JPH11349641A - Rubber-modified styrene resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a rubber-modified styrene resin composition which has well balanced mechanical properties such as flow properties, a heat resistance, a rigidity and a stretch and can be molded with a drastically shortened molding time. SOLUTION: A rubber-modified styrene resin composition comprises a continuous phase of a styrene polymer obtained by polymerizing styrene nomomers in the presence of a rubbery polymer wherein the 5 wt.% styrene solution viscosity, determined at 25 deg.C, is from 100 to 400 centipoise and a dispersed phase of soft component particles comprising a rubbery polymer including styrene polymers. Here, the weight average molecular weight of the styrene polymer forming the continuous phase is from 140,000 to 180,000, the content of the rubbery polymer forming the dispersed phase is from 4.0 to 9.0 wt.% and the content of a mineral oil in the resin composition is from 0.1 to 1.1 wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to fluidity, heat resistance,
The present invention relates to a rubber-modified styrenic resin composition that has an excellent balance of physical properties such as rigidity and elongation and that can significantly reduce molding time.

[0002]

2. Description of the Related Art Rubber-modified styrenic resin compositions are excellent in rigidity, moldability, dimensional stability and impact resistance. It is widely used as a material for goods. In recent years, with the development of molding technology, the shape of molded products tends to be complicated, large, and thin, and furthermore, because of the improvement in productivity by shortening the molding cycle, it has an excellent balance of fluidity, heat resistance, and rigidity. There is a strong demand for the development of rubber-modified styrenic resins. As a method of improving fluidity, for example, a method of adding a plasticizer such as mineral oil is generally performed as proposed in Japanese Patent Application Laid-Open No. 60-192755. By the addition of the plasticizer, the fluidity is improved and the molding temperature can be lowered. However, since the heat resistance is reduced, there is a problem that the solidification temperature of the molded article is lowered, the solidification time is relatively long, and the productivity is conversely reduced. Also, Japanese Patent Laid-Open No. 24744/1990
No. 6, JP-A No. 9-111071 discloses a resin having an excellent balance between fluidity and heat resistance by limiting the content of a rubbery polymer, the molecular weight of a styrene resin in a continuous phase, the content of a plasticizer, and the like. Proposed. In these methods, the balance between fluidity and heat resistance is slightly improved, but the heat resistance is insufficient for shortening the solidification time, the tensile yield stress is low and the rigidity of the molded product is insufficient, There was a drawback that molding was difficult. In addition, Japanese Patent Application Laid-Open No. 5-33942
No. 0 and JP-A-6-157920 disclose a third component such as a hydroxy group-containing aromatic phosphate ester, a compound having a specific functional group, an organic compound having a plasticizing effect, and a fat and oil gelling agent. Thus, a technique for improving the balance between heat resistance and fluidity has been proposed. However, these methods do not have a sufficient fluidity improving effect, and the additives used are relatively expensive, which increases the production cost of the resin and is not preferable from an industrial viewpoint.

[0003]

The problem to be solved by the present invention is to provide a rubber-modified styrene-based material which has an excellent balance of fluidity, heat resistance, rigidity and elongation, and is capable of greatly shortening the molding time. It is to provide a resin composition.

[0004]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have determined the styrene solution viscosity of the rubbery polymer to be used, and formed a styrene-based polymer forming a continuous phase. Controlling the weight average molecular weight of the specific range, the amount of the rubbery polymer of the soft component forming a dispersed phase,
Furthermore, it has been found that the above problem can be solved by using a rubber-modified styrene-based resin composition in which the content of mineral oil in the resin composition is controlled within a specific range, and the present invention has been completed.

