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Doug Smock

Sawdust Shortage May Crimp Injection Molding Growth

One of the weirder materials developments from the economic slowdown is a shortage of sawdust. Prices are up some 25 percent in the past two years, if you can get it. Sawdust is not normally considered an engineering material, but it’s often used as an additive for plastic compounds that cover steering wheels and dashboards. Demand for wood plastic composites has grown dramatically and is close to a billion pounds this year, mostly for construction applications. Composites are typically close to half wood flour and high-density polyethylene, with a smattering of other additives such as stabilizers and pigments. Wood plastic composites are favored for automotive applications because they have a lower specific gravity than compounds made with other inorganic materials. They also give an “organic” look and are considered environmentally friendly. The new economics, however, surely will slow penetration. The reason is the slowdown in house construction, which is slowing timber operations. The weakness of the US dollar versus the Canadian dollar also is having an impact.