Starch based polyester type water resistant wood adhesive

Corn starch is one of the most adaptable and renewable industrial raw materials since it is abundant and easy to be separated. A process for manufacturing water resistant corn starch based and formaldehyde-free wood adhesive included four steps: corn starch was denatured by solid phase oxidation to produce oxidized corn strach. The oxidized corn starch was rapidly liquefied by ethylene glycol under ambient atmosphere at 110-140℃ to produce starch based polyol with high reactivation. Then the starch based reactive polyol was crosslinked with equivalent multicarboxylic acid (anhydride) through the ester bond. And pre-polymerized polyester type wood adhesive was diluted by absolute ethanol to prepare the sprayable wood adhesive. The resulting adhesive performed well as a formaldehyde-free wood adhesive. Multi-ply wood composites bonded with this polyester type adhesive had acceptable shear strengths and water resistance.