WO2011018993A1

WO2011018993A1 - Resin composition for an optical molded body, and said optical molded body

Info

Publication number: WO2011018993A1
Application number: PCT/JP2010/063366
Authority: WO
Inventors: 幸一小澤; 哲央野口
Original assignee: 電気化学工業株式会社
Priority date: 2009-08-12
Filing date: 2010-08-06
Publication date: 2011-02-17
Also published as: JP2012208136A; TW201120121A

Abstract

Provided is a resin composition for an optical molded body, said resin composition having good transparency, heat resistance, thermal stability, and hue. Also provided is said optical molded body. The provided resin composition contains: (i) 20-50 mass% of a styrene-maleimide copolymer (A) that contains 45-70 mass% of a styrene monomer unit, 30-55 mass% of a maleimide monomer unit, and 0-5 mass% of an unsaturated dicarboxylic anhydride monomer unit; and (ii) 50-80 mass% of a styrene-acrylonitrile copolymer (B) that contains 70-84 mass% of a styrene monomer unit and 16-30 mass% of an acrylonitrile monomer unit. The amount of residual maleimide monomer in the styrene-maleimide copolymer (A) is no more than 300 ppm.

Description

Resin composition for optical molded body and optical molded body thereof

The present invention relates to a resin composition for an optical molded body and an optical molded body thereof.

Optical molded bodies with controlled optical anisotropy are used for liquid crystal display elements, electroluminescence elements, and the like.

There are many types of molded articles for optics. For example, there is an optical film. As one of the optical films, there is a film called a retardation film that plays a role of compensating for a phase difference of liquid crystal of a liquid crystal display or improving a viewing angle.
These technologies include the following.

Japanese Patent Laid-Open No. 2002-040258 JP 2005-29211 A JP 2008-094912 A

The present invention provides a novel resin composition for optical molded bodies and an optical molded body thereof.

The gist of the present invention is as follows.
(1) (i) comprising 45 to 70% by weight of styrene monomer units, 30 to 55% by weight of maleimide monomer units, and 0 to 5% by weight of unsaturated dicarboxylic acid anhydride monomer units, and 20-50% by mass of a styrene-maleimide copolymer (A) having a residual maleimide monomer amount of 300 ppm or less,
(Ii) an optical system comprising 70 to 84% by mass of a styrene monomer unit and 50 to 80% by mass of a styrene-acrylonitrile copolymer (B) containing 16 to 30% by mass of an acrylonitrile monomer unit. Resin composition for molded bodies.
(2) An unsaturated dicarboxylic acid anhydride is added to a mixed liquid in which the styrene-maleimide copolymer (A) is mainly composed of the total amount of the styrene monomer and a part of the charged amount of the unsaturated dicarboxylic acid anhydride. A styrene-unsaturated dicarboxylic acid anhydride copolymer obtained by polymerization while adding the remaining amount of the catalyst dividedly or continuously is obtained by imidizing with a primary amine. (1) The resin composition for optical molded bodies as described.
(3) The resin composition for optical molded articles according to (2), wherein the styrene-unsaturated dicarboxylic acid anhydride copolymer is obtained by solution polymerization in a non-polymerizable solvent.
(4) The resin composition for optical molded bodies according to any one of (1) to (3), wherein the styrene-acrylonitrile copolymer (B) is obtained by bulk polymerization or solution polymerization.
(5) An optical molded body comprising the resin composition for optical molded bodies according to any one of (1) to (4).
(6) The optical molded body according to (5), which is a melt-extruded film.
(7) The optical molded body according to (6), which is a stretched film.
(8) The optical molded body according to (7), which is a retardation film.
Here, the “resin composition for an optical molded body” refers to a composition that can be used for producing a known molded body such as an injection molded body, a sheet, and a film. The method for forming the film is not particularly limited, but a method of melt extrusion using a film extruder is preferred.
The “optical molded body” is a molded body used for optical applications such as a light guide plate, a diffusion sheet, a retardation film, an antireflection film, a polarizer protective film, etc. A film formed by extrusion.

The resin composition for an optical molded body of the present invention is useful for an optical molded body because of good transparency, heat resistance, thermal stability, and hue. In addition, the melt-extruded film comprising the resin composition for an optical molded body of the present invention is useful for an optical film for a thin liquid crystal display element. Particularly, a stretched film exhibits negative orientation birefringence and exhibits retardation. It is useful for retardation films because of its excellent properties.

<Explanation of terms>
In the present specification, the symbol “˜” means “above” and “below”. For example, the description “A to B” means greater than A and less than B.

Embodiments of the present invention will be described below.

<Resin composition for optical molded body>
The present embodiment relates to a resin composition for an optical molded article comprising a styrene-maleimide copolymer (A) and an acrylonitrile-styrene copolymer (B). Hereinafter, the styrene-maleimide copolymer (A) and the acrylonitrile-styrene copolymer (B) will be described in order, and then the resin composition for optical molded products containing these and the optical molded product will be described.

[Styrene-maleimide copolymer (A)]
The styrene-maleimide copolymer (A) includes a styrene monomer and a maleimide monomer, and further includes an unsaturated dicarboxylic acid anhydride monomer and other copolymerizable vinyl monomers. Can optionally be included.

<Styrene monomer>
The styrene monomer is not particularly limited, and any known styrene monomer can be used. From the viewpoint of availability, styrene, α-methylstyrene, o-methylstyrene, m Examples thereof include styrene monomers such as -methylstyrene, p-methylstyrene, t-butylstyrene and chlorostyrene. Among these, styrene is particularly preferable from the viewpoint of compatibility. These styrenic monomers may be a mixture of two or more.

<Maleimide monomer>
The maleimide monomer is not particularly limited, and any known maleimide monomer can be used. However, from the viewpoint of availability, heat-resistance imparting effect, etc., for example, N-methylmaleimide, N-alkylmaleimide such as N-butylmaleimide and N-cyclohexylmaleimide, and N-phenylmaleimide, N-chlorophenylmaleimide, N-methylphenylmaleimide, N-methoxyphenylmaleimide, N-tribromophenylmaleimide and the like N- Examples thereof include maleimide monomers such as arylmaleimide. Among these, N-cyclohexylmaleimide and N-phenylmaleimide are particularly preferable from the viewpoint of heat resistance. These maleimide monomers may be a mixture of two or more.

<Unsaturated dicarboxylic acid anhydride monomer>
Examples of the unsaturated dicarboxylic acid anhydride monomer include anhydrides such as maleic acid, itaconic acid, citraconic acid, and aconitic acid, and particularly from the viewpoint of compatibility with the styrene-acrylonitrile copolymer (B). Maleic anhydride is preferred. These unsaturated dicarboxylic acid anhydride monomers may be a mixture of two or more.

