WO2010001677A1 - Optical film, manufacturing method for optical film, polarizing plate, and liquid crystal display device using same - Google Patents

Optical film, manufacturing method for optical film, polarizing plate, and liquid crystal display device using same Download PDF

Info

Publication number
WO2010001677A1
WO2010001677A1 PCT/JP2009/060048 JP2009060048W WO2010001677A1 WO 2010001677 A1 WO2010001677 A1 WO 2010001677A1 JP 2009060048 W JP2009060048 W JP 2009060048W WO 2010001677 A1 WO2010001677 A1 WO 2010001677A1
Authority
WO
WIPO (PCT)
Prior art keywords
optical film
film
cellulose ester
liquid crystal
ester
Prior art date
Application number
PCT/JP2009/060048
Other languages
French (fr)
Japanese (ja)
Inventor
隆嗣 鈴木
Original Assignee
コニカミノルタオプト株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by コニカミノルタオプト株式会社 filed Critical コニカミノルタオプト株式会社
Priority to JP2010518966A priority Critical patent/JPWO2010001677A1/en
Publication of WO2010001677A1 publication Critical patent/WO2010001677A1/en

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films or sheets
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/0008—Organic ingredients according to more than one of the "one dot" groups of C08K5/01 - C08K5/59
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L1/00—Compositions of cellulose, modified cellulose or cellulose derivatives
    • C08L1/08—Cellulose derivatives
    • C08L1/10—Esters of organic acids, i.e. acylates
    • C08L1/14—Mixed esters, e.g. cellulose acetate-butyrate
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
    • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3083—Birefringent or phase retarding elements
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2301/00—Characterised by the use of cellulose, modified cellulose or cellulose derivatives
    • C08J2301/08—Cellulose derivatives
    • C08J2301/14—Mixed esters
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G02F1/133528—Polarisers

Definitions

  • the present invention relates to an optical film comprising a cellulose ester, a method for producing the optical film, a polarizing plate using the same, and a liquid crystal display device.
  • Optical film made of cellulose ester protects photographic negative film supports and polarizers used in liquid crystal displays due to its high transparency, low birefringence, and easy adhesion to polarizers. As an optical film, it has been widely used for polarizing plates and the like.
  • liquid crystal display devices various functional films such as retardation films, viewing angle widening films, antireflection films used in plasma displays, and various functional films used in organic EL displays, etc. Can also be used.
  • the solution casting method is a film forming method in which a solution obtained by dissolving cellulose ester in a solvent is cast to obtain a film shape, and then the solvent is evaporated and dried to obtain a film. Since a film formed by the solution casting method has high flatness, a high-quality liquid crystal display device without unevenness can be obtained using the film.
  • the solution casting method requires a large amount of an organic solvent and has a problem that the environmental load is large. Because optical films are formed using halogen-based solvents with high environmental impact due to their dissolution characteristics, reduction of solvent usage is particularly required, and production of optical films should be increased by solution casting film formation. Has become difficult. For this reason, the film forming method which does not use an organic solvent, for example, the film forming method by heat melting is desired.
  • cellulose triacetate which is a cellulose ester generally used in solution casting film formation
  • cellulose triacetate is a cellulose ester whose decomposition start temperature is lower than the melting start temperature, It is difficult to use for melt casting film formation.
  • melt casting film formation casting is cast from a die to a cooling drum in a state where the viscosity at the time of melting is high, so that the leveling of the film is poor, and variation in retardation (retardation) occurs compared to solution casting film formation.
  • retardation retardation
  • a phase difference film is used to increase the viewing angle or improve the contrast of a liquid crystal display device.
  • retardation films have been developed by stretching a cellulose ester film, saponified and bonded to a polarizer, and a polarizing plate protective film having a retardation film function has been realized (for example, Patent Documents). 4).
  • the number of steps and the number of parts are small and a significant cost reduction is achieved as compared with the case where a retardation film is bonded to a conventional polarizing plate.
  • the retardation film described above is stretched to develop retardation.
  • film thickness unevenness is liable to occur and haze increases. It was found that the adhesion with the polarizer deteriorates.
  • the liquid crystal display device produced using this retardation film had the subject that viewing angle and contrast deteriorated.
  • an optical film having a cellulose ester formed by melt casting having excellent environmental suitability and good quality and productivity.
  • the production method of the optical film, and hence the appearance of a polarizing plate and a liquid crystal display device using the method, are awaited.
  • the optical film contains a cellulose ester, and the cellulose ester satisfies the conditions of the following formulas (1) to (4) at the same time as the type of substituent and the degree of substitution per glucose unit of the cellulose ester.
  • Optical film 1.
  • optical film as described in 1 or 2 above, comprising a polyhydric alcohol ester compound.
  • optical film as described in any one of 1 to 3 above, which comprises a carbohydrate ester compound.
  • optical film as described in any one of 1 to 4 above, which comprises a hindered phenol compound.
  • optical film as described in any one of 1 to 5 above, which comprises a phosphite compound or a phosphonite compound.
  • optical film according to any one of 1 to 7 or the optical film produced by the production method according to any one of 8 to 10 is provided on at least one surface of a polarizer.
  • Polarizer
  • liquid crystal display device as described in 12 above, wherein the liquid crystal cell is a VA liquid crystal cell.
  • the present inventors in the process of intensively studying to solve the above problems, when the type of substituent per glucose unit constituting the cellulose ester and the degree of substitution are within the scope of the present invention, The present inventors have found that all the above problems can be solved and have completed the present invention.
  • an optical film having excellent environmental suitability, good film forming properties, and excellent optical properties more specifically, good stretchability, excellent retardation development, small film thickness unevenness, and haze It was possible to provide an optical film that is low and has good adhesion to a polarizer, and a method for producing the same. Furthermore, it was possible to provide a polarizing plate having good durability over a long period of time and a liquid crystal display device having a wide viewing angle and good durability using the optical film.
  • FIG. 3A is an external view of the main part of the casting die
  • FIG. 3B is a cross-sectional view of the main part of the casting die.
  • the present invention provides an optical film with good productivity and excellent optical properties.
  • optical films such as a high-quality polarizing plate protective film, a retardation film, and an antireflection film, and it is possible to obtain a liquid crystal display device with high display quality.
  • the optical film of the present invention may be an optical film produced by either a solution casting method or a melt casting method, but in view of environmental suitability, the melt casting method is preferred.
  • the optical film forming material is heated to a molten state without dissolving the optical film in a solvent as in solution casting, and casting is defined as a melt casting method. .
  • the molding method for heating and melting can be further classified into a melt extrusion molding method, a press molding method, an inflation method, an injection molding method, a blow molding method, a stretch molding method, and the like. Among these, in order to obtain an optical film excellent in mechanical strength and surface accuracy, the melt extrusion method is excellent.
  • a method in which the optical film forming material is heated to develop its fluidity and then extruded and formed on a drum or an endless belt is a preferred embodiment as the melt casting method of the present invention.
  • the optical film of the present invention is formed by melt-casting an optical film-forming material containing at least one of the following cellulose esters, preferably at a melting temperature of 200 ° C. or higher and 270 ° C. or lower.
  • An optical film is particularly preferable.
  • the cellulose ester used in the present invention is a cellulose ester that simultaneously satisfies the following formulas (1) to (4) when the substitution degree of the acetyl group is X and the substitution degree of the propionyl group is Y.
  • Such cellulose esters are usually called cellulose acetate propionate. Note that satisfying any one, any two, or any three of the following formulas does not solve all of the above problems, but it is important to satisfy all four simultaneously.
  • Formula (1) 6.30 ⁇ 2 ⁇ X + 3 ⁇ Y ⁇ 6.80
  • Formula (2) 2.35 ⁇ X + Y ⁇ 2.55
  • Formula (4) 1.45 ⁇ Y ⁇ 1.75
  • In the formula (3) it is preferable that 0.75 ⁇ X ⁇ 1.05 from the viewpoint that the effect of the present invention is further exhibited.
  • the formula (4) it is preferable that 1.50 ⁇ Y ⁇ 1.75 because the effects of the present invention are further exhibited.
  • Cellulose has a total of three hydroxyl groups, one at each of the 2nd, 3rd and 6th positions of 1 glucose unit.
  • the total degree of substitution is the average number of acyl groups bonded to 1 glucose unit. It is a numerical value indicating whether or not. Accordingly, the maximum degree of substitution is 3.00, and the portion not substituted with the acyl group is usually present as a hydroxyl group.
  • the 2nd and 3rd positions are secondary hydroxyl groups, and the 6th position is a primary hydroxyl group, which changes to the higher order structure and physical properties of the cellulose ester depending on which position the acetyl group and propionyl group are substituted in. Accompanied by.
  • a cellulose ester in which some or all of the hydroxyl groups of cellulose are substituted with acyl groups is referred to as a cellulose ester.
  • X is the sum of the average degree of substitution by the 2-, 3-, and 6-position acetyl groups
  • Y is the sum of the average degree of substitution by the 2-, 3-, and 6-position propionyl groups.
  • the cellulose ester satisfying the above formulas (1) to (4) simultaneously (the average degree of substitution is simply referred to as the degree of substitution).
  • the degree of substitution between the acetyl group and the propionyl group was determined by the method prescribed in ASTM D817-96.
  • the formula (1) represents the range of the average total carbon number of the acyl group substituted per glucose unit of the cellulose ester. That is, since the carbon number of the acetyl group is 2 and the carbon number of the propionyl group is 3, “2 ⁇ X + 3 ⁇ Y” multiplied by the respective substitution degrees is the total carbon number. According to the inventor's study, if the total number of carbons is small, the hydrophilicity is high and the adhesion to the polarizer is high, but on the other hand, it is inferior in melt film-forming properties. While it was excellent in film properties, it was found that the adhesion to the polarizer was low.
  • the formula (2) represents the range of the average total degree of substitution (X + Y) of acyl groups substituted per glucose unit of the cellulose ester.
  • retardation is likely to be manifested when the total degree of substitution is small, whereas the haze tends to be high when stretched, and conversely, when the total degree of substitution is large, the haze when stretched is low, but the retardation is low. It was found that it was difficult to express.
  • the degree of substitution of the acetyl group of the formula (3) and the degree of substitution of the propionyl group of the formula (4) also have an influence on adhesion to the polarizer, melt film-forming property, expression of retardation, and haze. It became clear by examination of the inventor.
  • the cellulose ester used in the present invention is not particularly limited, but preferably has a weight average molecular weight (Mw) of 150,000 to 250,000, more preferably has a weight average molecular weight of 180,000 to 230,000, Most preferably, it has a weight average molecular weight of 10,000 to 220,000.
  • Mw weight average molecular weight
  • the weight average molecular weight is within the above preferred range, it does not cause problems such as an excessively high melt viscosity or reduced strength of the resulting film, which is preferable.
  • the cellulose ester used in the present invention preferably has a weight average molecular weight (Mw) / number average molecular weight (Mn) ratio of 1.3 to 5.5, particularly preferably 1.5 to 5.0. More preferably, it is 1.7 to 4.0, and more preferably 2.0 to 3.5 cellulose ester is preferably used.
  • Mw / Mn exceeds 5.5, the viscosity becomes high and the melt film-forming property tends to decrease, which is not preferable.
  • Mw / Mn exceeds 5.5, the viscosity becomes high and the melt film-forming property tends to decrease, which is not preferable.
  • it is preferably 1.3 or more.
  • Mn and Mw / Mn can be calculated by gel permeation chromatography (GPC) in the following manner.
  • the measurement conditions are as follows.
  • the cellulose ester in the film-forming material is preferably in the range of 70% by mass to 99% by mass, and has excellent melt castability and stability in the presence of additives such as deterioration inhibitors, plasticizers and ultraviolet absorbers described later.
  • the obtained film can impart excellent performance as an optical film.
  • the content of the cellulose ester is 70% by mass or less, the additive bleeds out and the mechanical strength of the film becomes small, which is not preferable.
  • the amount of other additives necessary as an optical film is 1.0% by mass or less (the content of cellulose ester is 99% or more), it is difficult to satisfy the required physical properties. More preferably, the cellulose ester content is 80 to 95% by mass.
  • the raw material cellulose of the cellulose ester used in the present invention may be wood pulp or cotton linter, and the wood pulp may be softwood or hardwood, but softwood is more preferable.
  • a cotton linter is preferably used from the viewpoint of peelability during film formation.
  • the cellulose ester made from these can be mixed suitably or can be used independently.
  • the ratio of cellulose ester derived from cellulose linter: cellulose ester derived from wood pulp (coniferous): cellulose ester derived from wood pulp (hardwood) is 100: 0: 0, 90: 10: 0, 85: 15: 0, 50:50: 0, 20: 80: 0, 10: 90: 0, 0: 100: 0, 0: 0: 100, 80:10:10, 85: 0: 15, 40:30:30.
  • the cellulose ester of the present invention can be synthesized with reference to known methods.
  • the acetyl group and propionyl group can be substituted by acetylating and propionating the hydroxyl group of the raw material cellulose by acetic anhydride and propionic anhydride by a conventional method.
  • the method for synthesizing such a cellulose ester is not particularly limited, and for example, it can be synthesized with reference to the method described in JP-A-10-45804 or JP-A-6-501040. It should be noted that a cellulose ester that simultaneously satisfies the above formulas (1) to (4) can be synthesized by appropriately changing the amounts of acetic anhydride and propionic anhydride used.
  • the alkaline earth metal content of the cellulose ester used in the present invention is preferably in the range of 1 to 50 ppm. If it exceeds 50 ppm, lip adhesion stains increase or breakage tends to occur at the slitting part during or after hot stretching. Even if it is less than 1 ppm, it tends to break, but the reason is not well understood. Further, the range of 1 to 30 ppm is preferable.
  • the alkaline earth metal as used herein refers to the total content of Ca and Mg, and can be measured using an X-ray photoelectron spectrometer (XPS).
  • the residual sulfuric acid content in the cellulose ester used in the present invention is preferably in the range of 0.1 to 45 ppm in terms of elemental sulfur. These are considered to be contained in the form of salts. If the residual sulfuric acid content exceeds 45 ppm, the deposits on the die lip during heat melting increase, such being undesirable. Moreover, since it becomes easy to fracture
  • the residual sulfuric acid content can be measured by the method prescribed in ASTM D817-96.
  • the free acid content in the cellulose ester used in the present invention is preferably 1 to 500 ppm. If it exceeds 500 ppm, deposits on the die lip will increase and breakage will easily occur. Further, it is preferably in the range of 1 to 100 ppm, and it becomes more difficult to break. The range of 1 to 70 ppm is particularly preferable.
  • the free acid content can be measured by the method prescribed in ASTM D817-96.
  • the residual alkaline earth metal content, residual sulfuric acid content, and residual acid content are within the above ranges. This is preferable.
  • cellulose ester can be washed with a poor solvent such as methanol or ethanol, or as a result, a mixed solvent of a poor solvent and a good solvent can be used as a poor solvent. Low molecular organic impurities can be removed. Further, the washing of the cellulose ester is also preferably performed in the presence of a deterioration inhibitor, and the heat resistance and film forming stability of the cellulose ester are improved.
  • cellulose ester In order to improve the heat resistance, mechanical properties, optical properties, etc. of cellulose ester, dissolve it in a good solvent of cellulose ester, reprecipitate it in a poor solvent, filter it, or stir and suspend it in the poor solvent. The low molecular weight component of cellulose ester and other impurities can be removed by filtration. At this time, it is preferable to carry out in the presence of a deterioration preventing agent, similarly to the above-described washing of the cellulose ester.
  • the deterioration inhibitor used for washing the cellulose ester may remain in the cellulose ester after washing.
  • the residual amount is preferably 0.01 to 2000 ppm, more preferably 0.05 to 1000 ppm. More preferably, it is 0.1 to 100 ppm.
  • Another polymer or a low molecular weight compound may be added after the reprecipitation treatment of the cellulose ester.
  • the cellulose ester used in the present invention preferably has few bright spot foreign matters when formed into a film.
  • a bright spot foreign material is an arrangement in which two polarizing plates are arranged orthogonally (crossed Nicols), a cellulose ester film is arranged between them, light from the light source is applied from one side, and the cellulose ester film is applied from the other side. This is the point where the light from the light source appears to leak when observed.
  • the polarizing plate used for the evaluation is desirably composed of a protective film having no bright spot foreign matter, and a polarizing plate using a glass plate for protecting the polarizer is preferably used.
  • One of the causes of bright spot foreign matter is the unacetylated or low acetylated cellulose contained in the cellulose ester.
  • Use a cellulose ester with less bright spot foreign matter (use a cellulose ester with a small dispersion degree of substitution).
  • 0.01 mm or more is preferably 200 pieces / cm 2 or less, more preferably 100 pieces / cm 2 or less, further preferably 50 pieces / cm 2 or less, and 30 pieces / cm 2 or less. More preferably, it is more preferably 10 pieces / cm 2 or less, but most preferably none.
  • the number of bright spots of 0.005 to 0.01 mm or less is also preferably 200 / cm 2 or less, more preferably 100 / cm 2 or less, and 50 / cm 2 or less. Even more preferred is 30 / cm 2 or less, still more preferred is 10 / cm 2 or less, and most preferred is none.
  • filtering the cellulose ester composition to which a deterioration inhibitor, a plasticizer, etc. are added and mixed is more effective than filtering the melted cellulose ester alone.
  • High efficiency is preferable.
  • the cellulose ester may be dissolved in a solvent during the synthesis and reduced by filtration. What mixed the ultraviolet absorber and other additives suitably can be filtered. Filtration is preferably performed at a viscosity of a melt containing cellulose ester of 10,000 Pa ⁇ s or less, more preferably 5000 Pa ⁇ s or less, even more preferably 1000 Pa ⁇ s or less, and even more preferably 500 Pa ⁇ s or less. .
  • the filter medium conventionally known materials such as glass fibers, cellulose fibers, filter paper, and fluorine resins such as tetrafluoroethylene resin are preferably used, and ceramics, metals and the like are particularly preferably used.
  • the absolute filtration accuracy is preferably 50 ⁇ m or less, more preferably 30 ⁇ m or less, still more preferably 10 ⁇ m or less, and even more preferably 5 ⁇ m or less. These can be used in combination as appropriate.
  • the filter medium can be either a surface type or a depth type, but the depth type is preferably used because it is relatively less clogged.
  • the cellulose ester obtained by dissolving the raw material cellulose ester at least once in a solvent and then drying the solvent may be used.
  • a cellulose ester which has been dissolved in a solvent together with at least one of a deterioration inhibitor, a plasticizer, an ultraviolet absorber and a matting agent and then dried is used.
  • the solvent a good solvent used in a solution casting method such as methylene chloride, methyl acetate or dioxolane can be used, and a poor solvent such as methanol, ethanol or butanol may be used at the same time. In the course of dissolution, it may be cooled to ⁇ 20 ° C. or lower or heated to 80 ° C. or higher.
  • each additive in a molten state can be easily made uniform, and optical characteristics can be made uniform.
  • ⁇ Plasticizer ⁇ it is preferable to add at least one plasticizer to the optical film.
  • a plasticizer is an additive having an effect of improving brittleness or imparting flexibility by adding it to a polymer.
  • a plasticizer is added.
  • effects such as improvement of mechanical properties of optical film, improvement of tearing strength, provision of water absorption resistance, reduction of moisture permeability, etc. can be seen. Therefore, it is more preferable to use a material having such an effect as a plasticizer. preferable.
  • plasticizer for example, phosphate ester plasticizer, polyhydric alcohol ester plasticizer (ethylene glycol ester plasticizer, glycerin ester plasticizer, diglycerin ester plasticizer, etc.), examples thereof include polyvalent carboxylic acid ester plasticizers, carbohydrate ester plasticizers, and polymer plasticizers.
  • polyhydric alcohol ester plasticizers are preferred, and polyhydric alcohol ester plasticizers and carbohydrate ester plasticizers are more preferred.
  • the plasticizer may be a liquid or a solid, and is preferably colorless due to the restrictions of the composition.
  • the addition amount may be as long as it does not adversely affect the optical properties and mechanical properties, and the blending amount is appropriately selected within the range not impairing the object of the present invention, and is preferably 1 to 25 with respect to the mass of the cellulose ester according to the present invention. It is an optical film characterized by containing mass%. When the content is less than 1% by mass, the effect of improving the flatness is not recognized, and when the content is more than 25% by mass, bleeding out easily occurs and the temporal stability of the film decreases, which is not preferable.
  • optical film containing 3 to 20% by mass of a plasticizer More preferred is an optical film containing 5 to 15% by mass.
  • an ester plasticizer comprising a polyhydric alcohol and a monovalent carboxylic acid
  • an ester plasticizer comprising a polyvalent carboxylic acid and a monohydric alcohol
  • An ester plasticizer composed of an alcohol and a monovalent carboxylic acid is particularly preferable because the affinity with the cellulose ester is further increased.
  • Examples of the polyhydric alcohol that is a raw material of the ester plasticizer that is preferably used in the present invention include the following, but the present invention is not limited thereto.
  • ethylene glycol ethylene
  • Examples of preferred organic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, pivalic acid, acrylic acid, methacrylic acid, cyclohexanecarboxylic acid, benzoic acid, anisic acid, 3,4,5-trimethoxybenzoic acid, toluyl Acid, tert-butylbenzoic acid, naphthoic acid, picolinic acid, and the like.
  • Polyhydric alcohol ester is formed by unsaturated carboxylic acid, for example, aromatic carboxylic acid, which is highly effective in reducing the moisture permeability of cellulose ester. It is preferable.
  • the organic acid used for the polyhydric alcohol ester may be one kind or a mixture of two or more kinds. Moreover, all the OH groups in the polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are.
  • ethylene glycol ester plasticizers that are one of the polyhydric alcohol esters include ethylene glycol alkyl ester plasticizers such as ethylene glycol diacetate and ethylene glycol dibutyrate, and ethylene glycol dicyclopropyl.
  • ethylene glycol cycloalkyl ester plasticizers such as carboxylate and ethylene glycol dicyclohexylcarboxylate
  • ethylene glycol aryl ester plasticizers such as ethylene glycol dibenzoate and ethylene glycol di4-methylbenzoate.
  • alkylate groups may be the same or different, and may be further substituted.
  • alkylate group cycloalkylate group and arylate group
  • substituents may be bonded by a covalent bond.
  • the ethylene glycol part may be substituted, and the ethylene glycol ester partial structure may be part of the polymer or regularly pendant, and may be an antioxidant, an acid scavenger, an ultraviolet absorber, etc. It may be introduced into a part of the molecular structure of the additive.
  • glycerin ester plasticizers that are one of the polyhydric alcohol esters include glycerol alkyl esters such as triacetin, tributyrin, glycerol diacetate caprylate, glycerol oleate propionate, and glycerol tricyclopropylcarboxylate.
  • Glycerol glycerol esters such as glycerol tricyclohexyl carboxylate, glycerol aryl esters such as glycerol tribenzoate and glycerol 4-methylbenzoate, diglycerol tetraacetylate, diglycerol tetrapropionate, diglycerol acetate tricaprylate, diglycerol Diglycerol alkyl esters such as tetralaurate, diglycerol tetracyclobutylcarboxylate, diglycerol Diglycerol cycloalkyl esters such as La cyclopentyl carboxylate, diglycerin tetrabenzoate, diglycerin aryl ester such as diglycerin 3-methylbenzoate or the like.
  • These alkylate groups, cycloalkylcarboxylate groups, and arylate groups may be the same or different, and may be further substituted.
  • the glycerin and diglycerin part may be substituted, the partial structure of the glycerin ester and the diglycerin ester may be part of the polymer or regularly pendant, and the antioxidant, acid scavenger, You may introduce
  • polyhydric alcohol ester plasticizers include polyhydric alcohol ester plasticizers described in paragraphs 30 to 33 of JP-A No. 2003-12823, pentaerythritol tetrabenzoate, and the like.
  • alkylate groups, cycloalkylcarboxylate groups, and arylate groups may be the same or different, and may be further substituted. Moreover, the mix of alkylate group, a cycloalkyl carboxylate group, and an arylate group may be sufficient, and these substituents may couple
  • the polyhydric alcohol part may be substituted, and the partial structure of the polyhydric alcohol may be part of the polymer or regularly pendant, and may be an antioxidant, an acid scavenger, an ultraviolet absorber. May be introduced into a part of the molecular structure of the additive.
  • alkyl polyhydric alcohol aryl esters are preferred.
  • the above-mentioned ethylene glycol dibenzoate, glycerin tribenzoate, diglycerin tetrabenzoate examples thereof include the exemplified compound 16 described in paragraph 31 of JP-A-2003-12823.
  • Alkyl dicarboxylic acid cycloalkyl ester plasticizers such as cyclopentyl succinate and dicyclohexyl adipate, alkyl dicarboxylic acid aryl ester plasticizers such as diphenyl succinate and di4-methylphenyl glutarate, dihexyl-1,4-cyclohexane
  • Cycloalkyl dicarboxylic acid alkyl ester plasticizers such as dicarboxylate and didecylbicyclo [2.2.1] heptane-2,3-dicarboxylate, dicyclohexyl-1,2-cyclobutanedicarboxylate, Cyclopropyl-1,2-cyclohexyl dicarboxylate and other cycloalkyl dicarboxylic acid cycloalkyl ester plasticizers, diphenyl-1,1-cyclopropyl dicarboxylate, di-2-naphthyl-1,4-cyclohex
  • alkoxy groups and cycloalkoxy groups may be the same or different, may be mono-substituted, and these substituents may be further substituted.
  • the alkyl group and cycloalkyl group may be mixed, or these substituents may be bonded together by a covalent bond.
  • the aromatic ring of phthalic acid may be substituted, and a multimer such as a dimer, trimer or tetramer may be used.
  • the partial structure of phthalate ester may be part of the polymer or regularly pendant to the polymer, and it may be part of the molecular structure of additives such as antioxidants, acid scavengers, and UV absorbers. It may be introduced.
  • polycarboxylic acid ester plasticizers include alkyl polycarboxylic acid alkyl esters such as tridodecyl tricarbarate and tributyl-meso-butane-1,2,3,4-tetracarboxylate.
  • Plasticizers alkylpolycarboxylic acid cycloalkylester plasticizers such as tricyclohexyl tricarbarate, tricyclopropyl-2-hydroxy-1,2,3-propanetricarboxylate, triphenyl 2-hydroxy- Alkyl polyvalent carboxylic acid aryl ester plasticizers such as 1,2,3-propanetricarboxylate, tetra-3-methylphenyltetrahydrofuran-2,3,4,5-tetracarboxylate, tetrahexyl-1,2, 3,4-cyclobutanetetracarboxylate, tetra Cycloalkyl polycarboxylic acid alkyl ester plasticizers such as til-1,2,3,4-cyclopentanetetracarboxylate, tetracyclopropyl-1,2,3,4-cyclobutanetetracarboxylate, tricyclohexyl- Cycloalkyl polycarboxylic acid cycloalkyl este
  • Plasticizers of aryl polyvalent carboxylic acid aryl esters such as plasticizers triphenylbenzene-1,3,5-tetracarboxylate, hexa-4-methylphenylbenzene-1,2,3,4,5,6-hexacarboxylate Agents.
  • alkoxy groups and cycloalkoxy groups may be the same or different, and may be monosubstituted, and these substituents may be further substituted.
  • the alkyl group and cycloalkyl group may be mixed, or these substituents may be bonded together by a covalent bond.
  • the aromatic ring of phthalic acid may be substituted, and a multimer such as a dimer, trimer or tetramer may be used.
  • the partial structure of phthalate ester may be part of the polymer or regularly pendant into the polymer, and introduced into part of the molecular structure of additives such as antioxidants, acid scavengers, UV absorbers, etc. May be.
  • alkyl dicarboxylic acid alkyl esters are preferable, and specific examples include the dioctyl adipate.
  • plasticizers used in the present invention include phosphate ester plasticizers, carbohydrate ester plasticizers, polymer plasticizers, and the like.
  • phosphoric acid ester plasticizer examples include phosphoric acid alkyl esters such as triacetyl phosphate and tributyl phosphate, phosphoric acid cycloalkyl esters such as tricyclopentyl phosphate and cyclohexyl phosphate, triphenyl phosphate, and trichlorate.
  • Examples thereof include phosphoric acid aryl esters such as zil phosphate, cresyl phenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, trinaphthyl phosphate, trixylyl phosphate, tris ortho-biphenyl phosphate.
  • phosphoric acid aryl esters such as zil phosphate, cresyl phenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, trinaphthyl phosphate, trixylyl phosphate, tris ortho-biphenyl phosphate.
  • substituents may be the same or different, and may be further substituted.
  • alkylene bis (dialkyl phosphate) such as ethylene bis (dimethyl phosphate), butylene bis (diethyl phosphate), alkylene bis (diaryl phosphate) such as ethylene bis (diphenyl phosphate), propylene bis (dinaphthyl phosphate), phenylene bis (dibutyl) Phosphate), arylene bis (dialkyl phosphate) such as biphenylene bis (dioctyl phosphate), phosphate esters such as arylene bis (diaryl phosphate) such as phenylene bis (diphenyl phosphate) and naphthylene bis (ditoluyl phosphate).
  • substituents may be the same or different, and may be further substituted.
  • it may be a mix of an alkyl group, a cycloalkyl group, and an aryl group, and the substituents may be covalently bonded to each other.
  • the partial structure of phosphate ester may be part of the polymer, or may be regularly pendant, and also introduced into part of the molecular structure of additives such as antioxidants, acid scavengers, UV absorbers, etc. May be.
  • additives such as antioxidants, acid scavengers, UV absorbers, etc. May be.
  • phosphoric acid aryl ester and arylene bis (diaryl phosphate) are preferable, and specifically, triphenyl phosphate and phenylene bis (diphenyl phosphate) are preferable.
  • the carbohydrate means a monosaccharide, disaccharide or trisaccharide in which the saccharide is present in the form of pyranose or furanose (6-membered ring or 5-membered ring).
  • Non-limiting examples of carbohydrates include glucose, saccharose, lactose, cellobiose, mannose, xylose, ribose, galactose, arabinose, fructose, sorbose, cellotriose and raffinose.
  • Carbohydrate ester refers to an ester compound formed by dehydration condensation of a hydroxyl group of a carbohydrate and a carboxylic acid, and specifically means an aliphatic carboxylic acid ester or an aromatic carboxylic acid ester of a carbohydrate.
  • the aliphatic carboxylic acid include acetic acid and propionic acid
  • examples of the aromatic carboxylic acid include benzoic acid, toluic acid, and anisic acid.
  • Carbohydrates have a number of hydroxyl groups depending on the type, but even if a part of the hydroxyl group reacts with the carboxylic acid to form an ester compound, the whole hydroxyl group reacts with the carboxylic acid to form an ester compound. Also good.
  • carbohydrate ester plasticizer examples include glucose pentaacetate, glucose pentapropionate, glucose pentabtylate, saccharose octaacetate, saccharose octabenzoate and the like. Among these, saccharose octaacetate, saccharose Octabenzoate is more preferred, and sucrose octabenzoate is particularly preferred.
  • the above-mentioned type of carbohydrate ester plasticizer is commercially available from Daiichi Kogyo Seiyaku Co., Ltd. under the trade names “Monopet SB” and “Monopet SOA”.
  • polymer plasticizer examples include aliphatic hydrocarbon polymers, alicyclic hydrocarbon polymers, polyethyl acrylate, polymethyl methacrylate, methyl methacrylate and 2-hydroxyethyl methacrylate.
  • Polymers acrylic polymers such as copolymers of methyl methacrylate, methyl acrylate and 2-hydroxyethyl methacrylate, vinyl polymers such as polyvinyl isobutyl ether and poly N-vinyl pyrrolidone, polystyrene, poly 4-hydroxy Examples thereof include styrene polymers such as styrene, polyesters such as polybutylene succinate, polyethylene terephthalate and polyethylene naphthalate, polyethers such as polyethylene oxide and polypropylene oxide, polyamides, polyurethanes and polyureas.
  • the number average molecular weight is preferably about 1,000 to 500,000, particularly preferably 5,000 to 200,000. If it is 1000 or less, a problem arises in volatility, and if it exceeds 500000, the plasticizing ability is lowered, and the mechanical properties of the optical film are adversely affected.
  • These polymer plasticizers may be a homopolymer composed of one type of repeating unit or a copolymer having a plurality of repeating structures. Two or more of the above polymers may be used in combination.
  • the optical film of the present invention preferably contains 1 to 25% by mass of an ester plasticizer comprising a polyhydric alcohol and a monovalent carboxylic acid, or a carbohydrate ester plasticizer, but in combination with other plasticizers. Also good.
  • the ester plasticizer comprising a polyhydric alcohol and a monovalent carboxylic acid which is a preferred plasticizer in the optical film of the present invention, is an ester plasticizer comprising a trivalent or higher alcohol and a monovalent carboxylic acid in phase with the cellulose ester. Because it has high solubility and can be added at a high addition rate, it does not cause bleed-out even when other plasticizers and additives are used in combination. The agent is most preferable because it can be easily used in combination.
  • the deterioration preventing agent is a material that suppresses decomposition of a polymer by heat, oxygen, moisture, acid, or the like by a chemical action. Since the optical film of the present invention is molded particularly at a high temperature of 200 ° C. or higher, it is a system in which the polymer is easily decomposed and deteriorated, and it is preferable to contain a deterioration inhibitor in the optical film.
  • Decomposition reactions that have not been elucidated, such as oxidation prevention of optical films, capture of acid generated by decomposition, and suppression or prohibition of decomposition reaction due to radical species due to light or heat.
  • Deterioration inhibitors are used to suppress the generation of volatile components due to alteration or material decomposition.
  • the deterioration preventing agent in the optical film-forming material of the present invention can be selected from at least one or more.
  • the amount to be added is 0.01% by mass or more with respect to the mass of the cellulose ester of the present invention. 10 mass% or less is preferable, More preferably, it is 0.1 to 5.0 mass%, More preferably, it is 0.2 to 2.0 mass%.
  • the addition amount of the deterioration preventing agent is within the above range because the transparency as the optical film is improved from the viewpoint of compatibility with the cellulose ester and the optical film is not brittle.
  • the optical film can be stored by dividing the constituent material into one or more kinds of pellets for the purpose of avoiding material alteration and hygroscopicity. Pelletization may improve the mixing or compatibility of the melt during heating, or may ensure the optical uniformity of the resulting film.
  • the presence of the above-mentioned deterioration preventing agent is caused by deterioration of the material It is excellent in terms of reducing the strength based on the decomposition and deterioration of optical transparency, or maintaining the strength inherent to the material.
  • optical film is significantly deteriorated by heating, coloring may occur and the optical film may not be used.
  • a retardation imparting step is carried out next to the casting step, but when the optical film is significantly deteriorated by heating, the formed film becomes The film may become brittle and may be easily broken during the stretching process, or the retardation value of the target retardation film may not be expressed.
  • the deterioration of the optical film is unfavorable because it interferes with the bonding with the polarizer.
  • the presence of the above-mentioned deterioration preventing agent suppresses the generation of a colored material in the visible light region at the time of heating and melting, or a volatile component generated by decomposition of the material constituting the film at the time of heating and melting. It is also excellent in that deterioration unfavorable as an optical film such as a decrease in transmittance and haze value caused by the above can be suppressed or eliminated.
  • the display image of the liquid crystal display device is affected when the haze value exceeds 1% when the optical film of the present invention is used. Therefore, the haze value is preferably less than 1%, more preferably less than 0.5%. is there.
  • yellowness yellow index, YI
  • YI yellow index
  • Yellowness can be measured based on JIS-K-7103.
  • reducing the humidity and oxygen concentration in the air can also be preferably used in combination for realizing the present invention.
  • the optical film of the present invention is also used as a polarizing plate protective film, from the viewpoint of improving the storage stability with time with respect to the polarizing plate of the present invention and the polarizer constituting the polarizing plate, the above-mentioned in the optical film.
  • the presence of an anti-degradation agent plays an important role.
  • the storage stability of the optical film over time can be improved from the viewpoint of suppressing the above-mentioned deterioration and deterioration, and the liquid crystal Also in improving the display quality of the display device, the optical compensation design is excellent in that the function can be expressed over a long period of time.
  • the optical film of the present invention preferably contains an antioxidant as a stabilizer.
  • the film molding material is preferably decomposed by heat and oxygen, so that an antioxidant is preferably contained.
  • the antioxidant useful in the present invention can be used without limitation as long as it is a compound that suppresses deterioration of the film-forming material due to oxygen.
  • useful antioxidants include phenolic compounds, phosphorus compounds, Sulfur compounds, acrylate compounds, benzofuranone compounds, oxygen scavengers and the like can be mentioned, and among these, phenol compounds, phosphorus compounds, acrylate compounds, and benzofuranone compounds are particularly preferable. By blending these compounds, it is possible to prevent coloration or strength reduction of the molded product due to heat, thermal oxidation deterioration, or the like without reducing transparency, heat resistance, and the like. These antioxidants can be used alone or in combination of two or more.
  • One antioxidant useful in the present invention is a phenolic compound.
  • Phenol compounds are known compounds, and in addition to alkyl group-substituted phenols such as para-t-butylphenol and para- (1,1,3,3-tetramethylbutyl) phenol, for example, US Pat. No. 4,839, Examples include 2,6-dialkylphenol derivative compounds, so-called hindered phenol compounds, described in columns 12 to 14 of the specification of No. 405, and among these, hindered phenol compounds are preferred.
  • hindered phenol phenol compound examples include n-octadecyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) -propionate, n-octadecyl 3- (3,5-di-t- Butyl-4-hydroxyphenyl) -acetate, n-octadecyl 3,5-di-t-butyl-4-hydroxybenzoate, n-hexyl 3,5-di-t-butyl-4-hydroxyphenylbenzoate, n-dodecyl 3,5-di-t-butyl-4-hydroxyphenylbenzoate, neo-dodecyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, dodecyl ⁇ (3,5-di-t-butyl-4-hydroxyphenyl) propionate, ethyl ⁇ - (4-hydroxy-3,5-di-t-propionat
  • phenolic compounds are commercially available from Ciba Japan, for example, under the trade names “IRGANOX1076” and “IRGANOX1010” and from Sumitomo Chemical Co., Ltd. under the name “Sumizer GA-80”.
  • Preferred phosphorus compounds useful in the present invention include phosphite compounds and phosphonite compounds.
  • Specific examples of the phosphite compound include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4-diphenyl).
  • phosphite compounds are, for example, “Sumilizer GP” from Sumitomo Chemical Co., Ltd., “ADK STAB PEP-24G”, “ADK STAB PEP-36”, “ADK STAB 3010”, “ADK STAB” from ADEKA Co., Ltd. It is commercially available under the trade names “HP-10” and “ADK STAB 2112”.
  • the phosphonite compound examples include dimethyl-phenyl phosphonite, di-t-butyl-phenyl phosphonite, diphenyl-phenyl phosphonite, di- (4-pentyl-phenyl) -phenyl phosphonite, di- (2- t-butyl-phenyl) -phenylphosphonite, di- (2-methyl-3-pentyl-phenyl) -phenylphosphonite, di- (2-methyl-4-octyl-phenyl) -phenylphosphonite, di- ( 3-butyl-4-methyl-phenyl) -phenylphosphonite, di- (3-hexyl-4-ethyl-phenyl) -phenylphosphonite, di- (2,4,6-trimethylphenyl) -phenylphosphonite, Di- (2,3-dimethyl-4-ethyl-phenyl) -phenylphosphonite, di- (2,6-die 3-butylphenyl)
  • sulfur compounds Specific examples of the sulfur compound include dilauryl 3,3-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3-thiodipropionate, lauryl stearyl 3,3-thiodipropioate. And pentaerythritol-tetrakis ( ⁇ -lauryl-thio-propionate), 3,9-bis (2-dodecylthioethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane .
  • acrylate compounds examples include 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2- [1- (2-hydroxy-3, 5 -Di-tert-pentylphenyl) ethyl] -4,6-di-tert-pentylphenyl acrylate and the like.
  • An acrylate compound of the above type is commercially available, for example, from Sumitomo Chemical Co., Ltd. under the trade names “Sumilizer GM” and “Sumilizer GS”.
  • benzofuranone compounds examples include 3- [4- (2-acetoxyethoxy) phenyl] -5,7-ditert-butylbenzofuran-2-one and 5,7-ditert-butyl-3- [4- (2 -Stearoyloxyethoxy) phenyl] benzofuran-2-one, 3,3'-bis [5,7-ditert-butyl-3- (4- [2-hydroxyethoxy] phenyl) benzofuran-2-one], 5 , 7-ditert-butyl-3- (4-methoxyphenyl) benzofuran-2-one, 5,7-ditert-butyl-3-phenylbenzofuran-2-one, 5,7-ditert-butyl-4 -Methyl-3-phenylbenzofuran-2-one, 3- (4-acetoxy-3,5-dimethylphenyl) -5,7-ditert-butylbenzofuran-2-one, 3- (4-acetoxy-3
  • benzofuranone-based compound is commercially available, for example, from Ciba Japan under the trade name “HP-136”.
  • antioxidants 3,4-dihydro-2H-1-benzopyran compounds, 3,3′-spirodichroman compounds, 1,1-spiroindane compounds, morpholine, thiomorpholine, thiomorpholine oxide described in JP-B-08-27508, Examples include thiomorpholine dioxide, compounds having a piperazine skeleton in the partial structure, and oxygen scavengers such as dialkoxybenzene compounds described in JP-A-3-174150.
  • the partial structure of the antioxidant described above may be pendant on a part of the polymer or regularly on the polymer.
  • the antioxidant is preferably removed from impurities such as residual acids, inorganic salts, organic low molecules, etc. that are carried over from production or generated during storage, and more preferably has a purity of 99% or more, like the cellulose ester described above. It is.
  • the residual acid and water are preferably 0.01 to 100 ppm, and when melt-forming the cellulose ester, thermal deterioration can be suppressed, and the film-forming stability, the optical properties and mechanical properties of the film are improved.
  • these antioxidants are each preferably added in an amount of 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, and further preferably 0.1 to 2%, based on the resin. It is preferable to add mass%.
  • antioxidants can obtain a synergistic effect by using several different types of compounds in combination rather than using only one kind.
  • the combined use of a phenol compound, a phosphorus compound having no metal atom, an acrylate compound, and a benzofuranone compound is preferable.
  • the cellulose ester is preferably washed in the presence of an antioxidant during suspension washing with a poor solvent.
  • the antioxidant to be used is not limited as long as it is a compound that inactivates radicals generated in the cellulose ester or suppresses deterioration of the cellulose ester caused by addition of oxygen to the radical generated in the cellulose ester. be able to.
  • the antioxidant used for suspension washing of the cellulose ester may remain in the cellulose ester after washing.
  • the residual amount is preferably 0.01 to 2000 ppm, more preferably 0.05 to 1000 ppm. More preferably, it is 0.1 to 100 ppm.
  • the antioxidant is preferably removed from impurities such as residual acids, inorganic salts, organic low molecules, etc. that are carried over from production or generated during storage, and more preferably has a purity of 99% or more, like the cellulose ester described above. It is. Residual acid and water are preferably 0.01 to 100 ppm, and when melt casting film formation of cellulose ester, thermal deterioration can be suppressed, and film formation stability, optical properties and mechanical properties of the film are improved. To do.
  • hindered amine light stabilizers include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) succinate, bis ( 1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (N-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (N-benzyloxy-2, 2,6,6-tetramethyl-4-piperidyl) sebacate, bis (N-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6) -Pentamethyl-4-piperidyl) 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-butylmalonate, bis (1-acryloyl-2,2,6,6) Tetramethyl-4-piperidyl) 2,2-bis (3,5-di-t-butyl)
  • Mn molecular weight of 2,000 to 5,000 is preferred.
  • Hindered amine compounds of the above type are commercially available, for example, from Ciba Japan Co., Ltd. under the trade names “TINUVIN 144” and “TINUVIN 770” and from ADEKA Co., Ltd. under the name “ADK STAB LA-52”.
  • the hindered amine light stabilizer is preferably added in an amount of 0.1 to 10% by mass, more preferably 0.2 to 5% by mass, based on the mass of the cellulose ester according to the present invention. Further, it is preferable to add 0.5 to 2% by mass. Two or more of these may be used in combination.
  • the cellulose ester is preferably decomposed by an acid in a high temperature environment in which melt film formation is performed. Therefore, the optical film of the present invention preferably contains an acid scavenger as a deterioration preventing agent.
  • Any acid scavenger useful in the present invention can be used without limitation as long as it is a compound that reacts with an acid to inactivate the acid, and is described in U.S. Pat. No. 4,137,201.
  • a compound having an epoxy group is preferred.
  • EPON 815C and other epoxidized ether oligomer condensation products can also be preferably used.
  • acid scavengers that can be used other than the above include oxetane compounds, oxazoline compounds, organic earth salts of alkaline earth metals and acetylacetonate complexes, and paragraphs 68 to 105 of JP-A-5-194788. Is included.
  • the acid scavenger is preferably added in an amount of 0.1 to 10% by mass, more preferably 0.2 to 5% by mass, more preferably 0.2% by mass to the mass of the cellulose ester according to the present invention. It is preferable to add 0.5 to 2% by mass. Two or more of these may be used in combination.
  • the acid scavenger may be referred to as an acid scavenger, an acid scavenger, an acid catcher, or the like, but can be used in the present invention without any difference due to their names.
  • the metal deactivator is preferably added in an amount of 0.0002 to 2 mass%, more preferably 0.0005 to 2 mass%, based on the mass of the cellulose ester according to the present invention. Further, it is preferable to add 0.001 to 1% by mass. Two or more of these may be used in combination.
  • benzotriazole ultraviolet absorbers include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzo Triazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5 Chlorobenzotriazole, 2- (2′-hydroxy-3 ′-(3 ′′, 4 ′′, 5 ′′, 6 ′′ -tetrahydrophthalimidomethyl) -5′-methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2'-hydroxy 3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-
  • TINUVIN 171, TINUVIN 900, TINUVIN 928, TINUVIN 360 (all manufactured by Ciba Japan), LA31 (manufactured by ADEKA Corporation), RUVA- 100 (manufactured by Otsuka Chemical).
  • benzophenone compounds include 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis (2-methoxy-4-hydroxy-) 5-benzoylphenylmethane) and the like, but are not limited thereto.
  • the ultraviolet absorber is preferably added in an amount of 0.1 to 5% by mass, more preferably 0.2 to 3% by mass, and further 0.5 to 2% by mass based on the resin. It is preferable. Two or more of these may be used in combination.
  • the benzotriazole structure or triazine structure may be part of the polymer, or may be regularly pendant to the polymer, and part of the molecular structure of other additives such as plasticizers, antioxidants, and acid scavengers. May be introduced.
  • the conventionally known UV-absorbing polymer is not particularly limited, and examples thereof include a polymer obtained by homopolymerizing RUVA-93 (manufactured by Otsuka Chemical) and a polymer obtained by copolymerizing RUVA-93 with other monomers. . Specifically, PUVA-30M obtained by copolymerizing RUVA-93 and methyl methacrylate in a ratio (mass ratio) of 3: 7, and PUVA-50M copolymerized in a ratio of 5: 5 (mass ratio). It is done. Furthermore, the polymer etc. which are described in Unexamined-Japanese-Patent No. 2003-113317 are mentioned.
  • the cellulose ester can contain various additives in addition to the deterioration inhibitor, the plasticizer and the ultraviolet absorber.
  • various additives in addition to the deterioration inhibitor, the plasticizer and the ultraviolet absorber.
  • matting agents, fillers, inorganic compounds such as silica and silicates, dyes, pigments, phosphors, dichroic dyes, retardation control agents, refractive index regulators, gas permeation inhibitors, antibacterial agents, biodegradable Examples include an imparting agent.
  • additives that are not classified as long as they have the above functions can be used.
  • each material is mixed in a solid or liquid state, heated and melted and kneaded to form a uniform melt, and then cast to form an optical film.
  • the solvent is removed to form a mixture of the additive and the cellulose ester, and this is heated and melted. It may be cast to form an optical film.
  • a matting agent can be added to the optical film of the present invention in order to impart slipperiness, optical and mechanical functions.
  • the matting agent include inorganic compound fine particles and organic compound fine particles.
  • the shape of the matting agent is preferably a spherical shape, rod shape, needle shape, layer shape, flat plate shape or the like.
  • the matting agent include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, and calcium phosphate.
  • examples thereof include inorganic fine particles such as oxides, phosphates, silicates, and carbonates, and crosslinked polymer fine particles.
  • silicon dioxide is preferable because it can reduce the haze of the film.
  • the surface treatment is preferably performed with halosilanes, alkoxysilanes, silazane, siloxane, or the like.
  • halosilanes alkoxysilanes, silazane, siloxane, or the like.
  • the average particle size of the secondary particles of the fine particles is in the range of 0.01 to 1.0 ⁇ m.
  • the average particle size of the primary particles of the fine particles is preferably 5 to 50 nm, more preferably 7 to 14 nm. These fine particles are usually present in the film as aggregates, and are preferably used for generating irregularities with a height of 0.01 to 1.0 ⁇ m on the film surface.
  • Aerosil 200, 200V, 300, R972, R972V, R974, R202, R812, OX50, TT600, NAX50, etc. manufactured by Nippon Aerosil Co., Ltd. are available.
  • P10, KE-P30, KE-P100, KE-P150 and the like can be mentioned. Aerosil 200V, R972V, NAX50, KE-P30 and KE-P100 are preferable. Two or more kinds of these fine particles may be used in combination.
  • Fine particles having different average particle sizes and materials for example, Aerosil 200V and R972V can be used in a mass ratio of 0.1: 99.9 to 99.9: 0.1.
  • matting agents are preferably added by kneading.
  • a matting agent and cellulose ester and / or a plasticizer and / or an antioxidant and / or an ultraviolet absorber previously dispersed in a solvent after mixing and dispersing a matting agent and cellulose ester and / or a plasticizer and / or an antioxidant and / or an ultraviolet absorber previously dispersed in a solvent, a solid substance obtained by volatilizing or precipitating the solvent is obtained. Obtaining and using this in the manufacturing process of the cellulose ester melt is preferable from the viewpoint that the matting agent can be uniformly dispersed in the cellulose ester.
  • the content is preferably 0.001 to 5% by mass, more preferably 0.00. 005 to 1% by mass, more preferably 0.01 to 0.5% by mass.
  • haze value becomes like this. Preferably it is less than 1.0%, More preferably, it is less than 0.5%.
  • the haze value can be measured based on JIS-K-7136.
  • Degradation of the material can be suppressed by reducing the probability that the optical film comes into contact with oxygen in the air, which is preferable for the purpose of the present invention.
  • an optical film is a functional film used for various display apparatuses, such as a liquid crystal display, a plasma display, and an organic electroluminescent display. Specifically, it is a polarizing plate protective film for liquid crystal display apparatuses, retardation film, antireflection Films, brightness enhancement films, hard coat films, antiglare films, antistatic films, optical compensation films such as viewing angle expansion, and the like are included.
  • cellulose ester resins in addition to the cellulose ester of the present invention, cellulose ester resins, cellulose ether resins, vinyl resins (including polyvinyl acetate resins, polyvinyl alcohol resins, etc.), olefins not related to the present invention, and olefins Resin (norbornene resin, monocyclic olefin resin, cyclic conjugated diene resin, vinyl alicyclic hydrocarbon resin, etc.), polyester resin (aromatic polyester, aliphatic polyester, or co-polymer containing them) Coalescence), acrylic resins (including copolymers), polycarbonate resins, polystyrene resins, polysulfone resins, polyarylate resins, and the like.
  • the content of the resin other than the cellulose ester is preferably 0.1 to 30% by mass.
  • the optical film of the present invention is preferably used for a polarizing plate protective film and a retardation film.
  • the optical film of the present invention is preferably produced by a melt casting method.
  • melt casting method can significantly reduce the amount of organic solvent used during film production, the film is much more environmentally friendly than conventional solution casting methods that use large amounts of organic solvents. Therefore, it is preferable to produce an optical film by a melt casting method.
  • the melt casting in the present invention is a method in which cellulose ester is heated and melted to a temperature at which the cellulose ester exhibits fluidity substantially without using a solvent, and a film is formed using this. For example, fluid cellulose ester is removed from a die. This is a method of forming a film by extrusion.
  • a solvent may be used in a part of the process of preparing the molten cellulose ester, in the melt film forming process in which the film is formed into a film, the forming process is substantially performed without using the solvent.
  • the molding method by melt casting can be classified into a melt extrusion molding method, a press molding method, an inflation method, an injection molding method, a blow molding method, a stretch molding method, and the like.
  • the melt extrusion method is excellent for obtaining an optical film having excellent mechanical strength, surface accuracy, and the like.
  • the manufacturing method of the optical film of the present invention will be described by taking the melt extrusion method as an example.
  • FIG. 1 is a schematic flow sheet diagram showing an example of one embodiment of an apparatus for carrying out the method for producing an optical film of the present invention.
  • FIG. 2 is a flow sheet showing an example of an enlarged main part of the manufacturing apparatus of FIG.
  • the optical film is produced by mixing an optical film material such as a cellulose resin, and then using the extruder 1 to melt and extrude from the casting die 4 onto the first cooling roll 5 so as to circumscribe the first cooling roll 5.
  • the optical film 10 is obtained by sequentially circumscribing a total of three cooling rolls, that is, the second cooling roll 7 and the third cooling roll 8, and cooling and solidifying.
  • a touch roll 6 is provided to clamp the molten film on the surface of the first cooling roll 5 in order to correct the flatness.
  • the touch roll 6 has an elastic surface and forms a nip with the first cooling roll 5. Details of the touch roll 6 will be described later.
  • the conditions for melt extrusion can be performed in the same manner as the conditions used for other thermoplastic resins such as polyester.
  • the material is preferably dried beforehand. It is desirable to dry the moisture to 1000 ppm or less, preferably 200 ppm or less by using a vacuum or reduced pressure drier or a dehumidifying hot air drier.
  • a cellulose ester resin dried under hot air, vacuum or reduced pressure is melted at an extrusion temperature of about 200 to 300 ° C. using an extruder 1 and filtered through a leaf disk type filter 2 to remove foreign matters.
  • additives such as plasticizer are not mixed in advance, they may be kneaded in the middle of the extruder. In order to add uniformly, it is preferable to use a mixing apparatus such as a static mixer.
  • the cellulose resin and other additives such as a stabilizer added as necessary are preferably mixed before melting, and more preferably mixed before heating and the cellulose resin.
  • Mixing may be performed by a mixer or the like, or may be mixed in the cellulose resin preparation process as described above.
  • a general mixer such as a V-type mixer, a conical screw type mixer, a horizontal cylindrical type mixer, a Henschel mixer, a ribbon mixer, or the like can be used.
  • the mixture may be directly melted and formed into a film using the extruder 1, but once the optical film constituting material is pelletized, the pellet May be melted by the extruder 1 to form a film.
  • the optical film constituting material includes a plurality of materials having different melting points
  • a so-called braided semi-melt is once produced at a temperature at which only a material having a low melting point is melted, and the semi-melt is extruded into the extruder 1. It is also possible to form a film by putting it into the film.
  • the optical film material contains materials that are easily pyrolyzed, in order to reduce the number of melting times, a method of directly forming a film without producing pellets, or making a braided semi-melt as described above A method of forming a film from is preferred.
  • the extruder 1 can use various types of extruders available on the market, but is preferably a melt-kneading extruder, and may be a single screw extruder or a twin screw extruder.
  • twin-screw extruder When forming a film directly without forming pellets from optical film constituent materials, it is preferable to use a twin-screw extruder because an appropriate degree of kneading is required. However, even with a single-screw extruder, the screw shape can be changed to Maddock. By changing to a kneading type screw such as a mold, unimelt, dalmage, etc., moderate kneading can be obtained, which can be used. When a pellet or braided semi-melt is used as the optical film constituent material, it can be used with either a single screw extruder or a twin screw extruder.
  • the cooling step in the extruder 1 and after the extrusion is preferably performed by substituting with an inert gas such as nitrogen gas or reducing the pressure to reduce the oxygen concentration.
  • the melting temperature of the optical film constituent material in the extruder 1 varies depending on the viscosity and discharge amount of the optical film constituent material, the thickness of the sheet to be manufactured, etc., but is preferably 150 to 300 ° C., more preferably 180 to 270 ° C. 200 to 250 ° C. is more preferable.
  • the melt viscosity at the time of extrusion is 10 to 100,000 poise, preferably 100 to 10,000 poise.
  • the residence time of the optical film constituting material in the extruder 1 is preferably shorter, and is within 5 minutes, preferably within 3 minutes, and more preferably within 2 minutes.
  • the residence time depends on the type of the extruder 1 and the extrusion conditions, it can be shortened by adjusting the material supply amount, L / D, screw rotation speed, screw groove depth, etc. It is.
  • the screw shape, rotation speed, and the like of the extruder 1 are appropriately selected depending on the viscosity and the discharge amount of the optical film constituent material.
  • the shear rate in the extruder 1 is 1 / second to 10,000 / second, preferably 5 / second to 1000 / second, more preferably 10 / second to 100 / second.
  • the extruder 1 that can be used in the present invention is generally available as a plastic molding machine.
  • the slit of the casting die 4 is configured so that the gap can be adjusted.
  • FIG. 3A is an external view showing an example of the main part of the casting die
  • FIG. 3B is a cross-sectional view showing an example of the main part of the casting die.
  • a large number of heat bolts 35 are arranged at a constant pitch in the width direction of the casting die 4, that is, in the length direction of the slit 32.
  • Each heat bolt 35 is provided with a block 36 having an embedded electric heater 37 and a cooling medium passage, and each heat bolt 35 penetrates each block 36 vertically.
  • the base of the heat bolt 35 is fixed to the die body 31, and the tip is in contact with the outer surface of the flexible lip 33. While the block 36 is always air-cooled, the input of the embedded electric heater 37 is increased or decreased to raise or lower the temperature of the block 36, thereby causing the heat bolt 35 to thermally expand and contract, thereby displacing the flexible lip 33 to change the thickness of the optical film. Adjust.
  • Thickness gauges are installed at the required locations in the wake of the die, and the web thickness information detected thereby is fed back to the control device.
  • the thickness information is compared with the set thickness information by the control device, and correction control comes from the same device. It is also possible to control the power or the ON rate of the heat bolt heating element by the amount signal.
  • the heat bolt preferably has a length of 20 to 40 cm and a diameter of 7 to 14 mm, and a plurality of, for example, several tens of heat bolts are preferably arranged at a pitch of 20 to 40 mm.
  • a gap adjusting member mainly composed of a bolt for adjusting the slit gap by manually moving back and forth in the axial direction may be provided.
  • the slit gap adjusted by the gap adjusting member is usually 200 to 1000 ⁇ m, preferably 300 to 800 ⁇ m, more preferably 400 to 600 ⁇ m.
  • the first to third cooling rolls are made of seamless steel pipe with a wall thickness of about 20 to 30 mm, and the surface is mirror finished.
  • a pipe for flowing a cooling liquid is arranged inside the pipe, and the cooling liquid flowing through the pipe can absorb heat from the optical film on the roll.
  • the touch roll 6 in contact with the first cooling roll 5 has an elastic surface and is deformed along the surface of the first cooling roll 5 by the pressing force to the first cooling roll 5. A nip is formed between the two.
  • the touch roll 6 is also called a pinching rotary body.
  • a touch roll disclosed in registered patent 3194904, registered patent 3422798, Japanese Patent Application Laid-Open No. 2002-36332, Japanese Patent Application Laid-Open No. 2002-36333, or the like can be preferably used. These can also use what is marketed. These will be described in more detail below.
  • FIG. 4 is a cross-sectional view showing an example of a pinching rotator.
  • the 1st example of touch roll 6 (henceforth, outline section of touch roll A)) is shown.
  • the touch roll A has an elastic roller 42 disposed inside a flexible metal sleeve 41.
  • the metal sleeve 41 is made of stainless steel having a thickness of 0.3 mm and has flexibility. If the metal sleeve 41 is too thin, the strength is insufficient, whereas if it is too thick, the elasticity is insufficient.
  • the elastic roller 42 presses the metal sleeve 41 against the first cooling roll 5, and the metal sleep 41 and the elastic roller 42 have the shape of the first cooling roll 5. It deforms corresponding to the familiar shape, and forms a nip with the first cooling roll. Cooling water 45 flows in a space formed between the metal sleeve 41 and the elastic roller 42.
  • FIG. 5 is a cross-sectional view taken along a plane perpendicular to the rotation axis, showing a second example (hereinafter referred to as touch roll B) of the pinching rotator.
  • FIG. 6 is a cross-sectional view showing an example of a plane including the rotation axis of the second example (touch roll B) of the pinching rotator.
  • the touch roll B is a flexible and seamless outer tube 51 made of a stainless steel pipe (thickness 4 mm), and a high rigidity arranged in the same axial center inside the outer tube 51.
  • the metal inner cylinder 52 is generally configured.
  • a fluid supply pipe 59 is disposed in the same axial center in a fluid discharge hole 58 formed in the axial center portion of one rotary shaft 55a and forming a fluid return passage 57.
  • the fluid supply pipe 59 is thin-walled. It is connected and fixed to a fluid shaft cylinder 60 arranged at the axial center in the metal outer cylinder 51.
  • Inner cylinder support flanges 61a and 61b are attached to both ends of the fluid shaft cylinder 60, respectively, and a thickness of about 15 to 20 mm between the outer periphery of the inner cylinder support flanges 61a and 61b and the other end side outer cylinder support flange 56b.
  • a metal inner cylinder 52 having a thickness is attached.
  • a cooling liquid flow space 53 of, for example, about 10 mm is formed between the metal inner cylinder 52 and the thin metal outer cylinder 51, and the metal inner cylinder 52 has a flow space 53 and an inner space near both ends.
  • An outlet 52a and an inlet 52b are formed to communicate with the intermediate passages 62a and 62b outside the cylinder support flanges 61a and 61b, respectively.
  • the equivalent spring constant is equal by setting the wall thickness of the outer cylinder 51 to 3 mm compared to the rubber roll of the same shape.
  • the nip width k in the roll rotation direction of the nip is also about 9 mm, which is almost the same as the nip width of this rubber roll of about 12 mm.
  • the deflection amount at the nip width k is about 0.05 to 0.1 mm.
  • the converted value of 2 mm ⁇ t ⁇ 5 mm is 0.008 ⁇ t / r ⁇ 0.05 with respect to a general roll diameter, but in practical use, the roll diameter under the condition of t / r ⁇ 0.03.
  • the wall thickness should be increased in proportion to
  • the touch rolls A and B are urged toward the first cooling roll by the urging means.
  • the value F / W (linear pressure) obtained by dividing the urging force of the urging means by F and dividing the width W of the optical film in the nip along the rotation axis of the first cooling roll 5 is 9.8 to 147 N / Set to cm.
  • a nip is formed between the touch rolls A and B and the first cooling roll 5, and the flatness is corrected while the optical film passes through the nip. Accordingly, the optical film is sandwiched over a long time with a small linear pressure, compared to the case where the touch roll is formed of a rigid body and no nip is formed between the first cooling roll and the flatness is more reliably corrected. be able to.
  • the surfaces of the touch rolls A and B are made of metal, the surfaces of the touch rolls A and B can be made smoother than when the surface of the touch roll is rubber. Can be obtained.
  • ethylene propylene rubber, neoprene rubber, silicon rubber, or the like can be used as a material of the elastic body 44 of the elastic roller 42.
  • the glass transition temperature of the optical film is Tg
  • Tg glass transition temperature
  • the viscosity of the optical film when sandwiching the optical film can be set to an appropriate range, and the die line can be corrected. Further, the surface of the optical film and the roll are uniformly bonded, and the die line can be corrected.
  • the first cooling roll is moved from the position where the melt extruded from the casting die 4 contacts the first cooling roll 5. What is necessary is just to adjust the length L along the rotation direction of the 1st cooling roll 5 of the nip of 5 and the touch roll 6.
  • preferable materials for the first cooling roll 5 and the second cooling roll 7 include carbon steel, stainless steel, resin, and the like.
  • the surface accuracy is preferably increased, and the surface roughness is set to 0.3 S or less, more preferably 0.01 S or less.
  • the above-described die line correction effect is more greatly manifested.
  • the reduced pressure is 50 to 70 kPa.
  • the method of keeping the pressure in the portion from the opening (lip) of the casting die 4 to the first cooling roll 5 at 70 kPa or less but the pressure around the roll from the casting die 4 is covered with a pressure-resistant member, and the pressure is reduced. There are ways to do it.
  • the suction device is preferably subjected to a treatment such as heating with a heater so that the device itself does not become a place where the sublimate adheres.
  • a treatment such as heating with a heater
  • the melted film-like cellulose ester from the T die 4 is brought into close contact with the first cooling roll 5, the second cooling roll 7, and the third cooling roll 8 in order to be cooled and solidified, and unstretched.
  • the optical film 10 is obtained.
  • the cooled and solidified unstretched optical film 10 peeled from the third cooling roll 8 by the peeling roll 9 is stretched through a dancer roll (optical film tension adjusting roll) 11. It leads to the apparatus 12, and the optical film 10 is extended
  • a known tenter or the like can be preferably used as a method of stretching the optical film in the width direction.
  • the glass transition temperature Tg of the optical film can be controlled by varying the material type constituting the optical film and the ratio of the constituting material.
  • Tg is preferably 120 ° C. or higher, preferably 135 ° C. or higher.
  • the temperature environment of the film changes due to the temperature rise of the device itself, for example, the temperature rise derived from the light source.
  • the retardation value derived from the orientation state of the molecules fixed inside the film by stretching and the dimensional shape as the film are greatly changed.
  • Tg is preferably 250 ° C. or less.
  • known heat setting conditions, cooling, and relaxation treatment may be performed, and it may be appropriately adjusted so as to have characteristics required for the target optical film.
  • the heating and pressurizing step is performed before the stretching step and heat setting treatment.
  • the refractive index can be controlled by a stretching operation. Is a preferred method. Hereinafter, the stretching method will be described.
  • the required litter is stretched by 1.0 to 2.0 times in one direction of the cellulose resin and 1.01 to 2.5 times in the direction perpendicular to the film plane.
  • the foundation Ro and Rt can be controlled.
  • Ro indicates in-plane retardation
  • Rt indicates thickness direction retardation.
  • Retardation Ro and Rt are calculated
  • Formula (i) Ro (nx ⁇ ny) ⁇ d
  • Formula (ii) Rt ((nx + ny) / 2 ⁇ nz) ⁇ d (Where nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film (refractive index is 23 ° C., 55%) (Measured at a wavelength of 590 nm in an RH environment), d represents the thickness (nm) of the film.)
  • the refractive index of the optical film is an Abbe refractometer (4T), the thickness of the film is a commercially available micrometer, and the retardation value is an automatic birefringence meter KOBRA-21ADH (Oji Scientific Instruments) Etc.) can be used for each measurement.
  • Stretching can be performed sequentially or simultaneously, for example, in the casting direction (also referred to as MD direction) of the optical film and in the direction orthogonal to the optical film plane, that is, in the width direction (also referred to as TD direction). At this time, if the stretching ratio in at least one direction is too small, a sufficient phase difference cannot be obtained, and if it is too large, stretching becomes difficult and optical film breakage may occur.
  • the width shrinkage of the optical film can be suppressed or improved by stretching in the width direction.
  • the refractive index When stretching in the width direction, the refractive index may be distributed in the width direction. This distribution may appear when the tenter method is used.
  • a contraction force By stretching the optical film in the width direction, a contraction force is generated at the center of the optical film, and the phenomenon is caused by the end being fixed.
  • the so-called Boeing phenomenon is considered. Even in this case, by stretching in the casting direction, the bowing phenomenon can be suppressed and the distribution of the phase difference in the width direction can be reduced. Therefore, stretching in the biaxial direction of the casting direction and the width direction is preferable.
  • variation of the optical film obtained can be reduced by extending
  • unevenness of the retardation is caused, and unevenness such as coloring may be a problem when used in a liquid crystal display device.
  • the film thickness variation of the optical film is preferably in the range of ⁇ 3%, more preferably ⁇ 1%.
  • a method of stretching in the biaxial directions perpendicular to each other is effective, and the stretching ratio in the biaxial directions perpendicular to each other is finally 1.0 to 2.0 times in the casting direction.
  • the width is preferably in the range of 1.01 to 2.5 times, in the range of 1.01 to 2.0 times in the casting direction and 1.05 to 2.0 times in the width direction. It is more preferred to obtain the required retardation value.
  • the transmission axis of the polarizer matches with the width direction.
  • the retardation film is preferably stretched so as to obtain a slow axis in the width direction.
  • the slow axis of the retardation film can be imparted in the width direction by stretching in the width direction from the above configuration.
  • the slow axis of the retardation film is preferably in the width direction, and in order to obtain the desired retardation value, Formula (stretch ratio in the width direction)> (stretch ratio in the casting direction) It is necessary to satisfy the following conditions.
  • ⁇ 1 is ⁇ 1 to + 1 °, preferably ⁇ 0.5 to It is preferable that the angle is + 0.5 °.
  • each ⁇ 1 When each ⁇ 1 satisfies the above relationship, it contributes to obtaining high luminance in a display image, suppressing or preventing light leakage, and contributing to faithful color reproduction in a color liquid crystal display device.
  • the retardation film is used for the multi-domain VA mode
  • the retardation film is arranged in the above region with the fast axis of the retardation film being ⁇ 1, which contributes to the improvement of display image quality.
  • the plate and the liquid crystal display device are in the MVA mode, for example, the configuration shown in FIG. 7 can be adopted.
  • 21a and 21b are protective films
  • 22a and 22b are retardation films
  • 25a and 25b are polarizers
  • 23a and 23b are slow axis directions of the film
  • 24a and 24b are transmission axis directions of the polarizer
  • 26a Reference numeral 26b denotes a polarizing plate
  • 27 denotes a liquid crystal cell
  • 29 denotes a liquid crystal display device.
  • the retardation Ro distribution in the in-plane direction of the optical film is preferably adjusted to 5% or less, more preferably 2% or less, and particularly preferably 1.5% or less.
  • the retardation Rt distribution in the thickness direction of the film is preferably adjusted to 10% or less, more preferably 2% or less, and particularly preferably 1.5% or less.
  • the retardation value distribution fluctuation is preferably smaller, and when a polarizing plate including a retardation film is used in a liquid crystal display device, the retardation distribution fluctuation is small from the viewpoint of preventing color unevenness and the like. preferable.
  • the retardation in the thickness direction mainly compensates for the birefringence of the liquid crystal cell similarly observed when viewed from an oblique direction when the liquid crystal cell is in a black display state in the TN mode or VA mode, particularly in the MVA mode. To contribute.
  • the total value of both of the above-mentioned ranges and the thickness direction retardation Rt is larger than 140 nm and 500 nm or less.
  • the in-plane retardation Ro and the thickness direction retardation Rt of 22a and 22b are the same.
  • the in-plane retardation Ro is greater than 45 nm and not greater than 55 nm
  • the thickness direction retardation Rt is greater than 115 nm and not greater than 125 nm, and is applied to the MVA mode liquid crystal cell with the configuration of FIG. .
  • use of a film having a thickness direction retardation Rt of greater than 140 nm and not greater than 400 nm is preferable from the viewpoint of improving the display quality and producing the film.
  • the film After stretching, after slitting the edge of the optical film to a product width with a slitter 13, the film is subjected to knurling (embossing) on both ends of the film by a knurling device comprising an embossing ring 14 and a back roll 15.
  • a knurling device comprising an embossing ring 14 and a back roll 15.
  • the knurling method can process a metal ring having an uneven pattern on its side surface by heating or pressing.
  • the grip part of the clip of the both ends of a film is deform
  • the winder related to the production of the optical film of the present invention may be generally used, and it may be a winding method such as a constant tension method, a constant torque method, a taper tension method, or a program tension control method with a constant internal stress. Can be wound up.
  • the film is preferably wound under environmental conditions of a temperature of 20 to 30 ° C. and a humidity of 20 to 60% RH.
  • the tolerance of the humidity change of the thickness direction retardation (Rt) improves by prescribing
  • the humidity in the winding process of the optical film is less than 20% RH, it is not preferable because it is easily charged and cannot be put into practical use due to deterioration of the film winding quality.
  • the wound core may be any material as long as it is a cylindrical core, but is preferably a hollow plastic core, and the plastic material is heated.
  • Any heat-resistant plastic that can withstand the processing temperature may be used, and examples thereof include phenol resins, xylene resins, melamine resins, polyester resins, and epoxy resins.
  • a thermosetting resin reinforced with a filler such as glass fiber is preferred.
  • a hollow plastic core a wound core made of FRP with an outer diameter of 6 inches (hereinafter, the inch represents the number of dots of 2.54 cm) and an inner diameter of 5 inches is used.
  • the number of turns around these winding cores is preferably 100 turns or more, more preferably 500 turns or more, and the winding thickness is preferably 5 cm or more.
  • the film thickness of the optical film of the present invention varies depending on the purpose of use, but the finished optical film is preferably 10 to 500 ⁇ m.
  • the lower limit is 20 ⁇ m or more, preferably 35 ⁇ m or more.
  • the upper limit is 150 ⁇ m or less, preferably 120 ⁇ m or less.
  • a particularly preferred range is 35 to 90 ⁇ m.
  • the optical film of the present invention is a retardation film and also serves as a polarizing plate protective film
  • the film thickness of the optical film is in the above range
  • the liquid crystal display device used for a notebook computer or a mobile electronic device can be thinned and lightened. preferable.
  • the optical film is thinner than 20 ⁇ m, it is difficult to develop retardation as a retardation film, and the moisture permeability of the film is increased, and the ability to protect the polarizer from humidity is reduced. .
  • the optical film of the present invention is preferably a long film, and as the length is increased to 1500 m, 2500 m, and 5000 m, the production effect at the time of polarizing plate processing is obtained.
  • the roll length is 10 to 5000 m, preferably 50 to 4500 m in consideration of productivity and transportability.
  • the width of the optical film can be selected from the width of the polarizer and the width suitable for the production line.
  • the roll is produced by producing a film with a width of 0.5 to 4.0 m, preferably 0.6 to 3.0 m. It may be wound into a shape and subjected to polarizing plate processing. Moreover, after manufacturing the film more than the target double width and winding up to a roll, it may cut and obtain the roll of the target width, and you may make it use such a roll for polarizing plate processing.
  • compositions containing cellulose esters having different additive concentrations such as the above-mentioned plasticizer, ultraviolet absorber and matting agent.
  • an optical film having a structure of skin layer / core layer / skin layer can be produced.
  • a lot of matting agent can be contained in the skin layer or only in the skin layer.
  • Plasticizers and UV absorbers can be added more in the core layer than in the skin layer, and may be added only in the core layer.
  • the type of plasticizer and ultraviolet absorber can be changed between the core layer and the skin layer.
  • the skin layer contains a low-volatile plasticizer and / or an ultraviolet absorber, and the core layer has excellent plasticity. It is also possible to add a plasticizer or an ultraviolet absorber excellent in ultraviolet absorption.
  • the glass transition temperature of the skin layer and the core layer may be different, and the glass transition temperature of the core layer is preferably lower than the glass transition temperature of the skin layer.
  • the glass transition temperature of both the skin and the core can be measured, and the average value calculated from these volume fractions can be defined as the glass transition temperature Tg and similarly handled.
  • an antistatic layer In producing the optical film of the present invention, before and / or after stretching, an antistatic layer, a transparent conductive layer, a hard coat layer, an antireflection layer, an antifouling layer, a slippery layer, an easy adhesion layer, an antiglare layer, and a gas barrier.
  • a functional layer such as a layer or an optical compensation layer may be provided.
  • the optical film of the present invention is preferably saponified using an alkaline solution having a concentration of 2 mol / L or more as a saponification solution.
  • the saponification solution is composed of an alkali agent and water, and may optionally contain a surfactant and a compatibilizer.
  • the alkali concentration needs to be increased as the carbon number of the acyl group increases, but if the alkali concentration is too high, Since the stability of the alkaline solution is impaired and may precipitate during long-time application, it is necessary to appropriately select an alkaline solution according to the structure of the cellulose ester, but a lower alkali concentration is preferable.
  • the alkaline solution used in the present invention is preferably 2 mol / L to 4.0 mol / L, more preferably 2 mol / L to 2.5 mol / L.
  • the saponification treatment temperature is preferably 40 ° C. to 80 ° C., more preferably 40 ° C. to 70 ° C., and still more preferably 40 ° C. to 65 ° C.
  • the saponification temperature is 40 ° C. or higher, saponification of the cellulose ester surface is likely to proceed, and adhesion with a polarizer can be easily obtained, so that it becomes easy to produce a polarizing plate having good durability.
  • the saponification temperature is too high, components (such as plasticizers) in the acylate film may be extracted or decomposed, and the film may be excessively swollen. Problems may occur.
  • alkaline agents used in the present invention include sodium hydroxide, potassium, lithium, ammonium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, ammonium carbonate.
  • Inorganic alkali agents such as ammonium hydrogen carbonate, sodium borate, potassium, ammonium and the like.
  • sodium hydroxide and potassium hydroxide are preferable.
  • the reason is that the pH can be adjusted in a wide pH range by adjusting these amounts.
  • the optical film of the present invention is preferably subjected to the alkali saponification treatment by the step of saponifying the film with the alkali solution and the step of washing off the alkali solution from the film.
  • a step of neutralizing the alkaline solution and a step of washing off the neutralized solution from the film may be included.
  • steps are preferably carried out while transporting the film, and a method of immersing in an alkaline solution as described in JP-A No. 2001-188130 may be used, as described in JP-A No. 2004-203965.
  • a method of applying an alkaline solution may be used.
  • Polarizer When using the optical film of this invention as a polarizing plate protective film, the preparation methods of a polarizing plate are not specifically limited, It can manufacture by a general method.
  • the back side of the optical film of the present invention is subjected to alkali saponification treatment, and a completely saponified polyvinyl alcohol aqueous solution is used on at least one surface of a polarizer produced by immersing and stretching the treated optical film in an iodine solution. It is preferable to bond them together.
  • a commercially available optical film can be used as the polarizing plate protective film used on the other surface of the optical film of the present invention.
  • KC8UX2M, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UCR-3, KC8UCR-4, KC4FR-1, KC8UY-HA, KC8UX-RHA (above, Konica Minolta Opto) Etc. are preferably used.
  • a polarizing plate protective film that also serves as an optical compensation film having an optical anisotropic layer formed by aligning liquid crystal compounds such as discotic liquid crystal, rod-shaped liquid crystal, and cholesteric liquid crystal.
  • the optically anisotropic layer can be formed by the method described in JP-A-2003-98348.
  • a polarizer which is a main component of a polarizing plate, is an element that allows only light of a plane of polarization in a certain direction to pass.
  • a typical polarizer currently known is a polyvinyl alcohol-based polarizing film, which is polyvinyl alcohol.
  • iodine is dyed on a system film and one in which dichroic dye is dyed.
  • the stretching direction (usually the casting direction) shrinks, and the direction perpendicular to the stretching (usually the casting direction) It extends in the width direction.
  • the thickness of the polarizing plate protective film decreases, the expansion / contraction ratio of the polarizing plate increases, and in particular, the amount of contraction in the stretching direction of the polarizer increases.
  • the optical film of the present invention does not increase the wavy unevenness even in the durability test under the conditions of 60 ° C. and 90% RH, and even if it is a polarizing plate having an optical compensation film on the back side. It is possible to provide good visibility without changing the viewing angle characteristics after the test.
  • the polarizing plate is composed of a polarizer and a protective film for protecting both surfaces of the polarizer, and can further be constructed by laminating a protective film on one surface of the polarizing plate and a separate film on the opposite surface.
  • the protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection.
  • the protective film is bonded for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal plate.
  • the separate film is used for the purpose of covering the adhesive layer to be bonded to the liquid crystal plate, and is used on the surface side for bonding the polarizing plate to the liquid crystal cell.
  • a polarizing plate including a polarizing plate protective film (including a case where it also serves as a retardation film) using the optical film of the present invention can exhibit high display quality as compared with a normal polarizing plate, particularly a multi-domain type.
  • the liquid crystal display device is more suitable for use in a multi-domain liquid crystal display device, more preferably by a birefringence mode.
  • the polarizing plate of the present invention includes an MVA (Multi-domain Vertical Alignment) mode, a PVA (Patterned Vertical Alignment) mode, a CPA (Continuous Pinheal Alignment) mode, an OCB (Optical AlignSensing mode) It can be used, and is not limited to a specific liquid crystal mode and the arrangement of polarizing plates.
  • Liquid crystal display devices are being applied as devices for colorization and moving image display, and the display quality is improved by the present invention, and the improvement of contrast and the resistance of polarizing plates improve the display of moving images that are less fatigued and faithful. It becomes possible.
  • the polarizing plate including the optical film of the present invention as a retardation film and a polarizing plate protective film is disposed on the liquid crystal cell, or on the both sides of the liquid crystal cell.
  • the use of the polarizing plate so that the retardation film side faces the liquid crystal cell of the liquid crystal display device can contribute to improvement in display quality.
  • the films 22a and 22b face the liquid crystal cell of the liquid crystal display device.
  • the optical film of the present invention can optically compensate the liquid crystal cell.
  • the polarizing plate of the present invention When the polarizing plate of the present invention is used for a liquid crystal display device, at least one of the polarizing plates of the liquid crystal display device may be the polarizing plate of the present invention.
  • the polarizing plate of the present invention By using the polarizing plate of the present invention, a liquid crystal display device with improved display quality and excellent viewing angle characteristics can be provided.
  • Comparative cellulose esters 13 to 22 are synthesized in the same manner as cellulose ester 1 except that the amount of acetic acid, acetic anhydride, propionic acid, and propionic anhydride used is changed.
  • the comparative cellulose esters 23 and 24 are the same as the cellulose ester 1 except that a combination of acetic acid, acetic anhydride, butyric acid and butyric anhydride is used for the synthesis of the cellulose ester 1 and the amount used is further changed. The synthesis was performed by performing the same synthesis operation.
  • Example 1 Provide of Optical Film Containing Cellulose Ester (hereinafter simply referred to as Cellulose Ester Film) Sample F-1] As described below, the cellulose ester film F-1 of the present invention was produced by melt casting using the synthesized cellulose ester and various additives.
  • FIG. 2 a schematic flow sheet showing one embodiment of an apparatus for carrying out the method for producing an optical film of the present invention is shown in FIG. 2, and the production method will be described with reference to FIG.
  • the pellets obtained above were dried at 100 ° C. for 4 hours, then heated and melted at 250 ° C. in a nitrogen atmosphere, and then extruded from the T-type casting die 4 onto the first cooling roll 5 for the first cooling. A film was sandwiched between the roll 5 and the elastic touch roll 6 to form.
  • the first cooling roll and the second cooling roll were made of stainless steel having a diameter of 40 cm, and the surface was subjected to hard chrome plating. Further, oil for temperature adjustment was circulated inside to control the roll surface temperature.
  • the touch roll 6 having elasticity has a diameter of 20 cm
  • the inner cylinder and the outer cylinder are made of stainless steel
  • the surface of the outer cylinder is subjected to hard chrome plating.
  • the wall thickness of the outer cylinder was 2 mm, and temperature adjusting oil was circulated in the space between the inner cylinder and the outer cylinder to control the surface temperature of the touch roll 6 having elasticity.
  • the following is the same for the optical film F-2 to 12 of the present invention and the comparative optical film F- except that the cellulose ester 1 of the present invention is changed to the cellulose ester and conditions shown in Table 2 below. 13 to 24 were produced.
  • the lip clearance of the T die was changed so that the film thickness of the finished film after drawing was 40 ⁇ m.
  • plasticizer-A IRGANOX 1010, GSY-P101, Sumilizer GS, and TINUVIN 928 used in Example 1 are as follows.
  • Cellulose esters 1 to 22 are cellulose acetate propionate, and cellulose esters 23 and 24 are cellulose acetate butyrate.
  • the retardation value of the center part of the width direction of the obtained cellulose-ester film sample was measured.
  • an automatic birefringence meter KOBURA 21ADH manufactured by Oji Scientific Instruments Co., Ltd.
  • the birefringence was measured, and the measured value was substituted into the following equation.
  • d is the thickness (nm) of the film
  • the refractive index nx (the maximum refractive index in the plane of the film, also referred to as the refractive index in the slow axis direction)
  • ny the direction perpendicular to the slow axis in the film plane).
  • Refractive index of the film in the thickness direction Refractive index of the film in the thickness direction).
  • the standard deviation is 0 to less than 1 ⁇ m
  • the cellulose ester films F-1 to F-12 of the present invention have excellent retardation, small film thickness unevenness, low haze, and good adhesion to the polarizer. It turns out that it is a superior optical film.
  • the comparative cellulose ester films F-13 to F-24 cannot satisfy all of the points in terms of retardation development, film thickness uniformity, haze, and adhesion to the polarizer.
  • Example 2 The cellulose ester films F-25 to 36 of the present invention were prepared in the same manner as the cellulose ester film F-1 of Example 1, except that the cellulose ester and the combination of additives shown in Table 3 were changed to the draw ratio. Comparative cellulose ester films F-37 and 38 were produced. Further, polarizing plates P-25 to 36 of the present invention and comparative polarizing plates P-37 and 38 were produced in the same manner as the polarizing plate P-1 of Example 1. In addition, the numerical value in the bracket
  • STAB PEP-36 manufactured by ADEKA
  • ADK STAB 2112 manufactured by ADEKA
  • Example 3 (Preparation of polarizing plate) A polarizer was prepared in the same manner as in Example 1, and on one surface of the polarizer, the cellulose ester films F-1 to 12, 25 to 36 of the present invention and the comparative cellulose ester films F-13 to 24, 37, The surface treated with alkali similar to that of Example 1 in 38, and the other surface treated with the same alkali treated surface of Konica Minolta Tack KC4UY (manufactured by Konica Minolta Opto) was completely saponified.
  • a 42-type VA color liquid crystal is bonded to the Konica Minol Tack KC4UY with the liquid crystal cell sandwiched between them so that the two polarizing plates are perpendicular to each other so that the polarization axes of the polarizing plates do not change.
  • Display devices D-1 to 12, 25 to 36, and comparative liquid crystal display devices D-13 to 24, 37, and 38 were produced.
  • the measurement was performed after the backlight of each liquid crystal display device was lit continuously for one week in an environment of 23 ° C. and 55% RH.
  • EZ-Contrast 160D manufactured by ELDIM was used, the luminance from the normal direction of the display screen of white display and black display was measured with a liquid crystal display device, and the ratio was defined as the front contrast.
  • the liquid crystal display devices D-1 to 12 and 25 to 36 using the polarizing plates Q-1 to 12 and 25 to 36 of the present invention use the comparative polarizing plates Q-13 to 24, 37, and 38, respectively.

