Wood plastic composites have been booming in the USA since the 1990s. Composite materials made of wood fibers and thermoplastics which are used in numerous home-and-garden applications. They look like wood, can be processed like wood but offer significant advantages over the natural material. Above all, they are very resistant to weathering and can be used to manufacture products in an almost limitless range of shapes. Colortherm® inorganic pigments have proven effective for the coloring of these materials. These pigments can be used to very accurately recreate natural wood and earth tones, giving the products a deceptively realistic wood character.

Large quantities of high quality, cost-effective iron oxide pigments are now used in this application. Their easy processing is a particular advantage. These fine powder pigments distribute evenly into the mix and can withstand temperatures up to 260°C without changing color. These properties  make them particularly well suited to the extrusion process used to manufacture the composites. The UV and weather stability of the colorants also ensures that the products do not fade and retain high color intensity over a long service life.

The most significant advantage of wood plastic composites is the ease with which they can be formed. Whereas wood needs to be sawn, cut to size and coated, the extrusion of wood plastic composites produces a molded, finished, decorated piece in a single step, reducing effort and cost. The affordable and renewable wood content of 40 to 80 percent by weight in wood plastic composites is relatively high.

But the cost factor is not the only advantage of this flexible material. Its plastic component, generally polypropylene, imparts mechanical properties which are superior to those of natural wood. It is very dimensionally stable and flexurally stiff. The material is nearly impervious to moisture and therefore does not swell or warp. However, it can be sawn, sanded, planed or nailed like wood. Because the material is colored throughout, scratches which would immediately be noticed on a coated surface are barely noticeable.

Whether it is used for the supporting elements of a roof gable or a complicated conduit for antenna cable, the potential applications for the composite material are almost limitless. Exterior applications include fences, garden furniture, patio decking, window frames, roofing tiles and curtain walls. Interior applications include furniture, window sills, skirting boards and stairs. The material has also proven itself in shipbuilding applications because of its resistance to water.
The Global Competence Center Specialties will gladly answer individual customer inquiries with respect to this field of application or provide further information about LANXESS pigments.