Study on the one-bath dyeing of wool/PTT blends (Part I)

Two parts of this paper describe an investigative method for dyeing of blends of polytrimethylene terephthalate (PTT) staple and wool and the tensile properties of the blend fabrics. The dyeing behaviour of Terasil disperse dyes on PTT fibre, their staining on the wool component, and the dyeing behaviour of Lanasol reactive dyes on wool and their staining on the PTT component have been examined. The results have shown that blending PTT staple fibre with wool of similar micron diameters produces improved strength, deformation resistance and tensile elasticity of blends while the soft handle of wool was retained. Most Terasil disperse dyes achieved the highest dye-uptake on PTT staple at 110 degrees C; Terasil dyes and Lanasol dyes showed good compatibility in one-bath dyeing under weak acid conditions at temperatures lower than 120 degrees C. An optimised dyeing technique was developed which minimized the staining problem of Terasil disperse dyes on wool and gave stable union-dyed wool/PTT blended products with higher colour fastness, and lower damage to wool than encountered with normal wool/PET blend dyeing processes.