Disentangled high or ultrahigh molecular weight polyethylene prepared with Ziegler-Natta catalyst

Patent metadata

Field	Value
Publication number	US-9676877-B2
Application number	US-201515021113-A
Country	US
Kind code	B2
Filing date	Feb 6, 2015
Priority date	Feb 13, 2014
Publication date	Jun 13, 2017
Grant date	Jun 13, 2017

Abstract

Disentangled high or ultrahigh molecular weight polyethylene ((U)HMWPE) being produced with a Ziegler-Natta catalyst, characterized by (i) a factor for the normalized elastic modulus G′ 0 /G′ P of less than 0.95 determined in a dynamic time sweep measurement at 180° C. with constant strain of 0.5% at fixed frequency of 10 rad/s for at least 3600 s, whereby G′ 0 is the elastic shear modulus measured at t 0 directly after melting the sample and G′ p is the maximum plateau modulus.

First claim

The invention claimed:

1. A disentangled high or ultrahigh molecular weight polyethylene ((U)HMWPE) being produced with a Ziegler-Natta catalyst, characterized by
(i) a factor for the normalized elastic modulus G′ 0 /G′ p of less than 0.95 determined in a dynamic time sweep measurement at 180° C. with constant strain of 0.5% at fixed frequency of 10 rad/s for at least 3600 s, whereby G′ 0 is the elastic shear modulus measured at t 0 directly after melting the sample and G′ p is the maximum plateau modulus.

2. The disentangled high or ultrahigh molecular weight polyethylene according to claim 1 , being further characterized by
(i) an intrinsic viscosity of at least 8.0 dl/g
(ii) a nominal viscosity molecular weight (Mv) of at least 1.0*10 6 g/mol and
(iii) a molecular weight of (M w ) of at least 0.5*10 6 g/mol.

3. The disentangled high or ultrahigh molecular weight polyethylene according to claim 1 , wherein the polyethylene is either a homopolymer or a copolymer with up to 2.0 mol % of a C 3 -C 20 -alpha olefin comonomer.

4. The disentangled high or ultrahigh molecular weight polyethylene according to claim 3 , further characterized by being a homopolymer with a melting temperature Tm 1 , measured according to ISO 11357-3 after the first heating run, of >140.0° C.

5. The disentangled high or ultrahigh molecular weight polyethylene according claim 1 , wherein the factor for the normalized elastic modulus G′ 0 /G′ p is less than 0.90.

6. The disentangled high or ultrahigh molecular weight polyethylene according to claim 2 , wherein the polyethylene has
(i) an intrinsic viscosity of at least 10.0 dl/g,
(ii) a nominal viscosity molecular weight (Mv) of at least 1.2*10 6 g/mol and
(iii) a molecular weight of (M w ) of at least 0.8*10 6 g/mol.

7. The disentangled high or ultrahigh molecular weight polyethylene according to claim 4 , wherein the polyethylene has a melting temperature Tm 1 , measured according to ISO 11357-3 after the first heating run, of >140.5° C.

8. The disentangled high or ultrahigh molecular weight polyethylene according to claim 1 , wherein the polyethylene has a a complex viscosity η* 0.05 at a shear stress of 0.05 rad/s at 190° C. in the range of 1,000,000 Pa·s to 30,000,000 Pa·s.

9. A process for the preparation of a disentangled high or ultrahigh molecular weight polyethylene characterized by (i) a factor for the normalized elastic modulus G′ 0 /G′ p of less than 0.95 determined in a dynamic time sweep measurement at 180° C. with constant stain of 0.5% at fixed frequency of 10 rad/s for at least 3600s, whereby G′ 0 is the elastic shear modulus measured at t 0 directly after melting the sample and G′ p is the maximum plateau modulus, the process comprising:
polymerizing ethylene, optionally in the presence of a C 3 -C 20 alpha olefin comonomer, in a slurry phase reactor in an inert hydrocarbon diluent at a temperature of 10 to 100° C. in the presence of a Ziegler-Natta catalyst and a cocatalyst, but in the absence of hydrogen.

10. The process according to claim 9 , wherein the inert hydrocarbon diluent is a C 1 -C 4 hydrocarbon or a mixture therefrom.

11. The process according to claim 9 , wherein the temperature is 30 to 85° C.

12. A method for the producing a pipe comprising:
extruding a polyethylene blend comprising a disentangled high or ultrahigh molecular weight polyethylene and a high density polyethylene;
wherein the disentangled high or ultrahigh molecular weight polyethylene is produced with a Ziegler-Natta catalyst and characterized by (i) a factor for the normalized elastic modulus G′ 0 /G′ p of less that 0.95 determined in a dynamic time sweep measurement at 180° C. with constant strain of 0.5% at fixed frequency of 10 rad/s for at least 3600s, whereby G′ 0 is the elastic shear modulus measured at t 0 directly after melting the sample and G′ p is the maximum plateau modulus.

13. The disentangled high or ultrahigh molecular weight polyethylene according to claim 2 , wherein the polyethylene has a complex viscosity η* 0.05 at a shear stress of 0.05 rad/s at 190° C. in the range of 1,000,000 Pa·s to 30,000,000 Pa·s.

14. The process according to claim 10 , wherein the temperature is 30 to 85° C.

15. A method for the production of an article comprising:
blending a disentangled high or ultrahigh molecular weight polyethylene and a high density polyethylene;
wherein the disentangled high or ultrahigh molecular weight polyethylene is produced with a Ziegler-Natta catalyst, characterized by
(i) a factor for the normalized elastic modulus G′ 0 /G′ p of less than 0.95 determined in a dynamic time sweep measurement at 180° C. with constant strain of 0.5% at fixed frequency of 10 rad/s for at least 3600s, whereby G′ 0 is the elastic shear modulus measured at to directly after melting the sample and G′ p is the maximum plateau modulus;
(ii) an intrinsic viscosity of at least 8.0 dl/g;
(iii) a nominal viscosity molecular weight (Mv) of at least 1.01*10 6 g/mol; and
(iv) a molecular weight of (M w ) of at least 0.5*10 6 g/mol.

16. The disentangled high or ultrahigh molecular weight polyethylene according claim 1 , wherein the factor for the normalized elastic modulus G′ 0 /G′ p is less than 0.85.

17. The disentangled high or ultrahigh molecular weight polyethylene according to claim 4 , wherein the polyethylene has a melting temperature Tm 1 , measured according to ISO 11357-3 after the first heating run, of >141.0° C.

18. The disentangled high or ultrahigh molecular weight polyethylene according claim 1 , wherein the factor for the normalized elastic modulus G′ 0 /G′ p is less than 0.80.

19. The disentangled high or ultrahigh molecular weight polyethylene according claim 1 , wherein the polyethylene has a nominal viscosity molecular weight (Mv) within a range of from 1.3*10 6 g/mol to 5.5*10 6 g/mol.

20. The disentangled high or ultrahigh molecular weight polyethylene according claim 1 , wherein the polyethylene has a molecular weight of (Mw) within a range of from 1.01*10 6 g/mol to 2.5*10 6 g/mol.

Assignees

• Borealis Ag

Inventors

• Hjertberg Thomas
• Albunia Alexandra Romina
• Liu Yi
• Dou Qizheng

Classifications

• C08L23/06

  Polyethylene · CPC title

• C08F2500/01

  High molecular weight, e.g. >800,000 Da. · CPC title

• C08L2207/062

  HDPE · CPC title

• C08L2314/02

  Ziegler natta catalyst · CPC title

• C08F10/02 Primary

  Ethene · CPC title