JPH0621199B2 - Thermoplastic resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a novel thermoplastic resin composition, more specifically,
Thermoplastic resin composition mainly composed of polyolefin, which has sufficient mechanical properties such as heat resistance, rigidity and impact resistance, especially low temperature impact strength, and has good solid phase adhesion and is suitable as an industrial material Is.

[Prior Art] Conventionally, polyolefin resins have been widely used in many industrial fields because of their excellent mechanical strength, moldability, chemical resistance, and the like. However, since this polyolefin resin is non-polar, it has a drawback in that it is inferior in secondary processability, particularly in solid-phase adhesiveness, and it is inevitable that its application is limited.

Therefore, in order to improve such a defect, various methods have hitherto been used, for example, a method of blending polypropylene with a polymer having a good adhesive property (JP-A-48-63441).
Japanese Patent Publication No. 52-8134) and a method of blending polypropylene with polystyrene and an elastomer (JP-A-52-141854, JP-A-5-134854).
6-38338, JP-A-56-104978, JP-B-52-17055) and the like are proposed. However, in the method of blending a polymer having good adhesiveness, although the solid-phase adhesiveness is improved to some extent, the compatibility is poor and the physical properties are unavoidably deteriorated, and phase separation easily occurs in the molded product. There is a drawback of. Further, the method of blending polystyrene and an elastomer in combination brings about unfavorable situations such as drastically reduced fluidity, heat resistance and rigidity, and is not sufficient as an industrial material.

[Problems to be Solved by the Invention] Under such circumstances, the present invention is directed to heat resistance, rigidity,
Impact resistance In particular, mechanical properties such as low temperature impact strength are sufficiently retained, solid phase adhesion is good, and it is made for the purpose of providing a thermoplastic resin composition mainly composed of polyolefin suitable as an industrial material. It is a thing.

[Means for Solving the Problems] As a result of intensive studies to develop a thermoplastic resin composition having the above-described preferable properties, the present inventors have found that a polyolefin resin is modified with a rubber having a specific rubber dispersion form. It has been found that the object can be achieved by a composition in which a styrene resin and a compatibilizer are blended in a specific ratio, and the present invention has been completed based on this finding.

That is, the present invention relates to (A) polyolefin resin 50 to
5 to 40 parts by weight of the (C) compatibilizer with respect to 100 parts by weight of a resin mixture of 95% by weight and (B) 50 to 5% by weight of a rubber-modified styrenic resin in which the dispersed rubber form has an occlusion structure of 70% or more. To provide a thermoplastic resin composition.

Hereinafter, the present invention will be described in detail.

Examples of the polyolefin resin used as the component (A) in the composition of the present invention include α, such as ethylene, propylene, butene-1, 3-methylbutene-1, 3-methylpentene-1, and 4-methylpentene-1. Examples thereof include olefin homopolymers, copolymers thereof, and copolymers of these with other copolymerizable unsaturated monomers. As typical examples, high density, medium density, low density polyethylene and linear low density polyethylene, ultra high molecular weight polyethylene, ethylene-polyethylene such as vinyl acetate copolymer, ethylene-ethyl acrylate copolymer,
Propylene homopolymer, propylene-ethylene block copolymer and random copolymer, propylene-ethylene-
Examples thereof include polypropylenes such as diene compound copolymers, polybutene-1, poly-4-methylpentene-1, and the like. Among these, crystalline polyethylene and crystalline polypropylene are preferable, and crystalline polypropylene is particularly preferable. Is preferred.

As the crystalline polypropylene, for example, an isotactic propylene homopolymer having crystallinity, a copolymerization part composed of an ethylene-propylene random copolymer having a low content of ethylene units or a homopolymerization part composed of a propylene homopolymer, A block copolymer of substantially crystalline propylene and ethylene, which is commercially available as a so-called propylene block copolymer, which is composed of a copolymerization part composed of an ethylene-propylene random copolymer having a relatively large content of ethylene units. A substantially crystalline propylene-ethylene-α-olefin copolymerization product, in which each homopolymerization part or copolymerization part in this block copolymer is further copolymerized with an α-olefin such as butene-1. Preference is given to coalescing.

The polyolefin resin used as the component (A) preferably has a melt index (MI) in the range of 5 to 60 g / 10 minutes. If the MI is less than 5 g / 10 minutes, the moldability is poor, and if it exceeds 60 g / 10 minutes, the impact resistance tends to decrease. The polyolefin resin may be used alone or in combination of two or more.

