JPH11166089A - Heat-resistant resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat-resistant resin composition excellent in optical characteristics such as transparency, and moldability, and further heat resistance. SOLUTION: This heat-resistant resin composition contains (1) a maleimide- based copolymer prepared by copolymerizing (A) a monomer of methacrylic esters with (B) a monomer of maleimides and (2) an aromatic vinyl-based (co)polymer obtained by (co)polymerizing a monomeric mixture containing (C) at least 85 wt.% monomer of aromatic vinyls as mutually thermodynamically compatible components.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-resistant resin composition comprising a mixture of a plurality of polymers, which is excellent in appearance such as transparency and heat resistance.

[0002]

2. Description of the Related Art Conventionally, aromatic vinyl resins represented by polystyrene (PS) resins are colorless and transparent and have excellent properties such as resistance to acids and alkalis. Above all, general-purpose polystyrene resin (GPPS) has excellent moldability and low water absorption, so that the molded product after molding has excellent dimensional accuracy. In addition, GPP
S is colorless and its transparency is close to the value of glass, so that it is possible to obtain a molded article having an excellent appearance close to that of glass, and it is also possible to give a clear coloring. Therefore, the appearance of the obtained molded article can be made more beautiful. For this reason, aromatic vinyl resins such as GPPS are suitably used in many fields such as automobile parts, electric equipment parts, decorative resin plates, and miscellaneous goods.

Further, GPPS can improve its impact resistance by compounding rubber. The thus obtained impact-resistant polystyrene resin (HIP
S) is inferior in transparency when compared to GPPS,
Since the impact resistance can be improved as the rubber content increases, it is suitably used in a wide range of fields such as automobile parts and electric equipment parts.

However, the above-mentioned aromatic vinyl resins generally have low heat resistance, and thus have a problem in that they cannot be used, for example, in parts having a temperature of 100 ° C. or higher. .

Therefore, as a method for improving the heat resistance of an aromatic vinyl resin, for example, a method of copolymerizing α-methylstyrene, methyl methacrylate, and maleic anhydride (see Japanese Patent Publication No. 45-31953). )
Also, a method of copolymerizing an aromatic vinyl monomer and a maleimide monomer (see JP-A-61-278509) is known.

Further, the AS resin, which is a copolymer of styrene and acrylonitrile, maintains transparency, which is a characteristic of polystyrene resin, and has improved heat resistance and impact resistance.

As another method for improving the heat resistance of a polystyrene resin, a method of polymer blending a polystyrene resin with another resin is known. For example, polystyrene and polyphenylene ether (PPE)
A polystyrene-based resin having improved heat resistance can be obtained by combining them with each other.

Further, JP-A-63-89554 discloses a thermodynamically compatible polymer mixture of polystyrene and a copolymer containing cyclohexyl methacrylate.

Heretofore, many maleimide-based copolymers obtained by copolymerizing a maleimide monomer and methyl methacrylate have been studied, and they can be molded as they are and used as optical materials, ABS resin, MMA resin, or the like. A heat-resistant composition mixed with a vinyl chloride resin has been developed. However, it was not known at all that the maleimide-based copolymer was compatible with an aromatic vinyl-based polymer containing 85% by weight or more of aromatic vinyl represented by polystyrene.

On the other hand, a resin excellent in transparency and heat resistance obtained by copolymerizing a maleimide monomer and methyl methacrylate, and an optical material comprising the same are also known (Japanese Patent Application Laid-Open No. Sho 61).
JP-95001, JP-A-1-215810,
See JP-A-7-161070). Also, by blending these resins with methyl methacrylate resin,
Attempts have also been made to improve heat resistance (Japanese Patent Laid-Open No. 61-1 / 1986).
No. 62509).

[0011]

However, the methods described in the above publications can improve the heat resistance of the obtained polystyrene resin to some extent, but it is still not enough. There are problems that the stability at high temperatures is insufficient and that the moldability also decreases.

