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. 14, 1994
Filed:
Oct. 15, 1991
Mirza A Baig, Des Plaines, IL (US);
United States Gypsum Company, Chicago, IL (US);
Abstract
An improved composite material is produced by mixing gypsum and host particles of a stronger substance, such as wood fibers, in a dilute slurry; heating the slurry, under pressure, to convert the gypsum to calcium sulfate alpha hemihydrate; and substantially dewatering the hot slurry before rehydrating the hemihydrate back to gypsum. The resulting material is a homogoneous mass comprising gypsum crystals physically interlocked with the discrete host particles. According to a further aspect of the invention, an improved wallboard, having fire resistance, dimensional stability and excellent strength properties, is produced by compressing the composite mass before hydrating it to a final set.