Core/shell acrylic microgels were synthesized by emulsion polymerization. The core is slightly crosslinked by a difunctional monomer and the shell contains a sufficient amount of carboxyl groups which are partially or fully neutralized by amines. After neutralization, sufficient pseudoplastic flow behavior due to the mutual interaction of the polymer particles at low solid contents below 20w.t.% in the final metallic basecoat paint can be achieved. As a results, the orientation of aluminium flakes with the extreme shrinkage of low solids metallic basecoat during flash-off time is parallel to the surface of substrate(flop effect). Dynamic rheological property was also found to influence the flop effect of metallic basecoats.