Abstract

The objective is to provide an optical film with good stretching ability, excellent realization of retardation properties, little unevenness in film thickness and good adhesiveness with a polarizer, and to provide a manufacturing method therefor. The objective is also to provide a polarizing plate that uses said optical film and has good durability over the long term, and to provide a liquid crystal display device with good durability. The optical film contains a cellulose ester with the type of substituent per glucose unit of said cellulose ester and the degree of substitution thereof that simultaneously satisfy the conditions in equations (1)-(4). Equation (1) Equation (2) Equation (3) Equation (4) [wherein X represents the degree of substitution by acetyl groups, and Y represents the degree of substitution by propionyl groups.]

Description

光学フィルム、光学フィルムの製造方法、偏光板及びそれを用いた液晶表示装置Optical film, method for producing optical film, polarizing plate and liquid crystal display device using the same
　本発明はセルロースエステルを有してなる光学フィルム、光学フィルムの製造方法、それを用いた偏光板、及び液晶表示装置に関する。 The present invention relates to an optical film comprising a cellulose ester, a method for producing the optical film, a polarizing plate using the same, and a liquid crystal display device.
　セルロースエステルを有してなる光学フィルムは、その高い透明性・低複屈折性・偏光子との易接着性などから、写真用ネガフィルムの支持体や、液晶表示装置に用いられる偏光子を保護する光学フィルムとして、偏光板などに多く用いられてきた。 Optical film made of cellulose ester protects photographic negative film supports and polarizers used in liquid crystal displays due to its high transparency, low birefringence, and easy adhesion to polarizers. As an optical film, it has been widely used for polarizing plates and the like.
　また、液晶表示装置に対するその他の用途として、位相差フィルム、視野角拡大フィルム、プラズマディスプレイに用いられる反射防止フィルム等の各種機能フィルム、更には、有機ＥＬディスプレイ等で使用される各種機能フィルム等にも利用することができる。 In addition, as other uses for liquid crystal display devices, various functional films such as retardation films, viewing angle widening films, antireflection films used in plasma displays, and various functional films used in organic EL displays, etc. Can also be used.
　液晶表示装置は、その奥行きの薄さ、軽さから近年大幅に生産量が増大しており、需要が高くなっている。 Demand for liquid crystal display devices has increased greatly in recent years due to the thinness and lightness of the liquid crystal display devices, and the demand is high.
　また液晶表示装置を用いたテレビは、薄く軽いという特徴を有し、ブラウン管を用いたテレビでは達成されなかったような大型のテレビが生産されるようになっており、それに伴って液晶表示装置を構成する偏光子、偏光板保護フィルムの需要が増大してきている。偏光板保護フィルムとしてはその光学特性の優秀さから、一般にセルロースエステルを有してなる光学フィルムが用いられている。 In addition, televisions using liquid crystal display devices are characterized by being thin and light, and large television sets that have not been achieved with televisions using cathode ray tubes have been produced. There is an increasing demand for constituent polarizers and polarizing plate protective films. As a polarizing plate protective film, an optical film having a cellulose ester is generally used because of its excellent optical properties.
　これらの光学フィルムは、これまで、専ら溶液流延法によって製造されてきた。溶液流延法とは、セルロースエステルを溶媒に溶解した溶液を流延してフィルム形状を得た後、溶媒を蒸発・乾燥させてフィルムを得るといった製膜方法である。溶液流延法で製膜したフィルムは平面性が高いため、これを用いてムラのない高画質な液晶表示装置を得ることが出来る。 These optical films have heretofore been produced exclusively by the solution casting method. The solution casting method is a film forming method in which a solution obtained by dissolving cellulose ester in a solvent is cast to obtain a film shape, and then the solvent is evaporated and dried to obtain a film. Since a film formed by the solution casting method has high flatness, a high-quality liquid crystal display device without unevenness can be obtained using the film.
　しかし溶液流延法は多量の有機溶媒を必要とし、環境負荷が大きいことも課題となっている。光学フィルムは、その溶解特性から、環境負荷の大きいハロゲン系溶媒を用いて製膜されているため、特に溶剤使用量の削減が求められており、溶液流延製膜によって光学フィルムを増産することは困難となってきている。このため、有機溶媒を使用しない製膜方法、例えば、加熱溶融により製膜方法が望まれている。 However, the solution casting method requires a large amount of an organic solvent and has a problem that the environmental load is large. Because optical films are formed using halogen-based solvents with high environmental impact due to their dissolution characteristics, reduction of solvent usage is particularly required, and production of optical films should be increased by solution casting film formation. Has become difficult. For this reason, the film forming method which does not use an organic solvent, for example, the film forming method by heat melting is desired.
　ところで、溶液流延製膜で一般に用いられているセルロースエステルであるセルローストリアセテートを溶融流延製膜に適用しようとした場合、セルローストリアセテートは分解開始温度が溶融開始温度より低いセルロースエステルであるため、溶融流延製膜に用いることは難しい。 By the way, when trying to apply cellulose triacetate, which is a cellulose ester generally used in solution casting film formation, to melt casting film formation, cellulose triacetate is a cellulose ester whose decomposition start temperature is lower than the melting start temperature, It is difficult to use for melt casting film formation.
　近年、セルロースエステルをアセチル基だけでなく特定の割合のプロピオニル基やブチリル基で置換することによって、銀塩写真用（例えば、特許文献１参照。）或いは偏光板保護フィルム用（例えば、特許文献２参照。）として、このようなセルロースエステルを溶融流延製膜する試みが行われている。このようなセルロースエステルは溶融開始温度が分解開始温度より低いため、溶融流延製膜することが可能となる。 In recent years, by substituting cellulose ester with a specific ratio of propionyl group or butyryl group in addition to acetyl group, for silver salt photography (for example, see Patent Document 1) or for polarizing plate protective film (for example, Patent Document 2). Attempts have been made to melt-cast and form such cellulose esters. Since such a cellulose ester has a melting start temperature lower than a decomposition starting temperature, it becomes possible to perform melt casting film formation.
　一方、溶融流延製膜においては、溶融時の粘度が高い状態でダイスから冷却ドラムにキャストするためフィルムのレベリングが悪く、溶液流延製膜に比べ位相差（リターデーション）のばらつきが発生し光学特性に劣るという課題があったが、特定の置換度を有するセルロースアセテートプロピオネートを用いることにより溶融流延製膜を用いてもリターデーションのばらつきを低減させることが可能となった（特許文献３参照。）。 On the other hand, in melt casting film formation, casting is cast from a die to a cooling drum in a state where the viscosity at the time of melting is high, so that the leveling of the film is poor, and variation in retardation (retardation) occurs compared to solution casting film formation. Although there was a problem of inferior optical properties, it became possible to reduce variation in retardation even when using melt casting film formation by using cellulose acetate propionate having a specific substitution degree (patent) Reference 3).
　液晶表示装置の視野角拡大もしくはコントラスト向上を実現するために、位相差フィルムが用いられている。近年、セルロースエステルフィルムを延伸することにより位相差を発現させ、これをケン化処理して偏光子と貼り合わせ、位相差フィルムの機能を併せ持つ偏光板保護フィルムが実現されている（例えば、特許文献４参照。）。この方式は、従来の偏光板に位相差フィルムを貼合するものと比べ、工程数及び部品点数が少なく大幅なコストダウンが達成されるものである。 A phase difference film is used to increase the viewing angle or improve the contrast of a liquid crystal display device. In recent years, retardation films have been developed by stretching a cellulose ester film, saponified and bonded to a polarizer, and a polarizing plate protective film having a retardation film function has been realized (for example, Patent Documents). 4). In this method, the number of steps and the number of parts are small and a significant cost reduction is achieved as compared with the case where a retardation film is bonded to a conventional polarizing plate.
　上記の位相差フィルムは延伸してリターデーションを発現させるが、生産性の向上のためには幅手（ＴＤ）方向のみならず、長手（ＭＤ）方向に、所謂二軸延伸するのが好ましい。しかしながら、従来公知の溶融流延製膜においては、生産性向上とリターデーションの発現を同時に達成させるために二軸方向に高倍率に延伸すると、膜厚ムラが生じ易くなる上、ヘイズが上昇し、偏光子との密着性が劣化することが分かった。また、この位相差フィルムを用いて作製した液晶表示装置は視野角とコントラストの劣化が生じるという課題があった。 The retardation film described above is stretched to develop retardation. However, in order to improve productivity, it is preferable to perform so-called biaxial stretching not only in the width (TD) direction but also in the longitudinal (MD) direction. However, in the conventionally known melt casting film formation, when stretching at a high magnification in the biaxial direction in order to achieve productivity improvement and expression of retardation at the same time, film thickness unevenness is liable to occur and haze increases. It was found that the adhesion with the polarizer deteriorates. Moreover, the liquid crystal display device produced using this retardation film had the subject that viewing angle and contrast deteriorated.
　従って、溶液流延法によって製膜されたトリアセチルセルロースフィルムに代わり、優れた環境適性を有し、品質及び生産性の共に良好な溶融流延製膜されたセルロースエステルを有してなる光学フィルム、該光学フィルムの製造方法、ひいてはそれを用いた偏光板及び液晶表示装置の出現が待たれている状況にある。 Therefore, in place of the triacetyl cellulose film formed by the solution casting method, an optical film having a cellulose ester formed by melt casting having excellent environmental suitability and good quality and productivity. The production method of the optical film, and hence the appearance of a polarizing plate and a liquid crystal display device using the method, are awaited.
特表平６－５０１０４０号公報Japanese National Patent Publication No. 6-501040 特開２０００－３５２６２０号公報JP 2000-352620 A 国際公開第２００８／６８９６１号パンフレットInternational Publication No. 2008/68961 Pamphlet 特開２００３－２７０４４２号公報JP 2003-270442 A
　本発明は、上記問題に鑑みなされたものであり、本発明の目的は、環境適性に優れ、製膜性が良好で、光学特性に優れた光学フィルム、より詳しくは、延伸適性が良好で、リターデーションの発現性に優れ、膜厚ムラが小さく、ヘイズが低く、かつ偏光子との密着性が良好な光学フィルム、及びその製造方法を提供することにある。更には、該光学フィルムを用いて長期にわたって耐久性が良好な偏光板及び視野角が広く耐久性の良好な液晶表示装置を提供することにある。 The present invention has been made in view of the above problems, and the object of the present invention is an optical film having excellent environmental suitability, good film forming properties and excellent optical properties, more specifically, good stretchability, An object of the present invention is to provide an optical film excellent in retardation development, small film thickness unevenness, low haze, and good adhesion to a polarizer, and a method for producing the same. Furthermore, another object of the present invention is to provide a polarizing plate having good durability over a long period of time and a liquid crystal display device having a wide viewing angle and good durability using the optical film.
　本発明の上記目的は以下の構成により達成される。 The above object of the present invention is achieved by the following configuration.
　１．光学フィルムがセルロースエステルを含有し、該セルロースエステルの１グルコース単位あたりの置換基の種類とその置換度が下記式（１）～（４）の条件を同時に満たすセルロースエステルであることを特徴とする光学フィルム。 1. The optical film contains a cellulose ester, and the cellulose ester satisfies the conditions of the following formulas (1) to (4) at the same time as the type of substituent and the degree of substitution per glucose unit of the cellulose ester. Optical film.
　式（１）　６．３０≦２×Ｘ＋３×Ｙ≦６．８０
　式（２）　２．３５≦Ｘ＋Ｙ≦２．５５
　式（３）　０．７０≦Ｘ≦１．１０
　式（４）　１．４５≦Ｙ≦１．７５
〔式中、Ｘはアセチル基による置換度を表し、Ｙはプロピオニル基による置換度を表す。〕
　２．前記セルロースエステルの重量平均分子量（Ｍｗ）が１５万～２５万であることを特徴とする前記１に記載の光学フィルム。 Formula (1) 6.30 ≦ 2 × X + 3 × Y ≦ 6.80
Formula (2) 2.35 ≦ X + Y ≦ 2.55
Formula (3) 0.70 <= X <= 1.10
Formula (4) 1.45 ≦ Y ≦ 1.75
[Wherein, X represents the degree of substitution with an acetyl group, and Y represents the degree of substitution with a propionyl group. ]
2. 2. The optical film as described in 1 above, wherein the cellulose ester has a weight average molecular weight (Mw) of 150,000 to 250,000.
　３．多価アルコールエステル系化合物を含むことを特徴とする前記１または２に記載の光学フィルム。 3. 3. The optical film as described in 1 or 2 above, comprising a polyhydric alcohol ester compound.
　４．炭水化物エステル系化合物を含むことを特徴とする前記１～３のいずれか１項に記載の光学フィルム。 4. 4. The optical film as described in any one of 1 to 3 above, which comprises a carbohydrate ester compound.
　５．ヒンダードフェノール系化合物を含むことを特徴とする前記１～４のいずれか１項に記載の光学フィルム。 5. 5. The optical film as described in any one of 1 to 4 above, which comprises a hindered phenol compound.
　６．ホスファイト系化合物またはホスホナイト系化合物を含むことを特徴とする前記１～５のいずれか１項に記載の光学フィルム。 6. 6. The optical film as described in any one of 1 to 5 above, which comprises a phosphite compound or a phosphonite compound.
　７．位相差フィルムであることを特徴とする前記１～６のいずれか１項に記載の光学フィルム。 7. 7. The optical film as described in any one of 1 to 6 above, which is a retardation film.
　８．前記１～７のいずれか１項に記載の光学フィルムを溶融流延法によって製造することを特徴とする光学フィルムの製造方法。 8. 8. A method for producing an optical film, wherein the optical film according to any one of 1 to 7 is produced by a melt casting method.
　９．溶融流延の後、得られたフィルムを延伸する工程を含むことを特徴とする前記７に記載の光学フィルムの製造方法。 9. 8. The method for producing an optical film as described in 7 above, which comprises a step of stretching the obtained film after melt casting.
　１０．延伸する工程が二軸方向に延伸する工程であることを特徴とする前記９に記載の光学フィルムの製造方法。 10. 10. The method for producing an optical film as described in 9 above, wherein the stretching step is a biaxial stretching step.
　１１．前記１～７のいずれか１項に記載の光学フィルムまたは前記８～１０のいずれか１項に記載の製造方法により製造された光学フィルムを偏光子の少なくとも一方の面に有することを特徴とする偏光板。 11. The optical film according to any one of 1 to 7 or the optical film produced by the production method according to any one of 8 to 10 is provided on at least one surface of a polarizer. Polarizer.
　１２．前記１１に記載の偏光板を液晶セルの少なくとも一方の面に用いることを特徴とする液晶表示装置。 12. 12. A liquid crystal display device using the polarizing plate according to 11 above on at least one surface of a liquid crystal cell.
　１３．液晶セルがＶＡ型液晶セルであることを特徴とする前記１２に記載の液晶表示装置。 13. 13. The liquid crystal display device as described in 12 above, wherein the liquid crystal cell is a VA liquid crystal cell.
　即ち、本発明者らは、上記の課題解決のために鋭意検討する過程において、セルロースエステルを構成する１グルコース単位あたりの置換基の種類とその置換度が本発明の構成範囲である場合、上記の課題がすべて解決できること見出し、本発明を完成するに至った。 That is, the present inventors, in the process of intensively studying to solve the above problems, when the type of substituent per glucose unit constituting the cellulose ester and the degree of substitution are within the scope of the present invention, The present inventors have found that all the above problems can be solved and have completed the present invention.
　本発明により、環境適性に優れ、製膜性が良好で、光学特性に優れた光学フィルム、より詳しくは、延伸適性が良好で、リターデーションの発現性に優れ、膜厚ムラが小さく、ヘイズが低く、かつ偏光子との密着性が良好な光学フィルム、及びその製造方法を提供することができた。更には、該光学フィルムを用いて長期にわたって耐久性が良好な偏光板及び視野角が広く耐久性の良好な液晶表示装置を提供することができた。 According to the present invention, an optical film having excellent environmental suitability, good film forming properties, and excellent optical properties, more specifically, good stretchability, excellent retardation development, small film thickness unevenness, and haze It was possible to provide an optical film that is low and has good adhesion to a polarizer, and a method for producing the same. Furthermore, it was possible to provide a polarizing plate having good durability over a long period of time and a liquid crystal display device having a wide viewing angle and good durability using the optical film.
本発明に係るセルロースエステルフィルムの製造方法を実施する装置の１つの実施形態を示す概略フローシートである。It is a general | schematic flow sheet which shows one embodiment of the apparatus which enforces the manufacturing method of the cellulose-ester film which concerns on this invention. 図１の製造装置の要部拡大フローシートである。It is a principal part expansion flow sheet of the manufacturing apparatus of FIG. 図３（ａ）は流延ダイの要部の外観図、図３（ｂ）は流延ダイの要部の断面図である。3A is an external view of the main part of the casting die, and FIG. 3B is a cross-sectional view of the main part of the casting die. 挟圧回転体の第１実施形態の断面図である。It is sectional drawing of 1st Embodiment of a pinching rotary body. 挟圧回転体の第２実施形態の回転軸に垂直な平面での断面図である。It is sectional drawing in the plane perpendicular | vertical to the rotating shaft of 2nd Embodiment of a pinching rotary body. 挟圧回転体の第２実施形態の回転軸を含む平面での断面図である。It is sectional drawing in the plane containing the rotating shaft of 2nd Embodiment of a pinching rotary body. 液晶表示装置の構成図の概略を示す分解斜視図である。It is a disassembled perspective view which shows the outline of the block diagram of a liquid crystal display device.
　以下、本発明を実施するための最良の形態について詳細に説明するが、本発明はこれらに限定されるものではない。 Hereinafter, the best mode for carrying out the present invention will be described in detail, but the present invention is not limited thereto.
　本発明は、生産性が良好で、光学特性に優れた光学フィルムを提供するものである。このような光学フィルムを用いることで、高品質の偏光板保護フィルム、位相差フィルム、反射防止フィルム等の光学フィルムを得ることが出来、さらには表示品質の高い液晶表示装置を得ることが出来る。 The present invention provides an optical film with good productivity and excellent optical properties. By using such an optical film, it is possible to obtain optical films such as a high-quality polarizing plate protective film, a retardation film, and an antireflection film, and it is possible to obtain a liquid crystal display device with high display quality.
　本発明の光学フィルムは、溶液流延法、溶融流延法のどちらによって製造された光学フィルムでもよいが、環境適性に鑑みると溶融流延法であることが好ましい。本発明において、溶液流延のように光学フィルムを溶媒に溶解させることなしに、該光学フィルム形成材料を加熱することにより流動可能な溶融状態とし、流延することを溶融流延法として定義する。 The optical film of the present invention may be an optical film produced by either a solution casting method or a melt casting method, but in view of environmental suitability, the melt casting method is preferred. In the present invention, the optical film forming material is heated to a molten state without dissolving the optical film in a solvent as in solution casting, and casting is defined as a melt casting method. .
　加熱溶融する成形法は、更に詳細には、溶融押出成形法、プレス成形法、インフレーション法、射出成形法、ブロー成形法、延伸成形法などに分類できる。これらの中で、機械的強度及び表面精度などに優れる光学フィルムを得るためには、溶融押出し法が優れている。 The molding method for heating and melting can be further classified into a melt extrusion molding method, a press molding method, an inflation method, an injection molding method, a blow molding method, a stretch molding method, and the like. Among these, in order to obtain an optical film excellent in mechanical strength and surface accuracy, the melt extrusion method is excellent.
　本発明において、光学フィルム形成材料が加熱されて、その流動性を発現させた後ドラム上またはエンドレスベルト上に押出し製膜する方法が、本発明の溶融流延法として好ましい態様である。 In the present invention, a method in which the optical film forming material is heated to develop its fluidity and then extruded and formed on a drum or an endless belt is a preferred embodiment as the melt casting method of the present invention.
　従って本発明の光学フィルムは、少なくとも１種の下記に示すセルロースエステルを含む光学フィルム形成材料を、好ましくは２００℃以上２７０℃以下の溶融温度にて加熱溶融し、溶融流延法により形成された光学フィルムであることが特に好ましい。 Accordingly, the optical film of the present invention is formed by melt-casting an optical film-forming material containing at least one of the following cellulose esters, preferably at a melting temperature of 200 ° C. or higher and 270 ° C. or lower. An optical film is particularly preferable.
　以下、本発明の光学フィルムについて説明する。 Hereinafter, the optical film of the present invention will be described.
　《セルロースエステル》
　本発明に用いるセルロースエステルは、アセチル基の置換度をＸとし、プロピオニル基の置換度をＹとしたとき、下記式（１）～（４）を同時に満たすセルロースエステルである。このようなセルロースエステルは、通常、セルロースアセテートプロピオネートと呼ばれる。なお、下記式の何れか一つ、何れか二つ、あるいは何れか三つを満たしているだけでは上記課題のすべての解決にはならず、四つすべてを同時に満たすことが重要である。 《Cellulose ester》
The cellulose ester used in the present invention is a cellulose ester that simultaneously satisfies the following formulas (1) to (4) when the substitution degree of the acetyl group is X and the substitution degree of the propionyl group is Y. Such cellulose esters are usually called cellulose acetate propionate. Note that satisfying any one, any two, or any three of the following formulas does not solve all of the above problems, but it is important to satisfy all four simultaneously.
　式（１）　６．３０≦２×Ｘ＋３×Ｙ≦６．８０
　式（２）　２．３５≦Ｘ＋Ｙ≦２．５５
　式（３）　０．７０≦Ｘ≦１．１０
　式（４）　１．４５≦Ｙ≦１．７５
　中でも、式（１）においては６．４０≦２×Ｘ＋３×Ｙ≦６．７０とするのが、本発明の効果をより奏する点で好ましい。式（２）においては２．４０≦Ｘ＋Ｙ≦２．５０とするのが、本発明の効果をより奏する点で好ましい。式（３）においては０．７５≦Ｘ≦１．０５とするのが本発明の効果をより奏する点で好ましい。式（４）においては１．５０≦Ｙ≦１．７５とするのが本発明の効果をより奏する点で好ましい。 Formula (1) 6.30 ≦ 2 × X + 3 × Y ≦ 6.80
Formula (2) 2.35 ≦ X + Y ≦ 2.55
Formula (3) 0.70 <= X <= 1.10
Formula (4) 1.45 ≦ Y ≦ 1.75
Among them, in the formula (1), it is preferable that 6.40 ≦ 2 × X + 3 × Y ≦ 6.70 from the viewpoint that the effect of the present invention is further achieved. In the formula (2), it is preferable that 2.40 ≦ X + Y ≦ 2.50 because the effects of the present invention are further exhibited. In the formula (3), it is preferable that 0.75 ≦ X ≦ 1.05 from the viewpoint that the effect of the present invention is further exhibited. In the formula (4), it is preferable that 1.50 ≦ Y ≦ 1.75 because the effects of the present invention are further exhibited.
　次に、本発明に用いられるセルロースエステルのアシル基（アセチル基とプロピオニル基）の置換度について詳細に説明する。 Next, the substitution degree of the acyl groups (acetyl group and propionyl group) of the cellulose ester used in the present invention will be described in detail.
　セルロースには、１グルコース単位の２位、３位、６位に１個ずつ、計３個の水酸基があり、総置換度とは、平均して１グルコース単位にいくつのアシル基が結合しているかを示す数値である。従って、最大の置換度は３．００であり、上記アシル基で置換されていない部分は通常水酸基として存在しているものである。２位と３位は２級の水酸基、６位は１級の水酸基であり、アセチル基とプロピオニル基がそれぞれどの位置をどのような割合で置換するかによってセルロースエステルの高次構造や物性に変化を伴う。このようなセルロースの水酸基の一部またはすべてがアシル基で置換されたものをセルロースエステルと称している。 Cellulose has a total of three hydroxyl groups, one at each of the 2nd, 3rd and 6th positions of 1 glucose unit. The total degree of substitution is the average number of acyl groups bonded to 1 glucose unit. It is a numerical value indicating whether or not. Accordingly, the maximum degree of substitution is 3.00, and the portion not substituted with the acyl group is usually present as a hydroxyl group. The 2nd and 3rd positions are secondary hydroxyl groups, and the 6th position is a primary hydroxyl group, which changes to the higher order structure and physical properties of the cellulose ester depending on which position the acetyl group and propionyl group are substituted in. Accompanied by. A cellulose ester in which some or all of the hydroxyl groups of cellulose are substituted with acyl groups is referred to as a cellulose ester.
　本発明のセルロースエステルは、２位、３位、及び６位のアセチル基による平均置換度の合計をＸとし、２位、３位、及び６位のプロピオニル基による平均置換度の合計をＹとしたときに、前記式（１）～（４）を同時に満たすセルロースエステルである（平均置換度を単に置換度と称する。）。なお、アセチル基とプロピオニル基の置換度は、ＡＳＴＭ　Ｄ８１７－９６に規定の方法により求めたものである。 In the cellulose ester of the present invention, X is the sum of the average degree of substitution by the 2-, 3-, and 6-position acetyl groups, and Y is the sum of the average degree of substitution by the 2-, 3-, and 6-position propionyl groups. The cellulose ester satisfying the above formulas (1) to (4) simultaneously (the average degree of substitution is simply referred to as the degree of substitution). The degree of substitution between the acetyl group and the propionyl group was determined by the method prescribed in ASTM D817-96.
　式（１）について説明すると、式（１）はセルロースエステルの１グルコース単位あたりに置換されたアシル基の平均の総炭素数の範囲を表している。つまり、アセチル基の炭素数は２、プロピオニル基の炭素数は３となるため、それぞれの置換度を掛けた「２×Ｘ＋３×Ｙ」が総炭素数となる。本発明者の検討で、総炭素数が小さいと親水性が高く、偏光子との密着性が高い反面、溶融製膜性に劣り、逆に総炭素数が大きいと疎水性が高く、溶融製膜性に優れる反面、偏光子との密着性が低いことが判明した。 Describing the formula (1), the formula (1) represents the range of the average total carbon number of the acyl group substituted per glucose unit of the cellulose ester. That is, since the carbon number of the acetyl group is 2 and the carbon number of the propionyl group is 3, “2 × X + 3 × Y” multiplied by the respective substitution degrees is the total carbon number. According to the inventor's study, if the total number of carbons is small, the hydrophilicity is high and the adhesion to the polarizer is high, but on the other hand, it is inferior in melt film-forming properties. While it was excellent in film properties, it was found that the adhesion to the polarizer was low.
　式（２）について説明すると、式（２）はセルロースエステルの１グルコース単位あたりに置換されたアシル基の平均の総置換度（Ｘ＋Ｙ）の範囲を表している。本発明者の検討で、総置換度が小さいとリターデーションが発現しやすい反面、延伸した時にヘイズが高くなりやすく、逆に総置換度が大きいと延伸した時のヘイズは低いが、リターデーションが発現しにくいことが判明した。 Describing the formula (2), the formula (2) represents the range of the average total degree of substitution (X + Y) of acyl groups substituted per glucose unit of the cellulose ester. In the study of the present inventor, retardation is likely to be manifested when the total degree of substitution is small, whereas the haze tends to be high when stretched, and conversely, when the total degree of substitution is large, the haze when stretched is low, but the retardation is low. It was found that it was difficult to express.
　式（３）のアセチル基の置換度、式（４）のプロピオニル基の置換度に関しても、偏光子との密着性、溶融製膜性、リターデーションの発現性、ヘイズに影響があることが本発明者の検討により判明した。 The degree of substitution of the acetyl group of the formula (3) and the degree of substitution of the propionyl group of the formula (4) also have an influence on adhesion to the polarizer, melt film-forming property, expression of retardation, and haze. It became clear by examination of the inventor.
　今回、鋭意検討した結果、驚くべきことに前記式（１）～（４）の条件を同時に満たすセルロースエステルを有してなる光学フィルムに限り、本発明の課題のすべてを満足することができることが判明し、本発明に至った次第である。 As a result of intensive studies, it is surprising that all the problems of the present invention can be satisfied as long as the optical film has a cellulose ester that simultaneously satisfies the conditions of the above formulas (1) to (4). It is ascertained and the present invention has been reached.
　本発明に用いられるセルロースエステルは、特に限定はないが、１５万～２５万の重量平均分子量（Ｍｗ）を有することが好ましく、１８万～２３万の重量平均分子量を有することが更に好ましく、１９万～２２万の重量平均分子量を有することが最も好ましい。 The cellulose ester used in the present invention is not particularly limited, but preferably has a weight average molecular weight (Mw) of 150,000 to 250,000, more preferably has a weight average molecular weight of 180,000 to 230,000, Most preferably, it has a weight average molecular weight of 10,000 to 220,000.
　重量平均分子量が上記好ましい範囲内においては、溶融粘度が高くなりすぎたり、得られるフィルムの強度が低下したりするなどの不具合が生じず、好ましい。 When the weight average molecular weight is within the above preferred range, it does not cause problems such as an excessively high melt viscosity or reduced strength of the resulting film, which is preferable.
　更に、本発明に用いられるセルロースエステルは、重量平均分子量（Ｍｗ）／数平均分子量（Ｍｎ）比が１．３～５．５のものが好ましく用いられ、特に好ましくは１．５～５．０であり、更に好ましくは１．７～４．０であり、更に好ましくは２．０～３．５のセルロースエステルが好ましく用いられる。Ｍｗ／Ｍｎが５．５を超えると、粘度が高くなり、溶融製膜性が低下する傾向があり好ましくない。一方、工業上の製造特性の点から、１．３以上であることが好ましい。 Further, the cellulose ester used in the present invention preferably has a weight average molecular weight (Mw) / number average molecular weight (Mn) ratio of 1.3 to 5.5, particularly preferably 1.5 to 5.0. More preferably, it is 1.7 to 4.0, and more preferably 2.0 to 3.5 cellulose ester is preferably used. When Mw / Mn exceeds 5.5, the viscosity becomes high and the melt film-forming property tends to decrease, which is not preferable. On the other hand, from the viewpoint of industrial production characteristics, it is preferably 1.3 or more.
　なお、Ｍｎ及びＭｗ／Ｍｎは下記の要領で、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）により算出できる。 Mn and Mw / Mn can be calculated by gel permeation chromatography (GPC) in the following manner.
　測定条件は以下の通りである。 The measurement conditions are as follows.
　溶媒　　　：テトヒドロフラン
　装置　　　：ＨＬＣ－８２２０（東ソー（株）製）
　カラム　　：ＴＳＫｇｅｌ　ＳｕｐｅｒＨＭ－Ｍ（東ソー（株）製）
　カラム温度：４０℃
　試料濃度　：０．１質量％
　注入量　　：１０μｌ
　流量　　　：０．６ｍｌ／ｍｉｎ
　校正曲線　：標準ポリスチレン：ＰＳ－１（Ｐｏｌｙｍｅｒ　Ｌａｂｏｒａｔｏｒｉｅｓ社製）Ｍｗ＝２，５６０，０００～５８０までの９サンプルによる校正曲線を使用した。 Solvent: Tetohydrofuran Equipment: HLC-8220 (manufactured by Tosoh Corporation)
Column: TSKgel SuperHM-M (manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Sample concentration: 0.1% by mass
Injection volume: 10 μl
Flow rate: 0.6 ml / min
Calibration curve: Standard polystyrene: PS-1 (manufactured by Polymer Laboratories) Mw = 2, 560,000 to 580, a calibration curve with 9 samples was used.
　フィルム形成材料中のセルロースエステルは７０質量％～９９質量％の範囲とすることが好ましく、後述する劣化防止剤、可塑剤および紫外線吸収剤等の添加剤の存在下で優れた溶融流延性と安定性を示し、得られたフィルムは光学フィルムとしての優れた性能を付与することができる。セルロースエステルの含有量が７０質量％以下であると、添加剤がブリードアウトしたり、フィルムの機械強度が小さくなってしまったりするために好ましくない。また光学フィルムとして必要な他の添加剤の添加量が１．０質量％以下であると（セルロースエステルの含有量が９９％以上であると）、要求される物性を満たすことが難しい。より好ましくはセルロースエステルの含有量は８０～９５質量％である。 The cellulose ester in the film-forming material is preferably in the range of 70% by mass to 99% by mass, and has excellent melt castability and stability in the presence of additives such as deterioration inhibitors, plasticizers and ultraviolet absorbers described later. The obtained film can impart excellent performance as an optical film. When the content of the cellulose ester is 70% by mass or less, the additive bleeds out and the mechanical strength of the film becomes small, which is not preferable. Further, when the amount of other additives necessary as an optical film is 1.0% by mass or less (the content of cellulose ester is 99% or more), it is difficult to satisfy the required physical properties. More preferably, the cellulose ester content is 80 to 95% by mass.
　本発明で用いられるセルロースエステルの原料セルロースは、木材パルプでも綿花リンターでもよく、木材パルプは針葉樹でも広葉樹でもよいが、針葉樹の方がより好ましい。製膜の際の剥離性の点からは綿花リンターが好ましく用いられる。これらから作られたセルロースエステルは適宜混合して、或いは単独で使用することができる。 The raw material cellulose of the cellulose ester used in the present invention may be wood pulp or cotton linter, and the wood pulp may be softwood or hardwood, but softwood is more preferable. A cotton linter is preferably used from the viewpoint of peelability during film formation. The cellulose ester made from these can be mixed suitably or can be used independently.
　例えば、綿花リンター由来セルロースエステル：木材パルプ（針葉樹）由来セルロースエステル：木材パルプ（広葉樹）由来セルロースエステルの比率が１００：０：０、９０：１０：０、８５：１５：０、５０：５０：０、２０：８０：０、１０：９０：０、０：１００：０、０：０：１００、８０：１０：１０、８５：０：１５、４０：３０：３０で用いることができる。 For example, the ratio of cellulose ester derived from cellulose linter: cellulose ester derived from wood pulp (coniferous): cellulose ester derived from wood pulp (hardwood) is 100: 0: 0, 90: 10: 0, 85: 15: 0, 50:50: 0, 20: 80: 0, 10: 90: 0, 0: 100: 0, 0: 0: 100, 80:10:10, 85: 0: 15, 40:30:30.
　本発明のセルロースエステルは、公知の方法を参考にして合成することができる。例えば、原料セルロースの水酸基を無水酢酸、及び無水プロピオン酸を用いて常法によりアセチル化、及びプロピオニル化し、アセチル基、プロピオニル基を置換させることができる。このようなセルロースエステルの合成方法は、特に限定はないが、例えば、特開平１０－４５８０４号或いは特表平６－５０１０４０号に記載の方法を参考にして合成することができる。なお、用いる無水酢酸、及び無水プロピオン酸の使用量を適宜変化させることによって、前記式（１）～（４）を同時に満たすセルロースエステルを合成することができる。 The cellulose ester of the present invention can be synthesized with reference to known methods. For example, the acetyl group and propionyl group can be substituted by acetylating and propionating the hydroxyl group of the raw material cellulose by acetic anhydride and propionic anhydride by a conventional method. The method for synthesizing such a cellulose ester is not particularly limited, and for example, it can be synthesized with reference to the method described in JP-A-10-45804 or JP-A-6-501040. It should be noted that a cellulose ester that simultaneously satisfies the above formulas (1) to (4) can be synthesized by appropriately changing the amounts of acetic anhydride and propionic anhydride used.
　本発明に用いられるセルロースエステルのアルカリ土類金属含有量は、１～５０ｐｐｍの範囲であることが好ましい。５０ｐｐｍを超えるとリップ付着汚れが増加或いは熱延伸時や熱延伸後でのスリッティング部で破断しやすくなる。１ｐｐｍ未満でも破断しやすくなるがその理由はよく分かっていない。更に１～３０ｐｐｍの範囲が好ましい。ここでいうアルカリ土類金属とはＣａ、Ｍｇの総含有量のことであり、Ｘ線光電子分光分析装置（ＸＰＳ）を用いて測定することができる。 The alkaline earth metal content of the cellulose ester used in the present invention is preferably in the range of 1 to 50 ppm. If it exceeds 50 ppm, lip adhesion stains increase or breakage tends to occur at the slitting part during or after hot stretching. Even if it is less than 1 ppm, it tends to break, but the reason is not well understood. Further, the range of 1 to 30 ppm is preferable. The alkaline earth metal as used herein refers to the total content of Ca and Mg, and can be measured using an X-ray photoelectron spectrometer (XPS).
　本発明に用いられるセルロースエステル中の残留硫酸含有量は、硫黄元素換算で０．１～４５ｐｐｍの範囲であることが好ましい。これらは塩の形で含有していると考えられる。残留硫酸含有量が４５ｐｐｍを超えると熱溶融時のダイリップ部の付着物が増加するため好ましくない。また、熱延伸時や熱延伸後でのスリッティングの際に破断しやすくなるため好ましくない。少ない方が好ましいが、０．１未満とすると、逆に破断しやすくなることがあり好ましくないが、その理由はよく分かっていない。更に１～３０ｐｐｍの範囲が好ましい。残留硫酸含有量は、ＡＳＴＭ　Ｄ８１７－９６に規定の方法により測定することができる。 The residual sulfuric acid content in the cellulose ester used in the present invention is preferably in the range of 0.1 to 45 ppm in terms of elemental sulfur. These are considered to be contained in the form of salts. If the residual sulfuric acid content exceeds 45 ppm, the deposits on the die lip during heat melting increase, such being undesirable. Moreover, since it becomes easy to fracture | rupture at the time of slitting at the time of hot drawing or after hot drawing, it is not preferable. Less is preferable, but if it is less than 0.1, it tends to break on the contrary, it is not preferable, but the reason is not well understood. Further, the range of 1 to 30 ppm is preferable. The residual sulfuric acid content can be measured by the method prescribed in ASTM D817-96.
　本発明に用いられるセルロースエステル中の遊離酸含有量は、１～５００ｐｐｍであることが好ましい。５００ｐｐｍを超えるとダイリップ部の付着物が増加し、また破断しやすくなる。更に１～１００ｐｐｍの範囲であることが好ましく、更に破断しにくくなる。特に１～７０ｐｐｍの範囲が好ましい。遊離酸含有量はＡＳＴＭ　Ｄ８１７－９６に規定の方法により測定することができる。 The free acid content in the cellulose ester used in the present invention is preferably 1 to 500 ppm. If it exceeds 500 ppm, deposits on the die lip will increase and breakage will easily occur. Further, it is preferably in the range of 1 to 100 ppm, and it becomes more difficult to break. The range of 1 to 70 ppm is particularly preferable. The free acid content can be measured by the method prescribed in ASTM D817-96.
　合成したセルロースエステルの洗浄を、溶液流延法に用いられる場合に比べて、更に十分に行うことによって、残留アルカリ土類金属含有量、残留硫酸含有量、及び残留酸含有量を上記の範囲とすることができ好ましい。また、セルロースエステルの洗浄は、水に加えて、メタノール、エタノールのような貧溶媒、或いは結果として貧溶媒であれば貧溶媒と良溶媒の混合溶媒を用いることができ、残留酸以外の無機物、低分子の有機不純物を除去することができる。更に、セルロースエステルの洗浄は、劣化防止剤の存在下で行うことも好ましく、セルロースエステルの耐熱性、製膜安定性が向上する。使用される劣化防止剤は、セルロースエステルに発生したラジカルを不活性化する、或いはセルロースエステルに発生したラジカルに酸素が付加したことが起因のセルロースエステルの劣化を抑制する化合物であれば制限なく用いることができる。 By washing the synthesized cellulose ester more sufficiently than when used in the solution casting method, the residual alkaline earth metal content, residual sulfuric acid content, and residual acid content are within the above ranges. This is preferable. In addition to washing with water, cellulose ester can be washed with a poor solvent such as methanol or ethanol, or as a result, a mixed solvent of a poor solvent and a good solvent can be used as a poor solvent. Low molecular organic impurities can be removed. Further, the washing of the cellulose ester is also preferably performed in the presence of a deterioration inhibitor, and the heat resistance and film forming stability of the cellulose ester are improved. The deterioration preventing agent used is not limited as long as it is a compound that inactivates radicals generated in the cellulose ester or suppresses deterioration of the cellulose ester caused by addition of oxygen to the radical generated in the cellulose ester. be able to.
　また、セルロースエステルの耐熱性、機械特性、光学特性等を向上させるため、セルロースエステルの良溶媒に溶解後、貧溶媒中に再沈殿、濾過することによって、或いは、貧溶媒中に撹拌懸濁させ、濾過することによって、セルロースエステルの低分子量成分、その他不純物を除去することができる。この時、前述のセルロースエステルの洗浄同様に、劣化防止剤の存在下で行うことが好ましい。 In order to improve the heat resistance, mechanical properties, optical properties, etc. of cellulose ester, dissolve it in a good solvent of cellulose ester, reprecipitate it in a poor solvent, filter it, or stir and suspend it in the poor solvent. The low molecular weight component of cellulose ester and other impurities can be removed by filtration. At this time, it is preferable to carry out in the presence of a deterioration preventing agent, similarly to the above-described washing of the cellulose ester.
　セルロースエステルの洗浄に使用する劣化防止剤は、洗浄後セルロースエステル中に残存していてもよい。残存量は０．０１～２０００ｐｐｍがよく、より好ましくは０．０５～１０００ｐｐｍである。更に好ましくは０．１～１００ｐｐｍである。 The deterioration inhibitor used for washing the cellulose ester may remain in the cellulose ester after washing. The residual amount is preferably 0.01 to 2000 ppm, more preferably 0.05 to 1000 ppm. More preferably, it is 0.1 to 100 ppm.
　更に、セルロースエステルの再沈殿処理の後、別のポリマー或いは低分子化合物を添加してもよい。 Furthermore, another polymer or a low molecular weight compound may be added after the reprecipitation treatment of the cellulose ester.
　また、本発明で用いられるセルロースエステルはフィルムにした時の輝点異物が少ないものであることが好ましい。輝点異物とは、２枚の偏光板を直交に配置し（クロスニコル）、この間にセルロースエステルフィルムを配置して、一方の面から光源の光を当てて、もう一方の面からセルロースエステルフィルムを観察した時に、光源の光が漏れて見える点のことである。このとき評価に用いる偏光板は輝点異物がない保護フィルムで構成されたものであることが望ましく、偏光子の保護にガラス板を使用したものが好ましく用いられる。輝点異物はセルロースエステルに含まれる未酢化もしくは低酢化度のセルロースがその原因の１つと考えられ、輝点異物の少ないセルロースエステルを用いる（置換度の分散の小さいセルロースエステルを用いる）ことと、溶融したセルロースエステルを濾過すること、或いはセルロースエステルの合成後期の過程や沈殿物を得る過程の少なくともいずれかにおいて、一度溶液状態として同様に濾過工程を経由して輝点異物を除去することもできる。溶融セルロースエステルは粘度が高いため、後者の方法の方が効率がよい。 In addition, the cellulose ester used in the present invention preferably has few bright spot foreign matters when formed into a film. A bright spot foreign material is an arrangement in which two polarizing plates are arranged orthogonally (crossed Nicols), a cellulose ester film is arranged between them, light from the light source is applied from one side, and the cellulose ester film is applied from the other side. This is the point where the light from the light source appears to leak when observed. At this time, the polarizing plate used for the evaluation is desirably composed of a protective film having no bright spot foreign matter, and a polarizing plate using a glass plate for protecting the polarizer is preferably used. One of the causes of bright spot foreign matter is the unacetylated or low acetylated cellulose contained in the cellulose ester. Use a cellulose ester with less bright spot foreign matter (use a cellulose ester with a small dispersion degree of substitution). And filtering the melted cellulose ester, or removing the bright spot foreign matters through the filtration process in the same way once in the solution state in at least one of the process of synthesizing the cellulose ester and the process of obtaining the precipitate You can also. Since the molten cellulose ester has a high viscosity, the latter method is more efficient.
　フィルム膜厚が薄くなるほど単位面積当たりの輝点異物数は少なくなり、フィルムに含まれるセルロースエステルの含有量が少なくなるほど輝点異物は少なくなる傾向があるが、輝点異物は、輝点の直径０．０１ｍｍ以上が２００個／ｃｍ２以下であることが好ましく、１００個／ｃｍ２以下であることがより好ましく、５０個／ｃｍ２以下であることが更に好ましく、３０個／ｃｍ２以下であることがさらにより好ましく、１０個／ｃｍ２以下であることが更に好ましいが、皆無であることが最も好ましい。また、０．００５～０．０１ｍｍ以下の輝点についても２００個／ｃｍ２以下であることが好ましく、１００個／ｃｍ２以下であることがより好ましく、５０個／ｃｍ２以下であることがさらにより好ましく、３０個／ｃｍ２以下であることが更に好ましく、１０個／ｃｍ２以下であることが更に好ましいが、皆無であることが最も好ましい。 As the film thickness decreases, the number of bright spot foreign matter per unit area decreases, and as the cellulose ester content in the film decreases, the bright spot foreign matter tends to decrease. 0.01 mm or more is preferably 200 pieces / cm 2 or less, more preferably 100 pieces / cm 2 or less, further preferably 50 pieces / cm 2 or less, and 30 pieces / cm 2 or less. More preferably, it is more preferably 10 pieces / cm 2 or less, but most preferably none. The number of bright spots of 0.005 to 0.01 mm or less is also preferably 200 / cm 2 or less, more preferably 100 / cm 2 or less, and 50 / cm 2 or less. Even more preferred is 30 / cm 2 or less, still more preferred is 10 / cm 2 or less, and most preferred is none.
　輝点異物を溶融濾過によって除去する場合、セルロースエステルを単独で溶融させたものを濾過するよりも劣化防止剤、可塑剤等を添加混合したセルロースエステル組成物を濾過することが輝点異物の除去効率が高く好ましい。もちろん、セルロースエステルの合成の際に溶媒に溶解させて濾過により低減させてもよい。紫外線吸収剤、その他の添加物も適宜混合したものを濾過することができる。濾過はセルロースエステルを含む溶融物の粘度が１００００Ｐａ・ｓ以下で濾過されることが好ましく、５０００Ｐａ・ｓ以下がより好ましく、１０００Ｐａ・ｓ以下が更に好ましく、５００Ｐａ・ｓ以下であることがさらにより好ましい。濾材としては、ガラス繊維、セルロース繊維、濾紙、四フッ化エチレン樹脂等の弗素樹脂等の従来公知のものが好ましく用いられるが、特にセラミックス、金属等が好ましく用いられる。絶対濾過精度としては５０μｍ以下のものが好ましく用いられ、３０μｍ以下のものがより好ましく、１０μｍ以下のものがさらにより好ましく、５μｍ以下のものが更に好ましく用いられる。これらは適宜組み合わせて使用することもできる。濾材はサーフェースタイプでもデプスタイプでも用いることができるが、デプスタイプの方が比較的目詰まりしにくく好ましく用いられる。 When removing bright spot foreign matter by melt filtration, filtering the cellulose ester composition to which a deterioration inhibitor, a plasticizer, etc. are added and mixed is more effective than filtering the melted cellulose ester alone. High efficiency is preferable. Of course, the cellulose ester may be dissolved in a solvent during the synthesis and reduced by filtration. What mixed the ultraviolet absorber and other additives suitably can be filtered. Filtration is preferably performed at a viscosity of a melt containing cellulose ester of 10,000 Pa · s or less, more preferably 5000 Pa · s or less, even more preferably 1000 Pa · s or less, and even more preferably 500 Pa · s or less. . As the filter medium, conventionally known materials such as glass fibers, cellulose fibers, filter paper, and fluorine resins such as tetrafluoroethylene resin are preferably used, and ceramics, metals and the like are particularly preferably used. The absolute filtration accuracy is preferably 50 μm or less, more preferably 30 μm or less, still more preferably 10 μm or less, and even more preferably 5 μm or less. These can be used in combination as appropriate. The filter medium can be either a surface type or a depth type, but the depth type is preferably used because it is relatively less clogged.
　別の実施態様では、原料のセルロースエステルは少なくとも一度溶媒に溶解させた後、溶媒を乾燥させたセルロースエステルを用いてもよい。その際には劣化防止剤、可塑剤、紫外線吸収剤、及びマット剤の少なくとも１つ以上と共に溶媒に溶解させた後、乾燥させたセルロースエステルを用いる。溶媒としては、メチレンクロライド、酢酸メチル、ジオキソラン等の溶液流延法で用いられる良溶媒を用いることができ、同時にメタノール、エタノール、ブタノール等の貧溶媒を用いてもよい。溶解の過程で－２０℃以下に冷却したり、８０℃以上に加熱したりしてもよい。このようなセルロースエステルを用いると、溶融状態にした時の各添加物を均一にしやすく、光学特性を均一にできることがある。 In another embodiment, the cellulose ester obtained by dissolving the raw material cellulose ester at least once in a solvent and then drying the solvent may be used. In that case, a cellulose ester which has been dissolved in a solvent together with at least one of a deterioration inhibitor, a plasticizer, an ultraviolet absorber and a matting agent and then dried is used. As the solvent, a good solvent used in a solution casting method such as methylene chloride, methyl acetate or dioxolane can be used, and a poor solvent such as methanol, ethanol or butanol may be used at the same time. In the course of dissolution, it may be cooled to −20 ° C. or lower or heated to 80 ° C. or higher. When such a cellulose ester is used, each additive in a molten state can be easily made uniform, and optical characteristics can be made uniform.
　本発明の光学フィルムはセルロースエステル以外の高分子成分を適宜混合したものでもよい。混合される高分子成分はセルロースエステルと相溶性に優れるものが好ましく、フィルムにした時の透過率が８０％以上、更に好ましくは９０％以上、更に好ましくは９２％以上であることが好ましい。 The optical film of the present invention may be appropriately mixed with polymer components other than cellulose ester. The polymer component to be mixed is preferably one having excellent compatibility with the cellulose ester, and the transmittance when formed into a film is preferably 80% or more, more preferably 90% or more, and further preferably 92% or more.
　《可塑剤》
　本発明において、光学フィルム中に可塑剤の少なくとも１種を添加することが好ましい。 《Plasticizer》
In the present invention, it is preferable to add at least one plasticizer to the optical film.
　可塑剤とは、一般的には高分子中に添加することによって脆弱性を改良したり、柔軟性を付与したりする効果のある添加剤であるが、本発明においては、可塑剤を添加することによって光学フィルムの機械的性質向上、引き裂き強度向上、耐吸水性付与、水分透過率の低減等の効果が見られることもあるため、このような効果を有する材料を可塑剤として用いることがより好ましい。 Generally, a plasticizer is an additive having an effect of improving brittleness or imparting flexibility by adding it to a polymer. In the present invention, a plasticizer is added. As a result, there are cases where effects such as improvement of mechanical properties of optical film, improvement of tearing strength, provision of water absorption resistance, reduction of moisture permeability, etc. can be seen. Therefore, it is more preferable to use a material having such an effect as a plasticizer. preferable.
　本発明に好ましく用いられる可塑剤としては、例えば、リン酸エステル系可塑剤、多価アルコールエステル系可塑剤（エチレングリコールエステル系可塑剤、グリセリンエステル系可塑剤、ジグリセリンエステル系可塑剤など）、多価カルボン酸エステル系可塑剤、炭水化物エステル系可塑剤、ポリマー可塑剤等が挙げられる。 As a plasticizer preferably used in the present invention, for example, phosphate ester plasticizer, polyhydric alcohol ester plasticizer (ethylene glycol ester plasticizer, glycerin ester plasticizer, diglycerin ester plasticizer, etc.), Examples thereof include polyvalent carboxylic acid ester plasticizers, carbohydrate ester plasticizers, and polymer plasticizers.
　この中でも多価アルコールエステル系可塑剤、炭水化物エステル系可塑剤、及びポリマー可塑剤が好ましく、更に多価アルコールエステル系可塑剤及び炭水化物エステル系可塑剤が好ましい。 Of these, polyhydric alcohol ester plasticizers, carbohydrate ester plasticizers, and polymer plasticizers are preferred, and polyhydric alcohol ester plasticizers and carbohydrate ester plasticizers are more preferred.
　また、可塑剤は液体であっても固体であっても良く、組成物の制約上無色であることが好ましい。 The plasticizer may be a liquid or a solid, and is preferably colorless due to the restrictions of the composition.
　添加量は光学物性・機械物性に悪影響がなければ良く、その配合量は、本発明の目的を損なわない範囲で適宜選択され、本発明に係るセルロースエステルの質量に対して、好ましくは１～２５質量％含有することを特徴とする光学フィルムである。１質量％よりも少ないと平面性改善の効果が認められず、２５質量％よりも多いとブリードアウトが発生しやすくなり、フィルムの経時安定性が低下するために好ましくない。 The addition amount may be as long as it does not adversely affect the optical properties and mechanical properties, and the blending amount is appropriately selected within the range not impairing the object of the present invention, and is preferably 1 to 25 with respect to the mass of the cellulose ester according to the present invention. It is an optical film characterized by containing mass%. When the content is less than 1% by mass, the effect of improving the flatness is not recognized, and when the content is more than 25% by mass, bleeding out easily occurs and the temporal stability of the film decreases, which is not preferable.
　より好ましくは可塑剤を３～２０質量％含有する光学フィルムであり、更に好ましくは５～１５質量％含有する光学フィルムである。 More preferred is an optical film containing 3 to 20% by mass of a plasticizer, and further preferred is an optical film containing 5 to 15% by mass.
　以下、本発明に用いられる可塑剤について具体例に説明するが、本発明はこれらに限定されるものではない。 Hereinafter, specific examples of the plasticizer used in the present invention will be described, but the present invention is not limited thereto.
　本発明においては、多価アルコールと１価のカルボン酸からなるエステル系可塑剤、及び多価カルボン酸と１価のアルコールからなるエステル系可塑剤はセルロースエステルと親和性が高いので好ましく、多価アルコールと１価のカルボン酸からなるエステル系可塑剤はセルロースエステルと親和性がさらに高まるので、特に好ましい。 In the present invention, an ester plasticizer comprising a polyhydric alcohol and a monovalent carboxylic acid, and an ester plasticizer comprising a polyvalent carboxylic acid and a monohydric alcohol are preferred because of their high affinity with the cellulose ester. An ester plasticizer composed of an alcohol and a monovalent carboxylic acid is particularly preferable because the affinity with the cellulose ester is further increased.
　なお、多価アルコールエステル系の可塑剤とは、一分子中に複数の水酸基を有する化合物と、１価の有機酸とを縮合した化合物を多価アルコールエステル系可塑剤と称し、多価カルボン酸エステル系の可塑剤とは、一分子中に複数のカルボン酸基を有する化合物と、複数の１価のアルコールまたはフェノールとが縮合した化合物を、多価カルボン酸エステル系可塑剤と称する。 The polyhydric alcohol ester plasticizer is a compound obtained by condensing a compound having a plurality of hydroxyl groups in one molecule and a monovalent organic acid as a polyhydric alcohol ester plasticizer. An ester plasticizer refers to a compound obtained by condensing a compound having a plurality of carboxylic acid groups in one molecule and a plurality of monovalent alcohols or phenols as a polyvalent carboxylic ester plasticizer.
　本発明において好ましく用いられるエステル系可塑剤の原料である多価アルコールの例としては、例えば以下のようなものを挙げることができるが、本発明はこれらに限定されるものではない。 Examples of the polyhydric alcohol that is a raw material of the ester plasticizer that is preferably used in the present invention include the following, but the present invention is not limited thereto.
