Modifier for cellulose ester resin, cellulose ester resin composition, molded article, optical film, and display device

Abstract

To provide a modifier for cellulose ester resins that can suppress blooming out of the modifier on the surface of cellulose ester resin composition molded article and contamination of manufacturing equipment.SOLUTION: There is provided a modifier for cellulose ester resins containing polyol ester compounds comprising reaction components of 3- to 6-valent aliphatic polyols, aromatic monocarboxylic acids, and aliphatic monocarboxylic acids, wherein the molar ratio of aromatic monocarboxylic acids to aliphatic monocarboxylic acids satisfies aromatic monocarboxylic acids:aliphatic monocarboxylic acids=95:5 to 60:40.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a modifier for cellulose ester resin, a cellulose ester resin composition, an optical film, and a display device. [Background technology]

[0002] Cellulose ester resins are used in a wide variety of applications, such as sheets, films, electric wire coatings, toys, medical devices, and food packaging materials. Among these, cellulose ester resin films have excellent transparency, optical properties, toughness, and other characteristics, and are therefore widely used as polarizing film protective films and retardation films for image display devices.

[0003] The films used in the above-mentioned image display devices are given mechanical properties such as moisture permeability and moist heat resistance, and optical properties such as transparency, depending on the purpose, and modifiers have been proposed to give these functions to the films (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-191219 Summary of the Invention [Problem to be solved by the invention]

[0005] The benzoate triester modifier disclosed in Patent Document 1 can impart excellent moisture permeability to a molded article of a cellulose ester resin composition, but since the benzoate triester modifier is prone to solidification, there is a risk of the benzoate triester modifier blooming out onto the surface of the molded article of the cellulose ester resin composition. Furthermore, during the heating step in the molded article production process, there is a risk of the benzoate triester modifier scattering from the cellulose ester resin composition and adhering to and solidifying on the surface of the molded article or the production equipment, causing contamination.

[0006] The problem to be solved by the present invention is to provide a modifier for cellulose ester resins which can suppress bloom-out of the modifier on the surface of a molded article of a cellulose ester resin composition and contamination of production equipment. Another problem to be solved by the present invention is to provide a molded article and an optical film that are free from bloom-out of the modifier. [Means for solving the problem]

[0007] As a result of intensive research to solve the above problems, the present inventors have discovered that for a cellulose ester resin modifier, which is a polyol ester compound having a tri- to hexavalent aliphatic polyol and an aromatic monocarboxylic acid as reactive components, by also using a specific amount of aliphatic monocarboxylic acid as a reactive component, the modifier can be made less likely to solidify without impairing the performance of the modifier, and have completed the present invention.

[0008] That is, the present invention relates to the following modifiers for cellulose ester resins, etc. A modifier for cellulose ester resins, comprising a polyol ester compound having a 1.3 to 6-valent aliphatic polyol, an aromatic monocarboxylic acid, and an aliphatic monocarboxylic acid as reaction components, The modifier for cellulose ester resins satisfies the molar ratio of the aromatic monocarboxylic acid to the aliphatic monocarboxylic acid of aromatic monocarboxylic acid:aliphatic monocarboxylic acid=95:5 to 60:40. 2. The modifier for cellulose ester resins according to 1, wherein the aliphatic polyol is a tri- to hexa-valent aliphatic polyol having 2 to 12 carbon atoms. 3. The cellulose ester resin modifier according to 1 or 2, wherein the aliphatic polyol is one or more selected from the group consisting of trimethylolpropane, sorbitol, 1,4-sorbitan, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, 2-methyl-1,2,3-propanetriol, 2-methyl-1,2,4-butanetriol, and glycerin. 4. The modifier for cellulose ester resins according to any one of 1 to 3, wherein the aromatic monocarboxylic acid is an aromatic monocarboxylic acid having 6 to 12 carbon atoms. 5. The modifier for cellulose ester resins according to any one of 1 to 4, wherein the aliphatic monocarboxylic acid is an aliphatic monocarboxylic acid having 4 to 10 carbon atoms. 6. The modifier for cellulose ester resin according to any one of 1 to 5, further comprising a diester compound having an aliphatic diol and an aromatic monocarboxylic acid as reaction components. 7. The modifier for cellulose ester resins according to 6, wherein the aliphatic diol is an aliphatic diol having 2 to 6 carbon atoms. 8. The cellulose ester resin modifier according to 6 or 7, wherein the aliphatic diol is one or more selected from ethylene glycol, neopentyl glycol, propylene glycol, hexanediol, polyethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, 1,4-cyclohexanedimethanol, D-isosorbide, L-isosorbide, isomannide, erythritan, and 1,4-dihydroxy-2-butene. 9. The modifier for cellulose ester resins according to any one of 6 to 8, wherein the aromatic monocarboxylic acid is an aromatic monocarboxylic acid having 6 to 12 carbon atoms. 10. The modifier for cellulose ester resins according to any one of 6 to 9, wherein the mass ratio of the polyol ester compound to the diester compound satisfies polyol ester compound:diester compound=99:1 to 40:60. 11. The modifier for cellulose ester resin according to any one of 1 to 10, which contains a polyester polyol represented by the following general formula (1): [ka] (In the general formula (1), G 1 is an aliphatic diol residue having 2 to 12 carbon atoms or an aromatic diol residue having 6 to 18 carbon atoms, A 1 is an aliphatic dicarboxylic acid residue having 2 to 12 carbon atoms or an aromatic dicarboxylic acid residue having 6 to 14 carbon atoms, n represents the number of repetitions. However, for each repetition, G 1 may be the same or different, and A 1 may be the same or different.) 12. The modifier for cellulose ester resin according to 11, wherein the mass ratio of the polyol ester compound to the polyester polyol represented by general formula (1) satisfies polyol ester compound:polyester polyol represented by general formula (1) = 99:1 to 25:75. 13. The modifier for cellulose ester resin according to any one of 1 to 12, which contains a polyester represented by the following general formula (2): [ka] (In the general formula (2), G 2 is an aliphatic diol residue having 2 to 12 carbon atoms or an aromatic diol residue having 6 to 18 carbon atoms, A 2 is an aliphatic dicarboxylic acid residue having 2 to 12 carbon atoms or an aromatic dicarboxylic acid residue having 6 to 14 carbon atoms, B 1 and B 2 are each independently an aliphatic monocarboxylic acid residue having 1 to 8 carbon atoms or an aromatic monocarboxylic acid residue having 6 to 12 carbon atoms, m represents the number of repetitions. However, for each repetition, G 2 may be the same or different, and A 2 may be the same or different.) 14. The modifier for cellulose ester resin according to 13, wherein the mass ratio of the polyol ester compound to the polyester represented by general formula (2) satisfies polyol ester compound:polyester represented by general formula (2)=99:1 to 25:75. 15. A cellulose ester resin composition comprising a cellulose ester resin and the modifier for cellulose ester resin according to any one of 1 to 14. 16. The cellulose ester resin composition according to 15, wherein the modifier for cellulose ester resin is contained in an amount of 1 to 30 parts by mass relative to 100 parts by mass of the cellulose ester resin. 17. A molded article of the cellulose ester resin composition according to 15 or 16. 18. An optical film obtained by using the cellulose ester resin composition according to 15 or 16. A display device comprising the optical film according to 19.18. [Effects of the Invention]

[0009] According to the present invention, there is provided a modifier for cellulose ester resins which can suppress bloom-out of the modifier on the surface of a molded article of a cellulose ester resin composition and contamination of production equipment. The present invention can provide a molded article and an optical film that are free from bloom-out of the modifier. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the present invention will be described below. The present invention is not limited to the following embodiment, and can be implemented by making appropriate modifications within the scope that does not impair the effects of the present invention. The compounds in this specification may be derived from fossil resources or biological resources.

