Polyethylene composition and film

Patent metadata

Field	Value
Publication number	US-11279819-B2
Application number	US-201916508440-A
Country	US
Kind code	B2
Filing date	Jul 11, 2019
Priority date	Jul 11, 2018
Publication date	Mar 22, 2022
Grant date	Mar 22, 2022

Abstract

In some embodiments disclosed herein are polyethylene composition including a first polyethylene which is an ethylene copolymer having a weight average molecular weight of from 70,000 to 250,000 and a molecular weight distribution Mw/Mn of <2.3, a second polyethylene which is an ethylene copolymer or homopolymer having a weight average molecular weight of less than 75,000 and a molecular weight distribution Mw/Mn of <2.3, a third polyethylene which is an ethylene copolymer or homopolymer having a weight average molecular weight of less than 75,000 and a molecular weight distribution Mw/Mn of <2.3, and a fourth polyethylene which is an ethylene copolymer or homopolymer having a weight average molecular weight of from 100,000 to 250,000 and a molecular weight distribution Mw/Mn of >2.3, where the first polyethylene has more short chain branching than the second polyethylene or the third polyethylene. The polyethylene composition may have a soluble fraction in a CEF analysis of at least 7.5 weight percent. Film made from the polyethylene composition may have a machine direction 1% secant modulus of 200 MPa (at a film thickness of about 1 mil) and an oxygen transmission rate (OTR) of ≥550 cm3 per 100 inch per day (at a film thickness of about 1 mil). Film made from the polyethylene composition retains much of its dart impact performance on downgauging from a thickness of 1 mil to a thickness of 0.75 mil.

First claim

What is claimed is:

1. A polyethylene composition comprising:
from 15 to 75 wt % of a first polyethylene which is an ethylene copolymer, the first polyethylene having a weight average molecular weight MW of from 70,000 to 250,000, a molecular weight distribution M w /M n of <2.3 and from 5 to 100 short chain branches per thousand carbon atoms;
from 5 to 50 wt % of a second polyethylene which is an ethylene copolymer or an ethylene homopolymer, the second polyethylene having a weight average molecular weight MW of less than 75,000, a molecular weight distribution M w /M n of <2.3 and from 0 to 20 short chain branches per thousand carbon atoms; and
from 5 to 50 wt % of a third polyethylene which is an ethylene copolymer or an ethylene homopolymer, the second polyethylene having a weight average molecular weight MW of less than 75,000, a molecular weight distribution M w /M n of <2.3 and from 0 to 20 short chain branches per thousand carbon atoms; and
from 5 to 60 wt % of a fourth polyethylene which is an ethylene copolymer or an ethylene homopolymer, the fourth polyethylene having a weight average molecular weight Mw of from 100,000 to 250,000, a molecular weight distribution M w /M n of >2.3 and from 0 to 75 short chain branches per thousand carbon atoms; wherein
the number of short chain branches per thousand carbon atoms in the first polyethylene (SCB PE-1 ) is greater than the number of short chain branches per thousand carbon atoms in the second polyethylene (SCB PE-2 ), the third polyethylene (SCB PE-3 ) and the fourth polyethylene (SCB PE-4 );
the number of short chain branches per thousand carbon atoms in the fourth polyethylene (SCB PE-4 ) is greater than the number of short chain branches per thousand carbon atoms in the second polyethylene (SCB PE-2 ) and the third polyethylene (SCB PE-3 );
the weight average molecular weight of the second polyethylene and the third polyethylene are less than the weight average molecular weight of the first polyethylene and the fourth polyethylene; and
the weight average molecular weight of the second polyethylene and the third polyethylene are within 20,000 units of each other; wherein,
the polyethylene composition has a density of ≤0.939 g/cm 3 , and a melt index I 2 , determined at 190° C., of from 0.1 to 10 dg/min.

2. The polyethylene composition of claim 1 wherein the polyethylene composition has a soluble fraction in a crystallization elution fractionation (CEF) analysis of at least 7.5 weight percent.

3. The polyethylene composition of claim 1 wherein the polyethylene composition has a soluble fraction in a crystallization elution fractionation (CEF) analysis of at least 10 weight percent.

4. The polyethylene composition of claim 1 wherein the polyethylene composition has a melt flow ratio, I 21 /I 2 of greater than 40.

5. The polyethylene composition of claim 1 wherein the weight average molecular weight of the second polyethylene and the third polyethylene are within 15,000 units of each other.

6. The polyethylene composition of claim 1 wherein the weight average molecular weight of the second polyethylene and the third polyethylene are within 10,000 units of each other.