　アドニトール、アラビトール、エチレングリコール、グリセリン、ジグリセリン、ジエチレングリコール、トリエチレングリコール、テトラエチレングリコール、１，２－プロパンジオール、１，３－プロパンジオール、ジプロピレングリコール、トリプロピレングリコール、１，２－ブタンジオール、１，３－ブタンジオール、１，４－ブタンジオール、ジブチレングリコール、１，２，４－ブタントリオール、１，５－ペンタンジオール、１，６－ヘキサンジオール、ヘキサントリオール、ガラクチトール、マンニトール、３－メチルペンタン－１，３，５－トリオール、ピナコール、ソルビトール、トリメチロールプロパン、ジトリメチロールプロパン、トリメチロールエタン、ペンタエリスリトール、ジペンタエリスリトール、キシリトール等を挙げることができる。特に、エチレングリコール、グリセリン、トリメチロールプロパンが好ましい。 Adonitol, arabitol, ethylene glycol, glycerin, diglycerin, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol 1,3-butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, galactitol, mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, ditrimethylolpropane, trimethylolethane, pentaerythritol, dipentaerythritol, key And the like can be given Lithol. In particular, ethylene glycol, glycerin, and trimethylolpropane are preferable.
　また、好ましい有機酸の例としては、酢酸、プロピオン酸、酪酸、イソ酪酸、ピバリン酸、アクリル酸、メタクリル酸、シクロヘキサンカルボン酸、安息香酸、アニス酸、３，４，５－トリメトキシ安息香酸、トルイル酸、ｔｅｒｔ－ブチル安息香酸、ナフトエ酸、ピコリン酸等が挙げられるが、セルロースエステルの透湿度を低減する効果が高い不飽和カルボン酸、例えば芳香族カルボン酸によって多価アルコールエステルを形成していることが好ましい。 Examples of preferred organic acids include acetic acid, propionic acid, butyric acid, isobutyric acid, pivalic acid, acrylic acid, methacrylic acid, cyclohexanecarboxylic acid, benzoic acid, anisic acid, 3,4,5-trimethoxybenzoic acid, toluyl Acid, tert-butylbenzoic acid, naphthoic acid, picolinic acid, and the like. Polyhydric alcohol ester is formed by unsaturated carboxylic acid, for example, aromatic carboxylic acid, which is highly effective in reducing the moisture permeability of cellulose ester. It is preferable.
　多価アルコールエステルに用いられる有機酸は１種類でもよいし、２種以上の混合であってもよい。また、多価アルコール中のＯＨ基は、全てエステル化してもよいし、一部をＯＨ基のままで残してもよい。 The organic acid used for the polyhydric alcohol ester may be one kind or a mixture of two or more kinds. Moreover, all the OH groups in the polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are.
　多価アルコールエステル系の一つであるエチレングリコールエステル系の可塑剤としては、具体的には、エチレングリコールジアセテート、エチレングリコールジブチレート等のエチレングリコールアルキルエステル系の可塑剤、エチレングリコールジシクロプロピルカルボキシレート、エチレングリコールジシクロヘキルカルボキシレート等のエチレングリコールシクロアルキルエステル系の可塑剤、エチレングリコールジベンゾエート、エチレングリコールジ４－メチルベンゾエート等のエチレングリコールアリールエステル系の可塑剤が挙げられる。 Specific examples of ethylene glycol ester plasticizers that are one of the polyhydric alcohol esters include ethylene glycol alkyl ester plasticizers such as ethylene glycol diacetate and ethylene glycol dibutyrate, and ethylene glycol dicyclopropyl. Examples thereof include ethylene glycol cycloalkyl ester plasticizers such as carboxylate and ethylene glycol dicyclohexylcarboxylate, and ethylene glycol aryl ester plasticizers such as ethylene glycol dibenzoate and ethylene glycol di4-methylbenzoate.
　これらアルキレート基、シクロアルキレート基、アリレート基は、同一でもあっても異なっていてもよく、更に置換されていてもよい。 These alkylate groups, cycloalkylate groups, and arylate groups may be the same or different, and may be further substituted.
　またアルキレート基、シクロアルキレート基、アリレート基のミックスでもよく、またこれら置換基同士が共有結合で結合していてもよい。 Also, a mixture of alkylate group, cycloalkylate group and arylate group may be used, and these substituents may be bonded by a covalent bond.
　更にエチレングリコール部も置換されていてもよく、エチレングリコールエステルの部分構造が、ポリマーの一部、或いは規則的にペンダントされていてもよく、また酸化防止剤、酸掃去剤、紫外線吸収剤等の添加剤の分子構造の一部に導入されていてもよい。 Further, the ethylene glycol part may be substituted, and the ethylene glycol ester partial structure may be part of the polymer or regularly pendant, and may be an antioxidant, an acid scavenger, an ultraviolet absorber, etc. It may be introduced into a part of the molecular structure of the additive.
　多価アルコールエステル系の一つであるグリセリンエステル系の可塑剤としては、具体的にはトリアセチン、トリブチリン、グリセリンジアセテートカプリレート、グリセリンオレートプロピオネート等のグリセリンアルキルエステル、グリセリントリシクロプロピルカルボキシレート、グリセリントリシクロヘキシルカルボキシレート等のグリセリンシクロアルキルエステル、グリセリントリベンゾエート、グリセリン４－メチルベンゾエート等のグリセリンアリールエステル、ジグリセリンテトラアセチレート、ジグリセリンテトラプロピオネート、ジグリセリンアセテートトリカプリレート、ジグリセリンテトララウレート、等のジグリセリンアルキルエステル、ジグリセリンテトラシクロブチルカルボキシレート、ジグリセリンテトラシクロペンチルカルボキシレート等のジグリセリンシクロアルキルエステル、ジグリセリンテトラベンゾエート、ジグリセリン３－メチルベンゾエート等のジグリセリンアリールエステル等が挙げられる。これらアルキレート基、シクロアルキルカルボキシレート基、アリレート基は同一でもあっても異なっていてもよく、更に置換されていてもよい。 Specific examples of glycerin ester plasticizers that are one of the polyhydric alcohol esters include glycerol alkyl esters such as triacetin, tributyrin, glycerol diacetate caprylate, glycerol oleate propionate, and glycerol tricyclopropylcarboxylate. Glycerol glycerol esters such as glycerol tricyclohexyl carboxylate, glycerol aryl esters such as glycerol tribenzoate and glycerol 4-methylbenzoate, diglycerol tetraacetylate, diglycerol tetrapropionate, diglycerol acetate tricaprylate, diglycerol Diglycerol alkyl esters such as tetralaurate, diglycerol tetracyclobutylcarboxylate, diglycerol Diglycerol cycloalkyl esters such as La cyclopentyl carboxylate, diglycerin tetrabenzoate, diglycerin aryl ester such as diglycerin 3-methylbenzoate or the like. These alkylate groups, cycloalkylcarboxylate groups, and arylate groups may be the same or different, and may be further substituted.
　またアルキレート基、シクロアルキルカルボキシレート基、アリレート基のミックスでもよく、またこれら置換基同士が共有結合で結合していてもよい。更にグリセリン、ジグリセリン部も置換されていてもよく、グリセリンエステル、ジグリセリンエステルの部分構造がポリマーの一部、或いは規則的にペンダントされていてもよく、また酸化防止剤、酸掃去剤、紫外線吸収剤等の添加剤の分子構造の一部に導入されていてもよい。 Further, it may be a mix of alkylate group, cycloalkylcarboxylate group, and arylate group, and these substituents may be bonded by a covalent bond. Furthermore, the glycerin and diglycerin part may be substituted, the partial structure of the glycerin ester and the diglycerin ester may be part of the polymer or regularly pendant, and the antioxidant, acid scavenger, You may introduce | transduce into a part of molecular structure of additives, such as a ultraviolet absorber.
　その他の多価アルコールエステル系の可塑剤としては、具体的には特開２００３－１２８２３号公報の段落３０～３３記載の多価アルコールエステル系可塑剤、ペンタエリスリトールテトラベンゾエート等が挙げられる。 Specific examples of other polyhydric alcohol ester plasticizers include polyhydric alcohol ester plasticizers described in paragraphs 30 to 33 of JP-A No. 2003-12823, pentaerythritol tetrabenzoate, and the like.
　これらアルキレート基、シクロアルキルカルボキシレート基、アリレート基は、同一でもあっても異なっていてもよく、更に置換されていてもよい。またアルキレート基、シクロアルキルカルボキシレート基、アリレート基のミックスでもよく、またこれら置換基同士が共有結合で結合していてもよい。 These alkylate groups, cycloalkylcarboxylate groups, and arylate groups may be the same or different, and may be further substituted. Moreover, the mix of alkylate group, a cycloalkyl carboxylate group, and an arylate group may be sufficient, and these substituents may couple | bond together by the covalent bond.
　更に多価アルコール部も置換されていてもよく、多価アルコールの部分構造が、ポリマーの一部、或いは規則的にペンダントされていてもよく、また酸化防止剤、酸掃去剤、紫外線吸収剤等の添加剤の分子構造の一部に導入されていてもよい。 Furthermore, the polyhydric alcohol part may be substituted, and the partial structure of the polyhydric alcohol may be part of the polymer or regularly pendant, and may be an antioxidant, an acid scavenger, an ultraviolet absorber. May be introduced into a part of the molecular structure of the additive.
　上記多価アルコールと１価のカルボン酸からなるエステル系可塑剤の中では、アルキル多価アルコールアリールエステルが好ましく、具体的には上記のエチレングリコールジベンゾエート、グリセリントリベンゾエート、ジグリセリンテトラベンゾエート、特開２００３－１２８２３号公報の段落３１記載例示化合物１６が挙げられる。 Among the ester plasticizers composed of the polyhydric alcohol and the monovalent carboxylic acid, alkyl polyhydric alcohol aryl esters are preferred. Specifically, the above-mentioned ethylene glycol dibenzoate, glycerin tribenzoate, diglycerin tetrabenzoate, Examples thereof include the exemplified compound 16 described in paragraph 31 of JP-A-2003-12823.
　多価カルボン酸エステル系の一つであるジカルボン酸エステル系の可塑剤としては、具体的には、ジドデシルマロネート、ジオクチルアジペート、ジブチルセバケート等のアルキルジカルボン酸アルキルエステル系の可塑剤、ジシクロペンチルサクシネート、ジシクロヘキシルアジーペート等のアルキルジカルボン酸シクロアルキルエステル系の可塑剤、ジフェニルサクシネート、ジ４－メチルフェニルグルタレート等のアルキルジカルボン酸アリールエステル系の可塑剤、ジヘキシル－１，４－シクロヘキサンジカルボキシレート、ジデシルビシクロ［２．２．１］ヘプタン－２，３－ジカルボキシレート等のシクロアルキルジカルボン酸アルキルエステル系の可塑剤、ジシクロヘキシル－１，２－シクロブタンジカルボキシレート、ジシクロプロピル－１，２－シクロヘキシルジカルボキシレート等のシクロアルキルジカルボン酸シクロアルキルエステル系の可塑剤、ジフェニル－１，１－シクロプロピルジカルボキシレート、ジ２－ナフチル－１，４－シクロヘキサンジカルボキシレート等のシクロアルキルジカルボン酸アリールエステル系の可塑剤、ジエチルフタレート、ジメチルフタレート、ジオクチルフタレート、ジブチルフタレート、ジ－２－エチルヘキシルフタレート等のアリールジカルボン酸アルキルエステル系の可塑剤、ジシクロプロピルフタレート、ジシクロヘキシルフタレート等のアリールジカルボン酸シクロアルキルエステル系の可塑剤、ジフェニルフタレート、ジ４－メチルフェニルフタレート等のアリールジカルボン酸アリールエステル系の可塑剤、ブチルフタリルブチルグリコレート、エチルフタリルエチルグリコレート等のグリコール酸エステル系の可塑剤、クエン酸アセチルトリメチル、クエン酸アセチルトリエチル、クエン酸アセチルトリブチル等のクエン酸系の可塑剤等が挙げられる。 Specific examples of the dicarboxylic acid ester plasticizer that is one of the polyvalent carboxylic acid esters include alkyl dicarboxylic acid alkyl ester plasticizers such as didodecyl malonate, dioctyl adipate, and dibutyl sebacate. Alkyl dicarboxylic acid cycloalkyl ester plasticizers such as cyclopentyl succinate and dicyclohexyl adipate, alkyl dicarboxylic acid aryl ester plasticizers such as diphenyl succinate and di4-methylphenyl glutarate, dihexyl-1,4-cyclohexane Cycloalkyl dicarboxylic acid alkyl ester plasticizers such as dicarboxylate and didecylbicyclo [2.2.1] heptane-2,3-dicarboxylate, dicyclohexyl-1,2-cyclobutanedicarboxylate, Cyclopropyl-1,2-cyclohexyl dicarboxylate and other cycloalkyl dicarboxylic acid cycloalkyl ester plasticizers, diphenyl-1,1-cyclopropyl dicarboxylate, di-2-naphthyl-1,4-cyclohexane dicarboxylate Cycloalkyldicarboxylic acid aryl ester plasticizers such as diethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, and other aryl dicarboxylic acid alkyl ester plasticizers, dicyclopropyl phthalate, dicyclohexyl phthalate Aryl dicarboxylic acid cycloalkyl ester plasticizers such as diphenyl phthalate, di4-methylphenyl phthalate and other aryl dicarboxylic acid aryl ester plastics And glycolic acid ester plasticizers such as butylphthalylbutyl glycolate and ethylphthalylethyl glycolate, and citric acid plasticizers such as acetyltrimethyl citrate, acetyltriethyl citrate, and acetyltributyl citrate. .
　これらアルコキシ基、シクロアルコキシ基は、同一でもあっても異なっていてもよく、また一置換でもよく、これらの置換基は更に置換されていてもよい。アルキル基、シクロアルキル基はミックスでもよく、またこれら置換基同士が共有結合で結合していてもよい。 These alkoxy groups and cycloalkoxy groups may be the same or different, may be mono-substituted, and these substituents may be further substituted. The alkyl group and cycloalkyl group may be mixed, or these substituents may be bonded together by a covalent bond.
　更にフタル酸の芳香環も置換されていてよく、ダイマー、トリマー、テトラマー等の多量体でもよい。またフタル酸エステルの部分構造が、ポリマーの一部、或いは規則的にポリマーへペンダントされていてもよく、酸化防止剤、酸掃去剤、紫外線吸収剤等の添加剤の分子構造の一部に導入されていてもよい。 Furthermore, the aromatic ring of phthalic acid may be substituted, and a multimer such as a dimer, trimer or tetramer may be used. Also, the partial structure of phthalate ester may be part of the polymer or regularly pendant to the polymer, and it may be part of the molecular structure of additives such as antioxidants, acid scavengers, and UV absorbers. It may be introduced.
　その他の多価カルボン酸エステル系の可塑剤としては、具体的にはトリドデシルトリカルバレート、トリブチル－ｍｅｓｏ－ブタン－１，２，３，４－テトラカルボキシレート等のアルキル多価カルボン酸アルキルエステル系の可塑剤、トリシクロヘキシルトリカルバレート、トリシクロプロピル－２－ヒドロキシ－１，２，３－プロパントリカルボキシレート等のアルキル多価カルボン酸シクロアルキルエステル系の可塑剤、トリフェニル２－ヒドロキシ－１，２，３－プロパントリカルボキシレート、テトラ３－メチルフェニルテトラヒドロフラン－２，３，４，５－テトラカルボキシレート等のアルキル多価カルボン酸アリールエステル系の可塑剤、テトラヘキシル－１，２，３，４－シクロブタンテトラカルボキシレート、テトラブチル－１，２，３，４－シクロペンタンテトラカルボキシレート等のシクロアルキル多価カルボン酸アルキルエステル系の可塑剤、テトラシクロプロピル－１，２，３，４－シクロブタンテトラカルボキシレート、トリシクロヘキシル－１，３，５－シクロヘキシルトリカルボキシレート等のシクロアルキル多価カルボン酸シクロアルキルエステル系の可塑剤、トリフェニル－１，３，５－シクロヘキシルトリカルボキシレート、ヘキサ４－メチルフェニル－１，２，３，４，５，６－シクロヘキシルヘキサカルボキシレート等のシクロアルキル多価カルボン酸アリールエステル系の可塑剤、トリドデシルベンゼン－１，２，４－トリカルボキシレート、テトラオクチルベンゼン－１，２，４，５－テトラカルボキシレート等のアリール多価カルボン酸アルキルエステル系の可塑剤、トリシクロペンチルベンゼン－１，３，５－トリカルボキシレート、テトラシクロヘキシルベンゼン－１，２，３，５－テトラカルボキシレート等のアリール多価カルボン酸シクロアルキルエステル系の可塑剤トリフェニルベンゼン－１，３，５－テトラカルボキシレート、ヘキサ４－メチルフェニルベンゼン－１，２，３，４，５，６－ヘキサカルボキシレート等のアリール多価カルボン酸アリールエステル系の可塑剤が挙げられる。 Other polycarboxylic acid ester plasticizers include alkyl polycarboxylic acid alkyl esters such as tridodecyl tricarbarate and tributyl-meso-butane-1,2,3,4-tetracarboxylate. Plasticizers, alkylpolycarboxylic acid cycloalkylester plasticizers such as tricyclohexyl tricarbarate, tricyclopropyl-2-hydroxy-1,2,3-propanetricarboxylate, triphenyl 2-hydroxy- Alkyl polyvalent carboxylic acid aryl ester plasticizers such as 1,2,3-propanetricarboxylate, tetra-3-methylphenyltetrahydrofuran-2,3,4,5-tetracarboxylate, tetrahexyl-1,2, 3,4-cyclobutanetetracarboxylate, tetra Cycloalkyl polycarboxylic acid alkyl ester plasticizers such as til-1,2,3,4-cyclopentanetetracarboxylate, tetracyclopropyl-1,2,3,4-cyclobutanetetracarboxylate, tricyclohexyl- Cycloalkyl polycarboxylic acid cycloalkyl ester plasticizers such as 1,3,5-cyclohexyl tricarboxylate, triphenyl-1,3,5-cyclohexyl tricarboxylate, hexa-4-methylphenyl-1,2, Cycloalkyl polycarboxylic acid aryl ester plasticizers such as 3,4,5,6-cyclohexylhexacarboxylate, tridodecylbenzene-1,2,4-tricarboxylate, tetraoctylbenzene-1,2,4 Aryl, such as 5-tetracarboxylate Carboxylic acid alkyl ester plasticizers, such as tricyclopentylbenzene-1,3,5-tricarboxylate, tetracyclohexylbenzene-1,2,3,5-tetracarboxylate, etc. Plasticizers of aryl polyvalent carboxylic acid aryl esters such as plasticizers triphenylbenzene-1,3,5-tetracarboxylate, hexa-4-methylphenylbenzene-1,2,3,4,5,6-hexacarboxylate Agents.
　これらアルコキシ基、シクロアルコキシ基は、同一でもあっても異なっていてもよく、また１置換でもよく、これらの置換基は更に置換されていてもよい。アルキル基、シクロアルキル基はミックスでもよく、またこれら置換基同士が共有結合で結合していてもよい。 These alkoxy groups and cycloalkoxy groups may be the same or different, and may be monosubstituted, and these substituents may be further substituted. The alkyl group and cycloalkyl group may be mixed, or these substituents may be bonded together by a covalent bond.
　更にフタル酸の芳香環も置換されていてよく、ダイマー、トリマー、テトラマー等の多量体でもよい。またフタル酸エステルの部分構造がポリマーの一部、或いは規則的にポリマーへペンダントされていてもよく、酸化防止剤、酸掃去剤、紫外線吸収剤等の添加剤の分子構造の一部に導入されていてもよい。 Furthermore, the aromatic ring of phthalic acid may be substituted, and a multimer such as a dimer, trimer or tetramer may be used. Also, the partial structure of phthalate ester may be part of the polymer or regularly pendant into the polymer, and introduced into part of the molecular structure of additives such as antioxidants, acid scavengers, UV absorbers, etc. May be.
　上記多価カルボン酸と１価のアルコールからなるエステル系可塑剤の中では、アルキルジカルボン酸アルキルエステルが好ましく、具体的には上記のジオクチルアジペートが挙げられる。 Among the ester plasticizers composed of the polyvalent carboxylic acid and the monohydric alcohol, alkyl dicarboxylic acid alkyl esters are preferable, and specific examples include the dioctyl adipate.
　本発明に用いられるその他の可塑剤としては、リン酸エステル系可塑剤、炭水化物エステル系可塑剤、ポリマー可塑剤等が挙げられる。 Other plasticizers used in the present invention include phosphate ester plasticizers, carbohydrate ester plasticizers, polymer plasticizers, and the like.
　リン酸エステル系の可塑剤としては、具体的には、トリアセチルホスフェート、トリブチルホスフェート等のリン酸アルキルエステル、トリシクロベンチルホスフェート、シクロヘキシルホスフェート等のリン酸シクロアルキルエステル、トリフェニルホスフェート、トリクレジルホスフェート、クレジルフェニルホスフェート、オクチルジフェニルホスフェート、ジフェニルビフェニルホスフェート、トリオクチルホスフェート、トリブチルホスフェート、トリナフチルホスフェート、トリキシリルオスフェート、トリスオルト－ビフェニルホスフェート等のリン酸アリールエステルが挙げられる。これらの置換基は同一でもあっても異なっていてもよく、更に置換されていてもよい。またアルキル基、シクロアルキル基、アリール基のミックスでもよく、また置換基同士が共有結合で結合していてもよい。 Specific examples of the phosphoric acid ester plasticizer include phosphoric acid alkyl esters such as triacetyl phosphate and tributyl phosphate, phosphoric acid cycloalkyl esters such as tricyclopentyl phosphate and cyclohexyl phosphate, triphenyl phosphate, and trichlorate. Examples thereof include phosphoric acid aryl esters such as zil phosphate, cresyl phenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, trinaphthyl phosphate, trixylyl phosphate, tris ortho-biphenyl phosphate. These substituents may be the same or different, and may be further substituted. Moreover, the mix of an alkyl group, a cycloalkyl group, and an aryl group may be sufficient, and substituents may couple | bond together by the covalent bond.
　また、エチレンビス（ジメチルホスフェート）、ブチレンビス（ジエチルホスフェート）等のアルキレンビス（ジアルキルホスフェート）、エチレンビス（ジフェニルホスフェート）、プロピレンビス（ジナフチルホスフェート）等のアルキレンビス（ジアリールホスフェート）、フェニレンビス（ジブチルホスフェート）、ビフェニレンビス（ジオクチルホスフェート）等のアリーレンビス（ジアルキルホスフェート）、フェニレンビス（ジフェニルホスフェート）、ナフチレンビス（ジトルイルホスフェート）等のアリーレンビス（ジアリールホスフェート）等のリン酸エステルが挙げられる。これらの置換基は同一でもあっても異なっていてもよく、更に置換されていてもよい。 Also, alkylene bis (dialkyl phosphate) such as ethylene bis (dimethyl phosphate), butylene bis (diethyl phosphate), alkylene bis (diaryl phosphate) such as ethylene bis (diphenyl phosphate), propylene bis (dinaphthyl phosphate), phenylene bis (dibutyl) Phosphate), arylene bis (dialkyl phosphate) such as biphenylene bis (dioctyl phosphate), phosphate esters such as arylene bis (diaryl phosphate) such as phenylene bis (diphenyl phosphate) and naphthylene bis (ditoluyl phosphate). These substituents may be the same or different, and may be further substituted.
　またアルキル基、シクロアルキル基、アリール基のミックスでもよく、また置換基同士が共有結合で結合していてもよい。 Further, it may be a mix of an alkyl group, a cycloalkyl group, and an aryl group, and the substituents may be covalently bonded to each other.
　更にリン酸エステルの部分構造が、ポリマーの一部、或いは規則的にペンダントされていてもよく、また酸化防止剤、酸掃去剤、紫外線吸収剤等の添加剤の分子構造の一部に導入されていてもよい。上記化合物の中では、リン酸アリールエステル、アリーレンビス（ジアリールホスフェート）が好ましく、具体的にはトリフェニルホスフェート、フェニレンビス（ジフェニルホスフェート）が好ましい。 Furthermore, the partial structure of phosphate ester may be part of the polymer, or may be regularly pendant, and also introduced into part of the molecular structure of additives such as antioxidants, acid scavengers, UV absorbers, etc. May be. Among the above-mentioned compounds, phosphoric acid aryl ester and arylene bis (diaryl phosphate) are preferable, and specifically, triphenyl phosphate and phenylene bis (diphenyl phosphate) are preferable.
　次に、炭水化物エステル系可塑剤について説明する。炭水化物とは、糖類がピラノースまたはフラノース（６員環または５員環）の形態で存在する単糖類、二糖類または三糖類を意味する。炭水化物の非限定的例としては、グルコース、サッカロース、ラクトース、セロビオース、マンノース、キシロース、リボース、ガラクトース、アラビノース、フルクトース、ソルボース、セロトリオース及びラフィノース等が挙げられる。 Next, the carbohydrate ester plasticizer will be described. The carbohydrate means a monosaccharide, disaccharide or trisaccharide in which the saccharide is present in the form of pyranose or furanose (6-membered ring or 5-membered ring). Non-limiting examples of carbohydrates include glucose, saccharose, lactose, cellobiose, mannose, xylose, ribose, galactose, arabinose, fructose, sorbose, cellotriose and raffinose.
　炭水化物エステルとは、炭水化物の水酸基とカルボン酸が脱水縮合してエステル化合物を形成したものを指し、詳しくは、炭水化物の脂肪族カルボン酸エステル、或いは芳香族カルボン酸エステルを意味する。脂肪族カルボン酸として、例えば酢酸、プロピオン酸等を挙げることができ、芳香族カルボン酸として、例えば安息香酸、トルイル酸、アニス酸等を挙げることができる。 Carbohydrate ester refers to an ester compound formed by dehydration condensation of a hydroxyl group of a carbohydrate and a carboxylic acid, and specifically means an aliphatic carboxylic acid ester or an aromatic carboxylic acid ester of a carbohydrate. Examples of the aliphatic carboxylic acid include acetic acid and propionic acid, and examples of the aromatic carboxylic acid include benzoic acid, toluic acid, and anisic acid.
　炭水化物は、その種類に応じた水酸基の数を有するが、水酸基の一部とカルボン酸が反応してエステル化合物を形成しても、水酸基の全部とカルボン酸が反応してエステル化合物を形成してもよい。 Carbohydrates have a number of hydroxyl groups depending on the type, but even if a part of the hydroxyl group reacts with the carboxylic acid to form an ester compound, the whole hydroxyl group reacts with the carboxylic acid to form an ester compound. Also good.
　本発明においては、水酸基の全部とカルボン酸が反応してエステル化合物を形成するのが好ましい。 In the present invention, it is preferred that all of the hydroxyl groups react with the carboxylic acid to form an ester compound.
　炭水化物エステル系可塑剤として、具体的には、グルコースペンタアセテート、グルコースペンタプロピオネート、グルコースペンタブチレート、サッカロースオクタアセテート、サッカロースオクタベンゾエート等を好ましく挙げることができ、この内、サッカロースオクタアセテート、サッカロースオクタベンゾエートがより好ましく、サッカロースオクタベンゾエートが特に好ましい。上記タイプの炭水化物エステル系可塑剤は、例えば、第一工業製薬社から、“モノペットＳＢ”及び“モノペットＳＯＡ”という商品名で市販されている。 Specific examples of the carbohydrate ester plasticizer include glucose pentaacetate, glucose pentapropionate, glucose pentabtylate, saccharose octaacetate, saccharose octabenzoate and the like. Among these, saccharose octaacetate, saccharose Octabenzoate is more preferred, and sucrose octabenzoate is particularly preferred. The above-mentioned type of carbohydrate ester plasticizer is commercially available from Daiichi Kogyo Seiyaku Co., Ltd. under the trade names “Monopet SB” and “Monopet SOA”.
　ポリマー可塑剤としては、具体的には、脂肪族炭化水素系ポリマー、脂環式炭化水素系ポリマー、ポリアクリル酸エチル、ポリメタクリル酸メチル、メタクリル酸メチルとメタクリル酸－２－ヒドロキシエチルとの共重合体、メタクリル酸メチルとアクリル酸メチルとメタクリル酸－２－ヒドロキシエチルとの共重合体等のアクリル系ポリマー、ポリビニルイソブチルエーテル、ポリＮ－ビニルピロリドン等のビニル系ポリマー、ポリスチレン、ポリ４－ヒドロキシスチレン等のスチレン系ポリマー、ポリブチレンサクシネート、ポリエチレンテレフタレート、ポリエチレンナフタレート等のポリエステル、ポリエチレンオキシド、ポリプロピレンオキシド等のポリエーテル、ポリアミド、ポリウレタン、ポリウレア等が挙げられる。数平均分子量は１０００～５０００００程度が好ましく、特に好ましくは、５０００～２０００００である。１０００以下では揮発性に問題が生じ、５０００００を超えると可塑化能力が低下し、光学フィルムの機械的性質に悪影響を及ぼす。 Specific examples of the polymer plasticizer include aliphatic hydrocarbon polymers, alicyclic hydrocarbon polymers, polyethyl acrylate, polymethyl methacrylate, methyl methacrylate and 2-hydroxyethyl methacrylate. Polymers, acrylic polymers such as copolymers of methyl methacrylate, methyl acrylate and 2-hydroxyethyl methacrylate, vinyl polymers such as polyvinyl isobutyl ether and poly N-vinyl pyrrolidone, polystyrene, poly 4-hydroxy Examples thereof include styrene polymers such as styrene, polyesters such as polybutylene succinate, polyethylene terephthalate and polyethylene naphthalate, polyethers such as polyethylene oxide and polypropylene oxide, polyamides, polyurethanes and polyureas. The number average molecular weight is preferably about 1,000 to 500,000, particularly preferably 5,000 to 200,000. If it is 1000 or less, a problem arises in volatility, and if it exceeds 500000, the plasticizing ability is lowered, and the mechanical properties of the optical film are adversely affected.
　これらポリマー可塑剤は１種の繰り返し単位からなる単独重合体でも、複数の繰り返し構造体を有する共重合体でもよい。また、上記ポリマーを２種以上併用して用いてもよい。 These polymer plasticizers may be a homopolymer composed of one type of repeating unit or a copolymer having a plurality of repeating structures. Two or more of the above polymers may be used in combination.
　本発明の光学フィルムにおいて、多価アルコールと１価のカルボン酸からなるエステル系可塑剤、炭水化物エステル系可塑剤を１～２５質量％含有することが好ましいが、それ以外の可塑剤と併用してもよい。 The optical film of the present invention preferably contains 1 to 25% by mass of an ester plasticizer comprising a polyhydric alcohol and a monovalent carboxylic acid, or a carbohydrate ester plasticizer, but in combination with other plasticizers. Also good.
　本発明の光学フィルムにおいて好ましい可塑剤である多価アルコールと１価のカルボン酸からなるエステル系可塑剤は、３価以上のアルコールと１価のカルボン酸からなるエステル系可塑剤がセルロースエステルに対する相溶性が高く、高添加率で添加することができる特徴があるため、他の可塑剤や添加剤を併用してもブリードアウトを発生することがなく、必要に応じて他種の可塑剤や添加剤を容易に併用することができるので最も好ましい。 The ester plasticizer comprising a polyhydric alcohol and a monovalent carboxylic acid, which is a preferred plasticizer in the optical film of the present invention, is an ester plasticizer comprising a trivalent or higher alcohol and a monovalent carboxylic acid in phase with the cellulose ester. Because it has high solubility and can be added at a high addition rate, it does not cause bleed-out even when other plasticizers and additives are used in combination. The agent is most preferable because it can be easily used in combination.
　《劣化防止剤》
　劣化防止剤とは、高分子が熱や酸素、水分、酸などによって分解されることを化学的な作用によって抑制する材料のことである。本発明の光学フィルムは、特に２００℃以上の高温下で成形されるため、高分子の分解・劣化が起きやすい系であり、劣化防止剤を光学フィルム中に含有させることが好ましい。 <Deterioration preventive agent>
The deterioration preventing agent is a material that suppresses decomposition of a polymer by heat, oxygen, moisture, acid, or the like by a chemical action. Since the optical film of the present invention is molded particularly at a high temperature of 200 ° C. or higher, it is a system in which the polymer is easily decomposed and deteriorated, and it is preferable to contain a deterioration inhibitor in the optical film.
　光学フィルムの酸化防止、分解して発生した酸の捕捉、光または熱によるラジカル種基因の分解反応を抑制または禁止する等、解明できていない分解反応を含めて、着色や分子量低下に代表される変質や材料の分解による揮発成分の生成を抑制するために劣化防止剤を用いる。 It is represented by coloring and molecular weight reduction, including decomposition reactions that have not been elucidated, such as oxidation prevention of optical films, capture of acid generated by decomposition, and suppression or prohibition of decomposition reaction due to radical species due to light or heat. Deterioration inhibitors are used to suppress the generation of volatile components due to alteration or material decomposition.
　劣化防止剤としては、例えば、酸化防止剤、ヒンダードアミン光安定剤、酸捕捉剤、金属不活性化剤などが挙げられるが、これらに限定されない。これらは、特開平３－１９９２０１号公報、特開平５－１９０７０７３号公報、特開平５－１９４７８９号公報、特開平５－２７１４７１号公報、特開平６－１０７８５４号公報などに記載がある。これらの中でも、本発明の目的のためには、光学フィルム中に劣化防止剤として酸化防止剤を含むことが好ましい。 Examples of the deterioration preventing agent include, but are not limited to, an antioxidant, a hindered amine light stabilizer, an acid scavenger, and a metal deactivator. These are described in JP-A-3-199201, JP-A-5-1907073, JP-A-5-194789, JP-A-5-271471, JP-A-6-107854, and the like. Among these, for the purpose of the present invention, the optical film preferably contains an antioxidant as a deterioration preventing agent.
　本発明の光学フィルム形成材料中の劣化防止剤は、少なくとも１種以上選択でき、添加する量は、本発明のセルロースエステルの質量に対して、劣化防止剤の添加量は０．０１質量％以上１０質量％以下が好ましく、より好ましくは０．１質量％以上５．０質量％以下であり、更に好ましくは０．２質量％以上２．０質量％以下である。 The deterioration preventing agent in the optical film-forming material of the present invention can be selected from at least one or more. The amount to be added is 0.01% by mass or more with respect to the mass of the cellulose ester of the present invention. 10 mass% or less is preferable, More preferably, it is 0.1 to 5.0 mass%, More preferably, it is 0.2 to 2.0 mass%.
　なお、劣化防止剤の添加量が上記添加量の範囲であると、セルロースエステルへの相溶性の観点から光学フィルムとしての透明性が向上し、また光学フィルムが脆くなることもないので好ましい。 In addition, it is preferable that the addition amount of the deterioration preventing agent is within the above range because the transparency as the optical film is improved from the viewpoint of compatibility with the cellulose ester and the optical film is not brittle.
　光学フィルムは、材料の変質や吸湿性を回避する目的で、構成する材料が１種または複数種のペレットに分割して保存することができる。ペレット化は、加熱時の溶融物の混合性または相溶性が向上でき、または得られたフィルムの光学的な均一性が確保できることもある。 The optical film can be stored by dividing the constituent material into one or more kinds of pellets for the purpose of avoiding material alteration and hygroscopicity. Pelletization may improve the mixing or compatibility of the melt during heating, or may ensure the optical uniformity of the resulting film.
　光学フィルムを加熱溶融するとき、及び加熱溶融したものを後工程で使用するとき、更には製品として消費者のもとで使用されるとき、上述の劣化防止剤が存在することは、材料の劣化や分解に基づく強度や光学的透明性の劣化を低減すること、または材料固有の強度を維持できる観点で優れている。 When the optical film is heated and melted, and when the heated and melted product is used in a post-process, or when used as a product under the consumer, the presence of the above-mentioned deterioration preventing agent is caused by deterioration of the material It is excellent in terms of reducing the strength based on the decomposition and deterioration of optical transparency, or maintaining the strength inherent to the material.
　光学フィルムが加熱により著しく劣化すると、着色が発生して光学フィルムとしては用いることができなくなることがある。 If the optical film is significantly deteriorated by heating, coloring may occur and the optical film may not be used.
　また、液晶表示装置用の位相差フィルムとして用いる際には、リターデーション付与工程（延伸工程）が流延工程の次に実施されるが、光学フィルムが加熱により著しく劣化すると、形成されたフィルムが脆くなり、該延伸工程において破断が生じやすくなったり、目的の位相差フィルムのリターデーション値が発現できなくなったりすることがある。 In addition, when used as a retardation film for a liquid crystal display device, a retardation imparting step (stretching step) is carried out next to the casting step, but when the optical film is significantly deteriorated by heating, the formed film becomes The film may become brittle and may be easily broken during the stretching process, or the retardation value of the target retardation film may not be expressed.
　更には、液晶表示装置用の偏光板保護フィルムとして使用する場合、光学フィルムの劣化は、偏光子との貼合に支障をきたしたりするので好ましくない。 Furthermore, when used as a polarizing plate protective film for a liquid crystal display device, the deterioration of the optical film is unfavorable because it interferes with the bonding with the polarizer.
　そこで、上述の劣化防止剤の存在は、加熱溶融時において可視光領域の着色物の生成を抑制すること、または加熱溶融時及び加熱溶融後のフィルムを構成する材料が分解して生じた揮発成分等によって生じる透過率やヘイズ値の低下といった光学フィルムとして好ましくない劣化を抑制または消滅できる点でも優れている。 Therefore, the presence of the above-mentioned deterioration preventing agent suppresses the generation of a colored material in the visible light region at the time of heating and melting, or a volatile component generated by decomposition of the material constituting the film at the time of heating and melting. It is also excellent in that deterioration unfavorable as an optical film such as a decrease in transmittance and haze value caused by the above can be suppressed or eliminated.
　本発明において液晶表示装置の表示画像は、本発明の光学フィルムを用いるときヘイズ値が１％を超えると影響を与えるため、好ましくはヘイズ値は１％未満、より好ましくは０．５％未満である。また着色性の指標としては黄色度（イエローインデックス、ＹＩ）を用いることができ、好ましくは３．０以下、より好ましくは１．０以下である。黄色度はＪＩＳ－Ｋ－７１０３に基づいて測定することができる。 In the present invention, the display image of the liquid crystal display device is affected when the haze value exceeds 1% when the optical film of the present invention is used. Therefore, the haze value is preferably less than 1%, more preferably less than 0.5%. is there. As an index of colorability, yellowness (yellow index, YI) can be used, preferably 3.0 or less, more preferably 1.0 or less. Yellowness can be measured based on JIS-K-7103.
　上述の光学フィルムの保存或いは製膜工程において、空気中の酸素あるいは水分による劣化反応が併発することがある。 In the optical film storage or film formation process described above, deterioration reactions due to oxygen or moisture in the air may occur at the same time.
　この場合、上記劣化防止剤の安定化作用とともに、空気中の湿度・酸素濃度を低減させることも本発明を具現化する上で好ましく併用できる。 In this case, in addition to the stabilizing action of the deterioration preventing agent, reducing the humidity and oxygen concentration in the air can also be preferably used in combination for realizing the present invention.
　これは、公知の技術として不活性ガスとして窒素やアルゴンの使用、減圧～真空による脱気操作、及び密閉環境下による操作が挙げられ、これら３者の内少なくとも１つの方法を上記安定剤を存在させる方法と併用することができる。 This includes the use of nitrogen or argon as an inert gas as a known technique, a degassing operation under reduced pressure to vacuum, and an operation under a sealed environment, and at least one of these three methods uses the above stabilizer. Can be used in combination with the method of
　光学フィルムが空気中の酸素と接触する確率を低減することにより、該材料の劣化が抑制できるため好ましい。 It is preferable because the deterioration of the material can be suppressed by reducing the probability that the optical film comes into contact with oxygen in the air.
　また、本発明の光学フィルムは、偏光板保護フィルムとしても活用するため、本発明の偏光板及び偏光板を構成する偏光子に対して経時保存性を向上させる観点からも、光学フィルム中における上述の劣化防止剤の存在が重要な役割を担う。 Moreover, since the optical film of the present invention is also used as a polarizing plate protective film, from the viewpoint of improving the storage stability with time with respect to the polarizing plate of the present invention and the polarizer constituting the polarizing plate, the above-mentioned in the optical film. The presence of an anti-degradation agent plays an important role.
　本発明の偏光板を用いた液晶表示装置において、本発明の光学フィルムに上述の劣化防止剤が存在すると、上記の変質や劣化を抑制する観点から光学フィルムの経時保存性が向上できるとともに、液晶表示装置の表示品質向上においても光学的な補償設計が長期にわたって機能発現できる点で優れている。 In the liquid crystal display device using the polarizing plate of the present invention, when the above-mentioned deterioration preventing agent is present in the optical film of the present invention, the storage stability of the optical film over time can be improved from the viewpoint of suppressing the above-mentioned deterioration and deterioration, and the liquid crystal Also in improving the display quality of the display device, the optical compensation design is excellent in that the function can be expressed over a long period of time.
　《酸化防止剤》
　本発明の光学フィルムの基材となる樹脂は、熱だけでなく酸素によっても分解が促進されるため、本発明の光学フィルムにおいては安定化剤として酸化防止剤を含有することが好ましい。 "Antioxidant"
Since the resin used as the base material of the optical film of the present invention is decomposed not only by heat but also by oxygen, the optical film of the present invention preferably contains an antioxidant as a stabilizer.
　特に、溶融製膜が行われるような高温環境下では、フィルム成形材料の熱、及び酸素による分解が促進されるため、酸化防止剤を含有することが好ましい。 In particular, in a high temperature environment where melt film formation is performed, the film molding material is preferably decomposed by heat and oxygen, so that an antioxidant is preferably contained.
　本発明において有用な酸化防止剤としては、酸素によるフィルム成形材料の劣化を抑制する化合物であれば制限なく用いることができるが、中でも有用な酸化防止剤としては、フェノール系化合物、リン系化合物、イオウ系化合物、アクリレート系化合物、ベンゾフラノン系化合物、酸素スカベンジャー等が挙げられ、これらの中でも、特にフェノール系化合物、リン系化合物、アクリレート系化合物、ベンゾフラノン系化合物が好ましい。これらの化合物を配合することにより、透明性、耐熱性等を低下させることなく、熱や熱酸化劣化等による成形体の着色や強度低下を防止できる。これらの酸化防止剤は、それぞれ単独で、或いは２種以上を組み合わせて用いることができる。 The antioxidant useful in the present invention can be used without limitation as long as it is a compound that suppresses deterioration of the film-forming material due to oxygen. Among them, useful antioxidants include phenolic compounds, phosphorus compounds, Sulfur compounds, acrylate compounds, benzofuranone compounds, oxygen scavengers and the like can be mentioned, and among these, phenol compounds, phosphorus compounds, acrylate compounds, and benzofuranone compounds are particularly preferable. By blending these compounds, it is possible to prevent coloration or strength reduction of the molded product due to heat, thermal oxidation deterioration, or the like without reducing transparency, heat resistance, and the like. These antioxidants can be used alone or in combination of two or more.
　（フェノール系化合物）
　本発明において有用な酸化防止剤の一つとして、フェノール系化合物が挙げられる。 (Phenolic compounds)
One antioxidant useful in the present invention is a phenolic compound.
　フェノール系化合物は既知の化合物であり、パラ－ｔ－ブチルフェノール、パラ－（１，１，３，３－テトラメチルブチル）フェノール等のアルキル基置換フェノールの他、例えば、米国特許第４，８３９，４０５号明細書の第１２～１４欄に記載の、２，６－ジアルキルフェノール誘導体化合物、所謂ヒンダードフェノール系化合物が挙げられるが、これらの中で、ヒンダードフェノール系化合物が好ましい。 Phenol compounds are known compounds, and in addition to alkyl group-substituted phenols such as para-t-butylphenol and para- (1,1,3,3-tetramethylbutyl) phenol, for example, US Pat. No. 4,839, Examples include 2,6-dialkylphenol derivative compounds, so-called hindered phenol compounds, described in columns 12 to 14 of the specification of No. 405, and among these, hindered phenol compounds are preferred.
　ヒンダードフェノールフェノール系化合物の具体例としては、ｎ－オクタデシル３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）－プロピオネート、ｎ－オクタデシル３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）－アセテート、ｎ－オクタデシル３，５－ジ－ｔ－ブチル－４－ヒドロキシベンゾエート、ｎ－ヘキシル３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニルベンゾエート、ｎ－ドデシル３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニルベンゾエート、ネオ－ドデシル３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート、ドデシルβ（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート、エチルα－（４－ヒドロキシ－３，５－ジ－ｔ－ブチルフェニル）イソブチレート、オクタデシルα－（４－ヒドロキシ－３，５－ジ－ｔ－ブチルフェニル）イソブチレート、オクタデシルα－（４－ヒドロキシ－３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート、２－（ｎ－オクチルチオ）エチル３，５－ジ－ｔ－ブチル－４－ヒドロキシ－ベンゾエート、２－（ｎ－オクチルチオ）エチル３，５－ジ－ｔ－ブチル－４－ヒドロキシ－フェニルアセテート、２－（ｎ－オクタデシルチオ）エチル３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニルアセテート、２－（ｎ－オクタデシルチオ）エチル３，５－ジ－ｔ－ブチル－４－ヒドロキシ－ベンゾエート、２－（２－ヒドロキシエチルチオ）エチル３，５－ジ－ｔ－ブチル－４－ヒドロキシベンゾエート、ジエチルグリコールビス－（３，５－ジ－ｔ－ブチル－４－ヒドロキシ－フェニル）プロピオネート、２－（ｎ－オクタデシルチオ）エチル３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート、ステアルアミドＮ，Ｎ－ビス－［エチレン３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート］、ｎ－ブチルイミノＮ，Ｎ－ビス－［エチレン３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート］、２－（２－ステアロイルオキシエチルチオ）エチル３，５－ジ－ｔ－ブチル－４－ヒドロキシベンゾエート、２－（２－ステアロイルオキシエチルチオ）エチル７－（３－メチル－５－ｔ－ブチル－４－ヒドロキシフェニル）ヘプタノエート、１，２－プロピレングリコールビス－［３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート］、エチレングリコールビス－［３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート］、ネオペンチルグリコールビス－［３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート］、エチレングリコールビス－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニルアセテート）、グリセリン－ｌ－ｎ－オクタデカノエート－２，３－ビス－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニルアセテート）、ペンタエリスリトール－テトラキス－［３－（３′，５′－ジ－ｔ－ブチル－４′－ヒドロキシフェニル）プロピオネート］、３，９－ビス－｛２－〔３－（３－ｔｅｒｔ－ブチル－４－ヒドロキシ－５－メチルフェニル）プロピオニルオキシ〕－１，１－ジメチルエチル｝－２，４，８，１０－テトラオキサスピロ〔５．５〕ウンデカン、１，１，１－トリメチロールエタン－トリス－［３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート］、ソルビトールヘキサ－［３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート］、２－ヒドロキシエチル７－（３－メチル－５－ｔブチル－４－ヒドロキシフェニル）プロピオネート、２－ステアロイルオキシエチル７－（３－メチル－５－ｔ－ブチル－４－ヒドロキシフェニル）ヘプタノエート、１，６－ｎ－ヘキサンジオール－ビス［（３′，５′－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオネート］、ペンタエリスリトール－テトラキス（３，５－ジ－ｔ－ブチル－４－ヒドロキシヒドロシンナメート）が含まれる。 Specific examples of the hindered phenol phenol compound include n-octadecyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) -propionate, n-octadecyl 3- (3,5-di-t- Butyl-4-hydroxyphenyl) -acetate, n-octadecyl 3,5-di-t-butyl-4-hydroxybenzoate, n-hexyl 3,5-di-t-butyl-4-hydroxyphenylbenzoate, n-dodecyl 3,5-di-t-butyl-4-hydroxyphenylbenzoate, neo-dodecyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, dodecyl β (3,5-di-t- Butyl-4-hydroxyphenyl) propionate, ethyl α- (4-hydroxy-3,5-di-t-butylphenyl) isobut Tyrate, octadecyl α- (4-hydroxy-3,5-di-t-butylphenyl) isobutyrate, octadecyl α- (4-hydroxy-3,5-di-t-butyl-4-hydroxyphenyl) propionate, 2- (N-octylthio) ethyl 3,5-di-t-butyl-4-hydroxy-benzoate, 2- (n-octylthio) ethyl 3,5-di-t-butyl-4-hydroxy-phenyl acetate, 2- ( n-octadecylthio) ethyl 3,5-di-t-butyl-4-hydroxyphenyl acetate, 2- (n-octadecylthio) ethyl 3,5-di-t-butyl-4-hydroxy-benzoate, 2- ( 2-hydroxyethylthio) ethyl 3,5-di-t-butyl-4-hydroxybenzoate, diethyl glycol bis- (3,5- Di-t-butyl-4-hydroxy-phenyl) propionate, 2- (n-octadecylthio) ethyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, stearamide N, N-bis- [Ethylene 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], n-butylimino N, N-bis- [ethylene 3- (3,5-di-t-butyl-4-hydroxy Phenyl) propionate], 2- (2-stearoyloxyethylthio) ethyl 3,5-di-t-butyl-4-hydroxybenzoate, 2- (2-stearoyloxyethylthio) ethyl 7- (3-methyl-5 -T-butyl-4-hydroxyphenyl) heptanoate, 1,2-propylene glycol bis- [3- (3,5-di-t-butyl 4-hydroxyphenyl) propionate], ethylene glycol bis- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], neopentyl glycol bis- [3- (3,5-di-t -Butyl-4-hydroxyphenyl) propionate], ethylene glycol bis- (3,5-di-t-butyl-4-hydroxyphenyl acetate), glycerin-1-n-octadecanoate-2,3-bis- (3,5-di-t-butyl-4-hydroxyphenyl acetate), pentaerythritol-tetrakis- [3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate], 3, 9-bis- {2- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy] 1,1-dimethylethyl} -2,4,8,10-tetraoxaspiro [5.5] undecane, 1,1,1-trimethylolethane-tris- [3- (3,5-di-t- Butyl-4-hydroxyphenyl) propionate], sorbitol hexa- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2-hydroxyethyl 7- (3-methyl-5-tbutyl -4-hydroxyphenyl) propionate, 2-stearoyloxyethyl 7- (3-methyl-5-tert-butyl-4-hydroxyphenyl) heptanoate, 1,6-n-hexanediol-bis [(3 ', 5' -Di-t-butyl-4-hydroxyphenyl) propionate], pentaerythritol-tetrakis (3,5-di-t-butyl-4-hydroxy) Cihydrocinnamate).
　上記タイプのフェノール化合物は、例えば、チバ・ジャパン株式会社から、“ＩＲＧＡＮＯＸ１０７６”及び“ＩＲＧＡＮＯＸ１０１０”、住友化学株式会社から、“ＳｕｍｉｌｉｚｅｒＧＡ－８０”という商品名で市販されている。 The above type of phenolic compounds are commercially available from Ciba Japan, for example, under the trade names “IRGANOX1076” and “IRGANOX1010” and from Sumitomo Chemical Co., Ltd. under the name “Sumizer GA-80”.
　（リン系化合物）
　本発明において有用なリン系化合物として、ホスファイト系化合物、及びホスホナイト系化合物が好ましく挙げられる。ホスファイト系化合物の具体例としては、トリフェニルホスファイト、ジフェニルイソデシルホスファイト、フェニルジイソデシルホスファイト、トリス（ノニルフェニル）ホスファイト、トリス（ジノニルフェニル）ホスファイト、トリス（２，４－ジ－ｔ－ブチルフェニル）ホスファイト、トリス（２，４－ジ－ｔ－ブチル－５－メチルフェニル）ホスファイト、１０－（３，５－ジ－ｔ－ブチル－４－ヒドロキシベンジル）－９，１０－ジヒドロ－９－オキサ－１０－ホスファフェナントレン－１０－オキサイド、６－［３－（３－ｔ－ブチル－４－ヒドロキシ－５－メチルフェニル）プロポキシ］－２，４，８，１０－テトラ－ｔ－ブチルジベンズ［ｄ，ｆ］［１，３，２］ジオキサホスフェピン、トリデシルホスファイト等のモノホスファイト系化合物；４，４′－ブチリデン－ビス（３－メチル－６－ｔ－ブチルフェニル－ジ－トリデシルホスファイト）、４，４′－イソプロピリデン－ビス（フェニル－ジ－アルキル（Ｃ１２～Ｃ１５）ホスファイト）等のジホスファイト系化合物；等が挙げられる。上記タイプのホスファイト系化合物は、例えば、住友化学株式会社から、“ＳｕｍｉｌｉｚｅｒＧＰ”、株式会社ＡＤＥＫＡから“ＡＤＫ　ＳＴＡＢ　ＰＥＰ－２４Ｇ”、“ＡＤＫ　ＳＴＡＢ　ＰＥＰ－３６”、“ＡＤＫ　ＳＴＡＢ　３０１０”、“ＡＤＫ　ＳＴＡＢ　ＨＰ－１０”及び“ＡＤＫ　ＳＴＡＢ　２１１２”という商品名で市販されている。 (Phosphorus compounds)
Preferred phosphorus compounds useful in the present invention include phosphite compounds and phosphonite compounds. Specific examples of the phosphite compound include triphenyl phosphite, diphenylisodecyl phosphite, phenyl diisodecyl phosphite, tris (nonylphenyl) phosphite, tris (dinonylphenyl) phosphite, tris (2,4-diphenyl). -T-butylphenyl) phosphite, tris (2,4-di-t-butyl-5-methylphenyl) phosphite, 10- (3,5-di-t-butyl-4-hydroxybenzyl) -9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 6- [3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propoxy] -2,4,8,10- Mono, such as tetra-t-butyldibenz [d, f] [1,3,2] dioxaphosphine, tridecyl phosphite 4,4'-butylidene-bis (3-methyl-6-t-butylphenyl-di-tridecyl phosphite), 4,4'-isopropylidene-bis (phenyl-di-alkyl (C12- And diphosphite compounds such as C15) phosphite). The above type of phosphite compounds are, for example, “Sumilizer GP” from Sumitomo Chemical Co., Ltd., “ADK STAB PEP-24G”, “ADK STAB PEP-36”, “ADK STAB 3010”, “ADK STAB” from ADEKA Co., Ltd. It is commercially available under the trade names “HP-10” and “ADK STAB 2112”.
　ホスホナイト系化合物の具体例としては、ジメチル－フェニルホスホナイト、ジ－ｔ－ブチル－フェニルホスホナイト、ジフェニル－フェニルホスホナイト、ジ－（４－ペンチル－フェニル）－フェニルホスホナイト、ジ－（２－ｔ－ブチル－フェニル）－フェニルホスホナイト、ジ－（２－メチル－３－ペンチル－フェニル）－フェニルホスホナイト、ジ－（２－メチル－４－オクチル－フェニル）－フェニルホスホナイト、ジ－（３－ブチル－４－メチル－フェニル）－フェニルホスホナイト、ジ－（３－ヘキシル－４－エチル－フェニル）－フェニルホスホナイト、ジ－（２，４，６－トリメチルフェニル）－フェニルホスホナイト、ジ－（２，３－ジメチル－４－エチル－フェニル）－フェニルホスホナイト、ジ－（２，６－ジエチル－３－ブチルフェニル）－フェニルホスホナイト、ジ－（２，３－ジプロピル－５－ブチルフェニル）－フェニルホスホナイト、ジ－（２，４，６－トリ－ｔ－ブチルフェニル）－フェニルホスホナイト、ビス（２，４－ジ－ｔ－ブチル－５－メチルフェニル）ビフェニル－４－イル－ホスホナイト、ビス（２，４－ジ－ｔ－ブチル－５－メチルフェニル）－４′－（ビス（２，４－ジ－ｔ－ブチル－５－メチルフェノキシ）ホスフィノ）ビフェニル－４－イル－ホスホナイト、テトラキス（２，４－ジ－ｔ－ブチル－フェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，５－ジ－ｔ－ブチル－フェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（３，５－ジ－ｔ－ブチル－フェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，３，４－トリメチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，３－ジメチル－５－エチル－フェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，３－ジメチル－４－プロピルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，３－ジメチル－５－ｔ－ブチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，５－ジメチル－４－ｔ－ブチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，３－ジエチル－５－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，６－ジエチル－４－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，４，５－トリエチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，６－ジエチル－４－プロピルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，５－ジエチル－６－ブチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，３－ジエチル－５－ｔ－ブチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，５－ジエチル－６－ｔ－ブチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，３－ジプロピル－５－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，６－ジプロピル－４－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，６－ジプロピル－５－エチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，３－ジプロピル－６－ブチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，６－ジプロピル－５－ブチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，３－ジブチル－４－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，５－ジブチル－３－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，６－ジブチル－４－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，４－ジ－ｔ－ブチル－３－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，４－ジ－ｔ－ブチル－５－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，４－ジ－ｔ－ブチル－６－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，５－ジ－ｔ－ブチル－３－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，５－ジ－ｔ－ブチル－４－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，５－ジ－ｔ－ブチル－６－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，６－ジ－ｔ－ブチル－３－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，６－ジ－ｔ－ブチル－４－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，６－ジ－ｔ－ブチル－５－メチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，３－ジブチル－４－エチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，４－ジブチル－３－エチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，５－ジブチル－４－エチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，４－ジ－ｔ－ブチル－３－エチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，４－ジ－ｔ－ブチル－５－エチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，４－ジ－ｔ－ブチル－６－エチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，５－ジ－ｔ－ブチル－３－エチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，５－ジ－ｔ－ブチル－４－エチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，５－ジ－ｔ－ブチル－６－エチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，６－ジ－ｔ－ブチル－３－エチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，６－ジ－ｔ－ブチル－４－エチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，６－ジ－ｔ－ブチル－５－エチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，３，４－トリブチルフェニル）－４，４′－ビフェニレンジホスホナイト、テトラキス（２，４，６－トリ－ｔ－ブチルフェニル）－４，４′－ビフェニレンジホスホナイト等が挙げられる。上記タイプのリン系化合物は、例えば、チバ・ジャパン株式会社から“ＩＲＧＡＦＯＳ　Ｐ－ＥＰＱ”、堺化学工業株式会社から“ＧＳＹ－Ｐ１０１”という商品名で市販されている。 Specific examples of the phosphonite compound include dimethyl-phenyl phosphonite, di-t-butyl-phenyl phosphonite, diphenyl-phenyl phosphonite, di- (4-pentyl-phenyl) -phenyl phosphonite, di- (2- t-butyl-phenyl) -phenylphosphonite, di- (2-methyl-3-pentyl-phenyl) -phenylphosphonite, di- (2-methyl-4-octyl-phenyl) -phenylphosphonite, di- ( 3-butyl-4-methyl-phenyl) -phenylphosphonite, di- (3-hexyl-4-ethyl-phenyl) -phenylphosphonite, di- (2,4,6-trimethylphenyl) -phenylphosphonite, Di- (2,3-dimethyl-4-ethyl-phenyl) -phenylphosphonite, di- (2,6-die 3-butylphenyl) -phenylphosphonite, di- (2,3-dipropyl-5-butylphenyl) -phenylphosphonite, di- (2,4,6-tri-t-butylphenyl) -phenylphospho Knight, bis (2,4-di-t-butyl-5-methylphenyl) biphenyl-4-yl-phosphonite, bis (2,4-di-t-butyl-5-methylphenyl) -4 '-(bis (2,4-di-t-butyl-5-methylphenoxy) phosphino) biphenyl-4-yl-phosphonite, tetrakis (2,4-di-t-butyl-phenyl) -4,4'-biphenylenediphosphonite Tetrakis (2,5-di-t-butyl-phenyl) -4,4'-biphenylenediphosphonite, tetrakis (3,5-di-t-butyl-phenyl) -4,4'-bi Enylene diphosphonite, tetrakis (2,3,4-trimethylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,3-dimethyl-5-ethyl-phenyl) -4,4'-biphenylenedi Phosphonite, tetrakis (2,3-dimethyl-4-propylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,3-dimethyl-5-t-butylphenyl) -4,4'-biphenylenedi Phosphonite, tetrakis (2,5-dimethyl-4-tert-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,3-diethyl-5-methylphenyl) -4,4'-biphenylenedi Phosphonite, tetrakis (2,6-diethyl-4-methylphenyl) -4,4'-biphenylenediphosphonite, tetra Kis (2,4,5-triethylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,6-diethyl-4-propylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2, 5-diethyl-6-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,3-diethyl-5-t-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2, 5-diethyl-6-t-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,3-dipropyl-5-methylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2, 6-dipropyl-4-methylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,6-dipropyl-5 Ethylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,3-dipropyl-6-butylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,6-dipropyl-5-butylphenyl) ) -4,4'-biphenylenediphosphonite, tetrakis (2,3-dibutyl-4-methylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,5-dibutyl-3-methylphenyl)- 4,4'-biphenylenediphosphonite, tetrakis (2,6-dibutyl-4-methylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,4-di-t-butyl-3-methylphenyl) ) -4,4'-biphenylenediphosphonite, tetrakis (2,4-di-t-butyl-5-methylphenyl)- , 4'-biphenylenediphosphonite, tetrakis (2,4-di-t-butyl-6-methylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,5-di-t-butyl-3) -Methylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,5-di-t-butyl-4-methylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,5-diphenyl) -T-butyl-6-methylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,6-di-t-butyl-3-methylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,6-di-t-butyl-4-methylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,6-di-t-butyl-5-methylphenyl) ) -4,4'-biphenylenediphosphonite, tetrakis (2,3-dibutyl-4-ethylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,4-dibutyl-3-ethylphenyl)- 4,4'-biphenylenediphosphonite, tetrakis (2,5-dibutyl-4-ethylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,4-di-t-butyl-3-ethylphenyl) ) -4,4'-biphenylenediphosphonite, tetrakis (2,4-di-t-butyl-5-ethylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,4-di-t-) Butyl-6-ethylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,5-di-t-butyl-3-ethylphenyl) -4,4 ' Biphenylene diphosphonite, tetrakis (2,5-di-t-butyl-4-ethylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,5-di-t-butyl-6-ethylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,6-di-t-butyl-3-ethylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,6-di-t-butyl) -4-ethylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,6-di-t-butyl-5-ethylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,3 , 4-tributylphenyl) -4,4'-biphenylenediphosphonite, tetrakis (2,4,6-tri-t-butylphenyl) -4,4'-biphenyle Diphosphonite, and the like. The phosphorus compound of the above type is commercially available, for example, under the trade name “IRGAFOS P-EPQ” from Ciba Japan Co., Ltd. and “GSY-P101” from Sakai Chemical Industry Co., Ltd.
