Microemulsion Copolymerization of Methyl Methacylate and 2-Ethyl Hexylacrylate as a Binder in Leather Finishing

    IN ORDER to minimize the environmental impact in leather ....industry, water-based recipes are proposed in leather finishing. The application of an acrylic emulsion as a top coat system provides an excellent balance of safety, performance and commerciality in comparison with other coats. An acrylic resin nano-size latex whose colloidal particle size is about 23 nm with solids content of about 25% is prepared by copolymerization of methyl methacrylate and 2-ethyl hexylacrylate at different monomer ratios via microemulsion polymerization technique using K₂S₂O₈ as an initiator, NaHCO₃ as a buffer and sodium dodecyl sulfate as an emulsifier, performed at 70°C for 4hr. The influences of the prepared conditions on the kinetics of emulsion polymerization are studied. The produced copolymers are applied onto leather surfaces of about 90 mm thick as measured by Elcometer thickness gau ge. The particle size of the latex is tested using dynamic light scattering (DLS), and the composition of the copolymer is analyzed by nuclear magnetic resonance (¹HNMR) and Fourier transform infrared spectroscopy (FTIR). The thermal stability and grain surface fibers texture are examined by thermal gravimetric analysis (TGA) and scanning electron microscope (SEM). Finally, the physical and mechanical properties of uncoated- and copolymer-coated leather are studied in details.