Process for making poly(trimethylene terephthalate) bulked continuous filaments

A process for the production of poly(trimethylene terephthalate) bulked continuous filaments comprising the steps of:

• a) extruding molten poly(trimethylene terephthalate) polymer at a temperature from 245.degree. C. to 285.degree. C. through a spinneret to form filaments, said poly(trimethylene terephthalate) polymer having an intrinsic viscosity in the range of 0.6 to 1.3 and a water content of less than 100 ppm by weight;
• b) cooling the filaments in a quench chimney by means of air flowing perpendicularly to the filaments at a velocity in the range of 0.2 to 0.8 m/sec.;
• c) coating the filaments with a spin finish;
• d) heating the filaments to a temperature greater than the glass transition temperature of the filaments, but less than 200.degree. C. prior to drawing the filaments;
• e) drawing the filaments between a set of feed rolls and a set of draw rolls to a draw ratio high enough that the break elongation of the drawn filaments is between 10 to 90%, the temperature of the draw rolls being from 120.degree. to 200.degree. C.;
• f) feeding the drawn filaments from the draw rolls at a speed of at least 800 m/min. to a hot-fluid jet bulking unit in which the filaments are blown and deformed in three dimensions with hot bulking fluid having a temperature at least as high as that of the draw rolls to form bulked continuous filaments having random 3-dimensional curvilinear crimp;
• g) cooling the bulked continuous filaments to a temperature less than the glass transition temperature of the filaments;
• h) winding up the filaments at a speed at least 10% lower than that of the draw rolls.