　（イオウ系化合物）
　イオウ系化合物の具体例としては、ジラウリル３，３－チオジプロピオネート、ジミリスチル３，３′－チオジプロピオネート、ジステアリル３，３－チオジプロピオネート、ラウリルステアリル３，３－チオジプロピオネート、ペンタエリスリトール－テトラキス（β－ラウリル－チオ－プロピオネート）、３，９－ビス（２－ドデシルチオエチル）－２，４，８，１０－テトラオキサスピロ［５，５］ウンデカン等が挙げられる。 (Sulfur compounds)
Specific examples of the sulfur compound include dilauryl 3,3-thiodipropionate, dimyristyl 3,3'-thiodipropionate, distearyl 3,3-thiodipropionate, lauryl stearyl 3,3-thiodipropioate. And pentaerythritol-tetrakis (β-lauryl-thio-propionate), 3,9-bis (2-dodecylthioethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane .
　上記タイプのイオウ系化合物は、例えば、住友化学株式会社から、“Ｓｕｍｉｌｉｚｅｒ　ＴＰＬ－Ｒ”及び“Ｓｕｍｉｌｉｚｅｒ　ＴＰ－Ｄ”という商品名で市販されている。 The above-mentioned types of sulfur compounds are commercially available, for example, from Sumitomo Chemical Co., Ltd. under the trade names “Sumilizer TPL-R” and “Sumilizer TP-D”.
　（アクリレート系化合物）
　アクリレート系化合物としては、２－ｔｅｒｔ－ブチル－６－（３－ｔｅｒｔ－ブチル－２－ヒドロキシ－５－メチルベンジル）－４－メチルフェニルアクリレート、２－［１－（２－ヒドロキシ－３、５－ジ－ｔｅｒｔ－ペンチルフェニル）エチル］－４，６－ジ－ｔｅｒｔ－ペンチルフェニルアクリレート等が挙げられる。 (Acrylate compounds)
Examples of the acrylate compound include 2-tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2- [1- (2-hydroxy-3, 5 -Di-tert-pentylphenyl) ethyl] -4,6-di-tert-pentylphenyl acrylate and the like.
　上記タイプのアクリレート系化合物は、例えば、住友化学株式会社から、“ＳｕｍｉｌｉｚｅｒＧＭ”及び“ＳｕｍｉｌｉｚｅｒＧＳ”という商品名で市販されている。 An acrylate compound of the above type is commercially available, for example, from Sumitomo Chemical Co., Ltd. under the trade names “Sumilizer GM” and “Sumilizer GS”.
　（ベンゾフラノン系化合物）
　ベンゾフラノン系化合物としては、３－［４－（２－アセトキシエトキシ）フェニル］－５，７－ジ第三ブチルベンゾフラン－２－オン、５，７－ジ第三ブチル－３－［４－（２－ステアロイルオキシエトキシ）フェニル］ベンゾフラン－２－オン、３，３′－ビス［５，７－ジ第三ブチル－３－（４－［２－ヒドロキシエトキシ］フェニル）ベンゾフラン－２－オン］、５，７－ジ第三ブチル－３－（４－メトキシフェニル）ベンゾフラン－２－オン、５，７－ジ第三ブチル－３－フェニルベンゾフラン－２－オン、５，７－ジ第三ブチル－４－メチル－３－フェニルベンゾフラン－２－オン、３－（４－アセトキシ－３，５－ジメチルフェニル）－５，７－ジ第三ブチルベンゾフラン－２－オン、３－（３，５－ジメチル－４－ピバロイルオキシフェニル）－５，７－ジ第三ブチルベンゾフラン－２－オン、３－（３，４－ジメチルフェニル）－５，７－ジ第三ブチルベンゾフラン－２－オン、３－（２，３－ジメチルフェニル）－５，７－ジ第三ブチル－ベンゾフラン－２－オン等が挙げられる。 (Benzofuranone compounds)
Examples of benzofuranone compounds include 3- [4- (2-acetoxyethoxy) phenyl] -5,7-ditert-butylbenzofuran-2-one and 5,7-ditert-butyl-3- [4- (2 -Stearoyloxyethoxy) phenyl] benzofuran-2-one, 3,3'-bis [5,7-ditert-butyl-3- (4- [2-hydroxyethoxy] phenyl) benzofuran-2-one], 5 , 7-ditert-butyl-3- (4-methoxyphenyl) benzofuran-2-one, 5,7-ditert-butyl-3-phenylbenzofuran-2-one, 5,7-ditert-butyl-4 -Methyl-3-phenylbenzofuran-2-one, 3- (4-acetoxy-3,5-dimethylphenyl) -5,7-ditert-butylbenzofuran-2-one, 3- (3,5-dimethyl- 4-Pivalloy Oxyphenyl) -5,7-ditert-butylbenzofuran-2-one, 3- (3,4-dimethylphenyl) -5,7-ditert-butylbenzofuran-2-one, 3- (2,3- Dimethylphenyl) -5,7-ditert-butyl-benzofuran-2-one and the like.
　上記タイプのベンゾフラノン系化合物は、例えば、チバ・ジャパン株式会社から“ＨＰ－１３６”という商品名で市販されている。 The above-mentioned type of benzofuranone-based compound is commercially available, for example, from Ciba Japan under the trade name “HP-136”.
　（その他の酸化防止剤）
　特公平０８－２７５０８号記載の３，４－ジヒドロ－２Ｈ－１－ベンゾピラン系化合物、３，３′－スピロジクロマン系化合物、１，１－スピロインダン系化合物、モルホリン、チオモルホリン、チオモルホリンオキシド、チオモルホリンジオキシド、ピペラジン骨格を部分構造に有する化合物、特開平３－１７４１５０号記載のジアルコキシベンゼン系化合物等の酸素スカベンジャー等が挙げられる。 (Other antioxidants)
3,4-dihydro-2H-1-benzopyran compounds, 3,3′-spirodichroman compounds, 1,1-spiroindane compounds, morpholine, thiomorpholine, thiomorpholine oxide described in JP-B-08-27508, Examples include thiomorpholine dioxide, compounds having a piperazine skeleton in the partial structure, and oxygen scavengers such as dialkoxybenzene compounds described in JP-A-3-174150.
　以上のように説明してきた酸化防止剤の部分構造が、ポリマーの一部、或いは規則的にポリマーへペンダントされていても良い。 The partial structure of the antioxidant described above may be pendant on a part of the polymer or regularly on the polymer.
　酸化防止剤は、前述のセルロースエステル同様に、製造時から持ち越される、或いは保存中に発生する残留酸、無機塩、有機低分子等の不純物を除去することが好ましく、より好ましくは純度９９％以上である。残留酸及び水としては、０．０１～１００ｐｐｍであることが好ましく、セルロースエステルを溶融製膜する上で、熱劣化を抑制でき、製膜安定性、フィルムの光学物性、機械物性が向上する。 The antioxidant is preferably removed from impurities such as residual acids, inorganic salts, organic low molecules, etc. that are carried over from production or generated during storage, and more preferably has a purity of 99% or more, like the cellulose ester described above. It is. The residual acid and water are preferably 0.01 to 100 ppm, and when melt-forming the cellulose ester, thermal deterioration can be suppressed, and the film-forming stability, the optical properties and mechanical properties of the film are improved.
　本発明においては、これらの酸化防止剤は、樹脂に対して各々０．０１～１０質量％添加することが好ましく、更に０．０５～５質量％添加することが好ましく、更に０．１～２質量％添加することが好ましい。 In the present invention, these antioxidants are each preferably added in an amount of 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, and further preferably 0.1 to 2%, based on the resin. It is preferable to add mass%.
　これらの酸化防止剤は、一種のみを用いるよりも数種の異なった系の化合物を併用することで相乗効果を得ることができる。例えば、フェノール系化合物、金属原子を有しないリン系化合物、アクリレート系化合物、ベンゾフラノン系化合物の併用は好ましい。 These antioxidants can obtain a synergistic effect by using several different types of compounds in combination rather than using only one kind. For example, the combined use of a phenol compound, a phosphorus compound having no metal atom, an acrylate compound, and a benzofuranone compound is preferable.
　本発明において好ましい態様のセルロースエステルは、貧溶媒による懸濁洗浄時に酸化防止剤存在下で洗浄することも好ましい。 In a preferred embodiment of the present invention, the cellulose ester is preferably washed in the presence of an antioxidant during suspension washing with a poor solvent.
　使用される酸化防止剤は、セルロースエステルに発生したラジカルを不活性化する、或いはセルロースエステルに発生したラジカルに酸素が付加したことが起因のセルロースエステルの劣化を抑制する化合物であれば制限なく用いることができる。 The antioxidant to be used is not limited as long as it is a compound that inactivates radicals generated in the cellulose ester or suppresses deterioration of the cellulose ester caused by addition of oxygen to the radical generated in the cellulose ester. be able to.
　セルロースエステルの懸濁洗浄に使用する酸化防止剤は、洗浄後セルロースエステル中に残存していてもよい。残存量は０．０１～２０００ｐｐｍがよく、より好ましくは０．０５～１０００ｐｐｍである。更に好ましくは０．１～１００ｐｐｍである。 The antioxidant used for suspension washing of the cellulose ester may remain in the cellulose ester after washing. The residual amount is preferably 0.01 to 2000 ppm, more preferably 0.05 to 1000 ppm. More preferably, it is 0.1 to 100 ppm.
　酸化防止剤は、前述のセルロースエステル同様に、製造時から持ち越される、或いは保存中に発生する残留酸、無機塩、有機低分子等の不純物を除去することが好ましく、より好ましくは純度９９％以上である。残留酸及び水としては、０．０１～１００ｐｐｍであることが好ましく、セルロースエステルを溶融流延製膜する上で、熱劣化を抑制でき、製膜安定性、フィルムの光学物性、機械物性が向上する。 The antioxidant is preferably removed from impurities such as residual acids, inorganic salts, organic low molecules, etc. that are carried over from production or generated during storage, and more preferably has a purity of 99% or more, like the cellulose ester described above. It is. Residual acid and water are preferably 0.01 to 100 ppm, and when melt casting film formation of cellulose ester, thermal deterioration can be suppressed, and film formation stability, optical properties and mechanical properties of the film are improved. To do.
　《ヒンダードアミン光安定剤》
　本発明において、光学フィルムの熱溶融時の劣化防止剤、また製造後に偏光子保護フィルムとして晒される外光や液晶ディスプレイのバックライトからの光に対する劣化防止剤として、ヒンダードアミン光安定剤（ＨＡＬＳ）化合物が挙げられ、これは既知の化合物であり、例えば、米国特許第４，６１９，９５６号明細書の第５～１１欄及び米国特許第４，８３９，４０５号明細書の第３～５欄に記載されているように、２，２，６，６－テトラアルキルピペリジン化合物、またはそれらの酸付加塩もしくはそれらと金属化合物との錯体が含まれる。 《Hindered amine light stabilizer》
In the present invention, a hindered amine light stabilizer (HALS) compound is used as an anti-deterioration agent during thermal melting of an optical film, and as an anti-degradation agent against external light exposed as a polarizer protective film after production and light from a backlight of a liquid crystal display. Which are known compounds, for example, in columns 5-11 of US Pat. No. 4,619,956 and columns 3-5 of US Pat. No. 4,839,405. As described, 2,2,6,6-tetraalkylpiperidine compounds, or acid addition salts thereof or complexes of them with metal compounds are included.
　ヒンダードアミン光安定剤の具体例としては、ビス（２，２，６，６－テトラメチル－４－ピペリジル）セバケート、ビス（２，２，６，６－テトラメチル－４－ピペリジル）スクシネート、ビス（１，２，２，６，６－ペンタメチル－４－ピペリジル）セバケート、ビス（Ｎ－オクトキシ－２，２，６，６－テトラメチル－４－ピペリジル）セバケート、ビス（Ｎ－ベンジルオキシ－２，２，６，６－テトラメチル－４－ピペリジル）セバケート、ビス（Ｎ－シクロヘキシルオキシ－２，２，６，６－テトラメチル－４－ピペリジル）セバケート、ビス（１，２，２，６，６－ペンタメチル－４－ピペリジル）２－（３，５－ジ－ｔ－ブチル－４－ヒドロキシベンジル）－２－ブチルマロネート、ビス（１－アクロイル－２，２，６，６－テトラメチル－４－ピペリジル）２，２－ビス（３，５－ジ－ｔ－ブチル－４－ヒドロキシベンジル）－２－ブチルマロネート、ビス（１，２，２，６，６－ペンタメチル－４－ピペリジル）デカンジオエート、２，２，６，６－テトラメチル－４－ピペリジルメタクリレート、４－［３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオニルオキシ］－１－［２－（３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオニルオキシ）エチル］－２，２，６，６－テトラメチルピペリジン、２－メチル－２－（２，２，６，６－テトラメチル－４－ピペリジル）アミノ－Ｎ－（２，２，６，６－テトラメチル－４－ピペリジル）プロピオンアミド、テトラキス（２，２，６，６－テトラメチル－４－ピペリジル）１，２，３，４－ブタンテトラカルボキシレート、テトラキス（１，２，２，６，６－ペンタメチル－４－ピペリジル）１，２，３，４－ブタンテトラカルボキシレート等が挙げられる。 Specific examples of hindered amine light stabilizers include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (2,2,6,6-tetramethyl-4-piperidyl) succinate, bis ( 1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (N-octoxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (N-benzyloxy-2, 2,6,6-tetramethyl-4-piperidyl) sebacate, bis (N-cyclohexyloxy-2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6) -Pentamethyl-4-piperidyl) 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-butylmalonate, bis (1-acryloyl-2,2,6,6) Tetramethyl-4-piperidyl) 2,2-bis (3,5-di-t-butyl-4-hydroxybenzyl) -2-butylmalonate, bis (1,2,2,6,6-pentamethyl-4 -Piperidyl) decandioate, 2,2,6,6-tetramethyl-4-piperidyl methacrylate, 4- [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy] -1- [2- (3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxy) ethyl] -2,2,6,6-tetramethylpiperidine, 2-methyl-2- (2,2 , 6,6-tetramethyl-4-piperidyl) amino-N- (2,2,6,6-tetramethyl-4-piperidyl) propionamide, tetrakis (2,2,6,6-tetramethyl-4- Piperidi ) 1,2,3,4-butane tetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) 1,2,3,4-butane tetracarboxylate, and the like.
　また、高分子タイプの化合物でもよく、具体例としては、Ｎ，Ｎ′，Ｎ″，Ｎ″′－テトラキス－［４，６－ビス－〔ブチル－（Ｎ－メチル－２，２，６，６－テトラメチルピペリジン－４－イル）アミノ〕－トリアジン－２－イル］－４，７－ジアザデカン－１，１０－ジアミン、ジブチルアミンと１，３，５－トリアジン－Ｎ，Ｎ′－ビス（２，２，６，６－テトラメチル－４－ピペリジル）－１，６－ヘキサメチレンジアミンとＮ－（２，２，６，６－テトラメチル－４－ピペリジル）ブチルアミンとの重縮合物、ジブチルアミンと１，３，５－トリアジンとＮ，Ｎ′－ビス（２，２，６，６－テトラメチル－４－ピペリジル）ブチルアミンとの重縮合物、ポリ〔｛（１，１，３，３－テトラメチルブチル）アミノ－１，３，５－トリアジン－２，４－ジイル｝｛（２，２，６，６－テトラメチル－４－ピペリジル）イミノ｝ヘキサメチレン｛（２，２，６，６－テトラメチル－４－ピペリジル）イミノ｝〕、１，６－ヘキサンジアミン－Ｎ，Ｎ′－ビス（２，２，６，６－テトラメチル－４－ピペリジル）とモルホリン－２，４，６－トリクロロ－１，３，５－トリアジンとの重縮合物、ポリ［（６－モルホリノ－ｓ－トリアジン－２，４－ジイル）〔（２，２，６，６－テトラメチル－４－ピペリジル）イミノ〕－ヘキサメチレン〔（２，２，６，６－テトラメチル－４－ピペリジル）イミノ〕］等の、ピペリジン環がトリアジン骨格を介して複数結合した高分子量ＨＡＬＳ；コハク酸ジメチルと４－ヒドロキシ－２，２，６，６－テトラメチル－１－ピペリジンエタノールとの重合物、１，２，３，４－ブタンテトラカルボン酸と１，２，２，６，６－ペンタメチル－４－ピペリジノールと３，９－ビス（２－ヒドロキシ－１，１－ジメチルエチル）－２，４，８，１０－テトラオキサスピロ［５，５］ウンデカンとの混合エステル化物等の、ピペリジン環がエステル結合を介して結合した化合物等が挙げられるが、これらに限定されるものではない。 Further, it may be a polymer type compound. Specific examples include N, N ′, N ″, N ″ ′-tetrakis- [4,6-bis- [butyl- (N-methyl-2,2,6, 6-tetramethylpiperidin-4-yl) amino] -triazin-2-yl] -4,7-diazadecane-1,10-diamine, dibutylamine and 1,3,5-triazine-N, N′-bis ( 2,2,6,6-tetramethyl-4-piperidyl) -1,6-hexamethylenediamine and N- (2,2,6,6-tetramethyl-4-piperidyl) butylamine polycondensate, di Polycondensate of butylamine, 1,3,5-triazine and N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) butylamine, poly [{(1,1,3,3 -Tetramethylbutyl) amino-1,3,5-to Azine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2,2,6,6-tetramethyl-4-piperidyl) imino}], Weight of 1,6-hexanediamine-N, N'-bis (2,2,6,6-tetramethyl-4-piperidyl) and morpholine-2,4,6-trichloro-1,3,5-triazine Condensate, poly [(6-morpholino-s-triazine-2,4-diyl) [(2,2,6,6-tetramethyl-4-piperidyl) imino] -hexamethylene [(2,2,6, 6-tetramethyl-4-piperidyl) imino]] and other high molecular weight HALS in which a plurality of piperidine rings are bonded via a triazine skeleton; dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1 -Piperidine eta 1,2,3,4-butanetetracarboxylic acid, 1,2,2,6,6-pentamethyl-4-piperidinol and 3,9-bis (2-hydroxy-1,1- (Dimethylethyl) -2,4,8,10-tetraoxaspiro [5,5] undecane and the like, and the like include compounds in which piperidine rings are bonded via an ester bond. It is not something.
　これらの中でも、ジブチルアミンと１，３，５－トリアジンとＮ，Ｎ′－ビス（２，２，６，６－テトラメチル－４－ピペリジル）ブチルアミンとの重縮合物、ポリ〔｛（１，１，３，３－テトラメチルブチル）アミノ－１，３，５－トリアジン－２，４－ジイル｝｛（２，２，６，６－テトラメチル－４－ピペリジル）イミノ｝ヘキサメチレン｛（２，２，６，６－テトラメチル－４－ピペリジル）イミノ｝〕、コハク酸ジメチルと４－ヒドロキシ－２，２，６，６－テトラメチル－１－ピペリジンエタノールとの重合物等で、数平均分子量（Ｍｎ）が２，０００～５，０００のものが好ましい。 Among these, polycondensates of dibutylamine, 1,3,5-triazine and N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) butylamine, poly [{(1, 1,3,3-tetramethylbutyl) amino-1,3,5-triazine-2,4-diyl} {(2,2,6,6-tetramethyl-4-piperidyl) imino} hexamethylene {(2 , 2,6,6-tetramethyl-4-piperidyl) imino}], a polymer of dimethyl succinate and 4-hydroxy-2,2,6,6-tetramethyl-1-piperidineethanol, etc. A molecular weight (Mn) of 2,000 to 5,000 is preferred.
　上記タイプのヒンダードアミン化合物は、例えば、チバ・ジャパン株式会社から、“ＴＩＮＵＶＩＮ１４４”及び“ＴＩＮＵＶＩＮ７７０”、株式会社ＡＤＥＫＡから“ＡＤＫ　ＳＴＡＢ　ＬＡ－５２”という商品名で市販されている。 Hindered amine compounds of the above type are commercially available, for example, from Ciba Japan Co., Ltd. under the trade names “TINUVIN 144” and “TINUVIN 770” and from ADEKA Co., Ltd. under the name “ADK STAB LA-52”.
　本発明においては、ヒンダードアミン光安定剤は、本発明に係るセルロースエステルの質量に対して、０．１～１０質量％添加することが好ましく、更に０．２～５質量％添加することが好ましく、更に０．５～２質量％添加することが好ましい。これらは２種以上を併用してもよい。 In the present invention, the hindered amine light stabilizer is preferably added in an amount of 0.1 to 10% by mass, more preferably 0.2 to 5% by mass, based on the mass of the cellulose ester according to the present invention. Further, it is preferable to add 0.5 to 2% by mass. Two or more of these may be used in combination.
　《酸捕捉剤》
　セルロースエステルは、溶融製膜が行われるような高温環境下では酸によっても分解が促進されるため、本発明の光学フィルムにおいては劣化防止剤として酸捕捉剤を含有することが好ましい。 <Acid scavenger>
The cellulose ester is preferably decomposed by an acid in a high temperature environment in which melt film formation is performed. Therefore, the optical film of the present invention preferably contains an acid scavenger as a deterioration preventing agent.
　本発明において有用な酸捕捉剤としては、酸と反応して酸を不活性化する化合物であれば制限なく用いることができるが、中でも米国特許第４，１３７，２０１号明細書に記載されているような、エポキシ基を有する化合物が好ましい。 Any acid scavenger useful in the present invention can be used without limitation as long as it is a compound that reacts with an acid to inactivate the acid, and is described in U.S. Pat. No. 4,137,201. A compound having an epoxy group is preferred.
　このような酸捕捉剤としてのエポキシ化合物は当該技術分野において既知であり、種々のポリグリコールのジグリシジルエーテル、特にポリグリコール１モル当たりに約８～４０モルのエチレンオキシド等の縮合によって誘導されるポリグリコール、グリセロールのジグリシジルエーテル等、金属エポキシ化合物（例えば、塩化ビニルポリマー組成物において、及び塩化ビニルポリマー組成物と共に、従来から利用されているもの）、エポキシ化エーテル縮合生成物、ビスフェノールＡのジグリシジルエーテル（即ち、４，４′－ジヒドロキシジフェニルジメチルメタン）、エポキシ化不飽和脂肪酸エステル（特に、２～２２個の炭素原子の脂肪酸の４～２個程度の炭素原子のアルキルのエステル（例えば、ブチルエポキシステアレート）等）、及び種々のエポキシ化長鎖脂肪酸トリグリセリド等（例えば、エポキシ化大豆油、エポキシ化亜麻仁油等）の組成物によって代表され例示され得るエポキシ化植物油及び他の不飽和天然油（これらはときとしてエポキシ化天然グリセリドまたは不飽和脂肪酸と称され、これらの脂肪酸は一般に１２～２２個の炭素原子を含有している）が含まれる。 Epoxy compounds as such acid scavengers are known in the art and are derived by condensation of various polyglycol diglycidyl ethers, particularly about 8 to 40 moles of ethylene oxide per mole of polyglycol. Glycol, diglycidyl ether of glycerol, etc., metal epoxy compounds (such as those conventionally used in and with vinyl chloride polymer compositions), epoxidized ether condensation products, diphenols of bisphenol A Glycidyl ether (ie, 4,4'-dihydroxydiphenyldimethylmethane), epoxidized unsaturated fatty acid ester (especially an ester of an alkyl of about 4 to 2 carbon atoms of a fatty acid of 2 to 22 carbon atoms (eg Butyl epoxy stearate) ), And epoxidized vegetable oils and other unsaturated natural oils, which may be represented and exemplified by compositions of various epoxidized long chain fatty acid triglycerides and the like (eg, epoxidized soybean oil, epoxidized linseed oil, etc.) Called epoxidized natural glycerides or unsaturated fatty acids, which generally contain 12 to 22 carbon atoms).
　また、市販のエポキシ基含有エポキシド樹脂化合物として、ＥＰＯＮ　８１５Ｃやその他のエポキシ化エーテルオリゴマー縮合生成物も好ましく用いることができる。 Further, as a commercially available epoxy group-containing epoxide resin compound, EPON 815C and other epoxidized ether oligomer condensation products can also be preferably used.
　更に上記以外に用いることが可能な酸捕捉剤としては、オキセタン化合物やオキサゾリン化合物、あるいはアルカリ土類金属の有機酸塩やアセチルアセトナート錯体、特開平５－１９４７８８号公報の段落６８～１０５に記載されているものが含まれる。 Further, acid scavengers that can be used other than the above include oxetane compounds, oxazoline compounds, organic earth salts of alkaline earth metals and acetylacetonate complexes, and paragraphs 68 to 105 of JP-A-5-194788. Is included.
　本発明においては、酸捕捉剤は、本発明に係るセルロースエステルの質量に対して、０．１～１０質量％添加することが好ましく、更に０．２～５質量％添加することが好ましく、更に０．５～２質量％添加することが好ましい。これらは２種以上を併用してもよい。 In the present invention, the acid scavenger is preferably added in an amount of 0.1 to 10% by mass, more preferably 0.2 to 5% by mass, more preferably 0.2% by mass to the mass of the cellulose ester according to the present invention. It is preferable to add 0.5 to 2% by mass. Two or more of these may be used in combination.
　なお酸捕捉剤は、酸掃去剤、酸捕獲剤、酸キャッチャー等と称されることもあるが、本発明においてはこれらの呼称による差異なく用いることができる。 The acid scavenger may be referred to as an acid scavenger, an acid scavenger, an acid catcher, or the like, but can be used in the present invention without any difference due to their names.
　《金属不活性剤》
　金属不活性剤とは、酸化反応において開始剤あるいは触媒として作用する金属イオンを不活性化する化合物を意味し、ヒドラジド系化合物、シュウ酸ジアミド系化合物、トリアゾール系化合物等が挙げられ、例えば、Ｎ，Ｎ′－ビス〔３－（３，５－ジ－ｔ－ブチル－４－ヒドロキシフェニル）プロピオニル〕ヒドラジン、２－ヒドロキシエチルシュウ酸ジアミド、２－ヒドロキシ－Ｎ－（１Ｈ－１，２，４－トリアゾール－３－イル）ベンズアミド、Ｎ－（５－ｔｅｒｔ－ブチル－２－エトキシフェニル）－Ｎ′－（２－エチルフェニル）シュウ酸アミド等が挙げられる。 《Metal deactivator》
The metal deactivator means a compound that inactivates a metal ion that acts as an initiator or a catalyst in an oxidation reaction, and examples thereof include hydrazide compounds, oxalic acid diamide compounds, triazole compounds, and the like. , N'-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine, 2-hydroxyethyl oxalic acid diamide, 2-hydroxy-N- (1H-1,2,4 -Triazol-3-yl) benzamide, N- (5-tert-butyl-2-ethoxyphenyl) -N '-(2-ethylphenyl) oxalic acid amide and the like.
　本発明においては、金属不活性剤は、本発明に係るセルロースエステルの質量に対して、０．０００２～２質量％添加することが好ましく、更に０．０００５～２質量％添加することが好ましく、更に０．００１～１質量％添加することが好ましい。これらは２種以上を併用してもよい。 In the present invention, the metal deactivator is preferably added in an amount of 0.0002 to 2 mass%, more preferably 0.0005 to 2 mass%, based on the mass of the cellulose ester according to the present invention. Further, it is preferable to add 0.001 to 1% by mass. Two or more of these may be used in combination.
　《紫外線吸収剤》
　紫外線吸収剤は、偏光子や表示装置の紫外線に対する劣化防止の観点から、波長３７０ｎｍ以下の紫外線の吸収能に優れており、かつ液晶表示性の観点から、波長４００ｎｍ以上の可視光の吸収が少ないものが好ましい。本発明に用いられる紫外線吸収剤としては、例えば、オキシベンゾフェノン系化合物、ベンゾトリアゾール系化合物、サリチル酸エステル系化合物、ベンゾフェノン系化合物、シアノアクリレート系化合物、ニッケル錯塩系化合物、トリアジン系化合物等を挙げることができるが、ベンゾフェノン系化合物や着色の少ないベンゾトリアゾール系化合物、トリアジン系化合物が好ましい。また、特開平１０－１８２６２１号、同８－３３７５７４号公報記載の紫外線吸収剤、特開平６－１４８４３０号、特開２００３－１１３３１７号公報記載の高分子紫外線吸収剤を用いてもよい。 <Ultraviolet absorber>
The ultraviolet absorber is excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less from the viewpoint of preventing deterioration of the polarizer and the display device with respect to ultraviolet rays, and has little absorption of visible light having a wavelength of 400 nm or more from the viewpoint of liquid crystal display properties. Those are preferred. Examples of the ultraviolet absorber used in the present invention include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, triazine compounds, and the like. However, benzophenone compounds, less colored benzotriazole compounds, and triazine compounds are preferable. Further, ultraviolet absorbers described in JP-A Nos. 10-182621 and 8-337574, and polymer ultraviolet absorbers described in JP-A Nos. 6-148430 and 2003-113317 may be used.
　ベンゾトリアゾール系紫外線吸収剤の具体例として、２－（２′－ヒドロキシ－５′－メチルフェニル）ベンゾトリアゾール、２－（２′－ヒドロキシ－３′，５′－ジ－ｔｅｒｔ－ブチルフェニル）ベンゾトリアゾール、２－（２′－ヒドロキシ－３′－ｔｅｒｔ－ブチル－５′－メチルフェニル）ベンゾトリアゾール、２－（２′－ヒドロキシ－３′，５′－ジ－ｔｅｒｔ－ブチルフェニル）－５－クロロベンゾトリアゾール、２－（２′－ヒドロキシ－３′－（３″，４″，５″，６″－テトラヒドロフタルイミドメチル）－５′－メチルフェニル）ベンゾトリアゾール、２，２－メチレンビス（４－（１，１，３，３－テトラメチルブチル）－６－（２Ｈ－ベンゾトリアゾール－２－イル）フェノール）、２－（２′－ヒドロキシ－３′－ｔｅｒｔ－ブチル－５′－メチルフェニル）－５－クロロベンゾトリアゾール、２－（２′－ヒドロキシ－３′－ｔｅｒｔ－ブチル－５′－（２－オクチルオキシカルボニルエチル）－フェニル）－５－クロロベンゾトリアゾール、２－（２′－ヒドロキシ－３′－（１－メチル－１－フェニルエチル）－５′－（１，１，３，３－テトラメチルブチル）－フェニル）ベンゾトリアゾール、２－（２Ｈ－ベンゾトリアゾール－２－イル）－６－（直鎖及び側鎖ドデシル）－４－メチルフェノール、オクチル－３－〔３－ｔｅｒｔ－ブチル－４－ヒドロキシ－５－（クロロ－２Ｈ－ベンゾトリアゾール－２－イル）フェニル〕プロピオネートと２－エチルヘキシル－３－〔３－ｔｅｒｔ－ブチル－４－ヒドロキシ－５－（５－クロロ－２Ｈ－ベンゾトリアゾール－２－イル）フェニル〕プロピオネートの混合物等を挙げることができるが、これらに限定されない。 Specific examples of benzotriazole ultraviolet absorbers include 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) benzo Triazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5 Chlorobenzotriazole, 2- (2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6 ″ -tetrahydrophthalimidomethyl) -5′-methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2'-hydroxy 3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5 '-(2-octyloxycarbonylethyl) -phenyl)- 5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′-(1-methyl-1-phenylethyl) -5 ′-(1,1,3,3-tetramethylbutyl) -phenyl) benzotriazole, 2- (2H-benzotriazol-2-yl) -6- (linear and side chain dodecyl) -4-methylphenol, octyl-3- [3-tert-butyl-4-hydroxy-5- (chloro-2H -Benzotriazol-2-yl) phenyl] propionate and 2-ethylhexyl-3- [3-tert-butyl-4-hydroxy-5- (5-chloro- H- benzotriazol-2-yl) can be mentioned mixtures of phenyl] propionate, and the like.
　また、市販品として、チヌビン（ＴＩＮＵＶＩＮ）１７１、チヌビン（ＴＩＮＵＶＩＮ）９００、チヌビン（ＴＩＮＵＶＩＮ）９２８、チヌビン（ＴＩＮＵＶＩＮ）３６０（いずれもチバ・ジャパン社製）、ＬＡ３１（株式会社ＡＤＥＫＡ社製）、ＲＵＶＡ－１００（大塚化学製）が挙げられる。 As commercially available products, TINUVIN 171, TINUVIN 900, TINUVIN 928, TINUVIN 360 (all manufactured by Ciba Japan), LA31 (manufactured by ADEKA Corporation), RUVA- 100 (manufactured by Otsuka Chemical).
　ベンゾフェノン系化合物の具体例として、２，４－ジヒドロキシベンゾフェノン、２，２′－ジヒドロキシ－４－メトキシベンゾフェノン、２－ヒドロキシ－４－メトキシ－５－スルホベンゾフェノン、ビス（２－メトキシ－４－ヒドロキシ－５－ベンゾイルフェニルメタン）等を挙げることができるが、これらに限定されるものではない。 Specific examples of benzophenone compounds include 2,4-dihydroxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis (2-methoxy-4-hydroxy-) 5-benzoylphenylmethane) and the like, but are not limited thereto.
　本発明においては、紫外線吸収剤は樹脂に対して０．１～５質量％添加することが好ましく、更に０．２～３質量％添加することが好ましく、更に０．５～２質量％添加することが好ましい。これらは２種以上を併用してもよい。 In the present invention, the ultraviolet absorber is preferably added in an amount of 0.1 to 5% by mass, more preferably 0.2 to 3% by mass, and further 0.5 to 2% by mass based on the resin. It is preferable. Two or more of these may be used in combination.
　またベンゾトリアゾール構造やトリアジン構造が、ポリマーの一部、或いは規則的にポリマーへペンダントされていてもよく、可塑剤、酸化防止剤、酸掃去剤等の他の添加剤の分子構造の一部に導入されていてもよい。 The benzotriazole structure or triazine structure may be part of the polymer, or may be regularly pendant to the polymer, and part of the molecular structure of other additives such as plasticizers, antioxidants, and acid scavengers. May be introduced.
　従来公知の紫外線吸収性ポリマーとしては、特に限定されないが、例えば、ＲＵＶＡ－９３（大塚化学製）を単独重合させたポリマー及びＲＵＶＡ－９３と他のモノマーとを共重合させたポリマー等が挙げられる。具体的には、ＲＵＶＡ－９３とメチルメタクリレートを３：７の比（質量比）で共重合させたＰＵＶＡ－３０Ｍ、５：５の比（質量比）で共重合させたＰＵＶＡ－５０Ｍ等が挙げられる。更に、特開２００３－１１３３１７号公報に記載のポリマー等が挙げられる。 The conventionally known UV-absorbing polymer is not particularly limited, and examples thereof include a polymer obtained by homopolymerizing RUVA-93 (manufactured by Otsuka Chemical) and a polymer obtained by copolymerizing RUVA-93 with other monomers. . Specifically, PUVA-30M obtained by copolymerizing RUVA-93 and methyl methacrylate in a ratio (mass ratio) of 3: 7, and PUVA-50M copolymerized in a ratio of 5: 5 (mass ratio). It is done. Furthermore, the polymer etc. which are described in Unexamined-Japanese-Patent No. 2003-113317 are mentioned.
　《その他の添加剤》
　本発明においては、セルロースエステルに劣化防止剤、可塑剤や紫外線吸収剤の他、種々の添加剤を含有することができる。例えば、マット剤、フィラー、シリカやケイ酸塩等の無機化合物、染料、顔料、蛍光体、二色性色素、リターデーション制御剤、屈折率調整剤、ガス透過抑制剤、抗菌剤、生分解性付与剤などが挙げられる。 《Other additives》
In the present invention, the cellulose ester can contain various additives in addition to the deterioration inhibitor, the plasticizer and the ultraviolet absorber. For example, matting agents, fillers, inorganic compounds such as silica and silicates, dyes, pigments, phosphors, dichroic dyes, retardation control agents, refractive index regulators, gas permeation inhibitors, antibacterial agents, biodegradable Examples include an imparting agent.
　また、上記機能を有するものであれば、これに分類されない添加剤も用いることができる。 Also, additives that are not classified as long as they have the above functions can be used.
　そして、これらの添加剤をセルロースエステルに含有させる方法としては、各々の材料を固体或いは液体のまま混合し、加熱溶融し混練して均一な溶融物とした後、流延して光学フィルムを形成する方法であっても、予め全ての材料を溶媒等を用いて、溶解して均一溶液とした後、溶媒を除去して、添加剤とセルロースエステルの混合物を形成し、これを加熱溶融し、流延して光学フィルムを形成してもよい。 Then, as a method of incorporating these additives into the cellulose ester, each material is mixed in a solid or liquid state, heated and melted and kneaded to form a uniform melt, and then cast to form an optical film. Even in this method, after dissolving all the materials in advance using a solvent or the like to obtain a uniform solution, the solvent is removed to form a mixture of the additive and the cellulose ester, and this is heated and melted. It may be cast to form an optical film.
　（マット剤）
　本発明の光学フィルムは、滑り性や光学的、機械的機能を付与するためにマット剤を添加することができる。マット剤としては、無機化合物の微粒子または有機化合物の微粒子が挙げられる。 (Matting agent)
A matting agent can be added to the optical film of the present invention in order to impart slipperiness, optical and mechanical functions. Examples of the matting agent include inorganic compound fine particles and organic compound fine particles.
　マット剤の形状は、球状、棒状、針状、層状、平板状等の形状のものが好ましく用いられる。マット剤としては、例えば、二酸化ケイ素、二酸化チタン、酸化アルミニウム、酸化ジルコニウム、炭酸カルシウム、カオリン、タルク、焼成ケイ酸カルシウム、水和ケイ酸カルシウム、ケイ酸アルミニウム、ケイ酸マグネシウム、リン酸カルシウム等の金属の酸化物、リン酸塩、ケイ酸塩、炭酸塩等の無機微粒子や架橋高分子微粒子を挙げることができる。 The shape of the matting agent is preferably a spherical shape, rod shape, needle shape, layer shape, flat plate shape or the like. Examples of the matting agent include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, and calcium phosphate. Examples thereof include inorganic fine particles such as oxides, phosphates, silicates, and carbonates, and crosslinked polymer fine particles.
　中でも、二酸化ケイ素がフィルムのヘイズを低くできるので好ましい。 Among these, silicon dioxide is preferable because it can reduce the haze of the film.
　これらの微粒子は有機物により表面処理されていることが、フィルムのヘイズを低下できるため好ましい。 It is preferable that these fine particles are surface-treated with an organic substance because the haze of the film can be reduced.
　表面処理は、ハロシラン類、アルコキシシラン類、シラザン、シロキサン等で行うことが好ましい。微粒子の平均粒径が大きい方が滑り性効果は大きく、反対に平均粒径の小さい方は透明性に優れる。 The surface treatment is preferably performed with halosilanes, alkoxysilanes, silazane, siloxane, or the like. The larger the average particle size of the fine particles, the greater the sliding effect, and the smaller the average particle size, the better the transparency.
　また、微粒子の二次粒子の平均粒径は０．０１～１．０μｍの範囲である。好ましい微粒子の一次粒子の平均粒径は５～５０ｎｍが好ましく、更に好ましくは、７～１４ｎｍである。これらの微粒子は、フィルム中では通常凝集体として存在しフィルム表面に０．０１～１．０μｍの高さの凹凸を生成させるために好ましく用いられる。 Further, the average particle size of the secondary particles of the fine particles is in the range of 0.01 to 1.0 μm. The average particle size of the primary particles of the fine particles is preferably 5 to 50 nm, more preferably 7 to 14 nm. These fine particles are usually present in the film as aggregates, and are preferably used for generating irregularities with a height of 0.01 to 1.0 μm on the film surface.
　二酸化ケイ素の微粒子としては、日本アエロジル（株）製のアエロジル（ＡＥＲＯＳＩＬ）２００、２００Ｖ、３００、Ｒ９７２、Ｒ９７２Ｖ、Ｒ９７４、Ｒ２０２、Ｒ８１２、ＯＸ５０、ＴＴ６００、ＮＡＸ５０等、日本触媒（株）製のＫＥ－Ｐ１０、ＫＥ－Ｐ３０、ＫＥ－Ｐ１００、ＫＥ－Ｐ１５０等を挙げることができ、好ましくはアエロジル２００Ｖ、Ｒ９７２Ｖ、ＮＡＸ５０、ＫＥ－Ｐ３０、ＫＥ－Ｐ１００である。これらの微粒子は２種以上併用してもよい。 As the fine particles of silicon dioxide, Aerosil 200, 200V, 300, R972, R972V, R974, R202, R812, OX50, TT600, NAX50, etc. manufactured by Nippon Aerosil Co., Ltd. are available. P10, KE-P30, KE-P100, KE-P150 and the like can be mentioned. Aerosil 200V, R972V, NAX50, KE-P30 and KE-P100 are preferable. Two or more kinds of these fine particles may be used in combination.
　２種以上併用する場合、任意の割合で混合して使用することができる。平均粒径や材質の異なる微粒子、例えば、アエロジル２００ＶとＲ９７２Ｖを質量比で０．１：９９．９～９９．９：０．１の範囲で使用できる。 When using two or more kinds in combination, they can be mixed and used at an arbitrary ratio. Fine particles having different average particle sizes and materials, for example, Aerosil 200V and R972V can be used in a mass ratio of 0.1: 99.9 to 99.9: 0.1.
　これらのマット剤の添加方法は混練する等によって行うことが好ましい。また、別の形態として予め溶媒に分散したマット剤とセルロースエステル及び／または可塑剤及び／または酸化防止剤及び／または紫外線吸収剤を混合分散させた後、溶媒を揮発または沈殿させた固形物を得て、これをセルロースエステル溶融物の製造過程で用いることが、マット剤がセルロースエステル中で均一に分散できる観点から好ましい。 These matting agents are preferably added by kneading. Further, as another form, after mixing and dispersing a matting agent and cellulose ester and / or a plasticizer and / or an antioxidant and / or an ultraviolet absorber previously dispersed in a solvent, a solid substance obtained by volatilizing or precipitating the solvent is obtained. Obtaining and using this in the manufacturing process of the cellulose ester melt is preferable from the viewpoint that the matting agent can be uniformly dispersed in the cellulose ester.
　上記マット剤は、フィルムの機械的、電気的、光学的特性改善のために添加することもできる。 The matting agent can be added to improve the mechanical, electrical and optical properties of the film.
　なお、これらの微粒子を添加するほど、得られるフィルムの滑り性は向上するが、添加するほどヘイズが上昇するため、含有量は好ましくは０．００１～５質量％が好ましく、より好ましくは０．００５～１質量％であり、更に好ましくは０．０１～０．５質量％である。 The slipperiness of the resulting film is improved as the fine particles are added, but the haze increases as the fine particles are added. Therefore, the content is preferably 0.001 to 5% by mass, more preferably 0.00. 005 to 1% by mass, more preferably 0.01 to 0.5% by mass.
　なお、本発明の光学フィルムとしては、ヘイズ値が好ましくは１．０％未満、より好ましくは０．５％未満である。ヘイズ値はＪＩＳ－Ｋ－７１３６に基づいて測定することができる。 In addition, as an optical film of this invention, haze value becomes like this. Preferably it is less than 1.0%, More preferably, it is less than 0.5%. The haze value can be measured based on JIS-K-7136.
　上述の光学フィルムの保存或いは製膜工程において、空気中の酸素による劣化反応が併発することがある。この場合、上記添加剤の安定化作用とともに、空気中の酸素濃度を低減させる効果を用いることも本発明を具現化する上で併用できる。 In the above-mentioned optical film storage or film formation process, deterioration reactions due to oxygen in the air may occur at the same time. In this case, the effect of reducing the oxygen concentration in the air can be used together with the stabilizing action of the additive in realizing the present invention.
　これは、公知の技術として不活性ガスとして窒素やアルゴンの使用、減圧～真空による脱気操作、及び密閉環境下による操作が挙げられ、これら３者の内少なくとも１つの方法を上記添加剤を存在させる方法と併用することができる。 This includes the use of nitrogen or argon as an inert gas as a known technique, degassing operation under reduced pressure to vacuum, and operation in a sealed environment, and at least one of these three methods uses the above additives. Can be used in combination with the method of
　光学フィルムが空気中の酸素と接触する確率を低減することにより、該材料の劣化が抑制でき、本発明の目的のためには好ましい。 Degradation of the material can be suppressed by reducing the probability that the optical film comes into contact with oxygen in the air, which is preferable for the purpose of the present invention.
　《光学フィルム》
　次に、本発明の光学フィルムの詳細について説明する。 <Optical film>
Next, the details of the optical film of the present invention will be described.
　本発明において光学フィルムとは、液晶ディスプレイ、プラズマディスプレイ、有機ＥＬディスプレイ等の各種表示装置に用いられる機能フィルムのことであり、詳しくは液晶表示装置用の偏光板保護フィルム、位相差フィルム、反射防止フィルム、輝度向上フィルム、ハードコートフィルム、防眩フィルム、帯電防止フィルム、視野角拡大等の光学補償フィルム等を含む。 In this invention, an optical film is a functional film used for various display apparatuses, such as a liquid crystal display, a plasma display, and an organic electroluminescent display. Specifically, it is a polarizing plate protective film for liquid crystal display apparatuses, retardation film, antireflection Films, brightness enhancement films, hard coat films, antiglare films, antistatic films, optical compensation films such as viewing angle expansion, and the like are included.
　本発明の光学フィルムにおいて、本発明のセルロースエステルの他、本発明に係らないセルロースエステル系樹脂、セルロースエーテル系樹脂、ビニル系樹脂（ポリ酢酸ビニル系樹脂、ポリビニルアルコール系樹脂等も含む）、オレフィン系樹脂（ノルボルネン系樹脂、単環の環状オレフィン系樹脂、環状共役ジエン系樹脂、ビニル脂環式炭化水素系樹脂等）、ポリエステル系樹脂（芳香族ポリエステル、脂肪族ポリエステル、もしくはそれらを含む共重合体）、アクリル系樹脂（共重合体も含む）、ポリカーボネート系樹脂、ポリスチレン系樹脂、ポリスルホン系樹脂、ポリアリレート系樹脂等を含有させることができる。セルロースエステル以外の樹脂の含有量としては０．１～３０質量％が好ましい。 In the optical film of the present invention, in addition to the cellulose ester of the present invention, cellulose ester resins, cellulose ether resins, vinyl resins (including polyvinyl acetate resins, polyvinyl alcohol resins, etc.), olefins not related to the present invention, and olefins Resin (norbornene resin, monocyclic olefin resin, cyclic conjugated diene resin, vinyl alicyclic hydrocarbon resin, etc.), polyester resin (aromatic polyester, aliphatic polyester, or co-polymer containing them) Coalescence), acrylic resins (including copolymers), polycarbonate resins, polystyrene resins, polysulfone resins, polyarylate resins, and the like. The content of the resin other than the cellulose ester is preferably 0.1 to 30% by mass.
　本発明の光学フィルムは、偏光板保護フィルム、位相差フィルムに好ましく用いられる。 The optical film of the present invention is preferably used for a polarizing plate protective film and a retardation film.
　《溶融流延法》
　本発明の光学フィルムは、好ましくは溶融流延法により製造される。 <Melt casting method>
The optical film of the present invention is preferably produced by a melt casting method.
　溶融流延法はフィルム製造時の有機溶媒使用量を、大幅に少なくすることができるため、従来の有機溶媒を多量に使用する溶液流延法に比較して、環境適性が大幅に向上したフィルムが得られるため、溶融流延法により、光学フィルムを製造することが好ましい。 Since the melt casting method can significantly reduce the amount of organic solvent used during film production, the film is much more environmentally friendly than conventional solution casting methods that use large amounts of organic solvents. Therefore, it is preferable to produce an optical film by a melt casting method.
　本発明における溶融流延とは、実質的に溶媒を用いずにセルロースエステルが流動性を示す温度まで加熱溶融し、これを用いて製膜する方法であり、例えば流動性のセルロースエステルをダイスから押し出して製膜する方法である。 The melt casting in the present invention is a method in which cellulose ester is heated and melted to a temperature at which the cellulose ester exhibits fluidity substantially without using a solvent, and a film is formed using this. For example, fluid cellulose ester is removed from a die. This is a method of forming a film by extrusion.
　なお溶融セルロースエステルを調製する過程の一部で溶媒を使用してもよいが、フィルム状に成形を行う溶融製膜プロセスにおいては実質的に溶媒を用いずに成形加工する。 In addition, although a solvent may be used in a part of the process of preparing the molten cellulose ester, in the melt film forming process in which the film is formed into a film, the forming process is substantially performed without using the solvent.
　溶融流延による成形法は、更に詳細には、溶融押出成形法、プレス成形法、インフレーション法、射出成形法、ブロー成形法、延伸成形法等に分類できる。これらの中で、機械的強度及び表面精度等に優れる光学フィルムを得るためには、溶融押し出し法が優れている。以下、溶融押し出し法を例にとり、本発明の光学フィルムの製造方法について説明する。 More specifically, the molding method by melt casting can be classified into a melt extrusion molding method, a press molding method, an inflation method, an injection molding method, a blow molding method, a stretch molding method, and the like. Among these, the melt extrusion method is excellent for obtaining an optical film having excellent mechanical strength, surface accuracy, and the like. Hereinafter, the manufacturing method of the optical film of the present invention will be described by taking the melt extrusion method as an example.
　図１は、本発明の光学フィルムの製造方法を実施する装置の１つの実施形態の一例を示す概略フローシート図である。 FIG. 1 is a schematic flow sheet diagram showing an example of one embodiment of an apparatus for carrying out the method for producing an optical film of the present invention.
　図２は、図１の製造装置の要部拡大の一例を示すフローシートである。 FIG. 2 is a flow sheet showing an example of an enlarged main part of the manufacturing apparatus of FIG.
　光学フィルムの製造方法は、セルロース樹脂等の光学フィルム材料を混合した後、押出し機１を用いて、流延ダイ４から第１冷却ロール５上に溶融押し出し、第１冷却ロール５に外接させるとともに、更に、第２冷却ロール７、第３冷却ロール８の合計３本の冷却ロールに順に外接させて、冷却固化して光学フィルム１０とする。 The optical film is produced by mixing an optical film material such as a cellulose resin, and then using the extruder 1 to melt and extrude from the casting die 4 onto the first cooling roll 5 so as to circumscribe the first cooling roll 5. In addition, the optical film 10 is obtained by sequentially circumscribing a total of three cooling rolls, that is, the second cooling roll 7 and the third cooling roll 8, and cooling and solidifying.
　ついで、剥離ロール９によって剥離した光学フィルム１０を、ついで延伸装置１２により光学フィルムの両端部を把持して幅方向に延伸した後、巻取り装置１６により巻き取る。 Next, the optical film 10 peeled off by the peeling roll 9 is then stretched in the width direction by holding both ends of the optical film by the stretching device 12, and then wound by the winding device 16.
　また、平面性を矯正するために溶融フィルムを第１冷却ロール５表面に挟圧するタッチロール６が設けられている。このタッチロール６は表面が弾性を有し、第１冷却ロール５との間でニップを形成している。タッチロール６についての詳細は後述する。 In addition, a touch roll 6 is provided to clamp the molten film on the surface of the first cooling roll 5 in order to correct the flatness. The touch roll 6 has an elastic surface and forms a nip with the first cooling roll 5. Details of the touch roll 6 will be described later.
　光学フィルムの製造方法において、溶融押し出しの条件は、他のポリエステル等の熱可塑性樹脂に用いられる条件と同様にして行うことができる。材料は予め乾燥させておくことが好ましい。真空または減圧乾燥機や除湿熱風乾燥機等で水分を１０００ｐｐｍ以下、好ましくは２００ｐｐｍ以下に乾燥させることが望ましい。 In the method for producing an optical film, the conditions for melt extrusion can be performed in the same manner as the conditions used for other thermoplastic resins such as polyester. The material is preferably dried beforehand. It is desirable to dry the moisture to 1000 ppm or less, preferably 200 ppm or less by using a vacuum or reduced pressure drier or a dehumidifying hot air drier.
　例えば、熱風や真空または減圧下で乾燥したセルロースエステル系樹脂を押出し機１を用いて、押し出し温度２００～３００℃程度で溶融し、リーフディスクタイプのフィルター２等で濾過し、異物を除去する。 For example, a cellulose ester resin dried under hot air, vacuum or reduced pressure is melted at an extrusion temperature of about 200 to 300 ° C. using an extruder 1 and filtered through a leaf disk type filter 2 to remove foreign matters.
　供給ホッパー（図示略）から押出し機１へ導入する際は、真空下または減圧下や不活性ガス雰囲気下にして、酸化分解等を防止することが好ましい。 When introducing into the extruder 1 from a supply hopper (not shown), it is preferable to prevent oxidative decomposition and the like under vacuum, reduced pressure, or inert gas atmosphere.
　可塑剤等の添加剤を予め混合しない場合は、それらを押出し機の途中で練り込んでもよい。均一に添加するために、スタチックミキサー等の混合装置を用いることが好ましい。 When additives such as plasticizer are not mixed in advance, they may be kneaded in the middle of the extruder. In order to add uniformly, it is preferable to use a mixing apparatus such as a static mixer.
　本発明において、セルロース樹脂と、その他必要により添加される安定化剤等の添加剤は、溶融する前に混合しておくことが好ましく、セルロース樹脂と添加剤を加熱前に混合することが更に好ましい。混合は、混合機等により行ってもよく、また、前記したようにセルロース樹脂調製過程において混合してもよい。混合機を使用する場合は、Ｖ型混合機、円錐スクリュー型混合機、水平円筒型混合機等、ヘンシェルミキサー、リボンミキサー等一般的な混合機を用いることができる。 In the present invention, the cellulose resin and other additives such as a stabilizer added as necessary are preferably mixed before melting, and more preferably mixed before heating and the cellulose resin. . Mixing may be performed by a mixer or the like, or may be mixed in the cellulose resin preparation process as described above. When a mixer is used, a general mixer such as a V-type mixer, a conical screw type mixer, a horizontal cylindrical type mixer, a Henschel mixer, a ribbon mixer, or the like can be used.
　上記のように光学フィルム構成材料を混合した後に、その混合物を押出し機１を用いて直接溶融して製膜するようにしてもよいが、一旦、光学フィルム構成材料をペレット化した後、該ペレットを押出し機１で溶融して製膜するようにしてもよい。 After mixing the optical film constituting material as described above, the mixture may be directly melted and formed into a film using the extruder 1, but once the optical film constituting material is pelletized, the pellet May be melted by the extruder 1 to form a film.
　また、光学フィルム構成材料が、融点の異なる複数の材料を含む場合には、融点の低い材料のみが溶融する温度で一旦、いわゆるおこし状の半溶融物を作製し、半溶融物を押出し機１に投入して製膜することも可能である。 Further, when the optical film constituting material includes a plurality of materials having different melting points, a so-called braided semi-melt is once produced at a temperature at which only a material having a low melting point is melted, and the semi-melt is extruded into the extruder 1. It is also possible to form a film by putting it into the film.
　光学フィルム構成材料に熱分解しやすい材料が含まれる場合には、溶融回数を減らす目的で、ペレットを作製せずに直接製膜する方法や、上記のようなおこし状の半溶融物を作ってから製膜する方法が好ましい。 If the optical film material contains materials that are easily pyrolyzed, in order to reduce the number of melting times, a method of directly forming a film without producing pellets, or making a braided semi-melt as described above A method of forming a film from is preferred.
　押出し機１は、市場で入手可能な種々の押出し機を使用可能であるが、溶融混練押出し機が好ましく、単軸押出し機でも２軸押出し機でもよい。 The extruder 1 can use various types of extruders available on the market, but is preferably a melt-kneading extruder, and may be a single screw extruder or a twin screw extruder.
　光学フィルム構成材料からペレットを作製せずに、直接製膜を行う場合、適当な混練度が必要であるため２軸押出し機を用いることが好ましいが、単軸押出し機でも、スクリューの形状をマドック型、ユニメルト、ダルメージ等の混練型のスクリューに変更することにより、適度の混練が得られるので、使用可能である。光学フィルム構成材料として、一旦、ペレットやおこし状の半溶融物を使用する場合は、単軸押出し機でも２軸押出し機でも使用可能である。 When forming a film directly without forming pellets from optical film constituent materials, it is preferable to use a twin-screw extruder because an appropriate degree of kneading is required. However, even with a single-screw extruder, the screw shape can be changed to Maddock. By changing to a kneading type screw such as a mold, unimelt, dalmage, etc., moderate kneading can be obtained, which can be used. When a pellet or braided semi-melt is used as the optical film constituent material, it can be used with either a single screw extruder or a twin screw extruder.
　押出し機１内及び押出した後の冷却工程は、窒素ガス等の不活性ガスで置換するか、あるいは減圧することにより、酸素の濃度を下げることが好ましい。 The cooling step in the extruder 1 and after the extrusion is preferably performed by substituting with an inert gas such as nitrogen gas or reducing the pressure to reduce the oxygen concentration.
　押出し機１内の光学フィルム構成材料の溶融温度は、光学フィルム構成材料の粘度や吐出量、製造するシートの厚み等によって好ましい条件が異なるが、１５０～３００℃が好ましく、１８０～２７０℃がより好ましく、２００～２５０℃が更に好ましい。押出し時の溶融粘度は、１０～１０００００ポイズ、好ましくは１００～１００００ポイズである。また、押出し機１内での光学フィルム構成材料の滞留時間は短い方が好ましく、５分以内、好ましくは３分以内、より好ましくは２分以内である。 The melting temperature of the optical film constituent material in the extruder 1 varies depending on the viscosity and discharge amount of the optical film constituent material, the thickness of the sheet to be manufactured, etc., but is preferably 150 to 300 ° C., more preferably 180 to 270 ° C. 200 to 250 ° C. is more preferable. The melt viscosity at the time of extrusion is 10 to 100,000 poise, preferably 100 to 10,000 poise. Further, the residence time of the optical film constituting material in the extruder 1 is preferably shorter, and is within 5 minutes, preferably within 3 minutes, and more preferably within 2 minutes.
　滞留時間は、押出し機１の種類、押出す条件にも左右されるが、材料の供給量やＬ／Ｄ、スクリュー回転数、スクリューの溝の深さ等を調整することにより短縮することが可能である。 Although the residence time depends on the type of the extruder 1 and the extrusion conditions, it can be shortened by adjusting the material supply amount, L / D, screw rotation speed, screw groove depth, etc. It is.
　押出し機１のスクリューの形状や回転数等は、光学フィルム構成材料の粘度や吐出量等により適宜選択される。本発明において押出し機１でのせん断速度は、１／秒～１００００／秒、好ましくは５／秒～１０００／秒、より好ましくは１０／秒～１００／秒である。 The screw shape, rotation speed, and the like of the extruder 1 are appropriately selected depending on the viscosity and the discharge amount of the optical film constituent material. In the present invention, the shear rate in the extruder 1 is 1 / second to 10,000 / second, preferably 5 / second to 1000 / second, more preferably 10 / second to 100 / second.
　本発明に使用できる押出し機１としては、一般的にプラスチック成形機として入手可能である。 The extruder 1 that can be used in the present invention is generally available as a plastic molding machine.
　押出し機１から押し出された光学フィルム構成材料は、流延ダイ４に送られ、流延ダイ４のスリットから光学フィルム状に押し出される。流延ダイ４はシートや光学フィルムを製造するために用いられるものであれば特に限定はされない。 The optical film constituting material extruded from the extruder 1 is sent to the casting die 4 and extruded from the slit of the casting die 4 into an optical film shape. The casting die 4 is not particularly limited as long as it is used for producing a sheet or an optical film.
　流延ダイ４の材質としては、ハードクロム、炭化クロム、窒化クロム、炭化チタン、炭窒化チタン、窒化チタン、超鋼、セラミック（タングステンカーバイド、酸化アルミ、酸化クロム）等を溶射もしくはメッキし、表面加工としてバフ、＃１０００番手以降の砥石を用いるラッピング、＃１０００番手以上のダイヤモンド砥石を用いる平面切削（切削方向は樹脂の流れ方向に垂直な方向）、電解研磨、電解複合研磨等の加工を施したもの等が挙げられる。流延ダイ４のリップ部の好ましい材質は、流延ダイ４と同様である。またリップ部の表面精度は０．５Ｓ以下が好ましく、０．２Ｓ以下がより好ましい。 The material of the casting die 4 is sprayed or plated with hard chromium, chromium carbide, chromium nitride, titanium carbide, titanium carbonitride, titanium nitride, super steel, ceramic (tungsten carbide, aluminum oxide, chromium oxide), etc. Processing such as buffing, lapping using a # 1000 or higher grinding wheel, plane cutting using a # 1000 or higher diamond grinding wheel (the cutting direction is perpendicular to the resin flow direction), electrolytic polishing, electrolytic composite polishing, etc. And the like. A preferred material for the lip portion of the casting die 4 is the same as that of the casting die 4. The surface accuracy of the lip is preferably 0.5S or less, and more preferably 0.2S or less.
