Process for making cellulose fibrous sheet

Claim 1

A PROCESS FOR MAKING FIBROUS SHEETS WHICH COMPRISES TREATING CELLULOSE FIBERS IN AN AQUEOUS SOLUTION CONTAINING AN ALUMINUM SALT DISSOLVED THEREIN, THE RESULTANT MIXTURE OF FIBERS AND SALT SOLUTION CONTAINING AT LEAST 10% BY WEIGHT OF THE ALUMINUM SALT, REMOVING EXCESS SOLUTION FROM THE FIBERS, RAPIDLY RINSING THE FIBERS WITH WATER RAPIDLY REDISPERSING THE RINSED FIBERS IN WATER TO FORM A SUSPENSION THEREOF HAVING A CONSISTENCY OF 0.1 TO 6% BY WEIGHT OF FIBERS ON THE WEIGHT OF WATER, AND THEN, PROMPTLY AFTER REDISPERSING THE FIBERS, MIXING INTO THE FIBER SUSPENSION AN AQUEOUS DISPERSION OF A WATER-INSOLUBLE ADDITION POLYMER, IN AN AMOUNT FROM 1 TO 150% BY WEIGHT OF THE POLYMER BASED ON THE WEIGHT OF THE FIBERS, TO THEREBY DEPOSIT THE POLYMER ON THE FIBERS, AND THEN FORMING A SHEET FROM THE RESULTING FIBER SUSPENSION, THE STEPS OF THE PROCESS PRIOR TO THE AFORESAID MIXING STEP SERVING TO PROVIDE ALUMINUM IONS AND ANIONS OF SAID SALT ON THE FIBERS WHEN THE POLYMER IS MIXED INTO THE FIBER SUSPENSION.