TWI761527B - Ester resin, antiplasticizer, cellulose ester resin composition, optical film and liquid crystal display device - Google Patents

Abstract

The present invention provides an ester resin which is excellent in the balance of strength, moisture permeability resistance, and optical properties, and can be suitably used as an antiplasticizer for optical resins, especially when processed into a film, and a resin composition containing the same. A product, an optical film obtained using the resin composition, and a liquid crystal display device using the same. Specifically, an ester resin, which is characterized by being represented by B-(GA) _n -GB [wherein, B is a monocarboxylic acid residue, G is an alkanediol residue, an oxyalkanediol residue or an aromatic Diol residues, A is a dicarboxylic acid residue, more than 20 mol% of the total molar number of A is an isophthalic acid residue, n is the number of repetitions, and in each repetition, G and A can be the same or may be different, and a plurality of B and G may be the same or different. ]; The cellulose ester resin composition comprising the composition, the optical film and the liquid crystal display device comprising the composition.

Description

Ester resin, antiplasticizer, cellulose ester resin composition, optical film and liquid crystal display device

The present invention relates to an ester resin suitable as an antiplasticizer for resins for optical materials, a cellulose ester resin containing the same, an optical film obtained using the resin composition, and a liquid crystal display device using the same.

In recent years, the liquid crystal display system has been thinned, and the polarizer protective film has also been thinned from the conventional 80 μm to 60 μm to 25 μm. For the protective film of the polarizing plate, from the viewpoint of easy bonding with the polarizing plate, a triacetyl cellulose resin (hereinafter referred to as TAC) has been used in many cases.

However, since TAC is hard and brittle, when it becomes a film, its strength is insufficient, and there is a problem that breakage is easily caused. In addition, TAC has high moisture permeability and is likely to cause dimensional changes due to moisture absorption. Therefore, it is necessary to suppress moisture absorption with additives, and various additives have been provided (for example, refer to Patent Document 1).

Usually, if an additive is added to suppress moisture permeation, plasticization of the resin occurs at the same time, so it is difficult to achieve both the strength and moisture permeation resistance of the obtained film. Therefore, it is necessary to develop an additive (=antiplasticizer) that can suppress the moisture permeation and improve the modulus of elasticity at the same time.

[Prior Art Literature] [Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. 2013-151699

In view of the above-mentioned circumstances, the problem to be solved by the present invention is to provide an excellent balance of strength, moisture permeability resistance, and optical properties especially when processed into a film form, and which can be suitably used as an anti-plasticizer for optical resins An ester resin, a resin composition comprising the same, an optical film obtained using the resin composition, and a liquid crystal display device using the same.

As a result of careful examination, the inventors of the present invention found that the above-mentioned problems can be solved by adjusting the raw materials in the ester resin, in particular, adjusting the use ratio of the dicarboxylic acid, and the present invention has been completed.

That is, the present invention provides an ester resin characterized by the following general formula (1); a resin composition comprising the same, an optical film obtained by using the composition, and a liquid crystal display device using the optical film .

B-(GA) _n -GB (1)

[In formula (1), B is a monocarboxylic acid residue, G is an alkanediol residue, an oxyalkanediol residue or an aryldiol residue, A is a dicarboxylic acid residue, and the sum of A is a More than 20 mol% of the ear number are isophthalic acid residues, n is the number of repetitions, and in each repetition, G and A may be the same or different, and a plurality of B and G may be the same or different. ]

According to the present invention, it is possible to provide an ester resin which is excellent in the balance of strength, moisture permeation resistance, and optical properties especially when processed into a film form, and which can be suitably used as an antiplasticizer for optical resins. In addition, by using the specific ester resin, especially in the optical film containing the cellulose ester resin, the improvement of the elastic coefficient, the suppression of moisture permeability, and the maintenance of the optical properties can be combined, and it can be used as a liquid crystal display device. suitable for use with optical films.

[Form of implementing the invention]

The ester resin of the present invention is characterized by being represented by the following general formula (1).

B-(GA) _n -GB (1)

[In formula (1), B is a monocarboxylic acid residue, G is an alkanediol residue, an oxyalkanediol residue or an aryldiol residue, A is a dicarboxylic acid residue, and the sum of A is a More than 20 mol% of the ear number are isophthalic acid residues, n is the number of repetitions, and in each repetition, G and A may be the same or different, and a plurality of B and G may be the same or different. ]

B in the aforementioned general formula (1) is a monocarboxylic acid residue, and specific examples thereof include an aryl monocarboxylic acid residue or an aliphatic monocarboxylic acid residue. Here, the "carboxylic acid residue" means a group other than -OH in the carboxyl group. From the viewpoints of easiness of obtaining raw materials, easiness of esterification reaction, and easiness of obtaining a balance between moisture permeability resistance, elastic modulus, and optical properties when mixed with a cellulose ester resin described later, the above-mentioned aryl monomer The carboxylic acid residue is preferably an arylmonocarboxylic acid residue having 6 to 12 carbon atoms, and examples thereof include benzoic acid, dimethylbenzoic acid, trimethylbenzoic acid, tetramethylbenzoic acid, Ethyl benzoic acid, propyl benzoic acid, butyl benzoic acid, p-isopropyl benzoic acid, p-tertiary butyl benzoic acid, o-toluic acid, m-toluic acid, p-toluic acid, ethoxybenzoic acid, propoxy Benzoic acid, anisic acid, naphthoic acid, etc. may be used alone or in combination of two or more. In particular, the residues of benzoic acid, p-toluic acid, and dimethylbenzoic acid are preferable, and the residues of benzoic acid are more preferable from the viewpoint of more easily exhibiting the effects of the present invention. In addition, the number of carbon atoms here is regarded as not including the carbon atom in the carboxyl group. Moreover, it may be a residue of aromatic nicotinic acid, furoic acid, etc. which may have a substituent.

