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:
May. 24, 1988
Filed:
Jun. 18, 1986
Sheldon M Wecker, Libertyville, IL (US);
Lou Kohl, Palatine, IL (US);
James River-Norwalk, Inc., RiverPark, CT (US);
Abstract
In a method of extruding a plastic product having a foamed core layer and at least one unfoamed skin layer by forcing contiguous flows of a resin through a coextrusion die, one of the flows containing a blowing agent and a nucleating agent for forming the core layer and the second of the flows containing only the blowing agent, for forming the skin layer, the steps of establishing a fluent stream of resin containing the blowing agent, dividing the stream into separate streams which are separately conducted to the coextrusion die to constitute the core-forming and skin-forming flows, respectively, and selectively adding the nucleating agent only to that one of the separate streams which constitutes the core-forming flow. The nucleating agent used can be one which is effectively completely expended when the core layer foams, so that the foamed product is essentially free of active nucleating agent.