同向双螺杆挤出机螺杆组合对EPS再生造粒的影响

Effects of Co-rotating Twin–Screw Extruder Combination on Recycling and Granulation of EPS

对同向双螺杆挤出机的螺杆组合进行了优化设计,并分析了螺杆组合对废旧发泡聚苯乙烯(EPS)再生造粒的生产工艺,以及EPS再生料的PS成分含量、分子量及其分布、玻璃化转变温度、流变性能的影响。结果表明,适当的螺杆组合是影响EPS再生造粒生产工艺稳定的关键因素;螺杆的脱挥和排气性能关系到残留发泡剂的去除,从而影响到EPS再生料的PS成分含量的高低;螺杆的剪切会降低EPS再生料的分子量并使分子量分布的范围变宽;螺杆的剪切也会降低EPS再生料的玻璃化转变温度;螺杆的脱挥和排气性能、剪切强度综合影响到EPS再生料的黏度。通过啮合块型号、数量及排列的优化来调整双螺杆的脱挥和排气性能、剪切强度和物料在螺杆中的停留时间,从而解决了EPS在再生造粒过程中残留发泡剂消除不充分、物料过度降解的问题。

The screw combination of co-rotating twin-screw extruder was optimized and the effects of the screw combination on granulation production process of recycled expanded polystyrene(EPS),and component content,molecular weight and distribution of EPS recycled materials,glass transition temperature,rheological property were analyzed.The results show that the proper screw combination is the key factor that affects the stability of the production process of recycled EPS granulation.The devolatilization and exhaust performance of the screw are related to the removal of residual blowing agent,which affects the content of EPS recycled materials.The shear of the screw reduces the molecular weight of the polystyrene material and widens the molecular weight distribution range;the shear of the screw also reduces the glass transition temperature of the polystyrene material;the devolatilization and exhaust performance of the screw,shear strength comprehensively affect the viscosity and shear sensitivity of polystyrene materials.The optimization of the type,quantity and arrangement of the meshing block is used to adjust the devolatilization and exhaust performance,shear strength and the residence time of the material in the screw.Therefore,the problems of insufficient elimination of residual foaming agent and excessive degradation of materials during the regeneration and granulation process of waste EPS are solved.