JP2007310260A - Polarizing plate protective film and polarizing plate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizing plate protective film having polarization property and using the inclusion effect of amylose, and a polarizing plate having high durability. <P>SOLUTION: The polarizing plate protective film comprises an amylose ester and a cellulose ester and has been dyed with an iodine solution. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polarizing plate protective film and a polarizing plate.

  Conventionally, a polarizing plate used for a liquid crystal display device uses a polyvinyl alcohol film dyed with iodine as a polarizer, and a protective film such as a cellulose ester film is bonded to both sides of the polarizer. In general, a iodine-stained polarizer is superior in polarization characteristics as compared to a polarizer dyed with a dichroic dye, but is said to be inferior in durability. However, recently, liquid crystal display devices are used in various applications, so they may be used for a long time in a high-temperature and high-humidity environment. Further high durability is required.

  In addition, there is a high demand for thinning and lightening the polarizing plate, and as one means there is a demand for thinning the protective film for the polarizing plate. However, it has been clarified that there are various harmful effects by simply thinning the protective film for polarizing plate. As one of them, there is an influence on moisture permeability (moisture permeability). For example, as the protective film for a polarizing plate becomes thinner, the moisture permeability becomes higher, and as a result, the durability of the polarizing plate decreases. Several means for improving the moisture permeability have been proposed.

For example, a retardation film with improved moisture permeability has been proposed in order to obtain a display device having stable display quality over time and excellent productivity. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 2002-14230

  Accordingly, an object of the present invention is to provide a polarizing plate protective film and a polarizing plate that suppress deterioration of polarization characteristics under a high-temperature and high-humidity environment, which is a drawback of conventional polarizing plates, and have high durability.

  The above object of the present invention is achieved by the following configurations.

  1. A polarizing plate protective film comprising amylose ester and cellulose ester and dyed with an iodine solution.

  2. 2. The polarizing plate protective film as described in 1 above, wherein the amylose ester has a total acyl group substitution degree in the range of 0.1 to 2.5.

  3. A polarizing plate having the polarizing plate protective film according to 1 or 2 on at least one surface of a polarizer.

  INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a polarizing plate protective film having high durability and a polarizing plate that suppresses deterioration of polarization characteristics under a high temperature and high humidity environment, which is a defect of a conventional polarizing plate.

  The best mode for carrying out the present invention will be described in detail below, but the present invention is not limited thereto.

  As a result of intensive studies in view of the above problems, the present inventors have obtained polarizing light in a high-temperature and high-humidity environment by using a polarizing plate protective film containing an amylose ester and a cellulose ester and dyed with an iodine solution. It has been found that a polarizing plate protective film and a polarizing plate capable of suppressing deterioration of characteristics and having high durability can be obtained, and the present invention has been made.

  Hereinafter, each element of the present invention will be described in detail.

[Amylose ester]
Examples of the amylose used as a raw material for the amylose ester used in the present invention include those contained in natural starch and those synthesized by enzymatic synthesis, but those synthesized by enzymatic synthesis are preferred. There are several known methods for synthesizing amylose using an enzyme, such as a starch enzymatic degradation method and a method using amylosucrase, but a method using phosphorylase is particularly preferred.

  Phosphorylase is an enzyme that catalyzes the phosphorolysis reaction, and there are several methods using phosphorylase. For example, glucan phosphorylase (α-glucan phosphorylase, EC 2.4.1.1; usually referred to as phosphorylase) is allowed to act on the glucose-1-phosphate glucosyl group as a primer to maltoheptaose as a primer. There are a transfer method, a method in which sucrose is used as a substrate and malto-oligosaccharide is used as a primer, and sucrose phosphorylase and glucan phosphorylase are simultaneously reacted in the presence of inorganic phosphate to synthesize amylose.

  As a method for synthesizing amylose ester used in the present invention, amylose is generally reacted with acid anhydride, organic acid, acid chloride, ketene or other esterification reagent in various solvents. Representative synthesis methods are listed below, but are not limited thereto.

  Specifically, amylose is dissolved in dimethyl sulfoxide and esterified by adding sodium carbonate and vinyl acetate, acetic anhydride, propionic anhydride, or butyric anhydride. After the reaction, water can be added to the amylose ester solution to separate the amylose ester, and the amylose ester can be obtained by washing. By changing the ratio of sodium carbonate and vinyl acetate or acetic anhydride, amylose esters with various degrees of substitution can be obtained.

  The amylose ester used in the present invention has an acyl group having 2 to 4 carbon atoms as a substituent, and when the substitution degree of the acetyl group is X and the substitution degree of the propionyl group or butyryl group is Y, the following formula ( Amylose esters that simultaneously satisfy I) and (II) are preferred.

Formula (I) 0.1 ≦ X + Y ≦ 2.5
Formula (II) 0 ≦ X ≦ 2.5
Among them, an amylose ester (total acyl group substitution degree = X + Y) of 0.1 ≦ X ≦ 2.5 and 0 ≦ Y ≦ 1.0 is preferable.

  The degree of substitution of these acyl groups can be measured according to the method prescribed in ASTM-D817-96.

  The molecular weight of the amylose ester is preferably 10,000 to 1,000,000, more preferably 60000 to 1,000,000 in terms of weight average molecular weight (Mn). Moreover, it is preferable that Mw / Mn ratio is 1.25 or less, More preferably, it is 1.15 or less.

  Since the weight average molecular weight Mw and the number average molecular weight Mn of amylose ester can be measured using gel permeation chromatography, the number average molecular weight (Mn), the weight average molecular weight (Mw), and the Mw / Mn ratio are calculated using this. I can do it.

  The measurement conditions are as follows.

Solvent: Methylene chloride Column: Shodex K806, K805, K803 (3 used by Showa Denko Co., Ltd. connected)
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 Corp.) Mw = 100000-500 calibration curves with 13 samples were used. It is preferable that the 13 samples are substantially equally spaced.

[Cellulose ester]
Examples of the cellulose ester used in the present invention include triacetyl cellulose (TAC), diacetyl cellulose (DAC), cellulose acetate propionate (CAP), cellulose acetate butyrate (CAB), cellulose acetate phthalate, cellulose acetate trimellitate, Examples thereof include cellulose esters such as cellulose nitrate.

  The cellulose as a raw material for the cellulose ester is not particularly limited, and examples thereof include cotton linter, wood pulp, and kenaf. In addition, the cellulose derivatives obtained from these can be used alone or in an arbitrary ratio, but it is preferable to use 50% by mass or more of cotton linter.

  When the molecular weight of the cellulose ester is large, the elastic modulus is increased. However, when the molecular weight is excessively increased, the viscosity of the cellulose ester solution becomes too high, and the productivity is lowered. The molecular weight of the cellulose ester is preferably 30000-200000 in terms of number average molecular weight (Mn). The cellulose ester preferably has a Mw / Mn ratio of 4.0 or less, more preferably 1.4 to 2.3.

  Since the average molecular weight and molecular weight distribution of the cellulose ester can be measured using the above-mentioned high performance liquid chromatography, the number average molecular weight (Mn) and the mass average molecular weight (Mw) can be calculated using this, and the ratio can be calculated. .

  A preferred cellulose ester has an acyl group having 2 to 4 carbon atoms as a substituent, and when the substitution degree of the acetyl group is X and the substitution degree of the propionyl group or butyryl group is Y, the following formula (III) and It is a cellulose ester that simultaneously satisfies (IV).

Formula (III) 2.0 ≦ X + Y ≦ 3.0
Formula (IV) 0 ≦ X ≦ 3.0
Among them, a cellulose ester of 2.4 ≦ X + Y ≦ 3.0 and 2.0 ≦ X ≦ 3.0 (total acyl group substitution degree = X + Y) is preferable. The degree of substitution of these acyl groups can be measured according to the method prescribed in ASTM-D817-96. The portion not substituted with an acyl group usually exists as a hydroxyl group. These cellulose esters can be synthesized by a known method. Specifically, the cellulose acylate described in JP-A-2004-315613 [0045] to [0052] is preferably used as the cellulose ester used in the present invention.

  The mixing ratio of the amylose ester and cellulose ester according to the present invention in the film is preferably 95: 5 to 5:95, more preferably 95: 5 to 50:50.

