ADHESIVE QUALITIES OF SOYBEAN PROTEIN-BASED FOAMED PLYWOOD GLUES

Authors: Hojilla-Evangelista, Milagros - Mila

Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/25/2002
Publication Date: 11/1/2002
Citation: HOJILLAEVANGELIST, M.P. ADHESIVE QUALITIES OF SOYBEAN PROTEIN-BASED FOAMED PLYWOOD GLUES. JOURNAL OF THE AMERICAN OIL CHEMISTS SOCIETY. 2002. v. 79. n. 11. p. 1145-1150.

Interpretive Summary: Foam extrusion is a method of applying glue to plywood in which glue is foamed with air and then extruded in parallel strands (called "noodles") onto veneers that pass under the extrusion head. Glues for foam extrusion contain a protein extender, which is currently animal blood. Current concerns about the potential of animal blood to harbor disease-causing agents, as well as its limited supply and storage stability, have prompted the search for alternate protein extenders. This research was conducted to determine if soy proteins can replace animal blood in foamed glues. We found that standard foamed glues containing the soy flours ISU-CCUR, Honeysoy 90, Nutrisoy 7B and defatted Soyafluff, and soy concentrates Arcon F and Procon 2000 had good mixing and foaming properties and excellent bonding strength, but poor re-foaming ability. We found that re-foaming capability can be improved markedly by increasing the amount of soy flour or concentrate in the glue mix so that the soy product provided the same amount of protein as did animal blood. The soy-based modified foamed glues had adhesive strengths that were equal to that of the control glue. Modified formulations were found to be cheaper than the current blood-based glue when soy flour is used. Using soy flour in foamed plywood glues will result in a less-costly, environmentally-friendly adhesive; the production of which will consume up to a half-million bushels of soybeans per year, thus generating additional income to soybean growers in the United States.

Technical Abstract: A study was conducted to evaluate the potential of soy protein-based plywood glues for foam extrusion. Standard glue mixes containing the soy flours ISU-CCUR, Honeysoy 90, Nutrisoy 7B and defatted Soyafluff, and the soy concentrates Arcon F, ISU-CCUR, and Procon 2000 showed excellent foaming and adhesive qualities, but did not have the ability to re-foam. To improve re-foaming capability, soy protein-based foamed glues were modified by using protein content-based replacement of animal blood by soy protein. All the modified glues containing soy flour or concentrate had good re-foaming properties and adhesive strengths that were at least equal to that of the control glue. Simple cost analysis also indicated that the modified formulations were cheaper than the current blood-based glue when soy flour is used.