JPH0987444A - Rubber-modified styrene-based resin composition and molded product therefrom - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition excellent in impact strength, oil resistance and molding processabilty, also excellent in performances such as other physical properties required for sheathing materials, packaging materials and expanded forms, and to obtain a molded product from the resin composition. SOLUTION: This resin composition comprises (A) 100 pts.wt. of a rubber- modified styrene-based resin containing 5-35wt.% of flexible component particles which have an average diameter of >2.5 to 5μm and a swelling degree of 3-30 and (B) 0.1-250 pts.wt. of an aromatic vinyl compound unit-free polymer 8.45-8.70 in solubility parameter(SP). The objective molded products such as injection molded products, extrusion molded products and expanded molded products are obtained by using this resin composition.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rubber-modified styrenic resin composition excellent in impact strength and oil resistance, and more specifically, it has improved impact strength and oil resistance and, at the same time, has other physical properties. The present invention relates to a rubber-modified styrene-based resin composition whose molding processability is not deteriorated.

[0002]

2. Description of the Related Art In the field of applications such as office automation equipment and home electric appliances, it is required that workability at the time of molding, finished dimensional accuracy of processed products, mechanical properties such as tension and bending, and various physical properties such as heat resistance are well balanced. Although it is required, improvement in impact strength is further required especially in terms of moldability and exterior materials. Such demands have become increasingly high in recent years. As a method of improving impact strength, a method of adding a soft component such as a styrene-butadiene block copolymer to a rubber-modified styrene resin is well known. However, since the butadiene portion of these soft components has low heat resistance, if they stay at a high temperature (about 180 ° C to 250 ° C) during molding, a gel component will be generated and they will remain in the molded product as bumps and leave a rough surface. However, there is a problem that the appearance is deteriorated. Further, in order to prevent these gel components from entering the molded product, it is necessary to purge a large amount of resin, which requires a long time and a large amount of resin. Also, when used as a packaging material, a high level of impact strength is required.
Particularly when used for food applications, oil resistance may be required. When it is used as a cushioning material, one of the essential characteristics that it should have is that it has excellent shock absorption. However, the rubber-modified styrene resin composition is
From the viewpoint of sufficiently satisfying all the above requirements, it is difficult to say that the requirements are sufficient.

[0003]

SUMMARY OF THE INVENTION The object of the present invention is to solve the above problems and to provide excellent impact strength, oil resistance and molding processability, and excellent performance required for exterior materials, packaging materials, and foamed molded articles. Another object of the present invention is to provide a rubber-modified styrene resin composition and a molded product thereof.

[0004]

The present inventors have arrived at the present invention as a result of intensive studies to solve the above problems. That is, one of the inventions is 100 parts by weight of the following component (A) and 0.1 to 250 component (B).
The present invention relates to a rubber-modified styrene resin composition containing parts by weight. (A): A rubber-modified rubber containing 5 to 35% by weight of soft component particles, having an average particle diameter of the soft component particles of more than 2.5 μm and 5 μm or less and a swelling degree of the soft component particles of 3 to 30. Styrenic resin (B): solubility parameter (SP) is 8.45 to 8.7.
0, and the polymer does not contain an aromatic vinyl compound unit in the polymer. Further, in the present invention, another invention is an injection-molded article, an extrusion-molded article, a foamed article using the above rubber-modified styrene-based resin composition. It relates to molded articles.

The details will be described below.

BEST MODE FOR CARRYING OUT THE INVENTION The rubber-modified styrenic resin (A) used in the present invention is one or more styrenic monomers, or one or two or more styrenic resins in the presence of a rubbery polymer. A rubber-modified styrene resin obtained by polymerizing a monomer and a compound copolymerizable therewith.

