WO2009119122A1 - Polarizer, process for producing polarizer-protecting film, and liquid-crystal display - Google Patents

Polarizer, process for producing polarizer-protecting film, and liquid-crystal display Download PDF

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Publication number
WO2009119122A1
WO2009119122A1 PCT/JP2009/050029 JP2009050029W WO2009119122A1 WO 2009119122 A1 WO2009119122 A1 WO 2009119122A1 JP 2009050029 W JP2009050029 W JP 2009050029W WO 2009119122 A1 WO2009119122 A1 WO 2009119122A1
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Prior art keywords
film
stretching
group
polarizing plate
polarizer
Prior art date
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PCT/JP2009/050029
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French (fr)
Japanese (ja)
Inventor
康志 入江
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コニカミノルタオプト株式会社
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Priority to JP2010505412A priority Critical patent/JP5370354B2/en
Publication of WO2009119122A1 publication Critical patent/WO2009119122A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/023—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets using multilayered plates or sheets
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
    • B29C55/06—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique parallel with the direction of feed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B37/00—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding
    • B32B37/14—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers
    • B32B37/15—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with at least one layer being manufactured and immediately laminated before reaching its stable state, e.g. in which a layer is extruded and laminated while in semi-molten state
    • B32B37/153—Methods or apparatus for laminating, e.g. by curing or by ultrasonic bonding characterised by the properties of the layers with at least one layer being manufactured and immediately laminated before reaching its stable state, e.g. in which a layer is extruded and laminated while in semi-molten state at least one layer is extruded and immediately laminated while in semi-molten state
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2001/00—Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
    • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
    • B29K2995/0018—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds having particular optical properties, e.g. fluorescent or phosphorescent
    • B29K2995/0034—Polarising
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2309/00—Parameters for the laminating or treatment process; Apparatus details
    • B32B2309/02—Temperature
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2309/00—Parameters for the laminating or treatment process; Apparatus details
    • B32B2309/14—Velocity, e.g. feed speeds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00—Electrical equipment
    • B32B2457/20—Displays, e.g. liquid crystal displays, plasma displays
    • B32B2457/202—LCD, i.e. liquid crystal displays
    • 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
    • G02F2201/00—Constructional arrangements not provided for in groups G02F1/00 - G02F7/00
    • G02F2201/50—Protective arrangements

Definitions

  • An object of the present invention relates to a polarizing plate and a liquid crystal display device, and in particular, a polarizing plate that suppresses the occurrence of unevenness of hardness and flatness even in a high temperature and high humidity environment and is excellent in light leakage and unevenness of color, and a liquid crystal having the polarizing plate
  • the present invention relates to a display device.
  • Patent Document 1 focusing on the fact that the problem of light leakage is related to the sound speed of the cellulose ester film, the sound speed is adjusted according to the residual solvent amount and the film drying temperature during solution casting of the cellulose ester film. A technique for suppressing leakage and improving display quality of a liquid crystal display device is proposed.
  • the residual solvent in the final film causes the movement of additives such as UV absorbers, thereby impairing the homogeneity inside the film, resulting in the cellulose ester film. It has been found that when the film is made into a polarizing plate, curling (humidity curling) due to repeated low and high humidity and color unevenness of the liquid crystal display device are induced.
  • Patent Document 2 a melt casting film forming method is known as a method for reducing residual solvent
  • Patent Document 3 discloses a technique for improving humidity curl of a cellulose ester film using this method. Has been.
  • Patent Document 3 describes that the elastic modulus is required to be 1.5 to 2.95 kN / m 2 .
  • An object of the present invention is to provide a polarizing plate that suppresses the occurrence of unevenness in hardness and flatness in a high-temperature and high-humidity environment, and is excellent in light leakage and color unevenness, and a liquid crystal display device having this polarizing plate.
  • the polarizing plate protective film 1 satisfies the following formulas (A1) and (A2) at the same time, and contains a solvent
  • the polarizing plate protective film 2 is a cellulose ester film having an amount of 0.01% by mass or less and a sound velocity of at least one of a film forming direction and a width direction at 100 ° C. of 1.6 to 2.2 km / s. Is an optically anisotropic film having a variation in retardation Rt in the thickness direction of 10 nm or less.
  • Formula (A1) 2.0 ⁇ X + Y ⁇ 3.0
  • Formula (A2) 1.0 ⁇ Y ⁇ 2.5
  • X represents the degree of substitution of the acetyl group of the cellulose ester
  • Y represents the degree of substitution of the propionyl group or butyryl group.
  • 2. The polarizing plate according to 1 above, wherein the speed of sound has a relationship of 0.9 ⁇ sound speed (TD) / sound speed (MD) ⁇ 1.1. (MD represents the film forming direction and TD represents the width direction) 3.
  • This polarizing plate protective film is formed into a film by melt film-forming, and it is the following formula (B) in the film-forming direction of a film 3.
  • a liquid crystal display device comprising the polarizing plate according to 1 or 2 above.
  • the polarizing plate of the present invention has the effect of suppressing the occurrence of unevenness of hardness and flatness in a high temperature and high humidity environment and is excellent in light leakage and color unevenness.
  • a polarizing plate comprising a polarizer and two polarizing plate protective films 1 and 2 sandwiching the polarizer
  • the polarizing plate protective film 1 has the following formulas (A1) and (A2): And a cellulose ester film having a solvent content of 0.01% by mass or less and a sound velocity of at least one of the film forming direction and the width direction at 100 ° C. of 1.6 to 2.2 km / s
  • the polarizing plate protective film 2 is an optically anisotropic film having a variation in retardation Rt in the thickness direction of 10 nm or less.
  • the polarizing plate protective film 1 of the present invention is characterized in that it is a cellulose ester film having a sound velocity of at least one of the film forming direction and the width direction at 100 ° C. of 1.6 to 2.2 km / s. is there.
  • the cellulose ester film having such a sound speed can be obtained by melt casting a composition containing a cellulose ester that satisfies the above formulas (A1) and (A2) and an additive at the same time.
  • the composition is heated and melted to a temperature exhibiting fluidity to form a melt, and after casting and cooling the melt, at least the film forming direction is represented by the following formula (1).
  • the film is stretched at a stretching speed of 1000% / min to 30000% / min, and preferably further stretched in the width direction at a stretching speed of 400% / min to 1500% / min.
  • a cellulose ester film having a sound velocity of either 1.6 to 2.2 km / s can be obtained.
  • Stretching speed (% / min) ⁇ (dimension after stretching / dimension before stretching) -1 ⁇ ⁇ 100 (%) / time required for stretching (min)
  • the present invention achieves the sound velocity of the cellulose ester film by realizing a stretching speed in a range in which the film was broken by the solution casting film forming method and could not be used by the melt casting film forming method. It has been found that a cellulose ester film having an excellent color unevenness and light leakage can be obtained by adjusting to a range of 6 to 2.2 km / s.
  • the inventor has inferred the mechanism for obtaining a cellulose ester film having a desired sound speed by adjusting the stretching speed as follows.
  • the sound velocity has the following relationship in the film forming direction (MD) and the width direction (TD).
  • the present inventor has found that the hardness unevenness and flatness deterioration under high temperature and high humidity depend very strongly on the substituent of the cellulose ester in the case of a film substantially free of the contained solvent.
  • the protective film is non-uniformly plastically deformed in the screen, resulting in uneven hardness and flatness.
  • the residual solvent amount after film-forming and drying (the amount of solvent that is finally contained in the film) is calculated for the entire cellulose ester film. It can be 0.01 mass%.
  • the contained solvent is an organic solvent having a boiling point of 120 ° C. or lower used in casting film formation, and is a solvent remaining in the film even after film formation.
  • the cellulose ester film of the present invention comprises a cellulose ester and an additive.
  • ⁇ Cellulose ester ⁇ The cellulose ester used in the present invention is a carboxylic acid ester having about 2 to 22 carbon atoms, may be an aromatic carboxylic acid ester, and is particularly preferably a lower fatty acid ester of cellulose.
  • the lower fatty acid in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms.
  • the acyl group bonded to the hydroxyl group may be linear or branched or may form a ring. Furthermore, another substituent may be substituted.
  • the carbon number is preferably selected from acyl groups having 2 to 6 carbon atoms.
  • the cellulose ester of the present invention is required to satisfy the above (A1) and (A2) at the same time.
  • Y is a propionyl group, preferably 1.1 ⁇ Y ⁇ 2.0. 1 ⁇ Y ⁇ 1.5 is particularly preferable for light leakage.
  • substitution degree range in the present invention can increase the stretching speed, and the sound speed can also achieve the range of the present invention.
  • the method for measuring the substitution degree of the acyl group can be measured according to ASTM-D817-96.
  • the molecular weight of cellulose ester is preferably 60000-300000, more preferably 70000-200000 in terms of number average molecular weight (Mn).
  • the cellulose ester further used preferably has a weight average molecular weight (Mw) / number average molecular weight (Mn) ratio of 4.0 or less, more preferably 1.4 to 2.3.
  • the average molecular weight and molecular weight distribution of cellulose ester can be measured using gel permeation chromatography (GPC), the number average molecular weight (Mn) and the weight average molecular weight (Mw) are calculated using this, and the ratio is calculated. be able to.
  • GPC gel permeation chromatography
  • the measurement conditions are as follows.
  • the residual sulfuric acid content in the cellulose ester of 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. When the residual sulfuric acid content exceeds 45 ppm, there is a tendency that deposits on the die lip portion during heat melting increase.
  • the residual sulfuric acid content can be measured by the method prescribed in ASTM D817-96.
  • the free acid content in the cellulose ester of the present invention is preferably 1 to 500 ppm. Within the above range, there is no increase in deposits on the die lip and it is difficult to break.
  • the present invention is preferably in the range of 1 to 100 ppm, and it is 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 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 if it is a poor solvent. Low molecular organic impurities can be removed.
  • a poor solvent such as methanol or ethanol
  • the cellulose ester of this invention has few bright spot foreign materials when it is made into a film.
  • the bright spot foreign matter preferably has a bright spot diameter of 0.01 mm or more and 200 pieces / cm 2 or less, more preferably 100 pieces / cm 2 or less, and preferably 50 pieces / cm 2 or less. 30 / cm 2 or less, preferably 10 / cm 2 or less, and 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.
  • the number is preferably 30 pieces / cm 2 or less, more preferably 10 pieces / cm 2 or less, and most preferably none.
  • the cellulose ester film in the present invention includes a plasticizer that imparts processability to the film, an antioxidant that prevents deterioration of the film, an ultraviolet absorber that imparts an ultraviolet absorbing function, and fine particles that impart slipperiness to the film (matting agent). ), Additives such as a retardation adjusting agent for adjusting the retardation of the film may be contained.
  • the film forming material contains at least one plasticizer.
  • plasticizers can be used alone or in combination of two or more, but at least one plasticizer has a structure in which an organic acid and a trihydric or higher alcohol are condensed and has a molecular weight of 350 to 1500. It is preferable that it is an agent.
  • plasticizers that can be used are not particularly limited, but are preferably polycarboxylic acid ester plasticizers, glycolate plasticizers, phthalate ester plasticizers, fatty acid ester plasticizers, polymer plasticizers. Selected from sugar ester plasticizers and the like.
  • the amount of the plasticizer used is less than 1% by mass relative to the cellulose derivative, the effect of reducing the moisture permeability of the film is small, which is not preferable. If the amount exceeds 20% by mass, the physical properties of the film at high temperature durability deteriorate. ⁇ 20% by weight is preferred.
  • the polyhydric alcohol ester plasticizer of the present invention is an ester of an organic acid and a polyhydric alcohol, and the organic acid is represented by the following general formula (1).
  • R 1 to R 5 represent a hydrogen atom or a cycloalkyl group, an aralkyl group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an aralkyloxy group, an acyl group, a carbonyloxy group, an oxycarbonyl group, or an oxycarbonyloxy group. These may be further substituted.
  • L represents a linking group and represents a substituted or unsubstituted alkylene group, an oxygen atom, or a direct bond.
  • the cycloalkyl group represented by R 1 to R 5 is preferably a cycloalkyl group having 3 to 8 carbon atoms, specifically, a group such as cyclopropyl, cyclopentyl, or cyclohexyl. These groups may be substituted, and preferred substituents include halogen atoms such as chlorine atom, bromine atom, fluorine atom, hydroxyl group, alkyl group, alkoxy group, cycloalkoxy group, aralkyl group (this phenyl group).
  • the group may be further substituted with an alkyl group or a halogen atom), an alkenyl group such as a vinyl group or an allyl group, or a phenyl group (this phenyl group may be further substituted with an alkyl group or a halogen atom).
  • Phenoxy group this phenyl group may be further substituted with an alkyl group or a halogen atom
  • acyl groups having 2 to 8 carbon atoms such as acetyl group and propionyl group, acetyloxy group, propionyloxy And an unsubstituted carbonyloxy group having 2 to 8 carbon atoms, such as a group.
  • the aralkyl group represented by R 1 to R 5 represents a benzyl group, a phenethyl group, a ⁇ -phenylpropyl group, or the like. These groups may be substituted, and preferred substituents include The group which may be substituted with the said cycloalkyl group can be mentioned similarly.
  • Examples of the alkoxy group represented by R 1 to R 5 include an alkoxy group having 1 to 8 carbon atoms, and specifically include methoxy, ethoxy, n-propoxy, n-butoxy, n-octyloxy, isopropoxy , Alkoxy groups such as isobutoxy, 2-ethylhexyloxy, or t-butoxy.
  • halogen atoms such as chlorine atom, bromine atom, fluorine atom, hydroxyl group, alkoxy group, cycloalkoxy group, aralkyl group (this phenyl group). May be substituted with an alkyl group or a halogen atom), an alkenyl group, a phenyl group (this phenyl group may be further substituted with an alkyl group or a halogen atom), an aryloxy group (for example, phenoxy)
  • An acyl group such as an acetyl group or a propionyl group, or an aryl group such as an acetyloxy group or a propionyloxy group.
  • An unsubstituted acyloxy group or an arylcarbonyl such as a benzoyloxy group Alkoxy group.
  • Examples of the cycloalkoxy group represented by R 1 to R 5 include an unsubstituted cycloalkoxy group having 1 to 8 carbon atoms, specifically cyclopropyloxy, cyclopentyloxy, cyclohexyloxy. And the like.
  • these groups may be substituted, and preferred examples of the substituent include the same groups that may be substituted with the cycloalkyl group.
  • Examples of the aryloxy group represented by R 1 to R 5 include a phenoxy group, and the phenyl group includes a substituent that may be substituted with the cycloalkyl group such as an alkyl group or a halogen atom. May be substituted.
  • Examples of the aralkyloxy group represented by R 1 to R 5 include a benzyloxy group, a phenethyloxy group, and the like. These substituents may be further substituted. Preferred substituents include the cycloalkyl group described above. The group which may be substituted with a group can be mentioned similarly.
  • Examples of the acyl group represented by R 1 to R 5 include an unsubstituted acyl group having 2 to 8 carbon atoms such as an acetyl group and a propionyl group (the hydrocarbon group of the acyl group includes alkyl, alkenyl, alkynyl). These substituents may be further substituted, and preferred substituents include the same groups that may be substituted with the cycloalkyl group.
  • the carbonyloxy group represented by R 1 to R 5 is an unsubstituted acyloxy group having 2 to 8 carbon atoms such as acetyloxy group and propionyloxy group (the hydrocarbon group of the acyl group is alkyl, alkenyl, alkynyl). And arylcarbonyloxy groups such as a benzoyloxy group, and these groups may be further substituted with the same groups as those which may be substituted with the cycloalkyl group.
  • the oxycarbonyl group represented by R 1 to R 5 represents an alkoxycarbonyl group such as a methoxycarbonyl group, an ethoxycarbonyl group or a propyloxycarbonyl group, or an aryloxycarbonyl group such as a phenoxycarbonyl group.
  • substituents may be further substituted, and preferable substituents include the same groups that may be substituted with the cycloalkyl group.
  • the oxycarbonyloxy group represented by R 1 to R 5 represents an alkoxycarbonyloxy group having 1 to 8 carbon atoms such as a methoxycarbonyloxy group, and these substituents may be further substituted and are preferably substituted. Examples of the group include the same groups that may be substituted on the cycloalkyl group.
  • R 1 to R 5 may be connected to each other to form a ring structure.
  • the linking group represented by L represents a substituted or unsubstituted alkylene group, an oxygen atom, or a direct bond, and the alkylene group is a group such as a methylene group, an ethylene group, or a propylene group. This group may be further substituted with the above-mentioned groups which may be substituted with the groups represented by R 1 to R 5 .
  • a direct bond and an aromatic carboxylic acid are particularly preferable as the linking group represented by L.
  • the organic acid represented by the general formula (1) constituting the ester compound serving as a plasticizer in the present invention includes at least R 1 or R 2 having the alkoxy group, acyl group, oxycarbonyl group, carbonyl group. Those having an oxy group or an oxycarbonyloxy group are preferred. A compound having a plurality of substituents is also preferred.
  • the organic acid substituting the hydroxyl group of the trivalent or higher alcohol may be a single type or a plurality of types.
  • the trihydric or higher alcohol compound that reacts with the organic acid represented by the general formula (1) to form a polyhydric alcohol ester compound is preferably a trihydric to polyhydric aliphatic polyhydric alcohol.
  • the trihydric or higher alcohol is preferably represented by the following general formula (2).
  • R ′-(OH) m R ′-(OH) m
  • R ′ represents an m-valent organic group
  • m represents a positive integer of 3 or more
  • the OH group represents an alcoholic hydroxyl group.
  • Particularly preferred is a polyhydric alcohol having 3 or 4 as m.
  • Examples of preferred polyhydric alcohols include the following, but the present invention is not limited to these.
  • glycerin trimethylolethane, trimethylolpropane and pentaerythritol are preferable.
  • An organic acid represented by the general formula (1) and an ester of a trihydric or higher polyhydric alcohol represented by the general formula (2) can be synthesized by a known method. In the examples, typical synthesis examples are shown.
  • the organic acid represented by the general formula (1) and the polyhydric alcohol represented by the general formula (2) are condensed and esterified in the presence of an acid, for example.
  • a plasticizer comprising an organic acid represented by the general formula (1) and an ester of a trihydric or higher polyhydric alcohol represented by the general formula (2)
  • a compound represented by the following general formula (3) is preferable. .
  • R 6 to R 20 represent a hydrogen atom or a cycloalkyl group, an aralkyl group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an aralkyloxy group, an acyl group, a carbonyloxy group, an oxycarbonyl group, or an oxycarbonyloxy group. These may be further substituted.
  • R 21 represents a hydrogen atom or an alkyl group.
  • the cycloalkyl group, aralkyl group, alkoxy group, cycloalkoxy group, aryloxy group, aralkyloxy group, acyl group, carbonyloxy group, oxycarbonyl group, and oxycarbonyloxy group of R 6 to R 20 are represented by the above general formula ( Examples thereof include the same groups as R 1 to R 5 in 1).
  • sugar ester plasticizer obtained by esterifying a hydroxyl group of a sugar compound in which 1 to 12 at least one structure selected from a furanose structure and a pyranose structure is bonded.
  • sugar ester compound used in the present invention examples include glucose, galactose, mannose, fructose, xylose, arabinose, lactose, sucrose, cellobiose, cellotriose, maltotriose, raffinose, etc., particularly both furanose structure and pyranose structure. What has is preferable.
  • An example is sucrose.
  • the sugar ester plasticizer used in the present invention is one in which part or all of the hydroxyl groups of the sugar compound are esterified or a mixture thereof.
  • Examples of commercially available products include Monopet SB (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).
  • the cellulose ester film of the present invention preferably uses a polymer plasticizer.
  • acrylic polymers are particularly preferred.
  • aliphatic hydrocarbon polymers such as polyvinyl isobutyl ether and poly N-vinyl pyrrolidone, copolymers of methyl methacrylate and N-vinyl pyrrolidone (for example, a copolymerization ratio of any ratio between 1:99 and 99: 1), a styrene polymer such as polystyrene and poly-4-hydroxystyrene, a copolymer of methyl methacrylate and 4-hydroxystyrene (eg, copolymerization) Any ratio between 1:99 and 99: 1), polybutylene succinate, polyethylene
  • the number average molecular weight is preferably about 1,000 to 500,000, particularly preferably 5000 to 200,000. If it is 1,000 or less, the volatility becomes large, and if it exceeds 500,000, the plasticizing ability tends to decrease, which may adversely affect the mechanical properties of the cellulose ester optical film.
  • These polymer plasticizers may be homopolymers composed of repeating units of one kind of monomer or copolymers having a repeating structure of a plurality of monomers. Two or more of the above polymers may be used in combination.
  • the method for measuring the amount of plasticizer on the surface is not particularly limited.
  • a knife or the like is used to quantitatively analyze the surface of the film by cutting it about 20 nm or the amount of plasticizer in the thickness direction of the film is measured by IR or atomic absorption. It is quantified using a method such as scanning with the above.
  • Antioxidant> In this invention, what is generally known can be used as an antioxidant.
  • lactone, sulfur, phenol, double bond, hindered amine and phosphorus compounds can be preferably used.
  • the phenolic compound preferably has a 2,6-dialkylphenol structure.
  • trade names of Ciba Japan Co., Ltd. “Irganox 1076”, “Irganox 1010”, and ADEKA “ADEKA STAB AO-50” And those commercially available.
  • the phosphorus compounds are, for example, from Sumitomo Chemical Co., Ltd., “Sumilizer GP” (AO2), from ADEKA Co., Ltd., “ADK STAB PEP-24G”, “ADK STAB PEP-36” (AO1) and “ADK STAB 3010”, Those commercially available under the trade name “IRGAFOS P-EPQ” (AO4) from Ciba Japan Co., Ltd. and “GSY-P101” (AO3) from Sakai Chemical Industry Co., Ltd. are preferred.
  • the above-mentioned hindered amine compounds are preferably commercially available from Ciba Japan Co., Ltd. under the trade names of “Tinuvin 144 (AO2)” and “Tinvin 770”, and from ADEKA Co., Ltd. as “ADK STAB LA-52”.
  • the above sulfur compounds are preferably those commercially available from Sumitomo Chemical Co., Ltd. under the trade names “Sumilizer TPL-R” and “Sumilizer TP-D”.
  • the above-mentioned double bond type compounds are preferably those commercially available from Sumitomo Chemical Co., Ltd. under the trade names “Sumilizer GM” (AO5) and “Sumilizer GS” (AO3).
  • the amount of these antioxidants and the like to be added is appropriately determined in accordance with the process for recycling and use, but generally 0.05 to 20% by mass, preferably with respect to the resin as the main raw material of the film Is added in the range of 0.1 to 1% by mass.
  • the cellulose ester film of the present invention may contain a compound for adjusting the retardation.
  • an aromatic compound having two or more aromatic rings as described in the specification of European Patent No. 911,656A2 can also be used.
  • the aromatic ring of the aromatic compound includes an aromatic heterocyclic ring in addition to the aromatic hydrocarbon ring.
  • An aromatic heterocyclic ring is particularly preferred, and the aromatic heterocyclic ring is generally an unsaturated heterocyclic ring. Of these, compounds having a 1,3,5-triazine ring are particularly preferred.
  • a colorant means a dye or a pigment. In the present invention, the colorant means an effect of making the color tone of a liquid crystal screen blue, adjusting the yellow index, and reducing haze.
  • Various dyes and pigments can be used as the colorant, but anthraquinone dyes, azo dyes, phthalocyanine pigments and the like are effective.
  • ⁇ Ultraviolet absorber> Although the ultraviolet absorber used in the present invention is not particularly limited, for example, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, nickel complex compounds, inorganic powders Examples include the body. It is good also as a polymer type ultraviolet absorber.
  • ⁇ Matting agent> In the present invention, it is preferable to add a matting agent in order to impart film slipperiness.
  • any inorganic compound or organic compound may be used as long as it has heat resistance at the time of melting without impairing the transparency of the obtained film.
  • talc mica, zeolite, diatomaceous earth, Calcined siliceous clay, kaolin, sericite, bentonite, smectite, clay, silica, quartz powder, glass beads, glass powder, glass flakes, milled fiber, wollastonite, boron nitride, boron carbide, titanium boride, magnesium carbonate, Heavy calcium carbonate, light calcium carbonate, calcium silicate, aluminum silicate, magnesium silicate, magnesium aluminosilicate, alumina, silica, zinc oxide, titanium dioxide, iron oxide, magnesium oxide, zirconium oxide, aluminum hydroxide, calcium hydroxide, water Magne oxide Um, calcium sulfate, barium sulfate, silicon carbide, aluminum carbide, titanium carbide, aluminum nitride
  • matting agents can be used alone or in combination of two or more.
  • particles having different particle sizes and shapes for example, acicular and spherical
  • both transparency and slipperiness can be made highly compatible.
  • silicon dioxide is particularly preferably used since it has a refractive index close to that of cellulose ester and is excellent in transparency (haze).
  • Specific examples of silicon dioxide include Aerosil 200V, Aerosil R972V, Aerosil R972, R974, R812, 200, 300, R202, OX50, TT600 (above Nippon Aerosil Co., Ltd.), Seahoster KEP-10, Seahoster KEP-30, Commercial products with trade names such as Seahoster KEP-50 (above, Nippon Shokubai Co., Ltd.), Silo Hovic 100 (Fuji Silysia), Nip Seal E220A (Nihon Silica Kogyo), Admafine SO (Admatechs), etc. Can be preferably used.
  • the shape of the particles can be used without particular limitation, such as indefinite shape, needle shape, flat shape, spherical shape, etc.
  • the use of spherical particles is preferable because the transparency of the resulting film can be improved.
  • the particle size is preferably smaller than the wavelength of visible light, and more preferably 1 ⁇ 2 or less of the wavelength of visible light. .
  • the slipperiness may not be improved, so the range of 80 nm to 180 nm is particularly preferable.
  • the particle size means the size of the aggregate when the particle is an aggregate of primary particles. Moreover, when a particle is not spherical, it means the diameter of a circle corresponding to the projected area.
  • a hydrogen bonding solvent can be added for the purpose of reducing the melt viscosity.
  • the hydrogen bonding solvent is J.I. N.
  • the glass transition temperature of the cellulose resin used alone is higher than that.
  • the melting temperature of the cellulose resin composition can be lowered by adding a hydrogen bonding solvent.
  • melt viscosity of the cellulose resin composition containing a hydrogen bonding solvent can be lowered than that of the cellulose resin at the same melting temperature.
  • Examples of the hydrogen bonding solvent include alcohols such as methanol, ethanol, propanol, isopropanol, n-butanol, sec-butanol, t-butanol, 2-ethylhexanol, heptanol, octanol, nonanol, dodecanol, ethylene glycol, Propylene glycol, hexylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, hexyl cellosolve, glycerin, etc., ketones: acetone, methyl ethyl ketone, etc., carboxylic acids: eg formic acid, acetic acid, propionic acid, Butyric acid, etc., ethers: eg, diethyl ether, tetrahydrofuran, dioxane,
  • These hydrogen bonding solvents can be used alone or in admixture of two or more.
  • alcohol, ketone, and ether are preferable, and methanol, ethanol, propanol, isopropanol, octanol, dodecanol, ethylene glycol, glycerin, acetone, and tetrahydrofuran are particularly preferable.
  • water-soluble solvents such as methanol, ethanol, propanol, isopropanol, ethylene glycol, glycerin, acetone, and tetrahydrofuran are particularly preferable.
  • water-soluble means that the solubility in 100 g of water is 10 g or more.
  • the melt casting film formation in the present invention is a method in which a composition containing additives such as cellulose ester and a plasticizer is heated and melted to a temperature showing fluidity, and then a melt containing fluid cellulose ester is cast. This is defined as melt film formation.
  • the heat melting molding method 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.
  • the film forming method will be described.
  • Pelletization may be performed by a known method. For example, dry cellulose ester, plasticizer, and other additives are fed to an extruder using a feeder and kneaded using a single-screw or twin-screw extruder, and then formed into a strand from a die. It can be done by extrusion, water cooling or air cooling and cutting.
  • cellulose ester easily absorbs moisture, it is preferable to dry it at 70 to 140 ° C. for 3 hours or more with a dehumidifying hot air dryer or a vacuum dryer so that the moisture content is 200 ppm or less, and further 100 ppm or less.
  • Additives may be mixed before being supplied to the extruder, or may be supplied by individual feeders. A small amount of additives such as antioxidants are preferably mixed in advance in order to mix more uniformly.
  • Mixing of the antioxidants may be performed by mixing solids, and if necessary, the antioxidant may be dissolved in a solvent, impregnated with cellulose ester and mixed, or sprayed and mixed. Also good.
