JP2003327800A - Resin composition and optical film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film which shows an excellent antistatic property while retaining good characteristics (heat resistance, transparency and optical properties) inherent in a polymer containing an alicyclic structure. <P>SOLUTION: The resin composition contains the polymer resin containing the alicyclic structure and a lithium alkylbenzene sulfonate. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition having excellent antistatic ability and an optical film suitable for use in flat panel displays such as liquid crystal displays.

[0002]

2. Description of the Related Art In flat panel displays such as liquid crystal displays, various optical films such as polarizing plates, protective films for polarizing plates, retardation films, viewing angle widening films and brightness improving films are used. Then, various problems occur in the manufacturing process of these films. For example, a polarizing plate generally has a structure in which a transparent resin layer is laminated on both sides of a polarizer made of polyvinyl alcohol or the like in which iodine or a dye is adsorbed and oriented, and triacetyl cellulose (hereinafter, referred to as “TAC”). Abbreviated as “.” Is widely used as the transparent resin layer. In the manufacturing process of a liquid crystal display, a decrease in yield and a decrease in productivity due to disturbance of liquid crystal due to static electricity occur. Therefore, in order not to cause such a problem, there is a strong demand for a protective film for a polarizing film, which has an antistatic ability to prevent dust from adhering and to reduce disturbance of liquid crystal due to static electricity.

Polymers containing an alicyclic structure, such as norbornene-based polymers, have a higher glass transition temperature, a higher light transmittance and a lower birefringence than those of TAC which have been used for optical applications. Since it is characterized as such, it is attracting attention as a transparent thermoplastic resin having excellent heat resistance, transparency and optical properties, and its application to optical films is being developed. However, the alicyclic structure-containing polymer has a problem that it is easily charged. Therefore, various studies have been conducted to enhance the antistatic ability of the polymer.

JP-A-5-9351 discloses a cyclic olefin polymer and sodium alkylsulfonate having an alkyl group having 8 to 22 carbon atoms and / or 8 carbon atoms.
Disclosed is a cyclic olefin-based resin composition comprising an alkylsulfonic acid phosphonium salt having an alkyl group of about 22. JP-A-7-252404
Japanese Unexamined Patent Publication (Kokai) discloses a molded product of a thermoplastic resin having a norbornane skeleton, which has an antistatic agent inside and / or on the surface and has a total light transmittance of 85% or more. . The publication discloses sodium alkylbenzene sulfonate as an antistatic agent. Further, Japanese Patent Application Laid-Open No. 2000-53846 discloses a thermoplastic resin composition containing a cyclic polyolefin resin and a fatty acid (partial) ester of a polyhydric alcohol condensate.

[0005]

However, even if the resin compositions described in these publications are formed into a film and used as an optical film, the antistatic ability of the film is still insufficient, and the film is not used as a film. It is required to have additional antistatic capabilities. Therefore, an object of the present invention is to find a film having excellent antistatic ability while maintaining good properties (heat resistance, transparency, optical properties) of the alicyclic structure-containing polymer.

[0006]

Means for Solving the Problems As a result of intensive studies conducted by the present inventors in order to achieve the above object, the use of a specific compound as an antistatic agent results in an optical film having excellent antistatic ability. Based on this finding, further research was conducted, and the present invention was completed.

Thus, according to the present invention, (1) a resin composition containing an alicyclic structure-containing polymer resin and an alkylbenzenesulfonic acid lithium salt, and (2) an alkylbenzenesulfonic acid lithium salt as air. The resin composition according to (1), wherein the 5% weight loss temperature in the atmosphere is 250 ° C. or higher, (3) the resin composition further containing an ultraviolet absorber, (1) or (2) A resin composition, (4) an optical film obtained by molding the resin composition according to any one of (1) to (3),
(5) A polarizing plate protective film comprising the optical film described in (4) and a retardation film obtained by stretching the optical film described in (6) and (4) are provided, respectively.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The resin composition of the present invention is characterized by containing an alicyclic structure-containing polymer resin and an alkylbenzene sulfonic acid lithium salt.

