Polymerization process using a mixed catalyst system
    23.
    发明申请
    Polymerization process using a mixed catalyst system 审中-公开
    使用混合催化剂体系的聚合方法

    公开(公告)号:US20100190936A1

    公开(公告)日:2010-07-29

    申请号:US12661849

    申请日:2010-03-25

    IPC分类号: C08F4/78 B01J31/12

    摘要: Polyethylene is made by (co)polymerizing ethylene in a gas-phase reactor using a mixed catalyst system comprising a chromium catalyst supported on silica and a Group 4 transition metal catalyst, separately supported on silica. The Group 4 transition metal catalyst is defined by the formula shown, wherein M is a Group 4 metal, PI is a phosphinimide or ketimide ligand (shown), L is a monoanionic ligand which is a cyclopentadienyl or a bulky heteroatom type ligand, m is 1 or 2, n is 0 or 1, and p is an integer. The mixed catalyst system gives access to polyethylene having a broad or bimodal molecular weight distribution. In the copolymerization of ethylene, reversed or partially reversed comonomer distribution is achieved: the supported Group 4 component provides polymer segments having higher molecular weight and also higher comonomer incorporation than polymer segments produced at the supported chromium sites.

    摘要翻译: 聚乙烯通过使用包含负载在二氧化硅上的铬催化剂和分别负载在二氧化硅上的第4族过渡金属催化剂的混合催化剂体系在气相反应器中(共)聚合乙烯制成。 第4族过渡金属催化剂由所示的式所定义,其中M为第4族金属,PI为膦酰亚胺或酮酰亚胺配体(显示),L为单阴离子配位体,其为环戊二烯基或大体积杂原子型配体,m为 1或2,n为0或1,p为整数。 混合催化剂体系可以获得具有宽或双峰分子量分布的聚乙烯。 在乙烯的共聚中,实现了反向或部分反向的共聚单体分布:所支持的第4族组分提供了聚合物链段,其具有比在载体的铬位点处产生的聚合物链段更高的分子量和更高的共聚单体掺入。