In the above polymer blending method, the heat resistance is improved, but the obtained polystyrene resin is
Coloring due to E occurs. For this reason, there is a problem that the polystyrene resin cannot be used in a field of application of a polystyrene resin which requires colorlessness and transparency, such as an optical application.

Further, the resin composition described in JP-A-63-89554 can provide a resin composition having transparency, but has a problem that heat resistance and heat stability are insufficient.

In addition, the AS resin is excellent in transparency and heat resistance, but has low moldability and, in addition, has a slight water absorption, so that the dimensional accuracy of the molded article using the AS resin is inferior. There is a problem that.

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a heat-resistant resin composition having excellent appearance such as transparency and having excellent heat resistance. .

[0016]

In order to solve the above-mentioned problems, the heat-resistant resin composition of the present invention comprises a methacrylate monomer (A) and a maleimide monomer (B). A maleimide copolymer (1) obtained by polymerization and an aromatic vinyl polymer (2) obtained by polymerizing a monomer mixture containing at least 85% by weight of an aromatic vinyl monomer (C). It is characterized by including. It is preferable that the maleimide-based copolymer (1) and the aromatic vinyl-based polymer (2) are compatible with each other. The methacrylic acid ester monomer (A) desirably includes a methacrylic acid ester monomer having a cyclohexyl group, and particularly preferably includes only a methacrylic acid ester monomer having a cyclohexyl group.

According to the above constitution, the maleimide copolymer (1), in particular, a methacrylate monomer (A) containing a methacrylate monomer having a cyclohexyl group, and a maleimide monomer (A) By using a maleimide-based copolymer (1) obtained by copolymerizing B)
Since the maleimide-based copolymer (1) and the aromatic vinyl-based polymer (2) are thermodynamically compatible with each other, the aromatic vinyl-based polymer (2) has excellent transparency such as high transparency. The maleimide-based copolymer (1) can improve heat resistance while maintaining appearance and moldability.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below. The heat-resistant resin composition of the present invention comprises a maleimide-based copolymer (1) obtained by copolymerizing a methacrylate monomer (A) and a maleimide monomer (B); An aromatic vinyl polymer (2) obtained by polymerizing a monomer mixture containing at least 85% by weight of the monomer (C) is mixed with each other.

The composition of the maleimide-based copolymer (1) is such that the first portion derived from the methacrylate monomer (A) is 10 to 95% by weight, and the maleimide monomer (B)
Is preferably 5 to 90% by weight, more preferably 40 to 95% by weight of the first portion derived from the methacrylate monomer (A), and the maleimide monomer The second portion derived from (B) is 5 to 60% by weight.

The aromatic vinyl polymer (2) is preferably obtained by polymerizing a monomer mixture containing the aromatic vinyl monomer (C) in an amount of 90% by weight or more, and more preferably an aromatic vinyl polymer (C). It is obtained by polymerizing a monomer mixture containing 95% by weight or more of the aromatic vinyl monomer (C), and more preferably a monomer containing 99% by weight or more of the aromatic vinyl monomer (C). It is obtained by polymerizing a monomer mixture. If the proportion of the aromatic vinyl monomer (A) in the monomer mixture is less than 85% by weight, the obtained aromatic vinyl polymer (2) and the maleimide copolymer (1) This is not preferable because the compatibility between the above-mentioned resins decreases and the transparency and mechanical properties of the resulting heat-resistant resin composition decrease.

In order for the heat-resistant resin composition of the present invention to exhibit excellent optical properties such as high total light transmittance, low turbidity (Haze) and low yellowing degree (YI), the above-mentioned copolymer must be used. It is preferable that (1) and the polymer (2) be thermodynamically compatible with each other.

