No abstract

Aqueous solubilities have been determined at 25° and 80°c. for a range of purified disperse dyes. The solubilising effect of a number of dispersing agents has been examined. It is shown that aqueouS solubility has some bearing on the rate of dyeing of disperse dyes and largely governs their levelling power. Addition of a dispersing agent to an acetate rayon dyebath reduces the percentage exhaustion to an extent which is proportional to the degree of solubilisation.

Linear isotherms have been obtained on viscose rayon, in the range 20-90"C, with benzidine, 0-and o-Tolidine has much higher affinity for cellulose than Non-m-tolidine, and derivatives of arninoazobenzene. the non-coplanar m-tolidine. ionic dyes do not appear t o forni aygregat,rs in aqueous solution.Heats of dyeing were found to be comtant, between 40 and 80°C.

The partition of disperse dyes between water and cellulose acetate has been studied by means of desorption experiments, and the results have been used to calculate values for affinity, heat of dyeing, and entropy change. Aqueous solubilities have been determined at different temperatures in order to obtain heats of aqueous solution, and values for fibre saturation and heat of solution in the fibre have been calculated.

The behaviour on unmodified polypropylene fibre and film of two commercial disperse dyes and Dimethyl Yellow has been examined. The results indicate that disperse dyes capable of dyeing polypropylene fibre have high diffusion coefficients and low saturation values. Linear adsorption isotherms were obtained with Dimethyl Yellow. The behaviour of polypropylene fibre towards disperse dyes in general is discussed.