线性低密度聚乙烯薄膜晶点问题分析及改进措施  

Analysis and improvement measures of the crystal point problem of thin film of linear low-density polyethylene

作　　者：吴希 雷佳伟 余宗蔚 邓起垚 朱昊 陈云静 WU Xi;LEI Jia-wei;YU Zong-wei;DENG Qi-yao;ZHU Hao;CHEN Yun-jing(SINOPEC-SK(Wuhan)Petrochemical Co Ltd,Wuhan 430000,China)

机构地区：[1]中韩(武汉)石油化工有限公司,湖北武汉430000

出　　处：《石化技术与应用》2023年第2期126-129,共4页Petrochemical Technology & Application

摘　　要：针对中韩(武汉)石油化工有限公司线性低密度聚乙烯(牌号为EGF-35 B)薄膜料吹膜出现的晶点问题,采用差示扫描量热仪、偏光显微镜以及红外光谱分析仪等测试手段,从外观、熔流比、表观黏度、结晶微观结构、熔点、结晶分子结构等方面综合分析了晶点形成的原因,并采取了改进措施。结果表明:EGF-35 B树脂中存在交联高分子聚合物或杂质,导致其熔点和结晶度较低,在吹膜过程中不能均匀熔融分散,先于周围的聚合物形成膜,从而形成晶点;通过采取控制聚合温度、反应器床层料位、脱气仓反吹系统、粉料输送系统,以及挤压机系统的维护,并且制定合理的牌号切换顺序等措施,可减少晶点问题。In view of the crystal point problem of the blown film of LLDPE EGF-35 B of SINOPEC-SK(Wuhan)Petrochemical Co Ltd,differential scanning calorimeter,polarizing microscope and infrared spectrum analyzer were used to analyze the reasons for the formation of crystal points comprehensively in terms of the appearance,melt flow ratio,apparent viscosity,crystal microstructure,melting point and crystal molecular structure.Besides,improvement measures were proposed.The results showed that there were cross-linked polymers or impurities in the polyethylene resin EGF-35 B,which caused its melting point and crystallinity to be lower.It could not be melted and dispersed uniformly during the film blowing process,and the film was formed before the surrounding polymer,thereby forming a crystal point.Measures such as controlling the polymerization temperature,the material level of the reactor bed,the degassing bin backflushing system,the powder conveying system and the maintenance of the extruder system,and formulating a reasonable order of brand switching were suggested to reduce the crystal point problem.

关 键 词：聚乙烯 薄膜 晶点 交联高分子聚合物 结晶度 改进措施 

分 类 号：TQ325.12[化学工程—合成树脂塑料工业]