초록 ▼

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

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.

대표청구항 ▼

[ What is claimed is:] [1.] A process for the recycling of a cross-linked thermoplastic polythenes polymeric material coming from machining scraps of electric cable coating materials, characterized in that it comprises a mechanical mixing cycle of said cross-linked thermoplastic polythenes polymeric

[ What is claimed is:] [1.] A process for the recycling of a cross-linked thermoplastic polythenes polymeric material coming from machining scraps of electric cable coating materials, characterized in that it comprises a mechanical mixing cycle of said cross-linked thermoplastic polythenes polymeric material carried out in an extruder-mixer having a feed zone, at least one mixing zone and an extrusion head, during which said cross-linked thermoplastic polythenes polymeric material is submitted for a pre-established time to a mechanical mixing action and to shear stresses higher than a pre-established value in the range of 50 to 150 S.sup.-1, and wherein the extruder-mixer is heated so as to have an increasing temperature profile from its feed zone to its extrusion head, such as to cause dereticulation of said material.