Method for polymerizing vinyl chloride with controlled water addition
US5235012A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 21, 1992 |
| Grant date | Aug 10, 1993 |
| Priority date | — |
| Expiry date | Apr 21, 2012 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC08F14/06
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
An improved method for the suspension polymerization is proposed which gives a PVC resin product having an increased plasticizer absorptivity and greatly decreased content of fish eyes. The invention can be achieved by additionally adding a limited volume of water into the polymerization mixture under proceeding of the polymerization reaction within a specified period of 30 to 70% monomer conversion and at such a controlled rate as not to unduly decrease the pressure inside of the reactor. The improvements are particularly remarkable when the dispersing agent added to the polymerization mixture is a ternary combination of (A) a water-soluble partially saponified polyvinyl alcohol of a high degree of polymerization and a high degree of saponification, (B) a hydroxypropyl methyl cellulose having specified degrees of substitution with methoxy and hydroxypropoxy groups and specified viscosity characteristics and (C) a monomer-soluble partially saponified polyvinyl alcohol of a low degree of polymerization and a low degree of saponification, each in a specified amount.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.