Silane crosslinkable polyethylene
Crosslinkable or crosslinked polymer compositions are provided, the compositions including a copolymer of ethylene and C 3 to C 12 alpha-olefin comonomer, the copolymer having a CDBI of at least 70%, a melt index I 2.16 of from 0.1 to 15 g/10 min, a density of from 0.910 to 0.940 g/cm 3 , a melt index ratio I 21.6 /I 2.16 of from 30 to 80, and an Mw/Mn ratio of from 2.5 to 5.5; and a silane grafting composition including a silane compound and a free radical initiator; or reaction products thereof. The crosslinkable or crosslinked compositions are particularly suitable for electrical applications, such as in insulating, semiconducting or jacketing layers of power cables, telecommunications cables, and combined power/telecommunications cables.
1. A coating layer for an electrical device comprising:
(a) a copolymer comprising polymerized ethylene monomer and C 3 to C 12 alpha-olefin comonomer, the copolymer having a CDBI of at least 70%, a melt index I 2.16 of from 0.1 to 15 g/10 min, a density of from 0.910 to 0.940 g/cm 3 , a melt index ratio I 21.6 /I 2.16 of from 30 to 80, and an Mw/Mn ratio of from 2.5 to 5.5;
(b) a silane grafting composition comprising a silane compound and a free radical initiator, the silane compound comprising an unsaturated group and a hydrolyzable group; and
(c) a silanol condensation catalyst;
or reaction products thereof.
2. The coating layer of claim 1 , wherein the alpha-olefin comonomer comprises 1-butene, 1-hexene or 1-octene.
3. The coating layer of claim 1 , wherein the CDBI of the ethylene copolymer is at least 75%.
4. The coating layer of claim 1 , wherein the CDBI of the ethylene copolymer is at least 80%.
5. The coating layer of claim 1 , wherein the melt index of the ethylene copolymer is from 0.3 to 10 g/10 min.
6. The coating layer of claim 1 , wherein the density of the ethylene copolymer is from 0.916 to 0.935 g/cm 3 .
7. The coating layer of claim 1 , wherein the melt index ratio I 21.6 /I 2.16 of the ethylene copolymer is from 35 to 80.
8. The coating layer of claim 1 , wherein the Mw/Mn ratio is from 2.8 to 4.5.
9. The coating layer of claim 1 , wherein the unsaturated group of the silane compound comprises a vinyl, allyl, isopropenyl, butenyl, cyclohexenyl, or γ-(meth)acryloxy allyl group.
10. The coating layer of claim 1 , wherein the hydrolyzable group of the silane compound comprises a hydrocarbyloxy, hydrocarbonyloxy or hydrocarbylamino group.
11. The coating layer of claim 1 , wherein the silane compound is a vinyl trialkoxysilane and the free radical initiator is an organic peroxide.
12. The coating layer of claim 1 , wherein the layer has a hot set value after 2 hours curing in 80° C. water of 70% or less.
13. The coating layer of claim 1 , wherein the layer has a hot set value after 30 days of 50% or less.
14. An electrical device comprising:
(a) an electrical conductor; and
(b) at least one layer surrounding at least a portion of the electrical conductor, the at least one layer comprising:
(a) a copolymer comprising polymerized ethylene monomer and C 3 to C 12 alpha-olefin comonomer, the copolymer having a CDBI of at least 70%, a melt index I 2.16 of from 0.1 to 15 g/10 min, a density of from 0.910 to 0.940 g/cm 3 , a melt index ratio I 21.6 /I 2.16 of from 30 to 80, and an Mw/Mn ratio of from 2.5 to 5.5;
(b) a silane grafting composition comprising a silane compound and a free radical initiator, the silane compound comprising an unsaturated group and a hydrolyzable group; and
(c) a silanol condensation catalyst;
or reaction products thereof.
15. The electrical device of claim 14 , wherein the alpha-olefin comonomer comprises 1-butene, 1-hexene or 1-octene.
16. The electrical device of claim 14 , wherein the CDBI of the ethylene copolymer is at least 75%.
17. The electrical device of claim 14 , wherein the CDBI of the ethylene copolymer is at least 80%.
18. The electrical device of claim 14 , wherein the melt index of the ethylene copolymer is from 0.3 to 10 g/10 min.
19. The electrical device of claim 14 , wherein the density of the ethylene copolymer is from 0.916 to 0.935 g/cm 3 .
20. The electrical device of claim 14 , wherein the melt index ratio I 21.6 /I 2.16 of the ethylene copolymer is from 35 to 80.
