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:
Apr. 10, 1979
Filed:
Apr. 29, 1976
Howard P Cordts, Grafton, WI (US);
Eugene J Grandlic, Sheboygan, WI (US);
Freeman Chemical Corporation, Port Washington, WI (US);
Abstract
Lightweight glass fiber reinforced plastic articles are produced in matched dies by combining fibrous reinforcing materials, such as glass fibers, with a foamable unsaturated polyester resin composition. The matched dies are closed and compressed so that the resin composition fills the mold cavity and wets the fibrous reinforcing material. Thereafter the matched dies are separated to increase the volume of the mold cavity by at least 50 percent greater than the closed volume. The matched dies are retained in this relationship until the unsaturated polyester resin composition has cured and expanded to fill the mold cavity. The resulting product has a density less than 67 percent of the density of a corresponding reinforced plastic article fabricated from the same composition (unsaturated polyester resin, fillers and reinforcement), which is not foamed. The unsaturated polyester resin composition preferably includes 0.5 to 3 percent by weight (based on the weight of unsaturated polyester resin) of an azo blowing agent to accomplish resin cure and foaming. The resulting products exhibit energy absorption characteristics when compared with other fiber reinforced plastic products, compared on a strength-to-weight basis.