Effect of Bonding Variables in Thermal Bonding of Polypropylene Nonwovens

The aim of this research was to investigate the effect of some of the process variables on the structure and properties of the webs in a thermal point bonding process. The main objectives were to understand the changes taking place in the fiber structure due to applied heat and pressure, the effect of bond area and bond size on fiber morphology, and the physical properties of the web. Thermally bonded carded webs were produced and characterized in order to determine the role of bond area and bond size on strength and stiffness of the point bonded fabrics and fiber morphology. The webs were also characterized to see the changes taking place in fiber morphology on thermal bonding. It was observed that the bond strength increases with bond area and bond size. The effect of bond area and bond size on fiber morphology were negligible. Significant morphological differences were observed in the bonded and the unbonded regions of the thermally bonded webs. To see how the staple fiber studies relate to the behavior of continuous filaments, similar sets of samples were produced and characterized using the spunbond system. The observed trends for properties with respect to bonding conditions were similar for spunbond samples. However, actual values of tensile and other physical properties were much higher for spunbond webs.