Setting of Specialty and Natural Blend Yarns
topic
Heat setting of wool, wool-synthetic blends, and specialty protein fibre yarns uses lower steam temperatures of 80 to 110 degrees Celsius with moisture-saturated conditions that set the wool fibre hydrogen bonds and disulphide bonds in relaxed configuration without the higher temperatures used for synthetic fibres, with wool setting chemistry involving cystine bond rearrangement that is irreversible above a threshold temperature requiring careful temperature control to avoid fibre damage.
Role
Stabilises the structure of wool and blended yarns through the thermal and chemical setting mechanisms specific to protein fibre chemistry that differ fundamentally from the crystallisation-based setting of synthetic polymers, requiring adapted setting conditions for each fibre blend composition that balance adequate stress relaxation for dimensional stability against thermal damage to the most heat-sensitive blend component.