JP2787340B2 - Heat resistant thermoplastic resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermoplastic plastic composition having good matte appearance in terms of molded appearance, heat resistance and impact resistance.

[Conventional technology]

BACKGROUND ART Rubber-reinforced thermoplastic resins represented by acrylonitrile-butadiene-styrene copolymer resin (ABS resin) have impact resistance and good moldability, and are therefore used in many fields. In recent years, in the field of automobile interior parts, etc., in order to give a calm luxury feeling and eliminate the danger of driving due to reflection of light, the molded product surface is matte and has heat resistance Is required.

In general, matting methods for thermoplastic resin molded articles include (1)
A method of transferring and molding the surface of a mold using a mold with fine irregularities, (2) a method of applying a matte paint to a molded product, and (3) heat of inorganic fine particles such as talc and mica. There is a method of molding after mixing with a thermoplastic resin, and (4) a method of molding after mixing crosslinked resin fine particles with a thermoplastic resin.

[Problems to be solved by the invention]

In the above method (1), it is necessary to completely adhere the resin to the mold surface, so that the matting state greatly changes depending on the molding conditions, and the mold is severely abraded, and it costs much to repair. In the method (2), the cost of the paint and the process for painting are newly required. The methods (3) and (4) have a problem that a considerable amount of fine particles must be added to the resin in order to obtain good matting, and the impact strength is significantly reduced. Is the current situation.

[Means for solving the problem]

In view of the above problems, the present inventors have conducted intensive studies, and as a result, a rubber-modified thermoplastic resin reinforced by a rubber-like copolymer enlarged to a particle size suitable for expressing impact strength in a specific method Matting by blending a rubber-modified thermoplastic resin and a heat-resistant thermoplastic resin having an unsaturated nitrile-conjugated diene-based rubbery copolymer which is dynamically vulcanized by a specific method as an essential component. It has been found that a thermoplastic resin composition having good heat resistance and excellent heat resistance and impact resistance can be obtained.

The present invention relates to: [I] a conjugated diene-based rubbery copolymer [A] 100 parts by weight of a latex solid content, and 0.1 to 5 parts by weight of an acid group-containing copolymer [B] latex as a solid content. By
The conjugated diene-based rubber-like copolymer [A] latex is enlarged to an average particle diameter of 0.15 to 0.45 μm, and the expanded rubber-like copolymer [C] latex is 45 to 70 parts by weight (solid content). In the presence, 60-90% by weight of the aromatic vinyl compound,
Monomer mixture 55 to 30 consisting of 10 to 40% by weight of an unsaturated nitrile compound and 30 to 0% by weight of a monomer copolymerizable therewith;
Graft copolymer [D] 5 obtained by emulsion polymerization of parts by weight
II40 parts by weight, and (II) a rubber component containing 5 to 40 parts by weight of a rubber component containing at least 10% by weight of an unsaturated nitrile-conjugated diene-based rubbery copolymer and 95 to 60 parts by weight of a thermoplastic resin [E]. 5 to 30 parts by weight of a rubber-modified thermoplastic resin [F] dynamically vulcanized by heating and kneading in the presence of a crosslinking agent, and [III] 90 to 40 parts by weight of a heat-resistant thermoplastic resin [G]. Parts, and the heat-resistant thermoplastic resin [G] is 10 to 40% by weight of acrylonitrile, 85 to 30% by weight of styrene and / or α-methylstyrene, 5 to 40% by weight of a maleimide compound, and is copolymerizable therewith. From 30 to 0% by weight of
Or, heat-resistant thermoplastic resin [G] is acrylonitrile 10
This is a heat-resistant thermoplastic resin composition comprising about 40% by weight, 90-60% by weight of α-methylstyrene, and 30-0% by weight of a monomer copolymerizable therewith.

Examples of the conjugated diene rubber-like copolymer [A] latex used in the present invention include polybutadiene rubber, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer and the like. It is preferable to use polybutadiene rubber latex. The conjugated diene-based rubber-like copolymer [A] latex can be obtained by a known emulsion polymerization method, and its particle size is 0.03 to 0.20 μm, particularly 0.05 to 0.15 μm.
The range of μm is preferred. Outside this range, it is difficult to control the polymerization rate and the polymerization temperature. Alternatively, the desired particle size may not be obtained at the time of enlargement in the subsequent step, and the polymerization system may become unstable, or the impact resistance and appearance of the final composition may be reduced.

