TWI760340B - Modifier for cellulose ester resin, cellulose ester resin composition and optical film - Google Patents

Abstract

[式(1)中，A¹ 及A² 表示相同或不同之脂肪族二羧酸殘基。G¹ 表示二元醇殘基，前述二元醇殘基為脂肪族二元醇殘基、或脂肪族二元醇殘基及芳香族二元醇殘基之組合。M¹ 及M² 表示相同或不同之芳香族一元醇殘基。n為1以上整數]。An object of the present invention is to provide a modifier which imparts excellent moisture permeability resistance to a cellulose ester resin and does not inhibit the transparency inherent in the cellulose ester resin. A modifier for cellulose ester resin, comprising an ester compound represented by the following 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].

Description

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

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

Background Art Conventionally, cellulose ester resins have been used as photographic supports because of their toughness and transparency. Cellulose ester resin not only has high optical transparency, but also has high optical isotropic properties, so in recent years, it has been used as an optical material for devices that use polarized light such as liquid crystal displays, and is used as a protective film for polarizers, Supports such as optical compensation films optimized for display when viewed from an oblique direction.

When a film composed of the above-mentioned cellulose ester resin is used as a protective film for a polarizer used in a polarizing plate of a liquid crystal display member, the cellulose ester film cannot sufficiently prevent the intrusion of moisture such as moisture, so there is a possibility of deterioration of the polarizer, Problems such as peeling between the polarizer and the protective film. Therefore, a plasticizer such as triphenyl phosphate was previously added to a cellulose ester resin, and a film to which moisture permeability resistance was imparted was used as a polarizer protective film.

In recent years, the demand for thinning of liquid crystal displays is increasing. With the thinning of liquid crystal displays, the thinning of the polarizer protective film is 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 resistance is significantly reduced. In order to obtain sufficient moisture permeability resistance, it is considered to increase the amount of the aforementioned plasticizer, but in this case, problems such as bleeding of the plasticizer and reduction in the strength of the film itself may occur. Although it has also been proposed to improve the moisture permeability resistance of the film by adding a polymer (polyester or polyetherester) having a weight average molecular weight in a specific range to the cellulose ester resin (Patent Document 1), 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 lower number 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 lower number diol. Patent Document 4 describes a polyester terminated with an ether alcohol in a condensate of a polybasic acid containing a specific amount of an aromatic dicarboxylic acid and a polyhydric alcohol. Patent Document 5 describes polyesters of condensates of aromatic dicarboxylic acids and diols. 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 lower number diol. However, the moisture permeability resistance of the films formed using the modifiers and cellulose ester resins described in Patent Documents 2 to 6 cannot be said to be sufficient, and other additives (moisture-proofing agents) are required. Therefore, polyester-based modifiers that can impart excellent moisture permeability resistance to cellulose ester resins are desired.

Prior Art Document Patent Document 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 5: Japanese Patent Laid-Open Publication 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 cellulose ester resin and does not inhibit the transparency inherent in cellulose ester resin. Another object of the present invention is to provide a cellulose ester resin composition containing the modifier, and a cellulose ester resin film for optics produced from the resin composition excellent in moisture permeability resistance and transparency.

MEANS TO SOLVE THE PROBLEM The present inventors have devoted themselves to researches to develop a modifier which imparts excellent moisture permeability resistance to cellulose ester resin and does not hinder the inherent transparency of cellulose ester resin. The above-mentioned problems 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 the modifier for cellulose ester resin, the cellulose ester resin composition, and the optical film shown in the following items 1 to 10.

Item 1. A modifier for 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 cellulose ester resin according to Item 1, wherein the ester compound has a number average molecular weight of 500 to 2,500. Item 3. The modifier for 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-phenethyl alcohol, 2-phenylethyl alcohol, 2-benzyloxyethyl alcohol and at least one kind of aroma from the group consisting of 2-phenoxyethyl alcohol Residues of monohydric alcohols. Item 4. The modifier for cellulose ester resin according to Item 3, wherein M ¹ and M ² are at least one kind of aroma selected from the group consisting of 2-benzyloxyethanol and 2-phenoxyethanol Residues of monohydric alcohols. Item 5. The modifier for cellulose ester resin according to any one of Items 1 to 4, wherein the G ¹ is the aliphatic diol residue. Item 6. The modifier for cellulose ester resin according to any one of Items 1 to 4, wherein G ¹ is a combination of the aliphatic diol residue and aromatic diol residue, and the ester compound The molar ratio of the above-mentioned aromatic diol residues in the above-mentioned diol residues is 80% or less. Item 7. The modifier for 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 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 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.

Effects of the 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 inhibit the transparency inherent in the cellulose ester resin. By adding the modifier for cellulose ester resin of the present invention to the cellulose ester resin, it is possible to impart excellent transparency and Moisture permeation resistance.

Modes for Carrying Out the Invention The modifier for cellulose ester resin, the cellulose ester resin composition, and the 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 contains 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 said ester compound is a reaction product of an aliphatic dicarboxylic acid, a dihydric alcohol, and an aromatic monohydric alcohol. That is, the above-mentioned ester compound has both terminal carboxylic acids of polyester (polymer having repeating units based on aliphatic dicarboxylic acid and diol) obtained by esterification reaction of aliphatic dicarboxylic acid and diol. Aromatic monohydric alcohol-terminated structure.