From the viewpoints of easiness of obtaining raw materials, easiness of esterification reaction, and easiness of obtaining a balance between moisture permeability resistance, elastic modulus, and optical properties when mixing with cellulose ester resins described later The carboxylic acid residue is preferably an aliphatic monocarboxylic acid residue having 1 to 8 carbon atoms, for example, residues of acetic acid, propionic acid, butyric acid, caproic acid, octanoic acid, octanoic acid, etc. can be used alone. When used, two or more kinds can be combined, and acetic acid is particularly preferred. In addition, the number of carbon atoms here is regarded as not including the carbon atom in the carboxyl group.

G in the aforementioned general formula (1) is an alkanediol residue, an oxyalkanediol residue or an aryldiol residue. The diol residue represents a group obtained by removing a hydrogen atom from a hydroxyl group.

The aforementioned alkanediol residue is preferably an alkanediol residue having 2 to 12 carbon atoms, from the viewpoint that the effects of the present invention are more easily exhibited, and examples thereof include ethylene glycol, 1, 2 -Propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol Alcohol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2- n-Butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2, 2,4-Trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1 Residues such as ,10-decanediol and 1,12-dodecanediol may be used alone or in combination of two or more. From the viewpoint of being an ester resin having more excellent compatibility when mixed with a cellulose ester resin described later, among these, it is preferable that the number of carbon atoms not including a branch between OH groups is 3 or less, and among them, The residues of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, and 2-methyl-1,3-propanediol are preferred, and ethylene glycol, 1,3-propanediol are more preferred. Residue of 2-propanediol.

The aforementioned oxyalkanediol residue is preferably an oxyalkanediol residue having 4 to 12 carbon atoms from the viewpoint of more easily exhibiting the effects of the present invention, and, for example, diethylenediol Residues such as alcohol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol may be used alone or in combination of two or more.

From the viewpoint that the effects of the present invention are more easily exhibited, the aryl diol residue is preferably an aryl diol residue having 6 to 18 carbon atoms, and examples thereof include hydroquinone, isophthalic diol Residues of phenol, bisphenol A, alkylene oxide adduct of bisphenol A, bisphenol F, alkylene oxide adduct of bisphenol F, bisphenol, alkylene oxide adduct of bisphenol, etc., can be It can be used alone or in combination of two or more.

In addition, A in the aforementioned general formula (1) is a dicarboxylic acid residue, specifically, an alkylene dicarboxylic acid residue (A1) or an aryl dicarboxylic acid residue (A2), and A The molar number of isophthalic acid residues in the total molar number must be 20 mol% or more. Here, the dicarboxylic acid residue refers to a group excluding -OH in the carboxyl group.

In the ester resin represented by the aforementioned general formula (1), when a dicarboxylic acid using a large amount of isophthalic acid as a raw material is mixed with an optical resin to be described later, the optical resin, in particular, Cellulose ester resin, when processed into a film form without plasticization, improves the elastic modulus and imparts moisture permeability resistance without impairing the original optical properties of the optical resin, and can be appropriately used for the development of film formation optical film applications.

From the viewpoint of exerting the aforementioned effects, the molar number of isophthalic acid residues in the dicarboxylic acid residues must be 20 mol % or more, and in particular, from the viewpoint of exerting the above-mentioned effects, isophthalic acid The content of residues is preferably in the range of 25 to 100 mol %.

The alkylene dicarboxylic acid residue (A1) that can be combined with the isophthalic acid residue is preferably an alkylene having 2 to 12 carbon atoms, from the viewpoint that the effects of the present invention are more easily exhibited. dicarboxylic acid residues, for example, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, maleic acid, fumaric acid, 1,2-dicarboxycyclohexane, 1,2-dicarboxycyclohexane, Residues such as 2-dicarboxycyclohexene may be used alone or in combination of two or more. Among these, the residues of succinic acid, adipic acid, and 1,2-dicarboxycyclohexane are preferred, and the most preferred are adipic acid, from the viewpoint of obtaining an optical film having better moisture permeability resistance. Residues.

As the aforementioned aryl dicarboxylic acid residue (A2) which can be combined with an isophthalic acid residue, for example, phthalic acid, terephthalic acid, 1,4-naphthalenedicarboxylic acid, 2, Residues such as 3-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid, and 1,8-naphthalenedicarboxylic acid may be used alone or in combination of two or more. Among these, the residues of phthalic acid and terephthalic acid are preferable, and the residues of phthalic acid are most preferable from the viewpoint of obtaining an optical film with higher strength.

As far as the present invention is concerned, it is the ester resin represented by the aforementioned general formula (1), or it may be a mixture of compounds whose B, G, and A are the same, only n, that is, only the number of repetitions is different, or, It may be a mixture of compounds in which B, G, A and n in the general formula (1) are different from each other. In the present invention, in order to make the optical film obtained by mixing with the resin for optical materials described later (especially with cellulose ester resin) to have both moisture permeability resistance and improvement of the elastic coefficient, it is more preferable to follow the general formula (1). ) in the GPC measurement of the ester resin shown in the area ratio, the n=0 component in the aforementioned general formula (1) is 10 to 50%, and n is the area % of the component of 3 or more and the n=0 component. The ratio of area % (n≧3)/(n=0) is 3 or less.

