JP4616787B2 - Resin composition - Google Patents

Description

  The present invention relates to an optical resin composition excellent in transparency, low photoelasticity and processability, an optical film comprising the same, a retardation film useful for a liquid crystal display device, and a substrate for a liquid crystal display device. More specifically, the present invention relates to a resin composition excellent in transparency, low birefringence, heat resistance, moisture resistance, and film forming property, obtained by mixing an amorphous thermoplastic resin and a vinyl-based low molecular weight polymer. The present invention relates to an optical film, a retardation film, and a substrate for a liquid crystal display device.

  Amorphous thermoplastic resins such as polycarbonate are used as optical parts such as optical films because of their transparency. For example, in a liquid crystal display device, a retardation film is laminated between a liquid crystal cell and a polarizing plate in order to improve image visibility. This retardation film serves to convert elliptically polarized light transmitted through the liquid crystal layer into linearly polarized light. As the material, a uniaxially stretched film of polycarbonate resin mainly composed of bisphenol A is used and put into practical use. The reason is that the properties required for the retardation film are excellent, such as (1) high transparency, (2) high refractive index anisotropy, and (3) relatively high heat resistance.

However, stress is generated due to uneven bonding when the film is bonded to the liquid crystal cell together with the polarizing plate, difference in thermal expansion between constituent materials due to receiving heat from the backlight or the external environment, contraction of the polarizing film, etc. . As a result, since the polycarbonate film made of bisphenol A has a high photoelastic coefficient, phase difference unevenness due to photoelastic birefringence occurs, and there is a problem that color balance and contrast of the display image are likely to be reduced. Yes.
In order to overcome this problem, it is conceivable to use a film material in which the phase difference does not easily change due to stress, that is, the photoelastic coefficient is small. As materials having a small photoelastic coefficient, olefin-based materials found in Japanese Patent Application Laid-Open No. 07-287122 and special polycarbonate resins found in International Publication WO95 / 233353 are known. However, when an olefin-based material is used, birefringence hardly develops even when the film is oriented, and when it is stretched to obtain a retardation film, it is difficult to obtain an arbitrary retardation value. The film has a problem that it is difficult to industrially obtain a film having a large retardation ratio and having a uniform retardation value.

In the case of a special polycarbonate resin, the photoelastic coefficient is reasonably small, and the addition of a phase difference due to orientation is not particularly problematic in industrial implementation. In addition to being able to use the existing stretching device as it is and requiring a special stretching device with high heat resistance, it is difficult to perform uniform stretching due to the high stretching temperature, resulting in large variations in retardation in a wide range. Has drawbacks. In order to reduce this heat resistance, a plasticizer is used. In the case of monomer plasticizers, there is a problem of oozing out of the film when the amount used is increased, and in the case of high molecular weight polymer plasticizers, there is an increase in haze due to incompatibility, a decrease in transmittance, that is, a decrease in transparency. There's a problem.
JP 07-287122 A International Publication WO95 / 233353

  An object of the present invention is to provide an optical resin composition and an optical film that are excellent in transparency and processing characteristics, have a small photoelastic coefficient, and are less likely to cause display unevenness due to stress.

  As a result of diligent investigations to solve such problems, the present inventors have found that such problems can be solved by mixing a specific vinyl-based low molecular weight polymer with an amorphous thermoplastic resin, thereby completing the present invention. It came.

（ｘは２０モル％以上、ｙは８０モル％以下）
で表される繰り返し単位からなるポリカーボネート樹脂であり、光弾性係数が４０×１０^−１３cm^２／ｄｙｎｅ以下である光学フィルムを内容とする。
本発明の他実施形態では、該光学フィルムを延伸して得られることを特徴とする位相差フィルムを内容とする。 That is, the present onset Ming is an optical film composed of a resin composition containing a polystyrene amorphous thermoplastic resin and a number average molecular weight of 200-4000 0.1 to 30 wt%, amorphous thermoplastic The resin is represented by the following general formula (3)

(X is 20 mol% or more, y is 80 mol% or less)
The content is an optical film having a photoelastic coefficient of 40 × 10 ⁻¹³ cm ² / dyne or less.
Another embodiment of the present invention includes a retardation film obtained by stretching the optical film.

