US 6,630,256 B2
Magnetic recording medium comprising a non-magnetic layer having inorganic particles of specific size and distributionGeneral
US 6,630,256 B2
Magnetic recording medium comprising a non-magnetic layer having inorganic particles of specific size and distribution
Tech Center:
1700 Chemical and Materials Engineering
Examiner:
H. Thi Le
Art Unit:
1773 Chemical Apparatus, Separation and Purification, Liquid and Gas Contact Apparatus
Inventors:
Masaki Suzuki; Toshihiko Miura; Masatoshi Takahashi; Hiroaki Takano
Assignee:
Priority:
08/03/00
Filed:
07/31/01
Granted:
10/07/03
Expiration:
07/31/21
Abstract
Provided is a magnetic recording medium with a total thickness equal to or less than 8 &mgr;m having good electromagnetic characteristics and good repeat running durability in which the dropping of powder onto the running path and tape edge deformation are prevented and a magnetic recording medium with a total thickness equal to or less than 8 &mgr;m having good electromagnetic characteristics, good repeat running durability, and good dimensional stability. A magnetic recording medium having on one surface of a nonmagnetic support a lower layer comprising an inorganic powder and a binder and an upper magnetic layer comprising a ferromagnetic powder and a binder in that order, and having on the other surface thereof a backcoat layer, wherein: said nonmagnetic support comprises inorganic powder particles with a mean primary particle diameter in a range of from 40 to 200 nm; the number of particles of said inorganic powder in the cross-section of said nonmagnetic support is in a range of from 10 to 200/100 &mgr;m2, said nonmagnetic support exhibits a coercivity in a range of from 159 to 239 kA/m; and the overall thickness is equal to or less than 8 &mgr;m. A magnetic recording medium having on one surface of a nonmagnetic support a lower layer comprising an inorganic powder and a binder and an upper magnetic layer comprising a ferromagnetic powder and a binder in that order, and having on the other surface thereof a backcoat layer, wherein: said nonmagnetic support comprises inorganic powder particles with a mean primary particle diameter in a range of from 10 to 200 nm; the number of particles of said inorganic powder in the cross-section of said nonmagnetic support is in the range of from 10 to 200/100 &mgr;m2, the amount of curl d in the direction of width of said magnetic recording medium is equal to or higher than 0.4 mm and equal to or less than 1.0 mm in the direction of protrusion of the magnetic layer at a width of 6.35 mm; and the overall thickness is equal to or less than 8 &mgr;m.
Cooperative Patent Classification (CPC)
G11G11B5/733G11B