Wood-plastic composite substituting for traditional wood product
Wood-plastic composites are substituting for traditional wood products
Technologies for wood modiﬁ cation and wood-plastic production have been known for a long time, but market interest grew only when consumers became concerned about wood preservatives and illegal logging of tropical wood species. Additionally, reduced availability of many tropical species and higher tropical timber prices have made wood modiﬁ cation techniques ﬁ nancially viable.
Wood is modiﬁ ed either through heat treatment (thermal modiﬁ cation) or chemical treatment such as acetylation. All modiﬁ cation techniques change important wood properties, such as moisture absorption, dimensional stability, biological durability, hardness and colour, and they aim at improving typical disadvantages of wood.
The volume of chemically modiﬁ ed wood products on the market is very small, while thermally modiﬁ ed wood products and wood-plastic composites are now widely available. The goal of this section is to describe these products, their markets and applications in Europe, and resulting opportunities for Canadian manufacturers.
Wood-plastic composites (WPC) are a form-shaped composite material made of cellulosic particles, such as wood ﬂ our, and thermoplastic polymers. The wood mass share of the ﬁ nished product usually lies between 25% and 85%. At present wood is used as a ﬁ ller material, but research is under way to use wood ﬁ bre to improve WPC’s mechanical strength properties.
Advantages of WPC include the possibility of producing many different shapes without any waste, and the option of veneering. WPC has better dimensional stability, weather resistance, low maintenance cost and extended lifetime compared with many wood products. Mechanical performance is relatively poor however, limiting WPC’s present use to non-structural end-uses.
The most common end-uses are currently in non-load bearing construction such as outdoor decking and siding. Outdoor products (siding, decking, fencing,etc.), furniture, construction, automobile parts and infrastructure applications are regarded as the most promising growth markets for WPC in Europe. The estimated market share of WPC in total wood product consumption in Europe was estimated at far less than 1% in 2006, but annual growth rates in WPC consumption are estimated at over 10%. European WPC production was estimated at approximately 100,000 tons in 2007 The leading countries are Germany, Austria, Belgium, Netherlands and Scandinavia.
Differences exist between North America’s more mature WPC market and Europe’s smaller, but fast growing market. While decking accounts for over half of WPC volumes consumed in North America, WPC end-uses in Europe are more varied and there is no single dominating end-use application for WPC. In 2007, a quality assurance label for WPC decking was introduced in Europe, to establish standardized performance values. Eight companies from Belgium, Germany and the Netherlands have applied to have their WPC products certi- ﬁ ed under the new quality label.
While outdoor products, and furniture in particular, are expected growth markets for WPC in Europe, consumer surveys found considerable caution towards WPC as a new material. In Austria and Germany, consumers surveyed preferred wood materials to WPC in decking, even when considering maintenance and product lifetime.