Conjugated diene rubber-like copolymer [A] Acid group-containing copolymer [B] used for enlargement of latex is acrylic acid, methacrylic acid, itaconic acid, crotonic acid, fumaric acid, cinnamic acid, sorbic acid And at least one unsaturated acid monomer selected from the group consisting of
40% by weight, at least one alkyl group having 1 to 12 carbon atoms
It is a copolymer consisting of 97 to 35% by weight of various alkyl acrylates and 0 to 40% by weight of other copolymerizable monomers. Examples of other copolymerizable monomers include methacrylates such as methyl methacrylate, styrene derivatives such as styrene and α-methylstyrene, and monomers such as acrylonitrile.

The unsaturated acid monomer is used in an amount of 3 to 40% by weight.
If it is less than 3% by weight, the enlargement ability is small, and if it exceeds 40% by weight, on the contrary, the enlargement ability is too strong and undesirably generates excessive particles exceeding 1 μm.

Further, the optimum content of the unsaturated acid monomer varies depending on the degree of hydrophilicity of the acrylate used, and when the acrylate has high hydrophilicity, the enlargement occurs in a region where the amount of the unsaturated acid monomer is small. On the other hand, while an effect is produced, an increase in the amount of the unsaturated acid monomer is not preferable because the latex state is destroyed.
Conversely, when the acrylate has low hydrophilicity, the effect of the enlargement is small in a region where the amount of the unsaturated acid monomer is low, and the effect is not obtained unless the amount of the unsaturated acid monomer becomes larger than a certain amount. I don't come. For example, methyl acrylate or ethyl acrylate, which is a highly hydrophilic acrylate, is optimal when the amount of the unsaturated acid monomer is 5 to 10% by weight, whereas the alkyl group has 4 or more carbon atoms. In the case of butyl acrylate or 2-ethylhexyl acrylate, which is a hydrophobic alkyl acrylate, the amount of the unsaturated acid monomer is 10 to 20.
It is optimal when it is% by weight.

The acid group-containing copolymer [B] latex used in the present invention can be polymerized by a method of charging the monomer mixture having the above composition at a time or a method of continuously adding the monomer mixture. Further, after polymerizing a portion of the monomer mixture that is 5 to 90% by weight and does not contain the unsaturated acid, 95 to 10% by weight of the remaining monomer containing the unsaturated acid is used. Latexes having a multilayer structure of two or more layers can also be obtained by subsequent polymerization without producing new particles, that is, by two or more stages of polymerization.

The added amount of the acid group-containing copolymer [B] latex is a conjugated diene rubbery copolymer [A] 10
0.1 to 5 parts by weight, preferably 0.5 to 3 parts by weight per 0 parts by weight. If it is less than 0.1 part by weight, it cannot be enlarged to the target particle size, and if it is more than 5 parts by weight, the effect of the enlargement effect is saturated and the area of the enlarged particle diameter decreases from the maximum value. The diameter may become too small or, in some cases, agglomerate during the enlargement operation. When performing the enlargement operation, the pH of the conjugated diene rubbery copolymer [A] latex is preferably 7 or more. When the pH value is on the acidic side, even if the acid group-containing copolymer [B] latex is added, the effect of the enlargement is small, and the desired composition may not be produced advantageously.

The average particle diameter of the enlarged rubber-like copolymer (C) latex obtained by the enlargement operation method is 0.15 to 0.45 μm,
In particular, the range of 0.25 to 0.4 μm is preferable. Outside this range, problems such as poor impact strength development and poor moldability are caused.

In the presence of 45 to 70 parts by weight (in solid content) of an enlarged rubbery copolymer [C] latex, 60 to 90% by weight of an aromatic vinyl compound, 10 to 40% by weight of an unsaturated nitrile compound and copolymerization thereof Monomer mixture consisting of 30 to 0% by weight of possible monomers
The graft copolymer [D] is obtained by emulsion graft polymerization of 55 to 30 parts by weight.

As the aromatic vinyl compound, styrene, α-methylstyrene, o-methylstyrene, p-methylstyrene,
Examples include 2,4-dimethylstyrene, p-tertiary butylstyrene, halogenated styrene, p-ethylstyrene, and a mixture of two or more thereof. Examples of unsaturated nitrile compounds include acrylonitrile, methacrylonitrile, ethacrylonitrile, fumaronitrile, and the like.
Mixtures of more than one species. Further, examples of the copolymerizable monomer include unsaturated carboxylic acid compounds such as methacrylic acid and acrylic acid, unsaturated ester compounds such as methyl methacrylate, butyl acrylate, and vinyl acetate; N-phenylmaleimide; Maleimide compounds such as cyclohexylmaleimide and the like, and mixtures of two or more of these.

