Abstract: A dimensionally more stable mat is made from a less dimensionally stable mat by saturating the mat with a binder and passing and compressing the mat between a pair of squeeze rolls to remove binder from the mat. At least one of the rolls has a series of annular grooves therein spaced apart along the length of the roll and across the width of the mat whereby as the mat is passed between the rolls a first and a second series of longitudinally extending bands are formed in the mat having different average binder concentrations. The second series of bands, formed in the mat at the annular grooves of the roll, has an average binder concentration greater than that of the first series of bands.

Abstract: Provided is a filter medium comprised of core-sheath fibers wherein the sheath portion comprises an effective amount of antimicrobial agent. Preferably, all fibers of the filter medium comprise such core-sheath fibers, so that every fiber of the filter medium contains the antimicrobial agent to effectively deter bacterial growth.

Abstract: A dimensionally more stable mat is made from a less dimensionally stable mat by saturating the mat with a binder and passing and compressing the mat between a pair of squeeze rolls to remove binder from the mat. At least one of the rolls has a series of annular grooves therein spaced apart along the length of the roll and across the width of the mat whereby as the mat is passed between the rolls a first and a second series of longitudinally extending bands are formed in the mat having different average binder concentrations. The second series of bands, formed in the mat at the annular grooves of the roll, has an average binder concentration greater than that of the first series of bands.