Effect of the direct introduction of disulfide groups with 2-iminothiolane hydrochloride on wrinkle recovery of natural protein fibers

To develop environmentally friendly natural protein fibers with good wrinkle recovery without changing their excellent physical properties, thiol groups were directly introduced into silk and wool fibers by chemical modification using 2-iminothiolane hydrochloride. Thereafter, disulfide (–SS–) groups were introduced by oxidative cross-linking. The wrinkle recovery of the wool fabrics improved with the increase in 2-iminothiolane hydrochloride concentration. In particular, introducing the reduction process between the 2-iminothiolane hydrochloride treatment and the oxidation process improved the wrinkle recovery of wool fabrics. In contrast, the silk fabrics treated with 0.04 wt% 2-iminothiolane hydrochloride exhibited good wrinkle recovery. In addition, combustion-ion chromatography revealed that sulfur was introduced into the silk fabrics by oxidation after 2-iminothiolane hydrochloride treatment. According to these experiments, directly introducing –SS– groups using 2-iminothiolane hydrochloride into silk and wool fibers effectively improves wrinkle recovery without changing the physical properties of natural protein fabrics.