JP2011099955A - Optical film, polarizing plate, and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical film which is improved in light leakage and prevented from being broken during film formation, and in which a retardation is developed; to provide a polarizing plate obtained by using the optical film and having good durability; and to provide a liquid crystal display obtained by using the polarizing plate and having a high image quality. <P>SOLUTION: The optical film includes an acrylic polymer having a lactone ring structure and a cellulose ester resin. The optical film includes a compound represented by general formula (1). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an optical film, a polarizing plate using the same, and a liquid crystal display device.

  Due to the thinness and lightness of the liquid crystal display, the production volume has increased greatly in recent years, and the demand for liquid crystal displays has increased. In addition, TVs using liquid crystal displays have the feature of being thin and light, and large TV sets that have not been achieved with TVs using cathode ray tubes have been produced. Demand for polarizers and polarizer protective films is also increasing.

  Cellulose ester resin film is a polarizing plate that protects a photographic negative film support and a polarizer used in a liquid crystal display because of its high transparency, low birefringence, and easy adhesion to a polarizer. Etc. have been used.

  However, the cellulose ester resin film has good mechanical properties, but light leakage when applied to a liquid crystal panel has been a problem. Therefore, it is necessary to generate a larger phase difference in order to improve light leakage.

  On the other hand, an acrylic resin film containing a lactone ring (for example, see Patent Documents 1 to 7) has been proposed as a film using a resin other than cellulose ester resin, and the acrylic resin film containing a lactone ring has a high heat resistance. In addition, the heat and moisture resistance is good and light leakage does not easily occur when applied to a liquid crystal panel, but the brittleness is poor.

  The inventor tried to form a film using these two resins in combination, and as a result, an optical film having good transparency and easy adhesion with a polarizer was obtained, which was useful. However, as a new problem, the problem that the film breaks due to the conveyance stress frequently occurred. Moreover, in order to develop the phase difference, high-stretching is necessary, but at this time, breakage occurred frequently.

  Therefore, the present inventor has conducted various studies on methods for expressing retardation and causing no breakage in an optical film using a cellulose ester resin and an acrylic resin containing a lactone ring. By adding a specific compound to the acrylic resin containing, an optical film with no breakage and little light leakage could be obtained.

JP 2007-254726 A JP 2007-100044 A JP 2007-254727 A JP 2007-297619 A JP 2008-9378 A JP 2008-299096 A JP 2009-1744 A

  This invention is made | formed in view of the said subject, The objective is to provide the optical film by which light leakage is improved, there is no fracture | rupture at the time of film forming, and a phase difference is expressed. Furthermore, it is providing the durable polarizing plate using such an optical film, and a liquid crystal display device with high image quality.

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

  1. An optical film containing an acrylic polymer having a lactone ring structure and a cellulose ester resin, wherein the optical film contains a compound represented by the following general formula (1).

(Wherein R ^{1 to} R ⁷ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a substituent, at least one of R ^{1 to} R ⁵ represents an electron donating group, and R ⁸ represents a hydrogen atom. , An alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and 6 to 6 carbon atoms 12 represents an aryloxy group, an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, an acyloxy group, a cyano group, or a halogen atom.)
2. 2. The optical film as described in 1 above, wherein the electron donating group of the compound represented by the general formula (1) is an alkoxy group.

  3. 3. The optical film as described in 1 or 2 above, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2).

(In the formula, R ² , R ⁴ and R ⁵ each independently represent a hydrogen atom or a substituent, R ²¹ and R ²² each independently represent an alkyl group having 1 to 4 carbon atoms, and X ¹ represents 2 carbon atoms. Represents a -7 alkynyl group, an aryl group having 6-12 carbon atoms, an alkoxycarbonyl group having 2-12 carbon atoms, an acylamino group having 2-7 carbon atoms, or a cyano group.)
4). A polarizing plate comprising the optical film according to any one of 1 to 3 on at least one surface of a polarizer.

  5. 5. A liquid crystal display device using the polarizing plate according to 4 above on at least one surface of a liquid crystal cell.

  According to the present invention, there is provided an optical film that improves light leakage, does not break during film formation, and exhibits a phase difference, a polarizing plate with good durability using the optical film, and a liquid crystal display device with high image quality. it can.

It is a figure which shows the state of the optical film original fabric storage.

  As a result of intensive studies in view of the above problems, the present inventor is an optical film containing an acrylic polymer having a lactone ring structure and a cellulose ester resin, and the optical film is represented by the general formula (1). As a result of finding the optical film containing the compound represented, an optical film that improves light leakage, does not break during film formation, and develops a phase difference is obtained.

  A cellulose ester resin-rich portion and an acrylic polymer-rich portion are generated in the plane of the hybrid film composed of an acrylic polymer having a lactone ring structure and a cellulose ester resin, and as a result, a residual solvent is generated in the plane of the film. It was found that a portion having a different amount was generated, and that fracture occurred when a stress such as a slit was applied to the interface.

  Since the additive of the present invention (compound represented by the general formula (1)) has good compatibility between the acrylic polymer having a lactone ring structure and the ester portion of the cellulose ester resin, the compatibility between the two is promoted. These effects are considered to be manifested.

  Hereinafter, the present invention will be described in detail, but the present invention is not limited thereto.

<< Compound Represented by Formula (1) >>
The present invention is characterized in that the optical film contains the compound represented by the general formula (1).

  The compound represented by the general formula (1) used in the present invention will be described.

In the general formula (1), R ^{1 to} R ⁷ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a substituent, and the substituent T described below can be applied to the substituent. At least one of R ^{1 to} R ⁵ represents an electron donating group. It is preferred that one of R ¹ , R ³ or R ⁵ is an electron donating group, and more preferred that R ³ is an electron donating group.

The electron donating group is one having Hammet's σ _p value of 0 or less. Rev. 91, 165 (1991) with a Hammett's σ _p value of 0 or less, preferably −0.85 to 0. Examples thereof include an alkyl group, an alkoxy group, an amino group, and a hydroxyl group. The electron donating group is preferably an alkyl group or an alkoxy group, more preferably an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, particularly preferably Is a C1-C4).

R ¹ is preferably a hydrogen atom or an electron-donating group, more preferably an alkyl group, an alkoxy group, an amino group, or a hydroxyl group, and still more preferably an alkyl group having 1 to 4 carbon atoms or a carbon number 1 to 12 Particularly preferably an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, particularly preferably 1 to 4 carbon atoms), Most preferred is a methoxy group.

R ² is preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group or a hydroxyl group, more preferably a hydrogen atom, an alkyl group or an alkoxy group, still more preferably a hydrogen atom or an alkyl group (preferably a carbon number). 1 to 4, more preferably a methyl group), an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to carbon atoms). 4). Particularly preferred are a hydrogen atom, a methyl group and a methoxy group.

R ³ is preferably a hydrogen atom or an electron donating group, more preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group, or a hydroxyl group, still more preferably an alkyl group or an alkoxy group, particularly preferably. An alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms). Most preferred are n-propoxy group, ethoxy group and methoxy group.

R ⁴ is preferably a hydrogen atom or an electron donating group, more preferably a hydrogen atom, an alkyl group, an alkoxy group, an amino group, or a hydroxyl group, and still more preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. And an alkoxy group having 1 to 12 carbon atoms (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms). Is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms, and most preferably a hydrogen atom, a methyl group, or a methoxy group.

Preferred groups for R ⁵ are the same as those listed for R ² .

R ⁶ , R ⁷ , R ⁹ and R ¹⁰ are preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or a halogen atom, more preferably a hydrogen atom or a halogen atom. More preferably a hydrogen atom.

R ⁸ is a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, or an alkoxy group having 1 to 12 carbon atoms. Represents an aryloxy group having 6 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, an acyloxy group, a cyano group, or a halogen atom, and if possible, has a substituent. The substituent T described later can be applied as the substituent.

R ⁸ is preferably an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, or an alkoxycarbonyl having 2 to 12 carbon atoms. Group, an acylamino group having 2 to 12 carbon atoms, and a cyano group, more preferably an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, and a carbon number An acylamino group having 2 to 12 carbon atoms, and a cyano group, and more preferably an alkynyl group having 2 to 7 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, and 2 to 7 carbon atoms. Acylamino group and cyano group, particularly preferably phenylethynyl group, phenyl group, p-cyanophenyl group, p-methoxyphenyl group, benzoylamino group, and n-propyl group. A poxycarbonyl group, an ethoxycarbonyl group, a methoxycarbonyl group, and a cyano group.

  Of the compounds represented by the general formula (1), a compound represented by the following general formula (1-A) is more preferable.

In the formula, R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ and R ¹⁰ are respectively synonymous with those in the general formula (1), and preferred ranges are also the same. is there.

In the formula, R ¹¹ represents an alkyl group, and the alkyl group represented by R ¹¹ may be linear or branched, and may further have a substituent. Preferably it is a C1-C12 alkyl group, More preferably, it is a C1-C8 alkyl group, More preferably, it is a C1-C6 alkyl group, Most preferably, it is a C1-C4 alkyl group (for example, methyl) Group, ethyl group, n-propyl group, iso-propyl group, n-butyl group, iso-butyl group, tert-butyl group, etc.).

  Of the compounds represented by the general formula (1), a compound represented by the following general formula (1-B) is more preferable.

In the formula, R ¹ , R ² , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁹ and R ¹⁰ have the same meanings as those in the general formula (1), and preferred ranges are also the same.

In the formula, R ¹¹ has the same meaning as those in formula (1-A), and the preferred range is also the same.

  In the formula, X is an alkyl group having 1 to 4 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and an aryloxy group having 6 to 12 carbon atoms. Represents an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, a carbonyl group, a cyano group, or a halogen atom.

When all of R ¹ , R ² , R ⁴ and R ⁵ are hydrogen atoms, X is preferably an alkyl group, alkynyl group, aryl group, alkoxy group or aryloxy group, more preferably an aryl group or alkoxy group. Group, an aryloxy group, more preferably an alkoxy group (preferably having 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms, still more preferably 1 to 6 carbon atoms, and particularly preferably 1 to 4 carbon atoms). And particularly preferably a methoxy group, a methoxy group, an n-propoxy group, an iso-propoxy group or an n-butoxy group.

When at least one of R ¹ , R ² , R ⁴ and R ⁵ is a substituent, X is preferably an alkynyl group having 2 to 12 carbon atoms, an aryl group having 6 to 12 carbon atoms, or 2 to 12 carbon atoms. An alkoxycarbonyl group, an acylamino group having 2 to 12 carbon atoms, and a cyano group, and more preferably an alkynyl group having 2 to 7 carbon atoms, an aryl group having 6 to 12 carbon atoms, and an alkoxycarbonyl group having 2 to 6 carbon atoms. A C2-C7 acylamino group and a cyano group, particularly preferably a phenylethynyl group, a phenyl group, a p-cyanophenyl group, a p-methoxyphenyl group, a benzoylamino group, an n-propoxycarbonyl group, and an ethoxycarbonyl group. Group, methoxycarbonyl group and cyano group.

  Of the compounds represented by the general formula (1), a compound represented by the following general formula (1-C) is more preferable.

In the formula, R ¹ , R ² , R ⁴ , R ⁵ , R ¹¹ and X have the same meanings as those in formula (1-B), and preferred ranges are also the same.

  Of the compounds represented by the general formula (1), a compound represented by the following general formula (2) is more preferable.

In formula, R < ² >, R < ⁴ > and R < ⁵ > are synonymous with those in General formula (1-C), and their preferable ranges are also the same. R ²¹ and R ²² each independently represents an alkyl group having 1 to 4 carbon atoms. X ¹ is an alkynyl group having 2 to 7 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, preferably an alkoxycarbonyl group having 2 to 6 carbon atoms, an acylamino group having 2 to 7 carbon atoms, Or represents a cyano group.

R ²¹ represents an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, and more preferably an ethyl group or a methyl group.

R ²² represents an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, more preferably an ethyl group or a methyl group, and still more preferably a methyl group.

X ¹ is an alkynyl group having 2 to 7 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxycarbonyl group having 2 to 12 carbon atoms, preferably an alkoxycarbonyl group having 2 to 6 carbon atoms, and an acylamino group having 2 to 7 carbon atoms. Group, cyano group, preferably phenylethynyl group, phenyl group, p-cyanophenyl group, p-methoxyphenyl group, benzoylamino group, n-propoxycarbonyl group, ethoxycarbonyl group, methoxycarbonyl group, cyano group is there.

  Of the compounds represented by the general formula (1), a compound represented by the following general formula (1-E) is more preferable.

In the formula, R ² , R ⁴ and R ⁵ have the same meanings as those in the general formula (2), and the preferred ranges are also the same, but any one is a group represented by —OR ¹³ (R ¹³ Is an alkyl group having 1 to 4 carbon atoms. R ²¹ , R ²² and X ¹ have the same meanings as those in formula (2), and preferred ranges are also the same.

In the formula, R ² , R ⁴ and R ⁵ have the same meanings as those in the general formula (2), and the preferred range is also the same, but any one is a group represented by —OR ¹³ (R ¹³ Is an alkyl group having 1 to 4 carbon atoms.), Preferably R ⁴ and R ⁵ are groups represented by —OR ¹³ , more preferably R ⁴ is a group represented by —OR ¹³ .

R ¹³ represents an alkyl group having 1 to 4 carbon atoms, preferably an alkyl group having 1 to 3 carbon atoms, more preferably an ethyl group or a methyl group, and still more preferably a methyl group.

  The aforementioned substituent T will be described below.

  Examples of the substituent T include an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methyl, ethyl, iso-propyl, tert-butyl. , N-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably carbon atoms). 2 to 8, for example, vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), an alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably carbon). 2 to 8, for example, propargyl, 3-pentynyl, etc.), an aryl group (preferably having 6 to 30 carbon atoms) Preferably it has 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyl, p-methylphenyl, naphthyl and the like, and a substituted or unsubstituted amino group (preferably having 0 to 20 carbon atoms). More preferably 0 to 10 carbon atoms, particularly preferably 0 to 6 carbon atoms, such as amino, methylamino, dimethylamino, diethylamino, dibenzylamino, etc.), an alkoxy group (preferably having 1 carbon atom). To 20, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms, such as methoxy, ethoxy, butoxy, etc.), an aryloxy group (preferably 6 to 20 carbon atoms, more preferably). Has 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, and examples thereof include phenyloxy and 2-naphthyloxy. An acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms such as acetyl, benzoyl, formyl, pivaloyl, etc.), an alkoxycarbonyl group. (Preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, and particularly preferably 2 to 12 carbon atoms, such as methoxycarbonyl, ethoxycarbonyl, etc.), aryloxycarbonyl group (preferably carbon 7 to 20, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 10 carbon atoms, such as phenyloxycarbonyl, etc.), an acyloxy group (preferably 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as acetoxy, benzoyloxy, etc. Is mentioned. ), An acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 10 carbon atoms, such as acetylamino, benzoylamino, etc.), an alkoxycarbonylamino group (Preferably having 2 to 20 carbon atoms, more preferably having 2 to 16 carbon atoms, and particularly preferably having 2 to 12 carbon atoms, such as methoxycarbonylamino), an aryloxycarbonylamino group (preferably having a carbon number) 7 to 20, more preferably 7 to 16 carbon atoms, particularly preferably 7 to 12 carbon atoms, such as phenyloxycarbonylamino, and the like, sulfonylamino group (preferably 1 to 20 carbon atoms, more preferably Has 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methanesulfonylamino, And sulfamoyl groups (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms, such as sulfamoyl, methylsulfamoyl, dimethyl). Sulfamoyl, phenylsulfamoyl, etc.), a carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as carbamoyl, methyl Carbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc.), alkylthio groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio, ethylthio, etc. An arylthio group (preferably having 6 to 6 carbon atoms). 0, more preferably 6 to 16 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio, etc.), alkylsulfonyl group or arylsulfonyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as mesyl, tosyl, etc.), alkylsulfinyl group or arylsulfinyl group (preferably 1 to 20 carbon atoms, more preferably 1 carbon atom) -16, particularly preferably having 1 to 12 carbon atoms, such as methanesulfinyl, benzenesulfinyl, etc.), ureido groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably C1-C12, for example, ureido, methylureido, phenylureido, etc. are mentioned. ), Phosphoric acid amide groups (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include diethyl phosphoric acid amide and phenyl phosphoric acid amide. ), Hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, Heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom, a sulfur atom, specifically, for example, imidazolyl, pyridyl, quinolyl, furyl, piperidyl Morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, etc.), silyl group Preferably, 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, particularly preferably 3 to 24 carbon atoms, e.g., trimethylsilyl, triphenylsilyl and the like) and the like. These substituents may be further substituted.

