STRUCTURAL TANNIN-BASED LUMBER END-JOINT ADHESIVES FOR EXISTING PRODUCT LINES.

ONE OF THE HIGHEST DEMAND WOOD PRODUCT APPLICATIONS ARE LAMINATED BEAMS. AT PRESENT, THE STRUCTURAL-QUALITY END-JOINTING OF THE LUMBER FOR PROVIDING ESSENTIALLY ENDLESSRIBBONS TO BE USED AS PLIES (AFTER CUTTING TO PROPER LENGTH) IS DONE IN NORTH AMERICA BY USING THE COMBINATION OF1. AN ADHESIVE BASED ON A) RESORCINOL; OR B) MELAMINE AND 2. RADIO FREQUENCY ENERGY TO ACHIEVE RAPID CURE. RESORCINOL ADHESIVES HAVE EXCELLENT DURABILITY BUT ARE EXPENSIVE AND OIL DERIVED. MELAMINE ADHESIVES HAVE LIMITED DURABILITY UNDER ADVERSE EXPOSURE CONDITIONS. TANNIN HAS RESORCINYLIC/PHENOLIC CHARACTER. PREVIOUS WORK (+)) HAS CLEARLY SHOWN TANNIN'S CAPABILITY TO BE USED IN COMBINATION WITH RESORCINOL ADHESIVES. THE PROPOSED WORK IS AIMED AT: 1. DEVELOP A TANNIN-RESORCINOL END-JOINT ADHESIVE SYSTEM FOR RADIO-FREQUENCY CURE. BENEFITS WILL BE HIGH DURABILITY AND LOW COST. 2. EXPLORE TANNIN-MELAMINE COMBINATIONS. IF SUCCESSFUL, ANTICIPATED BENEFITS WILL BE SUBSTANTIALLY IMPROVED DURABILITY AND LOWER COST. 3. EXPLORE TANNIN-UREA COMBINATIONS. THERE IS REASON TO BELIEVE THAT COMPOSITIONS OF THIS TYPE MAY ACHIEVE NEAR-EXTERIOR DURABILITY, PROVIDING THE CHEMISTRY OF THE SYSTEM ALLOWS INCORPORATION OF TANNIN UP TO 50 OR 60%.