Examples of the styrene-based monomer used as a raw material for the rubber-modified styrene-based resin (A) used in the present invention include, for example, styrene and α-methylstyrene and other α-
Examples thereof include alkyl-substituted styrene and nuclear-substituted alkylstyrene such as p-methylstyrene. Examples of the compound copolymerizable with the styrene-based monomer include vinyl monomers such as acrylonitrile, methacrylonitrile, methacrylic acid and methyl methacrylate, and maleic anhydride, maleimide, and nucleus-substituted maleimide. Examples of the rubber-like polymer include polybutadiene, styrene-butadiene copolymers, ethylene-
Propylene-non-conjugated diene terpolymers and the like are used, among which polybutadiene and styrene-butadiene copolymers are most preferred. As the polybutadiene, both high cis polybutadiene having a high cis content and low cis polybutadiene having a low cis content can be used.

The content of the soft component particles in the rubber-modified styrene resin (A) used in the present invention is 5 to 35% by weight. If the content of the soft component particles is less than 5% by weight, the composition containing the resin is inferior in impact strength, and if it is more than 35% by weight, the rigidity is inferior. In the present invention, the content of the soft component particles in the rubber-modified styrene resin (A) is measured by the following method. That is, about 0.5 g of a rubber-modified styrene resin as a sample is weighed (weight: W ₁ ) and collected,
The sample is dissolved in 50 ml of methyl ethyl ketone / methanol mixed solvent (volume ratio 10/1) at room temperature (about 23 ° C.). Next, the insoluble matter at the time of dissolution is isolated by centrifugation, the insoluble matter is dried, and its weight (W ₂ ) is measured. The content of the soft component particles in the rubber-modified styrene resin is calculated by (W ₂ / W ₁ ) × 100 (%). The average particle size of the soft component particles is more than 2.5 μm and 5 μm or less, preferably 2.6 μm to 4 μm.
If the average particle size of the soft component particles is 2.5 μm or less, the composition containing the resin is inferior in impact strength and oil resistance and is 5 μm.
If it is larger, the rigidity and appearance are poor. The average particle size is defined as follows. An ultrathin section of rubber-modified styrene resin was prepared, a transmission electron microscope photograph was taken, and the soft component particle diameter in the photograph was measured.

[0008]

## EQU00001 ## Average particle size = .SIGMA. (Ni.Di) /. SIGMA.ni where ni is the number of particles having a particle size Di.

In the present invention, the soft component particles in the (A) rubber-modified styrenic resin include, for example, a core portion which is a single continuous phase consisting of only the styrene resin and an occlude occlude of the core portion. Those having a single occlusion structure (also referred to as core / shell structure or capsule structure) composed of a shell portion made of a rubber-like polymer, or a small number of styrene-based resins in a continuous phase made of a rubber-like polymer. Examples thereof include particles having a so-called salami structure in which particles are dispersed, but the structure is not particularly limited. The structure of the soft component particles is observed by using a transmission electron microscope as in the above-mentioned measurement of the average particle size. The swelling degree of the soft component particles in the (A) rubber-modified styrene resin of the present invention is 3 to 30, preferably 8 to 20. Swelling degree is 3
When it is smaller, the composition containing the resin is inferior in impact strength, and when it is larger than 30, the composition is inferior in rigidity and appearance, which is not preferable in practical use. The degree of swelling of the soft component particles of the rubber-modified styrene resin (A) of the present invention is determined by the following method. That is, about 1.0 g of a rubber-modified styrenic resin, which is a sample, is dissolved in 50 ml of toluene at room temperature and left for one day. The obtained toluene solution was centrifuged (100
(00 rpm × 30 minutes) to separate insoluble matter. The supernatant liquid is discarded, the insoluble matter is weighed, and the weight is defined as a.
Next, the insoluble matter is dried with a vacuum dryer (70 ° C. × 3 hours), and the weight after drying is set to b. Swelling degree is (ab)
/ B. As the method for producing the rubber-modified styrene resin (A) used in the present invention, a bulk polymerization method or a bulk / suspension two-stage polymerization method is used. Then, the rubber-like polymer concentration during the polymerization reaction, the stirring speed, by adjusting the temperature, etc., required in the present invention, the content of the soft component particles, the average particle diameter of the particles, conditions such as swelling degree It is possible to obtain a rubber-modified styrenic resin satisfying