<Other copolymerizable vinyl monomers>
The styrene-maleimide copolymer (A) includes copolymerizable vinyl monomer units such as acrylonitrile, methacrylonitrile, acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, acrylic acid 2 A monomer unit such as ethylhexyl, methacrylic acid, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, and 2-ethylhexyl methacrylate may be contained in the maleimide copolymer (A) if it is less than 5% by mass. Good. If these vinyl monomer units are less than 5% by mass, the effect of the present invention is not impaired.

<Composition ratio of styrene-maleimide copolymer (A)>
The constituent ratio of the styrene-maleimide copolymer (A) is 45 to 70% by mass of styrene monomer units, 30 to 55% by mass of maleimide monomer units, 0 units of unsaturated dicarboxylic anhydride monomer units. To 5% by mass, preferably 50 to 60% by mass of styrene monomer units, 40 to 50% by mass of maleimide monomer units, and 0 to 2.5% by mass of unsaturated dicarboxylic acid anhydride monomer units. %.

If the styrene monomer unit is 45% by mass or more or the maleimide monomer unit is 55% by mass or less, the melt viscosity does not become too high, and the styrene-acrylonitrile copolymer (B ) And the kneadability can be kept good, so that the occurrence of unmelted spots can be suppressed.
If the styrene monomer unit is 70% by mass or less or the maleimide monomer unit is 30% by mass or more, transparency can be sufficiently secured.

The unsaturated dicarboxylic acid anhydride monomer unit is an optional compounding component. By adding an unsaturated dicarboxylic acid anhydride monomer unit to the styrene-maleimide copolymer, compatibility may be improved. If the unsaturated dicarboxylic acid anhydride monomer unit is 5% by mass or less, the thermal stability can be kept good.

The amount of the residual maleimide monomer contained in the styrene-maleimide copolymer (A) is 300 ppm or less, preferably 250 ppm or less, more preferably 200 ppm or less. If the amount of the remaining maleimide monomer is 300 ppm or less, it is preferable because the hue can be maintained satisfactorily.

The amount of the remaining maleimide monomer contained in the styrene-maleimide copolymer (A) was measured under the measurement conditions described below.
Device name: GC-2010 (manufactured by Shimadzu Corporation)
Column: Capillary column DB-5MS (phenyl allene polymer)
Temperature: injection port 280 ° C, detector 280 ° C
Temperature rise analysis is performed at a column temperature of 80 ° C. (initial stage).
(Temperature analysis conditions) 80 ° C .; hold 12 minutes 80 to 280 ° C .; raise temperature at 20 ° C./minute 10 minutes 280 ° C .; hold 10 minutes Detector: FID
Procedure: 0.5 g of sample is dissolved in 5 ml of 1,2-dichloroethane solution (0.014 g / L) containing undecane (internal standard substance). Thereafter, 5 ml of n-hexane is added and shaken with a shaker for 10 to 15 minutes to precipitate. Only the supernatant liquid is injected into the GC with the polymer precipitated and precipitated. A quantitative value is calculated from the peak area of the obtained maleimide monomer using a coefficient determined from an internal standard substance.

<Method for producing styrene-maleimide copolymer (A)>
The polymerization mode of the styrene-maleimide copolymer is not particularly limited, and can be produced by a known method such as solution polymerization or bulk polymerization, but the copolymer composition is more uniform by polymerization while performing addition or the like. From the viewpoint of obtaining a desired styrene-maleimide copolymer, solution polymerization is more preferable. In addition, the solvent used in the solution polymerization of the styrene-maleimide copolymer is preferably non-polymerizable from the viewpoint that by-products are difficult to be formed and that there are few adverse effects. Furthermore, the polymerization process of the styrene-maleimide copolymer may be any of batch polymerization, semi-batch polymerization, and continuous polymerization.

The polymerization method of the styrene-maleimide copolymer is not particularly limited, but is preferably obtained by radical polymerization from the viewpoint that it can be produced with high productivity by a simple process. Further, the polymerization initiator used in the polymerization reaction of the styrene-maleimide copolymer is not particularly limited. However, from the viewpoint of availability, ease of reaction control, etc., for example, azobisiso Known azo compounds such as butyronitrile, azobiscyclohexanecarbonitrile, azobismethylpropionitrile, azobismethylbutyronitrile, benzoyl peroxide, t-butylperoxybenzoate, 1,1-bis (t- Butylperoxy) -3,3,5-trimethylcyclohexane, t-butylperoxyisopropyl monocarbonate, t-butylperoxy-2-ethylhexanoate, di-t-butyl peroxide, dicumyl peroxide, ethyl Known organics such as -3,3-di- (t-butylperoxy) butyrate It can be an oxide. Two or more of these polymerization initiators may be used in combination. Further, from the viewpoint of controlling the polymerization reaction rate and the polymerization rate, those conventionally used in the production of conventional styrene resins, such as azo compounds and organic peroxides having a 10-hour half-life temperature of 70 to 120 ° C., are used. It is preferable to use it.

The amount of these polymerization initiators to be used is not particularly limited, but it is preferably 0.1 to 1.5 parts by weight, more preferably 0.8 to 100 parts by weight of all monomer units. 1 to 1.0 part by mass. The amount of these polymerization initiators used is preferably 0.1 parts by mass or more because a sufficient polymerization rate can be obtained. On the other hand, if the use amount of these polymerization initiators is suppressed to 1.5 parts by mass or less, the polymerization rate can be suppressed, the reaction control becomes easy, and it is easy to obtain the target molecular weight of the styrene-maleimide copolymer. Become.

A chain transfer agent can be used for the production of the styrene-maleimide copolymer. The chain transfer agent to be used is not particularly limited. However, from the viewpoint of availability, molecular weight control, etc., for example, n-dodecyl mercaptan, t-dodecyl mercaptan, 2,4-diphenyl, and the like. A known chain transfer agent such as -4-methyl-1-pentene can be used. The amount of these chain transfer agents to be used is not particularly limited as long as the target molecular weight of the styrene-maleimide copolymer can be obtained, but is 0.1% with respect to 100 parts by mass of all monomer units. It is preferable to use ˜0.8 parts by mass, and more preferably 0.15 to 0.5 parts by mass. If the amount of these chain transfer agents used is 0.1 parts by mass or more and 0.8 parts by mass or less, the target molecular weight of the styrene-maleimide copolymer can be easily obtained.