  • a vacuum nauter mixer or the like is preferable because drying and mixing can be performed simultaneously. Further, if the contact with air, such as the exit from the feeder unit or die, it is preferable that the atmosphere such as dehumidified air and dehumidified N 2 gas.
  • Matting agents, UV absorbers, and the like may be applied to the obtained pellets or added in an extruder during film formation.
  • the extruder is preferably processed at as low a temperature as possible so as to be able to be pelletized so that the shear force is suppressed and the resin does not deteriorate (molecular weight reduction, coloring, gel formation, etc.).
  • a twin screw extruder it is preferable to rotate in the same direction using a deep groove type screw. From the uniformity of kneading, the meshing type is preferable.
  • ⁇ Kneader discs can improve kneadability, but care must be taken against shearing heat generation. Mixability is sufficient without using a kneader disk.
  • the suction from the vent hole may be performed as necessary. Since there is almost no volatile component at low temperatures, there may be no vent hole.
  • the b * value as an index of yellowness is preferably in the range of -5 to 10, more preferably in the range of -1 to 8, and preferably in the range of -1 to 5. More preferred.
  • B * value can be measured with a spectrophotometer CM-3700d (manufactured by Konica Minolta Sensing Co., Ltd.) with a light source of D65 (color temperature 6504K) and a viewing angle of 10 °.
  • Film formation is performed using the pellets obtained as described above.
  • the raw material powder can be directly fed to the extruder by a feeder without being pelletized to form a film as it is.
  • the extrusion flow rate is preferably performed stably by introducing a gear pump. Further, a stainless fiber sintered filter is preferably used as a filter used for removing foreign substances.
  • the stainless steel fiber sintered filter is a united stainless steel fiber body that is intricately intertwined and compressed, and the contact points are sintered and integrated.
  • the density of the fiber is changed depending on the thickness of the fiber and the amount of compression, and the filtration accuracy is improved. Can be adjusted.
  • a multilayer body in which the filtration accuracy is repeated coarsely and densely multiple times. Further, it is preferable to adopt a configuration in which the filtration accuracy is sequentially increased or a method in which coarse and dense filtration accuracy is repeated, so that the filtration life of the filter can be extended and the accuracy of capturing foreign matters and gels can be improved.
  • the piping from the extruder to the die has a structure in which the resin retention portion is minimized. It is preferable to use a die that has as few scratches as possible inside the lip.
  • the inner surface that comes into contact with the molten resin is preferably subjected to surface treatment that makes it difficult for the molten resin to adhere to the surface by reducing the surface roughness or using a material with low surface energy.
  • a hard chrome plated or ceramic sprayed material is polished so that the surface roughness is 0.2 S or less.
  • Additives such as plasticizers may be mixed with the resin in advance or 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 film temperature on the touch roll side when the film is nipped between the cooling roll and the elastic touch roll is preferably Tg or more and Tg + 110 ° C. or less of the film.
  • a well-known roll can be used for the roll which has the elastic body surface used for such a purpose.
  • the film obtained as described above passes through the step of contacting the cooling roll, and then the film is stretched at a stretching speed represented by the following formula (1) in the film forming direction of 1000% / min to 30000% / Stretching at min is a preferable method for controlling the sound speed of the film to a desired sound speed.
  • the time required for stretching was calculated from the distance of the stretching process and the film conveyance speed, and the dimension after stretching was obtained by marking the length after stretching with a mark determined before stretching.
  • Stretching speed (% / min) ⁇ (dimension after stretching / dimension before stretching) -1 ⁇ ⁇ 100 (%) / time required for stretching (min) Further, the film is stretched in the width direction of the film at a stretching speed represented by the formula (1) of 400% / min to 1500% / min, and the film is at least one of the film forming direction and the width direction. It is preferable to stretch 50% to 200%.
  • the draw ratio is too small, it is difficult to obtain a cellulose ester film having a preferable sound velocity value.
  • the stretch ratio is too large, the film may be broken or the film may not be able to withstand its own weight, and the film will sag.
  • a known roll stretching machine or tenter can be preferably used.
  • the stretching temperature is preferably performed in the temperature range of Tg to Tg + 60 ° C. of the resin constituting the film.
  • the glass transition temperature Tg of the film constituting material can be controlled by making the material type constituting the film and the ratio of the constituting material different.
  • Tg is 110 ° C. or higher, preferably 125 ° 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 lower.
  • 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 stretching temperature is too low, it may break, and if it is too high, the desired retardation may not be obtained.
  • the stretching is preferably performed under a uniform temperature distribution controlled in the width direction.
  • the temperature is preferably within ⁇ 2 ° C, more preferably within ⁇ 1 ° C, and particularly preferably within ⁇ 0.5 ° C.
  • the end Before winding, the end may be slit and trimmed to the product width, and knurled (embossed) may be applied to both ends to prevent sticking and scratching during winding.
  • the knurling method can process a metal ring having an uneven pattern on its side surface by heating or pressing.
  • Stretching is performed by stretching in the film forming direction (MD) (longitudinal stretching), stretching in the width direction (TD) (transverse stretching), and combinations thereof.
  • Longitudinal stretching includes roll stretching (stretching in the film forming direction using two or more pairs of nip rolls with increased peripheral speed on the outlet side) and fixed end stretching (gripping both ends of the film and transporting it gradually in the film forming direction. For example, stretching in the film forming direction).
  • the transverse stretching can be performed by tenter stretching (holding both ends of the film with a chuck and stretching the film in the transverse direction (perpendicular to the film forming direction)) or the like.
  • the draw ratio is at least 1% to 250%, more preferably 2% to 200%, and still more preferably 3% to 150%. Although it may be stretched evenly in the vertical and horizontal directions, it is more preferable to stretch one of the stretch ratios more than the other and stretch the same.
  • Either longitudinal (MD) or lateral (TD) may be increased, but the smaller draw ratio is preferably 0% to 30%, more preferably 0% to 25%, and still more preferably 0% to 20%. %.
  • the larger draw ratio is 1% to 250%, more preferably 10% to 200%, and still more preferably 30% to 150%.
  • Stretch ratio (%) 100 ⁇ ⁇ (Length after stretching) ⁇ (Length before stretching) ⁇ / (Length before stretching)
  • These longitudinal stretching and lateral stretching may be performed independently (uniaxial stretching) or may be performed in combination (biaxial stretching). In the case of biaxial stretching, it may be carried out in the longitudinal and transverse sequential manners (sequential stretching) or simultaneously (simultaneous stretching).
  • the stretching speed of stretching in the film forming direction is preferably 1000% / min to 30000% / min, more preferably 5000% / min to 20000% / min, and further preferably 10,000% / min to 20000% / min.
  • the stretching speed refers to the average value of the stretching speed of each stage.
  • the film is stretched in the width direction of the film at a stretching speed of 400% / min to 1500% / min. More preferably, it is 500% / min to 1400% / min, and further preferably 600% / min to 1300% / min.
  • Ro indicates in-plane retardation
  • the difference between the refractive index in the in-plane film forming direction MD and the refractive index in the width direction TD is multiplied by the thickness
  • Rt indicates the thickness direction retardation.
  • the difference between the in-plane refractive index (average of the film forming direction MD and the width direction TD) and the refractive index in the thickness direction is multiplied by the thickness.
  • Stretching can be performed sequentially or simultaneously with respect to, for example, the film forming direction and the width direction of the film. 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 film breakage may occur.
  • Stretching in biaxial directions perpendicular to each other is an effective method for putting the refractive indexes nx, ny, and nz of the film within a predetermined range.
  • nx is the refractive index in the film MD direction
  • ny is the refractive index in the TD direction
  • nz is the refractive index in the thickness direction.
  • the width shrinkage of the film can be suppressed or improved by 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, and by stretching the film in the width direction, a shrinkage force is generated in the center of the film, and the phenomenon is caused by the end being fixed, It is thought to be a so-called Boeing phenomenon.
  • the film thickness fluctuation of the obtained film can be reduced by stretching in biaxial directions perpendicular to each other. If the film thickness variation is too large, the phase difference becomes uneven, and unevenness such as coloring may be a problem when used in a liquid crystal display.
  • the film thickness variation of the cellulose ester film of the present invention is preferably in the range of ⁇ 3%, more preferably ⁇ 1%.
  • the film After stretching, after slitting the end of the film to a product width with a slitter, the film is subjected to knurling (embossing) on both ends of the film by a knurling device consisting of an embossing ring and a back roll, and a winder By taking up with, it prevents the cellulose ester film (original winding) from sticking and the generation of scratches.
  • knurling embossing
  • the knurling method can process a metal ring having an uneven pattern on its side surface by heating or pressing.
  • the melt-extrusion tends to increase the residence time on the side of the end due to the shape of the casting die, thereby promoting the coloring of the end of the film.
  • the yellow index Ye at the end in the width direction of the film immediately after melt extrusion and the yellow index Yc at the center of the film preferably satisfy the following formula, and more preferably, Ye / Yc is 3.0 or less.
  • the yellow index at the end is defined as the maximum value within 30 mm from both ends in the width direction of the film.
  • the thickness of the film is preferably 10 to 500 ⁇ m.
  • the lower limit is 20 ⁇ m or more, preferably 30 ⁇ m or more.
  • the upper limit is 150 ⁇ m or less, preferably 120 ⁇ m or less.
  • a particularly preferred range is 25 to 90 ⁇ m.
  • the film is thick, the polarizing plate after polarizing plate processing becomes too thick, so that it is not suitable for the purpose of thin and light in liquid crystal displays used for notebook computers and mobile electronic devices.
  • the film is thin, the moisture permeability of the film increases, and the ability to protect the polarizer from humidity tends to be reduced.
  • a transparent conductive layer In producing the cellulose ester film of the present invention, before and / or after stretching, a transparent conductive layer, a hard coat layer, an antireflection layer, a slippery layer, an easy adhesion layer, an antiglare layer, a barrier layer, an optical compensation layer, etc.
  • a functional layer may be applied.
  • the retardation in the front direction at a wavelength of 550 nm was measured using an automatic birefringence meter (manufactured by Oji Scientific Instruments, KOBRA-21).
  • the retardation in the front direction is measured at intervals of 10 mm in the width direction of the optically anisotropic film, and the arithmetic average value of the measured values is set as the in-plane retardation Ro and the thickness direction retardation Rt.
  • the difference between the Rt maximum value and the Rt minimum value was defined as the variation in the thickness direction retardation Rt.
  • the optically anisotropic film used in the present invention has optical compensation functions such as color compensation and viewing angle compensation, and has the effect of improving the visibility of the liquid crystal display device.
  • it is a film whose birefringence is controlled in the width direction and the film forming direction, and a film having a retardation Rt in the thickness direction of 30 to 500 nm.
  • optically anisotropic film examples include a uniaxial film, a biaxial film, and a laminate thereof, which are appropriately selected according to the mode of the liquid crystal cell to be used.
  • optically anisotropic film of the present invention is characterized by having the following retardation.
  • the in-plane retardation Ro and the retardation Rt in the thickness direction are defined as nx (MD direction) and ny (TD direction) as the main in-plane refractive index of the film, and the refractive index in the thickness direction of the film.
  • nx MD direction
  • ny TD direction
  • Ro (nx ⁇ ny) ⁇ d
  • Rt ((nx + ny) / 2 ⁇ nz) ⁇ d.
  • Optically anisotropic films include those obtained by stretching a film containing a thermoplastic resin, those obtained by forming an optically anisotropic layer on an unstretched thermoplastic resin film, and optical films on a film containing a thermoplastic resin. After forming the isotropic layer, a stretched layer or the like can be used.
  • the stretched film may be in the form of a single layer or in the form of a plurality of layers.
  • thermoplastic resins cellulose esters, alicyclic olefin polymers, and polypropylene resins are particularly preferably used because they are excellent in transparency, low birefringence, dimensional stability, and the like.
  • a retardation increasing agent can be added to the thermoplastic resin as necessary.
  • a retardation increasing agent is a compound that, when added to a thermoplastic resin, increases the retardation as compared with the case of no addition.
  • a retardation increasing agent When a retardation increasing agent is added to the cellulose ester, it is preferably used in the range of 0.01 to 20% by mass and used in the range of 0.1 to 10% by mass with respect to 100% by mass of the cellulose acetate. More preferably, it is more preferably used in the range of 0.2 to 5% by mass, and most preferably in the range of 0.5 to 2% by mass.
  • the retardation increasing agent preferably has a maximum absorption in a wavelength region of 250 to 400 nm.
  • the retardation increasing agent preferably has substantially no absorption in the visible region.
  • the retardation increasing agent it is preferable to use a compound having at least two aromatic rings.
  • the “aromatic ring” includes an aromatic hetero ring in addition to an aromatic hydrocarbon ring.
  • the aromatic hydrocarbon ring is particularly preferably a 6-membered ring (that is, a benzene ring).
  • the aromatic heterocycle is generally an unsaturated heterocycle.
  • the aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring.
  • the aromatic heterocycle generally has the most double bonds.
  • a nitrogen atom, an oxygen atom and a sulfur atom are preferable, and a nitrogen atom is particularly preferable.
  • aromatic heterocycles include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring, pyran ring, pyridine ring , Pyridazine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring.
  • the aromatic ring is preferably a benzene ring, furan ring, thiophene ring, pyrrole ring, oxazole ring, thiazole ring, imidazole ring, triazole ring, pyridine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring.
  • the number of aromatic rings contained in the retardation increasing agent is preferably 2 to 20, more preferably 2 to 12, still more preferably 2 to 8, and most preferably 2 to 6. preferable.
  • the bonding relationship between two aromatic rings can be classified into (a) when a condensed ring is formed, (b) when directly linked by a single bond, and (c) when linked via a linking group (for aromatic rings). , Spiro bonds cannot be formed).
  • the bond relationship may be any of (a) to (c).
  • a uniaxial stretching method such as a method of stretching uniaxially in a transverse direction using a tenter; a gap between fixed clips is opened and a guide rail spreads simultaneously with stretching in the longitudinal direction.
  • Sequential biaxial stretching method that stretches in the transverse direction according to the angle, or stretches in the longitudinal direction using the difference in peripheral speed between rolls, then grips both ends of the clip and stretches in the transverse direction using a tenter Biaxial stretching method such as biaxial stretching method;
  • Tenter stretching machine that can add feed force or pulling force or pulling force with different left and right speeds in the horizontal or vertical direction, and horizontal and vertical feed speeds in the horizontal and vertical directions
  • Tenter extension that can apply force, pulling force or pulling force so that the moving distance is the same and the stretching angle ⁇ can be fixed or the moving distance is different. How to obliquely stretched with the machine: and the like.
  • the stretching temperature can be usually in the range of Tg to Tg + 50 ° C., where Tg is the glass transition temperature of the resin having the lowest glass transition temperature among the materials forming the optically anisotropic film, particularly the resin.
  • the optically anisotropic film can be formed by forming an anisotropic layer using a polymer compound or a liquid crystal compound on a support. These may be used alone or in combination.
  • polyamide polyimide
  • polyester polyether ketone, or the like
  • polyether ketone polyether ketone
  • JP-T-8-511812 International Publication No. WO94 / 24191
  • 2000-511296 International Publication No. WO97 / 44704
  • JP-T-8-511812 International Publication No. WO94 / 24191
  • 2000-511296 International Publication No. WO97 / 44704
  • the liquid crystalline compound may be a rod-like liquid crystal or a discotic liquid crystal, and these include a polymer liquid crystal or a low molecular liquid crystal, and those in which a low molecular liquid crystal is cross-linked and no longer exhibits liquid crystallinity.
  • rod-like liquid crystal examples include those described in JP-A No. 2000-304932.
  • Preferred examples of the discotic liquid crystal include those described in JP-A-8-50206.
  • the thickness of the optically anisotropic layer is preferably from 0.1 to 10 ⁇ m, more preferably from 0.5 to 5 ⁇ m, and most preferably from 0.7 to 5 ⁇ m.
  • the liquid crystal cell may be 3 to 10 ⁇ m in order to obtain high optical anisotropy.
  • the method for producing the optically anisotropic film including the optically anisotropic layer is not particularly limited.
  • the polymer film and / or the liquid crystal compound is applied to a film containing a thermoplastic resin or the like to form a coating film.
  • ⁇ Polarizing plate> The polarizing plate of the present invention will be described.
  • the polarizing plate can be produced by a general method.
  • the cellulose ester film of the present invention is preferably subjected to alkali saponification treatment, and the treated film is bonded to at least one surface of a polarizer prepared by immersing and stretching in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. .
  • an acrylic or urethane adhesive In the case of an optically anisotropic film other than the cellulose ester film, it is preferable to use an acrylic or urethane adhesive.
  • the polarizer of the present invention is a polyvinyl alcohol polarizing film, which includes a polyvinyl alcohol film dyed with iodine and a dichroic dye dyed.
  • 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.
  • a polarizing plate is formed by laminating one side of the cellulose ester film of the present invention on the surface of the polarizer. It is preferably bonded with an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like.
  • the long cellulose ester film produced by the melt casting film-forming method according to the present invention can be bonded with a long polarizer (polarizing film) by subjecting it to alkali saponification treatment.
  • the productive effect is obtained with a long length of 1, and the longer the length is 1500 m, 2500 m, and 5000 m, the higher the productive effect of manufacturing the polarizing plate.
  • the polarizing plate using the cellulose ester film of this invention is excellent in rework property, the effect that a polarizing plate yield improves can also be acquired.
  • the polarizing plate containing the cellulose ester film of the present invention can exhibit high display quality as compared with a normal polarizing plate.
  • the polarizing plate of the present invention includes an MVA (Multi-domain Vertical Alignment) mode, a PVA (Patterned Vertical Alignment) mode, a CPA (Continuous Pinweal Alignment) mode, an OCB (Optical AlignSensing mode) Can be used.
  • MVA Multi-domain Vertical Alignment
  • PVA Power Planar Alignment
  • CPA Continuous Pinweal Alignment
  • OCB Optical AlignSensing mode
  • the liquid crystal display device is applied as a device for colorization and moving image display, and the display quality is improved by the present invention, and the contrast is improved and the resistance of the polarizing plate is improved. .
  • Example 1 ⁇ Synthesis of cellulose ester> With reference to Example B of JP-T-6-501040, the amount of propionic acid, butyric acid, and acetic acid was adjusted, and the degree of acetyl group substitution, propionyl group substitution, and butyryl group substitution were as shown in Table 1. Six kinds of changed cellulose esters were synthesized.
  • the degree of substitution of the obtained cellulose ester was calculated based on ASTM-D817-96.
  • ⁇ Preparation of Polarizing Plate Protective Film 1 by Melting Method> Cellulose ester C-1, which has been dried at 80 ° C. for 6 hours (water content: 200 ppm), 100 parts by mass, plasticizer No.
  • the obtained mixture was melt-mixed at 235 ° C. using a twin-screw extruder and pelletized.
  • the cellulose ester film was produced using the production apparatus shown in FIG.
  • Pellets (water content 50 ppm) were melt extruded from a T die onto a first cooling roll having a surface temperature of 100 ° C. at a melting temperature of 245 ° C. using a single-screw extruder, with an initial film thickness of 128 ⁇ m and a width of 1.0 m. A cast film of 35 m / min was obtained.
  • the film was pressed on the first cooling roll with an elastic touch roll having a 2 mm thick metal surface.
  • the obtained film was first stretched at 195 ° C. in the film-forming direction at a stretching rate of 1000% / min at a stretching speed of 1000% / min at 195 ° C. using a stretching machine utilizing a roll peripheral speed difference to obtain a protective film 101 having a thickness of 80 ⁇ m.
  • a preheating zone a stretching zone, a holding zone, and a cooling zone (a neutral zone for ensuring thermal insulation between the zones is also provided between the zones).
  • the film was obtained in a stretching zone at 165 ° C. in a stretching zone, then cooled to 30 ° C., released from the clip, and the clip gripping part was cut off.
  • the mixture was filtered with Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution.
  • a main dope solution having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. A part of methylene chloride (about 40 parts by mass) was divided in advance, and the cellulose ester was added to a pressurized dissolution tank containing a solvent while stirring.
  • the main dope solution was prepared by filtration using 244.
  • the dope is sufficiently mixed by an in-line mixer (Toray static type in-pipe mixer Hi-Mixer, SWJ), and is 2 m in width by a belt casting apparatus. It was cast uniformly on a stainless steel band support, peeled off and dried.
  • in-line mixer Toray static type in-pipe mixer Hi-Mixer, SWJ
  • the film was stretched 60% at 195 ° C. and 15000% / min by a stretching machine utilizing the difference in peripheral speed of the roll, and further stretched 70% at 170 ° C. and 700% / min in the width direction by a tenter.
  • a comparative sample 123 was obtained.
  • Comparative Sample 1 and Comparative Sample 2 described in Example 1 of Japanese Patent Application Laid-Open No. 2007-2216 were produced as comparative samples, and they were designated Samples 125 and 126, respectively.
  • the samples 101 to 122, 125, and 126 were 0.01 parts by mass or less, and the samples 123 and 124 were 0.1%.
  • ⁇ Hard coat layer> The following hard coat layer composition was applied to a dry film thickness of 3.5 ⁇ m and dried at 80 ° C. for 1 minute. Next, it was cured under a condition of 150 mJ / cm 2 with a high-pressure mercury lamp (80 W) to produce a hard coat film having a hard coat layer.
  • the refractive index of the hard coat layer was 1.50.
  • the following medium refractive index layer composition was applied by an extrusion coater and dried for 1 minute at 80 ° C. and 0.1 m / second.
  • a non-contact floater was used until completion of finger touch drying (a state in which the coated surface was touched and felt dry).
  • a horizontal floater type air tumbler manufactured by Belmatik was used as the non-contact floater.
  • the static pressure in the floater was set to 9.8 kPa, and the floater was lifted uniformly in the width direction of about 2 mm and conveyed. After drying, a medium refractive index layer film having a medium refractive index layer was produced by curing by irradiating ultraviolet rays with 130 mJ / cm 2 using a high pressure mercury lamp (80 W).
  • the thickness of the middle refractive index layer of this middle refractive index layer film was 84 nm, and the refractive index was 1.66.
  • ⁇ Medium refractive index layer composition 20% ITO fine particle dispersion (average particle size 70 nm, isopropyl alcohol solution) 100 parts by mass Dipentaerythritol hexaacrylate 6.4 parts by mass Irgacure 184 (manufactured by Ciba Japan Co., Ltd.) 1.6 parts by mass Tetrabutoxy titanium 4.0 parts by mass 10% FZ-2207 (manufactured by Nippon Unicar Co., Ltd., propylene glycol) Monomethyl ether solution) 3.0 parts by mass Isopropyl alcohol 530 parts by mass Methyl ethyl ketone 90 parts by mass Propylene glycol monomethyl ether 265 parts by mass ⁇ High refractive index layer> On the medium refractive index layer, the following high refractive index layer composition was applied by an extrusion coater and dried at 80 ° C. and 0.1 m / second for 1 minute. At this time, a non-contact floater was used until completion of
  • the non-contact floater was under the same conditions as the formation of the middle refractive index layer. After drying, ultraviolet rays were irradiated by 130 mJ / cm 2 using a high pressure mercury lamp (80 W) and cured to produce a high refractive index layer film having a high refractive index layer.
  • ⁇ High refractive index layer composition > 95 parts by mass of tetra (n) butoxytitanium dimethylpolysiloxane (KF-96-1000CS manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by mass of ⁇ -methacryloxypropyltrimethoxysilane (KBM503 manufactured by Shin-Etsu Chemical Co., Ltd.) 5 parts by mass Propylene glycol monomethyl ether 1750 parts by mass Isopropyl alcohol 3450 parts by mass Methyl ethyl ketone 600 parts by mass
  • the thickness of the high refractive index layer of this high refractive index layer film was 50 ⁇ m and the refractive index was 1.82.
  • silica-based fine particles (cavity particles) were prepared.
  • Preparation of silica-based fine particles P-1) A mixture of 100 g of silica sol having an average particle diameter of 5 nm and a SiO 2 concentration of 20 parts by mass and 1900 g of pure water was heated to 80 ° C. The pH of this reaction mother liquor was 10.5, and 9000 g of 0.98 parts by mass of sodium silicate aqueous solution as SiO 2 and 9000 g of 1.02 parts by mass of sodium aluminate aqueous solution as Al 2 O 3 were simultaneously added to the mother liquor. did.
  • the reaction solution was cooled to room temperature and washed with an ultrafiltration membrane to prepare a SiO 2 .Al 2 O 3 core particle dispersion having a solid content concentration of 20 parts by mass.
  • a silicate solution SiO 2 2 obtained by dealkalizing a sodium silicate aqueous solution with a cation exchange resin.
  • step (c) the aluminum salt dissolved in the ultrafiltration membrane was separated while adding 10 L of hydrochloric acid aqueous solution of pH 3 and 5 L of pure water, and SiO 2 ⁇ Al from which some of the constituent components of the core particles forming the first silica coating layer were removed. A dispersion of 2 O 3 porous particles was prepared (step (c)).
  • a mixture of 1500 g of the above porous particle dispersion, 500 g of pure water, 1,750 g of ethanol and 626 g of 28% ammonia water is heated to 35 ° C., and then 104 g of ethyl silicate (28 parts by mass of SiO 2 ) is added.
  • the surface of the porous particles on which the first silica coating layer was formed was coated with a hydrolyzed polycondensate of ethyl silicate to form a second silica coating layer.
  • a dispersion of silica-based fine particles having a solid content concentration of 20 parts by mass was prepared by replacing the solvent with ethanol using an ultrafiltration membrane.
  • Table 3 shows the thickness, average particle diameter, MOx / SiO 2 (molar ratio), and refractive index of the first silica coating layer of the silica-based fine particles.
  • the average particle diameter was measured by a dynamic light scattering method, and the refractive index was measured by the following method using Series A and AA made by CARGILL as a standard refractive liquid.
  • ⁇ Measuring method of particle refractive index> (1) The particle dispersion is taken in an evaporator and the dispersion medium is evaporated. (2) This is dried at 120 ° C. to obtain a powder. (3) A standard refraction liquid having a known refractive index is dropped on a glass plate of a few drops, and the above powder is mixed therewith. (4) The operation of (3) above is performed with various standard refractive liquids, and the refractive index of the standard refractive liquid when the mixed liquid becomes transparent is used as the refractive index of the colloidal particles.
  • a coating solution is applied at a film thickness of 100 nm on the actinic radiation curable resin layer or the high refractive index layer by using a die coater method, dried at 120 ° C. for 1 minute, and then irradiated with ultraviolet rays to obtain a refractive index of 1.37.
  • the low refractive index layer was formed.
  • the obtained mixture was melt-mixed at 235 ° C. using a twin-screw extruder and pelletized. Pellets (moisture content of 50 ppm) were melted at a melting temperature of 250 ° C. on a first cooling roll having a surface temperature of 125 ° C. from a T-die using a single screw extruder combined with a metal leaf disk filter and a gear pump. The film was melt extruded and a cast film having a width of 1.0 m was obtained at a length of 15 m / min.
  • the film was pressed on the first cooling roll with an elastic touch roll having a 2 mm thick metal surface. Further, in a tenter having a preheating zone, a stretching zone, a holding zone, and a cooling zone, the film was stretched in the width direction at 155 ° C. at a stretching ratio of 55% and a stretching speed of 200% / min, and then cooled to 30 ° C. It was opened and the clip gripping part was cut off to obtain a film having a thickness of 40 ⁇ m.
  • optically anisotropic film had Ro of 50 nm, Rt of 130 nm, and Rt variation of 7 nm.
  • optically anisotropic film B In the production of the optically anisotropic film A, the cellulose ester is changed to a cellulose ester having an acetyl group substitution degree of 1.20, a propionyl group substitution degree of 1.25, and a total acyl group substitution degree of 2.45, and further stretching in the width direction.
  • An optically anisotropic film B was prepared in the same manner except that the film was stretched at a temperature of 150 ° C., a stretching ratio of 30%, and a stretching speed of 700%.
  • the obtained optically anisotropic film had Ro of 50 nm, Rt of 132 nm, and Rt variation of 12 nm.
  • the first cooling roll temperature was set to 110 ° C., and the film was produced at a speed of 30 m / min. Further, the stretching condition in the width direction was 160 ° C., the stretching ratio was 50%, the stretching speed.
  • An optically anisotropic film C was obtained in the same manner except that the film was stretched at 700%.
  • the obtained optically anisotropic film had Ro of 51 nm, Rt of 128 nm, and Rt variation of 18 nm.
  • the obtained mixture was melt-mixed at 235 ° C. using a twin-screw extruder and pelletized. Pellets (moisture content of 50 ppm) were melted at a temperature of 225 ° C. on a first cooling roll having a surface temperature of 105 ° C. from a T die using a single screw extruder combined with a metal leaf disk filter and a gear pump. The film was melt extruded and a cast film having a width of 1.0 m was obtained at a length of 15 m / min.
