阅读说明：本技术 纤维素酯树脂用添加剂以及纤维素酯组合物 (Additive for cellulose ester resin and cellulose ester composition ) 是由 尾崎知代 田尻裕辅 于 2019-08-08 设计创作，主要内容包括：本发明提供一种可提高保存稳定性的纤维素酯树脂用添加剂。具体而言,使用包含选自脂肪酸金属盐、金属氢氧化物和碳酸金属盐中的一种以上金属化合物的纤维素酯树脂用添加剂。(The invention provides an additive for cellulose ester resin, which can improve storage stability. Specifically, an additive for cellulose ester resins containing one or more metal compounds selected from fatty acid metal salts, metal hydroxides, and metal carbonates is used.)

1. An additive for cellulose ester resins, comprising one or more metal compounds selected from the group consisting of fatty acid metal salts, metal hydroxides, and metal carbonates.

2. The additive for cellulose ester resins according to claim 1, wherein,

the metal compound is a metal salt of a fatty acid having 2 to 30 carbon atoms.

3. The additive for cellulose ester resins according to claim 1 or 2, wherein,

the metal of the metal compound is selected from the group consisting of lithium, sodium, aluminum, calcium, zinc, and barium.

4. The additive for cellulose ester resins according to any one of claims 1 to 3, wherein,

the metal of the metal compound is calcium or barium.

5. The additive for cellulose ester resins according to any one of claims 1 to 4, which is used in an amount of 10 to 3000ppm as added to a cellulose ester resin.

6. The additive for cellulose ester resins according to any one of claims 1 to 5, which is used in combination with a polyester-based additive comprising a polyester containing a polybasic acid and a polyhydric alcohol as essential raw materials.

7. The additive for cellulose ester resins according to claim 6, wherein,

the ends of the polyester are terminated by a residue of a monocarboxylic acid or a residue of a monohydric alcohol.

8. The additive for cellulose ester resins according to claim 6 or 7, wherein,

the polyester-based additive further comprises an ester compound comprising a polybasic acid and a monohydric alcohol, or a polyhydric alcohol and a monocarboxylic acid as essential raw materials.

9. The additive for cellulose ester resins according to claim 8, wherein,

the ester compound is a diester.

10. A cellulose ester resin composition comprising the additive for cellulose ester resins according to any one of claims 6 to 9 and a cellulose ester resin.

11. A molded article of the cellulose ester resin composition according to claim 10.

12. The molded article according to claim 11, which is an optical film.

Technical Field

The present invention relates to an additive for cellulose ester resins and a cellulose ester composition.

Background

Cellulose esters are widely used as optical films such as films for protecting polarizing films used for liquid crystal displays and polarized sunglasses lenses because of their transparency, optical isotropy, and toughness. In addition, cellulose ester films have moderate moisture permeability, and thus are widely used because they are easily adhered to a polarizing film (polyvinyl alcohol (PVA)/iodine) using a water gel. For the purpose of controlling a plasticizer and moisture permeability, a phosphate ester or an ester compound such as triphenyl phosphate (TPP) is used in the cellulose ester film (patent documents 1 and 2).

On the other hand, it is known that cellulose ester undergoes hydrolysis slowly during long-term storage, and the rate of hydrolysis is further accelerated in a hot and humid environment. In particular, when a phosphate such as triphenyl phosphate (TPP) is used, hydrolysis is promoted, and the long-term stability is poor. From the viewpoint of improving the stability of cellulose esters as compared with conventional plasticizers such as phosphoric acid esters, aliphatic polyesters and phthalic acid polyesters are used, but the long-term stability of the cellulose ester composition is insufficient.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-151699

Patent document 2: international publication No. 2010/087219 pamphlet

Disclosure of Invention

Problems to be solved by the invention

It is desired to develop a cellulose ester resin which can inhibit hydrolysis for a long period of time even under a severe environment.

The invention provides an additive for cellulose ester resin capable of improving storage stability and a cellulose ester composition with improved storage stability.

Means for solving the problems

The present inventors have conducted studies on various means, and as a result, have found that hydrolysis of a cellulose ester resin under a moist heat condition can be suppressed by adding a specific metal compound to the cellulose ester resin together with a polyester-based additive, and have accomplished the present invention.

The present invention relates to the following.

[1] An additive for cellulose ester resins, comprising one or more metal compounds selected from the group consisting of fatty acid metal salts, metal hydroxides, and metal carbonates.

[2] The additive for cellulose ester resins according to [1], wherein the metal compound is a metal salt of a fatty acid having 2 to 30 carbon atoms.

[3] The additive for cellulose ester resin according to [1] or [2], wherein the metal of the metal compound is selected from the group consisting of lithium, sodium, aluminum, calcium, zinc and barium.

[4] The additive for cellulose ester resins according to any one of [1] to [3], wherein the metal of the metal compound is calcium or barium.

