Water-resistant alkaline corrugating adhesive composition

摘要

A crosslinking additive for imparting water resistance to starch-based corrugating adhesive compositions is prepared by reacting acetone and formaldehyde under aqueous alkaline conditions at 20 DEG -80 DEG C. in a molar ratio of 1 mole acetone to about 2 to 5.5 moles formaldehyde, adding to the reaction mixture at least an effective amount of dihydroxyethylene urea to scavenge the free formaldehyde in the mixture, and reacting until the amount of unreacted formaldehyde remaining is reduced to about 0.1-2%. The crosslinking additive thus obtained, which is low in free formaldehyde, may be added directly to a starch-based corrugating adhesive or may be first mixed with dimethylol dihydroxyethylene urea.