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:
Mar. 20, 1979
Filed:
Feb. 27, 1978
Louis A Cutter, Pittsburgh, PA (US);
Robert E Nunn, Marion, OH (US);
United States Steel Corporation, Pittsburgh, PA (US);
Abstract
Styrene is copolymerized with maleic anhydride by mixing maleic anhydride with styrene under mass polymerization conditions in a ratio of styrene to maleic anhydride of at least 5:1, continuing to add maleic anhydride throughout a mass polymerization stage until about 25% to about 40% of the styrene monomer is reacted to produce a reaction mass in which the polymerized maleic anhydride is about 1% to about 10% of the total reaction mass. The polymerization is then completed in a pH-adjusted free-radical initiated suspension stage, which generates homopolymer of styrene. During the suspension stage about 10% to about 20% of the bound maleic anhydride is hydrolyzed. The acid component of the bound maleic acid may be converted back to the anhydride through the use of a vented extruder.