JP2000119506A - Resin composition excellent in impact resistance and rigidity - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin composition excellent in heat resistance, impact resistance and fluidity, and having a small dependence of impact resistance upon thickness. SOLUTION: This resin composition comprises (A) aromatic polycarbonate resin, (B) a hydrogenated styrenic elastomer, (C) a copolymer resin obtained from an aromatic vinyl monomer and a vinyl cyanide monomer and containing vinyl cyanide units in an average content of 2-15 wt.% and (D) poly(phenylene ether) resin. The component C consists of (a) 5-50 wt.% copolymer containing vinyl cyanide units in a content of 2-5 wt.%, (b) 5-50 wt.% copolymer containing vinyl cyanide units in a content of 5-10 wt.% and (c) 5-50 wt.% copolymer containing vinyl cyanide units in a content of 10-15 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin composition having excellent heat resistance, impact resistance and rigidity, and having little impact resistance thickness dependency.

[0002]

2. Description of the Related Art Polycarbonate resins are used in various fields such as automobile parts, home electric parts, and OA equipment parts because of their excellent heat resistance and impact resistance. However, the impact resistance of polycarbonate resin is extremely strong in the direction perpendicular to the resin flow direction due to the orientation of the resin at the time of injection molding in the molded product obtained by injection molding. There is a disadvantage that the thick part in the direction becomes brittle. A technique of blending polycarbonate resin / ABS resin is well known in order to improve the disadvantage of the thickness dependence on impact resistance characteristic of the polycarbonate resin. This technology applies AB resin to polycarbonate resin.
The purpose is to reduce the dependence of the orientation of the polycarbonate resin by adding crosslinked rubber particles that are not easily affected by the orientation of the S resin. The present invention is a technique of adding a hydrogenated styrene-based elastomer, which is an uncrosslinked rubber, in order to eliminate the disadvantage of the thickness dependence of the impact resistance of a polycarbonate resin, unlike these techniques.

JP-A-7-324158 discloses an aromatic polycarbonate resin / rubber reinforced polystyrene resin / a copolymer of vinyl cyanide and styrene / polyphenylene ether resin for the purpose of improving the moldability of the aromatic polycarbonate resin. A blend composition is disclosed. This technology also aims to improve the flow characteristics and impact resistance of the aromatic polycarbonate resin by adding high-impact polystyrene to the aromatic polycarbonate resin by using crosslinked rubber particles.

[0004] The hydrogenated styrene elastomer used in the present invention refers to a thermoplastic elastomer obtained by hydrogenating a double bond of a conjugated diene block by a block copolymer comprising an aromatic vinyl unit and a conjugated diene unit. Say. The hydrogenated conjugated diene block has no double bond required for crosslinking, so the hydrogenated styrene elastomer is an uncrosslinked rubber and the impact resistance of the hydrogenated styrene elastomer itself is affected by the orientation of the resin during injection molding. Receive strongly.
It is a completely unexpected effect that the dependency of the impact resistance of the aromatic polycarbonate resin on the thickness is reduced by blending the hydrogenated styrene elastomer with the aromatic polycarbonate.

[0005] A simple blend composition of a polycarbonate resin and a hydrogenated styrenic elastomer results in only a brittle composition because the polycarbonate resin and the hydrogenated styrenic elastomer are incompatible.
The present invention improves the compatibility between the polycarbonate resin and the hydrogenated styrenic elastomer by an average of 2 to 15% by weight.
A styrene / vinyl cyanide copolymer having a specific composition distribution containing a low vinyl cyanide content is effective in improving the compatibility between an aromatic polycarbonate and a hydrogenated styrene-based elastomer, and the resulting composition Has been found to be a composition having extremely high impact resistance and no thickness dependence.

[0006] Further, the polycarbonate resin has a drawback that the fluidity is low and the moldability is poor. As described above, an ABS resin (acrylonitrile-butadiene-styrene polymer) or MBS resin (methyl methacrylate-butadiene-styrene polymer) is used as the polycarbonate resin.
In addition, there is an attempt to improve the fluidity while maintaining high impact resistance (Japanese Patent Publication Nos. 38-15225 and 42-11496). An attempt to improve the fluidity by adding a styrene resin to a polycarbonate resin is proposed in Japanese Patent Publication No. 43-6295.

