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. 09, 1990
Filed:
Mar. 20, 1989
Kenji Takasa, Yokosuka, JP;
Satoshi Iijima, Kamakura, JP;
Asahi Kasei Kogyo Kabushiki Kaisha, Osaka, JP;
Abstract
This present invention provides a biaxially oriented film of a polyoxymethylene polymer having the main part of each of the main chains thereof substantially composed of repeating units of the oxymethylene group, --CH.sub.2 --O--, which biaxially oriented polyoxymethylene polymer film is characterized by the fact that the crystallinity thereof measured by the density method is in the range of 75 to 95% and the degree of crystal orientation measured by the X-ray diffraction method in the two directions of end and edge are each in the range of 80 to 98%. This film possesses a high modulus of elasticity, outstanding dimensional stability, and low equilibrium water absorption ratio and, therefore, it is particularly suitable as a base film of a magnetic recording medium. This film is produced by accurately controlling the orientation conditions and other processing conditions.