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:
Dec. 31, 1991
Filed:
Sep. 25, 1990
Applicant:
Inventor:
Gary L Hendren, Richmond, VA (US);
Assignee:
E. I. Du Pont de Nemours and Company, Wilmington, DE (US);
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
D21H / ;
U.S. Cl.
CPC ...
162123 ; 162146 ; 1621573 ; 162206 ;
Abstract
High temperature resistant pressboard having a density of 0.70 to 0.90 g/cc, a calculated void volume of 31 to 49, percent by volume of said pressboard and a smoothness of 80 to 250 microinches MD range and 90 to 260 microinches is disclosed. The pressboard is prepared by wet laying an aqueous dispersion of polyaramid fibrids and floc to form a waterleaf building up layers to form a wet lap which is dried and then pressed at 270.degree. C. to 520.degree. C. rising a press with a predetermined minimum opening to form the desired smooth low density pressboard.