Patents by Inventor Alex Cheung

Alex Cheung 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).

  • Method to produce cyclic esters
    Patent number: 5319107
    Abstract: Disclosed is a method for producing cyclic esters by the conversion of hydroxy carboxylic acids and their derivatives to their respective cyclic esters. Such cyclic esters, including lactide or glycolide, are particularly useful for producing polymers which can be used to make biodegradable materials, such as biodegradable packaging material. Various methods of cyclic ester production are disclosed, including liquid phase and vapor phase reactions. Also disclosed are various methods for recovering cyclic esters from product-containing streams.
    Type: Grant
    Filed: March 19, 1992
    Date of Patent: June 7, 1994
    Assignee: BioPak Technology, Ltd.
    Inventors: Herman P. Benecke, Alex Cheung, George E. Cremeans, Melville E. D. Hillman, Edward S. Lipinsky, Richard A. Markle, Richard G. Sinclair