热稳定剂的耐热性、加工性及其对PVC制品透明性的影响

The heat resistance and processability of heat stabilizers and their influences on the transparency of PVC products

分析了评价热稳定剂热稳定性的方法,同时评价热稳定剂的长期耐热性及初期着色性,不宜只用刚果红变色法或烘箱热变色方法;论述了固体复合热稳定剂的加工性能,提出了PVC加工性的评价标准;指出了评价加工性能不清楚甚而不确切的概念,如:熔融因子、塑化因子、塑化值、熔融比值;论述了一些固体复合热稳定剂在扭矩流变曲线图中出现的平台状塑化峰对PVC加工性的影响;详细论述了热稳定剂及其他助剂对塑料制品透明性的影响。

Methods of evaluating the heat stability of heat stabilizers were discussed. It was indicated that using Congo red method or oven heat discoloration method was not suitable to evaluate the long term heat stability and the initial coloration at the same time. The processing property of solid composite heat stabilizer was discussed. Standards of evaluating the processing property were proposed. Some undefined or inexactly concepts for evaluating the processing properties, such as melt factor, plasticizing factor, plasticizing value and melt ratio, were indicated. Influences of some solid composite stabilizers with flatform peak in torque rheological curve on the processing properties of PVC were discussed. Influences of heat stabilizers and other additives on the transparency of PVC plastics were analyzed in detail.