Abstract
In order to dye polyurethane synthetic leather with acid or substantive dyes, basic amino-groups were introduced on the polymer prepared by wet process by means of three methods; (1) graft reaction to the unsaturated groups which were preintroduced on nitrogen of the polyurethane by anionic reaction, (2) preparation of the polyurethane by using nitrogen containing chain extending reagents, and (3) radical graft reaction of nitrogen. containing monomers onto the polyurethane. The best result was obtained by the third method in which N-vinylpyrrolidone (NVP) was reacted in DMF with the polyurethane using AIBN. Since no solvent for fractionation was found, the graft percentage was not determined, but was assumed small. The grafting copolymerizations of NVP with vinyl monomers insoluble in water were also carried out to prevent the dissolution of the grafted polymer. 2-Diethylaminoethyl methacrylate (DEM) gave a good result for dyeing degree and homogeneity. Blending of the polyurethane and copolymer of NVP and DEM did not lead to homogeneous dyeing. These polymers were found to be incompatible as judged from the dynamic viscosity of the mixed polymer solution.
