The Dyeing of Shrink‐resistant Wool

The effects of boiling aqueous solutions on wool oxidised with a variety of reagents have been studied. Strength and weight losses for oxidised wool (as for untreated wool) were at a minimum at pH 3–. Wool that had been treated with hydrogen peroxide to oxidise about 7% cystine was damaged no more than untreated wool in the boiling solutions, but wool treated with shrink‐resist agents (acid chlorine, permonosulphuric acid–sulphite, permanganate–salt) was damaged more severely than untreated wool. This increased susceptibility to damage is probably due to attack by the shrink‐resist agents on the cuticle of the fibres and therefore is an inherent feature of wool made shrink‐resistant by oxidative treatments in aqueous solution. Investigations on the dyeing of shrink‐resistant wool with milling acid and 1:2 metal‐complex dyes are reported. Strength and weight losses were minimised by dyeing at pH near 4 in the presence of non‐ionic dyeing assistants and by keeping the temperature to which the bath was ultimately brought to the minimum required forexhaustion and thorough penetration of the dyes into the fibres, usually about 85–90°C.