Manufacture of leather sheets containing normally tacky impregnating agents

Claim 1

IN A METHOD FOR MAKING AN IMPREGNATED LEATHER SHEET BY THE STEPS OF PREPARING AN AQUEOUS STOCK OF LEATHER FIBERS, ADDING AN AQUEOUS COLLOIDAL DISPERSION OF A NORMALLY TACKY, WATER-INSOLUBLE HYDROPHOBIC ORGANIC IMPREGNATING AGENT CONTAINING A SOAP AS PRINCIPAL DISPERSING AGENT THEREFOR, DEPOSITING SAID IMPREGNATING AGENT ON THE FIBERS WHILE IN AQUEOUS SUSPENSION, AND FORMING THE FIBERS INTO A SHEET, THE STEPS OF FIRST ADDING TO THE FIBER SUSPENSION AT PH BETWEEN ABOUT 3 AND 7 A COLLOIDAL CATIONIC DIMETHYLOLUREA WATER-SOLUBLE POLYFUNCTIONAL NITROGEN BASE RESIN, THEN ADDING SAID AQUEOUS DISPERSION OF TACKY IMPREGNATING AGENT CONTAINING, IN ADDITION, A NON-IONIC SURFACE-ACTIVE AGENT AND AN ANIONIC SURFACE-ACTIVE AGENT SELECTED FROM THE GROUP CONSISTING OF THE ALUM-STABLE SULFONATE AND THE ALUM-STABLE SULFATE DISPERSING AGENTS, AND SHEETING AND DRYING THE FIBERS; THE WEIGHT OF SAID IMPREGNANT BEING BETWEEN ABOUT 15% AND 100% OF THE WEIGHT OF THE FIBERS; THE WEIGHT OF SAID CATIONIC RESIN BEING ABOUT 5% AND 15% OF THE WEIGHT OF SAID IMPREGNANT, THE WEIGHT OF NON-IONIC AGENT BEING BETWEEN 1% AND 10% OF THE WEIGHT OF THE FIBERS, AND THE WEIGHT OF ANIONIC SURFACE-ACTIVE AGENT BEING BETWEEN 25% AND 100% OF THE WEIGHT OF NON-IONIC SURFACEACTIVE AGENT.