  Moreover, when there are two or more substituents, they may be the same or different. If possible, they may be linked together to form a ring.

  Hereinafter, the compound represented by the general formula (1) will be described in detail with specific examples, but the present invention is not limited to the following specific examples.

  The compound represented by the general formula (1) of the present invention can be synthesized by a general ester reaction of a substituted benzoic acid and a phenol derivative, and any reaction may be used as long as it is an ester bond forming reaction. Examples thereof include a method of converting a substituted benzoic acid to an acid halide and then condensing with phenol, a method of dehydrating condensation of a substituted benzoic acid and a phenol derivative using a condensing agent or a catalyst, and the like. In view of the production process and the like, a method in which the substituted benzoic acid is functionally converted to an acid halide and then condensed with phenol is preferable.

  Reaction solvents include hydrocarbon solvents (preferably toluene and xylene), ether solvents (preferably dimethyl ether, tetrahydrofuran, dioxane, etc.), ketone solvents, ester solvents, acetonitrile, dimethylformamide, dimethyl Acetamide or the like can be used. These solvents may be used alone or in admixture of several kinds, and preferred reaction solvents are toluene, acetonitrile, dimethylformamide and dimethylacetamide.

  The reaction temperature is preferably 0 to 150 ° C, more preferably 0 to 100 ° C, still more preferably 0 to 90 ° C, and particularly preferably 20 ° C to 90 ° C. In this reaction, it is preferable not to use a base. When a base is used, either an organic base or an inorganic base may be used, preferably an organic base such as pyridine, tertiary alkylamine (preferably triethylamine, ethyldiisopropyl). Pyramine and the like).

  The method for synthesizing the compound of the present invention is specifically described below, but the present invention is not limited by the following specific examples.

[Synthesis Example 1: Synthesis of Exemplified Compound A-2]
After heating 106.1 g (0.5 mol) of 2,4,5-trimethoxybenzoic acid, 340 ml of toluene and 1 ml of dimethylformamide to 60 ° C., 65.4 g (0.55 mol) of thionyl chloride was slowly added dropwise. Heated at 65-70 ° C. for 2 hours. Thereafter, a solution prepared by previously dissolving 71.5 g (0.6 mol) of 4-cyanophenol in 150 ml of acetonitrile was slowly added dropwise. After completion of the addition, the mixture was heated and stirred at 80 to 85 ° C. for 2 hours. After cooling the reaction solution to room temperature, liquid separation operation was performed with ethyl acetate (1 L) and water. After removing water from the obtained organic phase with magnesium sulfate, about 500 ml of the solvent was distilled off under reduced pressure, and 1 L of methanol was added. And recrystallization operation was performed. The precipitated crystals were collected by filtration to obtain 125.4 g (yield 80%) of the target compound as white crystals. The compound was identified by ¹ H-NMR (400 MHz) and mass spectrum.

[Synthesis Example 2: Synthesis of Exemplified Compound A-25]
After heating 24.7 g (149 mmol) of 4-ethoxybenzoic acid, 100 ml of toluene and 1 ml of dimethylformamide to 60 ° C., 19.5 g (164 mmol) of thionyl chloride was slowly added dropwise, and the mixture was stirred with heating at 60 ° C. for 2 hours. . Thereafter, a solution prepared by previously dissolving 25.0 g (165 mmol) of 4-propoxyphenol in 50 ml of acetonitrile was slowly added and stirred at 80 ° C. for 4 hours. After cooling the reaction solution to room temperature, 100 ml of methanol was added. The precipitated crystals were collected by filtration, 100 ml of methanol was added to the obtained solid, and recrystallization was performed. The obtained crystals were collected by filtration to obtain 33.9 g of the target compound as white crystals (yield 76%). Obtained. The compound was identified by ¹ H-NMR (400 MHz) and mass spectrum.

<< Acrylic polymer having a lactone ring structure >>
One feature of the present invention is that the optical film contains an acrylic polymer having a lactone ring structure.

  The acrylic polymer having a lactone ring structure preferably has a lactone ring structure represented by the following general formula (3).

^{(Wherein, R 1, R 2, R} 3 each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)
Examples of the organic residue represented by R ¹ include an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, and an aryl group. R ² is preferably a hydrogen atom.

Examples of the organic residue represented by R ² include an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group, a hydroxyalkyl group having 1 to 8 carbon atoms, and — (CH ₂ ). _{^{mNR 11 R 12, - (CH}} 2) mN (R 11 R 12 R 13) + · M -, or _{- (C 2 H 4 O)} pR 14 , and the like. Here, R ¹¹ , R ¹² and R ¹³ may be the same or different and each is an alkyl group having 1 to 8 carbon atoms, R ¹⁴ is an alkyl group having 1 to 18 carbon atoms, and m = 2. to 5, p = is 1 to 80, M ^- is _{^{Cl -, Br -, SO 4}} 2-, PO 4 3-, CH 3 COO - or HCOO ^- a. R ² is preferably a hydrogen atom or an alkyl group having 1 to 18 carbon atoms, more preferably a hydrogen atom, a methyl group, or an ethyl group.

Examples of the organic residue represented by R ³ include an alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aryl group, and a hydroxyalkyl group having 1 to 8 carbon atoms. R ³ is preferably a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or a hydroxyalkyl group having 1 to 8 carbon atoms, more preferably a hydrogen atom, a methyl group, or a 2-hydroxyethyl group.

  The content ratio of the acrylic polymer having a lactone ring structure represented by the general formula (3) is preferably 5 to 90% by mass with respect to the total of the acrylic polymer having a lactone ring structure and the cellulose ester resin. Preferably it is 10-70 mass%, More preferably, it is 10-60 mass%, Most preferably, it is 10-50 mass%.

  An acrylic polymer having a lactone ring structure may be included in combination with another acrylic polymer, and an acrylic polymer obtained by combining an acrylic polymer having a lactone ring structure with another acrylic polymer. The content ratio of the total amount of the polymer is preferably 5 to 90% by mass, more preferably 10 to 70% by mass, further preferably 10 to 60% by mass, and particularly preferably 10 to 50% by mass.

  The acrylic polymer having a lactone ring structure may have a structure other than the lactone ring structure represented by the general formula (3). The structure other than the lactone ring structure represented by the general formula (3) is not particularly limited, but a (meth) acrylic acid ester and a hydroxyl group as described later as a method for producing an acrylic polymer having a lactone ring A polymer structural unit (repeating structural unit) constructed by polymerizing at least one selected from a monomer, an unsaturated carboxylic acid, and a monomer represented by the following general formula (4a) is preferable.

(Wherein R ⁴ represents a hydrogen atom or a methyl group, X represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group, an —OAc group, a —CN group, a —CO—R ⁵ group, or —C It represents ^{-O-R 6} group, Ac group represents an acetyl group, ^{R 5} and ^{R 6} represents a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)
The content ratio of the structure other than the lactone ring structure represented by the general formula (3) in the acrylic polymer having a lactone ring structure is a polymer structural unit constructed by polymerizing (meth) acrylate ester (repeatedly) In the case of a structural unit), it is preferably 10 to 95% by mass, more preferably 10 to 90% by mass, further preferably 40 to 90% by mass, particularly preferably 50 to 90% by mass, and polymerize a hydroxyl group-containing monomer. In the case of a polymer structural unit (repeating structural unit) constructed as described above, preferably 0 to 30% by mass, more preferably 0 to 20% by mass, still more preferably 0 to 15% by mass, particularly preferably 0 to 10% by mass. %. In the case of a polymer structural unit (repeating structural unit) constructed by polymerizing an unsaturated carboxylic acid, it is preferably 0 to 30% by mass, more preferably 0 to 20% by mass, still more preferably 0 to 15% by mass, particularly Preferably it is 0-10 mass%. In the case of a polymer structural unit (repeating structural unit) constructed by polymerizing the monomer represented by the general formula (4a), it is preferably 0 to 30% by mass, more preferably 0 to 20% by mass, and still more preferably Is 0 to 15% by mass, particularly preferably 0 to 10% by mass.

  The method for producing the acrylic polymer having a lactone ring structure is not particularly limited, but is preferably obtained after obtaining a polymer (a) having a hydroxyl group and an ester group in the molecular chain by a polymerization step. The polymer (a) is obtained by subjecting the polymer (a) to a lactone cyclization condensation step for introducing a lactone ring structure into the polymer by heat treatment.

  In the polymerization step, a polymer having a hydroxyl group and an ester group in the molecular chain is obtained by performing a polymerization reaction of a monomer component containing a monomer represented by the following general formula (3a).

(Wherein R ⁷ and R ⁸ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms.)
Examples of the monomer represented by the general formula (3a) include methyl 2- (hydroxymethyl) acrylate, ethyl 2- (hydroxymethyl) acrylate, isopropyl 2- (hydroxymethyl) acrylate, 2- ( Hydroxymethyl) normal butyl acrylate, tertiary butyl 2- (hydroxymethyl) acrylate, and the like. Among these, 2- (hydroxymethyl) methyl acrylate and 2- (hydroxymethyl) ethyl acrylate are preferable, and 2- (hydroxymethyl) methyl acrylate is particularly preferable in that the effect of the present invention is sufficiently exhibited. . The monomer represented by the general formula (3a) may be used alone or in combination of two or more.

  The content ratio of the monomer represented by the general formula (3a) in the monomer component provided in the polymerization step is preferably 5 to 90% by mass, more preferably 10 to 70% by mass, and still more preferably 10 to 60%. It is 10 mass%, Most preferably, it is 10-50 mass%.

  The monomer component used in the polymerization step may contain a monomer other than the monomer represented by the general formula (3a). Such a monomer is not particularly limited. For example, (meth) acrylic acid ester, a hydroxyl group-containing monomer, an unsaturated carboxylic acid, and a monomer represented by the general formula (2a) are preferably exemplified. It is done. Only one type of monomer other than the monomer represented by formula (3a) may be used, or two or more types may be used in combination.

  The (meth) acrylic acid ester is not particularly limited as long as it is a (meth) acrylic acid ester other than the monomer represented by the general formula (3a). For example, methyl acrylate, ethyl acrylate, and acrylic acid n -Acrylic esters such as butyl, isobutyl acrylate, t-butyl acrylate, cyclohexyl acrylate, benzyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacrylic acid methacrylic acid esters such as t-butyl, cyclohexyl methacrylate, and benzyl methacrylate; and the like. These may be used alone or in combination of two or more. Among these, methyl methacrylate is particularly preferable from the viewpoint of sufficiently exerting the effects of the present invention.

  When using a (meth) acrylic acid ester other than the monomer represented by the general formula (3a), the content ratio in the monomer component to be subjected to the polymerization step is sufficient to exert the effect of the present invention. The content is preferably 10 to 95% by mass, more preferably 10 to 90% by mass, still more preferably 40 to 90% by mass, and particularly preferably 50 to 90% by mass.

  The hydroxyl group-containing monomer is not particularly limited as long as it is a hydroxyl group-containing monomer other than the monomer represented by the general formula (3a). For example, α-hydroxymethyl styrene, α-hydroxyethyl styrene, 2 -(Hydroxyethyl) acrylic acid esters such as methyl (hydroxyethyl) acrylate; 2- (hydroxyalkyl) acrylic acid such as 2- (hydroxyethyl) acrylic acid; and the like. Or two or more of them may be used in combination.

  In the case of using a hydroxyl group-containing monomer other than the monomer represented by the general formula (3a), the content ratio in the monomer component to be subjected to the polymerization step is sufficient to exert the effect of the present invention. Preferably it is 0-30 mass%, More preferably, it is 0-20 mass%, More preferably, it is 0-15 mass%, Most preferably, it is 0-10 mass%.

  Examples of the unsaturated carboxylic acid include acrylic acid, methacrylic acid, crotonic acid, α-substituted acrylic acid, α-substituted methacrylic acid and the like. These may be used alone or in combination of two or more. May be. Among these, acrylic acid and methacrylic acid are preferable in that the effects of the present invention are sufficiently exhibited.

  When using an unsaturated carboxylic acid, the content ratio in the monomer component to be subjected to the polymerization step is preferably 0 to 30% by mass, more preferably 0 to 20% by mass, in order to sufficiently exhibit the effects of the present invention. %, More preferably 0 to 15% by mass, particularly preferably 0 to 10% by mass.

  Examples of the monomer represented by the general formula (4a) include styrene, vinyl toluene, α-methyl styrene, acrylonitrile, acryloyl morpholine, methyl vinyl ketone, ethylene, propylene, vinyl acetate, and N-vinyl pyrrolidone. These may be used alone or in combination of two or more. Among these, styrene and α-methylstyrene are particularly preferable in that the effects of the present invention are sufficiently exhibited.

  When the monomer represented by the general formula (4a) is used, the content ratio in the monomer component to be subjected to the polymerization step is preferably 0 to 30% by mass in order to sufficiently exhibit the effects of the present invention. More preferably, it is 0-20 mass%, More preferably, it is 0-15 mass%, Most preferably, it is 0-10 mass%.

  The form of the polymerization reaction for polymerizing the monomer component to obtain a polymer having a hydroxyl group and an ester group in the molecular chain is preferably a polymerization form using a solvent, and solution polymerization is particularly preferred.

  The polymerization temperature and polymerization time vary depending on the type of monomer used, the ratio of use, etc., but preferably the polymerization temperature is 0 to 150 ° C. and the polymerization time is 0.5 to 20 hours, more preferably polymerization. The temperature is 80 to 140 ° C. and the polymerization time is 1 to 10 hours.

  In the case of a polymerization form using a solvent, the polymerization solvent is not particularly limited. For example, aromatic hydrocarbon solvents such as toluene, xylene, and ethylbenzene; ketone solvents such as methyl ethyl ketone and methyl isobutyl ketone ketone; ethers such as tetrahydrofuran A solvent; etc. are mentioned, Only 1 type of these may be used and 2 or more types may be used together. Moreover, since the residual volatile matter of the lactone ring containing polymer finally obtained will increase when the boiling point of the solvent to be used is too high, a thing with a boiling point of 50-200 degreeC is preferable.

