Patents by Inventor Wha Chen

Wha Chen 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).

  • One-pot process for the preparation of 5-sulfonyl-substituted benzotriazoles UV absorbers
    Patent number: 6040455
    Abstract: 5-Sulfonyl substituted benzotriazole UV absorbers are prepared from the corresponding 5-chlorobenzotriazole in a two step, but one-pot process where the second step involves the oxidation of the non-isolated 5-thio substituted benzotriazole using sodium tungstate, hydrogen peroxide and formic acid. The 5-sulfonyl substituted benzotriazoles exhibit enhanced absorption in the near-visible range (over 350 nm) thus providing effective protection to substrates in this critical area of the spectrum.
    Type: Grant
    Filed: January 21, 1999
    Date of Patent: March 21, 2000
    Assignee: Ciba Specialty Chemicals Corporation
    Inventors: Mervin G. Wood, William Wiggins, Catherine Blake, Albert Carpenter, Wha Chen
  • Alkanolamine esters of acyclic phosphites in polyolefin compositions
    Patent number: 5521237
    Abstract: Selected alkanolamine esters of acyclic phosphites are particularly effective as process stabilizers for polyolefins providing for melt flow stabilization and resistance to discoloration during said processing.
    Type: Grant
    Filed: June 6, 1994
    Date of Patent: May 28, 1996
    Assignee: Ciba-Geigy Corporation
    Inventors: Raymond Seltzer, Wha Chen, Roswell E. King, III, Paul Odorisio, Rita Pitteloud, Sai P. Shum