Study And Application On Engineering Model Of Melt Spinning Of Fine Denier Poy Polyester Filament

As the mainstream development of differential fiber, fine denier and superfine denier polyester filament has experienced a great development for many decades. It is very significant for us to study the theory of melt spinning more detailed. Currently, the simulation of melt spinning of fine denier polyester filament can not be explained with the result of the previous study, which mainly on the research of the melt spinning process of PET, or the influence of high-speed spinning or the dynamic of melt spinning of polyester staple fiber. It is not suitable to use the previous dynamic model for simulating the fine denier polyester filament now. Therefore, a basic model which is suitable for fine denier polyester filament spinning was established through converse fitting parameters in this thesis. The model was verified through experimental and online testing data, and made it be the guidance of new products development, spinning conditions optimization and filament properties predicting. The research was expected to provide a basic theory and a mathematical model for optimizing production technique and manufacturing high quality fine denier polyester filament.The dynamic melt spinning model was used to describe the monofilament model of polyester filament melt spinning with relatively integral model parameters and the temperature, velocity, velocity gradient, spinning stress, orientation and crystallinity of filament along the spinline, which were in different spinning conditions of take-up velocity, spinning temperature and quenching process, were simulated and depicted respectively by using of the fourth order Runge-Kutta algorithm. Besides, the results of the simulation were controlled within10percent error comparing with the experimental data.The vitrification distance as a equation of the take-up speed and mass throughput was established and the annealing technology as well as the spinneret technology had been improved. The result of the formulation showed that it is very convenient to decrease the orientation and crystallinity as well as the cooling speed, velocity gradient and tension of polyester filament by controlling the spinning condition appropriately such as reducing the take-up speed and quench air velocity while increasing the melt temperature, the annealing temperature and quench air temperature. Then the parameters of fine denier polyester POY melt spinning process at practical production line were adjusted according to the simulation results. In addition, the filament quality was compared with that before and after adjustment. It is observed that the fiber strength, strength irregularity, elongation, elongation irregularity and Uster irregularity were improved through adjusting the process of melt spinning.Furthermore, in order to establish the distribution model of the quench air temperature (Tair) and the quench air velocity (Vair) for fine denier POY multifilament, the filament is divided into a number of segments as a micro-unit, accounting for mass conservation and energy conservation of the filament and surrounding condition. The dynamic model of fine denier polyester multifilament was presented by the matrix method of the model of single filament. Thus, the differences of the filament diameter, temperature, velocity gradient, orientation and the crystallinity as well as the quench air velocity and temperature at different position of spinline were investigated and simulated.In addition, the relationship among the melt spinning process, materials structure and filament properties had been formulated by a large amount of experimental data of orientation and elongation. Therefore, the influence of process on properties was investigated directly by the performance prediction model. Weight factor expressions for EYS1.5and CVEYS1.5were formulated, through which properties and technology optimizations can be predicted within10percent error, also it could be used to provide effective guidance for practical production.An integrated computer simulation software was formed finally, based on the models that had been established above, using C#and together with the technology of digital image manipulation. The simulation software was used by fiber spinning plant to describe the process of melt spinning of the fine and superfine denier polyester filaments, as well as spinning conditions optimization and properties prediction of novel or traditional product. It is illustrated that the practicality and feasibility of the models established in this thesis had been improved significantly.