The monomer mixture used for emulsion graft polymerization is 55-30
The amount by weight of the enlarged rubbery copolymer [C] is in the range of 45 to 70 parts by weight. When [C] is less than 45 parts by weight, it is necessary to increase the proportion of the graft copolymer [D] in order to increase the impact resistance of the final composition, and as a result, the proportion of the other resin composition is reduced. And the performance such as mattability and heat resistance is reduced. On the other hand, if [C] is more than 70 parts by weight, the resin powder produced by the coagulation performed after the graft polymerization becomes coarse, which causes difficulty in production.

At the time of graft polymerization, it is preferable to add an emulsifier to cause stable polymerization. There is no particular limitation as long as it is an emulsifier used in ordinary emulsion polymerization, and potassium rosinate, potassium oleate, dipotassium alkenylsuccinate, sodium dodecylbenzenesulfonate, and the like, and a mixture thereof are used.

As a rubber component in the rubber-modified thermoplastic resin [F] used in the present invention, an unsaturated nitrile-conjugated diene-based rubbery copolymer is an essential component, and 10 to 50% by weight of unsaturated nitrile and 90% of conjugated diene are used. 〜50% by weight of the copolymer is preferred.
Examples of the unsaturated nitrile include acrylonitrile and methacrylonitrile, and examples of the conjugated diene include 1,3-butadiene, 2,3-dimethylbutadiene, isoprene, and 1,3-pentadiene.

Further, a part of the conjugated diene can be substituted with another copolymerizable monomer such as an aromatic vinyl compound, an unsaturated carboxylic acid compound, and an unsaturated ester compound.

As the other rubber used in combination with the unsaturated nitrile-conjugated diene polymer rubber used in the present invention, a rubber which can be crosslinked with a crosslinking agent commonly used in the rubber industry such as a sulfur vulcanization system or an organic peroxide vulcanization system Conjugated diene-based polymer rubbers such as polybutadiene rubber, styrene-butadiene copolymer rubber (either random or block type), natural rubber, polyisoprene rubber, polychloroprene rubber, and hydrides thereof, EPDM, etc. Is mentioned. Unsaturated nitrile
When the conjugated diene-based polymer rubber is used in combination with the above-mentioned other rubber, the ratio of the unsaturated nitrile-conjugated diene-based polymer rubber in the mixed rubber is at least 10% by weight. Erasability is not improved. It is preferably at least 20% by weight.

The rubber-modified thermoplastic resin [F] of the present invention comprises a rubber component 5
4040 parts by weight and 95-60 parts by weight of the thermoplastic resin [E] are melt-mixed, and then a crosslinking agent of a rubber component is added. Those produced by vulcanization are suitable.

As the thermoplastic resin [E], an acrylonitrile-styrene copolymer, an acrylonitrile-α-methylstyrene copolymer or a copolymer of these copolymers with N-phenylmaleimide or N-cyclohexylmaleimide as a third component was used. And an acrylonitrile-styrene copolymer are preferred.

The vulcanizing agent used in the present invention is not particularly limited as long as the rubber component can be vulcanized. Usually, sulfur and / or a sulfur-donating compound (for example, a thiuram-based compound such as tetramethylthiuram disulfide, tetraethylthiuram disulfide, or a morpholine-based compound such as morpholine disulfide) and zinc oxide, magnesium oxide, and stearin Vulcanization aids such as zinc acid, stearic acid vulcanization accelerators, for example, guanidine compounds such as diphenylguanidine, thiazole compounds such as mercaptobenzothiazole, benzothiazyl disulphide, cyclohexylbenzothiazylsulfenamide ,
Sulfur vulcanization system using thiuram-based compounds such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide, dicumyl peroxide, 2,5-
Dimethyl-2,5-di- (t-butylperoxy) -hexane, 2,5-dimethyl-2,5-di- (t-butylperoxy) -hexyne-3, 1,3-bis (t- An organic peroxide vulcanization system such as butylperoxy-isopropyl) benzene is used.

Conditions such as temperature and time in dynamic vulcanization vary depending on the rubber component, thermoplastic resin, cross-linking agent, etc. used.
The reaction is performed at 0 to 230 ° C for 5 to 10 minutes.

