TW201821473A - Modifying agent for cellulose ester resin, cellulose ester resin composition, and optical film - Google Patents

Abstract

The purpose of the present invention is to provide a modifying agent that imparts excellent moisture impermeability to a cellulose ester resin and does not inhibit the inherent transparency of the cellulose ester resin. The present invention relates to a modifying agent for cellulose ester resin, said agent including an ester compound represented by formula (1): [in formula (1), A1 and A2 are the same or different and represent an aliphatic dicarboxylic acid residue. G1 represents a dihydric alcohol residue, wherein the dihydric alcohol residue is an aliphatic dihydric alcohol residue or a combination of an aliphatic dihydric alcohol residue and an aromatic dihydric alcohol residue. M1 and M2 are the same or different and represent an aromatic monoalcohol residue. n is an integer of 1 or higher].

Description

Modifier for cellulose ester resin, cellulose ester resin composition and optical film

The present invention relates to a cellulose ester resin modifier, a cellulose ester resin composition, and an optical film.

BACKGROUND ART Conventionally, cellulose ester resins have been used as support for photographs because of their strong toughness and transparency. Cellulose ester resins are not only highly optically transparent, but also highly isotropic, so in recent years they have been used as optical materials for devices that use polarized light, such as liquid crystal displays, as protective films for polarizers, Supports such as optical compensation films that optimize the display when viewed from an oblique direction.

When a film made of the aforementioned cellulose ester resin is used as a protective film for a polarizer used in a polarizing plate of a member for a liquid crystal display, the cellulose ester film cannot sufficiently prevent the invasion of moisture such as moisture, so that the polarizer is deteriorated, Problems such as peeling between the polarizer and the protective film. Therefore, conventionally, a plasticizer such as triphenyl phosphate was added to the cellulose ester resin, and a film having moisture permeability resistance was used as a polarizer protective film.

In recent years, the demand for thinner liquid crystal displays is increasing. With the thinning of liquid crystal displays, the thinning of protective films for polarizers has been reviewed. When the film thickness of the polarizer protective film containing the aforementioned plasticizer and cellulose ester resin is reduced to a required level, there is a problem that the moisture permeability is significantly reduced. In order to obtain sufficient moisture permeability resistance, it is considered to increase the amount of the plasticizer, but at this time, there is a possibility that problems such as bleeding of the plasticizer and reduction in strength of the film itself may occur. Although it has also been proposed that a polymer (polyester or polyether ester) having a weight-average molecular weight in a specific range is added to a cellulose ester resin to improve the moisture permeability resistance of a film (Patent Document 1), it is not possible to obtain sufficient Effect.

Then, various types of polyester compounds have been examined as modifiers for cellulose ester resins (for example, Patent Documents 2 to 6). Patent Document 2 describes a polyester terminated with an aromatic monocarboxylic acid in a condensate of an aromatic dicarboxylic acid and a low-carbon diol. Patent Document 3 describes a polyester terminated with an aliphatic monohydric alcohol or an aliphatic monocarboxylic acid in a condensate of an aliphatic dicarboxylic acid and a low-carbon diol. Patent Document 4 describes a polyester terminated with an ether alcohol in a condensate of a polybasic acid and a polyhydric alcohol containing a specific amount of an aromatic dicarboxylic acid. Patent Document 5 describes a polyester of a condensate of an aromatic dicarboxylic acid and a diol. Patent Document 6 describes a polyester terminated with acetic acid or benzoic acid in a condensate of an aliphatic dicarboxylic acid, an aromatic dicarboxylic acid, and a low-carbon diol. However, the film formed using the modifiers and cellulose ester resins described in Patent Documents 2 to 6 cannot be said to have sufficient moisture permeability, and it is a level that requires other additives (moisture-proofing agents). Therefore, a polyester-based modifier capable of imparting excellent moisture permeability resistance to a cellulose ester resin is desired.

Prior Technical Documents Patent Documents Patent Document 1: Japanese Patent Laid-Open No. 2002-022956 Patent Document 2: Japanese Patent Laid-Open No. 2006-282987 Patent Document 3: Japanese Patent Laid-Open No. 2009-046531 Patent Document 4: Japanese Patent Laid-Open No. 2009- Patent Document No. 173742 Patent Document 5: Japanese Patent Application Laid-Open No. 2010-138379 Patent Document 6: International Publication No. 10/087219

Summary of the Invention Problems to be Solved by the Invention The main object of the present invention is to provide a modifier which imparts excellent moisture permeability resistance to a cellulose ester resin and does not hinder the transparency inherent in the cellulose ester resin. Still another object of the present invention is to provide a cellulose ester resin composition containing the modifier and a cellulose ester resin film for optical use, which is excellent in moisture permeability and transparency and is made from the resin composition.

Means for Solving the Problem The present inventors devoted their efforts to developing a modifier that imparts excellent moisture permeability resistance to a cellulose ester resin and does not hinder the transparency inherent in the cellulose ester resin. As a result, it has been found that The above-mentioned problem can be solved by using a specific ester compound terminated with an aromatic monohydric alcohol as a modifier for a cellulose ester resin. The present invention has been completed based on the above findings.

That is, the present invention relates to a modifier for a cellulose ester resin, a cellulose ester resin composition, and a film for optics as shown in the following items 1 to 10.

Item 1. A modifier for a cellulose ester resin, comprising an ester compound represented by the following formula (1): [Chemical Formula 1]

[In formula (1), A ¹ and A ² represent the same or different aliphatic dicarboxylic acid residues. G ¹ represents a diol residue, and the aforementioned diol residue is an aliphatic diol residue, or a combination of an aliphatic diol residue and an aromatic diol residue. M ¹ and M ² represent the same or different aromatic monohydric alcohol residues. n is an integer of 1 or more]. Item 2. The modifier for a cellulose ester resin according to Item 1, wherein the number average molecular weight of the ester compound is 500 to 2500. Item 3. The modifier for a cellulose ester resin according to Item 1 or 2, wherein M ¹ and M ² are selected from the group consisting of phenol, 2-cresol, 3-cresol, 4-cresol, and benzyl alcohol. , 2-methylbenzyl alcohol, 3-methylbenzyl alcohol, 4-methylbenzyl alcohol, 1-phenylethanol, 2-phenylethanol, 2-benzyloxyethanol, and 2-phenoxyethanol Residues of the group monohydric alcohols. Item 4. The modifier for a cellulose ester resin according to item 3, wherein the M ¹ and M ² are at least one aromatic selected from the group consisting of 2-benzyloxyethanol and 2-phenoxyethanol Residues of the group monohydric alcohols. Item 5. The modifier for a cellulose ester resin according to any one of Items 1 to 4, wherein G ¹ is the aliphatic diol residue. Item 6. The modifier for a cellulose ester resin according to any one of Items 1 to 4, wherein G ¹ is a combination of the aliphatic diol residue and the aromatic diol residue, and the ester compound The molar ratio of the aromatic diol residue in the diol residue in the above is 80% or less. Item 7. The modifier for a cellulose ester resin according to any one of Items 1 to 6, wherein the ester compound has a hydroxyl value of 30 mgKOH / g or less. Item 8. The modifier for a cellulose ester resin according to any one of Items 1 to 7, wherein the acid value of the ester compound is 3 mgKOH / g or less. Item 9. A cellulose ester resin composition comprising the modifier for a cellulose ester resin according to any one of items 1 to 8, and a cellulose ester resin. Item 10. An optical film comprising the cellulose ester resin composition according to Item 9.