That is, the present invention provides a soft component particle comprising a continuous phase of a styrenic polymer and a rubbery polymer containing a styrenic polymer, which is obtained by polymerizing a styrenic monomer in the presence of a rubbery polymer. In a rubber-modified styrenic resin composition having a dispersion phase of: 1) the viscosity of a 5% by weight styrene solution measured at a temperature of 25 ° C. of a rubbery polymer to be used is 100 to 400 centipoise; When the content of the rubbery polymer is 4.0 to 4.0
3) the weight average molecular weight of the styrenic polymer forming the continuous phase is 140,000 to 180,000; and 4) the content of mineral oil in the resin composition is 0.1.
To 1.1% by weight of a rubber-modified styrene resin composition.

Hereinafter, the present invention will be described in detail. In the rubber-modified styrenic resin composition of the present invention, the rubbery polymer used is generally a polybutadiene, styrene-butadiene random or block copolymer, but polyisoprene, styrene-isoprene random or block copolymer. Coalesce, ethylene-propylene rubber,
Ethylene-propylene-diene rubber, acrylic rubber and the like can be used alone or in combination of two or more.

Further, the rubbery polymer used has a temperature of 25 ° C.
5% by weight styrene solution viscosity measured at 100 to 400
Centipoise, preferably 150 to less than 300 centipoise. When the solution viscosity is less than 100 centipoise, the effect of improving the elongation by adding mineral oil to the resin composition is small, and even if the mineral oil content is increased to the upper limit shown in the present invention, the elongation is increased to a level that satisfies the elongation. I can't do that. In order to improve elongation, the mineral oil content will be further increased, and as a result, heat resistance and tensile yield stress will decrease, and the fluidity, heat resistance, rigidity and elongation of the present invention will be excellent in the balance of physical properties. A modified rubber-modified styrenic resin composition cannot be obtained. On the other hand, if the solution viscosity is so high as to exceed 400 centipoise, a long time is required for the rubber dissolving step, which is not preferable in production.

In the rubber-modified styrenic resin composition of the present invention, the content of the rubbery polymer is from 4.0 to 9.0.
0% by weight, and preferably 5.0 to 8.0% by weight. When the content of the rubbery polymer exceeds 9.0% by weight,
The tensile yield stress decreases. On the other hand, if it is less than 4.0% by weight, impact resistance and elongation decrease.

[0009] The content of the rubbery polymer in the rubber-modified styrene resin composition was measured as follows. Dissolve the rubber-modified styrenic resin composition in chloroform,
A fixed amount of an iodine monochloride / carbon tetrachloride solution was added, and the mixture was allowed to stand in a dark place. After about 1 hour, add potassium iodide solution,
Excess iodine monochloride was titrated with 0.1N sodium thiosulfate / ethanol aqueous solution, and the content of the rubbery polymer was calculated from the amount of iodine monochloride added.

In the rubber-modified styrenic resin composition of the present invention, the rubbery polymer must include the styrene-based polymer and be dispersed in the styrene-based polymer in a continuous phase. The dispersed particles preferably have a so-called salami structure. Although the particle diameter of the soft component particles of the rubbery polymer containing the styrene-based polymer constituting the dispersed phase is not particularly limited, the volume average particle diameter is 1.5 to 4.0 μm.
m is preferred.

Here, the volume average particle diameter of the soft component particles was evaluated as follows. That is, the rubber-modified styrenic resin composition was completely dissolved in dimethylformamide, and the obtained sample was determined by the following particle size distribution analyzer. Measuring device: Coulter Laser Diffraction Particle Analyzer LS-230 Model Solvent: Dimethylformamide

The styrene polymer constituting the continuous phase of the rubber-modified styrene resin composition of the present invention is a polymer of a styrene monomer. As the styrene-based monomer, styrene is generally used, and nuclei such as o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, ethylstyrene, and p-tert-butylstyrene are used. Alkyl-substituted styrene, α-methylstyrene, α-
Α-alkyl-substituted styrenes such as methyl-p-methylstyrene and the like can be used alone or in combination of two or more.

Further, a vinyl monomer copolymerizable with a styrene monomer can be copolymerized. Examples of the copolymerizable vinyl monomer include acrylic acid, methyl methacrylate, and acrylonitrile. These vinyl monomers can be used alone or in combination of two or more.