  In still another embodiment of the present invention, the content is a transparent conductive film characterized in that a transparent electrode layer is provided on at least one surface of the optical film.

  Still another embodiment of the present invention includes a liquid crystal display device using the transparent conductive film as an electrode substrate.

  Still another embodiment of the present invention includes a touch panel using the transparent conductive film as an electrode substrate.

  According to the present invention, it is possible to obtain an optical film having little change in retardation due to stress and having appropriate orientation and heat resistance. By using the optical film, it is possible to obtain a retardation film, a transparent conductive film, a liquid crystal display device, and a touch panel, whose display characteristics are unlikely to deteriorate with respect to stress.

  The first resin composition in the present invention contains an amorphous thermoplastic resin and a vinyl low molecular weight polymer having a number average molecular weight of 200 to 10,000 as essential components.

  The amorphous thermoplastic resin is selected from polycarbonate, polyester, polysulfone, polyether and copolymers thereof.

  The number average molecular weight of the thermoplastic resin of the present invention is preferably 10,000 to 110,000, more preferably 15,000 to 80,000.

  As the vinyl-based low molecular weight polymer, one or two or more kinds selected from the group consisting of vinyl aromatic compounds, acrylic esters, methacrylic esters, maleic esters, N-substituted maleimides, acrylonitrile, methacrylonitrile, vinyl esters Selected from polymers.

  The second resin composition in the present invention has the following general formula (1):

And a vinyl low molecular weight polymer having a number average molecular weight of 200 to 10,000 as essential components. In the formula, R _{1 to} R ₄ are a hydrogen atom or a methyl group. In the formula, X is a cycloalkylene group having 5 to 10 carbon atoms or an aralkylene group having 7 to 15 carbon atoms.

Examples of the cycloalkylene group include 1,1-cyclopentylene, 1,1-cyclohexylene, 1,1- (3,3,5-trimethyl) cyclohexylene, norbornane-2,2-diyl, and tricyclo [5.2. 1.0 ^2,6 ] decane-8,8'-diyl and the like are increased, and 1,1-cyclohexylene, 1,1- (3,3,5) is obtained from the viewpoint of price and availability of raw materials. -Trimethyl) cyclohexylene is preferably used.

  Examples of the aralkylene group include phenylmethylene and 1,1- (1-phenyl) ethylene.

  The third resin composition in the present invention has the general formula (1).

And a repeating unit represented by the general formula (2)

And a vinyl low molecular weight polymer having a number average molecular weight of 200 to 10,000 as essential components.

In general formula (2), R < ₁ > -R < ₄ > is a hydrogen atom or a methyl group, and may be the same or different. In the formula, Y is an alkylene group having 1 to 5 carbon atoms or an aralkylene group having 7 to 15 carbon atoms.

  Examples of the alkylene group include methylene, 1,1-ethylene, 2,2-propylene, 2,2-butylene and 2,2- (4-methyl) pentylene.

  Moreover, as an aralkylene group, the same thing as what was mentioned by General formula (1) is mentioned.

  The ratio of the repeating unit represented by the general formula (1) and the repeating unit represented by the general formula (2) is not particularly limited. For example, the former is 20 mol% or more and the latter is 80 mol% or less. Resins are excellent in that they have low photoelasticity.

  The composition of the present invention is generally processed into a film by a casting method from a solution or a melt extrusion method. However, since an optical film is required to have a high degree of uniformity, a casting method from a solution is preferably used. Solvents include haloalkanes such as dichloromethane, chloroform and 1,2-dichloroethane, cyclic ethers such as tetrahydrofuran, 1,3-dioxolane and 1,4-dioxane, ketones such as methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, and chlorobenzene. Aromatic solvents such as are used. Of these, dichloromethane, 1,2-dichloroethane, 1,3-dioxolane, 1,4-dioxane, cyclohexanone, chlorobenzene and the like are particularly preferable from the viewpoints of solubility and dope stability. These may be a single solvent or a mixed solvent of two or more. As the concentration of the resin, 15 to 35% by weight is used for the optical film of the present invention.

  When a film is produced using the resin composition of the present invention, since the photoelastic coefficient is small, a phase difference is hardly generated due to stress, and a high-quality film can be produced with high productivity.

  Although the film thickness of the film of the present invention may be selected according to the use, it is generally 10 to 500 μm, preferably 30 to 300 μm, more preferably 50 to 100 μm.

