Multistage addition of retention system to an aqueous papermaking suspension using biguanidine condensate, epichlorohydrin/dimethylamine condensate and polyacrylamide

摘要

Multistage addition of retention system to an aqueous papermaking suspension using biguanidine condensate, epichlorohydrin/dimethylamine condensate and polyacrylamide. Production from a fiber/filler mixture of an aqueous suspension giving well-formed paper with high retention and low porosity is by addition of a retention system by: (i) adding a biguanidine condensate before the heating disperser or at the dry broke pulper; (ii) adding a medium mol. wt., highly cationic, branched epichlorohydrin/dimethylamine condensate in the low viscosity region; and (iii) adding an anionic polyacrylamide before or in the vertical sieve.