Formulation and testing of a waterborne primer containing chestnut tannin

The development of a water-based pretreatment system containing chestnut ta nnin and phosphoric acid and the assessment of its anticorrosive properties through different conventional tests are discussed in this work. Treated s teel panels coated with different paint systems were subjected to standardi zed (salt spray, humidity chamber, adhesion, and flexibility) and electroch emical (corrosion potential, EIS) tests. electrochemical tests were perform ed by employing only panels coated with the wash primer to determine its pr otective effect. The binder employed in this research was prepared in the l aboratory by emulsion polymerization of acrylic monomers. It was found that the tested formulation protected steel against corrosion by forming ferric tannate, which prevented oxide formation. After performin g the salt spray tests, it was observed that no oxide spots developed on th e scratch mark, although some blisters were detected. The good stability of the binder in low pH media (pH: 2.0-2.5) and the binder/substrate interact ion are decisive factors in the performance of this aqueous pretreatment sy stem.