When the modifier for cellulose ester resin of the present invention contains the aforementioned ester compound, the transparency and penetration resistance of the optical film obtained from the cellulose ester resin composition containing the modifier and the cellulose ester resin can be significantly improved wetness.

Here, the aliphatic dicarboxylic acid residue refers to a group remaining after removing a hydroxyl group from each of the two carboxyl groups which the aliphatic dicarboxylic acid has. The diol residue refers to a group remaining after hydrogen is removed from the two hydroxyl groups of the diol. The aromatic monohydric alcohol residue refers to a group remaining after removing hydrogen from the hydroxyl group of the aromatic monohydric alcohol.

The aliphatic dicarboxylic acid that forms the aliphatic dicarboxylic acid residues represented by A ¹ and A ² of 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 particularly preferably 2 to 4.

Specific examples of the aforementioned aliphatic dicarboxylic acids include oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, and 3-ethyl-3-methyl. 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, etc.

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, especially oxalic acid, malonic acid and succinic acid.

Carboxylic acid derivatives such as esters, acid chlorides, and acid anhydrides are included in the aforementioned aliphatic dicarboxylic acids. The aforementioned aliphatic dicarboxylic acids may be used alone or in combination of two or more.

An aliphatic diol residue is included in the diol residue represented by G ¹ of the above formula (1). Since the aliphatic diol residue is contained in the modifier, the compatibility with the cellulose ester resin is improved, so that the transparency of the obtained film can be maintained. As the diol that forms the diol residue represented by G ¹ of the above formula (1) by reaction, only aliphatic diol may be used, or aliphatic diol and aromatic diol may be used in combination use later. It is especially preferable to use only aliphatic diols.

The aforementioned aliphatic diol may be linear or branched, or may have an alicyclic structure. The number of carbon atoms in the aliphatic diol is preferably 2-15, preferably 2-6, particularly preferably 2-4.

As said aliphatic diol, ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-methyl-1,3-propanediol, ,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, 1,1-cyclohexanediethanol, etc.

Among these aliphatic diols, ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 1,2-butanediol, 1,2-propanediol, 3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-cyclohexanediol and 1,4-cyclohexanediol, especially ethylene glycol, 1,2 -Propanediol and 2-methyl-1,3-propanediol.

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

The said aromatic diol means the compound which has at least 2 aromatic ring structures in a molecule|numerator, and has 2 hydroxyl groups. The hydroxyl group in the compound may be directly bonded to the aromatic ring, or may be bonded to 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, particularly preferably 6 to 10.

As said aromatic diol, hydrogen roll, resorcinol, 2,2'-biphenol, 4,4'-biphenol, 2,2-bis(4-hydroxybenzene are mentioned, for example yl) 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-benzenediol Ethanol, 1,4-benzenediethanol and 2,2'-(1,3-phenylene)bis(2-propanol), etc.

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

When the diol residue represented by ^G1 is a combination of an aliphatic diol residue and an aromatic diol residue, the aromatic diol residue in the diol residue in the ester compound The molar ratio is preferably 80% or less, preferably 70% or less, and particularly preferably 60% or less.

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

The aromatic monohydric alcohol that forms the aromatic monohydric alcohol residues represented by M ¹ and M ² of the above formula (1) by reaction means a compound having at least one aromatic ring structure and one hydroxyl group in the molecule. By including the aromatic monohydric alcohol residue in the modifier, the moisture permeability resistance of the obtained film can be improved. The aromatic monohydric alcohol functions as a capping agent for the 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. The preferred form of the aforementioned aromatic monohydric alcohol is that the hydroxyl group is bonded to an alkyl group, an alkoxy group or an alkoxyalkyl group bonded to an aromatic ring, and the optimum form is that a hydroxyl group is bonded to an alkoxy group bonded to an aromatic ring. . The number of carbon atoms of the aforementioned aromatic monohydric alcohol is preferably 6-20, preferably 7-15, particularly preferably 8-10.

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-propanol, 4-propanol , 2,3,5-Tricresol, 2,3,6-Tricresol, 2,4,6-Tricresol, 1-Naphthol, 2-Naphthol, 2-Phenylphenol and 4-Phenylphenol, etc. Aromatic monohydric alcohol whose hydroxyl group is directly bonded to the 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-phenethyl alcohol, 2-phenethyl alcohol, 3-phenyl-1-propanol, 1-phenoxy-2- Aromatic monohydric alcohols in which hydroxyl groups such as propanol, 2-benzyloxyethanol, and 2-phenoxyethanol are bonded to other substituents bonded to the aromatic ring.

