JP2001139791A - Production of modified polycarbonate resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for the production of a modified polycarbonate resin composition suitable as a material for optical film having excellent transparency, photo-elastic characteristics and fabrication quality. SOLUTION: The objective resin composition is produced by melting and kneading a mixture containing a polycarbonate resin having a Tg of >=170 deg.C, an aromatic vinyl monomer and a radical polymerization initiator.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a modified polycarbonate resin composition particularly suitable as an optical film material having excellent optical characteristics. More specifically, the present invention relates to a method for producing a modified polycarbonate resin composition which is particularly suitable as an optical film material 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 a 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 phase difference unevenness due to the change of the birefringence tends to occur, and as a result, there is a problem that the color balance of the displayed image and the contrast are easily lowered.

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 improve the problems of the prior art and to produce a modified polycarbonate-based resin composition suitable as an optical film material having excellent transparency, photoelasticity and secondary workability. It is to provide a method.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to a polycarbonate resin having a high light transmittance and a low photoelastic coefficient suitable for use as an optical film, and a good secondary workability. As a result of intensive research on the method for improving the quality, a modified polycarbonate resin that achieves the intended purpose by melt-kneading a mixture containing a certain kind of polycarbonate resin, an aromatic vinyl monomer and a radical polymerization initiator The present inventors have found that a composition can be obtained and completed the present invention.

That is, the present invention relates to (A) a Tg of 170 ° C.
A method for producing a modified polycarbonate resin composition, characterized by melt-kneading a mixture containing the above polycarbonate resin, (B) an aromatic vinyl monomer and (C) a radical polymerization initiator.

According to the present invention, the haze is 0.03% / μm
A modified polycarbonate resin composition having the following excellent transparency can be produced.

In the present invention, the polycarbonate resin (A) contains 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-
Bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 4,4′-dihydroxytetraphenylmethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 9,9-bis ( It contains one or more aromatic dihydric phenol components selected from the group consisting of 4-hydroxyphenyl) fluorene and 1,3-bis (4-hydroxyphenyl) -5,7-dimethyladamantane. Preferably, it is at least one aromatic polycarbonate.

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 has a Tg of 170 ° C. or higher, but it comprises an aromatic dihydric phenol component and a carbonate component. Preferably it is polycarbonate. 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.

Specific examples of the aromatic dihydric phenol compound include 2,2-bis (4-hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane and 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, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-
Bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 4,4′-dihydroxytetraphenylmethane, 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 9,9-bis ( 4-hydroxyphenyl) fluorene, 1,3-bis (4-hydroxyphenyl) -5,7-dimethyladamantane and the like. Among them, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 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. These may be used alone or in combination of two or more, but it is necessary to select the type and amount so that the Tg of the obtained polycarbonate resin is 170 ° C. or higher.

Specific examples of the carbonate precursor include bisaryl carbonate used in a transesterification method in addition to phosgene used in a phosgene method. In the latter specific example, the aromatic dihydric phenol is used. Bischloroformate, diphenyl carbonate, di-
p-tolyl carbonate, phenyl-p-tolyl carbonate, di-p-chlorophenyl carbonate, dinaphthyl carbonate and the like. Of these, phosgene and diphenyl carbonate are preferred.

As described above, the polycarbonate resin (A) used in the present invention has a Tg of 170 ° C. or higher. By having such a Tg, the T of the modified polycarbonate resin composition obtained according to the present invention can be improved.
Even if g is lower than the starting polycarbonate resin (A), practically sufficient heat resistance can be obtained. The polycarbonate resin (A) used in the present invention has a temperature of 300 ° C.
It preferably has the following Tg:

Specific examples of the aromatic vinyl monomer (B) used in the present invention include, for example, styrene; o-methylstyrene, m-methylstyrene, p-methylstyrene,
methyl styrene such as α-methyl styrene, β-methyl styrene, dimethyl styrene and trimethyl styrene;
Chlorostyrenes such as chlorostyrene, β-chlorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, dichlorostyrene, and trichlorostyrene; α-bromostyrene, β-bromostyrene, o-bromostyrene, m- Bromostyrene such as bromostyrene, p-bromostyrene, dibromostyrene and tribromostyrene; fluorostyrene such as o-fluorostyrene, m-fluorostyrene, p-fluorostyrene, difluorostyrene and trifluorostyrene; o-nitrostyrene; nitrostyrenes such as m-nitrostyrene, p-nitrostyrene, 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 or an azo compound which is 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;
-Bis (t-butylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, n-butyl-4,4-bis (t
-Butylperoxy) valerate, 2,2-bis (t-
Peroxyketals such as butylperoxy) butane; hydroperoxides such as permethane hydroperoxide, 1,1,3,3-tetramethylbutyl hydroperoxide, diisopropylbenzene hydroperoxide, 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-butylperoxide, 2,5-dimethyl-2,5- Dialkyl peroxides such as di (t-butylperoxy) -3-hexyne; diacyl peroxides such as benzoyl peroxide; di (3-methyl-3-methoxybutyl) peroxydicarbonate, di-2-methoxybutyl peroxide Peroxydicarbonates such as oxydicarbonate; t-butylperoxyoctate, t-butylperoxyisobutyrate, t-butylperoxylaurate, t-butylperoxy-3,5,5-trimethylhexano Eat, t-
Butyl peroxyisopropyl carbonate, 2,5-
Organic peroxides such as peroxyesters such as dimethyl-2,5-di (benzoylperoxy) hexane, t-butylperoxyacetate, t-butylperoxybenzoate, and t-butylperoxyisophthalate. Above all, from the viewpoint of high hydrogen extraction ability,
1,1-bis (t-butylperoxy) -3,3,5-
Such as trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, n-butyl-4,4-bis (t-butylperoxy) valerate, and 2,2-bis (t-butylperoxy) butane; Peroxyketal; 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-
Dialkyl peroxides such as butylperoxy) -3-hexyne; diacyl peroxides such as benzoyl peroxide; diacyl peroxides such as benzoyl peroxide; t-butylperoxyoctate, t-butylperoxyisobutyrate, t -Butylperoxylaurate, t-butylperoxy-3,5,5-trimethylhexanoate, t-butylperoxyisopropyl carbonate, 2,5-dimethyl-2,5-di (benzoylperoxy) hexane, Peroxyesters such as t-butyl peroxyacetate, t-butyl peroxybenzoate and t-butyl peroxyisophthalate 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 with the polycarbonate resin (A) and the radical initiator (C) to be present in various states in the obtained modified polycarbonate resin composition. However, 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 polymer of several to several tens of mer in the composition. There are a mixed state, a state where the monomer is mixed in the composition as it is, and the like. 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. Also,
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 method of 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. Things. In an 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 later, the thickness of the film is preferably 30 μm or more. Therefore, if the range of haze to be useful as an optical film is expressed by a value obtained by dividing the haze by the thickness, at most 0.03% / μ
m or less. The haze of the modified polycarbonate resin composition obtained in the present invention is 0.03% / μ
m or less, and can sufficiently satisfy the above requirement.

In the present invention, in order to achieve the intended object of the present invention by optimizing the amount of the aromatic vinyl monomer (B) in the following conditions, 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) used is less than this range, the desired modifying effect of the resulting modified polycarbonate resin composition tends to be insufficient. In addition, the resulting modified polycarbonate resin composition tends to be non-uniformly modified.

For the same reason, the amount of the radical initiator (C) used is preferably from 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
For 100 parts by weight of the polycarbonate resin (A),
Preferably, it is used in a ratio of 0.1 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 obtained by 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 using a casting method, the resin composition may be used as a uniform solution by stirring and mixing with a solvent at a predetermined ratio,
When a film is to be obtained by a melt extrusion method, the resin composition may be melt-mixed and used. However, a high degree of uniformity is often required in optical applications, which are preferable applications of the resin composition, and 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 the 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 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 range, a sufficient self-supporting property of the film is obtained, and the range of the retardation that can be imparted when the film is to be applied as a retardation film is widened, which is preferable.