  During the polymerization reaction, a polymerization initiator may be added as necessary. Although it does not specifically limit as a polymerization initiator, For example, cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, t-butylperoxyisopropyl carbonate, t-amyl Organic peroxides such as peroxy-2-ethylhexanoate; 2,2′-azobis (isobutyronitrile), 1,1′-azobis (cyclohexanecarbonitrile), 2,2′-azobis (2, Azo compounds such as 4-dimethylvaleronitrile), and the like. These may be used alone or in combination of two or more. What is necessary is just to set the usage-amount of a polymerization initiator suitably according to the combination of the monomer to be used, reaction conditions, etc., and it does not specifically limit.

  When performing the polymerization, it is preferable to control the concentration of the produced polymer in the polymerization reaction mixture to be 50% by mass or less in order to suppress gelation of the reaction solution. Specifically, when the concentration of the produced polymer in the polymerization reaction mixture exceeds 50% by mass, it is preferable that the polymerization solvent is appropriately added to the polymerization reaction mixture and controlled to be 50% by mass or less. . The concentration of the produced polymer in the polymerization reaction mixture is more preferably 45% by mass or less, and further preferably 40% by mass or less. In addition, since productivity will fall when the density | concentration of the polymer in a polymerization reaction mixture is too low, it is preferable that the density | concentration of the polymer in a polymerization reaction mixture is 10 mass% or more, and is 20 mass% or more. It is more preferable.

  The form in which the polymerization solvent is appropriately added to the polymerization reaction mixture is not particularly limited, and the polymerization solvent may be added continuously or intermittently. By controlling the concentration of the produced polymer in the polymerization reaction mixture in this way, the gelation of the reaction solution can be more sufficiently suppressed, and in particular, to increase the lactone ring content and improve the heat resistance. Even when the ratio of the hydroxyl group to the ester group in the molecular chain is increased, gelation can be sufficiently suppressed. The polymerization solvent to be added may be the same type of solvent used during the initial charging of the polymerization reaction or may be a different type of solvent, but is the same as the solvent used during the initial charging of the polymerization reaction. It is preferable to use different types of solvents. Further, the polymerization solvent to be added may be only one type of solvent or a mixed solvent of two or more types.

  The polymerization reaction mixture obtained when the above polymerization step is completed usually contains a solvent in addition to the obtained polymer, but it is necessary to completely remove the solvent and take out the polymer in a solid state. Rather, it is preferably introduced into the subsequent lactone cyclization condensation step in a state containing a solvent. If necessary, after taking out in a solid state, a solvent suitable for the subsequent lactone cyclization condensation step may be added again.

  The polymer obtained in the polymerization step is a polymer (a) having a hydroxyl group and an ester group in the molecular chain, and the weight average molecular weight of the polymer (a) is preferably 1,000 to 1,000,000. 000, more preferably 5,000 to 500,000, particularly preferably 10,000 to 200,000. The polymer (a) obtained in the polymerization step is subjected to heat treatment in the subsequent lactone cyclization condensation step, whereby a lactone ring structure is introduced into the polymer to become a lactone ring-containing polymer.

  The reaction for introducing the lactone ring structure into the polymer (a) is a reaction in which a hydroxyl group and an ester group present in the molecular chain of the polymer (a) are cyclized and condensed to form a lactone ring structure by heating. The cyclized condensation produces alcohol as a by-product. By forming the lactone ring structure in the molecular chain of the polymer (in the main skeleton of the polymer), the effects of the present invention can be sufficiently exerted. If the reaction rate of the cyclization condensation reaction leading to the lactone ring structure is insufficient, the effect will be insufficient, or a condensation reaction will occur during the molding process due to the heat treatment during molding, and the resulting alcohol will cause bubbles in the molded product. Or silver streak, which is not preferable.

  The lactone ring-containing polymer obtained in the lactone cyclization condensation step preferably has a lactone ring structure represented by the general formula (3).

  The method for heat-treating the polymer (a) is not particularly limited, and a known method can be used. For example, you may heat-process the polymerization reaction mixture containing the solvent obtained by the superposition | polymerization process as it is. Moreover, you may heat-process using a ring-closing catalyst as needed in presence of a solvent. Further, the heat treatment can be performed using a heating furnace or reaction apparatus having a vacuum apparatus or a devolatilizing apparatus for removing volatile components, an extruder having a devolatilizing apparatus, or the like.

  In carrying out the cyclization condensation reaction, in addition to the polymer (a), another thermoplastic resin may coexist. Further, when performing the cyclization condensation reaction, if necessary, an esterification catalyst or a transesterification catalyst such as p-toluenesulfonic acid generally used as a catalyst for the cyclization condensation reaction may be used. Organic carboxylic acids such as propionic acid, benzoic acid, acrylic acid, and methacrylic acid may be used as a catalyst. As disclosed in JP-A-61-254608 and JP-A-61-261303, basic compounds, organic carboxylates, carbonates and the like may be used.

  In carrying out the cyclization condensation reaction, it is preferable to use an organic phosphorus compound as a catalyst as disclosed in JP-A No. 2001-151814. By using an organophosphorus compound as a catalyst, the cyclization condensation reaction rate can be improved, and coloring of the resulting lactone ring-containing polymer can be greatly reduced. Furthermore, by using an organophosphorus compound as a catalyst, it is possible to suppress a decrease in molecular weight that can occur when a devolatilization step described later is used in combination, and to impart excellent mechanical strength.

  Although the usage-amount of the catalyst used in the case of a cyclization condensation reaction is not specifically limited, Preferably it is 0.001-5 mass% with respect to a polymer (a), More preferably, it is 0.01-2.5 mass%. More preferably, it is 0.01-1 mass%, Most preferably, it is 0.05-0.5 mass%. If the amount of the catalyst used is less than 0.001% by mass, the reaction rate of the cyclization condensation reaction may not be improved sufficiently. On the other hand, if the amount exceeds 5% by mass, coloring may occur, This is not preferable because it is difficult to melt and form by cross-linking of the coalescence.

  The addition timing of the catalyst is not particularly limited, and it may be added at the beginning of the reaction, during the reaction, or both.

  It is preferable to carry out the cyclization condensation reaction in the presence of a solvent and to use a devolatilization step in combination with the cyclization condensation reaction. In this case, a mode in which the devolatilization step is used throughout the cyclization condensation reaction and a mode in which the devolatilization step is not used over the entire cyclization condensation reaction but only in a part of the process. In the method using the devolatilization step in combination, the alcohol produced as a by-product in the condensation cyclization reaction is forcibly devolatilized and removed, so that the equilibrium of the reaction is advantageous for the production side.

  The devolatilization step refers to a step of removing volatile components such as a solvent and residual monomers and alcohol produced as a by-product by a cyclocondensation reaction leading to a lactone ring structure, if necessary under reduced pressure heating conditions. If this removal treatment is insufficient, the residual volatile components in the produced resin increase, resulting in problems such as coloration due to alteration during molding, and molding defects such as bubbles and silver streaks.

  In the case of a form in which a devolatilization step is used throughout the cyclization condensation reaction, the apparatus to be used is not particularly limited, but a devolatilization apparatus comprising a heat exchanger and a devolatilization tank in order to perform the present invention more effectively. It is preferable to use an extruder equipped with a vent, or a device in which the devolatilizer and the extruder are arranged in series, and it is more preferable to use a devolatilizer comprising a heat exchanger and a devolatilization tank or an extruder equipped with a vent. preferable.

  In the case of using a devolatilizer comprising the heat exchanger and a devolatilizer, the reaction treatment temperature is preferably in the range of 150 to 350 ° C, more preferably in the range of 200 to 300 ° C. If the reaction treatment temperature is lower than 150 ° C., the cyclization condensation reaction may be insufficient and the residual volatile content may increase. If the reaction treatment temperature is higher than 350 ° C., coloring or decomposition may occur.

  When using a devolatilizer comprising the heat exchanger and the devolatilization tank, the pressure during the reaction treatment is preferably in the range of 931 to 1.33 hPa (700 to 1 mmHg), and 798 to 66.5 hPa (600 to 50 mmHg). The range of is more preferable. When the pressure is higher than 931 hPa, there is a problem that volatile components including alcohol easily remain, and when the pressure is lower than 1.33 hPa, there is a problem that industrial implementation becomes difficult.

  When using the extruder with a vent, one or a plurality of vents may be used, but it is preferable to have a plurality of vents.

  The reaction processing temperature in the case of using the vented extruder is preferably in the range of 150 to 350 ° C, more preferably in the range of 200 to 300 ° C. When the temperature is in the range of 150 to 350 ° C., the cyclization condensation reaction is sufficiently performed, the residual volatile matter is reduced, and coloring and decomposition do not occur.

  When using the extruder with a vent, the pressure during the reaction treatment is preferably in the range of 931 to 1.33 hPa (700 to 1 mmHg), and more preferably in the range of 798 to 13.3 hPa (600 to 10 mmHg). When the pressure is in the range of 931 to 1.33 hPa (700 to 1 mmHg), volatile components including alcohol hardly remain, and the industrial implementation is easy.

  In the case of a form in which a devolatilization step is used throughout the cyclization condensation reaction, the physical properties of the lactone ring-containing polymer obtained may be deteriorated under severe heat treatment conditions as described later. It is preferable to use a catalyst for a dealcoholization reaction and under a mild condition as much as possible using an extruder with a vent.

  In the case of using the devolatilization step throughout the entire cyclization condensation reaction, preferably, the polymer (a) obtained in the polymerization step is introduced into the cyclization condensation reactor system together with the solvent. If necessary, it may be passed through the reactor system such as a vented extruder once again.

  You may perform the form used together only in a part of process, without using a devolatilization process over the whole process of cyclization condensation reaction. For example, the apparatus for producing the polymer (a) is further heated, and if necessary, a part of the devolatilization step is used together to advance the cyclization condensation reaction to some extent in advance, followed by the devolatilization step. Is a form in which a cyclization condensation reaction is simultaneously used to complete the reaction.

  In the form in which the devolatilization step is used throughout the cyclization condensation reaction described above, for example, when the polymer (a) is heat-treated at a high temperature close to 250 ° C. or higher using a twin-screw extruder. Depending on the difference in thermal history, partial decomposition or the like may occur before the cyclization condensation reaction occurs, and the physical properties of the resulting lactone ring-containing polymer may be deteriorated. Therefore, if the cyclization condensation reaction is allowed to proceed to some extent before the cyclization condensation reaction using the devolatilization step at the same time, the latter reaction conditions can be relaxed and the physical properties of the resulting lactone ring-containing polymer deteriorated. Is preferable. As a particularly preferred embodiment, the devolatilization step is started after a lapse of time from the start of the cyclization condensation reaction, that is, the hydroxyl group and the ester group present in the molecular chain of the polymer (a) obtained in the polymerization step. A form in which a cyclization condensation reaction is performed in advance to increase the cyclization condensation reaction rate to some extent and then a cyclization condensation reaction using a devolatilization step in combination is performed. Specifically, for example, a cyclization condensation reaction is allowed to proceed to a certain reaction rate in the presence of a solvent in advance using a kettle-type reactor, and then a reactor equipped with a devolatilizer, for example, a heat Preferred is a mode in which the cyclization condensation reaction is completed with a devolatilizer comprising an exchanger and a devolatilization tank, an extruder with a vent, or the like. Particularly in this form, it is more preferable that a catalyst for the cyclization condensation reaction is present.

  As described above, the hydroxyl group and ester group present in the molecular chain of the polymer (a) obtained in the polymerization step are preliminarily subjected to a cyclization condensation reaction to increase the cyclization condensation reaction rate to some extent. The method of carrying out the cyclization condensation reaction using the steps at the same time is a preferred form in obtaining a lactone ring-containing polymer in the present invention. With this form, a lactone ring-containing polymer having a higher glass transition temperature, a higher cyclization condensation reaction rate, and excellent heat resistance can be obtained. In this case, as a measure of the cyclization condensation reaction rate, the mass reduction rate between 150 to 300 ° C. in the dynamic TG measurement shown in the examples is preferably 2% or less, more preferably 1.5% or less. More preferably, it is 1% or less.

  The reactor that can be employed in the cyclization condensation reaction that is performed in advance before the cyclization condensation reaction using the devolatilization process at the same time is not particularly limited, but preferably an autoclave, a kettle reactor, a heat exchanger, and a devolatilization tank A vented extruder suitable for a cyclocondensation reaction in which a devolatilization step is simultaneously used can also be used. More preferred are autoclaves and kettle reactors. However, even when using a reactor such as an extruder with a vent, by adjusting the temperature condition, barrel condition, screw shape, screw operating condition, etc. It is possible to carry out the cyclization condensation reaction in the same state as the reaction state in the kettle reactor.

  In the case of the cyclization condensation reaction performed in advance before the cyclization condensation reaction using the devolatilization step at the same time, preferably, a mixture containing the polymer (a) obtained in the polymerization step and the solvent is used as (i). Examples thereof include a method in which a catalyst is added and subjected to a heat reaction, (ii) a method in which a heat reaction is performed without a catalyst, and a method in which the above (i) or (ii) is performed under pressure.

  The “mixture containing the polymer (a) and the solvent” introduced into the cyclization condensation reaction in the lactone cyclization condensation step may be the polymerization reaction mixture obtained in the polymerization step as it is, or once It means that a solvent suitable for the cyclocondensation reaction may be added again after removing the solvent.

  The solvent that can be re-added in the cyclization condensation reaction that is carried out in advance before the cyclization condensation reaction simultaneously used in the devolatilization step is not particularly limited, and examples thereof include aromatic hydrocarbons such as toluene, xylene, and ethylbenzene; Ketones such as methyl ethyl ketone and methyl isobutyl ketone; chloroform, DMSO, tetrahydrofuran and the like may be used, but the same solvent as that used in the polymerization step is preferable.

  Examples of the catalyst to be added in the above method (i) include commonly used esterification catalysts such as p-toluenesulfonic acid or transesterification catalysts, basic compounds, organic carboxylates, and carbonates. Is preferably the above-described organophosphorus compound. The addition timing of the catalyst is not particularly limited, and it may be added at the beginning of the reaction, during the reaction, or both. The amount of the catalyst to be added is not particularly limited, but is preferably 0.001 to 5% by mass, more preferably 0.01 to 2.5% by mass, and still more preferably 0.01% with respect to the mass of the polymer (a). -1% by mass, particularly preferably 0.05-0.5% by mass. The heating temperature and heating time of method (i) are not particularly limited, but the heating temperature is preferably room temperature or higher, more preferably 50 ° C. or higher, and the heating time is preferably 1 to 20 hours, more preferably 2 to 10 hours. If the heating temperature is low or the heating time is short, the cyclization condensation reaction rate is lowered, which is not preferable. Further, if the heating time is too long, the resin may be colored or decomposed, which is not preferable.

  Examples of the method (ii) include a method of heating the polymerization reaction mixture obtained in the polymerization step as it is using a pressure-resistant kettle or the like. The heating temperature is preferably 100 ° C. or higher, more preferably 150 ° C. or higher. The heating time is preferably 1 to 20 hours, more preferably 2 to 10 hours. If the heating temperature is low or the heating time is short, the cyclization condensation reaction rate is lowered, which is not preferable. Further, if the heating time is too long, the resin may be colored or decomposed, which is not preferable.

  Both the above methods (i) and (ii) have no problem even under pressure depending on conditions.

  In the case of the cyclization condensation reaction performed in advance before the cyclization condensation reaction using the devolatilization step at the same time, there is no problem even if part of the solvent volatilizes spontaneously during the reaction.