The lithium salt of alkylbenzene sulfonic acid used in the present invention is specifically a compound represented by the following general formula (1). General formula (1): R—C ₆ H ₄ SO ₃ Li (in the above formula, R is a linear or branched alkyl group) Among them, foreign matter is mixed into the molded product due to thermal deterioration during processing of the resin composition. Since it is possible to prevent the occurrence of unevenness in the amount added due to vaporization of the alkylbenzenesulfonic acid lithium salt, it is preferable that the 5% weight loss temperature in the air atmosphere is 250 ° C. or higher. here,
The 5% weight loss temperature in the air atmosphere is the heating when the weight of the alkylbenzene sulfonic acid lithium salt decreases by 5% when heating is performed at a temperature rising rate of 10 ° C. for 1 minute in the air atmosphere. Refers to temperature.

The amount of the alkylbenzene sulfonic acid lithium salt is based on 100 parts by weight of the alicyclic structure-containing polymer resin.
It is preferably 0.1 to 2.0 parts by weight, more preferably 0.1 to 1.5 parts by weight. By setting the amount of the alkylbenzene sulfonic acid lithium salt in the above range, an optical film having excellent antistatic ability and excellent optical characteristics can be obtained.

The alicyclic structure-containing polymer resin used in the present invention contains an alicyclic structure in the repeating unit of the polymer, and the alicyclic structure is present in either the main chain or the side chain. May be. As the alicyclic structure, a cycloalkane structure,
Examples thereof include a cycloalkene structure, but a cycloalkane structure is preferable from the viewpoint of thermal stability and the like. The number of carbon atoms constituting the alicyclic structure is usually 4 to 30, preferably 5
-20, more preferably 5-15. When the number of carbon atoms constituting the alicyclic structure is within this range, a product having excellent heat resistance and flexibility can be obtained. The proportion of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer resin is
It may be appropriately selected depending on the purpose of use, but is usually 50% by weight or more, preferably 70% by weight or more, more preferably 9% by weight or more.
It is 0% by weight or more. If the proportion of the repeating unit having an alicyclic structure is excessively low, the heat resistance decreases, which is not preferable.
The repeating unit other than the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer resin is appropriately selected according to the purpose of use.

Specific examples of the alicyclic structure-containing polymer resin include (1) a norbornene-based polymer, (2) a monocyclic cycloolefin polymer, (3) a cyclic conjugated diene polymer,
(4) Vinyl alicyclic hydrocarbon polymer, and (1) to
Examples thereof include the hydride of (4). Among these,
From the viewpoint of heat resistance, mechanical strength, and the like, norbornene-based polymer hydrides, vinyl alicyclic hydrocarbon polymers and hydrides thereof are preferable.

(1) Norbornene-based polymer The norbornene-based polymer used in the present invention is a ring-opening polymer of a norbornene-based monomer, or a ring-opening copolymer of a norbornene-based monomer and another monomer capable of ring-opening copolymerization. Examples thereof include polymers, hydrides thereof, addition polymers of norbornene-based monomers, and addition copolymers of norbornene-based monomers with other monomers copolymerizable therewith. Among these, the hydrogenated ring-opening polymer of the norbornene-based monomer is most preferable from the viewpoint of heat resistance, mechanical strength and the like.

