The NonWoven Industry
The nonwovens and textile industries are very similar to the filtration industry as nonwovens and textiles are widely used as filtration media. Nonwovens also include personal products such as tissues and toilet paper. The nonwovens and textile industries use PMI testing equipment and analytical services for a wide variety of applications, some of which are highlighted below.
Many nonwovens are used as "high-tech" fabrics, i.e., fabrics with novel properties. The classic example is Gore-Tex™ and similar materials, which are utilized for applications such as surgical attire and waterproofing. Key among Gore-Tex™'s unique properties is pore size. The pore size and other properties of Gore-Tex™ allow the passage of water vapor ("breathability"), but not bulk water, resulting in its waterproof feature. Characterization of pore size is therefore key.
Another classic application is characterization of adsorbent fabrics, i.e., fabrics specially designed to "move" or transport various types of moisture from one place to another. One factor in determining moisture transport is the interaction of the material with the liquid - the same physical phenomenon upon which porometry is based. As a result, porometry is a good index of performance and properties of adsorbent fabrics. Also pore volume determines the holding capacity for liquids. PMI's Liquid Extrusion Porosimeter is ideal for characterization of pore volume of nonwovens which are normally very soft.
Also in this group of materials are geotextiles, as they are very similar to nonwovens/textiles. PMI manufactures instruments which allow researchers to predict the size of particles, such as dirt, which pass through the geotextile. This geotextile acts as a barrier for particles of a given size, and allows free passage of smaller particles or fluids, e.g., water. Knowing the pore size distribution from the porometer is a direct test for the geotextiles performance in the field.