1. Wood selection
Wood plastic composite decking
board wood raw materials can be sawdust, wood powder, wood fiber. Wood powder is made by drying and grinding sawdust, divided into different grades according to the size of the particle, from coarse to ultra fine, moisture content is lower than. Wood fibers can be made from recycled wood pulp fibers. Waste wood can also be used as raw materials for wood-plastic panels. Waste wood mainly includes the wood waste produced by the secondary processing of the post-industrial wood waste of the material processing plant. In the selection of scrap wood as raw materials for production, must develop a specification standard, according to the standard and specification parameters to select raw materials. In some developed countries, consumer waste wood has been excluded as a source of raw materials for wood plastic composite decking
board production, mainly relying on the above materials. As raw materials for production, the cleanliness of waste wood is very important. Small amounts of glue, paint and veneer materials, if not more than, generally belong to the acceptable range. The Washington cleaning center in the United States has developed standards for the degree of corrosion, metal and plastic content, and dirt content of scrap wood.
2. Plastic part selection
The choice of plastics the choice and treatment of plastics depends on several factors, and when wood degrades at high temperatures, the plastic can still be treated and used at ℃. The polymers used in WPC are mainly polyethylene, polypropylene and polystyrene. Any plastic that can be melted and processed below the degradation point of the wood is suitable for the production of wood plastic composite decking
panels. For further performance improvement and cost control reasons, recyclable resins and raw materials will also be used. According to the current production technology of WPC, different applications of WPC determine the choice of different plastics. For example, the WPC for outdoor use mainly chooses polyethylene as the raw material.
: high-density polyethylene. It is usually used to make milk bottles. This translucent material is more valuable on the market.
: low-density polyethylene. It is used for a wide range of purposes, usually as a packaging film. A foreign company every year with a low-density polyethylene waste film production wooden plastic board trestle.
: polyvinyl chloride. Consumption of polyvinyl chloride is usually used as a daily packaging material and edible oil packaging, due to the small amount, can not be used in the production of the wood plastic composite decking board.
: polypropylene. One of the most widely used general purpose plastics for life and industry, it is widely used in automotive interiors and furniture. Although polypropylene is the main raw material of WPC, it is much larger than recycled polypropylene. Plastic processing technology determines that small and uniform particles for material feeding, bending and deep processing will be more beneficial. At present, the recycling methods of polymer plastics mainly rely on machinery. Waste plastic is decomposed into small particles and pellets, which can be reused in the production of new products. It is very important to clean the recycled plastic. For some waste plastics with high recycling costs, which are not suitable for further processing, they tend to be buried.
3. Application of additives
As a necessary element in the production of WPC, additives have different effects on the quality and application of WPC. These additives include adhesives, stabilizers, pigments, lubricants, fungal repellents, and foaming agents. The table below lists the applications of different additives in the manufacturing process.
The organic combination of wood powder and plastic makes the material hard, but much more brittle than unmixed plastic. Because of the use of foaming agent and other reasons, wood plastic composite decking
board and the same specification of wood products compared to the low strength, hardness and bending strength is also low. However, the low water absorption of WPC offsets these deficiencies and makes WPC more corrosion resistant. The ability to absorb ultraviolet rays further reduces the damage suffered by the plate under the sun exposure.