Among these aromatic monohydric alcohols, preferred are phenol, 2-cresol, 3-cresol, 4-cresol, 2-ethylphenol, 3-ethylphenol, 4-ethylphenol, 4-propanol, and benzyl Alcohol, 2-methylbenzyl alcohol, 3-methylbenzyl alcohol, 4-methylbenzyl alcohol, 2-ethylbenzyl alcohol, 3-ethylbenzyl alcohol, 4-ethylbenzyl alcohol, 4-isopropylbenzyl alcohol, 1-phenylethyl alcohol, 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-phenethyl alcohol, 2-phenethyl alcohol, 2-benzyloxyethyl alcohol and 2-phenoxyethyl alcohol Ethanol, particularly preferably benzyl alcohol, 2-methylbenzyl alcohol, 3-methylbenzyl alcohol, 4-methylbenzyl alcohol, 1-phenethyl alcohol, 2-phenethyl alcohol, 2-benzyloxyethanol and 2-phenoxyethanol, most preferably For 2-benzyloxyethanol and 2-phenoxyethanol.

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

n represents the number of repeating units. n is an integer of 1 or more, usually 1 to 20, preferably 2 to 15, more preferably 3 to 10. Within the above range, compatibility with the cellulose ester resin is excellent, and the effect of imparting plasticity is also excellent.

The number average molecular weight of the aforementioned ester compound is preferably 500-2500, preferably 700-2000, particularly preferably 800-1800. If the number-average molecular weight of the aforementioned ester compound is in the above-mentioned range, the modifier for cellulose ester resin is excellent in bleed-out resistance even under high temperature and high humidity, and is not easily volatile even under high temperature conditions such as in the film production process, so that it is possible to suppress and improve the Pollution of equipment and operating environment in manufacturing steps. In addition, the so-called number average molecular weight is a value measured by gel permeation chromatography (GPC) converted to polystyrene using tetrahydrofuran (THF) as an eluent. The detailed measurement conditions are described in Examples.

The acid value of the above-mentioned ester compound is derived from the carboxyl group present at the terminal of the polyester which can be formed when the diol and the aliphatic dicarboxylic acid are reacted, and the carboxyl group which is not terminated by the above-mentioned aromatic monohydric alcohol. In terms of imparting excellent moisture permeability resistance to the film and maintaining the stability of the modifying agent for cellulose ester resin itself, the content of the polyester having a carboxyl group at the terminal contained in the modifying agent for cellulose ester resin should be as small as possible Possibly less. Therefore, the optimum value of the acid value is 0, but even when there is an acid value, the effect of the present invention can be sufficiently exhibited as long as it is in the range shown below. The upper limit in the case of 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. When the acid value is present, the lower limit is preferably about 0.005 mgKOH/g.

The hydroxyl value of the above-mentioned ester compound is derived from the hydroxyl group present at the terminal of the polyester which can be formed when the diol reacts with the aliphatic dicarboxylic acid; it is derived from the unreacted hydroxyl group of the used diol, and the like. Since the hydroxyl group has a strong affinity with water, in order to maintain the moisture permeability resistance of the obtained film, the hydroxyl group is preferably less. The optimum value of the hydroxyl value is 0, but even when there is a hydroxyl value, the effect of the present invention can be sufficiently exhibited as long as it is within the range shown below. The upper limit in the case of having a hydroxyl value is preferably 30 mgKOH/g or less, preferably 25 mgKOH/g, and particularly preferably 15 mgKOH/g or less. The lower limit is preferably about 0.1 mgKOH/g when the hydroxyl value is present.

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

The aforementioned aliphatic dicarboxylic acid, the aforementioned dihydric alcohol, and the aforementioned aromatic monohydric alcohol can be used, respectively. The ratio of the above-mentioned components used in the production can be changed according to the types of components used, the characteristics of the intended plasticizer, the molecular weight, and the like. Generally, it is used in the ratio of the said aliphatic dicarboxylic acid 10-80 mass %, the said dihydric alcohol 10-80 mass %, and the said aromatic monohydric alcohol 1-50 mass %.

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 set to be in the range of 80% or less , and the total amount is adjusted appropriately 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 is in the formula (1) where A ¹ is an aliphatic dicarboxylic acid residue, and G ¹ is an aliphatic dicarboxylic acid residue. (A ¹ -G ¹ ) of alcohol residues and (A ¹ -G ¹ ) where A ¹ is an aliphatic dicarboxylic acid residue and G ¹ is an aromatic diol residue are randomly bonded.

As said esterification catalyst, at least 1 sort(s) of metal or organometallic compound chosen from the group which consists of Group 2, Group 3, and Group 4 of the periodic table can be mentioned. Specifically, metals such as titanium, tin, zinc, aluminum, zirconium, magnesium, hafnium, and germanium; titanium alkoxides such as titanium tetraisopropoxide, titanium tetra-n-butoxide, titanium oxyacetylacetone, etc.; Tin octanoate, tin 2-ethylhexane, zinc acetylacetonate, zirconium tetrachloride, zirconium tetrachloride tetrahydrofuran complex, hafnium tetrachloride, hafnium tetrachloride tetrahydrofuran complex, germanium oxide, tetrahydrofuran Metal compounds such as germanium ethoxide, etc. Titanium such as tetraisopropoxide titanium, tetra-n-butoxide titanium, titanium oxyacetylacetone, etc. is preferred in terms of reactivity, ease of handling, storage stability of the ester compound obtained by the esterification reaction, etc. Alkoxides.

It is preferable to use about 0.005-0.05 mass part of the said esterification catalyst with respect to 100 mass parts of total amounts of the said aliphatic dicarboxylic acid, the said dihydric alcohol, and the said aromatic monohydric alcohol.