  The mass reduction rate between 150 and 300 ° C. in the dynamic TG measurement at the end of the cyclization condensation reaction performed in advance before the cyclization condensation reaction simultaneously using the devolatilization step, that is, immediately before the start of the devolatilization step is 2% or less is preferable, More preferably, it is 1.5% or less, More preferably, it is 1% or less. When the mass reduction rate is higher than 2%, the cyclization condensation reaction rate does not rise to a sufficiently high level even if the cyclization condensation reaction is performed simultaneously with the devolatilization step, and the physical properties of the resulting lactone ring-containing polymer. May decrease. In addition, when performing said cyclization condensation reaction, in addition to a polymer (a), you may coexist other thermoplastic resins.

  The hydroxyl group and ester group present in the molecular chain of the polymer (a) obtained in the polymerization step were subjected to a cyclization condensation reaction in advance to increase the cyclization condensation reaction rate to some extent, and then the devolatilization step was simultaneously used in combination. In the case of a form in which a cyclization condensation reaction is performed, a polymer obtained by a cyclization condensation reaction performed in advance (a polymer in which at least a part of a hydroxyl group and an ester group present in a molecular chain are subjected to a cyclization condensation reaction) and a solvent, The devolatilization step may be used as it is, and may be introduced into the cyclization condensation reaction. If necessary, the polymer (at least part of the hydroxyl group and ester group present in the molecular chain is subjected to cyclization condensation reaction). You may introduce | transduce into the cyclocondensation reaction which used the devolatilization process together after passing through other processes, such as adding a solvent again after isolating a compound.

  The devolatilization step is not limited to being completed at the same time as the cyclization condensation reaction, and may be completed after a lapse of time from the completion of the cyclization condensation reaction.

  The acrylic polymer having a lactone ring structure has a weight average molecular weight of preferably 1,000 to 1,000,000, more preferably 5,000 to 500,000, and particularly preferably 10,000 to 200,000. is there.

  The acrylic polymer having a lactone ring structure preferably has a mass reduction rate of 150% to 300 ° C. in dynamic TG measurement of 1% or less, more preferably 0.5% or less, and still more preferably 0. .3% or less.

  Since the acrylic polymer having a lactone ring structure has a high cyclization condensation reaction rate, it is possible to avoid the disadvantage that bubbles and silver streaks enter the molded product after molding. Furthermore, since the lactone ring structure is sufficiently introduced into the polymer due to a high cyclization condensation reaction rate, the resulting acrylic polymer having the lactone ring structure has the effects of the present invention.

  The acrylic polymer having a lactone ring structure preferably has a coloring degree (YI) in a 15% by mass chloroform solution of 6 or less, more preferably 3 or less, still more preferably 2 or less, and most preferably 1 It is as follows. If the coloring degree (YI) exceeds 6, transparency may be impaired due to coloring, and it may not be used for the intended purpose.

  The acrylic polymer having a lactone ring structure preferably has a 5% mass reduction temperature in thermogravimetric analysis (TG) of 280 ° C. or higher, more preferably 290 ° C. or higher, and further preferably 300 ° C. or higher. The 5% mass reduction temperature in thermogravimetric analysis (TG) is an index of thermal stability, and if it is less than 280 ° C., sufficient thermal stability may not be exhibited.

  The acrylic polymer having a lactone ring structure has a glass transition temperature (Tg) of preferably 115 ° C. or higher, more preferably 125 ° C. or higher, further preferably 130 ° C. or higher, more preferably 135 ° C. or higher, and most preferably 140 ° C. It is above ℃.

  The total amount of residual volatile components contained in the acrylic polymer having a lactone ring structure is preferably 5000 ppm or less, more preferably 2000 ppm or less. If the total amount of residual volatile components is more than 5000 ppm, it may be colored due to alteration during molding, foaming, or molding defects such as silver streak.

  The acrylic polymer having a lactone ring structure has a total light transmittance measured by a method according to ASTM-D-1003 of a molded product obtained by injection molding, preferably 85% or more, more preferably 88%. More preferably, it is 90% or more. The total light transmittance is a measure of transparency, and if it is less than 85%, the transparency is lowered and there is a possibility that it cannot be used for the intended purpose.

<Cellulose ester resin>
The cellulose ester resin used in the present invention is preferably a lower fatty acid ester of cellulose. The lower fatty acid in the lower fatty acid ester of cellulose means a fatty acid having 6 or less carbon atoms. For example, cellulose acetate, cellulose propionate, cellulose butyrate and the like, and JP-A Nos. 10-45804 and 8-231761 , Mixed fatty acid esters such as cellulose acetate propionate and cellulose acetate butyrate as described in US Pat. No. 2,319,052 can be used. Among the above description, the lower fatty acid ester of cellulose particularly preferably used is cellulose acetate propionate or cellulose acetate butyrate. Particularly preferred is cellulose acetate propionate, and these cellulose esters can be used alone or in combination.

  If the molecular weight of cellulose acetate propionate or cellulose acetate butyrate is too small, the brittleness will decrease, and if the molecular weight is too high, the viscosity of the acrylic resin composition will become too high and the productivity will decrease. Cellulose acetate propionate or cellulose acetate butyrate has a weight average molecular weight (Mw) of preferably 70,000 to 250,000, more preferably 100,000 to 200,000.

  The measurement conditions 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 = 1,000,000 to 500 calibration curves with 13 samples were used. The 13 samples are preferably used at approximately equal intervals.

  Cellulose acetate propionate or cellulose acetate butyrate has an acyl group having 2 to 4 carbon atoms as a substituent, and the total substitution degree (T) of the acyl group is 2.00 to 2.99, and is an acetyl group. The substitution degree (ac) is 0.10 to 1.89, the propionyl group substitution degree (p) is 1.10 to 2.89, or the butyryl group substitution degree (b) is 1.10 to 2.89. preferable.

  The portion that is not substituted with an acyl group usually exists as a hydroxyl group. These can be synthesized by known methods. In addition, the substitution degree of an acetyl group and the substitution degree of other acyl groups are obtained by a method prescribed in ASTM-D817-96.

  As the cellulose ester, a cellulose ester synthesized using cotton linter, wood pulp, kenaf or the like as a raw material can be used alone or in combination. In particular, it is preferable to use a cellulose ester synthesized from cotton linter (hereinafter sometimes simply referred to as linter) alone or in combination.

<Antioxidant>
Since the cellulose ester that is one of the substrates of the optical film of the present invention is accelerated not only by heat but also by oxygen, the optical film of the present invention can also contain an antioxidant as a stabilizer. .

  In a high temperature environment, the film molding material is preferably decomposed by heat and oxygen, and therefore preferably contains an antioxidant.

  Moreover, it is also preferable to wash | clean the cellulose ester of a preferable aspect in this invention in antioxidant presence at the time of suspension washing by a poor solvent. The antioxidant to be used is not limited as long as it is a compound that inactivates radicals generated in the cellulose ester or suppresses deterioration of the cellulose ester caused by addition of oxygen to the radical generated in the cellulose ester. be able to.

  The antioxidant used for suspension washing of the cellulose ester may remain in the cellulose ester after washing. The remaining amount is preferably 0.01 to 2000 ppm, more preferably 0.05 to 1000 ppm. More preferably, it is 0.1-100 ppm.

  The antioxidant useful in the present invention can be used without limitation as long as it is a compound that suppresses the deterioration of the film molding material due to oxygen. Among the useful antioxidants, phenolic compounds, hindered amine compounds, Phosphorus compounds, sulfur compounds, acrylate compounds, benzofuranone compounds, oxygen scavengers and the like can be mentioned. Of these, phenol compounds, phosphorus compounds, acrylate compounds, and benzofuranone compounds are particularly preferable. By blending these compounds, it is possible to prevent coloring and strength reduction of the molded product due to heat, thermal oxidation degradation, and the like without reducing transparency, heat resistance, and the like. These antioxidants can be used alone or in combination of two or more.

<Acrylic fine particles>
In the optical film of the present invention, acrylic particles can be added to impart toughness to the film with almost no decrease in thermal resistance such as tension softening point.

  Preferable acrylic fine particles are not particularly limited, but are preferably acrylic fine particles having a layer structure of two or more layers, and particularly preferably the following multilayer structure acrylic granular composite.

  The multilayer structure acrylic granular composite is formed by laminating the innermost hard layer polymer, the cross-linked soft layer polymer exhibiting rubber elasticity, and the outermost hard layer polymer from the central portion toward the outer peripheral portion. It refers to a particulate acrylic polymer having a structure. Preferred embodiments of the multilayer structure acrylic granular composite used in the acrylic resin composition of the present invention include the following. (A) Monomer comprising 80 to 98.9% by mass of methyl methacrylate, 1 to 20% by mass of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group, and 0.01 to 0.3% by mass of polyfunctional grafting agent An innermost hard layer polymer obtained by polymerizing the body mixture, (b) in the presence of the innermost hard layer polymer, 75 to 98.5% by mass of an alkyl acrylate having an alkyl group with 4 to 8 carbon atoms, A crosslinked soft layer polymer obtained by polymerizing a monomer mixture composed of 0.01 to 5% by mass of a multifunctional crosslinking agent and 0.5 to 5% by mass of a multifunctional grafting agent, (c) the innermost hard In the presence of a polymer comprising a layer and a crosslinked soft layer, a monomer mixture composed of 80 to 99% by mass of methyl methacrylate and 1 to 20% by mass of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group is polymerized. Outermost hard layer polymer obtained by And the obtained three-layer structure polymer is the innermost hard layer polymer (a) 5 to 40% by mass, the soft layer polymer (b) 30 to 60% by mass, and the outermost layer polymer. A hard layer polymer (c) comprising 20 to 50% by mass, having an insoluble part when fractionated with acetone, and an acrylic granular composite having a methyl ethyl ketone swelling degree of 1.5 to 4.0 in the insoluble part, Can be mentioned.

  In addition, as disclosed in JP-B-60-17406 or JP-B-3-39095, not only the composition and particle diameter of each layer of the multilayer structure acrylic granular composite are defined, but also the multilayer structure acrylic granular composite By setting the tensile elastic modulus and the degree of swelling of methyl ethyl ketone in the acetone-insoluble part within a specific range, it is possible to realize a further sufficient balance between impact resistance and stress whitening resistance.

  Here, the innermost hard layer polymer (a) constituting the multi-layer structure acrylic granular composite is 80 to 98.9% by mass of methyl methacrylate and 1 to 20% of alkyl acrylate having 1 to 8 carbon atoms in the alkyl group. % And a polyfunctional grafting agent obtained by polymerizing a monomer mixture consisting of 0.01 to 0.3% by mass. Here, examples of the alkyl acrylate having 1 to 8 carbon atoms in the alkyl group include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, s-butyl acrylate, 2-ethylhexyl acrylate, and the like. And n-butyl acrylate are preferably used. The proportion of the alkyl acrylate unit in the innermost hard layer polymer (a) is 1 to 20% by mass. When the unit is less than 1% by mass, the thermal decomposability of the polymer is increased, while the unit is 20% by mass. If it exceeds 50%, the glass transition temperature of the innermost hard layer polymer (c) is lowered, and the impact resistance imparting effect of the three-layer structure acrylic granular composite is lowered.

  Examples of the polyfunctional grafting agent include polyfunctional monomers having different polymerizable functional groups, such as allyl esters of acrylic acid, methacrylic acid, maleic acid, and fumaric acid, and allyl methacrylate is preferably used. . The polyfunctional grafting agent is used to chemically bond the innermost hard layer polymer and the soft layer polymer, and the ratio used during the innermost hard layer polymerization is 0.01 to 0.3% by mass. . If the ratio of the unit is out of this range, the impact resistance imparting effect of the three-layer structure acrylic polymer is lowered, which is not preferable.

  The crosslinked soft layer polymer (b) constituting the acrylic granular composite is an alkyl acrylate 75-98.5 having 1 to 8 carbon atoms in the presence of the innermost hard layer polymer (a). What is obtained by polymerizing a monomer mixture consisting of mass%, polyfunctional crosslinking agent 0.01 to 5 mass% and polyfunctional grafting agent 0.5 to 5 mass% is preferable. Here, as the alkyl acrylate having 4 to 8 carbon atoms in the alkyl group, n-butyl acrylate or 2-ethylhexyl acrylate is preferably used. In addition to these polymerizable monomers, it is possible to copolymerize 25% by mass or less of other monofunctional monomers capable of copolymerization. Examples of other monofunctional monomers that can be copolymerized include styrene and substituted styrene derivatives. As the ratio of the alkyl acrylate having 4 to 8 carbon atoms in the alkyl group and styrene increases, the glass transition temperature of the produced polymer (b) decreases as the former increases, that is, it can be softened. On the other hand, from the viewpoint of the transparency of the resin assembly, the refractive index of the soft layer polymer (b) at room temperature is set to the innermost hard layer polymer (a), the outermost hard layer polymer (c), and the hard heat. It is more advantageous to make it closer to the plastic acrylic resin, and the ratio between the two is selected in consideration of these. For example, in applications where the coating layer thickness is small, it is not always necessary to copolymerize styrene.

  As the polyfunctional grafting agent, those mentioned in the item of the innermost layer hard polymer (a) can be used. The polyfunctional grafting agent used here is used to chemically bond the soft layer polymer (b) and the outermost hard layer polymer (c), and the ratio used during the innermost hard layer polymerization is 0.00. 5-5 mass% is preferable. If the ratio of the unit is out of this range, the impact resistance imparting effect of the three-layer structure acrylic polymer is lowered, which is not preferable.

  As the polyfunctional crosslinking agent, generally known crosslinking agents such as divinyl compounds, diallyl compounds, diacrylic compounds, and dimethacrylic compounds can be used, but polyethylene glycol diacrylate (molecular weight 200 to 600) is preferably used. The polyfunctional cross-linking agent used here is used to generate a cross-linked structure at the time of polymerization of the soft layer (b) and develop an effect of imparting impact resistance. However, if the above-mentioned polyfunctional grafting agent is used during the polymerization of the soft layer, the polyfunctional crosslinking agent is not an essential component because the crosslinked structure of the soft layer (b) is generated to some extent. Is preferably 0.01 to 5% by mass in the soft layer polymerization. If the proportion of the unit exceeds 5% by mass, the impact resistance imparting effect of the three-layer structure acrylic polymer is lowered, which is not preferable.

  In the presence of the innermost hard layer polymer (a) and the soft layer polymer (b), the outermost hard layer polymer (c) constituting the multilayer structure acrylic granular composite is 80 to 99 mass% of methyl methacrylate. % And a monomer mixture comprising 1 to 20% by mass of an alkyl acrylate having 1 to 8 carbon atoms in the alkyl group is preferred. Here, as the acrylic alkylate, those described above are used, and methyl acrylate and ethyl acrylate are preferably used. The ratio of the alkyl acrylate unit in the outermost hard layer (c) is preferably 1 to 20% by mass. If the unit is less than 1% by mass, the thermal decomposability of the polymer is increased. On the other hand, if the unit exceeds 20% by mass, the tackiness of the three-layer structure acrylic granular composite particles increases, In addition to being difficult to handle, the compatibility with the hard thermoplastic acrylic resin is reduced, so that only those having poor impact resistance and weather resistance can be obtained.