[5] The additive for cellulose ester resins according to any one of [1] to [4], which is used for being added to a cellulose ester resin at a content of 10 to 3000 ppm.

[6] The additive for cellulose ester resins according to any one of [1] to [5], which is used in combination with a polyester-based additive comprising a polyester containing a polybasic acid and a polyhydric alcohol as essential raw materials.

[7] The additive for cellulose ester resins according to [6], wherein the ends of the polyester are terminated with a residue of monocarboxylic acid or a residue of monohydric alcohol.

[8] The additive for cellulose ester resins according to [6] or [7], wherein the polyester-based additive further comprises an ester compound comprising a polybasic acid and a monohydric alcohol, or a polyhydric alcohol and a monocarboxylic acid as essential raw materials.

[9] The additive for cellulose ester resins according to [8], wherein the ester compound is a diester.

[10] A cellulose ester resin composition comprising the additive for cellulose ester resins according to any one of [6] to [9] and a cellulose ester resin.

[11] A molded article of the cellulose ester resin composition according to [10 ].

[12] The molded article according to [11], which is an optical film.

Effects of the invention

According to the present invention, an additive for cellulose ester resins which can improve storage stability can be provided

Detailed Description

Hereinafter, one embodiment of the present invention will be described in detail. The present invention is not limited to the following embodiments, and can be carried out with appropriate modifications within a range not to impair the effects of the present invention.

[ additive for cellulose ester resin ]

The additive for cellulose ester resins of the present invention contains one or more metal compounds selected from the group consisting of fatty acid metal salts, metal hydroxides, and metal carbonates.

The additive for cellulose ester resins of the present invention comprises a metal compound selected from the group consisting of a fatty acid salt of a metal, a hydroxide of a metal and a carbonate of a metal.

[ Metal ]

In one embodiment of the present invention, as the metal contained in the metal compound, one or more metals selected from the group consisting of alkali metals, alkaline earth metals, zinc, aluminum, cobalt, nickel, manganese, zirconium, lead, and bismuth can be used. Examples of the alkali metal include lithium, sodium, and potassium. Examples of the alkaline earth metal include calcium and barium. In the present embodiment, lithium, sodium, aluminum, calcium, zinc, and barium are preferably used, and calcium and barium are particularly preferably used.

[ fatty acid ]

The fatty acid metal salt in one embodiment of the present invention is preferably a salt of a fatty acid having 2 to 30 carbon atoms and a metal, more preferably a salt of a fatty acid having 4 to 28 carbon atoms and a metal, and still more preferably a salt of a fatty acid having 6 to 22 carbon atoms and a metal. In addition, as the fatty acid, saturated fatty acids, unsaturated fatty acids, and derivatives thereof can be used, but saturated fatty acids are preferably used. Examples of the fatty acid include, but are not limited to, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, adipic acid, enanthic acid, caprylic acid, 2-ethylhexanoic acid, pelargonic acid, capric acid, sebacic acid, neodecanoic acid, undecanoic acid, lauric acid, tridecanoic acid, myristic acid, pentadecanoic acid, palmitic acid, palmitoleic acid, heptadecanoic acid, stearic acid, 12-hydroxystearic acid, nonadecanoic acid, heneicosanoic acid, tricosanoic acid, oleic acid, vaccenic acid, linoleic acid, linolenic acid, eleostearic acid, arachic acid, midic acid, arachidonic acid, behenic acid, lignoceric acid, nervonic acid, cerotic acid, montanic acid, melissic acid, and derivatives thereof.

[ Metal hydroxide ]

In one embodiment of the present invention, a metal hydroxide such as sodium hydroxide, magnesium hydroxide, potassium hydroxide, calcium hydroxide, aluminum hydroxide, or barium hydroxide can be used as the metal compound.

[ Metal salts of carbonic acid ]

In one embodiment of the present invention, metal carbonates such as lithium carbonate, sodium carbonate, magnesium carbonate, potassium carbonate, calcium carbonate, and barium carbonate can be used as the metal compound.

[ polyester-based additive ]

In one embodiment of the present invention, the additive for cellulose ester resins is used in combination with a polyester-based additive containing a polybasic acid and a polyhydric alcohol as essential raw materials. In the present embodiment, the polyester-based additive is an additive containing a polyester as a main component, and is an additive containing a polyester in an amount of at least 50 parts by mass, preferably at least 60 parts by mass, and more preferably at least 65 parts by mass, based on 100 parts by mass of the polyester-based additive.

[ polyester ]

The polyester in the present embodiment uses a polybasic acid and a polyhydric alcohol as essential raw materials.

(polybasic acid)

Examples of the polybasic acid used in the present embodiment include an aromatic polybasic carboxylic acid, an aliphatic polybasic carboxylic acid, a hydroxypolycarboxylic acid, and derivatives thereof.