Advantageous Effects of Invention According to the present invention, it is possible to provide a modifier which imparts excellent moisture permeability resistance to a cellulose ester resin and does not hinder the transparency inherent in the cellulose ester resin. By adding the modifier for a cellulose ester resin of the present invention to a cellulose ester resin, it is possible to impart excellent transparency and excellent transparency to a film made of a cellulose ester resin composition containing the modifier and a cellulose ester resin. Moisture resistance.

Modes for Carrying Out the Invention The modifier for cellulose ester resin, cellulose ester resin composition, and optical film of the present invention will be described.

1. Modifier for cellulose ester resin The modifier for cellulose ester resin of the present invention includes an ester compound represented by the following formula (1):

[Chemical Formula 2]

[In formula (1), A ¹ and A ² represent the same or different aliphatic dicarboxylic acid residues. G ¹ represents a diol residue, and the aforementioned diol residue is an aliphatic diol residue, or a combination of an aliphatic diol residue and an aromatic diol residue. M ¹ and M ² represent the same or different aromatic monohydric alcohol residues. n is an integer of 1 or more].

<Ester compound> The ester compound is a reaction product of an aliphatic dicarboxylic acid, a diol, and an aromatic monohydric alcohol. That is, the above-mentioned ester compound has a two-terminal carboxylic acid of a polyester (a polymer having a repeating unit based on an aliphatic dicarboxylic acid and a glycol) obtained by esterifying an aliphatic dicarboxylic acid with a diol. Aromatic monohydric alcohol-terminated structure.

By including the aforementioned ester compound in the modifier for a cellulose ester resin of the present invention, the transparency and transmission resistance of an optical film obtained from a cellulose ester resin composition containing the modifier and the cellulose ester resin can be significantly improved. Wet.

Here, the term "aliphatic dicarboxylic acid residue" refers to a group remaining after removing hydroxyl groups from two carboxyl groups of the aliphatic dicarboxylic acid. The so-called diol residue refers to the residue remaining after removing hydrogen from the two hydroxyl groups of the diol. The so-called aromatic monohydric alcohol residue refers to a group remaining after removing hydrogen from a hydroxyl group possessed by the aromatic monohydric alcohol.

The aliphatic dicarboxylic acid that forms the aliphatic dicarboxylic acid residues represented by A ¹ and A ² in the above formula (1) by reaction may be linear, branched, or alicyclic structure. The number of carbon atoms in the aliphatic dicarboxylic acid is preferably 2 to 15, preferably 2 to 10, and most preferably 2 to 4.

Specific examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and 3-ethyl-3-formaldehyde. Glutaric acid, azelaic acid, heptane-4,4-dicarboxylic acid, sebacic acid, undecanedicarboxylic acid, dodecanedicarboxylic acid, 1,1-cyclopropanedicarboxylic acid, 1, 1-cyclobutanedicarboxylic acid, 1,2-cyclohexanedicarboxylic acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, 1,1-cyclopentanedicarboxylic acid Acetic acid, maleic acid, fumaric acid and acetylene dicarboxylic acid.

Among these aliphatic dicarboxylic acids, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and 1,2-cyclohexanedicarboxylic acid are preferred. , 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, maleic acid and fumaric acid, particularly preferred are oxalic acid, malonic acid and succinic acid.

The aliphatic dicarboxylic acid includes carboxylic acid derivatives such as esterified products, acid chlorides, and acid anhydrides. These aliphatic dicarboxylic acids may be used alone or in combination of two or more.

The glycol residue represented by G ¹ in the above formula (1) includes an aliphatic glycol residue. Since the modifier contains an aliphatic diol residue, the compatibility with the cellulose ester resin is improved, so the transparency of the obtained film can be maintained. As the diol that forms the diol residue represented by G ¹ in the formula (1) by reaction, only an aliphatic diol may be used, or an aliphatic diol and an aromatic diol may be combined. After use. Particularly preferred is the use of only aliphatic diols.

The aliphatic diol may be linear or branched, or may have an alicyclic structure. The number of carbon atoms in the aliphatic diol is preferably from 2 to 15, preferably from 2 to 6, and even more preferably from 2 to 4.

Examples of the aliphatic diol include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, and 2 2,2-dimethyl-1,3-propanediol, 2,2-diethyl-1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol , 2,3-butanediol, 1,5-pentanediol, 1,5-hexanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 2-ethyl -1,3-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,2-cyclopentanediol, 1,3-cyclopentanediol, 1,2-cyclopentanediol Hexanediol, 1,4-cyclohexanediol, 1,4-cyclohexanedimethanol and 1,1-cyclohexanediethanol.

Among these aliphatic diols, ethylene glycol, 1,2-propylene glycol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,2-butanediol, 1, 3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-cyclohexanediol, and 1,4-cyclohexanediol, particularly preferably ethylene glycol, 1,2 -Propylene glycol and 2-methyl-1,3-propanediol.

These aliphatic diols may be used alone or in combination of two or more kinds.

The aromatic diol refers to a compound having at least two aromatic ring structures in a molecule and having two hydroxyl groups. The hydroxyl group in the compound may be directly bonded to an aromatic ring or other functional groups such as an alkyl group bonded to the aromatic ring. The number of carbon atoms in the aromatic diol is preferably 6 to 25, preferably 6 to 15, and particularly preferably 6 to 10.

Examples of the aromatic diol include hydrogen roller, resorcinol, 2,2'-biphenyldiol, 4,4'-biphenyldiol, 2,2-bis (4-hydroxybenzene) Propyl) propane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 2,2-bis (4-hydroxyphenyl) butane, bis (4-hydroxyphenyl) diphenyl Methane, 2,2-bis (3-methyl-4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) ethane, bis (4-hydroxyphenyl) methane, 2,2- Bis (4-hydroxy-3-isopropylphenyl) propane, 1,3-bis (2- (4-hydroxyphenyl) -2-propyl) benzene, 1,4-bis (2- (4- Hydroxyphenyl) -2-propyl) benzene, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,2-benzenedimethanol, 1,4-benzenedimethanol, 1,2-benzenediphenyl Ethanol, 1,4-benzenediethanol and 2,2 '-(1,3-phenylene) bis (2-propanol).