In the present invention, it is confirmed that the copolymer (1) and the polymer (2) are thermodynamically compatible with each other by checking the glass transition point (Tg) of the obtained heat-resistant resin composition. It can be confirmed by measuring. Specifically, in the mixture of each of the two types of copolymers obtained by mixing the copolymer (1) and the polymer (2), the glass transition point measured by a differential scanning calorimeter is 1 The observation of only the points confirms that the two types of copolymers are thermodynamically compatible with each other. Alternatively, it is possible to visually determine that a film or molded article from the mixture has transparency, or to measure optical properties such as total light transmittance and turbidity by a predetermined method, thereby obtaining two types of each. It is confirmed that the copolymers are thermodynamically compatible with each other. 3 obtained by molding the heat resistant resin composition of the present invention
The total light transmittance of a molded article having a thickness of mm is preferably 80% or more, more preferably 85% or more. The turbidity of the molded article is preferably 5 or less, more preferably 3 or less.

In the present invention, the aromatic vinyl monomer (C) used as a raw material of the polymer (2) includes, for example, styrene, α-methylstyrene, paramethylstyrene, vinyltoluene, chlorostyrene and the like. Is mentioned. Among these aromatic vinyl monomers (C), styrene is particularly preferable from the viewpoint of easy availability and compatibility of the copolymer (1) with the polymer (2). As the aromatic vinyl monomer (C) exemplified above, only one kind may be used, or two or more kinds may be appropriately mixed and used.

The maleimide monomer (B) used as a raw material of the copolymer (1) includes, for example, N-cyclohexylmaleimide, N-phenylmaleimide, N-methylmaleimide, N-ethylmaleimide, Examples thereof include N-isopropylmaleimide, Nt-butylmaleimide, N-tribromophenylmaleimide, N-laurylmaleimide, and N-benzylmaleimide.

Among the above-mentioned maleimide monomers (B), N-phenylmaleimide and N-cyclohexylmaleimide are preferred from the viewpoints of transparency, low coloring property and heat resistance of the resulting heat-resistant resin. Cyclohexylmaleimide is particularly preferred. By using N-cyclohexylmaleimide, the composition range in which the copolymer (1) and the polymer (2) are compatible with each other is widened.
The transparency, low coloring property and heat resistance of the obtained heat-resistant resin composition are further improved.

When N-tribromophenylmaleimide is used as a maleimide monomer, flame resistance can be imparted to the resulting heat-resistant resin composition in addition to transparency and heat resistance. As the maleimide monomer (B) exemplified above, only one type may be used, or two or more types may be appropriately mixed and used.

The methacrylic acid ester monomer (A)
Is preferably a methacrylate having any one of an alkyl group having 1 to 18 carbon atoms, a cyclohexyl group, and a benzyl group. As the methacrylate, specifically, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, amyl methacrylate, isoamyl methacrylate, Octyl methacrylate,
Examples thereof include 2-ethylhexyl methacrylate, decyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-phenoxyethyl methacrylate, 3-phenylpropyl methacrylate, and 2-hydroxyethyl methacrylate.

These methacrylates may be used singly or in a combination of two or more. Among them, the copolymer containing cyclohexyl methacrylate may be used. (1) and polymer (2)
Are preferred because they can increase the compatibility with each other.

Further, in the maleimide copolymer (1), the sum of cyclohexyl methacrylate and N-cyclohexylmaleimide is in the range of 30% by weight or more, preferably in the range of 60% by weight or more. Preferably, the content is in the range of 80% by weight or more, which further enhances the compatibility between the copolymer (1) and the polymer (2) and the heat resistance of the obtained heat-resistant resin composition. Is preferred for

In the maleimide-based copolymer (1),
Furthermore, copolymerization with another monomer (D) used as required, that is, the above two monomers (methacrylic acid ester monomer (A) and maleimide monomer (B)) It is possible to use another monomer (D) different from the above two types of monomers.

Examples of such other monomers (D) include unsaturated nitriles; acrylic esters; olefins; dienes; vinyl ethers; vinyl esters; vinyl fluorides; Allyl esters or methacrylic esters of saturated fatty acid monocarboxylic acids such as polyhydric (meth) acrylates; polyarylates; glycidyl compounds; and unsaturated carboxylic acids are particularly preferred.

