JP2001139678A - Modified polycarbonate resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide modified polycarbonate resin films suitable as optical film materials having excellent transparency, photoelastic properties, and fabricability. SOLUTION: Modified polycarbonate resin films are obtained by melt kneading a mixture comprising a cylcoalkylene group-containing polycarbonate resin, an aromatic vinyl monomer, and a radical polymerization initiator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a modified polycarbonate resin film particularly suitable as an optical film material having excellent optical characteristics. More specifically, the present invention relates to a modified polycarbonate resin film which is particularly suitable as an optical film having excellent transparency, low photoelastic coefficient, and secondary workability.

[0002]

2. Description of the Related Art In recent years, in a liquid crystal display device, a retardation film has been inserted between a liquid crystal layer substrate and a polarizing plate for the purpose of improving the visibility of an image. Such a retardation film plays a role such as converting elliptically polarized light transmitted through the liquid crystal layer into linearly polarized light in accordance with the set retardation value. In general, a retardation film has properties such as (1) having high transparency, (2) exhibiting moderate refractive index anisotropy, and (3) having moderate heat resistance. Has been requested. From this viewpoint, a uniaxially stretched film of a bisphenol A type polycarbonate resin has been put into practical use as a retardation film.

However, bisphenol A type polycarbonate resin has a relatively large photoelastic coefficient, that is, a large change in birefringence when subjected to a stress load. Therefore, for example, unevenness in bonding when a liquid crystal layer substrate or a polarizing plate is bonded as a retardation film, a difference in thermal expansion between constituent materials due to receiving heat from a backlight or an external environment, and a stress caused by shrinkage of the polarizing film. The unevenness of the phase difference due to the change in the birefringence index due to the influence of tends to occur, and as a result, the color balance and the contrast of the displayed image tend to be reduced.

As a method of compensating for such a disadvantage that the polycarbonate resin has a large photoelastic coefficient, it has been proposed to lower the photoelastic coefficient by mixing a material having a negative intrinsic birefringence such as polystyrene. On the other hand, a polycarbonate resin having a special structure as disclosed in JP-A-2-88634 is known as a material having a relatively small photoelastic coefficient.

[0005]

However, although the photoelastic coefficient can be reduced by mixing a polycarbonate resin and polystyrene, the mixture is required to have a significantly increased haze, which is a measure of turbidity, and to be transparent. A level of transparency that can be practically used in applications, particularly in optical applications, has not been obtained. Also, Japanese Patent Application Laid-Open No. 2-88634
The special structure of the polycarbonate resin has a high Tg (glass transition temperature), which requires a high temperature for film stretching, and requires special processing equipment different from the conventional ones. For example, the secondary workability is not always sufficient.

Accordingly, an object of the present invention is to provide a modified polycarbonate resin composition which solves the above-mentioned problems of the prior art and which is suitable as an optical film material having excellent transparency, photoelasticity and secondary workability. It is to provide a resin film as a constituent component.

[0007]

SUMMARY OF THE INVENTION The present invention provides a modified polycarbonate resin having high light transmittance and low photoelastic coefficient suitable for use as an optical film, and having good secondary workability. As a result of intensive studies on the film, a modified polycarbonate resin film that achieves the intended purpose is obtained by melt-kneading a mixture containing a certain type of polycarbonate resin, an aromatic vinyl monomer, and a radical polymerization initiator. Thus, the present invention has been completed.

That is, the present invention is obtained by melt-kneading a mixture containing (A) a polycarbonate resin containing a cycloalkylene group, (B) an aromatic vinyl monomer, and (C) a radical polymerization initiator. Provided is a resin film containing a modified polycarbonate resin composition as a main component.

According to the present invention, the haze is 0.03% / μm
A resin film containing a modified polycarbonate resin composition having the following excellent transparency as a main component is provided.

In the present invention, the polycarbonate resin (A) containing a cycloalkylene group has a molar ratio X of a component X derived from a cycloalkylene group-containing aromatic dihydric phenol compound to a component Y derived from another aromatic dihydric phenol compound. : Y is preferably in the range of 20:80 to 100: 0.

