PROCESS FOR MAKING HIGH DENIER FILAMENTS OF THERMOTROPIC LIQUID CRYSTALLINE POLYMERS AND COMPOSITIONS THEREOF

THE PRESENT INVENTION DISCLOSES AND CLAIMS A NOVEL PROCESS FOR THE FORMATION OF HIGH DENIER AS-SPUN AND HEAT-TREATED FILAMENTS OF A THERMOTROPIC LIQUID CRYSTALLINE POLYMER. PREFERRED EMBODIMENTS INCLUDE PROCESS FOR THE FORMATION OF AS-SPUN AND HEAT TREATED MONOFILAMENTS OF A FEW WHOLLY AROMATIC POLYESTERS AND POLYESTERAMIDES. THE PROCESS INVOLVES (A) HEATING OF THERMOTROPIC LIQUID CRYSTALLINE POLYMER TO ABOVE ITS MELTING TRANSITION TEMPERATURE; (B) PASSING SAID MOLTEN POLYMER THROUGH AN EXTRUSION CHAMBER EQUIPPED WITH AN EXTRUSION CAPILLARY OF AN ASPECT RATION OF GREATER THAN ABOUT 1 AND LESS THAN ABOUT 15 TO FORM A FILAMENT; AND (C) WINDING THE FILAMENT AT A DRAW-DOWN RATIO OF AT LEAST ABOUT 4. THE FILAMENTS SO FOMLED ARE OF AT LEAST 50 DENIER PER FILAMENT (DPF) AND FEATURE ESSENTIALLY UNIFORM MOLECULAR ORIENTATION ACROSS THE CROSS-SECTION. IN A FINAL OPTIONAL STEP, THE FILAMENTS ARE HEAT TREATED IN STAGES TO FORM FILAMENTS EXHIBITING EXCELLENT TENSILE PROPERTIES. BOTH AS-SPUN AND HEAT-TREATED FILAMENTS FEATURE REMARKABLY GOOD TENSILE PROPERTIES RETAINING AT LEAST 80 TO 90 PERCENT OF THE PROPERTIES EXPECTED OF CONVENTIONAL LOW DENIER (5 TO 10 DPF) FILAMENTS.