JPH06192502A - Thermosetting resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition having impact resistance and chemical resistance, especially high resistance to oil, comprising a composition composed of a styrenic resin and a polypropylene-based resin. CONSTITUTION:100 pts.wt. resin composition comprising (A) 5-95 wt.% polystyrene resin and (B) 95-5 pts.wt. polypropylene-based resin are blended with (C) 0.5-30 pts.wt. hydrogenated block copolymer obtained by hydrogenating >=70wt.% aliphatic double bond of a styrene-butadiene-styrene block copolymer (SBS) having >=70wt.% 1,2 vinyl bond amount of butadiene block to give a composition.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermoplastic resin composition having excellent chemical resistance, moldability and impact resistance.

[0002]

2. Description of the Related Art Styrene resin is a resin having high moldability and secondary workability and high rigidity. Polypropylene has high impact resistance, high chemical resistance and low water vapor permeability. There is a characteristic.

Although many attempts have been made to blend these both with each other to obtain a resin excellent in impact resistance, chemical resistance and molding processability, there has been no compatibilizer for appropriately compatibilizing the both. , The properties of the obtained alloy were inadequate. Among them, hydrogenated styrene-butadiene-styrene block copolymer (SBS), styrene-isoprene-styrene (SIS) block copolymer, that is, styrene-ethylene propylene-styrene (SEBS).
When the block copolymer and the styrene-ethylene propylene-styrene (SEPS) block copolymer were added as compatibilizers, the compatibility was relatively good, but the properties of the obtained alloy were not sufficient. . Since conventional commercially available SEBS attaches great importance to the property as an elastomer, it is produced by hydrogenating SBS having a ratio of 1,2-bonds and 1,4 bonds of a butadiene block of about 1/1. Further, according to Japanese Patent Publication No. 62-12812, a composition of a polyolefin resin and a polystyrene resin is obtained by using a butadiene block in which about 35 to 55 mol% of butadienunit has a 1,2-vinyl bond is hydrogenated. Although it is disclosed that the impact resistance and the cracking resistance of the product are improved, SEBS obtained by hydrogenation here has a molar ratio of ethylene unit and butylene unit of 2: 1 and is When used as a compatibilizer for blending with polypropylene, the compatibilizing effect was not sufficient.

[0004]

DISCLOSURE OF THE INVENTION The present inventors have found that a block copolymer obtained by hydrogenating SBS having a 1,2-vinyl bond content of 70% or more in a butadiene block is compatible with polystyrene resin and polypropylene. They have found that they are suitable as an agent and have reached the present invention.

That is, the present invention is based on 100 parts by weight of a resin composition comprising (A) polystyrene resin 5 to 95% by weight (B) polypropylene resin 95 to 5% by weight. Vinyl bond amount is 70
0.5 to 30 parts by weight of a hydrogenated block copolymer obtained by hydrogenating 70% or more of aliphatic double bonds of a styrene-butadiene-styrene block (SBS) copolymer having a content of at least 60% is added. It is a thermoplastic resin composition characterized by the following.

The polystyrene resin used as the component (A) in the present invention is a high impact polystyrene (HI impact polystyrene / HI) obtained by graft-polymerizing a styrene homopolymer, a diene rubber elastomer and a styrene monomer.
PS), a copolymer of styrene and α-methylstyrene, chlorostyrene, or the like, or a mixture thereof, and further, such as a styrene-based monomer and an unsaturated nitrile, an α, β-monoolefinic unsaturated carboxylic acid ester. Impact resistance obtained by copolymerization with vinyl monomers or graft copolymerization of these vinyl monomers with diene rubber elastomer, acrylic rubber containing unsaturated group, chlorinated polyethylene, ethylene-vinyl acetate copolymer, etc. Resin, etc.