Next, in the present invention, a polymer (B) having a solubility parameter (SP) of 8.45 to 8.70 and containing no aromatic vinyl compound unit is added to the composition (A) rubber-modified styrene type. 0.1-2 for 100 parts by weight of resin
The content is 50 parts by weight, but if the content is less than 0.1 parts by weight, impact strength and oil resistance are not sufficient, and if it exceeds 250 parts by weight, other physical properties such as rigidity are deteriorated, which is not preferable. The content of the component (B) in the composition of the present invention is converted from the area ratio of the component (B) occupying in the photograph by making an ultrathin section of the composition and taking a transmission electron micrograph of the composition. You can ask. In addition, a method of obtaining from the absorption peak using a spectroscope such as NMR or IR, a method of performing fractionation using a solvent, and the like can be used. Further, (B) of the present invention
The solubility parameter (SP) of the component is 8.45-8.70.
If it is smaller than 8.45 or larger than 8.70, the effect of improving the impact strength is not sufficient. The solubility parameter here means Hildebrand-Satchch.
It defines the attractive force between molecules according to Ard's theory. For detailed explanations, general textbooks on polymer science,
For example, "Polymer Blend, Saburo Akimoto, et al., CMC, 4th edition, pages 125-144 (1991)".
Etc. However, there are a method for obtaining this solubility parameter by experiments such as a viscosity method and a swelling degree method and a method for obtaining it by calculation from a molecular structure, and the value is slightly different depending on the method. Therefore, the method of calculating from the molecular structure proposed by Small was used here. This method and theory is described in "Journal of Applied Chemistry.
Chemistry, Volume 3, pp. 71-80 (1953)
Year) ”. Therefore, the solubility parameter was calculated using the following formula.

[0011]

[Equation 2] Fi is a molar attraction force of a constituent group such as an atom or an atomic group constituting a molecule, a bond type, V is a molar volume, ρ is a density, and M is a molecular weight. Indicates. As the value of Fi, the value of Small described in the above two documents was used. For ρ · ΣFi or M of the copolymer, calculate the sum of the values of ρ, ΣFi or M of each homopolymer of the monomer units constituting the copolymer, and multiply the mole fraction of the monomer unit by I was there. Further, the component (B) of the present invention is a polymer containing no aromatic vinyl compound unit in the polymer, which is a polymer containing no aromatic vinyl compound component in the polymer component. A composition using a polymer containing an aromatic vinyl compound unit has poor impact strength. As the aromatic vinyl compound, for example, styrene,
α-alkyl-substituted styrene such as α-methylstyrene,
Nuclear substituted alkyl styrenes such as p-methyl styrene are included. Further, the polymer having a solubility parameter (SP) of the component (B) used in the present invention of 8.45 to 8.70 is at least one of unsaturated carboxylic acid, unsaturated carboxylic acid ester or vinyl acetate. And a copolymer of ethylene with the vinyl monomer. Examples thereof include ethylene-unsaturated carboxylic acid copolymer, ethylene-
Unsaturated carboxylic acid ester copolymer, ethylene-vinyl acetate copolymer, ethylene-unsaturated carboxylic acid ester-
Examples thereof include vinyl acetate terpolymers and multi-component copolymers of ethylene and two or more kinds of unsaturated carboxylic acid esters.

Specific examples of unsaturated carboxylic acids include acrylic acid and methacrylic acid. Specific examples of the unsaturated carboxylic acid ester include ethyl acrylate, methyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, glycidyl acrylate, methyl methacrylate, ethyl methacrylate,
Examples thereof include 2-ethylhexyl methacrylate, stearyl methacrylate, and glycidyl methacrylate.
Preferred examples of the copolymer of ethylene with one or more vinyl monomers of unsaturated carboxylic acid, unsaturated carboxylic acid ester or vinyl acetate used in the present invention include ethylene-acrylic acid copolymer and ethylene-methacrylic acid. Copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methyl acrylate copolymer, ethylene-vinyl acetate, ethylene-methyl acrylate-glycidyl methacrylate copolymer Coalescing,
Examples thereof include ethylene-methyl methacrylate-glycidyl methacrylate copolymer and ethylene-vinyl acetate-glycidyl methacrylate copolymer. The proportion of the vinyl monomer in the copolymer is preferably 5 to 60% by weight.
Further, there is no limitation on the binding mode (for example, random, block, alternating) between the vinyl monomer and ethylene in the copolymer. The melt flow rate (according to JIS K7210, temperature 190 ° C., load 2.16 kgf) of the copolymer is not particularly limited, but may be 1 to 5
It is preferably about 00 g / 10 minutes.

