Customary flame-retardant solutions are based on intumescent coatings on the basis of melamine-formaldehyde resins. These, however, must be critically evaluated in indoor areas as a result of the potentially carcinogenic formaldehyde emissions. Furthermore, some of the solutions currently in use cause unsightly efflorescence, loss of the durability of the fire-protection effect and, in the worst case, loss of strength due to wood degradation as a result of released acids. Moreover, conventional flame-retardant coatings are based on petrochemical raw materials.
We develop transparent and colored flame-retardant coatings for solid wood, veneer-based materials (molded parts, laminated veneer lumber, plywood) and other wood-based materials which are utilized in interior construction. Both the binder and the flame retardant should have a renewable raw-material content of at least 50 percent. In addition, they should not contain any saline additives. Our aim is to make furniture and construction products made from wood “flame retardant” through the application of our flame-retardant coating.
As the starting materials for the new binder, both established and new bio-based monomers are utilized, such as saccharides. Using these binders, we produce formulations with a fire-retardant effect. The group of substances containing alkoxyamines and alkoxyimides is already being successfully applied as flame retardants for plastics. We are investigating their applicability in wood coatings and are conducting research to determine whether these substances can be synthesized from bio-based building blocks. A further advantage: The utilization of alkoxyamines and alkoxyimides requires smaller quantities of flame retardants than intumescent coatings and other conventional solutions.
The flame-retardant coating should not contain a formaldehyde source or have any other negative effects on indoor-air quality. In terms of resistance to chemicals, abrasion and scratching, it should be able to compete with commercially available products for furniture and interior construction.
We are testing the new flame-retardant coating on traditionally widely-used softwoods such as spruce, pine and larch, as well as on hardwoods such as beech and poplar as these will play a greater role in the future due to climate-related forest restructuring.
Fraunhofer Institute for Wood Research 
