高效催化剂对聚丙烯树脂分子量、分子量分布及纺丝性能的影响

燕山石化公司化纤地毯厂在采用高效催化剂前、后生产的新、老3702聚丙烯树脂(熔体流动指数MFI均为12—15)纺丝时,纺丝温度和纤维性能发生了显著变化。研究结果表明,这种差别主要是由于它们的分子量分布不同所引起的。新3702由于分子量分布较窄,与老3702聚丙烯树脂相比,即使在相同的MFI条件下,粘均分子量和零切变粘度也是较低的,因而纺丝温度也低。在工业生产中表明,除测定MFI外还应测定聚丙烯熔体在230℃下的零切变速率粘度,这对指导生产,能提供可靠依据。采用高效催化剂生产MFI为7—11的新3602牌号聚丙烯在燕山石化公司化纤地毯厂试纺中,废丝率下降了7%以上,成丝质量得到了提高。

EFFECTS OF HIGH-EFFICIENCE CATALYST ON THE MW,MWD AND SPINNING PROPERTY OF PP RESIN

PP resins with the same melt flow index (MFI) obtained from different catalysts have obvious differences in the spinning temperature and mechanical properties of finished fibres. The reason for this phenomenen is the difference in molecular weight distribution (MWD) of these PP resins. The PP resin obtained from high-efficience catalyst shows more narrow MWD than that from ordinary catalyst. Evon though their melt flow indexes are similar, the former shows lower viscosity average MW, zero shear rate viscosity of PP melt and lower spinning temperature than the latter. Spinning experiments in industry scale shows that it is necessary to measure the zero shear rate viscosity of PP melt at 230℃ in spite of measuring MFI.