Photochromic Microcapsules for Textile Materials by Spray Drying—Part 3: Application of Photochromic Microcapsules on Cotton Fabrics

Photochromic textiles, a class of functional textiles, have a color build up feature under ultraviolet light irradiation. However, photochromic dye application onto textile materials by conventional finishing techniques has difficulties due to their low water solubility and low affinity to the textile materials. Encapsulation technology could be used to overcome these problems in the production of photochromic textile materials. This article, which is the third in a three-part series, deals with the application of photochromic dye microcapsules produced by a spray drying method onto cotton fabrics. The photochromic dye microcapsules were applied onto cotton fabrics by a pad–dry–cure process. Color build up and ultraviolet transmittance of the resultant photochromic fabrics were evaluated after the application and consecutive washing. Moreover, the fatigue resistance of the photochromic fabrics was studied and the effects of the incorporation of hindered amine light stabilizers into microcapsules were investigated. Ultraviolet protection factor values of the samples were found to be 50+ even after 20 washing cycles. It was shown that the photochromic fabrics have a loss of 10% in ultraviolet protection factor values and 20% in color values after 20 ultraviolet irradiation cycles and the fatigue resistance of the photochromic dye capsules improved with the use of hindered amine light stabilizer compounds during microcapsule production.