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. 27, 1999
Filed:
Dec. 29, 1997
Sumitomo Chemical CO., LTD., Osaka, JP;
Abstract
The present invention provides a method for producing a methyl methacrylate polymer, wherein monomers containing methyl methacrylate as a main component are bulk-polymerized or solution-polymerized in the presence of a polymerization initiator and mercaptan compound as a chain transfer agent to form a liquid polymer composition containing unreacted monomers and then a volatile content is separated from the liquid polymer composition, the method comprising the steps of: distilling the volatile content to recover unreacted monomers, (1) subjecting the residue to a contact treatment with hydrazine compound or (2) subjecting the residue to an azeotropic distillation with water to remove impurities, distilling the resultant to recover the mercaptan compound and reusing the mercaptan compound as the chain transfer agent of raw materials.