  • the film was pressed on the first cooling roll with an elastic touch roll having a 2 mm thick metal surface.
  • the film was stretched at 128 ° C. in the width direction at a stretching ratio of 45% and a stretching rate of 200% / min, and then cooled to 30 ° C. It was opened and the clip gripping part was cut off to obtain a film having a thickness of 40 ⁇ m.
  • the obtained optically anisotropic film had Ro of 49 nm, Rt of 141 nm, and Rt variation of 8 nm.
  • the film was stretched at 143 ° C in the width direction, with a stretching ratio of 75% and a stretching speed of 150% / min, and then cooled to 30 ° C, and then clipped. And the clip gripping part was cut off to obtain a film having a thickness of 40 ⁇ m.
  • optically anisotropic film had Ro of 48 nm, Rt of 138 nm, and Rt variation of 7 nm.
  • Polypropylene resin F704, manufactured by Idemitsu Petrochemical Co., Ltd.
  • F704 was dried at 70 ° C. for 2 hours to remove moisture, and then surfaced from the T die using a single screw extruder combined with a leaf disk-shaped polymer filter and gear pump.
  • a cast film having a width of 1.0 m was obtained at a length of 15 m / min on a cooling roll having a temperature of 105 ° C. and melt-extruded into a film at a melting temperature of 240 ° C.
  • the film is stretched at 140 ° C. in the width direction at a stretching ratio of 65% and a stretching speed of 150% / min, then cooled to 30 ° C., and then clipped. And the clip gripping part was cut off to obtain a film having a thickness of 40 ⁇ m.
  • the obtained optically anisotropic film had Ro of 50 nm, Rt of 143 nm, and Rt variation of 9 nm.
  • ⁇ Production of polarizing plate and liquid crystal display device> Alkaline saponification treatment
  • the produced protective films 101 to 126 and the optically anisotropic films A, B, C, D, E, and F were subjected to alkali saponification treatment as described below.
  • Saponification step 2.5M-NaOH 50 ° C 90 seconds Water washing step Water 30 ° C 45 seconds Neutralizer 10 parts HCl 30 ° C 45 seconds Water washing step Water 30 ° C 45 seconds After saponification treatment, water washing, neutralization, water washing in this order And then dried at 80 ° C.
  • Table 4 shows the evaluation results of hardness unevenness, flatness, light leakage, and color unevenness.
  • ⁇ Evaluation> ⁇ Hardness unevenness>
  • Each polarizing plate is allowed to stand for 100 hours at 60 ° C. and 90% RH, and after returning to 23 ° C. and 55% RH for 100 hours, using a pencil with a different hardness, a test method shown in JIS K5400 under a 1 kg load. The hardness test was conducted based on the above. Each polarizing plate was divided into 10 in the width direction of the antireflection film, the pencil hardness at each position was measured, and evaluated according to the following evaluation criteria.
  • A No unevenness is observed in the surface hardness at each position.
  • O A slight unevenness is observed in the surface hardness at each position.
  • X An unevenness is observed in the surface hardness at each position. If so, there is no practical problem.
  • Each liquid crystal display device was left for 100 hours at 60 ° C. and 90% RH, returned to 23 ° C. and 55% RH, and after 100 hours had elapsed, the liquid crystal display device was displayed in black, and light leakage in the screen was visually evaluated. And evaluated according to the following criteria.
  • A There is no light leakage.
  • O There are 1 to 2 weak light leaks.
  • ⁇ There are 1 to 2 strong light leaks.
  • X There are 3 or more strong light leaks.
  • Each liquid crystal display device is left for 100 hours at 60 ° C. and 90% RH, and after returning to 23 ° C. and 55% RH for 100 hours, the liquid crystal display device is brightly displayed in a dark room and visually observed from the front.
  • the evaluation was based on the following criteria.
  • the samples according to the present invention were found to have almost no hardness unevenness and excellent flatness. It was also found that there was no light leakage and no color unevenness and excellent visibility. On the other hand, in samples other than the present invention, the hardness unevenness or flatness was greatly inferior, and the visibility of light leakage or color unevenness was inferior.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Polarising Elements (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)

Abstract

A polarizer is provided which is inhibited from suffering hardness unevenness and flatness unevenness in a high-temperature high-humidity environment and is highly reduced in light leakage and color unevenness. Also provided is a liquid-crystal display employing the polarizer. The polarizer comprises a polarizing element and two polarizer-protecting films (1, 2) between which the polarizing element is sandwiched. The polarizer is characterized in that the polarizer-protecting film (1) is a cellulose ester film satisfying both of the following expressions (A1) and (A2), having a solvent content of 0.01 mass% or lower, and having a sound velocity at 100°C in at least one of the machine direction and the transverse direction of 1.6-2.2 km/s, and that the polarizer-protecting film (2) is an optically anisotropic film having fluctuations in thickness-direction retardation (Rt) of 10 nm or less. Expression (A1) 2.0≤X+Y≤3.0 Expression (A2) 1.0≤Y≤2.5 (In the expressions, X indicates the degree of acetyl substitution of the cellulose ester; and Y indicates the degree of propionyl or butyryl substitution of the ester.)

Description

偏光板、偏光板保護フィルムの製造方法および液晶表示装置Polarizing plate, polarizing plate protective film manufacturing method, and liquid crystal display device
　本発明の目的は、偏光板および液晶表示装置に関し、特に高温高湿環境下においても硬度むらと平面性の発生を抑制し、光漏れや色むらに優れる偏光板、およびこの偏光板を有する液晶表示装置に関する。 An object of the present invention relates to a polarizing plate and a liquid crystal display device, and in particular, a polarizing plate that suppresses the occurrence of unevenness of hardness and flatness even in a high temperature and high humidity environment and is excellent in light leakage and unevenness of color, and a liquid crystal having the polarizing plate The present invention relates to a display device.
　近年、液晶表示装置はその普及に伴い、さらなる薄型化、大型化、また高性能化がすすみ、それに伴って、保護フィルムであるセルロースエステルフィルムにおいても、高い性能が求められている。 In recent years, with the spread of liquid crystal display devices, further reduction in thickness, size, and performance have been promoted, and accordingly, high performance is also required for cellulose ester films that are protective films.
　特に液晶表示装置の大型化に伴い、従来では問題とされなかった程度の色むらや光漏れという問題が顕在化し、これらの問題への対処が求められており、セルロースエステルフィルムの物性を調整することでこれらの特性を向上させる手段が模索されている。 In particular, with the increase in size of liquid crystal display devices, problems such as color unevenness and light leakage, which were not considered to be problems in the past, have become apparent, and measures for these problems have been demanded, and the physical properties of cellulose ester films are adjusted. Thus, a means for improving these characteristics is being sought.
　特許文献１では、光漏れという問題がセルロースエステルフィルムの音速と関連することに着目し、セルロースエステルフィルムの溶液流延製膜時における残留溶媒量とフィルム乾燥温度により音速を調整し、その結果光漏れを抑え、液晶表示装置の表示品位を改善するという技術を提案している。 In Patent Document 1, focusing on the fact that the problem of light leakage is related to the sound speed of the cellulose ester film, the sound speed is adjusted according to the residual solvent amount and the film drying temperature during solution casting of the cellulose ester film. A technique for suppressing leakage and improving display quality of a liquid crystal display device is proposed.
　しかし、溶液流延製膜法の音速調整技術では、最終的なフィルム中の残留溶媒が紫外線吸収剤等の添加剤の移動を生じさせることでフィルム内部の均質性を損なわせ、結果セルロースエステルフィルムを偏光板化した場合に、低高湿の繰り返しによるカール（湿度カール）の発生や、液晶表示装置の色むらを誘発させてしまうことが判明した。 However, in the sound velocity adjustment technology of the solution casting film forming method, the residual solvent in the final film causes the movement of additives such as UV absorbers, thereby impairing the homogeneity inside the film, resulting in the cellulose ester film. It has been found that when the film is made into a polarizing plate, curling (humidity curling) due to repeated low and high humidity and color unevenness of the liquid crystal display device are induced.
　一方、残留溶媒を削減する方法としては溶融流延製膜法が知られており（特許文献２）、特許文献３にはこの方法を用いて、セルロースエステルフィルムの湿度カールを改良する技術が開示されている。 On the other hand, a melt casting film forming method is known as a method for reducing residual solvent (Patent Document 2), and Patent Document 3 discloses a technique for improving humidity curl of a cellulose ester film using this method. Has been.
　特に特許文献３では、弾性率が１．５～２．９５ｋＮ／ｍ2であることが必要とされることが記載されている。 In particular, Patent Document 3 describes that the elastic modulus is required to be 1.5 to 2.95 kN / m 2 .
　しかしながら、本発明者らの検討によれば、この偏光板の場合、低湿高湿の繰り返しだけでなく、今後期待される、四季を通した屋外での用途に求められる高温高湿環境下では、偏光板の硬度と平面性が大きく劣化してしまい、液晶の光漏れを誘発することが判明した。
特開２００５－１７５７４号公報 特開２０００－３５２６２０号公報 特開２００７－２２１６号公報 However, according to the study of the present inventors, in the case of this polarizing plate, not only the repetition of low humidity and high humidity, but also in the high temperature and high humidity environment required for outdoor use throughout the season, which is expected in the future, It has been found that the hardness and flatness of the polarizing plate are greatly deteriorated to induce light leakage of the liquid crystal.
JP 2005-17574 A JP 2000-352620 A Japanese Patent Laid-Open No. 2007-2216
　本発明は、高温高湿環境下で硬度むらと平面性の発生を抑制し、光漏れや色むらに優れる偏光板、およびこの偏光板を有する液晶表示装置を提供することを目的とする。 An object of the present invention is to provide a polarizing plate that suppresses the occurrence of unevenness in hardness and flatness in a high-temperature and high-humidity environment, and is excellent in light leakage and color unevenness, and a liquid crystal display device having this polarizing plate.
　本発明の上記課題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．偏光子と、この偏光子を挟む２枚の偏光板保護フィルム１および２とからなる偏光板において、前記偏光板保護フィルム１は、下記式（Ａ１）および（Ａ２）を同時に満足し、含有溶媒量が０．０１質量％以下であり、１００℃における製膜方向または幅手方向の少なくとも一方の音速が１．６～２．２ｋｍ／ｓであるセルロースエステルフィルムであり、前記偏光板保護フィルム２は、その厚み方向のレターデーションＲｔのばらつきが１０ｎｍ以下である光学異方性フィルムであることを特徴とする偏光板。 1. In the polarizing plate comprising a polarizer and two polarizing plate protective films 1 and 2 sandwiching the polarizer, the polarizing plate protective film 1 satisfies the following formulas (A1) and (A2) at the same time, and contains a solvent The polarizing plate protective film 2 is a cellulose ester film having an amount of 0.01% by mass or less and a sound velocity of at least one of a film forming direction and a width direction at 100 ° C. of 1.6 to 2.2 km / s. Is an optically anisotropic film having a variation in retardation Rt in the thickness direction of 10 nm or less.
　　式（Ａ１）　２．０≦Ｘ＋Ｙ≦３．０
　　式（Ａ２）　１．０≦Ｙ≦２．５
（式中、Ｘはセルロースエステルのアセチル基の置換度、Ｙはプロピオニル基またはブチリル基の置換度を表す。）
　２．前記音速が、０．９≦音速（ＴＤ）／音速（ＭＤ）≦１．１の関係となることを特徴とする前記１に記載の偏光板。
（ＭＤは製膜方向、ＴＤは幅手方向を表す）
　３．前記１または２に記載の偏光板に使用する偏光板保護フィルムの製造方法であって該偏光板保護フィルムは、溶融製膜によって製膜され、かつフィルムの製膜方向に下記式（Ｂ）で表される延伸速度が１０００％／ｍｉｎ～３００００％／ｍｉｎで延伸することにより得られることを特徴とする前記１または２に記載の偏光板に使用する偏光板保護フィルムの製造方法。 Formula (A1) 2.0 ≦ X + Y ≦ 3.0
Formula (A2) 1.0 ≦ Y ≦ 2.5
(In the formula, X represents the degree of substitution of the acetyl group of the cellulose ester, and Y represents the degree of substitution of the propionyl group or butyryl group.)
2. 2. The polarizing plate according to 1 above, wherein the speed of sound has a relationship of 0.9 ≦ sound speed (TD) / sound speed (MD) ≦ 1.1.
(MD represents the film forming direction and TD represents the width direction)
3. It is a manufacturing method of the polarizing plate protective film used for the polarizing plate of said 1 or 2, Comprising: This polarizing plate protective film is formed into a film by melt film-forming, and it is the following formula (B) in the film-forming direction of a film 3. The method for producing a polarizing plate protective film used for the polarizing plate according to 1 or 2 above, wherein the polarizing plate is obtained by stretching at a stretching speed of 1000% / min to 30000% / min.
　式（Ｂ）
　延伸速度（％／ｍｉｎ）＝｛（延伸後寸法／延伸前寸法）－１｝×１００（％）／延伸に要する時間（ｍｉｎ）
　４．前記１または２記載の偏光板を備えることを特徴とする液晶表示装置。 Formula (B)
Stretching speed (% / min) = {(dimension after stretching / dimension before stretching) -1} × 100 (%) / time required for stretching (min)
4). A liquid crystal display device comprising the polarizing plate according to 1 or 2 above.
　本発明の偏光板によれば、高温高湿環境下で硬度むらと平面性の発生を抑制し、光漏れや色むらに優れるという効果がある。 The polarizing plate of the present invention has the effect of suppressing the occurrence of unevenness of hardness and flatness in a high temperature and high humidity environment and is excellent in light leakage and color unevenness.
本発明の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概略フローシートである。It is a general | schematic flow sheet of the apparatus which enforces the manufacturing method of the cellulose-ester film of this invention.
符号の説明Explanation of symbols
　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、１１、１３、１４、１５　搬送ロール
　１０　セルロースエステルフィルム
　１６　巻取り装置 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, 11, 13, 14, 15 Transport roll 10 Cellulose ester film 16 Winding 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。
＜偏光板＞
　本発明の偏光板は、偏光子と、この偏光子を挟む２枚の偏光板保護フィルム１および２とからなる偏光板において、前記偏光板保護フィルム１は、下記式（Ａ１）および（Ａ２）を同時に満足し、含有溶媒量が０．０１質量％以下、１００℃における製膜方向または幅手方向の少なくとも一方の音速が１．６～２．２ｋｍ／ｓであるセルロースエステルフィルムであり、前記偏光板保護フィルム２は、その厚み方向のレターデーションＲｔのばらつきが１０ｎｍ以下である光学異方性フィルムであることを特徴とする。 The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto.
<Polarizing plate>
In the polarizing plate of the present invention, a polarizing plate comprising a polarizer and two polarizing plate protective films 1 and 2 sandwiching the polarizer, the polarizing plate protective film 1 has the following formulas (A1) and (A2): And a cellulose ester film having a solvent content of 0.01% by mass or less and a sound velocity of at least one of the film forming direction and the width direction at 100 ° C. of 1.6 to 2.2 km / s, The polarizing plate protective film 2 is an optically anisotropic film having a variation in retardation Rt in the thickness direction of 10 nm or less.
　　式（Ａ１）　２．０≦Ｘ＋Ｙ≦３．０
　　式（Ａ２）　１．０≦Ｙ≦２．５
（式中、Ｘはセルロースエステルのアセチル基の置換度、Ｙはプロピオニル基またはブチリル基の置換度を表す。）
〈偏光板保護フィルム１〉
　本発明の偏光板保護フィルム１は、１００℃における、少なくともフィルム製膜方向か幅手方向のどちらか一方の音速が１．６～２．２ｋｍ／ｓであるセルロースエステルフィルムであることが特徴である。 Formula (A1) 2.0 ≦ X + Y ≦ 3.0
Formula (A2) 1.0 ≦ Y ≦ 2.5
(In the formula, X represents the degree of substitution of the acetyl group of the cellulose ester, and Y represents the degree of substitution of the propionyl group or butyryl group.)
<Polarizing plate protective film 1>
The polarizing plate protective film 1 of the present invention is characterized in that it is a cellulose ester film having a sound velocity of at least one of the film forming direction and the width direction at 100 ° C. of 1.6 to 2.2 km / s. is there.
　このような音速を有するセルロースエステルフィルムは、上記式（Ａ１）および（Ａ２）を同時に満足するセルロースエステル、および添加剤を含む組成物を溶融流延製膜する
ことにより得ることができる。 The cellulose ester film having such a sound speed can be obtained by melt casting a composition containing a cellulose ester that satisfies the above formulas (A1) and (A2) and an additive at the same time.
　具体的には、流動性を示す温度まで上記組成物を加熱溶融して溶融物とし、該溶融物を流延し冷却したあと、少なくともフィルムの製膜方向に下記式（１）で表される延伸速度が１０００％／ｍｉｎ～３００００％／ｍｉｎで延伸し、好ましくはさらに幅手方向に延伸速度が４００％／ｍｉｎ～１５００％／ｍｉｎで延伸することで、少なくともフィルム製膜方向か幅手方向のどちらか一方の音速が１．６～２．２ｋｍ／ｓであるセルロースエステルフィルムを得ることができる。 Specifically, the composition is heated and melted to a temperature exhibiting fluidity to form a melt, and after casting and cooling the melt, at least the film forming direction is represented by the following formula (1). The film is stretched at a stretching speed of 1000% / min to 30000% / min, and preferably further stretched in the width direction at a stretching speed of 400% / min to 1500% / min. A cellulose ester film having a sound velocity of either 1.6 to 2.2 km / s can be obtained.
　式（１）
　延伸速度（％／ｍｉｎ）＝｛（延伸後寸法／延伸前寸法）－１｝×１００（％）／延伸に要する時間（ｍｉｎ）
　本発明は、溶液流延製膜法ではフィルムが破断してしまい使用することができなかった範囲の延伸速度を、溶融流延製膜法で実現することにより、セルロースエステルフィルムの音速を１．６～２．２ｋｍ／ｓの範囲に調整し、色むらと光漏れに優れたセルロースエステルフィルムが得られることを見出したものである。 Formula (1)
Stretching speed (% / min) = {(dimension after stretching / dimension before stretching) -1} × 100 (%) / time required for stretching (min)
The present invention achieves the sound velocity of the cellulose ester film by realizing a stretching speed in a range in which the film was broken by the solution casting film forming method and could not be used by the melt casting film forming method. It has been found that a cellulose ester film having an excellent color unevenness and light leakage can be obtained by adjusting to a range of 6 to 2.2 km / s.
　ここで延伸速度を調整することで、所望の音速をもったセルロースエステルフィルムが得られる機構については、本発明者は以下のように推察している。 The inventor has inferred the mechanism for obtaining a cellulose ester film having a desired sound speed by adjusting the stretching speed as follows.
　同じ延伸倍率であっても延伸速度を大きくすると、フィルムにかかる荷重がより高くなり、それにより所望の音速をもったセルロースエステルフィルムを得ることができる。 Even when the stretching ratio is the same, if the stretching speed is increased, the load applied to the film becomes higher, and thereby a cellulose ester film having a desired sound speed can be obtained.
　さらに本発明においては、音速が製膜方向（ＭＤ）と幅手方向（ＴＤ）で以下の関係となることが光漏れに対し特に好ましいことを見出した。 Furthermore, in the present invention, it has been found that it is particularly preferable for light leakage that the sound velocity has the following relationship in the film forming direction (MD) and the width direction (TD).
　式（２）０．９≦音速（ＴＤ）／音速（ＭＤ）≦１．１
　本発明のセルロースエステルフィルムの音速は、ＳＯＮＩＣ　ＳＨＥＥＴ　ＴＥＳＴＥＲ（ＳＳＴ－１１０型、野村商事（株）製）を用いて、１００℃の環境下３時間放置したフィルムにおいて、同環境下で測定することができる。 Formula (2) 0.9 ≦ Sonic velocity (TD) / Sonic velocity (MD) ≦ 1.1
The speed of sound of the cellulose ester film of the present invention can be measured using a SONIC SHEET TESTER (SST-110 type, manufactured by Nomura Corporation) in a film that has been left for 3 hours in an environment of 100 ° C. it can.
　次に本発明者は、高温高湿下での硬度むらと平面性劣化は、含有溶媒の実質ないフィルムの場合セルロースエステルの置換基に非常に強く依存することをつきとめた。 Next, the present inventor has found that the hardness unevenness and flatness deterioration under high temperature and high humidity depend very strongly on the substituent of the cellulose ester in the case of a film substantially free of the contained solvent.
　即ち、炭素数３以上に置換基が長くなると熱に対して分子内で置換基が傾き易くなってしまう。従って、炭素数３以上の置換基の数が増すと、フィルムの各々の微小領域内でバラツキが発生してしまうことに起因していると考えられる。 That is, when the substituent becomes longer with 3 or more carbon atoms, the substituent tends to be inclined in the molecule with respect to heat. Therefore, it is considered that when the number of substituents having 3 or more carbon atoms is increased, variation occurs in each minute region of the film.
　具体的には、高温高湿環境下に偏光板が曝されると、画面内で保護フィルムが不均一に塑性変形が生じてしまい硬度や平面性にむらを生じさせてしまう。 Specifically, when the polarizing plate is exposed to a high-temperature and high-humidity environment, the protective film is non-uniformly plastically deformed in the screen, resulting in uneven hardness and flatness.
　溶融製膜法によれば、流延製膜のための溶媒を使用しないことから、製膜乾燥後の残留溶媒量（フィルム中に最終的に含有される含有溶媒量）をセルロースエステルフィルム全体の０．０１質量％とすることができる。 According to the melt film-forming method, since no solvent for casting film formation is used, the residual solvent amount after film-forming and drying (the amount of solvent that is finally contained in the film) is calculated for the entire cellulose ester film. It can be 0.01 mass%.
　ここで含有溶媒とは、流延製膜において使用した沸点１２０℃以下の有機溶媒であって、製膜終了後のフィルムの状態にあってもフィルム中に残留している溶媒をいう。 Here, the contained solvent is an organic solvent having a boiling point of 120 ° C. or lower used in casting film formation, and is a solvent remaining in the film even after film formation.
　本発明のセルロースエステルフィルムは、セルロースエステルおよび添加剤とからなる。
《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、炭素数２～２２程度のカルボン酸エステルであり、芳香族カルボン酸のエステルでもよく、特にセルロースの低級脂肪酸エステルであることが好ましい。 The cellulose ester film of the present invention comprises a cellulose ester and an additive.
《Cellulose ester》
The cellulose ester used in the present invention is a carboxylic acid ester having about 2 to 22 carbon atoms, may be an aromatic carboxylic acid ester, and is particularly preferably a lower fatty acid ester of cellulose.
　セルロースの低級脂肪酸エステルにおける低級脂肪酸とは炭素原子数が６以下の脂肪酸を意味している。水酸基に結合するアシル基は、直鎖であっても分岐してもよく、また環を形成してもよい。さらに別の置換基が置換してもよい。 The lower fatty acid in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms. The acyl group bonded to the hydroxyl group may be linear or branched or may form a ring. Furthermore, another substituent may be substituted.
　同じ置換度である場合、前記炭素数が多いとフィルムの腰がなくなるため、炭素数としては炭素数２～６のアシル基の中で選択することが好ましい。 When the degree of substitution is the same, the film becomes stiff when the number of carbon atoms is large. Therefore, the carbon number is preferably selected from acyl groups having 2 to 6 carbon atoms.
　本発明のセルロースエステルとしては、前記（Ａ１）および（Ａ２）を同時に満足するものが必要となるが、Ｙがプロピオニル基であって、１．１≦Ｙ≦２．０が好ましく、さらに１．１≦Ｙ≦１．５が特に光漏れに対し好ましい。 The cellulose ester of the present invention is required to satisfy the above (A1) and (A2) at the same time. Y is a propionyl group, preferably 1.1 ≦ Y ≦ 2.0. 1 ≦ Y ≦ 1.5 is particularly preferable for light leakage.
　本発明における置換度範囲は、延伸速度を上げることができ、さらに音速も本発明の範囲を達成することができる。 The substitution degree range in the present invention can increase the stretching speed, and the sound speed can also achieve the range of the present invention.
　アシル基の置換度の測定方法はＡＳＴＭ－Ｄ８１７－９６に準じて測定することができる。 The method for measuring the substitution degree of the acyl group can be measured according to ASTM-D817-96.
　セルロースエステルの分子量は数平均分子量（Ｍｎ）で６００００～３０００００のものが好ましく、７００００～２０００００のものがさらに好ましい。本さら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４．０以下であることが好ましく、さらに好ましくは１．４～２．３である。 The molecular weight of cellulose ester is preferably 60000-300000, more preferably 70000-200000 in terms of number average molecular weight (Mn). The cellulose ester further used preferably has a weight average molecular weight (Mw) / number average molecular weight (Mn) ratio of 4.0 or less, more preferably 1.4 to 2.3.
　セルロースエステルの平均分子量および分子量分布は、ゲルパーミエーションクロマトグラフィー（ＧＰＣ）を用い測定できるので、これを用いて数平均分子量（Ｍｎ）、重量平均分子量（Ｍｗ）を算出し、その比を計算することができる。 Since the average molecular weight and molecular weight distribution of cellulose ester can be measured using gel permeation chromatography (GPC), the number average molecular weight (Mn) and the weight average molecular weight (Mw) are calculated using this, and the ratio is calculated. be able to.
　測定条件は以下の通りである。 The measurement conditions are as follows.
　溶媒：　　　メチレンクロライド
　カラム：　　Ｓｈｏｄｅｘ　Ｋ８０６，Ｋ８０５，Ｋ８０３Ｇ（昭和電工（株）製を３本接続して使用した）
　カラム温度：２５℃
　試料濃度：　０．１質量％
　検出器：　　ＲＩ　Ｍｏｄｅｌ　５０４（ＧＬサイエンス社製）
　ポンプ：　　Ｌ６０００（日立製作所（株）製）
　流量：　　　１．０ｍｌ／ｍｉｎ
　校正曲線：　標準ポリスチレンＳＴＫ　ｓｔａｎｄａｒｄ　ポリスチレン（東ソー（株）製）Ｍｗ＝１，０００，０００～５００迄の１３サンプルによる校正曲線を使用した。１３サンプルは、ほぼ等間隔に用いることが好ましい。 Solvent: Methylene chloride Column: Shodex K806, K805, K803G (Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (manufactured by GL Sciences)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Co., Ltd.) Mw = 1,000,000-500 calibration curves with 13 samples were used. The 13 samples are preferably used at approximately equal intervals.
　本発明の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傾向がある。 The residual sulfuric acid content in the cellulose ester of 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. When the residual sulfuric acid content exceeds 45 ppm, there is a tendency that deposits on the die lip portion during heat melting increase.
　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傾向がある。従って１～３０ｐｐｍの範囲がより好ましい。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。 Also, there is a tendency to break easily during slitting during hot stretching or after hot stretching. Therefore, the range of 1 to 30 ppm is more preferable. The residual sulfuric acid content can be measured by the method prescribed in ASTM D817-96.
　本発明の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。上記の範囲であると、ダイリップ部の付着物の増加がなく、また破断しにくい。 The free acid content in the cellulose ester of the present invention is preferably 1 to 500 ppm. Within the above range, there is no increase in deposits on the die lip and it is difficult to break.
　さらに、本発明については、１～１００ｐｐｍの範囲であることが好ましく、さら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。 Furthermore, in the present invention, it is preferably in the range of 1 to 100 ppm, and it is 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、さら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、およ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。 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.
　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、ある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。 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 if it is a poor solvent. Low molecular organic impurities can be removed.
　また、本発明の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、さらに１００個／ｃｍ2以下であることが好ましく、５０個／ｃｍ2以下であることが好ましく、３０個／ｃｍ2以下であることが好ましく、１０個／ｃｍ2以下であることが好ましいが、皆無であることが最も好ましい。 Moreover, it is preferable that the cellulose ester of this invention has few bright spot foreign materials when it is made into a film. The bright spot foreign matter preferably has a bright spot diameter of 0.01 mm or more and 200 pieces / cm 2 or less, more preferably 100 pieces / cm 2 or less, and preferably 50 pieces / cm 2 or less. 30 / cm 2 or less, preferably 10 / cm 2 or less, and most preferably none.
　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、さらに１００個／ｃｍ2以下であることが好ましく、５０個／ｃｍ2以下であることが好ましく、３０個／ｃｍ2以下であることが好ましく、１０個／ｃｍ2以下であることが好ましいが、皆無であることが最も好ましい。
《添加剤》
　本発明におけるセルロースエステルフィルムには、フィルムに加工性を付与する可塑剤、フィルムの劣化を防止する酸化防止剤、紫外線吸収機能を付与する紫外線吸収剤、フィルムに滑り性を付与する微粒子（マット剤）、フィルムのレターデーションを調整するレターデーション調整剤等の添加剤を含有させても良い。 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. The number is preferably 30 pieces / cm 2 or less, more preferably 10 pieces / cm 2 or less, and most preferably none.