[0011] [Modifier for cellulose ester resin] (Polyol ester compound) The cellulose ester resin modifier of the present invention contains a polyol ester compound having a tri- to hexavalent aliphatic polyol, an aromatic monocarboxylic acid, and an aliphatic monocarboxylic acid as reaction components, and the molar ratio of the aromatic monocarboxylic acid to the aliphatic monocarboxylic acid in the reaction components of the polyol ester compound satisfies the aromatic monocarboxylic acid:aliphatic monocarboxylic acid=95:5 to 60:40. The term "reaction components" as used herein refers to components that constitute the polyol ester compound, and does not include solvents, catalysts, etc. that do not constitute the polyol ester compound.

[0012] Polyol ester compounds having only an aliphatic polyol and an aromatic monocarboxylic acid as reaction components tend to solidify, and there is a risk that the polyol ester compounds may bloom out and / or bloom out when made into a cellulose ester resin composition described below. The polyol ester compound contained in the cellulose ester resin modifier of the present invention (hereinafter sometimes simply referred to as "the polyol ester compound of the present invention") can solve the problem of solidification without impairing the modifying effect by using a specific amount of aliphatic monocarboxylic acid in addition to aromatic monocarboxylic acid. In addition, although polyester-based modifiers also exist as cellulose ester resin modifiers, polyol ester compounds generally have lower viscosity than polyester-based modifiers, and the cellulose ester resin modifier of the present invention also has the advantage of being easy to handle.

[0013] The tri- to hexavalent aliphatic polyol, which is a reaction component of the polyol ester compound, is preferably a tri- to hexavalent aliphatic polyol having 2 to 12 carbon atoms, and more preferably one or more selected from trimethylolpropane, sorbitol, 1,4-sorbitan, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, 2-methyl-1,2,3-propanetriol, 2-methyl-1,2,4-butanetriol, and glycerin.

[0014] The aromatic monocarboxylic acid that is a reaction component of the polyol ester compound is preferably an aromatic monocarboxylic acid having 6 to 12 carbon atoms, and more preferably one or more selected from benzoic acid, dimethylbenzoic acid, trimethylbenzoic acid, tetramethylbenzoic acid, ethylbenzoic acid, propylbenzoic acid, butylbenzoic acid, cumic acid, para-tert-butylbenzoic acid, orthotoluic acid, meta-toluic acid, para-toluic acid, ethoxybenzoic acid, propoxybenzoic acid, naphthoic acid, and anisic acid.

[0015] The aliphatic monocarboxylic acid, which is a reaction component of the polyol ester compound, is preferably an aliphatic monocarboxylic acid having 4 to 10 carbon atoms, and more preferably one or more selected from butyric acid (butanoic acid), valeric acid, caproic acid, heptanoic acid, caprylic acid, 2-ethylhexanoic acid, nonanoic acid, and capric acid.

[0016] The reaction components of the polyol ester compound may contain other reaction components in addition to the tri- to hexavalent aliphatic polyol, aromatic monocarboxylic acid, and aliphatic monocarboxylic acid, as long as the effects of the present invention are not impaired. The content of the other reaction components may be, for example, 5% by mass or less, 3% by mass or less, or 1% by mass or less of the total amount of the reaction components of the polyol ester compound.

[0017] The method for producing the polyol ester compound is not particularly limited, and the compound can be produced by a known method.

[0018] The polyol ester compound contained in the cellulose ester resin modifier of the present invention may be one type alone, or two or more types of polyol ester compounds having different structures may be used in combination.

[0019] (diester compounds) The modifier for cellulose ester resin of the present invention preferably further contains a diester compound having an aliphatic diol and an aromatic monocarboxylic acid as reaction components. The modifier of the present invention contains a diester compound, which can improve the moisture permeability of a cellulose ester resin molded article containing the modifier. Furthermore, the modifier of the present invention contains a diester compound, which can reduce the viscosity of the modifier itself and improve the handleability of the modifier.

[0020] The aliphatic diol that is a reaction component of the diester compound is preferably an aliphatic diol having 2 to 6 carbon atoms, and more preferably one or more selected from ethylene glycol, neopentyl glycol, propylene glycol (1,2-propanediol), hexanediol, polyethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, 1,4-cyclohexanedimethanol, D-isosorbide, L-isosorbide, isomannide, erythritan, and 1,4-dihydroxy-2-butene.

[0021] The aromatic monocarboxylic acid which is a reaction component of the diester compound is preferably an aromatic monocarboxylic acid having 6 to 12 carbon atoms, and more preferably one or more selected from benzoic acid, dimethylbenzoic acid, trimethylbenzoic acid, tetramethylbenzoic acid, ethylbenzoic acid, propylbenzoic acid, butylbenzoic acid, cumic acid, para-tert-butylbenzoic acid, orthotoluic acid, meta-toluic acid, para-toluic acid, ethoxybenzoic acid, propoxybenzoic acid, naphthoic acid, and anisic acid.

[0022] The reaction components of the diester compound may contain other reaction components in addition to the aliphatic diol and aromatic monocarboxylic acid, provided that the effects of the present invention are not impaired. The content of the other reaction components may be, for example, 5% by mass or less, 3% by mass or less, or 1% by mass or less of the total amount of the reaction components of the diester compound.

[0023] The method for producing the diester compound is not particularly limited, and the compound can be produced by a known method.

[0024] The diester compound contained in the cellulose ester resin modifier of the present invention may be one type alone, or two or more types of diester compounds having different structures may be used in combination.

[0025] When the cellulose ester resin modifier of the present invention contains both a polyol ester compound and a diester compound, the mass ratio of the polyol ester compound to the diester preferably satisfies the polyol ester compound:diester compound=99:1 to 40:60, and more preferably satisfies the polyol ester compound:diester compound=90:10 to 60:40.

[0026] (Polyester polyol (1)) The modifier for cellulose ester resin of the present invention preferably contains a polyester polyol represented by the following general formula (1): Hereinafter, the polyester polyol represented by general formula (1) may be referred to as "polyester polyol (1)".

[0027] [ka] (In the general formula (1), G 1 is an aliphatic diol residue having 2 to 12 carbon atoms or an aromatic diol residue having 6 to 18 carbon atoms, A 1 is an aliphatic dicarboxylic acid residue having 2 to 12 carbon atoms or an aromatic dicarboxylic acid residue having 6 to 14 carbon atoms, n represents the number of repetitions. However, for each repetition, G 1 may be the same or different, and A 1 may be the same or different.)

[0028] In the present invention, the term "carboxylic acid residue" refers to the organic group remaining after removing the hydroxyl group from a carboxylic acid. In the present invention, the term "alcohol residue" refers to the organic group remaining after removing a hydrogen atom from an alcohol. In the present invention, the term "diol residue" refers to the organic group remaining after removing hydrogen atoms from a diol. In the present invention, the term "glycol residue" refers to the organic group remaining after removing a hydrogen atom from glycol.

[0029] G 1 The aliphatic chain of the aliphatic diol residue having 2 to 12 carbon atoms may be linear or branched, and may contain an alicyclic structure and / or an ether bond. 1 The aliphatic chain of the aliphatic diol residue may be a saturated aliphatic chain or an unsaturated aliphatic chain having a carbon-carbon unsaturated bond.

[0030] G 1 is preferably an alkylene glycol residue having 2 to 12 carbon atoms or an oxyalkylene glycol residue having 2 to 12 carbon atoms.

