JPS604544A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide a composition having high heat deformation temperature and excellent impact resistance and thermal stability, and containing a copolymer obtained by polymerizing alpha-methylstyrene, a vinyl cyanide monomer and maleimide monomer, adding a maleimide monomer to the polymer, and subjecting to the two-step polymerization. CONSTITUTION:(A) 5-95pts.wt. of a copolymer obtained by (1) polymerizing 75-99pts.wt. of a mixture of (i) 50-95wt% alpha-methylstyrene, 5-35wt% vinyl cyanide monomer and 1-30wt% maleimide monomer until the polymerization ratio reaches 50-95% and (2) adding 25-1pts.wt. of a monomer containing a maleimide monomer as an essential component to the polymer and continuing the polymerization, is compounded with (B) 5-70pts.wt. of a graft copolymer obtained by grafting a mixture containing an aromatic vinyl monomer and a vinyl cyanide monomer as essential components in the presence of 20-80pts.wt. of a rubbery polymer, and (C) 0-80pts.wt. of a copolymer containing an aromatic vinyl monomer and a vinyl cyanide monomer, wherein (A)+(B)+(C) is 100pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thermoplastic resin composition that has a high heat distortion temperature and has an excellent balance between impact resistance and thermal stability.

Acrylonitrile/-getadiene-styrene terpolymer, so-called ABS resin, has an excellent balance of mechanical properties such as impact resistance, surface gloss, and processability.
Although it is used in a wide range of fields, it has the disadvantage that it cannot be used as a structural material under high-temperature conditions because of its low heat distortion temperature. Various methods have been proposed for the purpose of increasing the heat distortion temperature of ABS resin, but the most common method is to use a copolymer containing α-methylstyrene and acrylonitrile or a rubbery polymer instead of styrene. This is a method of mixing a graft copolymer grafted with a mixture of vinyl monomers such as styrene and acrylonitrile in the presence of styrene and acrylonitrile. The heat distortion temperature of the resin composition obtained by this method depends on the content of α-methylstyrene copolymerized with IJ Lux, so we produced a copolymer with as much α-methylstyrene content as possible, and Methods for obtaining high-quality resin compositions have been proposed (for example, in JP-A-5
5-78043 and Japanese Patent Publication No. 57-60373, etc.). However, the resin composition obtained by this method has problems in that the copolymer is brittle and has poor thermal stability, resulting in insufficient impact resistance and a narrow molding range.

Furthermore, as a method to obtain a copolymer with a high heat distortion temperature, α
- When copolymerizing the kings of methylstyrene, maleimide monomers, and acrylonitrile, a method has been proposed in which acrylonitrile is added in a controlled manner from the initial stage of polymerization (Japanese Unexamined Patent Publication No. 147534/1983). However, in this method, because the copolymerizability of α-methylstyrene and maleimide monomer is excellent, it is difficult to obtain a homogeneous copolymer, and the final polymerization rate is not high enough. Even when mixed with ABS resin, not only a satisfactory heat distortion temperature cannot be obtained, but also the impact resistance is insufficient.

Therefore, the present inventors conducted extensive studies with the aim of improving the above-mentioned drawbacks, and as a result, they polymerized a vinyl monomer mixture consisting of α-methylstyrene, vinyl cyanide monomer, and maleimide monomer. Next, a homogeneous copolymer is obtained by a so-called two-stage polymerization method, which involves adding a vinyl monomer whose essential component is a maleimide monomer to this polymerization system, continuing the polymerization, and completing the polymerization. The inventors have discovered that a resin composition meeting the above objectives can be obtained by mixing this copolymer with a graft copolymer, and have arrived at the present invention.

That is, the present invention provides multa) α-methylstyrene 50-95]ii-%
, a vinyl monomer consisting of 5 to 35% by weight of a vinyl cyanide monomer, 1 to 30% by weight of a maleimide monomer, and 0 to 40% by weight of another vinyl monomer copolymerizable with these. After polymerizing 75 to 99 parts by weight of the mixture until the polymerization rate becomes 50 to 95%, further add 25 to 1 part by weight of +b) a monomer or monomer mixture containing a maleimide monomer as an essential component. A copolymer obtained by continuing and completing the polymerization, provided that an aromatic vinyl monomer and a vinyl cyanide monomer are essential components in the presence of 20 to 80 parts by weight of a rubbery polymer. A graft copolymer obtained by graft polymerizing a vinyl monomer mixture and C) a vinyl monomer mixture containing an aromatic vinyl monomer and a vinyl cyanide monomer as essential components. The obtained copolymer was mixed with (A) 5 to 95 parts by weight and (B) 5 parts by weight.
~70 parts by weight and ~80 parts by weight of tclO (total 100 parts by weight)
The object of the present invention is to provide a thermoplastic resin composition which is mixed in a proportion of (parts by weight).

