy groups, cycloalkoxy groups may be the same or different, or may be monosubstituted, or these substituents may be further substituted. The alkyl group, the cycloalkyl group may be mixed, or these substituents may be covalently bonded to each other. The aromatic ring of phthalic acid may be further substituted, and may be a polymer such as a dimer, a trimer or a tetramer. The partial structure of the benzoic acid ester 18-201043442 may be a part of the polymer or a side chain of the polymer regularly, or may be introduced into the molecular structure of an additive such as an antioxidant, an acid scavenger, or an ultraviolet absorber. a part. The ester plasticizer composed of the above polyvalent carboxylic acid and monohydric alcohol is preferably a dialkyl carboxylic acid alkyl ester, and specific examples thereof include the above dioctyl adipate and • trilauryl tricarboxylate. Further, there are, for example, a phosphate-based plasticizer, a carbohydrate-based ester-based plasticizer, a polymer plasticizer, and the like. Phosphate-based plasticizers: specific examples thereof include alkyl phosphates such as triethylphosphonium phosphate and tributyl phosphate, cycloalkyl phosphates such as tricyclopentyl phosphate and cyclohexyl phosphate, and triphenyl phosphate. Cresyl phosphate, cresyl phenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, trinaphthyl phosphate An aryl phosphate such as ester, tris(dimethylphenyl) phosphate or cis-biphenyl phosphate. These substituents may be the same or different and may be substituted. 〇 may alternatively be a mixture of an alkyl group, a cycloalkyl group, an aryl group, or a substituent may be bonded to each other by a covalent bond. In addition, 'for example, ethyl bis(dimethyl phosphate), butyl bis(diethyl phosphate), etc. alkyl bis(dialkyl phosphate), ethyl bis(diphenyl phosphate) Ester), propyl bis(dinaphthyl phosphate), etc., bis (diaryl phosphate), phenyl bis (dibutyl phosphate), phenyl bis (dioctyl phosphate) An aryl bis(diaryl phosphate) such as aryl bis(dialkylphosphoric acid vinegar), phenyl bis(diphenyl phosphate), and naphthyl bis(xyl decyl orthoester) ) and other phosphate esters. These substitutions -19- 201043442 can be the same or different and can be replaced. It may be a mixture of an alkyl group, a cycloalkyl group, an aryl group, or a substituent may be covalently bonded to each other. The partial structure of the pity vinegar may be part of the polymer, or may be a regular side chain, or may be introduced into a part of the molecular structure of an additive such as an antioxidant, an acid scavenger, or an ultraviolet absorber. Among the above compounds, preferred are aryl aryl vinegar and aryl bis (diaryl phosphate), and specific examples thereof include triphenyl phosphate and phenyl bis(diphenyl phosphate). Next, a carbohydrate ester-based plasticizer will be described. Carbohydrate refers to a monosaccharide, disaccharide or trisaccharide in the form of a pyranose or furanose (6-membered ring or 5-membered ring). Non-limiting examples of the carbohydrate include, for example, glucose, sucrose, lactose, cellobiose, mannose, xylose, ribose, galactose, arabinose, fructose, sorbose, cellotriose, and raffinose. The carbohydrate hydrate refers to an aliphatic carboxylic acid ester or an aromatic carboxylic acid ester in which a hydroxyl group of a carbohydrate and a carboxylic acid are dehydrated and condensed to form an ester compound, more specifically, a carbohydrate. The aliphatic carboxylic acid may, for example, be acetic acid or propionic acid, and the aromatic carboxylic acid may, for example, be benzoic acid, tolyl acid or anisic acid. The carbohydrate compound has a number of hydroxyl groups in combination with the kind, but a part of the hydroxyl group can react with the carboxylic acid to form an ester compound, or all of the hydroxyl group can react with the carboxylic acid to form an ester compound. In the present invention, it is preferred that all of the 'hydroxyl groups are reacted with a carboxylic acid to form an ester compound. Carbohydrate ester plasticizer, specifically, for example, glucose pentaacetate, glucose pentapropionate 'glucose pentabutyrate, sucrose octaacetate, sucrose octabenzoate, etc., of which sucrose octaacetate is more preferred ester. Polymer plasticizer: specifically, for example, an aliphatic hydrocarbon polymer, an alicyclic hydrocarbon polymer, polyethyl acrylate, polymethyl methacrylate, methyl-20-201043442 methyl acrylate and methacrylic acid-2 a vinyl-based polymer such as a copolymer of hydroxyethyl ester (for example, an arbitrary ratio between a copolymerization ratio of 1:99 to 99:1), such as an acrylic polymer, polyvinyl isobutyl ether or poly N-vinylpyrrolidone Polystyrene polymer such as polymer, polystyrene or poly-4-hydroxystyrene, polybutylene succinate, polyethylene terephthalate, polyethylene naphthalate, etc. Polyether such as ethylene oxide or polypropylene oxide, polyamine, polyurethane, polyurea, and the like. The number average molecular weight is preferably 1, 〇〇〇~500, 〇〇〇0, and particularly preferably 5,000 to 200,000. When it is less than 1,000, the volatility may be problematic, and when it exceeds 500,000, the plasticizing ability is lowered, and the fiber is reduced. The mechanical properties of the ester film have an adverse effect. These polymer plasticizers may be a single polymer composed of one repeating unit or a copolymer having a plurality of repeating structures. Further, two or more kinds of the above polymers may be used. When the deuterated cellulose film of the present invention is colored, it has an influence on optical use. Therefore, the yellowness (yellow index, YI) is preferably 3.0 or less, more preferably 1. or less. The yellowness can be measured in accordance with J I S - K 7 1 0 3 . In the same manner as the cellulose ester, the plasticizer is preferably an impurity such as a residual acid, an inorganic salt or an organic low molecule which is generated during the production or storage, and more preferably has a purity of 99% or more. The residual acid and water are preferably 0.01 to 100 ppm, and the cellulose ester is melt-formed to suppress thermal deterioration, thereby improving film stability, optical properties of the film, and mechanical properties. '(Antioxidant) Cellulose ester promotes decomposition not only by heat but also by oxygen in a high-temperature environment such as melt film formation. Therefore, in the cellulose-degraded film of the present invention, it is preferred to use -21 - 0434442 as an antioxidant. Stabilizing agent. The antioxidant useful in the present invention is not limited to use as long as it is a compound capable of suppressing deterioration of the melt-molded material due to oxygen, and examples of useful antioxidants include phenolic