Abstract

Thermochromic dyes and pigments offer significant potential for functional and aesthetic design of smart textile materials and in the area of the leather industry potential application of thermochromic pigment dispersions opens up a new issue. In this study, thermochromic pigments were applied in the leather finishing process in order to obtain leathers changing colour with temperature and their potential for innovative design concepts accompanied with an evaluation of technical features of the materials is presented. Two thermochromic pigments, providing colour change at 15°C and 31°C were applied at different proportions in the base coat of the finishing process. The colour measurements and colour change of the thermochromic leathers were determined by a Minolta CM-3600d spectrophotometer both prior to and subsequent to the rubbing fastness tests.

To and fro rubbing, crockmeter and light fastness properties of leathers were examined according to TS EN ISO 11640, ASTM D5053 and ISO 105-B02 standards respectively. Leathers coloured with thermochromic pigments showed a significant colour changing effect depending on temperature and, as expected, the thermochromic effect was improved by a higher thermochromic pigment proportion in the finishing formulation. Fastness properties of thermochromic leathers, except light fastness, were found to be adequate compared to conventionally finished leathers. The findings suggest that the thermochromic pigments could be alternatively used with conventional pigments in leather finishing applications according to leather fashion trends and different designs of leather products in addition to technical leathers and textiles in the field of medical and protective wear applications.