Physical Properties of Thermosetting Amino-Alkyd Resin Coatings

Abstract

Shrink properties and modulus of elasticity of thermosetting amino-alkyd resin coating were studied.
In the urea-melamine resin mixture system, shrinkage stress and shrinkage strain showed a maxium at 80% urea content and decreased with increase of the melamine resin content. This trend seems a synergistic effect of functional group in the melamine resin with acid catalyst in the urea resin. The modulus of elasticity showed a maximum at 100% urea resin content and decresaed curvilinearly with increase of the melamine resin content. This was caused by the effect of acid catalyst in the urea resin.
In the urea-soya bean fatty acid modified alkyd resin system, the modulus of elasticity increased with increase of the urea resin content. In the melamine-soya bean fatty acid modified alkyd resin system, it showed a maximum value in the vicinity of melamine : alkyd=50 : 50. In the melamine-castor oil modified alkyd resin system, it increased up to 30% alkyd resin content, but showed a saturated line by increasing beyond it.
In the urea-alkyd resin system, shrinkage stress showed a maximum at 80% urea resin content, but in the melamine-alkyd resin system, it showed a maximum in the vicinity of 60-70% urea con-tent. It was also shown that the shrinkage stress decreased in order of urea-soya bean fatty acid modified alkyd (hereafter referred as soya bean alkyd) >melamine-soya bean alkyd >melamine-castor oil modified alkyd (hereafter referred as castor oil alkyd).
Shrinkage strain of soya bean oil alkyd was almost the same as urea and melamine resins, but that of melamine-castor oilalkyd was slightly larger than that.
Further, the modulus of elasticity, shrinkage stress and shrinkage strain were also related with acid value.