Method for tanning leather with aminoplasts and compositions therefor

Claim 1

A COMPLETELY WATER-SOLUBLE AND INDEFINITELY STABLE ANIOMIC AMINOPLAST RESIN PRODUCED BY MIXING (A) MELAMINE,(B) DICYANDIAMIDE, (C) FORMALDEHYDE AND (D) AN INORGANIC ALKALI BISULFITE, HEATING SAID MIXTURE TO, AND MAINTAINING IT AT, ITS REFLUX TEMPERATURE FOR A PERIOD OF ABOUT TWO HOURS, SUBSEQUENTLY ADDING (E) UREA THERETO AND HEATING THE MIXTURE THUS OBTAINED TO ITS REFLUX TEMPERATURE AND MAINTAINING SAID MIXTURE AT ABOUT REFLUX TEMPERATURE FOR A PERIOD OF ABOUT THIRTY MINUTES, THERE BEING PRESENT IN THE REACTION MIXTURE A RATIO OF FROM ABOUT 1.3 MOLS TO 1.7 MOLS OF (B), FROM ABOUT 8.0 MOLS TO ABOUT 12.0 MOLS OF (C), FROM ABOUT 1.3 MOLS TO ABOUT 1.7 MOLS OF (D), AND FROM ABOUT 1.5MOLS TO ANOUT 2.0 MOLS OF (E), FOR EACH MOL OF (A) EMPLOYED.