摘要
通过转矩流变仪测试了临界脱模用量,研究了聚乙烯蜡A-C 617A和硬脂酸钙(Ca St2)作为PVC润滑剂的金属润滑特性,结果表明:两者均为有效的金属润滑剂,单独使用时,后者明显比前者更有效,协同使用时,具有明显的协同效应。协同作用的金属润滑作用机理为:单独使用时,两者均可铺展润湿金属表面,形成润滑层,阻碍PVC熔体与金属表面直接接触,Ca St2以极性头向内而非极性尾向外的方式润湿金属表面;合并使用时,A-C 617A蜡分子可插入Ca St2润滑层的非极性尾-非极性尾界面和Ca St2润滑层极性尾-PVC熔体界面形成滑移层,而Ca St2能溶解于AC 617A,并吸附于A-C 617A-金属界面和A-C 617A-PVC熔体界面,提高了稳定性,润滑层阻碍了PVC熔体与金属表面的直接接触润滑效果得到明显增强。
The metal lubrication of polyethylene wax A-C 617 A and calcium stearate( Ca St2) as polyvinyl chloride(PVC) lubricants were investigated by testing the critical use levels for metal release using a torque rheometer. The results indicated that these two lubricants were both the effective metal lubricants,although the former was significantly less effective than the latter; there was a significant synergistic effect when they were combined. The metal lubrication mechanisms of A-C617 A and Ca St2 could be deduced as follows. When they were used alone,both could spread over and wet the metal surface to form a lubricating layer to prevent the PVC melt and metal surface from contacting directly,and Ca St2 wetted the metal surface with the polar heads inward and non-polar tails outward. When they were combined,on the one hand,the molecules of A-C 617 A could be inserted into the non-polar tail interfaces of Ca St2 lubricating layers and the interfaces between Ca St2 lubricating layer's non-polar tail and PVC melt to form slip layers,on the other hand,Ca St2 could be dissolved in A-C617 A and adsorbed on A-C 617 A-metal interfaces and A-C 617 A-PVC melt interfaces to make the stability improved.As a result,the effect of the lubricant layers on preventing the PVC melt and metal surface from contacting directly was enhanced.
引文
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