Crosslinked vinyl alcohol/vinylamine copolymers for dry end paper addition.

摘要

The mfr. of paper having improved strength properties comprises adding to the paper stock 0.1-8 wt.% of a PVA/vinylamine copolymer contg. 0.5-25 mole% vinylamine units and also a crosslinking agent capable of crosslinking the copolymer to the dry end of the papermaking process. The crosslinking agent comprises glyoxal, glutaraldehyde, phenol-formaldehyde resins, urea-formaldehyde, melamine-formaldehyde, epoxy resins, maleic anhydride copolymers, diisocyanate and/or dicarboxylic acids. The PVA/vinylamine copolymer is produced by the hydrolysis of the corresp. PVAc/N-vinylamide copolymer; and contains 2-12 mole% vinylamine units.