[0031] G 1 Examples of the alkylene glycol residue having 2 to 12 carbon atoms include an ethylene glycol residue, a 1,2-propylene glycol residue, a 1,3-propanediol residue, a 1,2-butanediol residue, a 1,3-butanediol residue, a 2-methyl-1,3-propanediol residue, a 1,4-butanediol residue, a 1,5-pentanediol residue, a 2,2-dimethyl-1,3-propanediol (neopentyl glycol) residue, a 2,2-diethyl-1,3-propanediol (3,3-dimethylpentyl pentanediol) residue, a 2,2-dimethyl-1,3-propanediol (neopentyl glycol) residue, a 2,2-dimethyl ...neopentyl glycol) residue, a 2,2-dimethyl-1,3-propanediol (neopentyl glycol) residue, a 2,2-dimethyl-1,3-propanediol (neopentyl glycol) residue, a 2,2-dimethyl-1,3-propanediol (neopentyl glycol) residue, a 2,2-dimethyl-1,3-propanediol (neopentyl glycol) residue, a 2,2-dimethyl-1,3-propanediol (neopentyl glycol) pentane) residue, 2-n-butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane) residue, 3-methyl-1,5-pentanediol residue, 1,6-hexanediol residue, 2,2,4-trimethyl-1,3-pentanediol residue, 2-ethyl-1,3-hexanediol residue, 2-methyl-1,8-octanediol residue, 1,9-nonanediol residue, 1,10-decanediol residue, 1,12-dodecanediol residue, 1,2-dodecanediol residue, and the like.

[0032] G 1The alkylene glycol residue having 2 to 12 carbon atoms may contain an alicyclic structure, and examples of the aliphatic diol residue having 2 to 12 carbon atoms containing the alicyclic structure include a 1,3-cyclopentanediol residue, a 1,2-cyclohexanediol residue, a 1,3-cyclohexanediol residue, a 1,4-cyclohexanediol residue, a 1,2-cyclohexanedimethanol residue, and a 1,4-cyclohexanedimethanol residue.

[0033] G 1 The oxyalkylene glycol residue having 2 to 12 carbon atoms is an alkylene glycol residue containing one or more ether bonds (—O—), and examples of the oxyalkylene glycol residue having 2 to 12 carbon atoms include a diethylene glycol residue, a triethylene glycol residue, a tetraethylene glycol residue, a dipropylene glycol residue, and a tripropylene glycol residue.

[0034] G 1 Examples of the aromatic diol residue having 6 to 18 carbon atoms include residues of hydroquinone, resorcinol, bisphenol A, alkylene oxide adducts of bisphenol A, etc.; bisphenol F, alkylene oxide adducts of bisphenol F, etc.; biphenol, alkylene oxide adducts of biphenol, etc.

[0035] A 1 Examples of the aliphatic dicarboxylic acid residue having 2 to 12 carbon atoms include residues of oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, sebacic acid, decanedioic acid, maleic acid, fumaric acid, 1,2-dicarboxycyclohexane, 1,4-dicarboxycyclohexane, and 1,2-dicarboxycyclohexene.

[0036] A 1Examples of the aromatic dicarboxylic acid residue having 6 to 14 carbon atoms include residues of phthalic acid, isophthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and 1,8-naphthalenedicarboxylic acid.

[0037] A 1 The aromatic dicarboxylic acid residue having 6 to 14 carbon atoms is preferably an aromatic dicarboxylic acid residue having 6 to 13 carbon atoms, more preferably an aromatic dicarboxylic acid residue having 6 to 12 carbon atoms, and even more preferably an aromatic dicarboxylic acid residue having 8 to 12 carbon atoms. Also, A 1 The aromatic dicarboxylic acid residue having 6 to 14 carbon atoms may further be substituted with a substituent (for example, an alkyl group having 1 to 6 carbon atoms), and an example thereof is a residue of dimethyl terephthalic acid.

[0038] A 1 preferably contains an aromatic dicarboxylic acid residue having 6 to 14 carbon atoms, and more preferably contains an aromatic dicarboxylic acid residue having 6 to 13 carbon atoms.

[0039] The number of repetitions of n is an integer ranging from 0 to 20, for example. The average value of the number of repetitions, n, is preferably in the range of 0.5 to 10.0, more preferably in the range of 0.6 to 8.0, and even more preferably in the range of 0.8 to 7.0. The average value of the repeating number of n can be calculated from the number average molecular weight of the polyester of the present invention.

[0040] The number average molecular weight (Mn) of the polyester polyol (1) is, for example, in the range of 100 to 5,000, preferably in the range of 300 to 2,000, and more preferably in the range of 350 to 1,500. The number average molecular weight (Mn) is a value calculated as polystyrene based on gel permeation chromatography (GPC) measurement, and is measured by the method described in the Examples.

[0041] The acid value of the polyester polyol (1) is, for example, 10 mgKOH / g or less, preferably 5 mgKOH / g or less, more preferably 3 mgKOH / g or less, and even more preferably 1 mgKOH / g or less. The lower limit of the acid value of the polyester polyol (1) is not particularly limited, but is, for example, 0 mgKOH / g. The acid value of the polyester is confirmed by the method described in the examples.

[0042] The properties of the polyester polyol (1) vary depending on the number average molecular weight, composition, etc., but are usually liquid, solid, paste, etc. at room temperature.

[0043] The polyester polyol (1) can be obtained, for example, by using a diol and a dicarboxylic acid constituting each residue as reaction raw materials, and the amount of hydroxyl groups derived from the diol may be set in excess of the amount of carboxyl groups derived from the dicarboxylic acid. Here, the reaction raw materials mean raw materials constituting a polyester, and do not include solvents or catalysts that do not constitute a polyester. The specific method for producing the polyester polyol (1) is not particularly limited, and it can be produced by a known method.

[0044] The modifier for cellulose ester resin of the present invention may contain, for example, two or more polyester polyols (1) having different structures.

[0045] When the cellulose ester resin modifier of the present invention contains polyester polyol (1), the mass ratio of the polyol ester compound to the polyester polyol (1) preferably satisfies the range of polyol ester compound:polyester polyol (1)=99:1 to 25:75, more preferably 90:10 to 30:70, and even more preferably 90:10 to 40:60.

[0046] (Polyester (2)) The modifier for cellulose ester resin of the present invention preferably contains a polyester represented by the following general formula (2): Hereinafter, the polyester represented by general formula (2) may be referred to as "polyester (2)".

[0047] [ka] (In the general formula (2), G 2 is an aliphatic diol residue having 2 to 12 carbon atoms or an aromatic diol residue having 6 to 18 carbon atoms, A 2 is an aliphatic dicarboxylic acid residue having 2 to 12 carbon atoms or an aromatic dicarboxylic acid residue having 6 to 14 carbon atoms, B 1 and B 2 are each independently an aliphatic monocarboxylic acid residue having 1 to 8 carbon atoms or an aromatic monocarboxylic acid residue having 6 to 12 carbon atoms, m represents the number of repetitions. However, for each repetition, G 2 may be the same or different, and A 2 may be the same or different.)

[0048] G 2 The aliphatic diol residue having 2 to 12 carbon atoms is G 1 is the same as the aliphatic diol residue having 2 to 12 carbon atoms. G 2 The aromatic diol residue having 6 to 18 carbon atoms is G 1 is the same as the aromatic diol residue having 6 to 18 carbon atoms. A 2 The aliphatic dicarboxylic acid residue having 2 to 12 carbon atoms is A 1 is the same as the aliphatic dicarboxylic acid residue having 2 to 12 carbon atoms. A 2 The aromatic dicarboxylic acid residue having 6 to 14 carbon atoms is A 1 is the same as the aromatic dicarboxylic acid residue having 6 to 14 carbon atoms.

