Patents by Inventor Kayoko Yokota

Kayoko Yokota 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 lactic acid polymers and a process for the direct production of shaped articles from lactic acid polymers
    Patent number: 5574129
    Abstract: A process for producing polylactic acid includes the steps of polycondensing lactic acid to a lactic acid prepolymer having a weight-average molecular weight of 10,000-50,000 in a batch-type polymerization reactor, and polycondensing the lactic acid prepolymer to lactic acid polymer having a weight-average molecular weight of at least 100,000 by means of a screw-type extruder.
    Type: Grant
    Filed: May 5, 1995
    Date of Patent: November 12, 1996
    Assignee: The Japan Steel Works, Ltd.
    Inventors: Rika Miyoshi, Tadamoto Sakai, Noriaki Hashimoto, Yukihiro Sumihiro, Kayoko Yokota, Kunihiko Koyanagi