Medium density polyethylene compositions

Patent metadata

Field	Value
Publication number	US-11066499-B2
Application number	US-202017068486-A
Country	US
Kind code	B2
Filing date	Oct 12, 2020
Priority date	Mar 11, 2013
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

An ethylene alpha-olefin copolymer having (a) a density of from about 0.910 g/cc to about 0.940 g/cc; (b) a weight average molecular weight of from about 150,000 g/mol to about 300,000 g/mol; and (c) a melt index at a load of 2.16 kg of from about 0.01 dg/10 min. to about 0.5 dg/min.; wherein a 1 mil blown film formed from the polymer composition is characterized by (i) a Dart Impact strength greater than about 175 g/mil; (ii) an Elmendorf machine direction tear strength greater than about 20 g/mil; and (iii) an Elmendorf transverse direction tear strength greater than about 475 g/mil.

First claim

What is claimed is:

1. An ethylene alpha-olefin copolymer having:
(a) a density of from about 0.910 g/cc to about 0.940 g/cc;
(b) a weight average molecular weight of from about 150,000 g/mol to about 300,000 g/mol;
(c) a CY-a value of from about 0.35 to about 0.65;
(d) a ratio of high load melt index (HLMI) to melt index (MI) of from about 100 to about 2500, wherein the copolymer has an HLMI of from about 4 dg/min to about 25 dg/min when tested in accordance with ASTM D1238 under a force of 21.6 kg at 190° C., and wherein the MI is measured in accordance with ASTM D1238 under a force of 2.16 kg at 190° C.;
(e) a 1% secant modulus in the machine direction of from 90,000 psi to about 116,000 psi when tested in accordance with ASTM D882; and
(f) a molecular weight distribution of from about 4 to less than about 40.

2. The copolymer of claim 1 having a 2% secant modulus in the machine direction of from 77,297 psi to 81,479 psi when tested in accordance with ASTM D882.

3. The copolymer of claim 1 having a 1% secant modulus in the transverse direction of from about 110,000 psi to about 180,000 psi when tested in accordance with ASTM D882.

4. The copolymer of claim 1 having a 2% secant modulus in the transverse direction of from about 111,707 psi to 113,967 psi when tested in accordance with ASTM D882.

5. The copolymer of claim 1 having a yield strain in the machine direction of less than about 8% when tested in accordance with ASTM D882.

6. The copolymer of claim 1 having a yield strain in the transverse direction of from about 2% to about 5% when tested in accordance with ASTM D882.

7. The copolymer of claim 1 having a moisture vapor transmission rate of less than about 1.3 g-mil/100 in 2 -day when tested in accordance with ASTM F1249 at 100° F. and 90% relative humidity using a test specimen having a 1 mil thickness.

8. The copolymer of claim 1 having an oxygen transmission rate of less than about 525 cc/100 in 2 when tested in accordance with ASTM D3985 using a test specimen having a 1 mil thickness.

9. The copolymer of claim 1 which when extruded has a neck height:die diameter ratio of from about 6:1 to about 10:1.

10. A composition comprising the copolymer of claim 1 and less than about 1 wt. % nonpolymeric additives based on the total weight of the composition.

11. An ethylene alpha-olefin copolymer having:
(a) a density of from about 0.910 g/cc to about 0.940 g/cc;
(b) a ratio of high load melt index (HLMI) to melt index (MI) of from about 100 to about 2500, wherein the copolymer has an HLMI of from about 4 dg/min to about 25 dg/min when tested in accordance with ASTM D1238 under a force of 21.6 kg at 190° C., and wherein the MI is measured in accordance with ASTM D1238 under a force of 2.16 kg at 190° C.;
(c) a CY-a value of from about 0.35 to about 0.65;
(d) an oxygen transmission rate of less than about 525 cc/100 in 2 when tested in accordance with ASTM D3985 using a test specimen having a 1 mil thickness; and
(e) a molecular weight distribution of from about 4 to less than about 40.

12. The copolymer of claim 11 having a moisture vapor transmission rate of less than about 1.3 g-mil/100 in 2 -day when tested in accordance with ASTM F1249 at 100° F. and 90% relative humidity using a test specimen having a 1 mil thickness.

13. The copolymer of claim 11 having:
(i) a 1% secant modulus in the machine direction of from about 90,000 psi to about 116,000 psi when tested in accordance with ASTM D882;
(ii) a 2% secant modulus in the machine direction of from 77,297 psi to 81,479 psi when tested in accordance with ASTM D882;
(iii) a break strength in the transverse direction of from about 4300 psi to about 10,000 psi when tested in accordance with ASTM D882;
(iv) a break strength in the machine direction of from about 6500 psi to about 13,500 psi when tested in accordance with ASTM D882; and
(v) a molecular weight distribution of from about 4 to less than about 40.

14. The copolymer of claim 11 having a 2% secant modulus in the transverse direction of from about 111,707 psi to 113,967 psi when tested in accordance with ASTM D882.

15. The copolymer of claim 11 having a melt index at a load of 5.0 kg of from about 0.01 dg/min to about 1 dg/min.

16. The copolymer of claim 11 having a yield strain in the machine direction of less than about 8% when tested in accordance with ASTM D882.

17. The copolymer of claim 11 having a yield strain in the transverse direction of from about 2% to about 5% when tested in accordance with ASTM D882.

18. The copolymer of claim 11 having an Elmendorf machine direction tear strength of from about 10 g to 90 g when tested in accordance with ASTM D1922 using a test specimen having a 1 mil thickness; and an Elmendorf transverse direction tear strength greater than about 475 g/mil when tested in accordance with ASTM D1922 using a test specimen having a 1 mil thickness.

19. The copolymer of claim 11 having a molecular weight distribution of from about 4 to about 30.

20. The copolymer of claim 11 having an Eta(0) value of from about 1×10 4 Pa·s to about 5×10 5 Pa·s.

21. An ethylene alpha-olefin copolymer having:
(a) a density of from about 0.910 g/cc to about 0.940 g/cc;
(b) a ratio of high load melt index (HLMI) to melt index (MI) of from about 100 to about 2500; wherein the copolymer has an HLMI of from about 4 dg/min to about 25 dg/min when tested in accordance with ASTM D1238 under a force of 21.6 kg at 190° C., and wherein the MI is measured in accordance with ASTM D1238 under a force of 2.16 kg at 190° C.;
(c) a CY-a value of from about 0.35 to about 0.65;
(d) a molecular weight distribution of from about 4 to about 30.

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Sukhadia Ashish M
• St Jean Guylaine
• Yang Qing
• Mcdaniel Max P

Classifications

• C08J5/18 Primary

  Manufacture of films or sheets · CPC title

• C08F210/02

  Ethene · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• C08L23/0807

  with unsaturated hydrocarbons only containing four or more carbon atoms · CPC title

• C08J2323/08

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