摘要 |
<p>The present invention relates to the manufacture of suspension grade PVC and other vinyl chloride resins of superior overall quality, especially in that they possess both high bulk densities and excellent porosities as shown by their fast absorption rates for hot liquid plasticizers. The key feature of the suspension polymerization process involved is the use of a particular combination of two types of suspending agents throughout the process, namely a polyvinyl alcohol resin with a hydrolysis level of about 68 to about 78 percent together with a hydroxypropyl cellulose ether with a molar substitution of between about 2 and about 4.</p> |