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.

Date of Patent:
Aug. 23, 1994

Filed:

Apr. 24, 1992
Applicant:
Inventors:

Gary C Welsh, Midland, MI (US);

Eric K Lee, Waterloo, CA;

Brian D Dalke, Midland, MI (US);

Assignee:

The Dow Chemical Company, Midland, MI (US);

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
C08J / ;
U.S. Cl.
CPC ...
521 82 ; 521 97 ; 521 98 ; 521130 ; 521146 ; 521908 ;
Abstract

An improved polystyrene foam having less corrugation is disclosed which uses carbon dioxide as the blowing agent and 1-30 weight percent endothermic agent, such as water, with the weight based on the total carbon dioxide blowing agent and endothermic agent weight. This combination of carbon dioxide and endothermic agent decreases the corrugation of the thermoplastic foam, while just slightly increasing density, when the process parameters, including throughput, are equivalent to using only carbon dioxide. The process an also allow an increased foaming temperature and greater process throughput of an equivalent density thermoplastic foam at approximately equivalent corrugation levels when compared to the use of only using only carbon dioxide.


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