〔solvent〕
The amylose ester and cellulose ester according to the present invention are dissolved in a solvent to form a dope, which is cast on a substrate to form a film. At this time, since it is necessary to evaporate the solvent after extrusion or casting, it is preferable to use a volatile solvent. Furthermore, the casting substrate is not dissolved. Two or more solvents may be mixed and used.

  Here, an organic solvent having good solubility in the above amylose ester and cellulose ester is referred to as a good solvent, and has a main effect on dissolution, and an organic solvent used in a large amount among them is a main (organic) solvent or It is called the main (organic) solvent.

  Examples of good solvents include ketones such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, ethers such as tetrahydrofuran (THF), 1,4-dioxane, 1,3-dioxolane, 1,2-dimethoxyethane, and the like. In addition to esters such as methyl acid, ethyl formate, methyl acetate, ethyl acetate, amyl acetate, γ-butyrolactone, methyl cellosolve, dimethylimidazolinone, dimethylformamide, dimethylacetamide, acetonitrile, dimethylsulfoxide, sulfolane, nitroethane, methylene chloride 1,3-dioxolane, THF, methyl ethyl ketone, acetone, methyl acetate and methylene chloride are preferable.

  The dope preferably contains 1 to 40% by mass of an alcohol having 1 to 4 carbon atoms in addition to the organic solvent. After casting the dope on a metal support, the solvent starts to evaporate and the ratio of alcohol increases so that the web (the name of the dope film after casting the dope of amylose ester and cellulose ester on the support). Is used as a gelling solvent to make the web strong and easy to peel from the metal support, or when these ratios are low, amylose esters of non-chlorine organic solvents and There is also a role of promoting dissolution of cellulose ester.

  Examples of the alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, tert-butanol, and propylene glycol monomethyl ether. Of these, ethanol is preferred because it has excellent dope stability, has a relatively low boiling point, good drying properties, and no toxicity. These organic solvents alone are not soluble in amylose esters and cellulose esters and are referred to as poor solvents.

  The most preferable solvent that satisfies such conditions and dissolves amylose ester and cellulose ester, which are preferable polymer compounds, at a high concentration is a mixed solvent having a ratio of methylene chloride: ethyl alcohol of 95: 5 to 80:20. . Alternatively, a mixed solvent of methyl acetate: ethyl alcohol 60:40 to 95: 5 is also preferably used.

〔Additive〕
The polarizing plate protective film of the present invention includes a plasticizer that imparts processability, flexibility, and moisture resistance to the film, an ultraviolet absorber that imparts an ultraviolet absorbing function, an antioxidant that prevents deterioration of the film, and slipperiness to the film. Fine particles (matting agent) for imparting a retardation, a retardation adjusting agent for adjusting the retardation of the film, and the like may be contained.

(Plasticizer)
The plasticizer is not particularly limited, but has a functional group capable of interacting with amylose ester and cellulose ester by hydrogen bonding or the like so as not to generate haze, bleed out or volatilize from the film. Is preferred.

  Examples of such functional groups include hydroxyl groups, ether groups, carbonyl groups, ester groups, carboxylic acid residues, amino groups, imino groups, amide groups, imide groups, cyano groups, nitro groups, sulfonyl groups, sulfonic acid residues, Examples thereof include a phosphonyl group and a phosphonic acid residue, and a carbonyl group, an ester group and a phosphonyl group are preferred.

  Examples of such plasticizers include phosphate ester plasticizers, phthalate ester plasticizers, trimellitic ester plasticizers, pyromellitic acid plasticizers, polyhydric alcohol plasticizers, glycolate plasticizers. Citric acid ester plasticizers, fatty acid ester plasticizers, carboxylic acid ester plasticizers, polyester plasticizers, and the like can be preferably used. Particularly, in order to obtain the effects of the present invention, polyhydric alcohols are preferable. It is to use a plasticizer and an ester plasticizer, and it is particularly preferable to contain a polyhydric alcohol ester plasticizer and an aromatic terminal ester plasticizer described later.

(Polyhydric ester plasticizer)
The polyhydric alcohol ester is composed of an ester of a dihydric or higher aliphatic polyhydric alcohol and a monocarboxylic acid, and preferably has an aromatic ring or a cycloalkyl ring in the molecule.

  The polyhydric alcohol used in the present invention is represented by the following general formula (V).

Formula (V) R _1- (OH) _n
(In the formula, R ₁ represents an n-valent organic group, and n represents a positive integer of 2 or more.)
Examples of preferred polyhydric alcohols include the following, but the present invention is not limited to these. Adonitol, arabitol, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol, 1,3- Butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, galactitol, mannitol, 3-methylpentane- Examples include 1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, xylitol, pentaerythritol, dipentaerythritol and the like.

  There is no restriction | limiting in particular as monocarboxylic acid used for polyhydric alcohol ester, Well-known aliphatic monocarboxylic acid, alicyclic monocarboxylic acid, aromatic monocarboxylic acid, etc. can be used. Use of an alicyclic monocarboxylic acid or aromatic monocarboxylic acid is preferable in terms of improving moisture permeability and retention. Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.

  As the aliphatic monocarboxylic acid, a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used. It is more preferable that it is C1-C20, and it is especially preferable that it is C1-C10. The use of acetic acid is preferred because the compatibility with the cellulose ester is increased, and it is also preferred to use a mixture of acetic acid and another monocarboxylic acid.

  Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid, tridecylic acid , Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, laccelic acid, undecylenic acid, Examples thereof include unsaturated fatty acids such as oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid.

  Examples of preferable alicyclic monocarboxylic acids include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, and derivatives thereof. Examples of preferred aromatic monocarboxylic acids include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and two or more benzene rings such as biphenylcarboxylic acid, naphthalenecarboxylic acid, and tetralincarboxylic acid. Aromatic monocarboxylic acids possessed by them, or derivatives thereof. In particular, benzoic acid is preferred.

  The molecular weight of the polyhydric alcohol ester is preferably 300 to 1500, and more preferably 350 to 750. A higher molecular weight is preferable because it is less likely to volatilize, and a lower molecular weight is preferable in terms of moisture permeability and compatibility with amylose ester. The carboxylic acid used for the polyhydric alcohol ester may be one kind or a mixture of two or more kinds. Moreover, all the OH groups in the polyhydric alcohol may be esterified, or a part of the OH groups may be left as they are. The specific compound of a polyhydric alcohol ester is shown below.

  The content of the polyhydric alcohol ester plasticizer is preferably 1 to 15% by mass, particularly preferably 3 to 10% by mass in the amylose ester and cellulose ester.

(Ester plasticizer)
The ester plasticizer is not particularly limited, but an ester plasticizer having an aromatic ring or a cycloalkyl ring in the molecule can be preferably used. Although it does not specifically limit as a preferable ester plasticizer, For example, the aromatic terminal ester plasticizer represented by the following general formula (VI) is preferable.

Formula (VI) B- (GA) _n -GB
(In the formula, B is a benzene monocarboxylic acid residue, G is an alkylene glycol residue having 2 to 12 carbon atoms, an aryl glycol residue having 6 to 12 carbon atoms, or an oxyalkylene glycol residue having 4 to 12 carbon atoms, A represents an alkylene dicarboxylic acid residue having 4 to 12 carbon atoms or an aryl dicarboxylic acid residue having 6 to 12 carbon atoms, and n represents an integer of 1 or more.)
A benzene monocarboxylic acid residue represented by B of an ester plasticizer, an alkylene glycol residue, an oxyalkylene glycol residue or an aryl glycol residue represented by G, and an alkylene dicarboxylic acid residue represented by A Or it is comprised from an aryl dicarboxylic acid residue, and is obtained by reaction similar to a normal polyester plasticizer.

  Examples of the benzene monocarboxylic acid component of the ester plasticizer used in the present invention include benzoic acid, para-tert-butylbenzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethylbenzoic acid, ethylbenzoic acid, and normalpropyl benzoic acid. There are acid, aminobenzoic acid, acetoxybenzoic acid and the like, and these can be used as one kind or a mixture of two or more kinds, respectively.