The kind of the non-polymerizable solvent used in the solution polymerization of the styrene-maleimide copolymer is not particularly limited. For example, from the viewpoint of availability, solubility of the copolymer, acetone, Ketones such as methyl ethyl ketone, methyl isobutyl ketone and acetophenone, ethers such as tetrahydrofuran and 1,4-dioxane, aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene, N, N-dimethylformamide, dimethyl sulfoxide, N- There are solvents such as methyl-2-pyrrolidone, and methyl ethyl ketone and methyl isobutyl ketone are particularly preferred because of the ease of solvent removal during the devolatilization recovery of the styrene-maleimide copolymer.

Here, as a method for introducing the maleimide monomer unit, a method of copolymerizing a maleimide monomer and a styrene monomer (direct method), or an unsaturated dicarboxylic acid anhydride and a styrene monomer Are previously copolymerized, and further, the unsaturated dicarboxylic acid anhydride group is converted into a maleimide monomer unit by reacting the unsaturated dicarboxylic acid anhydride group with a primary amine (post-imidation method). is there. The post-imidization method is preferred because the amount of residual maleimide monomer in the copolymer is reduced.

The primary amine used in the post-imidization method is not particularly limited, but from the viewpoint of availability, for example, methylamine, ethylamine, n-propylamine, iso-propylamine, n -Alkylamines such as butylamine, n-pentylamine, n-hexylamine, n-octylamine, cyclohexylamine, decylamine, and aromatic amines such as chloro or bromo-substituted alkylamine, aniline, toluidine, naphthylamine, etc. Of these, aniline and cyclohexylamine are particularly preferred from the viewpoints of heat resistance, reactivity, and ease of handling. In addition, these primary amines may be used alone or in combination of two or more. The addition amount of these primary amines is not particularly limited, but is preferably 0.7 to 1.1 molar equivalents, more preferably 0.85 to the unsaturated dicarboxylic anhydride group. 1.05 molar equivalent. If the addition amount of these primary amines is 0.7 molar equivalent or 0.85 molar equivalent or more, the unsaturated dicarboxylic acid anhydride monomer unit in the styrene-maleimide copolymer is 10% by mass or less. The thermal stability is maintained well. In addition, 1.1 molar equivalent or 1.05 molar equivalent or less is preferable because the amount of primary amine remaining in the styrene-maleimide copolymer is reduced.

When introducing a maleimide monomer unit by a post-imidation method, in the reaction between a primary amine and an unsaturated dicarboxylic acid anhydride group, particularly in the reaction for converting an unsaturated dicarboxylic acid anhydride group to a maleimide group, A catalyst can be used as needed for the purpose of improving the reaction. Although the kind of catalyst is not specifically limited, For example, a tertiary amine can be used. The tertiary amine is not particularly limited, and examples thereof include trimethylamine, triethylamine, tripropylamine, tributylamine, N, N-dimethylaniline, N, N-diethylaniline and the like.

The addition amount of the tertiary amine is not particularly limited, but is preferably 0.01 molar equivalent or more with respect to the unsaturated dicarboxylic acid anhydride group from the viewpoint of improving productivity.

The temperature of the imidization reaction in this embodiment is preferably 100 to 250 ° C., more preferably 120 to 200 ° C. If the temperature of this imidation reaction is 100 ° C. or higher, the reaction rate is improved, so that it does not take a long time to complete the reaction, which is preferable from the viewpoint of productivity. On the other hand, when the temperature of the imidization reaction is suppressed to 250 ° C. or lower, it is preferable because the physical properties of the styrene-maleimide copolymer are hardly deteriorated due to thermal deterioration.

When polymerizing by the post-imidization method, the unsaturated dicarboxylic acid anhydride and the styrenic monomer can be charged in the initial stage of polymerization to polymerize, but the unsaturated dicarboxylic acid anhydride and the styrenic monomer are Since the alternating copolymerization is strong, an alternating copolymer having a composition in which the molar ratio of the unsaturated dicarboxylic acid anhydride to the styrene monomer is 1: 1 is formed at the initial stage of polymerization. In order to obtain the desired structural unit of the styrene-maleimide copolymer, it is necessary to charge the styrene monomer at a higher molar ratio than the unsaturated dicarboxylic acid anhydride. In the latter stage of polymerization, a copolymer having a large amount of styrene monomer units is likely to be formed, and as a result, the composition distribution becomes large. In order to obtain a copolymer with a small composition distribution, a part of the total amount of styrene monomer and unsaturated dicarboxylic acid anhydride is charged at the beginning of polymerization, and the remainder of the unsaturated dicarboxylic acid anhydride is divided. Alternatively, it is preferable to perform polymerization while continuously adding. The ratio of the amount of the unsaturated dicarboxylic acid anhydride charged in the initial stage of polymerization and the amount added in portions or continuously is preferably 5/95 to 50/50, more preferably 10/90 to 25/75. If the ratio of the amount of the unsaturated dicarboxylic acid anhydride charged in the initial stage of polymerization and the amount of divided or continuously added is within these ranges, a styrene-maleimide copolymer having a small composition distribution can be obtained.

The polymerization reaction rate and polymerization rate can be controlled by the polymerization temperature, polymerization time, amount of polymerization initiator, monomer addition rate, and the like. Since the amount of the remaining maleimide monomer in the styrene-maleimide copolymer is 300 ppm or less, the polymerization rate of the maleimide monomer is 99.9% or more in the direct method, and in the post-imidization method, It is preferable to appropriately adjust the conditions so that the polymerization rate of the saturated dicarboxylic acid anhydride is 99.9% or more. For example, in the case of the post-imidization method, the initial polymerization temperature is preferably from 80 to 110 ° C., and preferably from 110 to 150 ° C. in the latter stage of polymerization in order to improve the polymerization rate. The addition rate of the unsaturated dicarboxylic acid is preferably adjusted so that the addition is completed when the polymerization rate of the styrene monomer reaches 80 to 95%. Furthermore, the polymerization rate of unsaturated dicarboxylic acid anhydride can be made 99.9% or more by adjusting polymerization time and the amount of polymerization initiators. When the amount of residual maleimide monomer in the styrene-maleimide copolymer is 300 ppm or less (corresponding to a polymerization rate of 99.9% or more), a maleimide copolymer excellent in hue is obtained. Moreover, what has a favorable hue is obtained also in the resin composition for optical molded objects obtained by using this.

