Patents by Inventor Atsuo Kawakami

Atsuo Kawakami 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).

  • Continous polymerization method of laurolactam and apparatus therefor
    Patent number: 5362448
    Abstract: A continuous polymerization method for laurolactam which has three stages. A prepolymerization process include steps of preliminarily heating laurolactam with 1 to 10% weight of water added, thereafter continuously feeding and passing the laurolactam from the upper part of the lower part of the longitudinal-type polymerization reaction zone, arranging a temperature decreasing gradient of 10.degree. C. or more than the upper part to the lower part directions at a polymerization temperature of 250.degree. and 300.degree. C. in the polymerization zone, and polymerizing the laurolactam under vapor pressure up to a conversion rate of 99.5% or more. A intermediate process has a step of releasing pressure from the prepolymerization product from the prepolymerization process for conversion into an intermediate product at atmospheric pressure.
    Type: Grant
    Filed: October 12, 1993
    Date of Patent: November 8, 1994
    Assignee: Ube Industries, Ltd.
    Inventors: Atsuo Kawakami, Toshiro Shimada, Tatsuo Tsumiyama, Hisaya Yamaguchi
  • Continuous hydrolytic polymerization of laurolactam
    Patent number: 5283315
    Abstract: A continuous polymerization method for laurolactam which has three stages. A prepolymerization process include steps of preliminarily heating laurolactam with 1 to 10% weight of water added, thereafter continuously feeding and passing the laurolactam from the upper part of the lower part of the longitudinal-type polymerization reaction zone, arranging a temperature decreasing gradient of 10.degree. C. or more than the upper part to the lower part directions at a polymerization temperature of 250.degree. and 300.degree. C. in the polymerization zone, and polymerizing the laurolactam under vapor pressure up to a conversion rate of 99.5% or more. A intermediate process has a step of releasing pressure from the prepolymerization product from the prepolymerization process for conversion into an intermediate product at atmospheric pressure.
    Type: Grant
    Filed: August 14, 1992
    Date of Patent: February 1, 1994
    Assignee: UBE Industries, Ltd.
    Inventors: Atsuo Kawakami, Toshiro Shimada, Tatsuo Tsumiyama, Hisaya Yamaguchi