compounds, hindered amine compounds, and phosphorus compounds. Further, a sulfur-based compound, a heat-resistant processing stabilizer, an oxygen sweeping agent, and the like are preferable, and among them, a phenol-based compound, a hindered amine-based compound, a phosphorus-based compound, and a lactone-based compound are particularly preferable. Hindered amine compounds (HALS) are described, for example, in columns 5 to 11 of the specification of U.S. Patent No. 4,6,9,9,5, and in columns 3 to 5 of the specification of U.S. Patent No. 4,839,405, preferably 2,2. , 6,6-tetraalkylpiperidine compounds, or their acid addition salts or their complexes with metal compounds. Commercial product is, for example, LA52 (made by Asahi Kasei Corporation). The lactone-based compound is preferably a compound described in JP-A-7-233 1 60 and JP-A-7-2472. These stabilizers can be used singly or in combination of two or more kinds, and the amount thereof can be appropriately selected within a range not affecting the object of the present invention, and is usually 0.001 to 10.0 parts by mass based on 100 parts by mass of the cellulose ester. Preferably, it is 1 to 5.0 parts by mass, more preferably 0.1 to 3.0 parts by mass. By adding these compounds, it is possible to prevent deterioration in coloring or strength of the molded article due to heat or thermal oxidative degradation during melt molding without lowering the state of transparency and heat resistance. The amount of the antioxidant added is usually 0.01 to 10 parts by mass, more preferably 5% to 5 parts by mass, more preferably 0 to 1 part by mass, per 100 parts by mass of the cellulose ester. -22- 201043442 (Acid scavenger) The acid scavenger is an agent that functions as an acid (protonic acid) that captures the residual ester in the ester which is introduced at the time of manufacture. Further, in the case of melting the fiber, hydrolysis of the side chain is promoted by moisture and heat in the polymer, and if it is, acetic acid or propionic acid is generated. As long as it can be chemically bonded to an acid, for example, a compound having an epoxy group, a tertiary amine, an ether structure or the like is not limited thereto. Specifically, it is preferably an epoxy compound containing an acid scavenger as described in U.S. Patent No. 4,1,37,20. Epoxy compounds as such removers are known in the art and include diglycidyl ethers of various diols, especially polyethylene glycol per 1 mole of time • 8 to 4 moles of epoxy B A metal epoxy compound (for example, a chlorinated polymer composition, and a chlorinated vinyl polymer composition have been utilized together with a diol or a glycidyl ether of a polyethylene glycol oil derived by condensation. , epoxidized ether condensation product, bisphenol A diglyceryl ether (ie, 4,4'-dihydroxydiphenyldimethylmethane), epoxy saturated fatty acid ester (especially 2 to 22 carbons) An alkyl ester of a carbon atom of an atomic fatty acid (for example, butyl epoxy stearic acid, etc.), and various epoxidized long-chain fatty acid triglycerides (for example, a composition such as oxidized soybean oil) Representative, for example, epoxidized vegetable oils and their 'saturated natural oils (sometimes referred to as epoxidized natural glycerides or fatty acids, which typically contain from 12 to 22 carbon atoms)). But the number says that the acid is clear, and the glycerin is shrinking. Not 2 esters), ring he does not and lipid-23- 201043442 (ultraviolet absorber) UV absorber, from the viewpoint of the prevention of ultraviolet light deterioration by a polarizer or a display device, the ultraviolet absorption energy of a wavelength of 370 nm or less It is excellent in terms of liquid crystal display, and it is preferable to absorb less visible light having a wavelength of 40 Onm or more. For example, there are salicylic acid-based ultraviolet absorbers (phenyl salicylate, p-tert-butylsalicylic acid vinegar, etc.) or benzophenone-based ultraviolet absorbers (2,4-dihydroxybenzophenone, 2 , 2'-dihydroxy-4,4,-dimethoxybenzophenone, etc.), benzotriazole-based ultraviolet absorber (2-(2,-hydroxy-3,-t-butyl- 5' -methylphenyl)-5-chlorobenzotriazole, 2-(2,-hydroxy-3,5,-di-t-butylphenyl)-5-chlorobenzotriazole, 2-( 2,-hydroxy-3,5,-di-t-pentylphenyl)benzotriazole, 2_(2,-hydroxy-3,-lauryl-5,-methylphenyl)benzotriazole '2-(2,-Hydroxy-3,-t-butyl-5,-(2-octyloxycarbonylethyl)-phenyl)-5-chlorobenzotriazole, (2,-hydroxy-3) ,-( 1_methyl-1-phenylethyl)-5,-(1,1,3,3,4-tetramethylbutyl)-phenyl)benzotriazole, 2- ( 2'- Hydroxy_3,,5,_di_(丨-methyl_丨_phenylethyl)_phenyl)benzotriazine, etc., cyanoacrylate UV absorber (2,_ethylhexyl- 2-cyano-3,3·diphenylacrylate, ethyl-2-cyano_3_ (3',4'-extension a dialkyl phenyl)-acrylate or the like, a triazine-based ultraviolet absorbing agent, or a compound described in JP-A-59-185, pp. A compound, an inorganic powder, or the like. The ultraviolet absorber is preferably a benzotriazole-based ultraviolet absorber or a triazine-based ultraviolet absorber having a high transparency and an effect of preventing deterioration of a polarizing plate or a liquid crystal element, and particularly preferably a spectroscopic absorption spectrum. A suitable benzotriazole-based UV absorber. Further, it is also possible to use a conventionally known ultraviolet absorbing polymer. The conventionally known ultraviolet absorbing polymer is not particularly limited, and examples thereof include a polymer obtained by separately polymerizing RUVA-93 (manufactured by Otsuka Chemical Co., Ltd.) and a polymer copolymerizing RUVA-93 with another monomer. Specifically, for example, PUVA-30M in which RUVA-93 and methyl methacrylate are copolymerized at a ratio of 3:7 (mass ratio), PUVA-50M copolymerized at a ratio of 5:5 (mass ratio), and the like are available. There is a polymer or the like described in JP-A-2003-113317. For commercial use, TINUVIN 109, TINUVIN 171, TINUVIN 3 60, TINUVIN 900, TINUVIN 928 (all manufactured by Ciba Japan Co., Ltd.), LA-31 (made by Asahi Kasei Co., Ltd.), and RUVA-100 (manufactured by Otsuka Chemical Co., Ltd.) can be used. Specific examples of the benzophenone compound are 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy- 5-sulfobenzophenone, bis(2-methoxy-4-hydroxy-5-benzimidylphenylmethane), and the like, but is not limited thereto. The addition of the ultraviolet absorber is preferably 0.1 to 20% by mass, more preferably 5% to 10% by mass, more preferably 1 to 5% by mass. These can be used in two or more types. (Viscosity reducing agent) A hydrogen bonding solvent can be added for the purpose of reducing the melt viscosity. Hydrogen Bonding-25- 201043442 Solvent refers to the electric negative atom (oxygen, nitrogen, etc.) as described by JN Israelachvili, "Intermolecular Forces and Surface Forces" (Kondo, Oshima, Hiroshi, published by McGraw-Hill, 