By setting the n=0 component as described above, that is, by setting the diester compound to a specific content rate, it can be appropriately placed in the resin for optical materials, especially in the gap of the cellulose ester resin, as a result. , exhibits the effect of suppressing moisture permeability, and at the same time, by relatively reducing the content of components whose n is 3 or more, the compatibility with the resin for optical materials can be ensured, and the transparency that can be used as an optical film can be maintained more effectively. sex.

From the viewpoints of further exhibiting these effects, suppressing contamination of the production line due to volatilization, or maintaining the transparency of the optical film, etc., it is preferable to use the area ratio in the GPC measurement. The n=0 component in the formula (1) is 20 to 50%, and it is preferably the ratio of the area % of the component where n is 3 or more to the area % of the n=0 component (n≧3)/(n=0 ) is in the range of 0.2 to 1.5.

In addition, the GPC measurement in the present invention was carried out under the following conditions.

[GPC measurement conditions]

Measuring device: High-speed GPC device "HLC-8320GPC" manufactured by Tosoh Co., Ltd.

Column: "TSK GURDCOLUMN SuperHZ-L" made by Tosoh Co., Ltd. + "TSK gel SuperHZM-M" made by Tosoh Co., Ltd. + "TSK gel SuperHZM-M" made by Tosoh Co., Ltd. + "TSK gel made by Tosoh Co., Ltd." SuperHZ-2000" + "TSK gel SuperHZ-2000" manufactured by Tosoh Co., Ltd.

Detector: RI (differential refractometer)

Data processing: "EcoSEC Data Analysis Version 1.07" manufactured by Tosoh Co., Ltd.

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 solution obtained by filtration with a microfilter was used as a measurement sample.

Sample injection volume: 20μl

Standard sample: According to the aforementioned "HLC-8320GPC" measurement manual, the following monodisperse polystyrene having a known molecular weight was used.

(monodisperse polystyrene)

"A-300" manufactured by Tosoh Co., Ltd.

"A-500" manufactured by Tosoh Co., Ltd.

"A-1000" manufactured by Tosoh Co., Ltd.

"A-2500" manufactured by Tosoh Co., Ltd.

"A-5000" manufactured by Tosoh Co., Ltd.

"F-1" manufactured by Tosoh Co., Ltd.

"F-2" manufactured by Tosoh Co., Ltd.

"F-4" manufactured by Tosoh Co., Ltd.

"F-10" manufactured by Tosoh Co., Ltd.

"F-20" manufactured by Tosoh Co., Ltd.

"F-40" manufactured by Tosoh Co., Ltd.

"F-80" manufactured by Tosoh Co., Ltd.

"F-128" manufactured by Tosoh Co., Ltd.

"F-288" manufactured by Tosoh Co., Ltd.

(GPC analysis conditions)

In the ester resin of the present invention, the area % of the component n=0 and the component in which n is 3 or more can be calculated as follows. GPC measurement of the ester resin was performed to obtain the polystyrene-equivalent molecular weight of each component corresponding to the detected peak, and the content ratio (area fraction) of each component corresponding to the detected peak was calculated from the ratio of the detected peak areas.

From the viewpoint of further exhibiting the effects of the present invention, in the general formula (1), it is preferable that B is a residue of benzoic acid or acetic acid, and G is ethylene glycol, 1,2-propanediol, 1,3- Residues of propylene glycol, 1,2-butanediol, 2-methyl-1,3-propanediol, and A1 of the group can be the residues of succinic acid, adipic acid, 1,2-dicarboxycyclohexane, A2 is the residue of phthalic acid and terephthalic acid, especially B is the residue of benzoic acid, G is the residue of ethylene glycol and 1,2-propanediol, and A1 can be combined with hexanediol Acid residue, A2 is the residue of phthalic acid.

Moreover, the weight average molecular weight of the ester resin of the present invention is preferably in the range of 350 to 1200, particularly preferably in the range of 350 to 800, from the viewpoint of both compatibility and film properties. Also, from the viewpoint of both compatibility and film properties, the average value of the repetition number n in the general formula (1) is preferably in the range of 0.2 to 3. In addition, the weight average molecular weight and the average value of n are also the values measured by the aforementioned GPC measurement.

Furthermore, from the viewpoint of more favorable compatibility with the resin for optical materials, the acid value of the ester resin of the present invention is preferably 5 or less, more preferably 1 or less. Moreover, from the same viewpoint, the hydroxyl value of the ester resin is preferably 50 or less, more preferably 20 or less.

The ester resin of the present invention can be produced, for example, by esterifying the above-mentioned raw materials in the presence of an esterification catalyst, for example, in a temperature range of 180 to 250° C. for 10 to 25 hours. In addition, conditions, such as temperature and time of an esterification reaction, are not specifically limited, It can set suitably. As a monocarboxylic acid or a dicarboxylic acid, an acid itself may be used as a raw material, or its ester product, an acyl chloride, a dicarboxylic anhydride, etc. may be used as a raw material.

Examples of the esterification catalyst include titanium-based catalysts such as tetraisopropyl titanate and tetrabutyl titanate; tin-based catalysts such as dibutyltin oxide; and organic sulfonic acids such as p-toluenesulfonic acid. Department of catalysts, etc.

The usage-amount of the said esterification catalyst should just set suitably, Usually, it is preferable to use it in the range of 0.001-0.1 mass part with respect to 100 mass parts of total amounts of raw materials.

The properties of the ester resin of the present invention mainly vary depending on the weight-average molecular weight, the combination of raw materials, and the like, and are usually liquid, solid, pasty, and the like at room temperature.

