Technology And Screw Optimization Of Reclaimed Rubber Producted By Screw Extrusion

The method of the screw continuous extrusion method has become a mainstream devulcanizing method due to high automation degree,environmental protection,and good performance of reclaimed rubber.The single-screw extrusion method is to provide temperature and pressure to the rubber during the extrusion process,as well as to ensure the residence time of the material,so it can achieve the devulcanization of the material and achieve continuous extrusion.Domestic and foreign scholars have done a lot of research on the method of preparing reclaimed rubber using screw extrusion method.The optimization of process parameters and screw are the necessary ways to improve the quality and yield of reclaimed rubber.In this paper,the powder of waste tire rubber was devulcanized by using flat vulcanizing machine.The effect of different process parameters on devulcanization performance was studied.The Mooney viscosity and mechanical properties were used as evaluation indexes.The results showed that the devulcanization temperature was 250℃ and the regeneration time was 10 minute.and pressure of 2.5 MPa can obtain a good effect.The devulcanization section adopts the combined screw structure of common screw,main and auxiliary screw and pin screw.Based on the software of Polyflow,we analyzed the influence of screw structure and rotation speed on the average residence time and screw conveying capacity.The speed was determined to be 20r/min to ensure residence time and production.The screw structure was determined to ensure residence time and production From the perspective of ensuring the pressure of the rubber in the devulcanization section,the amount of material supply and pressure supply upstream of the desulfurization section and the required downstream back pressure are determined.Based on the structure and process of the obtained devulcanization section,the configuration of the upstream and downstream functional sections of the desulfurization section was studied.According to the theory of Darnell-Mol,the structure of the feed section is determined from the perspective of ensuring the solids transport rate of the feed section.The compression section is determined from the perspective of ensuring the supply of material and pressure to the desulfurization section.The structure of the shunt ring was determined from the viewpoint of ensuring that the pressure of the devulcanization section and the pressure of the downstream exhaust section were low.The second compression section and the extrusion section structure are determined from the viewpoint of ensuring that the resistance of the head can be overcome and the balance of the upstream and downstream flow of the exhaust section.