The method for removing volatile components such as non-polymerizable solvent and unreacted monomer used in the polymerization is not particularly limited, and a known method can be used, but a method that can be adopted on an industrial scale. A method using a vent type screw extruder is preferred. The devolatilization conditions when using a vent type screw type extruder are preferably devolatilization at a resin temperature of 310 to 340 ° C. and a reduced pressure of −92 kPaG or less. By increasing the resin temperature under vacuum and reduced pressure, non-polymerizable solvents and unreacted monomers are likely to volatilize. However, if the resin temperature is kept at 340 ° C or lower, the maleimide copolymer is dissolved by thermal degradation. Achieves the objective of obtaining a styrene-maleimide copolymer that is difficult to polymerize, so that the residual amount of maleimide monomer does not increase easily, has excellent hue, has high heat resistance, and has excellent kneadability. It may not be possible. In addition, about the adjustment method of resin temperature, it can carry out by adjusting the screw rotation speed of an extruder, or cylinder temperature.

Moreover, you may use a radical scavenger for the purpose of suppressing the generation amount of the maleimide monomer by heat deterioration. The radical scavenger is not particularly limited, and examples thereof include antioxidants such as phenol compounds, organic phosphorus compounds, organic sulfur compounds, and amine compounds. These radical scavengers may be used alone or in combination of two or more. These radical scavengers receive a significant thermal history in the process of devolatilizing the volatile components in the styrene-maleimide copolymer with a vent type screw extruder, so that the function as a radical scavenger is maintained. In particular, a compound having heat resistance and heat stability is preferred. For example, a radical scavenger having a 1% heat loss temperature exceeding 300 ° C. is even more preferable. The radical scavenger used in this embodiment is preferably added to the polymerization product after polymerization. If added before or during polymerization, the polymerization rate may decrease.

[Acrylonitrile-styrene copolymer (B)]
The acrylonitrile-styrene copolymer (B) contains an acrylonitrile monomer and a styrene monomer, and can optionally contain other copolymerizable vinyl monomers.

<Acrylonitrile monomer>
The acrylonitrile-based monomer is not particularly limited, and any known acrylonitrile-based monomer can be used, but acrylonitrile, methacrylonitrile, and the like are mentioned from the viewpoint of availability, compatibility, and the like. Among these, acrylonitrile is particularly preferable from the viewpoint of compatibility. These acrylonitrile monomers may be a mixture of two or more.

<Styrene monomer>
The styrene monomer of the styrene-acrylonitrile copolymer (B) is not particularly limited, and any known styrene monomer can be used. -Styrene such as styrene, α-methyl styrene, o-methyl styrene, m-methyl styrene, p-methyl styrene, t-butyl styrene, chlorostyrene, etc. from the viewpoint of compatibility with maleimide copolymer (A) Among them, styrene is particularly preferable from the viewpoint of compatibility. These styrenic monomers may be a mixture of two or more.

<Other copolymerizable vinyl monomers>
The styrene-acrylonitrile copolymer (B) includes copolymerizable vinyl monomer units such as acrylic acid, methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, methacrylic acid, If the monomer unit such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, maleic anhydride is less than 5% by mass with respect to the styrene-acrylonitrile copolymer (B) You may contain. If these vinyl monomer units are less than 5% by mass, the effect of the present invention is not impaired.

<Composition ratio of styrene-acrylonitrile copolymer (B)>
The composition ratio of the styrene-acrylonitrile copolymer (B) is 70 to 84% by mass of styrene monomer units and 16 to 30% by mass of acrylonitrile monomer units, preferably 72 to 82% by mass of styrene monomers. And 18 to 28% by mass of acrylonitrile monomer.

If the styrene monomer unit is 70% by mass or more or the acrylonitrile monomer unit is 30% by mass or less, a sufficient hue can be secured.
If the styrene monomer unit is 84% by mass or less or the acrylonitrile monomer unit is 16% by mass or more, the transparency of the optical molded article can be sufficiently secured.

<Method for producing styrene-acrylonitrile copolymer (B)>
As a method for producing the styrene-acrylonitrile copolymer (B), a known method can be adopted, for example, a monomer comprising a styrene monomer, an acrylonitrile monomer and a copolymerizable vinyl monomer. The method of copolymerizing a mixture is mentioned. As the polymerization mode, a known polymerization method can be used. Of these, bulk polymerization or solution polymerization is preferable from the viewpoint of transparency of the optical molded body, and bulk polymerization is more preferable.

[Resin composition for optical molded body]
The resin composition for optical moldings comprises 20-50% by mass of a styrene-maleimide copolymer (A) and 50-80% by mass of a styrene-acrylonitrile copolymer (B), preferably a styrene-maleimide copolymer. (A) 25-45% by mass and styrene-acrylonitrile copolymer (B) 55-75% by mass, more preferably 27.5-40% by mass, styrene-maleimide copolymer (A), styrene-acrylonitrile The copolymer (B) is 60 to 72.5% by mass. Good physical properties can be obtained within this range.
If the styrene-maleimide copolymer (A) is 20% by mass or more and the styrene-acrylonitrile copolymer (B) is 80% by mass or less, sufficient heat resistance can be secured, and the styrene-maleimide system When the copolymer (A) is 50% by mass or less and the styrene-acrylonitrile copolymer (B) is 50% by mass or more, sufficient transparency can be secured.

The method for producing the resin composition for optical molded bodies is not particularly limited as long as the styrene-maleimide copolymer (A) and the styrene-acrylonitrile copolymer (B) are uniformly dispersed. These kneading methods can be used. For example, a melt kneading method using a Banbury mixer, a kneader, a single screw or a twin screw extruder, and the like can be mentioned. In order to obtain a particularly beautiful film, a melt kneading method using a twin screw extruder is preferable.

The extrusion method of the styrene-maleimide copolymer (A) and the styrene-acrylonitrile copolymer (B) includes a method of feeding the whole amount, a styrene-maleimide copolymer (A) and a styrene-acrylonitrile copolymer. Examples include a method in which a part of the polymer (B) is fed from the root position of the screw and the rest of the styrene-acrylonitrile copolymer (B) is side-fed from an intermediate position of the screw.

As extrusion conditions for melt kneading using a twin-screw extruder, the resin temperature is preferably 260 to 320 ° C, more preferably 270 to 310 ° C. The resin temperature can be adjusted by adjusting the cylinder temperature, screw rotation speed, and raw material feed amount.

The screw length / cylinder diameter (= L / D) of the twin screw extruder is in the range of 21 to 48. There are no particular restrictions on the screw configuration, but there are kneading disc lights in which multiple paddle type discs are displaced in the right direction and overlapped, kneading disc lefts in which multiple paddle type discs are displaced in the left direction, and paddle type discs. A combination of a plurality of kneading discs such as a kneading disc neutral that is shifted by 90 degrees and overlapped is preferable.

