Sekisui Kaseihin Kogyo Kabushiki Kaisha

Sekisui Plastics Co., Ltd.

Toshiro Kobayashi

Motoshige Hayashi

Tsuneo Doi

Hideki Kobayashi

A method for manufacturing thermoplastic resin expandable granules comprising the steps of: injecting a blowing agent under pressure into a thermoplastic resin which is melted in an extruder; extruding the melted resin containing the blowing agent as an extrudate from a plurality of small holes in a die attached to a distal end of the extruder directly into a coolant liquid, and directly cutting the extrudate by high-speed rotary blades; and cooling and solidifying the extrudate by contacting with the coolant liquid, and thereby obtaining the expandable granules wherein the melted resin containing the blowing agent passing through land parts of the small holes of the die is extruded such that a shearing speed is 12,000 to 35,000 sec, and an apparent melt viscosity of the resin is 100 to 700 poise.

Influence of each of the parameters on the foamed product strength

A method of producing thermoplastic resin foams is disclosed. The method comprising extruding an expandable resin through a plurality of holes bored in a die in the inside of a frame fitted to the extrusion end surface of the die in an adjacent relation therewith and fusing together the thus-extruded materials while they are expanded and still softened, wherein the inner surfaces of the frame are inclined at an angle of inclination ranging between 5.degree. and 30.degree., so that the cross-sectional area of the frame is increased toward the outer end thereof, and the extruded materials are fused together while kept in contact with the inner surfaces of the frame.

Method for production of thermoplastic resin foams

A process for producing an expanded article of a thermoplastic resin by extruding and expanding a foamable resin using an extruder equipped, on a resin channel in a die, with a nozzle having a number of apertures, which comprises flowing a resin mixture stream through an expansion zone while maintaining the resin mixture at a temperature above the melting point thereof, dividing the resin mixture stream into a plurality of separate streams, exiting these streams from the extrusion zone directly into a confined zone, thereby forming a plurality of soft expanded resin strands corresponding in number to the number of strands, bringing the strands into surface contact with each other to fuse and bond them together to form a bonded expanded resin mass while simultaneously removing gases generated in the course of extrusion and expansion, passing the bonded mass into an unconfined zone to permit the mass to further expand while still in a softened condition, passing the further expanded mass into a confined receiving zone of a smaller cross-sectional area than the further expanded mass, and cooling the mass to form an expanded article.

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Nara, Japan

Toshiro Kobayashi