Process for manufacturing a power cable and power cable obtainable thereof
The present invention relates to a process for manufacturing a power cable, which power cable comprises at least one core comprising a conductor and an expanded and crosslinked insulation layer surrounding said conductor, wherein said process comprises the steps a) to d): a) providing a blend of: a polymer composition comprising a polyolefin material, which polyolefin material bears silane moieties; a catalyst and a foaming system, wherein the provided blend will comprise at least 0.1% by weight of a foaming agent, with respect to the total weight of the polyolefin material; b) extruding a blend, as described in step a), on the conductor to form an insulation layer; c) foaming the insulation layer; and d) crosslinking the insulation layer; a power cable which is obtainable by the process, and use of the power cable.
1. Process for manufacturing a power cable, which power cable comprises at least one core comprising a conductor and an expanded and crosslinked insulation layer surrounding said conductor, wherein said process comprises steps a) to d):
a) providing a blend of:
a polymer composition comprising a polyolefin material, which polyolefin material bears silane moieties,
a catalyst and
a foaming system, wherein the provided blend will comprise at least 0.1% by weight of a foaming agent, with respect to a total weight of the polyolefin material;
b) extruding the blend, as described in step a), on the conductor to form an insulation layer;
c) foaming the insulation layer; and
d) crosslinking the insulation layer.
2. The process according to claim 1 , wherein the foaming system comprises 0.1 to 0.7% by weight of the foaming agent.
3. The process according to claim 1 , wherein the polymer material comprises a low density polyethylene with hydrolysable silane groups.
4. The process according to claim 1 , wherein the polyolefin material comprises 0.001 to 15% by weight of silane compound.
5. A power cable which is defined as in, and is obtainable by the process according to claim 1 .
6. The power cable according to claim 5 , wherein the insulation layer has an expansion degree of 3 to 40%.
7. The power cable according to claim 5 , wherein the insulation layer is in contact with the conductor.
8. The power cable according to claim 5 , which is a low voltage cable or a medium voltage cable.
9. The power cable according to claim 5 , which comprises three cores each comprising a conductor.
10. The power cable according to claim 5 , wherein the insulation layer has an expansion degree of from 5% to 30%.
11. The power cable according to claim 5 , wherein the insulation layer has an expansion degree of from 5% to 25%.
12. The power cable according to claim 5 , wherein the insulation layer has an average cell size equal to or lower than 150 μm.
13. The power cable according to claim 5 , wherein the insulation layer has an average cell size equal to or lower than 100 μm.