  Also, during the polymerization of the outermost hard layer (c), for the purpose of improving the compatibility with the acrylic polymer having a lactone ring structure, an alkyl mercaptan may be used as a chain transfer agent in order to adjust the molecular weight. Is possible. In particular, it is preferable to provide the outermost hard layer with a gradient such that the molecular weight gradually decreases from the inside toward the outside in order to improve the balance between elongation and impact resistance. As a specific method, the monomer mixture for forming the outermost hard layer is divided into two or more, and the molecular weight is increased from the inside by a method of sequentially increasing the amount of chain transfer agent added each time. It is possible to make it smaller toward the outside. The molecular weight formed at this time can also be examined by polymerizing the monomer mixture used each time under the same conditions and measuring the molecular weight of the obtained polymer.

  The particle diameter of the acrylic granular composite which is a multilayer structure polymer usable in the present invention is not particularly limited, but is preferably 10 nm or more and 1000 nm or less, and more preferably 20 nm or more and 500 nm or less. More preferably, it is most preferably 50 nm or more and 400 nm or less.

  In the acrylic granular composite that is a multilayer structure polymer that can be used in the present invention, the mass ratio of the core and the shell is not particularly limited, but when the entire multilayer structure polymer is 100 parts by mass, The core layer is preferably 50 parts by mass or more and 90 parts by mass or less, and more preferably 60 parts by mass or more and 80 parts by mass or less.

  Examples of such commercially available multilayered acrylic granular composites include, for example, “Metablene” (registered trademark) manufactured by Mitsubishi Rayon Co., Ltd., “Kaneace” (registered trademark) manufactured by Kaneka Chemical Co., Ltd., Kureha Chemical Industry Co., Ltd. “Paraloid” (registered trademark) manufactured by Rohm and Haas, “Staffroid” (registered trademark) manufactured by Gantz Kasei Kogyo, and “Parapet SA” (registered trademark) manufactured by Kuraray These can be used alone or in combination of two or more.

  In addition, specific examples of the acrylic fine particles (c-1) that are graft copolymers suitably used as the acrylic fine particles that can be used in the present invention include unsaturated carboxylic acid esters in the presence of a rubbery polymer. A monomer mixture comprising a monomer, an unsaturated carboxylic acid monomer, an aromatic vinyl monomer, and, if necessary, other vinyl monomers copolymerizable therewith was copolymerized. A graft copolymer is mentioned.

  Although there is no restriction | limiting in particular in the rubbery polymer used for the acrylic microparticles | fine-particles (c-1) which is a graft copolymer, Diene rubber, acrylic rubber, ethylene rubber, etc. can be used. Specific examples include polybutadiene, styrene-butadiene copolymer, block copolymer of styrene-butadiene, acrylonitrile-butadiene copolymer, butyl acrylate-butadiene copolymer, polyisoprene, butadiene-methyl methacrylate copolymer. , Butyl acrylate-methyl methacrylate copolymer, butadiene-ethyl acrylate copolymer, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-isoprene copolymer, and ethylene-acrylic acid A methyl copolymer etc. are mentioned. These rubbery polymers can be used alone or in a mixture of two or more.

  Moreover, since the transparency of the optical film of this invention can be obtained when the refractive index of each of the acrylic polymer having a lactone ring structure and the acrylic fine particles is close, it is preferable. Specifically, the refractive index difference between the acrylic fine particles and the acrylic polymer having a lactone ring structure is preferably 0.05 or less, more preferably 0.02 or less, and particularly preferably 0.01 or less. . In order to satisfy such a refractive index condition, a method for adjusting the composition ratio of each monomer unit of an acrylic polymer having a lactone ring structure and / or a rubbery polymer or a single amount used for acrylic fine particles By the method of adjusting the composition ratio of the body, the refractive index difference can be reduced, and an optical film excellent in transparency can be obtained.

  Here, the difference in refractive index means that the optical resin film of the present invention is sufficiently dissolved under appropriate conditions in a solvent in which the acrylic polymer having a lactone ring structure is soluble, and this is centrifuged. Are separated into a solvent-soluble part and an insoluble part by purifying the soluble part (acrylic polymer having a lactone ring structure) and the insoluble part (acrylic fine particles), and then measuring the refractive index (23 (° C., measurement wavelength: 550 nm).

  In the present invention, the method for blending the acrylic fine particles with the acrylic polymer having the lactone ring structure is not particularly limited, and the acrylic polymer having the lactone ring structure and the cellulose ester are prepared by dispersing the acrylic fine particles in advance. A method in which a resin is dissolved in a solution (dope solution) and mixed, or a method in which an acrylic fine particle and other optional additives are dissolved and mixed and added in-line is preferably used. Also, after blending in advance an acrylic polymer having a lactone ring structure and other optional components, a method of uniformly melting and kneading with a single-screw or twin-screw extruder is usually used at 200 to 350 ° C. while adding acrylic fine particles. be able to.

<Ultraviolet absorber>
An ultraviolet absorber can also be added to the optical film of the present invention.

  The ultraviolet absorber is excellent in the ability to absorb ultraviolet rays having a wavelength of 370 nm or less from the viewpoint of preventing deterioration of the polarizer and the display device with respect to ultraviolet rays, and has little absorption of visible light having a wavelength of 400 nm or more from the viewpoint of liquid crystal display properties. Those are preferred. Examples of the ultraviolet absorber used in the present invention include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, triazine compounds, and the like. However, benzophenone compounds, less colored benzotriazole compounds, and triazine compounds are preferable. Further, ultraviolet absorbers described in JP-A Nos. 10-182621 and 8-337574, and polymer ultraviolet absorbers described in JP-A Nos. 6-148430 and 2003-113317 may be used.

  Specific examples of the benzotriazole ultraviolet absorber include 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) benzo Triazole, 2- (2'-hydroxy-3'-tert-butyl-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-di-tert-butylphenyl) -5 Chlorobenzotriazole, 2- (2′-hydroxy-3 ′-(3 ″, 4 ″, 5 ″, 6 ″ -tetrahydrophthalimidomethyl) -5′-methylphenyl) benzotriazole, 2,2-methylenebis (4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol), 2- (2'-hydroxy- '-Tert-butyl-5'-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3'-tert-butyl-5'-(2-octyloxycarbonylethyl) -phenyl) -5 -Chlorobenzotriazole, 2- (2'-hydroxy-3 '-(1-methyl-1-phenylethyl) -5'-(1,1,3,3-tetramethylbutyl) -phenyl) benzotriazole, 2 -(2H-benzotriazol-2-yl) -6- (linear and side chain dodecyl) -4-methylphenol, octyl-3- [3-tert-butyl-4-hydroxy-5- (chloro-2H- Benzotriazol-2-yl) phenyl] propionate and 2-ethylhexyl-3- [3-tert-butyl-4-hydroxy-5- (5-chloro-2) - can be exemplified mixtures of benzotriazol-2-yl) phenyl] propionate, and the like.

  As commercially available products, TINUVIN 171, TINUVIN 900, TINUVIN 928, TINUVIN 360 (all manufactured by Ciba Japan), LA31 (manufactured by ADEKA), RUVA-100 ( Otsuka Chemical).

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

  In the present invention, the ultraviolet absorber is preferably added in an amount of 0.1 to 5% by mass, more preferably 0.2 to 3% by mass, and further 0.5 to 2% by mass based on the cellulose ester. It is preferable to do. Two or more of these may be used in combination.

  The benzotriazole structure or triazine structure may be part of the polymer or regularly pendant to the polymer, and part of the molecular structure of other additives such as plasticizers, antioxidants, acid scavengers, etc. May be introduced.

  Although it does not specifically limit as a conventionally well-known ultraviolet absorptive polymer, For example, the polymer which homopolymerized RUVA-93 (made by Otsuka Chemical), the polymer which copolymerized RUVA-93, and another monomer, etc. are mentioned. . Specific examples include PUVA-30M obtained by copolymerization of RUVA-93 and methyl methacrylate at a ratio (mass ratio) of 3: 7, and PUVA-50M obtained by copolymerization at a ratio of 5: 5 (mass ratio). It is done. Furthermore, the polymer etc. which are described in Unexamined-Japanese-Patent No. 2003-113317 are mentioned.

<Plasticizer>
A plasticizer can also be added in the production of the optical film of the present invention.

  The plasticizer is an additive having an effect of improving brittleness or imparting flexibility by adding it to a polymer.

  The optical film of the present invention preferably contains 1 to 25% by mass of a plasticizer. More preferably, the plasticizer is contained in an amount of 3 to 20% by mass, and more preferably 5 to 15% by mass.

  In the present invention, an ester plasticizer composed of a polyhydric alcohol and a monovalent carboxylic acid, and an ester plasticizer composed of a polyvalent carboxylic acid and a monovalent alcohol have a high affinity with the cellulose ester and are preferred.

  Examples of the polyhydric alcohol that is a raw material of the ester plasticizer preferably used in the present invention include the following, but the present invention is not limited thereto. Adonitol, arabitol, ethylene glycol, glycerin, diglycerin, diethylene glycol, triethylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, dipropylene glycol, tripropylene glycol, 1,2-butanediol 1,3-butanediol, 1,4-butanediol, dibutylene glycol, 1,2,4-butanetriol, 1,5-pentanediol, 1,6-hexanediol, hexanetriol, galactitol, mannitol, 3-methylpentane-1,3,5-triol, pinacol, sorbitol, trimethylolpropane, ditrimethylolpropane, trimethylolethane, pentaethysitol, dipentaerythritol, xylene Mention may be made of the toll and the like. In particular, ethylene glycol, glycerin, and trimethylolpropane are preferable.

  Specific examples of ethylene glycol ester plasticizers that are one of the polyhydric alcohol esters include ethylene glycol alkyl ester plasticizers such as ethylene glycol diacetate and ethylene glycol dibutyrate, and ethylene glycol dicyclopropyl. Examples thereof include ethylene glycol cycloalkyl ester plasticizers such as carboxylate and ethylene glycol dicyclohexylcarboxylate, and ethylene glycol aryl ester plasticizers such as ethylene glycol dibenzoate and ethylene glycol di4-methylbenzoate. These alkylate groups, cycloalkylate groups, and arylate groups may be the same or different, and may be further substituted. Further, it may be a mix of alkylate group, cycloalkylate group and arylate group, and these substituents may be covalently bonded. Further, the ethylene glycol part may be substituted, the ethylene glycol ester partial structure may be part of the polymer or regularly pendant, and may be an antioxidant, an acid scavenger, an ultraviolet absorber, etc. It may be introduced into a part of the molecular structure of the additive.

  Specific examples of the glycerin ester plasticizer that is one of the polyhydric alcohol esters include glycerol alkyl esters such as triacetin, tributyrin, glycerol diacetate caprylate, glycerol oleate propionate, and glycerol tricyclopropylcarboxylate. Glycerol glycerol esters such as glycerol tricyclohexyl carboxylate, glycerol aryl esters such as glycerol tribenzoate and glycerol 4-methylbenzoate, diglycerol tetraacetylate, diglycerol tetrapropionate, diglycerol acetate tricaprylate, diglycerol Tetralaurate, diglycerin alkyl ester, diglycerin tetracyclobutylcarboxylate, diglycerin tet Diglycerol cycloalkyl esters such as cyclopentyl carboxylate, diglycerin tetrabenzoate, diglycerin aryl ester such as diglycerin 3-methylbenzoate or the like. These alkylate groups, cycloalkylcarboxylate groups, and arylate groups may be the same or different, and may be further substituted. Further, it may be a mixture of alkylate group, cycloalkylcarboxylate group, and arylate group, and these substituents may be bonded by a covalent bond. Furthermore, the glycerin and diglycerin part may be substituted, the partial structure of the glycerin ester and the diglycerin ester may be part of the polymer or regularly pendant, and the antioxidant, acid scavenger, You may introduce | transduce into a part of molecular structure of additives, such as a ultraviolet absorber.

  Specific examples of other polyhydric alcohol ester plasticizers include polyhydric alcohol ester plasticizers described in paragraphs 30 to 33 of JP-A No. 2003-12823.

  These alkylate groups, cycloalkylcarboxylate groups, and arylate groups may be the same or different, and may be further substituted. Further, it may be a mixture of alkylate group, cycloalkylcarboxylate group, and arylate group, and these substituents may be bonded by a covalent bond. Furthermore, the polyhydric alcohol part may be substituted, and the partial structure of the polyhydric alcohol may be part of the polymer or regularly pendant, and may be an antioxidant, an acid scavenger, an ultraviolet absorber. May be introduced into a part of the molecular structure of the additive.

  Among the ester plasticizers composed of the polyhydric alcohol and the monovalent carboxylic acid, alkyl polyhydric alcohol aryl esters are preferred. Specifically, the above-mentioned ethylene glycol dibenzoate, glycerin tribenzoate, diglycerin tetrabenzoate, Exemplified compound 16 described in paragraph 31 of JP2003-12823A can be mentioned.

  Specific examples of the dicarboxylic acid ester plasticizer that is one of the polyvalent carboxylic acid esters include alkyl dicarboxylic acid alkyl ester plasticizers such as didodecyl malonate, dioctyl adipate, and dibutyl sebacate. Alkyl dicarboxylic acid cycloalkyl ester type plasticizers such as cyclopentyl succinate and dicyclohexyl adipate, alkyl dicarboxylic acid aryl ester type plasticizers such as diphenyl succinate and di4-methylphenyl glutarate, dihexyl-1,4-cyclohexane Cycloalkyl dicarboxylic acid alkyl ester plasticizers such as dicarboxylate and didecylbicyclo [2.2.1] heptane-2,3-dicarboxylate, dicyclohexyl-1,2-cyclobutanedicarboxylate, dicis Cycloalkyldicarboxylic acid cycloalkyl ester plasticizers such as ropropyl-1,2-cyclohexyldicarboxylate, diphenyl-1,1-cyclopropyldicarboxylate, di2-naphthyl-1,4-cyclohexanedicarboxylate, etc. Cycloalkyldicarboxylic acid aryl ester plasticizer, diethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, and other aryl dicarboxylic acid alkyl ester plasticizers, dicyclopropyl phthalate, dicyclohexyl phthalate, etc. Aryl dicarboxylic acid cycloalkyl ester plasticizers, and aryl dicarboxylic acid aryl ester plasticizers such as diphenyl phthalate and di-4-methylphenyl phthalate And the like. These alkoxy groups and cycloalkoxy groups may be the same or different, may be mono-substituted, and these substituents may be further substituted. The alkyl group and cycloalkyl group may be mixed, and these substituents may be bonded together by a covalent bond. Furthermore, the aromatic ring of phthalic acid may be substituted, and a multimer such as a dimer, trimer or tetramer may be used. In addition, the partial structure of phthalate ester may be part of the polymer or regularly pendant to the polymer, and may be part of the molecular structure of additives such as antioxidants, acid scavengers, and UV absorbers. It may be introduced.

