Distillers’ grains used as a filler in recycled containerboard

Distillers’ grain (DG) was used as an ingredient in paperboard made in the laboratory from recycled containerboard fibers. The chemical composition and physico-chemical properties of DG fractions that had been isolated using varied screens were investigated. The effect of DG incorporation on the properties of the recycled paperboard was compared relative what was obtained with either precipitated calcium carbonate (PCC) or talc powder as fillers. The DG was found to mainly contain cellulose, hemicellulose, lignin, protein, and fat. At a filler addition level of 5%, the 100- to 140-mesh DG-filled handsheet exhibited the most satisfactory physical properties, with a tensile index of 25.4 N·m·g-1 and a ring crush index of 7.95 N·m·g-1. The strength values were generally higher than those of paper filled by PCC or talc powder at the same addition levels. The tensile index and ring crush index of hybrid-filled handsheets increased with increasing ratios of DG. The results suggest that DG can be used as a substitute for fiber content in some grades of paperboard, especially where a low-cost, bulky material could provide an advantage. Such usage of DG can resolve environmental challenges associated with storage and transportation of excess DG that is presently discarded.