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US 10,519,304 B2Granted
Polyethylene compositions and closures made from them
AssigneeNOVA Chemicals (International) S.A.
InventorXiaoChuan Wang
Life of this patent
Estimating the term…
Abstract
A dual reactor solution process gives high density polyethylene compositions containing a first ethylene copolymer and a second ethylene copolymer and which have good processability, stiffness, and environmental stress crack resistance. The polyethylene compositions are suitable for compression molding or injection molding applications and are particularly useful in the manufacture of caps and closures for bottles.
Claims15
A closure, said closure comprising a bimodal polyethylene composition comprising:
- (1) 10 to 70 weight percent of a first ethylene copolymer having a melt index I2, of less than 0.4 g/10 min;
- a molecular weight distribution Mw/Mn, of less than 3.0;
- and a density of from 0.920 to 0.955 g/cm3;
- and
- (2) 90 to 30 weight percent of a second ethylene copolymer having a melt index I2, of from 100 to 10,000 g/10 min;
- a molecular weight distribution Mw/Mn, of less than 3.0;
- and a density higher than the density of said first ethylene copolymer, but less than 0.965 g/cm3;
- wherein the density of said second ethylene copolymer is less than 0.037 g/cm3 higher than the density of said first ethylene copolymer;
- the ratio (SCB1/SCB2) of the number of short chain branches per thousand carbon atoms in said first ethylene copolymer (SCB1) to the number of short chain branches per thousand carbon atoms in said second ethylene copolymer (SCB2) is greater than 1.0;
- and wherein said bimodal polyethylene composition has a molecular weight distribution Mw/Mn, of from 3 to 11;
- a density of at least 0.949 g/cm3;
- a melt index I2, of from 0.5 to 2.0 g/10 min, and a melt flow ratio 121/12 of from 40 to 100.
9 more elements
A bimodal polyethylene composition comprising:
- (1) 10 to 70 weight percent of a first ethylene copolymer having a melt index I2, of less than 0.4 g/10 min;
- a molecular weight distribution Mw/Mn, of less than 2.7;
- and a density of from 0.920 to 0.955 g/cm3;
- and
- (2) 90 to 30 weight percent of a second ethylene copolymer having a melt index I2, of from 100 to 10,000 g/10 min;
- a molecular weight distribution Mw/Mn, of less than 2.7;
- and a density higher than the density of said first ethylene copolymer, but less than 0.967 g/cm3;
- wherein the density of said second ethylene copolymer is less than 0.037 g/cm3 higher than the density of said first ethylene copolymer;
- the ratio (SCB1/SCB2) of the number of short chain branches per thousand carbon atoms in said first ethylene copolymer (SCB1) to the number of short chain branches per thousand carbon atoms in said second ethylene copolymer (SCB2) is greater than 1.0;
- and wherein said bimodal polyethylene composition has a molecular weight distribution Mw/Mn, of from 3 to 11;
- a density of at least 0.949 g/cm3;
- a melt index I2, of from 0.5 to 5.0 g/10 min, a melt flow ratio 121/12 of from 40 to 100, and an Mz of less than 400,000.
9 more elements
Dependencies are inferred from the claim text.