Machine barrel for extruding UHMWPE (Ultra High Molecular Weight PolyEthylene)

Abstract

The invention discloses a machine barrel for extruding UHMWPE (Ultra High Molecular Weight PolyEthylene), and aims to solve the problems of high viscosity, poor fluidity, and susceptibility to fracture and degradation during the manufacturing process of the UHMWPE. The machine barrel of an extruder adopts a groove machine barrel; pins are arranged on the machine barrel; a copper sheathing is mounted around each pin. The extruder machine barrel provided by the invention can increase the friction between material and the machine barrel to guarantee strong forward transportation capacity, and is easy to plasticize and mix; the pins can be replaced conveniently; the copper sheathings outside the pins can achieve the functions of sealing, positioning and adjustment, so as to increase the extruding efficiency of the extruder and the mass of the UHMWPE.

Description

technical field [0001] The invention relates to a barrel for extruding ultra-high molecular weight polyethylene. Background technique [0002] Ultra-High Molecular Weight Polyethylene UHMWPE was first successfully developed in 1957 by the United Chemical Company of the United States with a Ziegler catalyst. This is a linear polymer with a molecular weight of 1 million to 5 million, a crystallinity of 65-85%, and a density of 0.92-0.96g / cm 3 Compared with many polymer materials, UHMWPE has the characteristics of small friction coefficient, low wear and excellent chemical resistance, and also has impact resistance, pressure resistance, frost resistance, heat preservation, self-lubrication, anti-caking Scale resistance, stress crack resistance, hygiene and other excellent properties. These excellent properties make UHMWPE pipes have important practical value. Known as "a rapidly rising new thermoplastic engineering material", it has important practical value in many fields. ...

AI Technical Summary

Problems solved by technology

Because UHMWPE has a large molecular weight, high viscosity, almost no fluidity, no viscous flow state, only rubber state, it is easy to cause the material to expand in the extruder when extruded by ordinary screw, and the back pressure is high, which cannot be achieved. Extrusion; in addition, the critical shear rate is extremely low, and melt fracture is prone to occur; due to the low coefficient of sliding friction, it is easy to slip when feeding; the heat release and heat storage in the extrusion process are difficult to control, resulting in the degradation of macromolecules, making the product The molecular weight of UHMWPE is less than one million, which leads to the weakening and disappearance of various excellent properties of UHMWPE, which seriously restricts the application of UHMWPE, and has become a hot topic jointly explored by the material science and industry circles since the 1980s.