The demise of eco-friendly Woodstalk™ last December has producers pondering alternatives. Dow's product contained no-added formaldehyde, used surplus wheat straw fibre, machined easily and was manufactured in Canada. For furniture manufacturing the equivalent replacement panel is an eco-friendly, medium-density fibre board (MDF) - plywoods are expensive and have edge-sealing issues, as do particle boards. (See furniturelink's Buy Green for sources of non-MDF eco-panels.)
Made with a no-added formaldehyde adhesive, Medite II from SierraPine in Oregon is the established environment-friendly MDF panel on the market. Recently three alternative eco panels have been released - Patinna F4S, Arreis and Platinum. Each have positive and negative features (the table below lists properties and other data for all four panels). furniturelink undertook to evaluate them and presents the results in three categories - adhesives, certification/recycling and physical properties.
The three adhesive resins used in the manufacture of MDF (in order of common usage) are urea formaldehyde (UF), methylene dipenyl diisocyanate (MDI) and phenol formaldehyde (PF).
Urea formaldehyde - Panels are moderately water resistant . Controversy concerns their continous emission of small quantities of formaldehyde gas over the lifespan of the product, a gas that has been classed a probable carcinogen by the US Environmental Protection Agency (EPA). Because of this health threat and the green-house factor, the MDF panel industry worldwide has been actively reducing fomaldehyde emissions. In North America, industry sources have claimed the emission rates for "standard" UF MDF have been reduced from about 1.5 ppm in the early 1980s to the current target level of 0.3 ppm (or less) .
Comparing panels at Ornamentum Furniture, Vancouver.
The Patinna F4S panel's formaldehyde emissions at 0.05 ppm are 83 percent lower than the 0.3 ppm industry standard. It also meets the stringent Japanese building standards, which allows it to be used with no restrictions. The 0.05 ppm level will also meet the proposed year 2012 California Air Resources Board (ARB) formaldehyde emission standards for composite wood products.
Methylene dipenyl diisocyanate - Panels are very resistant to water and damp atmospheres  and contain "no-added" formaldehyde. Very low "background" levels may be emitted.
Often wood contains small quantities of formaldehyde naturally. As such, panels with test levels of 0.05 ppm or less can be considered to be at or close to natural "background" levels. To put this in perspective, the formaldehyde emission level certificate  for Medite II and Arreis (that both use MDI adhesives) states "Lab tested to less than 0.05 ppm (of formaldehyde)" - not that the emissions are zero. 
Phenol formaldehyde - Panels are very resistant to water and damp atmospheres  and may have very low "background" levels of formaldehyde emission. Although formaldehyde is present in the PF resin molecule, it is far less prone to hydrolysis (break down) than the formaldehyde in the UF resin molecule. Platinum, the only panel of the four made with PF resin, is a new development for the manufacturer, so its listed properties are still to be reviewed .
Most MDF (including "standard" grades) is made from recycled wood waste produced by mills and manufacturing plants. SierraPine adds that it uses recycled "pre-consumer" fibre sourced from forests with Sustainable Forestry Initiative (SFI) certification for its Arreis and Medite II panels. SFI certification is not recognized by the LEED (Leadership in Energy and Environmental Design) green building rating system. LEED recognizes the Forest Stewardship Council (FSC) certification awarded to the Patinna F4S and Platinum panels.
The Meridian Institute provides a balanced analysis of the SFI and FSC certification systems.
|Physical Properties and Other Data of 3/4" MDF Panels |
|Property||Unit||Patinna F4S||Medite II||Arreis||Platinum |
|Modulus of rupture||lb/in²||6,500||5,000||5,200||6,500|
|Modulus of elasticity||b/in²||508,000||500,000||520,000||507,600|
|Modulus of hardness||lbs (janka)||n/avail.||1,150||1,150||n/avail.|
|Moisture content||% (oven dry)||8.0||3.0 - 6.0||4.0 - 6.0||6.5|
|Thickness tolerance||in||+/- 0.005||+/- 0.005||+/- 0.005||n/avail.|
|Adhesive ||UF||MDI||Modified MDI||PF|
|Formaldehyde ppm ||0.05||||||0.05|
|Fibre content certification||100% FSC||100% SFI||100% SFI||100% FSC|
|Country of origin||New Zealand||USA||USA||New Zealand|
The above chart shows that the four panels are almost equal in density and modulus of elasticity (stiffness). Patinna F4S and Platinum have higher modulus of rupture values. Patinna F4S has the lowest internal bond strength (lowering the formaldehyde levels can result in lower bond strength), which may involve some design constraints.
Grant Wyllychuk, owner of FSC chain-of-custody certified Ornamentum Furniture in Vancouver, BC, ran some simple machining "tests" on small samples of Patinna F4S, Arreis and Medite II (see above). Tests included bandsaw and tablesaw cuts, routered dados and biscuit slots. Although there were minor variations in performance, Wyllychuk found no substantive difference in the three panels' machinability.
While waiting for new agriboard panels to become available, furniture designers and makers can use the MDF panels listed here or substitute a different format of wood-based panel from the furniturelink list of buy green.
 Based on ASTM Test E-1333 (large chamber)
 Data from specification sheets of manufacturers; see also 
 Data for Platinum based on early estimates and do not guarantee actual results
 UF = Urea formaldehyde, MDI = Methylene dipenyl diisocyanate, PF = Phenol formaldehyde
 An estimate of panel price comparison, where Medite II equates to 100 percent
 SCS certificate states, "Lab tested to less than 0.05 ppm" (see  below)
 Update (2013) the SierePine Arries and Medite II MSDS now states "manufactured with no added formaldehyde"
 In 2013 minor edits were made to the paragraph for clarity
© furniturelink 2006 (text and images)