The styrene polymer constituting the continuous phase of the rubber-modified styrenic resin composition of the present invention has a weight average molecular weight of 14
10,000 to 180,000. When the weight average molecular weight is less than 140,000, the fluidity increases and the molding temperature can be lowered, but it is not preferable because elongation and tensile yield stress decrease. For example, when the elongation and the tensile yield stress are reduced, when a thin molded body is fitted without using a screw or the like, a problem occurs that the fitted portion comes off with a small impact.
On the other hand, when the weight average molecular weight exceeds 180,000, the fluidity decreases, and it is necessary to increase the molding temperature, and high-speed molding becomes difficult.

Here, the weight average molecular weight of the styrene polymer constituting the continuous phase was evaluated as follows. That is, the rubber-modified styrenic resin composition was converted to methyl ethyl ketone (ME
K), and after separating insoluble components by centrifugation, the supernatant was precipitated using methanol. 35 mg of the obtained sample was placed in a tetrahydrofuran (THF) 30 m
and filtered, then gel permeation.
The measurement was performed using a chromatograph (GPC) under the following conditions. Measuring device: SHOdex SYSTEM- manufactured by Showa Denko
21 Column: POLYMER LABORATORY I
NC. PL gelMIXED-B x 3 Solvent: tetrahydrofuran Quantitation: calibration curve using standard polystyrene

Further, in the rubber-modified styrenic resin composition of the present invention, the mineral oil content is 0.1 to 1.
It needs to be 1% by weight. When the mineral oil content is less than 0.1% by weight, the elongation is significantly reduced. On the other hand, when the mineral oil content exceeds 1.1% by weight, the heat resistance decreases and the tensile yield stress decreases. The mineral oil may be added at the time of polymerization or at the time of extrusion granulation, and the addition method is not particular.

The mineral oil is not particularly limited, but preferably has a 2.5% by weight distillation point at a temperature of 240 ° C. or higher under a reduced pressure of 10 mmHg measured by ASTM-D1160.

The content of mineral oil in the rubber-modified styrenic resin composition of the present invention is determined by dissolving the obtained resin composition in petroleum ether, extracting a sample containing mineral oil, and obtaining a sample. The mineral oil content in the sample was measured by gas chromatography under the following conditions. Measuring device: Hewlett Packard HP5890-I
I column: Capillary column HP-5 (0.2 mm
Φ × 12m) Temperature: 50-300 ° C

Next, a method for producing the rubber-modified styrenic resin composition of the present invention will be described. The production of the rubber-modified styrenic resin composition of the present invention is not particularly limited as long as the requirements of the present invention are satisfied, but may be obtained by a known continuous bulk polymerization method or a bulk-suspension polymerization method or the like. Can be.

Hereinafter, a method of performing the continuous bulk polymerization method and the bulk-suspension polymerization method will be described. In the continuous bulk polymerization method, a rubber-like polymer is dissolved in a styrene-based monomer, and a solvent is added as necessary.
Heat polymerization is carried out at 200 ° C. and at a temperature of 60 to 180 ° C. in the case of catalytic polymerization. After completion of the polymerization, unreacted styrene-based monomers and solvents are removed by heating under reduced pressure to obtain pellets.

In the bulk-suspension polymerization method, the first half of the reaction is carried out by bulk polymerization, and the second half of the reaction is carried out by suspension polymerization. The styrene-based monomer is partially polymerized by thermal polymerization or catalytic polymerization, usually up to 50% by weight of the styrene-based monomer. The partially polymerized mixture is then dispersed in an aqueous medium under agitation in the presence of a suspension stabilizer or both of this and a surfactant to complete the polymerization reaction. After the completion of the polymerization, the polymer is washed and dried, and if necessary, formed into a normal pellet shape by an extruder.

