Wood without preservatives

Traditional wood preservatives may contain active ingredients such as copper, boron, phosphorus, and creosote. These work by decaying fungi and other organisms that attack the wood. Environmental authorities have drawn attention to the various environmental and health problems caused by these wood preservatives.

Some ingredients have subsequently been banned and others are classified as pesticides, where their use requires special precautions. There is therefore considerable interest in the development of more environmentally friendly alternatives.

“OrganoWood is a whole new way to protect wood from decay and fire,” said Mårten Hellberg, CEO of OrganoWood AB. “The advantage of our modified hardwood is that it contains no biocides or heavy metals. An added bonus is that our wood is flame retardant and maintenance free.”

“Our technology is inspired by the natural fossilizing process,” said Juhanes Aydin, director of product management at OrganoWood. “In nature, fossilization takes a very long time, but we increase the speed by a chemical process called organic catalysis. We use small natural substances that catalyze the reaction in which silicon is bound to the cellulose molecules. The catalyst is found in fruits and vegetables and our preservative fluid is water-based and contains no substances that are classified as hazardous.”

OrganoWood based its technology on research and development performed by OrganoClick AB. The company, founded in 2006, develops methods for the modification of cellulose-based materials such as paper, wood and textiles. The basic idea is that by using “green catalysts” at low temperatures one can bind chemicals to the cellulose molecules. This results in completely new properties in the wooden materials. You can read more about this in the article “Green cellulose chemistry provides environmental benefits.”

Cellulose molecules have novel properties

The use of small organic molecules as catalysts has already been used in the pharmaceutical industry, but if applied to cellulosic materials such as wood, textiles and paper, many interesting possibilities open up.

Professor Armando Cordoba at the Mitt University in Sundsvall, Sweden and Associate Professor Jonas Hafrén at the University of Agricultural Sciences in Uppsala, also in Sweden, were inspired by drug manufacturing. The two professors developed the new environmentally friendly method for wood.

“In the timber, silicon binds itself to cellulose molecules and the result is a physical barrier to decay, “said Mårten Hellberg. “Rotting agents no longer see the wood as a nutrient, and a piece of wood that has been buried in the ground for three years shows no infestation of dry rot. The mineralization also makes the wood resistant to fire in an excellent manner.”

“Wood treated with our technology consists of approximately 10 percent silicon and the rest is wood. Fossilization occurs primarily on the surface of the fibers, which encapsulates them and makes them inaccessible for decaying fungi. Our wood has undergone tests for rot and fire protection with very good results. When the timber reaches the end of its life, it need not be treated as hazardous waste but can be reused for something else,” said Hellberg.

“The modified wood can be used for patio decking and terraces but an entire house can also be built with it. The wood has a natural color and may in time develop a silver gray tint with a hard and even surface increasing the wood’s life even further.”

"The technology is completely inspired by the natural fossil process"

Wood treatment on an industrial scale

OrganoClicks facility in Täby, outside of Stockholm, has the capacity to produce approximately 7,000 cubic meters of wood preservative annually. The silicon in the preservative comes from sand and rice husks whereas the catalyst is derived from fruits.

The wood is chosen from selected suppliers and cut to the correct dimensions and profiles. Modifications are carried out by Bergs Timber Bitus AB in Nybro. Their wood treatment facility is the largest in Sweden and has an annual capacity of
300,000 cubic meters.

OrganoClicks has a dedicated production line for manufacturing modified wood for OrganoWoods. The modification process begins when the preservation fluid is literally pushed into the wood down to its core. After drying the wood in a specially developed process, the silicon compounds and wood grain further react with each other. After quality control and packaging, the timber is finally ready to be delivered.

… And for domestic use

The preservative liquid can also be used as a surface treatment for untreated wood and is available in cans. Examples include the treatment of wood like spruce and pine, and products composed of chipboard, plywood and fiberglass. The treatment yields good rot and flame resistance but industrially pre-treated materials may give more complete coverage.

article was published in June 2012