Polyethylene copolymer compositions and articles with barrier properties

Patent metadata

Field	Value
Publication number	US-11149137-B2
Application number	US-202016745985-A
Country	US
Kind code	B2
Filing date	Jan 17, 2020
Priority date	Dec 20, 2018
Publication date	Oct 19, 2021
Grant date	Oct 19, 2021

Abstract

A dual reactor solution polymerization process gives high density polyethylene compositions containing a first ethylene copolymer and a second ethylene copolymer. The polyethylene compositions can be used in the manufacture of injection molded closures or cast film having good barrier properties.

First claim

What is claimed is:

1. A polyethylene copolymer composition comprising:
(1) 90 to 30 wt % of a first ethylene copolymer having a melt index I 2 , of from 0.1 to 10 g/10 min; a molecular weight distribution M w /M n , of less than 3.0; and a density of from 0.930 to 0.960 g/cm 3 ; and
(2) 10 to 70 wt % of a second ethylene copolymer having a melt index I 2 , of greater than 10,000 g/10 min; a molecular weight distribution M w /M n , of less than 3.0; and a density higher than the density of the first ethylene copolymer, but less than 0.980 g/cm 3 ;
wherein the density of the second ethylene copolymer is less than 0.037 g/cm 3 higher than the density of the first ethylene copolymer; a ratio (SCB1/SCB2) of a number of short chain branches per thousand carbon atoms in the first ethylene copolymer (SCB1) to a number of short chain branches per thousand carbon atoms in the second ethylene copolymer (SCB2) is greater than 2.0; and wherein the polyethylene copolymer composition has a molecular weight distribution M w /M n , of from 2.0 to 10.0; a density of at least 0.949 g/cm 3 ; a high load melt index I 21 , of at least 300 g/10 min; a Z-average molecular weight Mz, of less than 200,000; a melt flow ratio I 21 /I 2 , of from 22 to 50; and a stress exponent of less than 1.40.

2. The polyethylene copolymer composition of claim 1 wherein the polyethylene composition has a melt index I 2 , of from 5.0 to 40.0 g/10 min.

3. The polyethylene copolymer composition of claim 1 wherein the density of the second ethylene copolymer is less than 0.030 g/cm 3 higher than the density of the first ethylene copolymer.

4. The polyethylene copolymer composition of claim 1 wherein the first ethylene copolymer has a melt index I 2 , of from 0.1 to 5.0 g/10 min.

5. The polyethylene copolymer composition of claim 1 wherein the second ethylene copolymer has a melt index I 2 , of from greater than 10,000 to 15,000 g/10 min.

6. The polyethylene copolymer composition of claim 1 wherein the polyethylene composition has a high load melt index I 21 , of from 300 to 850 g/10 min.

7. The polyethylene copolymer composition of claim 1 wherein the polyethylene composition has a bimodal molecular weight distribution as determined by gel permeation chromatography.

8. The polyethylene copolymer composition of claim 1 wherein the ratio (SCB1/SCB2) of the number of short chain branches per thousand carbon atoms in the first ethylene copolymer (SCB1) to the number of short chain branches per thousand carbon atoms in the second ethylene copolymer (SCB2) is at least 2.5.

9. The polyethylene copolymer composition of claim 1 wherein the polyethylene composition has a molecular weight distribution M w /M n , of from 3.0 to 8.0.

10. The polyethylene copolymer composition of claim 1 wherein the first ethylene copolymer has a density of from 0.936 to 0.952 g/cm 3 .

11. The polyethylene copolymer composition of claim 1 wherein the second ethylene copolymer has a density of from 0.959 to 0.976 g/cm 3 .

12. The polyethylene copolymer composition of claim 1 wherein the polyethylene composition has a density of from 0.953 to 0.970 g/cm 3 .

13. The polyethylene copolymer composition of claim 1 wherein the polyethylene composition has no long chain branching.

14. The polyethylene copolymer composition of claim 1 wherein the polyethylene composition has a composition distribution breadth index CDBI(50) of greater than 65 wt %.

15. The polyethylene copolymer composition of claim 1 wherein the polyethylene composition comprises:
from 80 to 35 wt % of the first ethylene copolymer; and
from 20 to 65 wt % of the second ethylene copolymer.