A screen mesh, a sintered filter, a polymer filter or the like having an opening of 50 μm or less can be installed in the die portion at the tip of the extruder for removing foreign matter.

If necessary, the resin composition for optical molded bodies has a heat resistant stabilizer such as a hindered phenol compound, a lactone compound, a phosphorus compound, a sulfur compound, a light resistant stabilizer such as a hindered amine compound, a benzotriazole compound, You may mix | blend additives, such as a lubricant, a plasticizer, a coloring agent, an antistatic agent, and mineral oil. It is preferable that the compounding quantity is less than 1 mass part with respect to 100 mass parts of resin compositions for optical molded objects.

When the resin composition for optical molded bodies is formed into a film, the film exhibits negative orientation birefringence when further stretched and oriented.

The resin composition for an optical molded body can be used in a known molded body such as an injection molded body, a sheet, and a film, and the method for molding the film is not particularly limited, but the method of melt extrusion using a film extruder is preferable.

[Optical molded product]
An optical molded body refers to a molded body, a sheet, or a film used for optical applications, and a melt-extruded film refers to a film formed by melt extrusion.
The film refers to a known optical film such as a retardation film, an antireflection film, and a polarizer protective film.

The film of the present invention can be stretched and oriented by a known method. When the film is made into a film, it is most preferable for use in a retardation film because if the film is further stretched and oriented, negative orientation birefringence occurs.

As mentioned above, although embodiment of this invention was described, these are illustrations of this invention and can also employ | adopt various structures other than the above.

EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to these.

[Experiment A-1]
In an autoclave having a volume of about 25 liters equipped with a stirrer, 65 parts by mass of styrene, 7 parts by mass of maleic anhydride, 0.2 part by mass of 2,4-diphenyl-4-methyl-1-pentene, and 25 parts by mass of methyl ethyl ketone were charged. After replacing the system with nitrogen gas, the temperature was raised to 92 ° C., 28 parts by mass of maleic anhydride and 0.18 parts by mass of t-butylperoxy-2-ethylhexanoate were added to 100 parts by mass of methyl ethyl ketone. The solution dissolved in was continuously added over 7 hours. After the addition, 0.03 part by mass of t-butylperoxy-2-ethylhexanoate was further added, the temperature was raised to 120 ° C., and the mixture was further reacted for 1 hour to obtain a styrene-maleic anhydride copolymer. Thereafter, 32 parts by mass of aniline and 0.6 parts by mass of triethylamine were added to the viscous resin solution and reacted at 140 ° C. for 7 hours. After the completion of the reaction, the imidization reaction solution was charged into a vent type screw extruder to remove volatile components, thereby obtaining a pellet-shaped styrene-maleimide copolymer A-1.

[Experiment A-2]
In an autoclave having a volume of about 25 liters equipped with a stirrer, 60 parts by mass of styrene, 8 parts by mass of maleic anhydride, 0.3 part by mass of 2,4-diphenyl-4-methyl-1-pentene, and 25 parts by mass of methyl ethyl ketone were charged. After replacing the system with nitrogen gas, the temperature was raised to 92 ° C., 32 parts by weight of maleic anhydride and 0.18 parts by weight of t-butylperoxy-2-ethylhexanoate were added to 100 parts by weight of methyl ethyl ketone. The solution dissolved in was continuously added over 9 hours. After the addition, 0.03 parts by mass of t-butylperoxy-2-ethylhexanoate was further added, the temperature was raised to 120 ° C., and the mixture was further reacted for 1.5 hours to obtain a styrene-maleic anhydride copolymer. It was. Thereafter, 37 parts by mass of aniline and 0.6 parts by mass of triethylamine were added to the viscous resin solution and reacted at 140 ° C. for 7 hours. After the completion of the reaction, the imidization reaction liquid was charged into a vent type screw type extruder to remove volatile components, thereby obtaining a pellet-shaped styrene-maleimide copolymer A-2.

[Experiment A-3]
An autoclave having a volume of about 25 liters equipped with a stirrer was charged with 85 parts by mass of styrene, 3 parts by mass of maleic anhydride, 0.3 part by mass of 2,4-diphenyl-4-methyl-1-pentene, and 25 parts by mass of methyl ethyl ketone. After replacing the system with nitrogen gas, the temperature was raised to 92 ° C., 12 parts by weight of maleic anhydride and 0.18 parts by weight of t-butylperoxy-2-ethylhexanoate were added to 100 parts by weight of methyl ethyl ketone. The solution dissolved in the part was continuously added over 7 hours. After the addition, 0.03 part by mass of t-butylperoxy-2-ethylhexanoate was further added, the temperature was raised to 120 ° C., and the mixture was further reacted for 1 hour to obtain a styrene-maleic anhydride copolymer. Thereafter, 13.5 parts by mass of aniline and 0.23 parts by mass of triethylamine were added to the viscous resin solution and reacted at 140 ° C. for 7 hours. After the completion of the reaction, the imidization reaction liquid was charged into a vent type screw type extruder to remove volatile matter, thereby obtaining a pellet-shaped styrene-maleimide copolymer A-3.

[Experiment A-4]
In a 25 liter autoclave equipped with a stirrer, 76 parts by mass of styrene, 6 parts by mass of maleic anhydride, 0.3 part by mass of 2,4-diphenyl-4-methyl-1-pentene and 25 parts by mass of methyl ethyl ketone were charged. After replacing the system with nitrogen gas, the temperature was raised to 92 ° C., 14 parts by weight of maleic anhydride and 0.18 parts by weight of t-butylperoxy-2-ethylhexanoate were added to 100 parts by weight of methyl ethyl ketone. The solution dissolved in the part was continuously added over 7 hours. After the addition, 0.03 part by mass of t-butylperoxy-2-ethylhexanoate was further added, the temperature was raised to 120 ° C., and the mixture was further reacted for 1 hour to obtain a styrene-maleic anhydride copolymer. Thereafter, 21.6 parts by mass of aniline and 0.36 parts by mass of triethylamine were added to the viscous resin liquid and reacted at 140 ° C. for 7 hours. After the completion of the reaction, the imidization reaction liquid was put into a vent type screw type extruder to remove volatile components to obtain a pellet-shaped styrene-maleimide copolymer A-4.

