Phosphate conversion coating accelerators
AssigneeGerhard Collardin GmbH
InventorsHeinz Portz, Othmar V. Ettingshausen
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Abstract
Phosphate conversion coating accelerators consisting essentially of amidosulfonic acid, N-substitution products and salts thereof, sulfonamides, 1,2,3-oxathiazin-4(3H)-one salts or 6-alkyl derivatives thereof, and ortho-aniline sulfonic acid or its derivatives aklyl-substituted on the ring and salts thereof, and mixtures of the foregoing, and a process for their use.
Claims36
A phosphating composition for zinc-, iron-, or zinc-iron-phosphate conversion coatings, excluding nitrite as an accelerator, and containing an accelerator which is one of the following compounds, its alkali metal salt or ammonium salt, or any mixture thereof:
- ##STR5## wherein:
- R.sup.1 is
- (i) a C.sub.1-4 linear or branched alkyl radical,
- (ii) a C.sub.5-6 saturated carbocyclic or heterocyclic radical, or
- (iii) an aryl or aralkyl radical having at least 6 members;
- and
- R.sup.2 is
- (i) hydroxy,
- (ii) --O.sup.- M.sup.+ in which N.sup.+ is an alkali metal or an ammonium ion, of
- (iii) an aromatic ring having at least 6 members, optionally substituted by a hydroxy, amino, (C.sub.1-3 alkyl)--CO--NH or (carboxy C.sub.1-3 alkyl)--CO--NH radical;
- ##STR6## wherein, R.sup.3 is
- (i) hydrogen,
- (ii) hydroxy, or
- (iii) anamino radical;
- ##STR7## wherein:
- R.sup.4 is
- (i) hydrogen, or
- (ii) a C.sub.1-4 linear or branched alkyl radical and
- M.sup.+ is an alkali metal or an ammonium ion.
In a process for the accelerated and layer-refining application of phosphate coatings to metal surfaces using phosphating solutions based on zinc phosphate and/or iron phosphate and/or zinc-iron phosphate as the principal layer-forming component, in admixture with an accelerator, excluding nitrite the improvement comprising using as the accelerator a composition consisting essentially of one of the following compounds, its alkali metal salt or ammonium salt, or any mixture thereof:
- ##STR8## wherein:
- R.sup.1 is,
- (i) a C.sub.1-4 linear or branched alkyl radical,
- (ii) a C.sub.5-6 saturated carbocyclic or heterocyclic radical, or
- (iii) an aryl or aralkyl radical having at least 6 members;
- and
- R.sup.2 is
- (i) hydroxy,
- (ii) --O.sup.- M.sup.+ in which M.sup.+ is an alkali metal or an ammonium ion, or
- (iii) an aromatic ring having at least 6 members, optionally substituted by a hydroxy, amino, (C.sub.1-3 alkyl)--CO--NH or (carboxy C.sub.1-3 alkyl)--CO--NH radical;
- ##STR9## wherein:
- R.sup.3 is
- (i) hydrogen,
- (ii) hydroxy, or
- (iii) an amino radical;
- ##STR10## wherein:
- R.sup.4 is
- (i) hydrogen, or
- (ii) a C.sub.1-4 linear or branched alkyl radical, and
- M.sup.+ is an alkali metal or an ammonium ion.
Dependencies are inferred from the claim text.