  Examples of other polycarboxylic acid ester plasticizers include alkyl polycarboxylic acid alkyl esters such as tridodecyl tricarbarate and tributyl-meso-butane-1,2,3,4-tetracarboxylate. Plasticizers, alkylpolycarboxylic acid cycloalkyl ester plasticizers such as tricyclohexyltricarbarate, tricyclopropyl-2-hydroxy-1,2,3-propanetricarboxylate, triphenyl 2-hydroxy- Alkyl polyvalent carboxylic acid aryl ester plasticizers such as 1,2,3-propanetricarboxylate, tetra-3-methylphenyltetrahydrofuran-2,3,4,5-tetracarboxylate, tetrahexyl-1,2, 3,4-cyclobutanetetracarboxylate, tetrabu Cycloalkyl polycarboxylic acid alkyl ester plasticizers such as ru-1,2,3,4-cyclopentanetetracarboxylate, tetracyclopropyl-1,2,3,4-cyclobutanetetracarboxylate, tricyclohexyl- Cycloalkyl polycarboxylic acid cycloalkyl ester plasticizers such as 1,3,5-cyclohexyl tricarboxylate, triphenyl-1,3,5-cyclohexyl tricarboxylate, hexa-4-methylphenyl-1,2, Cycloalkyl polycarboxylic acid aryl ester plasticizers such as 3,4,5,6-cyclohexylhexacarboxylate, tridodecylbenzene-1,2,4-tricarboxylate, tetraoctylbenzene-1,2,4 , 5-tetracarboxylate and other aryl polyvalent Rubinoic acid alkyl ester plasticizers, tricyclopentylbenzene-1,3,5-tricarboxylate, tetracyclohexylbenzene-1,2,3,5-tetracarboxylate and other aryl polyvalent carboxylic acid cycloalkyl esters Plasticizers of aryl polyvalent carboxylic acid aryl esters such as plasticizers triphenylbenzene-1,3,5-tetracarboxylate, hexa-4-methylphenylbenzene-1,2,3,4,5,6-hexacarboxylate Agents. These alkoxy groups and cycloalkoxy groups may be the same or different, and may be monosubstituted, and these substituents may be further substituted. The alkyl group and cycloalkyl group may be mixed, and these substituents may be bonded together by a covalent bond. Furthermore, the aromatic ring of phthalic acid may be substituted, and a multimer such as a dimer, trimer or tetramer may be used. In addition, the partial structure of phthalate ester may be part of the polymer or may be regularly pendant to the polymer, and introduced into part of the molecular structure of additives such as antioxidants, acid scavengers, UV absorbers, etc. May be.

  Among the ester plasticizers composed of the polyvalent carboxylic acid and the monohydric alcohol, alkyl dicarboxylic acid alkyl esters are preferable, and specific examples include the dioctyl adipate.

  Other plasticizers preferably used in the present invention include carbohydrate ester plasticizers and polymer plasticizers.

  Next, the carbohydrate ester plasticizer will be described. The carbohydrate means a monosaccharide, disaccharide or trisaccharide in which the saccharide is present in the form of pyranose or furanose (6-membered ring or 5-membered ring). Non-limiting examples of carbohydrates include glucose, saccharose, lactose, cellobiose, mannose, xylose, ribose, galactose, arabinose, fructose, sorbose, cellotriose and raffinose. The carbohydrate ester refers to a compound in which a hydroxyl group of a carbohydrate and a carboxylic acid are dehydrated and condensed to form an ester compound, and specifically means an aliphatic carboxylic acid ester or an aromatic carboxylic acid ester of a carbohydrate. Examples of the aliphatic carboxylic acid include acetic acid and propionic acid, and examples of the aromatic carboxylic acid include benzoic acid, toluic acid, and anisic acid. Carbohydrates have a number of hydroxyl groups depending on the type, but even if a part of the hydroxyl group reacts with the carboxylic acid to form an ester compound, the whole hydroxyl group reacts with the carboxylic acid to form an ester compound. Also good. In the present invention, it is preferable that all of the hydroxyl groups react with the carboxylic acid to form an ester compound.

  Specific examples of the carbohydrate ester plasticizer include glucose pentaacetate, glucose pentapropionate, glucose pentabtylate, saccharose octaacetate, and saccharose octabenzoate. Among these, saccharose octabenzoate is more preferable. preferable.

  Examples of these compounds are listed below, but the present invention is not limited thereto.

Monopet SB: manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Monopet SOA: manufactured by Daiichi Kogyo Seiyaku Co., Ltd. Specific examples of the polymer plasticizer include aliphatic hydrocarbon polymers, alicyclic hydrocarbon polymers, and ethyl polyacrylate. Acrylic polymers such as polymethyl methacrylate, copolymers of methyl methacrylate and 2-hydroxyethyl methacrylate, copolymers of methyl acrylate, methyl methacrylate and 2-hydroxyethyl methacrylate, polyvinyl Vinyl polymers such as isobutyl ether and poly N-vinyl pyrrolidone, styrene polymers such as polystyrene and poly 4-hydroxystyrene, polyesters such as polybutylene succinate, polyethylene terephthalate and polyethylene naphthalate, and polymers such as polyethylene oxide and polypropylene oxide Ether, polyamides, polyurethanes, polyureas and the like. The number average molecular weight is preferably about 1,000 to 500,000, particularly preferably 5,000 to 200,000. These polymer plasticizers may be a homopolymer composed of one type of repeating unit or a copolymer having a plurality of repeating structures. Two or more of the above polymers may be used in combination.

  The amount of the other plasticizer added is usually 0.1 to 50 parts by weight, preferably 1 to 30 parts by weight, more preferably 3 to 100 parts by weight of the acrylic polymer having a lactone ring structure and 100 parts by weight of the cellulose ester resin. -15 parts by mass.

  The optical film of the present invention preferably contains 1 to 25% by mass of an ester plasticizer comprising a polyhydric alcohol and a monovalent carboxylic acid, and an ester plasticizer comprising a polyvalent carboxylic acid and a monohydric alcohol. , And may be used in combination with other plasticizers.

  In the optical film of the present invention, an ester plasticizer comprising a polyhydric alcohol and a monovalent carboxylic acid is more preferred, and an ester plasticizer comprising a trivalent or higher alcohol and a monovalent carboxylic acid is compatible with the cellulose ester. Because it is high and can be added at a high addition rate, bleed-out does not occur even when other plasticizers and additives are used in combination, and other types of plasticizers and additives can be added as necessary. It is most preferable because it can be easily used together.

  In addition, since the optical film of this invention will affect as an optical use when it colors, Preferably yellow degree (yellow index, YI) is 3.0 or less, More preferably, it is 1.0 or less. Yellowness can be measured based on JIS-K7103.

<Matting agent>
A matting agent can be added to the optical film of the present invention in order to impart slipperiness, optical and mechanical functions. Examples of the matting agent include inorganic compound fine particles and organic compound fine particles.

  The shape of the matting agent is preferably a spherical shape, a rod shape, a needle shape, a layer shape, a flat shape or the like. Examples of the matting agent include silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, calcium carbonate, kaolin, talc, calcined calcium silicate, hydrated calcium silicate, aluminum silicate, magnesium silicate, and calcium phosphate. Examples thereof include inorganic fine particles such as oxides, phosphates, silicates, and carbonates, and crosslinked polymer fine particles. Among these, silicon dioxide is preferable because it can reduce the haze of the film. These fine particles are preferably surface-treated with an organic substance because the haze of the film can be reduced.

  The surface treatment is preferably performed with halosilanes, alkoxysilanes, silazane, siloxane, or the like. The larger the average particle size of the fine particles, the greater the sliding effect, and the smaller the average particle size, the better the transparency. The average primary particle size of the fine particles is in the range of 0.01 to 1.0 μm. The average particle diameter of primary particles of preferable fine particles is preferably 5 to 50 nm, and more preferably 7 to 14 nm. These fine particles are preferably used for generating irregularities of 0.01 to 1.0 μm on the surface of the cellulose ester film.

  As the fine particles of silicon dioxide, Aerosil 200, 200V, 300, R972, R972V, R974, R202, R812, OX50, TT600, NAX50, etc. manufactured by Nippon Aerosil Co., Ltd. P10, KE-P30, KE-P100, KE-P150 and the like can be mentioned, and Aerosil 200V, R972V, NAX50, KE-P30 and KE-P100 are preferable. Two or more kinds of these fine particles may be used in combination.

  When using 2 or more types together, it can mix and use in arbitrary ratios. Fine particles having different average particle sizes and materials, for example, Aerosil 200V and R972V can be used in a mass ratio of 0.1: 99.9 to 99.9: 0.1.

  These matting agents are preferably added by kneading. In another form, after mixing and dispersing a matting agent dispersed in a solvent in advance, an acrylic polymer having a lactone ring structure, a cellulose ester and / or a plasticizer and / or an antioxidant and / or an ultraviolet absorber. From the viewpoint of obtaining a solid material obtained by volatilizing or precipitating the solvent and using it in the cellulose ester production process, the matting agent can be uniformly dispersed in the cellulose ester.

  The matting agent can also be added to improve the mechanical, electrical and optical properties of the film.

  In addition, although the slipperiness of the film obtained improves, so that these microparticles | fine-particles are added, since a haze raises so that it adds, content is preferably with respect to the acrylic polymer and cellulose ester which have a lactone ring structure. 0.001-5 mass% is preferable, More preferably, it is 0.005-1 mass%, More preferably, it is 0.01-0.5 mass%.

  As the optical film of the present invention, if the haze value exceeds 1.0%, the optical material is affected. Therefore, the haze value is preferably less than 1.0%, more preferably less than 0.5%. . The haze value can be measured based on JIS-K7136.

  The film constituent material is required to have little or no volatile component in the film forming process. This is for foaming during heating to reduce or avoid defects inside the film and flatness deterioration of the film surface.

  Desirably, the content of volatile components in the film constituting material is 1% by mass or less, preferably 0.5% by mass or less, more preferably 0.2% by mass or less, and still more preferably 0.1% by mass or less. It is. In the present invention, a heat loss from 30 ° C. to 250 ° C. is determined using a differential thermogravimetric measuring device (TG / DTA200 manufactured by Seiko Denshi Kogyo Co., Ltd.), and the amount is defined as the content of volatile components.

  It is preferable that the film constituent material used removes volatile components typified by the moisture and the solvent before film formation or during heating. A known drying method can be applied to the removal method, and it can be performed by a method such as a heating method, a reduced pressure method, a heated reduced pressure method, or the like, and may be performed in air or in an atmosphere in which nitrogen is selected as an inert gas. When these known drying methods are performed, it is preferable in terms of film quality to be performed in a temperature range where the film constituting material does not decompose.

  By drying before film formation, generation of volatile components can be reduced, and cellulose ester alone or at least one mixture or compatible material other than cellulose ester of cellulose ester and film constituent materials is divided. And can be dried. The drying temperature is preferably 70 ° C. or higher. When a material having a glass transition temperature is present in the material to be dried, heating to a drying temperature higher than the glass transition temperature may cause the material to melt and become difficult to handle. It is preferable that it is below the temperature. When a plurality of substances have a glass transition temperature, the glass transition temperature with the lower glass transition temperature is used as a reference. More preferably, they are 70 degreeC or more and (glass transition temperature-5) degreeC or less, More preferably, they are 110 degreeC or more and (glass transition temperature-20) degreeC or less. The drying time is preferably 0.5 to 24 hours, more preferably 1 to 18 hours, and further preferably 1.5 to 12 hours. If the drying temperature is too low, the removal rate of volatile components will be low, and it will take too much time to dry. Further, the drying process may be divided into two or more stages. For example, the drying process includes a preliminary drying process for storage of materials and a just-before drying process performed immediately before film formation to one week before film formation. Also good.

《Optical film formation》
Although the example of the film forming method of an optical film film is demonstrated, this invention is not limited to this.

  As a method for forming the optical film of the present invention, production methods such as an inflation method, a T-die method, a calendar method, a cutting method, a casting method, an emulsion method, and a hot press method can be used. From the standpoints of suppressing the optical defects such as die lines and the like, solution casting by casting is preferred.

(Organic solvent)
The organic solvent useful for forming the dope when the optical film of the present invention is produced by the solution casting method includes a lactone ring-containing acrylic polymer (A), a cellulose ester resin (B), and other additives. If it melt | dissolves simultaneously, it can be used without a restriction | limiting. For example, as the chlorinated organic solvent, methylene chloride, as the non-chlorinated organic solvent, methyl acetate, ethyl acetate, amyl acetate, acetone, tetrahydrofuran, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, ethyl formate, 2,2,2-trifluoroethanol, 2,2,3,3-hexafluoro-1-propanol, 1,3-difluoro-2-propanol, 1,1,1,3,3,3-hexafluoro- Examples include 2-methyl-2-propanol, 1,1,1,3,3,3-hexafluoro-2-propanol, 2,2,3,3,3-pentafluoro-1-propanol, and nitroethane. Methylene chloride, methyl acetate, ethyl acetate and acetone can be preferably used. Particularly preferred is methyl acetate.

  In addition to the organic solvent, the dope preferably contains 1 to 40% by mass of a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. When the proportion of alcohol in the dope increases, the web gels, and peeling from the metal support becomes easy. When the proportion of alcohol is small, a lactone ring-containing acrylic polymer in a non-chlorine organic solvent system ( A) It also has a role of promoting dissolution of the cellulose ester resin (B).

  In particular, at least a lactone ring-containing acrylic polymer (A) and a cellulose ester resin (B) are added to a solvent containing methylene chloride and a linear or branched aliphatic alcohol having 1 to 4 carbon atoms. A dope composition in which 15 to 45% by mass is dissolved is preferable.

  Examples of the linear or branched aliphatic alcohol having 1 to 4 carbon atoms include methanol, ethanol, n-propanol, iso-propanol, n-butanol, sec-butanol, and tert-butanol. Ethanol is preferred because of the stability of these dopes, the relatively low boiling point, and good drying properties.

  Hereinafter, the preferable film forming method of the optical film of the present invention will be described.

1) Dissolution process In an organic solvent mainly composed of a good solvent for the lactone ring-containing acrylic polymer (A) and cellulose ester resin (B), the lactone ring-containing acrylic polymer (A) and cellulose ester in a dissolution vessel. The step of dissolving the resin (B) and the additive while stirring to form a dope, or mixing the additive solution into the lactone ring-containing acrylic polymer (A) and the cellulose ester resin (B) solution to form a dope It is a process of forming.

  The dissolution of the lactone ring-containing acrylic polymer (A) and the cellulose ester resin (B) is carried out at normal pressure, at a temperature lower than the boiling point of the main solvent, at a pressure higher than the boiling point of the main solvent, A method performed by a cooling dissolution method as described in Kaihei 9-95544, JP-A-9-95557, or JP-A-9-95538, a method performed at a high pressure as described in JP-A-11-21379, etc. Although various dissolution methods can be used, a method of pressurizing at a pressure higher than the boiling point of the main solvent is particularly preferable.

  The total amount of the lactone ring-containing acrylic polymer (A) and the cellulose ester resin (B) in the dope is preferably in the range of 15 to 45% by mass. An additive is added to the dope during or after dissolution to dissolve and disperse, then filtered through a filter medium, defoamed, and sent to the next step with a liquid feed pump.

  Filtration is preferably performed using a filter medium having a collected particle size of 0.5 to 5 μm and a drainage time of 10 to 25 sec / 100 ml. In this method, the aggregate remaining when the fine particles are dispersed or the aggregate generated when the main dope is added is obtained by using a filter medium having a collected particle diameter of 0.5 to 5 μm and a drainage time of 10 to 25 sec / 100 ml. Can be removed. In the main dope, since the concentration of fine particles is sufficiently thinner than that of the additive solution, aggregates do not adhere to each other during filtration and the filtration pressure does not increase rapidly.

2) Casting process An endless metal belt 31 such as a stainless steel belt or a rotating metal drum that feeds the dope to a pressure die 30 through a liquid feed pump (for example, a pressurized metering gear pump) and transfers it indefinitely. This is a step of casting a dope from a pressure die slit to a casting position on a metal support.

