Patents by Inventor Akiyasu Ishii

Akiyasu Ishii 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).

  • Optical phase plate and production process thereof
    Patent number: 5042924
    Abstract: An optical phase plate is provided in the form of a drawn and oriented film or sheet, having a composition comprising a vinylidene fluoride resin and a methyl methacrylate resin in a mixing ratio of the former to the latter between about 65/35 and about 85/15 by weight, in which the crystal structure of the vinylidene fluoride resin consists mainly of a .beta.-form and the film or the sheet has dimensional stability and a retardation value R within a range from 500 to 650 nm. The optical phase plate is produced by uniformly kneading and melt-extruding the predetermined PVDF/PMMA mixture into a sheet and subjecting the sheet to drawing and then to heat treatment.
    Type: Grant
    Filed: March 8, 1990
    Date of Patent: August 27, 1991
    Assignees: Kureha Chemical Industry Co., Ltd., Fujitsu Limited
    Inventors: Shuji Terasaki, Mitsuru Ohta, Akiyasu Ishii, Yuji Kojima, Akira Tanaka
  • Process for the manufacture of halogen-containing resin particles of larger bulk density comprising mixing particles of the resin with inorganic salts, treated in a mixture in a gaseous phase and separating the inorganic salt from the product
    Patent number: 4391763
    Abstract: This invention relates to a compactingly processing method for the manufacture of spherical particles, having a heavier apparent specific gravity, of halogen-containing ethylene resin. In this method, 100 wt. parts of particles of the resin are mixed with 20-500 wt. parts of one or more of heat-resisting inorganic salts having particle sizes of 0.01-50.mu.. This mixture is subjected to a heat treatment in a gaseous phase at a temperature higher than the melting point of the resin, and then, the once added inorganic salt or salts is/are separated from the heat-treated intermediate products. In this way, the resin particles are subjected to a substantial compacting and size reduction.
    Type: Grant
    Filed: January 12, 1981
    Date of Patent: July 5, 1983
    Assignee: Kureha Kagaku Kogyo Kabushiki Kaisha
    Inventors: Kunihiko Ueno, Akiyasu Ishii, Masazi Hukuda, Kazuyuki Nakayama