[0049] B 1 and B 2 Examples of the aliphatic monocarboxylic acid residue having 1 to 8 carbon atoms include residues of acetic acid, propionic acid, butanoic acid, hexanoic acid, and cyclohexanecarboxylic acid.

[0050] B 1 and B 2 Examples of the aromatic monocarboxylic acid residue having 6 to 12 carbon atoms include residues of benzoic acid, dimethylbenzoic acid, trimethylbenzoic acid, tetramethylbenzoic acid, ethylbenzoic acid, propylbenzoic acid, butylbenzoic acid, cumic acid, para-tert-butylbenzoic acid, orthotoluic acid, meta-toluic acid, para-toluic acid, ethoxybenzoic acid, propoxybenzoic acid, naphthoic acid, and anisic acid. B 1 and B 2 The aromatic monocarboxylic acid residue having 6 to 12 carbon atoms is preferably an aromatic monocarboxylic acid residue having 6 to 11 carbon atoms.

[0051] The number of repetitions of m is an integer in the range of 0 to 20, for example. The average value of the number of repetitions of m is preferably in the range of 0.5 to 10.0, more preferably in the range of 0.6 to 8.0, and even more preferably in the range of 0.8 to 7.0. The average value of the repeating number of m can be calculated from the number average molecular weight of the polyester of the present invention.

[0052] The number average molecular weight (Mn) of the polyester (2) is, for example, in the range of 100 to 5,000, preferably in the range of 300 to 2,000, and more preferably in the range of 350 to 1,500. The number average molecular weight (Mn) is a value calculated as polystyrene based on gel permeation chromatography (GPC) measurement, and is measured by the method described in the Examples.

[0053] The acid value of the polyester (2) is, for example, 10 mgKOH / g or less, preferably 5 mgKOH / g or less, more preferably 3 mgKOH / g or less, and even more preferably 1 mgKOH / g or less. The lower limit of the acid value of the polyester (2) is not particularly limited, but is, for example, 0 mgKOH / g. The acid value of the polyester is confirmed by the method described in the examples.

[0054] The properties of the polyester (2) vary depending on the number average molecular weight, composition, etc., but are usually liquid, solid, paste, etc. at room temperature.

[0055] The polyester (2) can be obtained, for example, by using a diol, a dicarboxylic acid, and a monocarboxylic acid constituting each residue as reaction raw materials, such as by reacting the polyester polyol (1) with a monocarboxylic acid. Here, the reaction raw materials refer to raw materials that constitute a polyester, and do not include solvents or catalysts that do not constitute a polyester. The specific method for producing the polyester (2) is not particularly limited, and it can be produced by a known method.

[0056] The modifier for cellulose ester resin of the present invention may contain, for example, two or more types of polyesters (2) having different structures.

[0057] When the cellulose ester resin modifier of the present invention contains polyester (2), the mass ratio of the polyol ester compound to the polyester (2) preferably satisfies the range of polyol ester compound:polyester (2)=99:1 to 25:75, more preferably 90:10 to 30:70, and even more preferably 90:10 to 40:60.

[0058] The cellulose ester resin modifier of the present invention is preferably composed of the polyol ester compound of the present invention and the diester compound of the present invention (excluding polyester polyol (1) and polyester (2)); composed of the polyol ester compound of the present invention and polyester polyol (1) (excluding the diester compound of the present invention and polyester (2)); or composed of the polyol ester compound of the present invention and polyester (2) (excluding the diester compound of the present invention and polyester polyol (1)).

[0059] [Cellulose ester resin composition] The cellulose ester resin composition of the present invention contains a cellulose ester resin and the modifier for cellulose ester resin of the present invention.

[0060] The content of the modifier for cellulose ester resin of the present invention in the cellulose ester resin composition is, for example, in the range of 0.1 to 50 parts by mass, preferably in the range of 1 to 30 parts by mass, and more preferably in the range of 3 to 20 parts by mass, relative to 100 parts by mass of the cellulose ester resin.

[0061] (cellulose ester resin) Examples of cellulose ester resins include cellulose acetate (CA), cellulose diacetate (DAC), cellulose triacetate (TAC), cellulose acetate propionate (CAP), cellulose acetate butyrate (CAB), cellulose acetate phthalate, polycaprolactone-grafted cellulose acetate, etc. Among these, acetylated celluloses such as cellulose acetate, cellulose diacetate, and cellulose triacetate are preferred because of their good mechanical properties (tensile strength, bending strength, bending elasticity, etc.). The cellulose ester resins can be used alone or in combination of two or more.

[0062] When the cellulose ester resin is acetylated cellulose, the degree of polymerization is preferably in the range of 250 to 400. When the cellulose ester resin is acetylated cellulose, the degree of acetylation is preferably in the range of 54.0 to 62.5 mass%, more preferably in the range of 58.0 to 62.5 mass%. When the polymerization degree and acetylation degree of the cellulose acetate are within the above ranges, a film having excellent mechanical properties can be obtained. In the present invention, it is more preferable to use so-called cellulose triacetate. The acetylation degree referred to in the present invention is the mass ratio of acetic acid produced by saponifying the cellulose acetate to the total amount of the cellulose acetate.

[0063] The "average degree of polymerization" can be measured according to the intrinsic viscosity method of Uda et al. (Uda Kazuo, Saito Hideo, "Sen'i Gakkaishi Journal," Vol. 18, No. 1, pp. 105-120, 1962). Specifically, 0.2 g of bone-dried cellulose ester is precisely weighed and dissolved in 100 ml of a mixed solvent of methylene chloride:ethanol = 9:1 (mass ratio). The solution is measured using an Ostwald viscometer in a thermostatic water bath at 25°C to measure the number of seconds it takes for the solution to fall, and the average degree of polymerization is calculated according to the following formula (1). Average degree of polymerization=[η] / K m ... [Formula 1] [η]=(lnη rel ) / C η rel =T / T0 K m =6×10 -4 T: Fall time of the measurement sample (seconds) T0: solvent drop time (seconds) C: concentration of sample (g / l)

[0064] The number average molecular weight of the cellulose ester resin is preferably in the range of 50,000 to 300,000, and more preferably in the range of 60,000 to 200,000.

[0065] The cellulose ester resin may be a commercially available product, and examples of the commercially available product include cellulose diacetates such as "L-20" (average acetyl substitution degree 2.41, average polymerization degree 145), "L-30" (average acetyl substitution degree 2.41, average polymerization degree 160), "L-50" (average acetyl substitution degree 2.41, average polymerization degree 180), and "L-70" (average acetyl substitution degree 2.41, average polymerization degree 190), all manufactured by Daicel Corporation; "LT-35" (average acetyl substitution degree 2.87, average polymerization degree 270), "L Examples of cellulose acetate butyrates include cellulose triacetates such as "T-105" (average acetyl substitution degree 2.87, average polymerization degree 350) manufactured by Eastman Chemical Co., Ltd.; cellulose acetate propionates such as "CAP-482-20" (average acetyl content 2.5%, average propionyl content 46.0%, number average molecular weight 75,000) manufactured by Eastman Chemical Co., Ltd.; and cellulose acetate butyrates such as "CAB-381-20" (average acetyl content 13.5%, average butyryl content 37.0%, number average molecular weight 70,000) manufactured by Eastman Chemical Co., Ltd.

[0066] The cellulose ester resin may be a commercially available product or may be a synthesized product. The cellulose ester resin may be synthesized by a known method, and the synthesis method is not particularly limited.