1991). An organic solvent which generates a hydrogen atomic medium "bond" between a fluorine atom and a hydrogen atom which is covalently bonded to an electrically negative atom, that is, a bond force is large, and a bond containing hydrogen, for example, contains Ο-Η ( Oxygen-hydrogen bond), Ν-Η (nitrogen-hydrogen bond), FH (fluorine-hydrogen bond), and an organic solvent in which adjacent molecules are aligned with each other. These systems have the ability to form strong hydrogen bonds with cellulose compared to the intermolecular hydrogen bonds of cellulose resins, and the melt casting method performed by the present invention is separate from the cellulose resin used alone. The glass transition temperature can lower the melting temperature of the cellulose resin composition by adding a hydrogen bonding solvent, or lower the cellulose resin composition containing a hydrogen bonding solvent compared to the cellulose resin at the same melting temperature. Melt viscosity. Hydrogen-bonding solvents are, for example, alcohols such as methanol, ethanol, propanol, isopropanol, n-butanol, second butanol, third butanol, 2-ethylhexanol, heptanol, octanol, nonanol 'Dodecanol, ethylene glycol, propylene glycol, hexanediol, dipropylene glycol, polyethylene glycol, polypropylene glycol, methyl glycol butyl ether, ethyl glycol butyl ether, butyl glycol butyl ether , hexyl glycol butyl ether, glycerin, etc., ketones: for example, acetone, methyl ethyl ketone, etc., carboxylic acids: for example, formic acid, acetic acid, propionic acid, butyric acid, etc., ethers: for example, diethyl ether, tetrahydrofuran, dioxane, etc. And pyrrolidone: for example, N-methylpyrrolidone or the like, and an amine: for example, trimethylamine, pyridine, or the like. These hydrogen-bonding solvents may be used singly or in combination of two or more. Among them, alcohols, ketones and ethers are preferred, and methanol, ethanol 'propanol, isopropanol, octanol, dodecanol, ethylene glycol, glycerin, acetone, -26-201043442 tetrahydrofuran are preferred. More preferably, it is a water-soluble solvent such as methanol, ethanol, propanol, isopropanol, ethylene glycol, glycerin, acetone or tetrahydrofuran. The water solubility means that the solubility to water l〇〇g is 10 g or more. (retardation control agent) In the deuterated cellulose film, after forming an alignment film, a liquid crystal layer is provided, and the deuterated cellulose film and the retardation from the liquid crystal layer are combined to perform polarization compensation for optical compensation. Board processing. The compound to be added to control the retardation is an aromatic compound having two or more aromatic rings as described in the specification of European Patent No. 91,656A2, and can also be used as a retardation controlling agent. It is also possible to use two or more types of aromatic compounds. The aromatic ring of the aromatic compound may contain an aromatic heterocyclic ring in addition to the aromatic hydrocarbon ring. ' Particularly preferred is an aromatic heterocyclic ring, and the aromatic heterocyclic ring is generally an unsaturated heterocyclic ring. Among them, a compound having a 1,3,5-triazine ring is particularly preferred. 〇 (matting agent) The bismuth cellulose film may be added with fine particles such as a matting agent in order to impart smoothness, and the fine particles may be, for example, fine particles of an inorganic compound or fine particles of an organic compound. The matting agent is preferably as fine particles as possible, such as cerium oxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, clay, talc, calcined calcium citrate, water and calcium citrate, aluminum citrate, and citric acid. Inorganic fine particles such as magnesium or phosphoric acid calcium or crosslinked polymer fine particles. Among them, cerium oxide can reduce the smog of the film, so it is preferred. For example, the fine particles of cerium oxide are often surface-treated by organic matter, which reduces the smog of the film. Therefore, it is preferred that -27-201043442 preferably have organic substances such as halodecanes and alkoxy decanes. Alkane, oxime, etc. The larger the average particle diameter of the fine particles, the larger the smoothness effect, and conversely, the smaller the average particle diameter, the more excellent the transparency. Further, the average particle diameter of the secondary particles of the fine particles is in the range of 〇.〇5 to l.〇/zm. The average particle diameter of the secondary particles of the fine particles is preferably 5 to 5 nm, more preferably 7 to 14 nm. These fine particles are used in the deuterated cellulose film to produce irregularities on the surface of the cellulose film which are 〇.1~l.〇#m. The content of the microparticle-containing cellulose ester film is preferably from 0.05 to 0.3% by mass based on the cellulose ester. The fine particles of cerium oxide are, for example, AEROSIL 200, 200V, 300, R972, R 9 7 2 V, R 9 7 4, R 2 0 2 , R812, 0X50, TT600, etc., manufactured by AERO SIL Co., Ltd., Japan. For AEROSIL 200V, R972, R972V, R974, R202, R812. These fine particles may be used in combination of two or more kinds. When two or more types are used, they can be used in any ratio. At this time, fine particles having an average particle diameter or a different material such as AEROSIL 200V and R972V may be used in a mass ratio of 0.1:99.9 to 99.9:0.1. The presence of microparticles in the film used as the matting agent can also be used for other purposes to increase film strength. Further, it is known in the film that the presence of the above fine particles can also improve the alignment of the cellulose ester constituting the cellulose film of the present invention. (Polymer material) The cellulose film can be appropriately selected by mixing materials or oligomers other than cellulose esters. The polymer material or oligomer preferably has a compatibility with a cellulose ester. When the film is formed, the transmittance is 80% or more, more preferably 90% or more, and even more preferably 92% or more. At least one or more kinds of polymer materials or oligomers other than the cellulose 'ester are included in the package for the purpose of improving the viscosity control during heating and melting or the film properties after film processing. A film-forming apparatus by a melt casting method as shown in Fig. 1 is used to form a film of a bismuth cellulose film by adding various additives to the raw material resin of the fluorinated cellulose film as described above. (Extrusion step) Cellulose resin to be a raw material and other stability added when necessary

The additive such as a chemical agent is preferably mixed before being melted. For mixing, a V-type mixer, a conical spiral mixer, a horizontal roller mixer, etc.