In the present invention, the aromatic vinyl monomer (B) is styrene, α-methylstyrene and p-methylstyrene.
It is preferably at least one styrene monomer selected from the group consisting of methylstyrene.

Further, in the present invention, the melt kneading is preferably performed using an extruder.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The polycarbonate resin (A) used in the present invention is not particularly limited as long as it contains a cycloalkylene group, but is an aromatic polycarbonate comprising an aromatic dihydric phenol component and a carbonate component. It is preferred that The aromatic polycarbonate can be usually obtained by reacting an aromatic dihydric phenol compound with a carbonate precursor. That is, an aromatic dihydric phenol compound is obtained by a phosgene method in which phosgene is blown in the presence of a caustic alkali and a solvent, or a transesterification method of transesterifying an aromatic dihydric phenol compound with a bisaryl carbonate in the presence of a catalyst. Can be.

The present invention utilizes the fact that the polycarbonate resin (A) reacts with the aromatic vinyl monomer (B) and the radical polymerization initiator (C). Therefore,
As described above, the polycarbonate resin (A) needs to have a structure containing a cycloalkylene group, and all or a part of the aromatic dihydric phenol compound is a cycloalkylene group-containing aromatic dihydric phenol compound. It is preferred that

Specific examples of the cycloalkylene group-containing aromatic dihydric phenol compound include 1,1-bis (4-
(Hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane and the like.

Specific examples of the aromatic dihydric phenol compound other than the above-mentioned cycloalkylene group-containing aromatic dihydric phenol compound include 2,2-bis (4-hydroxyphenyl) propane and 2,2-bis (4-hydroxy −3,5
-Dimethylphenyl) propane, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) butane, 2,2-bis (4-hydroxy −3,5-
Dimethylphenyl) butane, 2,2-bis (4-hydroxy-3,5-dipropylphenyl) propane, 4,
4′-dihydroxytetraphenylmethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane,
9,9-bis (4-hydroxyphenyl) fluorene,
1,3-bis (4-hydroxyphenyl) -5,7-dimethyladamantane is preferred. One or two of these
More than one species can be used with the cycloalkylene group-containing aromatic dihydric phenol compound.

The molar ratio X: Y of the component X derived from the cycloalkylene group-containing aromatic dihydric phenol compound to the component Y derived from the other aromatic dihydric phenol compound in the polycarbonate resin (A) used in the present invention is 20:80. ~ 1
It is preferably in the range of 00: 0. If the proportion of X is smaller than the above range, the modifying effect of the modified polycarbonate resin composition obtained by the present invention tends to be insufficient.

Specific examples of the carbonate precursor include phosphene used in the phosgene method and bisaryl carbonate used in the transesterification method. In the latter specific example, the aromatic dihydric phenol is used. Bischloroformate, diphenyl carbonate, di-
Examples thereof include p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate, and dinaphthyl carbonate. Among them, phosgene and diphenyl carbonate are preferable.

Specific examples of the aromatic vinyl monomer (B) used in the present invention include, for example, styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, β-methylstyrene. , Dimethylstyrene, methylstyrene such as trimethylstyrene;
α-chlorostyrene, β-chlorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene,
Chlorostyrenes such as dichlorostyrene and trichlorostyrene; α-bromostyrene, β-bromostyrene, o-
Bromostyrene such as bromostyrene, m-bromostyrene, p-bromostyrene, dibromostyrene and tribromostyrene; fluorostyrene such as o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, difluorostyrene and trifluorostyrene; o-nitrostyrene, m-nitrostyrene, p-nitrostyrene,
Nitrostyrenes such as dinitrostyrene and trinitrostyrene; o-hydroxystyrene, m-hydroxystyrene, p-hydroxystyrene, dihydroxystyrene,
Vinylphenol such as trihydroxystyrene; divinylbenzene such as o-divinylbenzene, m-divinylbenzene and p-divinylbenzene; divinylbenzene such as o-diisopropenylbenzene, m-diisopropenylbenzene and p-diisopropenylbenzene Isopropenylbenzene and the like. Among them, styrene, α-methylstyrene, and p-methylstyrene are preferable from the viewpoint of easy industrial use. These may be used alone or in combination of two or more.