Examples of the aromatic polycarboxylic acid include phthalic acid, isophthalic acid, terephthalic acid, phthalic anhydride, 1, 4-naphthalenedicarboxylic acid, 1, 8-naphthalenedicarboxylic acid, 2, 3-naphthalenedicarboxylic acid, 2, 6-naphthalenedicarboxylic acid, 2, 7-naphthalenedicarboxylic acid, 4' -biphenyldicarboxylic acid, trimellitic acid, trimesic acid, and pyromellitic acid, and these may be used alone or in combination of two or more. Among them, phthalic acid, isophthalic acid, and terephthalic acid are preferable from the viewpoint of obtaining a composition having excellent strength.

Examples of the aliphatic polycarboxylic acid include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, oxalic acid, decanedicarboxylic acid, fumaric acid, maleic acid, tetrahydrophthalic acid, hexahydrophthalic acid, 1, 2-dicarboxylcyclohexane, 1, 2-dicarboxylcyclohexene and the like, and two or more of them may be used alone or in combination. Among them, succinic acid, adipic acid, sebacic acid, and 1, 2-dicarboxycyclohexane are preferable from the viewpoint of excellent compatibility with the cellulose resin.

Examples of the hydroxypolycarboxylic acid include hydroxypolycarboxylic acids such as tartaric acid, tartronic acid, malic acid, and citric acid, and two or more of them may be used alone or in combination.

The number of carbon atoms of the polybasic acid other than the carbon atoms contained in the carboxyl group is not particularly limited, but is preferably 2 to 12, more preferably 2 to 8, and still more preferably 2 to 6.

(polyhydric alcohol)

Examples of the polyol used in the present embodiment include chain aliphatic polyols, cyclic aliphatic polyols, and aromatic polyols.

Examples of the chain aliphatic polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, 1, 2-propanediol, dipropylene glycol, tripropylene glycol, 1, 3-propanediol, 2-methyl-1, 3-propanediol, 2-butyl-2-ethylpropanediol, 1, 2-butanediol, 1, 3-butanediol, 1, 4-butanediol, 2, 3-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, neopentyl glycol, 1, 6-hexanediol, 2, 4-trimethyl-1, 3-pentanediol, 2-ethyl-1, 3-hexanediol, 1, 7-heptanediol, 1, 8-octanediol, 2-methyl-1, divalent aliphatic alcohols such as 8-octanediol, 1, 9-nonanediol, 1, 10-decanediol, and 1, 12-dodecanediol; trivalent aliphatic alcohols such as glycerin, 1, 2, 3-butanetriol, 1, 2, 4-butanetriol, 1, 2, 3-heptanetriol, 1, 2, 4-heptanetriol, 1, 2, 5-heptanetriol, 2, 3, 4-heptanetriol, and trimethylolpropane; tetravalent aliphatic alcohols such as pentaerythritol and erythritol; pentavalent aliphatic alcohols such as xylitol; and hexavalent aliphatic alcohols such as dipentaerythritol and sorbitol, and the like, and may be used alone or in combination of two or more. Among them, ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 1, 2-butanediol, 1, 3-butanediol, 2-methyl-1, 3-propanediol, 1, 5-pentanediol, diethylene glycol, and dipropylene glycol are preferable from the viewpoint of excellent compatibility with the cellulose resin.

Examples of the cyclic aliphatic polyol include 1, 2-cyclopentanediol, 1, 3-cyclopentanediol, cyclopentanedimethanol, cyclohexanediol, cyclohexanedimethanol, cycloheptanediol, cycloheptanedimethanol, hydrogenated bisphenol a, and the like, and two or more of these may be used alone or in combination.

Examples of the aromatic polyol include hydroquinone, resorcinol, bisphenol a, ethylene oxide adducts of bisphenol a, propylene oxide adducts, bisphenol F, ethylene oxide adducts of bisphenol F, propylene oxide adducts, biphenol, ethylene oxide adducts of biphenol, 1, 2-benzenedimethanol, 1, 3-benzenedimethanol, 1, 4-benzenedimethanol, and the like, and two or more thereof may be used alone or in combination.

The number of carbon atoms of the polyol is not particularly limited, but is preferably 2 to 12, more preferably 2 to 8, and still more preferably 2 to 4.

The number average molecular weight (Mn) of the polyester-based additive in one embodiment of the present invention is preferably in the range of 200 to 2000, more preferably in the range of 250 to 1500, and still more preferably in the range of 300 to 1200.

The number average molecular weight (Mn) is a value obtained in terms of polystyrene by Gel Permeation Chromatography (GPC) measurement. The measurement conditions of GPC are as follows.

