Polymer blend composition for wire and cable applications with advantageous electrical properties
AssigneeBorealis AG
InventorsPer-Ola HAGSTRAND, Thomas GKOURMPIS
Life of this patent
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Abstract
The invention provides a polymer composition comprising a low density polyethylene (LDPE); polypropylene (PP) and a compatibiliser. The invention also relates to cables comprising said polymer composition and the use of the polymer composition in the manufacture of an insulation layer of cable.
Claims23
1-17. (canceled)
A power cable comprising one or more conductors surrounded by at least an insulation layer, wherein said insulation layer comprises a polymer composition comprising:
- a) a low density polyethylene (LDPE);
- b) polypropylene (PP) and;
- c) a compatibilizer selected from a linear low density polyethylene (LLDPE).
The power cable as claimed in claim 1, wherein the conductivity of the polymer composition is 40 fS/m or less, when measured at 30 kV/mm according to DC conductivity method as described under “Determination Methods”.
The power cable as claimed in claim 1, wherein the conductivity of the polymer composition is 70 fS/m or less, when measured at 45 kV/mm according to DC conductivity method as described under “Determination Methods”.
The power cable as claimed in claim 1, wherein the conductivity of the polymer composition is 80 fS/m or less, when measured at 60 kV/mm according to DC conductivity method as described under “Determination Methods”.
The power cable as claimed in claim 1, wherein the conductivity of the polymer composition is at least 10% lower than the conductivity of an otherwise identical polymer composition comprising neither the PP nor the compatibilizer, when measured according to DC conductivity method as described under “Determination Methods” at an electrical stress which is 30 kV/mm or more.
The power cable as claimed in claim 1, wherein the LDPE is an LDPE homopolymer or a LDPE copolymer with at least one non-polar comonomer.
The power cable as claimed in claim 1, wherein the PP is a propylene copolymer with one or more comonomers.
The power cable as claimed in claim 1, wherein:
- the LDPE is present in an amount of at least 55 wt % relative to the total weight of the polymer composition as a whole.
The power cable as claimed in claim 1, wherein the PP b) is present in an amount of from 0.01 to 40 wt % relative to the total weight of the polymer composition as a whole.
The power cable as claimed in claim 1, wherein the compatibilizer c) is present in an amount of from 0.01 to 10 wt % relative to the total weight of the polymer composition as a whole.
The power cable as claimed in claim 1, wherein:
- the PP is a random copolymer of propylene or a heterophasic copolymer of propylene.
The power cable as claimed in claim 1, wherein the PP is a heterophasic copolymer comprising a propylene random copolymer as a matrix phase (RAHECO) or a heterophasic copolymer having a propylene homopolymer as a matrix phase (HECO).
The power cable as claimed in claim 1, wherein the compatibilizer is a multimodal LLDPE.
The power cable as claimed in claim 1, wherein the melting point (DMTA) of the polymer composition, which is defined as the temperature where the storage shear modulus, G′, is 2 MPa, is at least 118° C.
The power cable as claimed in claim 1, wherein the polymer composition is non crosslinked.
The power cable as claimed in claim 15, wherein the non-crosslinked polymer composition comprises:
- a) at least 55 wt % of the LDPE, wherein the LDPE is a low density polyethylene (LDPE) homopolymer or an LDPE copolymer with a non polar comonomer;
- b) 1.0 to 40 wt % of the PP, wherein the PP is a polypropylene copolymer (PP) and;
- c) 0.25 to 10 wt % of the compatibilizer.
The power cable as claimed in claim 15, wherein the non-crosslinked polymer composition comprises:
- a) at least 55 wt % of the LDPE, wherein the LDPE is a low density polyethylene (LDPE) homopolymer or an LDPE copolymer with a non polar comonomer;
- b) 1.0 to 30 wt % of the PP, wherein the PP is a polypropylene copolymer (PP) and;
- c) 0.25 to 5.0 wt % of the compatibilizer
The power cable as claimed in claim 15, wherein the non-crosslinked polymer composition comprises:
- a) at least 55 wt % of the LDPE, wherein the LDPE is a low density polyethylene (LDPE) homopolymer;
- b) 1.0 to 40 wt % of the PP, wherein the PP is a polypropylene copolymer (PP) and;
- c) 0.25 to 10 wt % of the compatibilizer.
The power cable as claimed in claim 15, wherein the non-crosslinked polymer composition comprises:
- a) at least 55 wt % of the LDPE, wherein the LDPE is a low density polyethylene (LDPE) homopolymer;
- b) 1 to 40 wt % of the PP, wherein the PP is a heterophasic polypropylene copolymer or random heterophasic polypropylene copolymer (PP) and;
- c) 0.25 to 10 wt % of the compatibilizer.
A process for producing the power cable as claimed in claim 1, comprising the step of:
- applying on a conductor at least an insulation layer comprising a polymer composition comprising:
- a) a low density polyethylene (LDPE);
- b) polypropylene (PP) and;
- c) a compatibilizer selected from a linear low density polyethylene (LLDPE).
A power cable comprising one or more conductors surrounded by at least an insulation layer, wherein said insulation layer comprises a thermoplastic polymer composition comprising:
- a) a low density polyethylene (LDPE);
- b) polypropylene (PP) and;
- c) a compatibilizer selected from a linear low density polyethylene (LLDPE) or an olefin block copolymer.
Dependencies are inferred from the claim text.