| 摘要 |
PURPOSE: Metallocene catalysts are provided to produce polyethylene with narrow molecular weight distribution and homogenous composition distribution in a high yield. Also, the catalyst can be activated enough with a small amount of methylaluminoxane (cocatalyst), and can be used for solution polymerization process at a high temperature. CONSTITUTION: The metallocene is represented by formula 1, or formula 2, wherein core metal is a transition metal selected from the group consisting Ti, Zr and Hf in the oxidation state of +3; (C5H4-xRx) is a cyclopentadienyl; R is a C1-C10 hydrocarbon radical; x is an integer of 1-4; B is a bridging group selected from the group consisting (CH3)2Si, CH2CH2 and (CH3)2SiCH2; R' is a radical selected from the group consisting C1-C20 alkyl, cyclic hydrocarbon and aromatic hydrocarbon radical; L is a secondary amide denoted by NR1R2 (R1 and R2,sidentical or different, are a C1-C10 hydrocarbon radical. In the presence of the metallocene catalyst and MAO, ethylene can be polymerized, or ethylene and alpha-olefin can be copolymerized by various polymerizations such as slurry polymerization, gas phase polymerization, or solution polymerization.
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