  Examples of the alkylene glycol component having 2 to 12 carbon atoms of the ester plasticizer used in the present invention include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3- Butanediol, 1,2-propanediol, 2-methyl 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol) ), 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3 -Methyl-1,5-pentanediol 1,6-hexanediol, 2,2,4-trimethyl 1,3-pentanediol, -Ethyl 1,3-hexanediol, 2-methyl 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-octadecanediol, and the like. Or it is used as a mixture of two or more. In particular, alkylene glycols having 2 to 12 carbon atoms are particularly preferable because of excellent compatibility with amylose esters.

  Examples of the oxyalkylene glycol component having 4 to 12 carbon atoms of the aromatic terminal ester include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol. Or it can be used as a mixture of two or more.

  Examples of the alkylene dicarboxylic acid component having 4 to 12 carbon atoms of the aromatic terminal ester include succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid. These are used as one kind or a mixture of two or more kinds. Examples of the arylene dicarboxylic acid component having 6 to 12 carbon atoms include phthalic acid, terephthalic acid, isophthalic acid, 1,5 naphthalene dicarboxylic acid, and 1,4 naphthalene dicarboxylic acid.

  The ester plasticizer used in the present invention has a number average molecular weight of preferably 300 to 1500, more preferably 400 to 1000. The acid value is preferably 0.5 mgKOH / g or less, the hydroxyl value is 25 mgKOH / g or less, more preferably the acid value is 0.3 mgKOH / g or less, and the hydroxyl value is 15 mgKOH / g or less.

  Hereinafter, synthesis examples of aromatic terminal ester plasticizers preferably used in the present invention will be shown.

<Sample No. 1 (Aromatic terminal ester sample)>
A reaction vessel was charged with 410 parts of phthalic acid, 610 parts of benzoic acid, 737 parts of dipropylene glycol, and 0.40 part of tetraisopropyl titanate as a catalyst. While refluxing the monohydric alcohol, heating was continued at 130 to 250 ° C. until the acid value became 2 or less, and water produced was continuously removed. Next, the distillate is removed under reduced pressure at 200 to 230 ° C. under a reduced pressure of 1.33 × 10 ⁴ Pa to 4 × 10 ² Pa or less, and then filtered to filter the aromatic terminal ester plastic having the following properties: An agent was obtained.

Viscosity (25 ° C., mPa · s); 43400
Acid value: 0.2
<Sample No. 2 (Aromatic terminal ester sample)>
Sample No. 1 was used except that 410 parts of phthalic acid, 610 parts of benzoic acid, 341 parts of ethylene glycol, and 0.35 part of tetraisopropyl titanate as a catalyst were used in the reaction vessel. In the same manner as in Example 1, an aromatic terminal ester having the following properties was obtained.

Viscosity (25 ° C., mPa · s); 31000
Acid value: 0.1
<Sample No. 3 (Aromatic terminal ester sample)>
Sample No. 1 was used except that 410 parts of phthalic acid, 610 parts of benzoic acid, 418 parts of 1,2-propanediol, and 0.35 part of tetraisopropyl titanate as the catalyst were used in the reaction vessel. In the same manner as in Example 1, an aromatic terminal ester having the following properties was obtained.

Viscosity (25 ° C., mPa · s); 38000
Acid value: 0.05
<Sample No. 4 (Aromatic terminal ester sample)>
Sample No. 4 was used except that 410 parts of phthalic acid, 610 parts of benzoic acid, 418 parts of 1,3-propanediol, and 0.35 part of tetraisopropyl titanate as a catalyst were used in the reaction vessel. In the same manner as in Example 1, an aromatic terminal ester having the following properties was obtained.

Viscosity (25 ° C., mPa · s); 37000
Acid value: 0.05
Although the specific compound of the aromatic terminal ester plasticizer which concerns on this invention below is shown, this invention is not limited to this.

(Other plasticizers)
The polyvalent carboxylic acid plasticizer useful in the present invention comprises a divalent or higher, preferably 2-20 valent polyvalent carboxylic acid and an alcohol ester. The aliphatic polyvalent carboxylic acid is preferably 2 to 20 valent, and in the case of an aromatic polyvalent carboxylic acid or an alicyclic polyvalent carboxylic acid, it is preferably 3 to 20 valent.

  The polyvalent carboxylic acid used in the present invention is represented by the following general formula (Y).

Formula (Y) R ₅ (COOH) _m (OH) _n
(However, R ₅ is an (m + n) -valent organic group, m is a positive integer of 2 or more, n is an integer of 0 or more, a COOH group is a carboxyl group, and an OH group is an alcoholic or phenolic hydroxyl group.)
Examples of preferred polyvalent carboxylic acids include the following, but the present invention is not limited to these. Trivalent or higher aromatic polyvalent carboxylic acids such as trimellitic acid, trimesic acid, pyromellitic acid or derivatives thereof, succinic acid, adipic acid, azelaic acid, sebacic acid, oxalic acid, fumaric acid, maleic acid, tetrahydrophthal An aliphatic polyvalent carboxylic acid such as an acid, an oxypolyvalent carboxylic acid such as tartaric acid, tartronic acid, malic acid and citric acid can be preferably used. In particular, it is preferable to use an oxypolycarboxylic acid from the viewpoint of improving the retention.

  There is no restriction | limiting in particular as alcohol used for a polyhydric carboxylic acid ester compound, Well-known alcohol and phenols can be used. For example, an aliphatic saturated alcohol or aliphatic unsaturated alcohol having a straight chain or side chain having 1 to 32 carbon atoms can be preferably used. It is more preferable that it is C1-C20, and it is especially preferable that it is C1-C10. Further, alicyclic alcohols such as cyclopentanol and cyclohexanol or derivatives thereof, aromatic alcohols such as benzyl alcohol and cinnamyl alcohol, or derivatives thereof can also be preferably used.

  When an oxypolycarboxylic acid is used as the polycarboxylic acid, the alcoholic or phenolic hydroxyl group of the oxypolycarboxylic acid may be esterified with a monocarboxylic acid. Examples of preferred monocarboxylic acids include the following, but the present invention is not limited thereto.

  As the aliphatic monocarboxylic acid, a fatty acid having a straight chain or a side chain having 1 to 32 carbon atoms can be preferably used. It is more preferable that it is C1-C20, and it is especially preferable that it is C1-C10.

  Preferred aliphatic monocarboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, 2-ethyl-hexanecarboxylic acid, undecylic acid, lauric acid, tridecylic acid, Saturated fatty acids such as myristic acid, pentadecylic acid, palmitic acid, heptadecylic acid, stearic acid, nonadecanoic acid, arachidic acid, behenic acid, lignoceric acid, serotic acid, heptacosanoic acid, montanic acid, melicic acid, laccelic acid, undecylenic acid, olein Examples thereof include unsaturated fatty acids such as acid, sorbic acid, linoleic acid, linolenic acid, and arachidonic acid.

  Examples of preferable alicyclic monocarboxylic acids include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, and derivatives thereof.

  Examples of preferred aromatic monocarboxylic acids include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, and two or more benzene rings such as biphenylcarboxylic acid, naphthalenecarboxylic acid, and tetralincarboxylic acid. Aromatic monocarboxylic acids possessed by them, or their derivatives. Particularly preferred are acetic acid, propionic acid, and benzoic acid.

  Although there is no restriction | limiting in particular in the molecular weight of a polyhydric carboxylic acid ester compound, It is preferable that it is the range of molecular weight 300-1000, and it is more preferable that it is the range of 350-750. The larger one is preferable in terms of improvement in retention, and the smaller one is preferable in terms of moisture permeability and compatibility with cellulose ester.

  The alcohol used for the polyvalent carboxylic acid ester used in the present invention may be one kind or a mixture of two or more kinds.

  The acid value of the polyvalent carboxylic acid ester compound used in the present invention is preferably 1 mgKOH / g or less, and more preferably 0.2 mgKOH / g or less. Setting the acid value in the above range is preferable because the environmental fluctuation of the retardation is also suppressed.

  Examples of particularly preferred polyvalent carboxylic acid ester compounds are shown below, but the present invention is not limited thereto. For example, triethyl citrate, tributyl citrate, acetyl triethyl citrate (ATEC), acetyl tributyl citrate (ATBC), benzoyl tributyl citrate, acetyl triphenyl citrate, acetyl tribenzyl citrate, dibutyl tartrate, diacetyl dibutyl tartrate, Examples include tributyl trimellitic acid and tetrabutyl pyromellitic acid.