As the radical polymerization initiator (C) used in the present invention, a peroxide usually used as a radical polymerization initiator can be used.

Specific examples of the radical polymerization initiator (C) include ketone peroxides such as methyl ethyl ketone peroxide and methyl acetoacetate peroxide;
1-bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, n-butyl-4,4-bis (t-butylperoxy) Peroxy ketals such as valerate and 2,2-bis (t-butylperoxy) butane; permethane hydroperoxide, 1,1,3,
Hydroperoxides such as 3-tetramethylbutyl hydroperoxide, diisopropylbenzene hydroperoxide and cumene hydroperoxide; dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane; α, α′-bis (t-butylperoxy-m-isopropyl) benzene, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxide) Dialkyl peroxides such as oxy) -3-hexyne; diacyl peroxides such as benzoyl peroxide; peralkyls such as di (3-methyl-3-methoxybutyl) peroxydicarbonate and di-2-methoxybutylperoxydicarbonate Oxydicarbonate; t-butyl peroxyoctate , T- butyl peroxy isobutyrate, t- butyl peroxy laurate, t- butyl peroxy-3,5,5-trimethyl hexanoate, t- butyl peroxy isopropyl carbonate,
2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxyacetate, t-
Organic peroxides such as peroxyesters such as butylperoxybenzoate and t-butylperoxyisophthalate are exemplified.

Among them, from the viewpoint of the ability to extract hydrogen from a polycarbonate resin, 1,1-bis (t-
Butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, n-butyl-4,4-bis (t-butylperoxy) valerate, 2,2- Peroxy ketals such as bis (t-butylperoxy) butane; dicumyl peroxide, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, α, α′-bis (t-butyl) Peroxy-m-isopropyl) benzene, t-butylcumyl peroxide, di-t-butyl peroxide,
Dialkyl peroxides such as 2,5-dimethyl-2,5-di (t-butylperoxy) -3-hexyne; diacyl peroxides such as benzoyl peroxide; diacyl peroxides such as benzoyl peroxide; t-butyl peroxide Oxyoctate, t-butylperoxyisobutyrate, t-butylperoxylaurate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxyisopropyl carbonate,
2,5-dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxyacetate, t-
Peroxyesters such as butylperoxybenzoate and t-butylperoxyisophthalate are preferred.

According to the present invention, a mixture containing the polycarbonate resin (A), the aromatic vinyl monomer (B) and the radical polymerization initiator (C) is melt-kneaded. In addition to the aromatic vinyl monomer (B), another vinyl monomer copolymerizable with the aromatic vinyl monomer (B) can be further added. Specific examples of such other vinyl monomers include, for example, acrylonitrile, methacrylonitrile, acrylamide,
Methacrylamide, vinyl acetate, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, metal acrylate, metal methacrylate, methyl acrylate, methyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, acrylic acid Examples include acrylates such as stearyl, methacrylates such as methyl methacrylate, ethyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate, and stearyl methacrylate.

The above mixture may further contain, if necessary, an antioxidant, a metal deactivator, a processing stabilizer, an ultraviolet absorber, an ultraviolet stabilizer, as long as the object of the present invention is not impaired.
Fluorescent whitening agents, metal soaps, antacid adsorbents and other stabilizers, chain transfer agents, nucleating agents, lubricants, plasticizers, fillers, reinforcing agents, pigments, dyes, difficult agents, antistatic agents and other additives Can be blended.

In the present invention, the method of melt-kneading is not particularly limited, and the temperature for melt-kneading may be appropriately selected according to the properties of the components to be used.
Performing at 0 to 350 ° C. is preferable in that the resin is sufficiently melted, the desired reforming effect is sufficiently exhibited, and the resin is not easily thermally decomposed.

