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US 2026/0242578 A1Published application
Density and chemical composition control for polymer with good stress crack properties
AssigneeExxonMobil Chemical Patents Inc.
InventorsMartin Antensteiner, Nathaniel B. Guy, Porter C. Shannon, Richard E. Pequeno
Life of this patent
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Abstract
Provided are polyethylene copolymers with improved stress crack resistance, methods for making such copolymers, and films made from the same. The polyethylene copolymers include at least 95 wt % ethylene and at most 5 wt % of at least one comonomer having 3 to 18 carbon atoms; and further have a 30% single point notched constant tensile load of at least 1,000 hours, a density of 0.931 to 0.936 g/cm3, a melt index (I2) of 0.1 to 0.5 g/10 min, and a 25-75 chemical composition distribution index of 0.3 or more.
Claims20
A process comprising:
- (a) continuously passing an input stream containing ethylene and an olefin comonomer having 3 to 18 carbon atoms through a fluidized-bed reactor under reaction conditions and in presence of a catalyst composition at a velocity sufficient to maintain a bed of solid particles in a suspended state in the reactor;
- (b) continuously withdrawing a cycle gas stream containing unreacted ethylene and olefin comonomer from the reactor;
- (c) compressing and cooling the cycle gas stream, and recycling the compressed and cooled cycle gas stream to the reactor;
- (d) controlling the cycle gas stream to include any induced condensing agents (ICAs) within a range from 2 to 10 mol % of the cycle gas stream;
- and
- (e) obtaining, from the reactor, a polyethylene copolymer having at least 95 wt % ethylene-derived units and 5 wt % or less units derived from the olefin comonomer;
- and further having 0.3 or greater of 25%-75% chemical composition distribution index (25-75 CCDI).
4 more elements
Dependencies are inferred from the claim text.