  These plasticizers can be used alone or in admixture of two or more. If the amount of the plasticizer used is less than 1% by mass relative to the amylose ester and cellulose ester, the effect of reducing the moisture permeability of the film is small, which is not preferable. If the amount exceeds 20% by mass, the plasticizer bleeds out from the film, and the film Since the physical properties of the resin deteriorate, 1 to 20% by mass is preferable. 6-16 mass% is further more preferable, Most preferably, it is 8-13 mass%.

(UV absorber)
The ultraviolet absorbing function is preferably imparted to various optical films such as a polarizing plate protective film, a retardation film, and an optical compensation film from the viewpoint of preventing deterioration of the liquid crystal. For such an ultraviolet absorbing function, a material that absorbs ultraviolet rays may be included in amylose ester and cellulose ester, or a layer having an ultraviolet absorbing function may be provided on a film made of amylose ester and cellulose ester.

  As such an ultraviolet absorber having an ultraviolet absorbing function, those having an excellent ability to absorb ultraviolet rays having a wavelength of 370 nm or less and little absorption of visible light having a wavelength of 400 nm or more are preferably used. Specific examples of preferably used ultraviolet absorbers include triazine compounds, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like. However, it is not limited to these. Moreover, the polymeric ultraviolet absorber described in JP-A-6-148430 is also preferably used.

  Specific examples of ultraviolet absorbers useful in the present invention include 2- (2′-hydroxy-5′-methyl-phenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-butyl). -Phenyl) benzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methyl-phenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butyl) -Phenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 '-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methyl-phenyl) benzotriazole, 2 , 2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2′-hydroxy -3'-tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2H-benzotriazol-2-yl) -6- (linear and side chain dodecyl) -4-methyl-phenol [TINUVIN 171], 2-octyl-3- [3-tert-butyl-4-hydroxy-5- (chloro-2H-benzotriazol-2-yl) phenyl] propionate and 2-ethylhexyl-3- [ A mixture of 3-tert-butyl-4-hydroxy-5- (5-chloro-2H-benzotriazol-2-yl) phenyl] propionate [TINUVIN 109], 2- (2H-benzotriazol-2-yl) -4,6-bis (1-methyl-1-phenylethyl) phenol [tinuvin 234], 2- (3- - butyl-5-methyl-2-hydroxyphenyl) -5-chloro - benzotriazole [Tinuvin (TINUVIN) 326] can be mentioned, and the like. In addition, any of the above-mentioned tinuvins such as tinuvin 109, tinuvin 171 and tinuvin 326 are commercially available products manufactured by Ciba Specialty Chemicals and can be preferably used.

  Specific examples of the benzophenone compounds include 2,4-dihydroxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, bis (2-methoxy-4-hydroxy- 5-benzoylphenylmethane) and the like, but is not limited thereto.

  Moreover, since the ultraviolet absorber which can be used for the retardation film of this invention is excellent also in the applicability | paintability of various coating layers, the ultraviolet absorption whose distribution coefficient described in Unexamined-Japanese-Patent No. 2000-187825 is 9.2 or more. It is preferable to use an ultraviolet absorber having a partition coefficient of 10.1 or more.

  Moreover, the polymeric ultraviolet absorber (or ultraviolet-absorbing polymer) described in JP-A-6-148430 and JP-A-2002-47357 can be preferably used. The polymer ultraviolet absorbers described in general formula (1) or general formula (2) of JP-A-6-148430 or general formulas (3), (6), and (7) of JP-A-2002-47357 are particularly preferable. Used.

  In addition, a compound having a 1,3,5-triazine ring can be preferably used as the ultraviolet absorber of the retardation film of the present invention. The compound can also be used as a retardation adjusting agent.

  Specific examples of the compound having a 1,3,5-triazine ring are shown below.

  In addition, several R shown below represents the same group.

(1) Butyl (2) 2-Methoxy-2-ethoxyethyl (3) 5-Undecenyl (4) Phenyl (5) 4-Ethoxycarbonylphenyl (6) 4-Butoxyphenyl (7) p-Biphenylyl (8) 4 -Pyridyl (9) 2-naphthyl (10) 2-methylphenyl (11) 3,4-dimethoxyphenyl (12) 2-furyl

(14) phenyl (15) 3-ethoxycarbonylphenyl (16) 3-butoxyphenyl (17) m-biphenylyl (18) 3-phenylthiophenyl (19) 3-chlorophenyl (20) 3-benzoylphenyl (21) 3 -Acetoxyphenyl (22) 3-benzoyloxyphenyl (23) 3-phenoxycarbonylphenyl (24) 3-methoxyphenyl (25) 3-anilinophenyl (26) 3-isobutyrylaminophenyl (27) 3-phenoxy Carbonylaminophenyl (28) 3- (3-ethylureido) phenyl (29) 3- (3,3-diethylureido) phenyl (30) 3-methylphenyl (31) 3-phenoxyphenyl (32) 3-hydroxyphenyl (33) 4-Ethoxycarbonylphenyl (34) 4-butoxyphenyl (35) p-biphenylyl (36) 4-phenylthiophenyl (37) 4-chlorophenyl (38) 4-benzoylphenyl (39) 4-acetoxyphenyl (40) 4-benzoyloxyphenyl ( 41) 4-phenoxycarbonylphenyl (42) 4-methoxyphenyl (43) 4-anilinophenyl (44) 4-isobutyrylaminophenyl (45) 4-phenoxycarbonylaminophenyl (46) 4- (3-ethyl (Ureido) phenyl (47) 4- (3,3-diethylureido) phenyl (48) 4-methylphenyl (49) 4-phenoxyphenyl (50) 4-hydroxyphenyl (51) 3,4-diethoxycarbonylphenyl ( 52) 3,4-dibutoxyphenyl (53) 3 -Diphenylphenyl (54) 3,4-diphenylthiophenyl (55) 3,4-dichlorophenyl (56) 3,4-dibenzoylphenyl (57) 3,4-diacetoxyphenyl (58) 3,4-dibenzoyl Oxyphenyl (59) 3,4-diphenoxycarbonylphenyl (60) 3,4-dimethoxyphenyl (61) 3,4-dianilinophenyl (62) 3,4-dimethylphenyl (63) 3,4-diphenoxy Phenyl (64) 3,4-dihydroxyphenyl (65) 2-naphthyl (66) 3,4,5-triethoxycarbonylphenyl (67) 3,4,5-tributoxyphenyl (68) 3,4,5- Triphenylphenyl (69) 3,4,5-triphenylthiophenyl (70) 3,4,5-trichlorophenyl (71) 3,4,5-tribenzoylphenyl (72) 3,4,5-triacetoxyphenyl (73) 3,4,5-tribenzoyloxyphenyl (74) 3,4,5-triphenoxycarbonylphenyl (75) 3,4,5-trimethoxyphenyl (76) 3,4,5-trianilinophenyl (77) 3,4,5-trimethylphenyl (78) 3,4,5-triphenoxyphenyl (79 ) 3,4,5-trihydroxyphenyl

