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.

Date of Patent:
Mar. 27, 1990

Filed:

Sep. 29, 1988
Applicant:
Inventors:

Hiroshi Ogawa, Kanagawa, JP;

Shinji Saito, Kanagawa, JP;

Makoto Yoshimura, Kanagawa, JP;

Shinichi Funabashi, Kanagawa, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H01F / ;
U.S. Cl.
CPC ...
427130 ; 427131 ; 427132 ; 428694 ; 428900 ;
Abstract

A method for manufacturing a magnetic recording medium comprising the steps of: (1) providing a lower layer comprising a ferromagnetic powder dispersed in a binder on a non-magnetic support and (2) providing an upper layer comprising a ferromagnetic powder dispersed in a binder on the lower layer, wherein a solvent used in a magnetic coating composition for the lower layer contains at least 30 wt % of an organic solvent having an evaporation rate index of less than 50; a solvent used in a magnetic coating composition for the upper layer contains from 0 to 40 wt % of an organic solvent having an evaporation rate index of less than 50; the content of an organic solvent having an evaporation rate index of less than 50 in the coating composition for the upper layer is smaller than that in the coating composition for the lower layer; the magnetic coating composition for the upper layer is coated while the lower layer is not dried; and when the lower and upper layers are dried until the total solvent content of the lower and upper layers is in the range of from 0.05 to 3 wt %, a calendering treatment is carried out.


Find Patent Forward Citations

Loading…