In the composition of the present invention, as the component (B), a rubber-modified styrene resin whose dispersed rubber form has an occlusion structure of 70% or more is used. The term “occlusion structure” as used herein means that one rubber particle contains 5 or less inclusion occlusions in which the core is a styrene-based polymer and the shell is a rubber-like polymer, and at least 5 of them are included.
0% refers to a structure with one inclusion occlusion.

The rubber-modified styrenic resin as the component (B) is required to have a dispersed rubber form having an occlusion structure of 70% or more as described above, and if particles such as a salami structure are mixed in an amount of 30% or more, the object of the present invention is Can't reach enough. Therefore, in the present invention, impact-resistant polystyrene (HIPS) having a normal salami structure containing 6 or more inclusion occlusions may be blended as long as the proportion of rubber particles is less than 30%.

The rubber-modified styrenic resin has an occlusion structure having a symmetry plane, and has an area average particle diameter of 0.1 to 0.1.
0.7 μm, preferably 0.2 to 0.6 μm, and the ratio of the area average particle diameter to the number average particle diameter is 1.0 to 2.5,
Preferably, rubber polymer particles in the range of 1.0 to 1.8 are dispersed in a styrene resin. Further, as the rubber-modified styrene resin, the volume fraction (φ _R ) of the rubber-like polymer particles, the area average particle diameter (diameter) (D _S ) of the rubber-like polymer particles, and the thickness of the rubber-like polymer phase relation to the (lambda) factor K = φ _R {1 - _{[[(D S} / 2) -λ] / _{(D S} /
2)] ³ } ⁻¹ (I) (where λ is 0.10 μm or less), the K is 0.18 or more, preferably 0.20 or more, more preferably 0.22 or more. It is suitable.

The volume fraction of the particles of the rubbery polymer (phi _R) of the formula _{φ R = {[1 / W} R) -1] (ρ R / ρ PS) 1) -1 ... (I
I) can be sought by.

Here, ρ _R is the specific gravity of the rubber-like polymer and is used at 0.90. Or ρ _PS is the specific gravity of the styrene polymer,
1.05 is used. More W _R in a weight fraction of the rubber-like polymer contained in the rubber-modified styrene resin, wherein Can be found at.

Area average particle diameter of the rubber-like polymer particles (diameter) (D _S) and (D _n) may be obtained as follows. That is, pellets of rubber-modified styrenic resin having a small orientation were treated with a 3% by weight aqueous solution of osmium tetroxide and thinned with an ultramicrotome. By measuring the diameter (D) of the polymer particles in the major axis direction with respect to 1000 particles, and obtaining the area average value according to the following formula,
Area average particle diameter of the rubber-like polymer particles (diameter) _{(D S)} and _{(D n)} is obtained.

(N is the number of rubber-like polymer particles having a diameter D) Further, the thickness (λ) of the rubber-like polymer phase was obtained in the same manner as above, and a transmission electron microscope image was obtained.
A rubbery polymer phase exists only in the periphery, that is,
The thickness λi of the rubber-like polymer phase of the rubber-like polymer particles cut near the center is measured for 100 particles, and the number average value thereof is obtained according to the following equation.

λ = (λ ₁ + λ ₂ + λ ₃ + ... + λ ₁₀₀ ) / 100 Similarly, a transmission electron microscope image is obtained, and the ratio of the number of occlusion structure particles to 1000 randomly extracted particles is calculated. The ratio of occlusion structure particles was evaluated.

In the rubber-modified styrene resin, the rubber polymer particles preferably have a specific microstructure. That is, it is desirable that the gel amount is in the range of 1.1 to 4.0 weight ratio, preferably 1.4 to 3.6 weight ratio with respect to the rubber-like polymer, and the swelling index thereof is 5 to 20, It is preferably in the range of 7 to 18.

By using a rubber-modified styrene resin satisfying the above-mentioned conditions as the component (B), the object of the present invention can be achieved more effectively.

In the rubber-modified styrene resin, the styrene polymer and the rubber-like polymer are 70 to 92% by weight and 3%, respectively.
0-8% by weight, preferably 72-90% by weight and 28-
It is desirable to contain it in a ratio of 10% by weight. If the content of the rubber-like polymer is less than 8% by weight, the effect of improving impact resistance is not sufficiently exerted, and if it exceeds 30% by weight, the fluidity tends to decrease.