When polymerizing a vinyl monomer mixture containing a-methylstyrene, vinyl cyanide t' base type ft form, and a maleimide monomer as the main components, a monomer containing a maleimide monomer as an essential component is added in the latter half of the polymerization. The homogeneous copolymer (5) of the present invention obtained by adding a monomer or a monomer mixture to substantially complete the polymerization is a copolymer consisting only of α-methylstyrene and vinyl cyanide monomer. Compared to copolymers in which maleimide is simply copolymerized with polymers, a-methylstyrene, and vinyl cyanide monomers, not only does this have a higher heat distortion temperature, but it also has an improved thermal decomposition temperature. Furthermore, the copolymer (B) is strong because it contains a relatively small amount of maleimide monomer, and the resin composition of the present invention obtained by mixing the graft copolymer (B) exhibits high impact strength.

To obtain the copolymer of the present invention), first
50-90% by weight of α-methylstyrene in the process, especially 6
0 to 85% by weight, vinyl cyanide monomer 5 to 35% by weight, especially 10 to 30% by weight, maleimide monomer 1 to 30% by weight
75 to 99 parts by weight of a monomer mixture (a) consisting of 30% by weight, especially 3 to 20% by weight and θ to 40% by weight of other vinyl/L/base type polymers copolymerizable with these monomers is charged and polymerized until the polymerization rate reaches 50 to 95%, particularly 70 to 90%. If the copolymerization amount of α-methylstyrene is less than 50% by weight, the thermal deformation temperature of the obtained copolymer will be insufficient, and if it exceeds 90% by weight, the polymerization rate will not only slow down, but also the thermal decomposition temperature of the copolymer will be insufficient. This is not preferable because the mechanical strength decreases. Furthermore, if the copolymerization amount of vinyl cyanide monomer is less than 5% by weight, the polymerization rate becomes slow, and the thermal decomposition temperature and mechanical strength such as impact strength of the copolymer decrease.
If it exceeds 5% by weight, the heat deformation temperature of the copolymer becomes low, which is not preferable. Furthermore, if the copolymerization amount of the maleimide monomer is less than 1% by weight, the heat distortion temperature and thermal decomposition temperature of the copolymer will be low, and the effects of the present invention will not be sufficiently expressed, and if the copolymerization amount exceeds 30% by weight, the copolymerization temperature will be low. This is not preferable because the mechanical strength such as the impact strength of the combination decreases.

The copolymer (A) may contain 4 other vinyl monomers that can be copolymerized with the above monomers within a range that does not impair the effects of the present invention.
It can be contained up to 0% by weight.

In the first step in the production of copolymer (5), 75 to 99 parts by weight of the monomer mixture (a) has a polymerization rate of 50 to 95% by weight.
Polymerization continues until . Here, the monomer mixture ta
If the first step is stopped at a stage where the polymerization rate of + is less than 50% by weight, either the thermal deformation temperature or mechanical strength such as impact strength of the resulting copolymer will decrease, and the polymerization rate of the first step will decrease. If it exceeds 95% by weight, the polymerization time becomes significantly longer and economical efficiency decreases, which is not preferable.

In order to obtain the copolymer of the present invention, in the second step following the above first step, 10 to 100% by weight, especially 20 to 100% by weight of BL maleimide monomer is added to the polymerization system as an essential component. (b) 25 to 1 part by weight of a monomer or monomer mixture containing 25 to 1 part by weight of the monomer or monomer mixture is added to continue the polymerization until it is substantially completed. If the number of parts of the TBL monomer or monomer mixture is less than 1 part by weight, the copolymer will have a high heat distortion temperature. If the amount exceeds 25 parts by weight, only a copolymer with reduced heat distortion temperature or impact resistance will be obtained, which is not preferable. A single monomer or a mixture of a maleimide monomer and a vinyl cyanide monomer are particularly preferably used.