The modifier for cellulose ester resin of this invention contains the said ester compound, Preferably it consists of the said ester compound. In addition, as the modifier for cellulose ester resin of the present invention, the product obtained by the above-mentioned production method may be used without purification. In this case, not only the above-mentioned ester compound but also impurities other than the above-mentioned ester compound (polyester having a hydroxyl group at the terminal, which can be produced when the above-mentioned diol and aliphatic dicarboxylic acid are reacted, are not treated by the above-mentioned monohydric alcohol) are included. The end-capping of carboxyl groups present at the end of the polyester, etc.), but does not particularly hinder the effect of the modifier.

The modifier for cellulose ester resin of the present invention is liquid or solid depending on the number-average molecular weight and composition of the constituent ester compound.

2. Cellulose ester resin composition The cellulose ester resin composition of the present invention is a resin composition comprising the cellulose ester resin and the aforementioned modifier for the cellulose ester resin. The cellulose ester resin composition of the present invention preferably contains about 3 to 30 parts by mass, preferably about 4 to 25 parts by mass, preferably about 4 to 25 parts by mass, relative to 100 parts by mass of the cellulose ester resin. To contain about 5-20 mass parts. A resin composition having a composition within the above range can be formed into a film having excellent transparency and moisture permeability resistance.

The aforementioned cellulose ester resin is mainly a mixed fatty acid ester (cellulose acylate) of cellulose composed of cellulose acetate. The cellulose as a raw material of the cellulose acylate is not particularly limited, and examples thereof include cotton linters, wood pulp (derived from conifers and broadleaf trees), and kenaf. In addition, the cellulose esters obtained in this way can be mixed and used in arbitrary ratios, respectively. The most common industrial synthesis method of mixed fatty acid esters of cellulose is to combine cellulose with mixed organic acids containing fatty acids (acetic acid, propionic acid, valeric acid, etc.) corresponding to acetyl groups and other acyl groups or their anhydrides. A method for the acidification of ingredients. In addition, as cellulose acylate, for example, L-20, L-30, L-50, L-70, LT-55 (manufactured by DAICEL Co., Ltd.), and CA-394-60LF (manufactured by EASTMAN Chemical Co., Ltd.) can also be used. and other commercially available products.

The cellulose ester resin composition of the present invention may contain other components as long as the effects of the present invention are not inhibited. Examples of other components include additives such as polyester-based modifiers other than the above, plasticizers, moisture-proofing agents, retardation expressing agents, ultraviolet absorbers, infrared absorbers, inorganic fine particles, and dyes. As these additives, well-known ones commonly used can be used.

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

The optical film of the present invention can be obtained by molding the aforementioned cellulose ester resin composition into a film. As a shaping|molding method, the method of melt-kneading the said cellulose ester resin composition with an extruder etc., and shaping|molding into a film shape using a T-die etc. is mentioned, for example. In addition, it can also be obtained by a solution casting method of uniformly dissolving and mixing the aforementioned cellulose ester resin composition in an organic solvent to obtain a resin solution, casting and drying the resin solution on a support. In the case of the solution casting method, since the alignment of the cellulose ester resin in the film in the process of forming can be suppressed, the obtained film exhibits substantially optical isotropy. This optically isotropic film can be used as an optical film as a member of a liquid crystal display or the like, and is useful as a polarizer protective film or an optical compensation film (for an IPS-driven liquid crystal display).

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

<Measuring method> (a) Acid value of ester compound In an Erlenmeyer flask, 60 g of a solvent of THF/ethanol=5/1 (mass ratio) was put. Phenolphthalein was added to the solvent as an indicator, and titration was performed with a 0.1 mol/l aqueous sodium hydroxide solution until a reddish color was confirmed. An arbitrary amount of the sample was weighed and completely dissolved therein, and then titrated with a 0.1 mol/l aqueous sodium hydroxide solution until a reddish color was confirmed. The acid value was calculated|required based on the following calculation formula from the titration result.

A：滴定試料所需之0.1mol/l氫氧化鈉水溶液之ml數 f：0.1mol/l氫氧化鈉水溶液之滴定濃度 S：試料之g數[Formula 1]

A: The number of ml of 0.1mol/l sodium hydroxide aqueous solution required for titrating the sample f: The titration concentration of the 0.1mol/l sodium hydroxide aqueous solution S: The number of grams of the sample

(b) Hydroxyl value of ester compound Weigh 5 g of the sample into an iodine bottle, add 5 ml of a mixed solution of pyridine/ester acid anhydride = 7/1 (mass ratio), and install an air cooling tube. The iodine bottle was heated in a water bath for 1.5 hours, after which 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 carried out with a 0.5 mol/l aqueous sodium hydroxide solution until a reddish color was confirmed.

In addition, a blank test was performed by the same operation, and the hydroxyl value was calculated|required based on the following calculation formula from the isotitration result.

