Patents by Inventor Hiroshi Nakaoka

Hiroshi Nakaoka 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 purifying tetrahydrofurans used as starting material for polyether polyols
    Patent number: 6201137
    Abstract: Tetrahydrofurans suitable for use as starting materials in the synthesis of polyether polyols without causing coloration in the product polyether polyols can be obtained by contacting crude tetrahydrofurans with a mineral acid or a strongly acidic cation-exchange resin, followed by isolation through a simple distillation and/or rectification to obtain purified tetrahydrofurans.
    Type: Grant
    Filed: August 11, 1999
    Date of Patent: March 13, 2001
    Assignee: Hodogaya Chemical Co., Ltd.
    Inventors: Hiroshi Nakaoka, Toshiro Kubota
  • Process for producing polyether, and process for recycling and reusing herteropolyacid
    Patent number: 5756604
    Abstract: An industrially advantageous process described below has been established wherein tetrahydrofuran and a cyclic ether copolymerizable therewith are copolymerized by the use of a very small amount of a commercially available heteropolyacid as it is untreated, the heteropolyacid of the catalyst is recovered, recycled and reused in a simple way, and a high quality polyether substantially free from catalyst contaminants is obtained.
    Type: Grant
    Filed: August 28, 1996
    Date of Patent: May 26, 1998
    Assignee: Hodogaya Chemical Co., Ltd.
    Inventors: Hiroshi Nakaoka, Hideyuki Ishii, Masami Suganami