高熔体流动速率PP产品质量控制

Quality control of polypropylene with high melt flow rate

生产高熔体流动速率(MFR)聚丙烯的过程中,丙烯质量、MFR、等规指数、灰分及造粒工艺条件是影响产品质量的主要因素。根据生产经验,提出了丙烯及精制合格丙烯的质量指标,分析了影响产品MFR、等规指数和灰分的控制措施:主要通过控制H2和引发剂加入量调节MFR;当n(Al)/n(Si)和n(Si)/n(Ti)分别控制在5.0和5.5左右时,产品等规指数可较好地满足质量要求;结合设备状况和工艺参数的控制,提出了保证造粒机切粒效果的方法。

Quality of propylene, melt flow rate （MFR）, isotacticity, ash content and pelletizing conditions were considered as main factors influencing product quality in the production of polyethylene with high MFR. The quality indexes of the raw propylene feedstock and the qualified propylene after refining were put forward according to the experiences accumulated in the production. The effective measures for controlling MFR, isotacticity and ash content of the product were analyzed. The product＇s MFR was generally adjusted by appropriately regulating the adding amount of the initiator and hydrogen. The product＇s isotacticity could well meet the quality requirements when the molar ratio of Al/Si and Si/Ti were set at about 5.0 and 5.5, respectively. The method to ensure the pelletizing performance of the pelletizer was proposed in the light of equipment status combined with control of process parameters.