Metal coating with hexavalent chromium compound

Claim 1

A PROCESS FOR REDUCING CORROSION AND IMPROVING PAINT ADHESION OF METALS, SAID PROCESS BEING CHARACTERIZED BY THE APPLICATION TO THE METAL''S SURFACE OF AN AQUEOUS DISPERSION OF A NON-WAXY HYDROPHOBIC RESIN, A HEXAVALENT CHROMIUM COMPOUND OF THE CLASS CONSISTING OF CHROMIC ACID AND WATER-SOLUBLE DICHROMATES OF METALS HAVING A VALENCE HIGHER THAN 1, SAID DISPERSION ALSO CONTAINING A WATER-SOLUBLE REDUCING AGENT FOR THE CHROMIUM IN THE CHROMIUM COMPOUND, THE REDUCING AGENT BEING COMPATIBLE WITH THE DISPERSION FOR AT LEAST ONE HOUR AT 80* F, AND THE WEIGHT RATIO OF RESIN TO THE CHROMIC ACID EQUIVALENT OF THE CHROMIUM COMPOUND RANGING FROM ABOUT 1:5 TO 5:1 AND THEN DRYING THE APPLIED AQUEOUD DISPERSION ON THE SURFACE OF THE METAL AT A TEMPERATURE OF AT LEAST 212* F, TO CAUSE THE REDUCING AGENT TO REDUCE THE CHROMIUM IN THE CHROMIUM COMPOUND TO TRIVALENT CONDITION, AND THE APPLIED DISPERSION TO BE CONVERTED TO AN ADHERENT FILM WWEIGHING AT LEAST 40 MILLIGRAMS PER FOOT, THE PROPORTION OF REDUCING AGENT SUCH THAT FORM ABOUT 40 TO 95% OF THE CHROMIUM IS REDUCED DURING SAID DRYING.