JP2009173819A - Functional film, polarizing plate, and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a functional film of cellulose ester excellent in optical properties and surface properties by resolving conventional troubles of a cellulose ester film produced via a film formation method using a melting state, as well as to provide a polarizing plate using it and a liquid crystal display device. <P>SOLUTION: This functional film has a hard coat layer on a surface of the cellulose ester film produced via a film formation method using a melting state, wherein the cellulose ester film contains 0.05-2.0 mass% of at least one from among glycerol fatty acid ester, diglycerol fatty acid ester and sorbitan fatty acid ester, and the hard coat layer contains an organic solvent of 20-45 mass% having a solubility parameter of 18.5-21 (MPa)<SP>1/2</SP>in its coating solution. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a functional film of cellulose ester produced by a melt film-forming method and excellent in optical performance and surface characteristics, a polarizing plate using the same, and a liquid crystal display device.

  Since the cellulose ester film is excellent in transparency and optical isotropy, it is applied to various optical films. In addition, since the film surface can be hydrophilized by alkali saponification treatment, it has good adhesion to a polarizer and is particularly suitable for a polarizing plate protective film.

  On the other hand, the cellulose ester film has generally been formed by a solution film forming method, but in recent years, the film forming examination by the melt film forming method has been advanced. Usually, cellulose ester called cellulose triacetate (TAC) is used in the solution casting method. In the melt casting method, cellulose acetate propionate (CAP) is used to form a melt by lowering the melting temperature. And cellulose acetate butyrate (CAB) have been proposed.

  However, when these films are used as a base film such as a hard coat film or an antireflection film, the solubility in organic solvents is too good, so that coating using a solvent such as commonly used acetone or methyl ethyl ketone is performed. When the liquid is applied, the surface of the base film is eroded, resulting in a problem that the surface characteristics are remarkably deteriorated, and it is difficult to impart functionality. As the surface characteristics of the base film that deteriorates, haze, pencil hardness, and the like can be raised, but it has been found that the deterioration of the pencil hardness is particularly remarkable.

Patent Document 1 proposes a method for setting the solubility parameter of the organic solvent of the functional layer coating solution to 18.5 (MPa) ^1/2 or less or 21 (MPa) ^1/2 or more. Although this method improves the haze, it has been found that the pencil hardness is not sufficiently improved, and the adhesion between the functional layer and the substrate film deteriorates.

Patent Documents 2 to 4 describe examples in which glycerin fatty acid ester or diglycerin fatty acid ester is added. In this method, the contact angle can be reduced, but since both are added as a plasticizer, the addition amount is 2% or more, the elastic modulus is too low, and the dimensional change of the polarizing plate becomes large. It was also found that the polarizing plate failed because the amount of elution into the saponification process increased.
JP 2007-217606 A JP 2004-131670 A JP 2007-51304 A JP 2007-144883 A

  The present invention has been made in view of the above-described problems and situations, and the solution is to solve the conventional problems of cellulose ester films produced by a melt film-forming method, which have excellent optical performance and surface characteristics. It is providing the functional film of the cellulose ester excellent in the.

  Furthermore, it is providing the polarizing plate and liquid crystal display device using the same.

  The above-mentioned problem according to the present invention is solved by the following means.

1. A functional film having a hard coat layer on the surface of a cellulose ester film produced by a melt film-forming method, wherein the cellulose ester film comprises at least one of glycerin fatty acid ester, diglycerin fatty acid ester, and sorbitan fatty acid ester 20 to 45% by mass of an organic solvent containing 0.05 to 2.0% by mass and having a solubility parameter of 18.5 to 21 (MPa) ^1/2 in the coating liquid of the hard coat layer. A functional film containing the functional film.

  2. 2. The functional film as described in 1 above, wherein the film is stretched within a range where the sum of the stretching ratio in the fluent direction and the stretching ratio in the direction perpendicular to the fluent direction is 20 to 300%.

  3. 3. The functional film as described in 1 or 2 above, wherein 2 to 20% by mass of at least one kind of aromatic carboxylic acid ester of pentaerythritol is contained.

  4). The functional film as described in any one of said 1-3 is used, The polarizing plate characterized by the above-mentioned.

  5). 5. A liquid crystal display device using the polarizing plate described in 4 above.

  By the above-mentioned means of the present invention, the conventional problems of the cellulose ester film produced by the melt film-forming method can be solved, and a functional film of cellulose ester having excellent optical performance and excellent surface characteristics can be provided. . Furthermore, a polarizing plate and a liquid crystal display device using the same can be provided.

The functional film of the present invention is a functional film having a hard coat layer on the surface of a cellulose ester film produced by a melt film-forming method, and the cellulose ester film is a glycerin fatty acid ester, a diglycerin fatty acid ester, And at least one of sorbitan fatty acid esters in an amount of 0.05 to 2.0% by mass, and the hard coat layer has a solubility parameter of 18.5 to 21 (MPa) ^{1 / The} organic solvent which is ² is contained 20 to 45 mass%. This feature is a technical feature common to the inventions according to claims 1 to 5.

  As an embodiment of the present invention, the sum of the draw ratio in the fluent direction (hereinafter referred to as “MD direction” as appropriate) and the draw ratio in the direction perpendicular to the fluent direction (hereinafter referred to as “TD direction” as appropriate). It is preferable that the film is stretched within a range of 20 to 300%. Moreover, it is preferable that the said cellulose-ester film contains 2-20 mass% of at least 1 type in the aromatic carboxylic acid ester of pentaerythritol.

  Especially the cellulose-ester film of this invention can be used suitably for the polarizing plate used for a liquid crystal display device.

  Hereinafter, the present invention, its components, and the best mode and mode for carrying out the invention will be described in detail.

<Fatty acid esters such as glycerin fatty acid ester>
Examples of fatty acids constituting the glycerin fatty acid ester, diglycerin fatty acid ester, and sorbitan fatty acid ester used in the present invention include lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, 12-hydroxystearic acid, oleic acid, and linoleic acid. The main component is one or a mixture of two or more selected from aliphatic fatty acids having 12 to 22 carbon atoms, such as acid, erucic acid, and 12-hydroxyoleic acid.

  In the present invention, the glycerin fatty acid ester and diglycerin fatty acid ester are preferably composed mainly of monoesters and diesters.

  As a sorbitan fatty acid ester, it is preferable to have a monoester, a diester, and a triester as a main component. Moreover, the hydroxyl group which is not esterified with the aliphatic fatty acid having 12 to 22 carbon atoms may be a hydroxyl group or may be esterified with acetic acid.

  In addition, it is preferable that the carbon number is 12 to 22 from the viewpoints of contamination of the manufacturing / processing apparatus due to volatility during heating, environmental pollution prevention, compatibility with cellulose ester, and the like. In addition, from the viewpoints of deodorization during storage, prevention of discoloration, and the like, esters of saturated fatty acids are preferred over unsaturated fatty acids.

  The addition amount of glycerin fatty acid ester, diglycerin fatty acid ester, and sorbitan fatty acid ester is 0.05% by mass to 2.0% by mass, and more preferably 0.1% by mass to 1.5% by mass. If the addition amount is too small, the necessary effect cannot be obtained, and if the addition amount is too large, bleeding out occurs, and the change in the dimensions of the polarizing plate and the failure of the polarizing plate deteriorate.

  Esterification reaction of glycerin, diglycerin, sorbitol and the above fatty acids is beef tallow, lard, chicken tallow, fish oil, soybean oil, corn oil, rapeseed oil, palm oil, sunflower oil, safflower oil, castor oil or their Methods such as molecular distillation, solvent fractionation, recrystallization, column chromatography, and supercritical gas extraction of reactants obtained by transesterification of one or a mixture of hydrogenated oils with glycerin, diglycerin, and sorbitol In general, molecular distillation is suitable from the viewpoint of ease of production, quality, and price.

  By using any one of glycerin fatty acid ester, diglycerin fatty acid ester, and sorbitan fatty acid ester, coloring (yellowing) and minute surface defects of the melt film-forming film of the present invention can be improved. This is because glycerin fatty acid ester, diglycerin fatty acid ester, sorbitan fatty acid ester act like a lubricant, improve the retention in the extruder, fluted die, etc., and reduce the friction between metal and molten resin, This is thought to be due to the prevention of heat generation and stress due to frictional heat.

  Moreover, it was found that the contact angle to water can be improved by our examination. The reason for this is not known, but it is thought that the surface state of the melt-formed film is changed by acting like a surfactant.

<Cellulose ester>
Although there is no limitation in particular in the cellulose ester used for this invention, It is preferable that it is a C2-C22 carboxylic acid ester of a cellulose, The ester of aromatic carboxylic acid may be sufficient, and especially C2-C6 of a cellulose. More preferably, it is a lower fatty acid ester.

  The acyl group bonded to the hydroxyl group may be linear or branched, and may form a ring. Further, another substituent may be substituted.

  Examples of preferred cellulose esters include cellulose acetate, cellulose propionate, cellulose butyrate, and the like, JP-A-10-45804, 08-231761, U.S. Pat. No. 2,319,052, and the like. Examples thereof include mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate.

  Preferred cellulose esters for the present invention are those that simultaneously satisfy the following formulas (1) and (2).

Formula (1): 2.0 ≦ X + Y ≦ 3.0
Formula (2): 0 ≦ Y ≦ 1.5
In the formula, X is the degree of substitution of the acetyl group, and Y is the degree of substitution of the propionyl group or butyryl group. The portion that is not substituted with an acyl group usually exists as a hydroxyl group. The measuring method of the substitution degree of an acyl group can be measured according to ASTM-D817-96.

  The number average molecular weight of the cellulose ester used in the present invention is preferably in the range of 60,000 to 300,000, more preferably 70,000 to 200,000, from the viewpoints of melt viscosity and mechanical strength.

  The cellulose ester used in the present invention preferably has a weight average molecular weight (Mw) / number average molecular weight (Mn) value of 1.4 to 3.0, more preferably 1.4 to 2.2. It is. By setting Mw / Mn within this range, white turbidity is less likely to occur when the cellulose ester film is stretched, and the elastic modulus is likely to increase. It is considered that the smaller the Mw / Mn value, the smaller the molecular weight distribution, so that the polymer molecules are easily oriented and a uniform film with few voids is likely to be formed.

  The average molecular weight and molecular weight distribution of the cellulose ester can be measured by a known method using high performance liquid chromatography. Using these, the number average molecular weight and the weight average molecular weight can be calculated, and the ratio (Mw / Mn) can be calculated.

  The measurement conditions of the number average molecular weight and the weight average molecular weight using high performance liquid chromatography are as follows.

Solvent: Methylene chloride Column: Shodex K806, K805, K803G (Used by connecting three Showa Denko Co., Ltd.)
Column temperature: 25 ° C
Sample concentration: 0.1% by mass
Detector: RI Model 504 (manufactured by GL Sciences)
Pump: L6000 (manufactured by Hitachi, Ltd.)
Flow rate: 1.0ml / min
Calibration curve: Standard polystyrene STK standard polystyrene (manufactured by Tosoh Corp.) Mw = 100000-500 calibration curves with 13 samples were used. It is preferable to obtain 13 samples at approximately equal intervals.

  The cellulose used as a raw material for the cellulose ester used in the present invention is not particularly limited, and examples thereof include cotton linter, wood pulp, and kenaf. Moreover, the cellulose ester obtained from them can be mixed and used in arbitrary ratios, respectively.

  In the cellulose ester according to the present invention, when the acylating agent of the cellulose raw material is an acid anhydride (acetic anhydride, propionic anhydride, butyric anhydride), an organic solvent such as acetic acid or an organic solvent such as methylene chloride is used. The reaction is carried out using a protic catalyst such as sulfuric acid.

  When the acylating agent is acid chloride, the reaction is carried out using a basic compound such as an amine as a catalyst. Specifically, it can be synthesized with reference to the method described in JP-A-10-45804.

  Unlike the 2nd and 3rd positions, the glucose unit constituting the cellulose ester has a highly reactive primary hydroxyl group, and this primary hydroxyl group is sulfated during the production of cellulose ester using sulfuric acid as a catalyst. Esters are preferentially formed.

  Therefore, by increasing the amount of catalytic sulfuric acid in the esterification reaction of cellulose, it is possible to increase the average substitution degree at the 2nd and 3rd positions rather than the 6th position of the glucose unit as compared with a normal cellulose ester.

  Furthermore, if the cellulose is tritylated as necessary, the hydroxyl group at the 6-position of the glucose unit can be selectively protected. Therefore, the trityl group protects the hydroxyl group at the 6-position, and after esterification, the trityl group (protection) The average substitution degree at the 2nd and 3rd positions can be increased from the 6th position of the glucose unit. Specifically, a cellulose ester produced by the method described in JP-A No. 2005-281645 can also be preferably used.

  In addition, it is preferable to purify the synthesized cellulose ester to remove low molecular weight components, or to remove unacetylated or low acetylated components by filtration.

  In the case of mixed acid cellulose ester, it can be obtained by the method described in JP-A-10-45804.

  Cellulose esters are also affected by trace metal components in cellulose esters. These are considered to be related to water used in the production process, but it is preferable that there are few components that can become insoluble nuclei, and metal ions such as iron, calcium, and magnesium contain organic acidic groups. Insoluble matter may be formed by salt formation with a polymer degradation product or the like that may be present, and it is preferable that the amount is small.

  The alkaline earth metal content of the cellulose ester used in the present invention is preferably in the range of 1 to 50 ppm. If the alkaline earth metal content is in the above range, lip deposits are reduced, and no breakage occurs at the slitting part during or after hot stretching. Furthermore, the range of 1-30 ppm is preferable. The alkaline earth metal as used herein refers to the total content of Ca and Mg, and can be measured using an X-ray photoelectron spectrometer (XPS).

  The residual sulfuric acid content in the cellulose ester used in the present invention is preferably in the range of 0.1 to 45 ppm in terms of elemental sulfur. These are considered to be contained in the form of salts. When the residual sulfuric acid content is in the above range, the deposit on the die lip portion during heat melting is reduced, and breakage does not occur during slitting during heat stretching or after heat stretching. Furthermore, the range of 1-30 ppm is preferable. The residual sulfuric acid content can be measured by a method prescribed in ASTM-D817-96.

  The free acid content in the cellulose ester used in the present invention is preferably 1 to 500 ppm. When the free acid content is within the above range, the deposits on the die lip are reduced, and no breakage occurs during hot stretching or slitting after hot stretching. Furthermore, it is preferable that it is the range of 1-100 ppm, and also it becomes difficult to fracture | rupture. A range of 1 to 70 ppm is particularly preferable. The free acid content can be measured by a method prescribed in ASTM-D817-96.

<Aromatic carboxylic acid ester of pentaerythritol>
The aromatic carboxylic acid ester of pentaerythritol used in the present invention is obtained by esterifying some or all of the hydrogen atoms of the four hydroxyl groups of pentaerythritol with an aromatic carboxylic acid.

  Examples of preferred aromatic carboxylic acids include those in which an alkyl group is introduced into the benzene ring of benzoic acid such as benzoic acid and toluic acid, those in which a polar group such as a methoxy group or a hydroxyl group is introduced into the benzene ring of benzoic acid, Examples thereof include aromatic carboxylic acids having two or more benzene rings such as biphenyl carboxylic acid, naphthalene carboxylic acid, tetralin carboxylic acid, and derivatives thereof. In particular, benzoic acid is preferred.

  Moreover, it is preferable that at least two of the four hydroxyl groups of pentaerythritol are esterified with an aromatic carboxylic acid. Hydroxyl groups that are not esterified with an aromatic carboxylic acid may be esterified with other types of carboxylic acids, or may remain hydroxyl groups without esterification.

  There is no restriction | limiting in particular as carboxylic acid other than aromatic carboxylic acid used for esterification of pentaerythritol, A well-known aliphatic carboxylic acid, alicyclic carboxylic acid, etc. can be used. Use of an alicyclic carboxylic acid is preferable in terms of improving moisture permeability and retention. Examples of preferred carboxylic acids include the following, but the present invention is not limited thereto.

  As the aliphatic carboxylic 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 carboxylic acid.

  Preferred aliphatic carboxylic 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, and 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 preferred alicyclic carboxylic acids include cyclopentane carboxylic acid, cyclohexane carboxylic acid, cyclooctane carboxylic acid, or derivatives thereof.

  Moreover, the aromatic ring of aromatic carboxylic acid and the cycloalkyl group of alicyclic carboxylic acid may be substituted. Preferred substituents include halogen atoms such as chlorine atom, bromine atom and fluorine atom, hydroxyl group, alkyl group, alkoxy group, cycloalkoxy group, aralkyl group, alkenyl group such as vinyl group and allyl group, phenyl group, Examples thereof include an acyl group having 2 to 8 carbon atoms such as a phenoxy group, an acetyl group and a propionyl group, and an unsubstituted carbonyloxy group having 2 to 8 carbon atoms such as an acetyloxy group and a propionyloxy group.

  Examples of the alkoxy group include an alkoxy group having 1 to 8 carbon atoms, specifically, methoxy, ethoxy, n-propoxy, n-butoxy, n-octyloxy, isopropoxy, isobutoxy, 2-ethylhexyloxy, or and each alkoxy group such as t-butoxy.

  Examples of the cycloalkoxy group include cycloalkoxy groups having 1 to 8 carbon atoms, and specific examples include groups such as cyclopropyloxy, cyclopentyloxy, and cyclohexyloxy.

  Examples of the aralkyl group include groups such as a benzyl group, a phenethyl group, and a γ-phenylpropyl group.

  Examples of the aryloxy group include a phenoxy group.

  Examples of the aralkyloxy group include a benzyloxy group and a phenethyloxy group.