Among these aromatic diols, hydrogen roll, resorcinol, 2,2'-biphenyldiol, 4,4'-biphenol, and bis (4-hydroxyphenyl) methane are preferred. , 1,2-benzenedimethanol, 1,4-benzenedimethanol, 1,2-benzenediethanol and 1,4-benzenediethanol, particularly preferably hydrogen roller, resorcinol, 1,2-benzenediethanol Methanol, 1,4-benzenedimethanol, 1,2-benzenediethanol and 1,4-benzenediethanol.

These aromatic diols may be used alone or in combination of two or more kinds.

When the diol residue represented by G ¹ is a combination of an aliphatic diol residue and an aromatic diol residue, the aforementioned aromatic diol residue in the aforementioned diol residue in the aforementioned ester compound The molar ratio is preferably 80% or less, preferably 70% or less, and particularly preferably 60% or less.

Here, the Mohr ratio of the aromatic diol residue being "80% or less" means that the Mohr ratio is "more than 0% and 80% or less". The lower limit of the Mohr ratio is preferably 0.01%, more preferably 0.1%, more preferably 1%, and even more preferably 10%.

The aromatic monohydric alcohol that forms the aromatic monohydric alcohol residues represented by M ¹ and M ² in the formula (1) by reaction refers to a compound having at least one aromatic ring structure in the molecule and having one hydroxyl group. Since the modifier contains an aromatic monohydric alcohol residue, the moisture permeability of the obtained film can be improved. This aromatic monohydric alcohol functions as a capping agent for an ester compound. The hydroxyl group in the compound may be directly bonded to the aromatic ring, or may be bonded to other substituents such as an alkyl group bonded to the aromatic ring. A particularly preferred form of the aforementioned aromatic monohydric alcohol is a hydroxyl group bonded to an alkyl, alkoxy, or alkoxyalkyl group bonded to an aromatic ring, and a most preferred form is a hydroxyl group bonded to an alkoxy group bonded to an aromatic ring . The carbon number of the aforementioned aromatic monohydric alcohol is preferably from 6 to 20, preferably from 7 to 15, and particularly preferably from 8 to 10.

Examples of the aromatic monohydric alcohol include phenol, 2-cresol, 3-cresol, 4-cresol, 2-ethylphenol, 3-ethylphenol, 4-ethylphenol, and 2,3-xylenol. , 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, 3,5-xylenol, 2-propylphenol, 4-propylphenol , 2,3,5-tricresol, 2,3,6-tricresol, 2,4,6-tricresol, 1-naphthol, 2-naphthol, 2-phenylphenol and 4-phenylphenol, etc. An aromatic monohydric alcohol whose hydroxyl group is directly bonded to an aromatic ring; benzyl alcohol, 2-methylbenzyl alcohol, 3-methylbenzyl alcohol, 4-methylbenzyl alcohol, 2-ethylbenzyl alcohol, 3-ethylbenzyl alcohol, 4-ethylbenzyl alcohol Alcohol, 2,3-dimethylbenzyl alcohol, 2,4-dimethylbenzyl alcohol, 3,5-dimethylbenzyl alcohol, 2,6-dimethylbenzyl alcohol, 4-isopropylbenzyl alcohol, 2,4,6 -Trimethylbenzyl alcohol, 3,4,5-trimethylbenzyl alcohol, 3-phenoxybenzyl alcohol, 1-phenylethanol, 2-phenylethanol, 3-phenyl-1-propanol, 1-phenoxy-2- An aromatic monohydric alcohol in which hydroxyl groups such as propanol, 2-benzyloxyethanol, and 2-phenoxyethanol are bonded to other substituents bonded to an aromatic ring.

Among these aromatic monohydric alcohols, phenol, 2-cresol, 3-cresol, 4-cresol, 2-ethylphenol, 3-ethylphenol, 4-ethylphenol, 4-propylphenol, and benzyl are preferred. Alcohol, 2-methylbenzyl alcohol, 3-methylbenzyl alcohol, 4-methylbenzyl alcohol, 2-ethylbenzyl alcohol, 3-ethylbenzyl alcohol, 4-ethylbenzyl alcohol, 4-isopropylbenzyl alcohol, 1-phenylethanol, 2-phenylethanol, 3-phenyl-1-propanol, 2-phenylphenol, 4-phenylphenol, 2-benzyloxyethanol and 2-phenoxyethanol, more preferably phenol, 2-cresol, 3 -Cresol, 4-cresol, benzyl alcohol, 2-methylbenzyl alcohol, 3-methylbenzyl alcohol, 4-methylbenzyl alcohol, 1-phenylethanol, 2-phenylethanol, 2-benzyloxyethanol, and 2-phenoxy Ethanol, particularly preferably benzyl alcohol, 2-methylbenzyl alcohol, 3-methylbenzyl alcohol, 4-methylbenzyl alcohol, 1-phenylethanol, 2-phenylethanol, 2-benzyloxyethanol, and 2-phenoxyethanol, most preferably It is 2-benzyloxyethanol and 2-phenoxyethanol.

These aromatic monohydric alcohols may be used alone or in combination of two or more kinds.

n represents the number of repeating units. n is an integer of 1 or more, usually 1-20, preferably 2-15, and more preferably 3-10. If it is the said range, it will be excellent in compatibility with a cellulose ester resin, and the effect of providing plasticity will also be excellent.

The number average molecular weight of the aforementioned ester compound is preferably 500 to 2500, preferably 700 to 2000, and particularly preferably 800 to 1800. If the number average molecular weight of the aforementioned ester compound is within the above range, the modifier for cellulose ester resins is excellent in resistance to bleeding even under high temperature and humidity, and is not easily volatile even under high temperature conditions such as a film manufacturing step, and can be suppressed or improved. Pollution of devices and operating environment during manufacturing steps. In addition, the number average molecular weight is a value measured by a gel permeation chromatography (GPC) converted to polystyrene using tetrahydrofuran (THF) as an eluent. The detailed measurement conditions are described in the examples.

The acid value of the aforementioned ester compound is derived from the carboxyl group which is not present in the terminal of the polyester which can be generated when the glycol reacts with the aliphatic dicarboxylic acid, and which is not blocked by the aforementioned aromatic monohydric alcohol. In terms of imparting excellent moisture permeability resistance to the film and maintaining the stability of the cellulose ester resin modifier, the content of the polyester having a carboxyl group at the terminal contained in the aforementioned cellulose ester resin modifier should be as high as possible. Possibly few. Therefore, the optimum value of the acid value is 0, but even when the acid value is present, the effects of the present invention can be sufficiently exhibited as long as it is in the range shown below. The upper limit when having an acid value is preferably 3 mgKOH / g or less, preferably 1 mgKOH / g or less, and particularly preferably 0.7 mgKOH / g or less. The lower limit as the acid value is preferably about 0.005 mgKOH / g.

