Tofu ingredient used to create formaldehyde-free plywood glue
August 27, 2010
Two thousand years ago Jesus may have walked on water, but soon we may be walking on food. In a bid to become more environmentally sustainable, scientists have unveiled a new "green" alternative to commonly used petroleum-based wood adhesives. Representatives from the U.S. Department of Agriculture (USDA) Forest Products Laboratory in Wisconsin, speaking at this week's 240th National Meeting of the American Chemical Society, talked about the development of a soy-based glue. The substance is derived from food products such as soy milk and tofu, and could mean a new generation of eco-friendly flooring, furniture, cabinets and other wood products.
This new adhesive uses soy flour, an additive commonly used to make paper water resistant. The adhesive is as effective as petroleum based glues, but without the harmful formaldehyde fumes (a potential carcinogen) released from traditional plywood, particleboard, and other composite products. Formaldehyde fumes may also cause short-term symptoms such as watery and burning sensations in the eyes, nose and throat, and skin irritation. Charles Frihart, Ph.D, who participated in the research project, said that such problems, combined with rising petrol prices and a strong movement towards sustainability, are encouraging wood manufacturers to take another look at soy. Many wood products today appear to be made of solid wood, however in reality they are often composites, comprised of wood pieces glued together with petroleum-based adhesives.
“Protein adhesives allowed the development of composite wood products such as plywood in the early 20th century,” said Frihart. “Petrochemical-based adhesives replaced proteins in most applications based upon cost, production efficiencies, and better durability. However, several technologies and environmental factors have led to a resurgence of protein, especially soy flour, as an important adhesive for interior plywood and wood flooring.”
A variety of soy based glues have been tested by academic, industrial, and government researchers in the USA. They have tested out the glues on wood samples placed under extreme conditions, including water exposure and high levels of heat. At the conclusion of the tests, a soy-based glue composed of soy flour and other modifiers yielded high results. The goal for Frihart and the team of researchers is now to formulate new soy based adhesives that are even stronger than the existing ones.
Soy-based adhesives currently make up less than five percent of the wood adhesive market. It is hoped that this study will help increase the use and presence of "green" adhesives across the world. The US Forest Service is currently developing the adhesives in partnership with Ashland Hercules and Heartland Resource Technologies.