KR20030005981A - Heat Resistance Thermoplastic Resin Composition Having Good Surface Property - Google Patents

Abstract

PURPOSE: Provided is a heat resistant, anti-conductive and thermoplastic resin composition containing ABS resin grafted with two different particle size rubber polymers. The small particle size rubber gives good appearance and the middle particle size rubber balances the physical properties. CONSTITUTION: The composition comprises: (A) 20-60wt.% ABS resin consisting of (a1) a graft polymer using the rubber of 0.08-0.18micrometer average particle size and (a2) a graft polymer using the rubber of 0.28-0.38micrometer average particle size, in the weight ratio of 40:60-80:20; (B) 80-40wt.% SAN resin composed of (b1) 30-90wt.% of AMS-based heat resistant SAN resin containing 65-78wt.% of α -methylstyrene and 35-22wt.% of acrylonitrile and (b2) 70-10wt.% of SAN resin with molecular weight of 80,000-120,000 containing 65-78wt.% of styrene and 35-22wt.% of acrylonitrile. On the basis of 100wt.% of above resin composition (A) and (B), the composition optionally comprises (C) 0.1-2.0wt.% of silicon graft copolymer composed of 65-40wt.% of vinyl graft copolymer containing (c1) 35-60wt.% of silicon copolymer with the particle size of 200-400micrometer and (c2) 40-90wt.% of aromatic styrene and 60-10wt.% of vinyl graft copolymer; (D) 0.1-2.0wt.% of heat stabilizer; (E) 0.2-2.0 wt.% of lubricant; (F) and/or 0.4-2.0wt.% of anti-static agent.

Description

Heat Resistance Thermoplastic Resin Composition Having Good Surface Property

Field of invention

The present invention relates to a heat resistant thermoplastic resin composition excellent in appearance quality. More specifically, the present invention consists of a mixture of graft ABS polymers and SAN resins polymerized separately from two rubber polymers having different particle diameters, and optionally further comprises a silicone-based graft copolymer, a heat stabilizer, a lubricant and an antistatic agent. It relates to a heat resistant thermoplastic resin composition comprising.

Background of the Invention

Generally, the ABS resin obtained by graft copolymerization of a butadiene-based rubber polymer with an aromatic vinyl monomer represented by styrene and an unsaturated nitrile monomer represented by acrylonitrile has excellent impact resistance, processability, and excellent mechanical strength. It is widely used in automobile parts and office equipment. However, since ABS resins are not as heat resistant as engineering plastics, their use is limited to parts of electronic products, automotive interiors, and the like that require heat resistance.

In order to impart heat resistance to such ABS resin, not only general SAN resin but also AMS heat resistant SAN resin in which styrene is replaced with α-methyl styrene as a matrix, or PMI resin based on vinyl monomer and maleimide monomer are used together. Doing. However, the ABS resins manufactured in this way are suitable for the application of electronic interior materials or automobile parts that do not require high-end appearance because they satisfy mechanical strength and heat resistance, but the colorability and surface gloss of the final molded products are deteriorated, which is comparable to that of electronic products. It does not satisfy the needs of modern consumers who demand beautiful designs and colors. In particular, in order to be used for the exterior of electronic products such as a white heating current such as a microwave oven, an electric wiring device, a drum type washing machine, fluidity, heat resistance, and antistatic property are required at the same time.

In order to obtain an ABS resin having excellent glossiness, a method of increasing the content of the SAN resin mixed with the ABS resin or reducing the particle size of the rubbery polymer required for the production of the ABS resin has been proposed.

However, if the balance is not maintained, the impact resistance of the product is significantly lowered, and there is a problem in that cracks are generated during assembly of the molded article. In particular, in the case where a heat resistant SAN resin is used as the matrix SAN resin, the heat resistant SAN resin has a brittle property and the phenomenon is further intensified.

