Patents by Inventor Seiji Watatani

Seiji Watatani has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 4561034
    Abstract: A magnetic recording medium such as a magnetic tape, which comprises a base film, a magnetic layer having an elastic modulus at 1% elongation of not less than 1,200 kg/mm.sup.2 totally in both longitudinal and width directions which is higher than that of the base film, said magnetic layer being formed on one surface of the base film, and a backcoat layer having an elastic modulus at 1% elongation of not less than 1,200 kg/mm.sup.2 totally in both longitudinal and width directions which is higher than that of the base film, said backcoat layer being formed on another surface of the base film, said magnetic recording medium having a total thickness of not more than 17.mu., said magnetic recording medium having excellent mechanical strength and being used without buckle and injury during usage even in a thin thickness.
    Type: Grant
    Filed: November 23, 1982
    Date of Patent: December 24, 1985
    Assignee: Hitachi Maxell, Ltd.
    Inventors: Naoto Akahane, Yoshitake Yamaguchi, Takeshi Matsuura, Seiji Watatani
  • Patent number: 4363850
    Abstract: A magnetic recording medium which comprises a base material and a magnetic layer provided thereon. The magnetic layer comprises magnetic particles, a cellulose resin and a polyurethane resin as the binders and .alpha.-Fe.sub.2 O.sub.3 particles, whereby the dispersibility of the magnetic particles in the magnetic layer is enhanced without deterioration of the durability of the magnetic layer.
    Type: Grant
    Filed: October 24, 1980
    Date of Patent: December 14, 1982
    Assignee: Hitachi Maxell, Ltd.
    Inventors: Masaaki Yasui, Takeshi Matsuura, Seiji Watatani
  • Patent number: 4322474
    Abstract: A magnetic recording medium, prevented from blooming of the lubricants therein even after used at a high temperature under a high humidity for a long period of time and excellent in abrasion resistance and durability, comprising an elastic base sheet and a magnetic layer containing magnetic powders and a binder, characterized in that the magnetic layer further contains (A) at least one of esters of saturated aliphatic acids having 18 carbon atoms with aliphatic alcohols having 3 to 6 carbon atoms, (B) at least one of saturated aliphatic acids having 14 to 18 carbon atoms and (C) at least one of zinc salts of saturated aliphatic acids having 14 to 18 carbon atoms, the content of the component (A) being from 0.5 to 2.
    Type: Grant
    Filed: March 3, 1980
    Date of Patent: March 30, 1982
    Assignee: Hitachi Maxell, Ltd.
    Inventors: Takeshi Matsuura, Seiji Watatani