Sumitomo Chemical Company, Limited

Koichi Mizumoto

Hiroshi Harada

Tohru Nagashima

Satoshi Sekimura

Manabu Hirakawa

Kazuo Hayatsu

Shintaro Saito

The present invention is related to a method for producing a resin composition including feeding a resin (A), a fibrous filler (B), and a particulate filler (C) which is harder than the fibrous filler (B) to an extruder, and melt-kneading to extrude a kneaded material, the resin composition comprising a fibrous filler (B) which is 140 &#x3bc;m or less in weight average fiber length. According to the present invention, a production method with high versatility is provided in which a resin composition containing the fibrous filler having the weight average fiber length of 140 &#x3bc;m or less is effectively produced.

Method for producing resin composition

A method is provided for producing a resin composition in which the fiber length of the fibrous filler contained in the resin composition is controlled. The method includes a step of feeding a resin (A) and a fibrous filler (B) to an extruder, melt-kneading and then extruding them. The extruder includes a cylinder, a screw mounted in the cylinder, a main feed port provided in the cylinder, and a side feed port provided rearwards from the main feed port in the extrusion direction. Part of the resin (A) and part of a fibrous filler (B) having a weight-average fiber length of not less than 1 mm are fed through the main feed port and the rest of the resin (A) and the rest of the fibrous filler (B) having a weight-average fiber length of not less than 1 mm are fed through the side feed port.

The present invention provides for a resin molded article comprising a liquid crystalline polymer and a fibrous filler, the article having a surface with difference of 0.4 &#x3bc;m or smaller in a surface roughness expressed by Ra value measured before and after repeating 30 times the operation of pasting and peeling a tape having an adhesive power of 4.0 N/mm. The resin molded article is excellent in mechanical strength when used in an electric/electronic component or in an optical apparatus.

Resin molded article and method for producing the same

Process for producing thermotropic liquid crystalline polymer

Method of producing an aromatic polyester

Provided is a liquid crystalline polyester resin for extrusion molding having a solder heat resistant temperature of 250.degree. C. or more, wherein the ratio ((viscosity 2b)/(viscosity 1b)) of the melt viscosity (viscosity 1b) under a shearing speed of 1000/sec at the flow initiation temperature and the melt viscosity (viscosity 2b) under the same shearing speed at a temperature 20.degree. C. higher than the flow initiation temperature is from 0.10 to 0.70. The extrusion molding material of the above-described liquid crystalline polyester resin has excellent heat resistance, and can provide an extrusion molded article, especially a film having excellent appearance.

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Tsukuba, Japan

Koichi Mizumoto