Hydroentangled polymer nonwovens: Prediction of jet streaks and surface roughness

Here, the dynamic model of polymer fibers in hydroentanglement is used to predict the appearance of the so-called jet streaks and surface roughness. The mechanism of formation of jet streaks is explained. It is shown that the staggered two-row water jets which are widely used in industry help to optimize surface roughness and reduce the jet streaks. It is also shown that the jet width ratio plays an important role in minimizing the surface roughness at different jet pressures. Furthermore, a novel numerical method of re-construction of the 3-D surface topography from discrete data is developed to visualize the jet streaks. Also, in the experiments of this work, the optical images of jet streaks on hydroentangled polymer nonwovens are analyzed. The streaks period is measured by using the Fast Fourier Transform (FFT) and the surface topography is visualized by using optical profilometer. The predicted optimal jet width ratio is compared to the experimental results and a good agreement is found.