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

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.