The influence of processing temperature on the properties of wood and plastic, wood-plastic composite material in the extrusion process is mainly affected by the barrel temperature and head temperature. The barrel temperature has a decisive influence on the mixing and plasticizing effect of the composites. The head temperature has an important effect on extrusion molding.
With the increase of the barrel temperature, the apparent viscosity of the composite system decreases. For the extrusion of the material, the elevated temperature contributes to the increase in fluidity. Group 1 experiments set the temperature of the extruder higher, but the temperature rise causes the wood fibers to burn, resulting in too low viscosity and insufficient Of the head pressure, the extruder's high temperature so that the material viscosity decreased, is not conducive to cooling stereotypes, easy to make products on the surface of the weld marks, the product surface roughness, poor strength, affecting the extrusion quality, and the extrudate in the cross-section Uneven heating process, the export mold due to the elastic recovery of the melt and the emergence of wave shape, affecting the appearance of the product quality.
Therefore, to meet the quality of materials on the basis of plastic, should try to reduce the extruder temperature.
The effect of temperature control on the quality of extruded products is very significant. If this temperature is too low, the viscosity of the wood-plastic composite material increases, the flow is difficult, the flow of the flow channel wall will be premature cooling and curing, so that the material can not be filled with the nose runner, difficult to extrusion; The surface temperature of the extruded article is greatly improved. Material through the transition section into the sizing section of the flow channel was molten state, in order to make the molecules are fully stereotypes, the head of the temperature should be sub-control, that is, the temperature gradually reduced. It can be seen that for the extrusion of wood-plastic composites, the head temperature is very critical, it directly affects the quality of extrusion molding.
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