Patents by Inventor Jan U. Stoffelsma

Jan U. Stoffelsma 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 for coloring polyvinylchloride
    Patent number: 4495128
    Abstract: Coloring composition for colouring polyvinylchloride comprising at least 40% by weight of coloring pigment and at most 60% by weight of glycerolmonostearate. The composition may be added directly to extruder for extruding polyvinylchloride, the amount of glycerolmonostearate in the moulded article as obtained being restricted to at most 5%.
    Type: Grant
    Filed: June 16, 1980
    Date of Patent: January 22, 1985
    Assignee: Wavin B.V.
    Inventor: Jan U. Stoffelsma
  • Coloring composition for coloring thermoplastic polymers
    Patent number: 4339278
    Abstract: Coloring composition for coloring thermoplastic polymers obtained by solidifying a liquid mixture of coloring pigments and an ester of phtalic acid and an alcohol. The composition contains at least 40% of pigments and at most 60% of an ester of phtalic acid and an alcohol comprising 12 to 16 carbon atoms.
    Type: Grant
    Filed: June 16, 1980
    Date of Patent: July 13, 1982
    Assignee: Wavin B.V.
    Inventor: Jan U. Stoffelsma