General mixers such as Henshel mixers and ribbon mixers. The mixed 〇 film constituent material is melted at an extrusion temperature of 200 to 30 CTC using an extruder 1 and filtered by a leaf disc type filter 2 or the like to remove foreign matter. When the additives such as plasticizers are not pre-mixed, they can be mixed only in the middle of the extruder. For uniform addition, it is preferably extruded by the extruder 1 using a mixing device such as a static convergence machine 3, and the film constituent material filtered by the metal filter 2 is sent to the casting die 4, the self-casting die 4 The slit is extruded into a film shape. The casting die 4 is not particularly limited as long as it is used for producing a sheet or a film. The material of the casting die 4 is, for example, hard chrome, chromium carbide, chromium nitride, carbonized -29-201043442 titanium, titanium carbonitride, titanium nitride, super steel, ceramic (tungsten carbide, aluminum oxide, chromium oxide), etc. Solvent or plating, surface polishing, honing using #1000 or more honing stone, plane cutting with diamond honing stone #1000 or more (cutting direction is perpendicular to the resin flow direction) , electrolytic honing, electrolytic composite honing and other processors. The preferred material of the lip of the casting die 4 is the same as that of the casting die 4. Further, the surface accuracy of the lip portion is preferably 0.5 S or less, more preferably 0.2 S or less. The gap of the slit of the casting die 4 can be adjusted. Fig. 4 is a schematic view showing a casting die 4, Fig. 4(a) is a part of a side view, and Fig. 4(b) is a table τρ; a sectional view. Among the lips 33, 34 which form one of the slits 32 of the casting die 4, one is a lip 33 which is less rigid and deformable, and the other is a lip 34 which is fixed. Further, a plurality of heating bolts 35 are arranged at a certain pitch in the width direction of the casting die 4, that is, in the longitudinal direction of the slit 32. Each of the heating bolts 35 is provided with a block 36 having a buried electric heater 37 and a cooling medium passage, and each of the heating bolts 35 extends longitudinally through each of the blocks 36. The base of the heating bolt 35 is fixed to the die body 31, and the front end is coupled to the outer surface of the flexible lip 33. The block 36 is always air cooled, and at the same time, the input of the embedded electric heater 37 is increased or decreased, and the temperature of the block 36 is raised and lowered, whereby the heating bolt 35 is thermally expanded and contracted, and the position of the flexible lip 3 3 is changed to adjust the film. thickness of. A thickness gauge is set at a desired portion of the mold flow, whereby the thickness information of the detected web is fed back to the control device, and the thickness information is compared with the thickness information set by the control device, and the signal of the correction control amount from the same device is used. It can control the heating power or on rate of the heating bolt. The heating bolts 35 preferably have a length of 20 to 40 cm and a diameter of 7 to 14 mm, and -30 to 201043442, for example, a plurality of tens of heating bolts are preferably arranged at a pitch of 20 to 40 mm. Instead of the heating bolt 35, a gap adjusting member mainly composed of a bolt that manually moves back and forth in the axial direction to adjust the gap of the slit 32 may be provided. The gap of the slit 3 2 adjusted by the gap adjusting member is generally 500 to 1500 μm, preferably 800 to 1300 " m, more preferably 900 to 1200 〆 m. The optical film of the present invention is produced by providing a supply nozzle 70 for supplying an inert gas to the lip portion in the vicinity of the lip 3 3 and 34 of the casting die 4, and melting it from the slit 32 of the casting die 4. The resin is extruded, and a step of supplying an inert gas having a temperature of TC or higher and 300 ° C or lower to the lip portion by the supply nozzle 70 is omitted as described above in detail. (Cooling step) Flow from the extrusion step The film-like resin extruded by the die 4 is pressed by the first cooling roll 5 and the contact roll 6, and the surface is flattened when cooled. Fig. 5 shows an embodiment of the touch roll 6 (hereinafter, the contact roll A) As shown in the figure, the contact roller A is provided with an elastic roller 42 inside the flexible metal sleeve 41. The metal sleeve 41 is made of stainless steel having a thickness of 33 mm and has flexibility. When the sleeve 41 is too thin, the strength is insufficient. 'Inversely too thick, 'the elasticity is insufficient. It is understood that the thickness of the metal sleeve 41 is preferably 0.1 mm or more and 1. 5 mm or less. The elastic roller 42 is interposed between the bearings. The surface of the metal inner cylinder 43 that is freely rotatable is provided with a rubber 44 to form a drum shape. When the contact roller A is pressed against the first cooling roller 5, the elastic roller 42 presses the metal sleeve 41 against -31 - 201043442 on the first cooling roller 5, and the metal sleeve 41 and the elastic roller 42 are fitted to the first cooling roller. The shape of 5 is deformed to form a narrow nip with the first cooling roll. Inside the metal sleeve 41, a space formed between the elastic drum 42 and the elastic drum 42 flows therethrough. Fig. 6 and Fig. 7 show A contact roll b of another embodiment of the touch roll. Fig. 6 is a central cross-sectional view of a plane orthogonal to the axis of rotation, and Fig. 7 is a cross-sectional view of a plane including a rotating shaft. The contact roll B is flexible and seamless. The outer cylinder 51 made of a stainless steel pipe (for example, having a thickness of 4 mm) and the high-rigidity metal inner cylinder 5 2 having the same axial center inside the outer cylinder 5 1 are slightly formed. The outer cylinder 5 1 and the inner cylinder 5 2 are formed. The space 53 has a coolant 45. The contact rolls A and B are offset toward the first cooling roll by means of an offset means (not shown). The offset force of the offset means is F, and the film is divided by rolling.値F/W (linear pressure) along the width W of the first cooling roll 5 in the direction of the rotation axis is set to be 1 N/cm or more and 150 N/cm. In the state, a narrowing (nip) is formed between the contact rolls A, B and the first cooling roll 5, and the narrowing can correct the flatness when the film passes. Therefore, the contact roll is composed of a rigid body, as compared with the first 1 When the cooling rolls are not narrowed, the film is pressed for a long time with a small line pressure, so that the flatness can be corrected more surely. That is, when the line pressure is less than 1 N/cm, the parting line cannot be sufficiently eliminated. (The thickness of the longitudinal line is not uniform with the direction in which the film is conveyed.) Conversely, when the line pressure is more than 15 ON/cm, the film is not easily narrowed, and the film thickness is uneven in place of the film thickness. The surfaces of the contact rolls A, B are made of metal, and the surface of the contact rolls A, B can be made smoother than the case where the surface of the contact rolls is -32-201043442, so that a film having high smoothness can be obtained. The material of the elastic body 44 of the elastic roller 4 2 may be ethylene propylene rubber, neoprene rubber, enamel rubber or the like. In order to smoothly remove the mold line by the touch roll 6, the film viscosity at the time of the contact roll 6 rolling the film becomes important within an appropriate range. Also, cellulose resin • It is known that the viscosity changes due to temperature. Therefore, when the viscosity at the time of pressing the cellulose film by the contact roll 6 is set to an appropriate range, it is important to set the temperature of the film when the film is contacted with the 0 roll 6 to an appropriate range. When the glass transition temperature of the deuterated cellulose film is Tg, the film temperature T before the film is pressed by the contact roll 6 is set to satisfy Tg + 80 ° C < T < Tg + 140 ° C. When the film temperature T is lower than Tg, the viscosity of the film is too high. Conversely, when the temperature τ of the film is higher than T g + 1 40 °c ', the film surface and the roller cannot be uniformly followed, and the mold line cannot be corrected. It is preferably Tg + iocrccTsTg + isiTc, more preferably Tg + iiot: < T < Tg + 130 °C. When the film temperature at which the contact roll 6 is