1.1 Denfinition of wood plastic composite materials
Wood plastic composite （WPC) is a booming new type of composite materials at home and abroad in recent years, which refers to the use of polyethylene, polypropylene and polyvinyl chloride instead of usal resin adhesive, mixed with more than 50% of the rice husk and wood powder, straw and other waste plant fiber to shape new wood materials by extrusion extrusion, molding, injection molding and other palstic processing to produce plates or sections. These products are mainly used for building materials, furniture, logistics, packaging and other fields. The plastic and wood plastic composite are mixed ata certain ratio then extrude to the plate, which is called extrusion wood plastic composite board.
1.2 The mian characteristics
The basis of wood plastic composite materials are high-demsity polyethylene and wood fiber, which determines their own charcteristics
1) Excellent process ability
Wood plastic composite material contains palstic and fiber, therefore, it has the processing performance that is similar to timber so it can be sawed, nailed, planed by using carpentry tools, meanwhile, the ability of nail holding of WPC products is much better than that of wood materils. The ability of nail holding of WPC products is 3 times than that of wood, 5 times than that of particleboard.
2) Excellent property of strength
Wood plastic composite material possesses better elastic modulus because of containing plastic. In addition, because the embedded fibers and palstics are fully mixed, it has physically mechanical properties of compression, bending which are similar to hardwood, and its durability is much better than that of ordinary wood materials. The hardness of surface treatment is 2-5 times than that of general wood.
3) Anti-water, anti-corrosion with long service life
Compared with wood, wood plastic composite material and its products can be strong acid and alkali resistance, anti-water, anti-corrosion, anti-bacteria, anti-moth and anti-fungus with long service life of over 50 years.
4) Excellent adjustable performance
Polynaerization, foaming, curing, modifications and other changes happen to the palstic by using addtives, which not only changes the density and strength of wood plastic materials, but also achieves some special requirements, for example, anti-aging, anti-static, flame retardation.
5) It has a good qualities of UV light stability and painting.
6) Its biggest advantages is to turn waste into treasure, and can be rcycled 100% repeoduction. It can be decomposed, which does not cause "white pollution". Thus wood plastic composite material is the real green environmental protection products.
7) Extensive sources of raw materials
The main raw material of WPC is high density polyethylene or polypropylene, and wood fiber can be wood flour, bran or wooden fiber, in addition, a small amount of additives is necessary.
8) It can be made to any shape and size according to the requirement.