Method for the suspension polymerization of vinyl chloride monomer
USRE32813E · kind E · reissue
Assignee
Inventors
Key dates
| Filing date | Dec 7, 1987 |
| Grant date | Dec 27, 1988 |
| Priority date | — |
| Expiry date | Dec 7, 2007 |
Classification
- Technology area (CPC —)General
Abstract
The invention provides an improvement in the suspension polymerization of vinyl chloride or a monomer mixture mainly composed of vinyl chloride in an aqueous medium containing a nonionic surface active agent and in the presence of a monomer-soluble polymerization initiator, according to which the aqueous polymerization medium is admixed with a crosslinked copolymer having carboxyl group such as a copolymer of acrylic acid and diethyleneglycol bisallyl or bismethallyl ether at a moment when the percentage of the monomer conversion is in the range from 1 to 20% so that a polyvinyl chloride resin product of high quality can be obtained having an outstandingly high bulk density and plasticizer absorptivity but still containing an extremely small number of fish eyes.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.