EFFECTS OF THIXOTROPIC AGENTS ON THE VISC OELASTIC PROPERTIES OF PAINTS FOR AUTOMOBILES

The effect of thixotropic agents in paints was studied using a rheomet er which makes possible instant changes of the shear rate from a high value to a low value. The viscoelastic properties of two kinds of pain ts, containing different kinds of thixotropic agents, were studied in comparison with the properties of a paint which does not contain any t hixotropic agent. From shear rate dependences of steady shear viscosit y and apparent steady-state compliance, it was confirmed that a struct ure is formed in the paints at low shear rates, but destroyed at high shear rates. The structure once destroyed requires several minutes for recovery. The effect of thixotropic agents in paints should be carefu lly reconsidered.