21. The electrical device of claim 14 , wherein the Mw/Mn ratio is from 2.8 to 4.5.
22. The electrical device of claim 14 , wherein the unsaturated group of the silane compound comprises a vinyl, allyl, isopropenyl, butenyl, cyclohexenyl, or γ-(meth)acryloxy allyl group.
23. The electrical device of claim 14 , wherein the hydrolyzable group of the silane compound comprises a hydrocarbyloxy, hydrocarbonyloxy or hydrocarbylamino group.
24. The electrical device of claim 14 , wherein the silane compound is a vinyl trialkoxysilane and the free radical initiator is an organic peroxide.
25. The electrical device of claim 14 , wherein the at least one layer has a hot set value after 2 hours curing in 80° C. water of 70% or less.
26. The electrical device of claim 14 , wherein the at least one layer has a hot set value after 30 days of 50% or less.
27. The electrical device of claim 14 , wherein the at least one layer is an insulating layer.
28. The electrical device of claim 14 , wherein the at least one layer is a semiconducting layer.
29. The electrical device of claim 14 , wherein the at least one layer is an outer jacket layer.
30. The electrical device of claim 14 , wherein the device is a power cable adapted to transport electricity at a voltage potential of less than or equal to 66 kV.
31. The electrical device of claim 14 , wherein the device is a power cable adapted to transport electricity at a voltage potential of less than or equal to 35 kV.
32. The electrical device of claim 14 , wherein the device is a power cable adapted to transport electricity at a voltage potential of less than or equal to 6 kV.
33. The electrical device of claim 14 , wherein the device is a power cable adapted to transport electricity at a voltage potential of less than or equal to 1 kV.
34. The electrical device of claim 14 , wherein the device is a telecommunications cable.
35. The electrical device of claim 14 , wherein the device is a combined power/telecommunications cable.
36. A method for making a coating for an electrical device, comprising:
polymerizing ethylene monomer and C 3 to C 12 alpha-olefin comonomer to produce a copolymer, the copolymer having a CDBI of at least 70%, a melt index I 2.16 of from 0.1 to 15 g/10 min, a density of from 0.910 to 0.940 g/cm 3 , a melt index ratio I 21.6 /I 2.16 of from 30 to 80, and an Mw/Mn ratio of from 2.5 to 5.5;
mixing the copolymer with a silane grafting composition comprising a silane compound and a free radical initiator to provide a silane grafted copolymer or reaction products thereof, the silane compound comprising an unsaturated group and a hydrolyzable group;
adding a silanol condensation catalyst to the silane grafter copolymer; and then
extruding the copolymer to provide the coating.
37. The method of claim 36 , wherein the alpha-olefin comonomer comprises 1-butene, 1-hexene or 1-octene.
38. The method of claim 36 , wherein the CDBI of the ethylene copolymer is at least 75%.
39. The method of claim 36 , wherein the CDBI of the ethylene copolymer is at least 80%.
40. The method of claim 36 , wherein the melt index of the ethylene copolymer is from 0.3 to 10 g/10 min.
41. The method of claim 36 , wherein the density of the ethylene copolymer is from 0.916 to 0.935 g/cm 3 .
42. The method of claim 36 , wherein the melt index ratio I 21.6 /I 2.16 of the ethylene copolymer is from 35 to 80.
43. The method of claim 36 , wherein the Mw/Mn ratio is from 2.8 to 4.5.
44. The method of claim 36 , wherein the unsaturated group of the silane compound comprises a vinyl, allyl, isopropenyl, butenyl, cyclohexenyl, or γ-(meth)acryloxy allyl group.
45. The method of claim 36 , wherein the hydrolyzable group of the silane compound comprises a hydrocarbyloxy, hydrocarbonyloxy or hydrocarbylamino group.
46. The method of claim 36 , wherein the silane compound is a vinyl trialkoxysilane and the free radical initiator is an organic peroxide.
47. The method of claim 36 , wherein the coating has a hot set value after 2 hours curing in 80° C. water of 70% or less.
48. The coating of claim 36 , wherein the coating has a hot set value after 30 days of 50% or less.