The norbornene-based monomers include bicyclo [2.2.1] -hept-2-ene (common name: norbornene) and its derivatives (having a substituent on the ring),
Tricyclo ^{[4.3.1 2,5.} 0 ^1,6 ] -deca-
3,7-Diene (common name dicyclopentadiene) and its derivatives, tetracyclo [7.4.11 ^10,13 . 0 ^{1
, 9} . 0 ^2,7 ] -Trideca-2,4,6,11-tetraene (also referred to as 1,4-methano-1,4,4a, 9a-tetrahydrofluorene: trivial name methanotetrahydrofluorene) and its derivative, tetracyclo [4 .4.
1 ^2,5 . 1 ^{7, 10} . 0] -dodec-3-ene (conventional name: tetracyclododecene) and its derivatives. Examples of the substituent include an alkyl group, an alkylene group, a vinyl group, an alkoxycarbonyl group, and the like, and the norbornene-based monomer may have two or more kinds thereof. Specifically, 8-methoxycarbonyl - tetracyclo ^{[4.4.1 2,5.} 1 ^{7, 10} .
0] - dodeca-3-ene, 8-methyl-8-methoxycarbonyl - tetracyclo ^{[4.4.1 2,5.} 1
^7,10 . 0] -dodeca-3-ene and the like.
These norbornene-based monomers may be used alone or in combination of two or more.

The ring-opening polymer of these norbornene-based monomers, or the ring-opening copolymer of the norbornene-based monomer and other monomer capable of ring-opening copolymerization contains a monomer component in the presence of a known ring-opening polymerization catalyst. It can be obtained by polymerizing under. As the ring-opening polymerization catalyst, for example, ruthenium, a metal halide such as osmium, and a catalyst comprising a nitrate or an acetylacetone compound, and a reducing agent, or titanium, zirconium, tungsten,
A catalyst composed of a metal halide such as molybdenum or an acetylacetone compound and an organoaluminum compound can be used. Examples of the other monomer capable of ring-opening copolymerization with the norbornene-based monomer include monocyclic cycloolefin-based monomers such as cyclohexene, cycloheptene, and cyclooctene.

The hydrogenated ring-opening polymer of the norbornene-based monomer is usually carbon-carbon unsaturated by adding a known hydrogenation catalyst containing a transition metal such as nickel or palladium to the polymerization solution of the above ring-opening polymer. It can be obtained by hydrogenating the bond.

The addition polymer of the norbornene-based monomer or the addition (co) polymer of the norbornene-based monomer and another monomer copolymerizable with the norbornene-based monomer is obtained by adding these monomers to a known addition polymerization catalyst such as titanium, It can be obtained by (co) polymerization using a catalyst composed of a zirconium or vanadium compound and an organic aluminum compound.

Other monomers copolymerizable with the norbornene-based monomer include, for example, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene. , 1-hexadecene, 1-octadecene, 1-eicosene, and other α-olefins having 2 to 20 carbon atoms, and derivatives thereof; cyclobutene, cyclopentene, cyclohexene, cyclooctene, 3a, 5,6,7a-tetrahydro-4, Cycloolefins such as 7-methano-1H-indene, and their derivatives; 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-
Non-conjugated dienes such as 1,4-hexadiene and 1,7-octadiene; and the like are used. Among these, α-
Olefins, especially ethylene, are preferred.

These other monomers copolymerizable with the norbornene-based monomer may be used alone or in combination of two or more kinds. In the case of addition-copolymerizing a norbornene-based monomer with another monomer copolymerizable with the norbornene-based monomer, the ratio of the structural unit derived from the norbornene-based monomer to the structural unit derived from the other copolymerizable monomer in the addition copolymer. However, the weight ratio is usually 30:70 to 99: 1, preferably 50:50 to 97 :.
3, more preferably, it is appropriately selected to be in the range of 70:30 to 95: 5.

(2) Monocyclic Cyclic Olefin Polymer As the monocyclic cycloolefin polymer, for example, an addition polymer of a monocyclic cycloolefin monomer such as cyclohexene, cycloheptene or cyclooctene is used. be able to.

(3) Cyclic Conjugated Diene Polymer As the cyclic conjugated diene polymer, 1,2- or 1,4-addition polymerization of a cyclic conjugated diene monomer such as cyclopentadiene or cyclohexadiene is carried out. Polymers and hydrides thereof can be used.