In contrast, the present inventors separately prepared a graft ABS resin polymerized using a small particle rubbery polymer and a polymerized graft ABS resin using a medium particle rubbery polymer in order to overcome the above problems, and mixed them in a constant ratio. By using it, it has excellent balance of physical properties including surface gloss and has excellent appearance. Also, in the application of SAN resin, by using AMS-based heat-resistant SAN resin and low-molecular weight SAN resin, it is possible to develop a thermoplastic resin composition having excellent fluidity and heat resistance. It is early.

An object of the present invention is to provide a thermoplastic resin composition having excellent appearance quality including surface gloss.

Another object of the present invention is to provide a thermoplastic resin composition having excellent heat resistance.

Still another object of the present invention is to provide a thermoplastic resin composition having excellent flowability.

Still another object of the present invention is to provide a thermoplastic resin composition having excellent mechanical strength.

Still another object of the present invention is to provide a thermoplastic resin composition having excellent antistatic property.

Still another object of the present invention is to provide a thermoplastic resin composition that satisfies the above properties at the same time and is suitable as a packaging material for high-grade electrical appliances.

The above and other objects of the present invention can be achieved by the present invention described below.

The heat-resistant thermoplastic resin composition of the present invention is composed of (A) 20-60% by weight ABS resin, (B) 80-40% by weight SAN resin, and optionally with respect to 100 parts by weight of the (A) + (B) resin, (C) 0.1-2.0 parts by weight of the silicone graft copolymer, (D) 0.1-1.0 parts by weight of the heat stabilizer, (E) 0.2-2.0 parts by weight of the lubricant and (F) 0.4-2.0 parts by weight of the antistatic agent. . Detailed description of each of these components is as follows.

(A) ABS resin

ABS resin used in the present invention is (a ₁ ) graft polymer prepared by graft polymerization of small particle size rubber having an average particle size of 0.08-0.18㎛ and (a ₂ ) medium particle size having an average particle size of 0.28-0.38㎛ The graft polymer prepared by graft polymerization of rubber is mixed and used in a ratio of 40:60 to 80: 20% by weight based on 100% by weight of the total ABS resin.

The reason for mixing and using the graft polymers described above is that when the rubbery polymer having a thickness of 0.20 µm or less is used alone, the surface gloss is improved, but the impact resistance is remarkably lowered. This is because the impact resistance is improved, but the surface glossiness is significantly reduced.

Therefore, in order to compensate for these disadvantages and simultaneously obtain the properties of each rubbery polymer, a graft ABS resin using a rubbery polymer composed of small particles having an average particle diameter of about 0.08 to 0.18 μm and a large particle of about 0.28 to 0.38 μm It is preferable to mix and use the graft ABS resin using the rubbery polymer which consists of these.

If the different rubbery polymers are mixed before the graft polymerization and the ABS resin is subjected to the graft reaction, the impact resistance and glossiness cannot be improved at the same time. This is because the graft reaction is difficult to uniformly occur in each particle due to the difference in surface area per volume of the small rubber and the large rubber.

In addition, the first graft latex was prepared by first presenting a rubbery polymer latex having a small particle diameter in the graft polymerization system and graft polymerizing to an appropriate conversion rate by emulsion polymerization method, and then in the presence of the prepared primary graft latex. The ABS resin produced by completing the secondary graft reaction by adding a large amount of rubbery polymer latex and continuously adding the remaining graft monomer is suitable for the glossiness of the small particle rubber and the impact resistance of the medium particle rubber. Although it is possible to obtain a harmonized ABS resin, a large amount of unplasticized particles are generated during the polymerization process, causing surface defects of the final molded product.

Therefore, in the present invention, two kinds of rubber polymers having different rubber particle sizes are respectively graft-emulsified to separately prepare two kinds of ABS resins, which are mixed and used in the compounding process, thereby improving the appearance quality of the small particle rubber. In addition to physical properties such as impact resistance of the medium and large-sized rubber, the polymerization process is stabilized to minimize coagulaum and unplasticized particles.

