In order to further improve the functions and characteristics of wood-plastic composite materials, wood composite materials are developing from a single structure to a multi-layer composite structure. This development trend is mainly due to the application of co-extrusion technology and full package technology in wood-plastic composite materials. Co-extrusion technology uses two or more extruders to melt the material and then extrude it continuously through a specific mold to form a multi-layer composite wood-plastic material.

The new generation of plastic-wood composite materials produced by co-extrusion technology has better material properties, longer service life, and is more economical and environmentally friendly. The advantages of co-extruded plastic-wood composites can be summarized as follows:

Resistant to moisture and immersion.

One of the advantages of wood-plastic composite materials is that it can absorb a certain amount of wood production waste, but wood fiber waste has high water absorption and is difficult to overcome, so that water-absorbing deformation, strength decline and freeze-thaw of wood-plastic composite materials can occur under certain use environments. problems such as cracking. The water absorption resistance of co-extruded plastic-wood composites is significantly better than that of non-co-extruded plastic-wood composites. The new generation of wood-plastic composite materials produced by co-extrusion technology will not be affected by the dimensional stability under the premise of increasing the ratio of wood powder/wood powder, and the expansion rate after water saturation is much lower than that of wood-plastic composite materials produced by non-co-extrusion technology.

The strength loss is small after immersion in water.

The strength loss of wood-plastic composite materials under adverse environments such as humidity and freeze-thaw cycles is one of the criteria for testing the material properties of wood-plastic composite materials. The strength loss of the new generation of wood-plastic composite materials produced by co-extrusion technology is less than that of wood-plastic composite materials produced by non-co-extrusion technology after soaking in water. This is because the degree of strength loss is determined by the thickness of the co-extrusion layer and the strength of the core material. The strength of the core material is low, but the strength loss is low when the thickness of the co-extrusion layer is large, which is more economically meaningful. Under the condition of the same co-extrusion layer thickness and core material strength, external fiber can enhance the physical and chemical strength of co-extruded plastic-wood composites.

Stronger anti-aging properties.

The new generation of wood-plastic composite materials produced by co-extrusion technology has far better anti-ultraviolet aging performance than wood-plastic composite materials produced by non-co-extrusion technology under the condition of adding light stabilizers in the production process. The multi-layer composite effect of the produced wood-plastic composite material largely delays the aging of the material under ultraviolet radiation.

Better flame retardant properties.

Wood-plastic composite materials produced by co-extrusion technology use flame retardants to make co-extruded layers, which optimizes the production method of adding flame retardants to wood fibers in wood-plastic composite materials of traditional non-co-extrusion technology, and the addition of flame retardants does not need to be considered The impact on the strength of the material greatly improves the flame retardant performance of the co-extruded wood-plastic composite material. The flame retardant performance depends on the thickness of the co-extruded layer. The concept of the flame retardant thickness is equal to the thickness of the co-extruded layer. The production of the flame retardant layer thickness can be controlled according to specific requirements, which reduces the production difficulty while improving the flame retardant performance.

Other News