The aromatic vinyl monomer (B) is melt-kneaded together with the polycarbonate resin (A) and the radical polymerization initiator (C), so that the resulting modified polycarbonate resin composition has various states. Can exist,
The main states are as follows. That is, a state of being bound to the polycarbonate resin (A) as a polymer of several to several tens of mer, a state of being bound to the polycarbonate resin (A) as a monomer, and a state of being mixed as a polymer of several to several tens of mer , In a state of being mixed as a monomer. As a result of such a mixture of various states, the modified polycarbonate resin composition obtained by the present invention can exhibit excellent optical properties, thermal properties, and the like not found in conventional polycarbonate resins. The properties of the modified polycarbonate resin composition can be variously balanced by changing the amount of the vinyl monomer present in each state.

For example, the photoelastic coefficient of the modified polycarbonate resin composition tends to decrease as the amount increases, and the effect of the amount tends to be particularly large. Further, when the amount increases, the Tg of the modified polycarbonate resin composition tends to decrease, and the effect of the amount is particularly large. On the other hand, when the aromatic vinyl monomer (B) is present as a polymer as in and, when the degree of polymerization or the amount of the polymer increases, the haze of the modified polycarbonate resin composition is easily increased. And the effect of the degree of polymerization in particular cases is large. According to the present invention, since the degree of polymerization can be adjusted to the above range without increasing the degree of polymerization, the resulting modified polycarbonate resin composition has a low haze and a high transparency. can do. Further, the present invention provides a polycarbonate resin having a structure containing a cycloalkylene group, so that the reactivity with the aromatic vinyl monomer is high, and the aromatic vinyl monomer mixed unreacted as shown below Can be reduced, and an increase in haze and an undesirable decrease in Tg can be suppressed.

In the optical film, which is a preferred use of the modified polycarbonate resin composition, the haze is preferably about 1% or less. The haze of the film can be reduced by reducing the thickness, but on the other hand, as described below,
It is preferably at least μm. Therefore, the haze range for being useful as an optical film is preferably at most 0.03% / μm or less when expressed by a value obtained by dividing the haze by the thickness. The haze of the modified polycarbonate resin composition obtained in the present invention is 0.03% / μm or less, which can sufficiently satisfy the above requirements.

In the present invention, in order to optimize the amount of the aromatic vinyl monomer (B) in the above-mentioned state and achieve the intended object of the present invention, the aromatic vinyl monomer (B) is It is preferably used at a ratio of 0.1 to 60 parts by weight, particularly preferably 0.1 to 30 parts by weight, based on 100 parts by weight of the polycarbonate resin (A).
If the amount of the aromatic vinyl monomer (B) is less than this range, the effect of modifying the resulting modified polycarbonate resin composition tends to be insufficient. The resulting modified polycarbonate resin composition tends to be heterogeneous.

For the same reason, the amount of the radical polymerization initiator (C) used is preferably 100 parts by weight of the polycarbonate resin (A) from the viewpoint of sufficiently exhibiting the desired modifying effect of the polycarbonate resin. It is preferably used in a proportion of 0.05 to 10 parts by weight, particularly preferably in a proportion of 0.1 to 5 parts by weight.

Further, the other copolymerizable vinyl monomer is
0.1 parts by weight based on 100 parts by weight of the polycarbonate resin (A).
It is preferable to use 1 to 20 parts by weight.

In the present invention, the apparatus used for melt-kneading a mixture containing the polycarbonate resin (A), the aromatic vinyl monomer (B) and the radical polymerization initiator (C) is the same as that of the present invention. Any device can be used as long as it can be heated to a temperature required for melt-kneading the components used for the kneading and can be kneaded while applying an appropriate shearing force, and specifically, a roll, a co-kneader, a Banbury mixer, a Brabender, a single screw extruder , A kneader such as a twin-screw extruder, a horizontal stirrer such as a twin-screw surface renewing machine, a twin-screw multi-disc device, and a vertical stirrer such as a double helical ribbon stirrer. Among them, from the viewpoint of productivity, it is preferable to use an extruder, particularly a twin-screw extruder. Further, by adjusting the temperature and pressure at the time of melt-kneading, the amount of the product derived from the aromatic vinyl monomer (B) in various states as described above contained in the obtained modified polycarbonate resin composition Can be adjusted. In particular, adjusting the content of the unreacted aromatic vinyl monomer (B) is a useful method for adjusting the Tg of the obtained modified polycarbonate resin composition. For this purpose, a vented extruder can be used as a suitable method.

