CHITOSAN IN LEATHER PRODUCTION .4. THE ENHANCEMENT OF UPTAKE OF ANIONIC DYES ON HEAVILY RETANNED LEATHER

The extent of uptake of four non-metallised acid dyes onto heavily retanned chrome grain leather was enhanced by means of pretreatment with chitosan formate; pretreatment also enhanced the fullness and handle of the dyed substrates. Optical microscopic evidence suggests that the polyaminosaccharide may be deposited mainly at the surface of the substrate and that enhanced dye uptake occurs predominantly onto this surface layer of chitosan. The extent of intensification of shade of C.I. Acid Brown 75 obtained by pretreatment with the polymer was similar to that secured using three typical, commercial cationic agents.