In part one of this series, we took a look at the mixed results when agricultural fibers were substituted for wood fibers in the manufacture of composite wood panel products, such as particleboard and medium-density fiberboard. We also saw how efforts are being made to substitute non-added formaldehyde) binders in lieu of formaldehyde (CH2O)-the standard binder (adhesive) in wood panel products.

In part two, we examined how the advent of "tight construction" has contributed significantly to indoor air pollution while, at the same time, it has increased energy efficiency significantly making it a double-edged sword. As well, we discussed a new commercially available particleboard from Roseburg Forest Products called SkyBlend and how it makes use of phenol formaldehyde rather than standard urea formaldehyde as a binder thus reducing considerably the harmful effects of formaldehyde off gassing into the indoor environment. This month, we'll review the NAF composite wood panel products available on the market.

Daring duo

Per Construction Specifications Institute section 06401, there are basically two types of composite wood-fiber-based panel board products:

• Medium-density fiberboard
• Particleboard

  Medium-density fiberboard is manufactured from the waste produced by lumber mills (sawdust). Standard MDF uses a UF binder that off-gases formaldehyde at fairly high levels-exacerbating the effects when used for interior products, such as cabinetry and paneling, whereby modern tight-building techniques contain and circulate volatile organic compounds, such as UF if not properly ventilated to the exterior. Acutely aware of this problem, some manufacturers offer formaldehyde-free MDF whereby an MDI (polyurethane) binder is used in lieu of UF. Typically, these environmentally friendly alternatives use Forest Stewardship Council certified wood content or are manufactured from recovered waste fiber, such as sawdust rendering it 100-pecent recycled content.

  Particleboard is made from larger wood fiber particles than the wood fiber "dust" used for manufacturing MDF. This gives particleboard a lower density than MDF (which is "medium density") but it does not mill as cleanly as MDF does. Environmentally friendly particleboard products typically use low or zero formaldehyde, FSC certified wood and/or Ag-fiber as a substitute for wood fiber.

  
  
  

  Alike but different

  SkyBlend is a good example of a "low" off-gassing formaldehyde particleboard product since it uses PF rather than UF as a binder-but it does not use FSC certified wood fibers or Ag-fiber as a substitute for the post-industrial mill waste of the lumber industry. Rodman Ind., of Oconomowoc, Wis., (www.rodmanindustries.com) offers Resincore1 particleboard. Like SkyBlend, it uses PF rather than UF as a binder, thus it has many of the same environmental benefits and performance characteristics as UF particleboard. However, Resincore1 uses FSC certified sources for its wood fibers and can/will customize the product's properties per the end user's specifications. Unlike SkyBlend, which is marketed commercially for general use, Resincore1 is a high-strength specialty particleboard product intended for a niche market. Because of its environmental benefits, the USGBC's LEED green building rating/certification program recognizes Resincore1 for indoor environmental quality LEED credits:
  
  • IEQ Credit 3: Construction IAQ Management Plan
  • IEQ Credit 4: Low-Emitting Materials
  
  
  

  Waste Not, Want Not

  A good example of a particleboard product which is both formaldehyde-free and wood-fiber free is PrimeBoard. Manufactured by PrimeBoard Inc., of Wahpeto, N.D., (www.primeboard.com), it was the first American National Standards Institute M3-rated particleboard made from wheat-straw and a formaldehyde-free binder. Available in a wide-range of thickness, size and grade, it is made from a blend of Ag-residue fibers. Custom-cut panels are available, as well as pressed panels with all-paper-based laminates, in a wide-range of colors. For its environmental attributes, PrimeBoard LEED credits include the same IEQ credits as Resincore1 and two Materials & Resources (MR) credits:
  
  • MR Credit 4: Recycled Content
  • MR Credit 5: Rapidly Renewable Materials

  Note: In late 2005, Masonite Inc. purchased PrimeBoard. Masonite intends to use the plant's output of straw-based particleboard for door-cores.

  Achieving all of the same LEED credits as PrimeBoard, Dow BioProducts, a wholly owned subsidiary of Dow Chemical Canada, marketed the product Woodstalk, which was made from straw (Ag) particles and used a formaldehyde-free PMDI (methyl diisocyanate) binder. Also, like PrimeBoard, Woodstalk met the ANSI-M3 standard for composite panelboard and was available in panel thickness' ranging from 1/4 to 11⁄8 inch and panel sizes of 4 feet by 8 feet, and 4 feet by 12 feet and 5 feet by 8 feet. After Dow's purchase of Isobord Enterprises, manufacturer of Isobord, they renamed the product Woodstalk. In 2004, Dow BioProducts produced 100 million square feet (9.3 million square meters) of Woodstalk.

  In early December 2005, Dow BioProducts ceased producing Woodstalk. With 50 percent of the manufacturing cost for energy and raw materials and a glass ceiling on price escalations, increases in the cost of oil and natural gas in the year-and-a-half preceding the December 2005 closing sealed Woodstalk's fate. On the bright side, Woodstalk was a well-liked product with an increasing market-share accepted by architects, specifiers and end-users. Way back in 1995, there were 12 straw panel manufacturers: two foreign and 10 domestic (of which only two are still in production). In the intervening decade (between 1995 and 2005), nine new strawboard manufacturers appeared but only four of them remain in operation. The list of strawboard manufacturers now defunct includes:
  

  • Agrifibre Industries Inc.
  • Alternative Construction Products Corp.
  • Basic Industry Technology Inc.
  • Isobord Enterprises Inc.
  • Naturall Fibre Boards LLC
  • Prairie Forest Products LLC
  • Pyramod International Inc.
  • Sea Star Trading Co.
  • Stramit USA LLC
  • Dow BioProducts Division of Dow Chemical Canada

  SierraPine, Ltd. of Roseville, Calif., (www.sierrapine.com) offers two formaldehyde-free MDF products:
  

  • Medex MDF for interior high-moisture applications
  • Medite II MDF for interior, non-structural applications

  Both are formaldehyde-free using an MDI (polyurea resin-matrix adhesive) as a binder rather than PF or UF. Another product: Medite FR2 (formerly Medite FR) qualifies as a Class 1 fire-retardant MDF panel but uses formaldehyde rather than MDI. SierraPine was using an MDI binder for Medite FR but switched back to formaldehyde due to the fact that the cost premium for MDI was causing them to lose significant market share. Also, MDI has experienced a greater demand than suppliers can typically meet causing serious shortages in recent years. Ultimately, the end-user's substitution of Medite FR for lower cost alternatives forced SierraPine to revert back to formaldehyde, renaming it Medite FR2 in the process. However, Medex and Medite II MDF continue to use MDI binders and all of SierraPine's MDF products are Scientific Certification Services certified for using 100 percent recovered and recycled wood fiber and achieve the same IEQ LEED credits as Resincore1 and PrimeBoard.

  Next time in part four, we'll conclude this series with a look at the new soy-based binders used as an alternative to PF for plywood and OSB sheathing.

  
  If you read this article, please circle number 344.

  
  
  

  Links

  • Rodman Ind.
  • PrimeBoard Inc.
  • SierraPine, Ltd.