Sustainable Development of WPC Products
The application of plastic wood products has been extremely hot in recent years. Together with steel, cement and plastic, ligneous materials are called the four basic raw materials. In the past 50 years, the main products of wood materials have gone through two generations. The first generation is wood sawing materials, and the second generation is artificial boards. The main components of wood are lignin, hemicellulose and cellulose. At present, most of the timber has been used by the man-made board and pulp industry, resulting in the reduction of forests, damaging the earth’s environment, and increasing calls to stop and reduce deforestation. On the one hand, people advocate replacing wood with steel and wood with plastic, but at the same time, they consume a lot of non-renewable oil and iron ore resources. This has or will lead to one raw material crisis after another. It also exacerbates the rise of CO2 in the earth’s atmosphere and the warming of the climate. On the other hand, there are not many big trees, people will use the method of compound many small materials will be used. A lot of glue must be used. More than 90% of them are urea-formaldehyde glue, which is the main source of formaldehyde pollution in the air. Now city dwellers are stuck in a third pollution period marked by “indoor air pollution”. Although people try their best to reduce the content of formaldehyde, the excessive reduction will inevitably affect the quality of wood-based panels. It can be seen that the second generation of wood materials do not technically upgrade and give up any formaldehyde-containing materials, indoor air pollution problem is not solved. It is under this background that plastic wood plate emerges at the historic moment. At home and abroad, the products with the rapid development of plastic wood are extrusion moulding, that is, the plate and strip with the narrow area. The equipment used is the double-screw extruder with taper degree, the same direction or different direction. 1. For the production of plastic wood materials and the shape of the plastic cover, it is necessary to use wood fibres that are screened and ground, and not plant fibres such as peanut shells and bean rods. Wood is a filler, so fundamentally, it is not wood but petroleum materials. 2. It is difficult to extrude and the scrap rate is high because it is an extrusion product with low density, low strength and poor rigidity. 3. Use plastic materials with large dosage, high cost and few varieties. 4. Equipment, moulds and auxiliary machines are expensive. 5. Due to the use of raw materials and timber, there is no energy-saving economic feature. Plastic wood products have advantages over traditional wood materials 1. Great contribution to environmental protection. All components of plant fibre are combined together without any pollution discharge. Materials that cannot be used are utilized and can be recycled 100% without secondary pollution. 2. It doesn’t need any glue. It’s really formaldehyde-free. 3. Products are widely used. In theory, most of the products made from plastics, wood, steel and cement can be replaced now. 4. Long service life, no water absorption, acid and alkali resistance, UV resistance, no decay, saving protection costs. 5. Save oil and ease the crisis. Make full use of the waste plastic to overcome the white pollution and find a good way to solve the white pollution. 6. Replace steel, aluminium, cement and plastics to reduce the consumption of mineral deposits. Steel, aluminium and cement are all produced from non-renewable raw materials on the earth. Sooner or later, they will encounter the problem of raw materials like oil. Scientific research shows that the energy consumption ratio of producing 1 ton of wood base material and 1 ton of cement, steel, plastic and aluminium is 1:4:60:45:130. This means that the product will save several times, dozens of times and hundreds of times more energy than other materials, and in turn will release several times, dozens of times and hundreds of times less CO2. Therefore, the sustainable development of green environmental materials – plastic wood, will be the new generation of green environmental materials.