Influence of the dye transfer inhibitors for the washing of softened cotton fabric

Abstract

In this, work the performance of several dye transfer inhibitors (DTI) copolymers (PVP, PVNO and PVNO with PVP) was tested for use as DTIs in washing softened undyed cotton fabric, in the presence of a direct dye in the washing bath, with and without water hardness. Three direct dyes were tested: red, blue and yellow. The detergent used was composed of an LAS anionic surfactant and a non-ionic fatty alcohol ethoxylate surfactant with 7 m. OE, both separately and in the different molar proportions anionic with non ionic, at a total concentration of 5 × 10⁻³ M, and in the presence of zeolite as a builder. Washing temperature was 40°C and washing time was 30 min. Staining of the softened undyed cotton fabric was assessed as the CIELAB colour differences between the original fabric and the stained fabric after washing.The different DTIs and the dye in the washing bath with and without water hardness were tested.

Keywords:

• dye transfer inhibitors (DTI)
• softened cotton
• surfactants
• LAS
• alcohol ethoxylate (AE)

Acknowledgements

Thanks to Mercedes Simó Cima for her assistance in the experimental part of this work. Likewise, thanks to ISP International Speciality Products, New Jersey (USA), for supplying the DTI polymers, available on the market in Spain, and to Croda for supplying the non-ionic surfactant Synperonic A7 (AE-7), and to Dystar for the samples of the direct dyes tested.