Examples of the unsaturated nitriles include acrylonitrile, methacrylonitrile, ethacrylonitrile, phenylacrylonitrile and the like. As the acrylate, an acrylate having at least one selected from the group consisting of an alkyl group having 1 to 18 carbon atoms, a cyclohexyl group, and a benzyl group is preferable.

Examples of the above unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and half-ester compounds and anhydrides thereof. As the compounds exemplified as these other monomers (D), only one type may be used, or two or more types may be appropriately mixed and used.

In the present invention, the other monomer (D) contained in all monomer components (hereinafter referred to as all monomer components) used as a raw material of the maleimide-based copolymer (1)
Is not particularly limited as long as the physical properties required for the obtained heat-resistant resin composition are not impaired, but is preferably 30% by weight or less, and more preferably 20% by weight or less. .

The proportion of the maleimide monomer (B) in the total monomer components is preferably in the range of 5% by weight to 90% by weight, more preferably in the range of 10% by weight to 80% by weight. , 20 wt% to 60 wt%. When the proportion of the maleimide monomer (B) is less than 5% by weight, a sufficient effect of improving heat resistance cannot be obtained, which is not preferable. On the other hand, when the proportion of the maleimide monomer (B) exceeds 90% by weight, the mechanical strength and moldability of the obtained copolymer (1) are reduced and the copolymer (1) and the polymer ( Since the compatibility with 2) is reduced, a heat-resistant resin composition excellent in optical properties such as transparency, mechanical strength, and moldability cannot be obtained.

The monomer other than the aromatic vinyl monomer (C) optionally contained in the monomer mixture is not particularly limited. The same monomer as the monomer (D) can be used.

The method for producing each of the copolymer (1) and the polymer (2) is not particularly limited, and examples thereof include bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization. A method can be used. But,
When suspension polymerization or emulsion polymerization is used, if the copolymer (1) and the polymer (2) are melt-mixed, the compatibility of each heat-resistant resin composition may be reduced, which is not preferable.

Specific examples of the solvent used in the above solution polymerization method include, but are not particularly limited to, organic solvents such as toluene, xylene, ethylbenzene, methyl isobutyl ketone, and methyl ethyl ketone. Further, specific examples of the polymerization initiator used in the above polymerization reaction include cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, and t Radical polymerization initiators such as organic peroxides such as -butylperoxyisopropyl carbonate and t-amylperoxy-2-ethylhexanoate; azo compounds such as 2,2-azobisisobutyronitrile; . One type of these polymerization initiators may be used alone, or two or more types may be appropriately used in combination. The amount of the polymerization initiator used is
What is necessary is just to set suitably according to the combination of the monomer used, reaction conditions, etc., and it is not specifically limited.

Further, other production conditions for producing the above-mentioned copolymer (1) and polymer (2), for example, the reaction temperature and the reaction time, are appropriately set according to the kind of the monomer used. What is necessary is just, and it does not specifically limit. In the polymerization reaction, a chain transfer agent such as an alkyl mercaptan or an α-methylstyrene dimer, a hindered amine-based or benzotriazole-based weather resistance stabilizer, a hindered phenol-based antioxidant, Additives such as a molecular weight modifier, a plasticizer, a heat stabilizer, and a light stabilizer may be added.

When solution polymerization is employed as the method for producing the copolymer (1), the method for removing the copolymer (1) from the reaction solution (polymerization liquid) is not particularly limited.
(I) The reaction solution is introduced into a so-called volatile separation / removal device such as a twin-screw extruder equipped with a vent, and the polymer is separated from unreacted monomers and a solvent by removing volatile components from the reaction solution. Method and (ii) a solvent (poor solvent) that does not dissolve the polymer (eg, the aromatic vinyl polymer)
Various methods can be adopted, such as a method in which the above-mentioned polymer is precipitated (precipitated) by adding a reaction solution to the resulting mixture, and the obtained precipitate, that is, the above-mentioned polymer is separated by filtration and dried. Among these methods, the method (i) is preferred because it is simple and industrially advantageous.

