Biphasic polymerization process
US6359102B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 29, 1998 |
| Grant date | Mar 19, 2002 |
| Priority date | — |
| Expiry date | Jun 29, 2018 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08G63/87
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
Improvements are disclosed for biphasic polymerization processes in which an aqueous solution of a first monomer that is hydrolytically unstable below a pH of about six or above a pH of about eight is admixed with a water-immiscible organic solvent and there is added to the admixture a catalyst selected from tertiary amine, quaternary amine and phosphonium catalysts, an acid-forming co-monomer for the first monomer, an acid scavenger, after which the resulting polymer is recovered, wherein the improvement includes providing the aqueous solution at a pH between about si and about eight, and adding to the admixture the acid-forming co-monomer and the acid scavenger at relative rates effective to maintain the pH of the admixture between about six and about eight. The catalyst may be added in a molar ratio to the first monomer effective to provide a predetermined weight-average or number-average molecular weight for the resulting polymer. Biphasic polymerization processes for monomers that are not pH sensitive are also disclosed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.