However, the polycarbonate resin and the polystyrene resin have a disadvantage that the impact resistance is lowered due to poor compatibility. And German Patent Publication 42
No. 0247 discloses a resin composition comprising polycarbonate, polyphenylene ether, and styrene-ABS resin. However, the resin composition of this publication has improved heat resistance, but has a disadvantage of poor impact resistance.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to develop a resin composition having excellent heat resistance, impact resistance, excellent fluidity, and little impact resistance thickness dependency.

[0009]

That is, the present invention relates to (A) an aromatic polycarbonate resin, (B) a hydrogenated styrene-based elastomer, and (C) an aromatic vinyl monomer containing an average of 2 to 15% by weight of vinyl cyanide. A copolymer resin of a monomer and a vinyl cyanide monomer, wherein the copolymer resin is a)
5-50 copolymers having a vinyl cyanide content of 2-5% by weight
B) 5 to 50% by weight of a copolymer having a vinyl cyanide content of 5 to 10% by weight, c) a vinyl cyanide content of 10
5 to 50% by weight of a copolymer of 15 to 15% by weight, wherein a)
+ B) + c) is a resin composition comprising a copolymer resin of an aromatic vinyl monomer and a vinyl cyanide monomer, which is a mixture of (b) and (c) in total of 100% by weight, and (D) a polyphenylene ether resin.

The aromatic polycarbonate of the component (A) used in the present invention may be a phosgene method in which an aromatic dihydric phenol compound is blown with phosgene in the presence of a caustic alkali and a solvent, or an aromatic dihydric phenol compound and a carbonate Examples thereof include those obtained by a transesterification method in which transesterification with diethyl is carried out in the presence of a catalyst, and may be a homo- or copolymer, and the viscosity-average molecular weight is preferably in the range of 10,000 to 1,000,000. The dihydric phenolic compound used in the present invention is 2.2'-bis (4-hydroxyphenyl) propane, 2,2'-bis (4-hydroxy-3,5-dimethylphenphenyl) propane, bis (4 -Hydroxyphenyl) methane, 2,2'-bis (4-hydroxyphenyl) butane, 2,2'-bis (4-hydroxy-3,5-dipropylphenyl) propane, 1,1'-bis (4- Hydroxyphenyl) cyclohexane, 1-phenyl-1,1′-bis (4-hydroxyphenyl) ethane and the like, and 2,2′-bis (4-hydroxyphenyl) propane [bisphenol A] is particularly preferable. Further, dihydric phenols may be used alone or in combination.

The hydrogenated styrenic elastomer (B) used in the present invention is prepared by anionic polymerization, and is a block copolymer composed of an aromatic vinyl unit and a conjugated diene unit. It is obtained by addition. The conjugated diene monomer constituting the conjugated diene block is butadiene, isoprene or the like.
As a monomer constituting the aromatic vinyl block, one or two of styrene, α-methylstyrene, 1,1-diphenylethylene and P-ter-butylstyrene are used.
More than one kind can be selected, and among them, styrene is preferable. The block copolymer is a block copolymer comprising at least one polymer block (S) mainly composed of a vinyl aromatic compound and at least one polymer block mainly composed of a hydrogenated conjugated diene. , For example, SB, S
-B-S, B-S-B-S, (S-B-) nSi and the like. In the present invention, these block copolymers have a vinyl aromatic content (bound styrene content) of 50% by weight or more.
It is preferable to use at least one of less than 5% by weight and at least one of those having a bound styrene content of at least 10% by weight and less than 50% by weight.

In order to increase the compatibility between the aromatic polycarbonate resin and the hydrogenated styrene-based elastomer via the copolymer containing vinyl cyanide as the component (C), the amount of the bound styrene of the hydrogenated styrene-based elastomer is high. It is more preferable, but if the amount of bound styrene is too high, the function as a reinforcing rubber is reduced, resulting in a composition having low impact resistance.
In order to satisfy the requirements of improved compatibility and improved impact resistance at a fixed amount of the hydrogenated styrene-based elastomer in the resin composition, it is preferable to use a combination of several hydrogenated styrene-based elastomers having different bound styrenes. .