  The molecules of the film of the present invention can be oriented to make a retardation film. In general, molecules can be oriented by heating and stretching uniaxially or biaxially. As the uniaxial stretching method, an arbitrary method such as a lateral uniaxial stretching by a tenter method, a longitudinal uniaxial stretching between rolls, or an inter-roll rolling method is used. In addition, if necessary, a wet stretching method can be employed. In order to control the three-dimensional refractive index of the film, a special stretching method such as that disclosed in JP-A-2-160204, JP-A-4-230704, JP-A-5-157911 and the like is also suitable. Can be used. The stretching temperature depends on the glass transition temperature (Tg) of the resin used, and a range of (Tg-30) ° C to (Tg + 30) ° C, preferably (Tg-20) ° C to (Tg + 20) ° C is used. If the temperature is lower than this range, uniform alignment becomes difficult, and if it is higher than this range, the orientation is relaxed and the expected degree of alignment cannot be obtained, and the alignment control becomes difficult. A preferable range of the phase difference can be appropriately selected depending on the application. Generally, when used as a λ / 4 retardation film, a range of 100 nm to 200 nm is selected, and when used as a λ / 2 retardation film, a range of 200 nm to 350 nm is selected. Further, when used for color compensation of the STN type liquid crystal display device, it is selected in the range of 400 nm to 2000 nm depending on the method of the liquid crystal display device. The required phase difference can be obtained by adjusting the stretching temperature and the stretching ratio.

  Examples of vinyl low molecular weight polymers used in the composition of the present invention include vinyl aromatic compounds, acrylic acid esters, methacrylic acid esters, maleic acid esters, N-substituted maleimides, acrylonitrile, methacrylonitrile, and vinyl esters. One or more polymers selected from the group. The amount added is 0.1 to 30% by weight of the resin, preferably 1 to 20% by weight.

  Moreover, this invention film can be used suitably also as a board | substrate for liquid crystal display devices. The liquid crystal display device using the film of the present invention has a characteristic that the display quality is not deteriorated because no phase difference is generated even when stress is applied to the substrate due to contraction of the polarizing plate under the use environment. . When used as the substrate, the phase difference of the film is 20 nm or less, more preferably 10 nm or less, the phase difference variation is preferably 10% or less, and the direction variation of the absorption axis is in the range of ± 5 °. It is desirable. In order to prevent the display image from changing depending on the viewing angle, it is preferable to keep the biaxiality of the film small. Ratio (R (45) / R (0)) of the phase difference R (0) measured from the surface direction of the film and the phase difference (R (45)) measured by tilting 45 ° in the direction perpendicular to the optical axis Thus, the biaxiality of the film can be expressed. R (45) / R (0) is preferably 5 or less, more preferably 3 or less, and still more preferably 1.5 or less. When the liquid crystal display device is an STN type liquid crystal display device, the retardation film can be used as the substrate for the liquid crystal display device.

  When used as a substrate for a liquid crystal display device, a gas barrier layer composed of a single layer or a plurality of layers and a transparent electrode layer are generally formed on at least one surface of the film to provide barrier properties against oxygen and water vapor.

  Various gas barrier layers can be used as the gas barrier layer. Before forming the gas barrier layer, an anchor coating may be applied in order to improve adhesion to the film. Organic material-based gas barrier layers include polyvinyl alcohol, vinyl alcohol polymers such as vinyl alcohol-ethylene copolymer, polyacrylonitrile, acrylonitrile-methyl acrylate copolymer and acrylonitrile-styrene copolymer acrylonitrile. A layer made of a polymer or an organic polymer material such as polyvinylidene chloride can be used. These materials can be formed on the film of the present invention by a wet coating method using a gravure coater or a reverse coater to form a gas barrier layer. When a polyvinyl alcohol-based barrier layer is used, it is preferable to separately form a water vapor barrier layer because oxygen barrier properties are drastically lowered due to moisture absorption.