[ GPC measurement conditions ]

A measuring device: high-speed GPC apparatus "HLC-8320 GPC" manufactured by Tosoh corporation "

Column: "TSK GURDCOLUMN SuperHZ-L" manufactured by Tosoh corporation, "TSK gel SuperHZM-M" manufactured by Tosoh corporation "+ TSK gel SuperHZ-2000" manufactured by Tosoh corporation "

A detector: RI (differential refractometer)

Data processing: "EcoSEC Data Analysis version 1.07" manufactured by Tosoh corporation "

Column temperature: 40 deg.C

Developing agent: tetrahydrofuran (THF)

Flow rate: 0.35 mL/min

Measurement of the sample: a7.5 mg sample was dissolved in 10ml of tetrahydrofuran, and the resulting solution was filtered through a microfilter to obtain a measurement sample.

Sample injection amount: 20 μ l

Standard sample: following the manual for the determination of "HLC-8320 GPC" mentioned above, the following monodisperse polystyrene of known molecular weight was used.

(monodisperse polystyrene)

"A-300" manufactured by Tosoh corporation "

"A-500" manufactured by Tosoh corporation "

"A-1000" manufactured by Tosoh corporation "

"A-2500" manufactured by Tosoh corporation "

"A-5000" manufactured by Tosoh corporation "

"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 "

"F-128" manufactured by Tosoh corporation "

"F-288" manufactured by Tosoh corporation "

The ends of the polyester of this embodiment may be capped with a residue of a monocarboxylic acid or a residue of a monohydric alcohol.

(monocarboxylic acid)

As the monocarboxylic acid used in the present embodiment, an aliphatic monocarboxylic acid, an alicyclic monocarboxylic acid, an aromatic monocarboxylic acid, or the like can be used.

Examples of the aliphatic monocarboxylic acid include acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, 2-ethylhexanoic acid, pelargonic acid, and derivatives thereof, and these may be used alone or in combination of two or more. Among them, acetic acid is preferable from the viewpoint of excellent compatibility with the cellulose resin.

Examples of the alicyclic monocarboxylic acid include cyclopentanecarboxylic acid, cyclohexanecarboxylic acid, cyclooctanecarboxylic acid, and derivatives thereof, and these may be used alone or in combination of two or more.

As the aromatic monocarboxylic acid, there may be mentioned: benzoic acid, dimethyl benzoic acid, trimethyl benzoic acid, tetramethyl benzoic acid, ethyl benzoic acid, propyl benzoic acid, butyl benzoic acid, cuminic acid, p-tert-butyl benzoic acid, o-methyl benzoic acid, m-methyl benzoic acid, p-toluic acid, ethoxy benzoic acid, propoxy benzoic acid, naphthoic acid, nicotinic acid, furoic acid, anisic acid, and the like, in which an alkyl group is introduced into a benzene ring of benzoic acid; monohydroxybenzoic acids such as 2-hydroxybenzoic acid (salicylic acid), 3-hydroxybenzoic acid, 4-hydroxybenzoic acid (p-hydroxybenzoic acid), and 3, 5-di-tert-butyl-4-hydroxybenzoic acid; dihydroxybenzoic acids such as 2, 3-dihydroxybenzoic acid (2-pyrocatechoic acid), 2, 4-dihydroxybenzoic acid (β -resorcyclic acid), 2, 5-dihydroxybenzoic acid (gentisic acid), 2, 6-dihydroxybenzoic acid (γ -resorcyclic acid), 3, 4-dihydroxybenzoic acid (protocatechuic acid), and 3, 5-dihydroxybenzoic acid (α -resorcyclic acid); trihydroxybenzoic acids such as 3, 4, 5-trihydroxybenzoic acid and 2, 4, 6-trihydroxybenzoic acid; a substance having a hydroxyl group introduced into the benzene ring of a benzoic acid such as monohydroxynaphthoic acid, for example, 2-hydroxy-1-naphthoic acid, 1-hydroxy-2-naphthoic acid, 3-hydroxy-2-naphthoic acid, or 6-hydroxy-2-naphthoic acid; aromatic monocarboxylic acids having two or more benzene rings such as diphenic acid, naphthoic acid, and tetrahydronaphthoic acid; or derivatives thereof may be used alone or in combination of two or more. Among them, benzoic acid and p-toluic acid are preferable from the viewpoint of excellent compatibility with the cellulose resin.

The monocarboxylic acid is not particularly limited in the number of carbon atoms other than the carbon atom of the carboxyl group, but is preferably 1 to 12, more preferably 1 to 8.

(monohydric alcohol)

Examples of the monohydric alcohol used in the present embodiment include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, isopentanol, tert-pentanol, cyclopentanol, 1-hexanol, cyclohexanol, 1-heptanol, 1-octanol, 2-ethyl-1-hexanol, isononyl alcohol, 1-nonanol, pentanol, decanol, lauryl alcohol, methyl lactate, and ethyl lactate, and two or more of these alcohols may be used alone or in combination. Among them, 1-butanol, cyclohexanol, 2-ethyl-1-hexanol, and isononyl alcohol are preferable from the viewpoint of easy availability and synthesis of raw materials.

