Direct polymer extruder technology

Twin-screw extruder is a widely used continuous processing of polymer. Whether it can be extruded directly, that is, whether it can be completed at one time, can be divided into two categories: co-directional rotation and hetero-directional rotation. Coaxial twin screw into mixture and molding extrusion. Have strong ability of mixing, is mainly used for modification, filling, 1 directly enhance and plastic extrusion conditions and mixed with synthetic production of double screw alloys mixing operation, the extrusion system mostly adopts the modular direct extrusion condition is in the material is the premise of fully mixing structure, by varying synfuels fiasco tube component, the combination of the screw element to satisfy the extruder can build up enough pressure and flow stability. According to the specific mixing process of conveying, melting, mixing, descaling, homogenizing and so on, the situation of co-directional twin-screw extruder used in mixing is firstly analyzed.
1.Non – directional twin – screw can establish higher pressure and steady flow
Rotation speed and dispersion effect, mainly used for products requiring accurate section size molding and extrusion, such as cone-direction twin-screw screw higher relative speed can produce a high shape twin-screw extruder for PVC profile molding and extrusion. Compared with the shear rate and larger shear stress, the higher the rotation speed, the better the result. The single-screw extruder can adapt to a wider surface, but its various characteristics are not as good as the dispersive mixing effect. at the same time, the high rotation speed weakened the positive displacement of the twin screw so prominent, single screw is mostly used for molding extrusion, screw general role, so that the stability of the extrusion.
Special design according to specific extrusion process and product.
2.Principle of screw element design
In the use of special material production products need to mix granulation and molding extrusion mixing with the same direction of the screw element of the twin screw mostly according to “from clean” the original two steps, and mostly with the same direction of the twin screw and single screw to finish the design, this principle determines the longitudinal passage must be open, so that the two screw into. After granulation of double screw mixture, the material is cooled to room temperature, and material exchange occurs between single screw bars, as shown in figure 1 (a).When the longitudinal flow channel is open, the temperature rises again until the material melts. After two processing, it is possible to open the transverse flow channel to realize the increase of the consumption of adjacent screw slots of the same screw, the increase of processing cost, the prolongation of production cycle and the exchange of materials. As a result, the distributed mixing thermal history increases and the performance decreases. naturally leads to a problem: the ability, but also weakens the positive displacement effect