The modified polycarbonate resin composition of the present invention can be easily formed into a film by a casting method or a melt extrusion method from a generally used solution. For example, when a film is to be obtained by using a casting method, the resin composition may be stirred and mixed with a solvent at a predetermined ratio and used as a uniform solution, and when a film is to be obtained by using a melt extrusion method. May be used by melting and mixing the resin composition. However, a high degree of uniformity is often required in optical applications, which are preferable applications of the resin composition. In such a case, it is preferable to use a casting method from a solution. The solvent used is not particularly limited, but haloalkanes such as dichloromethane, chloroform and 1,2-dichloroethane; cyclic ethers such as tetrahydrofuran, 1,3-dioxolan and 1,4-dioxane; methyl ethyl ketone, methyl isobutyl ketone And ketones such as cyclohexanone, and aromatic solvents such as chlorobenzene. Among them, dichloromethane, chloroform, 1,2-dichloroethane, tetrahydrofuran, 1,3-dioxolan, 1,4-dioxane, cyclohexanone, chlorobenzene and the like are preferable from the viewpoint of solubility and stability such as storage of dope. These can be used alone or in combination of two or more.

When the casting method is used, the concentration of the solution is not particularly limited, and is usually 15 to 3 from the viewpoint of facilitating control of the thickness and thickness accuracy of the film according to the application.
It may be about 0% by weight.

The film of the present invention may optionally contain a plasticizer for the purpose of adjusting the Tg, flexibility and processing characteristics of the film.

Specific examples of the plasticizer include phthalic acid esters such as diethyl phthalate and dioctyl phthalate, stilbene, and the like. The content is usually 10% by weight or less, preferably 5% by weight or less of the film.

Further, the film of the present invention may contain, if necessary, an antioxidant, a metal deactivator, a processing stabilizer, an ultraviolet absorber, an ultraviolet stabilizer, a fluorescent brightening agent within a range not to impair the object of the present invention. Contains agents, metal soaps, antacid adsorbents, other stabilizers, chain transfer agents, nucleating agents, lubricants, plasticizers, fillers, reinforcing agents, pigments, dyes, difficult agents, antistatic agents and other additives. be able to.

The thickness of the film can be selected according to the application.
m is preferable, and 50 to 300 μm is more preferable. Within the above-mentioned range, sufficient self-supporting property of the film is obtained, and the range of the retardation that can be imparted when the film is applied as a retardation film is widened, which is preferable.

[0039]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples.
In addition, each characteristic value was measured as follows. <Tg> About 10 mg of the sample was
Measured at a heating rate of 10 ° C./min up to 240 ° C. under a nitrogen stream of 20 ml / min using JIS K7121
Tg was determined in accordance with.

<Total Light Transmittance and Haze> A test piece having a length of 40 mm and a width of 40 mm was cut out from the film, and a temperature of 20 ° C. ± 2 ° C. and a humidity of 6 was measured using a turbidimeter 300A manufactured by Nippon Denshoku Industries Co., Ltd.
Measured at 0% ± 5%.

<Photoelastic coefficient> 150 m length from film
m, a test piece of 10 mm width was cut out and the temperature was 20 ° C ± 2.
The phase difference [n] of each test piece was measured at a measurement wavelength of 515 nm by a rotating analyzer method (Senamont method) using a microscopic polarization spectrophotometer (manufactured by Oak Manufacturing Co., Ltd.) at a temperature of 60 ° C. and a humidity of 60% ± 5%.
m] was measured.

In the measurement of the phase difference, measurement was performed for a case where no load was applied to the test piece and for a case where a load of 4.9 N was applied in the major axis direction of the test piece, and the photoelastic coefficient was calculated according to the following equation. Calculated.

Photoelastic coefficient [m ² / N] = (phase difference under load [nm] −phase difference under no load [nm]) × width of test piece [mm] × 10 ⁻¹² / load [N] Example 1 2,2-bis (4-hydroxyphenyl) propane and 1,1-bis (4-hydroxyphenyl) -3,3
Using 5-trimethylcyclohexane as an aromatic dihydric phenol component, a polycarbonate resin (A-1) was obtained according to a conventional method. When the molar ratio of the copolymer component in the resin was examined by NMR, the ratio of 2,2-bis (4-hydroxyphenyl) propane component to 2,1,1-
The bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane component was 1. Tg is 185
° C.