　この流延ダイ４のスリットは、そのギャップが調整可能なように構成されている。 The slit of the casting die 4 is configured so that the gap can be adjusted.
　これを図３（ａ）は流延ダイの要部の一例を示す外観図、図３（ｂ）は流延ダイの要部の一例を示す断面図である。 FIG. 3A is an external view showing an example of the main part of the casting die, and FIG. 3B is a cross-sectional view showing an example of the main part of the casting die.
　流延ダイ４のスリット３２を形成する一対のリップのうち、一方は剛性の低い変形しやすいフレキシブルリップ３３であり、他方は固定リップ３４である。 Among the pair of lips forming the slit 32 of the casting die 4, one is a flexible lip 33 having low rigidity and easily deformed, and the other is a fixed lip 34.
　そして、多数のヒートボルト３５が流延ダイ４の幅方向すなわちスリット３２の長さ方向に一定ピッチで配列されている。各ヒートボルト３５には、埋め込み電気ヒータ３７と冷却媒体通路とを具えたブロック３６が設けられ、各ヒートボルト３５が各ブロック３６を縦に貫通している。 A large number of heat bolts 35 are arranged at a constant pitch in the width direction of the casting die 4, that is, in the length direction of the slit 32. Each heat bolt 35 is provided with a block 36 having an embedded electric heater 37 and a cooling medium passage, and each heat bolt 35 penetrates each block 36 vertically.
　ヒートボルト３５の基部はダイ本体３１に固定され、先端はフレキシブルリップ３３の外面に当接している。そしてブロック３６を常時空冷しながら、埋め込み電気ヒータ３７の入力を増減してブロック３６の温度を上下させ、これによりヒートボルト３５を熱伸縮させて、フレキシブルリップ３３を変位させて光学フィルムの厚さを調整する。 The base of the heat bolt 35 is fixed to the die body 31, and the tip is in contact with the outer surface of the flexible lip 33. While the block 36 is always air-cooled, the input of the embedded electric heater 37 is increased or decreased to raise or lower the temperature of the block 36, thereby causing the heat bolt 35 to thermally expand and contract, thereby displacing the flexible lip 33 to change the thickness of the optical film. Adjust.
　ダイ後流の所要箇所に厚さ計を設け、これによって検出されたウェブ厚さ情報を制御装置にフィードバックし、この厚さ情報を制御装置で設定厚み情報と比較し、同装置から来る補正制御量の信号によってヒートボルトの発熱体の電力またはオン率を制御するようにすることもできる。 Thickness gauges are installed at the required locations in the wake of the die, and the web thickness information detected thereby is fed back to the control device. The thickness information is compared with the set thickness information by the control device, and correction control comes from the same device. It is also possible to control the power or the ON rate of the heat bolt heating element by the amount signal.
　ヒートボルトは、好ましくは、長さ２０～４０ｃｍ、直径７～１４ｍｍを有し、複数、例えば数十本のヒートボルトが、好ましくはピッチ２０～４０ｍｍで配列されている。 The heat bolt preferably has a length of 20 to 40 cm and a diameter of 7 to 14 mm, and a plurality of, for example, several tens of heat bolts are preferably arranged at a pitch of 20 to 40 mm.
　ヒートボルトの代わりに、手動で軸方向に前後動させることによりスリットギャップを調節するボルトを主体とするギャップ調節部材を設けてもよい。 Instead of the heat bolt, a gap adjusting member mainly composed of a bolt for adjusting the slit gap by manually moving back and forth in the axial direction may be provided.
　ギャップ調節部材によって調節されたスリットギャップは、通常２００～１０００μｍ、好ましくは３００～８００μｍ、より好ましくは４００～６００μｍである。 The slit gap adjusted by the gap adjusting member is usually 200 to 1000 μm, preferably 300 to 800 μm, more preferably 400 to 600 μm.
　第１～第３冷却ロールは、肉厚が２０～３０ｍｍ程度のシームレスな鋼管製で、表面が鏡面に仕上げられている。その内部には、冷却液を流す配管が配置されており、配管を流れる冷却液によってロール上の光学フィルムから熱を吸収できるように構成されている。 The first to third cooling rolls are made of seamless steel pipe with a wall thickness of about 20 to 30 mm, and the surface is mirror finished. A pipe for flowing a cooling liquid is arranged inside the pipe, and the cooling liquid flowing through the pipe can absorb heat from the optical film on the roll.
　一方、第１冷却ロール５に当接するタッチロール６は、表面が弾性を有し、第１冷却ロール５への押圧力によって第１冷却ロール５の表面に沿って変形し、第１ロール５との間にニップを形成する。タッチロール６は挟圧回転体ともいう。タッチロール６としては、登録特許３１９４９０４号、登録特許３４２２７９８号、特開２００２－３６３３２号、特開２００２－３６３３３号などで開示されているタッチロールを好ましく用いることができる。これらは市販されているものを用いることもできる。以下にこれらについて、さらに詳細に説明する。 On the other hand, the touch roll 6 in contact with the first cooling roll 5 has an elastic surface and is deformed along the surface of the first cooling roll 5 by the pressing force to the first cooling roll 5. A nip is formed between the two. The touch roll 6 is also called a pinching rotary body. As the touch roll 6, a touch roll disclosed in registered patent 3194904, registered patent 3422798, Japanese Patent Application Laid-Open No. 2002-36332, Japanese Patent Application Laid-Open No. 2002-36333, or the like can be preferably used. These can also use what is marketed. These will be described in more detail below.
　図４は挟圧回転体の一例を示す断面図である。（タッチロール６の第１の例（以下、タッチロールＡ）の概略断面）を示す。図に示すように、タッチロールＡは、可撓性の金属スリーブ４１の内部に弾性ローラ４２を配したものである。 FIG. 4 is a cross-sectional view showing an example of a pinching rotator. (The 1st example of touch roll 6 (henceforth, outline section of touch roll A)) is shown. As shown in the drawing, the touch roll A has an elastic roller 42 disposed inside a flexible metal sleeve 41.
　金属スリーブ４１は厚さ０．３ｍｍのステンレス製であり、可撓性を有する。金属スリーブ４１が薄すぎると強度が不足し、逆に厚すぎると弾性が不足する。 The metal sleeve 41 is made of stainless steel having a thickness of 0.3 mm and has flexibility. If the metal sleeve 41 is too thin, the strength is insufficient, whereas if it is too thick, the elasticity is insufficient.
　これらのことから、金属スリーブ４１の厚さとしては、０．１～１．５ｍｍが好ましい。 For these reasons, the thickness of the metal sleeve 41 is preferably 0.1 to 1.5 mm.
　弾性ローラ４２は、軸受を介して回転自在な金属製の内筒４３の表面にゴム４４を設けてロール状としたものである。 The elastic roller 42 is formed in a roll shape by providing a rubber 44 on the surface of a metal inner cylinder 43 that is rotatable through a bearing.
　そして、タッチロールＡが第１冷却ロール５に向けて押圧されると、弾性ローラ４２が金属スリーブ４１を第１冷却ロール５に押しつけ、金属スリープ４１及び弾性ローラ４２は第１冷却ロール５の形状になじんだ形状に対応しつつ変形し、第１冷却ロールとの間にニップを形成する。金属スリーブ４１の内部で弾性ローラ４２との間に形成される空間には、冷却水４５が流される。 When the touch roll A is pressed toward the first cooling roll 5, the elastic roller 42 presses the metal sleeve 41 against the first cooling roll 5, and the metal sleep 41 and the elastic roller 42 have the shape of the first cooling roll 5. It deforms corresponding to the familiar shape, and forms a nip with the first cooling roll. Cooling water 45 flows in a space formed between the metal sleeve 41 and the elastic roller 42.
　図５は挟圧回転体の第２の例（以下、タッチロールＢ）を示す回転軸に垂直な平面での断面図である。 FIG. 5 is a cross-sectional view taken along a plane perpendicular to the rotation axis, showing a second example (hereinafter referred to as touch roll B) of the pinching rotator.
　図６は挟圧回転体の第２の例（タッチロールＢ）の回転軸を含む平面の一例を示す断面図である。 FIG. 6 is a cross-sectional view showing an example of a plane including the rotation axis of the second example (touch roll B) of the pinching rotator.
　図５、図６においてタッチロールＢは、可撓性を有する、シームレスなステンレス鋼管製（厚さ４ｍｍ）の外筒５１と、この外筒５１の内側に同一軸心状に配置された高剛性の金属内筒５２とから概略構成されている。 5 and 6, the touch roll B is a flexible and seamless outer tube 51 made of a stainless steel pipe (thickness 4 mm), and a high rigidity arranged in the same axial center inside the outer tube 51. The metal inner cylinder 52 is generally configured.
　外筒５１と内筒５２との間の空間５３には、冷却液５４が流される。詳しくは、タッチロールＢは、両端の回転軸５５ａ、５５ｂに外筒支持フランジ５６ａ、５６ｂが取付けられ、これら両外筒支持フランジ５６ａ、５６ｂの外周部間に薄肉金属外筒５１が取付けられている。 A coolant 54 is caused to flow in a space 53 between the outer cylinder 51 and the inner cylinder 52. Specifically, in the touch roll B, outer cylinder support flanges 56a and 56b are attached to the rotation shafts 55a and 55b at both ends, and a thin metal outer cylinder 51 is attached between the outer peripheral portions of the both outer cylinder support flanges 56a and 56b. Yes.
　また、一方の回転軸５５ａの軸心部に形成されて流体戻り通路５７を形成する流体排出孔５８内に、流体供給管５９が同一軸心状に配設され、この流体供給管５９が薄肉金属外筒５１内の軸心部に配置された流体軸筒６０に接続固定されている。 A fluid supply pipe 59 is disposed in the same axial center in a fluid discharge hole 58 formed in the axial center portion of one rotary shaft 55a and forming a fluid return passage 57. The fluid supply pipe 59 is thin-walled. It is connected and fixed to a fluid shaft cylinder 60 arranged at the axial center in the metal outer cylinder 51.
　この流体軸筒６０の両端部に内筒支持フランジ６１ａ、６１ｂがそれぞれ取り付けられ、これら内筒支持フランジ６１ａ、６１ｂの外周部間から他端側外筒支持フランジ５６ｂにわたって約１５～２０ｍｍ程度の肉厚を有する金属内筒５２が取付けられている。 Inner cylinder support flanges 61a and 61b are attached to both ends of the fluid shaft cylinder 60, respectively, and a thickness of about 15 to 20 mm between the outer periphery of the inner cylinder support flanges 61a and 61b and the other end side outer cylinder support flange 56b. A metal inner cylinder 52 having a thickness is attached.
　そしてこの金属内筒５２と薄肉金属外筒５１との間に、例えば１０ｍｍ程度の冷却液の流送空間５３が形成され、また金属内筒５２に両端部近傍には、流送空間５３と内筒支持フランジ６１ａ、６１ｂ外側の中間通路６２ａ、６２ｂとを連通する流出口５２ａ及び流入口５２ｂがそれぞれ形成されている。 A cooling liquid flow space 53 of, for example, about 10 mm is formed between the metal inner cylinder 52 and the thin metal outer cylinder 51, and the metal inner cylinder 52 has a flow space 53 and an inner space near both ends. An outlet 52a and an inlet 52b are formed to communicate with the intermediate passages 62a and 62b outside the cylinder support flanges 61a and 61b, respectively.
　また、外筒５１は、ゴム弾性に近い柔軟性と可撓性、復元性をもたせるために、弾性力学の薄肉円筒理論が適用できる範囲内で薄肉化が図られている。 In addition, the outer cylinder 51 is thinned within a range in which the thin cylinder theory of elastic mechanics can be applied in order to have flexibility, flexibility and resilience close to rubber elasticity.
　この薄肉円筒理論で評価される可撓性は、肉厚ｔ／ロール半径ｒで表されており、ｔ／ｒが小さいほど可撓性が高まる。 The flexibility evaluated by the thin-walled cylinder theory is represented by the thickness t / roll radius r, and the flexibility increases as t / r decreases.
　このタッチロールＢではｔ／ｒ≦０．０３の場合に可撓性が最適の条件となる。 In this touch roll B, the flexibility is the optimum condition when t / r ≦ 0.03.
　通常、一般的に使用されているタッチロールは、ロール径Ｒ＝２００～５００ｍｍ（ロール半径ｒ＝Ｒ／２）、ロール有効幅Ｌ＝５００～１６００ｍｍで、ｒ／Ｌ＜１で横長の形状である。 In general, a touch roll generally used has a roll diameter R = 200 to 500 mm (roll radius r = R / 2), a roll effective width L = 500 to 1600 mm, and a horizontally long shape with r / L <1. is there.
　そして図６に示すように、例えばロール径Ｒ＝３００ｍｍ、ロール有効幅Ｌ＝１２００ｍｍの場合、肉厚ｔの適正範囲は１５０×０．０３＝４．５ｍｍ以下であるが、溶融シート幅を１３００ｍｍに対して平均線圧を９８Ｎ／ｃｍで挟圧する場合、同一形状のゴムロールと比較して、外筒５１の肉厚を３ｍｍとすることで相当ばね定数も等しく、外筒５１と冷却ロールとのニップのロール回転方向のニップ幅ｋも約９ｍｍで、このゴムロールのニップ幅約１２ｍｍとほぼ近い値を示し、同じような条件下で挟圧できることが分かる。 As shown in FIG. 6, for example, when the roll diameter R = 300 mm and the roll effective width L = 1200 mm, the appropriate range of the wall thickness t is 150 × 0.03 = 4.5 mm or less, but the molten sheet width is 1300 mm. On the other hand, when the average linear pressure is clamped at 98 N / cm, the equivalent spring constant is equal by setting the wall thickness of the outer cylinder 51 to 3 mm compared to the rubber roll of the same shape. The nip width k in the roll rotation direction of the nip is also about 9 mm, which is almost the same as the nip width of this rubber roll of about 12 mm.
　なお、このニップ幅ｋにおけるたわみ量は０．０５～０．１ｍｍ程度である。 The deflection amount at the nip width k is about 0.05 to 0.1 mm.
　ここで、ｔ／ｒ≦０．０３としたが、一般的なロール径Ｒ＝２００～５００ｍｍの場合では、特に２ｍｍ≦ｔ≦５ｍｍの範囲とすると、可撓性も十分に得られ、また機械加工による薄肉化も容易に実施でき、極めて実用的な範囲となる。肉厚が２ｍｍ以下では加工時の弾性変形で高精度な加工ができない。 Here, t / r ≦ 0.03, but in the case of a general roll diameter R = 200 to 500 mm, sufficient flexibility can be obtained especially in the range of 2 mm ≦ t ≦ 5 mm. Thinning by processing can be easily performed, and is in a very practical range. If the wall thickness is 2 mm or less, high-precision processing cannot be performed due to elastic deformation during processing.
　この２ｍｍ≦ｔ≦５ｍｍの換算値は、一般的なロール径に対して０．００８≦ｔ／ｒ≦０．０５となるが、実用にあたってはｔ／ｒ≦０．０３の条件下でロール径に比例して肉厚も大きくするとよい。 The converted value of 2 mm ≦ t ≦ 5 mm is 0.008 ≦ t / r ≦ 0.05 with respect to a general roll diameter, but in practical use, the roll diameter under the condition of t / r ≦ 0.03. The wall thickness should be increased in proportion to
　例えばロール径：Ｒ＝２００ではｔ＝２～３ｍｍ、ロール径：Ｒ＝５００ではｔ＝４～５ｍｍの範囲で選択する。 For example, when roll diameter: R = 200, t = 2 to 3 mm, and when roll diameter: R = 500, t = 4 to 5 mm.
　このタッチロールＡ、Ｂは付勢手段により第１冷却ロールに向けて付勢される。その付勢手段の付勢力をＦ、ニップにおける光学フィルムの、第１冷却ロール５の回転軸に沿った方向の幅Ｗを除した値Ｆ／Ｗ（線圧）は、９．８～１４７Ｎ／ｃｍに設定される。 The touch rolls A and B are urged toward the first cooling roll by the urging means. The value F / W (linear pressure) obtained by dividing the urging force of the urging means by F and dividing the width W of the optical film in the nip along the rotation axis of the first cooling roll 5 is 9.8 to 147 N / Set to cm.
　本発明において、タッチロールＡ、Ｂと第１冷却ロール５との間にニップが形成され、当該ニップを光学フィルムが通過する間に平面性を矯正することが好ましい。従って、タッチロールが剛体で構成され、第１冷却ロールとの間にニップが形成されない場合と比べて、小さい線圧で長時間かけて光学フィルムを挟圧するので、平面性をより確実に矯正することができる。 In the present invention, it is preferable that a nip is formed between the touch rolls A and B and the first cooling roll 5, and the flatness is corrected while the optical film passes through the nip. Accordingly, the optical film is sandwiched over a long time with a small linear pressure, compared to the case where the touch roll is formed of a rigid body and no nip is formed between the first cooling roll and the flatness is more reliably corrected. be able to.
　すなわち、線圧が９．８Ｎ／ｃｍよりも小さいと、ダイラインを十分に解消することができなくなる。逆に、線圧が１４７Ｎ／ｃｍよりも大きいと、光学フィルムがニップを通過しにくくなり、光学フィルムの厚さにかえってムラができてしまう。 That is, when the linear pressure is smaller than 9.8 N / cm, the die line cannot be sufficiently eliminated. On the other hand, if the linear pressure is greater than 147 N / cm, the optical film is difficult to pass through the nip, resulting in unevenness in place of the thickness of the optical film.
　また、タッチロールＡ、Ｂの表面を金属で構成することにより、タッチロールの表面がゴムである場合よりもタッチロールＡ、Ｂの表面を平滑にすることができるので、平滑性の高い光学フィルムを得ることができる。なお、弾性ローラ４２の弾性体４４の材質としては、エチレンプロピレンゴム、ネオプレンゴム、シリコンゴム等を用いることができる。 In addition, since the surfaces of the touch rolls A and B are made of metal, the surfaces of the touch rolls A and B can be made smoother than when the surface of the touch roll is rubber. Can be obtained. In addition, as a material of the elastic body 44 of the elastic roller 42, ethylene propylene rubber, neoprene rubber, silicon rubber, or the like can be used.
　さて、タッチロール６によってダイラインを良好に解消するためには、タッチロール６が光学フィルムを挟圧するときの光学フィルムの粘度が適切な範囲であることが重要となる。 Now, in order to satisfactorily eliminate the die line by the touch roll 6, it is important that the viscosity of the optical film when the touch roll 6 sandwiches the optical film is in an appropriate range.
　また、セルロースエステルは温度による粘度の変化が比較的大きいことが知られている。 In addition, it is known that cellulose ester has a relatively large change in viscosity with temperature.
　従って、タッチロール６が光学フィルムを挟圧するときの粘度を適切な範囲に設定するためには、タッチロール６がセルロースフィルムを挟圧するときの光学フィルムの温度を適切な範囲に設定することが重要となる。 Therefore, in order to set the viscosity when the touch roll 6 clamps the optical film to an appropriate range, it is important to set the temperature of the optical film when the touch roll 6 clamps the cellulose film to an appropriate range. It becomes.
　光学フィルムのガラス転移温度をＴｇとしたとき、光学フィルムがタッチロール６に挟圧される直前の光学フィルムの温度Ｔを、Ｔｇ＜Ｔ＜Ｔｇ＋１１０℃を満たすように設定することが好ましい。 When the glass transition temperature of the optical film is Tg, it is preferable to set the temperature T of the optical film immediately before the optical film is sandwiched between the touch rolls 6 so as to satisfy Tg <T <Tg + 110 ° C.
　即ち、タッチロール６に挟圧される直前の光学フィルムの温度Ｔが上記の範囲にすると、光学フィルムを挟圧するときの光学フィルムの粘度を適切な範囲に設定することができ、ダイラインの矯正が可能となり、また、光学フィルム表面とロールが均一に接着し、ダイラインの矯正が可能となる。 That is, when the temperature T of the optical film immediately before being sandwiched between the touch rolls 6 is within the above range, the viscosity of the optical film when sandwiching the optical film can be set to an appropriate range, and the die line can be corrected. Further, the surface of the optical film and the roll are uniformly bonded, and the die line can be corrected.
　好ましくはＴｇ＋１０℃＜Ｔ＜Ｔｇ＋９０℃、更に好ましくはＴｇ＋２０℃＜Ｔ＜Ｔｇ＋７０℃である。 Preferably, Tg + 10 ° C. <T <Tg + 90 ° C., more preferably Tg + 20 ° C. <T <Tg + 70 ° C.
　タッチロール６が光学フィルムを挟圧するときの光学フィルムの温度を適切な範囲に設定するには、流延ダイ４から押し出された溶融物が第１冷却ロール５に接触する位置から第１冷却ロール５とタッチロール６とのニップの、第１冷却ロール５の回転方向に沿った長さＬを調整すればよい。 In order to set the temperature of the optical film when the touch roll 6 clamps the optical film to an appropriate range, the first cooling roll is moved from the position where the melt extruded from the casting die 4 contacts the first cooling roll 5. What is necessary is just to adjust the length L along the rotation direction of the 1st cooling roll 5 of the nip of 5 and the touch roll 6. FIG.
　本発明において、第１冷却ロール５、第２冷却ロール７に好ましい材質は、炭素鋼、ステンレス鋼、樹脂、等が挙げられる。また、表面精度は高くすることが好ましく表面粗さとして０．３Ｓ以下、より好ましくは０．０１Ｓ以下とする。 In the present invention, preferable materials for the first cooling roll 5 and the second cooling roll 7 include carbon steel, stainless steel, resin, and the like. The surface accuracy is preferably increased, and the surface roughness is set to 0.3 S or less, more preferably 0.01 S or less.
　本発明においては、流延ダイ４の開口部（リップ）から第１冷却ロール５までの部分を７０ｋＰａ以下に減圧させることにより、上記、ダイラインの矯正効果がより大きく発現する。 In the present invention, by reducing the pressure from the opening (lip) of the casting die 4 to the first cooling roll 5 to 70 kPa or less, the above-described die line correction effect is more greatly manifested.
　好ましくは減圧は５０～７０ｋＰａである。流延ダイ４の開口部（リップ）から第１冷却ロール５までの部分の圧力を７０ｋＰａ以下に保つ方法としては、特に制限はないが、流延ダイ４からロール周辺を耐圧部材で覆い、減圧する等の方法がある。 Preferably, the reduced pressure is 50 to 70 kPa. There is no particular limitation on the method of keeping the pressure in the portion from the opening (lip) of the casting die 4 to the first cooling roll 5 at 70 kPa or less, but the pressure around the roll from the casting die 4 is covered with a pressure-resistant member, and the pressure is reduced. There are ways to do it.
　このとき、吸引装置は、装置自体が昇華物の付着場所にならないようヒータで加熱する等の処置を施すことが好ましい。本発明では、吸引圧が小さすぎると昇華物を効果的に吸引できないため、適当な吸引圧とする必要がある。 At this time, the suction device is preferably subjected to a treatment such as heating with a heater so that the device itself does not become a place where the sublimate adheres. In the present invention, if the suction pressure is too small, the sublimate cannot be sucked effectively, so it is necessary to set the suction pressure to an appropriate value.
　本発明において、Ｔダイ４から溶融状態のフィルム状のセルロースエステルを、第１冷却ロール５、第２冷却ロール７、及び第３冷却ロール８に順次密着させて搬送しながら冷却固化させ、未延伸の光学フィルム１０を得る。 In the present invention, the melted film-like cellulose ester from the T die 4 is brought into close contact with the first cooling roll 5, the second cooling roll 7, and the third cooling roll 8 in order to be cooled and solidified, and unstretched. The optical film 10 is obtained.
　図１に示す本発明の実施形態の一例では、第３冷却ロール８から剥離ロール９によって剥離した冷却固化された未延伸の光学フィルム１０は、ダンサーロール（光学フィルム張力調整ロール）１１を経て延伸装置１２に導き、そこで光学フィルム１０を幅方向に延伸する。この延伸により、光学フィルム中の分子が配向される。 In the example of the embodiment of the present invention shown in FIG. 1, the cooled and solidified unstretched optical film 10 peeled from the third cooling roll 8 by the peeling roll 9 is stretched through a dancer roll (optical film tension adjusting roll) 11. It leads to the apparatus 12, and the optical film 10 is extended | stretched in the width direction there. By this stretching, the molecules in the optical film are oriented.
　光学フィルムを幅方向に延伸する方法は、公知のテンター等を好ましく用いることができる。特に延伸方向を幅方向とすることで、偏光フィルムとの積層がロール形態で実施できるので好ましい。 As a method of stretching the optical film in the width direction, a known tenter or the like can be preferably used. In particular, it is preferable to set the stretching direction to the width direction because lamination with a polarizing film can be performed in a roll form.
　フィルムを幅方向に延伸することで、光学フィルムの遅相軸は幅方向になる。一方、偏光フィルムの透過軸も、通常、幅方向である。偏光フィルムの透過軸と光学フィルムの遅相軸とが平行になるように積層した偏光板を液晶表示装置に組み込むことで、液晶表示装置の表示コントラストを高くすることができるとともに、良好な視野角が得られる。 By stretching the film in the width direction, the slow axis of the optical film becomes the width direction. On the other hand, the transmission axis of the polarizing film is also usually in the width direction. By incorporating a polarizing plate in which the transmission axis of the polarizing film and the slow axis of the optical film are parallel to each other into the liquid crystal display device, the display contrast of the liquid crystal display device can be increased and a good viewing angle can be obtained. Is obtained.
　光学フィルムのガラス転移温度Ｔｇは光学フィルムを構成する材料種及び構成する材料の比率を異ならしめることにより制御できる。光学フィルムとして位相差フィルムを作製する場合、Ｔｇは１２０℃以上、好ましくは１３５℃以上とすることが好ましい。液晶表示装置においては、画像の表示状態において、装置自身の温度上昇、例えば光源由来の温度上昇によってフィルムの温度環境が変化する。 The glass transition temperature Tg of the optical film can be controlled by varying the material type constituting the optical film and the ratio of the constituting material. When a retardation film is produced as an optical film, Tg is preferably 120 ° C. or higher, preferably 135 ° C. or higher. In the liquid crystal display device, in the image display state, the temperature environment of the film changes due to the temperature rise of the device itself, for example, the temperature rise derived from the light source.
　このときフィルムの使用環境温度よりも光学フィルムのＴｇが低いと、延伸によってフィルム内部に固定された分子の配向状態に由来するリターデーション値及びフィルムとしての寸法形状に大きな変化を与えることとなる。 At this time, if the Tg of the optical film is lower than the use environment temperature of the film, the retardation value derived from the orientation state of the molecules fixed inside the film by stretching and the dimensional shape as the film are greatly changed.
　光学フィルムのＴｇが高過ぎると、光学フィルムをフィルム化するとき温度が高くなるために加熱するエネルギー消費が高くなり、また光学フィルム化するときの材料自身の分解、それによる着色が生じることがあり、従って、Ｔｇは２５０℃以下が好ましい。 If the Tg of the optical film is too high, the temperature when the optical film is formed becomes high, so that the energy consumption for heating becomes high, and the material itself may be decomposed and colored due to the optical film. Therefore, Tg is preferably 250 ° C. or less.
　また延伸工程には公知の熱固定条件、冷却、緩和処理を行ってもよく、目的とする光学フィルムに要求される特性を有するように適宜調整すればよい。 In the stretching step, known heat setting conditions, cooling, and relaxation treatment may be performed, and it may be appropriately adjusted so as to have characteristics required for the target optical film.
　位相差フィルムの物性と液晶表示装置の視野角拡大のための位相差フィルムとしての機能付与するために、上記延伸工程、熱固定処理は適宜選択して行われている。 In order to provide the physical properties of the retardation film and the function as a retardation film for expanding the viewing angle of the liquid crystal display device, the stretching step and the heat setting treatment are appropriately selected and performed.
　このような延伸工程、熱固定処理を含む場合、加熱加圧工程は、それらの延伸工程、熱固定処理の前に行うようにする。 When such a stretching step and heat setting treatment are included, the heating and pressurizing step is performed before the stretching step and heat setting treatment.
　光学フィルムとして位相差フィルムを製造し、更に偏光板保護フィルムの機能を複合させる場合、屈折率制御を行う必要が生じるが、その屈折率制御は延伸操作により行うことが可能であり、また延伸操作が好ましい方法である。以下、その延伸方法について説明する。 When producing a retardation film as an optical film and further combining the functions of a polarizing plate protective film, it is necessary to control the refractive index. However, the refractive index can be controlled by a stretching operation. Is a preferred method. Hereinafter, the stretching method will be described.
　位相差フィルムの延伸工程において、セルロース樹脂の１方向に１．０～２．０倍及びフィルム面内にそれと直交する方向に１．０１～２．５倍延伸することで、必要とされるリターデーションＲｏ及びＲｔを制御することができる。ここで、Ｒｏとは面内リターデーションを示し、Ｒｔとは厚み方向リターデーションを示す。 In the retardation film stretching step, the required litter is stretched by 1.0 to 2.0 times in one direction of the cellulose resin and 1.01 to 2.5 times in the direction perpendicular to the film plane. The foundation Ro and Rt can be controlled. Here, Ro indicates in-plane retardation, and Rt indicates thickness direction retardation.
　リターデーションＲｏ、Ｒｔは下記式により求められる。 Retardation Ro and Rt are calculated | required by a following formula.
　式（ｉ）　Ｒｏ＝（ｎｘ－ｎｙ）×ｄ
　式（ii）　Ｒｔ＝（（ｎｘ＋ｎｙ）／２－ｎｚ）×ｄ
　（式中、ｎｘはフィルム面内の遅相軸方向の屈折率、ｎｙはフィルム面内の進相軸方向の屈折率、ｎｚはフィルムの厚み方向の屈折率（屈折率は２３℃、５５％ＲＨの環境下、波長５９０ｎｍで測定）、ｄはフィルムの厚さ（ｎｍ）を表す。）
　光学フィルムの屈折率は、アッベ屈折率計（４Ｔ）を用いて、フィルムの厚さは市販のマイクロメーターを用いて、リターデーション値は、自動複屈折計ＫＯＢＲＡ－２１ＡＤＨ（王子計測機器（株）製）等を用いて、各々測定することが出来る。 Formula (i) Ro = (nx−ny) × d
Formula (ii) Rt = ((nx + ny) / 2−nz) × d
(Where nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the fast axis direction in the film plane, nz is the refractive index in the thickness direction of the film (refractive index is 23 ° C., 55%) (Measured at a wavelength of 590 nm in an RH environment), d represents the thickness (nm) of the film.)
The refractive index of the optical film is an Abbe refractometer (4T), the thickness of the film is a commercially available micrometer, and the retardation value is an automatic birefringence meter KOBRA-21ADH (Oji Scientific Instruments) Etc.) can be used for each measurement.
　延伸は、例えば光学フィルムの流延方向（ＭＤ方向ともいう）及びそれと光学フィルム面内で直交する方向、即ち幅方向（ＴＤ方向ともいう）に対して、逐次または同時に行うことができる。このとき少なくとも１方向に対しての延伸倍率が小さ過ぎると十分な位相差が得られず、大き過ぎると延伸が困難となり光学フィルム破断が発生してしまう場合がある。 Stretching can be performed sequentially or simultaneously, for example, in the casting direction (also referred to as MD direction) of the optical film and in the direction orthogonal to the optical film plane, that is, in the width direction (also referred to as TD direction). At this time, if the stretching ratio in at least one direction is too small, a sufficient phase difference cannot be obtained, and if it is too large, stretching becomes difficult and optical film breakage may occur.
　例えば流延方向に延伸した場合、幅方向の収縮が大き過ぎると、ｎｚの値が大きくなり過ぎてしまう。この場合、光学フィルムの幅収縮を抑制、或いは幅方向にも延伸することで改善できる。 For example, when stretching in the casting direction, if the shrinkage in the width direction is too large, the value of nz becomes too large. In this case, the width shrinkage of the optical film can be suppressed or improved by stretching in the width direction.
　幅方向に延伸する場合、幅方向で屈折率に分布が生じることがある。この分布は、テンター法を用いた場合に現れることがあり、光学フィルムを幅方向に延伸したことで、光学フィルム中央部に収縮力が発生し、端部は固定されていることにより生じる現象で、いわゆるボーイング現象と呼ばれるものと考えられる。この場合でも、流延方向に延伸することで、ボーイング現象を抑制でき、幅方向の位相差の分布を少なくできるため、流延方向、幅方向の２軸方向に延伸することが好ましい。 When stretching in the width direction, the refractive index may be distributed in the width direction. This distribution may appear when the tenter method is used. By stretching the optical film in the width direction, a contraction force is generated at the center of the optical film, and the phenomenon is caused by the end being fixed. The so-called Boeing phenomenon is considered. Even in this case, by stretching in the casting direction, the bowing phenomenon can be suppressed and the distribution of the phase difference in the width direction can be reduced. Therefore, stretching in the biaxial direction of the casting direction and the width direction is preferable.
　また、互いに直行する２軸方向に延伸することにより、得られる光学フィルムの膜厚変動が減少できる。位相差フィルムの膜厚変動が大き過ぎると位相差のムラとなり、液晶表示装置に用いたとき着色等のムラが問題となることがある。 Moreover, the film thickness fluctuation | variation of the optical film obtained can be reduced by extending | stretching in the biaxial direction orthogonal to each other. When the film thickness variation of the retardation film is too large, unevenness of the retardation is caused, and unevenness such as coloring may be a problem when used in a liquid crystal display device.
　光学フィルムの膜厚変動は、±３％、更に±１％の範囲とすることが好ましい。 The film thickness variation of the optical film is preferably in the range of ± 3%, more preferably ± 1%.
　以上のような目的において、互いに直交する２軸方向に延伸する方法は有効であり、互いに直交する２軸方向の延伸倍率は、それぞれ最終的には流延方向に１．０～２．０倍、幅方向に１．０１～２．５倍の範囲とすることが好ましく、流延方向に１．０１～２．０倍、幅方向に１．０５～２．０倍の範囲で行うことが必要とされるリターデーション値を得るためにより好ましい。 For the purposes as described above, a method of stretching in the biaxial directions perpendicular to each other is effective, and the stretching ratio in the biaxial directions perpendicular to each other is finally 1.0 to 2.0 times in the casting direction. The width is preferably in the range of 1.01 to 2.5 times, in the range of 1.01 to 2.0 times in the casting direction and 1.05 to 2.0 times in the width direction. It is more preferred to obtain the required retardation value.
　流延方向に偏光子の吸収軸が存在する場合、幅方向に偏光子の透過軸が一致することになる。長尺状の偏光板を得るためには、位相差フィルムは、幅方向に遅相軸を得るように延伸することが好ましい。 When the absorption axis of the polarizer exists in the casting direction, the transmission axis of the polarizer matches with the width direction. In order to obtain a long polarizing plate, the retardation film is preferably stretched so as to obtain a slow axis in the width direction.
　応力に対して、正の複屈折を得るセルロースエステルを用いる場合、上述の構成から幅方向に延伸することで、位相差フィルムの遅相軸を幅方向に付与することができる。この場合、表示品質の向上のためには、位相差フィルムの遅相軸が幅方向にあるほうが好ましく、目的とするリターデーション値を得るためには、
　式、（幅方向の延伸倍率）＞（流延方向の延伸倍率）
の条件を満たすことが必要である。 When cellulose ester that obtains positive birefringence with respect to stress is used, the slow axis of the retardation film can be imparted in the width direction by stretching in the width direction from the above configuration. In this case, in order to improve display quality, the slow axis of the retardation film is preferably in the width direction, and in order to obtain the desired retardation value,
Formula (stretch ratio in the width direction)> (stretch ratio in the casting direction)
It is necessary to satisfy the following conditions.
　位相差フィルムの場合、フィルムの遅相軸または進相軸がフィルム面内に存在し、流延方向とのなす角度をθ１とすると、θ１は－１～＋１°、好ましくは－０．５～＋０．５°となるようにすることが好ましい。 In the case of a retardation film, if the slow axis or the fast axis of the film exists in the film plane and the angle formed with the casting direction is θ1, θ1 is −1 to + 1 °, preferably −0.5 to It is preferable that the angle is + 0.5 °.
　このθ１は配向角として定義でき、θ１の測定は、自動複屈折計ＫＯＢＲＡ－２１ＡＤＨ（王子計測機器社製）を用いて行うことができる。 This θ1 can be defined as an orientation angle, and θ1 can be measured using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments).
　θ１が各々上記関係を満たすことは、表示画像において高い輝度を得ること、光漏れを抑制または防止することに寄与し、カラー液晶表示装置においては忠実な色再現に寄与する。 When each θ1 satisfies the above relationship, it contributes to obtaining high luminance in a display image, suppressing or preventing light leakage, and contributing to faithful color reproduction in a color liquid crystal display device.
　位相差フィルムがマルチドメイン化されたＶＡモードに用いられるとき、位相差フィルムの配置は、位相差フィルムの進相軸がθ１として上記領域に配置することで、表示画質の向上に寄与し、偏光板及び液晶表示装置としてＭＶＡモードとしたとき、例えば図７に示す構成をとることができる。 When the retardation film is used for the multi-domain VA mode, the retardation film is arranged in the above region with the fast axis of the retardation film being θ1, which contributes to the improvement of display image quality. When the plate and the liquid crystal display device are in the MVA mode, for example, the configuration shown in FIG. 7 can be adopted.
　図７において、２１ａ、２１ｂは保護フィルム、２２ａ、２２ｂは位相差フィルム、２５ａ、２５ｂは偏光子、２３ａ、２３ｂはフィルムの遅相軸方向、２４ａ、２４ｂは偏光子の透過軸方向、２６ａ、２６ｂは偏光板、２７は液晶セル、２９は液晶表示装置を示している。 In FIG. 7, 21a and 21b are protective films, 22a and 22b are retardation films, 25a and 25b are polarizers, 23a and 23b are slow axis directions of the film, 24a and 24b are transmission axis directions of the polarizer, 26a, Reference numeral 26b denotes a polarizing plate, 27 denotes a liquid crystal cell, and 29 denotes a liquid crystal display device.
　光学フィルムの面内方向のリターデーションＲｏ分布は、５％以下に調整することが好ましく、より好ましくは２％以下であり、特に好ましくは、１．５％以下である。また、フィルムの厚み方向のリターデーションＲｔ分布を１０％以下に調整することが好ましいが、更に好ましくは、２％以下であり、特に好ましくは、１．５％以下である。 The retardation Ro distribution in the in-plane direction of the optical film is preferably adjusted to 5% or less, more preferably 2% or less, and particularly preferably 1.5% or less. The retardation Rt distribution in the thickness direction of the film is preferably adjusted to 10% or less, more preferably 2% or less, and particularly preferably 1.5% or less.
　位相差フィルムにおいて、リターデーション値の分布変動はより小さい方が好ましく、液晶表示装置に位相差フィルムを含む偏光板を用いるとき、該リターデーション分布変動が小さいことが色ムラ等を防止する観点で好ましい。 In the retardation film, the retardation value distribution fluctuation is preferably smaller, and when a polarizing plate including a retardation film is used in a liquid crystal display device, the retardation distribution fluctuation is small from the viewpoint of preventing color unevenness and the like. preferable.
　位相差フィルムを、ＶＡモードまたはＴＮモードの液晶セルの表示品質の向上に適したリターデーション値を有するように調整し、特にＶＡモードとして上記のマルチドメインに分割してＭＶＡモードに好ましく用いられるようにするには、面内リターデーションＲｏを３０ｎｍよりも大きく、９５ｎｍ以下に、かつ厚み方向リターデーションＲｔを７０ｎｍよりも大きく、４００ｎｍ以下の値に調整することが求められる。 The retardation film is adjusted to have a retardation value suitable for improving the display quality of the VA mode or TN mode liquid crystal cell, and is preferably used for the MVA mode by dividing the retardation film into the above multi-domain as the VA mode. To achieve this, it is required to adjust the in-plane retardation Ro to a value greater than 30 nm and 95 nm or less, and a thickness direction retardation Rt greater than 70 nm and 400 nm or less.
　上記の面内リターデーションＲｏは、２枚の偏光板がクロスニコルに配置され、偏光板の間に液晶セルが配置された、例えば図７に示す構成であるときに、表示面の法線方向から観察するときを基準にしてクロスニコル状態にあるとき、表示面の法線から斜めに観察したとき、偏光板のクロスニコル状態からのずれが生じ、これが要因となる光漏れを主に補償する。 The in-plane retardation Ro is observed from the normal direction of the display surface when the two polarizing plates are arranged in crossed Nicols and the liquid crystal cell is arranged between the polarizing plates, for example, in the configuration shown in FIG. When the display is in the crossed Nicol state with reference to the time when it is observed, the polarizing plate is displaced from the crossed Nicol state when observed obliquely from the normal line of the display surface, and light leakage caused by this is mainly compensated.
　厚さ方向のリターデーションは、上記ＴＮモードやＶＡモード、特にＭＶＡモードにおいて液晶セルが黒表示状態であるときに、同様に斜めから見たときに認められる液晶セルの複屈折を主に補償するために寄与する。 The retardation in the thickness direction mainly compensates for the birefringence of the liquid crystal cell similarly observed when viewed from an oblique direction when the liquid crystal cell is in a black display state in the TN mode or VA mode, particularly in the MVA mode. To contribute.
　図７に示すように、液晶表示装置において、液晶セルの上下に偏光板が二枚配置された構成である場合、図中の２２ａ及び２２ｂは、厚み方向リターデーションＲｔの配分を選択することができ、上記範囲を満たしかつ厚み方向リターデーションＲｔの両者の合計値が１４０ｎｍよりも大きくかつ５００ｎｍ以下にすることが好ましい。 As shown in FIG. 7, in the liquid crystal display device, when two polarizing plates are arranged above and below the liquid crystal cell, 22a and 22b in the figure can select the distribution of the thickness direction retardation Rt. Preferably, the total value of both of the above-mentioned ranges and the thickness direction retardation Rt is larger than 140 nm and 500 nm or less.
　このとき２２ａ及び２２ｂの面内リターデーションＲｏ、厚み方向リターデーションＲｔが両者同じであることが、工業的な偏光板の生産性向上において好ましい。 At this time, it is preferable for improving the productivity of the industrial polarizing plate that the in-plane retardation Ro and the thickness direction retardation Rt of 22a and 22b are the same.
　特に好ましくは面内リターデーションＲｏが４５ｎｍよりも大きくかつ５５ｎｍ以下であり、かつ厚み方向リターデーションＲｔが１１５ｎｍよりも大きく１２５ｎｍ以下で、図７の構成でＭＶＡモードの液晶セルに適用することである。 Particularly preferably, the in-plane retardation Ro is greater than 45 nm and not greater than 55 nm, and the thickness direction retardation Rt is greater than 115 nm and not greater than 125 nm, and is applied to the MVA mode liquid crystal cell with the configuration of FIG. .
　液晶表示装置において、一方の偏光板に例えば市販の偏光板保護フィルムとして面内リターデーションＲｏ＝０～４ｎｍ及び厚み方向リターデーションＲｔ＝２０～６０ｎｍで厚さ３５～８５μｍのＴＡＣフィルムが、例えば図７の２２ｂの位置で使用されている場合、他方の偏光板に配置される偏光フィルム、例えば、図７の２２ａに配置する位相差フィルムは、面内リターデーションＲｏが３０ｎｍよりも大きく９５ｎｍ以下であり、かつ厚み方向リターデーションＲｔが１４０ｎｍよりも大きく４００ｎｍ以下であるものを使用するようにすると、表示品質が向上し、かつフィルムの生産面からも好ましい。 In a liquid crystal display device, for example, a TAC film having an in-plane retardation Ro = 0 to 4 nm and a thickness direction retardation Rt = 20 to 60 nm and a thickness of 35 to 85 μm is used as one polarizing plate as a commercially available polarizing plate protective film. 7 is used at the position 22b, the polarizing film disposed on the other polarizing plate, for example, the retardation film disposed on 22a in FIG. 7, has an in-plane retardation Ro of more than 30 nm and not more than 95 nm. In addition, use of a film having a thickness direction retardation Rt of greater than 140 nm and not greater than 400 nm is preferable from the viewpoint of improving the display quality and producing the film.
　延伸後、光学フィルムの端部をスリッター１３により製品となる幅にスリットして裁ち落とした後、エンボスリング１４及びバックロール１５よりなるナール加工装置によりナール加工（エンボッシング加工）をフィルム両端部に施し、巻取り機１６によって巻き取ることにより、光学フィルム（元巻き）Ｆ中の貼り付きや、すり傷の発生を防止する。ナール加工の方法は、凸凹のパターンを側面に有する金属リングを加熱や加圧により加工することができる。なお、フィルム両端部のクリップの把持部分は通常、変形しており、フィルム製品として使用できないので、切除されて、原料として再利用される。 After stretching, after slitting the edge of the optical film to a product width with a slitter 13, the film is subjected to knurling (embossing) on both ends of the film by a knurling device comprising an embossing ring 14 and a back roll 15. By winding by the winder 16, the sticking in the optical film (original winding) F and the generation of scratches are prevented. The knurling method can process a metal ring having an uneven pattern on its side surface by heating or pressing. In addition, since the grip part of the clip of the both ends of a film is deform | transforming normally and cannot be used as a film product, it is cut out and reused as a raw material.
　次に、光学フィルムの巻取り工程は、円筒形巻き光学フィルムの外周面とこれの直前の移動式搬送ロールの外周面との間の最短距離を一定に保持しながらフィルムを巻取りロールに巻き取るものである。かつ巻取りロールの手前には、光学フィルムの表面電位を除去または低減する除電ブロア等の手段が設けられている。 Next, in the winding process of the optical film, the film is wound around the winding roll while keeping the shortest distance between the outer circumferential surface of the cylindrically wound optical film and the outer circumferential surface of the movable transport roll immediately before this. It is what you take. In addition, a means such as a static elimination blower for removing or reducing the surface potential of the optical film is provided in front of the winding roll.
　本発明の光学フィルムの製造に係わる巻き取り機は一般的に使用されているものでよく、定テンション法、定トルク法、テーパーテンション法、内部応力一定のプログラムテンションコントロール法等の巻き取り方法で巻き取ることができる。 The winder related to the production of the optical film of the present invention may be generally used, and it may be a winding method such as a constant tension method, a constant torque method, a taper tension method, or a program tension control method with a constant internal stress. Can be wound up.
　なお、光学フィルムの巻取り時の初期巻取り張力が９０．２～３００．８Ｎ／ｍであるのが好ましい。 The initial winding tension at the time of winding the optical film is preferably 90.2 to 300.8 N / m.
　本発明の方法におけるフィルムの巻き取り工程では、温度２０～３０℃、湿度２０～６０％ＲＨの環境条件にて、フィルムを巻き取ることが好ましい。このように、光学フィルムの巻き取り工程での温度及び湿度を規定することにより、厚み方向リターデーション（Ｒｔ）の湿度変化の耐性が向上する。 In the film winding step in the method of the present invention, the film is preferably wound under environmental conditions of a temperature of 20 to 30 ° C. and a humidity of 20 to 60% RH. Thus, the tolerance of the humidity change of the thickness direction retardation (Rt) improves by prescribing | regulating the temperature and humidity in the winding-up process of an optical film.
　巻き取り工程における温度が２０℃未満であれば、シワが発生し、フィルム巻品質劣化のため実用に耐えないので、好ましくない。 If the temperature in the winding process is less than 20 ° C., wrinkles are generated, and the film winding quality deteriorates and cannot be put into practical use.
　光学フィルムの巻き取り工程における温度が３０℃を超えると、やはりシワが発生し、フィルム巻品質劣化のため実用に耐えないので、好ましくない。 If the temperature in the winding process of the optical film exceeds 30 ° C., wrinkles are also generated, which is unpreferable because it cannot be put into practical use due to deterioration in film winding quality.
　また、光学フィルムの巻き取り工程における湿度が２０％ＲＨ未満であれば、帯電しやすく、フィルム巻品質劣化のため実用に耐えないので、好ましくない。 Further, if the humidity in the winding process of the optical film is less than 20% RH, it is not preferable because it is easily charged and cannot be put into practical use due to deterioration of the film winding quality.
　光学フィルムの巻き取り工程における湿度が６０％ＲＨを超えると、巻品質、貼り付き故障、搬送性が劣化するので、好ましくない。 If the humidity in the optical film winding process exceeds 60% RH, the winding quality, sticking failure, and transportability deteriorate, which is not preferable.
　光学フィルムをロール状に巻き取る際の、巻きコアとしては、円筒上のコアであれは、どのような材質のものであってもよいが、好ましくは中空プラスチックコアであり、プラスチック材料としては加熱処理温度にも耐える耐熱性プラスチックであればどのようなものであってもよく、フェノール樹脂、キシレン樹脂、メラミン樹脂、ポリエステル樹脂、エポキシ樹脂等の樹脂が挙げられる。またガラス繊維等の充填材により強化した熱硬化性樹脂が好ましい。 When winding the optical film into a roll, the wound core may be any material as long as it is a cylindrical core, but is preferably a hollow plastic core, and the plastic material is heated. Any heat-resistant plastic that can withstand the processing temperature may be used, and examples thereof include phenol resins, xylene resins, melamine resins, polyester resins, and epoxy resins. A thermosetting resin reinforced with a filler such as glass fiber is preferred.
　例えば、中空プラスチックコア：ＦＲＰ製の外径６インチ（以下、インチは２．５４ｃｍのドットの数を表す。）、内径５インチの巻きコアが用いられる。 For example, a hollow plastic core: a wound core made of FRP with an outer diameter of 6 inches (hereinafter, the inch represents the number of dots of 2.54 cm) and an inner diameter of 5 inches is used.
　これらの巻きコアへの巻き数は、１００巻き以上であることが好ましく、５００巻き以上であることが更に好ましく、巻き厚は５ｃｍ以上であることが好ましい。 The number of turns around these winding cores is preferably 100 turns or more, more preferably 500 turns or more, and the winding thickness is preferably 5 cm or more.
　本発明の光学フィルムの膜の厚さは、使用目的によって異なるが、仕上がり光学フィルムとして、１０～５００μｍが好ましい。 The film thickness of the optical film of the present invention varies depending on the purpose of use, but the finished optical film is preferably 10 to 500 μm.
　特に、下限は２０μｍ以上、好ましくは３５μｍ以上である。上限は１５０μｍ以下、好ましくは１２０μｍ以下である。特に好ましい範囲は３５～９０μｍである。 In particular, the lower limit is 20 μm or more, preferably 35 μm or more. The upper limit is 150 μm or less, preferably 120 μm or less. A particularly preferred range is 35 to 90 μm.
　本発明の光学フィルムが位相差フィルムであり偏光板保護フィルムを兼ねる場合、光学フィルムの膜厚が上記の範囲であると、ノート型パソコンやモバイル型電子機器に用いる液晶表示装置が薄型軽量化でき好ましい。 When the optical film of the present invention is a retardation film and also serves as a polarizing plate protective film, when the film thickness of the optical film is in the above range, the liquid crystal display device used for a notebook computer or a mobile electronic device can be thinned and lightened. preferable.
　一方、光学フィルムが２０μｍより薄いと、位相差フィルムとしてのリターデーションの発現が困難となり、加えてフィルムの透湿性が高くなり、偏光子を湿度から保護する能力が低下してしまうために好ましくない。 On the other hand, if the optical film is thinner than 20 μm, it is difficult to develop retardation as a retardation film, and the moisture permeability of the film is increased, and the ability to protect the polarizer from humidity is reduced. .
　本発明の光学フィルムは、長尺状のフィルムであることが好ましく、１５００ｍ、２５００ｍ、５０００ｍとより長尺化する程、偏光板加工時の製造的効果を得る。 The optical film of the present invention is preferably a long film, and as the length is increased to 1500 m, 2500 m, and 5000 m, the production effect at the time of polarizing plate processing is obtained.
　例えば、偏光板保護フィルム製造においてロール長さは、生産性と運搬性を考慮すると１０～５０００ｍ、好ましくは５０～４５００ｍである。 For example, in the production of a polarizing plate protective film, the roll length is 10 to 5000 m, preferably 50 to 4500 m in consideration of productivity and transportability.
　光学フィルムの幅は、偏光子の幅や製造ラインに適した幅を選択することができ、０．５～４．０ｍ、好ましくは０．６～３．０ｍの幅でフィルムを製造してロール状に巻き取り、偏光板加工に供してもよい。また、目的の倍幅以上のフィルムを製造してロールに巻き取った後、断裁して目的の幅のロールを得て、このようなロールを偏光板加工に用いるようにしてもよい。 The width of the optical film can be selected from the width of the polarizer and the width suitable for the production line. The roll is produced by producing a film with a width of 0.5 to 4.0 m, preferably 0.6 to 3.0 m. It may be wound into a shape and subjected to polarizing plate processing. Moreover, after manufacturing the film more than the target double width and winding up to a roll, it may cut and obtain the roll of the target width, and you may make it use such a roll for polarizing plate processing.
　前述の可塑剤、紫外線吸収剤、マット剤等の添加物濃度が異なるセルロースエステルを含む組成物を共押出しして、積層構造の光学フィルムを作製することもできる。 It is also possible to produce a laminated structure optical film by co-extruding compositions containing cellulose esters having different additive concentrations such as the above-mentioned plasticizer, ultraviolet absorber and matting agent.
　例えば、スキン層／コア層／スキン層といった構成の光学フィルムを作ることができる。 For example, an optical film having a structure of skin layer / core layer / skin layer can be produced.
　例えば、マット剤は、スキン層に多く、またはスキン層のみに入れることができる。 For example, a lot of matting agent can be contained in the skin layer or only in the skin layer.
　可塑剤、紫外線吸収剤はスキン層よりもコア層に多く入れることができ、コア層のみに入れてもよい。 Plasticizers and UV absorbers can be added more in the core layer than in the skin layer, and may be added only in the core layer.
　また、コア層とスキン層で可塑剤、紫外線吸収剤の種類を変更することもでき、例えば、スキン層に低揮発性の可塑剤及び／または紫外線吸収剤を含ませ、コア層に可塑性に優れた可塑剤、或いは紫外線吸収性に優れた紫外線吸収剤を添加することもできる。 In addition, the type of plasticizer and ultraviolet absorber can be changed between the core layer and the skin layer. For example, the skin layer contains a low-volatile plasticizer and / or an ultraviolet absorber, and the core layer has excellent plasticity. It is also possible to add a plasticizer or an ultraviolet absorber excellent in ultraviolet absorption.
　スキン層とコア層のガラス転移温度が異なっていてもよく、スキン層のガラス転移温度よりコア層のガラス転移温度が低いことが好ましい。 The glass transition temperature of the skin layer and the core layer may be different, and the glass transition temperature of the core layer is preferably lower than the glass transition temperature of the skin layer.
　このとき、スキンとコアの両者のガラス転移温度を測定し、これらの体積分率より算出した平均値を上記ガラス転移温度Ｔｇと定義して同様に扱うこともできる。 At this time, the glass transition temperature of both the skin and the core can be measured, and the average value calculated from these volume fractions can be defined as the glass transition temperature Tg and similarly handled.
　また、溶融流延時のセルロースエステルを含む溶融物の粘度もスキン層とコア層で異なっていてもよく、スキン層の粘度＞コア層の粘度でも、コア層の粘度≧スキン層の粘度でもよい。 Also, the viscosity of the melt containing the cellulose ester at the time of melt casting may be different between the skin layer and the core layer, and the viscosity of the skin layer> the viscosity of the core layer or the viscosity of the core layer ≧ the viscosity of the skin layer may be sufficient.
　《リサイクル》
　製膜工程において、カットされたフィルム両端のクリップ把持部分は、粉砕処理された後、或いは必要に応じて造粒処理を行った後、同じ品種のフィルム用原料としてまたは異なる品種のフィルム用原料として再利用することが好ましい。 "recycling"
In the film forming process, the clip gripping portions at both ends of the cut film are pulverized or granulated as necessary, and then used as a film material of the same product type or as a film material of a different product type. It is preferable to reuse.
　《機能性層》
　本発明の光学フィルム製造に際し、延伸の前及び／または後で帯電防止層、透明導電層、ハードコート層、反射防止層、防汚層、易滑性層、易接着層、防眩層、ガスバリア層、光学補償層等の機能性層を塗設してもよい。 《Functional layer》
In producing the optical film of the present invention, before and / or after stretching, an antistatic layer, a transparent conductive layer, a hard coat layer, an antireflection layer, an antifouling layer, a slippery layer, an easy adhesion layer, an antiglare layer, and a gas barrier. A functional layer such as a layer or an optical compensation layer may be provided.
　特に、帯電防止層、ハードコート層、反射防止層、易接着層、防眩層及び光学補償層から選ばれる少なくとも１層を設けることが好ましい。この際、コロナ放電処理、プラズマ処理、薬液処理等の各種表面処理を必要に応じて施すことができる。 In particular, it is preferable to provide at least one layer selected from an antistatic layer, a hard coat layer, an antireflection layer, an easy adhesion layer, an antiglare layer and an optical compensation layer. At this time, various surface treatments such as corona discharge treatment, plasma treatment, and chemical treatment can be performed as necessary.