Further, in the rubber-modified styrene resin, the thickness (λ) of the rubber-like polymer phase is preferably 0.10 μm or less. In order for the thickness (λ) of the rubber-like polymer phase to be 0.10 μm or more, it is necessary to increase the molecular weight of the rubber-like polymer used (for example, styrene-butanediene-based block copolymer rubber is used). When used, the butanediene polymer block portion needs to have a molecular weight of about 800,000 or more).

When a rubber-modified styrene resin is produced using such a high molecular weight rubber-like polymer, the viscosity of the polymerization reaction solution becomes extremely high, which is not preferable. The thickness (λ) of the rubbery polymer phase is preferably 0.005 to 0.07 μm.

The rubber-modified styrene resin as the component (B) can be prepared by polymerizing styrene or a monomer copolymerizable with styrene in the presence of a rubber-like polymer. Examples of the monomer copolymerizable with styrene include α
-Methylstyrene, vinyltoluene, vinylethylbenzene, vinylxylene, pt-butylstyrene, α-
Examples thereof include aromatic monovinyl compounds such as methyl-p-methylstyrene and vinylnaphthalene, acrylonitrile, methyl methacrylate, methyl acrylate, methacrylic acid, acrylic acid, maleic anhydride, and phenylmaleimide. These monomers may be used alone or in combination of two or more, and usually 50% by weight or less, preferably 40% by weight or less based on the total monomers containing styrene. Used in proportion.

On the other hand, the type of rubber-like polymer is not particularly limited,
Although conventionally used for rubber-modified styrenic resins,
For example, natural rubber, synthetic rubber such as polybutadiene rubber, polyisoprene rubber, styrene-butadiene copolymer rubber, styrene-isoprene copolymer rubber, butyl rubber, ethylene-propylene copolymer rubber, or these rubbers Graft copolymer rubbers with styrene and the like can be used, and among these, styrene-butadiene block copolymer rubbers are preferable. The styrene-butadiene block copolymer rubber has a molecular weight in the range of 50,000 to 500,000, and the content of the polymer block formed by styrenes is 1
Those in the range of 0 to 60% by weight are particularly preferable. If the molecular weight is less than 50,000, the impact resistance is not sufficient, and if it exceeds 500,000, the fluidity at the time of molding tends to decrease, which is not preferable. In addition, the styrene-butadiene block copolymer rubber has a molecular weight of 5
About 50,000 to 500,000 polybutadiene rubber may be appropriately mixed and used.

The polymerization method is not particularly limited, and a conventionally used method such as an emulsion polymerization method, a bulk polymerization method, a solution polymerization method,
A suspension polymerization method or a multi-stage polymerization method such as a bulk-suspension two-stage polymerization method can be used.

Next, one example of a preferred method for producing a rubber-modified styrene resin by the bulk-suspension two-stage polymerization method will be described. First, styrene or a mixture of styrene and a monomer copolymerizable with styrene is added to a rubber-like polymer. Is added and, if necessary, heated to dissolve. It is preferable that this dissolution be performed as uniformly as possible.

Next, to this solution, a molecular weight regulator (chain transfer agent) such as alkyl mercaptan and a polymerization initiator such as an organic peroxide used as necessary are added, while heating to a temperature of about 70 to 150 ° C., Preliminary polymerization by the bulk polymerization method is carried out with stirring until the degree of polymerization reaches 10 to 60%. In this prepolymerization step, the rubbery polymer is dispersed into particles by stirring.

Then, the prepolymerized solution is suspended in an aqueous phase using tricalcium phosphate or polyvinyl alcohol as a suspending agent,
Usually, suspension polymerization (main polymerization) is performed until the degree of polymerization approaches 100%. After the main polymerization step, if necessary,
Further heating may be continued.

Examples of the molecular weight modifier include mercaptans such as α-methylstyrene dimer, n-dodecyl mercaptan, t-dodecyl mercaptan, 1-phenylbutene-2-fluorene, dipentene and chloroform, terpenes, halogen compounds and the like. You can

Examples of the polymerization initiator used as desired include 1,1-bis (t-butylperoxy) cyclohexane and 1,1-bis (t-butylperoxy) -3,3,5.
-Peroxyketals such as trimethylcyclohexane, dicumyl peroxide, di-t-butyl peroxide, dialkyl peroxides such as 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, benzoyl peroxide, m-toluene Diaryl peroxides such as oil peroxides, peroxydicarbonates such as dimyristyl peroxydicarbonate, t
Examples thereof include peroxyesters such as -butylperoxyisopropyl carbonate, ketone peroxides such as cyclohexanone peroxide, and organic peroxides such as hydroperoxides such as p-menthane hydroperoxide.

