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:
Jan. 04, 2000

Filed:

Nov. 25, 1997
Applicant:
Inventors:

Yuichiro Murayama, Odawara, JP;

Katsuhiko Meguro, Odawara, JP;

Masaki Satake, Fujinomiya, JP;

Hiroshi Hashimoto, Odawara, JP;

Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
G11B / ;
U.S. Cl.
CPC ...
428216 ; 428336 ; 4284259 ; 4286 / ; 4286 / ; 4286 / ; 428900 ;
Abstract

The present invention provides a magnetic recording medium having good electromagnetic transfer characteristics and high running durability, and it comprises a lower layer and a magnetic layer, said lower layer having at least one of magnetic powder or non-magnetic inorganic powder and a binder (A) dispersed therein and being placed on a non-magnetic support member, at least one layer of said magnetic layers having ferromagnetic powder and a binder (B) dispersed therein and being deposited on said lower layer, whereby said magnetic recording medium comprises polyurethane resins (1) and (2), said polyurethane resin (1) is contained as said binder (B) and comprises a short-chain diol having a cyclic structure and weight average molecular weight of 200 to 500 in an amount of 15 to 50 weight %, a polyol having an ether group of 1 to 6 mmol/g and weight average molecular weight of 500 to 5000 in an amount of 10 to 50 weight % in polyurethane, and an organic diisocyanate, and said polyurethane resin (2) is contained as said binder (A) and comprises a short-chain diol having cyclic structure and weight average molecular weight of 200 to 500 in an amount of 0 to 15 weight %, a polyol having an ether group of 6 to 14 mmol/g and weight average molecular weight of 500 to 5000 in an amount of 50 to 90 weight %, and an organic diisocyanate.


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