A cable comprising one or more conductors surrounded by at least an inner semiconductive layer, an insulation layer and an outer semiconductive layer, in that order, wherein said insulation layer comprises an LDPE homopolymer or copolymer having a density of 927 to 940 kg/m.sup.3 and wherein the conductivity of the LDPE is 5.0 fS/m or less when measured according to DC conductivity method as described under Determination Methods.

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.

The present disclosure relates to methods of making an article comprising PTFE, methods of making expanded articles comprising PTFE, articles comprising PTFE, and expanded articles comprising PTFE having improved mechanical and electrical performance and particularly reduced variability in mechanical, electrical and dimensional properties, particularly over long lengths.

An extruder (5) for extruding an electric cable has an extrusion screw (7) arranged inside a barrel (6) and making it possible for the polymer to melt gradually in order to form an extrusion composition and for this composition to be transported along the extrusion screw (7). An extrusion head (8) is arranged at a distal end (21) of the extrusion screw (7) and configured to apply the composition around an elongated electrically conductive element. The at least one liquid injection channel (22) is formed through the barrel (6), the at least one injection channel (22) having at least one outlet orifice (30) emerging in a zone of the extrusion screw (7) in which the thermoplastic polymer is at least partially in the solid state.

An extruder (5) for extruding an electric cable includes at least one elongated electrically conductive element and at least one extruded thermoplastic layer surrounding said elongated electrically conductive element. The extruder has a member (4) for feeding a polymer in solid form, a barrel (6) fed by the feed member, and an extrusion screw (7) arranged inside the barrel (6) and making it possible for the polymer to melt gradually to form an extrusion composition and for this composition to be transported along the extrusion screw (7) to a distal end (21) of the extrusion screw (7). The extrusion screw (7) extends along a longitudinal axis (A). The extrusion screw has a barrier zone having at least two threads with an extrusion head (8) arranged at a distal end (21) of the extrusion screw (7) and configured to apply the composition around an elongated electrically conductive element. At least one liquid injection channel (22) is formed in the extrusion screw (7). The at least one injection channel (22) emerging inside the barrel (7) level, with at least one outlet orifice (30) formed on an outer surface of the extrusion screw (7).

A method for manufacturing an electric cable includes a step of mixing an extrusion composition having at least one thermoplastic polymer in the form of solid particles, a dielectric liquid and at least one nanofiller, a step of introducing the extrusion composition into a feed zone of a barrier screw which zone is situated at the inlet of the extruder, and a step of applying the extrusion composition coming from the prior step around an elongate electrically conducting element at the head of the extruder. The mixing step includes a step of premixing the dielectric liquid with the at least one nanofiller to obtain an intermediate composition which is then mixed with the at least one thermoplastic polymer in order to obtain the extrusion composition.

In an electrical cable of the type having an outer sheath enclosing a conductor assembly comprising a plurality of insulated conductors disposed within a binder, the binder having a crush resistance for protecting the insulated conductors, an improvement in which a strength enhancer is applied such that the binder can be removed without decreasing a crush resistance of the electrical cable.

In one aspect, a foamable composition is disclosed, which comprises a base polymer, talc and a citrate compound blended with the base polymer. In some embodiments, the concentration of the talc in the composition is in a range of about 0.05% to about 25% by weight, e.g., in a range of about 2% to about 20%, or in a range of about 3% to about 15%, or in a range of about 5% to about 10%. Further, the concentration of the citrate compound in the composition can be, for example, in a range of about 0.05% to about 3% by weight, or in a range of about 0.02% to about 0.9% by weight, or in a range of about 0.03% to about 0.8% by weight, or in a range of about 0.04% to about 0.7% by weight, or in a range of about 0.05% to about 0.6% by weight

An assembly and a method for manufacturing an insulation layer of an electrical conductor are presented. The electrical conductor is enclosed in a cavity of a mold. Spacers embedded into holes of the mold are movable into the cavity for holding the electrical conductor in the cavity to maintain a gap between the electrical conductor and surface of the cavity. Distance of the gap is defined by thickness of the insulation layer. Spacers are movable into the holes of the mold from the cavity to maintain even surface of the cavity. Insulation compound fills entire gap and is cured to form the insulation layer having homogenous thickness.

A semiconductive polymer composition comprising: (a) an ethylene alkyl (meth) acrylate copolymer; (b) 15 to 48 wt % carbon black having an iodine adsorption number of 85 to 140 mg/g (ASTM D 1510-19a), an oil absorption number of 90 to 110 ml/100 g (ASTM D 2414-19) and an average primary particle size of 29 nm or less (ASTM D 3849-14a); and (c) 0.05 to 2.0 wt % of 4,4-bis(1,1-dimethylbenzyl)diphenylamine; all weight percentages being based on the total weight of the semiconductive polymer composition.