PROCESS FOR DIRECT ON-BOBBIN HEAT TREATING OF HIGH DENIER FILAMENTS OF THERMOTROPIC LIQUID CRYSTALLINE POLYMERS.

摘要

THE PRESENT INVENTION DISCLOSES AND CLAIMS A NOVEL PROCESS FOR THE HEAT TREATMENT OF HIGH DENIER FILAMENTS OF A THERMOTROPIC LIQUID CRYSTALLINE POLYMER. PREFERRED EMBODIMENTS INCLUDE PROCESS FOR THE FORMATION OF HEAT TREATED FILAMENTS OF A FEW WHOLLY AROMATIC POLYESTERS AND POLYESTERAMIDES. THE PROCESS INVOLVES: (A) HEATING OF A 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 RATIO OF GREATER THAN ABOUT 1 AND LESS THAN ABOUT 15 TO FORM A FILAMENT; (C) WINDING THE FILAMENT ON TO A BOBBIN AT A LOW TENSION AND DRAW-DOWN RATIO OF AT LEAST ABOUT 4; AND (D) HEAT TREATING THE FILAMENT DIRECTLY ON THE BOBBIN AT SUITABLE TEMPERATURE AND PRESSURE CONDITIONS FOR A SUFFICIENT PERIOD OF TIME. THE FILAMENTS SO FORMED ARE OF AT LEAST 50 DENIER PER FILAMENT (DPF) AND FEATURE ESSENTIALLY UNIFORM MOLECULAR ORIENTATION ACROSS THE CROSS-SECTION. THE 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.