Multivariable Studies of Nonwoven Fabrics

The performance characteristics of nonwoven fabrics have been studied as a function of fiber properties, binder properties, and web construction. The particular type of non-woven selected for study was a web of random-laid base fibers in which randomly placed thermoplastic fibers provide the bonds. The responses studied were those related to rupture, elastic, and handle (aesthetic) properties. Fourteen variables were investigated: Base fiber linear density, base fiber staple length, amount of crimp in base fiber, post-yield extension of base fiber, type of binder, linear density of binder, staple length of binder, binder concentration, mass per unit area of nonwoven, amount of needle looming, number of laminations per web weight, pressure of bonding, temperature of bonding, and time of bonding. The performance characteristics measured as a function of these variables were maximum tenacity at dry and wet conditions, elongation at dry and wet conditions, tear strength, abrasion resistance, elastic modulus at dry and wet conditions, proportional limit at dry and wet conditions, crease recovery, bending length, flexural rigidity, bending modulus, bulk density, and air permeability. Crimp, linear density, and staple length of the base fiber influence rupture, elastic, and handle properties, as expected. Binder properties, other than type, have no effect due to the destruction of the fiber in the bonding process. Bonding conditions, particularly pressure and temperature, are extremely influential in all types of properties. These variables govern the effectiveness of the bonds. Concentration of binder is extremely important to all types of responses since it governs the number and distribution of bonds. Needle looming affects only rupture properties.