Method of producing an organic, corrosion-resistant surface coating

A method of producing an organic, corrosion-resistant surface coating on a corrodible metal surface comprising:

• treating a corrodible metal surface with a composition comprising
• a) an organic film-forming binder;
• and
• b) a corrosion-inhibiting amount of a water-insoluble salt of
• i) a ketoacid having the formula (I):
• ##STR16## wherein a is 1, 2, 3, 4 or 5;
• the R substituents are the same or different and each is hydrogen;
• halogen;
• nitro;
• cyano;
• CF.sub.3 ;
• C.sub.1 -C.sub.15 alkyl;
• C.sub.5 -C.sub.12 cycloalkyl;
• C.sub.2 -C.sub.15 alkenyl;
• C.sub.1 -C.sub.12 halogenoalkyl;
• C.sub.1 -C.sub.12 alkoxy;
• C.sub.1 -C.sub.12 thioalkyl;
• C.sub.6 -C.sub.12 aryl;
• C.sub.6 -C.sub.10 aryloxy;
• C.sub.7 -C.sub.12 aralkyl;
• --CO.sub.2 R.sub.1 in which R.sub.1 is a) hydrogen, b) C.sub.1 -C.sub.20 alkyl or said alkyl interrupted by one or more O-, N- or S-atoms, c) C.sub.7 -C.sub.12 aralkyl or d) C.sub.6 -C.sub.12 aryl or said aryl substituted with one or more carboxy groups;
• --COR.sub.1 in which R.sub.1 has its previous significance;
• NR.sub.2 R.sub.3 in which R.sub.2 and R.sub.3 are the same or different and each is hydrogen or C.sub.1 -C.sub.24 alkyl or said alkyl interrupted by one or more O, S or NH moieties;
• or when a is 2, 3, 4 or 5, two adjacent groups R may be the atoms required to form a fused benzene or cyclohexyl ring;
• and n is an integer from 1 to 10;
• and
• ii) an amine of formula II:
• ##STR17## wherein X, Y and Z are the same or different, and are hydrogen;
• C.sub.8 -C.sub.24 alkyl or said alkyl interrupted by one or more O-atoms;
• phenyl;
• C.sub.7 -C.sub.9 phenylalkyl;
• C.sub.7 -C.sub.9 alkylphenyl;
• or two of X, Y and Z together with the N-atom to which they are attached form a 5-, 6- or 7-membered heterocyclic residue, or said residue containing a further oxygen, nitrogen or sulphur atom or said residue substituted by one or more C.sub.1 -C.sub.4 alkyl, amino, hydroxy, carboxy or C.sub.1 -C.sub.4 carboxy alkyl groups, and the other of X, Y and Z is hydrogen;
• provided that X, Y and Z are not simultaneously hydrogen;
• then dry or curing the coating composition to produce a dried or cured surface coating on the metal surface.