The heat-resistant resin composition according to the present invention can be easily obtained by mixing the copolymer (1) and the polymer (2). The mixing ratio (weight ratio) of the copolymer (1) and the polymer (2) in the heat-resistant resin composition is preferably in the range of 1/99 to 99/1,
A range from 5/95 to 95/5 is more preferred.

Further, in the heat-resistant resin composition, the glass transition point (Tg) of the resin composition after mixing the copolymer (1) and the polymer (2) is 110 ° C. or higher, preferably 115 ° C. As described above, the composition of the copolymer (1),
It is desirable to adjust the blending ratio (weight ratio) between the copolymer (1) and the polymer (2).

In the present invention, the method of mixing the copolymer (1) and the polymer (2) is not particularly limited. For example, the copolymer (1) and the polymer (2) may be mixed with an omni mixer or the like. After pre-blending with a mixer, the obtained mixture can be easily obtained by extrusion kneading. The kneader used for the above-mentioned extrusion kneading is not particularly limited. For example, extruders such as a single-screw extruder and a twin-screw extruder; various known kneaders such as a pressure kneader may be used. Can be.

The heat-resistant resin composition of the present invention can be obtained by extrusion molding,
Various shapes can be obtained by using a molding method such as compression molding, blow molding, injection molding, or stretch molding. For example, the heat-resistant resin composition of the present invention comprising the copolymer (1) and the polymer (2) obtained by extrusion kneading is molded using an injection molding machine to obtain a plate-like molded product or the like. Can be obtained.

The above copolymer (1) and polymer (2)
Can be supplied to an extruder, melt-plasticized, and then extruded and stretched from a die or the like to form a film. In this way, it is possible to produce a film having transparency and excellent heat resistance as desired by using the heat-resistant resin composition of the present invention. Further, the heat-resistant resin composition of the present invention may be a laminated film laminated with another resin such as polystyrene.

The heat-resistant resin composition of the present invention may contain, if necessary, a hindered phenol-based, phosphorus-based, sulfur-based antioxidant or stabilizer; a reinforcing material such as glass fiber or carbon fiber; phenyl salicylate. , 2 (2'-hydroxy-
UV absorbers such as 5-methylphenyl) benzotriazole and 2-hydroxybenzophenone; flame retardants such as tris (dibromopropyl) phosphate, triphenylphosphate, triallylphosphate, ethylene tetrabromide, antimony oxide, and zinc borate; anions system,
It may contain an antistatic agent such as a cationic, nonionic or amphoteric surfactant; and a coloring agent such as an inorganic pigment, an organic pigment or a dye.

Further, the heat resistant resin composition of the present invention may contain a rubbery polymer as a third component other than the above-mentioned copolymer (1) and polymer (2). For example,
As the polymer (2), impact-resistant polystyrene (HIPS) containing a polybutadiene rubber may be used. Further, the third component other than the copolymer (1) and the polymer (2) may further include an engineering plastic such as polyphenylene ether.

As described above, the heat-resistant resin composition according to the present invention is excellent in optical properties such as transparency, heat resistance, and moldability. For this reason, the heat-resistant resin composition of the present invention is excellent in dimensional accuracy in a heat-resistant molded article after molding, and is used in an application field where physical properties such as optical properties such as high transparency and heat resistance and moldability are required. It can be suitably used.

The above-mentioned heat-resistant resin composition can be particularly preferably used in a field where both high transparency and excellent heat resistance are required. For example, the heat-resistant resin composition is required to have high dimensional accuracy, transparency, heat resistance, and the like,
It can be suitably used for materials such as optical parts, automobile parts and electric equipment parts.

