High linear density, high modulus, high tenacity yarns and methods for making the yarns

A continuous process for making a para-aramid yarn having a linear density of at least 2666 dtex (2400 denier), a modulus of at least 810 grams per dtex (900 grams per denier) and a tenacity of at least 18 grams per dtex (20 grams per denier), comprising:

• extruding an anisotropic solution of para-aramid in a solvent-through a spinneret having a plurality of holes forming a plurality of fibers,
• passing the fibers through a gas and then a coagulating liquid,
• combining the fibers into a yarn,
• washing the yarn with a washing solution,
• removing some of the washing solution from the surface of the yarn,
• treating the yarn by heating the yarn from 120° C. to 260° C. under a tension of 0.90 to 2.25 grams per dtex (1.00 to 2.50 grams per denier) for a first heating time of 1.6 to 6.0 seconds, and
• after the first treating step, treating the heated yarn from 300° C. to 400° C. under a tension of 2.25 to 4.50 grams per dtex (2.50 to 5.00 grams per denier) for a second heating time of 0.2 to 5.0 seconds,
• cooling the yarn to a temperature of 125 to 170° C.,
• applying a finish on the yarn, and
• winding the yarn on a spool for the first time in the process.