In addition, as the inorganic gas barrier layer, silicon dioxide or a compound containing this as a main component and containing one or more metal oxides such as silicon monoxide and aluminum oxide, and / or silicon nitride, or this is used. A compound containing as a main component and containing one or more metal nitrides such as aluminum nitride can be used. Specific examples of this compound include SiO _x and SiAlN. Among the inorganic barrier thin films, that is, metal oxides mainly composed of silicon oxide and / or metal nitrides mainly composed of silicon nitride, the value of SiO _x , particularly x is 1.3 to 1.8. In view of oxygen gas and water vapor barrier properties, it is preferably 1.5. These inorganic barrier layers can be formed by chemical vapor deposition (CVD) as well as physical vapor deposition (PVD) such as sputtering or electron beam evaporation. Alternatively, an organic metal compound layer such as polysilazane may be formed on the film of the present invention and then thermally decomposed.

  These barrier layers may be used alone or in combination. In particular, when an organic barrier layer and an inorganic barrier layer are used in combination, the excellent resistance of the organic barrier layer to crack pinholes in the barrier layer and the excellent resistance of the inorganic barrier layer particularly to water vapor have a synergistic effect. A particularly preferred combination. Among these, a combination of a polyvinyl alcohol-based barrier layer and a silica or alumina barrier layer formed by an electron beam evaporation method is most preferable in terms of characteristics. At this time, an anchor coat layer can be provided between the respective layers for the purpose of improving the adhesion of the respective layers. As the anchor coat layer, a siloxane-based cured product such as polydimethylsiloxane or a urethane / epoxy-based cured product layer is preferably used. The method for forming these cured product layers is not particularly limited, and a thermal curing method, an ultraviolet curing method, or an electron beam curing method can be used. In order to protect the organic barrier layer from the outside, it is preferable to form a cured product layer on the organic barrier layer and further form an inorganic barrier layer. Therefore, an inorganic barrier is formed on the cured product, but the inorganic barrier layer is subject to undesirable changes in the film quality formed when the low molecular weight material from the substrate on which the layer is formed volatilizes during film formation. May not be obtained. As a method for curing a cured product, the electron beam curing method has a feature that the amount of uncured product can be reduced without heating to a high temperature, and is a preferable curing method.

Further, the transparent electrode layer is provided on the uppermost layer in various processing, and a metal oxide mainly composed of indium oxide is preferable. Depending on the purpose, the layer may be directly formed on the film of the present invention or may be formed on the barrier layer, and an intermediate layer for improving adhesion is provided on the barrier layer. May be formed. When used as an electrode of a liquid crystal display device, the transparent conductive layer has a thickness of about 20 to 400 nm, preferably about 50 to 200 nm, more preferably 80 to 150 nm, a light transmittance of 80% or more, preferably 85% or more, and a sheet. A transparent conductive thin film having a resistance of 100Ω / □ or less, preferably 50Ω / □ or less. When the thickness of the transparent conductive thin film is in the range of about 60 to 150 nm, both the sheet resistance and the light transmittance are easily set to the target ranges. Moreover, when the light transmittance of the transparent conductive thin film is about 85% or more, the transparency of the transparent conductive film can be improved. The metal oxide mainly composed of indium oxide includes indium oxide or a main component thereof, specifically, 80% (weight%, the same shall apply hereinafter) or more, further 90 to 95%, tin oxide, cadmium oxide. A compound containing 20% or less, further 5 to 10% of one or more of other metal oxides, and specific examples of this compound include ITO and CdIn ₂ O ₄ . Among the metal oxides mainly composed of indium oxide, ITO, particularly tin in a metal equivalent of 10% or less, preferably 5 to 10% is preferable from the viewpoint of reducing sheet resistance while maintaining high transparency. .

  These transparent electrode layers can be formed not only by PVD and CVD but also by an organic metal pyrolysis method, as in the case of inorganic gas barriers.

  In addition to the gas barrier layer and the transparent conductive layer, a color filter layer using a dye or the like may be provided for the purpose of colorizing the liquid crystal display device.

  Using the transparent conductive film thus obtained as an electrode substrate for a liquid crystal display device, the liquid crystal display device can be assembled by a known method.

