The Release of Disperse Dyes from Thickener Films During Thermal Processes

The dye release properties of hydrophilic polymer layers containing disperse dye particles have been studied. Polymers which form homogeneous films, such as sodium alginate, act as barriers to the passage of dye vapour, unless the weight of the dye particles initially present in the layer exceeds the weight of the polymer. Sodium carboxymethyl starch does not behave in this way, as the polymer film is heterogeneous. Evidence is presented for much improved dye release from coatings containing homogeneous film-forming polymers by the emulsification of hydrocarbons into printpastes. The dye coatings take on a cellular structure which allows disperse dye vapour to be readily released