[0031]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples.

Each characteristic value was measured as follows.

<Tg> About 10 mg of a sample was subjected to 20 ml /
At a heating rate of 10 ° C./min under a nitrogen flow of JIS
Tg was determined according to K7121.

<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> Length 150 m 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 using a microscopic polarization spectrophotometer manufactured by Oak Manufacturing Co., Ltd. at a measurement wavelength of 515 nm under 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 long 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] × 1
^0-12 / load [N].

Example 1 2,2-bis (4-hydroxyphenyl) propane and 1,1-bis (4-hydroxyphenyl) -3,3,3
Using 5-trimethylcyclohexane as an aromatic dihydric phenol component, a polycarbonate resin (A
-1) was obtained. When the molar ratio of the copolymer component in this resin (A-1) was examined by NMR, the ratio of 2,2-bis (4-hydroxyphenyl) propane component to 2,1,1-bis (4-hydroxy Phenyl) -3,3,5
The trimethylcyclohexane component was 1. The Tg of this resin (A-1) was 185 ° C.

100 parts by weight of the polycarbonate resin (A-1), 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.

300 parts by weight of methylene chloride was added to 100 parts by weight of pellets of the obtained modified polycarbonate resin composition, and the mixture was stirred and mixed at room temperature for 4 hours to obtain a transparent solution. This solution was cast on a glass substrate and kept at room temperature for 15 minutes.
After leaving it for a minute, it was peeled off from the glass substrate, and then heated in an oven at 80 ° C. for 10 minutes and at 120 ° C. for 20 minutes to give a thickness of 75 μm, residual methylene chloride of 1% by weight, and Tg of 148 ° 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.

Further, this 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 composition was prepared 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 set to 300 ° C. A product pellet was obtained. The Tg of the pellet was 175 ° C.

Using the obtained pellets of the modified polycarbonate resin composition, a thickness of 75% was obtained in the same manner as in Example 1.
A transparent film having a thickness of 1 μm, residual methylene chloride of 1% by weight and Tg of 158 ° 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 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 190 nm and 3.7, respectively.
× 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 the amount of styrene was changed from 15 parts by weight to 30 parts by weight. The Tg of the pellet was 163 ° C.

Using the obtained pellets of the modified polycarbonate resin composition, a thickness of 75% was obtained in the same manner as in Example 1.
A transparent film having a μm of 1% by weight of residual methylene chloride and a Tg of 152 ° 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.

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.

Example 4 2,2-bis (4-hydroxyphenyl) propane and 1,1-bis (4-hydroxyphenyl) -1-phenylethane were used as aromatic dihydric phenol components according to a conventional method. Polycarbonate resin (A-3) having a Tg of 175 ° C and containing 4 mol of 1,1-bis (4-hydroxyphenyl) -1-phenylethane component per 1 mol of 2-bis (4-hydroxyphenyl) propane component was used. Obtained.

Pellets of the modified polycarbonate resin composition were obtained in the same manner as in Example 1 except that the polycarbonate resin (A-3) was used instead of the polycarbonate resin (A-1). The Tg of the pellet is 154
° C.

Using the pellets of the modified polycarbonate resin composition thus obtained, a thickness of 75% was obtained in the same manner as in Example 1.
A transparent film having a μm of 1% by weight of residual methylene chloride and a Tg of 143 ° C. was obtained.

The resulting film had a total light transmittance and a haze of 90% and 0.5%, 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 160 ° 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 photoelastic coefficient of the obtained alignment film were 180 nm and 3.8, respectively.
× 10 ⁻¹¹ m ² / N, which proved to have useful properties as a retardation film.

Example 5 2,2-bis (4-hydroxyphenyl) propane and 4,4'-dihydroxytetraphenylmethane were used as aromatic dihydric phenol components according to a conventional method.
A polycarbonate resin (A-4) having a Tg of 189 ° C and containing 4 mol of 4,4'-dihydroxytetraphenylmethane component per 1 mol of -bis (4-hydroxyphenyl) propane component was obtained.

