Patents by Inventor Hajime Sadatoshi

Hajime Sadatoshi 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).

  • Process for producing propylene-ethylene block copolymers
    Patent number: 4254237
    Abstract: A process for producing propylene-ethylene block copolymers by a three-step polymerization technique using a stereoregular catalyst, characterized in that the first-step polymerization is carried out by supplying propylene alone or a propylene/ethylene mixture so that the ethylene/propylene reaction ratio is 6/94 or less, thereby polymerizing 60 to 95% by weight of the total polymerization amount, the second-step polymerization is carried out by supplying a propylene/ethylene mixture so that the ethylene/propylene reaction ratio is 15/85 to 79/21, thereby polymerizing 1 to 20% by weight of the total polymerization amount, and the third-step polymerization is carried out by supplying a propylene/ethylene mixture so that the ethylene/propylene reaction ratio is 50/50 to 89/11, thereby polymerizing 4 to 35% by weight of the total polymerization amount, with the ethylene/propylene reaction ratio in the third step made larger than that in the second step.
    Type: Grant
    Filed: April 16, 1979
    Date of Patent: March 3, 1981
    Assignee: Sumitomo Chemical Company, Limited
    Inventors: Akinobu Shiga, Masahiro Kakugo, Hajime Sadatoshi, Kazuki Wakamatsu, Hiroshi Yoshioka