[0050]

EXAMPLES Examples of the present invention will be described below as Examples, Comparative Examples and Reference Examples. Hereinafter, the present invention will be described more specifically with reference to Examples, Comparative Examples, and Reference Examples, but the present invention is not limited thereto. In each of the following Examples, Comparative Examples and Reference Examples, the description of “parts” indicates “parts by weight”,
The description of “%” indicates “% by weight”.

Example 1 30 parts of methyl methacrylate,
15 parts of cyclohexyl methacrylate, 5 parts of N-cyclohexylmaleimide, 50 parts of toluene, and t-amyl peroxy-2-ethylhexanoate 0.0 as an initiator
After performing solution polymerization using 5 parts, a solution obtained by dissolving a part of the obtained polymerization solution in methyl ethyl ketone was dropped into methanol, and the precipitated white solid was filtered by suction, dried, and dried with a maleimide-based copolymer. The copolymer (1) as the polymer (1)
-1) was obtained. Table 1 shows the composition ratio and the glass transition temperature of this copolymer (1-1).

Subsequently, polystyrene (trade name: Estyrene G-20, manufactured by Nippon Steel Chemical Co., Ltd.) as the polymer (2)
The copolymer (1-1) was dissolved in methyl ethyl ketone at a weight ratio of 1: 1. The solution was added dropwise to methanol, and the precipitated white solid was filtered by suction, dried, and dried. The resin composition (1) was obtained.

The glass transition temperature (Tg) of this heat-resistant resin composition (1) was measured by the following DSC measurement, and only one point of this glass transition temperature was observed. And the polymer (2) were evaluated for compatibility, and the heat resistance of the heat-resistant resin composition was evaluated from specific numerical values of the glass transition temperature. The results are shown in Table 1.

A solution of the above heat-resistant resin composition (1) in methyl ethyl ketone is placed on a glass plate so as to have a uniform thickness, and then dried to form a cast film. Was evaluated for transparency and appearance. Table 1 shows the results.
It was shown to.

In the following table, CHMA is cyclohexyl methacrylate, MMA is methyl methacrylate, CH
MI represents N-cyclohexylmaleimide, PMI represents N-phenylmaleimide, and ST represents styrene. In addition, t-amyl peroxy-2-ethylhexanoate was used as an initiator in the above table.

[0056]

[Table 1]

Glass transition temperature (Tg) The glass transition temperature was measured using a differential scanning calorimeter (trade name: DSC-8203, manufactured by Rigaku Corporation) under a nitrogen gas atmosphere using α-alumina as a reference. It was calculated from the DSC (Differential Scanning Calorimetry) curve measured at a heating rate of 10 ° C./min from normal temperature to 220 ° C. by the midpoint method.

Copolymer Composition The maleimide content was calculated from the nitrogen content in the elemental analysis, and the composition ratio of methyl methacrylate to cyclohexyl methacrylate was determined by ¹ H-NMR using a proton signal indicative of an alkyl ester moiety. It was calculated from the peak area ratio.

[Examples 2 to 8] By changing the amount of each monomer as a charged composition for obtaining the maleimide-based copolymer (1) in the above Example 1 to the charged composition shown in Table 1, The respective maleimide-based copolymers (2) to (8) were prepared, and the respective maleimide-based copolymers (2) to (8) were prepared.
Using (8), each of the heat-resistant resin compositions (2) to (8) was obtained in the same manner as in Example 1. They were measured in the same manner as in Example 1, and the results are shown in Table 1.

[Comparative Examples 1 to 4] The amount of each monomer for obtaining the maleimide-based copolymer (1) in Example 1 was
By replacing the charge composition shown in Table 1, comparative copolymers (1) to (4) were prepared, and the comparative copolymers (1) to (4) were used. Similarly, each comparative resin composition (1) to (4) was obtained. These were measured in the same manner as in Example 1, and the results were shown in Table 1.
Indicated according to

As is clear from the results shown in Table 1, the heat-resistant resin compositions of Examples 1 to 8 were compared with Comparative Example 1
As compared with the resin compositions of Nos. 4 to 4, while maintaining optical properties such as transparency and moldability of the polystyrene resin,
It can be seen that the heat resistance has been improved.