The heat-resistant thermoplastic resin [G] used in the present invention is a graft copolymer [D] and a rubber-modified thermoplastic resin [F].
10 to 40% by weight of acrylonitrile, 85 to 30% by weight of styrene and / or α-methylstyrene, 5 to 40% by weight of a maleimide compound, and 30 to 10% by weight of a monomer copolymerizable therewith % Or acrylonitrile 10 to 40% by weight, α-methylstyrene 85 to 30%
% By weight, and 30 to 0% by weight of a monomer copolymerizable therewith
Is a copolymer consisting of More preferably, the composition distribution of these copolymers should be as narrow as possible. In such a case, it is advantageous in terms of the impact strength. When a maleimide compound or a copolymer containing α-methylstyrene as an essential component is used, a thermoplastic resin not containing these components such as an acrylonitrile-styrene copolymer (AS resin) is used. The matting level developed by adding an amount of the rubber-modified thermoplastic resin (F) is increased. However, when using a maleimide-based or α-methylstyrene-based copolymer, both may be used in combination, or a part of an AS resin or a polycarbonate resin may be used for the purpose of improving physical properties such as moldability and impact strength of the final composition. ,
It may be used by replacing it with a thermoplastic resin such as PMMA resin.

Examples of the maleimide compound include maleimide, N-alkylmaleimides in which hydrogen bonded to a nitrogen atom of maleimide is substituted with an alkyl group having 1 to 12 carbon atoms, hydrogen of benzene nucleus of N-phenylmaleimide and N-phenylmaleimide. Is at least one of an alkyl group having 1 to 6 carbon atoms, a halogen, an alkoxy group having 1 to 4 carbon atoms, a phenyl group, a carboxyl group, a nitro group, an amino group, and a hydroxyl group. Substituted N-phenylmaleimide derivatives and the like, and one or more maleimide compounds can be used. It is preferable to use N-phenylmaleimide and N-cyclohexylmaleimide.

Further, as the copolymerizable monomer, methacrylic acid,
Unsaturated carboxylic acid compounds such as acrylic acid, unsaturated ester compounds such as methyl methacrylate, butyl acrylate, vinyl acetate, styrene, aromatic vinyl compounds other than α-methylstyrene, unsaturated nitrile compounds other than acrylonitrile, pyridines And the like, and two or more of these can be used.

The heat-resistant thermoplastic resin is generally produced by an emulsion polymerization method, but may be produced by a suspension polymerization method or a bulk polymerization method.

The thermoplastic resin composition of the present invention contains 5 to 40 parts by weight of the graft copolymer [D] and 5 to 5 parts of the rubber-modified thermoplastic resin [F].
It is obtained by melt-kneading a mixture consisting of 30 parts by weight and 90 to 40 parts by weight of a heat-resistant thermoplastic resin [G] using a mixing roll, a screw type extruder or the like. At this time, if necessary, stabilizers, lubricants, plasticizers, dyes, pigments,
Fillers and the like can be added.

Here, the amount of the graft copolymer [D] is in the range of 5 to 40 parts by weight. When the amount is less than 5 parts by weight, the ability to develop impact strength is poor. Further, the rubber-modified thermoplastic resin [F] is 5 to 30 parts by weight, and if it is less than 5 parts by weight, a satisfactory matte surface cannot be obtained.
Even if it is more than the weight part, the improvement of the matting level is not seen,
Moldability and surface appearance deteriorate.

In the resin composition of the present invention, the rubber-modified thermoplastic resin [F] functions as a matting agent, and may be used in combination with other matting agents, such as JP-A-61-255919 and JP-A-62-1986. 48
The graft copolymer described in JP-A-709-709 can also be used.

〔Example〕

Hereinafter, the present invention will be described more specifically with reference to Examples, but the present invention is not limited to these Examples. The number of parts in the examples represents parts by weight unless otherwise specified, and the evaluation was made by the following method.

(1) Izod impact strength (Iz) Measured by ASTM D-256 (unit: kg · cm / cm).

(2) Melt flow index (MI) The melt flow index (MI) was measured at 220 ° C. under a load of 10 kg using a melt indexer manufactured by Toyo Baldwin Co., Ltd.

(3) Rockwell hardness (R) Measured according to ASTM D-785 (R scale).

(4) Vicat softening temperature (VST) Measured according to ISO R-306 (unit: ° C.). (5kg load) (5) Glossiness Digital gonio gloss meter manufactured by Suga Test Instruments Co., Ltd. (incident angle 60 °)
Was measured by

(6) Latex particle size Dynamic light scattering particle size distribution analyzer (scattering angle, manufactured by Otsuka Electronics Co., Ltd.)
90 °) and the freeze-dried latex were observed by electron microscopy.