A：本試驗中0.5mol/l氫氧化鈉水溶液之滴定ml數 B：空白試驗中0.5mol/l氫氧化鈉水溶液之滴定ml數 f：0.5mol/l氫氧化鈉水溶液之滴定濃度 S：試料之g數[Equation 2]

A: The titrated ml of 0.5 mol/l sodium hydroxide aqueous solution in this test B: The titrated ml of 0.5 mol/l sodium hydroxide aqueous solution in the blank test f: The titrated concentration of 0.5 mol/l sodium hydroxide aqueous solution S: Sample the number of g

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

(d) The composition ratio of the diol residue or the dicarboxylic acid residue of the ester compound was measured by ¹ H-NMR under the following conditions, based on the peak intensity ratio of the protons associated with each residue, by the usual Calculated using the method used. Machine used: JNM-ECS-400 (manufactured by JEOL 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) Moisture permeability of film The test piece and operation were in accordance with JIS Z0218. Among them, the temperature condition of the accelerated test was 50°C, and the value calculated by the calculation method described in JIS Z0218 based on the mass difference of the moisture permeable cup at the first hour and the third hour after the start of the test was used as the measured value, and the film was calculated according to the following formula. The value of the thickness converted to 80 μm was used as the moisture permeability.

d：用於試驗之薄膜厚度(μm) P：實測值

[Equation 3]

d: Thickness of the film used for the test (μm) P: Measured value

(g) Transparency (haze) of film Based on JIS K7136. Machine used: HazeMeterNDH 4000 (manufactured by Nippon Denshoku Kogyo Co., Ltd.)

<Material used> Cellulose ester resin: Cellulose acetate (LT-55 manufactured by DAICEL Co., Ltd.) Phosphate ester plasticizer 1: Triphenyl phosphate (TPP) Phosphate ester plasticizer 2: Biphenyl diphenyl Phenyl Phosphate (BDP) Ester Compounds A~K: Ester Compounds Synthesized in Examples and Comparative Examples to Be Described Later

<Synthesis of Ester Compound> Example 1 Synthesis of Ester Compound A In a 1-L glass four-neck round-bottom flask equipped with a stirrer, a thermometer, and a rectifying apparatus, 324 g (3.0 mol) of benzyl alcohol as an aromatic monohydric alcohol, After 298 g (4.8 mol) of ethylene glycol as a diol, 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, under normal pressure The temperature was raised to 160°C over 7 hours. The gas flowing out during the temperature rise is condensed by the rectification device, and divided into water and other low-boiling substances produced by the reaction, the water is recovered, and the other low-boiling substances are returned to the flask. After cooling until the gas stopped flowing out, the rectification device was dismantled, the round-bottomed flask was installed with a pipe, a cooling pipe and a 200ml eggplant-shaped flask, and the temperature was again heated to 200°C under normal pressure for 10 hours, and kept at 200°C for 7 hours. Then, a decompression device was attached to the round-bottomed flask, and the temperature was kept at 180 to 200° C. for 2 hours under a reduced pressure of 33 kPa. The water generated during the reaction was recovered into a 200 ml eggplant-shaped flask during the period of heating up from normal pressure to maintaining temperature under reduced pressure. Then, after the pressure was reduced to 3 kPa, the temperature was raised to 230° C. for 7.5 hours to perform polycondensation. As a result, 658 g of a yellowish-brown solid having 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 as a dihydric alcohol were placed. , 79 g (0.6 mol) of 4-benzenedimethanol, 87 g (1.1 mol) of 1,2-propanediol, 170 g (1.4 mol) of succinic acid as aliphatic dicarboxylic acid, and tetra-n-butyl titanic acid as catalyst After 0.06 g of 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 divided into the water produced by the reaction and others, the water is recovered, and the other low boilers are returned to the flask. After cooling until the gas stopped flowing out, the rectification device was dismantled, the round-bottomed flask was installed with a pipe, a cooling pipe and a 200ml eggplant-shaped flask, and the temperature was again heated to 230° C. under normal pressure for 2 hours, and kept at 230° C. for 30 minutes. After that, a decompression device was attached to the round-bottomed flask, and it was kept at 160 to 180° C. for 2 hours under a reduced pressure of 13.3 kPa. The water generated during the reaction was recovered into a 200 ml eggplant-shaped flask during the period of heating up from normal pressure to maintaining temperature under reduced pressure. Then, the pressure was reduced to 0.4 kPa, and the temperature was raised to 180° C. for 6.5 hours to perform polycondensation. As a result, 299 g of a yellow-brown transparent high-viscosity liquid having the following formula as the 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 1,4-benzenedimethanol residue and 1,2-propanediol residue is 4: 6.

[Chemical formula 4]