As a more specific method of producing an ester resin, a compound having a hydroxyl group at the terminal obtained by using the above-mentioned alkanediols, oxyalkanediols, aryldiols, and dicarboxylic acids can be reacted with monocarboxylic acids. Methods. Here, the aforementioned alkanediols, oxyalkanediols, aryldiols, dicarboxylic acids, and monocarboxylic acids can be added to the reaction system at one time, and these can be reacted. Alternatively, alkanediols can also be used. After the compound having a hydroxyl group at the terminal is obtained from alcohol, oxyalkanediol or aryldiol, and dicarboxylic acid, monocarboxylic acid is added to the reaction system, and the reaction is performed successively.

The ester resin obtained above can also be directly used as the ester resin of the present invention as long as the content of isophthalic acid residues defined in the present invention is 20 mol% or more, or, by the aforementioned GPC measurement, find For the composition of each repetition of n, for example, the content of n=0 components and the content of high molecular weight components can also be adjusted by methods such as distillation method using thin film distillation apparatus, column adsorption method, solvent separation and extraction method, etc. Rate. In particular, it is also possible to use a method in which the content rate of the n=0 component is distilled off by a thin film distillation apparatus until the area ratio measured by GPC is 8% or less, and the diester compound (II) prepared separately is used as n= 0 component is added, and if it satisfies the area ratio in the GPC measurement, the n=0 component in the aforementioned general formula (1) is 10 to 50%, and n is the area % of the component of 3 or more and n=0 component The ratio of area % (n≧3)/(n=0) is 3 or less ester resin. In this case, the raw material used for the ester resin and the raw material of the diester compound prepared separately may be the same or different. In this case, it is necessary to adjust 20 mol% or more of the total molar number of A in the mixed ester resin to be an isophthalic acid residue.

When the aforementioned production method is employed, the diester compound (II) to be added later is preferably represented by the following general formula (2).

B2-G2-B2 (2)

(In the formula, B2 is an aryl monocarboxylic acid residue or aliphatic monocarboxylic acid residue, G2 is an alkanediol residue, an oxyalkanediol residue or an aryldiol residue, and multiple B2 can be the same can be different.)

B2 in the aforementioned general formula (2) is an aryl monocarboxylic acid residue or an aliphatic monocarboxylic acid residue. Here, the "carboxylic acid residue" means a group other than -OH in the carboxyl group. From the viewpoints of easiness of obtaining raw materials, easiness of esterification reaction, and easiness to achieve a balance between moisture permeability resistance and improvement of elastic modulus when mixing with cellulose ester resin described later, as the arylmonocarboxylic acid described above The residue is preferably an arylmonocarboxylic acid residue having 6 to 12 carbon atoms, for example, benzoic acid, dimethylbenzoic acid, trimethylbenzoic acid, tetramethylbenzoic acid, ethyl Benzoic acid, propyl benzoic acid, butyl benzoic acid, p-isopropyl benzoic acid, p-tertiary butyl benzoic acid, o-toluic acid, m-toluic acid, p-toluic acid, ethoxybenzoic acid, propoxybenzoic acid , anisic acid, naphthoic acid, etc., can be used alone or in combination of two or more. In particular, the residues of benzoic acid, p-toluic acid, and dimethylbenzoic acid are preferable, and the residues of benzoic acid are more preferable from the viewpoint of more easily exhibiting the effects of the present invention. In addition, the number of carbon atoms here is regarded as not including the carbon atom in the carboxyl group. Moreover, it may be a residue of aromatic nicotinic acid, furoic acid, etc. which may have a substituent.

The aforementioned aliphatic monocarboxylic acid is used as the aforementioned aliphatic monocarboxylic acid from the viewpoints of easiness in obtaining raw materials, easiness of esterification reaction, and easiness in achieving a balance between moisture permeability resistance and an improvement in elastic modulus when mixed with a cellulose ester resin described later. The residue is preferably a residue of an aliphatic monocarboxylic acid having 1 to 8 carbon atoms, for example, residues of acetic acid, propionic acid, butyric acid, caproic acid, caprylic acid, caprylic acid, etc. can be used alone, Two or more kinds may be combined, and the residues of acetic acid are particularly preferred. In addition, the number of carbon atoms here is regarded as not including the carbon atom in the carboxyl group.

G in the aforementioned general formula (1) is an alkanediol residue, an oxyalkanediol residue or an aryldiol residue. The diol residue represents a group obtained by removing a hydrogen atom from a hydroxyl group.

The aforementioned alkanediol residue is preferably an alkanediol residue having 2 to 12 carbon atoms, from the viewpoint that the effects of the present invention are more easily exhibited, and examples thereof include ethylene glycol, 1, 2 -Propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,4-butanediol, 1,5-pentanediol Alcohol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 2,2-diethyl-1,3-propanediol (3,3-dimethylolpentane), 2- n-Butyl-2-ethyl-1,3-propanediol (3,3-dimethylolheptane), 3-methyl-1,5-pentanediol, 1,6-hexanediol, 2, 2,4-Trimethyl-1,3-pentanediol, 2-ethyl-1,3-hexanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1 Residues such as ,10-decanediol and 1,12-dodecanediol may be used alone or in combination of two or more. Among these, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2-methyl- Residues of 1,3-propanediol, 1,5-pentanediol.