In the present invention, the component (C) plays an important role in determining the physical properties of the composition of the present invention, and the aromatic polycarbonate resin (A) in the composition and the component (B) ) Has the function of improving the compatibility of the component (D). The AN content in the polymer of component (C) is in the range of 2 to 15% by weight, and more preferably in the range of 4.0 to 10.0% by weight. When the AN content is less than 2.0% by weight or exceeds 15.0% by weight, the impact resistance of the composition is significantly reduced. The aromatic vinyl monomer (C) is, for example, styrene, α-methylstyrene,
p-Methylstyrene, pt-butylstyrene and the like are preferable, and styrene is preferable. Examples of the vinyl cyanide monomer of the component (C) include, for example, acrylonitrile and methacrylonitrile. Is acrylonitrile. If necessary, one or more monomers copolymerizable with the aromatic vinyl monomer and the unsaturated nitrile monomer can be introduced as components of the copolymer. The copolymerizable monomer is an acrylate ester having an alkyl group having 1 to 8 carbon atoms such as methyl acrylate and butyl acrylate, and a methacryl having an alkyl group having 1 to 8 carbon atoms such as methyl methacrylate. Α, β-unsaturated carboxylic anhydrides such as acid esters, maleic anhydride and itaconic anhydride; and maleimides such as maleimide and N-phenylmaleimide.

Regarding the composition distribution of vinyl cyanide content in the component (C) of the present invention, the vinyl cyanide content is a) 2
B) 5 to 10% by weight of copolymer 5 to 50% by weight c) 10 to 15% by weight of copolymer 5 to 50% by weight (where a) + B) + c) having a composition distribution of 100% by weight) and having an average vinyl cyanide content of 2 to 15% by weight in the entire copolymer is preferred. The compatibility between the copolymer of the component C and the styrene block of the hydrogenated styrene elastomer of the component B is good for the copolymer having a low vinyl cyanide content when the vinyl cyanide content is in the range of 2 to 15% by weight. Yes, the compatibility with the aromatic polycarbonate of the component A tends to be preferably a copolymer having a high vinyl cyanide content, so that a mixture of these may be better as the compatibility of the entire composition. . The polyphenylene ether (hereinafter abbreviated as PPE) of the component (D) used in the present invention is a homopolymer and / or a copolymer comprising a bonding unit represented by the following formula.

[0015]

Embedded image

However, R1, R2, R3 and R4 are each selected from the group consisting of hydrogen and substituted hydrocarbon groups, and may be different from each other. Specific examples of the PPE include poly (2,6-dimethyl-1,4-phenylene ether) and a copolymer of 2,6-dimethylphenol and 2,3,6-trimethylphenol. Poly (2,6-dimethyl-1,4-phenylene ether) is preferred. Reduced viscosity of PPE (0.5 g / d
1, chloroform solution, 30 ° C) is 0.2-0.70 d
1 / g, preferably 0.3 to 0.60
More preferably, it is in the range of dl / g. The reduced viscosity of PPE can be adjusted by adjusting the amount of catalyst used in the production. The method for producing PPE can be easily produced, for example, by polymerization using a complex of cuprous salt and an amine as a catalyst according to the method described in US Pat. No. 3,306,874.
No. 061075, U.S. Pat. No. 3,257,357, U.S. Pat. No. 3,257,358, and Japanese Patent Publication No. Sho.
It can be easily produced by the method described in JP-A-2-17880 and JP-A-50-51197.

The proportion of the aromatic polycarbonate resin (A) in the composition of the present invention is preferably 25 to 85% by weight, more preferably 30 to 80% by weight. (B)
The hydrogenated styrene-based elastomer as a component is 3 to 50.
% By weight, more preferably 5 to 40% by weight. The copolymer of the aromatic vinyl monomer containing 2 to 15% by weight of the vinyl cyanide monomer as the component (C) and the vinyl cyanide monomer is preferably 2 to 30% by weight, more preferably. Is 3 to 20% by weight. The polyphenylene ether (D) is preferably from 2 to 30% by weight, more preferably from 3 to 30% by weight. When the blending ratio of the component (A) is less than 25% by weight, impact resistance and rigidity are inferior.
If the content is more than the weight%, the fluidity is poor. (B) component is 3% by weight
If it is less than 50%, the fluidity is poor, and if it exceeds 50% by weight, the elastic modulus is poor. If (C) is less than 2% by weight or more than 30% by weight, the impact resistance is poor. If (D) is less than 2% by weight, the improvement in heat resistance is insufficient, and if it exceeds 30% by weight, the fluidity is poor.

