Quantification of binder fibres in needle-punched nonwoven and its influence on physical-mechanical-functional properties of an air filter media

A nonwoven filter (viscose fibres) with an optimal design has been developed by controlling the binder fibres (fibres in the vertical direction) in the needle-punched nonwoven. Box and Behnken design in conjunction with 3D surface analysis hasbeen used to study the effect of punch density, needle penetration depth and stroke frequency, considering the percentage of binder fibres in the overall structure on thickness, tenacity, air permeability and filtration efficiency of the filter. In this work, all the above properties are explained in the light of the considered structural index 'percentage of binder fibres'. It is observed that the percentage of binder fibres increases with the increase of all three considered punching parameters. The thickness and tenacity are found to be decreased and increased respectively, with the increase of binder fibre percentage. The air permeability initially decreases and then increases with the increase in the percentage of binder fibres, whereas the filtration efficiency showsthe opposite trend.