　《ケン化》
　本発明の光学フィルムはケン化処理適性に優れるが、ケン化処理はフィルムをケン化液に浸漬してもよく（浸漬法）、ケン化液を塗布してもよい（塗布法）。 Saponification
The optical film of the present invention is excellent in suitability for saponification treatment. In the saponification treatment, the film may be immersed in a saponification solution (immersion method) or a saponification solution may be applied (application method).
　（アルカリ溶液）
　本発明の光学フィルムは、濃度が２ｍｏｌ／Ｌ以上のアルカリ溶液をケン化液として用いてケン化処理されることが好ましい。前記ケン化液はアルカリ剤と水とからなり、場合により界面活性剤および相溶化剤が含有されていてもよい。 (Alkaline solution)
The optical film of the present invention is preferably saponified using an alkaline solution having a concentration of 2 mol / L or more as a saponification solution. The saponification solution is composed of an alkali agent and water, and may optionally contain a surfactant and a compatibilizer.
　前記アルカリ溶液の濃度（アルカリ溶液中のアルカリ剤の含有量）は、セルロースエステルのアシル置換度に応じて決定する必要がある。 The concentration of the alkaline solution (content of the alkaline agent in the alkaline solution) needs to be determined according to the acyl substitution degree of the cellulose ester.
　すなわち、セルロースエステルにおいては、アシル基の炭素数増大に伴って、ケン化効率が著しく低下するため、アシル基の炭素数が大きくなるほどアルカリ濃度は高くする必要があるが、アルカリ濃度が高すぎるとアルカリ溶液の安定性が損なわれ、長時間塗布において析出する場合もあるため、セルロースエステルの構造に応じて適切にアルカリ溶液を選定する必要はあるものの、アルカリ濃度は低い方が好ましい。 That is, in the cellulose ester, as the carbon number of the acyl group increases, the saponification efficiency decreases remarkably. Therefore, the alkali concentration needs to be increased as the carbon number of the acyl group increases, but if the alkali concentration is too high, Since the stability of the alkaline solution is impaired and may precipitate during long-time application, it is necessary to appropriately select an alkaline solution according to the structure of the cellulose ester, but a lower alkali concentration is preferable.
　また、セルロースエステル中にアルカリ加水分解性の添加剤を含有する場合、それが分解するためアルカリ濃度が高すぎるのは好ましくない。 Further, when an alkali hydrolyzable additive is contained in the cellulose ester, it is not preferable that the alkali concentration is too high because it decomposes.
　従って、本発明で用いられるアルカリ溶液は２ｍｏｌ／Ｌ～４．０ｍｏｌ／Ｌであることが好ましく、２ｍｏｌ／Ｌ～２．５ｍｏｌ／Ｌであることがより好ましい。 Therefore, the alkaline solution used in the present invention is preferably 2 mol / L to 4.0 mol / L, more preferably 2 mol / L to 2.5 mol / L.
　本発明では、ケン化処理温度が４０℃～８０℃の温度で行われることが好ましく、さらに好ましいのは４０℃～７０℃であり、より好ましいのは４０℃～６５℃である。 In the present invention, the saponification treatment temperature is preferably 40 ° C. to 80 ° C., more preferably 40 ° C. to 70 ° C., and still more preferably 40 ° C. to 65 ° C.
　ケン化温度が４０℃以上であれば、セルロースエステル表面のケン化が進みやすく、偏光子との接着性が得られやすいため、良好な耐久性を有する偏光板を製造しやすくなる。 If the saponification temperature is 40 ° C. or higher, saponification of the cellulose ester surface is likely to proceed, and adhesion with a polarizer can be easily obtained, so that it becomes easy to produce a polarizing plate having good durability.
　一方、ケン化処理温度が高すぎると、アシレートフィルム中の成分（可塑剤など）が抽出されたり、或いは分解したり、更にはフィルムの過度の膨潤が起こる場合があり、フィルム面状に白化などの問題が生じてしまうことがある。 On the other hand, if the saponification temperature is too high, components (such as plasticizers) in the acylate film may be extracted or decomposed, and the film may be excessively swollen. Problems may occur.
　本発明に用いられるアルカリ剤の例として、水酸化ナトリウム、同カリウム、同リチウム、同アンモニウム、第３リン酸ナトリウム、同カリウム、同アンモニウム、第二リン酸ナトリウム、同カリウム、同アンモニウム、炭酸アンモニウム、炭酸水素アンモニウム、ほう酸ナトリウム、同カリウム、同アンモニウム、などの無機アルカリ剤が挙げられる。 Examples of alkaline agents used in the present invention include sodium hydroxide, potassium, lithium, ammonium, tribasic sodium phosphate, potassium, ammonium, dibasic sodium phosphate, potassium, ammonium, ammonium carbonate. Inorganic alkali agents such as ammonium hydrogen carbonate, sodium borate, potassium, ammonium and the like.
　また、モノメチルアミン、ジメチルアミン、トリメチルアミン、モノエチルアミン、ジエチルアミン、トリエチルアミン、モノイソプロピルアミン、ジイソプロピルアミン、トリイソプロピルアミン、ｎ－ブチルアミン、モノエタノールアミン、ジエタノールアミン、トリエタノールアミン、モノイソプロパノールアミン、ジイソプロパノールアミン、エチレンイミン、エチレンジアミン、ピリジン、ＤＢＵ（１，８－ジアザビシクロ［５，４，０］－７－ウンデセン）、ＤＢＮ（１，５－ジアザビシクロ［４，３，０］－５－ノネン）、テトラメチルアンモニウムヒドロキシド、テトラエチルアンモニウムヒドロキシド、テトラプロピルアンモニウムヒドロキシド、テトラブチルアンモニウムヒドロキシド、トリエチルブチルアンモニウムヒドロキシドなどの有機アルカリ剤も用いられる。これらのアルカリ剤は単独もしくは二種以上を組み合わせて併用することもでき、一部を例えばハロゲン化したような塩の形で添加してもよい。 Also, monomethylamine, dimethylamine, trimethylamine, monoethylamine, diethylamine, triethylamine, monoisopropylamine, diisopropylamine, triisopropylamine, n-butylamine, monoethanolamine, diethanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, Ethyleneimine, ethylenediamine, pyridine, DBU (1,8-diazabicyclo [5,4,0] -7-undecene), DBN (1,5-diazabicyclo [4,3,0] -5-nonene), tetramethylammonium Hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, triethylbutylammonium Organic alkali agents such as hydroxides may also be used. These alkali agents can be used alone or in combination of two or more, and a part of them may be added in the form of a salt, for example, halogenated.
　これらのアルカリ剤の中でも、水酸化ナトリウム、水酸化カリウムが好ましい。その理由は、これらの量を調整することにより広いｐＨ領域でのｐＨ調整が可能となるためである。 Among these alkali agents, sodium hydroxide and potassium hydroxide are preferable. The reason is that the pH can be adjusted in a wide pH range by adjusting these amounts.
　前記アルカリ溶液の溶媒は、水の単独溶媒、もしくは水と有機溶媒との混合溶媒である。好ましい有機溶媒は、アルコール類、アルカノール類、グリコール化合物のモノエーテル類、ケトン類、アミド類、スルホキシド類、エーテル類が挙げられ、より好ましくは、分子量６１以上のアルコール類であり、さらに好ましくは分子量６１以上のグリコール類であり、具体的には、エチレングリコール、プロピレングリコール、ブタンジオール、ペンタンジオール、ヘキサンジオール、グリセリンモノメチルエーテル、グリセリンモノエチルエーテル、シクロヘキサンジオール、シクロヘキサンジメタノール、ジエチレングリコール、ジプロピレングリコール等が挙げられる。水と併用される有機溶媒は、単独もしくは２種類以上を混合して用いてもよい。 The solvent of the alkaline solution is a single solvent of water or a mixed solvent of water and an organic solvent. Preferred organic solvents include alcohols, alkanols, monoethers of glycol compounds, ketones, amides, sulfoxides, ethers, more preferably alcohols having a molecular weight of 61 or more, more preferably molecular weights. 61 or more glycols, specifically, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, glycerol monomethyl ether, glycerol monoethyl ether, cyclohexanediol, cyclohexanedimethanol, diethylene glycol, dipropylene glycol, etc. Is mentioned. You may use the organic solvent used together with water individually or in mixture of 2 or more types.
　（ケン化処理）
　上述のように本発明の光学フィルムは、フィルムを前記アルカリ溶液でケン化処理する工程と、アルカリ溶液をフィルムから洗い落とす工程とによりアルカリケン化処理が実施されることが好ましい。 (Saponification treatment)
As described above, the optical film of the present invention is preferably subjected to the alkali saponification treatment by the step of saponifying the film with the alkali solution and the step of washing off the alkali solution from the film.
　その後、アルカリ溶液を中和する工程、および中和液をフィルムから洗い落とす工程を含んでもよい。 Thereafter, a step of neutralizing the alkaline solution and a step of washing off the neutralized solution from the film may be included.
　これらの工程は、フィルムを搬送しながら実施することが好ましく、特開２００１－１８８１３０号公報記載のようなアルカリ溶液に浸漬する方法を用いてもよく、特開２００４－２０３９６５号公報記載のようなアルカリ溶液を塗布する方法を用いてもよい。 These steps are preferably carried out while transporting the film, and a method of immersing in an alkaline solution as described in JP-A No. 2001-188130 may be used, as described in JP-A No. 2004-203965. A method of applying an alkaline solution may be used.
　ケン化時間は３０秒～５分間であることが好ましく、１～２分間であることがより好ましい。ケン化時間が長すぎると、後述する偏光板耐久性に悪影響を及ぼしてしまうことがある。 The saponification time is preferably 30 seconds to 5 minutes, more preferably 1 to 2 minutes. If the saponification time is too long, the polarizing plate durability described later may be adversely affected.
　《偏光板》
　本発明の光学フィルムを偏光板保護フィルムとして用いる場合、偏光板の作製方法は特に限定されず、一般的な方法で作製することができる。 "Polarizer"
When using the optical film of this invention as a polarizing plate protective film, the preparation methods of a polarizing plate are not specifically limited, It can manufacture by a general method.
　本発明の光学フィルムの裏面側をアルカリケン化処理し、処理した光学フィルムを、ヨウ素溶液中に浸漬延伸して作製した偏光子の少なくとも一方の面に、完全ケン化型ポリビニルアルコール水溶液を用いて貼り合わせることが好ましい。 The back side of the optical film of the present invention is subjected to alkali saponification treatment, and a completely saponified polyvinyl alcohol aqueous solution is used on at least one surface of a polarizer produced by immersing and stretching the treated optical film in an iodine solution. It is preferable to bond them together.
　もう一方の面にも本発明の光学フィルムを用いても、別の偏光板保護フィルムを用いてもよい。 The optical film of the present invention may be used on the other surface, or another polarizing plate protective film may be used.
　本発明の光学フィルムに対して、もう一方の面に用いられる偏光板保護フィルムは市販の光学フィルムを用いることが出来る。 A commercially available optical film can be used as the polarizing plate protective film used on the other surface of the optical film of the present invention.
　例えば、市販の光学フィルムとして、ＫＣ８ＵＸ２Ｍ、ＫＣ４ＵＸ、ＫＣ５ＵＸ、ＫＣ４ＵＹ、ＫＣ８ＵＹ、ＫＣ１２ＵＲ、ＫＣ８ＵＣＲ－３、ＫＣ８ＵＣＲ－４、ＫＣ４ＦＲ－１、ＫＣ８ＵＹ－ＨＡ、ＫＣ８ＵＸ－ＲＨＡ（以上、コニカミノルタオプト（株）製）等が好ましく用いられる。 For example, as commercially available optical films, KC8UX2M, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UCR-3, KC8UCR-4, KC4FR-1, KC8UY-HA, KC8UX-RHA (above, Konica Minolta Opto) Etc. are preferably used.
　或いは更にディスコチック液晶、棒状液晶、コレステリック液晶などの液晶化合物を配向させて形成した光学異方層を有している光学補償フィルムを兼ねる偏光板保護フィルムを用いることも好ましい。例えば、特開２００３－９８３４８号記載の方法で光学異方性層を形成することが出来る。本発明の光学フィルムと組み合わせて使用することによって、平面性に優れ、安定した視野角拡大効果を有する偏光板を得ることが出来る。 Alternatively, it is also preferable to use a polarizing plate protective film that also serves as an optical compensation film having an optical anisotropic layer formed by aligning liquid crystal compounds such as discotic liquid crystal, rod-shaped liquid crystal, and cholesteric liquid crystal. For example, the optically anisotropic layer can be formed by the method described in JP-A-2003-98348. By using in combination with the optical film of the present invention, a polarizing plate having excellent flatness and a stable viewing angle expansion effect can be obtained.
　或いは、光学フィルム以外の環状オレフィン樹脂、アクリル樹脂、ポリエステル、ポリカーボネート等のフィルムをもう一方の面の偏光板保護フィルムとして用いてもよい。 Alternatively, a film such as a cyclic olefin resin other than an optical film, an acrylic resin, polyester, or polycarbonate may be used as a polarizing plate protective film on the other surface.
　上記アルカリ処理の代わりに特開平６－９４９１５号公報、同６－１１８２３２号公報に記載されているような易接着加工を施して偏光板加工を行ってもよい。 Instead of the alkali treatment, polarizing plate processing may be performed by performing easy adhesion processing as described in JP-A-6-94915 and JP-A-6-118232.
　偏光板の主たる構成要素である偏光子とは、一定方向の偏波面の光だけを通す素子であり、現在知られている代表的な偏光子は、ポリビニルアルコール系偏光フィルムで、これはポリビニルアルコール系フィルムにヨウ素を染色させたものと二色性染料を染色させたものがある。 A polarizer, which is a main component of a polarizing plate, is an element that allows only light of a plane of polarization in a certain direction to pass. A typical polarizer currently known is a polyvinyl alcohol-based polarizing film, which is polyvinyl alcohol. There are one in which iodine is dyed on a system film and one in which dichroic dye is dyed.
　偏光子は、ポリビニルアルコール水溶液を製膜し、これを一軸延伸させて染色するか、染色した後一軸延伸してから、好ましくはホウ素化合物で耐久性処理を行ったものが用いられている。偏光子の膜厚は５～４０μｍ、好ましくは５～３０μｍであり、特に好ましくは５～２０μｍである。 The polarizer is formed by forming a polyvinyl alcohol aqueous solution into a film and dyeing the film by uniaxial stretching or dyeing or uniaxially stretching, and then performing a durability treatment with a boron compound. The thickness of the polarizer is 5 to 40 μm, preferably 5 to 30 μm, and particularly preferably 5 to 20 μm.
　該偏光子の面上に、本発明の光学フィルムの片面を貼り合わせて偏光板を形成する。好ましくは完全ケン化ポリビニルアルコール等を主成分とする水系の接着剤によって貼り合わせる。 A polarizing plate is formed by bonding one side of the optical film of the present invention on the surface of the polarizer. It is preferably bonded with a water-based adhesive mainly composed of completely saponified polyvinyl alcohol or the like.
　偏光子は一軸方向（通常は流延方向）に延伸されているため、偏光板を高温高湿の環境下に置くと延伸方向（通常は流延方向）は縮み、延伸と垂直方向（通常は幅方向）には伸びる。偏光板保護用フィルムの膜厚が薄くなるほど偏光板の伸縮率は大きくなり、特に偏光子の延伸方向の収縮量が大きい。 Since the polarizer is stretched in a uniaxial direction (usually the casting direction), when the polarizing plate is placed in a high-temperature and high-humidity environment, the stretching direction (usually the casting direction) shrinks, and the direction perpendicular to the stretching (usually the casting direction) It extends in the width direction. As the thickness of the polarizing plate protective film decreases, the expansion / contraction ratio of the polarizing plate increases, and in particular, the amount of contraction in the stretching direction of the polarizer increases.
　通常、偏光子の延伸方向は偏光板保護用フィルムの流延方向（ＭＤ方向）と貼り合わせるため、偏光板保護用フィルムを薄膜化する場合は、特に流延方向の伸縮率を抑えることが重要である。本発明の光学フィルムは極めて寸法安定に優れる為、このような偏光板保護フィルムとして好適に使用される。 Normally, the direction of stretching of the polarizer is bonded to the casting direction (MD direction) of the polarizing plate protective film. Therefore, when thinning the polarizing plate protective film, it is particularly important to suppress the stretch rate in the casting direction. It is. Since the optical film of the present invention is extremely excellent in dimensional stability, it is suitably used as such a polarizing plate protective film.
　即ち、本発明の光学フィルムは６０℃、９０％ＲＨの条件での耐久性試験によっても波打ち状のむらが増加することはなく、裏面側に光学補償フィルムを有する偏光板であっても、耐久性試験後に視野角特性が変動することなく良好な視認性を提供することが出来る。 That is, the optical film of the present invention does not increase the wavy unevenness even in the durability test under the conditions of 60 ° C. and 90% RH, and even if it is a polarizing plate having an optical compensation film on the back side. It is possible to provide good visibility without changing the viewing angle characteristics after the test.
　偏光板は偏光子及びその両面を保護する保護フィルムで構成されており、更に該偏光板の一方の面にプロテクトフィルムを、反対面にセパレートフィルムを貼合して構成することが出来る。プロテクトフィルム及びセパレートフィルムは偏光板出荷時、製品検査時等において偏光板を保護する目的で用いられる。 The polarizing plate is composed of a polarizer and a protective film for protecting both surfaces of the polarizer, and can further be constructed by laminating a protective film on one surface of the polarizing plate and a separate film on the opposite surface. The protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection.
　この場合、プロテクトフィルムは、偏光板の表面を保護する目的で貼合され、偏光板を液晶板へ貼合する面の反対面側に用いられる。 In this case, the protective film is bonded for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal plate.
　また、セパレートフィルムは液晶板へ貼合する接着層をカバーする目的で用いられ、偏光板を液晶セルへ貼合する面側に用いられる。 Further, the separate film is used for the purpose of covering the adhesive layer to be bonded to the liquid crystal plate, and is used on the surface side for bonding the polarizing plate to the liquid crystal cell.
　《液晶表示装置》
　本発明の光学フィルムを用いた偏光板保護フィルム（位相差フィルムを兼ねる場合も含む）を含む偏光板は、通常の偏光板と比較して高い表示品質を発現させることができ、特にマルチドメイン型の液晶表示装置、より好ましくは複屈折モードによってマルチドメイン型の液晶表示装置への使用に適している。 <Liquid crystal display device>
A polarizing plate including a polarizing plate protective film (including a case where it also serves as a retardation film) using the optical film of the present invention can exhibit high display quality as compared with a normal polarizing plate, particularly a multi-domain type. The liquid crystal display device is more suitable for use in a multi-domain liquid crystal display device, more preferably by a birefringence mode.
　本発明の偏光板は、ＭＶＡ（Ｍｕｌｔｉ－ｄｏｍａｉｎ　Ｖｅｒｔｉｃａｌ　Ａｌｉｇｎｍｅｎｔ）モード、ＰＶＡ（Ｐａｔｔｅｒｎｅｄ　Ｖｅｒｔｉｃａｌ　Ａｌｉｇｎｍｅｎｔ）モード、ＣＰＡ（Ｃｏｎｔｉｎｕｏｕｓ　Ｐｉｎｗｈｅｅｌ　Ａｌｉｇｎｍｅｎｔ）モード、ＯＣＢ（Ｏｐｔｉｃａｌ　Ｃｏｍｐｅｎｓａｔｅｄ　Ｂｅｎｄ）モード、ＩＰＳ（Ｉｎ　Ｐｌａｃｅ　Ｓｗｉｔｃｈｉｎｇ）モード等に用いることができ、特定の液晶モード、偏光板の配置に限定されるものではない。 The polarizing plate of the present invention includes an MVA (Multi-domain Vertical Alignment) mode, a PVA (Patterned Vertical Alignment) mode, a CPA (Continuous Pinheal Alignment) mode, an OCB (Optical AlignSensing mode) It can be used, and is not limited to a specific liquid crystal mode and the arrangement of polarizing plates.
　液晶表示装置はカラー化及び動画表示用の装置としても応用されつつあり、本発明により表示品質が改良され、コントラストの改善や偏光板の耐性が向上したことにより、疲れにくく忠実な動画像表示が可能となる。 Liquid crystal display devices are being applied as devices for colorization and moving image display, and the display quality is improved by the present invention, and the improvement of contrast and the resistance of polarizing plates improve the display of moving images that are less fatigued and faithful. It becomes possible.
　本発明の光学フィルムを位相差フィルム及び偏光板保護フィルムとして含む偏光板は、液晶セルに対して、一枚配置するか或いは液晶セルの両側に二枚配置する。このとき偏光板の該位相差フィルム側が液晶表示装置の液晶セルに面するように用いることで表示品質の向上に寄与できる。図７においては２２ａ及び２２ｂのフィルムが液晶表示装置の液晶セルに面することになる。このような構成において、本発明の光学フィルムは、液晶セルを光学的に補償することができる。 The polarizing plate including the optical film of the present invention as a retardation film and a polarizing plate protective film is disposed on the liquid crystal cell, or on the both sides of the liquid crystal cell. At this time, the use of the polarizing plate so that the retardation film side faces the liquid crystal cell of the liquid crystal display device can contribute to improvement in display quality. In FIG. 7, the films 22a and 22b face the liquid crystal cell of the liquid crystal display device. In such a configuration, the optical film of the present invention can optically compensate the liquid crystal cell.
　本発明の偏光板を液晶表示装置に用いる場合は、液晶表示装置の偏光板の内の少なくとも一つの偏光板を、本発明の偏光板とすればよい。本発明の偏光板を用いることで、表示品質が向上し、視野角特性に優れた液晶表示装置が提供できる。 When the polarizing plate of the present invention is used for a liquid crystal display device, at least one of the polarizing plates of the liquid crystal display device may be the polarizing plate of the present invention. By using the polarizing plate of the present invention, a liquid crystal display device with improved display quality and excellent viewing angle characteristics can be provided.
　以下に実施例を挙げて本発明を具体的に説明するが、本発明はこれらに限定されるものではない。 Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.
　〈セルロースエステルの合成〉
　（セルロースエステル１の合成）
　セルロース（日本製紙（株）製溶解パルプ）３０ｇに酢酸２０ｇ、及びプロピオン酸８０ｇを加え、５０～５５℃で３０分撹拌した。混合物を冷却した後、氷浴中で冷却した無水酢酸１０ｇ、無水プロピオン酸１００ｇ、及び硫酸１．２ｇを加えてエステル化を行った。エステル化において、４０℃を超えないように調節しながら、撹拌を１５０分行った。反応終了後、酢酸３０ｇと水１０ｇの混合液を２０分かけて滴下して過剰の無水物を加水分解した。反応液の温度を４０℃に保持しながら、酢酸９０ｇと水３０ｇを加えて１時間撹拌した。酢酸マグネシウム２ｇを含有した水溶液中に混合物をあけてしばらく撹拌した後にろ過、洗浄液のｐＨが中性になるまで十分水で洗浄した後、乾燥し、セルロースエステル１を得た。得られたセルロースエステル１に関して、前述のＡＳＴＭ　Ｄ８１７－９６に規定の方法によりアセチル基の置換度（Ｘ）、及びプロピオニル基の置換度（Ｙ）を求めたところ、Ｘ＝０．８０、Ｙ＝１．７０であった。これにより総置換度（Ｘ＋Ｙ）は２．５０、総炭素数（２×Ｘ＋３×Ｙ）は６．７０と計算できる。また、前述の条件でゲルパーミエーションクロマトグラフィーにより重量平均分子量（Ｍｗ）を求めたところ、２１００００であった。 <Synthesis of cellulose ester>
(Synthesis of cellulose ester 1)
20 g of acetic acid and 80 g of propionic acid were added to 30 g of cellulose (dissolved pulp manufactured by Nippon Paper Industries Co., Ltd.), and the mixture was stirred at 50 to 55 ° C. for 30 minutes. After the mixture was cooled, esterification was performed by adding 10 g of acetic anhydride, 100 g of propionic anhydride, and 1.2 g of sulfuric acid cooled in an ice bath. Stirring was performed for 150 minutes while adjusting the esterification so as not to exceed 40 ° C. After completion of the reaction, a mixture of 30 g of acetic acid and 10 g of water was added dropwise over 20 minutes to hydrolyze excess anhydride. While maintaining the temperature of the reaction solution at 40 ° C., 90 g of acetic acid and 30 g of water were added and stirred for 1 hour. The mixture was poured into an aqueous solution containing 2 g of magnesium acetate, stirred for a while, filtered, sufficiently washed with water until the pH of the washing solution became neutral, and then dried to obtain cellulose ester 1. With respect to the obtained cellulose ester 1, when the substitution degree (X) of the acetyl group and the substitution degree (Y) of the propionyl group were determined by the method prescribed in the aforementioned ASTM D817-96, X = 0.80, Y = 1.70. Accordingly, the total degree of substitution (X + Y) can be calculated as 2.50, and the total number of carbons (2 × X + 3 × Y) can be calculated as 6.70. Moreover, it was 210000 when the weight average molecular weight (Mw) was calculated | required by the gel permeation chromatography on the above-mentioned conditions.
　（セルロースエステル２～１２の合成）
　セルロースエステル１の合成に対して、酢酸、無水酢酸、プロピオン酸、及び無水プロピオン酸の使用量を変化させた以外はセルロースエステル１の合成と同様の合成操作を行い、セルロースエステル２～１２を得た。 (Synthesis of cellulose esters 2 to 12)
Cellulose esters 2 to 12 were obtained in the same manner as the synthesis of cellulose ester 1, except that the amounts of acetic acid, acetic anhydride, propionic acid, and propionic anhydride used were changed. It was.
　本発明のセルロースエステル１～１２の各々に対し、アセチル基の置換度（Ｘ）、プロピオニル基の置換度（Ｙ）、総置換度（Ｘ＋Ｙ）、総炭素数（２×Ｘ＋３×Ｙ）、及び重量平均分子量（Ｍｗ）の値を表１に示す。 For each of the cellulose esters 1 to 12 of the present invention, the degree of substitution of the acetyl group (X), the degree of substitution of the propionyl group (Y), the total degree of substitution (X + Y), the total number of carbons (2 × X + 3 × Y), and Table 1 shows the value of the weight average molecular weight (Mw).
　（比較のセルロースエステル１３～２４の合成）
　比較のセルロースエステル１３～２２は、セルロースエステル１の合成に対して、酢酸、無水酢酸、プロピオン酸、及び無水プロピオン酸の使用量を変化させた以外はセルロースエステル１と同様の合成操作を行うことにより合成した。一方、比較のセルロースエステル２３、２４は、セルロースエステル１の合成に対して、酢酸、無水酢酸、酪酸、及び無水酪酸の組み合わせを用い、さらにそれらの使用量を変化させた以外はセルロースエステル１と同様の合成操作を行うことによって合成した。 (Synthesis of comparative cellulose esters 13 to 24)
Comparative cellulose esters 13 to 22 are synthesized in the same manner as cellulose ester 1 except that the amount of acetic acid, acetic anhydride, propionic acid, and propionic anhydride used is changed. Was synthesized. On the other hand, the comparative cellulose esters 23 and 24 are the same as the cellulose ester 1 except that a combination of acetic acid, acetic anhydride, butyric acid and butyric anhydride is used for the synthesis of the cellulose ester 1 and the amount used is further changed. The synthesis was performed by performing the same synthesis operation.
　得られた比較のセルロースエステル１３～２４の各々に対し、アセチル基の置換度（Ｘ）、プロピオニル基の置換度（Ｙ）、総置換度（Ｘ＋Ｙ）、総炭素数（２×Ｘ＋３×Ｙ）もしくはブチリル基の置換度（Ｚ）、総置換度（Ｘ＋Ｚ）、総炭素数（２×Ｘ＋４×Ｚ）、及び重量平均分子量（Ｍｗ）の値を表１に示す。 For each of the obtained comparative cellulose esters 13 to 24, the degree of acetyl group substitution (X), the degree of propionyl group substitution (Y), the total degree of substitution (X + Y), the total number of carbons (2 × X + 3 × Y) Alternatively, Table 1 shows values of the butyryl group substitution degree (Z), total substitution degree (X + Z), total carbon number (2 × X + 4 × Z), and weight average molecular weight (Mw).
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
　実施例１
　〔セルロースエステルを有してなる光学フィルム（以下、単にセルロースエステルフィルムと称する）試料Ｆ－１の作製〕
　下記のように、上記合成したセルロースエステルと各種添加剤を用いて溶融流延により、本発明のセルロースエステルフィルムＦ－１を作製した。 Example 1
[Production of Optical Film Containing Cellulose Ester (hereinafter simply referred to as Cellulose Ester Film) Sample F-1]
As described below, the cellulose ester film F-1 of the present invention was produced by melt casting using the synthesized cellulose ester and various additives.
　セルロースエステル１　　　　　　　　　　　　　　　　１００質量部
　可塑剤－Ａ　　　　　　　　　　　　　　　　　　　　　　　８質量部
　ＩＲＧＡＮＯＸ１０１０（チバ・ジャパン社製）　　　０．５０質量部
　ＧＳＹ－Ｐ１０１（堺化学工業社製）　　　　　　　　０．２５質量部
　ＳｕｍｉｌｉｚｅｒＧＳ（住友化学社製）　　　　　　０．２５質量部
　ＴＩＮＵＶＩＮ９２８（チバ・ジャパン社製）　　　　　１．５質量部
　アエロジルＮＡＸ５０（日本アエロジル社製）　　　　　０．２質量部
　ＫＥ－Ｐ１００　（日本触媒社製）　　　　　　　　　０．０２質量部
　上記のセルロースエステル、添加剤を混合し、６０℃　５時間減圧乾燥した。このセルロースエステル組成物を、２軸式押出し機を用いて２３５℃で溶融混合しペレット化した。 Cellulose ester 1 100 parts by weight Plasticizer-A 8 parts by weight IRGANOX 1010 (manufactured by Ciba Japan) 0.50 parts by weight GSY-P101 (manufactured by Sakai Chemical Industry) 0.25 parts by weight Sumizer GS (manufactured by Sumitomo Chemical Co., Ltd.) 0. 25 parts by mass TINUVIN 928 (manufactured by Ciba Japan) 1.5 parts by mass Aerosil NAX50 (manufactured by Nippon Aerosil Co., Ltd.) 0.2 parts by mass KE-P100 (manufactured by Nippon Shokubai Co., Ltd.) 0.02 parts by mass The above cellulose ester and additives Were mixed and dried under reduced pressure at 60 ° C. for 5 hours. This cellulose ester composition was melt-mixed at 235 ° C. using a twin-screw extruder and pelletized.
　次に、本発明の光学フィルムの製造方法を実施する装置の１つの実施形態を示す概略フローシートを図２に示し、図２を用いて製造方法を説明する。 Next, a schematic flow sheet showing one embodiment of an apparatus for carrying out the method for producing an optical film of the present invention is shown in FIG. 2, and the production method will be described with reference to FIG.
　上記で得られたペレットを、１００℃、４時間乾燥を行った後、窒素雰囲気下、２５０℃で加熱溶融した後、Ｔ型流延ダイ４から第１冷却ロール５上に押し出し、第１冷却ロール５と弾性を有するタッチロール６との間にフィルムを挟圧して成形した。 The pellets obtained above were dried at 100 ° C. for 4 hours, then heated and melted at 250 ° C. in a nitrogen atmosphere, and then extruded from the T-type casting die 4 onto the first cooling roll 5 for the first cooling. A film was sandwiched between the roll 5 and the elastic touch roll 6 to form.
　その後、第２冷却ロール７及び第３冷却ロール８を介した後に、１６５℃加熱してロール延伸により、流延方向（ＭＤ方向）に１．７倍延伸し、続いて予熱ゾーン、延伸ゾーン、保持ゾーン、冷却ゾーン（各ゾーン間には各ゾーン間の断熱を確実にするためのニュートラルゾーンも有する）を有するテンターに導入し、幅方向（ＴＤ方向）に１６５℃で１．８倍延伸した後、幅方向に２％緩和しながら７０℃まで冷却し、その後クリップから開放し、クリップ把持部を裁ち落として、フィルム両端に幅１０ｍｍ、高さ５μｍのナーリング加工を施し、巻き取り張力２２０Ｎ／ｍ、テーパー４０％で巻芯に巻き取った。この際、予熱温度、保持温度を調整し延伸によるボーイング現象を防止した。仕上がりのフィルム幅は、１９６０ｍｍ幅、巻長は３２００ｍ、膜厚４０μｍの光学フィルムＦ－１を作製した。 Thereafter, after passing through the second cooling roll 7 and the third cooling roll 8, it is heated at 165 ° C. and stretched by 1.7 times in the casting direction (MD direction) by roll stretching, followed by a preheating zone, a stretching zone, It was introduced into a tenter having a holding zone and a cooling zone (there is also a neutral zone for ensuring heat insulation between the zones), and stretched 1.8 times at 165 ° C. in the width direction (TD direction). Then, it was cooled to 70 ° C. while relaxing 2% in the width direction, then released from the clip, the clip gripping part was cut off, a knurling process with a width of 10 mm and a height of 5 μm was applied to both ends of the film, and a winding tension of 220 N / m, wound around the core with a taper of 40%. At this time, the preheating temperature and the holding temperature were adjusted to prevent the bowing phenomenon due to stretching. An optical film F-1 having a finished film width of 1960 mm, a winding length of 3200 m, and a film thickness of 40 μm was produced.
　第１冷却ロール及び第２冷却ロールは直径４０ｃｍのステンレス製とし、表面にハードクロムメッキを施した。又、内部には温度調整用のオイルを循環させて、ロール表面温度を制御した。 The first cooling roll and the second cooling roll were made of stainless steel having a diameter of 40 cm, and the surface was subjected to hard chrome plating. Further, oil for temperature adjustment was circulated inside to control the roll surface temperature.
　弾性を有するタッチロール６は、直径２０ｃｍとし、内筒と外筒はステンレス製とし、外筒の表面にはハードクロムメッキを施した。外筒の肉厚は２ｍｍとし、内筒と外筒との間の空間に温度調整用のオイルを循環させて弾性を有するタッチロール６の表面温度を制御した。 The touch roll 6 having elasticity has a diameter of 20 cm, the inner cylinder and the outer cylinder are made of stainless steel, and the surface of the outer cylinder is subjected to hard chrome plating. The wall thickness of the outer cylinder was 2 mm, and temperature adjusting oil was circulated in the space between the inner cylinder and the outer cylinder to control the surface temperature of the touch roll 6 having elasticity.
　なお、弾性を有するタッチロールの表面温度は１３０℃、第１冷却ロールの表面温度は１３０℃、第２冷却ロールの表面温度は１００℃とした。弾性を有するタッチロール、第１冷却ロール、第２冷却ロールの各ロールの表面温度は、ロールにフィルムが最初に接する位置から回転方向に対して９０°手前の位置のロール表面の温度を非接触温度計を用いて幅方向に１０点測定した平均値を各ロールの表面温度とした。 The surface temperature of the elastic touch roll was 130 ° C., the surface temperature of the first cooling roll was 130 ° C., and the surface temperature of the second cooling roll was 100 ° C. The surface temperature of each roll of the touch roll having elasticity, the first cooling roll, and the second cooling roll is not in contact with the temperature of the roll surface at a position 90 ° before the rotation direction from the position where the film first contacts the roll. The average value measured at 10 points in the width direction using a thermometer was defined as the surface temperature of each roll.
　巻芯の大きさは、内径１５２ｍｍ、外径１８０ｍｍ、長さ２．１ｍの物を用いた。この巻芯母材として、エポキシ樹脂をガラス繊維、カーボン樹脂に含浸させたプリプレグ樹脂を用いた。巻芯表面にはエポキシ導電性樹脂をコーティングし、表面を研磨して、表面粗さＲａは０．３ミクロンに仕上げた。 As the size of the winding core, an inner diameter of 152 mm, an outer diameter of 180 mm, and a length of 2.1 m were used. As the core material for the core, a prepreg resin in which an epoxy resin was impregnated with glass fiber or carbon resin was used. The surface of the core was coated with an epoxy conductive resin, the surface was polished, and the surface roughness Ra was finished to 0.3 microns.
　同様に以下、本発明のセルロースエステル１、延伸倍率を下記表２に記載のセルロースエステル、条件に変更する以外は同様にして、本発明の光学フィルムＦ－２～１２、比較の光学フィルムＦ－１３～２４を作製した。 Similarly, the following is the same for the optical film F-2 to 12 of the present invention and the comparative optical film F- except that the cellulose ester 1 of the present invention is changed to the cellulose ester and conditions shown in Table 2 below. 13 to 24 were produced.
　なお、延伸倍率を変更する場合は、延伸後の仕上がりフィルムの膜厚が４０μｍになるようにＴダイのリップクリアランスを変更した。 When changing the draw ratio, the lip clearance of the T die was changed so that the film thickness of the finished film after drawing was 40 μm.
　実施例１で使用した可塑剤－Ａ、ＩＲＧＡＮＯＸ１０１０、ＧＳＹ－Ｐ１０１、ＳｕｍｉｌｉｚｅｒＧＳ、及びＴＩＮＵＶＩＮ９２８の構造は下記の通りである。なお、セルロースエステル１～２２はセルロースアセテートプロピオネートであり、セルロースエステル２３、２４はセルロースアセテートブチレートである。 The structures of plasticizer-A, IRGANOX 1010, GSY-P101, Sumilizer GS, and TINUVIN 928 used in Example 1 are as follows. Cellulose esters 1 to 22 are cellulose acetate propionate, and cellulose esters 23 and 24 are cellulose acetate butyrate.
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
　《光学フィルムの評価》
　上記のようにして作製した試料について、以下に記載した評価を行った。その結果を表２に示す。 << Evaluation of optical film >>
The samples described above were evaluated as described below. The results are shown in Table 2.
　《リターデーション値》
　得られたセルロースエステルフィルム試料の幅手方向の中央部のリターデーション値を測定した。測定には自動複屈折計ＫＯＢＵＲＡ・２１ＡＤＨ（王子計測器（株）製）を用いて、２３℃、５５％ＲＨの環境下で、波長が５９０ｎｍにおいて、試料の幅手方向に１ｃｍ間隔で３次元複屈折率測定を行い、測定値を次式に代入して求めた。 《Retardation value》
The retardation value of the center part of the width direction of the obtained cellulose-ester film sample was measured. For measurement, an automatic birefringence meter KOBURA 21ADH (manufactured by Oji Scientific Instruments Co., Ltd.) is used and is three-dimensionally spaced at 1 cm intervals in the width direction of the sample at a wavelength of 590 nm in an environment of 23 ° C. and 55% RH. The birefringence was measured, and the measured value was substituted into the following equation.
　面内リターデーションＲｏ＝（ｎｘ－ｎｙ）×ｄ
　厚み方向リターデーションＲｔ＝（（ｎｘ＋ｎｙ）／２－ｎｚ）×ｄ
　式中、ｄはフィルムの厚み（ｎｍ）、屈折率ｎｘ（フィルムの面内の最大の屈折率、遅相軸方向の屈折率ともいう）、ｎｙ（フィルム面内で遅相軸に直角な方向の屈折率）、ｎｚ（厚み方向におけるフィルムの屈折率）である。 In-plane retardation Ro = (nx−ny) × d
Thickness direction retardation Rt = ((nx + ny) / 2−nz) × d
In the formula, d is the thickness (nm) of the film, the refractive index nx (the maximum refractive index in the plane of the film, also referred to as the refractive index in the slow axis direction), ny (the direction perpendicular to the slow axis in the film plane). ) (Refractive index of the film in the thickness direction).
　《膜厚ムラ》
　得られたセルロースエステルフィルムについて、長手、幅手の膜厚をそれぞれ５ｃｍ毎に１０点ずつ、東洋精機社製デジマイクロで測定し、標準偏差を算出した。下記基準に従って評価を行った。 <Uneven film thickness>
About the obtained cellulose-ester film, the film thickness of a length and a width | variety was measured 10 points | pieces for every 5 cm with the Digimicro by Toyo Seiki Co., Ltd., and the standard deviation was computed. Evaluation was performed according to the following criteria.
　Ａ：標準偏差が０～１μｍ未満
　Ｂ：標準偏差が１～２μｍ未満
　Ｃ：標準偏差が２～５μｍ未満
　Ｄ：標準偏差が５μｍ以上
　ここで、Ａ，Ｂが実用上問題ないレベルと判断した。 A: The standard deviation is 0 to less than 1 μm B: The standard deviation is less than 1 to 2 μm C: The standard deviation is less than 2 to 5 μm D: The standard deviation is 5 μm or more.
　《ヘイズ》
　セルロースエステルフィルムをヘイズ計（１００１ＤＰ型、日本電色工業（株）製）を用いて測定した結果から、試料の厚さが４０μｍの場合のヘイズの値に比例的に換算し（例、２０μｍにおいて１％ならば、４０μｍ換算で２％ということ）、下記基準に従って評価を行った。 《Haze》
From the result of measuring the cellulose ester film using a haze meter (1001DP type, manufactured by Nippon Denshoku Industries Co., Ltd.), it was proportionally converted to the haze value when the thickness of the sample was 40 μm (eg, at 20 μm) 1% was 2% in terms of 40 μm), and the evaluation was performed according to the following criteria.
　Ａ：ヘイズが０．５％未満
　Ｂ：ヘイズが０．５～１．０％未満
　Ｃ：ヘイズが１．０～１．５％未満
　Ｄ：ヘイズが１．５％以上
　ここで、Ａ，Ｂが実用上問題ないレベルと判断した。 A: Haze is less than 0.5% B: Haze is less than 0.5 to less than 1.0% C: Haze is less than 1.0 to less than 1.5% D: Haze is more than 1.5% where A and B However, it was judged that there was no problem in practical use.
　《偏光子との密着性》
　次に、上記作製したセルロースエステルフィルムＦ－１～２４について下記のアルカリケン化処理を施した後、偏光子と貼合し、それぞれ偏光板Ｐ－１～２４を作製した。 <Adhesion with polarizer>
Next, the cellulose ester films F-1 to F-24 prepared above were subjected to the alkali saponification treatment described below, and then bonded to a polarizer to prepare polarizing plates P-1 to P-24, respectively.
　（アルカリケン化処理）
　ケン化工程：２ｍｏｌ／ＬＮａＯＨ、６０℃、６０秒
　水洗工程：水３０℃、４５秒
　中和工程：１０質量％ＨＣｌ　３０℃　４５秒
　水洗工程：水３０℃、４５秒
　ケン化処理後、水洗、中和、水洗の順に行い、次いで８０℃で乾燥した。 (Alkaline saponification treatment)
Saponification step: 2 mol / L NaOH, 60 ° C., 60 seconds Water washing step: water 30 ° C., 45 seconds Neutralization step: 10% by mass HCl 30 ° C. 45 seconds Water washing step: water 30 ° C., 45 seconds After saponification treatment, water washing, Neutralization and water washing were carried out in this order, followed by drying at 80 ° C.
　（偏光子の作製）
　厚さ１２０μｍの長尺ロールポリビニルアルコールフィルムを沃素１質量部、ホウ酸４質量部を含む水溶液１００質量部に浸漬し、５０℃で６倍に搬送方向に延伸して偏光子を作製した。 (Production of polarizer)
A 120 μm-thick long roll polyvinyl alcohol film was 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 stretched in the transport direction 6 times at 50 ° C. to produce a polarizer.
　（偏光板の作製）
　偏光子の両側に上記作製した光学フィルムを、アルカリケン化処理面を偏光子側とし完全鹸化型ポリビニルアルコール５質量％水溶液を接着剤として両面から貼合し、偏光板用保護フィルムが貼合された偏光板を作製した。 (Preparation of polarizing plate)
The above-prepared optical film is bonded to both sides of the polarizer from both sides with the alkali saponified surface as the polarizer side and a 5% by mass aqueous solution of a fully saponified polyvinyl alcohol as an adhesive, and a polarizing plate protective film is bonded. A polarizing plate was prepared.
　（密着性の評価）
　次に、これらの偏光板について、密着性評価を下記のようにして行った。 (Evaluation of adhesion)
Next, adhesion evaluation of these polarizing plates was performed as follows.
　ＪＩＳ　Ｋ　５４００に準拠した碁盤目試験を行った。具体的には一方のフィルム面上に１ｍｍ間隔で縦、横に１１本の切れ目を入れ、１ｍｍ角の碁盤目を１００個作った。この上にセロハンテープを貼り付け、９０度の角度で素早く剥がし、剥がれずに残った碁盤目の数を測定し、セルロースエステルフィルムと偏光子との密着性評価を評価した。なお、評価の基準は、次の４段階とした。 A cross-cut test based on JIS K 5400 was performed. Specifically, 11 cuts were made vertically and horizontally at intervals of 1 mm on one film surface to make 100 1 mm square grids. A cellophane tape was affixed thereon, peeled off quickly at an angle of 90 degrees, the number of grids remaining without peeling was measured, and the evaluation of adhesion between the cellulose ester film and the polarizer was evaluated. The evaluation criteria were the following four stages.
　Ａ：剥離なし
　Ｂ：剥離が５個以下
　Ｃ：剥離が６～１０個
　Ｄ：剥離が１１個以上
　ここで、Ａ，Ｂが実用上問題ないレベルと判断した。 A: No peeling B: 5 or less peelings C: 6-10 peelings D: 11 or more peelings Here, it was judged that A and B were practically no problem levels.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　以上、表２の結果から、本発明のセルロースエステルフィルムＦ－１～１２は、リターデーションの発現性に優れ、膜厚ムラが小さく、ヘイズが低く、かつ偏光子との密着性が良好な実用上優れた光学フィルムであることが分かる。これに対して、比較のセルロースエステルフィルムＦ－１３～２４は、リターデーションの発現性、膜厚の均一性、ヘイズ、及び偏光子との密着性の点ですべてを満足することができない。 As described above, from the results shown in Table 2, the cellulose ester films F-1 to F-12 of the present invention have excellent retardation, small film thickness unevenness, low haze, and good adhesion to the polarizer. It turns out that it is a superior optical film. On the other hand, the comparative cellulose ester films F-13 to F-24 cannot satisfy all of the points in terms of retardation development, film thickness uniformity, haze, and adhesion to the polarizer.
　実施例２
　表３に記載のセルロースエステル、添加剤の組み合わせ、延伸倍率に変更する以外は、実施例１のセルロースエステルフィルムＦ－１と同様な方法で、本発明のセルロースエステルフィルムＦ－２５～３６、及び比較のセルロースエステルフィルムＦ－３７、３８を作製した。更に実施例１の偏光板Ｐ－１と同様な方法で本発明の偏光板Ｐ－２５～３６、及び比較の偏光板Ｐ－３７、３８を作製した。なお、表３中の添加剤の欄に記載の括弧内の数値はセルロースエステル１００質量部に対する、用いた各添加剤の質量部を表す。 Example 2
The cellulose ester films F-25 to 36 of the present invention were prepared in the same manner as the cellulose ester film F-1 of Example 1, except that the cellulose ester and the combination of additives shown in Table 3 were changed to the draw ratio. Comparative cellulose ester films F-37 and 38 were produced. Further, polarizing plates P-25 to 36 of the present invention and comparative polarizing plates P-37 and 38 were produced in the same manner as the polarizing plate P-1 of Example 1. In addition, the numerical value in the bracket | parenthesis described in the column of the additive in Table 3 represents the mass part of each additive used with respect to 100 mass parts of cellulose esters.
　なお、実施例２で使用した可塑剤－Ｂ、可塑剤－Ｃ、可塑剤－Ｄ、可塑剤－Ｅ、ＳｕｍｉｌｉｚｅｒＧＡ－８０（住友化学社製）、ＨＰ－１３６（チバ・ジャパン社製）、ＡＤＫ　ＳＴＡＢ　ＰＥＰ－３６（ＡＤＥＫＡ社製）、及びＡＤＫ　ＳＴＡＢ　２１１２（ＡＤＥＫＡ社製）の構造は下記の通りである。 In addition, the plasticizer-B, plasticizer-C, plasticizer-D, plasticizer-E, Sumilizer GA-80 (manufactured by Sumitomo Chemical Co., Ltd.), HP-136 (manufactured by Ciba Japan), ADK used in Example 2 The structures of STAB PEP-36 (manufactured by ADEKA) and ADK STAB 2112 (manufactured by ADEKA) are as follows.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000006
Figure JPOXMLDOC01-appb-C000006
　作製したセルロースエステルフィルム、及び偏光板に対して、実施例１と同様の評価を行った。結果を表４に示す。 Evaluation similar to Example 1 was performed with respect to the produced cellulose ester film and polarizing plate. The results are shown in Table 4.
Figure JPOXMLDOC01-appb-T000007
Figure JPOXMLDOC01-appb-T000007
　以上、表４の結果から、本発明のセルロースエステルフィルムＦ－２５～３６は、比較のセルロースエステルフィルムＦ－３７、３８に対して、リターデーションの発現性に優れ、膜厚ムラが小さく、ヘイズが低く、かつ偏光子との密着性が良好な実用上優れた光学フィルムであることが分かる。 As described above, from the results of Table 4, the cellulose ester films F-25 to 36 of the present invention are more excellent in retardation than the comparative cellulose ester films F-37 and 38, have small film thickness unevenness, and haze. It can be seen that this is a practically excellent optical film having a low adhesion and good adhesion to a polarizer.
　実施例３
　（偏光板の作製）
　実施例１と同様に偏光子を作成し、該偏光子の一方の面に、本発明のセルロースエステルフィルムＦ－１～１２、２５～３６及び比較のセルロースエステルフィルムＦ－１３～２４、３７、３８の実施例１と同様なケン化処理を施したアルカリ処理面を、もう一方の面に、コニカミノルタタックＫＣ４ＵＹ（コニカミノルタオプト（株）製）の同様にアルカリ処理した面を、完全鹸化型ポリビニルアルコール５％水溶液を接着剤として貼合し、保護フィルムが形成された本発明の偏光板Ｑ－１～１２、２５～３６、及び比較の偏光板Ｑ－１３～２４、３７、３８を作製した。 Example 3
(Preparation of polarizing plate)
A polarizer was prepared in the same manner as in Example 1, and on one surface of the polarizer, the cellulose ester films F-1 to 12, 25 to 36 of the present invention and the comparative cellulose ester films F-13 to 24, 37, The surface treated with alkali similar to that of Example 1 in 38, and the other surface treated with the same alkali treated surface of Konica Minolta Tack KC4UY (manufactured by Konica Minolta Opto) was completely saponified. A polarizing plate Q-1 to 12, 25 to 36 of the present invention in which a 5% aqueous solution of polyvinyl alcohol was bonded as an adhesive to form a protective film, and comparative polarizing plates Q-13 to 24, 37, and 38 were produced. did.
　なお、本発明のセルロースエステルフィルムＦ－１～１２、２５～３６、及び比較のセルロースエステルフィルムＦ－１３～２４、３７、３８の幅手方向（遅相軸）と偏光子の透過軸が平行になるように貼り合わせた。 The width direction (slow axis) of the cellulose ester films F-1 to 12, 25 to 36 of the present invention and the comparative cellulose ester films F-13 to 24, 37, and 38 are parallel to the transmission axis of the polarizer. I stuck together.
　（液晶表示装置の作製）
　ＶＡ型液晶表示装置である、シャープ（株）製４２型テレビＬＣ－４２ＲＸ１Ｗの偏光板を剥がし、上記で作製した各々の偏光板を液晶セルのサイズに合わせて断裁した。コニカミノルタタックＫＣ４ＵＹの側を外側にして液晶セルを挟むようにして、前記作製した偏光板２枚を偏光板の偏光軸が元と変わらないように互いに直交するように貼り付け、４２型ＶＡ型カラー液晶表示装置Ｄ－１～１２、２５～３６、及び比較の液晶表示装置Ｄ－１３～２４、３７、３８を作製した。 (Production of liquid crystal display device)
The polarizing plate of the 42-inch television LC-42RX1W manufactured by Sharp Corporation, which is a VA type liquid crystal display device, was peeled off, and each of the polarizing plates produced above was cut according to the size of the liquid crystal cell. A 42-type VA color liquid crystal is bonded to the Konica Minol Tack KC4UY with the liquid crystal cell sandwiched between them so that the two polarizing plates are perpendicular to each other so that the polarization axes of the polarizing plates do not change. Display devices D-1 to 12, 25 to 36, and comparative liquid crystal display devices D-13 to 24, 37, and 38 were produced.
　《液晶表示装置としての特性評価》
　上記のようにして作製した液晶表示装置について、以下に記載した評価を行った。その結果を表５に示す。 《Characteristic evaluation as liquid crystal display device》
The liquid crystal display device produced as described above was evaluated as described below. The results are shown in Table 5.
　（視野角）
　視野角評価は、上記で得られた偏光板を貼合した液晶表示装置を、２３℃５５％ＲＨの環境でＥＬＤＩＭ社製ＥＺ－ｃｏｎｔｒａｓｔ１６０Ｄを用いて測定した。測定方法は、液晶表示装置の白表示と黒表示時のコントラスト比が１０以上を示す表示装置面に対する法線方向からの傾き角の範囲を評価した。法線上を０°とすると傾き角が大きくなるほど視野角領域が広いこととなる。 (Viewing angle)
For viewing angle evaluation, the liquid crystal display device to which the polarizing plate obtained above was bonded was measured using EZ-contrast 160D manufactured by ELDIM in an environment of 23 ° C. and 55% RH. The measuring method evaluated the range of the inclination angle from the normal direction with respect to the display apparatus surface in which the contrast ratio at the time of white display and black display of a liquid crystal display device is 10 or more. If the normal is 0 °, the viewing angle region becomes wider as the tilt angle increases.
　表示装置は水平方向を０°とした時、斜め４５°方位におけるコントラストの値で、下記基準で評価した。 The display device was evaluated according to the following criteria with the contrast value in an oblique 45 ° azimuth when the horizontal direction was 0 °.
　Ａ：表示装置面に対する法線方向からの傾き角が８０°以上である
　Ｂ：表示装置面に対する法線方向からの傾き角が７０°以上８０°未満である
　Ｃ：表示装置面に対する法線方向からの傾き角が７０°に満たない
　（正面コントラストムラ）
　２３℃５５％ＲＨの環境で、各々の液晶表示装置のバックライトを１週間連続点灯した後、測定を行った。測定にはＥＬＤＩＭ社製ＥＺ－Ｃｏｎｔｒａｓｔ１６０Ｄを用いて、液晶表示装置で白表示と黒表示の表示画面の法線方向からの輝度を測定し、その比を正面コントラストとした。 A: The inclination angle from the normal direction to the display device surface is 80 ° or more B: The inclination angle from the normal direction to the display device surface is 70 ° or more and less than 80 ° C: The normal direction to the display device surface The tilt angle from the angle is less than 70 ° (front contrast unevenness)
The measurement was performed after the backlight of each liquid crystal display device was lit continuously for one week in an environment of 23 ° C. and 55% RH. For measurement, EZ-Contrast 160D manufactured by ELDIM was used, the luminance from the normal direction of the display screen of white display and black display was measured with a liquid crystal display device, and the ratio was defined as the front contrast.
　正面コントラスト＝表示装置の法線方向から測定した白表示の輝度／表示装置の法線方向から測定した黒表示の輝度
　液晶表示装置の任意の５点の正面コントラストを測定し、以下の基準にて評価した。 Front contrast = Brightness of white display measured from the normal direction of the display device / Brightness of black display measured from the normal direction of the display device Measure the front contrast of any 5 points on the liquid crystal display device, and use the following criteria evaluated.
　Ａ：正面コントラストが０～５％未満のばらつきであり、ムラが小さい
　Ｂ：正面コントラストが５～１０％未満のばらつきであり、ムラがややある
　Ｃ：正面コントラストが１０％以上のばらつきであり、ムラが大きい
　（視野角劣化）
　２３℃５５％ＲＨの環境でＥＬＤＩＭ社製ＥＺ－Ｃｏｎｔｒａｓｔ１６０Ｄを用いて液晶表示装置の視野角測定を行った。続いて２３℃２０％ＲＨ、更に２３℃８０％ＲＨの環境下で、作製した液晶表示装置の視野角を測定し下記基準にて評価した。最後に２３℃５５％ＲＨの環境でもう一度視野角測定を行い、前記測定の際の変化が可逆変動であることを確認した。尚、これらの測定は、液晶表示装置を当該環境に５時間置いてから測定を行った。 A: Variation with front contrast of 0 to less than 5% and small variation B: Variation with front contrast of less than 5 to 10% and slight variation C: Variation with front contrast of 10% or more, Unevenness (viewing angle degradation)
The viewing angle of the liquid crystal display device was measured using EZ-Contrast 160D manufactured by ELDIM in an environment of 23 ° C. and 55% RH. Subsequently, the viewing angle of the produced liquid crystal display device was measured in an environment of 23 ° C., 20% RH, and further 23 ° C., 80% RH, and evaluated according to the following criteria. Finally, viewing angle measurement was performed again in an environment of 23 ° C. and 55% RH, and it was confirmed that the change during the measurement was a reversible fluctuation. These measurements were made after the liquid crystal display device was placed in the environment for 5 hours.
　Ａ：視野角変動が認められない
　Ｂ：視野角変動がやや認められる
　Ｃ：視野角変動が認められる A: No change in viewing angle B: Some change in viewing angle is observed C: A change in viewing angle is observed
Figure JPOXMLDOC01-appb-T000008
Figure JPOXMLDOC01-appb-T000008
　表５より、本発明の偏光板Ｑ－１～１２、２５～３６を用いた液晶表示装置Ｄ－１～１２、２５～３６は、比較の偏光板Ｑ－１３～２４、３７、３８を用いた液晶表示装置Ｄ－１３～２４、３７、３８に対して視野角が広く、また、正面コントラストムラもなく、湿度が変動する条件下でも視野角変動のない極めて安定な、優れた液晶表示装置であることが分かる。 From Table 5, the liquid crystal display devices D-1 to 12 and 25 to 36 using the polarizing plates Q-1 to 12 and 25 to 36 of the present invention use the comparative polarizing plates Q-13 to 24, 37, and 38, respectively. An excellent liquid crystal display device having a wide viewing angle with respect to the conventional liquid crystal display devices D-13 to 24, 37, and 38, no front contrast unevenness, and extremely stable without changing the viewing angle even under conditions of changing humidity. It turns out that it is.
　１　押出し機
　２　フィルター
　３　スタチックミキサー
　４　流延ダイ
　５　回転支持体（第１冷却ロール）
　６　挟圧回転体（タッチロール）
　７　回転支持体（第２冷却ロール）
　８　回転支持体（第３冷却ロール）
　９　剥離ロール
　１０　光学フィルム
　１１　ダンサーロール
　１２　延伸装置
　１６　巻取り装置
　２１ａ、２１ｂ　保護フィルム
　２２ａ、２２ｂ　位相差フィルム
　２３ａ、２３ｂ　フィルムの遅相軸方向
　２４ａ、２４ｂ　偏光子の透過軸方向
　２５ａ、２５ｂ　偏光子
　２６ａ、２６ｂ　偏光板
　２７　液晶セル
　２９　液晶表示装置
　３１　ダイ本体
　３２　スリット
　４１　金属スリーブ
　４２　弾性ローラ
　４３　金属製の内筒
　４４　ゴム
　４５　冷却水
　５１　外筒
　５２　内筒
　５３　流送空間
　５４　冷却液
　５５ａ、５５ｂ　回転軸
　５６ａ、５６ｂ　外筒支持フランジ
　６０　流体軸筒
　６１ａ、６１ｂ　内筒支持フランジ
　６２ａ、６２ｂ　中間通路 DESCRIPTION OF SYMBOLS 1 Extruder 2 Filter 3 Static mixer 4 Casting die 5 Rotating support body (1st cooling roll)
6 Nipping pressure rotating body (touch roll)
7 Rotating support (second cooling roll)
8 Rotating support (3rd cooling roll)
9 peeling roll 10 optical film 11 dancer roll 12 stretching device 16 winding device 21a, 21b protective film 22a, 22b retardation film 23a, 23b slow axis direction of film 24a, 24b transmission axis direction of polarizer 25a, 25b polarizer 26a, 26b Polarizing plate 27 Liquid crystal cell 29 Liquid crystal display device 31 Die body 32 Slit 41 Metal sleeve 42 Elastic roller 43 Metal inner cylinder 44 Rubber 45 Cooling water 51 Outer cylinder 52 Inner cylinder 53 Flow space 54 Coolant 55a, 55b Rotating shaft 56a, 56b Outer cylinder support flange 60 Fluid shaft cylinder 61a, 61b Inner cylinder support flange 62a, 62b Intermediate passage

