Application of Heat Treatment for Coloration and Hairiness Reduction of Wool Yarns

Novel water and dye-free heat treatment method was used to color wool yarn. The heat treatment can not only give the white wool yarn new color but also minimize the yarn hairiness. The influences of heating treatment temperature and time on the wool yarn color were investigated. The microstructure, twist, hairiness, wear resistance, moisture regain and tensile strength of the wool yarn were evaluated to analyze the physical and mechanical properties changes after heat treatment. The results showed that the color strength of wool yarn increased with increasing the heat treatment temperature and time. The hairs equal to or longer than 3 mm reduced significantly after heat treatment. The microstructural structure has no significant change after heat treatment, the unique overlapping scales structure on the surface still observed clearly by the SEM. The tensile strength and wear resistance of wool yarn would decrease with increasing heat treatment temperature and time, and the tensile strength retention was higher than 80% after heat treatment which could meet the requirement in daily applications. Therefore, the heat treatment is an environmentally friendly method to endow wool yarn color and it has a potential in the textile industry.

Automated summary

A novel water and dye-free heat treatment method was used to color wool yarn, which not only gives new color to white wool yarn, but also minimizes yarn hairiness. The color strength of the yarn increased with increasing heat treatment temperature and time, while hairs equal to or longer than 3 mm decreased significantly after heat treatment.