The Effect of Chemical Cross-Linking Agents on Starch and Starch-Latex Adhesive Mixtures in Coating Color Formulations

Various representative coatings were prepared, run, and resulting papers evaluated with great emphasis placed on keeping conditions constant throughout all experimental work. The study was limited to two types of starches; regular and cationic, and two types of insolubilizers; melamine formaldehyde and glyoxal. The effect of adding some latex to the adhesive mixture, with respect to water resistance, was also explored. Data received substantiated the superiority of glyoxal over melamine formaldehyde in producing wet-rub resistance in starch base coatings. Calculated results also proved the merit of using a cationic starch, in conjunction with the insolubilizing additives, rather than a regular starch. However, data also showed that neither melamine formaldehyde nor glyoxal alone in a starch paste ever surpassed a starch paste with small amounts of latex added, with respect to water resistance. Finally, representative samples of all test coatings made were printed on an offset printing press. Single-pass printing quality of all sheets, irregardless of the coating mixture, was excellent. Multi-pass printing was not explored. The water resistance of all of the samples was sufficient to produce excellent printing quality with no signs of sheet curl