Shredding, Condensation and Compacting: Thermomechanical processing of post-consumer textile polyester

Description

While bottle-to-bottle recycling is an established technology, textile polyester is an underrepresented fraction within closed loop recycling [1]. Before thermomechanical recycling can be attempted, whole garments must be transformed into a processable feedstock shape by steps such as shredding and ejection of foreign materials (such as buttons or zippers). The resulting textile shreds show low density and pourability, which disrupts continuous dosing for extrusion processing [2]; additionally, these physical properties can lead to insufficient drying when using vacuum or dry-air convection ovens. The aim of this work was to improve the quality of post-consumer textile waste to a level suitable for fibre extrusion on a laboratory scale. A three-step process including solid state polycondensation (SSP), pelletisation and drying was applied: 12 hours of vacuum SSP of the shreds results in a homogenous increase of intrinsic viscosity from 0.6 to 0.8, with concurrent dye desorption-degradation. Pelletisation of the resulting material at temperatures above 50°C results in a compressed granule that were dried for processing using conventional methods, resulting in moisture an order of magnitude lower than either fabric or shreds. These pellets can be directly extruded into fibres, avoiding the material degradation of an intermediate melt granulation step.

Period	30 Sept 2024
Event title	PPS 2024 Polymer Processing
Event type	Conference
Location	SpainShow on map