Banner for LabNotes
From Lab Notes
Contact Information
Forest Products Laboratory
One Gifford Pinchot Drive
Madison, WI 53726-2398
Phone: (608) 231-9200
Fax: (608) 231-9592


You are here: FPL Home  / Information Products & Services  / Publications

Requested Product

Title: Dispersion adhesives from soy flour and phenol formaldehyde

Source: Proceedings : 30th annual meeting of the Adhesion Society, Inc. : February 18-21, 2007, Tampa Bay, FL. [S.l. : s.n.], c2007: pages 150-152.

Author(s)Frihart, Charles R.; Wescott, James M.; Traska, Amy E.

Publication Year: 2007  View PDF »

Category: Journal Articles

Abstract: Higher petroleum prices and greater interest in bio-based adhesives have stimulated a considerable amount of research on incorporating soybean flour into wood adhesives in recent years. In some cases, soy was used at low levels as an extender for phenol-formaldehyde (PF) adhesives; in other cases, highly hydrolyzed soy flour was used. Although progress was made in getting soy to react with PF, incorporation of the soy was still fairly low. Addition of the flour to hot aqueous caustic, followed by stabilization of the alkaline soy mixture by reaction with formaldehyde, was a recent key step toward higher incorporation of soy flour in PF adhesives (1). These conditions provided an ideal protein structure to allow the reaction of phenol and formaldehyde with functional groups on the protein while minimizing undesired hydrolysis of the protein backbone. Good performance was obtained using nearly equal quantities of soy flour and phenol-formaldehyde resin for the face adhesive in producing strandboard (1). A ratio of 40% soy to 60% PF resulted in an adhesive with performance equal to that of a commercial PF face adhesive in both cure speed and final properties of the resultant strandboard (2). A limitation on soy flour incorporation in these adhesives may be caused by the slow curing reactions of the hydroxymethylamine groups on the protein under basic conditions. Amino resins cure slowly under alkaline conditions but work well under acid cure conditions (3). Therefore, the question was whether an acidic soy-PF resin can be made and whether this would allow for higher soy contents in the adhesive. Soy flour consists mainly of proteins (41-48%) and soluble and insoluble carbohydrates (30-40%), along with some other minor components. The protein in its native state is only moderately soluble, but treatment with caustic is known to increase the solubility of soy protein by increasing the net charge of the proteins. Acidification to pH 4-6, near the isoelectric point of many soy proteins, generally leads to precipitation of much of the protein. Likewise, the phenolic resins are usually soluble in aqueous caustic and precipitate out upon acidification to pH 4-6. This research was aimed at trying to make stable acidic mixtures of soy-PF resins with high soy contents that could be readily applied to and bond wood flakes to make strandboard.

Keywords: Particle board, soy flour, adhesives, soybean glue, formaldehyde, phenolic resins, OSB, oriented strandboard, durability, bonding, phenolic adhesives, phenolic resin glues

File size: 305 kb(s)

This publication is also viewable on Treesearch:  view
RITS Product ID: 21118
Current FPL Scientist associated with this product
Frihart, Charles R.
Research Chemist

Additional items that might interest you
View the video celebrating FPL's 100 years of public service in 2010, from the producers of the Greatest Good....view

Research Highlights from FPL....view

Termite Eradication: A search for the Holy Grail.... view

Moisture Management in Residential Construction Series videos...view

Wood Floor Systems in Residential Construction Series videos....view
- FPL's Mission and Strategic Plan -

FPL's mission is to identify and conduct innovative wood and fiber utilization research that contributes to conservation and productivity of the forest resource, thereby sustaining forests, the economy, and quality of life. ... ..more »

- FPL Research Emphasis Areas -
Advanced Composites

As an integral part of the FPL mission, we improve the long-term sustainability of our Nation's forests by creating valuable composite products from biobased materials ... ..more »

Advanced Structures

The FPL has been in the forefront of wood-frame housing research since 1910 and has long been recognized as a world leader in such housing-related areas as engineered wood ... ..more »

Forest Biorefinery

We all know the compelling reasons that the United States needs to reduce its dependence on fossil fuels. Historically, the greatest increases in energy demand have been for transportation fuels ... ..more »


A leader in wood products research for over a century, the FPL is positioning itself to become the lead Federal research facility for the application of nanotechnology in forest products ... more »

Woody Biomass Utilization

Forests in the United States contain a substantial amount of small-diameter, overstocked, and underutilized material.FPL research projects are exploring the potential of the small-diameter ... ..more »