Polyethylene compositions

• US 8,378,029 B2
• Filed: 07/07/2009
• Issued: 02/19/2013
• Est. Priority Date: 06/02/2005
• Status: Active Grant

• Current Assignee: Univation Technologies LLC (Dow, Inc.)
• Original Assignee: Univation Technologies LLC (Dow, Inc.)
• Inventors: Liu, Han-Tai, Mure, Cliff R.
• Primary Examiner(s): Nutter, Nathan M
• Application Number:
  US12/999,812
• Publication Number:
  US 20110118417A1
• Time in Patent Office: 1,323 Days
• Field of Search: 525/191, 525/240
• US Class Current: 525/191
• CPC Class Codes: C08F 10/00 Homopolymers and copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
• CPC Class Codes: C08F 10/02 Ethene
• CPC Class Codes: C08F 110/02 Ethene
• CPC Class Codes: C08F 210/16 Copolymers of ethene with alpha-alkenes, e.g. EP rubbers
• CPC Class Codes: C08F 2500/01 High molecular weight, e.g. >800,000 Da.
• CPC Class Codes: C08F 2500/05 Bimodal or multimodal molecular weight distribution
• CPC Class Codes: C08F 2500/07 High density, i.e. > 0.95 g/cm3
• CPC Class Codes: C08F 2500/11 Melt tension or melt strength
• CPC Class Codes: C08F 2500/12 Melt flow index or melt flow ratio
• CPC Class Codes: C08F 4/64148 NN(R)N
• CPC Class Codes: C08F 4/659 Component covered by group C08F4/64 containing a transition metal-carbon bond C08F4/64003 - C08F4/64196 take precedence
• CPC Class Codes: C08F 4/65904 in combination with another component of C08F4/64
• CPC Class Codes: C08F 4/65912 in combination with an organoaluminium compound
• CPC Class Codes: C08F 4/65925 two cyclopentadienyl rings being mutually non-bridged
• CPC Class Codes: C08L 2205/02 containing two or more polymers of the same C08L -group
• CPC Class Codes: C08L 23/04 Homopolymers or copolymers of ethene
• CPC Class Codes: C08L 2666/06 Homopolymers or copolymers of unsaturated hydrocarbons; Derivatives thereof
• CPC Class Codes: F16L 9/12 of plastics with or without reinforcement F16L9/16 - F16L9/22 take precedence

Abstract

Provided are various compositions, including but not limited to a bimodal polyethylene composition having a density of 0.940 g/cc or more, the composition comprising a high molecular weight polyethylene component and a low molecular weight polyethylene component, wherein the composition qualifies as a PE 100 material such that in accordance with ISO 1167 a pipe formed from the composition that is subjected to internal pipe resistance has an extrapolated stress of 10 MPa or more when the internal pipe resistance curve is extrapolated to 50 or 100 years in accordance with ISO 9080:2003(E), and wherein the melt strength is greater than 18 cN.

Claims

1. A bimodal polyethylene composition having a density of 0.940 g/cc or more, the composition comprising a high molecular weight polyethylene component and a low molecular weight polyethylene component wherein the high and low molecular weight polyethylene components are formed in a single reactor, wherein:

the composition qualifies as a PE 100 material such that in accordance with ISO 1167 a pipe formed from the composition that is subjected to internal pipe resistance has an extrapolated stress of 10 MPa or more when the internal pipe resistance curve is extrapolated to 50 or 100 years in accordance with ISO 9080;

2003(E);

the composition has a melt strength of 18 cN or greater; and

the ratio of the weight average molecular weight of the high molecular weight component (Mw_HMW) to the weight average molecular weight of the low molecular weight component (Mw_LMW) of the composition is greater than 15;

1 and less than 28;

1.

2. The composition of claim 1 in which the melt strength is greater than 20 cN.

3. The composition of claim 1 in which the melt strength is greater than 22 cN.

4. The composition of claim 1 in which the complex viscosity at 0.01 s-1 is greater than 3.5×

10⁵ Pa-s.

5. The composition of claim 1 in which the complex viscosity at 0.1 s-1 is greater than 1.5×

10⁵ Pa-s.

6. The composition of claim 1 having an overall PDI of 15 to 40.

7. The composition of claim 1 in which the high molecular weight component is present in an amount of 45 to 60 wt. .

8. The composition of claim 1 in which the average molecular weight (Mw) of the low molecular weight polyethylene component is from 5,000 to 35,000.

9. The composition of claim 1 in which the average molecular weight (Mw) of the high molecular weight polyethylene component is from 400,000 to 700,000.

10. The composition of claim 1 having an FI (121) of from 4 to 10 g/10 min.

11. The composition of claim 1 in which the high molecular weight polyethylene component has a density of 0.945 g/cc or less.

12. The composition of claim 1 in which the low molecular weight polyethylene component has a density of 0.940 g/cc or more.

13. The composition of claim 1 in which the high molecular weight polyethylene component comprises a polyethylene that comprises a comonomer being butene, hexene, octene, and mixtures thereof, wherein the comonomer is present in the amount of more than 1.0 wt of the polyethylene.

14. The composition of claim 1 in which the low molecular weight polyethylene component comprises a polyethylene that comprises a comonomer being butene, hexene, octene, and mixtures thereof, wherein the comonomer is present in the amount of less than 3.0 wt of the polyethylene.

15. The composition of claim 1 wherein the extrapolated stress is 10.5 MPa or more when extrapolated to 50 or 100 years in accordance with ISO 9080:

2003(E).

16. The composition of claim 1 wherein the high and low molecular weight polyethylene components are formed in gas phase polymerization.

17. The composition of claim 1 wherein the composition is made from polymerization conducted in the presence of a bimodal catalyst system that comprises a metallocene based catalyst.

18. The composition of claim 1 wherein the high and low molecular weight polyethylene components are formed from polymerization conducted in the presence of a bimodal catalyst system that comprises bis(2-trymethylphenylamido)ethyl)amine zirconium dibenzyl;

bis(2-(pentamethyl-phenylamido)ethyl)amine zirconium dibenzyl;

(pentamethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dichloride;

(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dichloride;

(tetramethylcyclopentadienyl)(n-propylcyclopentadienyl)zirconium dimethyl;

bis(2-pentamethylphenylamido)ethyl)zirconium dibenzyl;

or bis(2-pentamethylphenylamido)ethyl)zirconium dimethyl.