Polymerization of vinylpyrrolidone
US5306795A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 31, 1991 |
| Grant date | Apr 26, 1994 |
| Priority date | — |
| Expiry date | Jan 31, 2011 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F26/10
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
What is provided herein is a process for making homopolymers of polyvinylpyrrolidone polymer in the form of fine powders at a polymer solids level of at least about 17%, preferably 30% or more, and in a yield of at least about 95%, which comprises precharging a reactor with a predetermined amount of a solvent selected from a C.sub.3 -C.sub.20 alkane, preferably heptane, or a C.sub.3 -C.sub.20 cycloalkane, preferably cyclohexane, and a free radical polymerization initiator, and feeding vinylpyrrolidone monomer into the precharged reactor at a selected rate, preferably about 0.1 to 1.8 g vinylpyrrolidone/min/1000 g of solvent, and most preferably, about 1 g/min/1000 g of cyclohexane and 0.5 g/min/1000 g of heptane, which rates preclude build-up of monomer during the polymerization, and for a feed period which provides the desired level of polymer solids in the reaction product, preferably at least about 200 minutes. The polymer product may be isolated from the reaction mixture by filtration and drying, or by direct drying.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.