Effect Of Control Temperature Of Extruder And Improved Screw On Chain Extention Of Bottle Flakes

There are some deviations for the E thermocouple temperature measurement and the actual temperature of the plastic extruder, it can not be corrected completely within intelligent instrument. The PT100 Film Platinum Resistance which was produced by the development of new technology can be installed and controlled precisely in temperature-control-instrument of extruder. There is a huge influence in temperature distribution of the barrel when open-direction of heating-ring is changed. It is the most homogeneous temperature distribution of all and top temperature is almost same as the bottom temperature in barrel of extruder when open-direction of heating-ring is up.By improving on tail design of the extrusion screw,increasing three feed thread,and screw barrel which is composed of two exhaust ports are merged into a vent, installing heating coil with an upward opening, improving new type temperature measurement element etc.It shows that the reaction extrusion chain of PET tablets is favorable after debugging.The effect of sampling time, extruding temperature, screw speed, vacuum degree, amount of chain extender, water content of PET bottle flakes on the intrinsic viscosity ([η]) of extrudate was studied with improved reactive extruder.The experiment found that the screw speed in the range of 40-80r/min,the samplings after 5 minutes’extrusion which can represent the practical [η]. The [η] of the extrudate will increase when PET bottle flakes were extruded in high screw speed, low barrel temperature of extruder and high vacuum degree after drying. The [η] of product could arrive 0.76 dL/g with optimum processing condition, the condition is:barrel temperature 230,250,250,250,240℃, vacuum degree 0.08MPa, screw speed 80 r/min.The [η] of product increased when PMDA was added into PET bottle flakes, the viscosity increased significantly, reaching 0.82dL/g, and the melt strength of products improved significantly;the more moisture,the lower [η]of extrusion products.Water content does not affect [η] of product and extruding process when it is less than 2% with this reactive extruder.Based on modern instrument analysis showed that molecular structure, crystal type, melting temperature of extrusion products is exactly the same with industrial production of PET material, the purity and intrinsic viscosity of products can meet the needs of PET products.