Method of dyeing a substrate comprising elastomeric fibre and non-elastomeric fibre, and a dyed subtrate comprising these fibres

Abstract

A dyeing method comprising a) dyeing a substrate containing (i) elastomeric fiber containing at least 30 wt. % of a first polymer having a glass transition temperature T1 of less than 60° C. and (ii) non-elastomeric companion fiber containing more than 50 wt. % of a second polymer, said second polymer being polymer having no glass transition temperature or polymer having a glass transition temperature T2 that is at least 20° C. higher than T1, b) contacting the pre-dyed substrate with an extraction medium at a temperature Te and a pressure Pe, said extraction medium comprising at least 50 wt. % of supercritical or liquefied carbon dioxide; wherein Te exceeds Tg1,extraction and wherein Te is less than Tg2,extraction in case the companion 1 fiber contains more than 50 wt. % of polymers having a glass transition temperature T2; Tg1,extraction representing the glass transition temperature of the first polymer in carbon dioxide at pressure Pe; and Tg2,extraction representing the glass transition temperature of the second polymer in carbon dioxide at pressure Pe.