Sumitomo Chemical Company, Limited

Satoshi Sekimura

Hiroshi Harada

Koichi Mizumoto

Hirokazu Matsui

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 for producing a resin composition using an extruder, the extruder having a cylinder and a screw disposed inside the cylinder, the cylinder being provided with a main feed port and further optionally provided with a side feed port disposed downstream in an extrusion direction from the main feed port, and the method comprising: supplying a resin (A) in the total amount to the extruder from the main feed port; supplying a fibrous filler (B), whose a weight average fiber length is 1 mm or more, in the total amount to the extruder from the main feed port, or, with the extruder being provided with the side feed port, supplying the fibrous filler (B) partly to the extruder from the main feed port and the remainder to the extruder from the side feed port; melt-kneading the supplied resin (A) and the fibrous filler (B); and extruding the melt-kneaded material.

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.

An object is to provide a liquid crystal polyester resin composition capable of producing a molding in which the generation amount of particles is sufficiently reduced. The present invention provides a liquid crystal polyester resin composition including (1) a liquid crystal polyester, and (2) a fiber-shaped filler having a fiber diameter of 5 to 15 &#x3bc;m and a number average fiber length of 30 to 200 &#x3bc;m, wherein the content of a fiber having a fiber length of more than 200 &#x3bc;m is 10% by mass or less based on 100% by mass of the amount of the fiber-shaped filler.

Liquid crystal polyester resin composition

The present invention provides a thermoplastic resin composition comprising a thermoplastic resin and aggregated particles of fibrous crystals. According to the thermoplastic resin composition, a molded articles which adequately reduce a defect in appearance can be obtained.

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Higashiyamato, Japan

Satoshi Sekimura