Introduction of raw materials for wood-plastic composites (1)
There are four main raw materials for making wood-plastic composite materials: thermoplastics; wood fibers or wood flour; coupling agents; additives. The wood component is the most common plant-based filler, but other agricultural plant fibers are also used in large quantities. Coupling agents are also sometimes classified as additives. Although they are used in a small amount in WPC composition, they are indeed indispensable and important components, which have a significant impact on the processing process and performance of finished products. If the fiber content is high, sometimes it is necessary to add a small amount of thermosetting value. For example, adding phenolic resin can improve the interface bonding strength and improve the material properties.
Plastic Raw Materials
Limited by the stability of wood, WPC production can only use plastics that can be processed with melting points below 200 ° C. Commonly used plastics in production are native and recycled polyethylene (PE), polypropylene (PP), and polyvinyl chloride (PVC). ). PE has always been the most important plastic raw material, but in the future, the demand for PVC will gradually increase.
Polyethylene is a polymer obtained by the direct polymerization of ethylene. It is the plastic with the simplest chemical composition and molecular structure, the largest production volume, and the widest application. Polyethylene is a typical soft and tough polymer. It has good toughness and good low-temperature resistance in general environments.
Polyethylene itself is non-polar and has excellent electrical insulation. And because its water absorption is very small, less than 0.01%, its electrical properties are basically not affected by changes in environmental humidity.