THE EFFECTS OF RHEOLOGY VARIATION ON REACTIVE DYE PRINT PARAMETERS

Series of print pastes based on alginate and synthetic thickeners were prepared. Dye and dye concentration together with thickener concentra tion were varied. The rheology of each paste was measured using a rang e of shear rates. The pastes were printed on a rayon fabric using a la boratory rotary screen printing machine, and the prints were analyzed for the following parameters-mass of paste transferred, % fixation, K/ S (color value), penetration, spread. The relationship between these v arious parameters and the measured rheologies was examined. It was fou nd that no single viscosity measurement accurately predicted all of th e parameters for both thickener types. However, a number of close rela tionships were found, and the value of the traditional viscosity measu rement in the printing industry was established. The reasons for the c ontinuing preeminence of natural alginate pastes for the printing of r eactive dyes over newer synthetic materials is discussed.