The molecular weight of the norbornene-based polymer, monocyclic cyclic olefin-based polymer or cyclic conjugated diene-based polymer is
It is appropriately selected depending on the purpose of use, but it is usually a weight average molecular weight in terms of polyisoprene or polystyrene measured by gel permeation chromatography of a cyclohexane solution (a toluene solution when the polymer resin is not dissolved), usually 5, 000 to 500,000, preferably 8,000 to 200,000, more preferably 10.0.
When it is in the range of 00 to 100,000, the mechanical strength of the resin composition and the moldability are highly balanced, which is preferable.

(4) Vinyl alicyclic hydrocarbon polymer Examples of the vinyl alicyclic hydrocarbon polymer include polymers of vinyl alicyclic hydrocarbon type monomers such as vinyl cyclohexene and vinyl cyclohexane, and hydrogens thereof. A hydride of an aromatic ring portion of a polymer of a vinyl aromatic monomer such as styrene or α-methylstyrene; and a vinyl alicyclic hydrocarbon polymer or a vinyl aromatic monomer. ,
Random copolymers of these monomers with other copolymerizable monomers, copolymers such as block copolymers, and hydrides thereof may be used. Examples of the block copolymer include a diblock, a triblock, or a multiblock or a gradient block copolymer of more than that, and there is no particular limitation.

The molecular weight of the vinyl alicyclic hydrocarbon polymer is
It is appropriately selected depending on the purpose of use, but it is usually 10 in terms of weight average molecular weight in terms of polyisoprene or polystyrene measured by gel permeation chromatography of a cyclohexane solution (toluene solution when the polymer resin is not dissolved). 1,000 to 300,000, preferably 1
5,000 to 250,000, more preferably 20,0
When it is in the range of 00 to 200,000, the mechanical strength and molding processability of the resin composition are highly balanced, which is preferable.

The glass transition temperature (Tg) of the alicyclic structure-containing polymer resin used in the present invention may be appropriately selected according to the purpose of use, but is preferably 80 ° C. or higher, more preferably 130 ° C. Is in the range of up to 200 ° C. Within this range, no deformation or stress occurs even when used at high temperatures, and the durability is excellent.

It is preferable that the resin composition of the present invention further contains an ultraviolet absorber. Examples of the ultraviolet absorber include oxybenzophenone compounds, benzotriazole compounds, salicylate compounds, benzophenone compounds, cyanoacrylate compounds,
Examples thereof include nickel complex salt compounds, but are not limited thereto. You may use 2 or more types of ultraviolet absorbers. Above all, from the viewpoint of preventing deterioration of liquid crystal when the optical film of the present invention is used in a liquid crystal display, it is 5% in air.
Weight loss temperature is 300 ° C. or higher, and wavelength in a 1 wt% chloroform solution is 370 nm, 380 nm, 400 n
The absorbance at m is preferably 0.27 or more, 0.092 or more, and 0.03 or less. By doing so, it is possible to obtain an optical film having a good UV-cutting property and a small yellow coloring. The amount C (parts by weight) of the ultraviolet absorber is 92 / t <C <2 when the thickness of the optical film to be obtained is t (μm).
It is preferable to satisfy 31 / t. When C is less than the above range, the UV blocking property is insufficient, and when C is more than the above range, yellow coloring tends to be large.

In the resin composition of the present invention, if necessary,
Known additives such as anti-blocking agents, antioxidants, plasticizers, colorants, lubricants and the like may be added. These additives can be used alone or in combination of two or more, and the blending amount thereof is appropriately selected within a range that does not impair the object of the present invention.

As the method for producing the resin composition of the present invention, for example, an alicyclic structure-containing polymer resin, an alkylbenzene sulfonic acid lithium salt and other components are used in a twin-screw extruder, roll kneader or the like. A method of obtaining a pellet-shaped resin composition by mixing, a method of dissolving and dispersing an alicyclic structure-containing polymer resin, an alkylbenzene sulfonic acid lithium salt and other components in a suitable solvent to coagulate. . When a twin-screw kneader is used, it is usually used by extruding it into a strand in a molten state after kneading and cutting it into pellets with a pelletizer.

The optical film of the present invention is obtained by molding the resin composition.

