Here’s an article at Wood & Wood Products Magazine describing a new type of glue made from soy flour that’s replacing the urea formaldehyde glues typically used in plywoods.
The urea formaldehyde glues are especially troublesome as they outgas formaldehyde into the living space. The new type of glue was made by Kaichang Li at Oregon State University who studied the adhesive mussels use to attach themselves to rocks. Li figured out how the adhesive works and set to developing a process that can modify soy proteins to have similar properties. The method is simple enough that he can do it in his kitchen mixer.
According to this month’s Journal of Light Construction (not yet online) the new plywood can be boiled for 20 hours, dried, and boiled again without delaminating. The standard test for outdoor plywoods is a 4-hour boil and today’s plywoods cannot survive the 20-hour test.
Columbia Forest Products has already switched its hardwood veneer plywoods over to the new adhesive and is investigating switching over its other plywoods. As urea formaldehyde is derived from fossil fuels, its price is expected to increase with oil.