7. The polyethylene composition of claim 1 wherein the polyethylene composition has a melting peak temperature in a differential scanning calorimetry (DSC) analysis at above 125° C.

8. The polyethylene composition of claim 1 wherein the polyethylene composition has at least two melting peaks in a differential scanning calorimetry (DSC) analysis.

9. The polyethylene composition of claim 1 wherein the first polyethylene has from 25 to 75 short chain branches per thousand carbon atoms.

10. The polyethylene composition of claim 1 wherein the second polyethylene is an ethylene homopolymer.

11. The polyethylene composition of claim 1 wherein the third polyethylene is an ethylene homopolymer.

12. The polyethylene composition of claim 1 wherein the fourth polyethylene is an ethylene copolymer and has from 5 to 35 short chain branches per thousand carbon atoms.

13. The polyethylene composition of claim 1 wherein the first polyethylene has a weight average molecular weight, Mw of from 75,000 to 200,000.

14. The polyethylene composition of claim 1 wherein the second polyethylene has a weight average molecular weight, Mw of from 12,000 to 45,000.

15. The polyethylene composition of claim 1 wherein the third polyethylene has a weight average molecular weight, Mw of from 12,000 to 40,000.

16. The polyethylene composition of claim 1 wherein the fourth polyethylene has a weight average molecular weight, Mw of from 100,000 to 200,000.

17. The polyethylene composition of claim 1 wherein the first polyethylene has a density of from 0.865 to 0.916 g/cm 3 .

18. The polyethylene composition of claim 1 wherein the second polyethylene is an ethylene homopolymer having a density of from 0.940 to 0.980 g/cm 3 .

19. The polyethylene composition of claim 1 wherein the third polyethylene is an ethylene homopolymer having a density of from 0.940 to 0.980 g/cm 3 .

20. The polyethylene composition of claim 1 wherein the fourth polyethylene is an ethylene copolymer having a density of from 0.880 to 0.936 g/cm 3 .

21. The polyethylene composition of claim 1 wherein the first polyethylene is present in from 20 to 70 wt %.

22. The polyethylene composition of claim 1 wherein the second polyethylene is present in from 10 to 40 wt %.

23. The polyethylene composition of claim 1 wherein the third polyethylene is present in from 10 to 40 wt %.

24. The polyethylene composition of claim 1 wherein the fourth polyethylene is present in from 5 to 50 wt %.

25. The polyethylene composition of claim 1 wherein the first polyethylene has a CDBI 50 of at least 75 wt %.

26. The polyethylene composition of claim 1 wherein the fourth polyethylene is a copolymer with a CDBI 50 of less than 75 wt %.

27. The polyethylene composition of claim 1 wherein the first polyethylene is a homogeneously branched ethylene copolymer.

28. The polyethylene composition of claim 1 wherein the fourth polyethylene is a heterogeneously branched ethylene copolymer.

29. The polyethylene composition of claim 1 wherein the first polyethylene is a made with a single site catalyst.

30. The polyethylene composition of claim 1 wherein the second polyethylene is made with a single site catalyst.

31. The polyethylene composition of claim 1 wherein the third polyethylene is made with a single site catalyst.

32. The polyethylene composition of claim 1 wherein the fourth polyethylene is made with a Ziegler-Natta catalyst.

33. The polyethylene composition of claim 1 wherein the polyethylene composition has a molecular weight distribution M w /M n of from 2.3 to 8.0.

34. The polyethylene composition of claim 1 wherein the polyethylene composition has a molecular weight distribution M w /M n of from 2.5 to 6.5.

35. The polyethylene composition of claim 1 wherein the polyethylene composition has a density of <0.935 g/cm 3 .

36. The polyethylene composition of claim 1 wherein the polyethylene composition has a density of from 0.880 to 0.932 g/cm 3 .

37. The polyethylene composition of claim 1 wherein the pol

Assignees

• Nova Chem Int Sa

Inventors

• Wang Xiaochuan
• Zoricak Peter
• Molloy Brian
• Wang Qinyan
• Vanasseldonk Lawrence
• Aubee Norman

Classifications

• C08J2323/06

  Polyethene · CPC title

• C08F4/65908

  in combination with an ionising compound other than alumoxane, e.g. (C6F5)4B-X+ · CPC title

• C08L23/08 Primary

  Copolymers of ethene (C08L23/16 takes precedence) · CPC title

• C08L2314/02

  Ziegler natta catalyst · CPC title

• C08L2205/03

  containing three or more polymers in a blend · CPC title