Optimization Of Process And Cooling Equipment For Polypropylene Sheet Extrusion

Polymer foam is used in modern industry and life widely.Foam has great advantages in terms of shock absorption,transportation,packaging,noise reduction and filtration due to its unique porous structure.Polypropylene,a thermoplastic material,due to its superiority has made rapid development in recent years.Polypropylene as a thermoplastic semi-crystalline polymer has many advantages,relative to polyethylene and polystyrene.Its crystal temperature and melting temperature is much higher than the glass transition temperature.It can still maintain most of the mechanical properties at high temperature.Polypropylene also has obvious advantages as foamed material and has advantages in terms of-usability,production cost and environmental friendliness.Its products have many advantages,such as good thermal stability,excellent seismic energy absorption and high recovery rate after deformation,strong chemical resistance,oil resistance,high tensile strength,impact strength and toughness and so on.The paper mainly studies on polypropylene extrusion foaming processing technology,and extrusion foaming is a cointinuous production processing technology.Several parameters in the production process affect the final product quality together,such as raw material performance,equipment capacity,processing parameters and so on.In this paper,from a number of perspectives,the impact of various aspects of polypropylene extrusion foaming characteristics and degree of impact,to explore the impact mechanism in the foaming process.Blending modification has been a simple and effective method of improving material properties.In this paper,the rheological properties and foaming properties of polytetrafluoroethylene(PTFE)-containing isotactic polypropylene(iPP)composites were investigated.In-situ fiber technology has achieved in the blending,the performance of the composite with in-situ fiber dispersed phase is more prominent.In this study,a one-step fiber-forming process was used to pre-mix and fibrillate the blended iPP/PTFE composite system.The study found that the in-situ microfibrillation of the composite system rheological properties have improved compared to iPP,the crystallization temperature increased slightly.Foaming experiments on composites revealed that the foaming properties of the in-situ microfibers composites were improved.Many extrusion foam processing parameters coupling effect.In order to explore the impact of process conditions in the foaming process characteristics and principles of action,use orthogonal experimental design of the research methods,the amount of foaming aids,foaming temperature and gas injection volume were studied,obtained the impact of the law in the foaming process and the principle of action.This study established a theoretical model called foaming efficiency to evaluate foaming performance.It can evaluate the nucleating agent on the foaming performance improvement principle by foaming efficiency.Foaming temperature in the foaming role is crucial,the cooler's performance is very important as the core of the temperature control equipment.This study aimed at the current service of melt cooler,put forward the idea of improvement.Combined with the flow and heat transfer characteristics of high viscosity polymer melt,theoretical calculation equations of pressure drop and heat transfer are introduced.Doing numerical simulation to optimize the idea and get the best solution.