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.