Polymer composition for w&c application with advantageous electrical properties
AssigneeBorealis AG
InventorsUlf Nilsson, Per-Ola Hagstrand, Villgot Englund, Andreas Farkas, Janis Ritums
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Abstract
The invention relates to a polymer composition with improved DC electrical properties, to the use of the composition for producing a cable layer and to a cable surrounded by at least one layer comprising the polymer composition.
Claims23
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The cable according to claim 15, wherein the crosslinked polymer composition has an electrical conductivity of from 0.05 to 10.0 fS/m, when measured according to DC conductivity method (1) using a 1 mm thick plaque sample as described under “Determination Methods”.
The cable according to claim 15, wherein the amount of the polyethylene (a) is from 1.0 to 30 wt % based on the combined weight of the polyethylene (a) and the LDPE (b).
The cable according to claim 15, wherein the amount of the LDPE (b) is from 70 to 99.0 wt % based on the combined weight of the polyethylene (a) and the LDPE (b).
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The cable according to claim 15, wherein the polyethylene (a) is selected from very low density polyethylene (VLDPE) copolymers, linear low density polyethylene (LLDPE) copolymers, medium density polyethylene (MDPE) copolymer, or high density polyethylene (HDPE) homopolymers or copolymers.
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The cable according to claim 15, wherein the crosslinked polymer composition has a weight fraction of crystals with lamella thickness >10 nm of at least 0.5 wt %, when measured according to DSC method as described in the description part under “Determination Methods”.
The cable according to claim 15, wherein the LDPE (b) is a saturated or unsaturated LDPE homopolymer or a saturated or unsaturated LDPE copolymer of ethylene with one or more comonomer(s).
The cable according to claim 15, wherein the LDPE (b) is an unsaturated LDPE polymer, which is selected from an unsaturated LDPE homopolymer or an unsaturated LDPE copolymer of ethylene with one or more comonomer(s), and wherein the LDPE (b) comprises a total amount of carbon-carbon double bonds/1000 carbon atoms of more than 0.4/1000 carbon atoms.
The cable according to claim 15, wherein the LDPE (b) is an unsaturated LDPE copolymer of ethylene with at least one polyunsaturated comonomer.
The cable according to claim 15, wherein prior to crosslinking the crosslinked polymer composition comprises a polymer composition comprising a peroxide in an amount of from 0.1 to 110 mmol —O—O-/kg polymer composition.
The cable according to claim 15, wherein the inner semiconductive layer comprises a crosslinked first semiconductive composition, the insulation layer comprises a polymer composition consisting of the crosslinked polymer composition, and the outer semiconductive layer comprises a crosslinked second semiconductive composition.
A direct current (DC) power cable comprising a conductor which is surrounded at least by an inner semiconductive layer, an insulation layer and an outer semiconductive layer, in that order, wherein at least the insulation layer comprises a crosslinked polymer composition comprising:
- (a) from 0.1 to 40 wt % of a polyethylene selected from the group consisting of:
- very low density polyethylene (VLDPE) having a density of from 850 to 909 kg/m3, linear low density polyethylene (LLDPE) having a density of from 909 to 930 kg/m3, medium density polyethylene (MDPE) having a density of from 930 to 945 kg/m3, and high density polyethylene (HDPE) having a density of 945 kg/m3 or more;
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- (b) from 60 to 99.9 wt % of a low density polyethylene (LDPE);
- wherein the crosslinked polymer composition has an electrical conductivity of from 0.01 to 20.0 fS/m, when measured according to DC conductivity method (1) using a 1 mm thick plaque sample as described under “Determination Methods.”
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Dependencies are inferred from the claim text.