(80) phenyl (81) 3-ethoxycarbonylphenyl (82) 3-butoxyphenyl (83) m-biphenylyl (84) 3-phenylthiophenyl (85) 3-chlorophenyl (86) 3-benzoylphenyl (87) 3 -Acetoxyphenyl (88) 3-benzoyloxyphenyl (89) 3-phenoxycarbonylphenyl (90) 3-methoxyphenyl (91) 3-anilinophenyl (92) 3-isobutyrylaminophenyl (93) 3-phenoxy Carbonylaminophenyl (94) 3- (3-ethylureido) phenyl (95) 3- (3,3-diethylureido) phenyl (96) 3-methylphenyl (97) 3-phenoxyphenyl (98) 3-hydroxyphenyl (99) 4-Ethoxycarbonylphenyl (100) 4-butoxyphenyl (101) p-biphenylyl (102) 4-phenylthiophenyl (103) 4-chlorophenyl (104) 4-benzoylphenyl (105) 4-acetoxyphenyl (106) 4-benzoyloxyphenyl ( 107) 4-phenoxycarbonylphenyl (108) 4-methoxyphenyl (109) 4-anilinophenyl (110) 4-isobutyrylaminophenyl (111) 4-phenoxycarbonylaminophenyl (112) 4- (3-ethyl (Ureido) phenyl (113) 4- (3,3-diethylureido) phenyl (114) 4-methylphenyl (115) 4-phenoxyphenyl (116) 4-hydroxyphenyl (117) 3,4-diethoxycarbonylphenyl ( 118) 3 , 4-dibutoxyphenyl (119) 3,4-diphenylphenyl (120) 3,4-diphenylthiophenyl (121) 3,4-dichlorophenyl (122) 3,4-dibenzoylphenyl (123) 3,4- Diacetoxyphenyl (124) 3,4-dibenzoyloxyphenyl (125) 3,4-diphenoxycarbonylphenyl (126) 3,4-dimethoxyphenyl (127) 3,4-dianilinophenyl (128) 3,4 -Dimethylphenyl (129) 3,4-diphenoxyphenyl (130) 3,4-dihydroxyphenyl (131) 2-naphthyl (132) 3,4,5-triethoxycarbonylphenyl (133) 3,4,5- Tributoxyphenyl (134) 3,4,5-triphenylphenyl (135) 3 4,5-triphenylthiophenyl (136) 3,4,5-trichlorophenyl (137) 3,4,5-tribenzoylphenyl (138) 3,4,5-triacetoxyphenyl (139) 3,4 5-tribenzoyloxyphenyl (140) 3,4,5-triphenoxycarbonylphenyl (141) 3,4,5-trimethoxyphenyl (142) 3,4,5-trianilinophenyl (143) 3,4 , 5-trimethylphenyl (144) 3,4,5-triphenoxyphenyl (145) 3,4,5-trihydroxyphenyl

(146) phenyl (147) 4-ethoxycarbonylphenyl (148) 4-butoxyphenyl (149) p-biphenylyl (150) 4-phenylthiophenyl (151) 4-chlorophenyl (152) 4-benzoylphenyl (153) 4 -Acetoxyphenyl (154) 4-benzoyloxyphenyl (155) 4-phenoxycarbonylphenyl (156) 4-methoxyphenyl (157) 4-anilinophenyl (158) 4-isobutyrylaminophenyl (159) 4-phenoxy Carbonylaminophenyl (160) 4- (3-ethylureido) phenyl (161) 4- (3,3-diethylureido) phenyl (162) 4-methylphenyl (163) 4-phenoxyphenyl (164) 4-hydroxyphenyl

(165) phenyl (166) 4-ethoxycarbonylphenyl (167) 4-butoxyphenyl (168) p-biphenylyl (169) 4-phenylthiophenyl (170) 4-chlorophenyl (171) 4-benzoylphenyl (172) 4 -Acetoxyphenyl (173) 4-benzoyloxyphenyl (174) 4-phenoxycarbonylphenyl (175) 4-methoxyphenyl (176) 4-anilinophenyl (177) 4-isobutyrylaminophenyl (178) 4-phenoxy Carbonylaminophenyl (179) 4- (3-ethylureido) phenyl (180) 4- (3,3-diethylureido) phenyl (181) 4-methylphenyl (182) 4-phenoxyphenyl (183) 4-hydroxyphenyl

(184) phenyl (185) 4-ethoxycarbonylphenyl (186) 4-butoxyphenyl (187) p-biphenylyl (188) 4-phenylthiophenyl (189) 4-chlorophenyl (190) 4-benzoylphenyl (191) 4 -Acetoxyphenyl (192) 4-benzoyloxyphenyl (193) 4-phenoxycarbonylphenyl (194) 4-methoxyphenyl (195) 4-anilinophenyl (196) 4-isobutyrylaminophenyl (197) 4-phenoxy Carbonylaminophenyl (198) 4- (3-ethylureido) phenyl (199) 4- (3,3-diethylureido) phenyl (200) 4-methylphenyl (201) 4-phenoxyphenyl (202) 4-hydroxyphenyl

(203) phenyl (204) 4-ethoxycarbonylphenyl (205) 4-butoxyphenyl (206) p-biphenylyl (207) 4-phenylthiophenyl (208) 4-chlorophenyl (209) 4-benzoylphenyl (210) 4 -Acetoxyphenyl (211) 4-benzoyloxyphenyl (212) 4-phenoxycarbonylphenyl (213) 4-methoxyphenyl (214) 4-anilinophenyl (215) 4-isobutyrylaminophenyl (216) 4-phenoxy Carbonylaminophenyl (217) 4- (3-ethylureido) phenyl (218) 4- (3,3-diethylureido) phenyl (219) 4-methylphenyl (220) 4-phenoxyphenyl (221) 4-hydroxyphenyl

