Lubricant In Overcoat Layer Patents (Class 428/841.3)
  • Patent number: 8623529
    Abstract: An object of the present invention is to provide a perpendicular magnetic recording medium including a suitable lubricating layer with sufficient durability, moisture resistance, and contamination resistance and also maintaining an R/W characteristic. In a typical structure of the present invention, a method of manufacturing a perpendicular magnetic recording medium 100 including a magnetic recording layer 122, a medium protective layer 126, and a lubricating layer 128 in this order on a base 110 includes: a CF bond density measuring step of measuring a CF bond density of a lubricant; and a lubricating layer forming step of forming a lubricating layer with the lubricant when the measured CF bond density is 2.0×1022 to 2.7×1022 atoms/cm3.
    Type: Grant
    Filed: March 24, 2009
    Date of Patent: January 7, 2014
    Assignee: WD Media (Singapore) Pte. Ltd.
    Inventor: Kouta Suzuki
  • Patent number: 8563148
    Abstract: Subject: A process for producing a magnetic recording medium, having a magnetic recording layer and a protective layer on a substrate which is a non-magnetic support, wherein the medium is able to greatly inhibit migration of a lubricant from the protective layer to the surface of the metal pressing plate having a mirrored finish in a hot pressing step during production of the magnetic recording medium, while maintaining satisfactory scratch resistance, suitable adhesion with the magnetic recording layer and the protective layer, and excellent read and write properties of the magnetic recording medium.
    Type: Grant
    Filed: January 20, 2009
    Date of Patent: October 22, 2013
    Assignee: DIC Corporation
    Inventors: Satoshi Hayakawa, Daisuke Yano, Yoshikazu Yamazaki
  • Patent number: 7440233
    Abstract: The present invention provides a magnetic recording medium with a reduced tendency for a free layer to become thicker near an outer periphery than near an inner periphery of a recording zone as well as provides an information reproducing apparatus which is equipped with the magnetic recording medium and reproduces information according to the magnetization at various points on the magnetic recording medium. A magnetic layer carries information in an outer zone outside a predetermined inner zone around a through-hole. That part of the free layer which is located in the outer zone is thinner near the outer periphery than near the inner periphery.
    Type: Grant
    Filed: February 14, 2005
    Date of Patent: October 21, 2008
    Assignee: Fujitsu Limitd
    Inventor: Shinichi Takahashi
  • Patent number: 7195828
    Abstract: A magnetic recording medium and method for forming the magnetic recording medium are described. The magnetic recording medium includes a magnetic layer formed on a non-magnetic support, and a lubricant layer over the magnetic layer. The lubricant layer includes a compound selected from hydrocarbyl-substituted cyclopentanes, hydrocarbyl-substituted cyclopentenes, hydrocarbyl-substituted cyclopentadienes, and mixtures or derivatives thereof and, optionally, one or more additives. The lubricant layer also may be used on a magnetic head for reading and writing information on a magnetic recording medium. The magnetic recording medium and the magnetic head may be used to manufacture computer disk drives, compact disk drives, audio equipment, and video equipment.
    Type: Grant
    Filed: October 4, 2001
    Date of Patent: March 27, 2007
    Assignee: Shell Oil Company
    Inventors: Selda Gunsel, Clifford Venier, I-Ching Chiu