The thickness λ of the rubber-like polymer phase can be controlled by changing the molecular weight of the butadiene polymer block portion when using, for example, a styrene-butadiene block copolymer rubber as the rubber-like polymer. . That is, when the molecular weight of the butadiene polymer block portion is reduced, λ is decreased, and when it is increased, λ is increased. On the other hand, the radius R of the rubber-like polymer particles depends on the stirring speed during the polymerization, the molecular weight of the styrene polymer block portion when a styrene-butadiene block copolymer rubber is used as the rubber-like polymer, and the chain transfer agent. It can be controlled by the presence or absence, the presence or absence of polybutadiene rubber blended with the styrene-butadiene block copolymer rubber, and the like. That is,
R decreases when the stirring speed during the polymerization is fast, and increases when the stirring speed is slow. When the molecular weight of the styrene polymer block part is increased, R is decreased, and when it is decreased, R is increased. In addition, R is small when a chain transfer agent is not used, but increases when it is used, and when polybutadiene rubber is used, R increases,
R is small when not used.

Next, the slurry thus obtained is treated by a conventional means to take out the beaded reaction product, which is dried and then pelletized according to a conventional method to obtain a desired rubber-modified styrene resin. To be The molecular weight of the matrix portion of the rubber-modified styrenic resin thus obtained is 100,000 to 300,000, preferably 13
Advantageously, it is in the range of 20,000 to 280,000. If the molecular weight is less than 100,000, the impact resistance will be poor, and if it exceeds 300,000, the fluidity during molding will be insufficient.

In the composition of the present invention, the blending ratio of the polyolefin resin as the component (A) and the rubber-modified styrenic resin as the component (B) is based on the total weight of the component (A) and the component (B) ( It is necessary that the component (A) is 50 to 95% by weight, preferably 60 to 85% by weight, and the component (B) is 50 to 5% by weight, preferably 40 to 15% by weight. If the content of the component (A) is less than 50% by weight, the moldability may be poor, and if it exceeds 95% by weight, the rigidity tends to decrease.

In the composition of the present invention, a compatibilizer is used as the component (C). The compatibilizing solvent is not particularly limited as long as it has a property of compatibilizing the polyolefin resin and the rubber-modified styrene resin. Examples of the compatibilizer include styrene-based thermoplastic elastomers such as styrene-butadiene copolymers and styrene-isoprene copolymers, acrylic thermoplastic elastomers, ethylene-ethyl acrylate-maleic anhydride copolymers, and the like. . By using such a compatibilizing agent, the rubber-modified styrenic resin is extremely homogeneously dispersed in the polyolefin resin, and a composition having excellent physical properties can be obtained.

In the composition of the present invention, one type of these compatibilizers may be used, or two or more types may be used in combination, and the compounding amounts thereof are the polyolefin resin of the component (A) and the component (B). Of rubber-modified styrene resin
5 to 40 parts by weight, preferably 10 to 35 parts by weight
It is selected within the range of parts by weight. If this amount is less than 5 parts by weight, the impact resistance is poor, and if it exceeds 40 parts by weight, the rigidity tends to decrease.

In the composition of the present invention, various known additive components, such as calcium carbonate, may be added as necessary within a range not impairing the object of the present invention.
Addition of inorganic fillers such as talc, mica, silica, asbestos, reinforcing agents such as glass fiber, carbon fiber, metal whiskers, antioxidants, UV absorbers, heat stabilizers, lubricants, hardeners, antistatic agents, etc. May contain an agent, also other thermoplastic resins, for example polyvinyl chloride resin, polyamide resin, polyimide resin, polyester resin, polycarbonate resin, polyacetal resin,
You may mix | blend polyaromatic ether ketone type resin, polyphenylene ether type resin, polyphenylene sulfide type resin, polyaromatic ester type resin, polysulfone type resin, other styrene type resin, acrylate type resin, etc.

The composition of the present invention is, for example, the above-mentioned component (A), component (B),
The component (C) and various additives used as necessary are blended in predetermined proportions, and then mixed with a Banbury mixer, a single-screw extruder, a twin-screw extruder, a co-kneader, a multi-screw extruder, etc. ~ 2
It can be prepared by sufficiently kneading at a temperature in the range of 40 ° C.