The polypropylene resin used as the component (B) of the present invention is a homopolymer of propylene, a copolymer of propylene and a monomer copolymerizable with propylene, or a mixture thereof. Examples of the component copolymerizable with propylene include ethylene, 1-butene, 1-pentene, 3-methyl-1-pentene, and 4-methyl-1.
-Α-olefins such as pentene and maleic acid, acrylic acid, methacrylic acid, fumaric acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, mesaconic acid, angelic acid, ethylenically unsaturated acids such as maleic anhydride, anhydrous There are ethylenically unsaturated acid anhydrides such as citraconic acid and itaconic anhydride, acrylic acid esters and methacrylic acid esters, and ethylenically unsaturated acid esters such as vinyl esters of carboxylic acids.

The block copolymer used as the component (C) of the present invention is produced by first making a styrene-butadiene-styrene block copolymer and then hydrogenating it. These block copolymers can be produced by a known production method. For example, US Pat. No. 359.
It is described in detail in Japanese Patent No. 5942, and this patent is
1 illustrates a method of making a block copolymer including a suitable method of hydrogenating a precursor polymer. SBS linear polymers are prepared by continuously adding the desired monomer into a reaction vessel with an initiator such as lithium-alkyl or dilithiostilbene. It can also be produced by coupling the SB diblock copolymer with a bifunctional coupling agent. As a method of adjusting the amount of 1,2-vinyl bonds in the butadiene block, polymerization of a solvent having a high polarity such as tetrahydrofuran (THF) is used to obtain 1,2 vinyl bonds in the butadiene block.
A block copolymer having a high vinyl bond content can be produced. Further, by using a cobalt catalyst even in a solvent having low polarity, a block copolymer having a large amount of 1,2 bonds can be produced. In the present invention, the amount of 1,2-vinyl bonds is 70% or more, and if it is less than 70%, the compatibility of the final composition decreases and the oil resistance decreases, which is not preferable.

The preferred block copolymer used in the present invention has a styrene block molecular weight of 500 to 30,000.
And the butadiene block has a molecular weight of 1000 to 50.
It is a hydrogenated SBS block copolymer of 000. Dissolve the precursor block copolymer in an inert solvent and hydrogenate at least 70% or more of the aliphatic double bonds in the presence of a hydrogenation catalyst at 20 to 150 ° C. and 1 to 100 kg / cm ² of pressurized hydrogen. Meanwhile, a part of the alkenyl arene aromatic double bond is hydrogenated.

The blending ratio of each component of the present invention is as follows:
The compounding ratio of the component (A) and the component (B) is 5 to 95/95.
It is 5. It is possible to increase the compounding ratio of the component (A) when it is desired to impart high rigidity to the material, and increase the compounding ratio of the component (B) when importance is attached to chemical resistance and impact resistance. The amount of component (C) added is 0.5 to 30 parts by weight per 100 parts by weight of component (A) + component (B). 0.5
If it is less than parts by weight, the compatibilizing effect is slight and the physical properties of the composition are not significantly improved. Also, if it exceeds 30 parts by weight,
The composition has low rigidity and is not economical.

Stabilizers and pigments may be added to the resin composition of the present invention as long as the characteristics of the present invention are not impaired.

The resin composition of the present invention can be produced by dry-blending all the components and then heat-melting and mixing with a single-screw or twin-screw extruder.

[0013]

EXAMPLES The present invention will be further described below with reference to examples. The test method was performed according to the following method.

(1) Izod impact resistance The resin composition is 63.5 mm × 12.7 mm × 6.4 mm
Was injection-molded into a test piece of and the Izod impact value was measured according to ASTM D258. (2) Tensile test The resin composition was injection-molded into a type 1 test piece described in ASTM D638, and measured according to ASTM D638. Crosshead speed 5mm / min. (3) Evaluation of rigidity The resin composition was molded into 127 × 12.5 × by injection molding.
6.3 Molded into test pieces of each mm, and subjected to the three-point bending test method (AS
The flexural modulus was measured according to TM D790). (4) Oil resistance 1000 psi on a strand sample with a diameter of about 3 mm
Was applied, margarine was applied to a part of the strand, and the time until the strand was broken was measured. Unit: minutes.

