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:
May. 08, 1979
Filed:
Aug. 25, 1977
Buren R Ree, Stillwater, MN (US);
Louis A Errede, North Oaks, MN (US);
Gary B Jefson, St. Paul, MN (US);
Bruce A Langager, New Brighton, MN (US);
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
Abstract
A polytetrafluoroethylene composite sheet having a tensile strength of at least one megapascal and comprising particulate material distributed in a matrix of interentangled polytetrafluoroethylene fibrils. The composite sheet is prepared by blending the particulate material with polytetrafluoroethylene aqueous dispersion in the presence of sufficient lubricant water to exceed the absorptive capacity of the solids yet maintain a putty-like consistency, subjecting the putty-like mass to intensive mixing at a temperature between 50.degree. C. and 100.degree. C. to cause initial fibrillation of the polytetrafluoroethylene particles, biaxially calendering the putty-like mass to cause additional fibrillation of the polytetrafluoroethylene particles while maintaining the same water content and drying the resultant sheet.