The hydroxyl value of the aforementioned ester compound is derived from the hydroxyl group existing at the terminal of the polyester that can be generated when the glycol is reacted with the aliphatic dicarboxylic acid; it is derived from the unreacted hydroxyl group of the glycol used. Because the affinity of the hydroxyl group and water is strong, in order to maintain the moisture permeability resistance of the obtained film, the hydroxyl group should be less. The optimum value of the hydroxyl value is 0, but even when the hydroxyl value is present, the effect of the present invention can be sufficiently exhibited as long as it is in the range shown below. The upper limit when having a hydroxyl value is preferably 30 mgKOH / g or less, preferably 25 mgKOH / g, or particularly preferably 15 mgKOH / g or less. As the lower limit when having a hydroxyl value, it should be about 0.1 mgKOH / g.

<The manufacturing method of an ester compound> The said ester compound can be obtained by making the said aliphatic dicarboxylic acid, the said diol, and the said aromatic monohydric alcohol react. Specifically, the aliphatic dicarboxylic acid, the diol, and the aromatic monohydric alcohol may be subjected to an esterification reaction in the presence of an esterification catalyst, if necessary, for example, in a temperature range of 100 to 250 ° C. by a conventional method. About 10 to 25 hours, the aforementioned ester compound is produced. The conditions such as the temperature and time of the esterification reaction are not particularly limited, and can be appropriately set.

The aforementioned aliphatic dicarboxylic acid, the aforementioned diol, and the aforementioned aromatic monohydric alcohol may be used respectively. The ratio of each of the above components used in manufacturing can be changed according to the type of the component used, the characteristics of the target plasticizer, the molecular weight, and the like. Generally, it is used at the ratio of 10-80 mass% of the said aliphatic dicarboxylic acid, 10-80 mass% of the said diol, and 1-50 mass% of the said aromatic monohydric alcohol.

When the aliphatic diol and the aromatic diol are used in combination as the diol, the molar ratio of the aromatic diol in the diol in the ester compound is 80% or less. And adjust the total amount so that it falls within the above range. When the above-mentioned aliphatic diol and the above-mentioned aromatic diol are used in combination as the above-mentioned diol, the obtained ester compound in the formula (1), A ¹ is an aliphatic dicarboxylic acid residue, and G ¹ is an aliphatic dicarboxylic acid. monoalcohol residues of (A ¹ -G ¹⁾ and A ¹ is an aliphatic dicarboxylic acid residue, G ¹ is the residue of an aromatic diol (A ¹ -G ¹⁾ randomly bonded.

Examples of the esterification catalyst include at least one metal or organometallic compound selected from the group consisting of Groups 2, 3, and 4 of the periodic table. Specific examples include: titanium, tin, zinc, aluminum, zirconium, magnesium, hafnium, germanium and other metals; titanium tetraisopropoxide, titanium tetra-n-butoxy titanium, and titanium alkoxides such as titanium acetone; Tin octanoate, 2-ethylhexanetin, zinc acetoacetone, zirconium tetrachloride, zirconium tetrachloride tetrahydrofuran complex, hafnium tetrachloride, hafnium tetrachloride tetrahydrofuran complex, germanium oxide, Metal compounds such as ethoxy germanium. From the viewpoints of reactivity, ease of operation, and storage stability of the ester compound obtained by the esterification reaction, titanium tetraisopropoxy titanium, tetra-n-butoxy titanium, and oxyacetamidine titanium are preferred. Alkoxides.

The esterification catalyst is preferably used in an amount of about 0.005 to 0.05 parts by mass relative to 100 parts by mass of the total amount of the aliphatic dicarboxylic acid, the diol, and the aromatic monohydric alcohol.

The modifier for a cellulose ester resin of the present invention includes the aforementioned ester compound, and is preferably composed of the aforementioned ester compound. In addition, as the modifier for the cellulose ester resin of the present invention, the product obtained by the above-mentioned production method may be used without purification. At this time, although not only the aforementioned ester compound, but also impurities other than the aforementioned ester compound (a polyester having a hydroxyl group at its terminal, which can be generated when the above-mentioned diol reacts with an aliphatic dicarboxylic acid, does not use the above-mentioned monohydric alcohol Polyesters such as capped carboxyl groups present at the end of the polyester), but do not particularly hinder the effect of the modifier.

Depending on the number average molecular weight and composition of the ester compound, the modifier for the cellulose ester resin of the present invention is liquid or solid.

2. Cellulose ester resin composition The cellulose ester resin composition of the present invention is a resin composition containing a cellulose ester resin and the aforementioned modifier for a cellulose ester resin. The cellulose ester resin composition of the present invention preferably contains about 3 to 30 parts by mass of the cellulose ester resin modifier, preferably about 4 to 25 parts by mass, and more preferably about 100 parts by mass of the cellulose ester resin. It contains about 5 to 20 parts by mass. If it is the resin composition of the composition of the said range, it can be set as the film excellent in transparency and moisture permeability resistance.

The aforementioned cellulose ester resin is mainly a mixed fatty acid ester (cellulose) of cellulose composed of cellulose acetate. There is no particular limitation on cellulose as a raw material of the cellulose trioxide, and examples thereof include cotton wool, wood pulp (derived from coniferous trees, derived from broadleaf trees), and kenaf. The cellulose esters obtained in this way can be mixed and used in any ratio. The most common industrial synthesis method of mixed fatty acid esters of cellulose is to use cellulose as a mixed organic acid containing fatty acids (acetic acid, propionic acid, valeric acid, etc.) corresponding to acetyl and other fluorenyl groups. A method of making ingredients tritium. In addition, as the cellulose halide, for example, L-20, L-30, L-50, L-70, LT-55 (manufactured by DAICEL Co., Ltd.), CA-394-60LF (manufactured by Eastman Chemical Co., Ltd.) And other commercially available items.

The cellulose ester resin composition of the present invention may contain other components within a range that does not hinder the effects of the present invention. Examples of the other components include additives other than the above-mentioned polyester-based modifiers, plasticizers, moisture-proofing agents, retardation expressing agents, ultraviolet absorbers, infrared absorbers, inorganic fine particles, and dyes. These additives may be those generally known.

3. Optical film The optical film of the present invention is a film containing the cellulose ester resin composition.

The optical film of the present invention can be obtained by molding the cellulose ester resin composition into a film shape. Examples of the molding method include a method in which the cellulose ester resin composition is melt-kneaded with an extruder or the like, and formed into a film shape using a T-die or the like. Further, it can also be obtained by a solution casting method in which the cellulose ester resin composition is uniformly dissolved and mixed in an organic solvent to obtain a resin solution, and the resin solution is cast on a support and dried. In the solution casting method, since the orientation of the aforementioned cellulose ester resin in the film during molding can be suppressed, the obtained film substantially exhibits optical isotropy. This thin film of display optics and the like can be used as a member of a liquid crystal display or the like as an optical film, and is useful as a polarizer protective film or an optical compensation film (for a liquid crystal display of an IPS driving method).

