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:
Apr. 04, 1989
Filed:
Aug. 26, 1987
Hideo Katoh, Kanagawa, JP;
Hisashi Hamano, Sagamihara, JP;
Kinji Hasegawa, Yokohama, JP;
Yoshihiro Noumi, Sagamihara, JP;
Teijin Limited, Osaka, JP;
Abstract
A biaxially oriented polyester film formed from an intimate mixture comprising (1) an aromatic polyester, and (2) 0.01 to 4% by weight, based on the aromatic polyester, of spherical fine particles of silica having (a) an average particle diameter of 0.05 to 4 .mu.m, (b) a particle diameter ratio, defined by the ratio of maximum diameter of minimum diameter, of from 1.0 to 1.2, and (c) a relative standard deviation (.sigma.) of particle size, of up to 0.5. A biaxially oriented polyester film formed from an intimate mixture comprising (1) an aromatic polyester, (2) 0.005 to 3% by weight, based on the aromatic polyester, of spherical fine particles of silica having the same properties as the above-mentioned (a), (b) and (c), and (3) 0.005 to 3% by weight, based on the aromatic polyester, of inert fine particles having an average particle diameter of 0.01 to 3 .mu.m and not exceeding the average particle diameter of the spherical fine particles of silica. The biaxially oriented films are useful for a magnetic recording medium.