The aforementioned oxyalkanediol residue is preferably an oxyalkanediol residue having 4 to 12 carbon atoms from the viewpoint of more easily exhibiting the effects of the present invention, and, for example, diethylenediol Residues such as alcohol, triethylene glycol, tetraethylene glycol, dipropylene glycol, and tripropylene glycol may be used alone or in combination of two or more.

From the viewpoint that the effects of the present invention are more easily exhibited, the aryl diol residue is preferably an aryl diol residue having 6 to 18 carbon atoms, and examples thereof include hydroquinone, isophthalic diol Residues of phenol, bisphenol A, alkylene oxide adduct of bisphenol A, bisphenol F, alkylene oxide adduct of bisphenol F, bisphenol, alkylene oxide adduct of bisphenol, etc., can be It can be used alone or in combination of two or more.

From the viewpoint of further exhibiting the effects of the present invention, in the general formula (2), B2 is preferably a residue of benzoic acid or acetic acid, and G is 1,2-propanediol, 1,3-propanediol, 1,2-propanediol, and 1,2-propanediol. Residues of 2-butanediol, 1,3-butanediol, 2-methyl-1,3-propanediol, 1,5-pentanediol, diethylene glycol, dipropylene glycol.

The above-mentioned diester compound (II) may be synthesized or commercially available, and at the time of synthesis, it can be produced by the same method as the above-mentioned esterification reaction, and the above-mentioned general formula can be converted by operations such as distillation or column. In (1), the component of n=0 can be obtained by a known method such as a method of isolating the component, and the method is not particularly limited. In addition, in the mixture which may contain subcomponents other than the n=0 component and is uniformly mixed with the ester resin (I), as long as the conditions defined in the present invention can be satisfied, a plurality of different raw materials may be used. as the diester compound (II).

The ester resin of the present invention obtained by the above-mentioned method or the like can be blended into a resin for optical materials, and the obtained film can be excellent in the balance of moisture permeability resistance, elastic modulus, and optical properties, and can be used as The so-called anti-plasticizer can be suitably used especially as an optical film.

The resin for optical materials is not particularly limited as long as it has high transparency and can be processed into a film form, and examples thereof include (meth)acrylic resins, cyclic olefin-based resins, and polycarbonate resins. , cellulose ester resin, etc. In particular, from the viewpoint of further exerting the effects of the present invention, it is preferable to use a cellulose ester resin.

The blending amount of the ester resin of the present invention in the resin for optical materials may be determined according to the properties (moisture permeability resistance, elastic coefficient, etc.) considered to be intended. For example, with respect to 100 parts by mass of the resin for optical materials, it is: The range of 0.1 to 50 parts by mass is preferably the range of 1 to 30 parts by mass, particularly preferably the range of 5 to 20 parts by mass.

As the cellulose ester resin, for example, a part or all of the hydroxyl groups of cellulose obtained from cotton lint, wood pulp, kenaf, etc. can be esterified, etc. Among these, cellulose obtained from cotton lint is used. The film obtained by esterifying the obtained cellulose ester resin is preferable because it can be easily peeled off from the metal support which constitutes the film manufacturing apparatus described later, and the production efficiency of the film can be further improved.

Examples of the cellulose ester resin include cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate phthalate, and cellulose nitrate. etc., since a film excellent in mechanical properties and transparency can be obtained, when used as a protective film for polarizing plates, cellulose acetate is preferably used. These cellulose ester resins may be used alone or in combination of two or more.

The aforementioned cellulose acetate is preferably in the range of the degree of polymerization of 250 to 400, more preferably in the range of 54.0 to 62.5 mass % of the degree of acetylation, and more preferably in the range of 58.0 to 62.5 mass % % range. As long as the degree of polymerization and the degree of acetylation of the aforementioned cellulose acetate are within these ranges, a film having excellent mechanical properties can be obtained. In the present invention, it is more preferable to use so-called cellulose triacetate. In addition, the acetylation degree in this invention is the mass ratio of the acetic acid produced|generated by the saponification of this cellulose acetate with respect to the total amount of cellulose acetate.

The number average molecular weight of the aforementioned cellulose acetate is preferably in the range of 70,000 to 300,000, more preferably in the range of 80,000 to 200,000. When the number average molecular weight of the cellulose acetate is within this range, a film having excellent mechanical properties can be easily obtained.

The optical film in the present invention uses a cellulose ester resin composition containing the ester resin and cellulose ester resin of the present invention, and a resin composition containing other various additives and the like may be used as necessary.

To obtain the optical film of the present invention, methods such as extrusion molding and casting molding are used, for example. Specifically, for example, an unstretched optical film can be extruded using an extruder equipped with a T-die, a circular die, or the like. When the optical film of the present invention is obtained by extrusion molding, as long as a resin composition obtained by melt-kneading the above-mentioned ester resin, cellulose ester resin, other additives, etc. in advance can be used, it can also be melt-kneaded during extrusion molding. and directly extruded.

Examples of the above-mentioned additives include modifiers other than the ester resin of the present invention, thermoplastic resins, ultraviolet absorbers, matting agents, anti-deterioration agents (for example, antioxidants, peroxide decomposers, radical inhibitors) agents, metal inertizers, acid scavengers, etc.), dyes, etc.

As the aforementioned other modifiers, ester resins other than the ester resins defined in the present invention, triphenyl phosphate (TPP), tricresyl phosphate, and toluene diphenyl phosphate can be used within a range that does not impair the effects of the present invention. Phosphate esters such as esters, phthalates such as dimethyl phthalate, diethyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, glycol Ethyl phthalate ethyl alkyd, butyl phthalate butyl glycolate, trimethylolpropane tribenzoate, neopentaerythritol tetraacetate, acetyl tributyl citrate, etc.