As an acyl group, C2-C8 acyl groups, such as an acetyl group and a propionyl group, are mentioned. (Acyl hydrocarbon groups include alkyl, alkenyl and alkynyl groups)
Examples of the carbonyloxy group include acyloxy groups having 2 to 8 carbon atoms such as acetyloxy group and propionyloxy group (the hydrocarbon group of the acyl group includes alkyl, alkenyl and alkynyl groups), and benzoyloxy groups. An arylcarbonyloxy group is mentioned.

  The oxycarbonyl group 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.

  The oxycarbonyloxy group represents an alkoxycarbonyloxy group having 1 to 8 carbon atoms such as a methoxycarbonyloxy group.

  The aromatic carboxylic acid ester of pentaerythritol used in the present invention can be easily obtained by an esterification reaction of pentaerythritol and carboxylic acid or acid chloride. In some cases, it can also be produced by transesterifying a previously prepared pentaerythritol ester with a carboxylic acid compound. The pentaerythritol ester compound of the present invention preferably has a 1% weight loss temperature (Td1) of 250 ° C. or higher, more preferably 280 ° C. or higher, and particularly preferably 300 ° C. or higher.

  The addition amount of the aromatic carboxylic acid ester of pentaerythritol used in the present invention is preferably 2% by mass to 20% by mass from the viewpoint of the effect of the present invention, bleed out, etc., and 4% by mass to 15% by mass. % Is more preferable.

  Pentaerythritol aromatic carboxylic acid ester has good compatibility with cellulose ester, so it has excellent properties as a plasticizer in the solution casting method. However, the melt casting method further reduces melt viscosity and causes volatilization. It is also preferable in terms of suppressing process contamination.

  Moreover, when it is set as a polarizing plate protective film, the effect which suppresses polarizer deterioration on high temperature, high humidity conditions is also excellent.

<Additives>
The present invention is characterized in that a melt containing a cellulose ester is formed into a film, and the melt contains an additive other than the cellulose ester. About the addition amount of an additive, it is preferable that all the additives are totaled and it is 2-50 mass% of the whole cellulose-ester film.

  Preferred additives are described below.

《Plasticizer》
In the production of the cellulose ester film according to the present invention, 2 to 30% by mass of at least one plasticizer is contained in the film forming material.

  Generally, a plasticizer is an additive having an effect of improving brittleness or imparting flexibility by being added to a polymer, but in the present invention, a cellulose ester alone is used. In order to lower the melting temperature than the melting temperature, and to lower the melt viscosity of the film constituting material containing the plasticizer than the cellulose ester alone at the same heating temperature, a plasticizer is added. Moreover, since it adds also in order to improve the hydrophilic property of a cellulose ester and to improve the equilibrium moisture content of a cellulose ester film, it has a function as a hydrophobizing agent.

  Here, the melting temperature of the film constituting material means a temperature at which the material is heated and fluidity is developed. In order to melt and flow the cellulose ester, it is necessary to heat at least a temperature higher than the glass transition temperature.

  Above the glass transition temperature, the elastic modulus or viscosity decreases due to heat absorption, and fluidity is exhibited. However, cellulose ester may melt at the same time as it melts at the same time, resulting in a decrease in the molecular weight of the cellulose ester, which may adversely affect the mechanical properties of the resulting film. Therefore, it is necessary to melt the cellulose ester at the lowest possible temperature. is there.

  In order to lower the melting temperature of the film constituent material, it can be achieved by adding a plasticizer having a melting point or glass transition temperature lower than the glass transition temperature of the cellulose ester.

  The above aromatic carboxylic acid ester of pentaerythritol also has a function as a plasticizer.

<Plasticizers other than pentaerythritol aromatic carboxylic acid ester>
A plasticizer other than the aromatic carboxylic acid ester of pentaerythritol may be added to the cellulose ester film of the present invention as necessary. The plasticizer that can be used is not particularly limited. For example, a polyhydric alcohol ester plasticizer, a polyester plasticizer, a trivalent or higher aromatic polycarboxylic acid ester plasticizer, a glycolate plasticizer, Phosphate ester plasticizers, phthalate ester plasticizers, fatty acid ester plasticizers, sugar ester compounds, acrylic polymers, and the like can be used. Particularly preferred are polyhydric alcohol plasticizers. Moreover, it is preferable that the addition amount of a phosphoric ester plasticizer shall be 6 mass% or less from a durable viewpoint of a polarization degree.

  The plasticizer preferably has a 1% weight loss temperature (Td1) of 250 ° C. or higher, more preferably 280 ° C. or higher, and particularly preferably 300 ° C. or higher.

  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 for the polyhydric alcohol ester is represented by the following general formula (1).

Formula (1): R1- (OH) _n
In the formula, R1 represents an n-valent organic group, n represents a positive integer of 2 or more, and the OH group represents an alcoholic hydroxyl group or a phenolic hydroxyl group.

  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, 1,2,3-hexanetriol, 1,2, 6-hexanetriol, glycerin, diglycerin, galactitol, inositol, mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, trimethylolethane, xylitol, etc. It can gel. Of these, glycerin, trimethylolethane, and trimethylolpropane are preferable.

  There is no restriction | limiting in particular as monocarboxylic acid used for the polyhydric alcohol ester of this invention, 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, and laccelic acid, undecylenic acid, Examples thereof include unsaturated fatty acids such as oleic acid, sorbic acid, linoleic acid, linolenic acid and arachidonic acid.

  Preferred alicyclic monocarboxylic acids are preferably cycloalkyl groups having 3 to 8 carbon atoms, and specific examples include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, and cyclooctanecarboxylic acid.

  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 biphenyl carboxylic acid, naphthalene carboxylic acid, and tetralin carboxylic acid. An aromatic monocarboxylic acid possessed can be mentioned. In particular, benzoic acid is preferred.

  These alicyclic monocarboxylic acids and aromatic monocarboxylic acids may be substituted, and preferred substituents include halogen atoms such as chlorine atom, bromine atom, fluorine atom, hydroxyl group, alkyl group, alkoxy group. Group, cycloalkoxy group, aralkyl group (this phenyl group may be further substituted with an alkyl group or a halogen atom), alkenyl groups such as vinyl group, allyl group, phenyl group (this phenyl group has an alkyl group) Or a phenoxy group (this phenyl group may be further substituted with an alkyl group or a halogen atom), an acetyl group, a propionyl group, or the like. ˜8 acyl groups, acetyloxy groups, propionyloxy groups, etc. Unsubstituted carbonyloxy group of 8 and the like.

  The molecular weight of the polyhydric alcohol ester is not particularly limited, but from the viewpoint of volatility, compatibility and the like, the molecular weight is preferably in the range of 300 to 1500, and more preferably in the range of 400 to 1000.

  One type of monocarboxylic acid used for polyhydric alcohol ester may be sufficient, and 2 or more types of mixtures may be sufficient as it. 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 polyhydric alcohol ester can be synthesized by a known method. For example, a method of condensing and esterifying the monocarboxylic acid and the polyhydric alcohol in the presence of an acid, a method of previously reacting an organic acid with an acid chloride or acid anhydride and reacting with the polyhydric alcohol, There is a method of reacting a phenyl ester and a polyhydric alcohol, and it is preferable to select a method with a good yield appropriately depending on the target ester compound.

  As the polyester plasticizer, it is preferable to use a polyester plasticizer having an aromatic ring or a cycloalkyl ring in the molecule. Although it does not specifically limit as a preferable polyester plasticizer, For example, it represents with the following general formula (i).

General formula (i): 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 2 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.)
In the general formula (i), a benzene monocarboxylic acid residue represented by B and an alkylene glycol residue, oxyalkylene glycol residue or aryl glycol residue represented by G, an alkylene dicarboxylic acid residue or aryl dicarboxylic group represented by A It is composed of an acid residue and can be obtained by a reaction similar to that of a normal polyester plasticizer.

  Examples of the benzene monocarboxylic acid component of the polyester plasticizer used in the present invention include benzoic acid, para-tert-butyl benzoic acid, orthotoluic acid, metatoluic acid, p-toluic acid, dimethyl benzoic acid, ethyl benzoic acid, and normal propyl. There are benzoic 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 polyester plasticizer include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,2-butanediol, 1,3-butanediol, 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-1,3propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentanediol 1,6 -Hexanediol, 2,2,4-trimethyl 1,3-pentanediol, 2-ethyl 1,3-hexanediol, 2- Chill 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, there are 1,12-octadecane diol, these glycols may be used as alone or in combination of two or more.

  In addition, examples of the oxyalkylene glycol component having 4 to 12 carbon atoms of the aromatic terminal ester of the present invention include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol. , One or a mixture of two or more.

  Examples of the alkylene dicarboxylic acid component having 4 to 12 carbon atoms of the aromatic terminal ester of the present invention include succinic acid, maleic acid, fumaric acid, glutaric acid, adipic acid, azelaic acid, sebacic acid, and dodecanedicarboxylic acid. These are each 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, isophthalic acid, terephthalic acid, 1,5 naphthalene dicarboxylic acid, and 1,4 naphthalene dicarboxylic acid.

  The polyester plasticizer used in the present invention has a number average molecular weight of preferably 400 to 2000, more preferably 500 to 1500. 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.

  The trivalent or higher aromatic polyvalent carboxylic acid ester plasticizer is preferably trimesic acid ester, trimellitic acid ester or pyromellitic acid ester. The alcohol that forms an ester with the aromatic polycarboxylic acid is preferably an alcohol having 1 to 8 carbon atoms.

  Examples of particularly preferred trivalent or higher aromatic polycarboxylic acid ester plasticizers include tributyl trimesate, trihexyl trimesate, tri-2-ethyl-hexyl trimesate, tricyclohexyl trimesate, tributyl trimellitic acid, trimellitate Trihexyl acid, Tri-2-ethyl-hexyl trimellitic acid, Tricyclohexyl trimellitic acid, Tetrabutyl pyromellitic acid, Tetrahexyl pyromellitic acid, Tetra-2-ethyl-hexyl pyromellitic acid, Tetracyclohexyl pyromellitic acid However, the present invention is not limited to these.

  As glycolate plasticizers, ethyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, and phosphate ester plasticizers are triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl. For phthalate ester plasticizers such as phosphate, trioctyl phosphate, tributyl phosphate, 1,3-phenylene bis (dixylenyl phosphate), 1,3-phenylene bis (diphenyl phosphate), diethyl phthalate, dimethoxyethyl phthalate, dimethyl Phthalate, dioctyl phthalate, dibutyl phthalate, butyl benzyl phthalate, di-2-ethylhexyl phthalate and the like can be used. In addition, citrate plasticizers such as acetyltributyl citrate, epoxidized oil plasticizers, and the like can also be used.

《Sugar ester compound》
The cellulose ester film of the present invention may be obtained by melt-forming a molten composition containing a sugar ester compound 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. preferable.

  Examples of the sugar compound of the present invention include glucose, galactose, mannose, fructose, xylose, arabinose, lactose, sucrose, cellobiose, cellotriose, maltotriose, raffinose, etc., particularly those having both a furanose structure and a pyranose structure. preferable. An example is sucrose.

  In the sugar ester compound of the present invention, part or all of the hydroxyl groups of the sugar compound are esterified with a carboxylic acid such as acetic acid, propionic acid, butyric acid, and benzoic acid. Esterification may be carried out with one kind of carboxylic acid or with two or more kinds of mixed acids.

《Acrylic polymer》
In the present invention, in order to adjust the optical properties in addition to the additive, it is preferable to melt and form a molten composition containing an acrylic polymer having a weight average molecular weight of 500 to 350,000.

  Specific examples of the acrylic polymer include acrylic acid esters such as methyl acrylate, ethyl acrylate, and butyl acrylate, and methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, and 2-hydroxyethyl methacrylate. A homopolymer or copolymer having an acid ester as a main component can be given. Moreover, it is also preferable to contain vinyls such as N-vinylpyrrolidone, styrenes such as styrene and 4-hydroxystyrene, acrylamides such as acryloylmorpholine, and the like as copolymerization components.

  These polymer plasticizers may be a homopolymer composed of one type of repeating unit or a copolymer having a plurality of repeating structures. Two or more of the above polymers may be used in combination.

<< Antioxidant, Heat degradation inhibitor >>
In the present invention, as an antioxidant and a thermal degradation inhibitor, generally known degradation inhibitors (antioxidants, peroxide decomposition agents, radical inhibitors, metal deactivators, acid scavengers, amines, etc.) ) Can be used. In particular, lactone, sulfur, phenol, double bond, hindered amine, and phosphorus compounds can be preferably used. The deterioration preventing agents are described in JP-A-3-199201, JP-A-5-1907073, JP-A-5-194789, JP-A-5-271471, and JP-A-6-107854.

  As said phenol type compound, what has the structure of 2, 6- dialkylphenol is preferable, for example, what is marketed by the brand name Irganox1076 and Irganox1010 from Ciba Japan KK is preferable.

  The phosphorous compounds are, for example, Sumitomo Chemical Co., Ltd., Sumilizer GP, ADEKA Co., Ltd., ADK STAB PEP-24G, ADK STAB PEP-36 and ADK STAB 3010, Ciba Japan Co., Ltd. IRGAFOS P-EPQ, What is marketed with the brand name of GSY-P101 from Sakai Chemical Co., Ltd. is preferable.

  As the hindered amine compound, for example, those commercially available from Ciba Japan Co., Ltd. under the trade names of Tinuvin 144 and Tinuvin 770 and ADEKA Co., Ltd. as ADK STAB LA-52 are preferable.

  The sulfur compound is preferably commercially available from Sumitomo Chemical Co., Ltd. under the trade names Sumilizer TPL-R and Sumilizer TP-D.

  The above-mentioned double bond compounds are preferably those commercially available from Sumitomo Chemical Co., Ltd. under the trade names Sumilizer GM and Sumilizer GS.

  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.

  The amount of these antioxidants and the like to be added is appropriately determined in accordance with the process for recycling and use, but is generally in the range of 0.05 to 5% by mass relative to the resin that is the main raw material of the film. Is added.

  These antioxidants and thermal deterioration inhibitors 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 modifier>
The cellulose ester film of the present invention may contain a compound for adjusting the retardation.

  As a compound to be added for adjusting the retardation, an aromatic compound having two or more aromatic rings as described in EP 911,656A2 can be used.

  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.

  Various dyes and pigments can be used as the colorant, but anthraquinone dyes, azo dyes, phthalocyanine pigments and the like are effective.

《Other additives》
In addition to the above compounds, the cellulose ester film of the present invention can contain an additive that can be added to a normal cellulose ester film.

  Examples of these additives include ultraviolet absorbers and fine particles.

  The ultraviolet absorber used in the present invention is excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less from the viewpoint of preventing deterioration of the liquid crystal, and has a small absorption of visible light having a wavelength of 400 nm or more from the viewpoint of good liquid crystal display properties. Is preferably used. In the present invention, the transmittance at a wavelength of 370 nm is particularly preferably 10% or less, more preferably 5% or less, and further preferably 2% or less.

  As the ultraviolet absorber added to the cellulose ester film of the present invention, an ultraviolet absorber having two or more aromatic rings in the molecule is particularly preferably used.

  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. The UV absorber preferably used in the present invention is preferably a benzotriazole-based UV absorber or a benzophenone-based UV absorber that has high transparency and is excellent in the effect of preventing the deterioration of the polarizing plate and the liquid crystal element, and has less unnecessary coloring. Benzotriazole ultraviolet absorbers are particularly preferred. As specific examples of the ultraviolet absorber used in the present invention, for example, TINUVIN109, TINUVIN171, TINUVIN326, TINUVIN327, TINUVIN328, TINUVIN900, TINUVIN928, ADEKA Corporation, LA-31 manufactured by Ciba Japan Co., Ltd. are preferably used. However, the present invention is not limited to these. As the UV absorber, a polymer UV absorber can also be preferably used, and in particular, a polymer type UV absorber described in JP-A-6-148430 is preferably used. An ultraviolet absorber may be used independently and 2 or more types of mixtures may be sufficient as it.

  The amount of the UV absorber used is not uniform depending on the type of compound, use conditions, etc., but when the dry film thickness of the cellulose ester film is 30 to 200 μm, 0.5 to 4.0 mass relative to the cellulose ester film. % Is preferable, and 0.6 g to 3.5% by mass is more preferable.

  As fine particles used in the present invention, 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 hydrated silicic acid. Mention may be made of calcium, aluminum silicate, magnesium silicate and calcium phosphate.

  Fine particles containing silicon are preferable in terms of low turbidity, and silicon dioxide is particularly preferable. The matting agent fine particles are preferably surface-treated with an organic material because the haze of the film can be reduced. Preferred organic materials for the surface treatment include halosilanes, alkoxysilanes, silazanes, siloxanes, and the like.

  The larger the average diameter of the fine particles, the greater the mat effect, and the smaller the average diameter, the better the transparency. Therefore, in the present invention, the average particle diameter of the primary particles of the fine particles is preferably 5 to 50 nm, and more preferably 7 ~ 20 nm. These are preferably contained mainly as secondary aggregates having a particle size of 0.05 to 0.3 μm.

  The content of these fine particles in the cellulose ester film is preferably 0.05 to 1% by mass, particularly preferably 0.1 to 0.5% by mass. In the case of a cellulose ester film having a multilayer structure by the co-casting method, it is preferable to contain fine particles of this addition amount on the surface.

  As the fine particles of silicon dioxide, for example, trade names such as Aerosil R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600, NAX50 (manufactured by Nippon Aerosil Co., Ltd.) can be used.