To obtain the rubber-modified styrenic resin composition of the present invention, a predetermined amount of each component is dry blended with a mixing device such as a Henschel mixer or a tumbler, or a single or twin screw extruder, a Banbury mixer. A kneading machine such as the above may be used to sufficiently heat and knead at a temperature of 180 to 260 ° C., and then granulate. If necessary,
Additives such as antioxidants, heat stabilizers, ultraviolet absorbers, lubricants, antistatic agents, mineral oils and silicone oils can be used. These additives may be added during the above dry blending or kneading, or may be added during the polymerization step when synthesizing the rubber-modified styrene resin.

The injection-molded article of the rubber-modified styrene resin composition of the present invention can be obtained by using a generally used injection molding machine. The extrusion-molded product of the rubber-modified styrene resin composition of the present invention can be obtained by using a generally-used extrusion molding machine. The method of extruding the rubber-modified styrenic resin composition of the present invention into an extruded molded article is not particularly limited, but for example, it is melted by an extruder and then extruded from a T-die, or formed into a sheet by an extruder. After extrusion, a method of biaxially stretching by a tenter system or an inflation system can be used. The method for foaming the rubber-modified styrenic resin composition of the present invention to form a foam is not particularly limited, but for example, a decomposable foaming agent and a rubber-modified styrenic resin composition are melt-kneaded in an extruder, Method of foaming: Method of melting rubber-modified styrene-based resin composition with an extruder and directly pressing an evaporative foaming agent in the middle of the cylinder to knead and foam; Small pellets or beads of rubber-modified styrene-based resin composition A method of impregnating an evaporative foaming agent in an extruder or an aqueous suspension and foaming the impregnated pellets or beads with steam. Examples of the decomposition type foaming agent used here include azodicarbonamide, trihydrazinotriazine, and benzenesulfonyl semicarbazide. Evaporative blowing agents include propane, n-butane, i-butane, n
-Pentane, i-pentane, hexane, heptane, freon and the like can be mentioned.

The rubber-modified styrenic resin of the present invention is suitable for use in the fields of injection molded processed products, extruded sheet processed products and foam molded processed products. That is, specific applications include exterior materials for light electric appliances, office equipment, telephones, office automation equipment, and packaging materials such as food containers. In addition, a foam obtained by foaming a resin composition can be used as a so-called cushioning material that absorbs external impact applied to glass products and various precision equipment products and protects the products.

[0016]