The average particle diameter of the small particle size rubber | gum of the rubber which can be used for this invention shall be about 0.05-0.20 micrometer, Especially about 0.08-0.18 micrometer is preferable. Moreover, the average particle diameter of a medium particle size rubber shall be 0.25-0.40 micrometers, and about 0.28-0.38 micrometers is preferable.

The rubbery polymers having different particle sizes are each graft polymerized and used by mixing a small particle size: medium particle size graft polymer in a ratio of 40:60 to 80:20 parts by weight. If the ratio is out of the ratio, the characteristics of the rubbery polymers having the respective particle sizes may not be harmonized, and the surface gloss may be degraded by the small-diameter rubber, or may be broken by the small-diameter rubber.

It is preferable that the graft ratio of each said graft polymer shall be 40-90%. If the graft rate is lower than this, it is difficult to obtain a white powder having a uniform particle size distribution during solidification and drying, as well as fisheye, pinhole or sandsurface as unplasticized particles on the surface of the molded part during pressure and injection. ), The surface gloss is reduced. In addition, when the graft ratio exceeds 90%, physical properties such as impact strength, fluidity, and surface gloss decrease.

The ABS resin constitutes 20-60% by weight of the total base resin.

(B) SAN resin

The SAN resin used in the present invention improves the fluidity and heat resistance of the resin by simultaneously using (b ₁ ) 30-90% by weight of the AMS-based heat-resistant SAN resin and (b ₂ ) 70-10% by weight of the low molecular weight SAN resin. To act. The SAN resin constitutes 80-40% by weight of the total base resin.

(b ₁ ) AMS heat resistant SAN resin

The AMS heat-resistant SAN resin consists of 65-78 wt% of α-methylstyrene and 35-22 wt% of acrylonitrile. When the weight percent of α-methylstyrene is less than 65 weight percent, the heat deformation temperature of the heat resistant SAN resin is lowered, which causes the characteristics of the heat resistant SAN resin to disappear. In addition, the acrylonitrile content in the resin is more preferable than α-methylstyrene in molar parts, so that a large amount of the continuous chain of acrylonitrile is generated, causing coloring, which is not preferable.

When the α-methylstyrene content is 78% by weight or more, coloration in the resin does not occur, but the polymerization rate decreases rapidly, so that the remaining monomers in the heat-resistant SAN resin increase, so that the heat deformation temperature is lowered and the heat-resistant ABS product having excellent thermal stability This makes it difficult to apply.

(b ₂ ) low molecular weight SAN resin

The low molecular weight SAN resins used in the present invention are well known to those skilled in the art, and may be polymerized by suspension polymerization or bulk polymerization, and in particular, SAN resins prepared by bulk polymerization may be used. It is preferable.

When the additive content is high during the polymerization manufacturing process, it is easy to cause appearance defects such as bubbles in the molded article during injection molding, and when the gel is contained in the SAN resin, it protrudes on the surface of the final molded article to improve the quality of the molded article. Since there is a problem of lowering the amount of additives, SAN resin produced by the bulk polymerization method with less additive content and less gel generation is used.

The low molecular weight SAN resin is prepared by copolymerizing styrene 65-78 wt% and acrylonitrile 35-22 wt%, preferably having a weight average molecular weight of 80,000-120,000.

If the weight average molecular weight is 80,000 or less, there is a problem that the impact resistance is significantly lowered. If the weight average molecular weight is 120,000 or more, the fluidity is lowered, which may cause unmolding, poor bubble generation, etc. during injection molding of a complicated structure.

SAN resin of the present invention is composed of 30-90% by weight of the AMS-based heat-resistant SAN resin and 70-10% by weight of low molecular weight general SAN resin. If the content of the heat-resistant SAN resin is 30% by weight or less based on the total SAN resin 100, the heat resistance is not significantly different from the general ABS resin, it is not suitable for a molded article requiring heat resistance. In addition, when the low molecular weight SAN resin is 10% by weight or less based on the total SAN resin 100, the flow index is lowered, resulting in poor workability.

