Utilization of Bark

Approximately 200 tons of Douglas-fir bark each day reach the Weyerhaeuser Timber Company plant in Longview, Washington. Progress is being made in finding uses for this material. Fir bark consists of layers of cork, short spindle-shaped fibers, and a fine, amorphous powder. Because of their different physical properties, these can be separated by mechanical methods into pure cork, pure fiber, and powder, or into blends of these materials. Products have been manufactured from these materials under the commercial name Silvacon. The uses of the product are diverse. Silvacon 472 is an extender for adhesives used in the Douglas-fir plywood industry. The plastic qualities of Silvacon formulations also make it suitable for use in phenolic plastic molding compounds; the manufacturer can conserve on resin usage and improve impact strength. Silvacon 412-filled oxychloride cement is used in industrial and office building flooring, and a special formulation of this material known as Plastinail flooring is being used to renovate boxcars. Silvacon 412 and Silvacon 490 are used as conditioners for fertilizers and insecticides. Silvacon 490 is also used as a dispersing agent in rubber production, and Silvacon 412 is also used as a filler and stabilizer in asphalt roof coating. Products commercially known as Silva-flake, Silvacel, and Superbridge have been adapted for uses in the oil drilling industry. Problems facing the development of bark products include the cost of transportation from the west coast to the eastern industrial markets, and the competition from other materials.

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