In any method, the rubber-modified styrene type satisfying the conditions of the present invention is adjusted by adjusting the concentration of the rubbery polymer, the stirring power, the polymerization temperature, the amount of the plasticizer, the amount of the chain transfer agent and the like during the polymerization reaction. A resin composition can be obtained.

The resin of the present invention may contain, if necessary, a lubricant, a release agent, a heat stabilizer, an antioxidant, an antistatic agent, a strength reinforcing agent,
Additives such as flame retardants can be added.

[0024]

EXAMPLES Examples are shown below, but the present invention is not limited to these examples. The data shown in the examples was measured based on the following method. (1) Melt flow rate Based on JIS K 7210, 5 g of a sample is put into a cylinder, a weight is placed after the piston is inserted, the resin extruded within a certain time after preheating for 6 minutes is cut out, weighed after cooling, and calculated. did. Measuring device: Toyo Seiki Melt Indexer Temperature: 200 ° C Load: 5 kg (2) Vicat softening point Based on JIS K7206, a test piece is placed on the device frame, a specified 5 kg load is applied, the heat transfer medium is heated, and the indenter is heated. The temperature when the tip penetrated 1 mm into the test piece was read. Measuring device: Toyo Seiki fully automatic Vicat softening point measuring device Heating rate: 50 ° C./hour Load: 5 kg Test piece: 30.0 mm × 19.0 mm × 3.2 mm Indenter: Cross-sectional area 1 mm ² (3) Tensile yield stress, According to ASTM D638, the test piece was attached to the grip of the apparatus, the apparatus was started, and the measurement was continued until the test piece broke. The tensile yield stress and elongation were read from the load-elongation curve. The tensile yield stress was used as a measure of rigidity. Measuring device: Orientec fully automatic tensile tester RTM
-500 Tensile speed: 5 mm / min Specimen: Type I dumbbell Chuck spacing: 114 mm (4) Izod impact strength Based on ASTM D256, a V-notch is inserted into the specimen, the lower part of the notch is fixed, and the specimen is beaten with a hammer. The impact strength was determined from the energy required to break the sample. Measuring device: Toyo Seiki fully automatic impact tester Test piece: 63.5 mm x 12.7 mm x 6.4 mm V notch: 2.54 mm deep at a position 31.8 mm from one end of the test piece, opening angle 45 degrees, Tip 0.25R (5) Molding time Under the following conditions, the molding temperature was adjusted to three levels (200, 220, 2
40 ° C.), the spiral flow was measured, and the relationship between the temperature and the flow length was plotted.
The temperature (T) that resulted in m was read. Injection molding machine: Toshiba Machine's IS-30 EPN mold
: Mold for spiral flow measurement (Archimedes type) Mold temperature: 40 ° C Injection pressure: 50 kg / cm ² G Next, a test piece is molded at a temperature (T) at which the flow length becomes the same 35 cm, and the test piece is formed. The solidification time was defined as the shortest cooling time during which no warpage occurred, and the evaluation was made according to the following criteria. Test piece: 127.0 mm x 12.7 mm x 6.4 m
m Judgment criteria: (○): solidification time of less than 8 seconds (△): solidification time of 8 seconds or more and less than 10 seconds (×): solidification time of 10 seconds or more The shorter the solidification time, the shorter the molding time.

