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:
Jan. 18, 1994
Filed:
Sep. 03, 1992
Tomoyuki Kotani, Machida, JP;
Daifoil Hoechst Company Limited, Tokyo, JP;
Abstract
A laminated polyester film for a magnetic recording medium which has a first polyester layer (A) containing inorganic particles (a) having a Moh's hardness of at least 8 and a specific average particle size and inactive particles (b) having a Moh's hardness of less than 8 and a specific average particle size larger than that of the particle (a) and a second polyester layer (B) containing inactive particles (c) having a Moh's hardness of less than 8 and a specific average particle size, wherein a content of the particles (a) is from 0.25 to 5% by weight based on the weight of the polyester in the layer (A) and less than 0.15% by weight of the whole weight of the polyester in the layers (A) and (B), the contents of the particles (b) and (c) are each 0.05 to 2.0% by weight of the polyester in the layers (A) and (B), respectively, and exposed surfaces of the layers (A) and (B) have coefficients of friction and surface roughness (Ra) which satisfy the specific conditions.