Process for making vinyl pyrrolidone/vinyl acetate copolymers having a very low residual vinyl pyrrolidone monomer level within a short production cycle
US6939927B1 · kind B1 · utility
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Key dates
| Filing date | Sep 21, 2004 |
| Grant date | Sep 6, 2005 |
| Priority date | — |
| Expiry date | Sep 21, 2024 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F218/06
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Vinyl pyrrolidone/vinyl acetate copolymers having a very low residual vinyl pyrrolidone monomer level, i.e. <100 ppm, preferably only 50 ppm, are made within an advantageously short production cycle, by post-treating an aqueous solution of the copolymer at an elevated temperature of about 120–150° C., preferably about 130° C., under pressure, in the presence of a high temperature initiator, for a period of about 1–4 hours, preferably 2 hours.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.