This invention is for a metallocene compound which can be used in a catalyst system to produce hemiisotactic polymer. The compound is a bridged metallocene compound having dissimilar cyclopentadienyl groups and no bi-lateral symmetry. One example of the compound is isopropylidene(3-methylcyclopentadienyl-1-fluorenyl) zirconium dichloride. The catalyst of this invention can be converted to an ionic metallocene catalyst by an ionizing agent, such as methylaluminoxane. The polymer produced with this catalyst is characterized by having an isotactic structure effecting only every other asymmetric carbon atom. In the case of polypropylene, every other methyl group is on the same side of the principal polymer chain as represented by a Fisher projection. The remaining methyl groups can be either on the same side or on the opposite side of the principal polymer chain. The polymer produced with the catalyst of this invention can be used as a plasticizer.
这项发明是一种可以用于催化系统中生产半同形聚合物的
金属茂化合物。该化合物是一种桥式
金属茂化合物,具有不同的
环戊二烯基团和没有双侧对称性。该化合物的一个例子是异丙基(3-
甲基环戊二烯基-1-
芴基)
锆二
氯化物。这项发明的催化剂可以通过离子化剂(例如甲基铝氧烷)转化为离子型
金属茂催化剂。使用该催化剂生产的聚合物的特点是具有同形结构,仅影响每个不对称碳原子的另一面。在聚
丙烯的情况下,每隔一个甲基基团在主聚合物链的同侧,由Fisher投影表示。其余的甲基基团可以在主聚合物链的同侧或异侧。使用该发明的催化剂生产的聚合物可用作
增塑剂。