Polycarbonate resin (A-1) 100
Parts by weight, 15 parts by weight of styrene and 2,5-dimethyl-
2 parts by weight of 2,5-di (t-butylperoxy) hexane was melt-kneaded at a cylinder temperature of 285 ° C. using a vent-type extruder (Tex44 of Japan Steel Works), and the diameter was 4 mm.
After extruding into a rod shape, the mixture was cooled and cut to obtain pellets of the modified polycarbonate resin composition. The Tg of the pellet was 160 ° C. 100 parts by weight of pellets of the modified polycarbonate resin composition were mixed with 300 parts of methylene chloride.
The mixture was stirred and mixed at room temperature for 4 hours to obtain a clear solution. This solution was cast on a glass substrate, left at room temperature for 15 minutes, and then separated from the glass substrate.
Heat in an oven at 80 ° C. for 10 minutes and at 120 ° C. for 20 minutes to obtain a film having a thickness of 75 μm, 1% by weight of residual methylene chloride, and Tg1.
A transparent film at 48 ° C. was obtained.

The resulting film had a total light transmittance and a haze of 91% and 0.3%, respectively, confirming high transparency. Further, the retardation was 10 nm or less, and it was confirmed that the film had a possibility as an optically isotropic non-oriented film.

Further, the film was heated at 165 ° C. for 10%.
When the film was stretched, a uniform stretched and oriented film was easily obtained, and the workability was good. The retardation and the photoelastic coefficient of the obtained alignment film were 170 nm and 3.9, respectively.
× 10 ⁻¹¹ m ² / N, which proved to have useful properties as a retardation film.

Example 2 2,2-bis (4-hydroxyphenyl) propane and 1,1-bis (4-hydroxyphenyl) -3,3,3
Using 5-trimethylcyclohexane as an aromatic dihydric phenol component, 1,2-bis (4-hydroxyphenyl) propane component was added in an amount of 1,1 to 3 mol based on a conventional method.
Tg210 containing 4 mol of -bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane component
° C polycarbonate resin (A-2) was obtained.

A modified polycarbonate resin was used in the same manner as in Example 1 except that the polycarbonate resin (A-2) was used in place of the polycarbonate resin (A-1), and the cylinder temperature of the extruder was changed to 300 ° C. A pellet of the composition was obtained. The Tg of the pellet was 175 ° C. Using the modified polycarbonate resin composition, a thickness of 75 μm, a residual methylene chloride of 1% by weight and a T
g A transparent film having a temperature of 158 ° C was obtained.

The total light transmittance and haze of the obtained film were 91% and 0.3%, respectively, confirming high transparency. Further, the retardation was 10 nm or less, and it was confirmed that the film had a possibility as an optically isotropic non-oriented film. Furthermore, when this film was stretched at 170 ° C. by 10%, a homogeneous stretched and oriented film was easily obtained, and the workability was good. The retardation and the photoelastic coefficient of the obtained alignment film were 190 nm, respectively.
3.7 × 10 ⁻¹¹ m ² / N, which proved to have useful properties as a retardation film.

Example 3 Pellets of a modified polycarbonate resin composition were obtained in the same manner as in Example 2, except that 30 parts by weight of styrene was used instead of 15 parts by weight of styrene. The pellet has a Tg of 16
3 ° C. Using the modified polycarbonate resin composition, a transparent film having a thickness of 75 μm, a residual methylene chloride of 1% by weight, and a Tg of 152 ° C. was obtained in the same manner as in Example 1.

The total light transmittance and haze of the obtained film were 91% and 0.3%, respectively, confirming high transparency. Further, the retardation was 10 nm or less, and it was confirmed that the film had a possibility as an optically isotropic non-oriented film.

Further, this film was heated at 170 ° C. for 10%.
When the film was stretched, a uniform stretched and oriented film was easily obtained, and the workability was good. The retardation and the photoelastic coefficient of the obtained alignment film were 180 nm and 3.5, respectively.
× 10 ⁻¹¹ m ² / N, which proved to have useful properties as a retardation film.

