Research On Technology And Equipment Of PVA Hydrosols' Drying And Forming Using The Drum Dryer

As a kind of environment-friendly packing material, PVA water soluble film is used to conquer the problem of white pollution caused by common plastics, as it can be degraded. At present, the film was almost made by means of casting on steel band, and it can be used widely in packaging bags, embroideries, wig fabrication and so on. But the quality of the film can't meet the need of water transfer printing, because of the limitation of production machineries and technics.In order to solve the problem and to enlarge the application areas of PVA water soluble film, the drum casting method was brought out to produce the PVA water soluble film.In this paper, theoretical analysis about the technology of using PVA Hydrosols to make film by drum casting was carried out, and experiment about producing PVA water soluble film using dip coating by one single drum was done.Firstly, drying disciplines about using drum to make film was researched. Given temperature, humidity and air flow rate of the environment are invariable, the process of forming and drying film was studied by changing the viscosities of PVA hydrosols and the temperatures of the drum, then regression analysis was adopted; Page equation was used to obtain the drying equation of drum casting by fitting the datum of the experiment, then the relations between water ratio and time in the process of drum drying of making PVA water soluble film was obtained.Secondly, the technological parameters of making film by drum casting are coupled. So the quadric regression orthogonal combination was adopted to design the experiment.With EXCEL to deal with the datum which were derived in the experiment, the regression equation was established with optimized methods such as comprehensive evaluation, penalty function method, then the optimized and combined technological parameters were obtained ultimately.Lastly, the problems in the process of making film by drum casting were studied and analyzed, and then the improved experiment was proposed.The drum drying disciplines and coarse theories in the process of making the film were obtained, through this study, which has theoretical and practical guidance in improving the equipments of making PVA water soluble film.