Chemically Specified Binder Patents (Class 428/839.4)
  • Patent number: 7585576
    Abstract: A magnetic recording medium includes a non-magnetic supporter, a first magnetic layer and a second magnetic layer on which magnetic paints made of different ferromagnetic materials are applied in order of the first magnetic layer and the second magnetic layer on the non-magnetic supporter. Both the first magnetic layer and the second magnetic layer include polyester polyol having an alicyclic framework and a polyurethane resin composed of diisocyanate.
    Type: Grant
    Filed: November 13, 2003
    Date of Patent: September 8, 2009
    Assignee: Sony Corporation
    Inventors: Atsushi Kato, Junji Kagawa, Hiroyuki Murakami, Fumiko Koike
  • Patent number: 7449257
    Abstract: A magnetic recording medium is provided that includes a non-magnetic support, and at least one magnetic layer provided above the non-magnetic support, the magnetic layer having a ferromagnetic powder dispersed in a binder, all or part of the binder being a polyurethane resin obtained by a reaction of a polyol and a polyisocyanate, the polyurethane resin having a glass transition temperature (Tg) of 70° C. to 200° C., and part of the polyol being a diol having at least one epoxy group and two hydroxyl groups per molecule. There is also provided a process for producing the magnetic recording medium, the process including a step of kneading the ferromagnetic powder and the polyurethane resin.
    Type: Grant
    Filed: October 22, 2004
    Date of Patent: November 11, 2008
    Assignee: FUJIFILM Corporation
    Inventors: Masahiko Mori, Hiroshi Hashimoto, Yuichiro Murayama
  • Patent number: 7005203
    Abstract: Provided is a magnetic recording medium that exhibits excellent electromagnetic characteristics especially in recording and reproducing systems using an MR head, as well as has excellent long-term preservation property. The magnetic recording medium comprises a lower layer comprising a nonmagnetic powder or a ferromagnetic powder and a binder and at least one magnetic layer thereover comprising a ferromagnetic powder and a binder on a support.
    Type: Grant
    Filed: September 4, 2003
    Date of Patent: February 28, 2006
    Assignee: Fuji Photo Film Co., Ltd.
    Inventors: Satoshi Matsubaguchi, Yuichiro Murayama