Filament Sticking

Two or more adjacent individual filaments stick together and merge, forming a merged yarn with reduced filament count and increased fineness. Stuck filaments cannot be separated into independent individual filaments when the yarn bundle is spread, seriously affecting the final use performance of the fiber — stuck filaments in textiles cause thick streaks on the fabric surface, and stuck filaments in spunbond nonwovens destroy the fabric surface uniformity. The root cause of filament sticking lies in too small spinneret hole spacing or insufficient cooling separation.

1. Mold/tooling factor: the spinneret hole spacing is too small or the spinneret face temperature is high. 2. Cooling/environmental factor: insufficient cooling air volume or wind speed causes the filaments to be unable to fully separate. 3. Material/formulation factor: the bundling effect of the oil agent on the yarn bundle is too strong. 4. Mold/tooling factor: excessive expansion ratio during extrusion from the spinneret holes causes adjacent filaments to contact.

1. Process parameter optimization and adjustment: appropriately adjust the spinneret hole spacing. 2. Mold/tooling improvement and maintenance: increase the cooling air volume. 3. Equipment inspection and system maintenance: adjust the oil agent concentration so that it does not produce excessive cohesion. 4. Material/formulation optimization: optimize the geometric design of the spinneret hole outlets. 6. Preventive management: establish standardized process parameter cards and quality control limits for each mold/product, and regularly conduct process capability index (CPK) evaluations. For recurring problems, use fishbone diagrams or the 5Why analysis method to trace the root cause, and solidify the countermeasures as PFMEA control points. Establish a regular equipment maintenance system, and implement life management for key tooling such as dies/spinnerets/calender rolls/coating heads.

The essence of filament sticking is that adjacent individual filaments fail to be fully cooled and separated after exiting the spinneret holes. The core of the solution is "increasing spacing + strengthening cooling + adjusting oil agent": appropriately increase the spinneret hole spacing to reduce the chance of inter-filament contact, increase the cooling air volume to accelerate solidification and separation, and adjust the oil agent concentration to avoid excessive bundling effect.