Patents Assigned to Colloid Research Institute
  • Electrorheological fluid compositions
    Patent number: 5294426
    Abstract: Electrorheological fluid compositions of this invention are dispersions in an electrically insulating medium of 10 to 50% by volume of spherical silica particles prepared by hydrolyzing a silicon alkoxide of the general formula Si(OR).sub.4 in which R is an alkyl group in the presence of an alkali catalyst and drying at or below 500.degree. C., show excellent fluidity in the absence of an applied voltage, vary reversibly to the state of high viscosity or even to the state of gel on application of a voltage, and have good storage stability.
    Type: Grant
    Filed: July 22, 1991
    Date of Patent: March 15, 1994
    Assignee: Colloid Research Institute
    Inventors: Masahiro Sekine, Yasufumi Otsubo, Shingo Katayama
  • Process for preparing zirconia sols and/or zirconia forms
    Patent number: 5238625
    Abstract: Zirconia sols are prepared by hydrolyzing zirconium alkoxides by aqueous hydrogen peroxide in the presence of an acid, evaporating the hydrolysates to dryness, and redispersing the dried hydrolysates in an organic solvent and the sols can be used for the preparation of zirconia forms in a desired shape satisfactorily on a commercial scale with removal of as much residual carbon as possible and without foaming in the gelation and molding steps.
    Type: Grant
    Filed: August 6, 1991
    Date of Patent: August 24, 1993
    Assignee: Colloid Research Institute
    Inventors: Chihiro Sakurai, Masahiko Okuyama
  • Process for preparing oxynitride ceramic fibers
    Patent number: 5114887
    Abstract: The process of this invention for preparing oxynitride ceramic fibers comprises spinning a viscous sol obtained by the hydrolysis of a feed mainly consisting of metal alkoxides, steam-treating the gel fibers, and firing the steam-treated gel fibers in a stream of ammonia and is commercially useful for the production of oxynitride fibers with excellent hardness, strength, modulus of elasticity, heat resistance, and corrosion resistance.
    Type: Grant
    Filed: April 19, 1991
    Date of Patent: May 19, 1992
    Assignee: Colloid Research Institute
    Inventors: Masahiro Sekine, Shingo Katayama