  Zirconium oxide fine particles are commercially available, for example, under the trade names Aerosil R976 and R811 (manufactured by Nippon Aerosil Co., Ltd.) and can be used.

  Examples of the polymer include silicone resin, fluororesin, and acrylic resin. Silicone resins are preferable, and those having a three-dimensional network structure are particularly preferable. For example, Tospearl 103, 105, 108, 120, 145, 3120, and 240 (manufactured by Toshiba Silicone Co., Ltd.) It is marketed by name and can be used.

  Among these, Aerosil 200V and Aerosil R972V are particularly preferably used because they have a large effect of reducing the friction coefficient while keeping the turbidity of the cellulose ester film low.

<Melt film forming method>
The optical film of the present invention is formed by melt casting. In the present application, “melt film formation” means that a composition containing additives such as a cellulose ester and a plasticizer is heated and melted to a temperature showing fluidity, and then a melt containing the flowable cellulose ester is cast. It is defined as to do.

  Molding methods that are heated and melted without using a solvent (such as methylene chloride) used in the solution casting method include melt extrusion molding method, press molding method, inflation method, injection molding method, blow molding method, stretch molding method, etc. Can be classified. Among these, in order to obtain a cellulose ester film excellent in mechanical strength and surface accuracy, the melt extrusion molding method is excellent.

  Hereinafter, the manufacturing method of the optical film of the present invention will be described by taking the melt extrusion molding method as an example. In the method for producing an optical film, the conditions for melt extrusion can be performed in the same manner as the conditions used for other thermoplastic resins such as polyester.

<< Melted pellet manufacturing process 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.

  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, kneaded using a single or twin screw extruder, and extruded from a die into a strand. Can be done by water cooling or air cooling and cutting.

  Matting agents, UV absorbers, and the like may be prepared as high-concentration master pellets and mixed with main pellets in an extruder during film formation.

  It is important to dry the raw material before extruding to prevent decomposition of the raw material. In particular, since the cellulose ester is easy to absorb 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 to keep the moisture content at 200 ppm or less, and further 100 ppm or less.

  The additives may be mixed before being supplied to the extruder, or may be supplied by individual feeders. A small amount of an additive such as an antioxidant is preferably mixed in advance in order to mix uniformly.

  A vacuum nauter mixer or the like is preferable because drying and mixing can be performed simultaneously. Moreover, when contacting with air, such as an exit from a feeder part or die, it is preferable that the atmosphere be dehumidified air or dehumidified nitrogen gas.

  In addition, it is preferable to keep the supply hopper and the like to the extruder warm because moisture absorption can be prevented.

  The extruder is preferably processed at as low a temperature as possible so that the shearing force is suppressed and the resin can be pelletized so as not to 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.

  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 color of the pellet is preferably such that the b ^* value, which is an index of yellowness, is in the range of -5 to 10, more preferably in the range of -1 to 8, and in the range of -1 to 5. More preferred. The b ^* value can be measured at a viewing angle of 10 ° using a spectrocolorimeter CM-3700d (manufactured by Konica Minolta Sensing Co., Ltd.) and a light source of D65 (color temperature 6504K).

  It is preferable to form a film using the pellets obtained as described above. Without forming into pellets, the raw material powder can be supplied as it is to the extruder with a feeder to form a film.

<Process for extruding melt of cellulose ester and additive from die>
It is preferable to dry materials such as pellets in advance. It is desirable to dry the moisture to 200 ppm or less, preferably 100 ppm or less using a vacuum or reduced pressure drier or a dehumidifying hot air drier.

  The polymer dried under dehumidified hot air, vacuum or reduced pressure is melted using a uniaxial or biaxial extruder, filtered through a leaf disk type filter, etc. to remove foreign matter, and then cast into a film from a fluted die. And solidify on a cooling roll.

  Various extruders available on the market can be used as the extruder, but a melt-kneading extruder is preferable, and a single-screw extruder or a twin-screw extruder may be used.

  It is preferable from the viewpoint of suppressing oxidative decomposition that the portion introduced from the supply hopper to the extruder and the inside of the extruder are replaced with an inert gas such as nitrogen gas or reduced in pressure to reduce the oxygen concentration.

  The melting temperature of the optical film constituent material in the extruder varies depending on the viscosity and discharge amount of the optical film constituent material, the thickness of the sheet to be produced, etc., but is preferably 150 to 300 ° C, more preferably 180 to 270 ° C, 200-260 degreeC is further more preferable. If the temperature is too low, poor dissolution and an increase in melt viscosity occur, and if the temperature is too high, thermal decomposition of the material occurs.

  The melt viscosity at the time of extrusion is 10 to 100,000 poise, preferably 100 to 10,000 poise. If the melt viscosity is too high, the residence time in the extruder becomes longer due to an increase in pressure. The residence time of the optical film constituting material in the extruder is preferably shorter, and is within 5 minutes, preferably within 3 minutes, more preferably within 2 minutes.

  The residence time depends on the type of extruder and the extrusion conditions, but it can be shortened by adjusting the material supply amount, L / D, screw rotation speed, screw groove depth, etc. is there.

  The shape of the screw and the number of rotations of the extruder are appropriately selected depending on the viscosity and the discharge amount of the optical film constituting material. In the present invention, the shear rate in the extruder is from 1 / second to 10000 / second, preferably from 5 / second to 1000 / second, and more preferably from 10 / second to 100 / second.

  The molten resin extruded from the extruder is sent to a casting die and extruded from the slit of the casting die into an optical film. The casting die is not particularly limited as long as it is used for producing a sheet or an optical film.

  As the material of the casting die, hard chromium, chromium carbide, chromium nitride, titanium carbide, titanium carbonitride, titanium nitride, super steel, ceramic (tungsten carbide, aluminum oxide, chromium oxide), etc. are sprayed or plated and surface processed Buffing, lapping using a # 1000 or higher whetstone, surface cutting using a diamond whetstone of # 1000 or higher (the cutting direction is perpendicular to the resin flow direction), electrolytic polishing, electrolytic composite polishing, etc. And the like. The preferred material of the lip portion of the casting die is the same as that of the casting die 4. The surface accuracy of the lip is preferably 0.5S or less, and more preferably 0.2S or less.

  The slit of the casting die is configured so that the gap can be adjusted.

  Of the pair of lips forming the slit of the casting die, one is a flexible lip having low rigidity and easily deformed, and the other is a fixed lip.

  A large number of heat bolts are arranged at a constant pitch in the width direction of the casting die. Each heat bolt is provided with a block having an embedded electric heater and a cooling medium passage, and each heat bolt vertically penetrates each block.

  The base of the heat bolt is fixed to the die body, and the tip is in contact with the outer surface of the flexible lip. Then, while constantly cooling the block, the input of the embedded electric heater is increased or decreased to raise or lower the temperature of the block, thereby thermally expanding and contracting the heat bolt, and displacing the flexible lip to adjust the thickness of the optical film.

  Thickness gauges are installed at the required locations in the wake of the die, and the web thickness information detected thereby is fed back to the control device. The thickness information is compared with the set thickness information by the control device, and correction control comes from the same device. It is also possible to control the power or the ON rate of the heat bolt heating element by the amount signal.

  The heat bolt preferably has a length of 20 to 40 cm and a diameter of 7 to 14 mm, and a plurality of, for example, several tens of heat bolts are preferably arranged at a pitch of 20 to 40 mm.

  Instead of the heat bolt, a gap adjusting member mainly composed of a bolt for adjusting the slit gap by manually moving back and forth in the axial direction may be provided.

  The slit gap adjusted by the gap adjusting member is usually 200 to 2000 μm, preferably 300 to 1000 μm, more preferably 400 to 800 μm.

  The extrusion flow rate is preferably performed stably by introducing a gear pump or the like. Further, a stainless fiber sintered filter is preferably used as a filter used for removing foreign substances.

  A stainless steel fiber sintered filter is a united stainless steel fiber body that is intricately entangled and then compressed and sintered at the contact location. The density is changed according to the thickness of the fiber and the amount of compression, and the filtration accuracy is improved. Can be adjusted.

  The filter is preferably a multilayer body formed by combining filter media having different filtration accuracy. 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 supplementing foreign matters and gels can be improved.

  If flaws or foreign matter adhere to the die, streaky defects may occur. Such a defect is called a die line, but in order to reduce surface defects such as the die line, it is preferable to have a structure in which the resin retention portion is minimized in the piping from the extruder to the die. . It is preferable to use a die that has as few scratches as possible inside the lip.

  The inner surface that contacts 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 having a 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.

  Additives such as plasticizers may be mixed with the resin in advance, or may be kneaded in the middle of the extruder. In order to add uniformly, it is preferable to use a mixing apparatus such as a static mixer.

《Cooling roll》
The cooling roll of the present invention is not particularly limited, but is a roll having a structure with a high-rigidity metal roll that allows a temperature-controllable heat medium or refrigerant to flow inside, and is not limited in size. It is sufficient that the film is large enough to cool the formed film, and the diameter of the cooling roll is usually about 100 mm to 1 m.

  Examples of the surface material of the cooling roll include carbon steel, stainless steel, aluminum, and titanium. Further, in order to increase the surface hardness or improve the releasability from the resin, it is preferable to carry out a surface treatment such as hard chrome plating, nickel plating, amorphous chrome plating, or ceramic spraying.

  The cooling roll is made of a seamless steel pipe having a wall thickness of about 20 to 30 mm, and the surface is finished to a mirror surface.

  The surface roughness of the surface of the cooling roll is preferably 0.1 μm or less in terms of Ra, and more preferably 0.05 μm or less. The smoother the roll surface, the smoother the surface of the resulting film. Of course, it is preferable to further polish the surface that has been subjected to surface processing so as to have the surface roughness described above.

  The cooling roll of the present invention is at least one, and preferably has two or more. When there is only one, the surface temperature Tr of the cooling roll is set to Tg-50 ≦ Tr ≦ Tg. In the case of two or more, the surface temperatures of the first cooling roll and the second cooling roll are set to Tg−50 ≦ Tr1 ≦ Tg and Tg−50 ≦ Tr2 ≦ Tg.

  Preferably, Tr2> Tr1, and 0 <Tr2-Tr1 <50.

  As a result, the amount of the additive on the cooling roll is controlled, and the cellulose film is remelted.

  Although re-dissolution can be promoted by the contact time between the cellulose ester film and the first and second cooling rolls, in the present invention, 1.0 second or more and 3.0 seconds or less are preferable.

  The contact time was represented by the number of seconds calculated from the circumferential distance between the contact point at which the film and the roller began to contact and the contact point at which the film began to peel, and the film conveyance speed.

  The circumferential speed R2 of the second cooling roll is preferably larger than the circumferential speed R1 of the first cooling roll. That is, tension acts on the film between the two rolls, and the adhesion between the film and the first roll is increased. The ratio of the peripheral speeds is preferably in the range of 1.00 to 1.05, and if it exceeds 1.05, there is a risk that the film breaks. Similarly, it is preferable that the third and subsequent roll peripheral speeds are greater than the peripheral speed of the cooling roll immediately before.

《Elastic touch roll》
The touch roll that abuts on the cooling roll has an elastic surface, and can be deformed along the surface of the cooling roll by a pressing force to the cooling roll to form a nip with the cooling roll. It is preferable that

  As the elastic touch roll of the present invention, Japanese Patent No. 3194904, Japanese Patent No. 3422798, Japanese Patent Application Laid-Open No. 03-124425, Japanese Patent Application Laid-Open No. 08-224772, Japanese Patent Application Laid-Open No. 07-1000096, Japanese Patent Application Laid-Open No. 10-272676, WO 97- Elastic touch rolls as described in Japanese Patent No. 028950, Japanese Patent Application Laid-Open No. 11-235747, Japanese Patent Application Laid-Open No. 2002-36332, Japanese Patent Application Laid-Open No. 2002-36333, Japanese Patent Application Laid-Open No. 2005-172940, and Japanese Patent Application Laid-Open No. 2005-280217. Can be used.

  The elastic touch roll used in the present invention has a double structure of a metal outer cylinder and an inner cylinder, and has a space so that a cooling fluid can flow between them.

  Furthermore, because the metal outer cylinder has elasticity, the temperature of the surface of the touch roll can be controlled with high accuracy, and the distance to press the film in the longitudinal direction can be increased by utilizing the property of elastically deforming appropriately. With this effect, the effect of the present invention can be obtained that there are no bright and dark stripes and uneven spots when an image is displayed on a liquid crystal display device.

  If the range of the thickness of the metal outer cylinder is 0.003 ≦ (thickness of the metal outer cylinder) / (touch roll radius) ≦ 0.03, it is preferable because the elasticity is appropriate. If the radius of the touch roll is large, even if the thickness of the metal outer cylinder is thick, the touch roll can be appropriately bent. If the thickness of the metal outer cylinder is too thin, the strength is insufficient and there is a concern of breakage. On the other hand, if it is too thick, the roll mass becomes too heavy and there is a concern about uneven rotation. Therefore, the thickness of the metal outer cylinder is preferably 0.1 to 5 mm.

  The elastic touch roll has a diameter of 100 mm to 600 mm, an effective roll width L = 500 to 1600 mm, and preferably has a horizontally long shape with r / L <1.

  The surface roughness of the surface of the metal outer cylinder is preferably 0.1 μm or less in terms of arithmetic average roughness Ra, and more preferably 0.05 μm or less. The smoother the roll surface, the smoother the surface of the resulting film.

  The material of the metal outer cylinder is required to be smooth, moderately elastic, and durable. Carbon steel, stainless steel, titanium, nickel produced by electroforming, etc. can be preferably used. Further, in order to increase the hardness of the surface or improve the releasability from the resin, it is preferable to carry out a surface treatment such as hard chrome plating, nickel plating, amorphous chrome plating, or ceramic spraying. It is preferable that the surface processed is further polished to have the surface roughness described above.

  The inner cylinder is preferably a lightweight and rigid metallic inner cylinder such as carbon steel, stainless steel, aluminum, titanium or the like. By giving rigidity to the inner cylinder, it is possible to suppress the rotational shake of the roll. A sufficient rigidity can be obtained by setting the thickness of the inner cylinder to 2 to 10 times that of the outer cylinder.

  The inner cylinder may be further coated with a resin elastic material such as silicone or fluororubber.

  The structure of the space through which the cooling fluid flows can be any structure as long as the temperature of the roll surface can be controlled uniformly. Temperature control with a small surface temperature distribution is possible.

  The cooling fluid is not particularly limited, and water or oil can be used according to the temperature range to be used.

  The surface temperature Tr0 of the elastic touch roll is preferably lower than the glass transition temperature (Tg) of the film. If it is higher than Tg, the peelability between the film and the roll may be inferior. More preferably, it is Tg-50 degreeC-Tg.

  The elastic touch roll used in the present invention preferably has a so-called crown roll shape in which the central portion in the width direction has a diameter larger than that of the end portion.

  The touch roll generally presses both ends of the touch roll against the film with a pressurizing unit, but in this case, the touch roll is bent, so that there is a phenomenon that the touch roll is pressed more strongly toward the end. By making the roll into a crown shape, highly uniform pressing becomes possible.

  The width of the elastic touch roll used in the present invention is preferably wider than the film width because the entire film can be in close contact with the cooling roll. Further, when the draw ratio is increased, both end portions of the film may become ear height (thickness of the end portion becomes thick) due to a neck-in phenomenon.

  In this case, the width of the metal outer cylinder may be made narrower than the film width so as to escape from the height of the ear. Alternatively, the outer diameter of the metal outer cylinder may be reduced to escape the ear height.

  In order to prevent bending of the elastic touch roll, a support roll may be arranged on the opposite side of the touch roll with respect to the cooling roll.

  You may arrange | position the apparatus which cleans the dirt of an elastic touch roll. As the cleaning device, for example, a method of pressing the roll surface with a member such as a nonwoven fabric infiltrated with a solvent if necessary, a method of bringing the roll into contact with a liquid, a plasma discharge such as corona discharge or glow discharge, A method for volatilizing dirt can be preferably used.

  In order to make the surface temperature Tr0 of the elastic touch roll even more uniform, a temperature control roll may be brought into contact with the touch roll, temperature-controlled air may be blown, or a heat medium such as a liquid may be brought into contact.

  In the present invention, it is preferable that the touch roll linear pressure when pressing the elastic touch roll is 9.8 N / cm or more and 147 N / cm or less. If the linear pressure is smaller than this range, the die line cannot be sufficiently eliminated.

  The linear pressure is a value obtained by dividing the force with which the elastic touch roll presses the film by the film width at the time of pressing. The method for setting the linear pressure within the above range is not particularly limited, and for example, both ends of the roll can be pressed with an air cylinder or a hydraulic cylinder.

  You may press a film indirectly by pressing an elastic touch roll with a support roll.

  In order to satisfactorily eliminate the die line by the touch roll, it is important that the viscosity of the optical film when the touch roll sandwiches the optical film is in an appropriate range.

  Cellulose esters are known to have a relatively large change in viscosity with temperature.

  When the glass transition temperature of the optical film is defined as Tg, the touch roll side film surface temperature Tt immediately before the extruded film is sandwiched between the touch rolls is preferably Tg <Tt <Tg + 110 ° C.

  That is, when the film temperature Tt immediately before being sandwiched between the touch rolls is within the above range, the viscosity of the film when sandwiching the film can be set to an appropriate range, and the die line can be corrected. The film surface and the roll are bonded uniformly, and the die line can be corrected.

  Preferably Tg + 10 ° C. <Tt <Tg + 90 ° C., more preferably Tg + 20 ° C. <Tt <Tg + 70 ° C.

