Patent ID: 7776246

Claim:
A continuous process for making a polyareneazole multifilament yarn comprising: a) extruding a solution comprising polyareneazole polymer and polyphosphoric acid through a plurality of orifices to produce dope filaments; b) passing the dope filaments of step (a) through an air gap and then through a coagulation bath to convert the dope filaments to substantially solid polymer filaments and form a multifilament yarn from said substantially solid polymer filaments; c) hydrolyzing in a separate step at least some of the polyphosphoric acid in the substantially solid polymer filaments in the yarn by heating the yarn of step (b) to a temperature above about 150° C. for up to about two minutes; d) washing at least some of the hydrolyzed polyphosphoric acid from the yarn of step (c); e) drying the washed yarn of step (d); f) optionally, heating the yarn above about 300° C., and g) collecting the yarn at a speed of at least about 50 meters per minute.