[Experiment A-5]
In a 25 liter autoclave equipped with a stirrer, 37 parts by mass of styrene, 0.2 part by mass of 2,4-diphenyl-4-methyl-1-pentene, and 25 parts by mass of methyl ethyl ketone were charged, and the system was replaced with nitrogen gas. Then, the temperature was raised to 92 ° C., and a solution obtained by dissolving 63 parts by mass of N-phenylmaleimide and 0.18 parts by mass of t-butylperoxy-2-ethylhexanoate in 100 parts of methyl ethyl ketone was added over 10 hours. Added continuously. After the addition, 0.03 part by mass of t-butylperoxy-2-ethylhexanoate was further added, the temperature was raised to 110 ° C., and the reaction was further continued for 4 hours. The resin solution after completion of the reaction was charged into a vent type screw type extruder to remove volatile components, thereby obtaining pellet-shaped styrene-maleimide copolymer A-5.

[Experiment A-6]
An autoclave having a volume of about 25 liters equipped with a stirrer was charged with 51 parts by mass of styrene, 9 parts by mass of acrylonitrile, 0.2 parts by mass of 2,4-diphenyl-4-methyl-1-pentene, and 25 parts by mass of methyl ethyl ketone. Was replaced with nitrogen gas, the temperature was raised to 92 ° C., and 40 parts by mass of N-phenylmaleimide and 0.18 parts by mass of t-butylperoxy-2-ethylhexanoate were dissolved in 100 parts by mass of methyl ethyl ketone. The solution was added continuously over 7 hours. After the addition, 0.03 part by mass of t-butylperoxy-2-ethylhexanoate was further added, the temperature was raised to 120 ° C., and the mixture was further reacted for 1 hour. The resin solution after completion of the reaction was charged into a vent type screw type extruder to remove volatile components, thereby obtaining pellet-shaped styrene-maleimide copolymer A-6.

[Experiment A-7]
In an autoclave having a volume of about 25 liters equipped with a stirrer, 65 parts by mass of styrene, 7 parts by mass of maleic anhydride, 0.2 part by mass of 2,4-diphenyl-4-methyl-1-pentene, and 25 parts by mass of methyl ethyl ketone were charged. After replacing the system with nitrogen gas, the temperature was raised to 92 ° C., 28 parts by mass of maleic anhydride and 0.18 parts by mass of t-butylperoxy-2-ethylhexanoate were added to 100 parts by mass of methyl ethyl ketone. The solution dissolved in was continuously added over 7 hours. After the addition, 0.03 part by mass of t-butylperoxy-2-ethylhexanoate was further added, the temperature was raised to 120 ° C., and the mixture was further reacted for 1 hour to obtain a styrene-maleic anhydride copolymer. Thereafter, 32 parts by mass of cyclohexylamine and 0.6 part by mass of triethylamine were added to the viscous resin solution and reacted at 140 ° C. for 7 hours. After the completion of the reaction, the imidization reaction liquid was charged into a vent type screw type extruder to remove volatile matter, thereby obtaining pellet-shaped styrene-maleimide copolymer A-7.

[Experiment A-8]
An autoclave having a volume of about 25 liters equipped with a stirrer was charged with 60 parts by mass of styrene, 8 parts by mass of maleic anhydride, 0.2 parts by mass of 2,4-diphenyl-4-methyl-1-pentene, and 25 parts by mass of methyl ethyl ketone. After replacing the system with nitrogen gas, the temperature was raised to 92 ° C., 32 parts by weight of maleic anhydride and 0.18 parts by weight of t-butylperoxy-2-ethylhexanoate were added to 100 parts by weight of methyl ethyl ketone. The solution dissolved in was continuously added over 7 hours. After the addition, 0.03 part by mass of t-butylperoxy-2-ethylhexanoate was further added, the temperature was raised to 120 ° C., and the mixture was further reacted for 1 hour to obtain a styrene-maleic anhydride copolymer. Thereafter, 37 parts by mass of aniline and 0.6 parts by mass of triethylamine were added to the viscous resin solution and reacted at 140 ° C. for 7 hours. After the completion of the reaction, the imidization reaction liquid was put into a vent type screw type extruder to remove volatile matter, thereby obtaining pellet-shaped styrene-maleimide copolymer A-8.

[Experiment A-9]
65 parts by mass of styrene, 0.3 part by mass of 2,4-diphenyl-4-methyl-1-pentene and 25 parts by mass of methyl ethyl ketone are charged into an autoclave having a volume of about 25 liters equipped with a stirrer, and the inside of the system is replaced with nitrogen gas. Then, the temperature was raised to 92 ° C., and a solution of 35 parts by weight of maleic anhydride and 0.18 parts by weight of t-butylperoxy-2-ethylhexanoate in 100 parts of methyl ethyl ketone was added over 8 hours. Added continuously. After the addition, 0.03 part by mass of t-butylperoxy-2-ethylhexanoate was further added, the temperature was raised to 120 ° C., and the mixture was further reacted for 1 hour to obtain a styrene-maleic anhydride copolymer. Thereafter, 32 parts by mass of aniline and 0.6 parts by mass of triethylamine were added to the viscous resin solution and reacted at 140 ° C. for 7 hours. After the completion of the reaction, the imidization reaction liquid was put into a vent type screw type extruder, and volatile components were removed to obtain a pellet-shaped styrene-maleimide copolymer A-9.
The analysis results of Experimental Examples A-1 to A-9 are shown in Table 1.

[Experiment B-1]
A complete mixing type reactor having a volume of about 20 liters equipped with a stirrer and a devolatilizing tank equipped with a preheater were connected. A monomer mixture composed of 85 parts by mass of styrene, 15 parts by mass of acrylonitrile, and 15 parts by mass of ethylbenzene was prepared, and 0.015 parts by mass of t-butylperoxyisopropyl monocarbonate and 0.013 parts by mass of n-dodecyl mercaptan. Parts were mixed to obtain a raw material solution. This raw material solution was introduced into a fully mixed reactor controlled at a temperature of 120 ° C. at 5 kg / hour. In addition, the stirring number of the complete mixing type reactor was 180 rpm. Next, the reaction solution was continuously withdrawn from the complete mixing reactor, and the reaction solution was introduced into a devolatilization tank controlled at a temperature of 235 ° C. and a pressure of 1.0 kPa while being heated by a preheater. And other volatiles were removed. The resin liquid was extracted with a gear pump and extruded into a strand shape to obtain a pellet-shaped polymer B-1.

