Abstract: The present invention relates to a sheath (7) for a cable (1), where the sheath contains, at least in part, a halogen-free intumescent composition. The composition of the sheath contains a mixture of a polymer matrix chosen from a polyethylene, a polypropylene, an ethylene copolymer, a propylene copolymer, a silicone, a polyamide, and a mixture thereof and at least one flame-retardant additive. The flame retardant additive has a first inorganic compound having a lamellar crystal structure, and a second inorganic compound inserted between the lamellae of the first compound, where the second compound causes the lamellae to move apart under the application of heat.

Abstract: The present invention provides a composition possessing high resistance to fire propagation, the composition comprising a base polymer and a fireproofing additive containing a metal hydroxide. In the composition, said fireproofing additive further contains a compound based on a carbonate of a metal from group IA of the periodic table of elements coated in a metal salt, said compound constituting at least 10% by weight of fireproofing additive.

Abstract: The present invention relates to a sheath (7) for a cable (1), the sheath comprising, at least in part, a halogen-free intumescent composition, said sheath being characterized in that said composition contains a mixture of:

Abstract: The present invention provides a composition possessing high resistance to fire propagation, the composition comprising a base polymer and a fireproofing additive containing a metal hydroxide. In the composition, said fireproofing additive further contains a compound based on a carbonate of a metal from group IA of the periodic table of elements coated in a metal salt, said compound constituting at least 10% by weight of fireproofing additive.

Abstract: A process for dereticulating a cross-linked polymeric material, such as cross-linked polyethylene from scraps of electric cable coatings or from unused cable coatings through a mechanical mixing cycle, wherein the cross-linked material is subjected to a specific power per mass unit such as to induce shear stresses in the material itself and temperatures higher than pre-established minimum levels. At the end of this cycle the material goes back to a thermoplastic state that may be substantially regarded as thermoplastic; then, following granulation, cooling, drying and sacking, the material will be ready for re-use, either alone or mixed with virgin polymers, according to usual operating technologies for thermoplastic materials. Eventually, the mechanical mixing cycle may be preceeded by a preliminary crushing cycle of the cross-linked polymeric materials to be treated. Preferably, the mixing cycle is carried out in a twin-screw extruder with special screw and temperature profiles.

Abstract: A method of preparing a powder of YBaCuO [phase 123] suitable for forming by drawing-lamination, which includes:preparing a powdered reactive mixture of precursors of purity greater than 99% and with a stoichiometry accurate to within less than 1%,binding this powdered reactive mixture to form intermediate pieces less than two millimeters in thickness which are placed in an oven so that their contact with a support is as small as possible,a heat treating the intermediate pieces,dry grinding the intermediate pieces to obtain grains of said powder with an average diameter of the order of a few .mu.m.

Abstract: A process for obtaining precursors for high critical temperature superconductor ceramics by precipitating salts which are insoluble in water comprises the following stages: A starting solution of soluble salts is prepared in which the cations are in the stoichiometric proportions of the required superconductor phase. A first full precipitation is carried out of a first series of cations at a first value of pH. The first precipitates obtained is filtered out and washed and the filtrate is retained. The pH of the filtrate is changed to a second value and the residual cations are precipitated. The second precipitate is filtered. The first and second precipitates are homogenized. The product obtained is dried, calcined, and ground.