| Resumo: |
Sonae Indústria is world leader in the production of wood-based panels, being also a urea-formaldehyde resins (UF) producer. These resins are still the most widely used adhesives in the manufacture of wood-based panels, mostly due to their high reactivity, low cost and excellent adhesion to wood. The greater drawbacks are the low moisture resistance and the formaldehyde emission during panel manufacturing and service life. Although free formaldehyde of these resins have been decreased over the last decades, the recent reclassification of formaldehyde by IARC as "carcinogenic to humans", is forcing resin producers to develop systems that leads to a decrease of formaldehyde to levels as lower as natural wood. Until now, the decrease of free formaldehyde had been obtained by decreasing the molar ratio F/U, which leads to a decrease on reactivity and the degree of curing, with consequences in the formation of adhesive bonds. On the other hand, hardeners that are currently used are adapted to high molar ratios F/U and they do not work well at low ratios. So, the decrease of molar ratio F/U could result in lower internal bond panels and the target level of formaldehyde emission could not be attained.
We intend to develop gluing solutions "taylor-made", worldwide innovative, considering the operation scale of SONAE. The strategy to follow will include three approaches: optimisation of UF resin synthesis at laboratory and industrial scale; develop a broad spectrum of catalysis systems for UF curing and the combination of high performance urea-formaldehyde resins with added chemical formaldehyde scavengers. |