Summary

Accoya™ wood is a “new wood species”, whose performance credentials have been extensively researched and repeatedly demonstrated. Accoya™ wood has properties that surpass those of the best tropical hardwoods, yet is manufactured using a non-toxic process and wood from certified sustainable sources.

How is it used

This wood material is suitable for cladding, siding and façades where aesthetics, less frequent maintenance, dimensional stability, durability and insulation value are key factors. Accoya™ wood’s versatility makes it ideal for use in residential, commercial and industrial structures. This material is already being considered for new and exciting applications. It is imagined to have use in boat decks and trimmings, tree houses, noise barriers, musical instruments, signage, veneers, high durability particleboards and fiberboards.

Accoya™ wood has been shown to deliver performance that exceeds that of even the most durable tropical hardwoods. It is ideal for exterior applications such as doors, window frames, garden decking, façades, cladding and sidings, boat decks and garden furniture where exposure to the elements means that dimensional stability, durability and UV resistance are important.

In Holland, for example, acetylated wood was used as a canal siding and removed after 10 years’ exposure to water without showing any signs of degradation.

How is it made

The technology behind Accoya™ wood is based on wood acetylation, a process that has been studied by scientists for more than 75 years and proven to be an outstanding method of improving the technical properties of wood. The process essentially alters the actual cell structure of wood by transforming free hydroxyl groups into acetyl groups. Acetyl groups simply consist of hydrogen, oxygen and carbon and are already present in all wood species (ranging from 1% to 8% by weight) and can be derived independently from acetic acid, i.e. vinegar. Thus, the process does not introduce anything to the wood that does not naturally occur in it.

Technical specifications

Unmodified wood has ‘free hydroxyl groups’ that absorb and release water as climatic conditions change, making it prone to expansion and contraction, particularly when used outdoors (windows, doors, cladding, etc), which in turn leads to splitting and rotting.

During the Accoya™ wood production process, the free hydroxyl groups within the wood are changed into acetyl groups and this reduces the ability of the wood’s cell walls to absorb water by approximately 80%, greatly improving the wood’s dimensional stability and resulting in reduced maintenance frequencies for coatings.

In addition, the change in cell structure means that fungi do not recognise Accoya™ as wood and therefore do not attack it. Insects that attempt to eat the wood die of starvation because the modified structure makes it indigestible, so that it is no longer a source of food.

Due to the improved dimensional stability of Accoya™ wood (significantly reduced swelling and shrinking), maintenance of the coating system can be increased to 10 to 15 years (3 to 5 years is the average for unmodified wood under normal circumstances). Close collaboration with Sikkens, part of the world’s leading paint company Akzo Nobel, has resulted in a package of guarantees for windows and doors, including 30 years in conjunction with the Sikkens Sentinel Plus Wood Maintenance Protection Programme. In addition, extensive tests have shown better coatings adhesion and reduced costs in applying coatings in a manufacturing environment.