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. 11, 1990
Filed:
Feb. 05, 1990
Mitsubishi Chemical Industries Limited, Tokyo, JP;
Diafoil Company, Limited, Tokyo, JP;
Abstract
A heat-resistant film or sheet produced by melt extruding polyether ketone having an intrinsic viscosity of at least 0.4 dl/g, which is obtained by heat treating an unstretched film or sheet which comprises (i) heat-treating to crystallization being not more than 60%, or (ii) uni- or biaxially stretching under specific conditions to an extent in which a stress at 5% elongation in the stretched direction is at least 13 kg/mm.sup.2 ; an initial elastic modulus in the stretched direction is at least 600 kg/mm.sup.2 ; and thermal shrinkages in a lengthwise direction and its vertical direction are not more than 4%. The film or sheet of the present invention is excellent in such properties as heat resistance, mechanical strength and the like, and is suitable for use as a substrate for magnetic recording or electric insulation.