Reference Example 1 Tetrahydrofuran (4,000 g), styrene monomer (220 g) and n-butyllithium (0.7 g) were added to an aluminum autoclave and polymerized at 70 ° C. for 60 minutes, and then 1,3-butadiene monomer (560 g) was added to the autoclave for 15 minutes.
Polymerize for 0 minutes and finally 220 g of styrene monomer
Was added and polymerized for 60 minutes, a large amount of methanol was added to stop the reaction, and then a styrene-butadiene-styrene block copolymer was obtained. The obtained block copolymer had a bound styrene content of 41% and 1,2 in the butadiene block.
-Vinyl bond content was 86% and number average molecular weight was 92000.

This copolymer was diluted with purified and dried cyclohexane to adjust the polymer concentration to 5% by weight. 1000 g of the above polymer solution was charged into a sufficiently dried 2 liter autoclave equipped with a stirrer, deaerated under reduced pressure, and then replaced with hydrogen.
The temperature was maintained at 30 ° C. with stirring. Di-p-tolylbis (η-
50 ml of a cyclohexane solution containing 0.2 mmol of cyclopentadienyl) titanium and 10 ml of a cyclohexane solution containing 0.8 mmol of n-butyllithium were mixed at 0 ° C. under a hydrogen pressure of 3 kg / cm ² , and the copolymer solution in the autoclave was mixed. Added to. 5.0 kg / with stirring
The hydrogenation reaction was performed by continuously supplying dry hydrogen gas of cm ² for 2 hours. After returning the reaction solution to normal temperature and pressure, the catalyst was deactivated. According to ¹ H-NMR analysis, the obtained polymer was found to have 85% or more of butadiene units hydrogenated, and the hydrogenation of styrene units was less than 5%.

The resins used in the examples are as follows. General-purpose polystyrene (GPPS) Sumitomo Chemical Sumibrite 4 Rubber-modified impact-resistant polystyrene (HIPS) Sumitomo Chemical Sumibrite 500HG-S Acrylonitrile-butadiene-styrene copolymer (A
BS) Daicel Chemical Industries Cebian V660SF Acrylonitrile-styrene copolymer (AS) Daicel Chemical Industries Cebian N ethylene-propylene copolymer (EPR) Nippon Synthetic Rubber EP07P Polypropylene (PP) Nippon Petrochemical Nisseki Polypro J130G Styrene-ethylene butadiene -Styrene block copolymer (SEBS) Asahi Kasei Tuftec H1041 (1,2 vinyl bond amount 3
5%).

Examples 1 to 7 and Comparative Examples 1 and 2 30 m after dry blending each resin with the compounding ratio shown in the table
Extruder with mφ vent, cylinder temperature 150 ℃ ～ 210
Melt extrusion was carried out at 0 ° C., and the obtained strand was pelletized. An oil resistance test was performed on the resulting strands and pellets were injection molded and tested according to the method described above. The results are shown in Table 1. 1, manufactured in the reference example
The one using a hydrogenated block copolymer having a vinyl bond content of 86% has greatly improved impact strength and oil resistance.

[0019]

[Table 1]

[0020]

The composition of the present invention has improved compatibility between polystyrene resin and polypropylene resin, and improved chemical resistance and impact resistance.

Claims (1)

[Claims] 1. A 1,2-vinyl bond content of (C) butadiene block to 100 parts by weight of a resin composition comprising (A) polystyrene resin 5 to 95% by weight (B) polypropylene resin 95 to 5% by weight. Is 70
0.5 to 30 parts by weight of a hydrogenated block copolymer obtained by hydrogenating 70% or more of aliphatic double bonds of a styrene-butadiene-styrene block (SBS) copolymer having a content of at least 60% is added. A thermoplastic resin composition comprising: