Isocyanates as Wood Binders—A Review

The chemistry of isocyanate reactions is reviewed. Theories on the mechanisms for reactions with wood are developed. The reactions of isocyanates with various reactive sites on wood are offered as the most probable explanation for the excellent bonding efficiency of isocyanates in particleboard. Experimental evidence is cited which suggests that the formation of polyurea compounds provides the necessary link between urethane-to-wood anchored MDI molecules.