Ethylene copolymers with a novel composition distribution and processes for making the same
AssigneeFormosa Plastics Corporation
InventorsHonglan Lu, Guangxue Xu
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Abstract
A Ziegler-Natta catalyzed ethylene copolymer having a novel composition distribution in which comonomers are incorporated into the high molecular weight polymer molecules and distributed evenly among the entire polyethylene chains, and a method for making the same are provided. The resins having a novel composition distribution have controlled molecular weight distribution which is narrower than conventional ZN-ethylene copolymers but broader than single-site catalyzed ethylene copolymers. The resins having a novel composition distribution exhibit a superior tear strength and impact strength.
Claims21
A Ziegler-Natta catalyzed ethylene alpha-olefin copolymer, further comprising:
- a density of between 0.900 g/cc and 0.930 g/cc;
- a melt index ratio (I21/I2) of between 20 and 35 dg/min;
- a melt index (I2) of between 0.1 and 10 dg/min;
- and
- a polydispersity index (Mw/Mn) of between 3.0 and 5.0;
- wherein the Temperature Raising Elution Fractionation (TREF) fraction distribution of the copolymer has at least 15 wt % of TREF fractions below an elution temperature of 35° C.;
- and
- wherein the copolymer is produced by reacting ethylene and an alpha-olefin comonomer in the presence of a titanium-based Ziegler-Natta catalyst in a gas-phase process at reaction temperatures in the range of about 50° C. to about 100° C.
Dependencies are inferred from the claim text.