Synthesis of a Novel Silica Modified Environmentally Friendly Waterborne Polyurethane Matting Coating

A prepolymer of waterborne polyurethane (WPU) was synthesized from isophorone diisocyanate, hexamethylene diisocyanate trimer, polyoxypropylene glycol, polycaprolactone, dimethylol propionic acid and triethylamine. Silicon dioxide (SiO2) was modified by N-(beta-aminoethyl)-gamma-aminopropyltriethoxysilane in water, through which active amino groups were introduced on the modified SiO2 surface. Then, the water solution was directly added into the WPU prepolymer for emulsification, these active amino groups participate in isocyanate reaction and chain extension. Finally, modified SiO2 compounds were grafted into polyurethane chains, forming environmentally friendly matting material. The properties of the synthesized matting material were characterized through Fourier transform infrared spectroscopy, laser particle analysis, scanning electron microscopy, volatile organic compound content test, solid content test, viscosity measurement, stability test, specular gloss, wet-dry rubbing fastness, etc. The glossy behavior, mechanical property and stability of the matt WPU material exhibited remarkable performances and showed good commercial potential.