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:
Aug. 24, 1993
Filed:
Feb. 14, 1992
Susan Y Tseng, Staten Island, NY (US);
William L Mandella, Boonton, NJ (US);
Terry E Smith, Morristown, NJ (US);
Robert B Login, Oakland, NJ (US);
Paul D Taylor, West Milford, NJ (US);
ISP Investments Inc., Wilmington, DE (US);
Abstract
Vinylpyrrolidone and vinylcaprolactam residual monomers are removed from their respective crosslinked and non-crosslinked, vinyl lactam homopolymers, vinyl lactam copolymers and vinyl lactam terpolymers containing substantially contaminating amounts of residual vinylpyrrolidone or vinylcaprolactam monomer by a process which comprises (1) adjusting the pH of the vinyl lactam polymer slurry containing from about 1 to about 30 wt. % solids or a solution of the vinyl lactam polymer to a pH of less than 5 with an acid selected from the group of sulfuric, phosphoric, carbonic, formic and acetic acids and mixtures thereof; (2) reacting the acid with the residual vinyl lactam monomer at a temperature of from about 50.degree. to about 150.degree. C. for a period of from about 0.5 to about 10 hours until the residual monomer is reduced to less than 5 ppm and (3) drying said solids to a substantially pure vinyl lactam polymeric product in a free-flowing particulate state.