Claims (13)

  1. 光学フィルムがセルロースエステルを含有し、該セルロースエステルの１グルコース単位あたりの置換基の種類とその置換度が下記式（１）～（４）の条件を同時に満たすセルロースエステルであることを特徴とする光学フィルム。
    　式（１）　６．３０≦２×Ｘ＋３×Ｙ≦６．８０
    　式（２）　２．３５≦Ｘ＋Ｙ≦２．５５
    　式（３）　０．７０≦Ｘ≦１．１０
    　式（４）　１．４５≦Ｙ≦１．７５
    〔式中、Ｘはアセチル基による置換度を表し、Ｙはプロピオニル基による置換度を表す。〕     The optical film contains a cellulose ester, and the cellulose ester satisfies the conditions of the following formulas (1) to (4) at the same time as the type of substituent and the degree of substitution per glucose unit of the cellulose ester. Optical film.
    Formula (1) 6.30 ≦ 2 × X + 3 × Y ≦ 6.80
    Formula (2) 2.35 ≦ X + Y ≦ 2.55
    Formula (3) 0.70 <= X <= 1.10
    Formula (4) 1.45 ≦ Y ≦ 1.75
    [Wherein, X represents the degree of substitution with an acetyl group, and Y represents the degree of substitution with a propionyl group. ]
  2. 前記セルロースエステルの重量平均分子量（Ｍｗ）が１５万～２５万であることを特徴とする請求項１に記載の光学フィルム。 2. The optical film according to claim 1, wherein the cellulose ester has a weight average molecular weight (Mw) of 150,000 to 250,000.
  3. 多価アルコールエステル系化合物を含むことを特徴とする請求項１または２に記載の光学フィルム。 The optical film according to claim 1, comprising a polyhydric alcohol ester compound.
  4. 炭水化物エステル系化合物を含むことを特徴とする請求項１～３のいずれか１項に記載の光学フィルム。 The optical film according to any one of claims 1 to 3, comprising a carbohydrate ester compound.
  5. ヒンダードフェノール系化合物を含むことを特徴とする請求項１～４のいずれか１項に記載の光学フィルム。 5. The optical film according to claim 1, comprising a hindered phenol compound.
  6. ホスファイト系化合物またはホスホナイト系化合物を含むことを特徴とする請求項１～５のいずれか１項に記載の光学フィルム。 6. The optical film according to claim 1, further comprising a phosphite compound or a phosphonite compound.
  7. 位相差フィルムであることを特徴とする請求項１～６のいずれか１項に記載の光学フィルム。 The optical film according to any one of claims 1 to 6, wherein the optical film is a retardation film.
  8. 請求項１～７のいずれか１項に記載の光学フィルムを溶融流延法によって製造することを特徴とする光学フィルムの製造方法。 An optical film manufacturing method comprising manufacturing the optical film according to any one of claims 1 to 7 by a melt casting method.
  9. 溶融流延の後、得られたフィルムを延伸する工程を含むことを特徴とする請求項８に記載の光学フィルムの製造方法。 The method for producing an optical film according to claim 8, comprising a step of stretching the obtained film after melt casting.
  10. 延伸する工程が二軸方向に延伸する工程であることを特徴とする請求項９に記載の光学フィルムの製造方法。 The method for producing an optical film according to claim 9, wherein the step of stretching is a step of stretching in a biaxial direction.
  11. 請求項１～７のいずれか１項に記載の光学フィルムまたは請求項８～１０のいずれか１項に記載の製造方法により製造された光学フィルムを偏光子の少なくとも一方の面に有することを特徴とする偏光板。 An optical film according to any one of claims 1 to 7 or an optical film produced by the production method according to any one of claims 8 to 10 is provided on at least one surface of a polarizer. A polarizing plate.
  12. 請求項１１に記載の偏光板を液晶セルの少なくとも一方の面に用いることを特徴とする液晶表示装置。 A liquid crystal display device comprising the polarizing plate according to claim 11 on at least one surface of a liquid crystal cell.
  13. 液晶セルがＶＡ型液晶セルであることを特徴とする請求項１２に記載の液晶表示装置。 The liquid crystal display device according to claim 12, wherein the liquid crystal cell is a VA liquid crystal cell.
PCT/JP2009/060048 2008-07-02 2009-06-02 Optical film, manufacturing method for optical film, polarizing plate, and liquid crystal display device using same WO2010001677A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2010518966A JPWO2010001677A1 (en) 2008-07-02 2009-06-02 Optical film, method for producing optical film, polarizing plate and liquid crystal display device using the same