pressed to press the film is set to a suitable range, only the melt which is obtained by the casting die 4 is adjusted to be in contact with the first cooling roll 5 at the position P1 along with the first cooling roll. The length L of the first cooling roller 5 which is narrowed by the contact roller 6 may be the length L in the rotation direction. Preferred materials for the first cooling roll 5 and the second cooling roll 6 are, for example, carbon steel, stainless steel, resin, or the like. Further, the surface precision is improved, and the surface roughness is 0.3 S or less, and more preferably 〇 ols or less. The film-form cellulose ester-based resin in a molten state is sequentially adhered to the first roll (first cooling roll) 5, the second cooling roll 7, and the third cooling roll 8 by the casting die 4, and is simultaneously cooled. Curing to obtain an unstretched cellulose ester-33-201043442 resin film 1 〇. (Peeling Step) The peeling step is a step of peeling off the cooled and solidified film 1 from the third cooling roll 8 by the peeling roller 9. (Extension Step) After the peeling, the cooled and solidified unstretched film 10 is passed through a dancer roll (film tension adjusting roll) 1 1 and then introduced into a longitudinal stretching machine 1 2a, where it is longitudinally stretched. Next, the horizontal stretcher 1 2b is introduced, and the film 10 is stretched in the lateral direction (wide direction). Thereby extending, the molecules in the film are aligned. The method of longitudinally stretching the film is preferably a method of stretching by a difference in speed between two rolls. The method of extending the film in the width direction is preferably controlled by using a known tenter or the like. The glass transition temperature Tg of the film constituent material can be controlled by different ratios of the material types and constituent materials constituting the film. When a retardation film as an optical film is produced, the Tg is 1201 or more, preferably 135. (: Above. In the display state of the liquid crystal display device image, the temperature of the device itself rises. For example, the temperature rise from the light source changes the temperature environment of the film. At this time, when the Tg of the film is lower than the ambient temperature of the film, The elongation from the alignment state of the molecules fixed in the inside of the film and the size and shape of the film are greatly changed by stretching. When the Tg of the film is too high, the temperature at which the film constituent material is formed into a film is increased, and thus heating is performed. The energy consumption is increased from -34 to 201043442, and the material itself is decomposed and colored when thinned. Therefore, Tg is preferably 250 ° C or less. Further, in the extending step, cooling can be performed by well-known heat-fixing conditions. And the treatment, and the characteristics required for the objective optical film can be appropriately adjusted. • In order to impart the physical properties of the phase film and the function of the phase film for expanding the viewing angle of the liquid crystal display device, the above-mentioned extension step and heat fixation treatment can be performed. Suitable for 0. When such an extension step and heat setting treatment are included, the heating and pressurizing step of the present invention is based on The step of stretching and the step of forming the retardation film as the optical film before the heat-fixing treatment are further required to have the function of the polarizing plate protective film, and the refractive index control must be performed, but the folding rate control can be performed by the stretching operation. And the extending operation is a preferred method. The stretching method will be described below. In the step of extending the retardation film, 1.01 to 2.0 times of the Q direction of the cellulose resin is extended, and 1.01 is performed in the direction perpendicular to the film. - 2.5 times extension, which can control the necessary delays Ro and Rt, where Ro is the in-plane retardation, the difference between the refractive index of the MD in the length direction of the in-plane and the refractive index of the width direction TD is multiplied by the thickness, and Rt is the thickness direction. The retardation, the difference between the in-plane refractive index (the average of the longitudinal direction MD and the width direction TD) and the refractive index in the thickness direction is multiplied by the thickness. The extension is, for example, the longitudinal direction of the film and the direction orthogonal to the film surface. , that is, the width direction, can be extended sequentially or simultaneously. At this time, if the stretching ratio of at least one direction is too small, a sufficient phase difference cannot be obtained, -35-20 1043442 When it is too large, it is difficult to extend the film. Sometimes the film is broken in two directions. It is an effective method to set the refractive index ηχ, ny, and nz of the film to a predetermined range. The nX system represents the length MD. The refractive index of the direction 'ny' indicates the refractive index in the width td direction, and nz indicates the refractive index in the thickness direction. For example, when extending in the direction of the melt casting, when the shrinkage in the width direction is too large, the nz値 is too large. It can be improved when it is wide-shrinked or extended in the width direction. When extending in the width direction, a refractive index distribution sometimes occurs in the width direction. This distribution sometimes occurs when the tenter method is used, and the film is extended in the width direction. A phenomenon in which a contraction force is generated at a central portion of the film and the end portion is fixed, that is, a so-called bowing phenomenon. At this time, it is also possible to extend in the casting direction, thereby suppressing the bending phenomenon and reducing the phase difference distribution in the width direction. By extending in the two-axis direction orthogonal to each other, the film thickness variation of the obtained film can be reduced. When the film thickness of the retardation film is excessively large, the phase difference is uneven, and when it is used for a liquid crystal display, there is a problem that unevenness in coloring or the like occurs. The film thickness variation of the cellulose resin film is preferably ± 3%, more preferably ± 1%. (Winding step) After the stretching step, the end portion of the film is cut into a width of the product by the cutter 13 to be cut, and the embossing ring 14 and the back roller 15 are used to form a burr processing device. Embossing processing is performed on both ends of the film. Then, by winding the winding machine -36-201043442 of the winding step, a deuterated cellulose film (original roll) F was obtained. The embossing process can be processed by heating or pressurizing a metal ring having a convex-concave pattern on the side. The grip portion of the jig at both ends of the film is usually deformed and cannot be used as a film product, so it is reused as a raw material after being cut. <Cycloolefin polymer film> First, the constituent material of the cycloolefin polymer film will be described.