[Examples] Hereinafter, the present invention will be described in more detail by way of synthesis examples, examples, and comparative examples, but the scope of the present invention is not limited by these examples.

<Measurement method> (a) Acid value of ester compound In a conical flask, 60 g of THF / ethanol = 5/1 (mass ratio) solvent was placed. Phenolphthalein was added to the solvent as an indicator, and titration was performed with a 0.1 mol / l sodium hydroxide aqueous solution until a reddish color was confirmed. After weighing an arbitrary amount of the sample to completely dissolve it in the sample, titration was performed with a 0.1 mol / l sodium hydroxide aqueous solution until a reddish color was confirmed. The acid value was obtained from the titration result based on the following calculation formula.

[Equation 1] A: ml number of 0.1 mol / l sodium hydroxide aqueous solution required for titration of sample f: titration concentration of 0.1 mol / l sodium hydroxide aqueous solution S: g of sample

(b) Hydroxyl value of the ester compound 5 g of the sample was weighed and placed in an iodine bottle, and 5 ml of a mixed solution of pyridine / ester anhydride = 7/1 (mass ratio) was added, and an air cooling tube was installed. The iodine bottle was heated in a water bath for 1.5 hours, and then 5 ml of water was added from the top of the air-cooled tube, followed by heating for 10 minutes. After cooling to room temperature, rinse the inner wall of the air cooling tube with 50 ml of ethanol, and then remove the air cooling tube. Phenolphthalein was added as an indicator, and titration was performed with a 0.5 mol / l sodium hydroxide aqueous solution until reddish color was confirmed.

In addition, a blank test was performed by the same operation, and the hydroxyl value was obtained from the titration results based on the following calculation formula.

[Equation 2] A: Titration ml of 0.5mol / l sodium hydroxide aqueous solution in this test B: Titration ml of 0.5mol / l sodium hydroxide aqueous solution in blank test f: Titration concentration of 0.5mol / l sodium hydroxide aqueous solution S: Sample G number

(c) Number-average molecular weight of the ester compound A polystyrene having a known molecular weight was used as a standard substance and measured by GPC under the following conditions. Equipment: HLC-8320 (manufactured by Tosoh Corporation). Column: TSKgel SuperHZ3000 + TSKgel Super HZ2000 + TSKgel SuperHZ1000, one each in series Solvent: THF Flow rate: 0.3ml / min Detector: RI

(d) The composition ratio of the glycol residue or dicarboxylic acid residue of the ester compound is measured by ¹ H-NMR under the following conditions. Based on the peak intensity ratio of protons associated with each residue, Calculated using the method. Equipment: JNM-ECS-400 (manufactured by Japan Electronics Co., Ltd.) Solvent: deuterated chloroform

(e) Thickness of film The thickness of the film was measured using a micrometer (manufactured by QuantuMike Mitutoyo Co., Ltd.).

(f) The moisture permeability test piece and operation of the film are based on JIS Z0218. Among them, the temperature condition for the accelerated test is 50 ° C, and the value calculated using the calculation method described in JIS Z0218 is used as the measured value based on the difference in mass between the first and third hours of the test. The film is based on the following formula: The thickness was converted to a value of 80 μm as the moisture permeability.

[Equation 3] d: film thickness (μm) for testing P: measured value

(g) The transparency (haze) of the film is based on JIS K7136. Machine: HazeMeterNDH 4000 (manufactured by Nippon Denshoku Industries Co., Ltd.)

<Raw materials> Cellulose ester resin: cellulose acetate (LT-55 manufactured by DAICEL Co., Ltd.) Phosphate-based plasticizer 1: Triphenyl phosphate (TPP) Phosphate-based plasticizer 2: Biphenyldiphenyl Phenyl phosphate (BDP) ester compounds A to K: ester compounds synthesized in Examples and Comparative Examples described later

<Synthesis of Ester Compound> Example 1 Synthesis of Ester Compound A A 1 L glass four-necked round-bottomed flask equipped with a stirrer, a thermometer, and a distillation device was placed in 324 g (3.0 mol) of benzyl alcohol as an aromatic monohydric alcohol. 298 g (4.8 mol) of ethylene glycol as a glycol, 486 g (4.1 mol) of succinic acid as an aliphatic dicarboxylic acid, and 0.17 g of tetra-n-butyl titanate as a catalyst, then under normal pressure It took 7 hours to heat up to 160 ° C. The gas flowing out during the temperature rise is condensed by the rectification device, and is divided into water and other low-boiling substances generated in the reaction, and the water is recovered, and the other low-boiling substances are returned to the flask. After cooling until the gas stops flowing out, the rectification device is removed, and a round-bottomed flask is installed with a square tube, a cooling tube, and a 200 ml eggplant-shaped flask. The temperature is again raised to 200 ° C under normal pressure for 10 hours and maintained at 200 ° C for 7 hours. Thereafter, a pressure-reducing device was installed in the round-bottomed flask, and maintained at 180 to 200 ° C. for 2 hours under a reduced pressure of 33 kPa. The water produced by the reaction was recovered into a 200-ml eggplant-type flask during the period when the temperature was raised from normal pressure to a reduced pressure and maintained at a reduced temperature. After that, the pressure was reduced to 3 kPa, and the temperature was raised to 230 ° C. over 7.5 hours to perform polycondensation. As a result, 658 g of a yellow-brown solid with the following formula as a main component was obtained. The number average molecular weight of the ester compound A was 1200, the acid value was 0.12 mgKOH / g, and the hydroxyl value was 13.8 mgKOH / g.

[Chemical Formula 3]

Example 2 Synthesis of Ester Compound B In a 500-ml glass four-necked round-bottom flask equipped with a stirrer, a thermometer, and a rectifying device, 116 g (1.1 mol) of benzyl alcohol as an aromatic monohydric alcohol and 1 79 g (0.6 mol) of 4-benzenedimethanol and 87 g (1.1 mol) of 1,2-propanediol, 170 g (1.4 mol) of succinic acid as an aliphatic dicarboxylic acid, and tetra-n-butyl titanic acid as a catalyst After 0.06 g of the ester, the temperature was raised to 230 ° C. over 9 hours under normal pressure. The gas flowing out during the temperature rise is condensed by the rectification device, and is divided into water and other generated in the reaction. The water is recovered, and other low boiling materials are returned to the flask. After cooling until the gas stops flowing out, the rectification device is removed, and a round-bottomed flask is installed with a square tube, a cooling tube, and a 200ml eggplant-shaped flask, and it is heated to 230 ° C for 2 hours at normal pressure again and maintained at 230 ° C for 30 minutes. Thereafter, a pressure-reducing device was installed in the round-bottomed flask, and maintained at 160 to 180 ° C. for 2 hours under a reduced pressure of 13.3 kPa. The water produced by the reaction was recovered into a 200-ml eggplant-type flask during the period when the temperature was raised from normal pressure to a reduced pressure and maintained at a reduced temperature. After that, the pressure was reduced to 0.4 kPa, and the temperature was raised to 180 ° C. over 6.5 hours to perform polycondensation. As a result, 299 g of a yellow-brown transparent highly viscous liquid having the following formula as a main component was obtained. The number average molecular weight of the ester compound B is 1220, the acid value is 0.20 mgKOH / g, the hydroxyl value is 11.8 mgKOH / g, and the molar ratio of the 1,4-benzenedimethanol residue to the 1,2-propanediol residue is 4: 6.

