Patents by Inventor Tat Y. Choo

Tat Y. Choo 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 of treating spent dryfilm stripping and developing solutions with a chemical mixture
    Patent number: 4999114
    Abstract: A chemical mixture for treating spent dryfilm stripper and developer solutions by mixing the spent solutions with a solution of aluminum sulfate and borax in controlled amounts causing a surface absorption reaction which results in a slurry of a non-sticky, benign precipitate in a supernatant liquid. The supernatant liquid contains the dissolved heavy metals. The non-sticky precipitate does not interfere with the ph measurement which indicates when the reaction is complete, and the benign precipitate can be filtered out for disposal.
    Type: Grant
    Filed: February 16, 1990
    Date of Patent: March 12, 1991
    Assignee: Morton International
    Inventor: Tat Y. Choo
  • Method for treating, spent dryfilm stripping and developing solutions
    Patent number: 4857206
    Abstract: A method of treating spent dryfilm stripper and developer solutions by mixing the spent solutions with a solution of aluminum sulfate and borax in controlled amounts causing a reaction which results in a slurry of a non-sticky, benign precipitate in a supernatant liquid. The supernatant liquid contains the dissolved heavy metals. The non-sticky precipitate does not interfere with the ph measurement which indicates when the reaction is complete, and the benign precipitate can be fillered out for disposal.
    Type: Grant
    Filed: November 2, 1987
    Date of Patent: August 15, 1989
    Assignee: TMC Corp.
    Inventor: Tat Y. Choo