环 The cycloolefin polymer used in the present invention is composed of a polymer resin containing an alicyclic structure. Preferably, the cyclic olefin polymer-based cyclic olefin is polymerized or copolymerized. The cyclic olefin is, for example, norbornene, dicyclopentadiene, tetracyclododecene, ethyltetracyclododecene, ethylene tetracyclododecene, tetracyclo[ 7.4.0·110,13·〇 2,7] 13-2,4,6,11-tetraene and other polycyclic structures of unsaturated hydrocarbons and derivatives thereof; cyclobutene, cyclopentene, cyclohexene, 3,4-dimethyl ring Pentene, 3-methylcyclohexene, 2-(2-methylbutyl)-l-cyclohexene, cyclooctene, 3&, 5,6,7&-tetrahydro-4,7- An unsaturated hydrocarbon having a monocyclic structure such as methyl-111-oxime, cycloheptene, cyclopentadiene or cyclohexadiene, and derivatives thereof. These cyclic olefins may have a polar group as a substituent. The polar group is, for example, a trans group, a carboxyl group, an alkoxy group, an epoxy group, a epoxypropyl group, an oxycarbonyl group, a aryl group, an 'amino group, an ester group, a carboxylic anhydride group, etc., and is particularly preferably an ester group, a carboxyl group or Anhydride group. A preferred cycloolefin polymer may be one in which a monomer other than a cyclic olefin is subjected to addition copolymerization. The addition-polymerizable monomer may, for example, be ethylene, propylene, 1-butene or 1-pentene, such as ethylene or hydrazine: olefin; 1,4-hexadiene, 4-methyl-37-201043442- Anthracene cyclic olefin such as 1,4-hexadiene, 5-methyl-1,4-hexadiene or 1,7-octadiene may be subjected to addition polymerization or metathesis ring-opening polymerization. Got it. The polymerization is carried out in the presence of a catalyst. The catalyst for addition polymerization is, for example, a polymerization catalyst composed of a vanadium compound and an organoaluminum compound. The catalyst for ring-opening polymerization is, for example, a polymerization catalyst composed of a metal halide such as ruthenium, rhodium, palladium, starvation, ruthenium or platinum, a nitrate or an acetonyl acetonate compound and a reductant: or titanium, vanadium, zirconium or tungsten A metal halide such as molybdenum or a polymerization catalyst composed of an acetyl acetonide compound and an organoaluminum compound. The polymerization temperature, pressure, and the like are not particularly limited, and polymerization is generally carried out at a polymerization temperature of -50 ° C to 100 ° C and a polymerization pressure of 0 to 490 N / cm 2 . The cycloolefin polymer used in the present invention is preferably obtained by subjecting a cyclic olefin to polymerization or copolymerization and then hydrogenating the unsaturated bond in the molecule to become a saturated bond. The hydrogenation reaction is carried out by blowing hydrogen gas in the presence of a known hydrogenation catalyst. Hydrogenation catalysts are, for example, cobalt acetate/triethylaluminum, nickel acetonylacetone/triisobutylaluminum, dicyclopentadienyl dichloride/n-butyllithium, dicyclopentadienyl dichromate/ Uniform system catalyst composed of a combination of a transition metal compound/alkyl metal compound such as a second butyl lithium 'tetrabutoxy titanate / dimethyl magnesium; an uneven metal contact of nickel, palladium 'platinum or the like Medium; nickel/cerium oxide, nickel/diatomite, nickel/alumina 'palladium/carbon, palladium/cerium oxide, palladium/diatomite, palladium/alumina metal catalyst supported on the support The resulting heterogeneous solid is supported by a catalyst or the like. The cycloolefin polymer is, for example, the following norbornene-based polymer. The norbornene-based polymer preferably has a norbornene skeleton as a repeating unit, and a specific example thereof is disclosed in Japanese Laid-Open Patent Publication No. SHO-62-250 Japanese Unexamined Patent Publication No. Hei No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. Japanese Unexamined Patent Publication No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. No. Hei. It is preferable that it is described in Japanese Laid-Open Patent Publication No. Hei 7-62-02 No. Hei. Further, these may be used alone or in combination of two or more. In the present invention, the norbornene-based polymer preferably has a repeating unit represented by any one of the following structural formulae (I) to (IV). [Chemical 1]

-39- 201043442 In the above structural formulae (I) to (IV), each of A, B, c and D independently represents a hydrogen atom or a monovalent organic group. Further, among the carbon-lowering polymers, polymerization of at least one of the compounds represented by the following structural formula (V) or (VI) and meta-polymerization of the unsaturated cyclic compound copolymerizable therewith is preferred. The hydrogenated polymer obtained by hydrogenation. [Chemical 2] "cm:

D In the above structural formula, each of A, B, C and D independently represents a hydrogen atom or a monovalent organic group. Here, the above A, B, C and D are not particularly limited, and are preferably a hydrogen atom, a halogen atom, a monovalent organic group, or an organic group which may be bonded to at least a divalent linking group, and these may be the same or different. Also, A or B and C or D may form a monocyclic or polycyclic structure. The above-mentioned at least two-valent linking group means a hetero atom represented by an oxygen atom, a sulfur atom or a nitrogen atom, and examples thereof include an ether, an ester, a carbonyl group, a urethane, a decylamine, a thioether, and the like, but are not limited thereto. Further, the organic group may be further substituted in the above-mentioned linking group. Further, other monomers copolymerizable with the norbornene-based monomer, such as ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1- Decadiene, 1-tetradecene, :!-hexadecene, octadecene, and octadecene, etc., such as a 2-olefin having 2 to 2 carbon atoms, and derivatives thereof; cyclobutene and cyclopentane Alkene-40- 201043442, cyclohexane, cyclooctane, 3a,5,6,7a-tetrahydro-4,7-methyl-1H- isomer, and their derivatives; 1,4- A non-conjugated diene such as hexadiene, 4-methyl-1,4-hexanediazine, 5-methyl-1,4-hexadiene or 1,7-octadiene. Among these, α-canthene is preferred, and ethylene is particularly preferred. These other monomers which can be copolymerized with the norbornene-based monomer can be used alone or in combination of two or more. When the decene-based monomer is subjected to addition copolymerization with other monomers copolymerizable therewith, the structural unit derived from the decene-based monomer in the addition copolymer and the structure derived from other monomers copolymerizable The ratio of the unit, expressed as a mass ratio, may be appropriately selected to be 30: 70 to 99: 1, preferably 5 0: 50 to 97: 3, more preferably 70: 30 to 95: the range of 5 will remain in the synthesis. When the unsaturated bond in the molecular chain of the polymer is saturated by a hydrogenation reaction, the hydrogenation rate is 90% or more, preferably 95% or more, and particularly preferably 99% from the viewpoints of light resistance deterioration, weather resistance deterioration, and the like. the above. Further, the cycloolefin polymer which can be used in the present invention is, for example, a thermoplastic saturated decene-based resin described in paragraphs [0014] to [0019] of JP-A-5-2108, and JP-A-200-277430 [0015] The thermoplastic norbornene-based polymer described in [0031], and the thermoplastic norbornene-based resin described in paragraphs [0008] to [0045] of JP-A-2003-1 490, JP-A-2003- 1 39950 The norbornene-based resin composition described in paragraphs [0014] to [0028], and the norbornene-based resin and the special opening 2 described in paragraphs [0029] to [0037] of JP-A-2003-166 005 - 1 95268, paragraph [〇〇27]~[〇03 6], the decene-based resin, and the paragraph [0009]~[0〇23] of the Japanese Patent Publication No. 2003-2 1 589 contain an alicyclic group. -41 - 201043442 Polymer Resin, JP-A-2003-201 1 1 5 88 [0008] [0024] The decene-based polymer resin or the vinyl alicyclic hydrocarbon polymer resin described in detail In other words, it is preferable to use AΖΕΟΝ (ΖΕΟΝΟΑ), J, JSR (share) ARTON, Mitsui Chemical (share) APL (APL8008T, AP) L6509T, APL6013T, APL5014DP, APL6015Τ), etc. The molecular weight of the cycloolefin polymer used in the present invention can be appropriately selected depending on the purpose of use, but the polyisoprene is determined by gel permeation chromatography using a cyclohexane solution (a toluene solution when the polymer resin is not dissolved). When the weight average molecular weight converted from polystyrene is generally from 5,000 to 500,000, preferably from 8,000 to 200,000, more preferably from 10,000 to 100,000, the mechanical strength and the formability of the formed body are highly balanced, so that it is preferred. . When a low volatility antioxidant in a ratio of 0.01 to 5 parts by mass is blended with respect to 100 parts by mass of the cycloolefin polymer, decomposition or coloring of the polymer during the molding process can be effectively prevented. In order to improve the film properties, the cycloolefin polymer film may contain various additives similarly to the bismuth cellulose film. The method for producing a cycloolefin polymer film using the constituent material of the cycloolefin polymer film is the same as that of the deuterated cellulose film, and therefore, a description thereof will be omitted. As described above, by using the method for producing an optical film of the present invention, it is possible to produce the lip portions 33 and 34 of the casting die 4 without adhering to the aggregate, and no foreign matter is mixed into the film, and there is no line in the direction in which the film is conveyed. Uneven film