FIELD: recycling.
SUBSTANCE: group of inventions relates to the recycling industry; it can be used in a technological process of recycling of polymer materials for their further use by application of insulation, shells, and protective covers of cables. A method for recycling of polyethylene-based secondary raw materials includes grinding of source secondary polyethylene raw materials to obtain polymer mass with its further washing, using washing liquid, flotation, drying, extrusion, and granulation. Polymer mass includes high-pressure low-density polyethylene (hereinafter – LDPE) with a degree of contamination up to 30% and high-pressure linear low-density polyethylene (hereinafter – LLDPE). Amount of LDPE exceeds LLDPE by at least 2.4 times and no more than 11.2 times. Washing of ground polymer raw materials is carried out with water at a temperature from 14 to 60°C. After flotation and drying, homogenization and agglomeration are carried out. Then, polymer mass is extruded at pressure from 120 to 330 atm and at a temperature from 160 to 230°C, which varies according to heating zones distributed along a cylindrical case of a screw extruder along a course of movement of polymer mass. A number of heating zones ranges from 5 to 15. Further, extrusion of polymer mass is carried out with simultaneous introduction of a light and heat stabilizer and an additive – carbon black, with its further degassing by blowing at atmospheric pressure and repeatedly, to remove residual moisture and volatile impurities, by creation of negative pressure from -3 to -2 atm with a vacuum pump, followed by filtration of the resulting polymer composition and granulation. The polymer composition for creation of a protective cable shell, made by this method, contains from 65 to 89.9 wt.% of LDPE, from 8 to 27 wt.% of LLDPE, from 2 to 8 wt.% of carbon black concentrate, from 0.1 to 0.5 wt.% of the light and heat stabilizer.
EFFECT: obtainment of an effective polymer composition during recycling of secondary raw materials for covering cables, allowing for an increase in their service life.
10 cl, 1 tbl
