The Effect of Dye Particles on the Rub Fastness of Naphthol Dyes

The effect of dye particles on the rub fastness of naphthol dyes has been investigated form the kinetic viewpoint. A measure of the rub fastness properties can be given by the rate constant and/or the equilibrium constant of a reversible first-order reaction. The presence of granular dye particles increases these constants and lowers the rub fastness. On the other hand, needle-shaped dye particles have little effect on these constants and do not lower the rub fastness