  The method of setting the film temperature at the time of pressing in the above range is not particularly limited. For example, the distance between the die and the cooling roll is made closer, and the cooling between the die and the cooling roll is suppressed, or between the die and the cooling roll. Examples of the method include heat insulation by surrounding with a heat insulating material, or heating by hot air, an infrared heater, microwave heating, or the like.

  The film surface temperature and roll surface temperature can be measured with a non-contact infrared thermometer. Specifically, using a non-contact handy thermometer (IT2-80, manufactured by Keyence Co., Ltd.), 10 locations in the width direction of the film are measured at a distance of 0.5 m from the object to be measured.

  The elastic touch roll side film surface temperature Tt refers to the film surface temperature measured with a non-contact infrared thermometer from the touch roll side in the state where the touch roll is removed from the film being conveyed.

  The image clarity C value of the cellulose ester film of the present invention is characterized in that it is 90 or more and 100 or less in transmission measurement of comb teeth of 0.125 mm. This image clarity C value is the image clarity when it passes through the last cooling roll.

  The image clarity after passing through the cooling roll has a correlation as an index representing the state of the cellulose ester film in which the aggregate is remelted on the film surface. It has been experimentally confirmed that the larger the C value is, the more the remelting proceeds.

  The image clarity C value represents the image clarity (gloss value C value%) measured by a transmission (0 degree) measurement with an image measurement instrument ICM-IDP of Suga Test Instruments Co., Ltd. and an optical comb tooth of 0.125 mm.

<< The process of casting while pressing the melt extruded from the die between the cooling roll and the elastic touch roll >>
In the present invention, the die line correction effect is more greatly manifested by reducing the pressure from the opening (lip) of the casting die to the cooling roll to 70 kPa or less.

  The reduced pressure is preferably 50 to 70 kPa. There is no particular limitation on the method of keeping the pressure in the portion from the opening (lip) of the casting die to the cooling roll at 70 kPa or less. is there.

  At this time, the suction device is preferably subjected to a treatment such as heating with a heater so that the device itself does not become a place where the sublimate is attached. In the present invention, if the suction pressure is too small, the sublimate cannot be sucked effectively, so it is necessary to set the suction pressure to an appropriate value.

  A melt containing cellulose ester has a higher melt viscosity and is less likely to be stretched than other thermoplastic resins.

  Therefore, when the draw ratio is large, there is a problem that the film thickness is likely to vary in the conveying direction, and also when the film is stretched in the tenter process, the film tends to be broken, and the drawing ratio is about 7 to 8 at most. However, in the present invention, a melt containing cellulose ester is extruded from a die into a film shape, and a film obtained with a draw ratio of 10 or more and 30 or less is conveyed while being pressed against a cooling roll with an elastic touch roll.

  The draw ratio is a value obtained by dividing the lip clearance of the die by the average film thickness of the film solidified on the cooling roll. By setting the draw ratio within this range, a polarizing plate protective film having good productivity and no bright and dark stripes and uneven spots when an image is displayed on a liquid crystal display device can be obtained.

  The draw ratio can be adjusted by the die lip clearance and the take-up speed of the cooling roll. The die lip clearance is preferably 900 μm or more, and more preferably 1 mm or more and 2 mm or less. Even if it is too large or too small, spotted unevenness may not be improved.

  It is preferable to adjust the film temperature on the touch roll side when the film is nipped between the cooling roll and the elastic touch roll to Tg + 110 ° C. or less of the film in order to adjust the image clarity of the film surface. A well-known roll can be used for the roll which has the elastic body surface used for such a purpose.

  When peeling the film from the cooling roll, it is preferable to control the tension to prevent deformation of the film.

《Roll cleaning equipment》
It is preferable to add a device for automatically cleaning the drum and roll to the manufacturing apparatus of the present invention. There is no particular limitation on the cleaning device, but for example, a method of niping a brush roll, a water absorbing roll, an adhesive roll, a wiping roll, an air blow method of spraying clean air, a laser incinerator, or a combination thereof. is there.

  In the case where the cleaning roll is nipped, the cleaning effect is great if the belt linear velocity and the roller linear velocity are changed.

<< Extension process >>
In the present invention, it is preferred that the film obtained as described above is further stretched by 1.01 to 3.0 times in at least one direction after passing through the step of contacting the cooling roll. Stretching can improve surface quality, such as streaking, and adjust retardation.

  Preferably, the film is stretched 1.1 to 2.0 times in both the longitudinal (film transport direction) and lateral (width direction) directions.

  As a method of stretching, a known roll stretching machine or tenter can be preferably used.

  When the cellulose ester film of the present invention is used as a film having an optical compensation function, the temperature and magnification can be selected so that desired retardation characteristics can be obtained.

  Usually, the draw ratio is 1.01 to 3.0 times, preferably 1.1 to 2.0 times, and the draw temperature is usually Tg to Tg + 50 ° C., preferably Tg to Tg + 40 ° C. of the resin constituting the film. In the temperature range.

  If the draw ratio is too small, the streak may not be improved sufficiently, or a desired retardation may not be obtained, and if it is too large, it may break. If the stretching temperature is too low, it may break, and if it is too high, the streak may not be improved sufficiently, or 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.

  In the stretching step, known heat setting conditions, cooling, and relaxation treatment may be performed, and adjustment may be made as appropriate so as to have characteristics required for the intended film.

  In order to provide the physical properties of the phase film and the function of the phase film for expanding the viewing angle of the liquid crystal display device, the stretching step and the heat setting treatment are appropriately selected and performed. When such a stretching step and heat setting treatment are included, the heating and pressurizing step is performed before the stretching step and heat setting treatment.

  For the purpose of reducing the retardation of the cellulose ester film produced by the above method and reducing the dimensional change rate, the film may be contracted in the longitudinal direction or the width direction.

  In order to shrink in the longitudinal direction, for example, there is a method in which the film is shrunk by temporarily clipping out the width stretching and relaxing in the longitudinal direction, or by gradually narrowing the interval between adjacent clips of the transverse stretching machine.

  The latter method can be performed by using a general simultaneous biaxial stretching machine and driving the clip portions in the longitudinal direction by, for example, a pantograph method or a linear drive method to smoothly and gradually narrow the clip portion. it can. You may combine with extending | stretching of arbitrary directions (diagonal direction) as needed. The dimensional change rate of the optical film can be reduced by shrinking 0.5% to 10% in both the longitudinal direction and the width direction.

  Since the elastic modulus of the film can be increased by stretching, the stretching is effective as a means for compensating for the low elastic modulus of the melt-formed cellulose ester film. Moreover, it turned out that the contact angle of the cellulose-ester film melt-formed by extending | stretching falls. This is presumably because the polar group that had submerged inside the film emerges on the surface as a result of the surface area per volume being increased by stretching the film.

  When a retardation film is produced as an optical film and the functions of a polarizing plate protective film are combined, it is necessary to control the refractive index. However, the refractive index can be controlled by a stretching operation.

  In the retardation film stretching process, it is required by stretching 1.0 to 2.0 times in one direction of the cellulose resin and 1.01 to 2.5 times in the direction perpendicular to the optical film plane. Retardation Ro and Rth can be controlled. Here, Ro indicates in-plane retardation, and Rth indicates thickness direction retardation.

  In the case of having a phase difference function, Ro is 20 to 200 nm, Rth is 90 to 400 nm, and the ratio Rth / Ro of Rth and Ro is preferably 0.5 to 4, particularly preferably 1 to 3.

In addition, when the refractive index Nx in the slow axis direction of the film, the refractive index Ny in the fast axis direction, the refractive index Nz in the thickness direction, and the film thickness of the film are d (nm),
Ro = (Nx−Ny) × d
Rth = {(Nx + Ny) / 2−Nz} × d
Represented as: (Measurement wavelength 590nm)
The variation in retardation is preferably as small as possible, and is usually within ± 10 nm, preferably ± 5 nm or less, and more preferably ± 2 nm or less.

  The uniformity in the slow axis direction is also important, and the angle θ1 is preferably in the range of −1 to + 1 °, and more preferably in the range of −0.5 to + 0.5 ° with respect to the film width direction. Is preferable, and is particularly preferably in the range of −0.1 to + 0.1 °. These variations can be achieved by optimizing the stretching conditions.

  This θ1 can be defined as an orientation angle, and the measurement of θ1 can be performed using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments).

  Each of θ1 satisfying the above relationship contributes to suppressing or preventing light leakage, and contributes to faithful color reproduction in a color liquid crystal display device.

  The retardation Ro distribution in the in-plane direction of the retardation film is preferably adjusted to 5% or less, more preferably 2% or less, and particularly preferably 1.5% or less.

  The retardation Rth distribution in the thickness direction of the optical film is preferably adjusted to 10% or less, more preferably 2% or less, and particularly preferably 1.5% or less.

  In the retardation film, it is preferred that the retardation value distribution fluctuation is small. When a polarizing plate including a retardation film is used in a liquid crystal display device, the retardation distribution fluctuation is preferably small from the viewpoint of preventing color unevenness and the like. .

  Stretching can be performed, for example, sequentially or simultaneously in the longitudinal direction of the optical film and the direction orthogonal to the longitudinal direction of the optical film, that is, the width direction.

  By stretching in the biaxial directions perpendicular to each other, film thickness variation of the obtained optical film can be reduced. When the film thickness variation of the retardation film is too large, the retardation becomes uneven, and unevenness such as coloring may be a problem when used in a liquid crystal display.

  The film thickness variation of the optical film is preferably in the range of ± 3%, and more preferably ± 1%. For the purposes as described above, a method of stretching in the biaxial directions orthogonal to each other is effective, and the stretching ratio in the biaxial directions orthogonal to each other is finally 1.0 to 2.0 times in the casting direction. The width direction is preferably 1.01 to 2.5 times, the casting direction is 1.01 to 1.5 times, and the width direction is 1.05 to 2.0 times. It is more preferred to obtain the required retardation value.

  After stretching, the edge of the optical film is slit to a product width with a slitter and cut off, and then subjected to knurling (embossing) on both ends of the optical film by a knurling device comprising an embossing ring and a back roll. By taking up with a take-up machine, sticking in an optical film (original winding) and generation of scratches are prevented. The knurling method can process a metal ring having an uneven pattern on its side surface by heating or pressing.

  In addition, since the grip part of the clip of the optical film both ends is deform | transforming normally and cannot be used as an optical film product, it is cut out and reused as a raw material.

  Next, the winding process of the optical film is performed by keeping the shortest distance between the outer peripheral surface of the cylindrically wound optical film and the outer peripheral surface of the mobile transport roll immediately before the optical film as a winding roll. It is to be wound up. In addition, a means such as a static elimination blower for removing or reducing the surface potential of the optical film is provided in front of the winding roll.

  The winder related to the production of the optical film of the present invention may be generally used, and it may be a winding method such as a constant tension method, a constant torque method, a taper tension method, or a program tension control method with a constant internal stress. Can be wound up. In addition, it is preferable that the initial winding tension at the time of winding of the optical film is 90.2 to 300.8 N / m.

  In the winding process of the optical film in the method of the present invention, the optical film is preferably wound under environmental conditions of a temperature of 20 to 30 ° C. and a humidity of 20 to 60% RH.

  Thus, by specifying the temperature and humidity in the winding process of the optical film, the resistance to humidity change of the thickness direction retardation (Rth) is improved.

  If the temperature in the winding process is in the range of 20 to 30 ° C., there will be no wrinkles and there will be no deterioration of the optical film winding quality.

  Moreover, if the humidity in the winding process of the optical film is 20 to 60% RH, it is difficult to be charged, the optical film winding quality deterioration is reduced, the winding quality is excellent, there is no sticking failure, and the transportability is not deteriorated. .

  When winding the optical film into a roll, the wound core may be any material as long as it is a cylindrical core, but is preferably a hollow plastic core, and the plastic material is heated. Any heat-resistant plastic that can withstand the processing temperature may be used, and examples thereof include phenol resins, xylene resins, melamine resins, polyester resins, and epoxy resins.

  A thermosetting resin reinforced with a filler such as glass fiber is preferred. For example, a hollow plastic core: a wound core made of FRP having an outer diameter of 6 inches (hereinafter, 1 inch is 2.54 cm) and an inner diameter of 5 inches is used.

  The number of turns to these winding cores is preferably 100 turns or more, more preferably 500 turns or more, the winding thickness is preferably 5 cm or more, and the width of the optical film substrate is 80 cm or more. It is preferable that it is 1 m or more.

  In the production of the optical film of the present invention, the length of the roll is preferably 10 to 5000 m, more preferably 50 to 4500 m in consideration of productivity and transportability.

  The width of the optical film at this time can be selected from the width of the polarizer and the width suitable for the production line, but the optical film has a width of 0.5 to 4.0 m, preferably 0.6 to 3.0 m. Is preferably wound up into a roll.

  In the cellulose ester film of the present invention, it is preferable that the height from the top of the adjacent mountain to the bottom of the valley is 300 nm or more, and there is no streak continuous in the longitudinal direction with an inclination of 300 nm / mm or more.

  The shape of the streak was measured using a surface roughness meter. Specifically, using a Mitutoyo SV-3100S4, a stylus (diamond needle) with a tip shape of 60 ° cone and a tip curvature radius of 2 μm was used. The film is scanned in the width direction of the film at a measurement speed of 1.0 mm / sec while applying a load of 0.75 mN, and a cross-sectional curve is measured with a Z-axis (thickness direction) resolution of 0.001 μm.

  From this curve, the streak height reads the vertical distance (H) from the top of the mountain to the bottom of the valley. The slope of the streak is obtained by reading the horizontal distance (L) from the top of the mountain to the bottom of the valley and dividing the vertical distance (H) by the horizontal distance (L).

<Optical film>
In the present application, the “optical film” is a functional film used for various display devices such as a liquid crystal display, a plasma display, and an organic EL display. Specifically, a polarizing plate protective film, a retardation film for a liquid crystal display device, An antireflection film, a brightness enhancement film, a hard coat film, an antiglare film, an antistatic film, an optical compensation film for expanding the viewing angle, and the like.

  The film thickness of the optical film is preferably 10 to 200 μm, more preferably 25 to 90 μm. If the film is too thin than this range, the strength is insufficient, and if it is too thick, the productivity is lowered in the polarizing plate preparation process.

  The retardation film is adjusted to have a retardation value suitable for improving the display quality of the VA mode or TN mode liquid crystal cell, and is preferably used for the MVA mode by dividing the retardation film into the above multi-domain as the VA mode. To achieve this, it is required to adjust the in-plane retardation Ro to a value greater than 30 nm and 95 nm or less, and the thickness direction retardation Rth to a value greater than 70 nm and 400 nm or less.

  The above-mentioned in-plane retardation Ro is based on the case of observing from the normal direction of the display surface when two polarizing plates are arranged in crossed Nicols and a liquid crystal cell is arranged between the polarizing plates. In the crossed Nicol state, when observed obliquely from the normal of the display surface, the polarizing plate is displaced from the crossed Nicol state, and light leakage caused by this is mainly compensated.

  The retardation in the thickness direction mainly compensates for the birefringence of the liquid crystal cell similarly observed when viewed from an oblique direction when the liquid crystal cell is in a black display state in the TN mode or VA mode, particularly in the MVA mode. To contribute.

  In the liquid crystal display device, when two polarizing plates are arranged above and below the liquid crystal cell, the distribution of the thickness direction retardation Rth can be selected, and both the thickness direction retardation Rth satisfying the above range can be selected. The total value is preferably larger than 140 nm and 500 nm or less.

  In a liquid crystal display device, for example, a TAC film having an in-plane retardation Ro = 0 to 4 nm and a thickness direction retardation Rth = 20 to 50 nm and a thickness of 35 to 85 μm is used as one polarizing plate as a commercially available polarizing plate protective film. The retardation film disposed on the other polarizing plate has an in-plane retardation Ro of more than 30 nm and not more than 95 nm, and a thickness direction retardation Rth of more than 140 nm and not more than 400 nm. Thereby, display quality improves and it is preferable also from the production surface of an optical film.

  An optical film having a laminated structure can be prepared by co-extrusion of a composition containing cellulose esters having different additive concentrations such as the plasticizer, the ultraviolet absorber, and the matting agent.

  For example, an optical film having a structure of skin layer / core layer / skin layer can be produced.

  For example, the matting agent can be contained in the skin layer in a large amount or only in the skin layer. The plasticizer and the ultraviolet absorber can be contained in the core layer more than the skin layer, and may be contained only in the core layer.

  In addition, the type of plasticizer and ultraviolet absorber can be changed between the core layer and the skin layer. For example, the skin layer contains a low-volatile plasticizer and / or an ultraviolet absorber, and the core layer has excellent plasticity. It is also possible to add a plasticizer or an ultraviolet absorber excellent in ultraviolet absorption.

  The glass transition temperature of the skin layer and the core layer may be different, and the glass transition temperature of the core layer is preferably lower than the glass transition temperature of the skin layer.

  At this time, the glass transition temperatures of both the skin layer and the core layer are measured, and an average value calculated from these volume fractions can be defined as the glass transition temperature Tg and similarly handled.

  Also, the viscosity of the melt containing the cellulose ester during melt casting may be different between the skin layer and the core layer, and the viscosity of the skin layer> the viscosity of the core layer or the viscosity of the core layer ≧ the viscosity of the skin layer may be used.

《Functional layer》
The functional film of the present invention is characterized by having a hard coat layer on the surface of the cellulose ester film, and the functional layer is an embodiment having an antireflection layer to be described later in addition to the hard coat layer. May be.

  The “solubility parameter” according to the present invention is a measure of the miscibility between liquids. H. It is proposed by Hildebrand and is defined by the following equation. It is empirically known that the solubility increases as the difference in solubility parameters (Solubility Parameter, δ, SP value) of the two components decreases.

