氯化聚氯乙烯后处理工艺优化

Optimization of post treatment process for chlorinated polyvinyl chloride

目前国内外工业化生产氯化聚氯乙烯(CPVC)树脂主要采用水相悬浮法,即,聚氯乙烯树脂在密闭氯化釜中在引发剂作用下与氯气反应生成CPVC,CPVC料浆经脱酸、洗涤、干燥工艺得到CPVC树脂。对氯化后的CPVC料浆后处理工艺进行了优化:1)CPVC料浆脱酸时加入还原剂亚硫酸钠,添加质量分数8%~12%;2)脱酸后的料浆采用蒸馏水洗涤,洗涤时添加乙二胺四乙酸(EDTA),添加质量分数0.05%~0.20%;3)洗涤后进入气流床干燥时添加柠檬酸,添加质量分数8%~11%。结果表明,采用这三种方式优化后,CPVC树脂的热稳定性能和氯含量都得到了提高。

The industrial production of chlorinated polyvinyl chloride（CPVC）resin is mainly prepared by aqueous suspension method at present,namely the PVC resin under the action of the initiator reacts with chlorine to generate CPVC in the closed chloride kettle,then CPVC resin is obtained by deacidification,washing and drying process of the CPVC slurry.The subsequent process was optimized for CPVC slurry obtained by chlorination：1）reducing agent sodium sulfite was added to CPVC slurry while deacidification,adding mass concentration of 8-12 wt%;2）the CPVC slurry after deacidification was washed with distilled water and EDTA was added,adding concentration of 0.05-0.25 wt%;3）the citric acid was added to the CPVC slurry when the slurry was transported to the pneumatic dryer,adding concentration of 8-12 wt%.The results showed that the thermal stability and chloride content of CPVC resin were improved after the subsequent process was optimized by the above three methods