Patent ID: 9228030
Filing Date: 2016-01-05
CPC Classification: C08F

Claim Text:
1. A method for the preparation of a copolymer of ethylene and an alpha-olefin suitable for use in rotomolding applications, said copolymer having a (a) density>0.930 g/cm (b) melt index (g/10 min)>4, (c) molecular weight distribution (MWD)>3.0, (d) full notch creep test (FNCT)>250 hours, and (e) Composition Distribution Branch Index (CDBI) in the range 55 to 75%, said method comprising copolymerising ethylene and an alpha-olefin in the presence of a metallocene catalyst system comprising a monocyclopentadienyl metallocene complex having the formula: wherein: R′ each occurrence is independently selected from hydrogen, hydrocarbyl, silyl, germyl, halo, cyano, and combinations thereof, said R′ having up to 20 nonhydrogen atoms, and optionally, two R′ groups (where R′ is not hydrogen, halo or cyano) together form a divalent derivative thereof connected to adjacent positions of the cyclopentadienyl ring to form a fused ring structure; X is neutral η Y is —O—, —S—, —NR*—, —PR*—; M is titanium or zirconium in the +2 formal oxidation state; Z* is SiR* R* each occurrence is independently hydrogen, or a member selected from hydrocarbyl, silyl, halogenated alkyl, halogenated aryl, and combinations thereof, said R* having up to 10 non-hydrogen atoms, and optionally, two R* groups from Z* (where R* is not hydrogen), or an R* group from Z* and an R* group from Y form a ring system.