Patents Represented by Attorney Walter F. Tewell

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  • Lignosulfonic graft copolymer as a cement dispersant
    Patent number: 4977227
    Abstract: This invention provides a cement dispersant of a lignosulfonic acid graft copolymer, obtained by a redox free radical reaction of lignosulfonic acid or its salts with one or more acrylic or vinylic monomers containing functional groups, in an aqueous solution in the presence of a radical initiator, e.g, redox catalyst. The lignosulfonic acid graft copolymer has a molecular weight distribution of from 5.times.10.sup.2 to 5.times.10.sup.6.
    Type: Grant
    Filed: November 28, 1988
    Date of Patent: December 11, 1990
    Assignee: Sandoz Ltd.
    Inventors: Shin'ichi Negami, Hiroshi Nomachi, Toru Nemoto, Yoshio Tanaka, Akira Ohta