Using Nano-pigment for Coloration of Leather

Mainly leather is dyed using anionic dyestuffs such as acid, direct and metal complex dyes, but the use of pigments is not common for leather dyeing. Dye penetration into the inner layers of the leather is a difficult task due to 3D infrastructure of leather. In the present study, an attempt has been made to improve the exhaustion of nano-pigment in dyeing leather by using ultrasound. Optimum dyeing conditions including reduced dyeing time is aimed. Taguchi method was employed for the design of experiments. CIELAB color coordinates reflectance values of dyed leathers were evaluated using a reflectance spectrophotometer. The K/S values of the samples were considered to be proportional to the absorption of nano-pigment into the leather. The optimum level of the effective parameters namely as: wetting time, type of swelling agent, ultrasonic bath time, and amount of pigment were evaluated and confirmed by complementary experiments.