Dialdehyde Starch in Paper Coatings Containing Soy Flour‐Isolated Soy Protein Adhesive

Abstract

Abstract A combination of soy flour and isolated soy protein was investigated as the adhesive in pigmented paper coatings that contained dialdehyde starch (DA) as the insolubilizing agent. A coating formula of 50% solids made up of 8.3 parts soy flour, 8 parts isolated soy protein and 0.5 part DAS per 100 parts of clay exhibited pseudoplastic and thixotropic flow properties characteristic of coating colors containing more costly protein adhesives. Both was pick and wet‐rub resistance of the paper coating were improved and putrefaction retarded by the use of DAS in the formulation. Brightness, was pick and wet‐rub resistance values compared favorably with those of a reference coating containing 12.5 parts of isolated soy protein and 0.5 parts DAS per 100 parts of clay.