STUDIES ON THE DYEING OF ACRYLONTRILE FIBRE

The retarding effect of surface active agents on absorption of acid dye with cuprous ion technique is discussed in relation to the rate of dyeing, and is analysed particularly from the viewpoint of the modern theory of diffusion into fibre.Anionic auxiliary agents, which are expected to have an affinity between the fibres, act so as to retard the absorption of dye, in proportion to the concentration in the bath, and serve the purpose of obtaining more even dyeing. The retarding action of nonionic auxiliary agents is found, to a certain extent, to depend upon their concentration. Even a small addition, less than 1% on the weight of fibre, to a dyebath are usually regarded as unwise, as it promotes the absorption of dye. However, since there appeares retarding action at 2.5 and 5%, it seems they react with dye. In each case, surface active agents react upon positively charged fiber that produced cuprous ion co-ordinated with nitrile group. It shows closely analogous properties to the dyeing of wool with acid dye. The rate of dyeing curves at the temperatures, 90° and 100°C., which are usual for the dyeing, are analysed by diffusion equation in the non-steady state, and nearly equal diffusion constants are obtained by applying various theoretical equations.