WPC Decking

WPC decking, or composite decking, is a decking material solution made from a unique combination of wood fiber/wood flour and thermoplastic(s) such as polythene (PE), polypropylene (PP), polyvinyl chloride (PVC), or polylactic acid (PLA). WPC stands for Wood Plastic Composite and this composite is made up of 45% timber fibres and 55% HDPE and additives.

Excellent Durability

WPC decking is an ideal outdoor flooring solution because of its longer lifespan compared to a traditional timber deck. Due to the additional strength of the thermoplastic components, WPC decking is highly resistant to rot and decay and heat and wet weather conditions.

In addition to wood fiber and plastic, WPCs can also contain other ligno-cellulosic and/or inorganic filler materials. WPCs are a subset of a larger category of materials called natural fiber plastic composites (NFPCs), which may contain no cellulose-based fiber fillers such as pulp fibers, peanut hulls, coffee husk, bamboo, straw, digestate, etc.

Chemical additives provide for integration of polymer and wood flour (powder) while facilitating optimal processing conditions.

History

The company that invented and patented the process to create WPC was Covema of Milan in 1960, founded by Terragni brothers (Dino and Marco). Covema called WPC under the tradename Plastic-Wood. After a few years from the invention of the Plastic-Wood the company Icma San Giorgio patented the first process to add wood fiber/wood flour to the thermoplastics (WPCs)

Uses

Also sometimes known as composite timber, WPCs are still new materials relative to the long history of natural lumber as a building material. The most widespread use of WPCs in North America is in outdoor deck floors, but it is also used for railings, fences, landscaping timbers, cladding and siding, park benches, molding and trim, prefab houses under the trade name Woodpecker WPC. window and door frames, and indoor furniture. WPCs were first introduced into the decking market in the early 1990s. Manufacturers claim that WPC is more environmentally friendly and requires less maintenance than the alternatives of solid wood treated with preservatives or solid wood of rot-resistant species. These materials can be molded with or without simulated wood grain details.

Production

WPCs are produced by thoroughly mixing ground wood particles and heated thermoplastic resin. The most common method of production is to extrude the material into the desired shape, though injection molding is also used. WPCs may be produced from either virgin or recycled thermoplastics including high-density polyethylene (HDPE), low-density polyethylene (LDPE), polyvinyl chloride (PVC), polypropylene (PP), acrylonitrile butadiene styrene (ABS), polystyrene (PS), and polylactic acid (PLA). PE-based WPCs are by far the most common. Additives such as colorants, coupling agents, UV stabilizers, blowing agents, foaming agents, and lubricants help tailor the end product to the target area of application. Extruded WPCs are formed into both solid and hollow profiles. A large variety of injection molded parts are also produced, from automotive door panels to cell phone covers.

In some manufacturing facilities, the constituents are combined and processed in a pelletizing extruder, which produces pellets of the new material. The pellets are then re-melted and formed into the final shape. Other manufacturers complete the finished part in a single step of mixing and extrusion.

Due to the addition of organic material, WPCs are usually processed at far lower temperatures than traditional plastics during extrusion and injection molding. WPCs tend to process at temperatures of about 28 °C (50 °F) lower than the same, unfilled material, for instance. Most will begin to burn at temperatures around 204 °C (400 °F). Processing WPCs at excessively high temperatures increases the risk of shearing, or burning and discoloration resulting from pushing a material that is too hot through a gate which is too small, during injection molding. The ratio of wood to plastic in the composite will ultimately determine the melt flow index (MFI) of the WPC, with larger amounts of wood generally leading to a lower MFI.