Production method for injection-molded article and injection-molded article

Abstract

Provided is a production method for an injection-molded article, that has excellent productivity and is capable of obtaining a molded article with high crystallinity while reducing the number of burrs produced. A polyarylene sulfide resin composition is injection molded at a metal mold temperature of up to 100°C, using a metal mold having a thermal insulation layer configured from porous zirconia formed on the inside surface thereof. It is desirable that the thermal insulation layer is formed using thermal spraying. In addition, the desirable thermal conductivity of the thermal insulation layer is up to 2 W / m·K. The desirable thickness of the thermal insulation layer is at least 200 µm.

Description

technical field [0001] The present invention relates to a method for producing an injection-molded article obtained by injection-molding a polyarylene sulfide-based resin composition. Background technique [0002] Polyarylene sulfide (hereinafter abbreviated as PAS) resin represented by polyphenylene sulfide (hereinafter abbreviated as PPS) resin has high heat resistance, mechanical properties, chemical resistance, dimensional stability, and flame retardancy. sex. Therefore, PAS resins are widely used as materials for electrical and electronic equipment components, automotive equipment components, chemical equipment components, etc., especially for applications where the temperature of the operating environment is high. [0003] However, since the crystallization rate of PAS resin is slow and the glass transition temperature is high, it is difficult to increase the crystallinity of the surface of the molded article, and it is easy to form a locally uneven crystal structure....

AI Technical Summary

Problems solved by technology

[0003] However, due to the slow crystallization rate and high glass transition temperature of PAS resin, it is difficult to increase the crystallinity of the surface of the molded product, and it is easy to form a locally uneven crystal structure

Therefore, the surface of molded products containing PAS resin tends to be uneven in both appearance and structure

[0004] In addition, when the crystallinity of the surface of the molded product cannot be improved, the following problems may occur: the surface hardness cannot be improved and it becomes difficult to eject from the mold, or due to the increase in post-shrinkage, depending on the use environment of the molded product, there may be problems that Surface roughness, dimensional changes, warpage, etc.

However, even if the method described in this patent document 6 is adopted, the condition of mold temperature needs to be set to 100°C or higher.

In addition, there are problems such as generation of gas during molding and melting, rough molding surface, and lowering of mechanical properties of molded products, as in the method of adding phosphate ester mentioned above.

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