BLENDS OF GLYOXALATED POLYACRYLAMIDES AND PAPER STRENGTHENING AGENTS

摘要

Compositions comprising a blend of two or more paper strengthening agents have improved stability compared with previously known paper strengthening agents. One component is a polymeric paper strengthening agent, preferably a wet strengthening agent. The other component is a stabilized glyoxalated polyacrylamide prepared by (1) reacting a first portion of glyoxal with a polyacrylamide having pendant amide groups to form a first reaction mixture comprising glyoxalated polyacry-lamide; (2) adding an acid to the first reaction mixture to form a second reaction mixture having a reduced pH and comprising the glyoxalated polyacrylamide; and (3) adding a second portion of glyoxal to the second reaction mixture to form the stabilized gly-oxalated polyacrylamide. If desired, an aldehyde scavenger can be included in one or more of step (1), step (2), step (3), or the sta-bilized glyoxalated polyacrylamide. Such compositions can be used to enhance the strength of paper, particularly the wet strength of paper.