[0067] The cellulose ester resin can be synthesized, for example, by esterifying all or some of the hydroxyl groups at the 2nd, 3rd, and 6th positions of glucose residues in cellulose molecules of wood pulp (e.g., softwood pulp, hardwood pulp, etc.), cotton linter, etc.

[0068] When acetylated cellulose is obtained as a cellulose ester resin, it can be produced by a known esterification method in which cellulose is reacted with a predetermined amount of an acetylating agent, and can be synthesized through an aging step, a precipitation step, a purification step, a drying step, etc. as necessary.

[0069] For example, it can be synthesized through a series of steps, including (1) a pretreatment / activation step in which pulp (cellulose) is crushed and then pretreated / activated by spraying and mixing monocarboxylic acids, mainly acetic acid, followed by an esterification step in which monocarboxylic anhydrides, mainly acetic anhydride, are used with an esterification catalyst such as sulfuric acid to prepare cellulose triacetate, (2) an aging step in which the obtained cellulose triacetate is adjusted to the desired degree of acyl substitution by hydrolysis, and (3) a post-treatment step in which the obtained acetylated cellulose is filtered, separated by precipitation, washed with water, dehydrated, and dried.

[0070] The conditions such as the type of the esterification catalyst, the amount used, the reaction temperature, and the aging temperature are not particularly limited. When an acid such as sulfuric acid is used as the esterification catalyst, the product may be treated with a base such as a monocarboxylic acid metal salt to neutralize the remaining acid. The type of base used for neutralization is not particularly limited.

[0071] (Other additives) The cellulose ester resin composition of the present invention may contain other additives. Examples of the other additives include other modifiers other than the cellulose ester resin modifier of the present invention, thermoplastic resins, ultraviolet absorbers, matting agents, stabilizers, anti-degradants (e.g., antioxidants, peroxide decomposers, radical inhibitors, metal deactivators, acid scavengers, etc.), dyes, etc.

[0072] Examples of the other modifiers include ester compounds other than the polyol ester compound and diester compound of the present invention, phosphoric acid esters such as triphenyl phosphate (TPP), tricresyl phosphate, and cresyl diphenyl phosphate, phthalic acid esters such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, and di-2-ethylhexyl phthalate, ethyl phthalyl ethyl glycolate, butyl phthalyl butyl glycolate, trimethylolpropane tribenzoate, pentaerythritol tetraacetate, and acetyl tributyl citrate. The cellulose ester resin composition of the present invention preferably does not contain any of the above-mentioned other modifiers.

[0073] Examples of the thermoplastic resin include polyester resins other than the ester resin of the present invention, polyester ether resins, polyurethane resins, acrylic resins, epoxy resins, and toluenesulfonamide resins.

[0074] Examples of the ultraviolet absorber include oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, and nickel complex salt compounds. The ultraviolet absorber is preferably used in an amount of 0.01 to 2 parts by mass relative to 100 parts by mass of the cellulose ester resin.

[0075] Examples of the matting agent include silicon oxide, titanium oxide, aluminum oxide, calcium carbonate, calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, kaolin, and talc. The matting agent is preferably used in an amount of 0.1 to 0.3 parts by mass relative to 100 parts by mass of the cellulose ester resin.

[0076] Examples of the stabilizer include calcium hydroxide, calcium carbonate, and fatty acid metal salts. The stabilizer is preferably used in an amount of 50 to 5000 ppm relative to 100 parts by mass of the cellulose ester resin.

[0077] The dye is not particularly limited in type or amount as long as the effect of the present invention is not impaired.

[0078] (Molded body and optical film) Among the molded articles obtainable using the cellulose ester resin composition of the present invention, the cellulose ester resin composition of the present invention is suitably used for producing optical films. The optical film can be obtained by producing an unstretched film by a method such as extrusion molding or cast molding using a composition containing a cellulose ester resin and the polyester of the present invention, and then stretching the unstretched film.

[0079] The unstretched film can be produced by a solution casting method (solvent casting method), which is a cast molding method. The solution casting method will be described in detail below. The unstretched film obtained by the solution casting method exhibits substantially optical isotropy. The film exhibiting optical isotropy can be used for optical materials such as liquid crystal displays, and is particularly useful as a protective film for polarizing plates. Furthermore, the film obtained by the method is less likely to develop irregularities on its surface, and has excellent surface smoothness.

[0080] The solution casting method includes, for example, a first step in which a cellulose ester resin and the modifier of the present invention are dissolved in a solvent and the resulting resin solution is cast onto a metal support; a second step in which the organic solvent contained in the cast resin solution is evaporated and dried to form a film; and a third step in which the film formed on the metal support is peeled off from the metal support and dried by heating.

[0081] The organic solvent that can be used to dissolve the cellulose ester resin and the modifier of the present invention is not particularly limited as long as it can dissolve them. For example, it is preferable to use organic halogen compounds such as chloroform, methylene dichloride, and methylene chloride, or dioxolanes as good solvents.

[0082] A poor solvent such as methanol, ethanol, 2-propanol, n-butanol, cyclohexane, or cyclohexanone may be used in combination with the good solvent. The mixing ratio of the good solvent to the poor solvent is preferably in the range of good solvent / poor solvent=75 / 25 to 95 / 5 by mass ratio.

[0083] The concentration of the cellulose ester resin in the resin solution is preferably in the range of 10 to 50% by mass, more preferably in the range of 10 to 35% by mass.

[0084] The metal support used in the first step may be, for example, an endless belt-shaped or drum-shaped metal support, such as a stainless steel support with a mirror-finished surface.

[0085] When the resin solution is cast onto the metal support, it is preferable to use a resin solution that has been filtered to prevent foreign matter from being mixed into the resulting film.

[0086] The drying method in the second step is not particularly limited, but examples thereof include a method in which air having a temperature in the range of 30 to 50°C is blown onto the upper and / or lower surfaces of the metal support to evaporate 50 to 80 mass % of the organic solvent contained in the cast resin solution, thereby forming a film on the metal support.

[0087] Next, in the third step, the film formed in the second step is peeled off from the metal support and heat-dried under a temperature condition higher than that in the second step. As the heat-drying method, for example, a method of gradually increasing the temperature under a temperature condition of 100 to 160°C is preferred because it can achieve good dimensional stability. By heat-drying under the above temperature condition, the organic solvent remaining in the film after the second step can be almost completely removed.

[0088] In the first to third steps, the solvent can be recovered and reused.

[0089] A stretched film is obtained by stretching the resulting unstretched film. The stretching method is not particularly limited, and a stretched film can be obtained by longitudinal uniaxial stretching in the mechanical flow direction or transverse uniaxial stretching in the direction perpendicular to the mechanical flow direction. A stretched film can also be obtained by free-end uniaxial stretching. Free-end uniaxial stretching refers to longitudinal stretching in a state in which there are no components such as a conveying roller, a supporting plate, or a supporting belt that support or contact the film between a pair of stretching rollers, and the film can freely contract and expand in the width direction. Alternatively, the unstretched film can be biaxially stretched by a method such as sequential biaxial stretching using roll stretching and tenter stretching, simultaneous biaxial stretching using tenter stretching, or biaxial stretching using tubular stretching to obtain a stretched film.

[0090] The stretching ratio in the stretching is not particularly limited, but is preferably 1% to 1000% in at least one direction. The stretching ratio in at least one direction is preferably 3% to 600%, more preferably 5% to 300%, and even more preferably 10% to 300%. By setting the stretching ratio within this range, a preferred stretched film can be obtained in terms of birefringence, heat resistance, and strength.

[0091] The thickness of the stretched film is preferably in the range of 20 to 200 μm, more preferably in the range of 25 to 150 μm, and particularly preferably in the range of 25 to 120 μm.

