Leather finishing : Preparation and application of cationic organosilicone/polyurethane micro-emulsion

Using a catalyst and cosolvent, hydroxyl-terminated polydimethylsiloxane (HPMS) based polyurethane (PU) micro-emulsion (WPU/HPMS) derived from isophorone isocyanate (IPDI) and poly- tetramethylene glycol (PTMG) was synthesised by self-emulsifying copolymerization. The polymer was then used in leather finishing. The structure, rheological behavior, morphology and heat performance were characterized by Fourier transform infared spectroscopy (FT-IR), 'H nuclear magnetic resonance ('H NMR), gel permeationchromatography (GPC), light scattering (LS), transmission electron microscopy (TEM), interfacial tension (IT), wide-angle X-ray diffraction (WAXD), differential scanning calorimeter (DSC) and thermogravimetry (TG). The results reveal that WPU/HPMS micro-emulsion is endowed with low surface tension, pseudoplasticity and thixotropy, which are beneficial to the properties of coating. DSC and TG diagrams also reveal that the application range of product was enlarged. Furthermore, the WPU/HPMS micro-emulsion was found to be a good finishing agent, endowing leather with a brightness, softness, plump/full and smooth surface, and thus improving the quality of leather.