The present invention will be described in detail with reference to the following examples, but the present invention is not limited to these examples. The measurement and evaluation methods are as follows. (1) Molding processability (presence or absence of bumps) <Injection molding> Using IS-150E manufactured by Toshiba, mold temperature 4
Flat plate injection molding was performed at 0 ° C. and a sample shape of 150 × 90 × 2 mm. At that time, the resin was retained in the cylinder at 240 ° C. for 1 hour and then injection-molded, and the presence or absence of hits on the flat plate surface was visually evaluated. <Extrusion Molding> A sheet processing machine having a thickness of 0.6 mm was extruded at a resin temperature of 240 ° C. using a sheet processing machine of 65 mmφ (Tanabe Plastic Machinery Co., Ltd., V65-S1000 type). At that time, put the resin in the cylinder at 240 ° C for 1
The sheet was extruded after being retained for a period of time, and the presence or absence of bumps on the sheet surface was visually evaluated. (2) Oil resistance Preheat the resin composition at 210 ° C. for 5 minutes, then 50 kg
/ Cm ² and 150 mm x 150 mm under pressure for 5 minutes
× 3mm press sheet is formed, then 20mm ×
A 150 mm × 3 mm test piece was cut out and used for measurement. Oil resistance is measured by fixing one end of the test piece to a jig,
Margarine (Neosoft manufactured by Snow Brand Milk Products Co., Ltd.) was applied to the surface of the test piece in a state of being distorted by 10 mm at a position of 100 mm from the fixed position, and allowed to stand at room temperature for 24 hours. evaluated.
No stress cracks were evaluated as ◯, and stress cracks were evaluated as x. (3) Impact strength of falling weight A flat plate with a thickness of 2 mm is injection-molded and a weight of 7.5 kg from a height of 80 cm is placed on the surface of the test piece using a "falling weight type graphic impact tester" from Toyo Seiki Seisakusho. The test piece is allowed to fall naturally and the test piece is completely broken or penetrated by a striker provided below the weight. The energy required for this was calculated. The measurement temperature was 23 ° C. The molding machine used was IS-150E manufactured by Toshiba, and the mold temperature was 40 ° C. and the sample shape was 150 mm × 90 mm × 2 mm. (4) Izod impact strength The test piece obtained by injection molding was JIS K71.
It measured according to 10. The thickness of the test piece is 3.0m
m, notched, and the measurement temperature was 23 ° C. (5) Gloss (surface appearance) A flat plate with a thickness of 2 mm is injection molded, and the central part is JIS
It was measured according to the standard of K7105 45 degree specular gloss measurement method. Toshiba IS-150E was used as the molding machine, the mold temperature was 40 ° C., and the sample shape was 150 mm × 90 m.
It was set to m × 2 mm. (6) Bending elastic modulus (rigidity) A test piece obtained by injection molding was JIS K72.
It measured based on 03. The measurement temperature was 23 ° C. (7) DuPont impact strength The resin sheet is at 23 ° C., the dart tip diameter is 1/8 inch R,
Using a device with a receiving diameter of 3/16 inch R, the energy at 50% destruction rate was measured. (8) Tensile Elastic Modulus (Rigidity) A resin sheet was used and measured according to ASTM D638. The measurement temperature was 23 ° C. The sample sampled in the resin flow direction was designated as MD, and the sample sampled in the direction perpendicular to the resin flow was designated as TD.

Examples 1 to 7 and Comparative Examples 1 to 4 The components shown in Tables 1 and 2 were mixed with a 40 mmφ extruder.
The pellets were obtained by melting at 20 ° C., kneading and granulating. The obtained pellets were injection molded into a test piece or a flat plate and evaluated. Further, the obtained pellets were press-molded and the oil resistance was evaluated.

Examples 8 to 10 and Comparative Examples 5 to 7 The components shown in Table 3 were dry blended, and a sheet processing machine of 65 mmφ (Tanabe Plastic Machine Co., Ltd., V65-S10) was used.
00 type) was extruded at a resin temperature of 240 ° C. to obtain a resin sheet having a thickness of 0.6 mm. The sheet physical properties were evaluated. Further, the components shown in Table 2 were melted at 220 ° C. with a 40 mmφ extruder, kneaded and granulated to obtain pellets. The obtained pellets were press-molded and the oil resistance was evaluated.

The (A) rubber-modified styrenic resin used was synthesized by the continuous bulk polymerization method as follows,
Its structure is shown in Table 4. A1: A mixed solution of 88% by weight of styrene, 7% by weight of polybutadiene, 3.5% by weight of ethylbenzene and 1.5% by weight of mineral oil was fed to a stirring type polymerization tank, and the temperature was 140 ° C. and the stirring speed was 15 rpm. 18% conversion rate
Was polymerized. Subsequently, the obtained mixed liquid was transferred to a full-filling type polymerization tank where polymerization was performed up to a conversion rate of 70%, and then the content was transferred to a degassing tank at 240 ° C. where volatile components were removed and then obtained. The polymer was passed through a melt extruder and a pelletizer to obtain pelletized rubber-modified styrene resin. A2: 89.8% by weight of styrene, 5.6% by weight of polybutadiene, and 3.6% by weight of ethylbenzene in a stirring type polymerization tank.
And a mixed solution consisting of 1% by weight of mineral oil,
Conversion rate 2 under conditions of temperature 140 ° C and stirring speed 60 rpm
Polymerized to 3%. Subsequently, the obtained mixed liquid was transferred to a full-filling type polymerization tank where polymerization was performed up to a conversion rate of 70%, and then the content was transferred to a degassing tank at 240 ° C. where volatile components were removed and then obtained. The polymer was passed through a melt extruder and a pelletizer to obtain pelletized rubber-modified styrene resin.