The composition of the present invention may be used, if necessary, in the form of one or more selected from the group consisting of ultraviolet absorbers, hindered amine light stabilizers, antioxidants, light-blocking agents, metal deactivators and quenchers. Agent (Ι) can be added. The ultraviolet absorber becomes a keto-type molecule by absorbing light energy and transferring an intramolecular proton (benzophenone, benzotriazole-based), or by cis-trans isomerization (cyanoacrylate-based), It is a component that releases and detoxifies as heat energy. Specific examples are 2,
4-dihydroxybenzophenone, 2-hydroxy-4
-Methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 5,5'-methylenebis (2-
2- such as hydroxy-4-methoxybenzophenone)
Hydroxybenzophenones, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2-
(2′-hydroxy-5′-t-octylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′,
5′-di-t-butylphenyl) benzotriazole,
2- (2'-hydroxy-3 ', 5'-di-t-butylphenyl) -5-chlorobenzotriazole, 2-
(2′-hydroxy-3′-t-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-dicumylphenyl) benzotriazole, 2,2′- 2- (2 ′) such as methylenebis (4-t-octyl-6-benzotriazolyl) phenol
-Hydroxyphenyl) benzotriazoles phenyl salicylate, resorcinol monobenzoate, 2,
4-di-t-butylphenyl-3 ′, 5′-di-tert-butyl-4′-hydroxybenzoate, hexadecyl-
Benzoates such as 3,5-di-t-butyl-4-hydroxybenzoate, substituted oxanilides such as 2-ethyl-2′-atoxiogazide, 2-ethoxy-4′-dodecyloxanilide, and ethyl -Α-cyano-
Cyanoacrylates such as β, β-diphenylacrylate and methyl-2-cyano-3-methyl-3- (p-methoxyphenyl) acrylate.

The hindered amine-based light stabilizer includes:
Decomposes hydroperoxides generated by light energy to produce stable NO radicals, N-OR, N-OH
And a component for stabilizing. Specific examples thereof include 2,2,6,6-tetramethyl-4-piperidyl stearate, 1,2,2,6,6-pentamethyl-
4-piperidyl stearate, 2,2,6,6-tetramethyl-4-piperidyl benzoate, bis (2,2.
6,6-tetramethyl-4-piperazyl sebacate, bis (1,2,2,6,6-pentamethyl-4-piperazyl) sebacate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) 1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6
-Pentamethyl-4-piperidyl) -1,2,3,4-
Butanetetracarboxylate, bis (1,2,2,
6,6-pentamethyl-4-piperidyl) di (tridecyl) -1,2,3,4-butanetetracarboxylate, bis (1,2,2,6,6-pentamethyl-4-piperazyl) -2- Butyl-2- (3 ', 5'-di-t-
Butyl-4-hydroxybenzyl) malonate, 1-
(2-hydroxyethyl) -2,2,6,6-tetramethyl-4-piperidinol / diethyl succinate polycondensate, 1,6-bis (2,2,6,6-tetramethyl-4
-Piperidylamino) hexane / 2,4-dichloro-6
-T-octylamino-s-triazine polycondensate, 1,
6-bis (2,2,6,6-tetramethyl-4-piperidylamino) hexane / 2,4-dichloro-6-morpholino-s-triazine polycondensate.

