Process of making a battery separator

Claim 1

THE PROCESS OF MAKING A LIQUID PERMEABLE BATTERY SEPARATOR WHICH COMPRISES IMPREGNATING A BIBULOUS CELLULOSIC FIBROUS SHEET HAVING AN ALPHA CELLULOSE CONTENT OF AT LEAST 90 PERCENT AND HAVING AN AIR PERMEABILITY (GURLEY) OF FROM 1 TO 10 SECONDS WITH AN AQUEOUS SOLUTION OF AN ASTAGE PHENOL-FORMALDEHYDE RESIN AND A WETTING AGENT, IN SUCH MANNER THAT SAID SHEET PICKS UP FROM 25 TO 50 PERCENT BY WEIGHT OF SAID RESIN BASED ON FIBER PLUS RESIN, DRYING SAID SHEET AND THEREBY DEPOSITING SAID RESIN AND WETTING AGENT IN AND AROUND THE FIBERS OF THE SHEET AND THERETHAT UPON ADVANCING SAID RESIN TO THE C-STAGE SAID FIBERS WILL BE PROTECTED AGAINST BATTERY ACID BUT THE AIR PERMEABILITY OF THE SHEET WILL NOT BE MATERIALLY LOWERED, HEATING THE DRIED SHEET TO A TEMPERATURE OF FROM 300* TO 550* F. TO ADVANCE SAID RESIN TO THE C-STAGE, APPLYING AN AQUEOUS SOLUTION OF THE SAME WETTING AGENT TO THE CURED SHEET, AND CUTTING THE RESULTING SHEET INTO BATTERY SEPARATORS, THE WETTING AGENT APPLIED FROM THE AQUEOUS SOLUTION OF THE RESIN GREATLY FACILITATING DISTRIBUTION OF THE AQUEOUS SOLUTION OF THE WETTING AGENT SUBSEQUENTLY APPLIED TO THE CURED SHEET, THE TOTAL AMOUNT OF SAID WETTING AGENT INTRODUCED INTO THE SEPARATOR BEING EQUAL TO FROM 1 TO 10 PERCENT BY WEIGHT BASED ON THE CURED RESIN CONTENT OF THE SEPARATOR, FROM ONE-THIRD TO ONEHALF OF SAID WETTING AGENT BEING APPLIED FROM