The monohydric alcohol is not particularly limited in the number of carbon atoms, but is preferably 1 to 18, more preferably 2 to 12, and still more preferably 4 to 10.

[ ester Compound ]

In one embodiment of the present invention, the polyester-based additive further comprises an ester compound having a polybasic acid and a monohydric alcohol, or a polyhydric alcohol and a monocarboxylic acid as essential raw materials. The ester compound of the present embodiment may be a diester using a dibasic acid and a monohydric alcohol as essential raw materials, or a diester using a monocarboxylic acid and a dihydric alcohol as essential raw materials. The polybasic acids, polyhydric alcohols, monocarboxylic acids, and monohydric alcohols are the same as those in the polyester, and therefore, the description thereof is omitted.

(dibasic acid)

As the dibasic acid used in one embodiment of the present invention, an aliphatic dicarboxylic acid or an aromatic dicarboxylic acid can be used.

Examples of the aliphatic dicarboxylic acid include malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedicarboxylic acid, cyclohexanedicarboxylic acid, dimer acid, fumaric acid, and derivatives thereof.

Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, terephthalic acid, 1, 4-naphthalenedicarboxylic acid, 1, 5-naphthalenedicarboxylic acid, 1, 8-naphthalenedicarboxylic acid, 2, 3-naphthalenedicarboxylic acid, 2, 6-naphthalenedicarboxylic acid, 2, 7-naphthalenedicarboxylic acid, 4' -biphenyldicarboxylic acid, and derivatives thereof.

The number of carbon atoms of the dibasic acid other than the carboxyl group is not particularly limited, but is preferably 1 to 12, more preferably 2 to 8.

(dihydric alcohol)

Examples of the diol used in one embodiment of the present invention include ethylene glycol, 1, 2-propanediol, 1, 3-propanediol, 2-methylpropanediol, 1, 2-butanediol, 1, 3-butanediol, 1, 4-butanediol, 2, 3-butanediol, 1, 5-pentanediol, 3-methyl-1, 5-pentanediol, neopentyl glycol, 1, 2-cyclopentanediol, 1, 3-cyclopentanediol, 1, 6-hexanediol, 1, 7-heptanediol, 1, 8-octanediol, 1, 9-nonanediol, 1, 10-decanediol, hydrogenated bisphenol a, a diol, bisphenol a, an ethylene oxide adduct of bisphenol a, and a propylene oxide adduct of bisphenol a.

The number of carbon atoms of the diol is not particularly limited, but is preferably 2 to 12, more preferably 2 to 8, and still more preferably 2 to 4.

The content of the ester compound in the polyester-based additive is preferably 50% by mass or less, more preferably 40% by mass or less, and further preferably 30% by mass or less of the polyester-based additive.

[ esterification reaction ]

In one embodiment of the present invention, the polyester-based additive or ester compound can be produced by subjecting a raw material to an esterification reaction at a temperature of, for example, 180 to 250 ℃ for 10 to 25 hours in the presence of an esterification catalyst, if necessary. Conditions such as the temperature and time of the esterification reaction are not particularly limited and may be appropriately set. The monocarboxylic acid and the dicarboxylic acid may be used as the raw materials, and an acid itself, an ester compound thereof, an acid chloride thereof, an acid anhydride of a dicarboxylic acid, or the like may be used as the raw materials.

Examples of the esterification catalyst include titanium catalysts such as tetraisopropyl titanate and tetrabutyl titanate, tin catalysts such as dibutyltin oxide, and organosulfonic acid catalysts such as p-toluenesulfonic acid.

The amount of the esterification catalyst to be used may be appropriately set, but is usually preferably in the range of 0.001 to 0.1 part by mass based on 100 parts by mass of the total amount of the raw materials.

[ cellulose ester resin composition ]

The cellulose ester resin composition of the present invention comprises an additive for cellulose ester resins and a cellulose ester resin.

[ cellulose ester resin ]

Examples of the cellulose ester resin include those obtained by esterifying a part or all of the hydroxyl groups of cellulose obtained from cotton linter, wood pulp, kenaf, and the like.

Specific examples of the cellulose ester resin include cellulose acetate such as triacetyl cellulose and diacetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate propionate butyrate, cellulose acetate phthalate, and cellulose nitrate. These cellulose ester resins may be used alone or in combination of two or more. When a film comprising the cellulose ester resin composition of the present invention is used as an optical film, particularly a polarizer protective film, it is preferable to use cellulose acetate because a film having excellent mechanical properties and transparency can be obtained.

The cellulose acetate is preferably used because an optical film made of the obtained cellulose ester resin composition is excellent in mechanical properties and transparency when the average degree of acetylation (amount of bound acetic acid) is in the range of 50.0 to 62.5% by mass.

