聚丙烯挤出发泡中“熔体破裂”现象分析  

Melt Fracture and Its Effects on Foam Quality in Extrusion Foaming of PP

作　　者：徐志娟[1] 何继敏[1] 朱复华[1] 薛平[1] 

机构地区：[1]北京化工大学机电工程学院,北京100029

出　　处：《塑料工业》2005年第1期30-33,共4页China Plastics Industry

基　　金：北京化工大学青年基金 (QN0 2 15 )

摘　　要：研究了聚丙烯挤出发泡过程中“熔体破裂”现象及其对发泡体质量的影响。对比采用不同形状的机头口模的发泡试样 ,发现不能建立足够高压的机头中 ,PP/气体形成的单相溶液在离开机头口模之前发生相分离 ,提前发泡 ,使表面发生“熔体破裂” ,发泡体的质量差 ;不同螺杆转速和机头温度对发泡体质量影响不同 :对应一定温度 ,存在获取高质量泡沫的最佳螺杆转速范围 (对Φ2mm喷丝机头 ,转速为 3 0～ 40r/min) ;相同转速下 ,温度过低 (低于 15 0℃ )或过高 (高于 185℃ )都会使挤出物表面产生“熔体破裂”现象 。The melt fracture during the extrusion foaming process of PP and its effects on foams qualities were studied.Compared with the foaming samples extruded by different dies,it was found that the single phase of PP/gases solution separated before the mixture left the die and advanced foaming happened because the die could not establish high enough pressure.Therefore,the melt fracture happened and the qualities of the foams were poor.Different screw speeds and die temperatures had different effects on the qualities of foams.There was an optimal range of screw speed(Φ2 mm filament die,screw speed from 30 to 40 rpm) at given temperature;over high (higher than 190 ℃) or over low (lower than 135 ℃) die temperature would lead to the melt fracture of extruder at same screw speed,and the qualities of foams would be correspondingly poor.

关 键 词：聚丙烯 发泡 熔体破裂 机头形状 

分 类 号：TQ320.663[化学工程—合成树脂塑料工业]