摘要 |
<p>NLJr:TW A process for reducing the residual monomer content in an aqueous vinyl chloride polymer dispersion sensitive to shear and/or temperature stresses, said polymer dispersion containing at least 75% by weight of polymerized vinyl chloride, polymerized in the presence of 0.001% to 1% by weight of emulsifiers, based on the solids content of the dispersion and having an average particle size of from 0.1 to 20 microns, comprising the step of treating said polymer dispersion with steam at an absolute pressure of below atmospheric pressure and a temperature of 50.degree.C to 100.degree.C while evacuating the degassing vessel, for a time sufficient to substantially reduce the residual monomer content, preferably to less than 40 ppm. -A-</p> |