The antioxidant is a component for stabilizing a generated peroxide radical such as a hydroperoxy radical or decomposing a generated peroxide such as a hydroperoxide by heat molding or light exposure. It is. Specific examples thereof include a hindered phenol-based antioxidant and / or
Or a peroxide decomposer. The former is a radical chain inhibitor, and the latter decomposes the peroxide formed in the system into more stable alcohols to prevent autoxidation. The above-mentioned hindered phenol-based antioxidants include 2,6-dibutyl butyl-4-methylphenol, styrenated phenol, and n-octadecyl 3- (3,5-dibutyl butyl-4-hydroxy). Phenyl) propionate, 2,2-methylenebis (4-methyl-6-tert-butylphenol), 2-tert-butyl-6-
(3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, 2-
[1- (Hydroxy-3,5-ditacharpentylphenyl) ethyl] -4,6-ditacharpentylphenyl acrylate, 4,4'-butylidenebis (3-methyl-6-tert-butyl) Phenol), alkylated bisphenol, tetrakis [methylene 3-
(3,5-Diterbutyl-4-hydroxyphenyl) propionate] methane, 3,9-bis [2- [3
-(3-tert-butyl-4hydroxy-5-methylphenyl) -propionyloxy] -1,1-dimethylethyl] -2,4,8,10-tetraoxaspiro [5.
5] Undecane and the like. In addition, the peroxide decomposer,
Organophosphorus peroxide decomposers such as trisnonylphenol phosphite, trisphenyl phosphite, tris (2,4-ditertbutylbutylphenyl) phosphite or dilauryl 3,3′-thiodipropionate, dimyristyl 3,3 ′ -Thiodipropionate, distearyl 3,3'-thiodipropionate, pentaerythrityltetrakis (3-laurylthiopropionate), ditridecyl 3,3'-thiodipropionate, 2-mercaptobenzimidazole And organic sulfur-based peroxide decomposers.

The light shielding agent is a component for preventing light from reaching the polymer bulk. Specific examples thereof include rutile titanium oxide (TiO2), zinc oxide (ZnO), chromium oxide (Cr2O3), cerium oxide (CeO2), and the like. The metal deactivator is a component for deactivating heavy metal ions in the resin by a chelate compound. Specific examples include acid amine derivatives, benzotriazoles, and derivatives thereof.

The quencher is a component for inactivating functional groups such as photo-excited hydroperoxides and carbonyl groups in the polymer by energy transfer, and organic nickel and the like are known. Examples of the apparatus for producing the resin composition of the present invention include an extruder, a Banbury mixer, a normaler, and a kneader. At that time, antioxidants, ultraviolet absorbers, tin-based heat stabilizers, inorganic and halogen-based flame retardants, lubricants such as stearic acid and zinc stearate, fillers, reinforcing agents such as glass fibers, dyes and pigments, etc. Coloring agents can be added as needed. By subjecting the composition of the present invention thus obtained to, for example, injection molding or extrusion molding, a molded article excellent in moldability (fluidity), heat resistance and impact resistance can be obtained.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to examples, but these do not limit the scope of the present invention. Methods for measuring physical properties and resins used in Examples and Comparative Examples will be described. (1) Izod impact strength Measured at 23 ° C. by a method according to ASTM-D256. (V notch, 1/4 inch test piece) (2) Measured by a method based on HDT ASTM-D648. (1/8 inch thickness of test piece, load 18.6kg / cm ² and 4.6kg / cm
² ) (3) Method of measuring falling weight impact strength.

A graphic impact tester type A (Toyo Seiki) was used as a measuring instrument. the detail is right below. Sample test piece: 1/8 inch Injection molded plate Missile diameter: 13Φmm Sample folder diameter: 40mm Missile drop height: 1m (4) Kerosene immersion test.

After the dumbbell pieces were immersed in kerosene at room temperature for 10 days, changes in the surface appearance and the occurrence of cracks were visually determined. No change: ○, small change: Δ, large change or crack occurrence:
× (A) Aromatic polycarbonate Commercially available bisphenol A-type polycarbonate (manufactured by Sumitomo Dow) Co. Caliber 200-3 was used. (Hereinafter referred to as PC) (B) Hydrogenated styrene-based elastomer The following hydrogenated styrene-based elastomer was used.

