METHOD FOR APPLYING A COATING TO AN IRON SURFACE, PROCESS FOR PREPARING AN AQUEOUS COATING MIXTURE SUITABLE FOR USE IN THIS PROCESS, AND IRON ARTICLES COATED IN ACCORDANCE WITH THE ABOVE

摘要

The compsn. comprises a dispersion of 5-550 g/l resin, pref. latex, in an aqs. acids phase, pref. HF. of pH 1.6-5.0 and contains is not 0.025 (0.025-20) g/l Gp VI A to IV B metal as free ions or F-contlexed ions. For heavy coatings the compsn. may contain an oxidising agent, e.g. in amt. giving 0.01-0.2 oxidation equivs. per l. other additives include 5-30 g/l coalescing agent (e.g. ethylene glycol monobutyl ether), pigments and non-ion ic or anionic wetting agents. Substrates are contacted 15 sec. to 10 mins (0.5-5 mins) at 4-49(18-35) degrees C, opt. placed in oxidising atmos. for 15 sec. to 10 mins. rinsed, then dried or fired. Metals with ionization tendency between that of Al and Cu can be coated, compared with only ferrous substrates using the process of the parent patent in which Fe (III) ions were added.