In addition, in order to improve the moisture permeability resistance of the optical film, the average acetylation degree of the cellulose acetate is preferably in the range of 54 to 62.5 mass%. By using triacetyl cellulose having a higher average acetylation degree, a cellulose ester resin film having excellent moisture permeation resistance can be obtained. In order to adjust the optical film to a high retardation value, the average degree of acetylation of the cellulose acetate is preferably in the range of 50.0 to 58 mass%.

The average acetylation degree is a mass ratio of acetic acid generated by alkalizing cellulose acetate based on the mass of the cellulose acetate.

The cellulose ester resin having a number average molecular weight of 70000 to 300000 is preferable because mechanical properties of the film can be improved. When higher mechanical properties are required, it is more preferable to use a cellulose ester resin in the range of 80000 to 200000.

The content of the metal compound in the cellulose ester resin composition of the present invention is preferably 10 to 3000ppm, more preferably 50 to 2000ppm, and further preferably 200 to 1000ppm, based on 100 parts by mass of the cellulose ester resin.

The metal content is preferably 0.1 to 1000ppm, more preferably 1 to 500ppm, and still more preferably 10 to 100 ppm. The metal content as referred to herein does not include the metal content originally contained in the cellulose ester resin.

The content of the polyester-based additive in the cellulose ester resin composition of the present embodiment is preferably 0.1 to 50 parts by mass, more preferably 1 to 30 parts by mass, and still more preferably 3 to 20 parts by mass, based on 100 parts by mass of the cellulose ester resin.

The cellulose ester resin composition of the present embodiment contains the metal compound of the present invention, a polyester-based additive, and a resin for optical materials such as cellulose ester resin, and may contain other various additives as needed.

Examples of the additives include the metal compound of the present invention, modifiers other than polyester additives, thermoplastic resins, ultraviolet absorbers, delustering agents, stabilizers, deterioration inhibitors (for example, antioxidants, peroxide decomposers, radical inhibitors, metal deactivators, acid scavengers), dyes, and the like.

The other modifiers may be polyester compounds, ester resins other than diester compounds, phosphate esters such as triphenyl phosphate (TPP), tricresyl phosphate and cresyldiphenyl phosphate, phthalate esters such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate and di-2-ethylhexyl phthalate, ethyl phthalate ethyl glycolate, butyl phthalate butyl glycolate, trimethylolpropane tribenzoate, pentaerythritol tetraacetate, acetyl tributyl citrate, and the like, which are specified in the present invention, within a range not to impair the effects of the present invention.

The thermoplastic resin is not particularly limited, but examples thereof include polyester resins, polyether ester resins, polyurethane resins, acrylic resins, epoxy resins, and toluene sulfonamide resins other than the ester resin of the present invention.

The ultraviolet absorber is not particularly limited, but examples thereof include hydroxybenzophenone compounds, benzotriazole compounds, salicylate compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex salt compounds, and the like. Preferably, the ultraviolet absorber is used in the range of 0.01 to 2 parts by mass per 100 parts by mass of the cellulose ester resin.

Examples of the matting agent include silica, titanium oxide, alumina, calcium carbonate, calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, kaolin, talc, and the like. Preferably, the matting agent is used in an amount of 0.1 to 0.3 parts by mass based on 100 parts by mass of the cellulose ester resin.

The type and amount of the dye are not particularly limited as long as the dye does not interfere with the object of the present invention.

[ molded article of cellulose ester resin composition ]

The cellulose ester resin composition of the present invention can be molded to obtain a molded article. The cellulose ester resin composition of the present invention is excellent in transparency of molded articles, and therefore can be used as an optical film.

[ optical film ]

The optical film of the present invention is a film obtained by molding the cellulose ester resin composition of the present invention. The thickness of the optical film of the present invention varies depending on the application, but is preferably in the range of 10 to 300 μm.

The optical film of the present invention may have properties such as optical anisotropy or optical isotropy, but when the optical film is used as a protective film for a polarizer, an optically isotropic film that does not block the transmission of light is preferably used.

The optical film of the present invention can be used for various purposes. The most effective application is, for example, a protective film for a polarizer, which requires optical isotropy, of a liquid crystal display, but it can also be used as a support for a protective film for a polarizer, which requires an optical compensation function.

The optical film of the present invention can be used for liquid crystal cells of various display modes. Examples thereof include IPS (In-Plane Switching), TN (Twisted Nematic), VA (Vertically Aligned), and OCB (Optically compensated Bend).

In addition, the film can be used as a film for protecting a polarizing film in sunglasses and goggles for preventing ultraviolet rays and glare.

[ method for producing optical film ]

The optical film of the present invention can be produced, for example, by a melt extrusion method. Specifically, the cellulose ester resin composition containing the cellulose ester resin, the modifier for cellulose ester resin, and other various additives, if necessary, can be obtained by melt-kneading the cellulose ester resin composition with an extruder or the like, and molding the composition into a film with a T-die or the like.

