Production
The materials in this group consist essentially of wood or of the wood constituent lignin as well as binders, including corn, natural and synthetic resins. The content of renewable raw materials may fluctuate between 50 and 100% depending on the type of material.
Wood is used in the form of spruce, in the form of shavings or sawdust. Wood scrap that satisfies the property requirements is also suitable and is both ecologically advisable and economically favorable. About 60 million tons of lignin accumulates every year as a byproduct of paper production, a small part of which is utilized as material.
Fabrication and properties
Depending on the composition of the compounds, the strength, stiffness, thermal shape stability and other material properties may be adjusted within certain ranges. The material also displays properties similar to those of wood in terms of swelling and shrinkage.
These materials can be fabricated on conventional plastic-working machines without special additional equipment. The surface is not shiny as in the case of conventional plastics and nontransparent because of the fillers. Like wood, these materials can be enameled, glazed, sprayed and also powder coated. In addition, by mixing in master batches, the finished parts can be imbued with color.
Due to the high density and wall thickness the parts have excellent acoustic properties, for which reason they have been proven especially useful in the construction of musical instruments and speaker housings.
The prices for this material group range between €1.50 and €10 per kg.