Comparative Example 1 Instead of 100 parts by weight of pellets of the modified polycarbonate resin composition, 2,2
-Polycarbonate resin having bis (4-hydroxyphenyl) propane component (Panelite C1 manufactured by Teijin Chemicals Limited)
400) 75 μm in thickness, 1% by weight of residual methylene chloride, Tg 1
A transparent film at 50 ° C. was obtained.

The obtained film had a total light transmittance and a haze of 91% and 0.2%, respectively.

Although this film was easily stretched, the retardation and the photoelastic coefficient of the stretched oriented film obtained by stretching 10% at 165 ° C. were 200 n each.
m, 6.1 × 10 ⁻¹¹ m ² / N, and it was confirmed that the photoelastic coefficient was high.

Comparative Example 2 Instead of 100 parts by weight of pellets of the modified polycarbonate resin composition, 2,2
-Polycarbonate resin having bis (4-hydroxyphenyl) propane component (Panelite C1 manufactured by Teijin Chemicals Limited)
400) 75 μm in thickness, 1% by weight of residual methylene chloride in the same manner as in Example 1 except that 90 parts by weight and 10 parts by weight of a polystyrene resin having a weight average molecular weight of 200000 were used.
A transparent film having a Tg of 145 ° C. was obtained. The total light transmittance and haze of the obtained film were 91% and 3, respectively.
At 8%, the haze was remarkably high, and it was confirmed that the level was not suitable for optical use.

Comparative Example 3 Polycarbonate resin (A-2) 10 was used instead of 100 parts by weight of pellets of the modified polycarbonate resin composition.
Except that 0 parts by weight were used, a thickness of 75
A transparent film having a μm of 1% by weight of residual methylene chloride and Tg of 195 ° C. was obtained. The total light transmittance and haze of the obtained film were 91% and 0.3%, respectively. Since stretching of this film requires a high temperature,
For 10%. The retardation and the photoelastic coefficient of the obtained stretched oriented film were 180 nm and 4.2 × 10, respectively.
⁻¹¹ m ² / N, and it was confirmed that the photoelastic coefficient was high.

From the above results, the conventional film made of bisphenol A type polycarbonate resin has a high photoelastic coefficient, and the conventional technique of adding polystyrene to lower the photoelastic coefficient causes a significant increase in haze. It is found that the modified polycarbonate resin composition obtained by the present invention can exhibit excellent characteristics in both photoelastic coefficient and haze, and is excellent in secondary workability, while being unsuitable for use.

[0059]

According to the present invention, it is possible to obtain a modified polycarbonate resin composition having excellent optical properties such as transparency and photoelastic properties and excellent secondary workability. A material that can be suitably used for optical applications such as a substrate is provided.

Continued on the front page F term (reference) 4F071 AA22 AA22X AA50 AA50X AA77 AE06 AF30 AF30Y AF31 AH12 BB02 BB06 BC01 BC12 4J029 AA09 AB07 AC01 AC02 AD10 AE03 AE04 BD09A BD09C HA01 HC01 HC02 HC05A HC05B

Claims (5)

[Claims] 1. A modified polycarbonate system obtained by melt-kneading a mixture containing (A) a polycarbonate resin containing a cycloalkylene group, (B) an aromatic vinyl monomer, and (C) a radical polymerization initiator. A resin film containing a resin composition as a main component. 2. The resin film according to claim 1, wherein the haze is 0.03% / μm or less. 3. The molar ratio X: Y of the component X derived from the aromatic dihydric phenol compound containing a cycloalkylene group and the component Y derived from the other aromatic dihydric phenol compound in the polycarbonate resin (A) is 20:80 to 100: The resin film according to claim 1, which is 0. 4. An aromatic vinyl monomer (B) comprising styrene,
The resin film according to any one of claims 1 to 3, wherein the resin film is at least one styrene monomer selected from the group consisting of α-methylstyrene and p-methylstyrene. 5. The resin film according to claim 1, which is melt-kneaded using an extruder.