The ABS resin and the SAN resin is preferably mixed 20-60% ABS resin, 80-40% SAN resin. If the ABS resin content is 20% or less, it is difficult to obtain an ABS resin having excellent impact resistance required by the present invention, and at 60% or more, it is impossible to complete the present invention by lowering heat resistance and fluidity.

The heat-resistant thermoplastic resin composition of the present invention may be prepared by injection molding through a melt kneading process by further adding an impact modifier, a thermal stabilizer, a lubricant, and an antistatic agent to the ABS resin and the SAN resin as base resins. Can be.

(C) Silicone Graft Copolymer

In the present invention, silicone-based graft copolymers are used as optional components. The silicone graft copolymer serves to improve the impact resistance of the heat resistant thermoplastic resin composition of the present invention.

Silicone-based graft copolymer of the present invention is (c ₁ ) 35-60% by weight of the silicone-based rubbery polymer; And (c ₂ ) a core-shell copolymer obtained by graft polymerization of 40-40 wt% of an aromatic styrene monomer and 65-40 wt% of a vinyl-based graft copolymer including 60-10 wt% of an acrylonitrile monomer. In the above, the silicone-based rubbery polymer constitutes a core, and the vinyl-based graft copolymer composed of styrene and acrylonitrile monomer maintains mechanical strength by forming a shell.

When the amount of the silicone rubber polymer is 35% by weight or less, the hardness, tensile strength, flexural strength, and heat resistance of the resin are improved, but the impact resistance rapidly decreases. In addition, when the silicone rubber polymer is 60% by weight or more, the impact resistance is excellent, but there is a disadvantage in that the productivity is lowered and the strength of the resin composition is lowered.

The average particle size of the rubber particles of the silicone rubber polymer may be used 10-500㎛, in the present invention is preferably in the range of 200-400㎛. If the average particle size is 200 μm or less or 400 μm or more, there is little effect of improving the impact reinforcement through proper morphological control.

The silicone graft copolymer (C) is preferably used 0.1 to 2.0 parts by weight based on 100 parts by weight of the base resin mixed with ABS resin and SAN resin. When used in an amount of less than 0.1 parts by weight can not be expected to improve the impact resistance for the purpose of adding a silicone-based graft copolymer, when used in excess of 2.0 parts by weight can not be expected to improve the impact resistance further, there is a disadvantage that the manufacturing cost increases.

(D) heat stabilizer

In the production of the heat-resistant thermoplastic resin composition of the present invention, in order to prevent the oxidation phenomenon that may occur during the extrusion, injection molding and mixing the ABS resin and SAN resin, a heat stabilizer may be used. The heat stabilizer is used in the range of 0.1 to 2.0 parts by weight based on 100 parts by weight of the base resin.

In the present invention, the heat stabilizer is preferably used alone or a mixture of a phenolic heat stabilizer and a phosphite thermal stabilizer.

The phenolic heat stabilizer includes 2,6-di-thi-butyl-4-methylphenol, 2,2'-methylene-bis (4-methyl-6-ti-butyl) -phenol and the like.

When using a phenolic heat stabilizer independently, it is preferable to use it in the range of 0.1-1.0 weight part with respect to 100 weight part of base resins. In addition, when a phosphite-based heat stabilizer is used in combination with the phenolic heat stabilizer, it is advantageous for injection molding because it further enhances the heat stability. Diphenyl monooctyl phosphite is preferably used as the phosphite-based heat stabilizer, and is used in the range of 0.1 to 1.0 parts by weight.

When the thermal stabilizer is used in less than 0.1 part by weight, the effect of improving the thermal stability is insignificant, and when the thermal stabilizer is used in an amount of 2.0 parts by weight or more, the thermal stability is rather deteriorated and the manufacturing cost is increased.