[Experiment B-2]
A complete mixing type reactor having a volume of about 20 liters equipped with a stirrer and a devolatilizing tank equipped with a preheater were connected. A monomer mixture composed of 73.6 parts by mass of styrene, 26.4 parts by mass of acrylonitrile and 20 parts by mass of ethylbenzene was prepared, and 0.015 part by mass of t-butylperoxyisopropyl monocarbonate and n-dodecyl mercaptan were further prepared. 0.013 mass part was mixed and it was set as the raw material solution. This raw material solution was introduced into a fully mixed reactor controlled at a temperature of 120 ° C. at 5 kg / hour. In addition, the stirring number of the complete mixing type reactor was 180 rpm. Next, the reaction solution was continuously withdrawn from the complete mixing reactor, and the reaction solution was introduced into a devolatilization tank controlled at a temperature of 235 ° C. and a pressure of 1.0 kPa while being heated by a preheater. And other volatiles were removed. The resin liquid was extracted with a gear pump and extruded into a strand shape to obtain a pellet-shaped polymer B-2.

[Experiment B-3]
A complete mixing type reactor having a volume of about 20 liters equipped with a stirrer and a devolatilizing tank equipped with a preheater were connected. A monomer mixed solution composed of 69 parts by mass of styrene, 31 parts by mass of acrylonitrile and 18 parts by mass of ethylbenzene was prepared, and 0.015 parts by mass of t-butylperoxyisopropyl monocarbonate and 0.013 parts by mass of n-dodecyl mercaptan. Parts were mixed to obtain a raw material solution. This raw material solution was introduced into a fully mixed reactor controlled at a temperature of 120 ° C. at 5 kg / hour. In addition, the stirring number of the complete mixing type reactor was 180 rpm. Next, the reaction solution was continuously withdrawn from the complete mixing reactor, and the reaction solution was introduced into a devolatilization tank controlled at a temperature of 235 ° C. and a pressure of 1.0 kPa while being heated by a preheater. And other volatiles were removed. The resin liquid was extracted with a gear pump and extruded into a strand shape to obtain a pellet-shaped polymer B-3.

[Experiment B-4]
A complete mixing type reactor having a volume of about 20 liters equipped with a stirrer and a devolatilizing tank equipped with a preheater were connected. A monomer mixture composed of 56.1 parts by weight of styrene, 17.5 parts by weight of α-methylstyrene, 26.4 parts by weight of acrylonitrile, and 18 parts by weight of ethylbenzene was prepared, and t-butylperoxyisopropyl monocarbonate was further prepared. 0.015 part by mass and 0.013 part by mass of n-dodecyl mercaptan were mixed to obtain a raw material solution. This raw material solution was introduced into a fully mixed reactor controlled at a temperature of 120 ° C. at 5 kg / hour. In addition, the stirring number of the complete mixing type reactor was 180 rpm. Next, the reaction solution was continuously withdrawn from the complete mixing reactor, and the reaction solution was introduced into a devolatilization tank controlled at a temperature of 235 ° C. and a pressure of 1.0 kPa while being heated by a preheater. And other volatiles were removed. The resin liquid was extracted with a gear pump and extruded into a strand shape to obtain a pellet-shaped polymer B-4.

[Experiment B-5]
A complete mixing type reactor having a volume of about 20 liters equipped with a stirrer and a devolatilizing tank equipped with a preheater were connected. A monomer mixture composed of 91.8 parts by mass of styrene, 9.2 parts by mass of acrylonitrile, and 18 parts by mass of ethylbenzene was prepared, and 0.015 parts by mass of t-butylperoxyisopropyl monocarbonate and n-dodecyl mercaptan were further prepared. 0.013 mass part was mixed and it was set as the raw material solution. This raw material solution was introduced into a fully mixed reactor controlled at a temperature of 120 ° C. at 5 kg / hour. In addition, the stirring number of the complete mixing type reactor was 180 rpm. Next, the reaction solution was continuously withdrawn from the complete mixing reactor, and the reaction solution was introduced into a devolatilization tank controlled at a temperature of 235 ° C. and a pressure of 1.0 kPa while being heated by a preheater. And other volatiles were removed. The resin liquid was extracted with a gear pump and extruded into a strand shape to obtain a pellet-shaped polymer B-5.

[Experiment B-6]
A complete mixing type reactor having a volume of about 20 liters equipped with a stirrer and a devolatilizing tank equipped with a preheater were connected. A monomer mixture composed of 60.5 parts by mass of styrene, 39.5 parts by mass of acrylonitrile, and 18 parts by mass of ethylbenzene was prepared, and 0.015 parts by mass of t-butylperoxyisopropyl monocarbonate and n-dodecyl mercaptan were further prepared. 0.013 mass part was mixed and it was set as the raw material solution. This raw material solution was introduced into a fully mixed reactor controlled at a temperature of 120 ° C. at 5 kg / hour. In addition, the stirring number of the complete mixing type reactor was 180 rpm. Next, the reaction solution was continuously withdrawn from the complete mixing reactor, and the reaction solution was introduced into a devolatilization tank controlled at a temperature of 235 ° C. and a pressure of 1.0 kPa while being heated by a preheater. And other volatiles were removed. The resin liquid was extracted with a gear pump and extruded into a strand shape to obtain a pellet-shaped polymer B-6.
Table 2 shows the analysis results of Experimental Examples B-1 to B-6.

The measuring method of each analytical value is as follows.
(1) Constituent unit of styrene-maleimide copolymer NMR was measured under the following measurement conditions, and the integrated value of carbonyl carbon of imide group, unreacted dicarboxylic anhydride group, and maleamic acid intermediate of imidation reaction intermediate The structural unit of the styrene-maleimide copolymer was determined from the ratio of the integrated value of the carbonyl carbon of the product.
Device name: AVANCE-300 (manufactured by BRUKER)
Measurement nuclide: C13
Temperature: 110 ° C
Concentration: 10% by mass
Solvent: DMSO-d6
Integration count: 10,000 times

(2) Residual maleimide monomer content Device name: GC-2010 (manufactured by Shimadzu Corporation)
Column: Capillary column DB-5MS (phenyl allene polymer)
Temperature: injection port 280 ° C, detector 280 ° C
Temperature rise analysis is performed at a column temperature of 80 ° C. (initial stage).
(Temperature analysis conditions) 80 ° C .; hold 12 minutes 80 to 280 ° C .; raise temperature at 20 ° C./minute 10 minutes 280 ° C .; hold 10 minutes Detector: FID
Procedure: 0.5 g of sample is dissolved in 5 ml of 1,2-dichloroethane solution (0.014 g / L) containing undecane (internal standard substance). Thereafter, 5 ml of n-hexane is added and shaken with a shaker for 10 to 15 minutes to precipitate. Only the supernatant liquid is injected into the GC with the polymer precipitated and precipitated. A quantitative value is calculated from the peak area of the obtained maleimide monomer using a coefficient determined from an internal standard substance.