(222) phenyl (223) 4-butylphenyl (224) 4- (2-methoxy-2-ethoxyethyl) phenyl (225) 4- (5-nonenyl) phenyl (226) p-biphenylyl (227) 4-ethoxy Carbonylphenyl (228) 4-butoxyphenyl (229) 4-methylphenyl (230) 4-chlorophenyl (231) 4-phenylthiophenyl (232) 4-benzoylphenyl (233) 4-acetoxyphenyl (234) 4-benzoyl Oxyphenyl (235) 4-phenoxycarbonylphenyl (236) 4-methoxyphenyl (237) 4-anilinophenyl (238) 4-isobutyrylaminophenyl (239) 4-phenoxycarbonylaminophenyl (240) 4- ( 3-ethylureido Phenyl (241) 4- (3,3-diethylureido) phenyl (242) 4-phenoxyphenyl (243) 4-hydroxyphenyl (244) 3-butylphenyl (245) 3- (2-methoxy-2-ethoxyethyl) ) Phenyl (246) 3- (5-nonenyl) phenyl (247) m-biphenylyl (248) 3-ethoxycarbonylphenyl (249) 3-butoxyphenyl (250) 3-methylphenyl (251) 3-chlorophenyl (252) 3-phenylthiophenyl (253) 3-benzoylphenyl (254) 3-acetoxyphenyl (255) 3-benzoyloxyphenyl (256) 3-phenoxycarbonylphenyl (257) 3-methoxyphenyl (258) 3-anilinophenyl (259) 3-I Butyrylaminophenyl (260) 3-phenoxycarbonylaminophenyl (261) 3- (3-ethylureido) phenyl (262) 3- (3,3-diethylureido) phenyl (263) 3-phenoxyphenyl (264) 3 -Hydroxyphenyl (265) 2-butylphenyl (266) 2- (2-methoxy-2-ethoxyethyl) phenyl (267) 2- (5-nonenyl) phenyl (268) o-biphenylyl (269) 2-ethoxycarbonyl Phenyl (270) 2-Butoxyphenyl (271) 2-Methylphenyl (272) 2-Chlorophenyl (273) 2-Phenylthiophenyl (274) 2-Benzoylphenyl (275) 2-Acetoxyphenyl (276) 2-Benzoyloxy Phenyl (277) 2 Phenoxycarbonylphenyl (278) 2-methoxyphenyl (279) 2-anilinophenyl (280) 2-isobutyrylaminophenyl (281) 2-phenoxycarbonylaminophenyl (282) 2- (3-ethylureido) phenyl ( 283) 2- (3,3-diethylureido) phenyl (284) 2-phenoxyphenyl (285) 2-hydroxyphenyl (286) 3,4-dibutylphenyl (287) 3,4-di (2-methoxy-2) -Ethoxyethyl) phenyl (288) 3,4-diphenylphenyl (289) 3,4-diethoxycarbonylphenyl (290) 3,4-didodecyloxyphenyl (291) 3,4-dimethylphenyl (292) 3, 4-dichlorophenyl (293) 3,4-dibenzoyl Enyl (294) 3,4-diacetoxyphenyl (295) 3,4-dimethoxyphenyl (296) 3,4-di-N-methylaminophenyl (297) 3,4-diisobutyrylaminophenyl (298) 3 , 4-diphenoxyphenyl (299) 3,4-dihydroxyphenyl (300) 3,5-dibutylphenyl (301) 3,5-di (2-methoxy-2-ethoxyethyl) phenyl (302) 3,5- Diphenylphenyl (303) 3,5-diethoxycarbonylphenyl (304) 3,5-didodecyloxyphenyl (305) 3,5-dimethylphenyl (306) 3,5-dichlorophenyl (307) 3,5-dibenzoyl Phenyl (308) 3,5-diacetoxyphenyl (309) 3,5-dimethoxyphenyl (3 0) 3,5-di-N-methylaminophenyl (311) 3,5-diisobutyrylaminophenyl (312) 3,5-diphenoxyphenyl (313) 3,5-dihydroxyphenyl (314) 2,4 -Dibutylphenyl (315) 2,4-di (2-methoxy-2-ethoxyethyl) phenyl (316) 2,4-diphenylphenyl (317) 2,4-diethoxycarbonylphenyl (318) 2,4-di Dodecyloxyphenyl (319) 2,4-dimethylphenyl (320) 2,4-dichlorophenyl (321) 2,4-dibenzoylphenyl (322) 2,4-diacetoxyphenyl (323) 2,4-dimethoxyphenyl ( 324) 2,4-di-N-methylaminophenyl (325) 2,4-diisobutyrylaminopheny (326) 2,4-diphenoxyphenyl (327) 2,4-dihydroxyphenyl (328) 2,3-dibutylphenyl (329) 2,3-di (2-methoxy-2-ethoxyethyl) phenyl (330) 2,3-diphenylphenyl (331) 2,3-diethoxycarbonylphenyl (332) 2,3-didodecyloxyphenyl (333) 2,3-dimethylphenyl (334) 2,3-dichlorophenyl (335) 2, 3-dibenzoylphenyl (336) 2,3-diacetoxyphenyl (337) 2,3-dimethoxyphenyl (338) 2,3-di-N-methylaminophenyl (339) 2,3-diisobutyrylaminophenyl (340) 2,3-diphenoxyphenyl (341) 2,3-dihydroxyphenyl (342 2,6-dibutylphenyl (343) 2,6-di (2-methoxy-2-ethoxyethyl) phenyl (344) 2,6-diphenylphenyl (345) 2,6-diethoxycarbonylphenyl (346) 2, 6-didodecyloxyphenyl (347) 2,6-dimethylphenyl (348) 2,6-dichlorophenyl (349) 2,6-dibenzoylphenyl (350) 2,6-diacetoxyphenyl (351) 2,6- Dimethoxyphenyl (352) 2,6-di-N-methylaminophenyl (353) 2,6-diisobutyrylaminophenyl (354) 2,6-diphenoxyphenyl (355) 2,6-dihydroxyphenyl (356) 3,4,5-tributylphenyl (357) 3,4,5-tri (2-methoxy-2-ethoxy) Til) phenyl (358) 3,4,5-triphenylphenyl (359) 3,4,5-triethoxycarbonylphenyl (360) 3,4,5-tridodecyloxyphenyl (361) 3,4,5- Trimethylphenyl (362) 3,4,5-trichlorophenyl (363) 3,4,5-tribenzoylphenyl (364) 3,4,5-triacetoxyphenyl (365) 3,4,5-trimethoxyphenyl ( 366) 3,4,5-tri-N-methylaminophenyl (367) 3,4,5-triisobutyrylaminophenyl (368) 3,4,5-triphenoxyphenyl (369) 3,4,5 -Trihydroxyphenyl (370) 2,4,6-tributylphenyl (371) 2,4,6-tri (2-methoxy-2-ethoxyethyl) ) Phenyl (372) 2,4,6-triphenylphenyl (373) 2,4,6-triethoxycarbonylphenyl (374) 2,4,6-tridodecyloxyphenyl (375) 2,4,6-trimethyl Phenyl (376) 2,4,6-trichlorophenyl (377) 2,4,6-tribenzoylphenyl (378) 2,4,6-triacetoxyphenyl (379) 2,4,6-trimethoxyphenyl (380 ) 2,4,6-tri-N-methylaminophenyl (381) 2,4,6-triisobutyrylaminophenyl (382) 2,4,6-triphenoxyphenyl (383) 2,4,6- Trihydroxyphenyl (384) Pentafluorophenyl (385) Pentachlorophenyl (386) Pentamethoxyphenyl (38 ) 6-N-methylsulfamoyl-8-methoxy-2-naphthyl (388) 5-N-methylsulfamoyl-2-naphthyl (389) 6-N-phenylsulfamoyl-2-naphthyl (390) 5-Ethoxy-7-N-methylsulfamoyl-2-naphthyl (391) 3-methoxy-2-naphthyl (392) 1-ethoxy-2-naphthyl (393) 6-N-phenylsulfamoyl-8- Methoxy-2-naphthyl (394) 5-methoxy-7-N-phenylsulfamoyl-2-naphthyl (395) 1- (4-methylphenyl) -2-naphthyl (396) 6,8-di-N- Methylsulfamoyl-2-naphthyl (397) 6-N-2-acetoxyethylsulfamoyl-8-methoxy-2-naphthyl (398) 5-acetoxy-7- N-phenylsulfamoyl-2-naphthyl (399) 3-benzoyloxy-2-naphthyl (400) 5-acetylamino-1-naphthyl (401) 2-methoxy-1-naphthyl (402) 4-phenoxy-1 -Naphtyl (403) 5-N-methylsulfamoyl-1-naphthyl (404) 3-N-methylcarbamoyl-4-hydroxy-1-naphthyl (405) 5-methoxy-6-N-ethylsulfamoyl- 1-naphthyl (406) 7-tetradecyloxy-1-naphthyl (407) 4- (4-methylphenoxy) -1-naphthyl (408) 6-N-methylsulfamoyl-1-naphthyl (409) 3- N, N-dimethylcarbamoyl-4-methoxy-1-naphthyl (410) 5-methoxy-6-N-benzylsulfamoyl 1-naphthyl (411) 3,6-di-N-phenylsulfamoyl-1-naphthyl (412) methyl (413) ethyl (414) butyl (415) octyl (416) dodecyl (417) 2-butoxy-2 -Ethoxyethyl (418) benzyl (419) 4-methoxybenzyl

(424) Methyl (425) Phenyl (426) Butyl

(430) methyl (431) ethyl (432) butyl (433) octyl (434) dodecyl (435) 2-butoxy-2-ethoxyethyl (436) benzyl (437) 4-methoxybenzyl

  The addition amount of these compounds is preferably 0.1 to 5.0% by mass, more preferably 0.5 to 1.5% by mass with respect to amylose ester and cellulose ester.

(Antioxidant)
Antioxidants are also referred to as deterioration inhibitors. When a liquid crystal image display device or the like is placed in a high humidity and high temperature state, the polarizing plate protective film may be deteriorated. The antioxidant has a role of delaying or preventing the polarizing plate protective film from being decomposed by, for example, the residual solvent amount of halogen in the polarizing plate protective film or phosphoric acid of the phosphoric acid plasticizer. It is preferable to make it contain in a polarizing plate protective film.

  As such an antioxidant, a hindered phenol compound is preferably used. For example, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di- -T-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [3 -(3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino)- 1,3,5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octa Sil-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, N, N'-hexamethylenebis (3,5-di-t-butyl-4-hydroxy-hydrocinnamamide) 1,3,5-trimethyl-2,4,6-tris (3,5-di-t-butyl-4-hydroxybenzyl) benzene, tris- (3,5-di-t-butyl-4-hydroxy Benzyl) -isocyanurate and the like. In particular, 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3 -(3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] is preferred. Further, for example, hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris (2,4-di- A phosphorus processing stabilizer such as t-butylphenyl) phosphite may be used in combination.

  The amount of these compounds added is preferably 1 to 10,000 ppm, more preferably 10 to 1000 ppm in terms of mass ratio with respect to amylose ester and cellulose ester.

(Matting agent)
Fine particles such as a matting agent can be added to the amylose ester and cellulose ester according to the present invention in order to impart slipperiness. Examples of the fine particles include fine particles of an inorganic compound or fine particles of an organic compound.

The addition amount of the fine particles is preferably 0.01 to 1.0 g, more preferably 0.03 to 0.5 g, and further preferably 0.08 to 0.3 g per 1 m ^{2 of} the polarizing plate protective film. Thereby, it is preferable that a convex part of 0.1-1 micrometer is formed in the polarizing plate protective film surface, and slipperiness is provided to a film.

  As fine particles added to the polarizing plate protective film, examples of inorganic compounds include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, calcium carbonate, talc, clay, calcined kaolin, calcined calcium silicate, and hydration. Mention may be made of calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. Among them, those containing silicon are preferable because the turbidity is low and the haze of the film can be reduced, and silicon dioxide is particularly preferable.