In the copolymer 1A) of the present invention, the sulvinyl monomers used in the first step are vinyl cyanide monomers of α-methylstyrene and acrylonitrile, and maleimide monomers represented by the following general formula (1). It is a quantity.

R, R2 1 C=C 1 (However, R+, R2, R.+ in the formula each independently represents hydrogen, halogen, substituted or unsubstituted alkyl group having 1 to 20 carbon atoms, aryl group, etc.) Maleimide Specific examples of monomers include maleimide, N-methylmaleimide,
N-ethylmaleimide, N-butylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide i'
O”J:.

and N-(p-bromophenyl/I/)maleimide, among which N-phenylmaleimide and N-cyclohexylmaleimide are preferably used. Two or more of the above maleimide monomers may be used in combination. Furthermore, other vinyl monomers that can be copolymerized with these monomers include styrene, vinyl citrenine, and p-tert.
- Aromatic vinyl monomers such as phthylnutyrene and halogen-substituted styrene (excluding α-methylstyrene),
Examples include (meth)acrylic acid monomers such as acrylic acid and methacrylic acid and their methyl, ethyl, proyl, and n-butyl esters.

Furthermore, the monomer or monomer mixture used in the second step is maleimide, N~cyclohexy!, which was explained in the first step.
Remaleimi F OJ: iQ' N-fu, :c Contains a maleimide monomer such as nylmaleimide as an essential component, and further contains cyanide vinyl monomers such as acrylonitrile and methacrylonitrile, and α-methyl as necessary. Styrene excluding styrene, l-renin on vinyl and p-te
Aromatic vinyl monomers such as rt-butylstyrene, acrylic acid and methacrylic acid, and their methyl, ethyl, propyl, and n-butyl esters (meth)ac IJ
) U means those containing acid-based monomers.

For the production of copolymer (A), known polymerization methods such as emulsion polymerization, solution polymerization, and bulk polymerization can be used. In the presence of 20 to 80 parts by weight, especially 40 to 70 parts by weight, aromatic vinyl monomers and vinyl cyanide monomers are essential components, and if necessary, other vinyl copolymerizable with these is added. It is obtained by graph l-polymerizing 20 to 80 parts by weight, particularly 60 to 30 parts by weight of a vinyl monomer mixture consisting of vinyl monomers. If the proportion of the rubbery polymer is less than 20 parts by weight, it is difficult to obtain a resin composition that has both a high heat deformation temperature and high impact strength, but if it exceeds 80 parts by weight, the rubbery polymer becomes insufficiently dispersed in the resin. This is not preferred because the appearance of the molded product made from the composition is impaired.

Graph 1 - Rubbery polymers used to obtain copolymer IB) include polybutadiene rubber (P'B'D), styrene/decdiene copolymer rubber (SBR), and acrylonitrile/bucciene copolymer rubber ( Examples include diene rubbers such as NBR), acrylic rubbers such as polybutyl acrylate, and ethylene-propylene-nonconjugated diene rubbers (EPDM).

The vinyl monomer used to obtain the graft copolymer (B) includes styrene, p-methylstyrene and p-
Nucleically substituted alkylene styrene such as tert-butylstyrene. Aromatic vinyl monomers such as and a-methifrestyrene carbs and vinyl cyanide monomers such as acrylonitrile and methacrylonitrilyl are essential components,
Other vinyl monomers that can be copolymerized with these include acrylic acid, methacrylic acid and its methyl, ethyl, propyl/L', +1-butyl esteryl st monomer, maleimide, N-methinone maleimide, N -ethylmanimide, N-butylmaleimide,
Examples include maleimide monomers such as N-cyclohexylmanimide, N-phenylmaleimide, and N-(p-bromophenyl)maleimide.

Graph 1 - There are no particular restrictions on the method for producing copolymer tB), and known polymerization methods such as emulsion polymerization, emulsion-suspension polymerization, suspension polymerization, solution polymerization, bulk polymerization, and block-) nephroturbid polymerization are used. can do.