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

3) Solvent evaporation step In this step, the web (the dope is cast on the casting support and the formed dope film is called a web) is heated on the casting support to evaporate the solvent.

  In order to evaporate the solvent, there are a method of blowing air from the web side and / or a method of transferring heat from the back side of the support by a liquid, a method of transferring heat from the front and back by radiant heat, and the like. The drying efficiency is good and preferable. A method of combining them is also preferably used. The web on the support after casting is preferably dried on the support in an atmosphere of 40 to 100 ° C. In order to maintain the atmosphere at 40 to 100 ° C., it is preferable to apply hot air at this temperature to the upper surface of the web or to heat by means such as infrared rays.

  From the viewpoint of surface quality, moisture permeability, and peelability, it is preferable to peel the web from the support within 30 to 120 seconds.

4) Peeling process It is the process of peeling the web which the solvent evaporated on the metal support body in a peeling position. The peeled web is sent to the next process.

  The temperature at the peeling position on the metal support is preferably 10 to 40 ° C, more preferably 11 to 30 ° C.

  In addition, it is preferable that the residual solvent amount at the time of peeling of the web on the metal support at the time of peeling is peeled in the range of 50 to 120% by mass depending on the strength of drying conditions, the length of the metal support, and the like. When peeling off when the amount of residual solvent is larger, if the web is too soft, the flatness at the time of peeling may be impaired, and slippage and vertical stripes may occur due to peeling tension. The amount of residual solvent is determined.

  The residual solvent amount of the web is defined by the following formula.

Residual solvent amount (%) = (mass before web heat treatment−mass after web heat treatment) / (mass after web heat treatment) × 100
Note that the heat treatment for measuring the residual solvent amount represents performing heat treatment at 115 ° C. for 1 hour.

  The peeling tension at the time of peeling the metal support and the film is usually 196 to 245 N / m. However, when wrinkles easily occur at the time of peeling, it is preferable to peel with a tension of 190 N / m or less. It is preferable to peel at a minimum tension that can be peeled to 166.6 N / m, and then peel at a minimum tension to 137.2 N / m, and particularly preferably peel at a minimum tension to 100 N / m.

  In the present invention, the temperature at the peeling position on the metal support is preferably -50 to 40 ° C, more preferably 10 to 40 ° C, and most preferably 15 to 30 ° C.

5) Drying and stretching step After peeling, a drying device 35 that alternately conveys the web through a plurality of rolls arranged in the drying device and / or a tenter stretching device 34 that clips and conveys both ends of the web with a clip are used. And dry the web.

  Generally, the drying means blows hot air on both sides of the web, but there is also a means for heating by applying microwaves instead of the wind. Too rapid drying tends to impair the flatness of the finished film. Drying at a high temperature is preferably performed from about 8% by mass or less of the residual solvent. Throughout the drying is generally carried out at 40-250 ° C. It is particularly preferable to dry at 40 to 160 ° C.

  When using a tenter stretching apparatus, it is preferable to use an apparatus that can independently control the film gripping length (distance from the start of gripping to the end of gripping) left and right by the left and right gripping means of the tenter. In the tenter process, it is also preferable to intentionally create sections having different temperatures in order to improve planarity. It is also preferable to provide a neutral zone between different temperature zones so that the zones do not interfere with each other.

  In addition, extending | stretching operation may be divided | segmented and implemented in multiple steps, and it is also preferable to implement biaxial stretching in a casting direction and a width direction. When biaxial stretching is performed, simultaneous biaxial stretching may be performed or may be performed stepwise. In this case, stepwise means that, for example, stretching in different stretching directions can be sequentially performed, stretching in the same direction is divided into multiple stages, and stretching in different directions is added to any one of the stages. Is also possible. That is, for example, the following stretching steps are possible.

Stretch in the casting direction-Stretch in the width direction-Stretch in the casting direction-Stretch in the casting direction Stretch in the width direction-Stretch in the width direction-Stretch in the casting direction-Stretch in the casting direction Axial stretching includes stretching in one direction and contracting the other while relaxing the tension. The preferable draw ratio of simultaneous biaxial stretching can be taken in the range of x1.01 to x1.5 times in both the width direction and the longitudinal direction.

  When the tenter is used, the residual solvent amount of the web is preferably 20 to 100% by mass at the start of the tenter, and it is preferable to perform drying while applying the tenter until the residual solvent amount of the web becomes 10% by mass or less. More preferably, it is 5% by mass or less.

  30-150 degreeC is preferable, as for the drying temperature in the case of performing a tenter, 50-120 degreeC is more preferable, and 70-100 degreeC is the most preferable.

  In the tenter process, it is preferable that the temperature distribution in the width direction of the atmosphere is small from the viewpoint of improving the uniformity of the film. The temperature distribution in the width direction in the tenter process is preferably within ± 5 ° C, and within ± 2 ° C. Is more preferable, and within ± 1 ° C. is most preferable.

6) Winding step This is a step of winding the optical film by the winder 37 after the residual solvent amount in the web is 2% by mass or less, and the dimensional stability is achieved by setting the residual solvent amount to 0.4% by mass or less. A film having good properties can be obtained.

  As a winding method, a generally used method may be used. There are a constant torque method, a constant tension method, a taper tension method, a program tension control method with a constant internal stress, and the like.

  The optical film of the present invention is preferably a long film. Specifically, the optical film has a thickness of about 100 m to 5000 m and is usually provided in a roll shape. Moreover, it is preferable that the width | variety of a film is 1.3-4m, and it is more preferable that it is 1.4-2m.

  Although there is no restriction | limiting in particular in the film thickness of the optical film of this invention, When using for the polarizing plate protective film mentioned later, it is preferable that it is 20-200 micrometers, it is more preferable that it is 25-100 micrometers, and it is 30-80 micrometers. It is particularly preferred.

(Polarizer)
The polarizing plate used in the present invention can be produced by a general method. It is preferable that an adhesive layer is provided on the back side of the optical film of the present invention, and is bonded to at least one surface of a polarizer produced by immersion and stretching in an iodine solution. The film may be used on the other surface, or another polarizing plate protective film may be used. For example, commercially available cellulose ester films (for example, Konica Minoltack KC8UX, KC4UX, KC5UX, KC8UY, KC4UY, KC12UR, KC8UCR-3, KC8UCR-4, KC8UCR-5, KV8UY-HA, KV8UX-RHA, OP Etc.) are preferably used.

  A polarizer, which is a main component of a polarizing plate, is an element that transmits only light having a plane of polarization in a certain direction. A typical polarizing film known at present is a polyvinyl alcohol polarizing film, which is a polyvinyl alcohol. There are one in which iodine is dyed on a system film and one in which dichroic dye is dyed. For the polarizer, a polyvinyl alcohol aqueous solution is formed into a film and dyed by uniaxial stretching or dyed or uniaxially stretched and then preferably subjected to a durability treatment with a boron compound.

As the pressure-sensitive adhesive used in the pressure-sensitive adhesive layer, a pressure-sensitive adhesive having a storage elastic modulus at 25 ° C. in the range of 1.0 × 10 ⁴ Pa to 1.0 × 10 ⁹ Pa in at least a part of the pressure-sensitive adhesive layer is used. It is preferable to use a curable pressure-sensitive adhesive that forms a high molecular weight body or a crosslinked structure by various chemical reactions after the pressure-sensitive adhesive is applied and bonded. Specific examples include, for example, urethane adhesives, epoxy adhesives, aqueous polymer-isocyanate adhesives, curable adhesives such as thermosetting acrylic adhesives, moisture-curing urethane adhesives, polyether methacrylate types, Examples include anaerobic pressure-sensitive adhesives such as ester-based methacrylate type and oxidized polyether methacrylate, cyanoacrylate-based instantaneous pressure-sensitive adhesives, and acrylate-peroxide-based two-component instantaneous pressure-sensitive adhesives. The pressure-sensitive adhesive may be a one-component type or a type that is used by mixing two or more components before use. The pressure-sensitive adhesive may be a solvent system using an organic solvent as a medium, or an aqueous system such as an emulsion type, a colloidal dispersion type, or an aqueous solution type that is a medium containing water as a main component. It may be a solvent type. The density | concentration of the said adhesive liquid should just be suitably determined with the film thickness after adhesion, the coating method, the coating conditions, etc., and is 0.1-50 mass% normally.

"Polarizer"
When using the optical film of this invention as a polarizing plate protective film, the preparation methods of a polarizing plate are not specifically limited, It can manufacture by a general method. The back side of the optical film of the present invention is subjected to alkali saponification treatment, and the treated optical film is bonded to at least one surface of a polarizer produced by immersing and stretching in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. It is preferable. 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 cellulose ester film can be used as the polarizing plate protective film used on the other surface. For example, as a commercially available cellulose ester film, KC8UX2M, KC4UX, KC5UX, KC4UY, KC8UY, KC12UR, KC8UCR-3, KC8UCR-4, KC4FR-1, KC8UY-HA, KC8UX-RHA (manufactured by Konica Minolta Opto, Inc.) Etc.) are preferably used. 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 films, such as cyclic olefin resin other than a cellulose-ester 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.

  In the polarizing plate of the present invention, a polarizing plate protective film of a cellulose derivative is preferably used on the surface opposite to the polarizing plate protective film using the optical film of the present invention as viewed from the polarizer, and a general-purpose TAC film Etc. can be used. 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, it may be affixed to a film containing a known functional layer as a constituent for display in order to prevent reflection, anti-glare, scratch resistance, dust adhesion prevention, brightness improvement, or the polarizing plate surface of the present invention. It is not limited to.

  In general, a retardation film is required to obtain a stable optical characteristic such that the above-described retardation Ro or Rt has little fluctuation. In particular, in a liquid crystal display device in a birefringence mode, these fluctuations may cause image unevenness.

  Since the long polarizing plate protective film contains a cellulose ester, the alkali treatment step can be utilized by utilizing saponification inherent to the cellulose ester. When the resin which comprises a polarizer is polyvinyl alcohol, this can be bonded with a polarizing plate protective film using the completely saponified polyvinyl alcohol aqueous solution similarly to the conventional polarizing plate protective film. For this reason, this invention is excellent in the point which can apply the conventional polarizing plate processing method, and is excellent especially in the point from which the roll polarizing plate which is elongate is obtained.

  When manufacturing a 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 applied before and / or after stretching of the film. Good. At this time, various surface treatments such as corona discharge treatment, plasma treatment, and chemical treatment can be performed as necessary.

  The optical film of the present invention has a dimensional stability of ± 2.0% in terms of dimensional variation at 80 ° C. and 90% RH, based on the dimensions of the film left at 23 ° C. and 55% RH for 24 hours. Is less than 1.0%, preferably less than 1.0%, more preferably less than 0.5%.

  When the optical film of the present invention is used for a polarizing plate as a retardation film, the retardation film itself has a variation within the above range, and the retardation retardation value and the orientation angle do not deviate from the original settings. Therefore, it is preferable in terms of display quality.

  A polarizer, which is a main component of a polarizing plate, is an element that allows only light of a plane of polarization in a certain direction to pass. A typical polarizer currently known is a polyvinyl alcohol-based polarizing film, which is polyvinyl alcohol. There are one in which iodine is dyed on a system film and one in which dichroic dye is dyed. For the polarizer, a polyvinyl alcohol aqueous solution is formed into a film and dyed by uniaxial stretching or dyed or uniaxially stretched and then preferably subjected to a durability treatment with a boron compound. The film thickness of the polarizer is 5 to 40 μm, preferably 5 to 30 μm, and particularly preferably 5 to 20 μm. On the surface of the polarizer, one surface of the optical 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 polarizer 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 orthogonal to the stretching (usually the width direction) ) Will grow. As the thickness of the polarizing plate protective film decreases, the expansion / contraction ratio of the polarizing plate increases, and in particular, the amount of contraction in the stretching direction of the polarizer increases. Normally, the direction of stretching of the polarizer is bonded to the casting direction (MD direction) of the polarizing plate protective film. Therefore, when thinning the polarizing plate protective film, it is particularly important to suppress the stretch rate in the casting direction. It is. Since the optical film of the present invention is extremely excellent in dimensional stability, it is suitably used as such a polarizing plate protective film.

  That is, even when the durability test is performed at 60 ° C. and 90% RH, the wavy unevenness does not increase, and even if the polarizing plate has an optical compensation film on the back side, the viewing angle characteristics fluctuate after the durability test. Good visibility can be provided without doing so.

  The polarizing plate is composed of a polarizer and a protective film that protects both sides of the polarizer, and can further be constructed by laminating a protective film on one surface of the polarizing plate and a separate film on the opposite surface. The protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection. In this case, the protect film is bonded for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal plate. Moreover, a separate film is used in order to cover the contact bonding layer bonded to a liquid crystal board, and is used for the surface side which bonds a polarizing plate to a liquid crystal cell.

<Liquid crystal display device>
A polarizing plate equipped with a polarizing plate protective film (including a case where it also serves as a retardation film) using the optical film of the present invention can exhibit high display quality as compared with a normal polarizing plate, particularly a multi-domain. Type liquid crystal display device, more preferably a multi-domain type liquid crystal display device using birefringence mode (for example, also referred to as MVA type liquid crystal display device), or a lateral electric field switching mode type liquid crystal display device (also referred to as IPS mode type liquid crystal display device). Suitable for use on).

  By using the polarizing plate of the present invention for a liquid crystal display device, various liquid crystal display devices having excellent visibility can be produced. The polarizing plate using the optical film of the present invention can be used for liquid crystal display devices of various drive systems such as STN, TN, OCB, HAN, VA (MVA, PVA), IPS, OCB. A VA (MVA, PVA) liquid crystal display device and an IPS mode liquid crystal display device are preferable. In particular, even a large-screen liquid crystal display device with a screen size of 30 or more can provide a liquid crystal display device with excellent visibility such as uneven coloring and front contrast with little environmental fluctuation and reduced light leakage. .

  In a liquid crystal display device using a polarizing plate equipped with a retardation film, when the optical film of the present invention is a retardation film, one polarizing plate is disposed on the liquid crystal cell, or on both sides of the liquid crystal cell. Arrange two. At this time, it can contribute to the improvement of display quality by using the polarizing plate protective film side which comprises a polarizing plate so that the liquid crystal cell of a liquid crystal display device may be faced. The polarizing plate using the optical film of the present invention can optically compensate the liquid crystal cell, and can provide a liquid crystal display device with improved display quality and excellent viewing angle characteristics.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example <Synthesis of lactone ring-containing acrylic resin LA-1>
In a 30 L reaction kettle equipped with a stirrer, temperature sensor, cooling pipe, nitrogen introduction pipe, 8000 g of methyl methacrylate (MMA), 2000 g of methyl 2- (hydroxymethyl) acrylate (MHMA), 10000 g of 4-methyl- 2-Pentanone (methyl isobutyl ketone, MIBK), 5 g of n-dodecyl mercaptan were charged, and the temperature was raised to 105 ° C. while passing nitrogen through this. When refluxed, 5.0 g of tertiary butyl peroxyisopropyl was used as an initiator. While adding carbonate (manufactured by Akzo Kayaku Co., Ltd., trade name: Kaya-Carbon Bic-75), a solution comprising 10.0 g of tertiary butyl peroxyisopropyl carbonate and 230 g of MIBK was added dropwise over 2 hours under reflux ( Solution polymerization at about 105 to 120 ° C.) Aging was carried out over a period of 4 hours in La.

