The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 03, 1979
Filed:
Jul. 25, 1978
Jorgen Petersen, Sundsvall, SE;
Kemanobel AB, Stockholm, SE;
Abstract
The invention relates to a process for reducing the monomer content in expandable thermoplastic beads which are produced by polymerizing an ethylenically unsaturated monomer or a mixture of such monomers in aqueous suspension in the presence of a blowing agent. The residual monomers in both the beads and the process water are reduced by treatment of the slurry of beads and water obtained after polymerization in a vessel at a temperature above 65.degree. C. in the presence of at least one water-soluble initiator. In order to avoid the expansion of the beads during the course of monomer reduction the vessel is kept completely filled with a liquid, preferably water, during the temperature treatment.