Treating Wood with Acetylation Process
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The IWF debut of Accsys Technologies’ Accoya wood, which is warranted to resist decay,
took place in Atlanta in August.

Making its debut at the International Woodworking Fair in August was Accoya “high-technology wood.” Manufacturer Accsys Technologies demonstrated Accoya wood treated with a modification process that it says differs from other modified woods. Calling it “transformed to its core” Accsys says Accoya uses an acetylation conversion process that allows woodworkers to machine, coat and glue it like “normal” wood, with a durability and dimensional stability that matches or exceeds even that of tropical hardwoods.

Accsys says the acetylation process used for Accoya has been studied by scientists around the world for more than 75 years. The science runs like this:

Accoya wood was adopted by Riverstone Cabinet for a
new outdoor line and also was used for exterior screens
by the University of Florida in an international competition.
Physical properties of any material are determined by its chemical structure. Wood contains an abundance of chemical groups called “free hydroxyls,” groups that adsorb and release water according to changes in the climatic conditions to which the wood is exposed — the main reason why wood swells and shrinks. Scientists believe that the digestion of wood by enzymes initiates at the free hydroxyl sites — which is one of the principal reasons why wood is prone to decay. Acetylation changes the free hydroxyls within the wood into acetyl groups, by “reacting” the wood with acetic anhydride, which comes from acetic acid — the main ingredient in vinegar. In layman’s terms, the wood is “pickled.” This reduces the wood’s ability to absorb moisture, rendering the wood more dimensionally stable and, because it is no longer digestible, extremely durable.

Accsys says its Accoya wood is made from sustainably grown sources and offers performance advantages where exposure to the elements is a concern, including decking and exterior furniture and cabinetry, windows, doors, cladding and structural-components.

“Accoya is the world’s most stable wood, resulting in a significant reduction in cup, bow, twist and cracks — making it perfect for wood working applications in any climate,” says Lisa Ayala, sales manager for North America. “We warranty Accoya wood for 50 years in exterior above-ground use and 25 years in-ground.”
In Europe, where it was first offered, Accoya also has been used to build bridges, planters and garden furniture. Accoya is available throughout North America through a network of independent distributors.

Riverstone Cabinet Co. says it is using specially treated Accoya wood in a new outdoor line of kitchen cabinetry, planters, benches and tables. Riverstone Cabinet says Accoya was selected due to its high performance and ability to withstand extreme weather conditions.

“We chose Accoya wood because it offers exceptional dimensional stability and durability,” said Kim Galazen, CFO at Riverstone Cabinet, St. Cloud, MN. “Now that we’re in production, we’re finding that Accoya wood is easy to work with, lightweight and doesn’t twist, cup, or bow when being machined,” she said. “It is also very easy to coat, which keeps us operating efficiently.”

According to Galazen, “Outdoor spaces are an extension of the home and most people who spend a lot of time outdoors would like alternatives to the plastic furniture dilemma. Using Accoya wood for our new series is enabling us to offer customers a beautiful long-term, low maintenance solution,” she said.

Accoya wood also was used for adjustable exterior screens in the University of Florida’s Solar Decathlon Europe house-design competition entry, entitled “Project RE:FOCUS.” The design for the zero-energy house used back-to-basics energy conservation technology and the screens allowed homeowners to use natural daylight and cut energy consumption.

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