Dual catalyst system for producing LLDPE copolymers with a narrow molecular weight distribution and improved processability
AssigneeChevron Phillips Chemical Company LP
InventorsMark L. Hlavinka, Chung Ching Tso, Yongwoo Inn, Deloris R. Gagan, Randy S. Muninger
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Abstract
Disclosed herein are ethylene-based polymers generally characterized by a Mw ranging from 70,000 to 200,000 g/mol, a ratio of Mz/Mw ranging from 1.8 to 20, an IB parameter ranging from 0.92 to 1.05, and an ATREF profile characterized by one large peak. These polymers have the dart impact, tear strength, and optical properties of a metallocene-catalyzed LLDPE, but with improved processability, melt strength, and bubble stability, and can be used in blown film and other end-use applications.
Claims28
An ethylene polymer having:
- a Mw in a range from about 70,000 to about 200,000 g/mol;
- a ratio of Mz/Mw in a range from about 1.8 to about 20;
- an IB parameter in a range from about 0.92 to about 1.05;
- and
- a peak ATREF temperature in a range from about 68 to about 78° C.
An ethylene polymer having:
- a Mw in a range from about 70,000 to about 200,000 g/mol;
- a ratio of Mz/Mw in a range from about 1.8 to about 20;
- an IB parameter in a range from about 0.92 to about 1.05;
- and
- the following polymer fractions in an ATREF test:
- from about 0.5 to about 5 wt. % of the polymer eluted below a temperature of 40° C.;
- from about 20 to about 40 wt. % of the polymer eluted between 76 and 86° C.;
- from about 7 to about 20 wt. % of the polymer eluted above a temperature of 86° C.;
- and the remaining percentage of the polymer eluted between 40 and 76° C.
An ethylene polymer having:
- a Mw in a range from about 70,000 to about 200,000 g/mol;
- a ratio of Mz/Mw in a range from about 1.8 to about 20;
- an IB parameter in a range from about 0.92 to about 1.05;
- a peak ATREF temperature in a range from about 70 to about 77° C., and no other peaks on the ATREF curve above a dW/dT of 2 in height;
- and
- the following polymer fractions in an ATREF test:
- from about 0.1 to about 3 wt. % of the polymer eluted below a temperature of 40° C.;
- from about 25 to about 38 wt. % of the polymer eluted between 76 and 86° C.;
- from about 9 to about 18 wt. % of the polymer eluted above a temperature of 86° C.;
- and the remaining percentage of the polymer eluted between 40 and 76° C.
A blown film comprising an ethylene polymer having:
- a Mw in a range from about 70,000 to about 200,000 g/mol;
- a ratio of Mz/Mw in a range from about 1.8 to about 20;
- and
- an IB parameter in a range from about 0.92 to about 1.05;
- wherein the film has:
- an average thickness in a range from about 0.5 to about 8 mils;
- a haze of less than or equal to about 8%;
- a MD shrink in a range from about 65 to about 90%;
- and
- a TD shrink in a range from about 2 to about 30%.
Dependencies are inferred from the claim text.