  Furthermore, this invention film can be used suitably also as a board | substrate for resistive film type touch panels. An inner-type touch panel such as that disclosed in Japanese Patent Application Laid-Open No. 3-121523 and Monthly Display January 1999, page 67 (published by Techno Times Co., Ltd.) has a film with controlled optical characteristics. There has been an attempt to use bisphenol A type polycarbonate. In the case of such a touch panel, the polarizing plate and the substrate for the touch panel are bonded and used, but the optical characteristics of the substrate change due to the stress caused by the contraction of the polarizing plate, which adversely affects the display image. By using the optical film, a touch panel substrate having stable optical characteristics can be obtained. Further, as seen in Japanese Patent Application Laid-Open No. 10-48625, etc., it is known to use a retardation film and a touch panel in combination. In such a touch panel, it is also useful to use the film of the present invention, and in particular, to use a retardation film as a substrate for a touch panel.

  In the touch panel substrate application, the film of the present invention forms a transparent conductive layer on the surface in the same manner as the liquid crystal display substrate. For the touch panel substrate, it is effective to form a water vapor barrier layer similar to that for the liquid crystal display device, if necessary, in order to prevent undesirable dew condensation in the touch panel. The sheet resistance value of the transparent conductive layer is 200 to 2000 Ω / □, more preferably 300 to 1000 Ω / □. The surface on which the transparent conductive layer is formed can be roughened in advance by coating treatment or wear treatment containing filler to prevent unwanted light interference pattern (Newton ring) due to contact with the opposite surface. It is. In order to improve the light transmittance of the substrate for a touch panel, for the purpose of preventing light reflection at the transparent conductive layer, it is possible to reduce the reflectivity by providing multiple layers having different refractive indexes under the transparent conductive layer. A low refractive index layer mainly composed of silicon oxide is formed below the transparent conductive layer mainly composed of indium oxide, and further, a high refractive index layer mainly composed of titanium or zirconium oxide is formed below the transparent conductive layer. A three-layered thin film provided with is a preferred combination.

EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited to this Example.
Each physical property value of the film was measured as follows.

(1) Thickness:
Five test pieces each in the MD and TD directions were cut out from the film in a size of 10 mm × 150 mm. At a temperature of 20 ° C. ± 2 ° C. and a humidity of 60% ± 5%, five locations of each test piece were measured using a Mitsutoyo Digimatic Indicator, and the average value was taken as the thickness of the film.

(2) Phase difference:
A test specimen of MD was cut out from the film with a size of 50 mm × 150 mm. At a temperature of 20 ° C. ± 2 ° C. and a humidity of 60% ± 5%, an unweighted phase difference value R (0) was measured for each test piece using KOBRA 21-SDH manufactured by Oji Scientific.

(3) Photoelastic coefficient:
About each test piece in the above (2), at a temperature of 20 ° C. ± 2 ° C. and a humidity of 60% ± 5%, a phase difference is applied by applying a weight of 0.5 kg to each test piece using KOBRA 21-SDH manufactured by Oji Scientific. The value R (w) was measured. The photoelastic coefficient was calculated from the following equation. In the formula, D is the thickness of the film measured in the above (1).
Photoelastic coefficient (cm ² /dyne)=((R(w)−R(0))/D)÷(0.5×9.8×10 ⁵ / (50 × 10 ⁻¹ × D)

(4) Glass transition temperature:
A test piece was cut out to about 7 mg from the film, and measured using a Seiko DSC up to 300 ° C. at a temperature rising rate of 20 ° C./min. The glass transition temperature was determined from the change point of the DSC profile.

(5) Total light transmittance and haze:
A test piece having a size of 50 mm × 50 mm was cut out from the film and measured using a turbidimeter 300A manufactured by Nippon Denshoku Industries Co., Ltd. at a temperature of 20 ° C. ± 2 ° C. and a humidity of 60% ± 5%.

Comparative Example 1
A methylene chloride solution (20% by weight) was prepared using a bisphenol A type polycarbonate resin, and a film was prepared by a solution casting method. The Tg of this unstretched film was 150 ° C. This film was uniaxially stretched at 165 ° C. using a stretching machine to obtain a stretched film. The photoelastic coefficient was 90 × 10 ⁻¹³ cm ² / dyne. The retardation of this film was 204 nm. The physical properties of the film are shown in Table 1 .

Comparative Example 2
The following structural formula (3) (x / y = 1: 2)

A methylene chloride solution (25% by weight) of a polycarbonate resin comprising the following was prepared, and a film was produced by a solution casting method. The unstretched film had a Tg of 185 ° C. This film was uniaxially stretched at 200 ° C. using a stretching machine to obtain a stretched film. The photoelastic coefficient was 72 × 10 ⁻¹³ cm ² / dyne, and it was confirmed that the photoelastic coefficient was reduced to 80% with respect to the polycarbonate resin of Comparative Example 1. The retardation of this film was 195 nm.

