FIELD: processing industry.
SUBSTANCE: used in the manufacturing process of recycling polymer materials for their further use as insulation, sheaths and protective covers of electrical cables. A method for producing a silane-crosslinkable polymer composition based on recycled polyethylene involves processing secondary raw materials based on linear low-density polyethylene (LLDPE), during which the secondary raw materials are crushed to obtain a polymer mass. Next, the polymer mass is washed using a washing liquid, followed by flotation, drying, extrusion and granulation. Moreover, the washing of crushed 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 the polymer mass is extruded at a pressure from 120 to 330 atm and at a temperature from 160 to 230°C, which varies along heating zones distributed along the cylindrical body of the screw extruder as the polymer mass advances, with the number of heating zones from 5 to 15. The polymer mass is extruded with the simultaneous introduction of carbon black concentrate into it, with its further degassing by blowing at atmospheric pressure and again, to remove residual moisture and volatile impurities, by creating a negative pressure from -3 to -2 atm with a vacuum pump, followed by filtration of the resulting polymer composition and granulation. In this case, during the granulation process, a silane mixture containing peroxide and not containing a condensation catalyst is supplied. The resulting polymer composition contains 87–93 wt.% of recycled polyethylene based on LLDPE, 5-10 wt.% of carbon black concentrate, 2-3 wt.% of a silane mixture.
EFFECT: production of an effective polymer composition by processing secondary raw materials for coating cables, which makes it possible to increase their service life.
3 cl, 4 ex, 1 tbl
