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:
Aug. 10, 1993
Filed:
Feb. 13, 1992
Minoru Takezawa, Ohta, JP;
Shigeo Yatsu, Tatebayashi, JP;
Fumihisa Endo, Ohta, JP;
Akihiro Morita, Ohragun, JP;
Yuji Kishi, Ohta, JP;
Sanyo Electric Co., Ltd., Osaka, JP;
Abstract
According to the present invention, there is provided a rigid foamed polyurethane and a process for the manufacture of the polyurethane wherein the polyurethane is made up substantially of closed cells which contain at least a foaming agent designated by HCFC-22 and CO.sub.2 gas therein. The foamed polyurethane can be obtained by using HCFC-22 or a blend of the HCFC-22 with HCFC-142b as foaming agent which has a short life in the atmosphere because of having hydrogen atoms in their molecules. Thus, according to the present invention, it is possible to avoid the use of conventional foaming agents which are suspected of being substances eating a hole in the atmospher's layer of ozone and consequently linking to global warming. The rigid foamed polyurethanes of the present invention, which contain a foaming agent designated by HCFC-22 having a boiling point of -40.8.degree. C. in their closed cells, can retain their good thermal insulating properties over a temperature of from about -30.degree. to -40.degree. C., and can be used for most applications in the extremely cold conditions. Further, when employing a HCFC-22 blend containing a specific amount of HCFC-142b as foaming agent, there is provided a rigid foamed polyurethane having a less change in thermal insulating properties on standing while retaining good flame resistance of the rigid foam.