Sustainable non-isocyanate polyurethanes bio-adhesives for engineered wood panels are revealed as promising candidates to move from formaldehyde-based alternatives

The main driving forces on the development of eco-friendly wood adhesives are based environmental sustainability, costs savings, recyclability, reusability and health benefits, in comparison with synthetic resins. Lignin, tannin, proteins carbohydrates renewable raw materials being studied. Taking as a premise technical performance different bio-based alternatives, formaldehyde-based resins, it is necessary to evaluate profile such products order assess pros cons. In this regard, manuscript addresses industrial-scale design evaluation, through Life Cycle Assessment methodology, four formaldehyde-free bio-adhesives. For purpose, use resources Organosolv (OSL) kraft (KL) lignins, soy (SPI) tannins (MT)), crosslinked hardened NIPU (non-isocyanate polyurethanes) were considered. impact results obtained showed that OSL-NIPU bio-adhesive, single score 35.27 mPa, has best profile, followed by SPI-NIPU, value 63.36 mPa. Therefore, both could be considered potential substitutes for On other hand, been identified hexamethylenediamine (HDMA), used crosslinking agent formulation bio-adhesives, one hotspots profiles OSL, KL MT case SPI-NIPU adhesives, protein isolation process leads higher contribution. Thus, future research should focus trying reduce dose HMDA improving process.