The thickness of the optical film of the present invention may be selected according to the application, but it is generally 20 to 200 μm.
The range is m.

The total light transmittance of the optical film of the present invention is preferably 90% or more.

The retardation magnitude Re of the optical film of the present invention is preferably 5 nm or less, and its retardation unevenness is preferably within ± 1 nm. When Re is in such a range, when the optical film is used in a liquid crystal display or the like, it is possible to reduce color unevenness or color loss of the liquid crystal display.

The photoelastic coefficient of the optical film of the present invention is
It is preferably 10 to 90 m ² / N. When the photoelastic coefficient is in this range, it is possible to prevent a phase difference due to stress from occurring.

The saturated water absorption of the optical film of the present invention is
Preferably 0.05% or less, more preferably 0.01
% Or less. When the saturated water absorption exceeds the above range, a dimensional change occurs in the film during use and internal stress occurs, and for example, when the film is used in a reflective liquid crystal display device, black display is partially thin. There is a possibility that display unevenness, such as "(looks whitish)" may occur. Therefore, when the saturated water absorption is within the above range, the display is stable even after long-term use without causing display unevenness.

As a method for obtaining the optical film of the present invention, either a hot melt molding method or a solution casting method can be used. From the viewpoint of reducing volatile components in the film, the hot melt molding method is used. It is preferable to use. The hot melt molding method can be classified in more detail into an extrusion molding method, a press molding method, an inflation molding method, an injection molding method, a blow molding method and the like. Among these methods, in order to obtain an optical film having excellent mechanical strength and surface accuracy, it is preferable to use melt extrusion molding, particularly melt extrusion molding using a T die. The molding conditions are appropriately selected depending on the purpose of use and the molding method, but in the case of melt extrusion molding,
The cylinder temperature is appropriately set within the range of preferably 100 to 400 ° C, more preferably 170 to 300 ° C. The temperature of the roll when the melt-extruded film-shaped resin composition is taken up by the roll is preferably 80 to 180 ° C.

The optical film of the present invention is excellent in antistatic ability while maintaining the good properties (heat resistance, transparency, optical properties) of the alicyclic structure-containing polymer, so that it can be used in flat panels such as liquid crystal displays. It can be used as an optical film such as a polarizing plate, a polarizing plate protective film, a retardation film, a viewing angle widening film and a brightness improving film used for a display. Above all, it is suitable for a polarizing plate protective film and a retardation film.

When the optical film of the present invention is used as a polarizing plate protective film, it is laminated on one side or both sides of the polarizing plate via an appropriate adhesive. The polarizing plate is obtained by doping a polyvinyl alcohol-based film with iodine or the like and then stretching the film. As the adhesive layer, a pressure-sensitive adhesive having an appropriate polymer such as acrylic polymer, silicone polymer, polyester, polyurethane, polyether or synthetic rubber as a base polymer is used.

When the optical film of the present invention is used as a retardation film, it is stretched so as to have a desired retardation. The retardation film is a film that gives a predetermined phase difference between linearly polarized lights that vibrate in mutually perpendicular directions when passing through the film. The phase difference is λ, λ / 2, λ / 4 (where λ is The wavelength of the light used in vacuum)
Those are referred to as a one-wave plate, a half-wave plate, and a quarter-wave plate, respectively. For example, a tenter is used to stretch the optical film of the present invention. The temperature of the film during stretching is, for example, (Tg−100) ° C. or higher and (Tg + 4).
0) C. or less. Here, Tg is a glass transition temperature of the alicyclic structure-containing polymer resin as a raw material. The stretching ratio depends on the retardation value to be obtained and the thickness of the retardation film, but is usually 1.05 in the length direction (extrusion direction of the alicyclic structure-containing polymer resin film). It is not less than 2 times and not more than 3.0 times and not more than 0.2 times in the width direction, and in some cases uniaxial stretching in the length direction. The retardation unevenness of the stretched film is preferably ± 1.5 nm or less.

The retardation film may be used alone or in combination of two or more.