Next, in order to further clarify the compatibility of the heat-resistant resin composition of the present invention, the optical properties of the heat-resistant resin composition were measured and are shown below as reference examples. In addition,
In the following reference examples, the total light transmittance and turbidity (Haze) were used as optical properties, but these were determined by ASTM.
It was measured according to D1003.

Reference Example The polymerization solution obtained in Example 2 was
It is supplied to a vented twin screw extruder of 30 mφ controlled at a cylinder temperature of 240 ° C., evacuated from the vent port, pelletized the extruded strand, and copolymerized as a maleimide copolymer (1). Coalescing (1-2)
I got

Subsequently, 30 parts of the above copolymer (1-2) and 70 parts of polystyrene (trade name: Estyrene G-20, manufactured by Nippon Steel Chemical Co., Ltd.) as the polymer (2) were mixed with an omni mixer. After mixing, the mixture was melt-kneaded using a 30 mmφ twin-screw extruder controlled at a cylinder temperature of 240 ° C. to obtain a heat-resistant resin composition (9) of the present invention.

The heat-resistant resin composition (9) was molded using an injection molding machine controlled at a cylinder temperature of 240 ° C. and a mold temperature of 60 ° C., and a test piece (50) for measuring each physical property (optical property) was obtained. × 50 × 3 mm). This test piece had a total light transmittance of 90.0 and a turbidity (Haze) of 1.8.

Thus, it can be seen that the heat-resistant resin composition of the present invention has high total light transmittance and low turbidity and excellent compatibility with optical properties.

[0067]

As described above, the heat-resistant resin composition of the present invention comprises a maleimide copolymer obtained by copolymerizing a methacrylate monomer (A) and a maleimide monomer (B). It is configured to include a united product (1) and an aromatic vinyl polymer (2) obtained by polymerizing a monomer mixture containing at least 85% by weight of an aromatic vinyl monomer (C).

Therefore, in the above configuration, the maleimide copolymer (1) improves heat resistance and moldability while maintaining the optical properties such as high transparency of the aromatic vinyl polymer (2). And a heat-resistant resin composition having high dimensional accuracy due to low water absorption by the aromatic vinyl polymer (2).

In addition, the maleimide-based copolymer (1)
And the aromatic vinyl polymer (2) are thermodynamically compatible with each other, so that it is possible to provide a heat-resistant resin composition having excellent transparency and more excellent optical properties.

In the above construction, the maleimide copolymer (1) and the aromatic vinyl copolymer are particularly preferred because the methacrylate monomer (A) contains a methacrylate monomer having a cyclohexyl group. The polymer (2) is further compatible with each other, and a heat-resistant resin composition having excellent transparency, low coloring property and heat resistance can be obtained.

As a result, with the above configuration, a heat resistant resin composition having excellent optical properties, heat resistance and moldability can be obtained. Therefore, the heat-resistant resin composition of the present invention requires high dimensional accuracy, transparency, heat resistance, and the like,
It is advantageous in that it can be suitably used as a material such as optical parts, automobile parts, and electric equipment parts.

Claims (3)

[Claims] 1. A maleimide copolymer (1) obtained by copolymerizing a methacrylate monomer (A) and a maleimide monomer (B), and an aromatic vinyl monomer (C) A) an aromatic vinyl polymer (2) obtained by polymerizing a monomer mixture containing at least 85% by weight). 2. The heat-resistant resin composition according to claim 1, wherein the maleimide-based copolymer (1) and the aromatic vinyl-based polymer (2) are compatible with each other. 3. A methacrylic acid ester monomer (A) comprising:
The heat-resistant resin composition according to claim 1, further comprising a methacrylate monomer having a cyclohexyl group.