Patents by Inventor Wilhelmus G. Duijzings

Wilhelmus G. Duijzings 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).

  • Process for the preparation of copolymers containing low monomer content
    Patent number: 4200593
    Abstract: An improved process for the preparation of copolymers by the polymerization of from about 25 to 85 parts by weight of a styrene and/or .alpha.-methylstyrene monomer together with about 15-75 parts by weight of acrylonitrile and/or methacrylonitrile monomer in an aqueous dispersion in the presence of a compound yielding free radicals is disclosed whereby the quantity of monomer remaining in the copolymer after polymerization is substantially reduced. A compound yielding water-soluble free radicals is added to the aqueous reaction medium, containing copolymer as well as non-converted monomer, in a quantity of between about 0.05 and 2.5 parts per 100 parts by weight of monomer and copolymer present in the reaction medium, at a point of time at which (a) the rate of conversion of monomer to copolymer is less than 15% per hour, (b) the degree of conversion of monomer to copolymer is greater than 75%, and (c) at least 0.
    Type: Grant
    Filed: July 17, 1978
    Date of Patent: April 29, 1980
    Assignee: Stamicarbon, B.V.
    Inventors: Jozef L. M. van der Loos, Wilhelmus G. Duijzings