[0026]

[Table 1]

The following (C) styrene-acrylonitrile copolymer was used. (C-1) AS resin containing 6% acrylonitrile A mixed solution of 74.0% styrene, 6.0% acrylonitrile, 20.0% ethylbenzene and t-butylperoxyisopropyl carbonate as a polymerization catalyst A mixed solution containing 0.02 parts by weight per 100 parts by weight was added to 1.9.
The reactor was supplied at a rate of 1.2 liter / HR to a complete liter reactor, polymerized at a polymerization temperature of 140 ° C., and the polymerization solution was heated to 220 ° C. (solid content in the polymerization solution was 34% by weight). The mixture was introduced into an extruder, and the unreacted monomer and solvent were separated by evaporation to obtain a polymer. AN in copolymer
% Was 13% by weight (the amount of nitrogen was analyzed by elemental analysis and calculated from the amount of nitrogen). The solution viscosity (25 ° C.) of the polymer dissolved in methyl ethyl ketone was 8.7 cps. (C-2) AS resin containing 4.2% by weight of acrylonitrile C-2 was obtained according to the method for producing C-1 described above. (C-3) AS resin containing 20% by weight of acrylonitrile Stylac AS resin 8707 (manufactured by Asahi Chemical Industry) (D) Polyphenylene ether resin The following polyphenylene ether was used. (Less than
The inside of a stainless steel reactor having an oxygen blowing port at the bottom of the reactor and having a cooling coil and stirring blades inside was sufficiently replaced with nitrogen, and then 54.8 g of cupric bromide and di-n 8.75 kg of 2,6-xylenol was dissolved in a mixed solvent of 1110 g of -butylamine, 20 liters of toluene, 16 liters of n-butanol, and 4 liters of methanol, and charged into the reactor. While stirring, oxygen was continuously blown into the reactor, and polymerization was carried out for 180 minutes while controlling the internal temperature to 30 ° C. After the polymerization was completed, the precipitated polymer was separated by filtration, a mixed solution of methanol / hydrochloric acid was added thereto, the catalyst remaining in the polymer was decomposed, and the polymer was sufficiently washed with methanol and dried.
A powdered polyphenylene ether was obtained. Reduced viscosity ηs
p / C was 0.55 dl / g (chloroform). (Others) Rubber Reinforced Styrene Resin A commercially available rubber reinforced styrene resin (Asahi Kasei polystyrene resin H8117, hereinafter referred to as HIPS) was used.

[0028]

Examples 1 to 8, Comparative Examples 1 to 4 PC,
After blending HIPS, AS, PPE, SPS, and HTR, use a vented twin-screw extruder to obtain a resin temperature of 280 to 300 ° C.
And the mixture was pelletized. The obtained composition was injection molded at a resin temperature of 280 ° C. and a mold temperature of 110 ° C. to prepare a test piece, which was evaluated for physical properties. The results are shown in the table.

In Comparative Example 1 of the present invention, high impact polystyrene was used as a rubber component instead of the hydrogenated styrene elastomer as the component (B) of the present invention. Comparative Example 2 shows that if the acrylonitrile content in the styrene-acrylonitrile copolymer as the component (C) of the present invention is out of the range of the present invention, the impact resistance of the composition is significantly reduced. . Comparative Examples 3 and 4 show that the effects of the present invention cannot be achieved when the components (C) and (D) in the composition of the present invention are missing.

[0030]

[Table 2]

[0031]

[Table 3]

Claims (2)

[Claims] (A) an aromatic polycarbonate resin,
(B) hydrogenated styrene elastomer, (C) average 2
A copolymer resin of a vinyl cyanide-containing aromatic vinyl monomer and vinyl cyanide monomer of １５15% by weight,
The copolymer resin comprises: a) a vinyl cyanide content of 2 to 5;
B) 5 to 50% by weight of a copolymer having a vinyl cyanide content of 5 to 10% by weight, c)
Copolymer having a vinyl cyanide content of 10 to 15% by weight
(D) a polyphenylene ether resin, which is a copolymer resin of an aromatic vinyl monomer and a vinyl cyanide monomer, which is a mixture of 50% by weight (a total of 100% by weight of (a) + b) + c). Resin composition. 2. The hydrogenated styrenic elastomer according to claim 1, wherein the amount of bound styrene is from 50% by weight to 75% by weight.
2. The resin composition according to claim 1, wherein at least one kind is used, and at least one kind is used at least 10% by weight and less than 50% by weight.