The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 06, 1983
Filed:
Apr. 30, 1980
Shin-Etsu Chemical Co., Ltd., Tokyo, JP;
Abstract
The invention provides a novel and improved method for the preparation of a cellular foamed body of a vinyl chloride-based resin having a very fine and uniform cellular structure with high productivity in a continuous process. According to the inventive method, a vinyl chloride-based resin is admixed with a nucleating agent and a foam conditioning resin which is a specified acrylic resin or a styrene-based resin into a resin composition and the resin composition is first heated under pressure to be converted into an at least partly gelled mass, into which a volatilizable foaming agent which is an organic solvent having a boiling point not exceeding 90.degree. C. is injected under pressure so as that the resin composition is uniformly impregnated with the foaming agent. The foaming agent-impregnated and completely gelled resin composition is then brought under a reduced pressure to be expanded into foams with simultaneous cooling. The above process is most conveniently practiced by use of an extruder machine in which the volatilizable foaming agent is continuously injected into the cylinder where the heated and gelled resin composition is running.