申请人:California Institute of Technology
公开号:US06469188B1
公开(公告)日:2002-10-22
The invention provides metallocene catalyst systems for the controlled polymerization of alkenes to a wide variety of polyolefins and olefin coplymers. Catalyst systems are provided that specifically produce isotactic, syndiotactic and steroblock polyolefins. The type of polymer produced can be controlled by varying the catalyst system, specifically by varying the ligand substituents. Such catalyst systems are particularly useful for the polymerization of polypropylene to give elastomeric polypropylenes. The invention also provides novel elastomeric polypropylene polymers characterized by dyad (m) tacticities of about 55% to about 65%, pentad (mmmm) tacticities of about 25% to about 35%, molecular weights (Mw)in the range of about 50,000 to about 2,000,000, and have mmrm+rrmr peak is less than about 5%.
该发明提供了用于控制烯烃聚合制备各种聚烯烃和烯烃共聚物的茂金属催化剂系统。提供了可特异产生同构、异构和立体垒积聚烯烃的催化剂系统。通过变化催化剂系统,特别是通过变化配体取代基,可以控制所产生的聚合物类型。这种催化剂系统特别适用于聚丙烯的聚合,以产生弹性聚丙烯。该发明还提供了新型弹性聚丙烯聚合物,其二聚体(m)的立构度约为55%至65%,五聚体(mmmm)的立构度约为25%至35%,分子量(Mw)在约50,000至2,000,000的范围内,并且mmrm+rrmr峰值小于约5%。