Although it does not specifically limit as said thermoplastic resin, For example, the polyester resin other than the ester resin of this invention, a polyester ether resin, a polyurethane resin, an epoxy resin, a tosylate resin, etc. are mentioned.

It does not specifically limit as said ultraviolet absorber, For example, oxybenzophenone type compound, benzotriazole type compound, salicylate type compound, benzophenone compound, cyanoacrylate type compound, Nickel zirconium salt compounds, etc. It is preferable to use the said ultraviolet absorber in the range of 0.01-2 mass parts with respect to 100 mass parts of said cellulose ester resins.

As said matting agent, silicon oxide, titanium oxide, aluminum oxide, calcium carbonate, calcium silicate, aluminum silicate, magnesium silicate, calcium phosphate, kaolin, talc, etc. are mentioned, for example. The aforementioned matting agent is preferably used in the range of 0.1 to 0.3 parts by mass relative to 100 parts by mass of the aforementioned cellulose ester resin.

As the aforementioned dye, the type, the amount of blending, and the like are not particularly limited as long as they are within a range that does not inhibit the purpose of the present invention.

Furthermore, the optical film may be cast on a metal support by casting a resin solution obtained by dissolving the cellulose ester resin composition in an organic solvent, for example, on a metal support, in addition to the above-mentioned molding method, and then, the above-mentioned It is obtained by the so-called solution casting method (solvent casting method) in which the organic solvent is distilled off and dried.

According to the solution casting method, the alignment of the cellulose ester resin in the film in the middle of forming can be suppressed, and thus the obtained film can exhibit substantially optical isotropy. The aforementioned films exhibiting optical isotropy can be used for optical materials such as liquid crystal displays, and among them, are useful for protective films for polarizing plates. In addition, the thin film obtained by the aforementioned method is difficult to form irregularities on the surface thereof, and is also excellent in surface smoothness.

The aforementioned solution casting method generally includes: the first step of dissolving the aforementioned cellulose ester resin composition in an organic solvent and casting the obtained resin solution on a metal support; The contained organic solvent is distilled off and dried to form a second step of a thin film; then, the thin film formed on the metal support is peeled off from the metal support, and the third step of heat-drying is performed.

As the metal support used in the above-mentioned first step, an endless belt-shaped or a drum-shaped metal can be exemplified. For example, a stainless steel and a mirror-finished surface can be used.

When the resin solution is cast on the metal support, it is preferable to use a resin solution filtered with a filter in order to prevent foreign matter from being mixed into the obtained film.

The drying method of the second step is not particularly limited, but for example, by bringing the wind in the temperature range of 30 to 50°C into contact with the top surface and/or bottom surface of the metal support, the above A method of forming a thin film on the aforementioned metal support by evaporating 50 to 80% by mass of the organic solvent contained in the resin solution.

Next, the said 3rd process is a process of peeling the thin film formed in the said 2nd process from a metal support body, and performing heat-drying under a higher temperature condition than the said 2nd process. As the above-mentioned heating drying method, for example, a method of increasing the temperature stepwise under a temperature condition of 100 to 160° C. is preferable because good dimensional stability can be obtained. The organic solvent remaining in the thin film after the second step can be almost completely removed by heating and drying under the aforementioned temperature conditions.

In addition, in the aforementioned first to third steps, the organic solvent may be recovered and reused.

戊烷類。 The organic solvent that can be used when the resin composition is mixed and dissolved in an organic solvent is not particularly limited as long as it can dissolve them. For example, when cellulose acetate is used as the cellulose ester, it is a good As a solvent, for example, an organic halogen compound such as dichloromethane or a dichloromethane is preferably used.

Pentanes.

In addition, on the premise of improving the production efficiency of the film, it is preferable to combine the aforementioned good solvent with a poor solvent such as methanol, ethanol, 2-propanol, n-butanol, cyclohexane, and cyclohexanone.

The mixing ratio of the aforementioned good solvent and poor solvent is preferably in the range of good solvent/poor solvent=75/25~95/5 mass ratio.

The concentration of the cellulose ester resin in the resin solution is preferably 10 to 50% by mass, more preferably 15 to 35% by mass.

In the present invention, for example, an extended optical film can be obtained by extending the unstretched optical film obtained by the above-mentioned method, uniaxially longitudinally extending in the direction of the mechanical flow, and uniaxially extending in the direction that the mechanical flow is straight, if necessary. film. In addition, a biaxially stretched stretched film can be obtained by stretching by successive biaxial stretching method of roll stretching and tenter stretching, simultaneous biaxial stretching method by tenter stretching, and biaxial stretching method by tubular stretching. The stretching ratio is preferably 0.1% or more and 1000% or less in at least one direction, more preferably 0.2% or more and 600% or less, and particularly preferably 0.3% or more and 300% or less. By designing in this range, a stretched optical film that is preferable from the viewpoints of birefringence, heat resistance, and strength can be obtained.

The optical film of the present invention can be used, for example, for an optical film of a liquid crystal display device from the viewpoint of being excellent in moisture permeability resistance and transparency, and excellent in elastic modulus. Examples of the optical film of the liquid crystal display device include protective films for polarizing plates, retardation films, reflection films, viewing angle improvement films, antiglare films, non-reflection films, antistatic films, color filters, and the like. Among these, it can be preferably used as a protective film for polarizing plates.

