How is Wood Plastic Composite Decking Processed
The wood plastic composite materials contain plastic, so it has good elastic modulus. In addition, due to the inclusion of fiber and fully mixed with plastic, so with the hardwood equivalent of the compression, bending resistance and other physical and mechanical properties, and its durability is obviously better than ordinary wood materials. Surface hardness is high, it is lumber commonly 2-5 times.
Artificial zeolites, the aluminosilicate molecules that capture the powder and absorb odors in the material, can be added to the polymer. The adsorbent traps small organic molecules that produce odors through a large number of crystalline cavities in the powder. Molecular capture adsorbents have been successfully used in polyolefin extruding tubes, injection and extrusion blow molding vessels, isolation packaging materials, extruding packaging and sealing materials. Molecular adsorbed powders can also be used as dehumidifiers to remove moisture from plastics.
The Baking Temperature of Wood Plastic Composite Materials
Wood plastic composites materials are mainly affected by barrel temperature and head temperature during the extrusion process. The temperature of cylinder has a decisive influence on the mixing and plasticizing effect of composite materials. The head temperature has an important influence on extrusion molding.
With the increase of barrel temperature, the melt of the composite system showed that the viscosity decreased. For extrusion processing of materials, rising temperature is helpful to increase the fluidity.
General extruder temperature set too high, will lead to wood fiber charring, resulting in too low viscosity and can not produce enough head pressure, and is not conducive to the cooling and shaping, easy to make the surface of the products appear weld marks. The surface of the products is rough, the strength is poor, and the extrusion quality is affected, and the extrusion process is uneven on the cross-section. After the exit of the die, waves appear due to the elastic recovery of melt, which affects the appearance quality of the products. Therefore, on the basis of meeting the plasticizing quality of materials, the extruder temperature should be reduced as far as possible.
The influence of temperature control on the quality of extruded products is very significant. If the temperature in this section is too low, the viscosity of the wood plastic composite materials will increase and the flow is difficult. The material flow on the wall of the flow channel will be cooled and solidified too early, so that the material cannot fill the flow channel of the nose and it is difficult to extrude and shape. If the temperature of this section is increased, the surface quality of extruded products has been greatly improved.
The material is in a molten state when flowing through the itd into the channel of the shaping section. In order to make the molecule fully shaping, the temperature of the head should be controlled in sections, that is, the temperature gradually decreases. It can be seen that for the extrusion molding of wood plastic composite material, the temperature of the head is very critical, which directly affects the quality of extrusion molding.
Extrusion products of different sizes and shapes increase the diversity of wood plastic composite decking
When profiles are not required to have a continuous sheet structure or components with a complex structural design, WPC profiles can be injection molded or molded. Processors sometimes face the problem of how to fully mold wood plastic composite materials during processing. To solve this problem, they need to reduce the amount of wood filler to increase the fluidity of the melt.
Since 200° C is the upper limit for the operating temperature of wood-plastic composites, some resins, such as PET, whose melting point exceeds 200° C cannot be used in the wood plastic composite decking.
Moisture degrades the properties of the composite and also helps to breed microorganisms, so be sure to remove moisture before using wood fillers. Before the processing of wood packing to dry treatment, generally required to deal with the moisture content of less than 1~ 2%.
Current wood plastic composite materials processing machinery requires feeding equipment, drying equipment, extrusion equipment and molding equipment, as well as some necessary downstream equipment such as cooling water tanks, traction equipment and cutting equipment.
Wood Plastic Composite Decking Processing
Suitable additives are needed to modify the surface of polymer and wood powder to improve the interface affinity between wood powder and resin.
The dispersion effect of wood powder with high filling amount in the molten thermoplastic is poor, making the melt fluidity poor and extrusion molding difficult.
The plastic substrate also needs to add various additives to improve its processing performance and the service performance of its products.