Wet strength paper containing linear polyamide resin

Claim 1

PROCESS OF MAKING PAPER OF IMPROVED WET AND DRY STRENGTH WHICH COMPRISING FORMING A DILUTE AQUEOUS SLURRY OF CELLULOSE PAPERMAKING FIBERS, ADDING THERETO A SMALL BIT EFFECTIVE AMOUNT AS STRENGTHENING AGENT OF A WATERSOLUBLE CATIONIC THERMOSETTING METHYLENEBISACRYLAMIDEALKYLENEPOLUAMINE-CYANATE-FORMALDEHYDE RESIN, SAID RESIN BEING PREPARED BY REACTING A WATER-SOLUBLE METHYLENEBISACRYLAMIDE-ALKYLENEPOLYAMINE CONDENSATION PRODUCT HAVING A GARDENER-HOLDT VISCOSITY OF AT LEAST B AS A 33% BY WEIGHT AQUEOUS SOLUTION AT 25*C. FIRST WITH SUFFICIENT OF A WATER-SOLUBLE METAL CYANATE TO CARBAMYLATE AT LEAST 80% OF ALL PRIMARY AND SECONDARY NITROGEN ATOMS THEREIN AND THEN WITH SUFFICIENT FORMALDEHYDE TO CONVERT SAID CARBAMYLATED CONDENSATION PRODUCT TO THERMOSETTING FORM, SHEETING SAID FIBERS TO FORM A WEB, AND HEATING SAID WEB AT 190*-250*F. TO DRY THE SAME AND DEVELOP THE STRENGTHENING PROPERTIES OF THE RESIN THEREON.