"Additive"
The cellulose ester film in the present invention includes a plasticizer that imparts processability to the film, an antioxidant that prevents deterioration of the film, an ultraviolet absorber that imparts an ultraviolet absorbing function, and fine particles that impart slipperiness to the film (matting agent). ), Additives such as a retardation adjusting agent for adjusting the retardation of the film may be contained.
　（可塑剤）
　本発明に係るセルロースエステルフィルムの製造においては、フィルム形成材料中に少なくとも１種の可塑剤を含有することが好ましい。 (Plasticizer)
In the production of the cellulose ester film according to the present invention, it is preferable that the film forming material contains at least one plasticizer.
　本発明では、可塑剤は単独あるいは２種以上混合して用いることができるが、少なくとも１種は有機酸と３価以上のアルコールが縮合した構造を有する分子量３５０～１５００の多価アルコールエステル系可塑剤であることが好ましい。 In the present invention, plasticizers can be used alone or in combination of two or more, but at least one plasticizer has a structure in which an organic acid and a trihydric or higher alcohol are condensed and has a molecular weight of 350 to 1500. It is preferable that it is an agent.
　使用することができるその他の可塑剤としては特に限定されないが、好ましくは、多価カルボン酸エステル系可塑剤、グリコレート系可塑剤、フタル酸エステル系可塑剤、脂肪酸エステル系可塑剤、ポリマー可塑剤、糖エステル可塑剤等から選択される。 Other plasticizers that can be used are not particularly limited, but are preferably polycarboxylic acid ester plasticizers, glycolate plasticizers, phthalate ester plasticizers, fatty acid ester plasticizers, polymer plasticizers. Selected from sugar ester plasticizers and the like.
　可塑剤の使用量は、セルロース誘導体に対して１質量％未満ではフィルムの透湿度を低減させる効果が少ないため好ましくなく、２０質量％を越えると高温耐久時のフィルムの物性が劣化するため、１～２０質量％が好ましい。 If the amount of the plasticizer used is less than 1% by mass relative to the cellulose derivative, the effect of reducing the moisture permeability of the film is small, which is not preferable. If the amount exceeds 20% by mass, the physical properties of the film at high temperature durability deteriorate. ~ 20% by weight is preferred.
　（多価アルコールエステル系可塑剤）
　本発明の多価アルコールエステル系可塑剤は、有機酸と多価アルコールとのエステルでありその有機酸は、下記一般式（１）で表される。 (Polyhydric ester plasticizer)
The polyhydric alcohol ester plasticizer of the present invention is an ester of an organic acid and a polyhydric alcohol, and the organic acid is represented by the following general formula (1).
Figure JPOXMLDOC01-appb-C000001
Figure JPOXMLDOC01-appb-C000001
　式中、Ｒ1～Ｒ5は水素原子またはシクロアルキル基、アラルキル基、アルコキシ基、シクロアルコキシ基、アリールオキシ基、アラルキルオキシ基、アシル基、カルボニルオキシ基、オキシカルボニル基、オキシカルボニルオキシ基を表し、これらはさらに置換基を有していてよい。Ｌは連結基を表し、置換または無置換のアルキレン基、酸素原子、または直接結合を表す。 In the formula, R 1 to R 5 represent a hydrogen atom or a cycloalkyl group, an aralkyl group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an aralkyloxy group, an acyl group, a carbonyloxy group, an oxycarbonyl group, or an oxycarbonyloxy group. These may be further substituted. L represents a linking group and represents a substituted or unsubstituted alkylene group, an oxygen atom, or a direct bond.
　Ｒ1～Ｒ5で表されるシクロアルキル基としては、炭素数３～８のシクロアルキル基が好ましく、具体的にはシクロプロピル、シクロペンチル、シクロヘキシル等の基である。これらの基は置換されていてもよく、好ましい置換基としては、ハロゲン原子、例えば、塩素原子、臭素原子、フッ素原子等、ヒドロキシル基、アルキル基、アルコキシ基、シクロアルコキシ基、アラルキル基（このフェニル基にはアルキル基またはハロゲン原子等によってさらに置換されていてもよい）、ビニル基、アリル基等のアルケニル基、フェニル基（このフェニル基にはアルキル基またはハロゲン原子等によってさらに置換されていてもよい）、フェノキシ基（このフェニル基にはアルキル基またはハロゲン原子等によってさらに置換されていてもよい）、アセチル基、プロピオニル基等の炭素数２～８のアシル基、またアセチルオキシ基、プロピオニルオキシ基等の炭素数２～８の無置換のカルボニルオキシ基等が挙げられる。 The cycloalkyl group represented by R 1 to R 5 is preferably a cycloalkyl group having 3 to 8 carbon atoms, specifically, a group such as cyclopropyl, cyclopentyl, or cyclohexyl. These groups may be substituted, and preferred substituents include halogen atoms such as chlorine atom, bromine atom, fluorine atom, hydroxyl group, alkyl group, alkoxy group, cycloalkoxy group, aralkyl group (this phenyl group). The group may be further substituted with an alkyl group or a halogen atom), an alkenyl group such as a vinyl group or an allyl group, or a phenyl group (this phenyl group may be further substituted with an alkyl group or a halogen atom). Phenoxy group (this phenyl group may be further substituted with an alkyl group or a halogen atom), acyl groups having 2 to 8 carbon atoms such as acetyl group and propionyl group, acetyloxy group, propionyloxy And an unsubstituted carbonyloxy group having 2 to 8 carbon atoms, such as a group.
　Ｒ1～Ｒ5で表されるアラルキル基としては、ベンジル基、フェネチル基、γ－フェニルプロピル基等の基を表し、また、これらの基は置換されていてもよく、好ましい置換基としては、前記のシクロアルキル基に置換してもよい基を同様に挙げることができる。 The aralkyl group represented by R 1 to R 5 represents a benzyl group, a phenethyl group, a γ-phenylpropyl group, or the like. These groups may be substituted, and preferred substituents include The group which may be substituted with the said cycloalkyl group can be mentioned similarly.
　Ｒ1～Ｒ5で表されるアルコキシ基としては、炭素数１～８のアルコキシ基が挙げられ、具体的には、メトキシ、エトキシ、ｎ－プロポキシ、ｎ－ブトキシ、ｎ－オクチルオキシ、イソプロポキシ、イソブトキシ、２－エチルヘキシルオキシ、もしくはｔ－ブトキシ等の各アルコキシ基である。 Examples of the alkoxy group represented by R 1 to R 5 include an alkoxy group having 1 to 8 carbon atoms, and specifically include methoxy, ethoxy, n-propoxy, n-butoxy, n-octyloxy, isopropoxy , Alkoxy groups such as isobutoxy, 2-ethylhexyloxy, or t-butoxy.
　また、これらの基は置換されていてもよく、好ましい置換基としては、ハロゲン原子、例えば、塩素原子、臭素原子、フッ素原子等、ヒドロキシル基、アルコキシ基、シクロアルコキシ基、アラルキル基（このフェニル基にはアルキル基またはハロゲン原子等を置換していてもよい）、アルケニル基、フェニル基（このフェニル基にはアルキル基またはハロゲン原子等によってさらに置換されていてもよい）、アリールオキシ基（例えばフェノキシ基（このフェニル基にはアルキル基またはハロゲン原子等によってさらに置換されていてもよい））、アセチル基、プロピオニル基等のアシル基が、またアセチルオキシ基、プロピオニルオキシ基等の炭素数２～８の無置換のアシルオキシ基、またベンゾイルオキシ基等のアリールカルボニルオキシ基が挙げられる。 These groups may be substituted, and preferred substituents include halogen atoms such as chlorine atom, bromine atom, fluorine atom, hydroxyl group, alkoxy group, cycloalkoxy group, aralkyl group (this phenyl group). May be substituted with an alkyl group or a halogen atom), an alkenyl group, a phenyl group (this phenyl group may be further substituted with an alkyl group or a halogen atom), an aryloxy group (for example, phenoxy) An acyl group such as an acetyl group or a propionyl group, or an aryl group such as an acetyloxy group or a propionyloxy group. An unsubstituted acyloxy group or an arylcarbonyl such as a benzoyloxy group Alkoxy group.
　Ｒ1～Ｒ5で表されるシクロアルコキシ基としては、無置換のシクロアルコキシ基としては炭素数１～８のシクロアルコキシ基が挙げられ、具体的には、シクロプロピルオキシ、シクロペンチルオキシ、シクロヘキシルオキシ等の基が挙げられる。 Examples of the cycloalkoxy group represented by R 1 to R 5 include an unsubstituted cycloalkoxy group having 1 to 8 carbon atoms, specifically cyclopropyloxy, cyclopentyloxy, cyclohexyloxy. And the like.
　また、これらの基は置換されていてもよく、好ましい置換基としては、前記のシクロアルキル基に置換してもよい基を同様に挙げることができる。 In addition, these groups may be substituted, and preferred examples of the substituent include the same groups that may be substituted with the cycloalkyl group.
　Ｒ1～Ｒ5で表されるアリールオキシ基としては、フェノキシ基が挙げられるが、このフェニル基にはアルキル基またはハロゲン原子等前記シクロアルキル基に置換してもよい基として挙げられた置換基で置換されていてもよい。 Examples of the aryloxy group represented by R 1 to R 5 include a phenoxy group, and the phenyl group includes a substituent that may be substituted with the cycloalkyl group such as an alkyl group or a halogen atom. May be substituted.
　Ｒ1～Ｒ5で表されるアラルキルオキシ基としては、ベンジルオキシ基、フェネチルオキシ基等が挙げられ、これらの置換基はさらに置換されていてもよく、好ましい置換基としては、前記のシクロアルキル基に置換してもよい基を同様に挙げることができる。 Examples of the aralkyloxy group represented by R 1 to R 5 include a benzyloxy group, a phenethyloxy group, and the like. These substituents may be further substituted. Preferred substituents include the cycloalkyl group described above. The group which may be substituted with a group can be mentioned similarly.
　Ｒ1～Ｒ5で表されるアシル基としては、アセチル基、プロピオニル基等の炭素数２～８の無置換のアシル基が挙げられ（アシル基の炭化水素基としては、アルキル、アルケニル、アルキニル基を含む。）、これらの置換基はさらに置換されていてもよく、好ましい置換基としては、前記のシクロアルキル基に置換してもよい基を同様に挙げることができる。 Examples of the acyl group represented by R 1 to R 5 include an unsubstituted acyl group having 2 to 8 carbon atoms such as an acetyl group and a propionyl group (the hydrocarbon group of the acyl group includes alkyl, alkenyl, alkynyl). These substituents may be further substituted, and preferred substituents include the same groups that may be substituted with the cycloalkyl group.
　Ｒ1～Ｒ5で表されるカルボニルオキシ基としては、アセチルオキシ基、プロピオニルオキシ基等の炭素数２～８の無置換のアシルオキシ基（アシル基の炭化水素基としては、アルキル、アルケニル、アルキニル基を含む。）、またベンゾイルオキシ基等のアリールカルボニルオキシ基が挙げられるが、これらの基はさらに前記シクロアルキル基に置換してもよい基と同様の基により置換されていてもよい。 The carbonyloxy group represented by R 1 to R 5 is an unsubstituted acyloxy group having 2 to 8 carbon atoms such as acetyloxy group and propionyloxy group (the hydrocarbon group of the acyl group is alkyl, alkenyl, alkynyl). And arylcarbonyloxy groups such as a benzoyloxy group, and these groups may be further substituted with the same groups as those which may be substituted with the cycloalkyl group.
　Ｒ1～Ｒ5で表されるオキシカルボニル基としては、メトキシカルボニル基、エトキシカルボニル基、プロピルオキシカルボニル基等のアルコキシカルボニル基、またフェノキシカルボニル基等のアリールオキシカルボニル基を表す。 The oxycarbonyl group represented by R 1 to R 5 represents an alkoxycarbonyl group such as a methoxycarbonyl group, an ethoxycarbonyl group or a propyloxycarbonyl group, or an aryloxycarbonyl group such as a phenoxycarbonyl group.
　これらの置換基はさらに置換されていてもよく、好ましい置換基としては、前記のシクロアルキル基に置換してもよい基を同様に挙げることができる。 These substituents may be further substituted, and preferable substituents include the same groups that may be substituted with the cycloalkyl group.
　Ｒ1～Ｒ5で表されるオキシカルボニルオキシ基としては、メトキシカルボニルオキシ基等の炭素数１～８のアルコキシカルボニルオキシ基を表し、これらの置換基はさらに置換されていてもよく、好ましい置換基としては、前記のシクロアルキル基に置換してもよい基を同様に挙げることができる。 The oxycarbonyloxy group represented by R 1 to R 5 represents an alkoxycarbonyloxy group having 1 to 8 carbon atoms such as a methoxycarbonyloxy group, and these substituents may be further substituted and are preferably substituted. Examples of the group include the same groups that may be substituted on the cycloalkyl group.
　Ｒ1～Ｒ5のうちのいずれか同士で互いに連結し、環構造を形成していてもよい。 Any one of R 1 to R 5 may be connected to each other to form a ring structure.
　また、Ｌで表される連結基としては、置換または無置換のアルキレン基、酸素原子、または直接結合を表すが、アルキレン基としては、メチレン基、エチレン基、プロピレン基等の基であり、これらの基は、さらに前記のＲ1～Ｒ5で表される基に置換してもよい基としてあげられた基で置換されていてもよい。 The linking group represented by L represents a substituted or unsubstituted alkylene group, an oxygen atom, or a direct bond, and the alkylene group is a group such as a methylene group, an ethylene group, or a propylene group. This group may be further substituted with the above-mentioned groups which may be substituted with the groups represented by R 1 to R 5 .
　中でも、Ｌで表される連結基として特に好ましいのは直接結合であり芳香族カルボン酸である。 Among these, a direct bond and an aromatic carboxylic acid are particularly preferable as the linking group represented by L.
　また、これら本発明において可塑剤となるエステル化合物を構成する、前記一般式（１）で表される有機酸としては、少なくともＲ1またはＲ2に前記アルコキシ基、アシル基、オキシカルボニル基、カルボニルオキシ基、オキシカルボニルオキシ基を有するものが好ましい。また複数の置換基を有する化合物も好ましい。 In addition, the organic acid represented by the general formula (1) constituting the ester compound serving as a plasticizer in the present invention includes at least R 1 or R 2 having the alkoxy group, acyl group, oxycarbonyl group, carbonyl group. Those having an oxy group or an oxycarbonyloxy group are preferred. A compound having a plurality of substituents is also preferred.
　なお本発明においては３価以上のアルコールの水酸基を置換する有機酸は単一種であっても複数種であってもよい。 In the present invention, the organic acid substituting the hydroxyl group of the trivalent or higher alcohol may be a single type or a plurality of types.
　本発明における、前記一般式（１）で表される有機酸と反応して多価アルコールエステル化合物を形成する３価以上のアルコール化合物としては、好ましくは３～２０価の脂肪族多価アルコールであり、本発明おいて３価以上のアルコールは下記一般式（２）で表されるものが好ましい。 In the present invention, the trihydric or higher alcohol compound that reacts with the organic acid represented by the general formula (1) to form a polyhydric alcohol ester compound is preferably a trihydric to polyhydric aliphatic polyhydric alcohol. In the present invention, the trihydric or higher alcohol is preferably represented by the following general formula (2).
　一般式（２）　Ｒ′－（ＯＨ）ｍ
　式中、Ｒ′はｍ価の有機基、ｍは３以上の正の整数、ＯＨ基はアルコール性水酸基を表す。特に好ましいのは、ｍとしては３または４の多価アルコールである。 Formula (2) R ′-(OH) m
In the formula, R ′ represents an m-valent organic group, m represents a positive integer of 3 or more, and the OH group represents an alcoholic hydroxyl group. Particularly preferred is a polyhydric alcohol having 3 or 4 as m.
　好ましい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 preferred polyhydric alcohols include the following, but the present invention is not limited to these.
　アドニトール、アラビトール、１，２，４－ブタントリオール、１，２，３－ヘキサントリオール、１，２，６－ヘキサントリオール、グリセリン、ジグリセリン、エリスリトール、ペンタエリスリトール、ジペンタエリスリトール、トリペンタエリスリトール、ガラクチトール、イノシトール、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、トリメチロールエタン、キシリトール等を挙げることができる。 Adonitol, arabitol, 1,2,4-butanetriol, 1,2,3-hexanetriol, 1,2,6-hexanetriol, glycerin, diglycerin, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, ga Examples include lactitol, inositol, mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, and xylitol.
　特に、グリセリン、トリメチロールエタン、トリメチロールプロパン、ペンタエリスリトールが好ましい。 In particular, glycerin, trimethylolethane, trimethylolpropane and pentaerythritol are preferable.
　一般式（１）で表される有機酸と一般式（２）で表される３価以上の多価アルコールのエステルは、公知の方法により合成できる。実施例に代表的合成例を示したが、前記一般式（１）で表される有機酸と、一般式（２）で表される多価アルコールを例えば、酸の存在下縮合させエステル化する方法、また、有機酸をあらかじめ酸クロライドあるいは酸無水物としておき、多価アルコールと反応させる方法、有機酸のフェニルエステルと多価アルコールを反応させる方法等があり、目的とするエステル化合物により、適宜、収率のよい方法を選択することが好ましい。 An organic acid represented by the general formula (1) and an ester of a trihydric or higher polyhydric alcohol represented by the general formula (2) can be synthesized by a known method. In the examples, typical synthesis examples are shown. For example, the organic acid represented by the general formula (1) and the polyhydric alcohol represented by the general formula (2) are condensed and esterified in the presence of an acid, for example. There are a method, an organic acid in advance as an acid chloride or an acid anhydride, a method of reacting with a polyhydric alcohol, a method of reacting a phenyl ester of an organic acid and a polyhydric alcohol, etc. It is preferable to select a method with good yield.
　一般式（１）で表される有機酸と一般式（２）で表される３価以上の多価アルコールのエステルからなる可塑剤としては、下記一般式（３）で表される化合物が好ましい。 As a plasticizer comprising an organic acid represented by the general formula (1) and an ester of a trihydric or higher polyhydric alcohol represented by the general formula (2), a compound represented by the following general formula (3) is preferable. .
Figure JPOXMLDOC01-appb-C000002
Figure JPOXMLDOC01-appb-C000002
　式中、Ｒ6～Ｒ20は水素原子またはシクロアルキル基、アラルキル基、アルコキシ基、シクロアルコキシ基、アリールオキシ基、アラルキルオキシ基、アシル基、カルボニルオキシ基、オキシカルボニル基、オキシカルボニルオキシ基を表し、これらはさらに置換基を有していてよい。Ｒ21は水素原子またはアルキル基を表す。 In the formula, R 6 to R 20 represent a hydrogen atom or a cycloalkyl group, an aralkyl group, an alkoxy group, a cycloalkoxy group, an aryloxy group, an aralkyloxy group, an acyl group, a carbonyloxy group, an oxycarbonyl group, or an oxycarbonyloxy group. These may be further substituted. R 21 represents a hydrogen atom or an alkyl group.
　Ｒ6～Ｒ20のシクロアルキル基、アラルキル基、アルコキシ基、シクロアルコキシ基、アリールオキシ基、アラルキルオキシ基、アシル基、カルボニルオキシ基、オキシカルボニル基、オキシカルボニルオキシ基については、前記一般式（１）のＲ1～Ｒ5と同様の基が挙げられる。 The cycloalkyl group, aralkyl group, alkoxy group, cycloalkoxy group, aryloxy group, aralkyloxy group, acyl group, carbonyloxy group, oxycarbonyl group, and oxycarbonyloxy group of R 6 to R 20 are represented by the above general formula ( Examples thereof include the same groups as R 1 to R 5 in 1).
　以下に、本発明に係わる多価アルコールエステルの具体的化合物を例示する。 Hereinafter, specific compounds of polyhydric alcohol esters according to the present invention will be exemplified.
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000003
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000004
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000005
Figure JPOXMLDOC01-appb-C000006
Figure JPOXMLDOC01-appb-C000006
Figure JPOXMLDOC01-appb-C000007
Figure JPOXMLDOC01-appb-C000007
Figure JPOXMLDOC01-appb-C000008
Figure JPOXMLDOC01-appb-C000008
Figure JPOXMLDOC01-appb-C000009
Figure JPOXMLDOC01-appb-C000009
Figure JPOXMLDOC01-appb-C000010
Figure JPOXMLDOC01-appb-C000010
Figure JPOXMLDOC01-appb-C000011
Figure JPOXMLDOC01-appb-C000011
Figure JPOXMLDOC01-appb-C000012
Figure JPOXMLDOC01-appb-C000012
Figure JPOXMLDOC01-appb-C000013
Figure JPOXMLDOC01-appb-C000013
Figure JPOXMLDOC01-appb-C000014
Figure JPOXMLDOC01-appb-C000014
　（糖エステル可塑剤）
　本発明のセルロースエステルフィルムは、フラノース構造およびピラノース構造から選ばれる少なくとも一種の構造が１～１２個結合した糖化合物の水酸基をエステル化した糖エステル可塑剤を使用することも好ましい。 (Sugar ester plasticizer)
In the cellulose ester film of the present invention, it is also preferable to use a sugar ester plasticizer obtained by esterifying a hydroxyl group of a sugar compound in which 1 to 12 at least one structure selected from a furanose structure and a pyranose structure is bonded.
　本発明に用いられる糖エステル化合物としては、グルコース、ガラクトース、マンノース、フルクトース、キシロース、アラビノース、ラクトース、スクロース、セロビオース、セロトリオース、マルトトリオース、ラフィノースなどが挙げられるが、特にフラノース構造とピラノース構造を両方有するものが好ましい。例としてはスクロースが挙げられる。 Examples of the sugar ester compound used in the present invention include glucose, galactose, mannose, fructose, xylose, arabinose, lactose, sucrose, cellobiose, cellotriose, maltotriose, raffinose, etc., particularly both furanose structure and pyranose structure. What has is preferable. An example is sucrose.
　本発明に用いられる糖エステル可塑剤は、糖化合物の有する水酸基の一部または全部がエステル化されているものまたはその混合物である。 The sugar ester plasticizer used in the present invention is one in which part or all of the hydroxyl groups of the sugar compound are esterified or a mixture thereof.
Figure JPOXMLDOC01-appb-C000015
Figure JPOXMLDOC01-appb-C000015
Figure JPOXMLDOC01-appb-C000016
Figure JPOXMLDOC01-appb-C000016
Figure JPOXMLDOC01-appb-C000017
Figure JPOXMLDOC01-appb-C000017
Figure JPOXMLDOC01-appb-C000018
Figure JPOXMLDOC01-appb-C000018
Figure JPOXMLDOC01-appb-C000019
Figure JPOXMLDOC01-appb-C000019
Figure JPOXMLDOC01-appb-C000020
Figure JPOXMLDOC01-appb-C000020
Figure JPOXMLDOC01-appb-C000021
Figure JPOXMLDOC01-appb-C000021
Figure JPOXMLDOC01-appb-C000022
Figure JPOXMLDOC01-appb-C000022
　市販品としては、例えばモノペットＳＢ（第一工業製薬（株）製）等が挙げられる。 Examples of commercially available products include Monopet SB (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).
　（ポリマー可塑剤）
　本発明のセルロースエステルフィルムはポリマー可塑剤を使用することも好ましい。 (Polymer plasticizer)
The cellulose ester film of the present invention preferably uses a polymer plasticizer.
　その中でも特にアクリル系ポリマーが好ましい。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（例えば、共重合比１：９９～９９：１の間の任意の比率）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、メタクリル酸メチルとＮ－ビニルピロリドンの共重合体（例えば、共重合比１：９９～９９：１の間の任意の比率）、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、メタクリル酸メチルと４－ヒドロキシスチレンの共重合体（例えば、共重合比１：９９～９９：１の間の任意の比率）、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。 Of these, acrylic polymers are particularly preferred. Specifically, aliphatic hydrocarbon polymers, alicyclic hydrocarbon polymers, polyethyl acrylate, polymethyl methacrylate, copolymers of methyl methacrylate and 2-hydroxyethyl methacrylate (for example, copolymers) Acrylic polymers such as a polymerization ratio of 1:99 to 99: 1), vinyl polymers such as polyvinyl isobutyl ether and poly N-vinyl pyrrolidone, copolymers of methyl methacrylate and N-vinyl pyrrolidone ( For example, a copolymerization ratio of any ratio between 1:99 and 99: 1), a styrene polymer such as polystyrene and poly-4-hydroxystyrene, a copolymer of methyl methacrylate and 4-hydroxystyrene (eg, copolymerization) Any ratio between 1:99 and 99: 1), polybutylene succinate, polyethylene terephthalate, poly Polyesters such as Chi naphthalate, polyethylene oxide, polyether such as polyethylene oxide and polypropylene oxide, polyamides, polyurethanes, polyureas and the like.
　数平均分子量は１，０００～５００，０００程度が好ましく、特に好ましくは、５０００～２０００００である。１，０００以下では揮発性が大きくなり、５００，０００を超えると可塑化能力が低下する傾向があり、セルロースエステル光学フィルムの機械的性質に悪影響を及ぼす可能性がある。 The number average molecular weight is preferably about 1,000 to 500,000, particularly preferably 5000 to 200,000. If it is 1,000 or less, the volatility becomes large, and if it exceeds 500,000, the plasticizing ability tends to decrease, which may adversely affect the mechanical properties of the cellulose ester optical film.
　これらポリマー可塑剤は１種のモノマーの繰り返し単位からなる単独重合体でも、複数のモノマー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 homopolymers composed of repeating units of one kind of monomer or copolymers having a repeating structure of a plurality of monomers. Two or more of the above polymers may be used in combination.
　また表面の可塑剤量の測定法は特に限定されないが、例えば、ナイフなどを用いて、フィルムの表面から２０ｎｍほど削って定量分析する方法やフィルムの厚さ方向の可塑剤量をＩＲや原子吸光などでスキャンする方法などを用いて定量したものである。
〈酸化防止剤〉
　本発明では、酸化防止剤としては、通常知られているものを使用することができる。 Further, the method for measuring the amount of plasticizer on the surface is not particularly limited. For example, a knife or the like is used to quantitatively analyze the surface of the film by cutting it about 20 nm or the amount of plasticizer in the thickness direction of the film is measured by IR or atomic absorption. It is quantified using a method such as scanning with the above.
<Antioxidant>
In this invention, what is generally known can be used as an antioxidant.
　特に、ラクトン系、イオウ系、フェノール系、二重結合系、ヒンダードアミン系、リン系化合物のものを好ましく用いることができる。 In particular, lactone, sulfur, phenol, double bond, hindered amine and phosphorus compounds can be preferably used.
　例えば、チバ・ジャパン株式会社から、“ＩｒｇａｆｏｓＸＰ４０”、“ＩｒｇａｆｏｓＸＰ６０”という商品名で市販されているものを含むものが好ましい。 For example, those including those commercially available from Ciba Japan under the trade names “IrgafosXP40” and “IrgafosXP60” are preferable.
　上記フェノール系化合物としては、２，６－ジアルキルフェノールの構造を有するものが好ましく、例えば、チバ・ジャパン株式会社、“Ｉｒｇａｎｏｘ１０７６”、“Ｉｒｇａｎｏｘ１０１０”、（株）ＡＤＥＫＡ“アデカスタブＡＯ－５０”という商品名で市販されているものが好ましい。 The phenolic compound preferably has a 2,6-dialkylphenol structure. For example, trade names of Ciba Japan Co., Ltd., “Irganox 1076”, “Irganox 1010”, and ADEKA “ADEKA STAB AO-50” And those commercially available.
　上記リン系化合物は、例えば、住友化学株式会社から、“ＳｕｍｉｌｉｚｅｒＧＰ”（ＡＯ２）、株式会社ＡＤＥＫＡから“ＡＤＫ　ＳＴＡＢ　ＰＥＰ－２４Ｇ”、“ＡＤＫ　ＳＴＡＢ　ＰＥＰ－３６”（ＡＯ１）および“ＡＤＫ　ＳＴＡＢ　３０１０”、チバ・ジャパン株式会社から“ＩＲＧＡＦＯＳ　Ｐ－ＥＰＱ”（ＡＯ４）、堺化学工業株式会社から“ＧＳＹ－Ｐ１０１”（ＡＯ３）という商品名で市販されているものが好ましい。 The phosphorus compounds are, for example, from Sumitomo Chemical Co., Ltd., “Sumilizer GP” (AO2), from ADEKA Co., Ltd., “ADK STAB PEP-24G”, “ADK STAB PEP-36” (AO1) and “ADK STAB 3010”, Those commercially available under the trade name “IRGAFOS P-EPQ” (AO4) from Ciba Japan Co., Ltd. and “GSY-P101” (AO3) from Sakai Chemical Industry Co., Ltd. are preferred.