  In many cases, fine particles such as silicon dioxide are surface-treated with an organic material, but such particles are preferable because they can reduce the haze of the film. Preferred organic substances for the surface treatment include halosilanes, alkoxysilanes, silazanes, siloxanes, and the like.

  The silicon dioxide fine particles can be obtained, for example, by burning vaporized silicon tetrachloride and hydrogen mixed at 1000 to 1200 ° C. in the air.

  The fine particles of silicon dioxide preferably have a primary average particle diameter of 20 nm or less and an apparent specific gravity of 70 g / L or more. The average diameter of the primary particles is more preferably 5 to 16 nm, and further preferably 5 to 12 nm. These fine particles form a secondary agglomerate in the film and form unevenness on the film surface to impart slipperiness. A smaller primary particle average diameter is preferred because haze is low. The apparent specific gravity is more preferably 90 to 200 g / L or more, and further preferably 100 to 200 g / L or more. Higher apparent specific gravity makes it possible to produce a high-concentration fine particle dispersion, and less haze and large aggregates are generated. In the present invention, the liter is represented by L.

  As preferable fine particles of silicon dioxide, for example, Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (above Nippon Aerosil Co., Ltd.) manufactured by Nippon Aerosil Co., Ltd. Commercially available products can be mentioned, and Aerosil 200V, R972, R972V, R974, R202, R812 can be preferably used. The fine particles of zirconium oxide are commercially available, for example, under the trade names Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.), and any of them can be used.

  Among these, Aerosil 200V, Aerosil R972V, and Aerosil TT600 are particularly preferable because they have a large effect of lowering the turbidity and lowering the friction coefficient of the polarizing plate protective film of the present invention.

  Examples of organic compound fine particles include silicone resins, fluorine resins, and acrylic resins. Of these, silicone resins are preferred, and those having a three-dimensional network structure are particularly preferred. For example, Tospearl 103, 105, 108, 120, 145, 3120 and 240 (manufactured by Toshiba Silicone Co., Ltd.) Can be mentioned.

  In the measurement of the primary average particle diameter of the fine particles, the particles are observed with a transmission electron microscope (magnification of 500,000 to 2,000,000 times), 100 particles are observed, and the average value is used as the primary average particle diameter. I can do it.

  The apparent specific gravity described above can be calculated by the following formula by measuring a weight of a predetermined amount of silicon dioxide fine particles in a graduated cylinder and measuring the weight.

Apparent specific gravity (g / L) = silicon dioxide mass (g) / silicon dioxide volume (L)
The inorganic fine particles added here can impart slipperiness to the film surface, but the addition of a large amount of inorganic fine particles is accompanied by an increase in aggregates and a significant increase in haze.

[Production of polarizing plate protective film]
Hereinafter, the preferable manufacturing method of the polarizing plate protective film of this invention is demonstrated.

1) Dissolving step A step of dissolving the amylose ester and cellulose ester and additives in an organic solvent mainly containing a good solvent for amylose ester and cellulose ester while stirring to form a dope, or amylose ester and cellulose In this step, the additive solution is mixed with the ester solution to form a dope.

  For dissolution of amylose ester and cellulose ester, various methods such as a method performed at normal pressure, a method performed below the boiling point of the main solvent, a method performed under pressure above the boiling point of the main solvent, a method performed using a cooling dissolution method, a method performed at high pressure, etc. However, a method of pressurizing at a temperature equal to or higher than the boiling point of the main solvent is preferable.

  The concentration of amylose ester and cellulose ester in the dope is preferably 10 to 35% by mass. An additive is added to the dope during or after dissolution to dissolve and disperse, then filtered through a filter medium, defoamed, and sent to the next step with a liquid feed pump.

  Moreover, you may add the whole quantity or one part of additives, such as a plasticizer and a ultraviolet absorber, to this dope. After all the materials are dissolved, they are filtered with a filter medium, defoamed, and sent to the next process with a liquid feed pump.

2) Casting process On a metal support such as an endless metal belt, such as a stainless steel belt or a rotating metal drum, the dope is fed to a pressure die through a liquid feed pump (for example, a pressurized metering gear pump). The dope is cast from the pressure die slit at the casting position.

  A pressure die that can adjust the slit shape of the die base portion and can easily make the film thickness uniform is preferable. The pressure die includes a coat hanger die and a T die, and any of them is preferably used. The surface of the metal support is a mirror surface. In order to increase the film forming speed, two or more pressure dies may be provided on the metal support, and the dope amount may be divided and stacked. Or it is also preferable to obtain the film of a laminated structure by the co-casting method which casts several dope simultaneously.

3) Solvent evaporation step In this step, the web is heated on the metal support, and the solvent is evaporated until the web becomes peelable from the metal support.

  In order to evaporate the solvent, there are a method of blowing air from the web side and / or a method of transferring heat from the back side of the metal support by a liquid, a method of transferring heat from the front and back by radiant heat, and the like. However, the drying efficiency is preferable. A method of combining them is also preferable. In the case of backside liquid heat transfer, it is preferable to heat at or below the boiling point of the main solvent of the organic solvent used in the dope or the organic solvent having the lowest boiling point.

4) Peeling process It is the process of peeling the web which the solvent evaporated on the metal support body in a peeling position. The peeled web is sent to the next process. In addition, if the residual solvent amount (the following formula) of the web at the time of peeling is too large, peeling is difficult, or conversely, if the film is peeled off after being sufficiently dried on the metal support, a part of the web is in the middle. It may come off.

  Here, there is a gel casting method (gel casting) as a method of increasing the film forming speed (the film forming speed can be increased by peeling while the residual solvent amount is as large as possible). For example, there are a method in which a poor solvent for amylose ester and cellulose ester is added to the dope and the dope is cast and then gelled, a method in which the temperature of the metal support is lowered and gelled. By gelling on the metal support and increasing the strength of the film at the time of peeling, the speed of film formation can be increased by speeding up the peeling.

  The amount of residual solvent during peeling of the web on the metal support is preferably within a range of 5 to 150% by mass depending on the strength of drying conditions, the length of the metal support, etc., but the amount of residual solvent is larger. In the case of peeling at a point in time, if the web is too soft, flatness at the time of peeling is impaired, or slippage or vertical stripes due to peeling tension are likely to occur. Therefore, the residual solvent amount at the time of peeling is determined in consideration of economic speed and quality. In the present invention, the temperature at the peeling position on the metal support is preferably -50 to 40 ° C, more preferably 10 to 40 ° C, and most preferably 15 to 30 ° C.

  The residual solvent amount of the web at the peeling position is preferably 10 to 150% by mass, and more preferably 10 to 120% by mass.

  The amount of residual solvent can be represented by the following formula.

Residual solvent amount (% by mass) = {(MN) / N} × 100
Here, M is the mass of the web at an arbitrary point in time, and N is the mass when the mass M is dried at 110 ° C. for 3 hours.

5) Drying and stretching step and dyeing step After peeling, use a drying device that conveys the web alternately through a plurality of rolls arranged in the drying device, and / or a tenter device that clips and conveys both ends of the web with clips. And dry the web.

  As a drying means, hot air is generally blown on both sides of the web, but there is also a means for heating by applying a microwave instead of the wind. Too rapid drying tends to impair the flatness of the finished film. Throughout, the drying temperature is usually in the range of 40 to 250 ° C. The drying temperature, the amount of drying air, and the drying time differ depending on the solvent used, and the drying conditions may be appropriately selected according to the type and combination of the solvents used.

  The stretching process in producing the polarizing plate protective film of the present invention includes uniaxial stretching, biaxial stretching, etc., and either may be used, and the stretching method may be either dry stretching in air or wet stretching in a water bath. Good. The draw ratio is preferably 1 to 2 times, more preferably 1 to 1.5 times.

  The iodine dyeing process in producing the polarizing plate protective film of the present invention may be a general method, and potassium iodide may be used as a dissolution aid. Thereby, iodine can be adsorbed in the film by utilizing the inclusion effect of amylose. The concentration of the iodine solution is preferably 0.01 to 1% by mass, the ratio of iodine and potassium iodide can be arbitrarily changed, and the temperature of the iodine solution is preferably 20 to 40 ° C., and the immersion time Is preferably 3 to 300 seconds, but the temperature and immersion time of the iodine solution can be arbitrarily changed. The iodine dyeing process may be performed before or after the stretching process.

