Aqueous dispersions of polyurethane–polyvinyl pyridine cationomers and their application as binder in base coat for leather finishing

This article deals with synthesis of poly(urethane-co-vinylpyridine) block copolymer dispersions and their application as binder in leather finishing. Polyurethanes (PUs) with built in iniferter fragments were used to synthesize block copolymers with controlled incorporation of vinyl pyridine (VPy) units. Cationomers of the block copolymers were prepared by quaternising the polyvinyl pyridine groups and the ionomers were subsequently dispersed in water. FT-IR and FT-NMR studies were used to confirm the structure of the block copolymers. Increase in the ionic content and incorporation of vinyl pyridine groups led to an increase in thermal stability as revealed by thermogravimetric analysis. DSC results indicated that the phase separation increased when the block copolymers were converted to ionomer. Poly(urethane-co-vinylpyridine) block copolymeric dispersions were used as binder in leather finishing. The performance of the dispersions as binder was assessed by standard testing procedures and found to be comparable with commercial products with decided advantage over cost.