As the ethylene-unsaturated carboxylic acid ester copolymer (B), an ethylene-methyl methacrylate copolymer was used. Sumitomo Chemical Co., Ltd. Acryft WM403 (methyl methacrylate content 38%, melt flow rate 1
5 g / 10 minutes) and described as B1 in the table. The component (B) used is as follows. B1: Ethylene-methyl methacrylate copolymer (manufactured by Sumitomo Chemical Co., Ltd., trade name: Acrif WM403, methyl methacrylate content 38% by weight, melt flow rate 15 g)
/ 10 minutes), B2: ethylene-ethyl acrylate copolymer (ethyl acrylate content 18% by weight, melt flow rate 7 g)
/ 10 minutes), B3: ethylene-vinyl acetate copolymer (Sumitomo Chemical Co., Ltd., trade name Summitate RB-11, vinyl acetate content 41)
% By weight, melt flow rate 60 g / 10 minutes), B4: ethylene-vinyl acetate copolymer (Sumitomo Chemical Co., Ltd., trade name Sumitate HA-20, vinyl acetate content 20)
% By weight, melt flow rate 20 g / 10 minutes), B5: polypropylene (manufactured by Sumitomo Chemical Co., trade name Nobren AD571, melt flow rate 0.2 g / 10)
Min), B6: styrene-acrylonitrile copolymer (manufactured by Mitsubishi Monsanto Kasei, trade name Sanrex SAN-R, acrylonitrile content 26% by weight, melt flow rate 0.9).
g / 10 minutes). The melt flow rate was measured according to JIS K7210 at a temperature of 190 ° C. and a load of 2.16 kgf. The solubility parameters (SP) of these components (B) are shown in Table 5.

The results show the following. In Tables 1 and 2, the compositions of Examples 1-7 of the present invention were tested for impact strength,
Excellent oil resistance and molding processability, other physical properties are Comparative Examples 1 to 4
Is equivalent to On the other hand, the composition of Comparative Example 1 containing no component (B) is inferior in oil resistance and impact strength. The composition of Comparative Example 2 in which the soft component particles of the component (A) have a small average particle size is inferior in oil resistance and impact strength. The compositions of Comparative Examples 3 and 4 containing as the component (B) a polymer having an SP outside the specified range were inferior in impact strength. Next, in Table 3, the compositions of Examples 8 to 10 of the present invention are excellent in impact strength, oil resistance and molding processability, and other physical properties are the same as those of Comparative Examples 5 to 7. On the other hand, the composition of Comparative Example 5 containing no component (B) is inferior in oil resistance and impact strength. The compositions of Comparative Examples 6 and 7 which did not contain the component (B) but contained the component (C) were inferior in moldability and oil resistance.

[0022]

[Table 1] ─────────────────────────────── Comparative Examples Examples Examples Examples Examples Comparative Examples 1 1 2 3 2 Mixing (parts by weight) (A) ^{* 1} 100 100 100 100 100 A1 A1 A1 A1 A2 (B) ^{* 2} 0 5 11 20 5 B1 B1 B1 B1 Evaluation Molding process Mold generation Injection molding No No No No No Oil resistance × ○ ○ ○ × Drop weight impact strength (J) 9.1 8.5 10.2 12.1 5.4 Izod impact strength 9.0 10.6 13.1 10.4 5.9 (kgf ・ cm / cm ² ) Gloss (%) 32.0 38.9 43.1 35.5 96.9 Flexural modulus 14900 13900 12700 10500 23400 (kgf) / cm ² ) ─────────────────────────────── * 1: (A) Rubber-modified styrene resin * 2: ( B) Polymers shown in Table 5

[0023]

