Polymers with improved processability for pipe applications

Patent metadata

Field	Value
Publication number	US-9828451-B2
Application number	US-201414522991-A
Country	US
Kind code	B2
Filing date	Oct 24, 2014
Priority date	Oct 24, 2014
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

A crosslinked metallocene-catalyzed polyethylene copolymer having a higher molecular weight (HMW) component and lower molecular weight (LMW) component wherein the HMW component is present in an amount of from about 10 wt. % to about 30 wt. % and wherein the LMW component is present in an amount of from about 70 wt. % to about 90 wt. %.

First claim

What is claimed is:

1. A crosslinked metallocene-catalyzed polyethylene copolymer having a higher molecular weight (HMW) component and lower molecular weight (LMW) component; wherein the HMW component is present in an amount of from 10 wt. % to 30 wt. %; wherein the LMW component is present in an amount of from 70 wt. % to 90 wt. %; wherein the copolymer has gels present in an amount of less than 300/sq. ft., wherein the gels have a size greater than 200 microns; wherein the copolymer has a high load melt index of from 6 g/10 min to 25 g/10 min, when tested in accordance with ASTM D1238 under a force of 21.6 kg; wherein the copolymer has a melt index of from 0.2 g/10 min to 0.8 g/10 min, when tested in accordance with ASTM D1238 under a force of 2.16 kg; and wherein the copolymer has a density of from 0.925 g/cc to 0.945 g/cc, when tested in accordance with ASTM D1505.

2. The copolymer of claim 1 which when tested in accordance with ASTM D638 and/or ISO 527 has a Young's modulus of from 120 kpsi to 190 kpsi.

3. The copolymer of claim 1 having a viscous relaxation time of from 0.5 s to about 8 s.

4. The copolymer of claim 1 having an η 0 (eta_0) of from 5.0×10 4 Pa-s to 8.0×10 5 Pa-s.

5. The copolymer of claim 1 having an η 100 (eta_100) of from 1,000 Pa-s to 4,000 Pa-s.

6. The copolymer of claim 1 which when tested in accordance with ASTM D638 and/or ISO 527 has a percent elongation at break of from 450% to 800%.

7. The copolymer of claim 1 which when tested in accordance with ASTM D638 and/or ISO 527 has a percent elongation at yield of from 8.0% to 20%.

8. The copolymer of claim 1 which when tested in accordance with ASTM D638 and/or ISO 527 has a tensile strength at break of from 3,500 psi to 6,000 psi.

9. The copolymer of claim 1 which when tested in accordance with ASTM D638 and/or ISO 527 has a tensile strength at yield of from 2,600 psi to 3,000 psi.

10. The copolymer of claim 1 which when tested in accordance with ASTM D3895 has an oxidative induction time of greater than 100 min.

11. The copolymer of claim 1 which when tested in accordance with ASTM D3895 has an oxidative induction temperature of greater than 220° C.

12. The copolymer of claim 1 which when tested in accordance with ASTM F2231 has a Charpy impact energy of from 0.9 J to 3.0 J.

13. The copolymer of claim 1 which when tested in accordance with ASTM F2231 has a Charpy temperature of from 35° C. to 10° C.

14. The copolymer of claim 1 which when tested in accordance with ASTM D638 has a tensile natural draw ratio of from 380% to 500%.

15. The copolymer of claim 1 which when tested in accordance with ASTM F1473 has a resistance to slow crack growth of greater than 500 h, wherein the resistance to slow crack growth is defined as the PENT failure time.

16. The copolymer of claim 1 which when tested in accordance with ISO 13477 has a S4 critical temperature of from 30° C. to 10° C. for a 2″DR11 pipe.

17. The copolymer of claim 1 which when tested in accordance with ISO 13477 has a S4 critical pressure of greater than 12 bar as determined at 0° C. for a 2″DR11 pipe.

18. The copolymer of claim 1 having a molecular weight distribution of from 4 to 18.

Assignees

• Chevron Phillips Chemical Co Lp

Inventors

• Rohatgi Vivek
• Inn Yongwoo
• Sukhadia Ashish M
• Yang Qing
• Deslauriers Paul J

Classifications

• C08L23/0815

  with aliphatic 1-olefins containing one carbon-to-carbon double bond · CPC title

• C08L2312/00

  Crosslinking · CPC title

• C08L2203/18

  used for pipes · CPC title

• C08F210/16 Primary

  Copolymers of ethene with alpha-alkenes, e.g. EP rubbers · 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