Study of film properties of some urethane oils

In this study, sunflower oil-based urethane oils were obtained from three kinds of isocyanate components: toluene diisocyanate (TDI), hexamethylene diisocyanate (HMDI) and poly(1,4-butandiol) toluene 2,4-diisocyanate (PBTDI) terminated prepolymer. The polymers were prepared at four different ratios of isocyanate component/oil. Sunflower and linseed oil alkyd resin samples were also prepared as the comparative samples. The results suggest that the viscosity and the film properties of urethane oils depend on the amount and type of isocyanate component. The increase in isocyanate content of the urethane oils caused high viscosity. In comparison with the samples having the same oil content, PBTDI-based samples showed the highest viscosity. Viscosity of the polymers can dramatically affect some film properties. For example, high polymer viscosity caused short drying time. In comparison of alkali and water resistances of urethane oils with those of alkyd resins, better results were obtained depending on the structure of the urethane oils. On the other hand, alkyd resins and TDI-based polymers exhibited the best hardness properties.