Core Technology Analysis of PVC Based WPC Granulating Line

PVC wood-plastic composite materials cleverly combine polyvinyl chloride (PVC) with wood powder or other plant fibers. This fusion is achieved through a specific process to complement the advantages of the two, thus forming a composite material with excellent performance. The extensive use of waste plastics and plant fibers in its production process greatly reduces the demand for new resources and reduces the pollution of waste to the environment; compared with traditional wood materials, it has achieved superiority in many performances, providing better quality and more environmentally friendly material options for various industries. ​

Core components of the production line​
In the PVC based WPC granulating line, the screw and barrel of the conical twin-screw extruder are uniquely designed, and the special configuration is used to optimize the mixing, dispersion and plasticization process of the material. The special thread shape and rotation mode of the screw can exert precise and efficient shear and extrusion forces on it during the material conveying process, so as to fully mix the PVC resin with fillers such as wood powder and ensure that each particle can be evenly distributed. ​The material selection and treatment process of the screw barrel are also crucial. In order to deal with the wear and corrosion problems that may occur during the processing of materials such as wood powder, the barrel is treated with bimetallic treatment. This treatment method gives the barrel extremely high wear and corrosion resistance. From a long-term operation perspective, it not only reduces the downtime and cost caused by frequent equipment replacement, but also reduces the complexity and frequency of maintenance work, significantly improving production efficiency and economic benefits. The granulation auxiliary machine works together with the conical twin-screw extruder to complete the transformation from mixed materials to high-quality plastic particles. The die face pelletizing device quickly and accurately cuts the extruded strip-shaped materials into particles of uniform size by accurately controlling the contact timing and strength between the tool and the extruded material. The air conveying and aggregation system uses wind power to quickly and smoothly transport the cut particles to the designated location to avoid damage to the particles due to collision and friction during transportation, ensuring the integrity and surface quality of the particles. The vibration separation and cooling equipment further removes impurities and unqualified products from the particles through vibration screening, and uses cooling media such as air or water to quickly reduce the temperature of the particles to achieve suitable storage and subsequent processing conditions.​

Properties of the produced plastic granules​
PVC resin itself has a certain rigidity and toughness. After being fully mixed with wood powder or other fiber fillers, it forms a structure similar to "reinforced concrete". This high-strength characteristic enables building materials, furniture parts, etc. produced with this as raw material to withstand greater external forces, not easily deformed or damaged, and extend the service life of the product. ​PVC material itself has excellent chemical stability and can resist the erosion of various chemical substances. In PVC wood-plastic composite materials, this characteristic is further enhanced. After being mixed with PVC resin, fillers such as wood powder are tightly wrapped inside the resin matrix to avoid direct contact with external corrosive media. In a humid environment, the erosion of chemical substances such as acids and alkalis, products made of plastic granules produced by PVC based WPC granulating line can maintain good performance and will not have problems such as corrosion and rust. This characteristic makes it have a wide range of application prospects in the fields of building exterior wall decoration, chemical equipment protection, outdoor facilities, etc. ​Over time, the products produced by PVC based WPC granulating line have excellent anti-aging performance. The molecular structure of PVC resin is relatively stable, and it has a certain absorption and shielding effect on ultraviolet rays. The anti-aging additives added during the production process can further inhibit the aging reactions such as molecular chain breakage and oxidation of the material during long-term use. Even if exposed to harsh outdoor environments for a long time, the color, gloss, strength and other properties of the product can still remain relatively stable, and it is not easy to fade, powder, crack and other aging phenomena. ​

Process optimization and quality improvement​
In the production process, the mixing, dispersion and plasticization of materials are directly related to the quality of the final product. The production line achieves the best processing state of the material in the extruder by accurately controlling key parameters such as screw speed, temperature distribution, and material conveying speed. In the mixing stage, the special design and speed control of the screw enable PVC resin and fillers such as wood powder to reach a highly uniform dispersion state in a short time; in the plasticization stage, the temperature and pressure are precisely controlled to ensure that the material can be fully melted and plasticized to form a melt with uniform texture and stable performance. ​In response to the problem of residual moisture and volatiles in wood powder, the production line takes a series of effective measures. In the raw material pretreatment stage, the wood powder is strictly dried to reduce its moisture content; an exhaust device is installed at the appropriate position of the extruder to discharge volatiles in time during the plasticization process of the material. These measures effectively avoid quality problems such as internal bubbles and surface defects of the product caused by residual moisture and volatiles, and improve the appearance quality and internal performance of the final product.