[Chemical Formula 4]

Example 3 Synthesis of Ester Compound H In a 1 L glass four-necked round-bottomed flask equipped with a stirrer, a thermometer, and a distillation device, 242 g (1.8 mol) of 2-phenoxyethanol as an aromatic monohydric alcohol was placed as After 249 g (4.0 mol) of ethylene glycol, 322 g (2.7 mol) of succinic acid as an aliphatic dicarboxylic acid, and 0.11 g of tetra-n-butyl titanate as a catalyst, it takes 5 at normal pressure. The temperature rose to 225 ° C in one hour. The gas flowing out during the temperature rise is condensed by the rectification device, and is divided into water and other low-boiling substances generated in the reaction, and the water is recovered, and the other low-boiling substances are returned to the flask. After cooling until the gas stops flowing out, the rectification device is removed, and a round-bottomed flask is installed with a square tube, a cooling tube and a 200 ml eggplant-shaped flask, and the temperature is raised to 240 ° C. again under normal pressure for 3 hours. The water produced during the reaction was recovered into a 200 ml eggplant-type flask. Thereafter, a pressure reduction device was installed in the round bottom flask, and the pressure was reduced to 2.3 kPa, and the temperature was raised to 180 ° C. for 10 hours to perform polycondensation. As a result, 473 g of a light yellow solid having the following formula as a main component was obtained. The number average molecular weight of the ester compound H was 1150, the acid value was 0.05 mgKOH / g, and the hydroxyl value was 9.1 mgKOH / g.

[Chemical Formula 5]

Example 4 Synthesis of Ester Compound I In a 1-liter glass four-necked round-bottomed flask equipped with a stirrer, a thermometer, and a rectifying device, 391 g (2.8 mol) of 2-phenoxyethanol as an aromatic monohydric alcohol was placed, and After 302 g (3.4 mol) of 2-methyl-1,3-propanediol, 279 g (2.4 mol) of succinic acid as an aliphatic dicarboxylic acid, and 0.07 g of tetra-n-butyl titanate as a catalyst It took 3 hours to increase the temperature to 240 ° C under normal pressure. The gas flowing out during the temperature rise is condensed by the rectification device, and is divided into water and other low-boiling substances generated in the reaction, and the water is recovered, and the other low-boiling substances are returned to the flask. After cooling until the gas stops flowing out, the rectification device is removed, and a round-bottomed flask is installed with a square tube, a cooling tube, and a 200 ml eggplant-shaped flask, and it takes 3 hours to rise to 250 ° C. under normal pressure again. The water produced during the reaction was recovered into a 200 ml eggplant-type flask. Thereafter, a pressure reduction device was installed in the round bottom flask, and the pressure was reduced to 2.3 kPa, and the temperature was raised to 180 ° C. for 6 hours to perform polycondensation. As a result, 499 g of a yellow transparent liquid having the following formula as a main component was obtained. The number average molecular weight of the ester compound I was 1370, the acid value was 0.02 mgKOH / g, and the hydroxyl value was 13.7 mgKOH / g.

[Chemical Formula 6]

Example 5 Synthesis of Ester Compound J In a 1-liter glass four-necked round-bottomed flask equipped with a stirrer, a thermometer, and a distillation device, 262 g (1.9 mol) of 2-phenoxyethanol as an aromatic monohydric alcohol was placed as 247 g (3.3 mol) of 1,2-propanediol, 299 g (2.5 mol) of succinic acid as an aliphatic dicarboxylic acid, and 0.07 g of tetra-n-butyl titanate as a catalyst, under normal pressure It took 5 hours to heat up to 245 ° C. The gas flowing out during the temperature rise is condensed by the rectification device, and is divided into water and other low-boiling substances generated in the reaction, and the water is recovered, and the other low-boiling substances are returned to the flask. After cooling until the gas stops flowing, the rectification device is removed, and a round-bottomed flask is installed with a rectangular tube, a cooling tube, a 200ml eggplant-shaped flask, and a decompression device. After depressurizing to 2.3 kPa, it takes 4.5 hours to raise the temperature to 180 ° C to perform condensation . The water produced during the reaction was recovered into a 200 ml eggplant-type flask. As a result, 487 g of a yellow transparent liquid having the following formula as a main component was obtained. The number average molecular weight of the ester compound J was 1010, the acid value was 0.06 mgKOH / g, and the hydroxyl value was 12.7 mgKOH / g.

[Chemical Formula 7]

Comparative Example 1 Synthesis of ester compound C In a 1-liter glass four-necked round-bottomed flask equipped with a stirrer, a thermometer, and a rectifying device, 190 g (1.8 mol) of benzyl alcohol as an aromatic monohydric alcohol, and After 211 g (1.5 mol) of 4-benzyl alcohol, 232 g (2.0 mol) of succinic acid as an aliphatic dicarboxylic acid, and 0.07 g of tetra-n-butyl titanate as a catalyst, it took 11 at normal pressure The temperature rose to 210 ° C in one hour. The gas flowing out during the temperature rise is condensed by the rectification device, and is divided into water produced by the reaction and others. The water is recovered, and the rest is returned to the flask. Then, the rectification device was removed, and a round-bottomed flask was equipped with a sculpting tube, a cooling tube, a 200 ml eggplant-shaped flask, and a decompression device, and maintained at 160-190 ° C. for 12 hours under a reduced pressure of 13.3 kPa. The water produced by the reaction during the reduced pressure was recovered into a 200 ml eggplant-type flask. Thereafter, the pressure was reduced to 0.4 kPa, and the temperature was raised to 180 ° C. over 4.5 hours to perform polycondensation. As a result, 423 g of a yellow-brown solid with the following formula as a main component was obtained. The number average molecular weight of the ester compound C was 1,000, and the acid value was 0.29 mgKOH / g.