  The solubility parameter of the substance is defined by the following formula, where δE is the cohesive energy per mole and V is the molar volume.

SP = (δE / V) ^1/2
Similarly, the action of the solvent on the polymer substance can be explained by the solubility parameter. The solubility parameter of the polymer substance can be determined by examining the solubility of the polymer substance in a solvent having a known solubility parameter.

  This solubility parameter is described in J. Am. H. Hildebrand, J.M. M.M. Prausnitz. R. L. “Regular and Related Solutions” by Scott, Van Nostrand-Reinhold, Princeton (1970), “Polymer Data Handbook Fundamentals” Polymer Science Society can be referred to.

  In the present invention, specific numerical values of the solubility parameter according to the present invention are described in J. Org. BRANDRUP and E. H. Numerical values described in IMMERGUT, “POLYMER HANDBOOK”, THIRD EDITION, JOHN WILEY & SONS (1989) were used.

The unit of the solubility parameter is represented by (MPa) ^1/2 .

In the present invention, when a functional layer comprising at least a hard coat layer is directly coated on the cellulose ester film of the present invention, the solubility parameter (SP) in a functional layer coating liquid such as a hard coat layer coating liquid is used. A value containing 20 to 45% by mass of an organic solvent having a value of 18.5 to 21 (MPa) ^1/2 with respect to the coating solution is used.

Examples of the organic solvent having a solubility parameter of 18.5 to 21 (MPa) ^1/2 include the following organic solvents.

  Acetone (20.3), butyl lactate (19.2), cyclohexanone (20.3), diacetone alcohol (18.6), ethyl acetate (18.6), ethyl lactate (20.5), methyl acetate ( 19.6), methylcyclohexanone (19.0), methyl ethyl ketone (19.0), propylene glycol methyl ether (20.7), tetrahydrofuran (18.6).

The functional layer coating solution may contain an organic solvent other than an organic solvent having a solubility parameter of 18.5 to 21 (MPa) ^1/2 within a range not impairing the effects of the present invention. Examples of these organic solvents include hydrocarbons (toluene (18.2), xylene (18.0)), alcohols (methanol (29.7), ethanol (26.0), isopropanol (23.5). ), Butanol (23.3), cyclohexanol (23.3)), ketones (methyl isobutyl ketone (17.2)), glycol ethers, and other organic solvents, or a mixture thereof Available.

The solubility parameter of cellulose ester is about 19 to 20 (MPa) ^1/2 depending on the degree of substitution. Therefore, the organic solvent having a solubility parameter of 18.5 to 21 (MPa) ^1/2 is cellulose ester. Has the effect of dissolving or swelling. For this reason, if the solubility parameter of the organic solvent contained in the functional layer coating liquid is in the range of 18.5 to 21 (MPa) ^1/2 , the mixing of the interface between the functional layer and the cellulose ester film proceeds. The adhesive strength of the functional film is improved, and interference fringes are hardly seen, but haze (white turbidity) is deteriorated.

When the ratio of the organic solvent having a solubility parameter (SP value) of 18.5 to 21 (MPa) ^1/2 with respect to the coating liquid is 20% or less, the adhesion / interference fringe deteriorates and is 45% or more. And haze deteriorate.

《Hard coat layer》
The functional film of the present invention has a hard coat layer on the surface of a cellulose ester film.

  The functional film preferably has a pencil hardness of H to 8H. Most preferably, it is 2H-6H. The pencil hardness is evaluated by pencil hardness evaluation specified by JIS K 5400 using a test pencil specified by JIS S 6006 after the prepared hard coat film is conditioned at a temperature of 25 ° C. and a relative humidity of 60% for 2 hours. It is the value measured according to the method.

(Polyfunctional acrylate)
In general, an actinic ray curable resin such as ultraviolet rays is used as the hard coat layer composition. In the present invention, it is preferable to contain a polyfunctional acrylate as such an actinic ray curable resin. The polyfunctional acrylate is preferably selected from the group consisting of pentaerythritol polyfunctional acrylate, dipentaerythritol polyfunctional acrylate, pentaerythritol polyfunctional methacrylate, and dipentaerythritol polyfunctional methacrylate. Here, the polyfunctional acrylate is a compound having two or more acryloyloxy groups and / or methacryloyloxy groups in the molecule.

  Examples of the polyfunctional acrylate monomer include ethylene glycol diacrylate, diethylene glycol diacrylate, 1,6-hexanediol diacrylate, neopentyl glycol diacrylate, trimethylolpropane triacrylate, trimethylolethane triacrylate, and tetramethylolmethane triacrylate. , Tetramethylolmethane tetraacrylate, pentaglycerol triacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, glycerol triacrylate, dipentaerythritol triacrylate, dipentaerythritol tetraacrylate, dipentaerythritol pentaacrylate, dipentaerythritol Ritolol hexaacrylate, tris (acryloyloxyethyl) isocyanurate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, trimethylolpropane trimethacrylate, trimethylolethane trimethacrylate, Tetramethylol methane trimethacrylate, tetramethylol methane tetramethacrylate, pentaglycerol trimethacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, glycerol trimethacrylate, dipentaerythritol trimethacrylate, dipentaerythritol tetramethacrylate Acrylate, dipentaerythritol penta methacrylate, dipentaerythritol hexa methacrylate, isobornyl acrylate and the like preferably. These compounds are used alone or in combination of two or more. Moreover, oligomers, such as a dimer and a trimer of the said monomer, may be sufficient.

  In order to accelerate the curing of the actinic ray curable resin, the photopolymerization initiator is preferably contained in a mass ratio of 20: 100 to 0.01: 100 with respect to the polyfunctional acrylate.

  Examples of the photopolymerization initiator include acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof, but are not particularly limited thereto.

  In addition to the photopolymerization initiator, a photosensitizer may be used. Examples of the photosensitizer include, but are not limited to, n-butylamine, triethylamine, triethanolamine, tri-n-butylphosphine and the like and derivatives thereof.

In the hard coat layer according to the present invention, a binder such as a known thermoplastic resin, thermosetting resin, or hydrophilic resin such as gelatin can be mixed with the actinic ray curable resin. These resins preferably have a polar group in the molecule. Examples of the polar _{group, -COOM, -OH, -NR 2,} -NR 3 X, -SO 3 M, -OSO 3 M, -PO 3 M 2, -OPO 3 M ( wherein, M represents a hydrogen atom, an alkali A metal or an ammonium group, X represents an acid forming an amine salt, R represents a hydrogen atom or an alkyl group).

  Commercially available actinic radiation curable resins that can be used in the present invention include ADEKA OPTMER KR / BY series: KR-400, KR-410, KR-550, KR-566, KR-567, BY-320B (Asahi) Manufactured by Denka Co., Ltd.); Koei Hard A-101-KK, A-101-WS, C-302, C-401-N, C-501, M-101, M-102, T-102, D-102 NS-101, FT-102Q8, MAG-1-P20, AG-106, M-101-C (manufactured by Guangei Chemical Co., Ltd.); Seika Beam PHC2210 (S), PHC X-9 (K-3), PHC2213 , DP-10, DP-20, DP-30, P1000, P1100, P1200, P1300, P1400, P1500, P1600, SCR900 (Daiichi Seikagaku Corporation KRM7033, KRM7039, KRM7130, KRM7131, UVECRYL29201, UVECRYL29202 (manufactured by Daicel UC Corporation); RC-5015, RC-5016, RC-5020, RC-5031, RC-5100, RC-5102, RC -5120, RC-5122, RC-5152, RC-5171, RC-5180, RC-5181 (Dainippon Ink Chemical Co., Ltd.); 340 clear (manufactured by China Paint Co., Ltd.); Sunrad H-601, RC-750, RC-700, RC-600, RC-500, RC-611, RC-612 (manufactured by Sanyo Chemical Industries); SP -1509, SP-1507 (manufactured by Showa Polymer Co., Ltd.); RCC-15C (manufactured by Grace Japan Co., Ltd.), Aronix M-6100, M-8030, M-8060 (manufactured by Toagosei Co., Ltd.); B420 (manufactured by Shin-Nakamura Chemical Co., Ltd.) or the like can be appropriately selected and used.

  Further, the hard coat layer may contain fine particles of an inorganic compound or an organic compound in order to adjust the scratch resistance, slipperiness and refractive index.

  Examples of inorganic fine particles used in the hard coat layer include silicon oxide, titanium oxide, aluminum oxide, tin oxide, indium oxide, ITO, zinc oxide, zirconium oxide, magnesium oxide, calcium carbonate, calcium carbonate, talc, clay, and calcined kaolin. And calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate and calcium phosphate. In particular, silicon oxide, titanium oxide, aluminum oxide, zirconium oxide, magnesium oxide and the like are preferably used.

  Organic particles include polymethacrylic acid methyl acrylate resin powder, acrylic styrene resin powder, polymethyl methacrylate resin powder, silicone resin powder, polystyrene resin powder, polycarbonate resin powder, benzoguanamine resin powder, and melamine resin powder. An ultraviolet curable resin composition such as polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, or polyfluoroethylene resin powder can be added. Particularly preferred are cross-linked polystyrene particles (for example, SX-130H, SX-200H, SX-350H, manufactured by Soken Chemical), polymethyl methacrylate-based particles (for example, MX150, MX300, manufactured by Soken Chemical), and fluorine-containing acrylic resin fine particles. . Examples of the fluorine-containing acrylic resin fine particles include commercial products such as FS-701 manufactured by Nippon Paint. Examples of the acrylic particles include Nippon Paint: S-4000, and examples of the acrylic-styrene particles include Nippon Paint: S-1200, MG-251.

  The average particle diameter of these fine particle powders is preferably 0.01 to 5 μm, more preferably 0.1 to 5.0 μm, and particularly preferably 0.1 to 4.0 μm. Moreover, it is preferable to contain 2 or more types of microparticles | fine-particles from which a particle size differs. The proportion of the ultraviolet curable resin composition and the fine particles is desirably blended so as to be 0.1 to 30 parts by mass with respect to 100 parts by mass of the resin composition.

  In order to increase the heat resistance of the hard coat layer, an antioxidant that does not inhibit the photocuring reaction can be selected and used. Examples include hindered phenol derivatives, thiopropionic acid derivatives, phosphite derivatives, and the like. Specifically, for example, 4,4′-thiobis (6-tert-3-methylphenol), 4,4′-butylidenebis (6-tert-butyl-3-methylphenol), 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate, 2,4,6-tris (3,5-di-tert-butyl-4-hydroxybenzyl) mesitylene, di-octadecyl-4- Examples thereof include hydroxy-3,5-di-tert-butylbenzyl phosphate.

  Further, the hard coat layer preferably contains a silicone surfactant or a polyoxyether compound. As the silicone surfactant, polyether-modified silicone is preferable. Specifically, BYK-UV3500, BYK-UV3510, BYK-333, BYK-331, BYK-337 (manufactured by BYK-Chemical Japan), TSF4440, TSF4445, TSF4446, TSF4452, TSF4460 (manufactured by GE Toshiba Silicone), KF-351, KF-351A, KF-352, KF-353, KF-354, KF-355, KF-615, KF-618, KF-945, KF- 6004 (polyether-modified silicone oil; manufactured by Shin-Etsu Chemical Co., Ltd.), and the like, but are not limited thereto.

  Of the polyoxyether compounds, the polyoxyethylene oleyl ether compound is preferable, and is generally a compound represented by the general formula (α).

Formula (α) C ₁₈ H ₃₅ —O (C ₂ H ₄ O) nH
In the formula, n represents 2 to 40.

  The average addition number (n) of ethylene oxide with respect to the oleyl part is 2 to 40, preferably 2 to 10, more preferably 2 to 9, and further preferably 2 to 8. The compound of the general formula (α) can be obtained by reacting ethylene oxide with oleyl alcohol.

  Specific products include Emulgen 404 (polyoxyethylene (4) oleyl ether), Emulgen 408 (polyoxyethylene (8) oleyl ether), Emulgen 409P (polyoxyethylene (9) oleyl ether), Emulgen 420 (polyoxy) Ethylene (13) oleyl ether), Emulgen 430 (polyoxyethylene (30) oleyl ether) or more, Kao Corporation, NOFBLEEAO-9905 (polyoxyethylene (5) oleyl ether) manufactured by NOF Corporation.

  The numbers in parentheses () represent the number n. Nonionic polyoxyether compounds may be used alone or in combination of two or more.

  These components are preferably added in the range of 0.01 to 3% by mass with respect to the solid component in the coating solution.

  Further, the hard coat layer may contain a fluorine-siloxane graft polymer.

  The fluorine-siloxane graft polymer refers to a copolymer polymer obtained by grafting polysiloxane containing siloxane and / or organosiloxane alone and / or organopolysiloxane to at least a fluorine-based resin. Examples of commercially available products include ZX-022H, ZX-007C, ZX-049, and ZX-047-D manufactured by Fuji Kasei Kogyo Co., Ltd. These compounds may be used as a mixture. Fluorine-siloxane graft polymer should be used in a coating solution that has a mass ratio of actinic ray curable resin to fluorine-siloxane graft polymer: energy-active radiation curable resin = 0.05: 100 to 5.00: 100. To preferred.

  The hard coat layer coating solution contains an organic solvent used in the functional layer coating solution.

  The hard coat layer may have a multilayer structure of two or more layers. One of the layers may be a so-called conductive layer containing, for example, conductive fine particles, a π-conjugated conductive polymer, or an ionic polymer. Examples of the π-conjugated conductive polymer include polythiophene, poly (3-methylthiophene), poly (3-ethylthiophene), poly (3-propylthiophene), poly (3-butylthiophene), and poly (3-hexylthiophene). , Poly (3-octylthiophene), poly (3-decylthiophene), poly (3-dodecylthiophene), poly (3-bromothiophene), poly (3-chlorothiophene), poly (3-cyanothiophene), poly (3-phenylthiophene), poly (3,4-dimethylthiophene), poly (3,4-dibutylthiophene), poly (3-hydroxythiophene), poly (3-methoxythiophene), poly (3-ethoxythiophene) , Poly (3-butoxythiophene), poly (3-hexyloxythiophene), poly (3 Octyloxythiophene), poly (3-decyloxythiophene), poly (3-dodecyloxythiophene), poly (3,4-dihydroxythiophene), poly (3,4-dimethoxythiophene), poly (3,4-di Ethoxythiophene), poly (3,4-dipropoxythiophene), poly (3,4-dibutoxythiophene), poly (3,4-dihexyloxythiophene), poly (3,4-dioctyloxythiophene), poly ( 3,4-didecyloxythiophene), poly (3,4-didodecyloxythiophene), poly (3,4-ethylenedioxythiophene), poly (3,4-propylenedioxythiophene), poly (3,4 4-butenedioxythiophene), poly (3-methyl-4-methoxythiophene), poly (3-methyl-4 -Ethoxythiophene), poly (3-carboxythiophene), poly (3-methyl-4-carboxythiophene), poly (3-methyl-4-carboxyethylthiophene), poly (3-methyl-4-carboxybutylthiophene) , Polypyrrole, poly (N-methylpyrrole), poly (3-methylpyrrole), poly (3-ethylpyrrole), poly (3-N-propylpyrrole), poly (3-butylpyrrole), poly (3-octyl) Pyrrole), poly (3-decylpyrrole), poly (3-dodecylpyrrole), poly (3,4-dimethylpyrrole), poly (3,4-dibutylpyrrole), poly (3-carboxypyrrole), poly (3 -Methyl-4-carboxypyrrole), poly (3-methyl-4-carboxyethylpyrrole), poly (3-methyl 4-carboxybutylpyrrole), poly (3-hydroxypyrrole), poly (3-methoxypyrrole), poly (3-ethoxypyrrole), poly (3-butoxypyrrole), poly (3-hexyloxypyrrole), poly ( 3-methyl-4-hexyloxypyrrole), polyaniline, poly (2-methylaniline), poly (3-isobutylaniline), poly (2-anilinesulfonic acid), poly (3-anilinesulfonic acid) and the like. . Each of these may be used alone or two types of copolymers can be suitably used.

  Further, the ionic polymer may contain a color tone adjusting agent (dye or pigment) having a color tone adjusting function as a color correction filter for various display elements, or may contain an electromagnetic wave blocking agent or an infrared absorber. It is preferable to have each function.

  As a coating method of the hard coat layer coating solution, it can be applied by a known method such as a gravure coater, a dip coater, a reverse coater, a wire bar coater, a die coater, or an ink jet method.

  The coating amount is suitably 0.1 to 40 μm, preferably 0.5 to 30 μm, as the wet film thickness. Moreover, as a dry film thickness, it is an average film thickness of 0.1-30 micrometers, Preferably it is 1-20 micrometers.

  The hard coat layer is preferably irradiated with ultraviolet rays after coating and drying, and the irradiation time for obtaining the necessary amount of active light irradiation is preferably about 0.1 second to 1 minute, and the curing efficiency of the ultraviolet curable resin Or from the viewpoint of work efficiency, 0.1 to 10 seconds is more preferable.

Moreover, it is preferable that the illuminance of these actinic ray irradiation parts is 0.05-0.2 W / m < ² >.

  The hard coat layer has a center line average roughness (Ra) defined by JIS B 0601 of 0.001 to 0.1 μm, or a fine hard coat layer and Ra is adjusted to 0.1 to 1 μm. An antiglare hard coat layer may also be used. The center line average roughness (Ra) is preferably measured by an optical interference type surface roughness measuring instrument, and can be measured, for example, using a non-contact surface fine shape measuring device WYKO NT-2000 manufactured by WYKO.

<Antireflection layer>
An antireflection layer is provided on the hard coat layer, and can be used as a hard coat film having an external light antireflection function (hereinafter also referred to as an antireflection film).