The composition of the present invention thus obtained can be molded into a molded product having a desired shape according to a commonly used method such as an injection molding method or an extrusion molding method.

EXAMPLES Next, the present invention will be described in more detail with reference to Examples.
The invention is in no way limited by these examples.

The physical properties of the rubber-modified polystyrene and the resin composition were determined as follows.

(1) Gel amount, swelling index Sample Wc (g) was dissolved in toluene and
After centrifuging at pm for 60 minutes, the supernatant was decanted to obtain the swollen insoluble component amount Ws (g), and then the swollen insoluble component was vacuum dried at 60 ° C. for 24 hours to obtain a dry insoluble component amount. Wg (g) is calculated.

Gel amount (wt%) = (Wg / Wc) × 100 Swelling index = Ws / Wg (2) Glossiness It was determined according to JIS K-7105.

(3) Izod impact strength It was determined in accordance with JIS K-7110. In the case of rubber-modified polystyrene, it was determined at 23 ° C. under notched conditions, and for the composition, it was determined at −30 ° C. under notched conditions.

(4) Heat distortion temperature It was determined according to JIS K-7102.

(5) Flexural modulus It was determined according to ASTM D-790.

(6) Melt index [MI] Obtained in accordance with ISO R-1133.

(7) Drop weight impact strength (a) In the case of rubber-modified polystyrene A load of 3 at the center of the plate width (70 mm) at 125 mm from the gate position (end of the molded plate) of the 270 x 70 x 3 mm injection molded plate. Measured using an automatic falling weight impact tester RDT5000 manufactured by Rheometrics under the conditions of 0.76 kg, speed 3.5 m / sec, hole diameter of sample fixing part 2 inch, temperature 23 ° C. The energy up to the point when the force suddenly decreased was calculated and used as the falling weight impact strength.

(B) Composition: In the above method, the speed is 11 m / sec and the temperature is -30 ° C.
The drop weight impact strength was determined in the same manner except that

Production Example 1 Production of single occlusion rubber-modified polystyrene An autoclave having an internal volume of 5 has a weight average molecular weight of 100,000,
SB block copolymer having a styrene unit content of 22.6% by weight [Nippon Zeon Co., Ltd., trade name: ZLS-01]
659 g, styrene 3000 g and n-dodecyl mercaptan 1 g as a chain transfer agent were added, and the reaction was carried out at 130 ° C. for 4 hours while stirring at 300 rpm.

The reaction mixture 30 was then added to 10 autoclaves.
00g, water 3000g, polyvinyl alcohol 10g as a suspension stabilizer, benzoyl peroxide 6g and dicumyl peroxide 3g as a polymerization initiator
While stirring at 00 rpm, the temperature was raised from 80 ° C. to 140 ° C. at a heating rate of 30 ° C./hr, and the reaction was continued at that temperature for 4 hours to obtain rubber-modified polystyrene beads.

Next, the obtained beads were pelletized by a single-screw extruder at 220 ° C. and then molded.

Table 1 shows the measurement results of the physical properties of the obtained molded product and the properties of the rubber-modified polystyrene.

Production Example 2 Production of single occlusion rubber modified polystyrene SB block copolymer [manufactured by Nippon Zeon Co., Ltd., trade name: ZLS-01, content of styrene unit 22.6% by weight, molecular weight 10] in an autoclave with an internal capacity of 5 10,000] 704
g, styrene 3000 g, and n-dodecyl mercaptan 1 g as a chain transfer agent were added, and the reaction was carried out at 130 ° C. for 4 hours while stirring at 300 rpm to obtain a prepolymer (I).
Got

Similarly, a prepolymer (II) was obtained by using 409 g of polybutadiene (trade name: NF35AS, manufactured by Asahi Kasei Co., Ltd.) and 1 g of n-dodecyl mercaptan (the rubber structure was prepared under the following suspension polymerization conditions. The beads were synthesized and the occlusion of 0.4 μm and 1.
A salami structure of 2 μm was confirmed). Then, 2550 g of the prepolymer (I) obtained in the autoclave of 10,
Prepolymer (II) 450 g, water 3000 g, polyvinyl alcohol 10 g as a suspension stabilizer, benzoyl peroxide 6 g and dicumyl peroxide 3 g as a polymerization initiator were added, and the mixture was stirred at 500 rpm while stirring at 80 ° C. to 30 ° C./hour. The temperature was raised to 140 ° C. and the reaction was continued for 4 hours to obtain rubber-modified polystyrene beads (occlusion was 0.4 μm, salami was 1.2 μm was confirmed by an electron microscope). The obtained beads were pelletized by a single-screw extruder at 220 ° C. and then molded.

