Patents by Inventor Johannes A. M. Willemsen

Johannes A. M. Willemsen 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 shortstopping an emulsion polymerization
    Patent number: 5177164
    Abstract: A process for shortstopping a free radical polymerization of a conjugated diene and optionally a vinyl-substituted aromatic in an aqueous emulsion, using a hydroperoxide as initiator and a redox activator, comprising a divalent transition metal, a reducing agent and optionally being carried out in the presence of a modifier, and being performed by using as sole shortstopping agent an alkali metal polysulphide. This process results in the production of polymeric products which are free of carcinogenic nitrosamines.
    Type: Grant
    Filed: June 28, 1991
    Date of Patent: January 5, 1993
    Assignee: Shell Oil Company
    Inventors: Sijtske M. De Vries, Johannes A. M. Willemsen