A Formaldehyde-Free Bio-Adhesive for Plywood and Particleboards Based on Soy Flour, Magnesium Oxide and a Plant-Derived Enzymatic Hydrolysate

At present, the particleboard industry, which together with the plywood industry dominate the wood-based panels’ production volume worldwide, uses almost exclusively urea- formaldehyde (UF) resins . However, environmental sustainability and consumer demand for healthier products have contributed to an increase in research efforts to find substitutes for these petroleum-based thermosetting adhesives. Formaldehyde has been reclassified as a human carcinogen compound by the International Agency for Research on Cancer already in 2004 while a new classification entered into force for the European Union in June 2014 following the CLP (Harmonised Classification, Labelling and Packaging) Commission Regulation 2015/491. The discussion on both the availability of fossil resources for producing million tons of amino resins every year and the restrictions on formaldehyde emissions from the finished wood composite products is expected to intensify . The US Environmental Protection Agency (EPA)5 adapted the California Air Resources Board (CARB)6 emission limits in 2017 (EPA 2017), and formaldehyde in indoor environment is a current legislation topic in other places of the world. The latest example comes from Germany, where lowered legal limits for formaldehyde emissions (from the European emission level E1 of 0.10 ppm to 0.05 ppm) and a new proposed test method will come into effect as from 1st of January 2020 (Bundesministerium für Umwelt Naturschutz und nukleare Sicherheit 2018)