The copolymers tC) used in the present invention are styrene, p-methylstyrene, p-tert-butylstyrene, and other nuclear-substituted alkylstyrenes and α-methyl 1N/71. Aromatic vinyl monomers such as tyrene and vinyl/V monomers such as acrylonitrile and methacrylonitrile are essential components, and if necessary, acrylic acid, methacrylic acid and histochloride are added. Methyl, ethyl, propyl,
It is a copolymer obtained by polymerizing a vinyl monomer mixture containing n-butyl ester, such as acrylonitrile! Restin V-copolymer,
acrylonitrile-p-methylstyrene copolymer, acrylonitrile-p-methylstyrene copolymer
fi combination, acrylonine-methyl methacrylate-1.Δ, and the like.

Regarding the method for producing the copolymer tC), known polymerization methods such as emulsion polymerization, suspension polymerization, bulk polymerization, and bulk-suspension polymerization can be used.

The thermoplastic resin composition of the present invention comprises the above-mentioned copolymers 5 to 9.
5 parts by weight, especially 20 to 85 parts by weight, 5 to 70 parts by weight of Copolymer (B), especially 10 to 50 parts by weight
parts by weight and the above copolymer +Q 0 to 80 parts by weight.
It is obtained by mixing [B) + FC+ so that the total amount is 100 parts by weight. If the proportion of the copolymer is less than 5 parts by weight, the heat distortion temperature of the resin composition will be insufficient, and if it exceeds 95 parts by weight, the impact resistance of the resin composition will decrease, which is not preferable. Also, graft copolymer [B)
If the proportion is less than 5 parts by weight, the impact resistance of the resin composition will be insufficient, and if it exceeds 70 parts by weight, a high heat distortion temperature will not be obtained, which is not preferable. Furthermore, if the proportion of the copolymer tC) exceeds 80 parts by weight, both the heat distortion temperature and the J-impact resistance will be lowered, which is not desirable.

The proportion of the rubbery polymer (contained in the graft copolymer tB) in the entire composition is 1 to 4% by weight fj1%,
Particularly suitable is 5 to 30% by weight, and the rubbery polymer is 1% by weight.
If it is less than 40% by weight, the impact resistance of the resin composition will be low, and if it exceeds 40% by weight, the processability and tensile strength of the resin composition will be significantly reduced, which is not desirable.

In the present invention, copolymer (5), graph I copolymer (
There are no particular restrictions on the method of mixing B) and the copolymer (C), but they are usually melt-kneaded using an extruder, Vanoverry mixer, Nigoo, roll, or the like.

The thermoplastic resin composition of the present invention may further contain other thermoplastic polymers, such as styrene-maleic anhydride copolymer, I)
-tert-butyl styrene-maleic anhydride copolymer, p-methylstyrene-maleic anhydride copolymer, polycarbonate, polyamide, polybutylene thirephthalate
1., polybutylene thirephthalate 1-, polyphenylene oxide, etc. can be mixed to adjust the desired performance. In addition, during kneading, heat stabilizers such as hinted phenol antioxidants and phosphorus antioxidants, ultraviolet absorbers, light stabilizers, flame retardants, lubricants, colorants, pigments, and various additives are added after kneading. Glass fibers, metal fibers, reinforcing agents, fillers, etc. can also be mixed.

Hereinafter, the present invention will be explained in more detail with reference to Reference Examples, Examples, and Comparative Examples. Note that parts and % represent parts by weight and % by weight, respectively.

Heat distortion temperature is ASTM D-648-56 (18,56
load/c11 load), Izotsu impact strength is ASTM D
-256-56A. The thermal decomposition temperature was determined by increasing the temperature at a rate of 10° C./min under a nitrogen stream using a thermogravimeter, and was determined by the temperature at which the sample weight decreased by 3% by weight. The polymerization rate was determined by gas chromatography using unreacted monomer Ec.
Calculated by quantifying the body.

Reference Example 1 (Production of copolymer + A) Copolymers A-1 to A-12 were produced by the following method.

(Copolymers A-1 to A-11) In a stainless steel autoclave, 150 parts of pure water, 1.5 parts of sodium lauryl sulfate, 0.5 parts of glucose, 0.4 parts of birophosphate sorta, and 0.005 parts of ferrous sulfate. After purging with nitrogen, heat to 85°C while stirring. Next, an aqueous solution prepared by dissolving 0.2 parts of cumene hydroperoxide and 25 parts of sodium lauryl sulfate in 20 parts of pure water was added at a constant rate over 16 hours to one of the batches.

