Patents by Inventor Hirohito Kawama

Hirohito Kawama 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).

  • Publication number: 20060074219
    Abstract: A dehydration step is conducted by heating a mixture containing an organic amide solvent and a sulfur source including an alkali metal hydrosulfide, and a part of an overall charged amount of an alkali metal hydroxide as needed. The mixture remaining within the system after the dehydration step is mixed with a dihalo-aromatic compound, the resultant mixture is heated to conduct a polymerization reaction, and the alkali metal hydroxide is added to the mixture for polymerization reaction continuously or in portions to control the pH of the mixture for polymerization reaction within a range of from 7 to 12.5 from the beginning to the end of the polymerization reaction. The poly(arylene sulfide) according to the present invention has a nitrogen content of at most 800 ppm.
    Type: Application
    Filed: January 21, 2004
    Publication date: April 6, 2006
    Inventors: Hirohito Kawama, Mitsuhiro Matsuzaki, Michihisa Miyahara, Koichi Suzuki, Hiroyuki Sato
  • Publication number: 20050228095
    Abstract: The invention provides a polyarylene sulfide resin composition which can be molded with remarkably reduced trouble of mold-deposit and is improved in thermal stability. The composition contains (A) 100 parts by weight of a polyarylene sulfide resin having a nitrogen element content of 0.55 g or less per 1 kg of the resin and (B) 5-400 parts by weight of an inorganic filler.
    Type: Application
    Filed: March 29, 2005
    Publication date: October 13, 2005
    Applicants: Polyplastic Co., Ltd.,, Kureha Chemical Industry Company, Limited
    Inventors: Katsuhei Onishi, Hirohito Kawama, Kouichi Suzuki, Hiroyuki Sato