Example 1 To 89.0 parts by weight of a styrene monomer, 0.5 parts by weight of a mineral oil and 5.0 parts by weight of ethylbenzene as a solvent were added, and polybutadiene rubber (trade name: Diene 55A, manufactured by Asahi Kasei Corporation) was added. 5.5 parts by weight were dissolved to obtain a raw material liquid. This raw material liquid is continuously supplied at a rate of 15 L / hour to a complete mixing tank type reactor (hereinafter referred to as CSTR) having an internal volume of 40 L, and at the same time, a polymerization initiator 1,1-bis (tert-butylperoxy) A solution obtained by diluting -3,3,5-trimethylcyclohexane to 3% by weight with ethylbenzene was continuously supplied into the CSTR at a rate of 50 g / h.
Further, the temperature of the polymerization liquid in the CSTR was controlled at 128 ° C., and the polymerization liquid was continuously taken out such that the amount of the polymerization liquid retained in the CSTR was 20 L. A part of the polymerization solution taken out from the CSTR was dissolved in methyl ethyl ketone and precipitated with a large amount of methanol, and the total solid content was measured to be about 30% by weight. Then, CS
The polymerization liquid taken out from the TR is continuously supplied to a column-type reactor (hereinafter, referred to as PFR) having an internal volume of 40 L, and at the same time,
A solution obtained by diluting tertiary decyl mercaptan to 20% by weight with ethylbenzene is subjected to PFR at a rate of 40 g / h.
Continuously. Further, the temperature of the polymerization liquid in the PFR was continuously increased from 130 ° C. to 170 ° C., and the polymerization liquid was continuously taken out. Next, the polymerization liquid taken out of the PFR was supplied to a devolatilizer to separate volatile components such as unreacted monomers and solvents. From the generation rate of volatile components, P
When the solid content at the FR outlet was calculated, it was approximately 80
% By weight. Next, the polymerization liquid taken out of the devolatilization device was supplied to a granulation device, and was made into a usual pellet shape.
Table 1 shows the physical properties of the obtained resin composition.

Example 2 0.5 parts by weight of mineral oil, 5.0 parts by weight of ethylbenzene, and 4.5 parts by weight of polybutadiene rubber were dissolved in 90.0 parts by weight of a styrene monomer to prepare a raw material liquid. Except for this, the procedure was the same as in Example 1. Table 1 shows the physical properties.

Example 3 Without using a polymerization initiator, the temperature of the polymerization solution in the CSTR was adjusted to 1
At 38 ° C., a solution prepared by diluting tertiary decyl mercaptan to 10% by weight with ethylbenzene was added at a rate of 40 hours / hour.
The procedure was performed in the same manner as in Example 1 except that the PFR was continuously supplied at a speed of g. Table 1 shows the physical properties.

Example 4 Without using a polymerization initiator, the temperature of the polymerization solution in the CSTR was adjusted to 1
At 38 ° C., a solution prepared by diluting tertiary decyl mercaptan to 10% by weight with ethylbenzene was added at a rate of 40 hours / hour.
The procedure was performed in the same manner as in Example 2, except that the PFR was continuously supplied at a rate of g. Table 1 shows the physical properties.

Example 5 A styrene monomer 3 was placed in a 60-liter autoclave.
7.80 kg and 0.20 kg of mineral oil were added, and polybutadiene rubber (trade name BR-2 manufactured by Ube Industries, Ltd.) was added.
2H) 2.00 kg was dissolved to obtain a raw material liquid. 16 g of tert-butyl peroxy-3,5,5-trimethylhexanoate, 5 g of ethyl-3,3-di (tert-butyl peroxy) butyrate, 40 g of tert-butyl decyl mercaptan, α-methylstyrene 50 g of dimer was added and stirred. After the inside of the autoclave was purged with nitrogen, the temperature was increased and the temperature was increased.
After polymerization for an hour, the mixture was cooled to complete the preliminary polymerization. Next, 50 kg of pure water, 0.50 g of sodium dodecylbenzenesulfonate and 500 g of tribasic calcium phosphate were added and stirred in a 150 L autoclave, and the above prepolymerized solution and 2,2-di (tert-butylperoxy) were added. After 75 g of butane and 40 g of ethyl-3,3-di (tert-butylperoxy) butyrate were added, the mixture was replaced with nitrogen, sealed, heated, and polymerized at 110 ° C. for 4 hours and 132 ° C. for 4 hours and cooled. After neutralization, dehydration and drying according to the usual method,
A polymer was obtained. 100 parts by weight of this polymer were zinc stearate as a lubricant and Irga as an antioxidant.
Nox 1076 was added in an amount of 0.05 part by weight, and formed into a normal pellet shape by an extruder. Table 2 shows the physical properties of the obtained resin composition.

