Low temperature low-voltage extrusion method for ultra-high molecular weight polyethylene

Abstract

The invention discloses an ultrahigh molecular weight polyethylene low-temperature and low-pressure extruding method, which comprises the following steps: loading ultrahigh molecular weight polyethylene powder raw materials with the molecular weight more than or equal to 150 millions into an extruder, and pressing the raw materials for 3 to 5 minutes at a temperature of between 125 and 130 DEG C and a pressure of between 25 and 50MPa; melting the ultrahigh molecular weight polyethylene powder for 0.5 to 1.0 hour at a temperature of between 150 and 200 DEG C; cooling the molten fusant to the temperature of between 150 and 160 DEG C at a plunger speed of between 0.005 and 0.1 millimeter / second, and extruding the cooled molten fusant from an opening mold with the length-diameter ratio of between 2:1-4:1 so as to obtain an ultrahigh molecular weight polyethylene rod with a smooth surface and without distortion, wherein the extruding pressure is between 3 and 13MPa. The ultrahigh molecularweight polyethylene low-temperature and low-pressure extruding method utilizes common plunger extruding equipment to achieve continuous extrusion molding in one step without other changes, and low-temperature and lower-pressure processing reduces the energy utilization, and saves the cost.

Description

Technical field [0001] The invention relates to an extrusion method of ultra-high-molecular-weight polyethylene that uses ultra-high-molecular-weight polyethylene as a raw material to produce various rods, pipes and other plastic products. Background technique [0002] Ultra-high molecular weight polyethylene (UHMWPE) is a thermoplastic with extremely high molecular weight. The average molecular weight of UHMWPE defined by ISO 11542 and ASTM D4020 is greater than 1 million and 3.1 million, respectively. Compared with many polymer materials, UHMWPE has outstanding characteristics such as self-lubricating, low friction coefficient, low abrasion, impact resistance and stress cracking resistance, chemical corrosion resistance and biocompatibility. It is the material of choice for artificial joints. However, clinical follow-up found that the wear resistance of UHMWPE still cannot meet the requirements of long-term use. Improving its wear resistance is one of the key and difficult rese...

AI Technical Summary

Problems solved by technology

However, during the equilibrium process, hexagonal crystals only exist stably at high temperature and high pressure (>240°C, >360MPa), and it is difficult to meet such harsh conditions in actual processing.

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