A PROCESS FOR PRODUCING POLYVINYL CHLORIDE RESIN

摘要

The present invention provides a process for producing vinyl chloride resin in suspension polymerization of vinyl chloride monomer by the use of a polymerization reactor equipped with a reflux condenser wherein a nonionic surface active agent having a HLB value of 6-14 is added upon initial charging of reactants, polymerization is started in a range of 0.8 to 1.0 of the water/monomer ratio, the polymerization temperature is raised 3 DEG to 10 DEG C. when polymer conversion is not more the 50 weight percent, with water being added in the course of polymerization to not more than make up for the volumetrical contraction resulting from the progress of polymerization so that upon completion of polymerization the water/monomer ratio is controlled in a range of 1.0 to 1.4. The polyvinyl chloride resin obtained by the present process is superior in quality such as high bulk density and little fish eye content with high productivity.