Purification of vinyl lactam polymers
US5239053A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 14, 1992 |
| Grant date | Aug 24, 1993 |
| Priority date | — |
| Expiry date | Feb 14, 2012 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F6/006
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.