JPS62149749A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. which gives moldings having excellent mechanical strength, consisting of a polyamide resin, a styrene polymer, an inorg. filler and a specified thermoplastic styrene elastomer. CONSTITUTION:100pts.wt. resin compsn. consisting of 5-95wt% polyamide resin (A) (e.g., nylon 6) and 50-5wt% styrene polymer (B) composed of at least 25wt% repeating unit derived from an arom. vinyl compd. of the formula (wherein R is H or a 1-4 C alkyl group; Z is halogen or a 1-4 C alkyl group; p is 0-5) is blended with 5-100pts.wt. inorg. filler (C) such as glass fiber, carbon fiber, metallic fiber, etc., and 0.01-5pts.wt. thermoplastic styrene elastomer copolymer (D) having a group selected from among COOH, acid anhydride, acid amide, imide, carboxylic ester, epoxy, NH2 and OH groups attached to its elastomer moiety.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention provides a molded article with improved mechanical strength (prior art) by blending polystyrene or a copolymer mainly composed of styrene into a polyamide resin. It is known to obtain resin compositions which give molded articles with improved oil and heat resistance. However, molded articles made from this resin composition are insufficient in mechanical strength and dimensional accuracy. Although dimensional accuracy is slightly improved by blending maleic anhydride-modified polystyrene with polyamide, mechanical strength is still insufficient.

In order to overcome these drawbacks, it is known to add inorganic fillers such as glass fibers, but this results in the drawback that the molded product becomes brittle.

(Problems to be Solved by the Invention) The present invention provides a resin composition that does not have the above-mentioned drawbacks and provides a molded article with significantly improved mechanical strength.

(Means for solving the problem) We have discovered that the mechanical strength of molded products can be significantly improved by adding a small amount of a styrene-based thermoplastic elastomer copolymer that has a group such as a poquin group in a part of the nidistomer. Completed the invention.

That is, the present invention provides (a) polyamide resin 50-95
Weight% (1)) Styrenic polymer 5~
50% by weight and (d) a group consisting of a carboxy group, an acid anhydride group, an acid amide group, an imide group, a carboxylic acid ester group, an epoxy group, an amino group, and a hydroxyl group in the elastomer part of the styrene-based thermoplastic elastomer copolymer. A thermoplastic resin composition containing 0.01 to 5 parts by weight of a styrenic thermoplastic elastomer copolymer having a group selected from 0.01 to 5 parts by weight.

In the present invention, the polyamide resin is a polymer containing 100NH- bonds in the repeating unit, and typical examples thereof include 4-nylon, 6-nylon, 6.6-nylon, 1
1-nylon, 12-nylon o7.6.10-f ylon,
Polyamides from totrimethylhexamethylene diamino terephthalate, polyamides from adipic acid and metaxylylene diamino color, adipic acid and azelaic acid and 2.
Examples include polyamides made from 2-his(p-aminocyclohexyl)-propane, polyamides made from terephthalic acid and 4°4'-diaminodicyclohexylmethane, and the like.

The styrenic polymer used in the present invention is also known per se and has the general formula (where R is hydrogen or an alkyl group having 1 to 4 carbon atoms, and 2 is a halogen atom or (in which p is an integer of 0 to 5), the polymer has at least 25% or more of repeating structural units derived from a vinyl aromatic compound represented by It has to be something. Such styrenic polymers include, for example, homopolymers of styrene or its derivatives, as well as natural or synthetic elastomeric materials such as polybutadiene, polyisoprene, butyl rubber, EPDM, ethylene-propylene copolymers, natural rubber, shrimp chlorohydrin, etc. Modified styrenic polymers, and furthermore,
Styrene-containing copolymers, such as styrene-acrylonitrile copolymer (sAN), styrene-methyl methacrylate copolymer, styrene-α-methylstyrene copolymer, styrene-hinyltoluene copolymer, styrene-butadiene copolymer styrene-maleic anhydride copolymer, styrene-acrylonitrile-butadiene copolymer (
ABS). Preferred styrenic polymers for the present invention are homopolystyrene and ABS.
It is.

The weight of the styrenic polymer should be in the range of 5 to 50% by weight based on the total weight of the polyamide resin and styrenic polymer.

If this is less than 5 times, the effects of reducing water absorption and improving impact strength, which are the effects of adding styrenic polymer, cannot be fully achieved. On the other hand, if this exceeds 50% by weight, the inherent advantages of polyamide resin, such as chemical resistance and abrasion resistance, will be lost, and fibers such as carbon fiber, metal fiber, asbestos, calcium carbonate, Merck, barium sulfate, and glass beads will be lost. Commonly used materials can be used, such as. In particular, glass fa, fibers and carbon fibers are preferred, and the amount is 5 to 100 parts by weight per 100 parts by weight of the total of the styrene polymer. If this amount is less than 5 parts by weight, the reinforcing effect will be small, while if it exceeds 100 parts by weight, the molded product will become brittle.

