Study on the microfiber attenuation in melt-blowing airflow field. Issue 7 (April 2023) - Wanli, Han
Melt blowing (MB) is a process for producing microfiber or nanofiber using high-velocity air to attenuate the polymer jet. Compared to research on the melt-blowing airflow field analysis, the melt blown die optimization, and new materials development, little work has been done on fiber attenuation and whipping in the melt-blowing process. In this study, the airflow field distribution and turbulence fluctuation of the melt-blowing die are investigated using numerical simulation. The fiber motion process is simulated with the bead-viscoelastic element model and obtained using the high-speed camera. The underlying mechanisms leading to melt-blowing fiber attenuation have been discussed. The results show that the airflow field can be separated into three regions. The turbulent fluctuations in Regions I are related to the fiber whipping in the melt-blowing process. The fiber motion in Regions II and III are unsteady, resulting in higher fiber attenuation. Region II is the main zone of fiber attenuation where the fiber whipping increases and the drawing ratio is the largest. The fluctuation of air velocity causes fiber whipping which plays an important role in fiber attenuation. Experimental results of fiber diameter reduction and fiber motion are consistent with the simulation results.