　上記ヒンダードアミン系化合物は、例えば、チバ・ジャパン株式会社から、“Ｔｉｎｕｖｉｎ１４４（ＡＯ２）”および“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ものが好ましい。 The above-mentioned hindered amine compounds are preferably commercially available from Ciba Japan Co., Ltd. under the trade names of “Tinuvin 144 (AO2)” and “Tinvin 770”, and from ADEKA Co., Ltd. as “ADK STAB LA-52”.
　上記イオウ系化合物は、例えば、住友化学株式会社から、“Ｓｕｍｉｌｉｚｅｒ　ＴＰＬ－Ｒ”および“Ｓｕｍｉｌｉｚｅｒ　ＴＰ－Ｄ”という商品名で市販されているものが好ましい。 The above sulfur compounds are preferably those commercially available from Sumitomo Chemical Co., Ltd. under the trade names “Sumilizer TPL-R” and “Sumilizer TP-D”.
　上記二重結合系化合物は、住友化学株式会社から、“Ｓｕｍｉｌｉｚｅｒ　ＧＭ”（ＡＯ５）および“Ｓｕｍｉｌｉｚｅｒ　ＧＳ”（ＡＯ３）という商品名で市販されているものが好ましい。 The above-mentioned double bond type compounds are preferably those commercially available from Sumitomo Chemical Co., Ltd. under the trade names “Sumilizer GM” (AO5) and “Sumilizer GS” (AO3).
　さらに、酸捕捉剤として米国特許第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を含有させることも可能である。 Furthermore, it is possible to contain a compound having an epoxy group as described in US Pat. No. 4,137,201 as an acid scavenger.
　これらの酸化防止剤等は、再生使用される際の工程に合わせて適宜添加する量が決められるが、一般には、フィルムの主原料である樹脂に対して、０．０５～２０質量％、好ましくは０．１～１質量％の範囲で添加される。 The amount of these antioxidants and the like to be added is appropriately determined in accordance with the process for recycling and use, but generally 0.05 to 20% by mass, preferably with respect to the resin as the main raw material of the film Is added in the range of 0.1 to 1% by 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、ラクトン系、リン系、フェノール系および二重結合系化合物の併用は好ましい。
〈レターデーション調整剤〉
　本発明のセルロースエステルフィルムにおいてレターデーションを調整するための化合物を含有させてもよい。 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 lactone, phosphorus, phenol and double bond compounds is preferred.
<Retardation adjuster>
The cellulose ester film of the present invention may contain a compound for adjusting the retardation.
　レターデーションを調整するために添加する化合物は、欧州特許第９１１，６５６Ａ２号明細書に記載されているような、二つ以上の芳香族環を有する芳香族化合物を使用することもできる。 As the compound to be added for adjusting the retardation, an aromatic compound having two or more aromatic rings as described in the specification of European Patent No. 911,656A2 can also be used.
　また２種類以上の芳香族化合物を併用してもよい。該芳香族化合物の芳香族環には、芳香族炭化水素環に加えて、芳香族性ヘテロ環を含む。芳香族性ヘテロ環であることが特に好ましく、芳香族性ヘテロ環は一般に不飽和ヘテロ環である。中でも１，３，５－トリアジン環を有する化合物が特に好ましい。
〈着色剤〉
　本発明においては、着色剤を使用することが好ましい。着色剤と言うのは染料や顔料を意味するが、本発明では、液晶画面の色調を青色調にする効果またはイエローインデックスの調整、ヘイズの低減を有するものを指す。 Two or more aromatic compounds may be used in combination. The aromatic ring of the aromatic compound includes an aromatic heterocyclic ring in addition to the aromatic hydrocarbon ring. An aromatic heterocyclic ring is particularly preferred, and the aromatic heterocyclic ring is generally an unsaturated heterocyclic ring. Of these, compounds having a 1,3,5-triazine ring are particularly preferred.
<Colorant>
In the present invention, it is preferable to use a colorant. The colorant means a dye or a pigment. In the present invention, the colorant means an effect of making the color tone of a liquid crystal screen blue, adjusting the yellow index, and reducing haze.
　着色剤としては各種の染料、顔料が使用可能だが、アントラキノン染料、アゾ染料、フタロシアニン顔料などが有効である。
〈紫外線吸収剤〉
　本発明に用いられる紫外線吸収剤は特に限定されないが、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、トリアジン系化合物、ニッケル錯塩系化合物、無機粉体等が挙げられる。高分子型の紫外線吸収剤としてもよい。
〈マット剤〉
　本発明では、フィルムの滑り性を付与するためにマット剤を添加することが好ましい。 Various dyes and pigments can be used as the colorant, but anthraquinone dyes, azo dyes, phthalocyanine pigments and the like are effective.
<Ultraviolet absorber>
Although the ultraviolet absorber used in the present invention is not particularly limited, for example, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, triazine compounds, nickel complex compounds, inorganic powders Examples include the body. It is good also as a polymer type ultraviolet absorber.
<Matting agent>
In the present invention, it is preferable to add a matting agent in order to impart film slipperiness.
　本発明で用いられるマット剤としては、得られるフィルムの透明性を損なうことがなく、溶融時の耐熱性があれば無機化合物または有機化合物どちらでもよく、例えば、タルク、マイカ、ゼオライト、ケイソウ土、焼成珪成土、カオリン、セリサイト、ベントナイト、スメクタイト、クレー、シリカ、石英粉末、ガラスビーズ、ガラス粉、ガラスフレーク、ミルドファイバー、ワラストナイト、窒化ホウ素、炭化ホウ素、ホウ化チタン、炭酸マグネシウム、重質炭酸カルシウム、軽質炭酸カルシウム、珪酸カルシウム、珪酸アルミニウム、珪酸マグネシウム、アルミノ珪酸マグネシウム、アルミナ、シリカ、酸化亜鉛、二酸化チタン、酸化鉄、酸化マグネシウム、酸化ジルコニウム、水酸化アルミニウム、水酸化カルシウム、水酸化マグネシウム、硫酸カルシウム、硫酸バリウム、炭化ケイ素、炭化アルミニウム、炭化チタン、窒化アルミニウム、窒化ケイ素、窒化チタン、ホワイトカーボンなどが挙げられる。 As the matting agent used in the present invention, any inorganic compound or organic compound may be used as long as it has heat resistance at the time of melting without impairing the transparency of the obtained film. For example, talc, mica, zeolite, diatomaceous earth, Calcined siliceous clay, kaolin, sericite, bentonite, smectite, clay, silica, quartz powder, glass beads, glass powder, glass flakes, milled fiber, wollastonite, boron nitride, boron carbide, titanium boride, magnesium carbonate, Heavy calcium carbonate, light calcium carbonate, calcium silicate, aluminum silicate, magnesium silicate, magnesium aluminosilicate, alumina, silica, zinc oxide, titanium dioxide, iron oxide, magnesium oxide, zirconium oxide, aluminum hydroxide, calcium hydroxide, water Magne oxide Um, calcium sulfate, barium sulfate, silicon carbide, aluminum carbide, titanium carbide, aluminum nitride, silicon nitride, titanium nitride, and white carbon.
　これらのマット剤は、単独でも二種以上併用しても使用できる。粒径や形状（例えば針状と球状など）の異なる粒子を併用することで高度に透明性と滑り性を両立させることもできる。 These matting agents can be used alone or in combination of two or more. By using particles having different particle sizes and shapes (for example, acicular and spherical), both transparency and slipperiness can be made highly compatible.
　これらの中でも、セルロースエステルと屈折率が近いので透明性（ヘイズ）に優れる二酸化珪素が特に好ましく用いられる。二酸化珪素の具体例としては、アエロジル２００Ｖ、アエロジルＲ９７２Ｖ、アエロジルＲ９７２、Ｒ９７４、Ｒ８１２、２００、３００、Ｒ２０２、ＯＸ５０、ＴＴ６００（以上日本アエロジル（株）製）、シーホスターＫＥＰ－１０、シーホスターＫＥＰ－３０、シーホスターＫＥＰ－５０（以上、株式会社日本触媒製）、サイロホービック１００（富士シリシア製）、ニップシールＥ２２０Ａ（日本シリカ工業製）、アドマファインＳＯ（アドマテックス製）等の商品名を有する市販品などが好ましく使用できる。 Of these, silicon dioxide is particularly preferably used since it has a refractive index close to that of cellulose ester and is excellent in transparency (haze). Specific examples of silicon dioxide include Aerosil 200V, Aerosil R972V, Aerosil R972, R974, R812, 200, 300, R202, OX50, TT600 (above Nippon Aerosil Co., Ltd.), Seahoster KEP-10, Seahoster KEP-30, Commercial products with trade names such as Seahoster KEP-50 (above, Nippon Shokubai Co., Ltd.), Silo Hovic 100 (Fuji Silysia), Nip Seal E220A (Nihon Silica Kogyo), Admafine SO (Admatechs), etc. Can be preferably used.
　粒子の形状としては、不定形、針状、扁平、球状等特に制限なく使用できるが、特に球状の粒子を用いると得られるフィルムの透明性が良好にできるので好ましい。粒子の大きさは、可視光の波長に近いと光が散乱し、透明性が悪くなるので、可視光の波長より小さいことが好ましく、さらに可視光の波長の１／２以下であることが好ましい。 The shape of the particles can be used without particular limitation, such as indefinite shape, needle shape, flat shape, spherical shape, etc. However, the use of spherical particles is preferable because the transparency of the resulting film can be improved. When the particle size is close to the wavelength of visible light, light is scattered and the transparency is deteriorated. Therefore, the particle size is preferably smaller than the wavelength of visible light, and more preferably ½ or less of the wavelength of visible light. .
　粒子の大きさが小さすぎると滑り性が改善されない場合があるので、８０ｎｍから１８０ｎｍの範囲であることが特に好ましい。 ∙ If the particle size is too small, the slipperiness may not be improved, so the range of 80 nm to 180 nm is particularly preferable.
　なお、粒子の大きさとは、粒子が１次粒子の凝集体の場合は凝集体の大きさを意味する。また、粒子が球状でない場合は、その投影面積に相当する円の直径を意味する。
〈粘度低下剤〉
　本発明において、溶融粘度を低減する目的として、水素結合性溶媒を添加することができる。水素結合性溶媒とは、Ｊ．Ｎ．イスラエルアチビリ著、「分子間力と表面力」（近藤保、大島広行訳、マグロウヒル出版、１９９１年）に記載されるように、電気的に陰性な原子（酸素、窒素、フッ素、塩素）と電気的に陰性な原子と共有結合した水素原子間に生ずる、水素原子媒介「結合」を生ずることができるような有機溶媒、すなわち、結合モーメントが大きく、かつ水素を含む結合、例えば、Ｏ－Ｈ（酸素水素結合）、Ｎ－Ｈ（窒素水素結合）、Ｆ－Ｈ（フッ素水素結合）を含むことで近接した分子同士が配列できるような有機溶媒をいう。 The particle size means the size of the aggregate when the particle is an aggregate of primary particles. Moreover, when a particle is not spherical, it means the diameter of a circle corresponding to the projected area.
<Viscosity reducing agent>
In the present invention, a hydrogen bonding solvent can be added for the purpose of reducing the melt viscosity. The hydrogen bonding solvent is J.I. N. As described in Israel Ativili, “Intermolecular Forces and Surface Forces” (Takeshi Kondo, Hiroyuki Oshima, Maglow Hill Publishing, 1991) and electrically negative atoms (oxygen, nitrogen, fluorine, chlorine) An organic solvent capable of producing a hydrogen atom-mediated “bond” that occurs between an electronegative atom and a covalently bonded hydrogen atom, that is, a bond having a large bonding moment and containing hydrogen, such as OH (Oxygen hydrogen bond), N—H (nitrogen hydrogen bond), FH (fluorine hydrogen bond), and an organic solvent that can arrange adjacent molecules.
　これらは、セルロース樹脂の分子間水素結合よりもセルロースとの間で強い水素結合を形成する能力を有するもので、本発明で行う溶融流延法においては、用いるセルロース樹脂単独のガラス転移温度よりも、水素結合性溶媒の添加によりセルロース樹脂組成物の溶融温度を低下することができる。 These have the ability to form stronger hydrogen bonds with cellulose than intermolecular hydrogen bonds of cellulose resin. In the melt casting method performed in the present invention, the glass transition temperature of the cellulose resin used alone is higher than that. The melting temperature of the cellulose resin composition can be lowered by adding a hydrogen bonding solvent.
　または同じ溶融温度においてセルロース樹脂よりも水素結合性溶媒を含むセルロース樹脂組成物の溶融粘度を低下することができる。 Alternatively, the melt viscosity of the cellulose resin composition containing a hydrogen bonding solvent can be lowered than that of the cellulose resin at the same melting temperature.
　水素結合性溶媒としては、例えば、アルコール類：例えば、メタノール、エタノール、プロパノール、イソプロパノール、ｎ－ブタノール、ｓｅｃ－ブタノール、ｔ－ブタノール、２－エチルヘキサノール、ヘプタノール、オクタノール、ノナノール、ドデカノール、エチレングリコール、プロピレングリコール、ヘキシレングリコール、ジプロピレングリコール、ポリエチレングリコール、ポリプロピレングリコール、メチルセロソルブ、エチルセロソルブ、ブチルセロソルブ、ヘキシルセロソルブ、グリセリン等、ケトン類：アセトン、メチルエチルケトン等、カルボン酸類：例えば蟻酸、酢酸、プロピオン酸、酪酸等、エーテル類：例えば、ジエチルエーテル、テトラヒドロフラン、ジオキサン等、ピロリドン類：例えば、Ｎ－メチルピロリドン等、アミン類：例えば、トリメチルアミン、ピリジン等、等を例示することができる。 Examples of the hydrogen bonding solvent include alcohols such as methanol, ethanol, propanol, isopropanol, n-butanol, sec-butanol, t-butanol, 2-ethylhexanol, heptanol, octanol, nonanol, dodecanol, ethylene glycol, Propylene glycol, hexylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, hexyl cellosolve, glycerin, etc., ketones: acetone, methyl ethyl ketone, etc., carboxylic acids: eg formic acid, acetic acid, propionic acid, Butyric acid, etc., ethers: eg, diethyl ether, tetrahydrofuran, dioxane, etc., Pyrrolidones: eg, N-methyl Pyrrolidone, amines: for example, can be exemplified trimethylamine, pyridine, etc., and the like.
　これら水素結合性溶媒は、単独で、または２種以上混合して用いることができる。これらのうちでも、アルコール、ケトン、エーテル類が好ましく、特にメタノール、エタノール、プロパノール、イソプロパノール、オクタノール、ドデカノール、エチレングリコール、グリセリン、アセトン、テトラヒドロフランが好ましい。 These hydrogen bonding solvents can be used alone or in admixture of two or more. Among these, alcohol, ketone, and ether are preferable, and methanol, ethanol, propanol, isopropanol, octanol, dodecanol, ethylene glycol, glycerin, acetone, and tetrahydrofuran are particularly preferable.
　さらに、メタノール、エタノール、プロパノール、イソプロパノール、エチレングリコール、グリセリン、アセトン、テトラヒドロフランのような水溶性溶媒が特に好ましい。ここで水溶性とは、水１００ｇに対する溶解度が１０ｇ以上のものをいう。 Furthermore, water-soluble solvents such as methanol, ethanol, propanol, isopropanol, ethylene glycol, glycerin, acetone, and tetrahydrofuran are particularly preferable. Here, water-soluble means that the solubility in 100 g of water is 10 g or more.
　これらの溶媒は、溶融製膜時に揮発し、最終的には含有溶媒量として０．０１質量％以下とされる。
＜溶融流延製膜法＞
　本発明における溶融流延製膜とは、セルロースエステルおよび可塑剤などの添加剤を含む組成物を、流動性を示す温度まで加熱溶融し、その後、流動性のセルロースエステルを含む溶融物を流延することを溶融製膜として定義する。 These solvents are volatilized at the time of melt film formation, and finally the content of the solvent is 0.01% by mass or less.
<Melt casting method>
The melt casting film formation in the present invention is a method in which a composition containing additives such as cellulose ester and a plasticizer is heated and melted to a temperature showing fluidity, and then a melt containing fluid cellulose ester is cast. This is defined as melt film formation.
　加熱溶融する成形法は、さらに詳細には、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、機械的強度および表面精度などに優れるセルロースエステルフィルムを得るためには、溶融押し出し法が優れている。
〈製膜方法〉
　以下、フィルムの製膜方法について説明する。 More specifically, the heat melting molding method 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, in order to obtain a cellulose ester film excellent in mechanical strength and surface accuracy, the melt extrusion method is excellent.
<Film forming method>
Hereinafter, the film forming method will be described.
　（セルロースエステルと添加剤の溶融ペレット製造工程）
　溶融押出に用いる複数の原材料は、通常あらかじめ混錬してペレット化しておくことが好ましい。 (Process for producing molten pellets of cellulose ester and additives)
It is preferable that a plurality of raw materials used for melt extrusion are usually kneaded and pelletized in advance.
　ペレット化は、公知の方法でよく、例えば、乾燥セルロースエステルや可塑剤、その他添加剤をフィーダーで押出機に供給し１軸や二軸の押出機を用いて混錬し、ダイからストランド状に押し出し、水冷または空冷し、カッティングすることでできる。 Pelletization may be performed by a known method. For example, dry cellulose ester, plasticizer, and other additives are fed to an extruder using a feeder and kneaded using a single-screw or twin-screw extruder, and then formed into a strand from a die. It can be done by extrusion, water cooling or air cooling and cutting.
　原材料は、押出する前に乾燥しておくことが原材料の分解を防止する上で重要である。特にセルロースエステルは吸湿しやすいので、除湿熱風乾燥機や真空乾燥機で７０～１４０℃で３時間以上乾燥し、水分率を２００ｐｐｍ以下、さらに１００ｐｐｍ以下にしておくことが好ましい。 It is important to dry the raw material before extruding to prevent the raw material from being decomposed. In particular, since cellulose ester easily absorbs moisture, it is preferable to dry it at 70 to 140 ° C. for 3 hours or more with a dehumidifying hot air dryer or a vacuum dryer so that the moisture content is 200 ppm or less, and further 100 ppm or less.
　添加剤は、押出機に供給する前に混合しておいてもよいし、それぞれ個別のフィーダーで供給してもよい。酸化防止剤等少量の添加剤さらに均一に混合するため、事前に混合しておくことが好ましい。 Additives may be mixed before being supplied to the extruder, or may be supplied by individual feeders. A small amount of additives such as antioxidants are preferably mixed in advance in order to mix more uniformly.
　酸化防止剤の混合は、固体同士で混合してもよいし、必要により、酸化防止剤を溶剤に溶解しておき、セルロースエステルに含浸させて混合してもよく、あるいは噴霧して混合してもよい。 Mixing of the antioxidants may be performed by mixing solids, and if necessary, the antioxidant may be dissolved in a solvent, impregnated with cellulose ester and mixed, or sprayed and mixed. Also good.
　真空ナウターミキサーなどが乾燥と混合を同時にできるので好ましい。また、フィーダー部やダイからの出口など空気と触れる場合は、除湿空気や除湿したＮ2ガスなどの雰囲気下にすることが好ましい。 A vacuum nauter mixer or the like is preferable because drying and mixing can be performed simultaneously. Further, if the contact with air, such as the exit from the feeder unit or die, it is preferable that the atmosphere such as dehumidified air and dehumidified N 2 gas.
　また、押出機への供給ホッパー等は保温しておくことが吸湿防止できるので好ましい。 In addition, it is preferable to keep the supply hopper and the like to the extruder warm because moisture absorption can be prevented.
　マット剤やＵＶ吸収剤などは、得られたペレットにまぶしたり、フィルム製膜時に押出機中で添加したりしてもよい。 Matting agents, UV absorbers, and the like may be applied to the obtained pellets or added in an extruder during film formation.
　押出機は、せん断力を抑え、樹脂が劣化（分子量低下、着色、ゲル生成等）しないようにペレット化可能でなるべく低温で加工することが好ましい。例えば、二軸押出機の場合、深溝タイプのスクリューを用いて、同方向に回転させることが好ましい。混錬の均一性から、噛み合いタイプが好ましい。 The extruder is preferably processed at as low a temperature as possible so as to be able to be pelletized so that the shear force is suppressed and the resin does not deteriorate (molecular weight reduction, coloring, gel formation, etc.). For example, in the case of a twin screw extruder, it is preferable to rotate in the same direction using a deep groove type screw. From the uniformity of kneading, the meshing type is preferable.
　ニーダーディスクは、混錬性を向上できるが、せん断発熱に注意が必要である。ニーダーディスクを用いなくても混合性は十分である。ベント孔からの吸引は必要に応じて行えばよい。低温であれば揮発成分はほとんど発生しないのでベント孔なしでもよい。 ¡Kneader discs can improve kneadability, but care must be taken against shearing heat generation. Mixability is sufficient without using a kneader disk. The suction from the vent hole may be performed as necessary. Since there is almost no volatile component at low temperatures, there may be no vent hole.
　ペレットの色は、黄味の指標であるｂ＊値が－５～１０の範囲にあることが好ましく、－１～８の範囲にあることがさらに好ましく、－１～５の範囲にあることがより好ましい。 As for the color of the pellet, the b * value as an index of yellowness is preferably in the range of -5 to 10, more preferably in the range of -1 to 8, and preferably in the range of -1 to 5. More preferred.
　ｂ＊値は分光測色計ＣＭ－３７００ｄ（コニカミノルタセンシング（株）製）で、光源をＤ６５（色温度６５０４Ｋ）とし、視野角１０°で測定することができる。 B * value can be measured with a spectrophotometer CM-3700d (manufactured by Konica Minolta Sensing Co., Ltd.) with a light source of D65 (color temperature 6504K) and a viewing angle of 10 °.
　以上のようにして得られたペレットを用いてフィルム製膜を行う。もちろんペレット化せず、原材料の粉末をそのままフィーダーで押出機に供給し、そのままフィルム製膜することも可能である。 Film formation is performed using the pellets obtained as described above. Of course, the raw material powder can be directly fed to the extruder by a feeder without being pelletized to form a film as it is.
　（セルロースエステルと添加剤の溶融物をダイから押し出す工程）
　除湿熱風や真空または減圧下で乾燥したポリマーを１軸や二軸タイプの押出し機を用いて、押し出す際の溶融温度を２００～３００℃程度とし、リーフディスクタイプのフィルターなどで濾過し異物を除去したあと、Ｔダイからフィルム状に流延し、冷却ロール上で固化させる。 (Process of extruding a melt of cellulose ester and additive from the die)
Dehydrated hot air or polymer dried under vacuum or reduced pressure using a single or twin screw type extruder with a melting temperature of about 200-300 ° C and filtered through a leaf disk type filter to remove foreign matter Then, it is cast into a film from a T die and solidified on a cooling roll.
　供給ホッパーから押出し機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 from the supply hopper to the extruder, it is preferable to prevent oxidative decomposition or the like under vacuum or reduced pressure or in an inert gas atmosphere.
　押し出し流量は、ギヤポンプを導入するなどして安定に行うことが好ましい。また、異物の除去に用いるフィルターは、ステンレス繊維焼結フィルターが好ましく用いられる。 The extrusion flow rate is preferably performed stably by introducing a gear pump. Further, a stainless fiber sintered filter is preferably used as a filter used for removing foreign substances.
　ステンレス繊維焼結フィルターは、ステンレス繊維体を複雑に絡み合った状態を作り出した上で圧縮し接触箇所を焼結し一体化したもので、その繊維の太さと圧縮量により密度を変え、濾過精度を調整できる。 The stainless steel fiber sintered filter is a united stainless steel fiber body that is intricately intertwined and compressed, and the contact points are sintered and integrated. The density of the fiber is changed depending on the thickness of the fiber and the amount of compression, and the filtration accuracy is improved. Can be adjusted.
　濾過精度を粗、密と連続的に複数回繰り返した多層体としたものが好ましい。また、濾過精度を順次上げていく構成としたり、濾過精度の粗、密を繰り返す方法をとることで、フィルターの濾過寿命が延び、異物やゲルなどの補足精度も向上できるので好ましい。 It is preferable to use a multilayer body in which the filtration accuracy is repeated coarsely and densely multiple times. Further, it is preferable to adopt a configuration in which the filtration accuracy is sequentially increased or a method in which coarse and dense filtration accuracy is repeated, so that the filtration life of the filter can be extended and the accuracy of capturing foreign matters and gels can be improved.
　ダイに傷や異物が付着するとスジ状の欠陥が発生する場合がある。このような欠陥をダイラインとも呼ぶが、ダイライン等の表面の欠陥を小さくするためには、押出機からダイまでの配管には樹脂の滞留部が極力少なくなるような構造にすることが好ましい。ダイの内部やリップにキズ等が極力ないものを用いることが好ましい。 ∙ If flaws or foreign matter adhere to the die, streaky defects may occur. Such defects are also referred to as die lines, but in order to reduce surface defects such as die lines, it is preferable that the piping from the extruder to the die has a structure in which the resin retention portion is minimized. It is preferable to use a die that has as few scratches as possible inside the lip.
　押出機やダイなどの溶融樹脂と接触する内面は、表面粗さを小さくしたり、表面エネルギーの低い材質を用いるなどして、溶融樹脂が付着し難い表面加工が施されていることが好ましい。具体的には、ハードクロムメッキやセラミック溶射したものを表面粗さ０．２Ｓ以下となるように研磨したものが挙げられる。 The inner surface that comes into contact with the molten resin, such as an extruder or a die, is preferably subjected to surface treatment that makes it difficult for the molten resin to adhere to the surface by reducing the surface roughness or using a material with low surface energy. Specifically, a hard chrome plated or ceramic sprayed material is polished so that the surface roughness is 0.2 S or less.
　可塑剤などの添加剤は、あらかじめ樹脂と混合しておいてもよいし、押出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などの混合装置を用いることが好ましい。 Additives such as plasticizers may be mixed with the resin in advance or 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.
　（ダイから押し出された溶融物を冷却ロールと弾性タッチロールとの間に押圧しながら流延する工程）
　冷却ロールと弾性タッチロールでフィルムをニップする際のタッチロール側のフィルム温度はフィルムのＴｇ以上Ｔｇ＋１１０℃以下にすることが好ましい。このような目的で使用する弾性体表面を有するロールは、公知のロールが使用できる。 (Process of casting while pressing the melt extruded from the die between the cooling roll and the elastic touch roll)
The film temperature on the touch roll side when the film is nipped between the cooling roll and the elastic touch roll is preferably Tg or more and Tg + 110 ° C. or less of the film. A well-known roll can be used for the roll which has the elastic body surface used for such a purpose.
　冷却ロールからフィルムを剥離する際は、張力を制御してフィルムの変形を防止することが好ましい。 When peeling the film from the cooling roll, it is preferable to control the tension to prevent deformation of the film.
　（延伸工程）
　本発明では、上記のようにして得られたフィルムは冷却ロールに接する工程を通過後、フィルムをフィルム製膜方向に下記式（１）で表される延伸速度が１０００％／ｍｉｎ～３００００％／ｍｉｎで延伸することが、フィルムの音速を所望の音速に制御する上で好ましい方法である。 (Stretching process)
In the present invention, the film obtained as described above passes through the step of contacting the cooling roll, and then the film is stretched at a stretching speed represented by the following formula (1) in the film forming direction of 1000% / min to 30000% / Stretching at min is a preferable method for controlling the sound speed of the film to a desired sound speed.
　延伸に要する時間は延伸工程の距離とフィルム搬送速度から算出し、延伸後寸法は延伸前に決まった長さでしるしをつけておき、延伸後の長さを測定することで求めた。 The time required for stretching was calculated from the distance of the stretching process and the film conveyance speed, and the dimension after stretching was obtained by marking the length after stretching with a mark determined before stretching.
　式（１）
　延伸速度（％／ｍｉｎ）＝｛（延伸後寸法／延伸前寸法）－１｝×１００（％）／延伸に要する時間（ｍｉｎ）
　さらに、前記フィルムの幅手方向に前記式（１）で表される延伸速度が４００％／ｍｉｎ～１５００％／ｍｉｎで延伸すること、前記フィルムを少なくとも製膜方向か幅手方向のどちらか一方に５０％～２００％延伸することが好ましい。 Formula (1)
Stretching speed (% / min) = {(dimension after stretching / dimension before stretching) -1} × 100 (%) / time required for stretching (min)
Further, the film is stretched in the width direction of the film at a stretching speed represented by the formula (1) of 400% / min to 1500% / min, and the film is at least one of the film forming direction and the width direction. It is preferable to stretch 50% to 200%.