Example 3 Synthesis of Ester Compound H In a 1L glass four-necked round-bottom flask equipped with a stirrer, a thermometer and a rectifying device, 242 g (1.8 mol) of 2-phenoxyethanol as an aromatic monohydric alcohol and 242 g (1.8 mol) of 2-phenoxyethanol as a distillate were placed. After 249 g (4.0 mol) of ethylene glycol as a polyhydric alcohol, 322 g (2.7 mol) of succinic acid as aliphatic dicarboxylic acid, and 0.11 g of tetra-n-butyl titanate as a catalyst, 5 The temperature was raised to 225°C in 1 hour. The gas flowing out during the temperature rise is condensed by the rectification device, and divided into water and other low-boiling substances produced by the reaction, the water is recovered, and the other low-boiling substances are returned to the flask. After cooling until the gas stopped flowing out, the rectification device was dismantled, the round-bottomed flask was installed with a scalloped pipe, a cooling pipe and a 200 ml eggplant-shaped flask, and the temperature was again heated to 240° C. under normal pressure for 3 hours. The water produced during the reaction was recovered into a 200ml eggplant-shaped flask. After that, a decompression device was attached to 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 pale 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-L glass four-necked round-bottom flask equipped with a stirrer, a thermometer and a rectifying device, 391 g (2.8 mol) of 2-phenoxyethanol as an aromatic monohydric alcohol and 2-phenoxyethanol as a distillate were placed. After 302 g (3.4 mol) of 2-methyl-1,3-propanediol as a polyhydric alcohol, 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 , the temperature was raised to 240°C in 3 hours under normal pressure. The gas flowing out during the temperature rise is condensed by the rectification device, and divided into water and other low-boiling substances produced by the reaction, the water is recovered, and the other low-boiling substances are returned to the flask. After cooling until the gas stopped flowing out, the rectification device was dismantled, the round-bottomed flask was installed with a pipe, a cooling pipe and a 200 ml eggplant-shaped flask, and the temperature was again heated to 250° C. under normal pressure for 3 hours. The water produced during the reaction was recovered into a 200ml eggplant-shaped flask. Then, a decompression device was attached to 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-L glass four-necked round-bottom flask equipped with a stirrer, a thermometer and a distillation apparatus, 262 g (1.9 mol) of 2-phenoxyethanol as an aromatic monohydric alcohol and 262 g (1.9 mol) of 2-phenoxyethanol as a distillate were placed. 247 g (3.3 mol) of 1,2-propanediol as a polyhydric alcohol, 299 g (2.5 mol) of succinic acid as aliphatic dicarboxylic acid, and 0.07 g of tetra-n-butyl titanate as a catalyst, and then under normal pressure The temperature was raised to 245°C over 5 hours. The gas flowing out during the temperature rise is condensed by the rectification device, and divided into water and other low-boiling substances produced by the reaction, the water is recovered, and the other low-boiling substances are returned to the flask. After cooling until the gas stopped flowing out, the rectification device was dismantled, and the round-bottomed flask was installed with a scalloped pipe, a cooling pipe, a 200ml eggplant-shaped flask and a decompression device. After decompressing to 2.3kPa, it took 4.5 hours to heat up to 180°C for polycondensation. . The water produced during the reaction was recovered into a 200ml eggplant-shaped 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 L glass four-necked round bottom flask equipped with a stirrer, a thermometer and a rectifying apparatus, 190 g (1.8 mol) of benzyl alcohol as an aromatic monohydric alcohol and 1 as a dihydric alcohol were placed , 211 g (1.5 mol) of 4-benzenedimethanol, 232 g (2.0 mol) of succinic acid as aliphatic dicarboxylic acid, and 0.07 g of tetra-n-butyl titanate as a catalyst, and spent 11 The temperature was raised to 210°C in 1 hour. The gas flowing out during the temperature rise is condensed by the rectification device, and divided into the water produced by the reaction and the other, the water is recovered, and the other is returned to the flask. Then, the rectifying device was dismantled, and the round-bottomed flask was fitted with a scavenger tube, a cooling tube, a 200 ml eggplant-shaped flask and a decompression device, and kept at 160-190° C. for 12 hours under a reduced pressure of 13.3 kPa. During the decompression period, the water produced by the reaction was recovered into a 200 ml eggplant-shaped flask. Thereafter, the pressure was reduced to 0.4 kPa, and the temperature was raised to 180° C. for 4.5 hours to perform polycondensation. As a result, 423 g of a yellowish-brown solid having the following formula as a main component was obtained. The number average molecular weight of the ester compound C was 1000, and the acid value was 0.29 mgKOH/g.

[Chemical formula 8]

Comparative Example 2 Synthesis of Ester Compound D In a 1-L glass four-necked round-bottom flask equipped with a stirrer, a thermometer and a rectifying apparatus, 590 g (6.6 mol) of 1,3-butanediol as a diol and 590 g (6.6 mol) of 1,3-butanediol as a diol were placed. After 292 g (2.0 mol) of adipic acid and 166 g (1.0 mol) of terephthalic acid as a carboxylic acid, and 0.11 g of tetra-n-butyl titanate as a catalyst, the temperature was raised to 230°C over 10 hours under normal pressure. . The gas flowing out during the temperature rise is condensed by the rectification device, and divided into the water produced by the reaction and the other, the water is recovered, and the other is returned to the flask. After cooling until the gas stopped flowing out, the rectification device was dismantled, the round-bottomed flask was installed with a pipe, a cooling pipe and a 200ml eggplant-shaped flask, and the temperature was again heated to 230° C. under normal pressure for 2 hours, and kept at 230° C. for 16 hours. The water produced during the reaction was recovered into a 200ml eggplant-shaped flask. Then, a decompression 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. for 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 at 120°C, and low boilers were 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 adipic acid residues to terephthalic acid residues was 2:1.

