Composition and process for treating tinplate
AssigneeHenkel Corporation
InventorsTomoyuki Aoki, Masayuki Yoshida
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Abstract
To impart an excellent corrosion resistance and adherence to the surface of tinplate while avoiding the production of sludge in the treatment bath during continuous treatment, a bath is used that contains phosphate ions, from 0.1 to 5.0 g/L of chelating agent, and tin ions; has a pH from 2.0 to 4.5; is essentially free of oxidizing agent and ferric ion; and has an oxidation-reduction potential of .ltoreq.450 mV more oxidizing than a silver-saturated silver chloride reference electrode.
Claims20
An aqueous liquid composition suitable for treating tinplate surfaces, said composition having a pH in the range from 2.0 to 4.5 and an oxidation- reduction potential not greater than 450 mV more oxidizing than a silver-saturated silver chloride reference electrode, and consisting essentially of water and:
- (A) from 1 to 30 g/L of phosphate ions,
- (B) from 0.1 to 5.0 g/L of chelating agent, and
- (C) from 0.01 to 2.0 g/L of tin ions.
Dependencies are inferred from the claim text.