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2008-173203 2008-07-02
JP2008173203 2008-07-02

Publications (1)

Publication Number Publication Date
WO2010001677A1 true WO2010001677A1 (en) 2010-01-07

Family

ID=41465780

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2009/060048 WO2010001677A1 (en) 2008-07-02 2009-06-02 Optical film, manufacturing method for optical film, polarizing plate, and liquid crystal display device using same

Country Status (2)

Country Link
JP (1) JPWO2010001677A1 (en)
WO (1) WO2010001677A1 (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011111484A1 (en) * 2010-03-09 2011-09-15 コニカミノルタオプト株式会社 Method for producing cellulose ester, cellulose ester, and cellulose ester film
WO2012056671A1 (en) * 2010-10-26 2012-05-03 コニカミノルタオプト株式会社 Method for producing cellulose ester-containing resin molded article, optical film, polarizing plate, and display device
WO2014002720A1 (en) * 2012-06-28 2014-01-03 株式会社Adeka Cellulose ester-based resin composition
JP2018515656A (en) * 2015-05-15 2018-06-14 ダウ グローバル テクノロジーズ エルエルシー Process for the production of esterified cellulose ethers with very high molecular weight and low viscosity
JP2022510576A (en) * 2018-11-19 2022-01-27 ヒョスン ケミカル コーポレーション Cellulose ester retardation film

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007145090A1 (en) * 2006-06-13 2007-12-21 Konica Minolta Opto, Inc. Cellulose ester film, process for production of cellulose ester film, polarizing plate, and liquid crystal display device
WO2008026514A1 (en) * 2006-09-01 2008-03-06 Konica Minolta Opto, Inc. Method for producing cellulose acylate film, cellulose acylate film, polarizing plate, and liquid crystal display

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007145090A1 (en) * 2006-06-13 2007-12-21 Konica Minolta Opto, Inc. Cellulose ester film, process for production of cellulose ester film, polarizing plate, and liquid crystal display device
WO2008026514A1 (en) * 2006-09-01 2008-03-06 Konica Minolta Opto, Inc. Method for producing cellulose acylate film, cellulose acylate film, polarizing plate, and liquid crystal display

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011111484A1 (en) * 2010-03-09 2011-09-15 コニカミノルタオプト株式会社 Method for producing cellulose ester, cellulose ester, and cellulose ester film
JPWO2011111484A1 (en) * 2010-03-09 2013-06-27 コニカミノルタ株式会社 Method for producing cellulose ester, cellulose ester, and cellulose ester film
WO2012056671A1 (en) * 2010-10-26 2012-05-03 コニカミノルタオプト株式会社 Method for producing cellulose ester-containing resin molded article, optical film, polarizing plate, and display device
JP5725035B2 (en) * 2010-10-26 2015-05-27 コニカミノルタ株式会社 Method for producing cellulose ester-containing resin molding
WO2014002720A1 (en) * 2012-06-28 2014-01-03 株式会社Adeka Cellulose ester-based resin composition
JPWO2014002720A1 (en) * 2012-06-28 2016-05-30 株式会社Adeka Cellulose ester resin composition
US9580580B2 (en) 2012-06-28 2017-02-28 Adeka Corporation Cellulose ester-based resin composition
JP2018515656A (en) * 2015-05-15 2018-06-14 ダウ グローバル テクノロジーズ エルエルシー Process for the production of esterified cellulose ethers with very high molecular weight and low viscosity
JP2022510576A (en) * 2018-11-19 2022-01-27 ヒョスン ケミカル コーポレーション Cellulose ester retardation film
JP7157248B2 (en) 2018-11-19 2022-10-19 ヒョスン ケミカル コーポレーション Cellulose ester retardation film

Also Published As

Publication number Publication date
JPWO2010001677A1 (en) 2011-12-15

Similar Documents

Publication Publication Date Title
JP5023837B2 (en) Cellulose ester film, method for producing cellulose ester film, polarizing plate using the same, and liquid crystal display device
JP5234103B2 (en) Optical film, method for producing optical film, polarizing plate and liquid crystal display device using the same
JP5212043B2 (en) Optical film manufacturing method, optical film, polarizing plate, and display device
JP4972797B2 (en) Optical film, manufacturing method thereof, polarizing plate, and liquid crystal display device
JP4947050B2 (en) Optical film, method for manufacturing optical film, polarizing plate using the same, and liquid crystal display device
JP2009096955A (en) Optical film, polarizing plate and liquid crystal display device
JP5093227B2 (en) Optical film, optical film manufacturing method, polarizing plate, and liquid crystal display device
WO2010001677A1 (en) Optical film, manufacturing method for optical film, polarizing plate, and liquid crystal display device using same
JP4747985B2 (en) Optical film, polarizing plate and liquid crystal display device using the same
JP2008145739A (en) Optical film, method for manufacturing the same, polarizing plate and liquid crystal display device
JP5182098B2 (en) Optical film, and polarizing plate and liquid crystal display device using the same
JP5146220B2 (en) Optical film, method for producing optical film, polarizing plate, and liquid crystal display device
JP5262182B2 (en) Optical film, manufacturing method thereof, polarizing plate, and liquid crystal display device
JP2010185914A (en) Optical film, method for manufacturing optical film, polarizing plate, and liquid crystal display device
JP4770620B2 (en) Optical film, polarizing plate and liquid crystal display device using the same, and method for producing optical film
JP5012497B2 (en) Optical film, method for manufacturing optical film, polarizing plate using the same, and liquid crystal display device
JP5168022B2 (en) Optical film, optical film manufacturing method, polarizing plate, and liquid crystal display device
JP4952588B2 (en) Optical film, method for manufacturing optical film, polarizing plate using the same, and liquid crystal display device
JP2008143873A (en) Phosphonite compound, method for purifying the same, cellulose ester film using the same, polarizing plate, and liquid crystal display
JP2010117557A (en) Cellulose ester optical film, method of manufacturing the same, polarizing plate, and liquid crystal display
JP4952587B2 (en) Optical film, method for producing optical film, polarizing plate using the same, liquid crystal display device and compound
JP2008224720A (en) Optical film, its manufacturing method, polarizing plate, its manufacturing method, and liquid crystal display device
JP2012247789A (en) Optical film, manufacturing method thereof, polarizer, and liquid crystal display device

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 09773255

Country of ref document: EP

Kind code of ref document: A1

WWE Wipo information: entry into national phase

Ref document number: 2010518966

Country of ref document: JP

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 09773255

Country of ref document: EP

Kind code of ref document: A1