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:
Oct. 10, 2000
Filed:
Oct. 16, 1997
Siebolt Hettinga, Des Moines, IA (US);
Other;
Abstract
A method of molding a plastic with a foamed interior and a dense outer skin of a desired thickness, whereby a blowing agent is mixed with a plastic material and the mixture is injected, under pressure, into a mold cavity of a mold unit. The mixture is allowed to cool along the molding surfaces of the mold cavity for a determined amount of time. The pressure is released and the mold cavity expanded to allow the blowing agent to foam the interior of the plastic article. The molding cavity is then compressed to achieve the desired dimensions for the plastic article, and to give the interior a uniform cellular structure. Control over the timing of the expansion of the mold cavity, the injection temperature, the rate of injection of the mixture, the rate at which the cavity is expanded and compressed, and the timing of the compression of the mold cavity allow a skin of desired thickness to be formed on the plastic article.