COMPOSITE CONDUCTING THREAD Russian patent published in 2001 - IPC

FIELD: conducting materials. SUBSTANCE: invention relates to manufacturing composite conducting threads and resistive layers including these threads, which are employed for fabrication of various-destination flexible and rigid heating elements. Thread is formed by two fibrogenic polymers arranged relative to each other as "shell" and "nucleus", the latter being made from polycaproamide fibers and the former consisting of fiber-forming fluorine-containing polyolefin, preferably tetrafluoroethylene/vinylidene fluoride copolymer filled with furnace carbon black at weight ratio from 1:0.6 to 1: 0.8. Outside and inside surfaces of shell bear continuous framework composed of carbon black particles dispersed to fraction 0.5-1.0 mcm. Weight ratio of nucleus to shell is 1:(0.7-0.8) and linear density of thread equals 52-58 tex. When manufacturing thread, acetone spinning solution is first prepared in dissolver from fluorine-containing polyolefin. Solution is filtered on frame filter press and predetermined amount of furnace carbon black is added. To disperse carbon black particles to fraction 0.5-1.0 mcm, resulting suspension is treated on rotor-pulse mixer involving high- frequency pulsation of intensive hydrodynamic flow at 20-25 C, rotor rotation speed 700-1400 rpm, and pressure 0.8-1.0 kg/sq.cm, after which following operations are fulfilled: evacuation, formation of integrated "nucleus-shell" thread in filament extrusion device with die hole diameter 0.9-1.1 mm, and removal of solvent in drying section at 125-128 C and thread drawing velocity 35-40 m/min. EFFECT: increased reliability and working ability of thread. 3 cl, 8 dwg, 2 tbl, 5 ex