Resin-impregnated leather board

Claim 1

IN A METHOD OF MAKING LEATHER BOARD BY THE STEPS OF PREPARING AN AQUEOUS SUSPENSION OF FIBROUS SHEET-FORMING MATERIAL INCLUDING A MAJOR PROPORTION OF LEATHER FIBERS, IMPREGNATING THE FIBROUS MATERIAL WITH A WATER-INSOLUBLE HYDROPHOBIC ORGANIC IMPREGNATING AGENT AND FORMING THE IMPREGNATED FIBROUS MATERIAL INTO A FELTED PRODUCT, THE IMPROVEMENT WHICH CONSISTS IN FIRST ADDING TO THE AQUEOUS FIBER SUSPENSION 1-15% OF MELAMINE RESIN, BASED ON THE DRY WEIGHT OF SAID FIBROUS MATERIAL, IN THE FORM OF A COLLOIDAL SOLUTION OF CATIONIC HYDROPHILIC MELAMINE -FORMALDEHYDE RESIN, THEN AGING THE SUSPENSION FOR AT LEAST 30 MINUTES, THEN ADDING AN AQUEOUS DISPERSION OF THE WATER-INSOLUBLE HYDROPHOBIC ORGANIC IMPREGNATING AGENT IN DEFLOCCULATED CONDITION AND FLOCCULATING THE IMPREGNATING AGENT IN THE PRESENCE OF THE SUSPENDED FIBERS BY THE ACTION OF THE CATIONIC MELAMINE RESIN, AND THEREBY DEPOSITING THE IMPREGNATING AGENT UNIFORMLY ON THE FIBERS ALONG WITH MELAMINE-FORMALDEHYDE RESIN.