thickness -42 - 201043442 film. In particular, the cellulose-deposited cellulose film as the optical film of the present invention can produce a foreign matter which is not reflected by white light due to irradiation of light, and does not cause reflection on the film surface due to uneven film thickness of the film. High quality film of light waves. Therefore, the optical film of the present invention is used as a polarizing plate as a protective film for a polarizing plate, and a liquid crystal display device having high display quality can be obtained. • The optical film 0 manufactured by the method for producing an optical film of the present invention can be used for a liquid crystal display device. Various display devices such as a plasma display device and an organic EL display device can be used as an optical compensation film such as a phase difference film, an antireflection film, a brightness enhancement film, and a viewing angle expansion, in addition to the protective film for the polarizing plate. Next, a "polarizing plate" and a liquid crystal display device using the same using the optical film of the present invention as a protective film will be described. (Polarizing Plate) 时 When the optical film of the present invention is used as a protective film for a polarizing plate, a polarizing plate is produced by a general method. It is preferable that the optical film of the present invention has an adhesive layer on the back side thereof and is attached to at least one surface of the polarizing mirror which is formed by immersion in an iodine solution. The optical film of the present invention can also be used on the other side, and other polarizing plates can be used to protect the film. It is preferred to use, for example, a commercially available cellulose ester film (for example, Konicaminoltatac KC8UX, KC4UX, KC5UX, KC8UY, KC4UY, KC12UR, KC8UCR-3, KC8UCR-4, KC8UCR-5, KC8UE, KC4UE, KC4FR-3, KC4FR- 4, -43- 201043442 KC4HR-1 'KC8UY-HA 'KC8UX-RHA, the above is Konicaopto (share) system) and so on. The polarizer of the main constituent elements of the polarizing plate refers to an element that passes only the light of the deflecting surface in a certain direction. The representative polarizing film currently known is a polyvinyl alcohol-based polarizing film, and these have iodine for the polyvinyl alcohol-based film. Dyers and those who perform dichroic dye staining. The polarizer may be obtained by forming a film of a polyvinyl alcohol aqueous solution, uniaxially stretching it, or dyeing it, and then performing uniaxial stretching, preferably by durability with a boron compound. Preferably, the adhesive used in the adhesive layer is an adhesive having a storage elastic modulus of at least 5 5 ° C and a range of 1.0 x 10 Pa to 1.0 x 109 Pa at at least a portion of the adhesive layer, and is also suitable for use as a coating adhesive. After bonding, a hardening type adhesive which forms a local molecular weight body or a crosslinked structure by various chemical reactions. Specific examples thereof include a urethane-based pressure-sensitive adhesive, an epoxy-based pressure-sensitive adhesive, a water-based polymer-isocyanate-based pressure-sensitive adhesive, a thermosetting acrylic adhesive, and the like, and a moisture-curing urethane adhesive. , polyether methacrylate type, ester type methacrylate type oxidized polyether methacrylate and other anaerobic adhesives, cyanoacrylate type instant adhesives, acrylates and peroxides The second liquid type instant adhesive and the like. The above-mentioned adhesive may be a one-liquid type or a liquid type in which two or more liquids are mixed before use. Further, the above-mentioned adhesive may be a solvent type based on an organic solvent or a solvent containing a water-based medium, a colloidal dispersion type, an aqueous solution type, or the like, or a solvent-free type. The concentration of the above-mentioned adhesive liquid may be appropriately determined by the film thickness after the adhesion, the coating method, the coating conditions, and the like, and is usually 0.1 to 50% by mass. (Liquid Crystal Display Device) The liquid crystal display device can be fabricated by assembling a polarizing plate to which the optical film of the present invention is bonded to a liquid crystal display device. In particular, it can be used for outdoor applications such as large liquid crystal display devices or digital signs. Liquid crystal display device. The polarizing plate of the present invention is bonded to a liquid crystal cell in the above-mentioned adhesive layer or the like. The polarizing plate of the present invention is suitable for a reflective type, transmissive type, semi-transmissive type.

Various drive modes such as Lc〇 or TN type, STN type, OCB type, HAN type, VA type (PVA type, MVA type), IPS type (including FFS type). EXAMPLES Hereinafter, the present invention will be specifically described by way of Examples, but the present invention is not limited thereto (Examples 1 to 6, Comparative Examples 1 and 2) (manufactured by granules) 100 parts by mass of cellulose acetate propionate (Substitution degree of ethyl ketone group 1.95, degree of substitution of propyl fluorenyl group 〇.7, number -45- 201043442 average molecular weight 75 000, drying at 130 ° C for 5 hours, glass transition temperature Tg = 174 ° C) Propane tris(3,4,5-trimethoxybenzoate) 1 〇 parts by mass IRGANOX-1010 (manufactured by CIBA-JAPAN Co., Ltd.) 1 part by mass

Sumilizer GP (manufactured by Sumitomo Chemical Co., Ltd.) 0.05 parts by mass of a oxidizing agent-containing cerium oxide particle (AEROSIL R972V (manufactured by AEROSIL Co., Ltd.)) and 0.5 parts by mass of a UV absorber TINUVIN3 60 (manufactured by CIBA·JAPAN Co., Ltd.) After mixing for 30 minutes with a V-type mixer sealed with a nitrogen gas, a 2-axis extruder (manufactured by PCM30 Co., Ltd.) equipped with a stranding die was used to melt and produce a length of 4 mm and a diameter at 240 ° C. 3mm roll-shaped particles. The cutting speed is now set to 25 ( /s). (Production of Film) The film was produced by the manufacturing apparatus shown in Fig. 1. The pellets after the production (water content: 5 〇 PPm) were melted in a 1-axis extruder, and subjected to pressure filtration using a Leaf Discs type metal damper. A cast film having a film thickness of 1 00 " m was obtained by a casting die at a melting temperature of 2500 ° C in a film-like melt-squeezing at a surface temperature of 1 00 ° C on the first cooling light. At this time, the gap of the slit 32 of the casting die 4 was 1.0 mm, and the average surface roughness Ra of the lips 33 and 34 was O.Olym. Further, from the hopper opening of the intermediate portion of the extruder 1, 0. 1 part by mass of -46 to 201043442 of cerium oxide fine particles as a lubricant was added. The supply of the inert gas to the lip by the supply nozzle 7 is the use of the apparatus of Fig. 2, and the gas is a nitrogen gas. The gap d between the end portion of the supply nozzle 70 and the film was 5 mm, and the nitrogen gas having the temperature shown in Table 1 was heated by the cartridge heater 72 to be ejected from the front end portion of the supply nozzle 70. Further, the nitrogen gas was ejected from the front end portion of the supply nozzle 70 at the wind speed shown in Table 1 by adjustment valve adjustment (not shown). 