Patents by Inventor Craig C. Lewis

Craig C. Lewis 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).

  • Patent number: 5500328
    Abstract: A process is described for recovering cellulose triacetate from scrap photographic film, using aqueous solutions free of organic solvents, by the steps of:a) reducing the film to segments of handlable size;b) oxidizing the film with an oxidizing agent comprising an alkali metal permanganate and a strong acid;c) oxidizing the product of step b) with an alkali metal hypochlorite to remove stain from iron compound and yellow dye;d) bleaching the product of step c) with an alkali metal metabisulfite in an acidic environment; ande) recovering cellulose triacetate.The recovered cellulose triacetate prepared in accordance with this invention has essentially the same spectral absorption at 400 nm as virgin cellulose triacetate and can be used to prepare photographic film base of acceptable color purity.
    Type: Grant
    Filed: January 12, 1995
    Date of Patent: March 19, 1996
    Assignee: Eastman Kodak Company
    Inventors: Robert G. Surash, Craig C. Lewis