Process for the preparation of vinylpyrrolidone/vinyl acetate copolymers
US5319041A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 26, 1993 |
| Grant date | Jun 7, 1994 |
| Priority date | — |
| Expiry date | Mar 26, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F226/10
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
This invention relates to an improved process for producing a clear solution of vinylpyrrolidone (VP) and vinyl acetate (VA) monomers which comprises, in an anhydrous system, (a) reacting a C.sub.2 to C.sub.3 alcoholic solution containing said VA monomer and between about 60 and about 80 wt. % portion of total VP monomer in the presence of between about 0.05 and about 0.3 wt. % of a free radical initiator selected from the group consisting of tertamylperoxy pivalate and 2,2-azobis(2-methylbutyronitrile) or a mixture thereof for a period of from about 5 to about 10 hours, at a temperature between about 60.degree. and about 110.degree. C.; (b) gradually adding the remaining VP monomer in C.sub.2 to C.sub.3 alcohol solution at reaction temperature after the addition of the VA monomer is complete; (c) raising the temperature of the resulting reaction mixture to between about 110.degree. and about 150.degree. C.; (d) continuing the polymerization reaction at said higher temperature in the presence of from about 0.11 to about 0.6 wt. %, based on total monomers, of 2,5-dimethyl-2,5-bis(tert-butylperoxy) hexane and (e) cooling the resulting reaction mixture and recovering a homogeneous VP/…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.