| abstract |
The filtration medium is of a composite construction and includes a liquid permeable nonwoven fabric substrate and a liquid permeable film layer of polyolefin resin adhered to one surface of the nonwoven fabric substrate and forming one of the exposed surfaces of the filtration medium. An antimicrobial agent is incorporated in the film layer. Preferably, the liquid permeable film layer is a polyolefin film having a plurality of liquid permeable apertures extending therethrough. The antimicrobial agent is blended with the polyolefin resin prior to extrusion of the film so that it is present throughout the film layer. The antimicrobial agent may be present in the film layer at a concentration of from 0.01% to 5% by weight, based on the weight of the film layer. |