Improving the Fastness Properties of Thermochromic Leathers: The Effects of UV Absorbent and Cross-Linkers

The emerging new applications of thermochromic pigments in leather industry could give a promising opportunity to create innovative designs of smart thermochromic leathers and these leathers are well known with their colour changing effect depending on thermal activation temperature of the thermochromic pigments. A long product life is also needed for thermochromic leathers due to the demand for additive use which will enhance the fastness properties of the microencapsulated thermochromic pigments. This study aimed at increasing the light and rubbing fastness values of the leathers that change colour with temperature. Touch (magenta; 31 degrees C) and cold (blue; 15 degrees C) activated two thermochromic pigments were used in order to provide the colour change of the finished leathers. UV absorbent and cross-linking chemical additives were used along with thermochromic pigments in the finishing procedure to increase the fastness properties of the leathers. Colour change features, rubbing and light fastness properties of thermochromic leathers were analysed by a spectrophotometric method in addition to ISO standards of related fastness properties. The use of a UV absorbent in the finishing procedure lead to an increase in the light fastness values of touch and cold activated thermochromic leathers. Likewise, it was revealed that the use of cross-linker in the top coat of finishing process improved the rubbing fastness properties of thermochromic leathers