Wood-plastic Composite Co-extrusion Molding Technology
Co-extrusion technology is one of the popular polymer molding technologies today. This technology can concentrate the excellent properties of different materials into the same product.The complementary properties of each material greatly expand the application scope of polymer materials.It is widely used in plastic profile co-extrusion, flat film and cast film co-extrusion, composite film co-extrusion, composite pipe co-extrusion, and coating co-extrusion of wires and cables.
Wood-plastic composite material combines the ecological characteristics of wood and the processability of plastic materials. It is a new type of composite material that is low-cost, green and environmentally friendly.The effect of different wood fiber contents on the creep resistance of wood-plastic composites was studied.The results show that increasing the content of wood fiber cannot fundamentally change the creep defects of wood-plastic composites due to the viscoelastic properties of linear structural thermoplastics.Excessive wood fiber content can even lead to new problems such as brittle fracture and decay of the material. As a building material, wood-plastic composite materials have certain requirements for their flame retardancy. In order to solve the problem of poor flame retardancy of traditional wood-plastic composite materials, basalt and talcum powder components are added to the shell structure of wood-plastic composite materials. It improves the flame retardancy of wood-plastic composite materials without reducing or even slightly improving the physical properties of wood-plastic composite materials.
As one of the important molding methods in the field of polymer processing today, extrusion molding technology has the characteristics of high production efficiency and wide adaptability. Since its inception, it has attracted widespread attention from domestic and foreign scholars. The future development trends of extrusion molding technology are as follows.
1) At present, relevant research on reaction extrusion molding technology, co-extrusion molding technology and gas-assisted extrusion molding technology is mostly concentrated in the field of process parameters or materials. In the future, relevant mechanisms should be studied in depth and universal mathematical or physical models should be established. .
2) At present, the extrusion molding equipment used in industrial production does not monitor the temperature field or pressure field inside the barrel accurately enough.More reasonable extrusion equipment should be developed to achieve extrusion molding with wider uses, higher precision, and better quality.
3) Numerical simulation can significantly save time and money in the extrusion product development or mold design process, but existing numerical simulation software has certain limitations.Numerical analysis software with wider applicability and more accurate simulation results should be developed to achieve the purpose of using simulation results to guide actual production.
4) Extrusion molded products are developing in the direction of miniaturization and precision, and the microstructure determines the macroscopic performance.It is necessary to conduct in-depth research on the microstructure, mechanical properties, optical properties, etc. of extrusion molded products from the micro level, explore the impact of methods, processes, equipment, raw materials, etc. on the micro level of products, and analyze their impact mechanisms.Fundamentally solve the existing key problems of extrusion molding technology.
