Preparation method and device of high performance polymers pipes

Abstract

The invention discloses a method for preparing a high-performance polymer pipe. The method adopts the steps that during the extrusion molding process of the pipe, the crystallization, the orientation or the dispersed phase morphological structure of the polymer pipe can be adjusted, controlled and fixed through the shearing action generated by the rotation of a core rod in a machine head relative to an orifice die, or the rotation of the orifice die in the machine head relative to the core rod, or the rotation of the core rod and the orifice die in the identical or opposite direction simultaneously, and by cooling and shaping the inner wall and the outer wall of the extruded pipe simultaneously, and adjusting and controlling the temperature field, the cooling rate and the temperature gradient during the extrusion molding process of the pipe. The invention further discloses a device designed according to the method. The method has the advantages that the macromolecular orientation, the crystallization or the dispersed phase morphological structure which are generated through induction can be retained in the plastic pipe, so that deorientation can be avoided, the internal stress of the pipe can be reduced, and the performance of the pipe is improved.

Description

technical field [0001] The invention belongs to the technical field of polymer pipe processing methods and equipment, and in particular relates to a preparation method of high-performance polymer pipes and a processing device for realizing the method. Background technique [0002] Conventional plastic extruded pipes have the following problems in the process of processing: (1) The melt flow through the shunt shuttle will produce weld marks, which will reduce the hoop strength of the pipe; (2) Due to the axial (extrusion direction) tension during processing stretching, the polymer macromolecules are oriented along the axial direction, and the crystallization is orderly, so that the axial strength of the pipe exceeds the hoop strength, but in actual use, the hoop force of the pipe is more than 2 times that of the axial direction, which cannot meet the use requirements; (3 ) is cooled by spraying on the outer wall, which makes the inner and outer walls of the pipe uneven in tem...

AI Technical Summary

Problems solved by technology

[0002] Conventional plastic extruded pipes have the following problems in the process of processing: (1) The melt flow through the shunt shuttle will produce weld marks, which will reduce the hoop strength of the pipe; (2) Due to the axial (extrusion direction) tension during processing stretching, the polymer macromolecules are oriented along the axial direction, and the crystallization is orderly, so that the axial strength of the pipe exceeds the hoop strength, but in actual use, the hoop force of the pipe is more than 2 times that of the axial direction, which cannot meet the use requirements; (3 ) is cooled by spraying on the outer wall, which makes the inner and outer walls of the pipe uneven in temperature and temperature, and the crystallization degree of the material is different. There are internal stress defects, resulting in low mechanical properties of the pipe, which greatly limits the application as a plastic pressure pipe.

However, there are still some problems in the above technology: (1) because the mandrel sleeve that realizes the rotating force field does not extend to the outlet end of the die, when the die section still has a relatively high temperature, when the polymer melt leaves the mandrel When the sleeve is no longer subjected to the action of the rotating shear force field, it will undoubtedly make the oriented material easy to relax, so it is difficult to control the crystallization of the tube or the shape and structure of the dispersed phase; (2) because it is not considered in the design The inner wall of the extruded pipe is cooled, and the crystallization or dispersed phase morphology or structure of the pipe cannot be adjusted and controlled by adjusting the temperature field and temperature gradient

(3) Due to the action of rotating shear, the diameter of the pipe extruded from the die will shrink greatly. On the one hand, it will affect the smooth entry of the pipe into the cooling and shaping mechanism, and on the other hand, it will also affect the diameter of the extruded pipe. accuracy

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