Patents by Inventor Roy W. J. Pearce

Roy W. J. Pearce 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: 5795940
    Abstract: Colour concentrate pellets for pigmenting polyvinyl chloride are substantially all of diameter 0.1 to 3 mm and comprise pigment dispersed in a carrier comprising ethylene-vinyl acetate polymer which is ethylene-vinyl acetate copolymer and/or alloy thereof with polyethylene, the polymer having a vinyl acetate content of 13-28% by weight and a melt flow index (as measured by the method of ASTM D1238 using a 2.16 kg weight at 190.degree. C.) of 3.5-150 g/10 minutes, the pellets comprising at least 30% by weight of the pigment and at least 10% by weight of the polymer.
    Type: Grant
    Filed: September 23, 1996
    Date of Patent: August 18, 1998
    Assignee: Cookson Matthey Ceramics PLC
    Inventors: Roy W. J. Pearce, Nigel B. Smith
  • Patent number: 4285994
    Abstract: This invetion relates to novel pigement compositions and processes of making the same. The pigments of the present invention are free-flowing and a process for their production comprises a process for the production of a free-flowing pigment composition comprising tumbling together a finely divided wax composition as herein defined with a powdered pigment for a time sufficient for substantialy all of the pigment to be coated onto or to be absorbed by the wax. Specifically, a pigment in accordance with the invention comprises a free-flowing nucleated pigment composition comprising a substantially spherical particulate spray-chilled wax composition (as herein defined) having coated thereon and partially absorbed thereinto a pigment in powdered form, the said pigment being present to the extent of 50% by weight or more.
    Type: Grant
    Filed: July 3, 1980
    Date of Patent: August 25, 1981
    Assignee: Johnson, Matthey & Co., Limited
    Inventors: Roy W. J. Pearce, John Carbert, John P. K. MacDonald