Abstract
The effect of tannic acid on the paint adhesion of zinc was investigated, since our previous investigations showed that the adhesion was improved by a treatment with an aqueous solution of tannic acid. The structure of the film formed on zinc in the tannic treatment was determined with IR, ESCA, and UV. Experimental data suggested that the film was composed of zinc carboxylate and that OH groups of tannic acid were strongly attached to zinc surface by hydrogen bonding between zinc surface and OH groups. Therefore, it is concluded that adhesion of paint on zinc depends on the effect of the functional group contained in the tannic acid film lying between zinc substrate and a paint film.
