Soy flour has been used as a wood adhesive for a long time, but its popularity decreased with the rise of synthetic resins. However, by adding a special resin called PAE, the strength of soy adhesives has improved, leading to a comeback in their use. The way soy products are processed affects how well they work as adhesives. Soy protein isolate, which undergoes a specific heating process, is particularly good at making strong wood adhesives, especially when combined with PAE.