| 摘要 |
<p>1419145 Polymerizing chloroprene MONSANTO CO 29 May 1973 [30 May 1972] 25554/73 Heading C3P Chloroprene is polymerized in aqueous dispersion to obtain a product of narrow particle size distribution by (1) forming a polymerization medium comprising water, a redox system containing sulphate and sulphite ions and a metal activator and optionally an emulsifier, (2) allowing these to interact, (3) adding monomer, (4) introducing additional sulphate ions together with emulsifier where none was added at (1) or optionally with further emulsifier and (5) maintaining polymerization conditions to polymerize at least a major proportion of monomer. The particle sizes fall in the range 0À15-2 microns. In one example two dispersions containing different sized particles, one being 0-2 micron, the other 0À6 micron, are mixed. The redox sulphate radicals may be obtained by oxidation of sulphite radicals using a peroxide or as in the examples by using a persulphate/bisulphite initiator. Sodium lauryl sulphate is the preferred emulsifier. In one example acrylonitrile is copolymerized with the chloroprene.</p> |