The thickness of the optical film is preferably in the range of 20 to 120 μm, more preferably in the range of 25 to 100 μm, and particularly preferably in the range of 25 to 80 μm. When the aforementioned optical film is used as a protective film for a polarizing plate, if the film thickness is in the range of 25 to 80 μm, it is suitable for achieving thinning of the liquid crystal display device, and sufficient film strength, Rth stability, Excellent performance such as moisture permeability resistance.

The optical film of the present invention is characterized in that the modulus of elasticity is higher than that in the case where the ester resin is not blended. Generally speaking, polyester resins that are blended for the purpose of improving the processability of cellulose ester resins can also be called "plasticizers". The ester resin of the present invention has a different performance than the conventional one from the viewpoint of using it as an anti-plasticizer from the viewpoint of increasing the strength with the resin.

Moreover, since the said protective film for polarizing plates does not generate|occur|produce overflow under high temperature and humidity, and can adjust to a desired Rth, it can be widely used in various liquid crystal display systems according to an application.

As the aforementioned liquid crystal display system, for example, IPS (lateral electric field effect display technology: In-Plane Switching), TN (Twisted Nematic: Twisted Nematic), VA (Vertically Aligned: Vertically Aligned), OCB (Optically Compensated Bending) can be mentioned. Type: Optically Compensatory Bend) and so on.

The optical film of the present invention can be appropriately used as a light board protective film, 1/4 wavelength board, 1/4 wavelength board, 1/4 wavelength board, 1/4 wavelength plate, 1/4 wavelength board, 1/4 wavelength board, 1/4 wavelength board, 1/4 wavelength board, 1/4 wavelength board /2 wavelength plate, viewing angle control film, liquid crystal optical compensation film and other retardation films, display front panels, etc. In addition, the resin composition of the present invention can be used for waveguides, lenses, optical fibers, base materials for optical fibers, coating materials, and LEDs in the fields of optical communication systems, optical switching systems, and optical measurement systems. lenses, lens caps, etc.

[Example]

Hereinafter, the present invention will be described more specifically based on examples. The part and % in the example are the quality standard unless otherwise specified.

Example 1

In a 2-liter, three-necked flask, 412 g of 1,2-propanediol (hereinafter abbreviated as "PG") as a diol component, 374 g of isophthalic acid (hereinafter abbreviated as "IPA") as a dicarboxylic acid component, and 374 g as a mono- Benzoic acid (hereinafter referred to as "BzA") as a carboxylic acid component, 611 g, and tetraisopropyl titanate (hereinafter referred to as "TIPT") as a catalyst, 0.08 g, were gradually heated up to 230°C. The condensation reaction was performed at 230° C. for 8 hours, and it was confirmed that the acid value became 1.0 or less. The ester resin (1) of this invention was obtained by removing excess diol at 195 degreeC under reduced pressure. The obtained ester resin (1) was a pale yellow liquid at room temperature, had an acid value of 0.12, a hydroxyl value of 10.0, and a weight average molecular weight of 590. The n=0 component in the GPC measurement was 29 area %, and (n≧3)/(n=0) was 1.0.

Example 2

The same procedure as in Example 1 was carried out using 412 g of PG as a diol component, 280 g of IPA as a dicarboxylic acid component, 82 g of adipic acid (hereinafter abbreviated as "AA"), 611 g of BzA as a monocarboxylic acid component, and 0.08 g of TIPT , to synthesize to obtain ester resin (2). The obtained ester resin (2) was a pale yellow liquid at room temperature, had an acid value of 0.07, a hydroxyl value of 0.0, and a weight average molecular weight of 780. The n=0 component in the GPC measurement was 24 area %, and (n≧3)/(n=0) was 1.1.

Example 3

Using PG 412 g as a diol component, IPA 187 g, AA 164 g as a dicarboxylic acid component, BzA 611 g as a monocarboxylic acid component, and TIPT 0.08 g, it was synthesized in the same manner as in Example 1 to obtain an ester resin (3 ). The obtained ester resin (3) was a pale yellow liquid at room temperature, had an acid value of 0.05, a hydroxyl value of 1.1, and a weight average molecular weight of 670. The n=0 component in the GPC measurement was 25 area %, and (n≧3)/(n=0) was 1.1.

Example 4

Using PG 412 g as a diol component, IPA 94 g, AA 245 g as a dicarboxylic acid component, BzA 611 g as a monocarboxylic acid component, and TIPT 0.08 g, it was synthesized in the same manner as in Example 1 to obtain an ester resin (4 ). The obtained ester resin (4) was a pale yellow liquid at room temperature, had an acid value of 0.08, a hydroxyl value of 5.4, and a weight average molecular weight of 620. The n=0 component in the GPC measurement was 31 area %, and (n≧3)/(n=0) was 0.7.

Example 5

Using 412 g of 1,3-propanediol (hereinafter abbreviated as "13PD") as the diol component, 280 g of IPA and 82 g of AA as the dicarboxylic acid component, 611 g of BzA and 0.08 g of TIPT as the monocarboxylic acid component, and the same as Example 1 In the same manner, synthesis was carried out, whereby ester resin (5) was obtained. The obtained ester resin (5) was a pale yellow liquid at room temperature, had an acid value of 0.11, a hydroxyl value of 8.9, and a weight average molecular weight of 640. The n=0 component in the GPC measurement was 29 area %, and (n≧3)/(n=0) was 0.8.

