Cable with impact-resistant coating

摘要

A power transmission cable comprises: (a) a conductor; (b) layer(s) of compact insulating coating placed around conductor (a); and (c) a coating of expanded polymer material placed around the coating (b). The polymer material has predetermined mechanical strength properties and a predetermined degree of expansion so as to impart impact-resistant properties to the cable. Also claimed are (I) a method for imparting impact strength to a power transmission cable; (II) use of an expanded polymer material for imparting impact strength to a power transmission cable; and (III) a method for evaluating the impact strength of a cable. Preferably the coating is obtained from a polymer material that, before expansion, has a flexural modulus at room temperature (ASTM D790) of at least 200 MPa (600-1500 MPa). Degree of expansion of the polymer material is 20-3000% (50-200%). Coating thickness is 0.5 mm (2-4 mm). Expanded polymer material is a polyolefin or copolymer based on PE and/or PP modified with E-P rubber (EPR). PP is modified with EPR in the weight ratio (PP/EPR) 90/10-50/50 (70/30). Polyolefin (co)polymer contains a predetermined amount (10-60%wt.) of vulcanized rubber in powder form. Cable comprises an outer polymer sheath in contact with the expanded polymer coating. The sheath has a thickness of 1-5 mm.