　延伸倍率が小さすぎると、好ましい音速値をもつセルロースエステルフィルムを得ることが困さらになり、逆に大きすぎると、フィルムが破断してしまったり、自重に耐え切れず、フィルムがたるんでしまう。 If the draw ratio is too small, it is difficult to obtain a cellulose ester film having a preferable sound velocity value. On the other hand, if the stretch ratio is too large, the film may be broken or the film may not be able to withstand its own weight, and the film will sag.
　延伸する方法は、公知のロール延伸機やテンターなどを好ましく用いることができる。 As the stretching method, a known roll stretching machine or tenter can be preferably used.
　延伸温度は、通常フィルムを構成する樹脂のＴｇ～Ｔｇ＋６０℃の温度範囲で行われることが好ましい。 The stretching temperature is preferably performed in the temperature range of Tg to Tg + 60 ° C. of the resin constituting the film.
　フィルム構成材料のガラス転移温度Ｔｇはフィルムを構成する材料種およ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。光学フィルムを作製する場合、Ｔｇは１１０℃以上、好ましくは１２５℃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 film constituting material can be controlled by making the material type constituting the film and the ratio of the constituting material different. When producing an optical film, Tg is 110 ° C. or higher, preferably 125 ° 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レターデーション値およ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 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.
　フィルムのＴｇが高過ぎると、フィルム構成材料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 film is too high, the temperature is increased when the film constituent material is made into a film, so that the energy consumption for heating is increased, and the material itself may be decomposed when it is made into a film, resulting in coloring. Therefore, Tg is preferably 250 ° C. or lower.
　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.
　延伸温度が低すぎると破断してしまう場合があり、高すぎると所望のレターデーションが得られない場合がある。 If the stretching temperature is too low, it may break, and if it is too high, the desired retardation may not be obtained.
　延伸は、幅手方向で制御された均一な温度分布下で行うことが好ましい。好ましくは±２℃以内、さらに好ましくは±１℃以内、特に好ましくは±０．５℃以内である。 The stretching is preferably performed under a uniform temperature distribution controlled in the width direction. The temperature is preferably within ± 2 ° C, more preferably within ± 1 ° C, and particularly preferably within ± 0.5 ° C.
　巻き取る前に、製品となる幅に端部をスリットして裁ち落とし、巻き中の貼り付きやすり傷防止のために、ナール加工（エンボッシング加工）を両端に施してもよい。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。 Before winding, the end may be slit and trimmed to the product width, and knurled (embossed) may be applied to both ends to prevent sticking and scratching during winding. The knurling method can process a metal ring having an uneven pattern on its side surface by heating or pressing.
　なお、フィルム両端部のクリップの把持部分は通常、フィルムが変形しており製品として使用できないので切除されて、再利用される。 Note that the clip grips at both ends of the film are usually cut out and reused because the film is deformed and cannot be used as a product.
　以下、その延伸方法について説明する。 Hereinafter, the stretching method will be described.
　延伸は製膜方向（ＭＤ）の延伸（縦延伸）、幅手方向（ＴＤ）の延伸（横延伸）、およびこれらの組み合わせによって実施される。縦延伸は、ロール延伸（出口側の周速を速くした２対以上のニップロールを用いて製膜方向に延伸）や固定端延伸（フィルムの両端を把持しこれを製膜方向に次第に早く搬送して製膜方向に延伸）等により行うことができる。 Stretching is performed by stretching in the film forming direction (MD) (longitudinal stretching), stretching in the width direction (TD) (transverse stretching), and combinations thereof. Longitudinal stretching includes roll stretching (stretching in the film forming direction using two or more pairs of nip rolls with increased peripheral speed on the outlet side) and fixed end stretching (gripping both ends of the film and transporting it gradually in the film forming direction. For example, stretching in the film forming direction).
　また横延伸は、テンター延伸｛フィルムの両端をチャックで把持しこれを横方向（製膜方向と直角方向）に広げて延伸｝等により行うことができる。 Further, the transverse stretching can be performed by tenter stretching (holding both ends of the film with a chuck and stretching the film in the transverse direction (perpendicular to the film forming direction)) or the like.
　本発明において延伸倍率としては、少なくとも一方に１％～２５０％、より好ましくは２％～２００％、さらに好ましくは３％～１５０％である。縦、横均等に延伸してもよいが、一方の延伸倍率を他方より大きくし不均等に延伸するほうがより好ましい。 In the present invention, the draw ratio is at least 1% to 250%, more preferably 2% to 200%, and still more preferably 3% to 150%. Although it may be stretched evenly in the vertical and horizontal directions, it is more preferable to stretch one of the stretch ratios more than the other and stretch the same.
　縦（ＭＤ）、横（ＴＤ）いずれを大きくしてもよいが、小さい方の延伸倍率は０％～３０％が好ましく、より好ましくは０％～２５％であり、さらに好ましくは０％～２０％である。大きいほうの延伸倍率は１％～２５０％であり、より好ましくは１０％～２００％、さらに好ましくは３０％～１５０％である。 Either longitudinal (MD) or lateral (TD) may be increased, but the smaller draw ratio is preferably 0% to 30%, more preferably 0% to 25%, and still more preferably 0% to 20%. %. The larger draw ratio is 1% to 250%, more preferably 10% to 200%, and still more preferably 30% to 150%.
　　延伸倍率（％）＝１００×｛（延伸後の長さ）－（延伸前の長さ）｝／（延伸前の長さ）
　これらの縦延伸と横延伸は、それぞれ単独で行ってもよく（一軸延伸）、組み合わせて行ってもよい（二軸延伸）。二軸延伸の場合、縦、横逐次で実施してもよく（逐次延伸）、同時に実施してもよい（同時延伸）。 Stretch ratio (%) = 100 × {(Length after stretching) − (Length before stretching)} / (Length before stretching)
These longitudinal stretching and lateral stretching may be performed independently (uniaxial stretching) or may be performed in combination (biaxial stretching). In the case of biaxial stretching, it may be carried out in the longitudinal and transverse sequential manners (sequential stretching) or simultaneously (simultaneous stretching).
　製膜方向の延伸の延伸速度は、１０００％／ｍｉｎ～３００００％／ｍｉｎが好ましく、より好ましくは５０００％／ｍｉｎ～２００００％／ｍｉｎ、さらに好ましくは１００００％／分～２００００％／ｍｉｎである。多段延伸の場合、延伸速度は各段の延伸速度の平均値を指す。 The stretching speed of stretching in the film forming direction is preferably 1000% / min to 30000% / min, more preferably 5000% / min to 20000% / min, and further preferably 10,000% / min to 20000% / min. In the case of multistage stretching, the stretching speed refers to the average value of the stretching speed of each stage.
　さらに、前記フィルムの幅手方向へ前記式（１）さらにされる延伸速度が４００％／ｍｉｎ～１５００％／ｍｉｎで延伸することが好ましい。より好ましくは５００％／ｍｉｎ～１４００％／ｍｉｎ、さらに好ましくは６００％／分～１３００％／ｍｉｎである。 Furthermore, it is preferable that the film is stretched in the width direction of the film at a stretching speed of 400% / min to 1500% / min. More preferably, it is 500% / min to 1400% / min, and further preferably 600% / min to 1300% / min.
　このような延伸に引き続き、縦または横方向に０％～１０％緩和することが好ましい。さらに、延伸に引き続き、１５０℃～２５０℃で１秒～３分熱固定することも好ましい。 Following such stretching, it is preferable to relax by 0% to 10% in the vertical or horizontal direction. Furthermore, it is preferable to heat-fix at 150 to 250 ° C. for 1 second to 3 minutes following the stretching.
　ここで、Ｒｏとは面内レターデーションを示し、面内の製膜方向ＭＤの屈折率と幅手方向ＴＤの屈折率との差に厚みを乗じたもの、Ｒｔとは厚み方向レターデーションを示し、面内の屈折率（製膜方向ＭＤと幅方向ＴＤの平均）と厚み方向の屈折率との差に厚みを乗じたものである。 Here, Ro indicates in-plane retardation, the difference between the refractive index in the in-plane film forming direction MD and the refractive index in the width direction TD is multiplied by the thickness, and Rt indicates the thickness direction retardation. The difference between the in-plane refractive index (average of the film forming direction MD and the width direction TD) and the refractive index in the thickness direction is multiplied by the thickness.
　延伸は、例えばフィルムの製膜方向および幅手方向に対して、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 with respect to, for example, the film forming direction and the width direction of the film. 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 film breakage may occur.
　互いに直交する二軸方向に延伸することは、フィルムの屈折率ｎｘ、ｎｙ、ｎｚを所定の範囲に入れるために有効な方法である。 Stretching in biaxial directions perpendicular to each other is an effective method for putting the refractive indexes nx, ny, and nz of the film within a predetermined range.
　ここで、ｎｘとはフィルムＭＤ方向の屈折率、ｎｙとはＴＤ方向の屈折率、ｎｚとは厚み方向の屈折率である。 Here, nx is the refractive index in the film MD direction, ny is the refractive index in the TD direction, and nz is the refractive index in the thickness direction.
　例えばフィルム製膜方向に延伸した場合、幅手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、フィルムの幅収縮を抑制、あるいは幅手方向にも延伸することで改善できる。幅手方向に延伸する場合、幅手方向で屈折率に分布が生じることがある。 For example, when the film is stretched in the film forming 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 film can be suppressed or improved by stretching in the width direction. When stretching in the width direction, the refractive index may be distributed in the width direction.
　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、フィルムを幅手方向に延伸したことで、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。 This distribution may appear when the tenter method is used, and by stretching the film in the width direction, a shrinkage force is generated in the center of the film, and the phenomenon is caused by the end being fixed, It is thought to be a so-called Boeing phenomenon.
　この場合でも、フィルム製膜方向に延伸することで、ボーイング現象を抑制でき、幅手方向の位相差の分布を少なくできる。 Even in this case, by stretching in the film forming direction, the bowing phenomenon can be suppressed and the distribution of retardation in the width direction can be reduced.
　互いに直交する二軸方向に延伸することにより、得られるフィルムの膜厚変動が減少できる。膜厚変動が大き過ぎると位相差のムラとなり、液晶ディスプレイに用いたとき着色等のむらが問題となることがある。 The film thickness fluctuation of the obtained film can be reduced by stretching in biaxial directions perpendicular to each other. If the film thickness variation is too large, the phase difference becomes uneven, and unevenness such as coloring may be a problem when used in a liquid crystal display.
　本発明のセルロースエステルフィルムの膜厚変動は、±３％、さらに±１％の範囲とすることが好ましい。 The film thickness variation of the cellulose ester film of the present invention is preferably in the range of ± 3%, more preferably ± 1%.
　延伸後、フィルムの端部をスリッターにより製品となる幅にスリットして裁ち落としたあと、エンボスリングおよびバックロール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、巻取り機によって巻き取ることにより、セルロースエステルフィルム（元巻き）の貼り付きや、すり傷の発生を防止する。 After stretching, after slitting the end of the film to a product width with a slitter, the film is subjected to knurling (embossing) on both ends of the film by a knurling device consisting of an embossing ring and a back roll, and a winder By taking up with, it prevents the cellulose ester film (original winding) from sticking and the generation of scratches.
　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。 The knurling method can process a metal ring having an uneven pattern on its side surface by heating or pressing.
　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。 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 excised and reused as a raw material.
　一般的に、溶融押し出しでは流延ダイの形状により、端部側の滞留時間が長くなる傾向が知られており、それによりフィルム端部の着色が促進されると考えられる。本発明では溶融押し出し直後のフィルム幅手方向の端部のイエローインデックスＹｅと、フィルム中央部分のイエローインデックスＹｃは下式を満たすことが好ましく、より好ましくはＹｅ／Ｙｃが３．０以下である。 In general, it is known that the melt-extrusion tends to increase the residence time on the side of the end due to the shape of the casting die, thereby promoting the coloring of the end of the film. In the present invention, the yellow index Ye at the end in the width direction of the film immediately after melt extrusion and the yellow index Yc at the center of the film preferably satisfy the following formula, and more preferably, Ye / Yc is 3.0 or less.
　Ｙｅ／Ｙｃが５．０より大きいと、フィルム端部を切除して、原料として再利用した際に、生産したフィルムの着色が増加する。なお、本発明で端部のイエローインデックスとはフィルム幅手方向の両端部から３０ｍｍ以内での最大値と定義する。 If Ye / Yc is greater than 5.0, the color of the produced film increases when the film edge is cut off and reused as a raw material. In the present invention, the yellow index at the end is defined as the maximum value within 30 mm from both ends in the width direction of the film.
　式　１．０≦Ｙｅ／Ｙｃ≦５．０
　光学フィルムの場合、該フィルムの厚さは、１０～５００μｍが好ましい。特に、下限は２０μｍ以上、好ましくは３０μｍ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２５以上～９０μｍである。 Formula 1.0 ≦ Ye / Yc ≦ 5.0
In the case of an optical film, the thickness of the film is preferably 10 to 500 μm. In particular, the lower limit is 20 μm or more, preferably 30 μm or more. The upper limit is 150 μm or less, preferably 120 μm or less. A particularly preferred range is 25 to 90 μm.
　フィルムが厚いと、偏光板加工後の偏光板が厚くなり過ぎ、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においては、特に薄型軽量の目的に適さなくなる。一方、フィルムが薄いと、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する傾向がある。 If the film is thick, the polarizing plate after polarizing plate processing becomes too thick, so that it is not suitable for the purpose of thin and light in liquid crystal displays used for notebook computers and mobile electronic devices. On the other hand, if the film is thin, the moisture permeability of the film increases, and the ability to protect the polarizer from humidity tends to be reduced.
　（機能性層の形成）
　本発明のセルロースエステルフィルム製造に際し、延伸の前および／または後で透明導電層、ハードコート層、反射防止層、易滑性層、易接着層、防眩層、バリアー層、光学補償層等の機能性層を塗設してもよい。 (Formation of functional layer)
In producing the cellulose ester film of the present invention, before and / or after stretching, a transparent conductive layer, a hard coat layer, an antireflection layer, a slippery layer, an easy adhesion layer, an antiglare layer, a barrier layer, an optical compensation layer, etc. A functional layer may be applied.
　特に、透明導電層、ハードコート層、反射防止層、易接着層、防眩層およ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、薬液処理等の各および面処理を必要に応じて施すことができる。
＜偏光板保護フィルム２＞
　その厚み方向のレターデーションＲｔのばらつきが１０ｎｍ以下である光学異方性フィルムであることを特徴とする。 In particular, it is preferable to provide at least one layer selected from a transparent conductive layer, a hard coat layer, an antireflection layer, an easy adhesion layer, an antiglare layer, and an optical compensation layer. At this time, each and surface treatment such as corona discharge treatment, plasma treatment, and chemical treatment can be performed as necessary.
<Polarizing plate protective film 2>
It is an optically anisotropic film whose variation in retardation Rt in the thickness direction is 10 nm or less.
　この光学異方性フィルムにおいて、波長５５０ｎｍにおける正面方向のレターデーションを、自動複屈折計（王子計測器社製、ＫＯＢＲＡ－２１）を用いて測定した。 In this optically anisotropic film, the retardation in the front direction at a wavelength of 550 nm was measured using an automatic birefringence meter (manufactured by Oji Scientific Instruments, KOBRA-21).
　このとき、光学異方性フィルムの幅方向に１０ｍｍ間隔で正面方向のレターデーションを測定し、その測定値の算術平均値を面内レターデーションＲｏ、厚さ方向レターデーションＲｔとし、一方で前記幅方向に１０ｍｍ間隔で測定した値の内、Ｒｔ最大値とＲｔ最小値との差を厚さ方向レターデーションＲｔのばらつきとした。 At this time, the retardation in the front direction is measured at intervals of 10 mm in the width direction of the optically anisotropic film, and the arithmetic average value of the measured values is set as the in-plane retardation Ro and the thickness direction retardation Rt. Of the values measured at intervals of 10 mm in the direction, the difference between the Rt maximum value and the Rt minimum value was defined as the variation in the thickness direction retardation Rt.
　本発明に用いられる光学異方性フィルムは、色補償、視野角補償等の光学補償の機能を備え、液晶表示装置の視認性を向上させる効果を有する。 The optically anisotropic film used in the present invention has optical compensation functions such as color compensation and viewing angle compensation, and has the effect of improving the visibility of the liquid crystal display device.
　さらに幅方向および製膜方向で複屈折性が制御されたフィルムであり、その厚み方向のレターデーションＲｔが３０～５００ｎｍであるフィルムである。 Further, it is a film whose birefringence is controlled in the width direction and the film forming direction, and a film having a retardation Rt in the thickness direction of 30 to 500 nm.
　このような光学異方性フィルムとしては、一軸性を有するフィルム、二軸性を有するフィルム、およびこれらの積層体を挙げることができ、使用する液晶セルのモードに応じて適宜選択される。 Examples of such an optically anisotropic film include a uniaxial film, a biaxial film, and a laminate thereof, which are appropriately selected according to the mode of the liquid crystal cell to be used.
　本発明の光学異方性フィルムは、下記のレターデーションを有することを特徴とする。 The optically anisotropic film of the present invention is characterized by having the following retardation.
　　　　０≦Ｒｏ≦３００
　　　３０≦Ｒｔ≦５００
　好ましくは、
　　　１．１≦Ｒｔ／Ｒｏ
　　　１０≦Ｒｏ≦２５０
　　　５０≦Ｒｔ≦４００
　さらに好ましくは、
　　　１．２≦Ｒｔ／Ｒｏ
　　　２０≦Ｒｏ≦２００
　　　８０≦Ｒｔ≦３５０
である。 0 ≦ Ro ≦ 300
30 ≦ Rt ≦ 500
Preferably,
1.1 ≦ Rt / Ro
10 ≦ Ro ≦ 250
50 ≦ Rt ≦ 400
More preferably,
1.2 ≦ Rt / Ro
20 ≦ Ro ≦ 200
80 ≦ Rt ≦ 350
It is.
　なお、面内レターデーションＲｏ、厚さ方向のレターデーションＲｔは、該フィルムの面内の主屈折率をｎｘ（ＭＤ方向）、ｎｙ（ＴＤ方向）とし、該フィルムの厚さ方向の屈折率をｎｚとし、該フィルムの厚さをｄ（ｎｍ）とした際に、Ｒｏ＝（ｎｘ－ｎｙ）×ｄ、Ｒｔ＝（（ｎｘ＋ｎｙ）／２－ｎｚ）×ｄで示される値である。 The in-plane retardation Ro and the retardation Rt in the thickness direction are defined as nx (MD direction) and ny (TD direction) as the main in-plane refractive index of the film, and the refractive index in the thickness direction of the film. When nz is assumed and the thickness of the film is d (nm), Ro = (nx−ny) × d and Rt = ((nx + ny) / 2−nz) × d.
　光学異方性フィルムとしては、熱可塑性樹脂を含有するフィルムを延伸したもの、無延伸の熱可塑性樹脂フィルム上に光学異方性層を形成したもの、熱可塑性樹脂を含有するフィルム上に光学異方性層を形成したあと、さらに延伸したもの等を用いることができる。延伸フィルムは、単層の形態であっても、複数積層した形態であってもよい。 Optically anisotropic films include those obtained by stretching a film containing a thermoplastic resin, those obtained by forming an optically anisotropic layer on an unstretched thermoplastic resin film, and optical films on a film containing a thermoplastic resin. After forming the isotropic layer, a stretched layer or the like can be used. The stretched film may be in the form of a single layer or in the form of a plurality of layers.
　これらの熱可塑性樹脂としては、透明性、低複屈折性、寸法安定性等に優れることから、特にセルロースエステル、脂環式オレフィンポリマー、ポリプロピレン系樹脂が好ましく用いられる。 As these thermoplastic resins, cellulose esters, alicyclic olefin polymers, and polypropylene resins are particularly preferably used because they are excellent in transparency, low birefringence, dimensional stability, and the like.
　熱可塑性樹脂には、必要に応じてレターデーション上昇剤を添加することができる。レターデーション上昇剤とは、熱可塑性樹脂に添加した際に、無添加の場合に比べてレターデーションを上昇させる化合物のことである。 A retardation increasing agent can be added to the thermoplastic resin as necessary. A retardation increasing agent is a compound that, when added to a thermoplastic resin, increases the retardation as compared with the case of no addition.
　セルロースエステルにレターデーション上昇剤を添加する場合には、セルロースアセテート１００質量％に対して、０．０１～２０質量％の範囲で使用することが好ましく、０．１～１０質量％の範囲で使用することがより好ましく、０．２～５質量％の範囲で使用することがさらに好ましく、０．５～２質量％の範囲で使用することが最も好ましい。 When a retardation increasing agent is added to the cellulose ester, it is preferably used in the range of 0.01 to 20% by mass and used in the range of 0.1 to 10% by mass with respect to 100% by mass of the cellulose acetate. More preferably, it is more preferably used in the range of 0.2 to 5% by mass, and most preferably in the range of 0.5 to 2% by mass.
　二種類以上のレターデーション上昇剤を併用してもよい。レターデーション上昇剤は、２５０～４００ｎｍの波長領域に最大吸収を有することが好ましい。レターデーション上昇剤は、可視領域に実質的に吸収を有していないことが好ましい。 Two or more retardation increasing agents may be used in combination. The retardation increasing agent preferably has a maximum absorption in a wavelength region of 250 to 400 nm. The retardation increasing agent preferably has substantially no absorption in the visible region.
　また、レターデーション上昇剤としては、少なくとも二つの芳香族環を有する化合物を用いることが好ましい。 Further, as the retardation increasing agent, it is preferable to use a compound having at least two aromatic rings.
　なお、本明細書において、「芳香族環」は、芳香族炭化水素環に加えて、芳香族性ヘテロ環を含む。芳香族炭化水素環は、６員環（すなわち、ベンゼン環）であることが特に好ましい。芳香族性ヘテロ環は、一般に、不飽和ヘテロ環である。 In the present specification, the “aromatic ring” includes an aromatic hetero ring in addition to an aromatic hydrocarbon ring. The aromatic hydrocarbon ring is particularly preferably a 6-membered ring (that is, a benzene ring). The aromatic heterocycle is generally an unsaturated heterocycle.
　芳香族性ヘテロ環は、５員環、６員環または７員環であることが好ましく、５員環または６員環であることがさらに好ましい。 The aromatic heterocycle is preferably a 5-membered ring, 6-membered ring or 7-membered ring, more preferably a 5-membered ring or 6-membered ring.
　芳香族性ヘテロ環は、一般に、最多の二重結合を有する。ヘテロ原子としては、窒素原子、酸素原子および硫黄原子が好ましく、窒素原子が特に好ましい。芳香族性ヘテロ環の例には、フラン環、チオフェン環、ピロール環、オキサゾール環、イソオキサゾール環、チアゾール環、イソチアゾール環、イミダゾール環、ピラゾール環、フラザン環、トリアゾール環、ピラン環、ピリジン環、ピリダジン環、ピリミジン環、ピラジン環および１、３、５－トリアジン環が含まれる。 The aromatic heterocycle generally has the most double bonds. As the hetero atom, a nitrogen atom, an oxygen atom and a sulfur atom are preferable, and a nitrogen atom is particularly preferable. Examples of aromatic heterocycles include furan ring, thiophene ring, pyrrole ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, pyrazole ring, furazane ring, triazole ring, pyran ring, pyridine ring , Pyridazine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring.
　芳香族環としては、ベンゼン環、フラン環、チオフェン環、ピロール環、オキサゾール環、チアゾール環、イミダゾール環、トリアゾール環、ピリジン環、ピリミジン環、ピラジン環および１、３、５－トリアジン環が好ましい。 The aromatic ring is preferably a benzene ring, furan ring, thiophene ring, pyrrole ring, oxazole ring, thiazole ring, imidazole ring, triazole ring, pyridine ring, pyrimidine ring, pyrazine ring and 1,3,5-triazine ring.
　レターデーション上昇剤が有する芳香族環の数は、２～２０であることが好ましく、２～１２であることがより好ましく、２～８であることがさらに好ましく、２～６であることが最も好ましい。 The number of aromatic rings contained in the retardation increasing agent is preferably 2 to 20, more preferably 2 to 12, still more preferably 2 to 8, and most preferably 2 to 6. preferable.
　二つの芳香族環の結合関係は、（ａ）縮合環を形成する場合、（ｂ）単結合で直結する場合および（ｃ）連結基を介して結合する場合に分類できる（芳香族環のため、スピロ結合は形成できない）。結合関係は、（ａ）～（ｃ）のいずれでもよい。 The bonding relationship between two aromatic rings can be classified into (a) when a condensed ring is formed, (b) when directly linked by a single bond, and (c) when linked via a linking group (for aromatic rings). , Spiro bonds cannot be formed). The bond relationship may be any of (a) to (c).
　前記熱可塑性樹脂を含むフィルムを延伸する方法としては、テンターを用いて横方向に一軸延伸する方法等の一軸延伸法；固定するクリップの間隔が開かれて縦方向の延伸と同時にガイドレールの広がり角度により横方向に延伸する同時二軸延伸法や、ロール間の周速の差を利用して縦方向に延伸したあとにその両端部をクリップ把持してテンターを用いて横方向に延伸する逐次二軸延伸法などの二軸延伸法；横または縦方向に左右異なる速度の送り力もしくは引張り力または引取り力を付加できるようにしたテンター延伸機や、横または縦方向に左右等速度の送り力もしくは引張り力または引取り力を付加できるようにして、移動する距離が同じで延伸角度θを固定できるようにしたもしくは移動する距離が異なるようにしたテンター延伸機を用いて斜め延伸する方法：が挙げられる。 As a method of stretching the film containing the thermoplastic resin, a uniaxial stretching method such as a method of stretching uniaxially in a transverse direction using a tenter; a gap between fixed clips is opened and a guide rail spreads simultaneously with stretching in the longitudinal direction. Sequential biaxial stretching method that stretches in the transverse direction according to the angle, or stretches in the longitudinal direction using the difference in peripheral speed between rolls, then grips both ends of the clip and stretches in the transverse direction using a tenter Biaxial stretching method such as biaxial stretching method; Tenter stretching machine that can add feed force or pulling force or pulling force with different left and right speeds in the horizontal or vertical direction, and horizontal and vertical feed speeds in the horizontal and vertical directions Tenter extension that can apply force, pulling force or pulling force so that the moving distance is the same and the stretching angle θ can be fixed or the moving distance is different. How to obliquely stretched with the machine: and the like.
　延伸温度としては、光学異方性フィルムを形成する材料、特に樹脂の中で、ガラス転移温度が最も低い樹脂のガラス転移温度をＴｇとすると、通常Ｔｇ～Ｔｇ＋５０℃の範囲で行うことができる。 The stretching temperature can be usually in the range of Tg to Tg + 50 ° C., where Tg is the glass transition temperature of the resin having the lowest glass transition temperature among the materials forming the optically anisotropic film, particularly the resin.
　また、前記光学異方性フィルムの形成には、支持体上に高分子化合物や液晶性化合物を用いて異方性層を形成し光学異方性フィルムとすることができる。これらは、単独で使用してもよいし併用してもよい。 In addition, the optically anisotropic film can be formed by forming an anisotropic layer using a polymer compound or a liquid crystal compound on a support. These may be used alone or in combination.
　前記高分子化合物としては、ポリアミド、ポリイミド、ポリエステル、ポリエーテルケトン等を使用できる。 As the polymer compound, polyamide, polyimide, polyester, polyether ketone, or the like can be used.
　具体的には、特表平８－５１１８１２号（国際公開番号　ＷＯ９４／２４１９１号）、同２０００－５１１２９６号（国際公開番号　ＷＯ９７／４４７０４号）等記載の化合物が挙げることができる。 Specifically, compounds described in JP-T-8-511812 (International Publication No. WO94 / 24191), 2000-511296 (International Publication No. WO97 / 44704) and the like can be mentioned.
　前記液晶性化合物としては、棒状液晶でも、ディスコティック液晶でも良く、またそれらが高分子液晶、もしくは低分子液晶、さらには、低分子液晶が架橋され液晶性を示さなくなったものも含まれる。 The liquid crystalline compound may be a rod-like liquid crystal or a discotic liquid crystal, and these include a polymer liquid crystal or a low molecular liquid crystal, and those in which a low molecular liquid crystal is cross-linked and no longer exhibits liquid crystallinity.
　棒状液晶の好ましい例としては、特開２０００－３０４９３２号公報に記載のものが挙げられる。 Preferred examples of the rod-like liquid crystal include those described in JP-A No. 2000-304932.
　ディスコティック液晶の好ましい例としては、特開平８－５０２０６号公報に記載のものが挙げることができる。 Preferred examples of the discotic liquid crystal include those described in JP-A-8-50206.
