The Preparation Of Needle Punching Non-wovens Hot Pressing Plates And The Study Of Waste Filter Bag Reutilization

With the development of society,traditional single materials have been unable to meet the needs of modern science and technology due to their own limitations.The development of composite and functional materials has become an inevitable trend of development,while fibre-reinforced composites meet people’s needs and have developed rapidly in recent years.In the traditional production of fiber-reinforced materials,polymer resin particles are melted to infiltrate fibers,thereby producing a composite material.In related research,many scholars used nonwoven web process and needle punched to make resin/reinforcing fiber web.It is beneficial to the full infiltration of the molten resin to the fibers during hot press molding.This technical route also has reference guiding significance for the recycling of waste fiber materials.In the hot-pressed composite sheet of needle punched material,polypropylene fiber is mostly used as the matrix fiber,but the prepared composite sheet has general mechanical properties and cannot be used for load-bearing and supporting materials.In this paper,polyester fiber is used to prepare polyester needle punched composite sheet with better mechanical properties,and the reinforcement effect of glass fiber base fabric is studied.Design a single factor test to study the effects of the number of layups,hot pressing pressure,temperature,and time on the mechanical properties and crystalline structure of the polyester/glass fiber needle punched hot pressing sheet.The best hot pressing process parameters are 7layers of lamination,8MPa of hot pressing pressure,260℃of hot pressing temperature,5min of hot pressing time,respectively.The tensile strength,bending strength and impact strength of the composite sheet are 93.7MPa,131.6MPa,94.8kJ/m~2,At this time,PET resin has the smallest crystallinity and grain size,which are 37.1%and 135?,respectively.With the increase of hot pressing pressure,temperature and time,the tensile,bending and impact properties of the polyester/glass fiber needle punched hot pressing sheet all show the trend of increasing first and then decreasing.When the hot pressing process parameters change,the impact strength of the composite sheet is the largest,and the tensile strength is the smallest.Among the three hot pressing parameters,the change of hot pressing time has the greatest effect on the mechanical properties of the composite sheet.When the time is extended from 5 minutes to 10 minutes,the impact,bending,and tensile strengths drop by 31.52%,19.65%,and 12.05%,respectively.Based on the research of polyester needle punched hot-pressed sheet,further try the forming process of waste filter bag regenerated fiber hot-pressed sheet.With reference to the recycling process of waste clothing machinery,the process of opening waste filter bags was studied.The waste filter bags were crushed and opened to obtain regenerated PPS fibers.The basic properties of the fibers were analyzed and tested.Then they were mixed with polyester fibers and hot pressed.Into plates.The results are as follows:The fragments of filter bags obtained by mechanical crushing vary in size,and the cutting equipment and process need to be further optimized.Most of the regenerated PPS fibers obtained by opening are in the form of single fibers,but part fiber are entangled to form agglomerates due to the adhesion between the fibers.Among them are unbroken filter bag fragments and dust impurities.Compared with the recycling of waste clothing machinery,the mechanical opening process of waste filter bags used in this topic uses dry dust removal instead of water washing,which removes most impurities on the fiber surface and avoids waste of water resources and pollution.Compared with pure PPS fiber,the surface of the regenerated fiber has gully-like damage,the diameter distribution is larger,and the tensile properties drop by about 20%.A small portion of the fibers undergo thermal oxidation reactions,but the thermal properties have not changed significantly.Attempt to hot-press regenerated PPS fiber into a sheet,and study the effect of hot-press forming after mixing with polyester fiber.It is concluded that the density,thickness and tensile strength of recycled PPS/polyester fiber hot-pressed sheet are less than that of recycled PPS fiber hot-pressed sheet.