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:
Oct. 05, 1982
Filed:
May. 14, 1980
Asahi Kasei Kogyo Kabushiki Kaisha, Osaka, JP;
Abstract
Disclosed is a biaxially drawn polyhexamethylene adipamide film having a relative viscosity of at least 3.2 as measured at 25.degree. C. in aqueous 96% H.sub.2 SO.sub.4, a degree of crystallinity of from 35% to 45%, a birefringence (.DELTA.n) of not more than 0.006, as determined at any point in its entire area, and an initial modulus of elasticity in tension of at least 230 kg/mm.sup.2 as determined in ay direction across substantially its entire area. The film may be produced by a process wherein molten polyhexamethylene adipamide is extruded through a circular die gap and the tubular extrudate is brought in sliding contact with the outer periphery of an inside mandrel, thereby to be cooled, which process is characterized in that polyhexamethylene adipamide having a relative viscosity of from 3.3 to 5.0, as measured at 25.degree. C. in aqueous 96% H.sub.2 SO.sub.4, is used; the tubular extrudate formed therefrom is cooled at a cooling rate (X.degree. C./sec.) satisfying the following formula with respect to the relative viscosity of the polymer used,