Processes for forming carbon-containing aramid bicomponent filament yarns

A process for forming a yarn comprising bicomponent filaments, each of the filaments comprising a distinct core of a first aramid polymer comprising 5 to 10 weight percent carbon particles homogeneously dispersed therein, and a distinct sheath of a second aramid polymer being free of discrete carbon particles and having 10 to 20 weight percent of at least one masking pigment homogeneously dispersed therein, with the sheath surrounding the core, the yarn having a total content of 0.5 to 5 weight percent discrete carbon particles;

• the process comprising the steps of:
• a) forming a first polymer solution containing the first aramid polymer in a solvent, the aramid polymer further comprising discrete carbon particles, and forming a second aramid polymer solution of the second aramid polymer being free of carbon particles and having at least one masking pigment in the same or different solvent;
• b) providing a spinneret assembly having separate inlets for the first aramid polymer solution and the second aramid polymer solution and a plurality of exit capillaries for spinning dope filaments;
• c) forming a plurality of dope filaments having a sheath of the second aramid polymer solution and a core of the first aramid polymer solution by extruding through the exit capillaries a plurality of conjoined streams of the first and the second aramid solutions into a spin cell, and
• d) extracting solvent from the plurality of dope filaments to make a yarn of polymer filaments.