Novel heat-resistance UV curable waterborne polyurethane coatings modified by melamine

Novel UV curable waterborne polyurethane coatings (UVWPU) modified by melamine was prepared using isophorone diisocyanate (IPDI), polyethylene glycol (PEG), alpha,alpha-dimethylol propionic acid (DMPA), hydroxyethyl acrylate (HEA) as main materials. Copolymer structure was verified using Fourier transform infrared spectroscopy (FT-IR). Performance of the coatings was evaluated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), and mechanical tests such as pencil hardness and resistance to water. The results showed that the modified UVWPU film had the good thermal resistance, water resistance and mechanical properties. The optimum melamine dosage was 4.70 wt.%, the glass transition temperature (T-g) of the modified film increased by 20.4 degrees C and 5% weight-loss temperature (253 degrees C) increased by 105 degrees C. No change color, crinkle, desquamate, dehisce and frothy were found after the modified film dried at 130 degrees C for 2 h. (c) 2011 Published by Elsevier B.V.