Wood plastic composite (WPC) is panel or lumber product made from recycled plastic and small wood particles or fibers. Wood plastic composites are relatively new products as compared to the long history of natural lumber or traditional wood composites such as particleboard or fiberboard.
This fact sheet summarizes some of the basic manufacturing steps, physical and mechanical properties, as well as major uses of WPC.
Wood plastic composites are widely used in the U.S. They are manufactured by mixing wood particles as fine as flour and recycled plastics. North American WPC market have reached almost $1 billion in sales.This is an increase of 200% between 2001 and 2006, and it is expected that 20% annual growth will take place within the next 5 to 6 years. As WPC capacity increases, new products are being developed such as door stiles, rails and window lineal.
The greatest advantage of WPC is its environmentally friendly approach of using waste wood and recycled plastic material. Wood composite plastics have low maintenance cost as compared to that of solid wood. One of the main reasons responsible for the fast growth of WPC is its low-life cycle cost.
In general, WPC deck has a production cost of about 15% more as compared to that of pressure-treated lumber, but requires a lower maintenance cost. The actual payback period is estimated at 3 to 5 years compared to pressure-treated decking material. Its excellent dimensional stability along with less variability also can be considered as another main advantage of WPC products.
Most of the research in many countries is concentrating on the durability and extended service life of WPC due to large interest in its outdoor use.
In fact, WPC was originally marketed as being naturally decay resistance against fungi or insect attack. However, it has been shown that WPC will still absorb some moisture and eventually decay but at much slower rate than solid wood.
Thermal expansion, creep (time dependent deformation), high density and difficult application of paint would be some of the other disadvantages of WPC.