Study of the Uniformity of Nonwoven Fabrics and Their Repellency and Barrier Performance Characteristics, 1990 Nonwovens Conference Proceedings

A study was carried out to determine the repellency properties, as well as the uniformity, in terms of weight, thickness and air permeability Of eight nonwoven fabrics consisting of spunbonded polyethylene, a spunbonded composite of polyester and wood pulp, and laminates of spunbonded/melt blown/spunbonded polypropylene fabrics in both finished and unfinished form. Significant differences in fabric weight, thickness and air permeability were found in the machine direction (MD) and cross-machine direction (CD) for fabric weight, thickness and air permeability. Cyclical trends in the properties of weight and air permeability in the MD were noted. This revealed that the relatively large effects of CD variability were not constant along the length of the rolls. Also, significant interaction effects were found between the factors of location in the MD and location in the CD.

In the qualitative comparisons among fabrics, all the repellent finished fabrics exhibited excellent water spray and oil repellency ratings. The regular and corona treated "Tyvek" fabrics, unfinished "SMS" finished and fabrics and the repellent finished Sontara fabric did not allow any water to penetrate during the water impact Penetration test. The Sontara fabrics had the highest air permeability followed by the "SMS" fabrics and finally the "Tyvek" fabrics which had no measurable air Permeability with the Gurley Permeometer.