[Chemical Formula 8]

Comparative Example 2 Synthesis of Ester Compound D In a 1-liter glass four-necked round-bottomed flask equipped with a stirrer, a thermometer, and a rectification device, 590 g (6.6 mol) of 1,3-butanediol as a diol and After 292 g (2.0 mol) of adicarboxylic acid and 166 g (1.0 mol) of terephthalic acid, and 0.11 g of tetra-n-butyl titanate as a catalyst, the temperature was raised to 230 ° C. under normal pressure for 10 hours. . The gas flowing out during the temperature rise is condensed by the rectification device, and is divided into water produced by the reaction and others. The water is recovered, and the rest is returned to the flask. After cooling until the gas stops flowing out, the rectification device is removed, and a round-bottomed flask is installed with a square tube, a cooling tube, and a 200ml eggplant-shaped flask, and it is heated to 230 ° C under normal pressure again for 2 hours and maintained at 230 ° C for 16 hours. The water produced during the reaction was recovered into a 200 ml eggplant-type flask. Thereafter, a pressure reduction device was attached to the round-bottomed flask, and the pressure was reduced to 0.4 kPa, and the temperature was raised to 160 ° C. over 5.5 hours to perform polycondensation. After cooling, the temperature was returned to normal temperature, 177 g (1.7 mol) of acetic anhydride was added, and the temperature was maintained at 120 ° C for 4 hours. After that, the pressure was reduced to 2 kPa while maintaining 120 ° C, and low-boiling matter was recovered. As a result, 727 g of a yellow-brown transparent liquid having the following formula as a main component was obtained. The number average molecular weight of the ester compound D was 1300, the acid value was 0.44 mgKOH / g, the hydroxyl value was 0.24 mgKOH / g, and the molar ratio of the adipic acid residue to the terephthalic acid residue was 2: 1.

[Chemical Formula 9]

Comparative Example 3 Synthesis of Ester Compound E In a 1-liter glass four-necked round-bottomed flask equipped with a stirrer, a thermometer, and a rectification device, 367 g (4.8 mol) of 1,2-propanediol as a glycol and a dicarboxylic acid were placed. After 461 g (3.2 mol) of adipic acid and 0.13 g of tetra-n-butyl titanate as a catalyst, the temperature was raised to 180 ° C. under normal pressure in 7.5 hours. The gas flowing out during the temperature rise is condensed by the rectification device, and is divided into water produced by the reaction and others. The water is recovered, and the rest is returned to the flask. Then, the rectification device was removed, and a round-bottomed flask, a cooling tube, a 200 ml eggplant-shaped flask, and a decompression device were installed. The pressure was reduced to 0.7 kPa while the temperature was raised to 180 ° C. to perform the polycondensation. After cooling, the temperature was returned to normal temperature, 204 g (2.0 mol) of acetic anhydride was added, and the temperature was maintained at 120 ° C for 4 hours. After that, the pressure was reduced to 1.3 kPa while maintaining 120 ° C, and low-boiling matter was recovered. As a result, 697 g of a light yellow transparent liquid having the following formula as a main component was obtained. The number average molecular weight of the ester compound E was 1400, the acid value was 0.20 mgKOH / g, and the hydroxyl value was 0.10 mgKOH / g.

[Chemical Formula 10]

Comparative Example 4 Synthesis of Ester Compound F In a 1-liter glass four-necked round-bottomed flask equipped with a stirrer, a thermometer, and a rectification device, 365 g (4.8 mol) of 1,2-propanediol as a glycol and a dicarboxylic acid were placed. After 467 g (3.2 mol) of adipic acid and 0.13 g of tetra-n-butyl titanate as a catalyst, the temperature was raised to 180 ° C. over 4 hours under normal pressure. The gas flowing out during the temperature rise is condensed by the rectification device, and is divided into water produced by the reaction and others. The water is recovered, and the rest is returned to the flask. After cooling until the gas stopped flowing out, the rectification device was removed, and a round-bottomed flask was fitted with a square tube, a cooling tube, and a 200 ml eggplant-shaped flask, and kept at 180 ° C. for 4 hours. Thereafter, a pressure-reducing device was installed in the round-bottomed flask, and it was maintained at 170 to 180 ° C. for 11 hours under a reduced pressure of 10.6 kPa. The water produced during the reaction was recovered into a 200 ml eggplant-type flask. Thereafter, it was decompressed to 0.7 kPa while taking pressure for 11.5 hours, and heated to 180 ° C. to perform polycondensation. As a result, 591 g of a colorless transparent liquid having the following formula as a main component was obtained. The number average molecular weight of the ester compound F was 1500, the acid value was 0.36 mgKOH / g, and the hydroxyl value was 108 mgKOH / g.

[Chemical Formula 11]

Comparative Example 5 Synthesis of Ester Compound G In a 500-ml glass four-necked round-bottomed flask equipped with a stirrer, a thermometer, and a rectification device, 301 g (4.0 mol) of 1,2-propanediol as a glycol was placed as an aromatic monomer. 122 g (1.0 mol) of benzoic acid as carboxylic acid, 8 g (0.05 mol) of adipic acid as dicarboxylic acid and 24 g (0.2 mol) of phthalic anhydride, and tetra-n-butyl titanate 0.04 as catalyst After g, the temperature was raised to 200 ° C. under normal pressure in 6.5 hours. The gas flowing out during the temperature rise is condensed by the rectification device, and is divided into water produced by the reaction and others. The water is recovered, and the rest is returned to the flask. Then, the rectification device was removed, and a round-bottomed flask was equipped with a stern tube, a cooling tube, a 200 ml eggplant-shaped flask, and a decompression device, and maintained at 150 to 160 ° C. for 18 hours under a reduced pressure of 24.0 kPa. The water produced by the reaction during the reduced pressure was recovered into a 200 ml eggplant-type flask. After that, it took 8 hours to reduce the pressure to 0.7 kPa and raised the temperature to 180 ° C. to perform polycondensation. As a result, 152 g of a yellow transparent liquid having the following formula as a main component was obtained. The number average molecular weight of the ester compound G was 410, the acid value was 0.29 mgKOH / g, the hydroxyl value was 14.1 mgKOH / g, and the molar ratio of the adipic acid residue to the phthalic acid residue was 1: 3.

[Chemical Formula 12]

Comparative Example 6 Synthesis of Ester Compound K According to the method described in International Publication No. 10/087219, ethylene glycol and 1,2-propylene glycol as glycols, succinic acid and terephthalic acid as dicarboxylic acids were prepared. And acetic anhydride was reacted to obtain a pale yellow transparent liquid having the following formula as a main component. The number average molecular weight of the ester compound K is 1030 (average degree of polymerization n = 5.0), the acid value is 0.42 mgKOH / g, the hydroxyl value is 1.97 mgKOH / g, the moles of ethylene glycol residues and 1,2-propylene glycol residues The ratio is 1: 1 and the molar ratio of the succinic acid residue to the terephthalic acid residue is 1: 1.

[Chemical Formula 13]

<Formation and Evaluation of Film> Example 11 A solution prepared by dissolving 2.14 g of cellulose ester resin and 0.26 g of ester compound A in a mixed solvent of 34.0 g of methylene chloride, 4.8 g of methanol, and 1.2 g of butanol was weighed out. 5g was placed in a petri dish with a diameter of 94mm. After the lid was closed, the solution was cast to the entire petri dish. Thereafter, it was left standing at room temperature for a while, and then dried at 50 ° C for 0.5 hour, and then dried at 100 ° C for 1 hour, thereby obtaining a film having a thickness of 25 µm. Table 1 shows the results of measuring the moisture permeability and transparency of the obtained film by the aforementioned method.