(E) lubricant

In the present invention, the external lubricant and the internal lubricant can be selectively used in addition to the above components. In general, the lubricant is added to improve processability of the resin composition, and serves to smooth and gloss the surface of the final product. The inner lubricant serves to reduce the viscosity of the melt is impregnated inside the polymer, the outer lubricant serves to reduce the extrusion load between the polymer melt in the extruder and the metal surface.

In the present invention, one type of metal stearate is used alone as an external lubricant. The metal stearate includes barium stearate, calcium stearate, magnesium stearate and the like.

Moreover, in this invention, it is preferable to use ethylene bis stearamide and L-C polyethylene wax as internal lubricant.

The amount of the lubricant used in the present invention is preferably 0.2 to 2.0 parts by weight. If the amount of lubricant is less than 0.2 part by weight, it is difficult to expect uniform dispersion in the SAN resin in which the rubber particles in the extrusion process are used as a matrix, and the release property from the mold decreases during injection molding, resulting in release cracking or pin whitening. It lowers the value of the product. On the other hand, if the amount of the lubricant is used in excess of 2.0 parts by weight, it is expected that the uniform dispersion of the rubber particles in the extrusion process and the improvement of flowability, impact resistance, etc., but the heat resistance is lowered.

(F) antistatic agent

Antistatic agents are added to prevent static and dust adhesion in the product assembly process.

In the present invention, N-hydroxy ethyl-n (2-hydroxyalkyl) amine, which is an amine antistatic agent, is used at 0.4-2.0 parts by weight as an antistatic agent. If the amount is less than 0.4 part by weight, the effect of exhibiting antistatic property (large voltage half-life, surface resistance) is insignificant. If it is used in excess of 2.0 parts by weight, the antistatic property no longer improves and the heat resistance of the resin is lowered.

The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

Example

Specifications of (A) ABS resin, (B) SAN resin, (C) silicone graft copolymer, (D) thermal stabilizer, (E) lubricant and (F) antistatic agent used in the following Examples and Comparative Examples Is as follows.

(A) ABS resin

(a ₁ ) Graft emulsion polymerization of a rubbery polymer having a particle diameter of 0.12 μm was used to use an ABS resin having a core-shell form. At this time, the content of PBD was 50% by weight.

(a ₂ ) An ABS resin having a hemi-sphere shape was used by graft emulsion polymerization of a rubbery polymer having a particle diameter of 0.32 μm. At this time, the content of PBD was 58% by weight.

(a ₃ ) The first graft latex was prepared by the presence of a rubbery polymer having a particle size of 0.12 μm and graft-polymerized to an appropriate conversion rate by emulsion polymerization, followed by a particle size of 0.32 in the presence of the prepared primary graft latex. After the addition of a rubbery polymer having a μm, a core-shell type ABS resin prepared in a bi-graft manner to complete the secondary graft reaction was used by continuously adding a residual amount of graft monomer. At this time, the PBD content was 50% by weight.

(B) SAN resin

(b ₁ ) Heat Resistant SAN Resin

28 weight% of acrylonitrile and 72 weight% of (alpha) -methylstyrene were copolymerized, and the weight average molecular weight was 130,000.

(b ₂ ) Low Molecular Weight SAN Resin

35 weight% of acrylonitrile and 65 weight% of styrene monomers were copolymerized, and the weight average molecular weight was 88,000.

(C) Silicone Graft Copolymer

(c ₁ ) graft a vinyl graft copolymer 65-40% by weight of 35-60% by weight of the silicone rubber polymer (c ₂ ) 40-90 parts by weight of the aromatic styrene monomer and 60-10 parts by weight of the acrylonitrile monomer Core-shell copolymer was used.

(D) heat stabilizer

(d ₁ ) 2,6-di-thi-butyl-4-methylphenol was used as the phenolic heat stabilizer.

(d ₂ ) Diphenyl monooctyl phosphite was used as a phosphite thermal stabilizer.

(E) lubricant

As the metal stearate, an external lubricant magnesium stearate was used.

