Process for the production of a multipolar cable, and multipolar cable produced therefrom

A multipolar cable comprising a plurality of cores, each core comprising at least one conductive element and at least one layer of electrical insulation in a position radially external to said at least one conductive element, said cores being twisted together so as to form an assembled element providing with a plurality of interstitial zones between said cores, said interstitial zones being filled with an expanded polymeric material to form a filling layer, said expanded polymeric layer being co-extruded with at least one containment layer of a polymeric material located in a position radially external to said filling layer;

• wherein:
• said cable further comprises at least one additional layer of expandable polymeric material in a position radially external to said containment layer;
• and
• wherein said expandable polymeric material of said filling layer, said polymeric material of said containment layer, and said expandable polymeric material of said further layer located in a position radially external to said containment layer are independently chosen from:
• a) ethylene copolymers with an ethylenically unsaturated ester in which the quantity of unsaturated ester is between 5% and 80% by weight;
• b) elastomeric copolymers of ethylene with at least one C3-C12 α-olefin, and optionally a diene, having the following composition:
• 35-90 mol % ethylene, 10-65 mol % α-olefin, and 0-10 mol % diene;
• c) copolymers of ethylene with at least one C4-C12 α-olefin, and optionally a diene, having a density between 0.86 and 0.90 g/cm3;
• and
• d) propylene modified with ethylene/C3-C12 α-olefin copolymers, wherein the ratio by weight between polypropylene and the ethylene/C3-C12 α-olefin copolymer is between 90/10 and 30/70.