Further, the optical film of the present invention can be obtained by molding, for example, a so-called solution casting method (solvent casting method) as follows, in addition to the above molding method: the cellulose ester resin and the modifier for cellulose ester resin are dissolved in an organic solvent to obtain a resin solution, the resin solution is cast on a metal support, and the organic solvent is distilled off and dried.

According to the solution casting method, a film having excellent surface smoothness and being less likely to have irregularities on the surface can be obtained. Therefore, the film obtained by the solution casting method can be preferably used for optical applications, and can be preferably used as a protective film for a polarizer, a phase difference film, a reflective plate, a viewing angle improving film, an antiglare film, a non-reflective film, an antistatic film, a member of a liquid crystal display such as a color filter, or a polarizing film protective film in an antiglare article such as a polarizing sunglass.

Examples

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

[ Synthesis of polyester-based additive ]

Synthetic example 1: polyester-based additive 1

107.6g of propylene glycol (hereinafter abbreviated as "PG") as a diol component, 361.6g of phthalic anhydride (hereinafter abbreviated as "PA") as a dicarboxylic acid component, 412.2g of isononyl alcohol (hereinafter abbreviated as "INA") as an alcohol component, and 0.06g of tetraisopropyl titanate (TIPT) as an esterification catalyst were put into a four-necked flask having an internal volume of 2 liters equipped with a thermometer, a stirrer, and a reflux condenser, and the temperature was raised to 220 ℃ in stages while stirring under a nitrogen stream, and then the reaction was continued at 230 ℃ to carry out a dehydration condensation reaction for a total of 19 hours, thereby obtaining a polyester-based additive 1 (acid value 0.4, number average molecular weight 560).

[ Synthesis example 2: polyester-series additive 2

PG 405g as a diol component, Adipic Acid (AA)79g as a dicarboxylic acid, PA 240g, benzoic acid (BzA)586g as a monocarboxylic acid, and TIPT 0.08g as an esterification catalyst were put into a 2-liter four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser, and the internal volume thereof was increased to 230 ℃ stepwise while stirring under a nitrogen stream, and then the reaction was continued at 230 ℃ for a total of 19 hours to carry out a dehydration condensation reaction, thereby obtaining a polyester-based additive 2 (acid value 0.2, number-average molecular weight 410).

[ Synthesis example 3: polyester-based additive 3

In a 2 liter four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, 401g of PG as a diol component, 327g of AA as a dicarboxylic acid, BzA 545g as a monocarboxylic acid and 0.08g of TIPT as an esterification catalyst were charged, the temperature was gradually raised to 230 ℃ while stirring under a nitrogen stream, and the reaction was continued at 230 ℃ for a total of 19 hours to carry out a dehydration condensation reaction, thereby obtaining a polyester-based additive 3 (acid value 0.4 and number average molecular weight 400).

[ Synthesis example 4: polyester-based additive 4

448g of ethylene glycol (hereinafter abbreviated as EG) as a diol component, 812g of AA as a dicarboxylic acid, and 0.04g of TIPT as an esterification catalyst were put into a 2-liter four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser, and the internal volume was increased to 225 ℃ in stages while stirring under a nitrogen stream, and then the reaction was continued at 225 ℃ to carry out a dehydration condensation reaction for a total of 19 hours, thereby obtaining a polyester-based additive 4 (acid value 0.2, number average molecular weight 1350).

[ Synthesis example 5: polyester 5)

PG 383g as a diol component, AA 381g as a dicarboxylic acid, PA 129g as a dicarboxylic acid and TIPT 0.05g as an esterification catalyst were charged into a 2-liter four-necked flask equipped with a thermometer, a stirrer and a reflux condenser, and the internal volume was gradually increased to 210 ℃ while stirring under a nitrogen stream, and then the reaction was continued at 210 ℃ to carry out a dehydration condensation reaction for a total of 19 hours, thereby obtaining polyester 5 (acid value 0.4, number average molecular weight 760).

[ Synthesis example 6: ester Compound 1

PG 648g as a diol component, dipropylene glycol 109g, benzoic acid 1980g as a monocarboxylic acid component, and tetraisopropyl titanate 0.2g were charged into a 3-liter four-necked flask equipped with a thermometer, a stirrer, and a reflux condenser, and the internal volume was increased to 240 ℃ over 8 hours. Then, the reaction was carried out at 240 ℃ for 10 hours. After the reaction, unreacted raw materials were removed under reduced pressure at 190 ℃ to obtain ester compound 1 (acid value 0.1, number average molecular weight 290) as a liquid diester at room temperature.

[ polyester-based additive 5]

The polyester additive 5 is obtained by blending the polyester 5 and the ester compound 1 at a weight ratio of 7/3.

[ preparation of optical film ]

Optical films were produced using the polyester additives 1 to 5, and the commercially available cellulose ester resins and metal compounds described below.

[ cellulose ester resin ]

Triacetyl cellulose (acetylation degree 60.7%)

Diacetylcellulose (acetylation degree 55.5%)

[ Metal Compound ]

Calcium hydroxide (Heguang pure drug Co., Ltd.)