[Chemical formula 9]

Comparative Example 3 Synthesis of Ester Compound E 367 g (4.8 mol) of 1,2-propanediol as a dihydric alcohol and 367 g (4.8 mol) of 1,2-propanediol as a dihydric carboxylic acid were placed in a 1 L glass four-necked round-bottomed flask equipped with a stirrer, a thermometer and a distillation apparatus. After 461 g (3.2 mol) of adipic acid as an acid, and 0.13 g of tetra-n-butyl titanate as a catalyst, the temperature was raised to 180° C. over 7.5 hours under normal pressure. The gas flowing out during the temperature rise is condensed by the rectification device, and divided into the water produced by the reaction and the other, the water is recovered, and the other is returned to the flask. Then, the rectification device was dismantled, and the round-bottomed flask was fitted with a pipe, a cooling tube, a 200-ml eggplant-shaped flask, and a decompression device, and the temperature was raised to 180° C. for polycondensation while the pressure was reduced to 0.7 kPa for 15.5 hours. 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 at 120°C, and low boilers were recovered. As a result, 697 g of a pale 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-L glass four-necked round-bottom flask equipped with a stirrer, a thermometer, and a rectification apparatus, 365 g (4.8 mol) of 1,2-propanediol as a diol and 365 g (4.8 mol) of 1,2-propanediol as a dicarboxylic acid were placed. After 467 g (3.2 mol) of adipic acid as an 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 divided into the water produced by the reaction and the other, the water is recovered, and the other is returned to the flask. After cooling until the gas stopped flowing out, the rectification device was dismantled, and the round-bottomed flask was installed with a pipe, a cooling pipe and a 200 ml eggplant-shaped flask, and kept at 180° C. for 4 hours. Then, a decompression device was attached to the round-bottomed flask, and the temperature was kept 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 200ml eggplant-shaped flask. After that, the temperature was raised to 180°C while the pressure was reduced to 0.7 kPa over 11.5 hours 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-bottom flask equipped with a stirrer, a thermometer and a rectification apparatus, 301 g (4.0 mol) of 1,2-propanediol as a diol and 301 g (4.0 mol) of an aromatic mono 122 g (1.0 mol) of benzoic acid as a carboxylic acid, 8 g (0.05 mol) of adipic acid as a dicarboxylic acid, 24 g (0.2 mol) of phthalic anhydride, and 0.04 of tetra-n-butyl titanate as a catalyst After g, the temperature was raised to 200°C over 6.5 hours under normal pressure. The gas flowing out during the temperature rise is condensed by the rectification device, and divided into the water produced by the reaction and the other, the water is recovered, and the other is returned to the flask. Then, the rectification device was dismantled, and the round-bottomed flask was fitted with a pipe, a cooling tube, a 200 ml eggplant-shaped flask and a decompression device, and kept at 150-160° C. for 18 hours under a reduced pressure of 24.0 kPa. During the decompression period, the water produced by the reaction was recovered into a 200 ml eggplant-shaped flask. After that, the pressure was reduced to 0.7 kPa over 8 hours, and the temperature was raised 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 adipic acid residues to phthalic acid residues 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-propanediol as diols, succinic acid and terephthalic acid as dicarboxylic acids and acetic anhydride to obtain a pale yellow transparent liquid with the following formula as the 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, and the molar of ethylene glycol residues and 1,2-propanediol residues The ratio is 1:1 and the molar ratio of succinic acid residues to terephthalic acid residues is 1:1.

[Chemical formula 13]

<Formation and evaluation of film> Example 11 A solution obtained 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. 5g was placed in a petri dish with a diameter of 94 mm, and after covering the lid, the solution was cast over the entire petri dish. Then, it was left to stand horizontally at room temperature overnight, and then dried at 50° C. for 0.5 hour and then at 100° C. for 1 hour to obtain a thin film having a thickness of 25 μm. The results of measuring the moisture permeability and transparency of the obtained films by the aforementioned methods are shown in Table 1.

Example 12 Except having used the ester compound B instead of the ester compound A, the same operation as Example 1 was performed, and the thin film of thickness 27 micrometers was obtained. The results of measuring the moisture permeability and transparency of the obtained films by the aforementioned methods are shown in Table 1.

Example 13 The same operation as in Example 1 was carried out except that the ester compound H was used instead of the ester compound A, to obtain a film having a thickness of 26 μm. The results of measuring the moisture permeability and transparency of the obtained films by the aforementioned methods are shown in Table 1.

Example 14 Except having used the ester compound I instead of the ester compound A, the same operation as Example 1 was performed, and the thin film of thickness 28 micrometers was obtained. The results of measuring the moisture permeability and transparency of the obtained films by the aforementioned methods are shown in Table 1.

Example 15 Except having used the ester compound J instead of the ester compound A, the same operation as Example 1 was performed, and the thin film of thickness 25 micrometers was obtained. The results of measuring the moisture permeability and transparency of the obtained films by the aforementioned methods are shown in Table 1.

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 thin film having a thickness of 28 μm. The results of measuring the moisture permeability and transparency of the obtained films by the aforementioned methods are shown in Table 1.

Comparative Example 12 The same operation as in Example 1 was performed except that the ester compound D was used instead of the ester compound A, to obtain a thin film having a thickness of 26 μm. The results of measuring the moisture permeability and transparency of the obtained films by the aforementioned methods are shown in Table 1.