  The antireflection layer is preferably laminated in consideration of the refractive index, the film thickness, the number of layers, the layer order, and the like so that the reflectance is reduced by optical interference. The antireflection layer is preferably composed of a low refractive index layer having a refractive index lower than that of the support, or a combination of a high refractive index layer having a refractive index higher than that of the support and a low refractive index layer. Particularly preferably, it is an antireflection layer composed of three or more refractive index layers, and three layers having different refractive indexes from the support side are divided into medium refractive index layers (high refractive index layers having a higher refractive index than the support). Are preferably laminated in the order of a layer having a lower refractive index) / a high refractive index layer / a low refractive index layer. Alternatively, an antireflection layer having a layer structure of four or more layers in which two or more high refractive index layers and two or more low refractive index layers are alternately laminated is also preferably used.

  Although the following structures can be considered as a layer structure of the film of this invention, it is not limited to this.

Film substrate / Hard coat layer Film substrate / Hard coat layer / Medium refractive index layer / Low refractive index layer Film substrate / Hard coat layer / Medium refractive index layer / High refractive index layer / Low refractive index layer Film substrate / Hard coat layer / Low refractive index layer Film substrate / Hard coat layer / High refractive index layer (conductive layer) / Low refractive index layer Film substrate / Hard coat layer / Anti-glare layer Film substrate / Hard coat layer / Antiglare layer / Low refractive index layer [Low refractive index layer]
The low refractive index layer used in the present invention preferably contains silica-based fine particles, and the refractive index thereof is lower than the refractive index of the film substrate as a support, and is 1.30 at 23 ° C. and a wavelength of 550 nm. A range of ˜1.45 is preferred.

  The film thickness of the low refractive index layer is preferably 5 nm to 0.5 μm, more preferably 10 nm to 0.3 μm, and most preferably 30 nm to 0.2 μm.

  The composition for forming a low refractive index layer used in the present invention preferably contains at least one kind of particles having an outer shell layer and porous or hollow inside as silica-based fine particles. In particular, the particles having the outer shell layer and having a porous or hollow interior are preferably hollow silica-based fine particles.

  The composition for forming a low refractive index layer may contain an organosilicon compound represented by the following general formula (OSi-1) or a hydrolyzate thereof, or a polycondensate thereof.

General formula (OSi-1): Si (OR) ₄
In the organic silicon compound represented by the general formula, R represents an alkyl group having 1 to 4 carbon atoms. Specifically, tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane and the like are preferably used.

  In addition, a silane coupling agent, a curing agent, a surfactant and the like may be added as necessary.

(Hollow silica fine particles)
The hollow silica-based fine particles are (I) composite particles comprising porous particles and a coating layer provided on the surface of the porous particles, or (II) having cavities inside, and the contents are solvent, gas or porous It is a hollow particle filled with a porous material. Note that the low refractive index layer only needs to contain either (I) composite particles or (II) hollow particles, or both.

  Note that the cavity particles are particles having a cavity inside, and the cavity is covered with a coating layer (also referred to as a particle wall). The cavity is filled with contents such as a solvent, a gas, or a porous material used at the time of preparation. It is desirable that the average particle size of such hollow fine particles is in the range of 5 to 300 nm, preferably 10 to 200 nm. The average particle diameter of the hollow fine particles used is desirably 3/2 to 1/10, preferably 2/3 to 1/10, of the average film thickness of the low refractive index layer to be formed. These hollow fine particles are preferably used in a state of being dispersed in an appropriate medium in order to form a low refractive index layer. As the dispersion medium, water, alcohol (for example, methanol, ethanol, isopropyl alcohol) and ketone (for example, methyl ethyl ketone, methyl isobutyl ketone), ketone alcohol (for example, diacetone alcohol), or a mixed solvent containing these is preferable.

  The thickness of the coating layer of the composite particles or the thickness of the particle walls of the hollow particles is desirably in the range of 1 to 20 nm, preferably 2 to 15 nm. In the case of composite particles, if the thickness of the coating layer is less than 1 nm, the particles may not be completely covered, and it is easy to use a silicate monomer or oligomer having a low polymerization degree, which is a coating liquid component described later. In some cases, the refractive index of the particles is increased by entering the voids inside the composite particles, and the effect of low refractive index may not be sufficiently obtained. When the thickness of the coating layer exceeds 20 nm, the silicic acid monomer and oligomer do not enter the inside, but the porosity (pore volume) of the composite particles is lowered and the effect of low refractive index is sufficiently obtained. It may not be possible. In the case of hollow particles, if the particle wall thickness is less than 1 nm, the particle shape may not be maintained, and even if the thickness exceeds 20 nm, the effect of low refractive index may not be sufficiently exhibited. .

The coating layer of the composite particles or the particle wall of the hollow particles is preferably composed mainly of silica. In addition, components other than silica may be contained. Specifically, Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , CeO ₂ , P ₂ O ₃ , Sb ₂ O ₃ , MoO ₃ , ZnO ₂ , WO _{3 and the} like. Examples of the porous particles constituting the composite particles include those made of silica, those made of silica and an inorganic compound other than silica, and those made of CaF ₂ , NaF, NaAlF ₆ , MgF, and the like. Of these, porous particles made of a composite oxide of silica and an inorganic compound other than silica are particularly suitable. Examples of inorganic compounds other than silica include Al ₂ O ₃ , B ₂ O ₃ , TiO ₂ , ZrO ₂ , SnO ₂ , CeO ₂ , P ₂ O ₃ , Sb ₂ O ₃ , MoO ₃ , ZnO ₂ , WO _{3 and the} like. 1 type or 2 types or more can be mentioned. In such porous particles, the molar ratio MO _X / SiO ₂ when the silica is expressed by SiO ₂ and the inorganic compound other than silica is expressed in terms of oxide (MO _X ) is 0.0001 to 1.0, Preferably it is in the range of 0.001 to 0.3. It is difficult to obtain a porous particle having a molar ratio MO _X / SiO ₂ of less than 0.0001. Even if it is obtained, particles having a small pore volume and a low refractive index cannot be obtained. In addition, when the molar ratio MO _X / SiO _{2 of} the porous particles exceeds 1.0, the ratio of silica decreases, so that the pore volume increases and it is difficult to obtain a material having a lower refractive index. is there.

  The pore volume of such porous particles is desirably in the range of 0.1 to 1.5 ml / g, preferably 0.2 to 1.5 ml / g. If the pore volume is less than 0.1 ml / g, particles having a sufficiently reduced refractive index cannot be obtained. If the pore volume exceeds 1.5 ml / g, the strength of the fine particles is lowered, and the strength of the resulting coating may be lowered. is there.

  In addition, the pore volume of such porous particles can be determined by a mercury intrusion method. Examples of the contents of the hollow particles include a solvent, a gas, and a porous substance used at the time of preparing the particles. The solvent may contain an unreacted particle precursor used when preparing the hollow particles, the catalyst used, and the like. Moreover, what consists of the compound illustrated by the said porous particle as a porous substance is mentioned. These contents may be composed of a single component or may be a mixture of a plurality of components.

  As a method for producing such hollow fine particles, for example, the method for preparing composite oxide colloidal particles disclosed in paragraphs [0010] to [0033] of JP-A-7-133105 is suitably employed. The refractive index of the inorganic fine particles obtained by this method is as low as less than 1.42. Such inorganic fine particles are presumed to have a low refractive index because the porosity inside the porous particles is maintained or the inside is hollow. As the hollow silica-based fine particles, those commercially available from Catalyst Kasei Co., Ltd. can be preferably used.

  The content of the hollow silica-based fine particles having an outer shell layer and porous or hollow inside is preferably 10 to 50% by mass. In order to obtain the effect of a low refractive index, the content is preferably 15% by mass or more, and when it exceeds 50% by mass, the binder component is decreased and the film strength becomes insufficient. Most preferably, it is 20-50 mass%.

  As a method of adding to the low refractive index layer, for example, a solution obtained by adding a small amount of alkali or acid as a catalyst to a mixed solution of the tetraalkoxysilane, pure water, and alcohol is added to the dispersion of the hollow silica fine particles. The silicic acid polymer produced by hydrolyzing tetraalkoxysilane is deposited on the surface of the hollow silica fine particles. At this time, tetraalkoxysilane, alcohol, and catalyst may be simultaneously added to the dispersion. As the alkali catalyst, ammonia, an alkali metal hydroxide, or an amine can be used. As the acid catalyst, various inorganic acids and organic acids can be used.

  In the present invention, the low refractive index layer may contain a fluorine-substituted alkyl group-containing silane compound represented by the following general formula (OSi-2).

  The fluorine-substituted alkyl group-containing silane compound represented by the general formula (OSi-2) will be described.

In the formula, R ^{1 to} R ⁶ are alkyl groups having 1 to 16 carbon atoms, preferably 1 to 4 carbon atoms, halogenated alkyl groups having 1 to 6 carbon atoms, preferably 1 to 4 carbon atoms, 6 to 12 carbon atoms, preferably 6 carbon atoms. 10 to 10 aryl groups, 7 to 14 carbon atoms, preferably 7 to 12 alkylaryl groups, arylalkyl groups, 2 to 8 carbon atoms, preferably 2 to 6 alkenyl groups, or 1 to 6 carbon atoms, preferably 1 to 3 alkoxy groups, a hydrogen atom or a halogen atom.

Rf represents-(CaHbFc)-, a is an integer of 1 to 12, b + c is 2a, b is an integer of 0 to 24, and c is an integer of 0 to 24. Such Rf is preferably a group having a fluoroalkylene group and an alkylene group. Specifically, as such a fluorine-containing silicone compound, (MeO) ₃ SiC ₂ H ₄ C ₂ F ₄ C ₂ H ₄ Si (MeO) ₃ , (MeO) ₃ SiC ₂ H ₄ C ₄ F ₈ C ₂ H ₄ Si (MeO) ₃ , (MeO) ₃ SiC ₂ H ₄ C ₆ F ₁₂ C ₂ H ₄ Si (MeO) ₃ , (H ₅ C ₂ O) ₃ SiC ₂ H ₄ C ₄ F ₈ C ₂ H Examples include methoxydisilane compounds represented by ₄ Si (OC ₂ H ₅ ) ₃ , (H ₅ C ₂ O) ₃ SiC ₂ H ₄ C ₆ F ₁₂ C ₂ H ₄ Si (OC ₂ H ₅ ) ₃ , and the like.

  If the fluorine-containing alkyl group-containing silane compound is included as a binder, the transparent film itself is hydrophobic, so the transparent film is not sufficiently densified and is porous or cracked. Even if it has a void or a void, entry into the transparent film by chemicals such as moisture, acid and alkali is suppressed. Furthermore, fine particles such as metals contained in the conductive layer which is the substrate surface or the lower layer do not react with chemicals such as moisture, acid and alkali. For this reason, such a transparent film has excellent chemical resistance.

  In addition, when a fluorine-substituted alkyl group-containing silane compound is included as a binder, not only the hydrophobic property but also the slipperiness (low contact resistance) is obtained, and thus a transparent film having excellent scratch strength can be obtained. Can do. Further, when the binder contains a fluorine-substituted alkyl group-containing silane compound having such a structural unit, when the conductive layer is formed in the lower layer, the shrinkage rate of the binder is equivalent to that of the conductive layer. Therefore, it is possible to form a transparent film having excellent adhesion to the conductive layer. Furthermore, when the transparent film is heat-treated, the conductive layer is not peeled off due to the difference in shrinkage rate, and a portion having no electrical contact is not generated in the transparent conductive layer. For this reason, sufficient electroconductivity can be maintained as a whole film.

  A transparent film containing a fluorine-substituted alkyl group-containing silane compound and hollow silica-based fine particles having the outer shell layer and being porous or hollow inside has high scratch strength and is evaluated by eraser strength or nail strength. The film strength is high, the pencil hardness is high, and a transparent film excellent in strength can be formed.

  The low refractive index layer used in the present invention may contain a silane coupling agent. Silane coupling agents include methyltrimethoxysilane, methyltriethoxysilane, methyltrimethoxyethoxysilane, methyltriacetoxysilane, methyltributoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, vinyltrimethoxysilane, vinyltrimethoxysilane. Ethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltriacetoxysilane, γ-chloropropyltrimethoxysilane, γ-chloropropyltriethoxysilane, γ-chloropropyltri Acetoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, γ-glycidyloxypropyltrimethoxysilane, γ-glycidyloxypropyltri Ethoxysilane, γ- (β-glycidyloxyethoxy) propyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltriethoxysilane, γ- Acryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropyltriethoxysilane, N- Examples include β- (aminoethyl) -γ-aminopropyltrimethoxysilane and β-cyanoethyltriethoxysilane.

  Examples of silane coupling agents having a disubstituted alkyl group with respect to silicon include dimethyldimethoxysilane, phenylmethyldimethoxysilane, dimethyldiethoxysilane, phenylmethyldiethoxysilane, and γ-glycidyloxypropylmethyldiethoxysilane. Γ-glycidyloxypropylmethyldimethoxysilane, γ-glycidyloxypropylphenyldiethoxysilane, γ-chloropropylmethyldiethoxysilane, dimethyldiacetoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldi Ethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, γ-methacryloyloxypropylmethyldiethoxysilane, γ-mercaptopropylmethyldimeth Shishiran, .gamma.-mercaptopropyl methyl diethoxy silane, .gamma.-aminopropyl methyl dimethoxy silane, .gamma.-aminopropyl methyl diethoxy silane, methyl vinyl dimethoxy silane, and methyl vinyl diethoxy silane.

  Among these, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltriacetoxysilane, vinyltrimethoxyethoxysilane, γ-acryloyloxypropyltrimethoxysilane and γ-methacryloyloxypropyltrimethoxysilane having a double bond in the molecule. Γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane, and γ-methacryloyloxypropylmethyldiethoxy having a disubstituted alkyl group with respect to silicon Silane, methylvinyldimethoxysilane and methylvinyldiethoxysilane are preferred, and γ-acryloyloxypropyltrimethoxysilane and γ-methacryloyloxyp Particularly preferred are propyltrimethoxysilane, γ-acryloyloxypropylmethyldimethoxysilane, γ-acryloyloxypropylmethyldiethoxysilane, γ-methacryloyloxypropylmethyldimethoxysilane and γ-methacryloyloxypropylmethyldiethoxysilane.

  Two or more coupling agents may be used in combination. In addition to the silane coupling agents shown above, other silane coupling agents may be used. Other silane coupling agents include alkyl esters of orthosilicate (eg, methyl orthosilicate, ethyl orthosilicate, n-propyl orthosilicate, i-propyl orthosilicate, n-butyl orthosilicate, sec-butyl orthosilicate, orthosilicate). Acid t-butyl) and its hydrolyzate.

The low refractive index layer may contain a silicon compound represented by CF ₃ (CF ₂ ) nCH ₂ CH ₂ Si (OR ₁ ) ₃ . (In the formula, R1 represents an alkyl group having 1 to 5 carbon atoms, and n represents an integer of 0 to 12.) Specific examples of the compound include trifluoropropyltrimethoxysilane and trifluoropropyl. Examples include triethoxysilane, tridecafluorooctyltrimethoxysilane, tridecafluorooctyltriethoxysilane, heptadecafluorodecyltrimethoxysilane, heptadecafluorodecyltriethoxysilane, and these are used alone or in combination of two or more. Can be used.

It may also contain _{H 2 NCONH (CH) mSi (} OR2) silicon compound in the terminal position represented by ₃ having a ureido group (H ₂ NCONH-). (In the formula, R2 represents an alkyl group having 1 to 5 carbon atoms, and m represents an integer of 1 to 5.) Specific compounds include γ-ureidopropyltrimethoxysilane and γ-ureido. Examples thereof include propyltriethoxysilane and γ-ureidopropyltripropoxysilane. Among these, γ-ureidopropyltrimethoxysilane, γ-ureidopropyltriethoxysilane, and the like are particularly preferable.

  In addition, the low refractive index layer can use, for example, polyvinyl alcohol, polyoxyethylene, polymethyl methacrylate, polymethyl acrylate, fluoroacrylate, diacetyl cellulose, triacetyl cellulose, nitrocellulose, polyester, alkyd resin, etc. as a binder. .

  In addition, the low refractive index layer includes, for example, polyvinyl alcohol, polyoxyethylene, polymethyl methacrylate, polymethyl acrylate, fluoroacrylate, diacetyl cellulose, triacetyl cellulose, nitrocellulose, polyester, and alkyd resin as a binder.

  The low refractive index layer preferably contains 5 to 80% by mass of binder as a whole. The binder has a function of adhering the hollow silica-based fine particles and maintaining the structure of the low refractive index layer including voids. The usage-amount of a binder is suitably adjusted so that the intensity | strength of a low refractive index layer can be maintained, without filling a space | gap.

(solvent)
The low refractive index layer used in the present invention preferably contains an organic solvent. Specific examples of organic solvents include alcohols (eg, methanol, ethanol, isopropanol, butanol, benzyl alcohol), ketones (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone), esters (eg, methyl acetate, ethyl acetate). , Propyl acetate, butyl acetate, methyl formate, ethyl formate, propyl formate, butyl formate), aliphatic hydrocarbons (eg, hexane, cyclohexane), halogenated hydrocarbons (eg, methylene chloride, chloroform, carbon tetrachloride), aromatic Group hydrocarbon (eg, benzene, toluene, xylene), amide (eg, dimethylformamide, dimethylacetamide, n-methylpyrrolidone), ether (eg, diethyl ether, dioxane, tetrahydrofuran), ether alcohol (eg, 1-methoxy-2-propanol). Of these, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and butanol are particularly preferable.