  To the obtained polymer solution, 30 g of stearyl phosphate / distearyl phosphate mixture (manufactured by Sakai Chemical Co., Ltd., trade name: Phoslex A-18) was added and cyclized under reflux (about 90 to 120 ° C.) for 5 hours. A condensation reaction was performed. Subsequently, the polymer solution obtained by the cyclization condensation reaction was subjected to a vent having a barrel temperature of 260 ° C., a rotation speed of 100 rpm, a degree of vacuum of 13.3 to 400 hPa (10 to 300 mmHg), a rear vent number of 1, and a forevent number of 4 It is introduced into a type screw twin screw extruder (φ = 29.75 mm, L / D = 30) at a processing rate of 2.0 kg / hour in terms of resin amount, and cyclization condensation reaction and devolatilization are carried out in the extruder. A transparent pellet (LA-1) was obtained by extrusion.

  When the obtained pellet (LA-1) was measured for dynamic TG, a mass loss of 0.17% by mass was detected. Moreover, the weight average molecular weight of the pellet was 133,000, the melt flow rate was 6.5 g / 10 min, and the glass transition temperature was 131 ° C.

  The physical property values were measured by the following methods.

(Dynamic TG)
The pellet (LA-1) is once dissolved or diluted in tetrahydrofuran, poured into excess hexane or methanol for reprecipitation, and the taken out precipitate is vacuum dried (1 mmHg (1.33 hPa), 80 ° C., 3 hours or more) ) To remove volatile components and the like, and the obtained white solid resin was analyzed by the following method (dynamic TG method).

Measuring device: ThermoPlus2TG-8120DynamicTG (manufactured by Rigaku Corporation)
Measurement conditions: Sample amount 5-10 mg
Temperature increase rate: 10 ° C / min
Atmosphere: Nitrogen flow 200ml / min
Method: Step-like isothermal control method (controlled at a mass reduction rate of 0.005% / second or less between 60 ° C and 500 ° C)
(Weight average molecular weight)
The weight average molecular weight of the polymer was determined by polystyrene conversion of GPC (GPC system manufactured by Tosoh Corporation). Tetrahydrofuran was used as the developing solution.

(Thermal analysis of resin)
Thermal analysis of the resin was performed using DSC (manufactured by Rigaku Corporation, apparatus name: DSC-8230) under the conditions of about 10 mg of sample, a temperature rising rate of 10 ° C./min, and a nitrogen flow of 50 ml / min. The glass transition temperature (Tg) was determined by the midpoint method according to ASTM-D-3418.

(Melt flow rate)
The melt flow rate was measured at a test temperature of 240 ° C. and a load of 10 kg based on JIS-K6874.

(optical properties)
The refractive index anisotropy of the optical film, in-plane retardation Ro550 at a wavelength of 550 nm, and out-of-plane retardation Rt550 at a wavelength of 550 nm were measured using KOBRA-21ADH manufactured by Oji Scientific Instruments. Visible light transmittance was measured using NDH-1001DP manufactured by Nippon Denshoku Industries Co., Ltd.

<Synthesis of lactone ring-containing acrylic resin LA-2>
In a 30 L reaction kettle equipped with a stirrer, temperature sensor, cooling pipe, and nitrogen introduction pipe, 6000 g of methyl methacrylate (MMA), 2000 g of methyl 2- (hydroxymethyl) acrylate (MHMA), 2000 g of benzyl methacrylate (BzMA), 10000 g of toluene was charged. Next, while flowing nitrogen through the reaction kettle, the temperature in the reaction kettle is raised to 105 ° C., and after the reflux is started, t-amyl peroxyisononanoate (trade names: Lupasol 570, Atofina Yoshitomi ( At the same time as adding 10.0 g), an initiator solution consisting of 20.0 g of t-amylperoxyisononanoate and 100 g of toluene was added dropwise over 2 hours while refluxing (about 105 to 110 ° C.). Solution polymerization was performed. After the dropwise addition of the t-amyl peroxyisononanoate / toluene solution, aging was performed for an additional 4 hours.

  The reaction rate of the obtained polymer was 95.7%, the content of the MHMA structural unit in the polymer was 19.8% by mass, and the content of the BzMA structural unit was 20.2%.

  To the obtained polymer solution, 10 g of an octyl phosphate / dioctyl phosphate mixture (trade name: Phoslex A-8, manufactured by Sakai Chemical Co., Ltd.) was added and cyclized and condensed under reflux (about 80 to 105 ° C.) for 2 hours. The reaction was further carried out, and a cyclization condensation reaction was carried out at 240 ° C. for 1.5 hours under pressure (up to a gauge pressure of about 1.6 MPa) in an autoclave using a heating medium at 240 ° C.

  The polymer solution obtained by the above cyclization condensation reaction is a bent type screw having a barrel temperature of 250 ° C., a rotation speed of 100 rpm, a degree of vacuum of 13.3 to 400 hPa (10 to 300 mmHg), a rear vent number of 1, and a forevent number of 4. It is introduced into a twin-screw extruder (φ = 29.75 mm, L / D = 30) at a processing rate of 2.0 kg / hour in terms of resin amount, and a cyclization condensation reaction and devolatilization are carried out in the extruder, By taking out, a transparent pellet (LA-2) was obtained.

When the dynamic pellet was measured about the obtained pellet (LA-2), the mass reduction | decrease of 0.20 mass% was detected. The pellet (LA-2) had a weight average molecular weight of 115,000, a melt flow rate (MFR) of 49.5 g / 10 minutes, and a glass transition temperature (Tg) of 124 ° C. ^{Incidentally,} 1 H-NMR-containing determined from measurements, BzMA structural units in the pellets (LA-2) (product name: FT-NMR UNITY plus400,400MHz, Varian Inc., solvent: mesitylene: chloroform, internal standard) The amount was 21.7% by mass.

<Synthesis of lactone ring-containing acrylic resin LA-3>
The amount of the initiator (t-amyl peroxy isononanoate) was changed to 60% of the synthesis example of LA-2 (that is, the amount of t-amyl peroxy isononanoate charged after the start of reflux was 6.0 g, The amount of amyl peroxy isononanoate in the t-amyl peroxy isononanoate / toluene solution to be dropped is 12.0 g), and the amounts of MMA, MHMA and BzMA used are changed to the values shown in Table 2. The same operation as in Production Example LA-2 was performed to obtain a transparent pellet (LA-3).

<Synthesis of lactone ring-containing acrylic resin LA-4>
A transparent pellet (LA-4) was obtained in the same manner as in the synthesis example of LA-2 except that the amounts of MMA, MHMA, and BzMA were changed to the values shown in Table 1.

[Production of optical film]
<Preparation of optical film 1>
(Dope solution composition 1)
Pellet LA-1 64 parts by weight Cellulose ester (cellulose acetate propionate, total acyl group substitution degree 2.75, acetyl group substitution degree 0.19, propionyl group substitution degree 2.56, Mw = 200000)
34 parts by mass Additive Example Compound A-2 2 parts by mass Methylene chloride 300 parts by mass Ethanol 40 parts by mass The above composition was sufficiently dissolved while heating to prepare a dope solution.

(Formation of optical film 1)
The prepared dope solution was uniformly cast on a stainless steel band support at 22 ° C. and 2 m width using a belt casting apparatus. With the stainless steel band support, the solvent was evaporated until the amount of residual solvent reached 100%, and peeling was performed from the stainless steel band support with a peeling tension of 162 N / m.

  The solvent of the peeled resin web was evaporated at 35 ° C., slit to 1.6 m width, and then dried at 135 ° C. while being stretched 1.1 times in the width direction by a tenter. At this time, the residual solvent amount when starting stretching with a tenter was 10%.

  After stretching with a tenter, relaxation was performed at 130 ° C. for 5 minutes, and then drying was completed while transporting a drying zone at 120 ° C. and 140 ° C. with many rolls, slitting to a width of 1.5 m, and a width of 10 mm at both ends of the film A knurling process having a height of 5 μm was performed, and the film was wound around a core having an initial tension of 220 N / m and a final tension of 110 N / m, and an inner diameter of 15.24 cm.

  The draw ratio in the MD direction calculated from the rotational speed of the stainless steel band support and the operating speed of the tenter was 1.1 times.

  The residual solvent amount of the optical film 1 described in Table 1 was 0.1%, the film thickness was 60 μm, and the winding length was 4000 m.

<Preparation of optical films 2-14>
In the production of the optical film 1, the same applies except that the type of lactone ring-containing acrylic resin, the amount ratio of the lactone ring-containing acrylic resin and the cellulose ester, and the type and amount of additives are changed as shown in Table 2. Optical films 2 to 14 were produced.

[Evaluation of optical film]
(Phase difference measurement)
Using an automatic birefringence meter KOBRA-21ADH (manufactured by Oji Scientific Instruments Co., Ltd.), the film was allowed to stand for 24 hours in an environment of 23 ° C. and 55% RH. .

  Retardation was calculated using the following formulas (i) and (ii).

Formula (i): Ro = (nx−ny) × d
Formula (ii): Rt = ((nx + ny) / 2−nz) × d
(Where nx is the refractive index in the slow axis direction in the film plane, ny is the refractive index in the direction perpendicular to the slow axis in the plane, nz is the refractive index in the film thickness direction, and d is the film thickness (nm )
(Light leakage)
The obtained optical film is sandwiched between two polarizers arranged in a crossed Nicol state with a polarizing plate, that is, in an orthogonal state (crossed Nicol state), irradiated with light from the outside of one polarizing plate, It observed visually from the outside and evaluated on the following reference | standard.

○: There is no light transmission, and the entire dark field is uniform. △: Weakly streaky light / darkness is observed partially. ×: Strong streaky light / darkness is observed partially (breaking when slitting).
At the time of forming the optical film, the frequency of film breakage during conveyance was evaluated according to the following criteria.

○: No break and no break at the slit before the tenter Δ: No break occurs at the slit before the tenter, but often breaks ×: Many breaks occur at the slit before the tenter Table 2 shows the results of evaluation.

  From Table 2, the optical films 1 to 8 of the present invention containing the acrylic polymer having a lactone ring structure, the cellulose ester resin, and the compound represented by the general formula (1) are the optical films 9 to 14 of the comparative examples. On the other hand, it can be seen that light leakage is improved, there is no breakage during film formation, and a phase difference is developed.

(Production and evaluation of polarizing plate)
A 120 μm-thick polyvinyl alcohol film was immersed in an aqueous solution containing 1 part by mass of iodine, 2 parts by mass of potassium iodide, and 4 parts by mass of boric acid, and stretched 4 times at 50 ° C. to produce a polarizer.

  The optical films 1 to 8 of the present invention produced in Example 1 and the comparative optical films 9 to 14 are double-wrapped with a polyethylene sheet, and are stored at 25 ° C. and 50% RH by the storage method as shown in FIG. This was stored for 30 days under conditions of 40 ° C. and 80% RH. Thereafter, the polyethylene sheet was removed, and the film unwound from each original fabric sample was alkali-treated with a 2.5 mol / L sodium hydroxide aqueous solution at 40 ° C. for 60 seconds, and further washed with water and dried to alkali-treat the surface.

  The protective film is obtained by bonding the alkali-treated surfaces of the optical films 1 to 8 of the present invention and the comparative optical films 9 to 14 to both surfaces of the polarizer using a completely saponified polyvinyl alcohol 5% aqueous solution as an adhesive. The formed polarizing plates 1 to 8 of the present invention and comparative polarizing plates 9 to 14 were produced.

[Evaluation of polarizing plate]
Next, the durability of the polarizing plate was evaluated as follows.

(durability)
Two 500 mm × 500 mm polarizing plate samples were cut out from the single polarizing plate produced above, heat-treated (condition: left at 90 ° C. for 100 hours), and the vertical or horizontal center line portion when it was in an orthogonal state. The length of the white part of the larger edge was measured, and the ratio to the side length (500 mm) was calculated, and the following determination was made according to the ratio. Edge blanking can be determined visually by the fact that the edge portion of the polarizing plate that does not transmit light in an orthogonal state passes light. In the state of the polarizing plate, the display of the edge portion becomes invisible.

A: Edge blank is less than 5% (a level at which there is no problem as a polarizing plate)
○: White edge of the edge is 5% or more and less than 10% (a level that does not cause a problem as a polarizing plate)
Δ: White edge of edge is 10% or more and less than 20% (a level that can be managed as a polarizing plate)
X: White outline of edge is 20% or more (a problematic level as a polarizing plate)
The results obtained as described above are shown in Table 3.

  From Table 3, it turns out that the polarizing plates 1-8 of this invention are excellent in durability with respect to 9-14 of a comparative polarizing plate.

(Characteristic evaluation as a liquid crystal display device)
The polarizing plate of the 15-inch liquid crystal display VL-1530S manufactured by Fujitsu, which is a VA-type liquid crystal display device, was peeled off, and the polarizing plate produced above was cut according to the size of the liquid crystal cell. The two polarizing plates prepared as described above were bonded so that the polarizing axes of the polarizing plates were not perpendicular to each other so as to sandwich the liquid crystal cell, to produce a 15-inch VA color liquid crystal display, and the polarization of the cellulose ester film When the characteristics as a plate were evaluated, the liquid crystal display device using the polarizing plates 1 to 8 of the present invention had a high contrast and excellent display properties compared to the liquid crystal display device using the comparative polarizing plates 9 to 14. Indicated. Thereby, it was confirmed that the polarizing plates 1-8 of this invention are excellent as a polarizing plate for image display apparatuses, such as a liquid crystal display.

  This liquid crystal display device was installed on a backlight, and an image was observed from a direction of 70 degrees tilted from the normal direction in an azimuth direction of 45 degrees with respect to the optical axis of the orthogonal polarizing plate.

  As a result, a clear image was observed, and the polarizing plate of the present invention had good viewing angle characteristics.

110 Core body 117 Support plate 118 Base 120 Optical film original

Claims (5)

An optical film containing an acrylic polymer having a lactone ring structure and a cellulose ester resin, wherein the optical film contains a compound represented by the following general formula (1).

(Wherein R ^{1 to} R ⁷ , R ⁹ and R ¹⁰ each independently represent a hydrogen atom or a substituent, at least one of R ^{1 to} R ⁵ represents an electron donating group, and R ⁸ represents a hydrogen atom. , An alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, an alkynyl group having 2 to 6 carbon atoms, an aryl group having 6 to 12 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, and 6 to 6 carbon atoms 12 represents an aryloxy group, an alkoxycarbonyl group having 2 to 12 carbon atoms, an acylamino group having 2 to 12 carbon atoms, an acyloxy group, a cyano group, or a halogen atom.)   The optical film according to claim 1, wherein the electron donating group of the compound represented by the general formula (1) is an alkoxy group. The optical film according to claim 1 or 2, wherein the compound represented by the general formula (1) is a compound represented by the following general formula (2).

(In the formula, R ² , R ⁴ and R ⁵ each independently represent a hydrogen atom or a substituent, R ²¹ and R ²² each independently represent an alkyl group having 1 to 4 carbon atoms, and X ¹ represents 2 carbon atoms. Represents a -7 alkynyl group, an aryl group having 6-12 carbon atoms, an alkoxycarbonyl group having 2-12 carbon atoms, an acylamino group having 2-7 carbon atoms, or a cyano group.)   A polarizing plate comprising the optical film according to claim 1 on at least one surface of a polarizer.   A liquid crystal display device comprising the polarizing plate according to claim 4 on at least one surface of a liquid crystal cell.

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