Comparative Example 3
The following structural formula (4)

A methylene chloride solution (25% by weight) of a polycarbonate resin having a water content was prepared, and a film was produced by a casting method. The unstretched film had a Tg of 230 ° C. This film was uniaxially stretched 10% at 245 ° C. using a stretching machine to obtain a stretched film. The photoelastic coefficient was 54 × 10 ⁻¹³ cm ² / dyne, and it was confirmed that the photoelastic coefficient was reduced to 60% with respect to the polycarbonate resin of Comparative Example 1. The retardation of this film was 201 nm.

Examples 1-3
Low molecular weight polystyrene (number average molecular weight 300) is added to the polycarbonate resin of Comparative Example 2 at 1, 5, and 10% by weight, respectively, to prepare a methylene chloride solution (25% by weight), and the film is formed by a solution casting method. Produced. All films had good total light transmittance and haze and excellent transparency, and it was confirmed that Tg was lower than that of Comparative Example 2. These films were uniaxially stretched by 10% using a stretching machine to obtain stretched films. For any film, it was confirmed that the photoelastic coefficient was lower than that of Comparative Example 2. The physical properties of the obtained film are shown in Table 1 .

Examples 4-6
Low molecular weight polystyrene (number average molecular weight 2000) is added to the polycarbonate resin of Comparative Example 2 at 1, 5, and 10% by weight, respectively, to prepare a methylene chloride solution (25% by weight), and the film is formed by a solution casting method. Produced. All films had good total light transmittance and haze and excellent transparency, and it was confirmed that Tg was lower than that of Comparative Example 2. These films were uniaxially stretched by 10% using a stretching machine to obtain stretched films. For any film, it was confirmed that the photoelastic coefficient was lower than that of Comparative Example 2. The physical properties of the obtained film are shown in Table 1 .

Examples 7-9
Low molecular weight polystyrene (number average molecular weight 4000) is added to the polycarbonate resin of Comparative Example 2 at 1, 5, and 10% by weight, respectively, to prepare a methylene chloride solution (25% by weight), and the film is formed by a solution casting method. Produced. All films had good total light transmittance and haze and excellent transparency, and it was confirmed that Tg was lower than that of Comparative Example 2. These films were uniaxially stretched by 10% using a stretching machine to obtain stretched films. For any film, it was confirmed that the photoelastic coefficient was lower than that of Comparative Example 2. The physical properties of the obtained film are shown in Table 1 .

実施例１０
実施例１で得られた樹脂を用いて連続的な溶剤キャスティング法により位相差９ｎｍ、遅相軸のバラツキが±５°以下のロールフィルムを作成した。更に、フィルム上にアクリル系ＵＶ硬化型ハードコートをコーティングしたのち、２００×６６０ｍｍのターゲットを３台備えたマグネトロンスパッタ装置を用いて、始めにフィルムの片面にガスバリヤー層を成膜し、更に、フィルムの他方の面にガスバリヤー膜、透明導電膜を順次形成した。バリヤー膜用ターゲットとしてＳｉＯ₂、透明導電薄膜用ターゲットとして酸化スズ比１０％のＩＴＯ、スパッタガスとしてバリヤー薄膜はアルゴン流量１００ｓｃｃｍ、酸素１ｓｃｃｍで総ガス圧２.０ｍＴｏｒｒ、ＩＴＯではアルゴン３５０ｓｃｃｍ、酸素３.５ｓｃｃｍ、総ガス圧５ｍＴｏｒｒ、パワー条件としてバリヤー薄膜はＲＦ３ｋＷ（２.２７Ｗ／ｃｍ²）、ＩＴＯはＤＣ５.０Ａ２５０Ｖ（０.９６Ｗ／ｃｍ²）となるようにして成膜を行った。バリヤー薄膜は３分処理し、４５ｎｍ、ＩＴＯは３分処理し、１００ｎｍとなる透明導電フィルムを得た。得られたフィルムは、シート抵抗５０Ω／□、光線透過率８０％、酸素ガスバリヤー性０.５ｃｃ／ｍ²／ｄａｙ、水蒸気バリヤー性０.１ｇ／ｍ²／ｄａｙ、である透明導電フィルムが得られた。更に、この透明導電フィルムを用いて、透明電極層を対向させるように配置し、公知の方法にて液晶表示装置を組み立てた。 Comparative Examples 4 and 5
A low molecular weight polystyrene (number average molecular weight 10,000) was added to the polycarbonate resin of Comparative Example 2 in an amount of 1, 5% by weight, respectively, to prepare a methylene chloride solution (25% by weight), and a film was prepared by a solution casting method. . All films had good total light transmittance and haze and excellent transparency, and it was confirmed that Tg was lower than that of Comparative Example 2 . These films were uniaxially stretched by 10% using a stretching machine to obtain stretched films. For any film, it was confirmed that the photoelastic coefficient was lower than that of Comparative Example 2. The physical properties of the obtained film are shown in Table 1 .

