Anchor coating of a water-soluble salt of a copolymer of an acrylate and an acrylic ester

Claim 1

IN A PROCESS FOR IMPROVING THE PROPERTIES OF REGENERATED CELLULOSE FILM WHEREIN THE REGENERATED CELLULOSE FILM IS CAST, PURIFIED, SOFTENED, DRIED AND COATED WITH A COALESCIBLE FILM-FORMING MATERIAL FROM AN AQUEOUS DISPERSION OF SAID MATERIAL AND THE COATING IS THEN SMOOTHED AND DRIED, THE IMPROVEMENT WHICH COMPRISES APPLYING TO SAID FILM AFTER PURIFICATION BUT PRIOR TO THE FIRST DRYING STEP AN AQUEOUS SOLUTION CONTAINING A WATER-SOLUBLE SALT OF A POLYMER OBTAINED FROM 20 TO 30 PERCENT BY WEIGHT OF AT LEAST ONE DIALKYLAMINOETHYL ACRYLATE HAVING THE FORMULA H2C=C(-R1)-COO-CH2-CH2-N(-R2)2 AND 70 TO 80 PERCENT BY WEIGHT OF AT LEAST ONE ACRYLIC ESTER HAVING THE FORMULA H2C=C(-R1)-COO-R3 WHEREIN R1 IS SELECTED FROM THE GROUP CONSISTING OF HYDROGEN AND METHYL, R2 IS AN ALKYL GROUP OF 1-6 CARBONS ATOMS, R3 IS SELECTED FROM THE GROUP CONSISTING OF METHYL, PINACOLYL, TERTIARY BUTYL AND NEOPENTYL, SAID POLYMER HAVING AN INHERENT VISCOSITY OF 0.1-1.0, SAID SALT BEING FORMED WITH A FATTY ACID HAVING UP TO SIX CARBON ATOMS; REMOVING EXCESS SOLUTION; AND, THEREAFTER, HEATING SAID FILM UNDER CONTROLLED CONDITIONS OF TEMPERATURE AND TIME TO DRY THE FILM AND INSOLUBILIZE THE POLYMER; AND THEN APPLYING TO SAID FILM A COALESCIBLE FILMFORMING MATERIAL FROM AN AQUEOUS DISPERSION THEREOF.