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:
Sep. 03, 1985
Filed:
Apr. 05, 1983
Teijin Limited, Osaka, JP;
Abstract
A process for producing an aromatic polyamide film, which comprises drawing an undrawn aromatic polyamide film biaxially at a draw ratio of at least 1.5 in a solvent mixture consisting of (a) 5% to 75% by weight of a good solvent of the aromatic polyamide and (b) 25% to 95% by weight of a non-solvent of the aromatic polyamide, and heat treating the drawn film, which contains at least 1% by weight, based on the weight of the film, of a good solvent of said aromatic polyamide, at a temperature of not lower than 150.degree. C. An m-phenyleneisophthalamide polymer film having extremely excellent dimensional stability under moist conditions, which film has a density d of from 1.35 to 1.41 g/cm.sup.3 and principal refractive indices n.sub..alpha., n.sub..beta. and n.sub..gamma. (n.sub..alpha. >n.sub..beta. >n.sub..gamma.) for D-line of a wavelength of 589 nm satisfying the following formula: ##EQU1##