Table 1 shows the measurement results of the physical properties of the obtained molded product and the properties of the rubber-modified polystyrene.

Example 1 15 parts by weight of rubber-modified polystyrene having an occlusion structure obtained in Production Example 1, block polypropylene (MI
10) 85 parts by weight and SBS (styrene-butadiene-styrene copolymer as a compatibilizer, manufactured by Shell Chemical Co.,
After 12 parts by weight of Califlex TR1102) was dry blended, pellets were obtained by kneading using a single-screw kneader at a temperature of 200 ° C. and a rotation speed of 80 rpm.

Next, a test piece was prepared by injection molding using this pellet, and the Izod impact strength, falling weight impact strength, flexural modulus, and heat deformation temperature were determined. The results are shown in Table 2.

Example 2 In Example 1, the block polypropylene and the rubber-modified polystyrene obtained in Production Example 1 were mixed in amounts of 7 and 7, respectively.
The same operation as in Example 1 was performed except that the amount was changed to 0 parts by weight and 30 parts by weight. The results are shown in Table 2.

Example 3 The same operation as in Example 1 was performed except that SEBS (hydrogenated SBS, manufactured by Shell Chemical Co., Ltd.) was used in place of SBS. The results are shown in Table 2.

Example 4 The same operation as in Example 1 was performed except that the rubber-modified polystyrene obtained in Production Example 1 was replaced with the rubber-modified polystyrene obtained in Production Example 2. The results are shown in Table 2.

Example 5 The same operation as in Example 3 was performed, except that the rubber-modified polystyrene obtained in Production Example 1 was replaced with the rubber-modified polystyrene obtained in Production Example 2. The results are shown in Table 2.

Comparative Example 1 In Example 1, instead of the rubber-modified polystyrene obtained in Production Example 1, rubber-modified polystyrene “Idemitsu Styrol H” was used.
T-51 "(MI2.0 manufactured by Idemitsu Petrochemical Co., Ltd.) was used, and the same operation as in Example 1 was performed. The results are shown in Table 2.

Comparative Example 2 In Example 2, instead of the rubber-modified polystyrene obtained in Production Example 1, rubber-modified polystyrene “Idemitsu Styrol H” was used.
The same operation as in Example 2 was performed except that "T-51" was used. The results are shown in Table 2.

[Effect of the Invention] The thermoplastic resin composition of the present invention comprises a polyolefin resin, a rubber-modified styrenic resin having an occlusion structure in a dispersed rubber state, and a compatibilizer, and heat resistance and rigidity, Impact resistance In particular, mechanical properties such as low temperature impact strength are sufficiently retained, and solid phase adhesion is good, and it is suitably used as an industrial material such as an outer panel in the field of automobiles.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical display location C08L 25/04 LDX 9166-4J 51/04 LKY 7142-4J 53/00 LLY 7142-4J

Claims (3)

[Claims] 1. A polyolefin resin of 50 to 95% by weight and (B) a dispersed rubber form having an occlusion structure of 70%.
With respect to 100 parts by weight of a resin mixture with 50 to 5% by weight of the rubber-modified styrenic resin, the (C) compatibilizer 5 to
A thermoplastic resin composition comprising 40 parts by weight. 2. A rubber-modified styrenic resin comprising a rubber-like polymer having an occlusion structure having a plane of symmetry, having an area average particle diameter of 0.1 to 0.7 μm, and having an area average with respect to a number average particle diameter. The thermoplastic resin composition according to claim 1, which is dispersed in a styrene polymer as particles having a particle diameter ratio of 1.0 to 2.5. Wherein the dispersed particles of the rubber-like polymer, relationship K = φ _R {1 - _{[[(D S} / 2) -λ] / _{(D S} /
2)] ³ } ^-1 (in the formula, φ _R represents the volume fraction of the rubber-like polymer in the rubber-modified styrene resin, D _S represents the area average particle diameter (diameter) of the rubber-like polymer, λ is the thickness of the rubber-like polymer and is 0.1
It is 0 μm or less. The thermoplastic heavy composition according to claim 2, wherein K determined in (4) is 0.18 or more.