[0092] The stretched film can be suitably used as an optical material, for example, a polarizing plate protective film for polarized lenses or sunglasses, a polarizing plate protective film used in displays such as liquid crystal displays, plasma displays, organic EL displays, field emission displays, and rear projection televisions, a retardation film such as a quarter wave plate, a half wave plate, a viewing angle control film, or a liquid crystal optical compensation film, or a display front panel. [Example]

[0093] The present invention will be specifically described below with reference to examples and comparative examples. The present invention is not limited to the following examples.

[0094] In the examples of the present application, the acid value and hydroxyl value were evaluated by the following methods. [Acid value measurement method] Measurement was carried out according to the method of JIS K0070-1992. [Method for measuring hydroxyl value] Measurement was carried out according to the method of JIS K0070-1992.

[0095] In the examples of the present application, the number average molecular weight of the polyester is a value calculated as polystyrene based on GPC measurement, and the measurement conditions are as follows. [GPC measurement conditions] Measurement equipment: Tosoh Corporation's high-speed GPC equipment "HLC-8320GPC" Column: Tosoh Corporation "TSK GURDCOLUMN SuperHZ-L" + Tosoh Corporation "TSK gel SuperHZM-M" + Tosoh Corporation "TSK gel SuperHZM-M" + Tosoh Corporation "TSK gel SuperHZ-2000" + Tosoh Corporation "TSK gel SuperHZ-2000" Detector: RI (differential refractometer) Data processing: Tosoh Corporation's "EcoSEC Data Analysis Version 1.07" Column temperature: 40℃ Developing solvent: tetrahydrofuran Flow rate: 0.35mL / min Measurement sample: 7.5 mg of the sample was dissolved in 10 ml of tetrahydrofuran, and the resulting solution was filtered through a microfilter to prepare a measurement sample. Sample injection volume: 20 μl Standard sample: In accordance with the measurement manual for the above-mentioned "HLC-8320GPC," the following monodisperse polystyrene with known molecular weight was used.

[0096] (monodisperse polystyrene) Tosoh Corporation "A-300" Tosoh Corporation "A-500" Tosoh Corporation "A-1000" Tosoh Corporation "A-2500" Tosoh Corporation "A-5000" "F-1" manufactured by Tosoh Corporation "F-2" manufactured by Tosoh Corporation "F-4" manufactured by Tosoh Corporation "F-10" manufactured by Tosoh Corporation "F-20" manufactured by Tosoh Corporation "F-40" manufactured by Tosoh Corporation "F-80" manufactured by Tosoh Corporation Tosoh Corporation "F-128" Tosoh Corporation "F-288"

[0097] (Synthesis Example 1: Preparation of ester compound (C1)) A 0.5-liter four-neck flask was charged with 112 g of trimethylolpropane, 274 g of benzoic acid, 36 g of 2-ethylhexanoic acid, and 0.01 g of tetraisopropoxy titanate as a catalyst. The mixture was then heated stepwise to 220°C and reacted for approximately 20 hours (molar ratio of benzoic acid to 2-ethylhexanoic acid = 90:10). After the reaction, unreacted raw materials were distilled off under reduced pressure at 200°C. After the reduction in pressure was completed, the reaction product was filtered to obtain ester compound (A1) as a pale yellow liquid. The ester compound (C1) had a number average molecular weight of 380, an acid value of 0.2, and a hydroxyl value of 21.

[0098] (Synthesis Example 2: Preparation of ester compound (C2)) A 0.5-liter four-neck flask was charged with 115 g of trimethylolpropane, 249 g of benzoic acid, 74 g of 2-ethylhexanoic acid, and 0.01 g of tetraisopropoxy titanate as a catalyst. The mixture was then heated stepwise to 220°C and reacted for approximately 25 hours (molar ratio of benzoic acid to 2-ethylhexanoic acid = 80:20). After the reaction, unreacted raw materials were distilled off under reduced pressure at 200°C. After the reduction in pressure was completed, the reaction product was filtered to obtain ester compound (A2) as a pale yellow liquid. The ester compound (C2) had a number average molecular weight of 390, an acid value of 0.2, and a hydroxyl value of 21.

[0099] (Synthesis Example 3: Preparation of ester compound (C3)) A 0.5-liter four-neck flask was charged with 115 g of trimethylolpropane, 218 g of benzoic acid, 110 g of 2-ethylhexanoic acid, and 0.01 g of tetraisopropoxy titanate as a catalyst. The temperature was then gradually increased to 220°C and the mixture was reacted for approximately 20 hours (molar ratio of benzoic acid to 2-ethylhexanoic acid = 70:30). After the reaction, unreacted raw materials were distilled off under reduced pressure at 200°C. After the reduction in pressure was completed, the reaction product was filtered to obtain ester compound (A3) as a pale yellow liquid. The ester compound (C3) had a number average molecular weight of 400, an acid value of 0.1, and a hydroxyl value of 22.

[0100] (Synthesis Example 4: Preparation of ester compound (C4)) A 0.5-liter four-neck flask was charged with 115 g of trimethylolpropane, 249 g of benzoic acid, 45 g of n-butanoic acid, and 0.01 g of tetraisopropoxy titanate as a catalyst. The temperature was then gradually increased to 220°C and the mixture was reacted for approximately 21 hours (molar ratio of benzoic acid to n-butanoic acid = 80:20). After the reaction, unreacted raw materials were distilled off under reduced pressure at 200°C. After the reduction in pressure was completed, the reaction product was filtered to obtain the ester compound (C4) as a pale yellow liquid. The ester compound (C4) had a number average molecular weight of 380, an acid value of 0.1, and a hydroxyl value of 24.

[0101] (Synthesis Example 5: Preparation of ester compound (C5)) A 0.5-liter four-neck flask was charged with 79 g of glycerin, 249 g of benzoic acid, 74 g of 2-ethylhexanoic acid, and 0.01 g of tetraisopropoxy titanate as a catalyst. The mixture was then heated stepwise to 220°C and reacted for approximately 25 hours (molar ratio of benzoic acid to 2-ethylhexanoic acid = 80:20). After the reaction, unreacted raw materials were distilled off under reduced pressure at 200°C. After the reduction in pressure was completed, the reaction product was filtered to obtain the ester compound (C5) as a pale yellow liquid. The ester compound (C5) had a number average molecular weight of 390, an acid value of 0.1, and a hydroxyl value of 20.

[0102] (Synthesis Example 6: Preparation of ester compound (C6)) A 0.5-liter four-neck flask was charged with 89 g of pentaerythritol, 254 g of benzoic acid, 75 g of 2-ethylhexanoic acid, and 0.01 g of tetraisopropoxy titanate as a catalyst. The mixture was then heated stepwise to 220°C and reacted for approximately 29 hours (molar ratio of benzoic acid to 2-ethylhexanoic acid = 80:20). After the reaction, unreacted raw materials were distilled off under reduced pressure at 200°C. After the reduction in pressure was completed, the reaction product was filtered to obtain the ester compound (C6) as a pale yellow liquid. The ester compound (C6) had a number average molecular weight of 510, an acid value of 0.4, and a hydroxyl value of 28.

[0103] (Synthesis Example 7: Preparation of ester compound (C7)) A 0.5-liter four-neck flask was charged with 110 g of dipentaerythritol, 252 g of benzoic acid, 74 g of 2-ethylhexanoic acid, and 0.01 g of tetraisopropoxy titanate as a catalyst. The mixture was then heated stepwise to 220°C and reacted for approximately 32 hours (molar ratio of benzoic acid to 2-ethylhexanoic acid = 80:20). After the reaction, unreacted raw materials were distilled off under reduced pressure at 200°C. After the reduction in pressure was completed, the reaction product was filtered to obtain the ester compound (C7) as a pale yellow liquid. The ester compound (C7) had a number average molecular weight of 850, an acid value of 0.3, and a hydroxyl value of 25.