0 The suction nozzle 80 is disposed with a gap of 5 mm between the tip end portion and the film, and the suction force at the end portion before the suction nozzle 80 is adjusted by a regulating valve (not shown) so that the wind speed and the wind speed at the front end of the nozzle 70 are supplied. The same to attract. The first cooling roll and the second cooling roll were made of carbon steel having a diameter of 40 cm, and the surface of the watch was hard chrome plated. Further, the oil for temperature adjustment (cooling fluid) is circulated internally to control the surface temperature of the roll. The elastic contact roller has a diameter of 3 5 cm, the inner cylinder and the outer cylinder are made of carbon steel, and the outer cylinder surface is plated with hard chrome. The wall of the outer cylinder is 2 mm thick, and the oil for temperature adjustment (fluid for cooling) circulates in the space between the inner cylinder and the outer cylinder to control the surface temperature of the elastic contact roller. Further, the film on the first cooling roll 5 is pressed by the contact roller B shown in Figs. The outer cylinder 51 of the contact roller B was extruded using a 2 mm thick carbon steel pipe at a linear pressure of 5 N/cm. The temperature of the film on the side of the contact roll B at the time of extrusion is 245 ° C ± 1 ° C (here, the temperature of the film on the side of the contact roll B at the time of extrusion is contacted by the contact roll B on the first cooling roll 5). The film temperature at the position uses a non-contact thermometer to make the contact roller B retreat, and in the state without the contact roller B, the average surface temperature of the film is measured at a temperature of 1 〇 from the position of 50 cm in the width direction - 47 - 201043442) . The film had a glass transition temperature Tg of 136 ° C (manufactured by SEIKO Co., Ltd., DSC 6200, and the glass transition temperature of the film extruded by the die was measured by the DSC method (nitrogen, heating temperature 1 〇 ° C / min)). The surface temperature of the touch roll B was 100 ° C, and the surface temperature of the second cooling roll 7 was 80 ° C. The surface temperature of each of the contact roller B, the first cooling roller 5, and the second cooling roller 7 is the position at which the film first contacts the roller, and the surface temperature of the roller at the front position of 90° with respect to the rotational direction is a wide non-contact thermometer. Directional measurement 1 The average enthalpy of enthalpy is used as the surface temperature of each roller. The film forming speed was 20 m/min. The obtained film was introduced into a tenter of an extension device, stretched 1.3 times in the width direction at 16 ° C, and wound into a roll to form an optical film. (Evaluation) The optical film was continuously produced by the manufacturing apparatus of Fig. 1 to visually observe the interference of the longitudinal lines on the surface of the film before the winding step, until the continuous film formation time until the occurrence of interference was observed. When the evaluation level is more than 400 hours, it is evaluated as ◎, and it is more than 50 hours, and if it is less than 40 hours, it is evaluated as 〇', and when it is 50 hours or less, it is evaluated as X. When the temperature is below 50 hours, the device must be frequently stopped to clean the lip of the casting die, and the productivity is greatly lowered, which may cause problems as a manufacturing device. The evaluation results are shown in Table 1. -48 - 201043442

[Table i] Gas temperature V Gas wind speed m/s Evaluation result Example 1 110 1 ◎ Example 2 300 1 ◎ Example 3 200 0.2 〇 Example 4 200 0.3 ◎ Example 5 200 3 ◎ Example 6 200 3.2 〇Comparative Example 1 100 1 X Comparative Example 2 310 1 X Ο From the results of Table 1, it is understood that an inert gas having a temperature of 1 〇 ° C or more and 300 Torr or less is supplied from a supply nozzle to the lip of the casting die. Long-term line-like interference on the surface of the film does not occur for a long time. In Comparative Examples 3 to 6, it was found that the gas wind speed was preferably 0.3 m/s or more and 3 m/s or less. (Example 7) 实施 In the production of the optical film of Example 4, an optical film was produced in the same manner as in Example 4 except that the contact roll B was not used. The evaluation result was rated as ◦, and the time of occurrence of vertical line interference was shorter than that of Example 4. From this, it is understood that the use of the contact roller is less likely to cause longitudinal line-like interference, which is preferable. (production of polarizer)

The long-rolling polyvinyl alcohol film having a thickness of 1 2 0 // m is immersed in 100 parts by mass of an aqueous solution containing 1 part by mass of iodine and 4 parts by mass of boric acid, and 6 times in the direction of transport at 50 ° C -49 - 201043442 Extend the polarizer. The alkali saponified surface of the deuterated cellulose film produced in Example 1 was used as a polarizer side, and a completely saponified polyvinyl alcohol 5 mass% aqueous solution was used as a binder, and both surfaces were bonded to the rain side of the polarizer to prepare a sticker. A polarizing plate incorporating a protective film for a polarizing plate. <<Evaluation of Characteristics of Liquid Crystal Display Device>> A polarizing plate of a 32-type TFT type color liquid crystal display Vega (manufactured by Sony Corporation) was peeled off. Each of the polarizing plates produced above was cut to match the size of the liquid crystal cell. The 32-type TFT type color liquid crystal display was fabricated by sandwiching the liquid crystal cell in such a manner that the polarizing axis of the polarizing plate was the same as that of the original polarizing plate, and the polarizing plate was prepared in a straight manner. As a result of the characteristics of the polarizing plate of the film, as a result, the polarizing plate produced by the cellulose film of the optical film of the present invention exhibits excellent unevenness in color of the wireless strip or image deformation. In this way, it is confirmed that the polarizing plate used as the image display device is extremely excellent. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic flow chart showing the overall configuration of a device for carrying out the method for producing an optical film of the present invention. [Fig. 2] is a schematic cross-sectional view of the periphery of the lip of the casting die. Fig. 3 is a schematic cross-sectional view showing a state in which a molten film-like resin is pressed by a cooling roll and a contact roll. [Fig. 4] A part of the side view of the casting die 4 and a section of the profile - 50 - 201043442 Fig. 5 is a schematic cross-sectional view of one embodiment of the contact roller [Fig. 6] A central cross-sectional view of a plane orthogonal to the axis of rotation of the embodiment. Fig. 7 is a cross-sectional view showing a plane including a rotating shaft of another embodiment of the touch roll. ❹ Ο [Explanation of main components] 1 : Extruder 2 : Filter 3 : Static mixer 4 : Casting die 6 7 5 : First cooling roller contact car 2nd cooling roller 3rd cooling roller peeling roller 1 : 1 3, 1 4, 1 5 : conveying roller 12a : longitudinal stretching device 12 b : lateral stretching device 10 : film 1 6 : winding device 3 2 : slit 3 3, 34: lip - 51 - 201043442 41 : metal Sleeve 42: elastic roller 43: metal inner cylinder 44: rubber 4 5: cooling liquid 5 1 : outer cylinder 52: inner cylinder 53: space 70: supply nozzle 7 1 , 8 1 : nozzle side plate 7 2 : heater 73: supply pipe 82: discharge pipe

Claims (1)

201043442 VII. Patent application scope: 1. A method for producing an optical film, comprising: an extrusion step of extruding a molten resin from a lip of a casting die into a film shape, and extruding the extrusion step The method for producing an optical film of a film-form resin by a cooling step of cooling and solidifying by a cooling roll, characterized in that the extrusion step is to supply an inert gas having a temperature of 1 〇 ° C or more and 300 ° C or less from a supply nozzle. The aforementioned lip. The method for producing an optical film according to claim 1, wherein the step of supplying the inert gas is performed by the front end of the supply nozzle, and the wind speed of the inert gas is 0.3 m/s or more and 3 m/s or less. . 3. The method for producing an optical film according to claim 1 or 2, wherein the supply nozzle is provided with a heater, and the inert gas is heated. &lt; 〇 4. As in any one of claims 1 to 3 In the method of producing an optical film, the suction nozzle is disposed on the downstream side in the direction in which the film-like resin flowing out of the supply nozzle is drawn, and the suction nozzle sucks the inert gas discharged from the supply nozzle. 5. The method of producing an optical film according to any one of claims 1 to 4, wherein the inert gas is a nitrogen gas. 6. The method of producing an optical film according to any one of claims 1 to 5, wherein the cooling step is provided with a contact roll for pressing a film-like resin on the cooling roll, and is pressed by the contact roll to make The surface of the aforementioned film-like resin is smooth. 7. The method of producing an optical film according to any one of claims 1 to 6, wherein the resin is a deuterated cellulose or a cycloolefin polymer. An optical film produced by the method of producing an optical film according to any one of claims 1 to 7. A polarizing plate characterized in that the optical film of claim 8 is used as a protective film for a polarizing plate. A liquid crystal display device characterized in that the polarizing plate of claim 9 is used. -54-