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:
Jun. 15, 1999
Filed:
Jul. 23, 1997
Howard Sims Hammel, Bear, DE (US);
Robert Oliver York, Wilmington, DE (US);
E. I. du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
An improved closed cell polymer foam and foaming agent involving the use of a hydrogen-containing halocarbon blowing agent (e.g., HCFC-22) in combination with an effective amount of a hydrogen bond forming blocking agent (e.g., organic ether, ester or ketone). The presence of the blocking agent is shown to significantly reduce the escape of blowing agent from and entry of air into the foam resulting in low thermal conductivity over a longer period of time and improved thermal insulation value. A closed cell thermoplastic foam such as polyethylene, polypropylene, polystyrene, among others, is disclosed produced by means of an environmentally friendly nonflammable blowing agent substantially free of halogen substituents other than fluorine and comprising HFC-134 (1,1,2,2-tetrafluoroethane).