At the same time, 1+1+ monomers shown in Table 1 were charged at a constant rate from another charging port over a period of 8 hours, and after reaching the desired polymerization rate, monomer (11) was added at a constant rate. I prepared it. The polymerization temperature conditions were controlled at 85'Ic from the start of polymerization until the end of charging the monomer (n), then raised to 90°C and held for 1 hour after the end of charging the aqueous solution containing the initiator. After the polymerization was completed, a portion of the copolymer latex was sampled, and the unreacted monomer was quantified by Cass chroma I-graphy to calculate the final polymerization rate.

Of the copolymer latexes obtained, unreacted monomers were removed from A-0 by steam distillation, and the rest was coagulated using magnesium sulfate, washed with water, filtered, and dried. , powder copolymers A-1 to A-11
I got it.

(Copolymer A-12) In a stainless steel autoclave, add 150 parts of pure water, 2.5 parts of sodium lauryl sulfate, 0.5 parts of glucose, and PIOIJ.
0.4 parts of sodium sulfuric acid, 11m, 005 parts of sulfuric acid, and monomer (I) in Table 1 were added, and after purging with nitrogen, the mixture was heated to 8 parts with stirring.
The temperature was raised to 5°C. Then, an aqueous solution prepared by dissolving 0.2 parts of cumene hydroperoxide and 1.5 parts of sodium lauryl sulfate in 20 parts of pure water was added at a constant rate over 12 hours through one of the charging ports. The polymerization rate 1 hour after the start of polymerization was 17
．． It was 6%. From this point onwards, over 8 hours, 9.2 parts of acrylonitrile was added until the unreacted monomer ratio was α-methylstyrene/N-phenylmaleimide+acrylonitrile-73.
The mixture was added while being adjusted within the range of /27 to 78/22. However, when the polymerization rate reaches 58%, unreacted N-phenylmaleimide monomer disappears, and the polymerization after the polymerization rate of 58% essentially becomes a copolymerization of α-methylstyrene and acrylonitrile. The polymerization rate and unreacted monomer composition during the process were determined by sampling latex in small quantities from the autoclave and analyzing it by gas chromatography. The obtained copolymer latex was post-treated under the same conditions as A-1 to obtain powder copolymer A-12.

Reference Example-2 (Production of Graft Copolymer CB+) (Graft Copolymers: B-1 to B-3, B-5 and B-6) 80 parts of pure water and 0 glucose in a stainless steel autoclave
．． 5 parts, 0.4 parts of pyrophosphate sorter, ferrous sulfate Q,
005 parts and a predetermined amount of polybutadiene latex shown in Table 2 were charged, and after replacing with nitrogen, the temperature was raised to 70° C. with stirring. Next, a monomer mixture shown in Table 2 was added at a constant rate over 5 hours, and 25 parts of pure water, 2.5 parts of potassium oleate, and 0.2 parts of cumene hydroperoxide were added from a separate charging port. An aqueous solution consisting of was added at a constant rate over 6.5 hours. After the addition was completed, the temperature was raised to 75°C and polymerization was continued for an additional hour. After the polymerization was completed, a small amount of the graft copolymer latex was sampled, and the amount of unreacted monomer was determined by gas chromatography to calculate the final polymerization rate. Each graft copolymer latex was coagulated with magnesium sulfate, washed with water, dehydrated, and dried to obtain a powdered graft copolymer.

(Graft copolymer, B-4) In an autoclave purged with nitrogen, the amounts of ethylene-propylene-nonconjugated leeno copolymer rubber (EPT3045 manufactured by Mitsui Petrochemical Co., Ltd.) shown in Table 2, styrene, acrylonitrile, and toluene 150% were added. part and n-hexane 15
After charging with 0 parts and thoroughly stirring to dissolve, 0.5 parts of benzoyl peroxide was added. Furthermore, 0.3 parts of methyl methacrylate/acrylamide = 20/80 copolymer and 01 parts of monosodium phosphate were dissolved in 200 parts of pure water, and 1 aqueous solution was added thereto. After 1 time, the mixture was heated to 80°C with vigorous stirring.
The temperature rose to . Polymerize at 80°C for 5 hours and then at 100°C for 1 hour to perform graft polymerization. After the polymerization was completed, toluene, n-hexane and unreacted monomers were removed by steam distillation to obtain a graft copolymer (B-4).