Production of acid group-containing copolymer latex [B]: A mixture consisting of 2.5 parts of potassium oleate, 1 part of sodium dioctylsulfosuccinate, 0.3 part of sodium formaldehyde sulfoxylate and 200 parts of deionized water was charged into a polymerization vessel and charged with nitrogen. After the substitution, the monomer mixture and cumene hydroperoxide shown in Table 1 at 70 ° C.
One part of the composition was dropped and polymerized over 2 hours.
Then, stirring was continued for 1 hour to obtain a copolymer latex having a monomer conversion of 97% or more.

Enlargement operation: To 250 parts of polybutadiene rubber latex (average particle diameter of latex 0.08 μm, solid content 40% by weight), add the acid group-containing copolymer latex in the amount shown in Table 2 at 30 ° C.
Stir for minutes.

Production of graft copolymer [D-1]: A latex containing a solid content of 60 parts of the enlarged rubber-like copolymer [C-1] was placed in a polymerization vessel, and an operation of enlarging was performed. In this polymerization vessel, 110 parts of deionized water, 0.3 parts of dextrose,
0.005 part of ferrous sulfate, 0.2 part of sodium pyrophosphate, 1 part of dipotassium alkenyl succinate and 0.1 part of sodium hydroxide.
After adding 05 parts and raising the internal temperature to 60 ° C., 10 parts of acrylonitrile, 30 parts of styrene, and t-dodecyl mercaptan 0.2
And a mixture of 0.1 part of cumene hydroperoxide was added dropwise over 2 hours to carry out polymerization. The polymerization was completed by stirring for an additional hour after the peak due to the heat generated by the polymerization appeared. The monomer conversion determined from the polymer weight was 96.9%. The obtained polymer latex is poured into a 0.25% sulfuric acid aqueous solution, heated at 90 ° C. for 5 minutes to coagulate, washed, dehydrated, and dried.
A white powdered graft copolymer [D-1] was obtained.

Production of graft copolymer [D-2]: Same as production of [D-1] except that dipotassium alkenyl succinate was used in 2 parts using latex of enlarged rubber-like copolymer [C-2]. I went to. The monomer conversion was 97.3%.

Production of heat-resistant thermoplastic resin [G-1]: 2 parts of sodium dodecylbenzenesulfonate and sodium formaldehyde sulfoxylate in a polymerization reactor
0.5 parts, ethylenediaminetetraacetic acid disodium salt 0.0
A mixture consisting of 5 parts, 0.005 parts of ferrous sulfate and 250 parts of deionized water was charged and heated to 60 ° C., and then acrylonitrile was added.
20 parts, 60 parts of styrene, 20 parts of N-phenylmaleimide, t
A composition consisting of 0.15 part of dodecyl mercaptan and 0.3 part of cumene hydroperoxide was added dropwise over 2 hours and a half to polymerize. After stirring at 80 ° C. for 1 hour, a copolymer latex was obtained at a monomer conversion of 97.1%. 5
% Magnesium sulfate aqueous solution, coagulated at 100 ° C. for 30 minutes, washed, dehydrated, and dried to obtain a white powder heat-resistant thermoplastic resin [G-1].

Production of heat-resistant thermoplastic resin [G-2]: In a polymerization reactor, 3 parts of potassium oleate, 0.5 parts of dextrose, 0.5 parts of sodium pyrophosphate, ferrous sulfate
0.005 parts, 200 parts of deionized water and 10 parts of acrylonitrile,
α-methylstyrene 75 parts, t-dodecyl mercaptan 0.
One part was charged and heated to 60 ° C. After charging 0.5 parts of cumene hydroperoxide, 15 parts of acrylonitrile was added dropwise over 2 hours to carry out polymerization. After completion of conformity, 2
After stirring for an hour, a copolymer latex having a monomer conversion of 94.6% was obtained. It is poured into a 5% aqueous solution of magnesium sulfate, coagulated at 100 ° C. for 30 minutes, washed, dehydrated and dried to obtain a heat-resistant thermoplastic resin [G-
2] was obtained.