[0040]

EXAMPLES The method of the present invention will be described in more detail by showing examples, but the present invention is not limited to the following examples. Parts and% are based on weight unless otherwise specified. The evaluation in this example is performed by the following method. (1) Molecular weight Tetrahydrofuran (THF) is used as a solvent and measured by gel permeation chromatography (GPC) to obtain a weight average molecular weight (Mw) in terms of standard polystyrene.

(2) Glass transition temperature (Tg) Differential scanning calorimetry (D) based on JIS K7121
SC). (3) Hydrogenation rate The hydrogenation rates of the main chain and aromatic ring of the polymer are calculated by measuring ¹ H-NMR. (4) Film thickness offline film thickness measuring device (TOF-4 manufactured by Yamabun Electric Co., Ltd.)
R).

(5) Total Light Transmittance of Film The total light transmittance of the film is measured based on ASTM D1003 using a turbidimeter NDH-300A manufactured by Nippon Denshoku Industries Co., Ltd. The higher this value is, the more preferable as an optical film. (6) Surface resistance value The surface resistance value of the film is as follows: temperature 23 ° C, relative humidity 50%.
It is left for 2 days under the environment of No. 2 and then measured by a surface resistance meter (digital ultra-high resistance meter "R8340" manufactured by Advantest). The smaller this value is, the more preferable as an optical film.

(7) The bright spot film is cut out into a size of 100 mm × 100 mm and used as a film 1. The entire surface of this film is rubbed 10 times with gauze. Place the film 1 on the diffusion sheet 4 of the backlight unit (see FIG. 1) using the cold-cathode tube 1 as the lamp light source, which is equipped with the 14-inch light guide plate 3, and visually check the number of bright spots on the film. Counted by. ○ with a number of bright spots of 0 on the entire surface of the film
The case where the number of bright points is 1 to 3 is Δ, and the case where the number of bright points is 4 or more is x.

(Production Example 1) In a nitrogen atmosphere, 500 parts of dehydrated cyclohexane was mixed with 0.82 parts of 1-hexene, 0.15 parts of dibutyl ether and 0.30 parts of triisobutylaluminum at room temperature and mixed. Then, while maintaining at 45 ° C., 8-methyl-tetracyclo [4.4.0.
1 ^2,5 . 1 ^7,10 ] -dodeca-3-ene (hereinafter,
100 parts by weight, and tungsten hexachloride (0.
40 parts of 7% toluene solution) were continuously added over 2 hours to polymerize. 1.06 parts of butyl glycidyl ether and 0.52 parts of isopropyl alcohol were added to the polymerization solution to inactivate the polymerization catalyst to stop the polymerization reaction.

Then, to 100 parts of the reaction solution containing the obtained ring-opening polymer, 270 parts of cyclohexane was added, and further 5 parts of a nickel-alumina catalyst (manufactured by JGC Chemical Co., Ltd.) as a hydrogenation catalyst was added, and hydrogen was added. Then, the pressure was increased to 5 MPa and the temperature was raised to 200 ° C. with stirring, and then the reaction was carried out for 4 hours to obtain a reaction solution containing 20% of the hydride of the MTD ring-opening polymer. After removing the hydrogenation catalyst by filtration, an antioxidant (manufactured by Ciba Specialty Chemicals; Irganox 1010) was added and dissolved in the obtained solution in an amount of 0.1 part per 100 parts of the polymer. Then, using a cylindrical concentrating dryer (manufactured by Hitachi, Ltd.), at a temperature of 270 ° C. and a pressure of 1 kPa or less, the hydride is extruded in a molten state while removing the solvent cyclohexane and other volatile components from the solution. Extruded in strands from
After cooling, it was pelletized and the pellets were collected. The weight average molecular weight (Mw) of this hydrogenated ring-opening polymer was 35,000.
0, the hydrogenation rate was 99.9%, and the Tg was 142 ° C.

