Polyamide yarn process
View Patent ↗A process for making a synthetic melt spun polyamide filament in a solid phase polycondensation apparatus is disclosed. The flow rate of the purge (make-up) gas to the apparatus is increased, and the overall pressure in the apparatus is decreased, as compared to solid phase polycondensation apparatus of the prior art. As a result, the removal of the thermal degradation impurity from the polymer flake contributes to improving the yarn quality and at the same time, extends the spinneret wipe life.
1. A process for making a synthetic melt spun polyamide filament comprising the steps of:
supplying polyamide polymer with an RV of 36 to 38 to a solid phase polycondensation apparatus;
humidifying a purge gas with water vapor;
supplying said purge gas to the solid phase polycondensation apparatus at a flow rate in the range of about 2 to about 3 kg/hour per kg of polymer per hour;
treating the polyamide polymer in the solid phase polycondensation apparatus with the purge gas at a solid phase polycondensation system pressure of about 110 to about 120 kPascal;
conveying the treated polyamide polymer to a melt extrusion apparatus;
melting the polyamide polymer in the melt extrusion apparatus;
extruding the melted polyamide polymer through a spinneret plate; and
forming at least one continuous filament of polyamide polymer with a yarn RV of about 51 to about 54.
2. The process of claim 1 , further including quenching and cooling the filament.
3. The process of claim 2 , further including post-treating the filament and winding up the filament.
4. The process of claim 3 , further including wiping the spinneret plate on the capillary exit side, in cycles, wherein each wiping cycle is separated by about 8 to about 12 hours.
5. The process of claim 1 wherein the purge gas is comprised of nitrogen gas supplied at a flow rate in the range of about 2 to about 3 kg/hour per kg of polymer per hour.
6. A process for making a synthetic melt spun polyamide filament comprising the steps of:
supplying polyamide polymer with an RV of 36 to 38 to a solid phase polycondensation apparatus;
treating a nitrogen comprising purge gas with water vapor,
supplying said purge gas to the solid phase polycondensation apparatus at a flow rate in the range of about 2 to about 3 kg/hour per kg of polymer per hour;
treating the polyamide polymer in the solid phase polycondensation apparatus with the purge gas at a solid phase polycondensation system pressure of about 110 to about 120 kPascal;
conveying the treated polyamide polymer to a melt extrusion apparatus;
melting the polyamide polymer in the melt extrusion apparatus;
extruding the melted polyamide polymer through a spinneret plate; and
forming at least one continuous filament of polyamide polymer with a yarn RV of about 51 to about 54.