| 摘要 |
<p>Vinyl chloride, opt. with a comonomer is polymerised in microsuspension in the presence of a nucleating agent in the form of a dispersion of particles of a vinyl polymer previously prepd. by polymerisation in micro-suspension contg. at least one organically soluble initiator without introduction of free initiator into the polymerisation being carried out in the presence of one or more further nucleating agents in the form of dispersions of Vi polymers particles, the size of which is different from that of the 1st nucleating agent. PVC plastisols of improved properties are obtd. if the polymer comprises individual particles of at least two separate populations of different particle sizes. The achievement of such a compsn. previously a delicate and difficult process partic. at high solids contents is readily accomplished by means of the invention enabling microsuspensions to be prepd. of concn. appreciably above 45 wt.% low viscosity and completely reproducible particle size distribution.</p> |