[0104] (Comparative Synthesis Example 1: Preparation of Ester Compound (C1')) A 0.5-liter four-neck flask was charged with 113 g of trimethylolpropane, 152 g of benzoic acid, 179 g of 2-ethylhexanoic acid, and 0.01 g of tetraisopropoxy titanate as a catalyst. The temperature was then gradually increased to 220°C and the mixture was reacted for approximately 25 hours (molar ratio of benzoic acid to 2-ethylhexanoic acid = 50:50). After the reaction, unreacted raw materials were distilled off under reduced pressure at 200°C. After the reduction in pressure was completed, the reaction product was filtered to obtain the ester compound (C1') as a pale yellow liquid. The ester compound (C1′) had a number average molecular weight of 430, an acid value of 0.1, and a hydroxyl value of 28.

[0105] (Comparative Synthesis Example 2: Preparation of Ester Compound (C2')) A 0.5-liter four-neck flask was charged with 115 g of trimethylolpropane, 311 g of benzoic acid, and 0.01 g of tetraisopropoxy titanate as a catalyst, and the mixture was heated stepwise to 220°C and reacted for approximately 25 hours. After the reaction, unreacted raw materials were distilled off under reduced pressure at 200°C. After the reduction in pressure was completed, the reaction product was filtered to obtain a pale yellow liquid ester compound (C2'). The ester compound (C2′) had a number average molecular weight of 370, an acid value of 0.1, and a hydroxyl value of 23.

[0106] (Synthesis Example 8: Preparation of diester compound (D1)) A 2-liter four-neck flask was charged with 900 g of benzoic acid, 547 g of dipropylene glycol, and 0.74 g of tetraisopropoxy titanate as a catalyst, and the mixture was heated to 220°C and reacted for 11 hours. After the reaction, the unreacted glycol was distilled off under reduced pressure at 200°C. After the outflow of unreacted alcohol ceased, the reduced pressure was released, the temperature was lowered, and the reaction product was filtered to obtain a pale yellow liquid diester compound (D1). The diester compound (D1) had a number average molecular weight of 340, an acid value of 0.2, and a hydroxyl value of 5.

[0107] (Synthesis Example 9: Preparation of diester compound (D2)) A 2-liter four-neck flask was charged with 900 g of benzoic acid, 294 g of propylene glycol, 50 g of dipropylene glycol, and 0.62 g of tetraisopropoxy titanate as a catalyst, and the mixture was then heated to 220°C and reacted for 14 hours. After the reaction, the unreacted glycol was distilled off under reduced pressure at 200°C. After the outflow of unreacted alcohol ceased, the reduced pressure was released, the temperature was lowered, and the reaction product was filtered and collected, yielding a diester compound (D2) as a clear yellow liquid. The diester compound (D2) had a number average molecular weight of 290, an acid value of 0.1, and a hydroxyl value of 7.

[0108] (Synthesis Example 10: Preparation of polyester polyol (P1-1)) A 0.5-liter four-neck flask was charged with 171 g of 1,2-propylene glycol, 62 g of isophthalic acid, 164 g of adipic acid, and 0.02 g of tetraisopropyl titanate as a catalyst. The mixture was stirred under a nitrogen stream and gradually heated to 220°C. A condensation reaction was then carried out at 220°C for 10 hours, and it was confirmed that the acid value had reached 1.0 or less. Excess glycol was removed under reduced pressure at 150°C to obtain a polyester polyol (P1-1). The obtained polyester polyol (P1-1) was a pale yellow liquid at room temperature, and had an acid value of 0.2, a hydroxyl value of 143, and a number average molecular weight of 860.

[0109] (Synthesis Example 11: Preparation of polyester polyol (P1-2)) A 5-liter, four-neck flask was charged with 1,817 g of 1,2-propylene glycol, 78 g of ethylene glycol, 2,608 g of terephthalic acid, and 0.27 g of tetraisopropyl titanate as a catalyst. The mixture was stirred under a nitrogen stream and gradually heated to 230°C. A condensation reaction was then carried out at 230°C for 20 hours, and it was confirmed that the acid value had reached 1.0 or less. Excess glycol was removed under reduced pressure at 160°C to obtain a polyester polyol (P1-2). The obtained polyester polyol (P1-2) was a pale yellow solid at room temperature, and had an acid value of 0.8, a hydroxyl value of 147, and a number average molecular weight of 870.

[0110] (Synthesis Example 12: Preparation of polyester polyol (P1-3)) A 3-liter, four-neck flask was charged with 922 g of 1,2-propylene glycol, 944 g of phthalic anhydride, 310 g of adipic acid, and 0.13 g of tetraisopropyl titanate as a catalyst. The mixture was stirred under a nitrogen stream and gradually heated to 220°C. A condensation reaction was then carried out at 220°C for 10 hours, and it was confirmed that the acid value had reached 1.0 or less. Excess glycol was removed under reduced pressure at 150°C to obtain a polyester polyol (P1-3). The obtained polyester polyol (P1-3) was a pale yellow liquid at room temperature, and had an acid value of 0.5, a hydroxyl value of 163, and a number average molecular weight of 790.

[0111] (Synthesis Example 13: Preparation of Polyester (P2-1)) A 3 L four-neck flask equipped with a thermometer, a stirrer, a nitrogen inlet tube, and a T-shaped distillation tube was charged with 132 g of adipic acid, 400 g of phthalic anhydride, 977 g of benzoic acid, 648 g of propylene glycol, and 0.130 g of tetraisopropoxytitanium, and the mixture was then heated stepwise to 220°C while stirring under a nitrogen stream. After a condensation reaction was carried out at 220°C for a total of 12 hours, the unreacted propylene glycol was removed under reduced pressure to obtain polyester (P2-1), which was a highly viscous liquid at room temperature. The polyester (P2-1) had an acid value of 0.1, a hydroxyl value of 8.0, and a number average molecular weight (Mn) of 430.

[0112] (Synthesis Example 14: Preparation of Polyester (P2-2)) A 3-liter four-neck flask equipped with a thermometer, a stirrer, and a reflux condenser was charged with 554 g of dimethyl terephthalate, 476 g of propylene glycol, 817 g of para-toluic acid, and 0.130 g of tetraisopropyl titanate as an esterification catalyst, and the mixture was heated stepwise to 230°C while stirring under a nitrogen stream. After a condensation reaction was carried out at 230°C for a total of 19 hours, unreacted propylene glycol was removed under reduced pressure to obtain polyester (P2-2), which was a highly viscous liquid at room temperature. The resulting polyester (P2-2) had an acid value of 0.2, a hydroxyl value of 11, and a number average molecular weight (Mn) of 500.

[0113] (Synthesis Example 15: Preparation of Polyester (P2-3)) A 2-liter four-neck flask equipped with a thermometer, a stirrer, and a reflux condenser was charged with 374 g of isophthalic acid, 412 g of propylene glycol, 611 g of benzoic acid, and 0.08 g of tetraisopropyl titanate as a catalyst, and the mixture was heated stepwise to 230°C while stirring under a nitrogen stream. After a condensation reaction was carried out at 230°C for a total of 10 hours, the unreacted propylene glycol was removed under reduced pressure to obtain polyester (P2-3), which was a highly viscous liquid at room temperature. The resulting polyester (P2-3) had an acid value of 0.1, a hydroxyl value of 10, and a number average molecular weight (Mn) of 590.

