Synthesis Of High Bulk Density PVC Resin

In order to prepare polyvinyl chloride (PVC) for rigid pipe, a formation model for particles of PVC with high bulk density in the suspension polymerization was proposed. The particles could be well-controlled by choosing optimized suspending agents and agitation. On the basis of the investigation of interfacial tension and colloid-protecting ability of single and mixture suspending system, the recipe of the suspending system for high bulk density PVC was presented. Under the optimized recipe, high bulk density PVC was prepared in the reactor with capacity of 5L, 10L, 375L and 7m3, respectively. The optimized recipe will be industrially used in the reactor with capacity of 127m .During the formation of PVC particles with high bulk density, the agglomeration of grains and primary particles was well controlled. To prepare high bulk density PVC a mixture suspending system including PVA with high degree of hydrolysis, suspending agent with good colloid-protecting ability, and oil-dissolved suspending agent \va,-; proposed.The interfacial tension and colloid-protecting ability of single and mixture suspending system were studied. The interfacial tension and colloid-protecting ability of mixture suspending systems were the summation of each component's. To prepare high bulk density PVC, the mixture suspending systems, A1/B1/A10 and A2/B1/A10, were proposed. The primary suspending agents, A1/B1 and A2/B1, had good colloid-protecting ability, and will be helpful to obtain high bulk density of PVC. The co-suspending agent, A10. had good oil-dissolution, and will be helpful to get good porosity of particles.The effects of single and mixture suspending systems on bulk density, porosity and mean particle diameter of PVC were studied in the reactor with capacity of 5L and 10L,respectively. If die ratio of primary suspending agent to co-suspending agent was 14/1, and the values of A1/B1 and A2/B1 were 1.5/1 or 1/1, the PVC with bulk density of 0.51 g/ml and porosity of 25 gDOP/gPVC could be produced.To prepare high bulk PVC, other methods such as adjusting agitation, adding suspending agents in the process of polymerization and adding anti-static agent were used.With the mixture suspending system A2/B1/A10, PVC with bulk density of 0.57 g/ml and porosity of 19 gDOP/gPVC could be produced in the reactor with capacity of 375L and 7m3, respectively. The optimized recipe of the mixture suspending system and agitation were proposed for industrial production.