Example 6 The styrene monomer content in the raw material liquid was 37.96 kg, the mineral oil content was 0.04 kg, and the amount of α-methylstyrene dimer added during the prepolymerization was 90 g.
Was performed in the same manner as in Example 5, except that Table 2 shows the physical properties.

Example 7 The raw material liquid had a styrene monomer content of 37.20 kg, a mineral oil content of 0.40 kg, and a polybutadiene rubber content of 2.40 kg.
The same procedure as in Example 5 was carried out except that the amount of the methylstyrene dimer added was 40 g. Table 2 shows the physical properties.

Example 8 A 1,4-cis content of 97.6% by weight, a 1,2-vinyl content of 1.2% by weight, and a Mooney viscosity (ML _{1 + 4} )
Was carried out in the same manner as in Example 7, except that a polybutadiene rubber having a viscosity of 5 and a 5% by weight styrene solution measured at a temperature of 25 ° C. of 165 was used. Table 2 shows the physical properties.

Comparative Example 1 A raw material solution obtained by dissolving 0.5 parts by weight of mineral oil, 5.0 parts by weight of ethylbenzene, and 6.0 parts by weight of polybutadiene rubber was dissolved in 88.5 parts by weight of a styrene monomer. The procedure was carried out in the same manner as in Example 1 except that a solution prepared by diluting tert-idodecyl mercaptan to 20% by weight with ethylbenzene was continuously supplied to the PFR at a rate of 50 g / h. Table 3 shows the physical properties of the obtained resin composition.

Comparative Example 2 A raw material liquid obtained by dissolving 0.5 parts by weight of mineral oil, 5.0 parts by weight of ethylbenzene, and 7.2 parts by weight of polybutadiene rubber was dissolved in 87.3 parts by weight of a styrene monomer. And a solution obtained by diluting tertiary decyl mercaptan to 5% by weight with ethylbenzene is added to P at a rate of 50 g / h.
The same procedure as in Example 1 was performed except that the FR was continuously supplied. Table 3 shows the physical properties.

Comparative Example 3 A raw material liquid obtained by dissolving 0.5 parts by weight of mineral oil, 5.0 parts by weight of ethylbenzene, and 2.8 parts by weight of polybutadiene rubber was mixed with 91.7 parts by weight of a styrene monomer. The procedure was performed in the same manner as in Example 1 except that a solution obtained by diluting tertiary decyl mercaptan to 10% by weight with ethylbenzene was continuously supplied to the PFR at a rate of 50 g / h. Table 3 shows the physical properties.

Comparative Example 4 A raw material liquid obtained by dissolving 0.5 parts by weight of mineral oil, 5.0 parts by weight of ethylbenzene, and 8.0 parts by weight of polybutadiene rubber was mixed with 86.5 parts by weight of a styrene monomer. The procedure was performed in the same manner as in Example 1 except that a solution obtained by diluting tertiary decyl mercaptan to 10% by weight with ethylbenzene was continuously supplied to the PFR at a rate of 50 g / h. Table 3 shows the physical properties.

Comparative Example 5 A raw material liquid was prepared by dissolving 5.0 parts by weight of ethylbenzene and 6.0 parts by weight of polybutadiene rubber without adding mineral oil to 89.0 parts by weight of a styrene monomer. Except for this, the procedure was the same as in Example 1. Table 3 shows the physical properties.

Comparative Example 6 A raw material solution obtained by dissolving 2.0 parts by weight of mineral oil, 5.0 parts by weight of ethylbenzene, and 5.5 parts by weight of polybutadiene rubber with respect to 87.5 parts by weight of a styrene monomer was used. The procedure was performed in the same manner as in Example 1, except that Table 4 shows the physical properties.