Production of thermoplastic resin [G-3]: 120 parts of deionized water, 1.0 part of polyvinyl alcohol and 0.003 part of potassium oleate were charged into an autoclave vacuum-degassed and purged with nitrogen, and stirred and mixed. Then, 25 parts of acrylonitrile, styrene A mixture consisting of 75 parts, 0.2 parts of azobisisobutyronitrile and 0.4 parts of t-dodecylmercaptan was charged and suspended. After suspension polymerization at 80 ° C. for 4 hours, the mixture was further stirred at 100 ° C. for 1 hour to give 98.1.
%. An acrylonitrile-styrylene copolymer was obtained in a yield of 30%. After washing, dehydration and drying, a bead-shaped thermoplastic resin [G-3] was obtained.

Production of resin composition: graft copolymer [D], rubber-modified thermoplastic resin
[F] and heat-resistant thermoplastic resin [G], etc. in Table 3
And an antioxidant (Mark AO20 / Mark PEP2)
4; Adeka Argus Chemicals) 0.2 / 0.2 parts and metal soap
0.5 part was added and mixed with a Hensiel mixer. Next
Use PCM-30 (Ikega Iron Works)
After melt-kneading at 260 ° C and 300rpm, pelletize
Was. This pellet is used for injection molding machine SAV-30A (Yamashiro Seiki
Various test pieces were molded at 260 ° C and used for evaluation.
Was. As the rubber-modified thermoplastic resin [F], Nippon Zeo
TMA-202 (Dynamic addition of NBR-containing rubber component and AS resin)
Sulfate). In addition, polycarbonate resin [G-
4] Novalex made by Mitsubishi Kasei Kogyo Use 7022A
Used.

As shown in Examples 1 and 2 in Table 3, it can be seen that the resin composition of the present invention has a high matting property, and is excellent in heat resistance and impact resistance. Comparative Example 1 shows that the rubber-like copolymer [C], which is larger than the average particle diameter range of the latex defined in the present invention, is inferior in impact strength. From Comparative Examples 2 to 5, it can be seen that when a large amount of the graft copolymer [D] or the rubber-modified thermoplastic resin [F] is blended, the molding processability deteriorates and the surface hardness decreases. Further, when the D component is small, the impact strength expression is poor, and when the F component is small, the matting property is poor. As shown in Example 3 or 4, heat-resistant thermoplastic resin [G]
By replacing a part of the resin with an AS resin or a polycarbonate resin, moldability or impact strength can be improved. Although a matte thermoplastic resin composition can be obtained in Comparative Example 6 using an AS resin as the thermoplastic resin [G], a maleimide copolymer (Example 1) or an α-methylstyrene copolymer (Example In the use example of Example 2), the matting level expressed by the same addition amount of the rubber-modified thermoplastic resin [F] is higher.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY The thermoplastic resin composition of the present invention has excellent matting properties required for vehicle accessories and the like, and has high heat resistance and impact resistance.

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Claims (1)

(57) [Claims] [I] A conjugated diene rubbery copolymer [A]
By adding 0.1 to 5 parts by weight of a solid content of the acid group-containing copolymer [B] latex to 100 parts by weight of the solid content of the latex, the conjugated diene-based rubbery copolymer [A] latex has an average particle diameter. It is enlarged to 0.15 to 0.45 μm, and the enlarged rubbery copolymer [C] latex 45 to 70
In the presence of parts by weight (at solids), the aromatic vinyl compound 60
A graft copolymer obtained by emulsion-polymerizing 55 to 30 parts by weight of a monomer mixture comprising 90 to 90% by weight, 10 to 40% by weight of an unsaturated nitrile compound and 30 to 0% by weight of a monomer copolymerizable therewith [D] 5 to 40 parts by weight, [II] 5 to 40 parts by weight of a rubber component containing at least 10% by weight of an unsaturated nitrile-conjugated diene rubbery copolymer, and 95 to 60 parts by weight of a thermoplastic resin [E] And 5 to 30 parts by weight of a rubber-modified thermoplastic resin [F] dynamically vulcanized by heating and kneading in the presence of a crosslinking agent of a rubber component, and [III] a heat-resistant thermoplastic resin [G]. 90 to 40 parts by weight, heat-resistant thermoplastic resin [G] is acrylonitrile 10 to 40
% By weight, styrene and / or α-methylstyrene 85 to 30
% Of the maleimide compound and 30 to 0% by weight of a monomer copolymerizable therewith, or the heat-resistant thermoplastic resin [G] is 10 to 40% acrylonitrile.
A heat-resistant thermoplastic resin composition comprising, by weight, 90 to 60% by weight of α-methylstyrene, and 30 to 0% by weight of a monomer copolymerizable therewith.