Soy-Based Adhesives Mussel Out Formaldehyde to Meet New Regulations

Some time ago, the International Agency for Cancer Research reclassified formaldehyde from a suspect carcinogen to a known carcinogen. With United Soybean Board (USB) support, Kaichang Li, an associate professor of wood science and engineering at Oregon State University, developed a soy-based formaldehyde-free resin that bonded wood like a mussel to a wet rock.

The technology was commercialized, resulting in the sale of more than 50 million formaldehyde-free plywood panels under the brand PureBond^®.

New rules proposed by the Environmental Protection Agency (EPA) are giving researchers and manufacturers an even greater incentive to think soy. The proposed EPA rules set limits on how much formaldehyde may be released from engineered woods. The rules cover hardwood plywood, medium-density fiberboard, particleboard and finished goods containing urea-formaldehyde (UF)that are sold, supplied, offered for sale or manufactured in the United States or those imported into the country. This covers products ranging from wood paneling and home furnishings to glues, pastes, antibacterial items, shampoo, paper towels, paper stickers, phenolic resins and urea plastics used to make things like buttons and shoes.

A second proposal establishes the requirement of a third-party certification to ensure manufacturers of composite wood products meet Toxic Substances Control Act (TSCA) formaldehyde-emission standards. The emission standards are identical to those currently in place under the California Air Resources Board Airborne Toxic Control Measure.

The Science of Soybeans Unlike petrochemical-based wood adhesives,soy-based formulations reduce the release of volatile organic compounds. Soy flour has also proven to be an ideal raw material for making wood adhesives because it is abundant and usually costs less than petrochemicals. The relatively low cost of soy meal/flour versus petrochemical-based products has added value for manufacturers.

Although urea and phenol formaldehyde have not been completely replaced by soy in all wood adhesives, even a partial replacement can represent large cost savings. As concerns about environmental exposure to formaldehyde continue to surface, cost-competitive, versatile soy-based wood adhesives are the natural choice in adhesive formulations.