(Example 1) 1 part of a lithium salt of alkylbenzene sulfonic acid (trade name "NZS-213" manufactured by Takemoto Yushi Co., Ltd., 5% weight loss temperature 334 ° C) was added to 100 parts of the pellet obtained in Production Example 1. Was added and melt-extruded from a coat hanger type T die having a width of 300 mm using a single-screw extruder having a screw of 20 mmφ to produce a film having a thickness of 40 μm. The molten resin temperature at this time was 260 ° C. The total light transmittance, surface resistance value and bright spot of the film were evaluated. The evaluation results are shown in Table 1.

Example 2 To 100 parts of the pellet obtained in Production Example 1, 1 part of lithium salt of alkylbenzene sulfonic acid and an ultraviolet absorber (Adeka Stab LA manufactured by Asahi Denka Co., Ltd.)
-31, 5% weight loss temperature 373 ° C, absorbance 370n
m, 380 nm, 400 nm, 0.27, 0.
092, 0.030) A film was formed and evaluated in the same manner as in Example 1 except that 1 part was added. The evaluation results are shown in Table 1.

Comparative Example 1 A film was prepared in the same manner as in Example 1 except that sodium alkylbenzene sulfonate (Sanyo Chemical Co., Ltd., product name “Chemist 3100”) was added in place of lithium alkylbenzene sulfonate. It was molded and evaluated. The evaluation results are shown in Table 1.

(Comparative Example 2) Instead of the alkylbenzene sulfonic acid lithium salt, sodium alkyl sulfonate (manufactured by Kao Corporation, product name "Electro Clipper PC")
2 ”) was added, and a film was formed and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

(Comparative Example 3) Comparative Example 3 was repeated except that a phosphonium alkylsulfonic acid phosphonium salt (manufactured by Takemoto Yushi Co., Ltd., product name "Elecut 605") was added in place of the lithium alkylbenzenesulfonate in Example 1. Similarly, a film was formed and evaluated. The evaluation results are shown in Table 1.

(Comparative Example 4) Instead of the alkylbenzene sulfonic acid lithium salt, stearic acid monoglyceride (manufactured by Kao Corporation, product name "Electrostripper TS-") was used.
5 ”) was added, and a film was formed and evaluated in the same manner as in Example 1. The evaluation results are shown in Table 1.

[0052]

[Table 1]

The following can be seen from the results in Table 1. According to the present invention, an optical film obtained by molding a resin composition comprising an alicyclic structure-containing polymer resin and an alkylbenzene sulfonic acid lithium salt has a high total light transmittance and a surface. Since the resistance value is small, there is no bright spot on the liquid crystal display screen. On the other hand, in the comparative example, since the antistatic performance is poor, bright spots are present on the liquid crystal display screen.

[0054]

INDUSTRIAL APPLICABILITY The resin composition of the present invention has excellent antistatic ability while maintaining good properties (for example, high total light transmittance) of the alicyclic structure-containing polymer. Polarizing plate, polarizing plate protective film, retardation film,
It is useful as an optical film such as a viewing angle widening film and a brightness enhancement film. Then, by using this optical film, it is possible to prevent the disturbance of the liquid crystal and the destruction of the transistor of the liquid crystal unit due to static electricity.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a backlight unit for evaluating an optical film of the present invention.

[Explanation of symbols]

1: Cold cathode tube 2: Reflector 3: Light guide plate 4: Diffusion sheet 5: Reflective sheet 6: Film

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Claims (6)

[Claims] 1. A resin composition comprising an alicyclic structure-containing polymer resin and an alkylbenzene sulfonic acid lithium salt. 2. A lithium 5% alkylbenzene sulfonate having a 5% weight loss temperature of 250 ° C. in an air atmosphere.
The resin composition according to claim 1, wherein the resin composition described above is used. 3. The resin composition according to claim 1, which further comprises an ultraviolet absorber. 4. An optical film obtained by molding the resin composition according to any one of claims 1 to 3. 5. A polarizing plate protective film comprising the optical film according to claim 4. 6. A retardation film obtained by stretching the optical film according to claim 4.