Polymer Filament
Continuous synthetic yarn produced from post-consumer PET bottles offers a lower carbon footprint than virgin petroleum-based materials. This product, known as recycled filament polyester, behaves almost identically to virgin polyester during texturizing and weaving. Brands use it to meet sustainability targets in sportswear and bag fabric production.
The scope of this definition is limited to extruded continuous filaments rather than spun staple fibers.
Extrusion Process
Melting washed bottle flakes and filtering the polymer melt precedes extrusion through spin packs to create clean continuous yarn. During this extrusion of recycled filament polyester, fine filters catch any residual contaminants to prevent filament breaks. The filtered polymer is then drawn and texturized to give the yarn bulk and elasticity.
This continuous mechanical handling ensures that the finished yarn achieves high tensile strength.
Dyeing Behavior
Slight variations in polymer purity can cause uneven dye uptake if the recycled flakes are not sorted properly by color and type. Processing recycled filament polyester requires careful temperature monitoring during high-pressure dyeing to ensure color uniformity. Dyers adjust the dye recipes to compensate for any slight discoloration in the raw polymer.
Consistent chemical monitoring prevents color variance across different dye lots.
Quality Limit
Frequent filter changes are required due to trace contaminants, increasing the production cost of fine-denier yarns. For this reason, very fine yarns are rarely produced from recycled polymer.