  Although the thickness of a film is not specifically limited, For example, the film of arbitrary thickness, such as a thing of about 10 micrometers-1 mm, can be produced. Preferably, the film thickness after drying, stretching and the like is preferably 10 to 500 μm, particularly preferably 30 to 120 μm.

[Polarizing plate and liquid crystal display]
(Polarizer)
The polarizing plate of the present invention will be described.

  The polarizing plate of the present invention can be produced by a general method. For example, there is a method in which a polarizing plate protective film of the present invention is subjected to alkali saponification treatment and then bonded to both sides of a polarizer produced by immersing and stretching in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. The alkali saponification treatment refers to a treatment of immersing the polarizing plate protective film of the present invention in a high-temperature strong alkaline solution in order to improve the wetness of the water-based adhesive and improve the adhesion.

  A conventionally well-known thing can be used as a polarizer used for the polarizing plate of this invention. For example, polyvinyl alcohol or a polyvinyl alcohol film such as ethylene-modified polyvinyl alcohol having an ethylene unit content of 1 to 4 mol%, a degree of polymerization of 2000 to 4000, and a degree of saponification of 99.0 to 99.99 mol% Some are dyed with chromatic dyes. The polarizer is preferably dyed by uniaxially stretching a polyvinyl alcohol film, or uniaxially stretched after dyeing, and then preferably subjected to a durability treatment with a boron compound. Further, a plastic film such as vinyl chloride that has been processed and oriented can also be used.

  The polarizer thus obtained is bonded to the polarizing plate protective film of the present invention. At this time, the polarizing plate protective film of the present invention is used for at least one sheet. Another polarizing plate protective film can be used on the other surface, and the polarizing plate protective film of the present invention may also be used on the other surface. In addition, commercially available cellulose ester films (KC8UX2M, KC4UX2M, KC5UN, KC4UY, KC8UY, KC8UCR-3, KC8UCR-4, KC8UCR-5, KC4FR-1, KC8UY-HA, KC8UX-RHA (manufactured by Konica Minolta Co., Ltd.) ) Can be used as a polarizing plate protective film on the other side.

  In addition to the antiglare layer or the clear hard coat layer, the polarizing plate protective film used on the surface side of the display device preferably has an antireflection layer, an antistatic layer, and an antifouling layer.

(Liquid crystal display device)
The polarizing plate of the present invention obtained as described above can be placed on both surfaces of a liquid crystal cell and bonded to produce a liquid crystal display device.

  In this case, it is particularly preferable for production to use a long film to bond by roll-to-roll. The liquid crystal display device that can be used is preferably a liquid crystal display device that employs various driving methods such as TN, VA, OCB, and HAN.

  EXAMPLES Hereinafter, although an Example demonstrates this invention, this invention is not limited to these.

Example 1
<< Production of Polarizing Plate Protective Film 101 >>
<Fine particle dispersion>
Silicon dioxide fine particles (Aerosil R972V manufactured by Nippon Aerosil Co., Ltd.) 11 parts by weight Ethanol 89 parts by weight The above was stirred and mixed with a dissolver for 50 minutes, and then dispersed with Manton Gorin to prepare a fine particle dispersion.

<Fine particle additive solution>
Cellulose ester was added to a dissolution tank containing methylene chloride, and heated to completely dissolve, and this was then added to Azumi Filter Paper No. Filtered using 244. The fine particle dispersion was slowly added thereto while sufficiently stirring the filtered cellulose ester solution. Furthermore, dispersion was carried out with an attritor. This was filtered through Finemet NF manufactured by Nippon Seisen Co., Ltd. to prepare a fine particle additive solution.

Methylene chloride 99 parts by weight Cellulose ester 4 parts by weight Fine particle dispersion 11 parts by weight A main dope solution having the following composition was prepared. First, methylene chloride and ethanol were added to the pressure dissolution tank. Amylose ester and cellulose ester were added to a pressure dissolution tank containing a solvent while stirring. This was heated and stirred to dissolve completely, and a plasticizer and an ultraviolet absorber were further added and dissolved. This was designated as Azumi Filter Paper No. The main dope solution was prepared by filtration using 244.

  In addition to adding 100 parts by mass of the main dope solution and 2 parts by mass of the fine particle additive solution, mix thoroughly with an in-line mixer (Toray static type in-pipe mixer Hi-Mixer, SWJ), and then use a belt casting apparatus to adjust the width. It was cast uniformly on a 2 m stainless steel band support. On the stainless steel band support, the solvent was evaporated until the residual solvent amount became 110%, and the stainless steel band support was peeled off. Furthermore, it was conveyed for 30 minutes in the drying zone set to 125 degreeC, and it dried. Thereafter, the film is stretched 1.2 times in the transport direction, then immersed in 100 parts by mass of an aqueous solution containing 1 part by mass of iodine at room temperature, and a film having a knurling of 1.5 m in width, 1 cm in width at the end, and 8 μm in height. A polarizing plate protective film 101 having a thickness of 80 μm was produced.

<Composition of main dope solution>
Methylene chloride 300 parts by weight Ethanol 52 parts by weight Cellulose ester (see Table 1) 70 parts by weight Amylose ester (see Table 1) 30 parts by weight Plasticizer A (trimethylolpropane tribenzoate) 5 parts by weight Plasticizer B (Sample No. 3) (Aromatic terminal ester)) 5 parts by mass UV absorber (Tinubin 109 (Ciba Specialty Chemicals))
1.3 parts by weight UV absorber (Tinubin 171 (Ciba Specialty Chemicals Co., Ltd.))
0.6 part by mass << Preparation of polarizing plate protective films 102-110 >>
In the production of the polarizing plate protective film 101, polarizing plate protective films 102 to 110 were produced in the same manner except that the mixing ratio of cellulose ester and amylose ester shown in Table 1 below and the presence or absence of staining with an iodine solution were changed. .

<Production of polarizing plate>
Using the raw film samples of the above-prepared polarizing plate protective films 101 to 110, the alkali saponification treatment and polarizing plate described below were prepared.

<Alkali saponification treatment>
Saponification process 2M-NaOH 50 ° C. 90 seconds Water washing process Water 30 ° C. 45 seconds Neutralization process 10% HCl 30 ° C. 45 seconds Water washing process Water 30 ° C. 45 seconds After saponification treatment, water washing, neutralization, water washing are performed in this order. Subsequently, it dried at 80 degreeC.

<Production of polarizer>
A 120 μm-thick long roll polyvinyl alcohol film was immersed in 100 parts by mass of an aqueous solution containing 1 part by mass of iodine and 4 parts by mass of boric acid, and stretched in the transport direction 5 times at 50 ° C. to produce a polarizer.

  The polarizing plate protective films 101 to 110 were bonded to both surfaces of the polarizing film using a completely saponified polyvinyl alcohol 5% aqueous solution as an adhesive and dried to prepare polarizing plates P101 to P110.

<< Evaluation of polarizing plate >>
The following evaluation was performed about the obtained polarizing plate.

<Degree of polarization>
The polarization degree of the polarizing plate of the present invention is obtained by superposing the transmission axes of the same two polarizing plates of the present invention in parallel using a spectrophotometer (Hitachi Ltd., U3310) in an environment of 23 ° C. and 55%. The transmittance (T2) in the case of being superimposed perpendicularly to the transmittance (T1) at the time of measurement was measured, and the degree of polarization was determined from the following formula.
Degree of polarization (%) = √ (T1−T2) / (T1 + T2) × 100
Further, the polarization degree when the polarizing plate was left in an environment of 80 ° C. and 90% RH for 48 hours was also obtained in the same manner. Table 1 shows the result of evaluation when the wavelength is 500 nm.

  From the table, it is clear that the polarizing plate of the present invention has little deterioration in polarization characteristics even in a high temperature and high humidity environment.

Claims (3)

A polarizing plate protective film comprising amylose ester and cellulose ester and dyed with an iodine solution. The polarizing plate protective film according to claim 1, wherein the total acyl group substitution degree of the amylose ester is in the range of 0.1 to 2.5. A polarizing plate comprising the polarizing plate protective film according to claim 1 on at least one surface of a polarizer.