Process for producing vinyl chlorine-based polymer via continuous or intermittent addition of dispersing stabilizer
US5376747A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 24, 1993 |
| Grant date | Dec 27, 1994 |
| Priority date | — |
| Expiry date | Sep 24, 2013 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F14/06
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A process for suspension polymerizing vinyl chloride or a monomeric mixture containing the same in an aqueous medium comprising the step of adding a partially saponified polyvinyl alcohol having an average polymerization degree of 600 to 800 and a saponification degree of 65 to 75 mol % to a polymerization system, wherein the partially saponified polyvinyl alcohol is added before start of polymerization, and also after-added continuously or intermittently over the period from the start of polymerization to the time when a polymerization conversion of 10 to 30% is reached. By the suspension polymerization process, it is possible to obtain a vinyl chloride-based polymer having high bulk specific gravity, high gelation rate and a certain level of thermal stability and showing an effectively reduced number of fish eyes when formed into shaped products.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.