Reference Example-3 (Production of copolymer (q)) Dissolve 0.06 part of methyl methacrylate-1/acrylamide 20/80 copolymer and 0.05 part of monostorium phosphate in 150 parts of pure water. After adding the aqueous solution to the crepe and stirring, add 72 parts of styrene, 28 parts of acrylonitrile, 0.4 part of tert-dotesylmercapkun, and 0.4 part of azobisisobutyronitrile. The gas phase was replaced with nitrogen, and the temperature was raised to 70°C while stirring vigorously. Polymerization was carried out at 70°C for 3 hours and then at 110°C for 1 hour.

The conversion rate after the completion of polymerization was 99%. The obtained pea-shaped copolymer (C) was washed with water, dehydrated, and dried.

Examples and Comparative Examples Manufactured in Reference Example 1, J Copolymers A-1 to A-12, Reference Example 2, T Cograph 1 Copolymers B-1 to B-6, and Reference Example 3 Copolymer C-1 was mixed at the mixing ratio shown in Table 3, and 0.2 parts of triphenyl phosphite and octadecyl 3-(3,5-di-te) were added as stabilizers.
After adding 0.2 parts of rt-butyl-4-hydroxyphenol-propione, the mixture was melt-kneaded and pelletized using an extruder. Each Pereso I- is then injection molded,
Each test piece was prepared and its physical properties were measured. The results are shown in Table 3.

As is clear from the results in Table 3, the thermal “TJ plastic 1” of the present invention
The No. 41 resin compositions (Examples 1 to 6) are excellent in both mechanical properties represented by heat distortion temperature and impact strength, and thermal stability represented by thermal content [11 temperature].

On the other hand, in the copolymer (A), the first step and the second step
- When either maleimide monomer is not included in the culm, the resin compositions (Comparative Examples 1 and 5) have no changes in heat distortion temperature and thermal stability, and α in the copolymer formula
- When the content of medylstyrene is 90 parts by weight or more,
The resin composition (Comparative Example 2) lacks impact resistance. α-Methyl styrene of the claw union H: / Contains 4-
3 ffi or 50% by weight of the resin composition (
Comparative Example 3) has a lower heat distortion temperature. When the content of the maleimide intermediate in the copolymer formula is 30% by weight or more, the resin composition (Comparative Example-4) has poor impact resistance, and the copolymer (A+) has poor impact resistance, and When added, the thermal stability of the resin composition (Comparative Example-6) is not improved. Graph 1 - When the rubbery polymer content in copolymer tBl is 80% or more, or 20 parts by weight or less In this case, the resin compositions (Comparative Examples 7 and 8) have extremely poor impact resistance. The products (Comparative Examples 9 and 1o) were inferior in both impact resistance and heat distortion temperature, making it impossible to obtain a resin composition with desirable properties. The resin composition (Comparative Example 11) in which the monomer content is 30 parts by weight or more cannot accommodate the heat distortion temperature.

Special pestle applicant Higashishi Kaisha Ltd. 9-1 Oecho, Minato-ku, Nagoya City Toshi Co., Ltd. Nagoya Plant 2 shots by Akihiko Kishimoto 9-1 Oecho, Minato-ku, Nagoya City Toshi Co., Ltd. Nagoya Plant

Claims (1)

[Scope of Claims] Q) (alα-methylstyrene 50-9!MjJ amount%
, a vinyl monomer consisting of 5 to 35% by weight of a vinyl cyanide monomer, 1 to 30% by weight of a maleimide monomer, and 0 to 40% by weight of another vinyl monomer copolymerizable with these. After polymerizing 75 to 99 parts by weight of the mixture until the polymerization rate becomes 50 to 95%, further add (b) 25 to 1 part by weight of a monomer or monomer mixture containing a maleimide monomer as an essential component. In addition, the copolymer obtained by continuing the polymerization and completing it, 1B) = 'Aromatic vinyl monomer and cyanide vinyl monomer in the presence of 20 to 80 parts by weight of mucous polymer. A graft copolymer obtained by graft polymerization of a vinyl monomer mixture as an essential component, and Ic) a vinyl monomer having an aromatic vinyl monomer and a cyanated vinyl p monomer as essential components. 5 to 95 parts by weight of the copolymer obtained by polymerizing the mixture, ([3)
5 to 70 parts by weight and C1O to 80 parts by weight (total 10
0 parts by weight) A thermoplastic resin composition mixed in a certain ratio.