Example 6

488 g of 2-methyl-1,3-propanediol (hereinafter abbreviated as "2MPD") as a diol component, 280 g of IPA and 82 g of AA as a dicarboxylic acid component, 611 g of BzA and 0.08 g of TIPT as a monocarboxylic acid component were used , was synthesized in the same manner as in Example 1 to obtain ester resin (6). The obtained ester resin (6) was a pale yellow liquid at room temperature, had an acid value of 0.11, a hydroxyl value of 12.6, and a weight average molecular weight of 560. The n=0 component in the GPC measurement was 40 area %, and (n≧3)/(n=0) was 0.4.

Comparative Example 1

In a 2-liter, three-necked flask, 437 g of PG as a diol component, 180 g of phthalic acid (hereinafter abbreviated as "PA") as a dicarboxylic acid component, 178 g of AA, 659 g of BzA as a monocarboxylic acid component, and 0.09 of TIPT were added. g, from a nitrogen introduction tube, the temperature was gradually raised to 220° C. under a nitrogen flow. The condensation reaction was performed at 220° C. for 13 hours, and it was confirmed that the acid value became 1.0 or less. Under reduced pressure, excess diol was removed at 195°C to obtain an ester resin (1') for comparison. The obtained ester resin (1') was a pale yellow liquid at room temperature, had an acid value of 0.09, a hydroxyl value of 1.2, and a weight average molecular weight of 640.

Comparative Example 2

Using PG 313 g, AA 262 g, BzA 436 g, and TIPT 0.10 g as diol components, it was synthesized in the same manner as in Comparative Example 1 to obtain a polyester resin for comparison (2'). The obtained polyester resin for comparison (2') was a pale yellow liquid at room temperature, had an acid value of 0.50, a hydroxyl value of 12.6, and a weight average molecular weight of 610.

Comparative Example 3

Using PG 460 g, dimethyl terephthalate 466 g, BzA 586 g, and TIPT 0.09 g as diol components, it was synthesized in the same manner as in Comparative Example 1 to obtain a polyester resin for comparison (3'). The obtained polyester resin for comparison (3') was a pale yellow viscous liquid at room temperature, the acid value was 0.24, the hydroxyl value was 5.4, and the weight average molecular weight was 650.

Examples 7-12, Comparative Examples 4-7

<Adjustment of cellulose ester optical film>

100 parts of triacetyl cellulose resin ("LT-35" manufactured by Daicel Co., Ltd.), 10 parts of ester resins (1) to (6), and 10 parts of ester resins (1') to (3') were added to a A mixed solvent of 810 parts of methyl chloride and 90 parts of methanol was dissolved to prepare a doping liquid of the cellulose ester resin composition. In Comparative Example 7, the ester resin was not blended, and only the triacetyl cellulose resin was dissolved in the mixed solvent as a doping liquid. The present invention is obtained by casting these doping liquids on a glass plate so as to have a thickness of 0.8 mm or 0.5 mm, drying at room temperature for 16 hours, drying at 50° C. for 30 minutes, and drying at 120° C. for 30 minutes. optical film (60μm or 40μm). About the obtained thin film, physical properties were measured according to the following, and the result is shown in Table 1.

<Measurement of elastic coefficient of optical film>

Installation: Autograph AG-IS manufactured by Shimadzu Corporation

Test piece: 150mm×10mm, 40μm thick rectangle

Between fixtures: 100mm

Test speed: 10mm/min

The larger the modulus of elasticity, the harder the film is expressed.

<Measurement of retardation Rth of optical films>

The Rth value at a wavelength of 590 nm was measured for the optical film using a birefringence measuring apparatus (KOBRA-WR, manufactured by Oji Scientific Instruments Co., Ltd.) at 23° C. in an environment with a relative humidity of 55%.

<Measurement of moisture permeability of optical films>

The measurement was performed according to the method described in JIS Z 0208. The measurement conditions were performed at a temperature of 40° C. and a relative humidity of 90%. The smaller the obtained numerical value, the better the moisture permeability resistance.

Claims (8)

An antiplasticizer for resins for optical materials, comprising an ester resin represented by the following general formula (1); B-(GA) _n -GB (1) [in formula (1), B is selected from the group consisting of One or more residues selected from the group of acetic acid, benzoic acid, p-toluic acid and dimethylbenzoic acid, G is selected from the group consisting of ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2- One or more residues selected from the group of butanediol and 2-methyl-1,3-propanediol, A is selected from the group consisting of succinic acid, adipic acid, dicarboxycyclohexane, phthalic acid, p-benzene One or more residues in the group of dicarboxylic acid and isophthalic acid, 20 mol% or more of the total molar number of A are isophthalic acid residues, n is the number of repetitions, and in each repetition, G , A can be the same or different, and a plurality of B, G can be the same or different]; wherein according to the area ratio in the GPC measurement, the n=0 component in the aforementioned general formula (1) is 10~50%, And the ratio (n≧3)/(n=0) of the area % of the component where n is 3 or more and the area % of the component n=0 is 0.2 or more and 3 or less, the average value of n in the aforementioned general formula (1) is 0.2~3. The antiplasticizer of claim 1, wherein the weight-average molecular weight of the ester resin is in the range of 350 to 1200. The antiplasticizer of claim 1 or 2, wherein 25-100 mol% of the total molar number of A in the general formula (1) is isophthalic acid. The antiplasticizer according to claim 1 or 2, wherein the aforementioned ratio (n≧3)/(n=0) is 0.2 or more and 1.5 or less. A cellulose ester resin composition, characterized in that it contains as claimed in item 1 Antiplasticizer and cellulose ester resin according to any one of to 4. An optical film comprising the cellulose ester resin composition according to claim 5. As claimed in claim 6, the optical film is used for polarizing plate protection. A liquid crystal display device characterized by having the optical film according to claim 6 or 7.