Multimodal polyethylene

1. A multimodal polyethylene copolymer suitable for use in cable insulation comprising:

(I) 45 to 55 wt % of a lower molecular weight component which is an ethylene copolymer of ethylene and at least one C3-12 alpha olefin comonomer, said LMW component having a density of 940 to 962 kg/m 3 and an MFR 2 of 50 to 500 g/10 min;

(II) 55 to 45 wt % of a higher molecular weight ethylene copolymer component of ethylene and at least one C3-12 alpha olefin comonomer;

wherein said multimodal polyethylene copolymer has a density of 940 to 950 kg/m 3 , an MFR 2 of 0.05 to 2.0 g/10 min and at least one of a crystallization half time>3.0 mins at 120.5° C., a crystallization half time>5.0 mins at 121° C. or a crystallization half time>10.0 mins at 122° C., when measured according to ISO 11357-7.

2. A multimodal polyethylene copolymer as claimed in claim 1 having a density of 942 to 948 kg/m 3 .

3. A multimodal polyethylene copolymer as claimed in claim 1 having an MFR 2 of 0.2 to 2.0 g/10 min.

4. A multimodal polyethylene copolymer as claimed in claim 1 prepared using a Ziegler Natta catalyst.

5. A multimodal polyethylene copolymer as claimed in claim 1 wherein said HMW copolymer component comprises at least one of 1-butene, 1-hexene and 1-octene.

6. A multimodal polyethylene copolymer as claimed in claim 1 having 47 to 53 wt % of a HMW component (II) and 53 to 47 wt % LMW component (I).

7. A multimodal polyethylene copolymer as claimed in claim 1 having a shear thinning index (SHI 5.0/300) in the range of 20.0 to 50.0.

8. A multimodal polyethylene copolymer as claimed in claim 1 wherein said LMW polymer is a copolymer with the comonomer 1-butene.

9. A multimodal polyethylene copolymer as claimed in claim 1 having at least two of

(i) a crystallization half time>3.0 mins at 120.5° C.,

(ii) a crystallization half time>5.0 mins at 121° C. or

(iii) a crystallization half time>10.0 mins at 122° C.

10. A multimodal polyethylene copolymer as claimed in any preceding claim having wherein the LMW component has an MFR 2 of 200 to 400 g/10 min.

11. A multimodal polyethylene copolymer as claimed in claim 1 wherein the LMW component has a density of 950 to 962 kg/m 3 .

12. A multimodal polyethylene copolymer as claimed in claim 1 wherein the copolymer has a petroleum jelly adsorption of 5.0 to 9.0 wt %.

13. A cable comprising a conductor surrounded by an insulation layer comprising a copolymer as claimed in claim 1 .

14. A cable as claimed in claim 13 further comprising at least one filler.

15. A cable as claimed in claim 13 which is a data cable or telecommunications cable.

16. A multimodal polyethylene copolymer as claimed in claim 1 having a density of 943 to 947 kg/m 3 .

17. A multimodal polyethylene copolymer as claimed in claim 1 having an MFR 2 of 0.5 to 1.5 g/10 min.

18. A multimodal polyethylene copolymer as claimed in claim 1 having a shear thinning index (SHI 5.0/300) in the range of 25.0 to 45.0.

19. A multimodal polyethylene copolymer as claimed in claim 9 having all of

(i) a crystallization half time>3.0 mins at 120.5° C.,

(ii) a crystallization half time>5.0 mins at 121° C. or

(iii) a crystallization half time>10.0 mins at 122° C.

20. A multimodal polyethylene copolymer as claimed in claim 9 having a crystallization half time>11.5 mins at 122° C.

21. A multimodal polyethylene copolymer as claimed in claim 1 wherein the copolymer has a petroleum jelly adsorption of 5.5 to 8.5 wt %.

22. A cable as claimed in claim 13 , wherein said insulation layer is adjacent said conductor.

23. A cable as claimed in claim 14 wherein said filler is petroleum jelly.