Example 10
Using the resin obtained in Example 1, a roll film having a phase difference of 9 nm and a slow axis variation of ± 5 ° or less was prepared by a continuous solvent casting method. Furthermore, after coating the acrylic UV curable hard coat on the film, a gas barrier layer was first formed on one side of the film using a magnetron sputtering apparatus equipped with three 200 × 660 mm targets. A gas barrier film and a transparent conductive film were sequentially formed on the other surface of the film. SiO ₂ as the target for the barrier film, ITO having a tin oxide ratio of 10% as the target for the transparent conductive thin film, the barrier thin film as the sputtering gas, the argon gas flow rate is 100 sccm, the oxygen gas is 1 sccm, the total gas pressure is 2.0 mTorr, the ITO gas is 350 sccm, the oxygen is 3. The film formation was carried out so that the barrier thin film was RF 3 kW (2.27 W / cm ² ) and ITO was DC 5.0 A 250 V (0.96 W / cm ² ) as the power conditions of 5 sccm, the total gas pressure 5 mTorr. The barrier thin film was treated for 3 minutes, 45 nm, and ITO was treated for 3 minutes to obtain a transparent conductive film having a thickness of 100 nm. The obtained film was a transparent conductive film having a sheet resistance of 50Ω / □, a light transmittance of 80%, an oxygen gas barrier property of 0.5 cc / m ² / day, and a water vapor barrier property of 0.1 g / m ² / day. It was. Furthermore, using this transparent conductive film, it arrange | positioned so that a transparent electrode layer might be opposed, and assembled the liquid crystal display device by the well-known method.

Example 11
The unstretched film obtained in Example 1 was used to coat an acrylic UV curable hard coat on the film, and then an ITO film was formed by DC magnetron sputtering. The film thickness of ITO was about 20 nm, and the sheet resistance was 450 ± 10Ω / □. Silver electrodes are printed on the edges as electrodes on this phase difference plate with a transparent conductive film. Separately prepared 5 mm pitch spacers and transparent conductive glass printed with silver electrodes are insulated around both substrates so that the conductive films face each other. A transparent touch panel was created by applying and bonding a functional adhesive. A touch panel is disposed between the polarizing plate and the liquid crystal cell on the opposite side (observation side) of the TFT color TN liquid crystal display device with a backlight, and the touch panel and the liquid crystal display device are prevented from propagating pressure from the pen to the liquid crystal cell. In the meantime, an adhesive containing a gap agent was applied and adhered to the periphery so that a gap of about 0.5 mm was opened, and a liquid crystal display device with a transparent touch panel was produced.

Claims (6)

An optical film composed of an amorphous thermoplastic resin and a resin composition containing 0.1 to 30% by weight of polystyrene having a number average molecular weight of 200 to 4000 ,
The amorphous thermoplastic resin has the following general formula (3)

(X is 20 mol% or more, y is 80 mol% or less)
An optical film having a photoelastic coefficient of 40 × 10 ⁻¹³ cm ² / dyne or less. A retardation film obtained by stretching the optical film according to claim 1 . A transparent conductive film comprising a transparent electrode layer on at least one surface of the optical film according to claim 1 . A liquid crystal display device using the transparent conductive film according to claim 3 as an electrode substrate. A touch panel using the transparent conductive film according to claim 3 as an electrode substrate. A liquid crystal display device using the retardation film according to claim 2 .