16. The polyethylene copolymer composition of claim 1 wherein the first and second ethylene copolymers are copolymers of ethylene and 1-octene.

17. The polyethylene copolymer composition of claim 1 wherein the polyethylene composition further comprises a nucleating agent.

18. The polyethylene copolymer composition of claim 17 wherein the nucleating agent is a salt of a dicarboxylic acid compound.

19. The polyethylene copolymer composition of claim 18 wherein the polyethylene composition comprises from 20 to 4000 ppm of the nucleating agent based on a combined weight of the first ethylene copolymer and the second ethylene copolymer.

20. An injection molded article comprising the polyethylene copolymer composition of claim 1 .

21. A compression molded article comprising the polyethylene copolymer composition of claim 1 .

22. A closure comprising the polyethylene copolymer composition of claim 1 .

23. A film comprising the polyethylene copolymer composition of claim 1 .

24. A cast film comprising the polyethylene copolymer composition of claim 1 .

25. The polyethylene copolymer composition of claim 17 , which when made into a PCO 1881 CSD closure, has an OTR of less than 0.0260 cm 3 /closure/day.

26. A film comprising the polyethylene copolymer composition of claim 17 and having a normalized OTR of ≤100 cm 3 /100 in 2 /day.

27. A film comprising the polyethylene copolymer composition of claim 17 and having a normalized WVTR of ≤0.280 g/100 in 2 /day.

28. A polyethylene copolymer composition comprising:
(1) 90 to 30 wt. % of a first ethylene copolymer having a melt index I 2 , of from 0.1 to 10 g/10 min; a molecular weight distribution M w /M n , of less than 3.0; and a density of from 0.930 to 0.960 g/cm 3 ; and
(2) 10 to 70 wt % of a second ethylene copolymer having a melt index I 2 , of greater than 10,000 g/10 min; a molecular weight distribution M w /M n , of less than 3.0; and a density higher than the density of the first ethylene copolymer, but less than 0.980 g/cm 3 ;
wherein the density of the second ethylene copolymer is less than 0.037 g/cm 3 higher than the density of the first ethylene copolymer; a ratio (SCB1/SCB2) of a number of short chain branches per thousand carbon atoms in the first ethylene copolymer (SCB1) to a number of short chain branches per thousand carbon atoms in the second ethylene copolymer (SCB2) is greater than 2.0; and wherein the polyethylene copolymer composition has a molecular weight distribution M w /M n , of from 2.0 to 10.0; a density of at least 0.949 g/cm 3 ; a high load melt index I 21 , of at least 300 g/10 min; a Z-average molecular weight Mz, of less than 200,000; a melt flow ratio I 21 /I 2 , of from 22 to 50; and a stress exponent of less than 1.40;
wherein the polyethylene copolymer composition is made by a process comprising contacting at least one single site polymerization catalyst system with ethylene under solution polymerization conditions in at least two polymerization reactors.

29. A process to prepare a polyethylene copolymer composition, the polyethylene copolymer composition comprising:
(1) 90 to 30 wt % of a first ethylene copolymer having a melt index I 2 , of from 0.1 to 10 g/10 min; a molecular weight distribution M w /M n , of less than 3.0; and a density of from 0.930 to 0.960 g/cm 3 ; and
(2) 10 to 70 wt % of a second ethylene copolymer having a melt index I 2 , of greater than 10,000 g/10 min; a molecular weight distribution M w /M n , of less than 3.0; and a density higher than the density of the first ethylene copolymer, but less than 0.980 g/cm 3 ;
wherein the density of the second ethylene copolymer is less than 0.037 g/cm 3 higher than the density of the first ethylene cop

Assignees

• Nova Chem Int Sa

Inventors

• Wang Xiaochuan
• Salomons Stephen

Classifications

• C08J5/18

  Manufacture of films or sheets · CPC title

• C08J2323/08

  Copolymers of ethene (C08J2323/16 takes precedence) · CPC title

• C08L2308/00

  Chemical blending or stepwise polymerisation process with the same catalyst · CPC title

• C08L2207/062

  HDPE · CPC title

• C08F210/02

  Ethene · CPC title