In the present invention, a component that increases the mechanical strength of a molded article when added in a small amount (namely, the elastomer of a styrene-based thermoplastic elastomer copolymer) -r has a carboxy group, an acid anhydride group, an acid amide group, or an imide group. In the styrenic thermoplastic elastomer copolymer having groups selected from the group consisting of hydroxyl groups, carboxylic acid ester groups, epoxy groups, amino groups and hydroxyl groups, the styrenic thermoplastic elastomer has a diene rubber center block such as polybutadiene and a diene rubber center block such as polystyrene. It is a block copolymer with polyvinyl aromatic hydrocarbon end blocks, or a hydrogenated product of such a block copolymer. The end blocks of this styrenic elastomer are, for example, vinyl aromatic hydrocarbon polymers made of styrene, α-methylstyrene, vinylstyrene, vinylxylene, ethylvinylxylene, vinylnaphthalene, etc., and mixtures thereof. It may be a polar polymer or a different type of polymer. The central block can be, for example, butadiene, propylene, isoprene, 1
．． It is a rubbery polymer consisting of 3-pentadiene, 2,3-dimethylbutadiene, etc., and mixtures thereof. Additionally, block copolymers can have either linear or teleradial structures. Further, until at least 8°, preferably 90° or more of the aliphatic double bonds in the styrenic thermoplastic elastomer become saturated bonds (
That is, styrenic thermoplastic elastomers that have been hydrogenated until the degree of unsaturation is reduced to 10 degrees or less of the original degree of unsaturation are also used as styrenic thermoplastic elastomers. The ratio and average molecular weight of the components of these block copolymers can vary over a wide range, but the molecular weight of the central block should be greater than the total molecular weight of the end blocks. For example, end blocks with an average molecular weight of about 4,000 to 115,000 and about 2,000 (1 to
Preferably, the block copolymer is formed from a central block having an average molecular weight of 450,000. It is even more preferred that the end blocks have an average molecular weight of about 8,000 to 60,000, while the central block has an average molecular weight of about 50,000 to 300,000. The terminal block is
It preferably constitutes 2 to 63% by weight of the entire block copolymer, more preferably 5 to 30% by weight.

A preferred copolymer is a styrenic thermoplastic elastomer having a polybutadiene-type central block, in which 55 to 55, more preferably 40 to 50, butadiene carbon atoms are vinylhomopolystyrene and the central block is polybutadiene, or it is hydrogenated. It was added.

In the component (d) used in the present invention, the elastomer part K of the styrenic thermoplastic elastomer copolymer as described above, a carboxyl group, an acid anhydride group, an acid amide group, an imide group, a carboxylic acid ester group, an epoxy group , amino groups and hydroxyl groups, preferably carboxy groups and/or acid anhydride groups. Further, the styrene moiety may contain the above groups or other groups such as an alkyl group or a halogen atom. Most preferably, a styrene-butadiene elastomer copolymer having a tylboxy group in the butene moiety is used as component (i), for example the commercially available Kraton DX-1300 (trademark; 5he11 Company) can be used.

The amount of component (d) is 0.01 to 5 parts by weight based on the weight of components (a) + (b). If this amount exceeds 5 parts by weight, the mechanical strength will actually decrease. If this amount is less than 0.011 parts by weight, the effect of adding component (d) will not be achieved.

The present invention will be further explained below with reference to Examples.

Example A thermoplastic resin composition having the composition shown in Table 1 below was extruded into pellets at 290° C. using a twin screw extruder equipped with a vacuum vent. This pelletized resin was molded into a molded body using an injection molding machine set at a cylinder temperature of 250°C, an injection pressure of 800°C and a mold temperature of 80°C.

The molded body was tested for tensile strength and A according to ASTM D-658.
Bending strength and bending elasticity were evaluated according to STMD-790. The results are shown in Table 1.

From the table, it can be seen that the molded articles made using the composition of the present invention have excellent mechanical strength.

Claims (1)

[Scope of Claims] 1. (c) Inorganic filler 5 to 100 parts by weight based on 100 parts by weight of a resin composition consisting of (a) polyamide resin 50 to 95 parts by weight (b) styrene polymer 5 to 50 parts by weight and (d) the elastomer portion of the styrenic thermoplastic elastomer copolymer is selected from the group consisting of a carboxy group, an acid anhydride group, an acid amide group, an imide group, a carboxylic acid ester group, an epoxy group, an amino group, and a hydroxyl group. Styrenic thermoplastic elastomer copolymer having 0.01-5
A thermoplastic resin composition comprising parts by weight. 2. The thermoplastic resin composition according to claim 1, wherein the group of component (d) is selected from the group consisting of a carboxy group and an acid anhydride group. 3. The thermoplastic resin composition according to claim 1, wherein component (d) is a styrene-butadiene elastomer copolymer having a carboxyl group and/or an acid anhydride group.