　また、前記光学異方性層の厚さは、０．１～１０μｍであることが好ましく、０．５～５μｍであることがさらに好ましく、０．７～５μｍであることが最も好ましい。 The thickness of the optically anisotropic layer is preferably from 0.1 to 10 μm, more preferably from 0.5 to 5 μm, and most preferably from 0.7 to 5 μm.
　ただし、液晶セルのモードによっては、高い光学的異方性を得るために、３～１０μｍとする場合もある。 However, depending on the mode of the liquid crystal cell, it may be 3 to 10 μm in order to obtain high optical anisotropy.
　光学異方性層を含む光学異方性フィルムの製造方法は、特に限定されず、例えば、前記高分子化合物および／または液晶性化合物を熱可塑性樹脂を含むフィルム等に塗工して塗工膜を製造し、その塗工膜をさらに延伸や収縮させることにより製造できる。
＜偏光板＞
　本発明の偏光板について述べる。 The method for producing the optically anisotropic film including the optically anisotropic layer is not particularly limited. For example, the polymer film and / or the liquid crystal compound is applied to a film containing a thermoplastic resin or the like to form a coating film. Can be produced by further stretching or shrinking the coating film.
<Polarizing plate>
The polarizing plate of the present invention will be described.
　偏光板は一般的な方法で作製することができる。本発明のセルロースエステルフィルムをアルカリ鹸化処理し、処理したフィルムを、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、完全鹸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 polarizing plate can be produced by a general method. The cellulose ester film of the present invention is preferably subjected to alkali saponification treatment, and the treated film is bonded to at least one surface of a polarizer prepared by immersing and stretching in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. .
　セルロースエステルフィルム以外の光学異方性フィルムの場合は、アクリル系またはウレタン系接着剤を使用することが好ましい。 In the case of an optically anisotropic film other than the cellulose ester film, it is preferable to use an acrylic or urethane adhesive.
　本発明の偏光子としては、ポリビニルアルコール系偏光フィルムであって、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。 The polarizer of the present invention is a polyvinyl alcohol polarizing film, which includes a polyvinyl alcohol film dyed with iodine and a dichroic dye 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。 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.
　該偏光子の面上に、本発明のセルロースエステルフィルムの片面を貼り合わせて偏光板を形成する。好ましくは完全鹸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 laminating one side of the cellulose ester film of the present invention on the surface of the polarizer. It is preferably bonded with an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like.
　本発明に従い溶融流延製膜方法により製造される長尺状セルロースエステルフィルムは、長尺状の偏光子（偏光フィルム）とアルカリケン化処理を施して貼合することができるため、特に１００ｍ以上の長尺で生産的効果が得られ、１５００ｍ、２５００ｍ、５０００ｍとより長尺化する程偏光板製造の生産的効果が高まる。 The long cellulose ester film produced by the melt casting film-forming method according to the present invention can be bonded with a long polarizer (polarizing film) by subjecting it to alkali saponification treatment. The productive effect is obtained with a long length of 1, and the longer the length is 1500 m, 2500 m, and 5000 m, the higher the productive effect of manufacturing the polarizing plate.
　また、本発明のセルロースエステルフィルムを用いた偏光板はリワーク性に優れるため、偏光板収率が向上するという効果も得ることができる。
＜液晶表示装置＞
　本発明のセルロースエステルフィルムを含む偏光板は、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る。 Moreover, since the polarizing plate using the cellulose ester film of this invention is excellent in rework property, the effect that a polarizing plate yield improves can also be acquired.
<Liquid crystal display device>
The polarizing plate containing the cellulose ester film of the present invention can exhibit high display quality as compared with a normal polarizing plate.
　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－Ｐｌａｎｅ　Ｓｗｉｔｃｈｉｎｇ）モード等に用いることができる。 The polarizing plate of the present invention includes an MVA (Multi-domain Vertical Alignment) mode, a PVA (Patterned Vertical Alignment) mode, a CPA (Continuous Pinweal Alignment) mode, an OCB (Optical AlignSensing mode) Can be used.
　液晶表示装置はカラー化および動画表示用の装置として応用され、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。 The liquid crystal display device is applied as a device for colorization and moving image display, and the display quality is improved by the present invention, and the contrast is improved and the resistance of the polarizing plate is improved. .
　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。
実施例１
＜セルロースエステルの合成＞
　特表平６－５０１０４０号公報の例Ｂを参考にして、プロピオン酸、酪酸、酢酸の添加量を調整して、アセチル基置換度、プロピオニル基置換度、ブチリル基置換度を表１のように変化させた６種類のセルロースエステルを合成した。 EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.
Example 1
<Synthesis of cellulose ester>
With reference to Example B of JP-T-6-501040, the amount of propionic acid, butyric acid, and acetic acid was adjusted, and the degree of acetyl group substitution, propionyl group substitution, and butyryl group substitution were as shown in Table 1. Six kinds of changed cellulose esters were synthesized.
Figure JPOXMLDOC01-appb-T000023
Figure JPOXMLDOC01-appb-T000023
　得られたセルロースエステルの置換度は、ＡＳＴＭ－Ｄ８１７－９６に基づいて算出した。
＜溶融法による偏光板保護フィルム１の作製＞
　８０℃で６時間乾燥済み（水分率２００ｐｐｍ）のセルロースエステルＣ－１、１００質量部、一般式（３）の可塑剤Ｎｏ．６４を４質量部、スクロースオクタベンゾエート（分子量８６３）４質量部、紫外線吸収剤ＬＡ－３１（ＡＤＥＫＡ（株）製）１．０５質量部、Ｉｒｇａｎｏｘ１０１０（チバ・ジャパン（株）製）０．５質量部、アデカスタブＰ
ＥＰ－３６（ＡＤＥＫＡ（株）製）０．０８質量部、ＳｕｍｉｌｉｚｅｒＧＳ（住友化学（株）製）０．２質量部、シーホスターＫＥＰ－３０（日本触媒（株）製）０．１質量部を真空ナウターミキサーで８０℃、１Ｔｏｒｒで３時間混合しながらさらに乾燥した。 The degree of substitution of the obtained cellulose ester was calculated based on ASTM-D817-96.
<Preparation of Polarizing Plate Protective Film 1 by Melting Method>
Cellulose ester C-1, which has been dried at 80 ° C. for 6 hours (water content: 200 ppm), 100 parts by mass, plasticizer No. 1 of general formula (3) 4 parts by mass of 64, 4 parts by mass of sucrose octabenzoate (molecular weight 863), 1.05 parts by mass of UV absorber LA-31 (manufactured by ADEKA), 0.5 mass of Irganox 1010 (manufactured by Ciba Japan) Department, Adeka Stub P
Vacuum 0.08 parts by mass of EP-36 (manufactured by ADEKA Co., Ltd.), 0.2 parts by mass of Sumilizer GS (manufactured by Sumitomo Chemical Co., Ltd.), and 0.1 parts by mass of Seahoster KEP-30 (manufactured by Nippon Shokubai Co., Ltd.) Further drying was performed while mixing with a Nauta mixer at 80 ° C. and 1 Torr for 3 hours.
　得られた混合物を、二軸式押出機を用いて２３５℃で溶融混合しペレット化した。 The obtained mixture was melt-mixed at 235 ° C. using a twin-screw extruder and pelletized.
　セルロースエステルフィルムの製膜は図１に示す製造装置で行った。 The cellulose ester film was produced using the production apparatus shown in FIG.
　ペレット（水分率５０ｐｐｍ）を、１軸押出機を用いてＴダイから表面温度が１００℃の第１冷却ロール上に溶融温度２４５℃でフィルム状に溶融押し出し、初期膜厚１２８μｍ、幅１．０ｍのキャストフィルムを毎分３５ｍの長さで得た。 Pellets (water content 50 ppm) were melt extruded from a T die onto a first cooling roll having a surface temperature of 100 ° C. at a melting temperature of 245 ° C. using a single-screw extruder, with an initial film thickness of 128 μm and a width of 1.0 m. A cast film of 35 m / min was obtained.
　この際第１冷却ロール上でフィルムを２ｍｍ厚の金属表面を有する弾性タッチロールで押圧した。 At this time, the film was pressed on the first cooling roll with an elastic touch roll having a 2 mm thick metal surface.
　得られたフィルムを、まずロール周速差を利用した延伸機によって１９５℃で製膜方向に６０％で延伸速度１０００％／ｍｉｎで延伸し、膜厚８０μｍの保護フィルム１０１を得た。 The obtained film was first stretched at 195 ° C. in the film-forming direction at a stretching rate of 1000% / min at a stretching speed of 1000% / min at 195 ° C. using a stretching machine utilizing a roll peripheral speed difference to obtain a protective film 101 having a thickness of 80 μm.
　次に、セルロースエステル、延伸速度、延伸倍率、初期膜厚を表２のように変更した以外は本発明のセルロースエステルフィルム１０１と同様にして、膜厚８０μｍの本発明および比較の保護フィルム１０２～１２２を得た。 Next, in the same manner as the cellulose ester film 101 of the present invention except that the cellulose ester, stretching speed, stretching ratio, and initial film thickness were changed as shown in Table 2, the present invention having a film thickness of 80 μm and the comparative protective films 102 to 122 was obtained.
　このとき幅手方向の延伸は、製膜方向に延伸したあと、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て延伸ゾーンにおいて１６５℃で行い、その後３０℃まで冷却し、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を得た。 At this time, in the width direction, after stretching in the film forming direction, a preheating zone, a stretching zone, a holding zone, and a cooling zone (a neutral zone for ensuring thermal insulation between the zones is also provided between the zones). The film was obtained in a stretching zone at 165 ° C. in a stretching zone, then cooled to 30 ° C., released from the clip, and the clip gripping part was cut off.
　〈溶液流延製膜法によるフィルム試料１２３、１２４の作製〉
　シーホスターＫＥＰ－３０（日本触媒（株）製）１１質量部、エタノール８９質量部以上をディゾルバーで５０分間攪拌混合したあと、マントンゴーリンで分散をし、微粒子分散液を作製した。 <Production of film samples 123 and 124 by a solution casting film forming method>
11 parts by weight of Seahoster KEP-30 (manufactured by Nippon Shokubai Co., Ltd.) and 89 parts by weight or more of ethanol were stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin to prepare a fine particle dispersion.
　メチレンクロライド９９質量部を入れた溶解タンクにセルロースエステルＣ－１、４質量部を添加し、加熱して完全に溶解させたあと、これを安積濾紙（株）製の安積濾紙Ｎｏ．２４４を使用して濾過した。 After adding 4 parts by mass of cellulose ester C-1 to a dissolution tank containing 99 parts by mass of methylene chloride and heating to completely dissolve it, this was added to Azumi filter paper No. 1 manufactured by Azumi Filter Paper Co., Ltd. Filtered using 244.
　濾過後のセルロースエステル溶液を十分に攪拌しながら、ここに微粒子分散液を１１質量部ゆっくりと添加した。 11 parts by mass of the fine particle dispersion was slowly added thereto while sufficiently stirring the filtered cellulose ester solution.
　さらに、アトライターにて分散を行ったあと、日本精線（株）製のファインメットＮＦで濾過し、微粒子添加液を調製した。 Further, after dispersion with an attritor, the mixture was filtered with Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution.
　下記組成の主ドープ液を調製した。まず加圧溶解タンクにメチレンクロライドとエタノールを添加した。メチレンクロライドの一部（約４０質量部）はあらかじめ分けておき、溶剤の入った加圧溶解タンクにセルロースエステルを攪拌しながら投入した。 A main dope solution having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. A part of methylene chloride (about 40 parts by mass) was divided in advance, and the cellulose ester was added to a pressurized dissolution tank containing a solvent while stirring.
　これを加熱し、攪拌しながら、完全に溶解し、さらに可塑剤を添加、溶解させた。これを安積濾紙（株）製の安積濾紙Ｎｏ．２４４を使用して濾過し、主ドープ液を調製した。 This was heated, stirred and completely dissolved, and a plasticizer was added and dissolved. This was designated as Azumi Filter Paper No. The main dope solution was prepared by filtration using 244.
　主ドープ液１００質量部と微粒子添加液２質量部となるように加えて、インラインミキサー（東レ静止型管内混合機　Ｈｉ－Ｍｉｘｅｒ、ＳＷＪ）で十分に混合し、ベルト流延装置により、幅２ｍのステンレスバンド支持体に均一に流延し剥離、乾燥させた。 In addition to 100 parts by mass of the main dope solution and 2 parts by mass of the fine particle additive solution, the dope is sufficiently mixed by an in-line mixer (Toray static type in-pipe mixer Hi-Mixer, SWJ), and is 2 m in width by a belt casting apparatus. It was cast uniformly on a stainless steel band support, peeled off and dried.
　その後試料１０１同様に、ロール周速差を利用した延伸機によって１９５℃、１５０００％／ｍｉｎで６０％延伸し、さらにテンターにて幅手方向に１７０℃、７００％／ｍｉｎで７０％延伸し、比較試料１２３を得た。 Thereafter, as with sample 101, the film was stretched 60% at 195 ° C. and 15000% / min by a stretching machine utilizing the difference in peripheral speed of the roll, and further stretched 70% at 170 ° C. and 700% / min in the width direction by a tenter. A comparative sample 123 was obtained.
　〈主ドープ液の組成〉
　メチレンクロライド　　　　　　　　　　　　　　　　　　　　　　　３００質量部
　エタノール　　　　　　　　　　　　　　　　　　　　　　　　　　　　５２質量部
　セルロースエステル（Ｃ－１）　　　　　　　　　　　　　　　　　　１００質量部
　一般式（３）で表される可塑剤Ｎｏ．６４　　　　　　　　　　　　　　　８質量部
　Ｔｉｎｕｖｉｎ９００（チバ・ジャパン株式会社製）　　　　　　　　１．２質量部
　次に、延伸速度、延伸倍率、初期膜厚を表１のように変更した以外はセルロースエステルフィルム１２３と同様にして、膜厚８０μｍの保護フィルム１２４を得ようとしたが、製膜方向への延伸した際に破断してしまった。 <Composition of main dope solution>
Methylene chloride 300 parts by mass Ethanol 52 parts by mass Cellulose ester (C-1) 100 parts by mass Plasticizer No. 2 represented by the general formula (3) 64 8 parts by mass Tinuvin 900 (manufactured by Ciba Japan Co., Ltd.) 1.2 parts by mass Next, except for changing the stretching speed, the stretching ratio, and the initial film thickness as shown in Table 1, the film is the same as the cellulose ester film 123. An attempt was made to obtain a protective film 124 having a thickness of 80 μm, but it broke when stretched in the film forming direction.
　さらに比較試料として特開２００７－２２１６号公報の実施例１に記載の比較試料１および比較試料２を作製し、それぞれ試料１２５、１２６とした。 Furthermore, Comparative Sample 1 and Comparative Sample 2 described in Example 1 of Japanese Patent Application Laid-Open No. 2007-2216 were produced as comparative samples, and they were designated Samples 125 and 126, respectively.
　これらの保護フィルム１０１～１２６について含有溶媒量を測定したところ試料１０１～１２２、１２５、１２６は０．０１質量部以下であり、試料１２３、１２４は０．１％であった。 When the amount of the solvent contained in these protective films 101 to 126 was measured, the samples 101 to 122, 125, and 126 were 0.01 parts by mass or less, and the samples 123 and 124 were 0.1%.
　また音速について評価した。結果は表２に示す。 The sound speed was also evaluated. The results are shown in Table 2.
Figure JPOXMLDOC01-appb-T000024
Figure JPOXMLDOC01-appb-T000024
　〈含有溶媒量〉
　各試料を２０ｍｌの密閉ガラス容器に入れ、下記ヘッドスペース加熱条件にて処理したあと、下記ガスクロマトグラフィーにて予め使用した溶媒について検量線を作成し測定を行った。含有溶媒量は、偏光板保護フィルム１の全体の質量に対する質量部で表した。 <Contained solvent amount>
Each sample was placed in a 20 ml sealed glass container, treated under the following headspace heating conditions, and then a calibration curve was prepared and measured for the solvent used in advance by the following gas chromatography. The amount of solvent contained was expressed in parts by mass relative to the total mass of the polarizing plate protective film 1.
　機器：ＨＰ社　５８９０ＳＥＲＩＥＳ II
　カラム：Ｊ＆Ｗ社　ＤＢ－ＷＡＸ（内径０．３２ｍｍ、長さ３０ｍ）
　検出：ＦＩＤ
　ＧＣ昇温条件：４０℃で５分間保持したあと、８０℃／分で１００℃まで昇温
　ヘッドスペース加熱条件：１２０℃で２０ｍｉｎ
　〈音速〉
　本発明のセルロースフィルムの音速は、２３℃９０％ＲＨ環境に試験試料を１時間設置し、その後同環境を１００℃へ昇温させ３時間保持した後２３℃５５％ＲＨに１時間放置し、同環境下ＳＯＮＩＣ　ＳＨＥＥＴ　ＴＥＳＴＥＲ（ＳＳＴ－１１０型、野村商事（株）製）を用いてフィルム製膜方向および幅手方向について測定した。
＜ハードコート層・反射防止層フィルムの作製＞
　作製した偏光板保護フィルム１の試料Ｎｏ１～１２６を用いて、その一方の面にハードコート層および反射防止層を形成し、ハードコート付き反射防止フィルム１０１～１２６を作製した。 Equipment: HP 5890SERIES II
Column: J-W DB-WAX (inner diameter 0.32 mm, length 30 m)
Detection: FID
GC temperature rising condition: held at 40 ° C. for 5 minutes, then heated to 100 ° C. at 80 ° C./min. Headspace heating condition: 20 minutes at 120 ° C.
<Sound speed>
The speed of sound of the cellulose film of the present invention is as follows: a test sample is placed in a 23 ° C. and 90% RH environment for 1 hour, then the temperature is raised to 100 ° C. and held for 3 hours, and then left at 23 ° C. and 55% RH for 1 hour; Under the same environment, the film forming direction and the width direction were measured using a SONIC SHEET TESTER (SST-110 type, manufactured by Nomura Corporation).
<Preparation of hard coat layer / antireflection layer film>
Using the produced polarizing plate protective film 1 samples No. 1 to 126, a hard coat layer and an antireflection layer were formed on one surface thereof, and antireflection films 101 to 126 with hard coat were produced.
　〈ハードコート層〉
　下記ハードコート層組成物を乾燥膜厚３．５μｍとなるように塗布し、８０℃にて１分間乾燥した。次に高圧水銀ランプ（８０Ｗ）にて１５０ｍＪ／ｃｍ2の条件で硬化させ、ハードコート層を有するハードコートフィルムを作製した。ハードコート層の屈折率は１．５０であった。 <Hard coat layer>
The following hard coat layer composition was applied to a dry film thickness of 3.5 μm and dried at 80 ° C. for 1 minute. Next, it was cured under a condition of 150 mJ / cm 2 with a high-pressure mercury lamp (80 W) to produce a hard coat film having a hard coat layer. The refractive index of the hard coat layer was 1.50.
　〈ハードコート層組成物（Ｃ－１）〉
　ジペンタエリスリトールヘキサアクリレート（２量体以上の成分を２割程度含む）
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　１０８質量部
　イルガキュア１８４（チバ・ジャパン（株）製）　　　　　　　　　　　　２質量部
　プロピレングリコールモノメチルエーテル　　　　　　　　　　　　　１８０質量部
　酢酸エチル　　　　　　　　　　　　　　　　　　　　　　　　　　　１２０質量部
　〈中屈折率層〉
　前記ハードコートフィルムのハードコート層の上に、下記中屈折率層組成物を押し出しコーターで塗布し、８０℃、０．１ｍ／秒の条件で１分間乾燥させた。 <Hardcoat layer composition (C-1)>
Dipentaerythritol hexaacrylate (contains about 20% of dimer or higher components)
108 parts by mass Irgacure 184 (manufactured by Ciba Japan Co., Ltd.) 2 parts by mass Propylene glycol monomethyl ether 180 parts by mass Ethyl acetate 120 parts by mass <Medium refractive index layer>
On the hard coat layer of the hard coat film, the following medium refractive index layer composition was applied by an extrusion coater and dried for 1 minute at 80 ° C. and 0.1 m / second.
　この時、指触乾燥終了（塗布面を指で触って乾燥していると感じる状態）までは非接触フローターを使用した。非接触フローターとしては、ベルマッティク社製の水平フロータータイプのエアータンバーを使用した。 At this time, a non-contact floater was used until completion of finger touch drying (a state in which the coated surface was touched and felt dry). As the non-contact floater, a horizontal floater type air tumbler manufactured by Belmatik was used.
　フローター内静圧は９．８ｋＰａとし、約２ｍｍ幅手方向に均一に浮上させて搬送した。乾燥後、高圧水銀ランプ（８０Ｗ）を用いて紫外線を、１３０ｍＪ／ｃｍ2照射して硬化させ、中屈折率層を有する中屈折率層フィルムを作製した。 The static pressure in the floater was set to 9.8 kPa, and the floater was lifted uniformly in the width direction of about 2 mm and conveyed. After drying, a medium refractive index layer film having a medium refractive index layer was produced by curing by irradiating ultraviolet rays with 130 mJ / cm 2 using a high pressure mercury lamp (80 W).
　この中屈折率層フィルムの中屈折率層の厚さは８４ｎｍで、屈折率は１．６６であった。 The thickness of the middle refractive index layer of this middle refractive index layer film was 84 nm, and the refractive index was 1.66.
　〈中屈折率層組成物〉
　２０％ＩＴＯ微粒子分散物（平均粒径７０ｎｍ、イソプロピルアルコール溶液）
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　１００質量部
　ジペンタエリスリトールヘキサアクリレート　　　　　　　　　　　　６．４質量部
　イルガキュア１８４（チバ・ジャパン（株）製）　　　　　　　　　　１．６質量部
　テトラブトキシチタン　　　　　　　　　　　　　　　　　　　　　　４．０質量部
　１０％ＦＺ－２２０７（日本ユニカー社製、プロピレングリコールモノメチルエーテル溶液）　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　３．０質量部
　イソプロピルアルコール　　　　　　　　　　　　　　　　　　　　　５３０質量部
　メチルエチルケトン　　　　　　　　　　　　　　　　　　　　　　　　９０質量部
　プロピレングリコールモノメチルエーテル　　　　　　　　　　　　　２６５質量部
　〈高屈折率層〉
　前記中屈折率層の上に、下記高屈折率層組成物を押し出しコーターで塗布し、８０℃、０．１ｍ／秒の条件で１分間乾燥させた。この時、指触乾燥終了（塗布面を指で触って乾燥していると感じる状態）までは非接触フローターを使用した。 <Medium refractive index layer composition>
20% ITO fine particle dispersion (average particle size 70 nm, isopropyl alcohol solution)
100 parts by mass Dipentaerythritol hexaacrylate 6.4 parts by mass Irgacure 184 (manufactured by Ciba Japan Co., Ltd.) 1.6 parts by mass Tetrabutoxy titanium 4.0 parts by mass 10% FZ-2207 (manufactured by Nippon Unicar Co., Ltd., propylene glycol) Monomethyl ether solution) 3.0 parts by mass Isopropyl alcohol 530 parts by mass Methyl ethyl ketone 90 parts by mass Propylene glycol monomethyl ether 265 parts by mass <High refractive index layer>
On the medium refractive index layer, the following high refractive index layer composition was applied by an extrusion coater and dried at 80 ° C. and 0.1 m / second for 1 minute. At this time, a non-contact floater was used until completion of touch drying (a state where the coated surface was touched with a finger and felt dry).
　非接触フローターは中屈折率層形成と同じ条件とした。乾燥後、高圧水銀ランプ（８０Ｗ）を用いて紫外線を１３０ｍＪ／ｃｍ2照射して硬化させ、高屈折率層を有する高屈折率層フィルムを作製した。 The non-contact floater was under the same conditions as the formation of the middle refractive index layer. After drying, ultraviolet rays were irradiated by 130 mJ / cm 2 using a high pressure mercury lamp (80 W) and cured to produce a high refractive index layer film having a high refractive index layer.
　〈高屈折率層組成物〉
　テトラ（ｎ）ブトキシチタン　　　　　　　　　　　　　　　　　　　　９５質量部
　ジメチルポリシロキサン（信越化学社製　ＫＦ－９６－１０００ＣＳ）　　１質量部
　γ－メタクリロキシプロピルトリメトキシシシラン（信越化学社製　ＫＢＭ５０３）
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　５質量部
　プロピレングリコールモノメチルエーテル　　　　　　　　　　　　１７５０質量部
　イソプロピルアルコール　　　　　　　　　　　　　　　　　　　　３４５０質量部
　メチルエチルケトン　　　　　　　　　　　　　　　　　　　　　　　６００質量部
　なお、この高屈折率層フィルムの高屈折率層の厚さ５０μｍ、屈折率は１．８２であった。 <High refractive index layer composition>
95 parts by mass of tetra (n) butoxytitanium dimethylpolysiloxane (KF-96-1000CS manufactured by Shin-Etsu Chemical Co., Ltd.) 1 part by mass of γ-methacryloxypropyltrimethoxysilane (KBM503 manufactured by Shin-Etsu Chemical Co., Ltd.)
5 parts by mass Propylene glycol monomethyl ether 1750 parts by mass Isopropyl alcohol 3450 parts by mass Methyl ethyl ketone 600 parts by mass The thickness of the high refractive index layer of this high refractive index layer film was 50 μm and the refractive index was 1.82.
　〈低屈折率層〉
　最初にシリカ系微粒子（空洞粒子）の調製を行った。
（シリカ系微粒子Ｐ－１の調製）
　平均粒径５ｎｍ、ＳｉＯ2濃度２０質量部のシリカゾル１００ｇと純水１９００ｇの混合物を８０℃に加温した。この反応母液のｐＨは１０．５であり、同母液にＳｉＯ2として０．９８質量部のケイ酸ナトリウム水溶液９０００ｇとＡｌ2Ｏ3として１．０２質量部のアルミン酸ナトリウム水溶液９０００ｇとを同時に添加した。 <Low refractive index layer>
First, silica-based fine particles (cavity particles) were prepared.
(Preparation of silica-based fine particles P-1)
A mixture of 100 g of silica sol having an average particle diameter of 5 nm and a SiO 2 concentration of 20 parts by mass and 1900 g of pure water was heated to 80 ° C. The pH of this reaction mother liquor was 10.5, and 9000 g of 0.98 parts by mass of sodium silicate aqueous solution as SiO 2 and 9000 g of 1.02 parts by mass of sodium aluminate aqueous solution as Al 2 O 3 were simultaneously added to the mother liquor. did.
　その間、反応液の温度を８０℃に保持した。反応液のｐＨは添加直後、１２．５に上昇し、その後、ほとんど変化しなかった。 Meanwhile, the temperature of the reaction solution was kept at 80 ° C. The pH of the reaction solution rose to 12.5 immediately after the addition and hardly changed thereafter.
　添加終了後、反応液を室温まで冷却し、限外濾過膜で洗浄して固形分濃度２０質量部のＳｉＯ2・Ａｌ2Ｏ3核粒子分散液を調製した。（工程（ａ））
　この核粒子分散液５００ｇに純水１７００ｇを加えて９８℃に加温し、この温度を保持しながら、ケイ酸ナトリウム水溶液を陽イオン交換樹脂で脱アルカリして得られたケイ酸液（ＳｉＯ2濃度３．５質量部）３０００ｇを添加して第１シリカ被覆層を形成した核粒子の分散液を得た。（工程（ｂ））
　次いで、限外濾過膜で洗浄して固形分濃度１３質量部になった第１シリカ被覆層を形成した核粒子分散液５００ｇに純水１１２５ｇを加え、さらに濃塩酸（３５．５％）を滴下してｐＨ１．０とし、脱アルミニウム処理を行った。 After completion of the addition, the reaction solution was cooled to room temperature and washed with an ultrafiltration membrane to prepare a SiO 2 .Al 2 O 3 core particle dispersion having a solid content concentration of 20 parts by mass. (Process (a))
1700 g of pure water is added to 500 g of this core particle dispersion and heated to 98 ° C., and while maintaining this temperature, a silicate solution (SiO 2) obtained by dealkalizing a sodium silicate aqueous solution with a cation exchange resin. A dispersion of core particles in which a first silica coating layer was formed by adding 3000 g (concentration: 3.5 parts by mass) was obtained. (Process (b))
Next, 1125 g of pure water is added to 500 g of the core particle dispersion liquid that has been washed with an ultrafiltration membrane to form a first silica coating layer having a solid content concentration of 13 parts by mass, and concentrated hydrochloric acid (35.5%) is further added dropwise. The pH was adjusted to 1.0 and dealumination was performed.
　次いで、ｐＨ３の塩酸水溶液１０Ｌと純水５Ｌを加えながら限外濾過膜で溶解したアルミニウム塩を分離し、第１シリカ被覆層を形成した核粒子の構成成分の一部を除去したＳｉＯ2・Ａｌ2Ｏ3多孔質粒子の分散液を調製した（工程（ｃ））。 Next, the aluminum salt dissolved in the ultrafiltration membrane was separated while adding 10 L of hydrochloric acid aqueous solution of pH 3 and 5 L of pure water, and SiO 2 · Al from which some of the constituent components of the core particles forming the first silica coating layer were removed. A dispersion of 2 O 3 porous particles was prepared (step (c)).
　上記多孔質粒子分散液１５００ｇと、純水５００ｇ、エタノール１，７５０ｇ及び２８％アンモニア水６２６ｇとの混合液を３５℃に加温したあと、エチルシリケート（ＳｉＯ2２８質量部）１０４ｇを添加し、第１シリカ被覆層を形成した多孔質粒子の表面をエチルシリケートの加水分解重縮合物で被覆して第２シリカ被覆層を形成した。 A mixture of 1500 g of the above porous particle dispersion, 500 g of pure water, 1,750 g of ethanol and 626 g of 28% ammonia water is heated to 35 ° C., and then 104 g of ethyl silicate (28 parts by mass of SiO 2 ) is added. The surface of the porous particles on which the first silica coating layer was formed was coated with a hydrolyzed polycondensate of ethyl silicate to form a second silica coating layer.
　次いで、限外濾過膜を用いて溶媒をエタノールに置換した固形分濃度２０質量部のシリカ系微粒子の分散液を調製した。 Subsequently, a dispersion of silica-based fine particles having a solid content concentration of 20 parts by mass was prepared by replacing the solvent with ethanol using an ultrafiltration membrane.
　このシリカ系微粒子の第１シリカ被覆層の厚さ、平均粒径、ＭＯｘ／ＳｉＯ2（モル比）、及び屈折率を表３に示す。 Table 3 shows the thickness, average particle diameter, MOx / SiO 2 (molar ratio), and refractive index of the first silica coating layer of the silica-based fine particles.
　ここで、平均粒径は動的光散乱法により測定し、屈折率は標準屈折液としてＣＡＲＧＩＬＬ製のＳｅｒｉｅｓＡ、ＡＡを用い、以下の方法で測定した。 Here, the average particle diameter was measured by a dynamic light scattering method, and the refractive index was measured by the following method using Series A and AA made by CARGILL as a standard refractive liquid.
　〈粒子の屈折率の測定方法〉
（１）粒子分散液をエバポレーターに採り、分散媒を蒸発させる。
（２）これを１２０℃で乾燥し、粉末とする。
（３）屈折率が既知の標準屈折液を２、３滴ガラス板上に滴下し、これに上記粉末を混合する。
（４）上記（３）の操作を種々の標準屈折液で行い、混合液が透明になったときの標準屈折液の屈折率をコロイド粒子の屈折率とする。 <Measuring method of particle refractive index>
(1) The particle dispersion is taken in an evaporator and the dispersion medium is evaporated.
(2) This is dried at 120 ° C. to obtain a powder.
(3) A standard refraction liquid having a known refractive index is dropped on a glass plate of a few drops, and the above powder is mixed therewith.
(4) The operation of (3) above is performed with various standard refractive liquids, and the refractive index of the standard refractive liquid when the mixed liquid becomes transparent is used as the refractive index of the colloidal particles.
Figure JPOXMLDOC01-appb-T000025
Figure JPOXMLDOC01-appb-T000025
　（低屈折率層の形成）
　Ｓｉ（ＯＣ2Ｈ5）4を９５ｍｏｌ％、Ｃ3Ｆ7－（ＯＣ3Ｆ6）24－Ｏ－（ＣＦ2）2－Ｃ2Ｈ4－Ｏ－ＣＨ2Ｓｉ（ＯＣＨ3）3を５ｍｏｌ％で混合したマトリックスに対して、平均粒径６０ｎｍの上記シリカ系微粒子Ｐ－１を３５質量部添加し、１．０Ｎ－ＨＣｌを触媒に用いて、さらに溶媒で希釈した低屈折率コーティング剤を作製した。 (Formation of a low refractive index layer)
95 mol% of Si (OC 2 H 5 ) 4 and 5 mol of C 3 F 7 — (OC 3 F 6 ) 24 —O— (CF 2 ) 2 —C 2 H 4 —O—CH 2 Si (OCH 3 ) 3 The low-refractive-index coating agent diluted with a solvent by adding 35 parts by mass of the above silica-based fine particles P-1 having an average particle diameter of 60 nm to a matrix mixed at a ratio of 1.0 N-HCl as a catalyst. Produced.
　上記活性線硬化樹脂層または高屈折率層上にダイコーター法を用いてコーティング溶液を膜厚１００ｎｍで塗布し、１２０℃で１分間乾燥したあと、紫外線照射を行うことにより、屈折率１．３７の低屈折率層を形成した。
＜偏光板保護フィルム２である光学異方性フィルムＡ～Ｆの作製＞
（光学異方性フィルムＡの作製）
　アセチル基置換度１．３０、プロピオニル基置換度１．２５、総アシル基置換度２．５５のセルロースエステルに対し、一般式（１）の化合物Ｎｏ．６１を８質量部、Ｉｒｇａｎｏｘ１０１０（チバ・ジャパン株式会社製）０．５質量部、アデカスタイプＰＥＰ－３６（株式会社ＡＤＥＫＡ製）０．０８質量部、ＳｕｍｉｌｉｚｅｒＧＳ（住友化学株式会社製）０．２質量部、シーホスターＫＥＰ－３０（株式会社日本触媒製）０．０７質量部を真空ナウターミキサーで８０℃、１Ｔｏｒｒで３時間混合しながらさらに乾燥した。 A coating solution is applied at a film thickness of 100 nm on the actinic radiation curable resin layer or the high refractive index layer by using a die coater method, dried at 120 ° C. for 1 minute, and then irradiated with ultraviolet rays to obtain a refractive index of 1.37. The low refractive index layer was formed.
<Preparation of Optically Anisotropic Films A to F that are Polarizing Plate Protective Films 2>
(Preparation of optically anisotropic film A)
For cellulose esters having an acetyl group substitution degree of 1.30, a propionyl group substitution degree of 1.25, and a total acyl group substitution degree of 2.55, compound No. 1 of general formula (1) was used. 61 parts 8 parts by mass, Irganox 1010 (Ciba Japan Co., Ltd.) 0.5 parts by mass, Adekas type PEP-36 (Adeka Co., Ltd.) 0.08 parts by mass, Sumilizer GS (Sumitomo Chemical Co., Ltd.) 0.2 parts by mass Then, 0.07 part by mass of Seahoster KEP-30 (manufactured by Nippon Shokubai Co., Ltd.) was further dried with a vacuum nauter mixer at 80 ° C. and 1 Torr for 3 hours.
　得られた混合物を、二軸式押出機を用いて２３５℃で溶融混合しペレット化した。ペレット（水分率５０ｐｐｍ）を、金属製のリーフディスク形状のフィルター、またギアポンプを組み合わせた、１軸押出機を用いてＴダイから表面温度が１２５℃の第１冷却ロール上に溶融温度２５０℃でフィルム状に溶融押し出し、幅１．０ｍのキャストフィルムを毎分１５ｍの長さで得た。 The obtained mixture was melt-mixed at 235 ° C. using a twin-screw extruder and pelletized. Pellets (moisture content of 50 ppm) were melted at a melting temperature of 250 ° C. on a first cooling roll having a surface temperature of 125 ° C. from a T-die using a single screw extruder combined with a metal leaf disk filter and a gear pump. The film was melt extruded and a cast film having a width of 1.0 m was obtained at a length of 15 m / min.
　この際、第１冷却ロール上でフィルムを２ｍｍ厚の金属表面を有する弾性タッチロールで押圧した。さらに予熱ゾーン、延伸ゾーン、保持ゾーン、冷却ゾーンを有するテンターにて、幅手方向に１５５℃で延伸倍率５５％で延伸速度２００％／ｍｉｎで延伸したあと、３０℃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、厚さ４０μｍのフィルムを得た。 At this time, the film was pressed on the first cooling roll with an elastic touch roll having a 2 mm thick metal surface. Further, in a tenter having a preheating zone, a stretching zone, a holding zone, and a cooling zone, the film was stretched in the width direction at 155 ° C. at a stretching ratio of 55% and a stretching speed of 200% / min, and then cooled to 30 ° C. It was opened and the clip gripping part was cut off to obtain a film having a thickness of 40 μm.
　得られた、光学異方性フィルムはＲｏが５０ｎｍ、Ｒｔが１３０ｎｍ、Ｒｔのばらつきは７ｎｍであった。
（光学異方性フィルムＢの作製）
　光学異方性フィルムＡの作製においてセルロースエステルを、アセチル基置換度１．２０、プロピオニル基置換度１．２５、総アシル基置換度２．４５のセルロースエステルに変更し、さらに幅手方向の延伸条件を温度１５０℃、延伸倍率３０％、延伸速度７００％で延伸した以外は同様にして、光学異方性フィルムＢを作製した。得られた、光学異方性フィルムはＲｏが５０ｎｍ、Ｒｔが１３２ｎｍ、Ｒｔのばらつきは１２ｎｍであった。
（光学異方性フィルムＣの作製）
　光学異方性フィルムＡの作製において、第１冷却ロール温度を１１０℃にし毎分３０ｍの速さでフィルムを作製し、さらに幅手方向の延伸条件を温度１６０℃、延伸倍率５０％、延伸速度７００％で延伸した以外は同様にして、光学異方性フィルムＣを得た。得られた、光学異方性フィルムはＲｏが５１ｎｍ、Ｒｔが１２８ｎｍ、Ｒｔのばらつきは１８ｎｍであった。
（光学異方性フィルムＤの作製）
　アセチル基置換度０．３５、プロピオニル基置換度２．４７、総アシル基置換度２．８２のセルロースエステルに対し、化合物Ｂを０．５質量部、ＳｕｍｉｌｉｚｅｒＧＰ（住友化学株式会社製）０．１質量部、二酸化珪素部粒子（アエロジルＲ９７２Ｖ）０．０５質量部を真空ナウターミキサーで８０℃、１Ｔｏｒｒで３時間混合しながらさらに乾燥した。 The obtained optically anisotropic film had Ro of 50 nm, Rt of 130 nm, and Rt variation of 7 nm.
(Preparation of optically anisotropic film B)
In the production of the optically anisotropic film A, the cellulose ester is changed to a cellulose ester having an acetyl group substitution degree of 1.20, a propionyl group substitution degree of 1.25, and a total acyl group substitution degree of 2.45, and further stretching in the width direction. An optically anisotropic film B was prepared in the same manner except that the film was stretched at a temperature of 150 ° C., a stretching ratio of 30%, and a stretching speed of 700%. The obtained optically anisotropic film had Ro of 50 nm, Rt of 132 nm, and Rt variation of 12 nm.
(Preparation of optically anisotropic film C)
In the production of the optical anisotropic film A, the first cooling roll temperature was set to 110 ° C., and the film was produced at a speed of 30 m / min. Further, the stretching condition in the width direction was 160 ° C., the stretching ratio was 50%, the stretching speed. An optically anisotropic film C was obtained in the same manner except that the film was stretched at 700%. The obtained optically anisotropic film had Ro of 51 nm, Rt of 128 nm, and Rt variation of 18 nm.
(Preparation of optically anisotropic film D)
0.5 parts by mass of Compound B, Sumilizer GP (manufactured by Sumitomo Chemical Co., Ltd.) 0.1 with respect to cellulose ester having an acetyl group substitution degree of 0.35, a propionyl group substitution degree of 2.47, and a total acyl group substitution degree of 2.82 Part by mass and 0.05 part by mass of silicon dioxide part particles (Aerosil R972V) were further dried with mixing in a vacuum nauter mixer at 80 ° C. and 1 Torr for 3 hours.
　得られた混合物を二軸式押出機を用いて２３５℃で溶融混合しペレット化した。ペレット（水分率５０ｐｐｍ）を、金属製のリーフディスク形状のフィルター、またギアポンプを組み合わせた、１軸押出機を用いてＴダイから表面温度が１０５℃の第１冷却ロール上に溶融温度２２５℃でフィルム状に溶融押し出し、幅１．０ｍのキャストフィルムを毎分１５ｍの長さで得た。 The obtained mixture was melt-mixed at 235 ° C. using a twin-screw extruder and pelletized. Pellets (moisture content of 50 ppm) were melted at a temperature of 225 ° C. on a first cooling roll having a surface temperature of 105 ° C. from a T die using a single screw extruder combined with a metal leaf disk filter and a gear pump. The film was melt extruded and a cast film having a width of 1.0 m was obtained at a length of 15 m / min.
　この際、第１冷却ロール上でフィルムを２ｍｍ厚の金属表面を有する弾性タッチロールで押圧した。 At this time, the film was pressed on the first cooling roll with an elastic touch roll having a 2 mm thick metal surface.
　さらに予熱ゾーン、延伸ゾーン、保持ゾーン、冷却ゾーンを有するテンターにて、幅手方向に１２８℃で延伸倍率４５％で延伸速度２００％／ｍｉｎで延伸したあと、３０℃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、厚さ４０μｍのフィルムを得た。 Furthermore, in a tenter having a preheating zone, a stretching zone, a holding zone, and a cooling zone, the film was stretched at 128 ° C. in the width direction at a stretching ratio of 45% and a stretching rate of 200% / min, and then cooled to 30 ° C. It was opened and the clip gripping part was cut off to obtain a film having a thickness of 40 μm.
　得られた、光学異方性フィルムはＲｏが４９ｎｍ、Ｒｔが１４１ｎｍ、Ｒｔのばらつきは８ｎｍであった。
化合物Ｂ The obtained optically anisotropic film had Ro of 49 nm, Rt of 141 nm, and Rt variation of 8 nm.
Compound B
Figure JPOXMLDOC01-appb-C000026
Figure JPOXMLDOC01-appb-C000026
（光学異方性フィルムＥの作製）
　ノルボルネン系樹脂（日本ゼオン社製、ＺＥＯＮＯＲ１４２０Ｒ）のペレットを７０℃で２時間乾燥して水分を除去したあと、リーフディスク形状のポリマーフィルター、またギアポンプを組み合わせた、１軸押出機を用いてＴダイから表面温度が１０５℃の冷却ロール上に溶融温度２４５℃でフィルム状に溶融押し出し、幅１．０ｍのキャストフィルムを毎分１５ｍの長さで得た。 (Preparation of optically anisotropic film E)
After drying the pellets of norbornene resin (ZEONOR1420R, manufactured by Nippon Zeon Co., Ltd.) at 70 ° C. for 2 hours to remove moisture, a T-die using a single-screw extruder combined with a leaf disk-shaped polymer filter and gear pump The film was melt extruded onto a cooling roll having a surface temperature of 105 ° C. at a melting temperature of 245 ° C. to obtain a cast film having a width of 1.0 m at a length of 15 m / min.
　さらに予熱ゾーン、延伸ゾーン、保持ゾーン、冷却ゾーンを有するテンターにて、幅手方向に１４３℃で、延伸倍率７５％で延伸速度１５０％／ｍｉｎで延伸したあと、３０℃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、厚さ４０μｍのフィルムを得た。 In a tenter having a preheating zone, stretching zone, holding zone, and cooling zone, the film was stretched at 143 ° C in the width direction, with a stretching ratio of 75% and a stretching speed of 150% / min, and then cooled to 30 ° C, and then clipped. And the clip gripping part was cut off to obtain a film having a thickness of 40 μm.
　得られた、光学異方性フィルムはＲｏが４８ｎｍ、Ｒｔが１３８ｎｍ、Ｒｔのばらつきは７ｎｍであった。
（比較光学異方性フィルムＦの作製）
　ポリプロピレン系樹脂（出光石油化学社製　Ｆ７０４）を７０℃で２時間乾燥して水分を除去したあと、リーフディスク形状のポリマーフィルター、またギアポンプを組み合わせた、１軸押出機を用いてＴダイから表面温度が１０５℃の冷却ロール上に溶融温度２４０℃でフィルム状に溶融押し出し、幅１．０ｍのキャストフィルムを毎分１５ｍの長さで得た。 The obtained optically anisotropic film had Ro of 48 nm, Rt of 138 nm, and Rt variation of 7 nm.
(Preparation of comparative optical anisotropic film F)
Polypropylene resin (F704, manufactured by Idemitsu Petrochemical Co., Ltd.) was dried at 70 ° C. for 2 hours to remove moisture, and then surfaced from the T die using a single screw extruder combined with a leaf disk-shaped polymer filter and gear pump. A cast film having a width of 1.0 m was obtained at a length of 15 m / min on a cooling roll having a temperature of 105 ° C. and melt-extruded into a film at a melting temperature of 240 ° C.
　さらに予熱ゾーン、延伸ゾーン、保持ゾーン、冷却ゾーンを有するテンターにて、幅手方向に１４０℃で、延伸倍率６５％で延伸速度１５０％／ｍｉｎで延伸したあと、３０℃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、厚さ４０μｍのフィルムを得た。 Furthermore, in a tenter having a preheating zone, a stretching zone, a holding zone, and a cooling zone, the film is stretched at 140 ° C. in the width direction at a stretching ratio of 65% and a stretching speed of 150% / min, then cooled to 30 ° C., and then clipped. And the clip gripping part was cut off to obtain a film having a thickness of 40 μm.
　得られた、光学異方性フィルムはＲｏが５０ｎｍ、Ｒｔが１４３ｎｍ、Ｒｔのばらつきは９ｎｍであった。
＜偏光板および液晶表示装置の作製＞
　（アルカリケン化処理）
　上記作製した保護フィルム１０１～１２６と光学異方性フィルムＡ、Ｂ、Ｃ、Ｄ、Ｅ、Ｆは下記に記載するアルカリケン化処理した。 The obtained optically anisotropic film had Ro of 50 nm, Rt of 143 nm, and Rt variation of 9 nm.
<Production of polarizing plate and liquid crystal display device>
(Alkaline saponification treatment)
The produced protective films 101 to 126 and the optically anisotropic films A, B, C, D, E, and F were subjected to alkali saponification treatment as described below.
　　ケン化工程　　２．５Ｍ－ＮａＯＨ　５０℃　　９０秒
　　水洗工程　　　水　　　　　　　　　３０℃　　４５秒
　　中和工　　　　１０質量部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。 Saponification step 2.5M-NaOH 50 ° C 90 seconds Water washing step Water 30 ° C 45 seconds Neutralizer 10 parts HCl 30 ° C 45 seconds Water washing step Water 30 ° C 45 seconds After saponification treatment, water washing, neutralization, water washing in this order And then dried at 80 ° C.
　〈偏光子の作製と貼り合わせ〉
　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倍に製膜方向に延伸して偏光子を作った。 <Production and bonding of polarizers>
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 film forming direction 6 times at 50 ° C. to produce a polarizer.
　次に、ポリビニルアルコール系の接着剤を用いて、偏光子の透過軸とフィルムの面内遅相軸が平行になるように偏光子の片面に保護フィルム、反対面に光学異方性フィルムを表２に示す組み合わせになるように貼り合わせ偏光板１０１～１２６を得た。
＜液晶表示装置の作製＞
　得られた偏光板はソニー株式会社製３２型液晶テレビ“ＢＲＡＶＩＡ”ＫＤＬ－３２Ｊ５０００にあらかじめ貼合されていた偏光板を注意深く剥がし、もともと貼ってあった偏光板の透過軸にあわせ、光学異方性フィルム側を液晶セル側に粘着剤を介して貼り付け液晶表示装置を作製した。 Next, using a polyvinyl alcohol-based adhesive, display a protective film on one side of the polarizer and an optically anisotropic film on the other side so that the transmission axis of the polarizer and the in-plane slow axis of the film are parallel. Bonded polarizing plates 101 to 126 were obtained so that the combinations shown in 2 were obtained.
<Production of liquid crystal display device>
The obtained polarizing plate was carefully peeled off from the polarizing plate previously bonded to Sony's 32-inch LCD TV “BRAVIA” KDL-32J5000, and aligned with the transmission axis of the polarizing plate originally applied to obtain optical anisotropy. A liquid crystal display device was produced by attaching the film side to the liquid crystal cell side through an adhesive.
　硬度ムラ、平面性、光漏れ、色むらについての評価結果を表４に示す。
＜評価＞
　〈硬度ムラ〉
　各偏光板を６０℃９０％ＲＨの条件で１００時間放置し、２３℃５５％ＲＨに戻し１００時間を経過したあとに、異なる硬度の鉛筆を用い、１ｋｇ荷重下でＪＩＳ　Ｋ５４００で示される試験法に基づき硬度試験を行った。各々の偏光板の反射防止フィルムの幅手方向に１０分割し、各位置での鉛筆硬度を測定し、下記の評価基準で評価した。 Table 4 shows the evaluation results of hardness unevenness, flatness, light leakage, and color unevenness.
<Evaluation>
<Hardness unevenness>
Each polarizing plate is allowed to stand for 100 hours at 60 ° C. and 90% RH, and after returning to 23 ° C. and 55% RH for 100 hours, using a pencil with a different hardness, a test method shown in JIS K5400 under a 1 kg load. The hardness test was conducted based on the above. Each polarizing plate was divided into 10 in the width direction of the antireflection film, the pencil hardness at each position was measured, and evaluated according to the following evaluation criteria.
　◎：各位置での表面硬度にムラが全く認められない
　○：各位置での表面硬度にムラが僅かに認められる
　×：各位置での表面硬度にムラが認められる
　硬度ムラは○以上の評価であれば、実用上問題ない。 A: No unevenness is observed in the surface hardness at each position. O: A slight unevenness is observed in the surface hardness at each position. X: An unevenness is observed in the surface hardness at each position. If so, there is no practical problem.
　〈液晶表示装置での平面性〉
　各液晶表示装置について、６０℃９０％ＲＨの条件で１００時間放置し、２３℃５５％ＲＨに戻し１００時間を経過したあとに、電源をオフにして液晶表示装置の表面を暗室にて３波長蛍光灯の反射光での目視から、下記評価基準で評価した。 <Flatness in liquid crystal display devices>
Each liquid crystal display device was left for 100 hours at 60 ° C. and 90% RH, returned to 23 ° C. and 55% RH, and after 100 hours had elapsed, the power was turned off and the surface of the liquid crystal display device was placed in a dark room for 3 wavelengths. From the visual observation with the reflected light of a fluorescent lamp, the following evaluation criteria were used.
　◎：干渉縞が認められない
　○：干渉縞が僅かに認められる
　×：干渉縞がクッキリと現れる
　平面性は○以上の評価であれば、実用上問題ない。 A: Interference fringes are not recognized. O: Interference fringes are slightly recognized. X: Interference fringes clearly appear. If the flatness is an evaluation of B or higher, there is no practical problem.
　〈液晶表示装置での光漏れ〉
　各液晶表示装置について、６０℃９０％ＲＨの条件で１００時間放置し、２３℃５５％ＲＨに戻し１００時間を経過したあとに、液晶表示装置を黒表示して画面内の光漏れを目視評価し、下記基準で評価した。 <Light leakage in liquid crystal display>
Each liquid crystal display device was left for 100 hours at 60 ° C. and 90% RH, returned to 23 ° C. and 55% RH, and after 100 hours had elapsed, the liquid crystal display device was displayed in black, and light leakage in the screen was visually evaluated. And evaluated according to the following criteria.
　◎：光漏れがまったくない
　○：弱い光漏れが１～２箇所ある
　△：強い光漏れが１～２箇所ある
　×：強い光漏れが３箇所以上ある。 A: There is no light leakage. O: There are 1 to 2 weak light leaks. Δ: There are 1 to 2 strong light leaks. X: There are 3 or more strong light leaks.
　光漏れは○以上の評価であれば、実用上問題ない。 光 Light leakage is not a problem for practical use as long as the evaluation is ○ or higher.
　〈液晶表示装置での色ムラ〉
　各液晶表示装置について、６０℃９０％ＲＨの条件で１００時間放置し、２３℃５５％ＲＨに戻し１００時間を経過したあとに、液晶表示装置を暗室内で明表示して正面より目視観察し、下記基準で評価した。 <Color unevenness in liquid crystal display devices>
Each liquid crystal display device is left for 100 hours at 60 ° C. and 90% RH, and after returning to 23 ° C. and 55% RH for 100 hours, the liquid crystal display device is brightly displayed in a dark room and visually observed from the front. The evaluation was based on the following criteria.
　○：全体的に均一であり色がない
　×：画面上に僅かに色として認められる部分がある ○: Uniform overall and no color ×: Some parts of the screen are recognized as colors
Figure JPOXMLDOC01-appb-T000027
Figure JPOXMLDOC01-appb-T000027
　表４に記載の通り、本発明に関わる試料では、硬度むらがほとんどなく、平面性にも優れていることがわかった。また光漏れおよび色むらがなく視認性に優れていることがわかった。一方、本発明以外の試料では、硬度むらあるいは平面性が大きく劣り、さらに光漏れあるいは色むらの視認性が劣る結果となった。 As shown in Table 4, the samples according to the present invention were found to have almost no hardness unevenness and excellent flatness. It was also found that there was no light leakage and no color unevenness and excellent visibility. On the other hand, in samples other than the present invention, the hardness unevenness or flatness was greatly inferior, and the visibility of light leakage or color unevenness was inferior.

Claims (4)

  1. 　偏光子と、この偏光子を挟む２枚の偏光板保護フィルム１および２とからなる偏光板において、前記偏光板保護フィルム１は、下記式（Ａ１）および（Ａ２）を同時に満足し、含有溶媒量が０．０１質量％以下であり、１００℃における製膜方向または幅手方向の少なくとも一方の音速が１．６～２．２ｋｍ／ｓであるセルロースエステルフィルムであり、前記偏光板保護フィルム２は、その厚み方向のレターデーションＲｔのばらつきが１０ｎｍ以下である光学異方性フィルムであることを特徴とする偏光板。
    　　式（Ａ１）　２．０≦Ｘ＋Ｙ≦３．０
    　　式（Ａ２）　１．０≦Ｙ≦２．５
    （式中、Ｘはセルロースエステルのアセチル基の置換度、Ｙはプロピオニル基またはブチリル基の置換度を表す。）     In the polarizing plate comprising a polarizer and two polarizing plate protective films 1 and 2 sandwiching the polarizer, the polarizing plate protective film 1 satisfies the following formulas (A1) and (A2) at the same time, and contains a solvent The polarizing plate protective film 2 is a cellulose ester film having an amount of 0.01% by mass or less and a sound velocity of at least one of a film forming direction and a width direction at 100 ° C. of 1.6 to 2.2 km / s. Is an optically anisotropic film having a variation in retardation Rt in the thickness direction of 10 nm or less.
    Formula (A1) 2.0 ≦ X + Y ≦ 3.0
    Formula (A2) 1.0 ≦ Y ≦ 2.5
    (In the formula, X represents the degree of substitution of the acetyl group of the cellulose ester, and Y represents the degree of substitution of the propionyl group or butyryl group.)
  2. 　前記音速が、０．９≦音速（ＴＤ）／音速（ＭＤ）≦１．１の関係となることを特徴とする請求の範囲第１項に記載の偏光板。
    （ＭＤは製膜方向、ＴＤは幅手方向を表す）     2. The polarizing plate according to claim 1, wherein the speed of sound is 0.9 ≦ sound speed (TD) / sound speed (MD) ≦ 1.1.
    (MD represents the film forming direction and TD represents the width direction)
  3. 　請求の範囲第１項または第２項に記載の偏光板に使用する偏光板保護フィルムの製造方法であって該偏光板保護フィルムは、溶融製膜によって製膜され、かつフィルムの製膜方向に下記式（Ｂ）で表される延伸速度が１０００％／ｍｉｎ～３００００％／ｍｉｎで延伸することにより得られることを特徴とする請求の範囲第１項または第２項に記載の偏光板に使用する偏光板保護フィルムの製造方法。
    　式（Ｂ）
    　延伸速度（％／ｍｉｎ）＝｛（延伸後寸法／延伸前寸法）－１｝×１００（％）／延伸に要する時間（ｍｉｎ）     It is a manufacturing method of the polarizing plate protective film used for the polarizing plate of Claim 1 or Claim 2, Comprising: This polarizing plate protective film is formed into a film in the film forming direction by melt film formation. The stretching rate represented by the following formula (B) is obtained by stretching at 1000% / min to 30000% / min, used for the polarizing plate according to claim 1 or 2 A method for producing a polarizing plate protective film.
    Formula (B)
    Stretching speed (% / min) = {(dimension after stretching / dimension before stretching) -1} × 100 (%) / time required for stretching (min)
  4. 　請求の範囲第１項または第２項に記載の偏光板を備え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 1 or 2.
PCT/JP2009/050029 2008-03-26 2009-01-06 Polarizer, process for producing polarizer-protecting film, and liquid-crystal display WO2009119122A1 (en)

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