Pellets of the modified polycarbonate resin composition were obtained in the same manner as in Example 1 except that the polycarbonate resin (A-4) was used instead of the polycarbonate resin (A-1). The Tg of the pellet is 160
° C.

Using the obtained pellets of the modified polycarbonate resin composition, a thickness of 75% was obtained in the same manner as in Example 1.
A transparent film having a μm of 1% by weight of residual methylene chloride and a Tg of 150 ° C. was obtained.

The resulting film had a total light transmittance and a haze of 90% and 0.5%, 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 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 photoelastic coefficient of the obtained alignment film were 170 nm and 3.0, 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 (PANLITE C14 manufactured by Teijin Chemicals Limited)
00) Except for using 100 parts by weight, the same procedure as in Example 1 was carried out, and the thickness was 75 μm, the residual methylene chloride was 1% by weight,
A transparent film at 0 ° C. was obtained.

The total light transmittance and haze of the obtained film were 91% and 0.2%, respectively.

Further, this film was easily stretched, but the retardation and the photoelastic coefficient of the stretched oriented film obtained by stretching at 165 ° C. by 10% were each 200 n.
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, 2,2,2 was used as an aromatic dihydric phenol component.
-Polycarbonate resin having bis (4-hydroxyphenyl) propane component (PANLITE C14 manufactured by Teijin Chemicals Limited)
00) A thickness of 75 μm, a residual methylene chloride of 1% by weight, and the same procedure 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 g of 145 ° C. was obtained.

The total light transmittance and haze of the obtained film were 91% and 3.8%, respectively, and the haze was remarkably high, which was confirmed to be levels unsuitable for optical applications.

Comparative Example 3 Polycarbonate resin (A-2) 100 was used in place of 100 parts by weight of pellets of the modified polycarbonate resin composition.
75 μm in thickness in the same manner as in Example 1 except that parts by weight were used.
m, a residual film of 1% by weight of methylene chloride and a Tg of 195 ° C. were obtained.

The total light transmittance and haze of the obtained film were 91% and 0.3%, respectively.

Since the stretching process of this film requires a high temperature, it was stretched at 210 ° C. by 10%. The retardation and the photoelastic coefficient of the obtained stretched oriented film are each 180 n.
m, 4.2 × 10 ⁻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 reduce 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.

[0070]

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.

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 4F070 AA50 AC32 AC76 AE01 AE02 BA02 BA09 EA03 FA03 FA17 FB06 FC05 4J002 BC032 BC082 BC092 CG011 EA036 EK027 EK037 EK047 EK057 EK067 EK077 PC04 BA01 PC04 4J026 AB17 BA05 BB01 DA01 DB05 DB13 FA02 GA02

Claims (5)

[Claims] 1. A modified polycarbonate system comprising melt-kneading a mixture containing (A) a polycarbonate resin having a Tg of 170 ° C. or higher, (B) an aromatic vinyl monomer, and (C) a radical polymerization initiator. A method for producing a resin composition. 2. The method for producing a modified polycarbonate resin composition according to claim 1, wherein the haze of the modified polycarbonate resin composition is 0.03% / μm or less. 3. The polycarbonate resin (A) comprises, as aromatic phenol components, 2,2-bis (4-hydroxyphenyl) propane, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1-bis ( 4-hydroxyphenyl) -3,3,5-trimethylcyclohexane, 4,4′-dihydroxytetraphenylmethane,
Consists of 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 9,9-bis (4-hydroxyphenyl) fluorene and 1,3-bis (4-hydroxyphenyl) -5,7-dimethyladamantane The method for producing a modified polycarbonate resin composition according to claim 1 or 2, wherein the composition is at least one kind of aromatic polycarbonate containing one or more kinds of aromatic dihydric phenol components selected from the group. . 4. The aromatic vinyl monomer (B) is at least one styrene monomer selected from the group consisting of styrene, α-methylstyrene and p-methylstyrene. The method for producing the modified polycarbonate resin composition according to any one of the above. 5. The method for producing a modified polycarbonate resin composition according to claim 1, wherein the mixture is melt-kneaded using an extruder.