The application of chitosan in pigment printing

The use of chitosan as a combined thickener and binder in pigment printing has been examined in comparison with a commercial printing system (Alcoprint). Printing pastes made up from mixtures of chitosan, pigment and acetic acid at the appropriate viscosity gave satisfactory prints on polyester and 67:33 polyester/cotton woven fabrics. Rheological data showed the chitosan pigment paste had a much lower yield point than commercial printing paste though no difficulties were found in its use. Curing of the chitosan print at 150°C for 6 min gave samples of comparable colour fastness to the commercial printed samples when subjected to the rubbing and washing tests. The only drawbacks noted in using chitosan in this way were a reduced colour yield and a much higher fabric stiffness.