(F) antistatic agent

N-hydroxy ethyl-n (2-hydroxy alkyl) amine, an amine antistatic agent, was used.

Examples 1 to 3

Each component is added to the ABS resin and the SAN resin, which are basic resins, in the amounts shown in Table 1 below, and the cylinder temperature is set at 220-250 ° C., using a twin screw extruder having L / D = 26 and φ = 45MM. After extrusion, the extrudate was prepared in pellet form. The prepared pellets were injection molded to prepare a specimen for evaluation of impact strength and thermal softening temperature, and a specimen for surface gloss and appearance evaluation was prepared separately.

Comparative Example 1

A specimen was prepared in the same manner as in Example 1 except that ABS resin (a ₁ ) obtained by graft polymerization of a rubbery polymer having a particle diameter of 0.12 μm was used for the ABS resin.

Comparative Example 2

A specimen was prepared in the same manner as in Example 1 except that ABS resin (a ₂ ) obtained by graft polymerization of a rubbery polymer having a particle diameter of 0.32 μm was used for the ABS resin.

Comparative Example 3

A specimen was prepared in the same manner as in Example 1, except that ABS resin (a ₃ ) prepared in a bi-graft manner was used for the ABS resin.

Comparative Example 4

A specimen was prepared in the same manner as in Example 1 except that a low molecular weight SAN resin was not used for the SAN resin and only a heat resistant SAN resin was used.

Comparative Example 5

A specimen was prepared in the same manner as in Example 1 except that a heat-resistant SAN resin was not used for the SAN resin and only a low molecular weight SAN resin was used.

Table 1 shows the composition of each component used in Examples 1-3 and Comparative Examples 1-5.

Example Comparative Example One 2 3 One 2 3 4 5 (A) ABS resin (a ₁ ) ABS resin grafted small particle size rubber polymer 20 20 15 30 - - 20 20 (a ₂ ) ABS resin grafted medium particle rubber polymer 10 10 15 - 30 - 10 10 (a ₃ ) ABS resin by bi-graft polymerization - - - - - 30 - - (B) SAN resin (b ₁ ) Heat-resistant SAN resin 30 50 30 30 30 30 70 - (b ₂ ) Low molecular weight SAN resin 40 20 40 40 40 40 - 70 (C) Silicone Graft Copolymer 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 (D) heat stabilizer (D ₁ ) 2,6-di-thi-butyl-4-methylphenol 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 (D ₂ ) diphenyl monooctyl phosphite 0.3 0.3 0.3 0.3 0.3 0.3 0.3 0.3 (E) lubricant 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 (F) N-hydroxyethyl-n (2-hydroxyalkyl) amine 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4

The physical properties of the specimens molded in Examples and Comparative Examples were measured by the following method.

(1) mechanical properties

Izod notch impact strength was measured according to ASTM D256 (1/4 ″, 23 ° C.) and hardness was measured according to ASTM D785 using a Rockwell hardness tester.

(2) thermal properties

Flow index (MI) measured the extrusion amount per 10 minutes at a load of 220 ℃, 10kg in accordance with the standard of ASTM D1238. The thermal softening point temperature was measured at a rate of 50 ° C./hr at a load of 5 kg according to ASTM D1525.

(3) glossiness

The measurement angle was set at 60 ° according to ASTM D2457.

(4) antistatic

Evaluation of antistatic property was carried out at a constant humidity of 50% at 23 ℃ to measure the half-voltage half-life and surface resistance. The large voltage half-life measured the time (sec) for discharging half of the amount of charge accumulated in the material at an applied voltage of 8 kV for 60 seconds immediately after injection. The surface resistance measured the discharge phenomenon of static electricity at an applied voltage of 500V for 30 seconds.

(5) Visual appearance

It was observed whether surface defects such as fish-eye, pin-hole and sand-surface appeared visually.

The physical properties of the resins prepared in Examples 1-3 and Comparative Examples 1-5 are shown in Table 2.