Comparative Example 7 The type of polybutadiene rubber used was Asahi Kasei's diene 35A (trade name), and 0.5 parts by weight of mineral oil and 5.0 parts by weight of ethylbenzene were used for 88.5 parts by weight of a styrene monomer. Parts, a solution prepared by dissolving 6.0 parts by weight of polybutadiene rubber was used as a raw material liquid, and a solution prepared by diluting tertiary decyl mercaptan to 10% by weight with ethylbenzene was continuously supplied to the PFR at a rate of 50 g / h. The same procedure as in Example 1 was performed. Table 4 shows the physical properties of the obtained resin composition.

Comparative Example 8 The type of polybutadiene rubber used was BR-15H (trade name, manufactured by Ube Industries, Ltd.), the styrene monomer content in the raw material liquid was 37.40 kg, and the mineral oil content was 0.20 k.
g, except that the polybutadiene rubber content was 2.40 kg. Table 4 shows the physical properties of the obtained resin composition.

Comparative Example 9 The type of polybutadiene rubber to be used was BR-15H (trade name, manufactured by Ube Industries, Ltd.), the styrene monomer content in the raw material liquid was 36.28 kg, and the mineral oil content was 0.52 k.
g, polybutadiene rubber content is 3.20 kg,
The procedure was performed in the same manner as in Example 5, except that the amount of the α-methylstyrene dimer added during the prepolymerization was 90 g. Table 4 shows the physical properties.

Comparative Example 10 The kind of polybutadiene rubber used was Asaprene 1005A (trade name, manufactured by Asahi Kasei Corporation), the styrene monomer content in the raw material liquid was 37.40 kg, and the mineral oil content was 0.
Example 5 was repeated except that the content of polybutadiene rubber was 20 kg, the content of polybutadiene rubber was 2.40 kg, and the amount of α-methylstyrene dimer added during prepolymerization was 90 g. Table 4 shows the physical properties.

[0043]

[Table 1]

[0044]

[Table 2]

[0045]

[Table 3]

[0046]

[Table 4]

As compared with the examples and the comparative examples, the viscosity of the styrene solution at a specific temperature of the rubbery polymer used satisfies a value in a specific range, and the weight-average molecular weight of the styrene-based polymer forming the continuous phase. Is controlled to a specific range, that the content of the rubbery polymer of the soft component constituting the dispersed phase is in the specific range, and that the resin composition satisfying that the mineral oil content is also in the specific range. It can be seen that only the fluidity, heat resistance, rigidity, and the balance of physical properties of elongation are excellent, and the molding time can be significantly reduced.

[0048]

The rubber-modified styrenic resin composition of the present invention not only has excellent physical properties such as fluidity, heat resistance, rigidity and elongation, but also can greatly reduce the molding time. It can be widely used in industrial fields such as home appliances, OA equipment, and miscellaneous goods.

Claims (3)

[Claims] A styrene-based monomer is polymerized in the presence of a rubber-like polymer, and a continuous phase of a styrene-based polymer and soft component particles of a rubber-like polymer containing a styrene-based polymer are dispersed in a dispersed phase. 1) The 5% by weight styrene solution viscosity of the rubbery polymer to be used measured at 25 ° C. is 100 to 400 centipoise, and 2) the rubbery weight in the resin composition. When the content of the coalescence is 4.0
3) the weight average molecular weight of the styrenic polymer forming the continuous phase is 140,000 to 180,000; and 4) the content of mineral oil in the resin composition is 0.1.
A rubber-modified styrenic resin composition, characterized in that the composition is 0.1 to 1.1% by weight. 2. The melt flow rate is 6.5 to 12.0.
The rubber-modified styrenic resin composition according to claim 1, wherein the composition is g / 10 minutes. 3. The rubber-modified styrene system according to claim 1, wherein the Vicat softening point is 95 ° C. or more, the tensile yield stress is 290 kg / cm ² or more, and the elongation is 20% or more. Resin composition.