[Table 2] ─────────────────────────────────── Examples Examples Examples Examples Examples Comparative Examples Comparative Example Blend (parts by weight) 4 5 6 7 3 4 (A) ^{* 1} 100 100 100 100 100 100 A1 A1 A1 A1 A1 A1 A1 (B) ^{* 2} 11 11 20 20 11 11 B2 B3 B3 B4 B5 B6 Evaluation Molding Generation Injection molding No No No No No No Oil resistance ○ ○ ○ ○ ○ × Drop weight impact strength (J) 10.0 9.3 10.0 9.8 1.1 2.1 Izod impact strength 13.1 12.0 9.6 9.6 3.5 3.9 (kgf ・ cm / cm ² ) Gloss (% ) 40.5 35.0 34.9 33.1 31.5 30.5 Flexural modulus 12800 12300 10300 10800 15300 15000 (kgf / cm ² ) ───────────────────────────── ─────── * 1: (A) Rubber-modified styrene resin * 2: (B) Polymer shown in Table 5

[0024]

[Table 3] ─────────────────────────────────── Comparative Examples Comparative Examples Comparative Examples Examples Examples Examples Example 5 6 7 8 9 10 Compounding (parts by weight) (A) ^{* 1} 100 100 100 100 100 100 A1 A1 A1 A1 A1 A1 (B) ^{* 2} 0 0 0 3 11 25 B1 B1 B1 (C) ^{* 3} 0 11 25 0 0 0 C1 C1 Evaluation Molding process Blast generation Extrusion molding No Yes Yes No No No Oil resistance × × × ○ ○ ○ DuPont drop weight impact strength 5.3 16.5 19.9 9.3 13.8 12.2 (kgf ・ cm / mm) Tensile elastic modulus MD 9700 8700 6800 9500 7800 5100 (kgf / cm ² ) TD 8100 6200 3200 7900 5600 2600 ───────────────────────────────── ─── * 1: (A) Rubber-modified styrene resin * 2: (B) Polymer shown in Table 5 * 3: (C) Styrene-butadiene-styrene block copolymer (C1: butadiene content = 60% by weight) , Asahi Kasei, Name Tufprene A)

[0025]

[Table 4]

[0026]

[Table 5] ─────────────────────────── B1 B2 B3 B4 B5 B6 Density ρ g / cm ³ 0.96 0.93 0.97 0.94 0.90 1.10 Repeat Molecular weight of unit M 38.5 32.2 38.7 32.4 42.0 83.9 ΣFi 341 298 343 298 375 768 SP 8.50 8.61 8.60 8.65 8.04 10.07 ────────────────────────── ─

Claims (9)

[Claims] 1. A rubber-modified styrene resin composition containing 100 parts by weight of the following component (A) and 0.1 to 250 parts by weight of the component (B). (A): A rubber-modified rubber containing 5 to 35% by weight of soft component particles, having an average particle diameter of the soft component particles of more than 2.5 μm and 5 μm or less and a swelling degree of the soft component particles of 3 to 30. Styrenic resin (B): solubility parameter (SP) is 8.45 to 8.7.
A polymer which is 0 and does not contain an aromatic vinyl compound unit in the polymer. 2. The component (B) is a copolymer composed of ethylene and at least one vinyl monomer selected from unsaturated carboxylic acids, unsaturated carboxylic acid esters or vinyl acetate.
The resin composition as described in the above. 3. The resin composition according to claim 1, wherein the component (B) is an ethylene-unsaturated carboxylic acid ester copolymer. 4. The resin composition according to claim 1, wherein the component (B) is an ethylene-methyl methacrylate copolymer. 5. The resin composition according to claim 1, wherein the component (B) is an ethylene-vinyl acetate copolymer. 6. The resin composition according to claim 1, wherein the component (B) is a copolymer composed of ethylene and two or more different unsaturated carboxylic acid esters. 7. An injection-molded article using the rubber-modified styrenic resin composition according to claim 1, claim 2, claim 3, claim 4, claim 5 or claim 6. 8. An extrusion molded product using the rubber-modified styrene resin composition according to claim 1, claim 2, claim 3, claim 4, claim 5 or claim 6. 9. A foam-molded article using the rubber-modified styrenic resin composition according to claim 1, claim 2, claim 3, claim 4, claim 5 or claim 6.