Lithium stearate (Li-St, manufactured by Ridong Kasei Kogyo Co., Ltd.)

Sodium stearate (Na-St, manufactured by Ridonghua chemical industry Co., Ltd.)

Aluminum stearate (Al-St, manufactured by Ridonghua chemical industry Co., Ltd.)

Calcium stearate (Ca-St, manufactured by Ridonghua chemical industry Co., Ltd.)

Zinc stearate (Zn-St, manufactured by Ridonghua chemical industry Co., Ltd.)

Barium stearate (Ba-St, manufactured by Ridong Kasei Kogyo Co., Ltd.)

2-Ethyl hexanoic acid calcium (DIC-OCTOATE, available from DIC corporation)

2-Ethylhexanoic acid/calcium neodecanoate (DICNATE, manufactured by DIC corporation)

Calcium laurate (CS-3, manufactured by Ridonghua chemical industry Co., Ltd.)

Calcium montanate (CS-8CP, manufactured by Ridonghua chemical industry Co., Ltd.)

12-Hydroxystearic acid calcium salt (CS-6, manufactured by Ridonghua chemical Industrial Co., Ltd.)

Examples 1 to 18 and 20

100 parts of triacetyl cellulose (TAC) resin, 10 parts of a polyester additive and 20 to 1000ppm of a metal compound were added to a mixed solvent composed of 810 parts of methylene chloride and 90 parts of methanol and dissolved to prepare a coating solution. The coating solution was cast on a glass plate to a thickness of 0.8mm, dried at room temperature for 16 hours, then dried at 50 ℃ for 30 minutes, and further dried at 120 ℃ for 30 minutes to obtain a cellulose ester film. The following items concerning the storage stability of the obtained film were evaluated. The results are shown in Table 1.

[ example 19]

A cellulose ester film was obtained in the same manner as in example 16, except that a Diacetylcellulose (DAC) resin was used instead of the triacetylcellulose resin. The following items concerning the storage stability of the obtained film were evaluated. The results are shown in Table 1.

Comparative example 1

100 parts of triacetyl cellulose (TAC) resin was added to and dissolved in a mixed solvent composed of 810 parts of methylene chloride and 90 parts of methanol to prepare a dope. The coating solution was cast on a glass plate to a thickness of 0.8mm, dried at room temperature for 16 hours, then dried at 50 ℃ for 30 minutes, and further dried at 120 ℃ for 30 minutes to obtain a cellulose ester film. The following items concerning the storage stability of the obtained film were evaluated. The results are shown in Table 1.

[ comparative examples 2 to 4]

A coating solution was prepared by dissolving 100 parts of Triacetylcellulose (TAC) resin, 10 parts of a polyester additive or triphenyl phosphate (TPP) in a mixed solvent composed of 810 parts of methylene chloride and 90 parts of methanol. The coating solution was cast on a glass plate to a thickness of 0.8mm, dried at room temperature for 16 hours, then dried at 50 ℃ for 30 minutes, and further dried at 120 ℃ for 30 minutes to obtain a cellulose ester film. The following items concerning the storage stability of the obtained film were evaluated. The results are shown in Table 1.

Comparative example 5

A coating solution was prepared by dissolving 100 parts of Triacetylcellulose (TAC) resin, 10 parts of TPP, and 500ppm of a metal compound in a mixed solvent composed of 810 parts of methylene chloride and 90 parts of methanol. The coating solution was cast on a glass plate to a thickness of 0.8mm, dried at room temperature for 16 hours, then dried at 50 ℃ for 30 minutes, and further dried at 120 ℃ for 30 minutes to obtain a cellulose ester film. The following items concerning the storage stability of the obtained film were evaluated. The results are shown in Table 1.

[ evaluation of storage stability ]

[ amount of acetic acid produced ]

1.2g of the obtained film was put into a 25ml sample bottle, and the amount of acetic acid generated in 336 hours under conditions of 85 ℃ C.. times.humidity 90% was examined using a detector tube (for acetic acid in a Hechuan gas detector tube).

The very good was indicated when the amount of acetic acid generated was 25ppm or less, the very good was indicated when the amount was 50ppm or less, and the very good was indicated when the amount was more.

[ transparency ]

The transparency of the film was judged by measuring the HAZE value. The HAZE value was measured in accordance with JIS K7105 using a HAZE meter ("NDH 5000" manufactured by Nippon Denshoku industries Co., Ltd.). The closer the value obtained is to 0%, the more transparent it is.

[ Table 1]

As shown in table 1, when the metal compound was used in combination with the polyester-based additive, the amount of acetic acid generated was small, and excellent hydrolysis resistance was exhibited. The stabilizing effect was not confirmed in the case of the polyester-based additive alone or in the case of the combination of TPP and a metal compound.