Test Items unit Example Comparative Example One 2 3 One 2 3 4 5 Notched Izod Impact Strength (1/4 ", 23 ℃) kgcm / cm 16 17 15 5 17 12 16 12 Hardness R 110 111 110 111 110 110 110 108 Flow index (10kg, 220 ℃) g / 10min 15 14 14 11 16 12 9 18 Thermal softening point temperature (5kg, 50 ℃ / hr) ℃ 104.8 108.1 104.6 104.1 104.3 104.4 115.1 94.3 Glossiness (60 ° measurement) % 97 97 96 99 91 96 97 97 Visual appearance - ○ ○ ○ ○ × × ○ ○ High voltage half life (8kV, 60 seconds) sec 5 5 5 5 5 5 5 5 Surface resistance (500V, 30 seconds) Ω 10 ³ 10 ³ 10 ³ 10 ³ 10 ³ 10 ³ 10 ³ 10 ³

In the visual appearance, (circle): No surface defects, such as fisheye, were visually observed.

X: The surface defect was visually observed.

As a result of Table 2, in Comparative Example 1 using only the resin (a ₁ ) obtained by graft polymerization of a rubbery polymer having a particle size of 0.12 μm as the ABS resin, it was found that the impact strength and the flow index were decreased. In addition, in Comparative Example 2 using only resin (a ₂ ) obtained by graft polymerization of a rubbery polymer having a particle size of 0.32 μm with an ABS resin, the appearance such as glossiness was poor. In the case of Comparative Example 3 using only the ABS resin (a ₃ ) manufactured by the bi-graft method, the workability and appearance quality were deteriorated.

In Comparative Example 4 using only heat-resistant SAN resin as the SAN resin, the thermal characteristics were excellent, but the flow index was very low. In addition, in Comparative Example 5 using only a low molecular weight SAN resin as the SAN resin, the flow index was excellent, but the softening point temperature was found to be very low.

According to the present invention, two kinds of rubber polymers having different rubber particle sizes are graft polymerized to prepare ABS resin separately, and the mixture is used in the compounding process. It has the effect of providing a heat resistant thermoplastic resin composition having both physical property balance and excellent fluidity and antistatic properties.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (3)

(A) (a ₁₎ an average particle size by using 0.08-0.18㎛ rubber using a graft polymer, and (a ₂₎ of rubber has an average particle size 0.28-0.38㎛ prepared by graft polymerization grafting 20-60% by weight of the ABS resin composed of 40:60 to 80: 20% by weight of the graft polymer prepared by the wort polymerization method; And (B) 30-90% by weight of AMS-based heat-resistant SAN resin consisting of 65-78% by weight of (b ₁ ) α-methylstyrene and 35-22% by weight of acrylonitrile and (b ₂ ) 65-78% by weight of styrene and acrylic 80-40% by weight of a SAN resin composed of 70-10 parts by weight of a low molecular weight SAN resin having a molecular weight of 80,000-120,000 consisting of 35-22% by weight of ronitrile; A heat resistant thermoplastic resin composition, characterized in that consisting of. According to claim 1, Optionally, based on 100 parts by weight of the resin composition (C) 0.1-2.0 parts by weight of the silicone graft copolymer; (D) 0.1-2.0 parts by weight of heat stabilizer; (E) 0.2-2.0 parts by weight of lubricant; And / or (F) 0.4-2.0 parts by weight of antistatic agent; Heat-resistant thermoplastic resin composition comprising a further. According to claim 2, wherein the (C) silicone graft copolymer is (c ₁ ) 35-60% by weight of the silicone rubber polymer and (c ₂ ) aromatic styrene monomer, the average particle size of the rubber particles in the range of 200-400㎛ A heat-resistant thermoplastic resin composition consisting of 65-40% by weight of a vinyl-based graft copolymer composed of 40-90% by weight and 60-10% by weight of acrylonitrile monomers.