Comparative Example 13 Except having used the ester compound E instead of the ester compound A, the same operation as in Example 1 was performed to obtain a film with a thickness of 26 μm. The results of measuring the moisture permeability and transparency of the obtained films by the aforementioned methods are shown in Table 1.

Comparative Example 14 The same operation as in Example 1 was performed except that the ester compound F was used instead of the ester compound A, to obtain a thin film having a thickness of 25 μm. The results of measuring the moisture permeability and transparency of the obtained films by the aforementioned methods are shown in Table 1.

Comparative Example 15 The same operation as in Example 1 was performed except that the ester compound G was used instead of the ester compound A, to obtain a thin film having a thickness of 28 μm. The results of measuring the moisture permeability and transparency of the obtained films by the aforementioned methods are shown in Table 1.

Comparative Example 16 Except having used the phosphate ester plasticizer 1 in place of the ester compound A, the same operation as in Example 1 was performed to obtain a film having a thickness of 25 μm. The results of measuring the moisture permeability and transparency of the obtained films by the aforementioned methods are shown in Table 1.

Comparative example 17 Except having used the phosphate ester plasticizer 2 instead of the ester compound A, the same operation as Example 1 was performed, and the film of thickness 24 micrometers was obtained. The results of measuring the moisture permeability and transparency of the obtained films by the aforementioned methods are shown in Table 1.

Comparative Example 18 Except not using the ester compound A, the same operation as in Example 1 was performed to obtain a film with a thickness of 24 μm. The results of measuring the moisture permeability and transparency of the obtained films by the aforementioned methods are shown in Table 1.

Comparative Example 19 The same operation as in Example 1 was performed except that the ester compound K was used instead of the ester compound A, to obtain a thin film having a thickness of 26 μm. The results of measuring the moisture permeability and transparency of the obtained films by the aforementioned methods are shown in Table 1.

*EG：乙二醇、1,2-PG：1,2-丙二醇 BDM：1,4-苯二甲醇、1,3-BG：1,3-丁二醇[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, as in Examples 11 to 15 and Comparative Example 11, the films containing the ester compound capped with aromatic monohydric alcohol, like Comparative Examples 12, 13 and 19, the ester compound capped with acetic anhydride, and Comparative Example 14 were not processed. Compared with the capped ester compound, the ester compound capped with benzoic acid in Comparative Example 15, or the films of Comparative Examples 16 and 17 generally containing the previously used phosphate-based plasticizer, the moisture permeability is obviously lower, Moisture permeability resistance is improved. Moreover, it turns out that the film of the comparative example 11 containing the ester compound which the dihydric alcohol is only an aromatic diol and an aromatic monohydric alcohol terminus is inferior to transparency (haze value) although the moisture permeability is low. As described above, it was 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 permeation resistance can be improved.

Claims (9)

A modifier for cellulose ester resin, comprising an ester compound represented by the following formula (1):

[In formula (1), A ¹ and A ² represent the same or different at least one aliphatic dicarboxylic acid residue selected from the group consisting of oxalic acid, malonic acid and succinic acid; 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; the aforementioned aliphatic diol residue is at least one diol residue selected from the group consisting of ethylene glycol, 1,2-propanediol and 2-methyl-1,3-propanediol; the aforementioned aromatic diol residues are selected at least 1 selected from the group consisting of hydrogen roll, resorcinol, 1,2-benzenedimethanol, 1,4-benzenedimethanol, 1,2-benzenediethanol, and 1,4-benzenediethanol A dihydric alcohol residue; M ¹ and M ² represent the same or different ones selected from the group consisting of phenol, 2-cresol, 3-cresol, 4-cresol, benzyl alcohol, 2-methylbenzyl alcohol, 3-methyl benzyl alcohol At least one aromatic monohydric alcohol residue from the group consisting of benzyl alcohol, 4-methylbenzyl alcohol, 1-phenethyl alcohol, 2-phenethyl alcohol, 2-benzyloxyethyl alcohol and 2-phenoxyethyl alcohol; n is 1 or more integer]. The modifier for cellulose ester resin according to claim 1, wherein the number-average molecular weight of the aforementioned ester compound is 500-2500. The modifier for cellulose ester resin according to claim 1 or 2, wherein M ¹ and M ² are at least one aromatic selected from the group consisting of 2-benzyloxyethanol and 2-phenoxyethanol Residues of monohydric alcohols. The modifier for cellulose ester resin according to claim 1 or 2, wherein the aforementioned G ¹ is the aforementioned aliphatic diol residue. The modifier for cellulose ester resin according to claim 1 or 2, wherein the aforementioned G ¹ is a combination of the aforementioned aliphatic diol residues and aromatic diol residues, and the aforementioned diol residues in the aforementioned ester compound Among them, the molar ratio of the above-mentioned aromatic diol residues is 80% or less. The modifier for cellulose ester resin according to claim 1 or 2, wherein the hydroxyl value of the aforementioned ester compound is 30 mgKOH/g or less. The modifier for cellulose ester resin according to claim 1 or 2, wherein the acid value of the aforementioned ester compound is 3 mgKOH/g or less. A cellulose ester resin composition comprising the modifier for cellulose ester resin according to any one of claims 1 to 7, and a cellulose ester resin. An optical film comprising the cellulose ester resin composition of claim 8.