(3) Yellowness Device name: SZ-IIΣ80 Colorimetric color difference meter (Nippon Denshoku Co., Ltd.)
Procedure: 1 g of sample is dissolved in 25 ml of tetrahydrofuran. After dissolution, transfer to a square cell for measurement. The color difference was determined by the permeation method using a square cell of the tetrahydrofuran solution as a blank, and the value was defined as yellowness.

(4) Constituent Unit of Styrene-Acrylonitrile Copolymer A constituent unit of acrylonitrile copolymer was determined by the Kjeldahl method described below.
Procedure: Dissolve 0.3 g of sample in 20 ml of sulfuric acid, add 4.5 g and 0.5 g of potassium sulfate and copper sulfate, respectively, and heat decompose at 350-400 ° C. After cooling to room temperature, 40% sodium hydroxide was added, titration was performed with a 1 / 10N sulfuric acid solution, the nitrogen content was calculated, and the structural unit of the styrene-acrylonitrile copolymer was determined.

[Examples 1 to 9 and Comparative Examples 1 to 8]
After mixing the styrene-maleimide copolymer (A) and the styrene-acrylonitrile copolymer (B) produced in the experimental example at a ratio (mass%) shown in Tables 3 to 4, using a Henschel mixer. Using a twin screw extruder (TEM-35B, manufactured by Toshiba Machine Co., Ltd., L / D = 32), the mixture was melt-kneaded and pelletized under the conditions of a cylinder temperature of 260 ° C., a feed rate of 20 kg / hour, and a screw rotation speed of 250 rpm. To obtain a resin composition for optical molded bodies. The resin temperature was in the range of 270 to 310 ° C.

The resin composition for optical molded bodies was extruded on a roll by extruding a film having a thickness of 100 μm at a cylinder temperature of 240 ° C. and a die temperature of 240 ° C. using a film extruder equipped with a T die.
The obtained film was uniaxially stretched 1.8 times at Tg + 20 ° C. using a tenter transverse stretching machine to obtain a stretched optical film. The measurement results of the obtained film are shown in Tables 3 to 4.

The measuring method of each evaluation is as follows.
(1) Hue; YI value Hue; YI value was determined by molding a 2mmt plate molded at a cylinder temperature of 260 ° C and a mold temperature of 60 ° C using an injection molding machine (IS-50EP manufactured by Toshiba Machine Co., Ltd.). Based on K7105, measurement was performed using a color difference meter (Nippon Denshoku Industries Co., Ltd. SZ-IIΣ80). Hue: A sample having a YI value of 12.0 or less was considered acceptable.
(2) Haze (unit:%) of an unstretched film having a thickness of 100 μm was measured using a haze meter (NDH-1001DP type, manufactured by Nippon Denshoku Industries Co., Ltd.) based on haze ASTM D1003. A film having a haze value of 1.0% or less was regarded as acceptable for the transparency of the unstretched film.
(3) Glass transition temperature The glass transition temperature was measured by differential scanning calorimetry (DSC) under the following measurement conditions.
Measuring instrument: Robot DSC6200 (manufactured by Seiko Instruments Inc.)
Rate of temperature increase: 10 ° C./min A glass transition temperature of 110 ° C. or higher was regarded as acceptable for heat resistance.
(4) Melt mass flow rate (MFR)
Based on JIS K7210, melt mass flow rate (MFR) was measured at a temperature of 200 ° C. and a load of 49 N. An MFR of 0.1-3 (g / 10 min) was considered acceptable for fluidity.
(5) Retardation of retardation of the stretched film (hereinafter “Re”, unit: μm) was measured using a phase difference measuring device (KOBRA-WR manufactured by Oji Scientific Co., Ltd.), and 300 nm or more was regarded as acceptable. Moreover, by observing with a phase-contrast microscope, it confirmed that the sign of orientation birefringence was negative in all the samples in an Example and a comparative example.

<Consideration of results>
From the results of Tables 3 and 4 above, the following can be understood.
That is, the resin compositions for optical molded bodies of Examples 1 to 9 have a hue; small YI value and excellent hue because the amount of residual maleimide monomer in the styrene-maleimide copolymer is 300 ppm or less. An optical molded body.
Furthermore, since it is excellent in transparency and heat resistance, has good retardation development, and exhibits negative orientation birefringence, it can be seen that the retardation film has optimum characteristics.

On the other hand, the resin compositions for optical molded bodies of Comparative Examples 1 to 8 did not show good values as optical films in any of hue, transparency and heat resistance.

In the above, this invention was demonstrated based on the Example. It should be understood by those skilled in the art that this embodiment is merely an example, and that various modifications are possible and that such modifications are also within the scope of the present invention.

The resin composition for an optical molded body and the optical molded body of the present invention have good hue, transparency and heat resistance, and are useful for optical films for thin liquid crystal display elements, in particular, stretched and oriented films. Is negatively oriented birefringence and is useful for retardation films.

Claims

(I) 45 to 70% by mass of a styrene monomer unit, 30 to 55% by mass of a maleimide monomer unit, and 0 to 5% by mass of an unsaturated dicarboxylic acid anhydride monomer unit, and a residual maleimide system 20 to 50% by mass of a styrene-maleimide copolymer (A) having a monomer amount of 300 ppm or less,
(Ii) an optical system comprising 70 to 84% by mass of a styrene monomer unit and 50 to 80% by mass of a styrene-acrylonitrile copolymer (B) containing 16 to 30% by mass of an acrylonitrile monomer unit. Resin composition for molded bodies.
Charge amount of unsaturated dicarboxylic acid anhydride to a mixed liquid mainly composed of styrene-maleimide copolymer (A) and a part of the charged amount of unsaturated dicarboxylic acid anhydride. 2. A styrene-unsaturated dicarboxylic acid anhydride copolymer obtained by polymerization while adding the remainder of the monomer separately or continuously, and obtained by imidizing with a primary amine. The resin composition for optical molded bodies as described.
3. The resin composition for an optical molded article according to claim 2, wherein the styrene-unsaturated dicarboxylic acid anhydride copolymer is obtained by solution polymerization in a non-polymerizable solvent.
The resin composition for an optical molded article according to any one of claims 1 to 3, wherein the styrene-acrylonitrile copolymer (B) is obtained by bulk polymerization or solution polymerization.
An optical molded body comprising the resin composition for optical molded bodies according to any one of claims 1 to 4.
6. The optical molded body according to claim 5, which is a melt-extruded film.
It is a stretched film, The optical molded object of Claim 6 characterized by the above-mentioned.
The optical molded body according to claim 7, which is a retardation film.