The annual production of particleboard and medium density fibrebroad in the EU amounts to some 26 million m3, mostly bonded with urea-formaldehyde adhesives. As the adhesives cost from 20-30 % of the final product costs, they are crucial in determining profitability in a highly competitive industry. Urea-formaldehyde bonded products emit formaldehyde in service. The health effects of this substance has led to regulations limiting in emission (it must be lower than 6.5 mg/100 of board of Germany). Alternative adhesive-routes proposed were not able to solve the problems of health risk, high production cost and impaired board performance. In parallel, another problem of wood-based panels has always been their poor preservation.
The main objective of this project is the development of a low to zero formaldehyde
emission aminoplastic resin of improved weather an biological resistance to be used in the production of medium density fibreboard (DMF), particleboard and other wood-based panels. The synthesis route of such an adhesive, the parameters of its manufacture as well as its application conditions in panels production will be determined and optimised.
The process of this project addresses all the above problems by using the following
- copolymerization of the aminoplastic resin with long chain aliphatic primary
diamines/triamines and polyamines (nylons), in order to improve the water
resistance and lower the formaldehyde emission of the resin;
- resin cross-linking by the use of hexamethylenetetramine in the presence of natural and synthetic colloids to further reduce the formaldehyde emission and;
- incorporation in the adhesive of an easily diffusable non-toxic preservative such as boron, to improve board resistance to fungal attack.
The combination of these principles with already established technology and practices for low formaldehyde emission aminoplastic resins will be used to synthesise the new resins and test their behaviour in the production of lab scale panels. The best resin system obtained will be optimised regarding its manufacturing parameters and application conditions. The biological testing on the boards produced will be carried out in parallel. Pilot scale tests will follow in order to transfer the new technology to the semi-industrial level and to verify the lab results.
The production of resins capable of imparting to the wood-based panels and more
particularly to MDF improved water/weather resistance, very low to zero formaldehyde emission as well as biological resistance will be realized using an environmentally friendly process. This will be ensured by :
- the use of natural colloids in the reaction of the resin with hexamethylenetetramine;
- the incorporation of a non-toxic preservative;
- the aim to produce a resin with zero formaldehyde emission.
Funding SchemeCSC - Cost-sharing contracts
88051 Epinal Cedex 9