Polybutylene terephthalate resin composition and thin molded article

Abstract

The present invention provides a polybutylene terephthalate resin composition which is free from bleeding and other problems, and improves the flowability (melt-flowability) while maintaining the characteristics such as mechanical strength or toughness. To 100 parts by weight of a composition composed of 50 to 90% by weight of (A) a polybutylene terephthalate resin and 10 to 50% by weight of (B) inorganic filler, is blended 0.05 to 5 parts by weight of (C) a glycerin fatty acid ester being composed of glycerin and / or a dehydrated condensate thereof and a fatty acid having 12 or more carbon atoms and having 200 or more hydroxyl value determined by the method specified in the description.

Description

TECHNICAL FIELD[0001]The present invention relates to a polybutylene terephthalate resin composition having excellent flowability and to a thin-walled molded article thereof, and more particularly to a polybutylene terephthalate resin composition having excellent flowability and being suitable for the injection-molded article for electrical and electronic parts and the like, such as a switch, a capacitor, a connector, an integrated circuit (IC), a relay, a resister, a light-emitting diode (LED), a coil bobbin, a peripheral device thereof, and a housing thereof, and to a thin-walled molded article thereof.BACKGROUND ART[0002]Since polybutylene terephthalate resin has excellent mechanical characteristics, electrical characteristics, heat resistance, weatherability, water resistance, chemical resistance, and solvent resistance, the resin is widely used in various applications as engineering plastics, in automobile parts, electrical and electronic parts, and the like. Such polybutylene ...

AI Technical Summary

Benefits of technology

[0014]The polybutylene terephthalate resin composition according to the present invention has excellent mechanical strength and toughness, and excellent flowability during melt-molding. Owing to the characteristics, the polybutylene terephthalate resin composition according to the present invention is suitable for electrical and electronic parts such as a switch, a capacitor, a connector, an integrated circuit (IC), a relay, a resister, a light-emitting diode (LED), a coil bobbin, a peripheral device thereof, and a housing thereof.

Problems solved by technology

Although the composition containing an inorganic filler such as glass fiber has high mechanical strength and stiffness, when it is used as thin-walled plate-like or box-like molding articles, for example, micro-switch casing, small coil bobbin, thin-walled connector, and disk cartridge shutter, the composition raises problems such as insufficient molding (insufficient filling in the mold for manufacturing molded article) caused by the decreased flowability resulted from the blending of reinforcing material, and increase in the generation of warp caused by the non-uniform flow of resin.

The resin composition of Patent Document 1 is, however, inferior in elongation and the like of the resin compared with the case where sole high-viscosity polybutylene terephthalate is used.

The resin composition described in Patent Document 2, however, shows a tendency of having somewhat inferior mechanical strength compared with the case where the flowability-improving agent is not added.

However, the use of the flowability-improving agent for resin may induce bleeding and separation of surface layer of the molded article, and further a decrease in the mechanical strength is unavoidable.

However, Patent Document 3 does not give a description of the flowability of the resin composition at all.