  The solid content concentration in the low refractive index layer coating composition is preferably 1 to 4% by mass. By making the solid content concentration 4% by mass or less, coating unevenness is less likely to occur, and the content is 1% by mass or more. By doing so, the drying load is reduced.

(High refractive index layer)
In the present invention, it is preferable that the antireflective layer has the following high refractive index layer in addition to the above-described low refractive index layer.

  The high refractive index layer used in the present invention preferably contains metal oxide fine particles. The kind of metal oxide fine particles is not particularly limited, and Ti, Zr, Sn, Sb, Cu, Fe, Mn, Pb, Cd, As, Cr, Hg, Zn, Al, Mg, Si, P and S A metal oxide having at least one element selected from the group consisting of Al, In, Sn, Sb, Nb, a halogen element, Ta and the like is doped with a minute amount of atoms. May be. A mixture of these may also be used. In the present invention, at least one metal oxide fine particle selected from among zirconium oxide, antimony oxide, tin oxide, zinc oxide, indium-tin oxide (ITO), antimony-doped tin oxide (ATO), and zinc antimonate is used. It is particularly preferable to use it as the main component. In particular, it is preferable to contain zinc antimonate particles.

  The average particle diameter of the primary particles of these metal oxide fine particles is in the range of 10 nm to 200 nm, particularly preferably 10 to 150 nm. The average particle diameter of the metal oxide fine particles can be measured from an electron micrograph taken with a scanning electron microscope (SEM) or the like. You may measure by the particle size distribution meter etc. which utilize a dynamic light scattering method, a static light scattering method, etc. If the particle size is too small, aggregation tends to occur and the dispersibility deteriorates. If the particle size is too large, the haze is remarkably increased. The shape of the metal oxide fine particles is preferably a rice grain shape, a spherical shape, a cubic shape, a spindle shape, a needle shape, or an indefinite shape.

  Specifically, the refractive index of the high refractive index layer is higher than the refractive index of the film as the support, and is preferably in the range of 1.5 to 2.2 when measured at 23 ° C. and a wavelength of 550 nm. The means for adjusting the refractive index of the high refractive index layer is that the kind and addition amount of the metal oxide fine particles are dominant, so that the refractive index of the metal oxide fine particles is preferably 1.80 to 2.60, More preferably, it is 1.85 to 2.50.

  The metal oxide fine particles may be surface-treated with an organic compound. By modifying the surface of the metal oxide fine particles with an organic compound, the dispersion stability in an organic solvent is improved, the dispersion particle size can be easily controlled, and aggregation and sedimentation over time can be suppressed. . For this reason, the surface modification amount with a preferable organic compound is 0.1 mass%-5 mass% with respect to metal oxide particle, More preferably, it is 0.5 mass%-3 mass%. Examples of the organic compound used for the surface treatment include polyols, alkanolamines, stearic acid, silane coupling agents, and titanate coupling agents. Of these, silane coupling agents are preferred. Two or more kinds of surface treatments may be combined.

  The thickness of the high refractive index layer containing the metal oxide fine particles is preferably 5 nm to 1 μm, more preferably 10 nm to 0.2 μm, and most preferably 30 nm to 0.1 μm.

  The ratio of the metal oxide fine particles to be used and a binder such as an actinic ray curable resin to be described later varies depending on the kind of metal oxide fine particles, the particle size, etc. The latter one is preferable.

  The amount of the metal oxide fine particles used in the present invention is preferably 5% by mass to 85% by mass in the high refractive index layer, more preferably 10% by mass to 80% by mass, and most preferably 20% to 75% by mass. preferable. If the amount used is small, the desired refractive index and the effect of the present invention cannot be obtained, and if it is too large, the film strength deteriorates.

  The metal oxide fine particles are supplied to a coating solution for forming a high refractive index layer in a dispersion state dispersed in a medium. As a dispersion medium for metal oxide particles, it is preferable to use a liquid having a boiling point of 60 to 170 ° C. Specific examples of the dispersion solvent include water, alcohol (eg, methanol, ethanol, isopropanol, butanol, benzyl alcohol), ketone (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone), ketone alcohol (eg, diacetone alcohol). , Esters (eg, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl formate, ethyl formate, propyl formate, butyl formate), aliphatic hydrocarbons (eg, hexane, cyclohexane), halogenated hydrocarbons (eg, methylene) Chloride, chloroform, carbon tetrachloride), aromatic hydrocarbons (eg, benzene, toluene, xylene), amides (eg, dimethylformamide, dimethylacetamide, n-methylpyrrolidone), ethers (eg, diethyl ether, dioxane, Tiger hydrofuran), ether alcohols (e.g., 1-methoxy-2-propanol), propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate. Of these, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and butanol are particularly preferable.

  The metal oxide fine particles can be dispersed in the medium using a disperser. Examples of the disperser include a sand grinder mill (eg, a bead mill with pins), a high-speed impeller mill, a pebble mill, a roller mill, an attritor, and a colloid mill. A sand grinder mill and a high-speed impeller mill are particularly preferred. Further, preliminary dispersion processing may be performed. Examples of the disperser used for the preliminary dispersion treatment include a ball mill, a three-roll mill, a kneader, and an extruder. It is also preferable to contain a dispersant.

  In the present invention, metal oxide fine particles having a core / shell structure may be further contained. One layer of the shell may be formed around the core, or a plurality of layers may be formed in order to further improve the light resistance. The core is preferably completely covered by the shell.

  For the core, titanium oxide (rutile type, anatase type, amorphous type, etc.), zirconium oxide, zinc oxide, cerium oxide, indium oxide doped with tin, tin oxide doped with antimony, etc. can be used. Titanium may be the main component.

  The shell is preferably formed of a metal oxide or sulfide containing an inorganic compound other than titanium oxide as a main component. For example, an inorganic compound mainly composed of silicon dioxide (silica), aluminum oxide (alumina) zirconium oxide, zinc oxide, tin oxide, antimony oxide, indium oxide, iron oxide, zinc sulfide, or the like is used. Of these, alumina, silica, and zirconia (zirconium oxide) are preferable. A mixture of these may also be used.

  The coating amount of the shell with respect to the core is 2 to 50% by mass as an average coating amount. Preferably it is 3-40 mass%, More preferably, it is 4-25 mass%. When the coating amount of the shell is large, the refractive index of the fine particles is lowered, and when the coating amount is too small, the light resistance is deteriorated. Two or more inorganic fine particles may be used in combination.

  The titanium oxide used as a core can use what was produced by the liquid phase method or the gaseous-phase method. As a method for forming the shell around the core, for example, U.S. Pat. No. 3,410,708, JP-B-58-47061, U.S. Pat. No. 2,885,366, and U.S. Pat. No. 1, British Patent No. 1,134,249, US Pat. No. 3,383,231, British Patent No. 2,629,953, No. 1,365,999, etc. Can do.

  The high refractive index layer or the low refractive index layer used in the present invention can contain a compound represented by the following general formula (CL1) or a chelate compound thereof, and can improve physical properties such as hardness. it can.

General formula (CL1) _An MB _xn
In the formula, M represents a metal atom, A represents a hydrolyzable functional group or a hydrocarbon group having a hydrolyzable functional group, and B represents an atomic group covalently or ionically bonded to the metal atom M. x represents the valence of the metal atom M, and n represents an integer of 2 or more and x or less.

  Examples of the hydrolyzable functional group A include halogens such as alkoxyl groups and chloro atoms, ester groups and amide groups. The metal compound belonging to the general formula (CL1) includes an alkoxide having two or more alkoxyl groups directly bonded to a metal atom, or a chelate compound thereof. Preferable metal compounds include titanium alkoxide, zirconium alkoxide, or chelate compounds thereof. Titanium alkoxide has a high reaction rate and a high refractive index and is easy to handle. However, since it has a photocatalytic action, its light resistance deteriorates when added in a large amount. Zirconium alkoxide has a high refractive index but tends to become cloudy, so care must be taken in dew point management during coating. Moreover, since titanium alkoxide has the effect of promoting the reaction of the ultraviolet curable resin and metal alkoxide, the physical properties of the coating film can be improved by adding a small amount.

  Examples of the titanium alkoxide include tetramethoxy titanium, tetraethoxy titanium, tetra-iso-propoxy titanium, tetra-n-propoxy titanium, tetra-n-butoxy titanium, tetra-sec-butoxy titanium, tetra-tert-butoxy titanium, and the like. Is mentioned.

  Examples of the zirconium alkoxide include tetramethoxy zirconium, tetraethoxy zirconium, tetra-iso-propoxy zirconium, tetra-n-propoxy zirconium, tetra-n-butoxy zirconium, tetra-sec-butoxy zirconium, tetra-tert-butoxy zirconium and the like. Is mentioned.

  Preferred chelating agents for coordination with free metal compounds to form chelate compounds include alkanolamines such as diethanolamine and triethanolamine, glycols such as ethylene glycol, diethylene glycol and propylene glycol, acetylacetone and acetoacetate Examples thereof include ethyl and the like having a molecular weight of 10,000 or less. By using these chelating agents, it is possible to form a chelate compound that is stable against water mixing and is excellent in the effect of reinforcing the coating film.

  The addition amount of the metal compound is preferably adjusted so that the content of the metal oxide derived from the metal compound contained in the high refractive index layer is 0.3 to 5% by mass. If it is less than 0.3% by mass, the scratch resistance is insufficient, and if it exceeds 5% by mass, the light resistance tends to deteriorate.

  The high refractive index layer used in the present invention preferably contains an actinic ray curable resin as a binder for the metal oxide fine particles in order to improve the film formability and physical properties of the coating film. As the actinic ray curable resin, a monomer or oligomer having two or more functional groups that cause a polymerization reaction directly by irradiation with actinic rays such as ultraviolet rays or electron beams or indirectly by the action of a photopolymerization initiator is used. be able to. In the present invention, a polyol acrylate, an epoxy acrylate, a urethane acrylate, a polyester acrylate or a mixture thereof is preferable. For example, the polyfunctional acrylate compound described in the hard coat layer is preferable.

  The addition amount of the actinic ray curable resin is preferably 15% by mass or more and less than 50% by mass in the solid content in the high refractive index composition.

  In order to accelerate the curing of the actinic radiation curable resin used in the present invention, the photopolymerization initiator and the acrylic compound having two or more polymerizable unsaturated bonds in the molecule are in a mass ratio of 3: 7 to 1: 9. It is preferable to contain.

  Specific examples of the photopolymerization initiator include acetophenone, benzophenone, hydroxybenzophenone, Michler's ketone, α-amyloxime ester, thioxanthone, and derivatives thereof, but are not particularly limited thereto.

  Examples of the organic solvent used for coating the high refractive index layer used in the present invention include alcohols (for example, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol, pentanol). , Hexanol, cyclohexanol, benzyl alcohol, etc.), polyhydric alcohols (eg, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, polypropylene glycol, butylene glycol, hexanediol, pentanediol, glycerin) , Hexanetriol, thiodiglycol, etc.), polyhydric alcohol ethers (for example, ethylene glycol mono Chill ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monomethyl ether, diethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monobutyl ether, ethylene glycol monomethyl ether acetate, triethylene glycol monomethyl ether, triethylene glycol Monoethyl ether, ethylene glycol monophenyl ether, propylene glycol monophenyl ether, etc.), amines (eg, ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylene) Lumorpholine, ethylenediamine, diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, pentamethyldiethylenetriamine, tetramethylpropylenediamine, etc.), amides (eg, formamide, N, N-dimethylformamide, N, N-dimethylacetamide) Etc.), heterocyclic rings (for example, 2-pyrrolidone, N-methyl-2-pyrrolidone, cyclohexyl pyrrolidone, 2-oxazolidone, 1,3-dimethyl-2-imidazolidinone, etc.), sulfoxides (for example, dimethyl sulfoxide, etc.) ), Sulfones (for example, sulfolane, etc.), urea, acetonitrile, acetone and the like, and alcohols, polyhydric alcohols, and polyhydric alcohol ethers are particularly preferable.

  The medium refractive index layer can be produced by changing the ratio of the binder and the metal particles with the composition of the high refractive index layer.

(Polarizer)
When using the functional film of this invention as a polarizing plate protective film, the preparation methods of a polarizing plate are not specifically limited, It can produce by a general method.

  The optical film of the present invention is preferably subjected to alkali saponification treatment, and the treated optical film is bonded to at least one surface of a polarizing film produced by immersing and stretching in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. .

  The optical film of the present invention may be used on the other surface, or another polarizing plate protective film may be used. With respect to the optical film of the present invention, a commercially available optical film can be used as the polarizing plate protective film used on the other surface.

  For example, as a commercially available optical film, KC8UX2M, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UCR-3, KC8UCR-4, KC8UY-HA, KC8UX-RHA (manufactured by Konica Minolta Opto Co., Ltd. is preferably used), etc. It is done.

  Alternatively, it is also preferable to use a polarizing plate protective film that also serves as an optical compensation film having an optical anisotropic layer formed by aligning liquid crystal compounds such as discotic liquid crystal, rod-shaped liquid crystal, and cholesteric liquid crystal. For example, the optically anisotropic layer can be formed by the method described in JP-A-2003-98348.

  By using in combination with the optical film of the present invention, a polarizing plate having excellent flatness and a stable viewing angle expansion effect can be obtained.

  Or you may use optical films, such as cyclic olefin resin other than an optical film, an acrylic resin, polyester, a polycarbonate, as a polarizing plate protective film of the other surface.

  Instead of the alkali treatment, polarizing plate processing may be performed by performing easy adhesion processing as described in JP-A-6-94915 and JP-A-6-118232.

  The polarizing film, which is the main component of the polarizing plate, is an element that transmits only light having a polarization plane in a certain direction. A typical polarizing film known at present is a polyvinyl alcohol polarizing film, which is a polyvinyl alcohol film. There are one in which iodine is dyed on a system film and one in which dichroic dye is dyed.

  As the polarizing film, a polyvinyl alcohol aqueous solution is formed and dyed by uniaxially stretching or dyed, or uniaxially stretched after dyeing, and then preferably subjected to a durability treatment with a boron compound.

  The thickness of the polarizing film is 5 to 40 μm, preferably 5 to 30 μm, and particularly preferably 5 to 20 μm.

  On the surface of the polarizing film, one side of the cellulose ester film of the present invention is bonded to form a polarizing plate. It is preferably bonded with an aqueous adhesive mainly composed of completely saponified polyvinyl alcohol or the like.

  Since the polarizing film is stretched in a uniaxial direction (usually the longitudinal direction), when the polarizing plate is placed in a high-temperature and high-humidity environment, the stretching direction (usually the longitudinal direction) shrinks, and the direction perpendicular to the stretching (usually the width direction) ) Will grow. As the thickness of the polarizing plate protective film becomes thinner, the expansion / contraction ratio of the polarizing plate increases, and in particular, the amount of contraction in the stretching direction of the polarizing film increases.

  Normally, the stretching direction of the polarizing film is bonded to the casting direction (MD direction) of the polarizing plate protective film. Therefore, when making the polarizing plate protective film thin, it is particularly important to suppress the stretching rate in the casting direction. It is. Since the optical film of the present invention is extremely excellent in dimensional stability, it is suitably used as such a polarizing plate protective film.

  That is, even in the durability test under the condition of 60 ° C. and 90% RH, the wavy irregularity does not increase, and good visibility can be provided without fluctuation of the viewing angle characteristic after the durability test.

  In the production of the polarizing plate protective film, functional layers such as an antistatic layer, a hard coat layer, a slippery layer, an adhesive layer, an antiglare layer, and a barrier layer may be coated before or after stretching. At this time, various surface treatments such as corona discharge treatment, plasma treatment, and chemical treatment can be performed as necessary.

  In the film forming process, the clip gripping portions at both ends of the cut optical film are pulverized or granulated as necessary, and then used as raw materials for the same type of optical film or different types of optical film. It may be reused as a raw material.

(Liquid crystal display device)
A polarizing plate comprising the functional film of the present invention as a polarizing plate protective film (including a case where it also serves as a retardation film) can exhibit a higher display quality than a normal polarizing plate, and is particularly multi-domain. Type liquid crystal display device, more preferably suitable for use in a multi-domain type liquid crystal display device by birefringence mode.

  The polarizing plate of the present invention includes an MVA (Multi-domain Vertical Alignment) mode, a PVA (Patterned Vertical Alignment) mode, a CPA (Continuous Pinwheel Alignment) mode, an OCB (Optical Compensated InP mode) It can be used, and is not limited to a specific liquid crystal mode and the arrangement of polarizing plates.

  The display quality of the liquid crystal display device is improved by the present invention, and since the contrast is improved and the resistance of the polarizing plate is improved, it is possible to display a moving image faithfully with less fatigue.

  In a liquid crystal display device including at least a polarizing plate including a retardation film, one polarizing plate including a polarizing plate protective film as the optical film of the present invention is disposed on the liquid crystal cell, or both sides of the liquid crystal cell. Place two in a row.

  In such a configuration, the polarizing plate protective film as the optical film of the present invention can optically compensate the liquid crystal cell.

  When the polarizing plate of the present invention is used in a liquid crystal display device, at least one polarizing plate in the liquid crystal display device may be the polarizing plate of the present invention.

  In the polarizing plate of the present invention, a polarizing plate protective film of a cellulose derivative is used on the surface opposite to the polarizing plate protective film as the optical film of the present invention as viewed from the polarizer, and a general-purpose TAC film or the like is used. Can do. The polarizing plate protective film located on the side far from the liquid crystal cell can be provided with another functional layer in order to improve the quality of the display device.

  For example, an anti-glare, anti-glare, scratch resistance, dust adhesion prevention, and an optical film containing a known functional layer as a display as a constituent for improving brightness, or may be attached to the polarizing plate surface of the present invention. It is not limited to these.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the embodiments of the present invention are not limited thereto.

Example 1
(Preparation of Sample 1-1)
A cellulose ester film 1-1 was produced by the melt casting method using the following composition 1.

Composition 1
Cellulose ester (cellulose acetate propionate (acetyl group substitution degree 1.5, propionyl group substitution degree 1.3, molecular weight Mn = 86,000, Mw / Mn = 2.5))
100 parts by mass Trimethylolpropane tribenzoate 10 parts by mass IRGANOX-1010 (manufactured by Ciba Japan Co., Ltd.) 0.5 parts by mass PEP-36 (manufactured by ADEKA Corporation) 0.1 parts by mass Sumizer-GS (Sumitomo Chemical Co., Ltd.) 0.3 parts by mass Glycerin monostearate 0.5 parts by mass TINUVIN 928 (manufactured by Ciba Japan Co., Ltd.) 1.5 parts by mass Seahoster KEP-30 (manufactured by Nippon Shokubai Co., Ltd.) 0.1 parts by mass The composition was dried at 80 ° C. for 6 hours to a moisture content of 200 ppm or less, and further dried with a vacuum nauter mixer at 80 ° C. and 1 Torr (1.3 × 10 ² Pa) for 3 hours to obtain a moisture content of 50 ppm. .

  The obtained mixture was melt-mixed at 235 ° C. using a twin-screw extruder and pelletized. At this time, an all screw type screw was used instead of a kneading disk in order to suppress heat generation due to shear during kneading.

  In addition, evacuation was performed from the vent hole, and volatile components generated during kneading were removed by suction. In addition, between the feeder, hopper, and extruder die supplied to the extruder and the cooling tank, a dry nitrogen gas atmosphere was used to prevent moisture from being absorbed into the resin and to remove oxygen.

  The first cooling roll and the second cooling roll were made of stainless steel having a diameter of 40 cm, and the surface was hard chrome plated. Further, oil for temperature adjustment (cooling fluid) was circulated inside to control the roll surface temperature to 130 ° C.

  The elastic touch roll had a diameter of 20 cm, the inner cylinder and the outer cylinder were made of stainless steel, and the surface of the outer cylinder was hard chrome plated. The wall thickness of the outer cylinder was 2 mm, and the surface temperature of the elastic touch roll was controlled at 130 ° C. by circulating temperature adjusting oil (cooling fluid) in the space between the inner cylinder and the outer cylinder.

  Using the above pellets, melted at 250 ° C. in a nitrogen atmosphere, extruded from the casting die onto the first cooling roll, and formed by pressing the melt extruded between the first cooling roll and the elastic touch roll. Sample 1-1 having a film thickness of 80 μm was obtained. The film thickness was controlled by adjusting the extrusion amount and the take-up speed.

  At this time, a T die having a lip clearance of 1.5 mm and an average surface roughness Ra of 0.01 μm was used. Further, an elastic touch roll having a 2 mm thick metal surface was pressed on the first cooling roll at a linear pressure of 10 kg / cm.

The film temperature on the touch roll side during pressing was 180 ° C. ± 1 ° C. (The film temperature on the touch roll side at the time of pressing here refers to the temperature of the film at the position where the touch roll on the first roll (cooling roll) is in contact with the non-contact thermometer by retreating the touch roll. (This refers to the average value of the film surface temperature measured at 10 points in the width direction from a position 50 cm away without a roll.)
Cellulose ester films 1-2 to 1-42 were obtained in the same manner as cellulose ester film 1-1 except that the composition of the additives was changed as shown in Tables 1 and 2.

[Production of hard coat film]
(Preparation of hard coat film 1)
Sample 1-1 was produced according to the following procedure using the cellulose ester film 1-1.

On the cellulose ester film 1, the following hard coat layer coating composition 1 is filtered through a polypropylene filter having a pore size of 0.4 μm to prepare a hard coat layer coating solution, which is applied using a micro gravure coater, and 70 After drying at 0 ° C., while applying nitrogen purge so that the oxygen concentration becomes 1.0 vol% or less, an ultraviolet lamp is used and the irradiation part has an illuminance of 100 mW / cm ² and an irradiation amount of 0.1 J / cm ^2. After the layer is cured and a hard coat layer having a dry film thickness of 9 μm is formed, the back coat layer coating composition 1 is continuously applied to the surface opposite to the surface on which the hard coat layer is applied so as to have a wet film thickness of 10 μm. It apply | coated with the extrusion coater and it was made to dry and the hard coat film 1-1 was produced and wound up.

<Hard coat layer composition 1>
(Preparation of fluorine-siloxane graft polymer 1)
Hereinafter, commercially available product names of materials used for preparing the fluorine-siloxane graft polymer 1 are shown.

Radical polymerizable fluororesin (A): Cefal coat CF-803 (hydroxyl value 60, number average molecular weight 15,000; manufactured by Central Glass Co., Ltd.)
One-end radical polymerizable polysiloxane (B): Silaplane FM-0721 (number average molecular weight 5,000; manufactured by Chisso Corporation)
Radical polymerization initiator: Perbutyl O (t-butylperoxy-2-ethylhexanoate; manufactured by NOF Corporation)
Curing agent: Sumidur N3200 (biuret-type prepolymer of hexamethylene diisocyanate; manufactured by Sumitomo Bayer Urethane Co., Ltd.)
[Synthesis of radical polymerizable fluororesin (A)]
In a glass reactor equipped with a mechanical stirrer, thermometer, condenser and dry nitrogen gas inlet, cefal coat CF-803 (1554 parts by mass), xylene (233 parts by mass), and 2-isocyanatoethyl methacrylate (6 3 parts by mass) and heated to 80 ° C. in a dry nitrogen atmosphere. After reacting at 80 ° C. for 2 hours and confirming that the absorption of isocyanate disappeared by the infrared absorption spectrum of the sample, the reaction mixture was taken out and 50% by mass of radically polymerizable fluororesin (A) via a urethane bond. Got.

  Next, the above synthesized radical polymerizable fluororesin (A) (26.1 parts by mass), xylene (19.5 parts) were added to a glass reactor equipped with a mechanical stirrer, a thermometer, a condenser and a dry nitrogen gas inlet. Parts by weight), n-butyl acetate (16.3 parts by weight), methyl methacrylate (2.4 parts by weight), n-butyl methacrylate (1.8 parts by weight), lauryl methacrylate (1.8 parts by weight), 2- Hydroxyethyl methacrylate (1.8 parts by mass), FM-0721 (5.2 parts by mass), and perbutyl O (0.1 parts by mass) were added and heated to 90 ° C. in a nitrogen atmosphere. Held for hours. Perbutyl O (0.1 part) was added, and the solution was further maintained at 90 ° C. for 5 hours to obtain a 35 mass% fluorine-siloxane graft polymer 1 solution having a weight average molecular weight of 171,000.

  The weight average molecular weight was determined by GPC. The mass% of the fluorine-siloxane graft polymer 1 was determined by HPLC (liquid chromatography).

  The following materials were stirred and mixed to obtain hard coat layer coating composition 1.

(Polyfunctional acrylate)
Pentaerythritol tetraacrylate 40 parts by weight Dipentaerythritol hexaacrylate 50 parts by weight Dipentaerythritol pentaacrylate 40 parts by weight (photopolymerization initiator)
Irgacure 184 (Ciba Specialty Chemicals) 5 parts by mass Irgacure 907 (Ciba Specialty Chemicals) 10 parts by mass (additive)
Fluoro-siloxane graft polymer 1 (35% by mass) 7 parts by mass Pentaerythritol tetrakis (3-mercaptobutyrate) 2.5 parts by mass (solvent)
Isopropyl alcohol (SP value = 23.5) 45 parts by mass Methyl ethyl ketone (SP value = 19.0) 105 parts by mass <Backcoat layer coating composition 1>
Diacetyl cellulose 0.6 parts by weight Acetone 35 parts by weight Methyl ethyl ketone 35 parts by weight Methanol 35 parts by weight A 2% methanol dispersion of silica particles (KE-P30, manufactured by Nippon Shokubai Co., Ltd.)
16 parts by mass Samples 1-2 to 1-42 were obtained in the same manner as Sample 1-1 except that the composition of the cellulose ester film additive and the solvent composition of the hard coat layer were changed as shown in Tables 1 and 2. It was.

  The samples 1-1 to 1-42 obtained were evaluated for haze and adhesion.

(Haze)
The haze of the sample was measured according to the method described in JIS K 7136. The measurement used Nippon Denshoku Industries Co., Ltd. turbidimeter NDH2000.

  The haze value is preferably smaller. If it is 0.5% or less, there is no practical problem, but it is particularly preferably 0.35% or less.

(Adhesion evaluation)
The sample was irradiated with light for 120 hours with a weather resistance tester (Isuper UV tester, manufactured by Iwasaki Electric Co., Ltd.), and then conditioned for 2 hours under conditions of a temperature of 25 ° C. and 60% RH. Next, on the surface on the side having the functional layer of each sample, a notch with 11 vertical and 11 horizontal cuts was made with a cutter knife in a grid pattern, and a total of 100 square squares were engraved, and polyester adhesive tape ( No. 31B, manufactured by Nitto Denko Corporation), the adhesion test was repeated three times at the same place. The presence or absence of peeling was visually observed, and the following four-stage evaluation was performed. If it is more than the Δ level, there is no practical problem, but the ○ level is preferable, and the ◎ level is more preferable.

◎: No peeling was observed at 100-th eye ○: Peeling at 100-th eye was within 2nd △: Peeling at 100-th eye, 3rd to 10-th eye ×: Peeling at 100-th eye Table 11 and Table 2 show the evaluation results.

  As is clear from the results shown in Tables 1 and 2, the haze of the sample according to the present invention is smaller and better than the comparative example. Further, in the adhesion evaluation, there is no or close to no peeling, and it can be seen that this point is also excellent.

Example 2
Using composition 1, a cellulose ester film having a film thickness of 80 μm was melt-formed in the same manner as in Example 1, and then stretched 1.3 times in the conveying direction at 155 ° C. by a stretching machine using a difference in peripheral speed of the roll. did. Next, it is introduced into a tenter having a preheating zone, a stretching zone, a holding zone, and a cooling zone (there is also a neutral zone for ensuring thermal insulation between the zones), and is 1. After stretching 5 times, the film was cooled to 30 ° C. while relaxing 2% in the width direction, then released from the clip, and the clip gripping part was cut off to obtain a cellulose ester film 2-1 having a film thickness of 40 μm.

  Further, a sample 2-1 was obtained in the same manner as in Example 1 using the hard coat layer coating composition 1.

  Samples 2-2 to 2-7 were obtained in the same manner as Sample 2-1, except that the composition of the additive and the draw ratio were changed as shown in Table 3. At this time, the film thickness before stretching was changed so that the film thickness after stretching was 40 μm. The film thickness before stretching was controlled by adjusting the extrusion amount and the take-up speed.

  Using the obtained samples 2-1 to 2-7, haze and pencil hardness were evaluated.

(Pencil hardness)
Using the test pencil specified by JIS-S6006, according to the pencil hardness evaluation method specified by JIS-K5400, the surface of the functional layer is scratched with 5 pencils of each hardness using a weight of 1 kg, up to one scratch. The hardness of was measured. Higher numbers are preferable because of higher hardness. If it is 2H, there is no practical problem, but 3H or more is preferable, and 4H or more is more preferable.

  The evaluation results are shown in Table 3.

  As is apparent from the results shown in Table 3, it can be seen that the samples according to the present invention have substantially no problem in haze and pencil hardness, and most of the samples are within the preferred range.

Example 3
Samples 3-1 to 3- in the same manner as in Sample 2-1, except that Mw / Mn and trimethylolpropane tribenzoate of the cellulose ester of Composition 1 shown in Example 1 were changed as shown in Table 4. 18 was produced. Samples 3-1 to 3-18 were used to measure haze, pencil hardness, and adhesion.

  The evaluation results are shown in Table 4.

  As is apparent from the results shown in Table 4, it can be seen that the samples according to the present invention have substantially no problem in haze, pencil hardness, and adhesion, and most of the samples are within the preferred range.

Example 4
[Preparation of antireflection film]
Next, the following high refractive index layer coating solution 1 was applied onto the hard coat films 1 to 42 prepared in Example 1, and further the low refractive index layer coating solution 1 was applied thereon and dried, followed by 120 ° C. And then cured by irradiating with ultraviolet rays, and a high refractive index layer having a thickness of 120 nm and a low refractive index layer having a thickness of 85 nm are provided and wound into a roll, and then at 60 ° C. for 5 days. Anti-reflection films 1 to 23 were produced by heat aging treatment. The refractive index of the high refractive index layer was 1.60, and the refractive index of the low refractive index layer was 1.38. The center line average roughness (Ra) of the surface of the low refractive index layer was 100 nm or less and was smooth.

(High refractive index layer coating solution 1)
Tetra (n) butoxytitanium 3 parts by weight Conductive ITO fine particles (ELCOM V2504, ITO sol, solid content 20% by weight, manufactured by Catalytic Chemical) 200 parts by weight Dipentaerythritol hexaacrylate (matrix) 50 parts by weight Irgacure 184 (initiating photopolymerization) Agent) 3 parts by mass γ-methacryloxypropylmethoxysilane (KBM503 manufactured by Shin-Etsu Chemical Co., Ltd.)
8 parts by mass Poly-n-butyl methacrylate (matrix) 5 parts by mass Propylene glycol monomethyl ether (PGME) 720 parts by mass Isopropyl alcohol 1470 parts by mass Methyl ethyl ketone (MEK) 250 parts by mass <Preparation of tetraethoxysilane hydrolyzate A>
Tetraethoxysilane hydrolyzate A was prepared by mixing 58 g of tetraethoxysilane and 114 g of ethanol and adding 60 g of an acetic acid aqueous solution (1%) thereto, followed by stirring at 25 ° C. for 1 hour.

(Low refractive index layer coating solution 1)
Tetraethoxysilane hydrolyzate A 59.5 parts by mass The following silica-based fine particles P-1 35 parts by mass γ-methacryloxypropyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., KBM503)
5 parts by mass FZ-2222 (Nihon Unicar, 10% propylene glycol monomethyl ether solution) 0.5 parts by mass Isopropyl alcohol 500 parts by mass Propylene glycol monomethyl ether (PGME) 300 parts by mass Methyl ethyl ketone (MEK) 100 parts by mass <Silica-based fine particles Preparation of 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% by mass and 1900 g of pure water was heated to 80 ° C. The pH of this reaction mother liquor at 80 ° C. is 10.5. In the mother liquor, 9000 g of 0.98 mass% sodium silicate aqueous solution as SiO ₂ and 9000 g of 1.02 mass% sodium aluminate aqueous solution as Al ₂ O ₃ Were added simultaneously. Meanwhile, the temperature of the reaction solution was kept at 80 ° C. The pH of the reaction solution at 80 ° C. rose to 12.5 immediately after the addition, and hardly changed thereafter. 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 with a solid content concentration of 20% by mass (step (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 silicic acid 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% by mass) was obtained (step (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% by mass, and concentrated hydrochloric acid (35.5%) is further added dropwise. Then, the pH at 35 ° C. was adjusted to 1.0, and dealumination was performed. Next, the aluminum salt dissolved in the ultrafiltration membrane was separated while adding 10 L of hydrochloric acid aqueous solution of pH 3 at 35 ° C. and 5 L of pure water, and a part of the constituent components of the core particles forming the first silica coating layer was removed. A dispersion of ₂ · Al 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 (SiO ₂ 28 mass%) 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. Next, a dispersion of silica-based fine particles (P-1) having a solid content concentration of 20% by mass in which the solvent was replaced with ethanol using an ultrafiltration membrane was prepared.

The thickness of the first silica coating layer of the hollow silica-based fine particles was 3 nm, the average particle size was 47 nm, MOx / SiO ₂ (molar ratio) was 0.0017, and the refractive index was 1.28. Here, the average particle diameter was measured by a dynamic light scattering method.

(Reflective color unevenness)
The reflected color unevenness was visually evaluated according to the following criteria.

  (Double-circle): The color tone change of reflected light is not recognized.

  ○: A change in the color tone of reflected light is observed in a very small part (less than 10% of the area).

  (Triangle | delta): The color tone change of reflected light is recognized partially (10 to 30% of an area).

  X: The color change of reflected light is recognized as a whole.

  The above evaluation results are shown in Tables 5 and 6, but the antireflection film produced using the hard coat film of the present invention has almost no or only a slight change in the color tone of the reflected light, and has excellent resistance. It was found that the reflection color was uneven.

Claims (5)

A functional film having a hard coat layer on the surface of a cellulose ester film produced by a melt film-forming method, wherein the cellulose ester film comprises at least one of glycerin fatty acid ester, diglycerin fatty acid ester, and sorbitan fatty acid ester 20 to 45% by mass of an organic solvent containing 0.05 to 2.0% by mass and having a solubility parameter of 18.5 to 21 (MPa) ^1/2 in the coating liquid of the hard coat layer. A functional film containing the functional film. The functional film according to claim 1, wherein the functional film is stretched within a range in which a total of a stretching ratio in a fluent direction and a stretching ratio in a direction perpendicular to the fluent direction is 20 to 300%. 3. The functional film according to claim 1, comprising 2 to 20% by mass of at least one of aromatic carboxylic esters of pentaerythritol. The functional film as described in any one of Claims 1-3 was used, The polarizing plate characterized by the above-mentioned. A liquid crystal display device using the polarizing plate according to claim 4.