[0114] (Examples 1-18 and Comparative Examples 1-8: Production and Evaluation of Cellulose Ester Films) A dope solution was obtained by dissolving 100 parts by mass of a commercially available cellulose ester resin A (cellulose triacetate, "LT-35" manufactured by Daicel Corporation), 900 parts by mass of methylene chloride, and 100 parts by mass of methanol in the amounts shown in Table 1. The dope solution obtained was cast on a glass plate, and the solvent was evaporated (dried) to obtain a film with a thickness of approximately 60 μm. The obtained film was evaluated as follows, and the results are shown in Table 1-3.

[0115] (Examples 19-36 and Comparative Examples 9-16: Production and Evaluation of Cellulose Ester Films) A film was produced and evaluated in the same manner as in Example 1, except that cellulose ester resin B (cellulose diacetate, "L-50" manufactured by Daicel Corporation) was used instead of cellulose ester resin A. The results are shown in Tables 4-6.

[0116] (moisture permeability) The moisture permeability of the obtained film was measured under conditions of a temperature of 40°C and a relative humidity of 90% according to the method described in JIS Z 0208: 1976. The smaller the obtained value, the more excellent the moisture permeability resistance.

[0117] (transparency) The obtained film was punched out into 40 mm square test pieces using a punching machine, and the haze value was measured using a haze meter "NDH-5000" (manufactured by Nippon Denshoku Industries Co., Ltd.) The smaller the obtained haze value, the more excellent the transparency.

[0118] (Heat and humidity resistance) The obtained film was exposed to an environment of 85°C and a relative humidity of 90% (humid and hot environment) for 120 hours. The difference in film weight before and after the test was calculated as the wet heat loss. In addition, the haze value of the film after the wet heat test was measured, and the film appearance was evaluated according to the following criteria. No turbidity or foreign matter was observed on the film surface: ○ Turbidity and / or foreign matter can be seen on the film surface: ×

[0119] (Film production line contamination) Using the production line shown in Figure 1 of JP 2003-285342 A, the above dope solution was used to produce a cellulose ester film by operating for 8 hours a day for one month (including eight days of production suspension). After one month, the tenter (soft film drying zone) of the production line was visually inspected for the presence of ester compound precipitation derived from the modifier, and evaluated according to the following criteria. No ester compound precipitation was observed: ○ Precipitation of ester compounds was confirmed: ×

[0120] [Table 1]

[0121] [Table 2]

[0122] [Table 3]

[0123] [Table 4]

[0124] [Table 5]

[0125] [Table 6]

[0126] The results in Tables 1-6 indicate that the modifier of the present invention has the same modifying effect as the modifier of aliphatic polyol and aromatic monocarboxylic acid (ester compound (C2')), and overcomes the drawbacks of the modifier of aliphatic polyol and aromatic monocarboxylic acid, such as bloomout of the modifier and contamination of production equipment.

Claims

1. A modifier for cellulose ester resins, comprising a polyol ester compound having a tri- to hexa-hydric aliphatic polyol, an aromatic monocarboxylic acid, and an aliphatic monocarboxylic acid as reaction components, The cellulose ester resin modifier satisfies the molar ratio of the aromatic monocarboxylic acid to the aliphatic monocarboxylic acid of aromatic monocarboxylic acid:aliphatic monocarboxylic acid=95:5 to 60:

40.

2. 2. The modifier for cellulose ester resins according to claim 1, wherein the aliphatic polyol is a tri- to hexa-valent aliphatic polyol having 2 to 12 carbon atoms.

3. The cellulose ester resin modifier according to claim 1, wherein the aliphatic polyol is at least one selected from the group consisting of trimethylolpropane, sorbitol, 1,4-sorbitan, erythritol, pentaerythritol, dipentaerythritol, tripentaerythritol, 1,2,4-butanetriol, 1,2,5-pentanetriol, 2-methyl-1,2,3-propanetriol, 2-methyl-1,2,4-butanetriol, and glycerin.

4. 2. The modifier for cellulose ester resins according to claim 1, wherein the aromatic monocarboxylic acid is an aromatic monocarboxylic acid having 6 to 12 carbon atoms.

5. 2. The modifier for cellulose ester resins according to claim 1, wherein the aliphatic monocarboxylic acid is an aliphatic monocarboxylic acid having 4 to 10 carbon atoms.

6. 2. The modifier for cellulose ester resins according to claim 1, further comprising a diester compound having an aliphatic diol and an aromatic monocarboxylic acid as reaction components.

7. 7. The modifier for cellulose ester resins according to claim 6, wherein the aliphatic diol is an aliphatic diol having 2 to 6 carbon atoms.

8. The cellulose ester resin modifier according to claim 6, wherein the aliphatic diol is at least one selected from the group consisting of ethylene glycol, neopentyl glycol, propylene glycol, hexanediol, polyethylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, diethylene glycol, dipropylene glycol, triethylene glycol, 1,4-cyclohexanedimethanol, D-isosorbide, L-isosorbide, isomannide, erythritan, and 1,4-dihydroxy-2-butene.

9. 7. The modifier for cellulose ester resins according to claim 6, wherein the aromatic monocarboxylic acid is an aromatic monocarboxylic acid having 6 to 12 carbon atoms.

10. 7. The modifier for cellulose ester resins according to claim 6, wherein the mass ratio of the polyol ester compound to the diester compound is polyol ester compound:diester compound=99:1 to 40:

60.

11. 2. The modifier for cellulose ester resin according to claim 1, which contains a polyester polyol represented by the following general formula (1): 【Chemistry 1】 (In the general formula (1), G １ is an aliphatic diol residue having 2 to 12 carbon atoms or an aromatic diol residue having 6 to 18 carbon atoms, A １ is an aliphatic dicarboxylic acid residue having 2 to 12 carbon atoms or an aromatic dicarboxylic acid residue having 6 to 14 carbon atoms, n represents the number of repetitions. However, for each repetition, G １ may be the same or different, and A １ may be the same or different.)

12. The modifier for cellulose ester resin according to claim 11, wherein the mass ratio of the polyol ester compound to the polyester polyol represented by the general formula (1) is polyol ester compound: polyester polyol represented by the general formula (1) = 99:1 to 25:

75.

13. 2. The modifier for cellulose ester resin according to claim 1, which comprises a polyester represented by the following general formula (2): 【Chemistry 2】 (In the general formula (2), G ２ is an aliphatic diol residue having 2 to 12 carbon atoms or an aromatic diol residue having 6 to 18 carbon atoms, A ２ is an aliphatic dicarboxylic acid residue having 2 to 12 carbon atoms or an aromatic dicarboxylic acid residue having 6 to 14 carbon atoms, B １ and B ２ are each independently an aliphatic monocarboxylic acid residue having 1 to 8 carbon atoms or an aromatic monocarboxylic acid residue having 6 to 12 carbon atoms, m represents the number of repetitions. However, for each repetition, G ２ may be the same or different, and A ２ may be the same or different.)

14. The modifier for cellulose ester resin according to claim 13, wherein the mass ratio of the polyol ester compound to the polyester represented by the general formula (2) is polyol ester compound: polyester represented by the general formula (2) = 99:1 to 25:

75.

15. A cellulose ester resin composition comprising a cellulose ester resin and the modifier for cellulose ester resins according to any one of claims 1 to 14.

16. 16. The cellulose ester resin composition according to claim 15, wherein the cellulose ester resin modifier is contained in an amount ranging from 1 to 30 parts by mass relative to 100 parts by mass of the cellulose ester resin.

17. A molded article of the cellulose ester resin composition according to claim 15.

18. An optical film obtained by using the cellulose ester resin composition according to claim 15.

19. A display device comprising the optical film according to claim 18.

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