Example 12 A film having a thickness of 27 μm was obtained in the same manner as in Example 1 except that the ester compound B was used instead of the ester compound A. Table 1 shows the results of measuring the moisture permeability and transparency of the obtained film by the aforementioned method.

Example 13 A thin film having a thickness of 26 μm was obtained in the same manner as in Example 1 except that the ester compound H was used instead of the ester compound A. Table 1 shows the results of measuring the moisture permeability and transparency of the obtained film by the aforementioned method.

Example 14 The same operation as in Example 1 was performed except that the ester compound I was used instead of the ester compound A to obtain a film having a thickness of 28 μm. Table 1 shows the results of measuring the moisture permeability and transparency of the obtained film by the aforementioned method.

Example 15 A film having a thickness of 25 μm was obtained in the same manner as in Example 1 except that the ester compound J was used instead of the ester compound A. Table 1 shows the results of measuring the moisture permeability and transparency of the obtained film by the aforementioned method.

Comparative Example 11 The same operation as in Example 1 was performed except that the ester compound C was used instead of the ester compound A to obtain a film having a thickness of 28 μm. Table 1 shows the results of measuring the moisture permeability and transparency of the obtained film by the aforementioned method.

Comparative Example 12 A thin film having a thickness of 26 μm was obtained in the same manner as in Example 1 except that the ester compound D was used instead of the ester compound A. Table 1 shows the results of measuring the moisture permeability and transparency of the obtained film by the aforementioned method.

Comparative Example 13 A thin film having a thickness of 26 μm was obtained in the same manner as in Example 1 except that the ester compound E was used instead of the ester compound A. Table 1 shows the results of measuring the moisture permeability and transparency of the obtained film by the aforementioned method.

Comparative Example 14 A film having a thickness of 25 μm was obtained in the same manner as in Example 1 except that the ester compound F was used instead of the ester compound A. Table 1 shows the results of measuring the moisture permeability and transparency of the obtained film by the aforementioned method.

Comparative Example 15 A film having a thickness of 28 μm was obtained in the same manner as in Example 1 except that the ester compound G was used instead of the ester compound A. Table 1 shows the results of measuring the moisture permeability and transparency of the obtained film by the aforementioned method.

Comparative Example 16 A film having a thickness of 25 μm was obtained in the same manner as in Example 1 except that the phosphate compound 1 was used instead of the ester compound A. Table 1 shows the results of measuring the moisture permeability and transparency of the obtained film by the aforementioned method.

Comparative Example 17 A film having a thickness of 24 μm was obtained in the same manner as in Example 1 except that the phosphate compound 2 was used instead of the ester compound A. Table 1 shows the results of measuring the moisture permeability and transparency of the obtained film by the aforementioned method.

Comparative Example 18 A thin film having a thickness of 24 μm was obtained in the same manner as in Example 1 except that the ester compound A was not used. Table 1 shows the results of measuring the moisture permeability and transparency of the obtained film by the aforementioned method.

Comparative Example 19 A thin film having a thickness of 26 μm was obtained in the same manner as in Example 1 except that the ester compound K was used instead of the ester compound A. Table 1 shows the results of measuring the moisture permeability and transparency of the obtained film by the aforementioned method.

[Table 1] * EG: ethylene glycol, 1,2-PG: 1,2-propanediol BDM: 1,4-benzenedimethanol, 1,3-BG: 1,3-butanediol

It can be seen that the films containing the ester compound terminated with an aromatic monohydric alcohol as in Examples 11 to 15 and Comparative Example 11 were not performed as the ester compounds terminated with acetic anhydride as in Comparative Examples 12, 13 and 19, and Comparative Example 14. Compared with the blocked ester compound, the ester compound capped with benzoic acid as in Comparative Example 15, or the films containing phosphate ester plasticizers used in Comparative Examples 16 and 17 as compared, the apparent moisture permeability is significantly lower, Improved moisture permeability. In addition, it was found that the film of Comparative Example 11 containing an ester compound containing only an diol as an aromatic diol and terminated with an aromatic monohydric alcohol had a low water vapor transmission rate but poor transparency (haze value). As described above, it is found that by including the ester compound of the composition of the present invention as a modifier, the transparency of the film can be maintained and the moisture permeability resistance can be improved.

Claims (10)

A modifier for a cellulose ester resin, comprising an ester compound represented by the following formula (1): [Chemical Formula 1] [In formula (1), A ¹ and A ² represent the same or different aliphatic dicarboxylic acid residues; G ¹ represents a glycol residue, and the aforementioned glycol residue is an aliphatic glycol residue, or A combination of an aliphatic diol residue and an aromatic diol residue; M ¹ and M ² represent the same or different aromatic monohydric alcohol residues; n is an integer of 1 or more]. For example, the modifier for a cellulose ester resin according to claim 1, wherein the number average molecular weight of the aforementioned ester compound is 500-2500. The modifier for a cellulose ester resin according to claim 1 or 2, wherein the aforementioned M ¹ and M ² are selected from the group consisting of phenol, 2-cresol, 3-cresol, 4-cresol, benzyl alcohol, 2- At least one aromatic monohydric alcohol in the group consisting of methylbenzyl alcohol, 3-methylbenzyl alcohol, 4-methylbenzyl alcohol, 1-phenylethanol, 2-phenylethanol, 2-benzyloxyethanol, and 2-phenoxyethanol Residues. The modifier for a cellulose ester resin according to claim 3, wherein the aforementioned M ¹ and M ² are at least one aromatic monohydric alcohol selected from the group consisting of 2-benzyloxyethanol and 2-phenoxyethanol Residues. The modifier for a cellulose ester resin according to any one of claims 1 to 4, wherein the aforementioned G ¹ is the aforementioned aliphatic diol residue. The modifier for a cellulose ester resin according to any one of claims 1 to 4, wherein the aforementioned G ¹ is a combination of the aforementioned aliphatic diol residue and aromatic diol residue, and the aforementioned ester compound in the aforementioned two The molar ratio of the aromatic diol residue in the diol residue is 80% or less. The modifier for a cellulose ester resin according to any one of claims 1 to 6, wherein the hydroxyl value of the aforementioned ester compound is 30 mgKOH / g or less. The modifier for a cellulose ester resin according to any one of claims 1 to 7, wherein the acid value of the aforementioned ester compound is 3 mgKOH / g or less. A cellulose ester resin composition comprising the modifier for a cellulose ester resin according to any one of claims 1 to 8 and a cellulose ester resin. An optical film comprising the cellulose ester resin composition as claimed in claim 9.