Abstract: Various embodiments of an exhalation valve and a filtering face mask that includes such exhalation valve are disclosed. The exhalation valve can include a valve seat and a valve flap disposed over a seal surface and an orifice of the valve seat. The valve flap is adapted to be sealed against the seal surface of the valve seat when the exhalation valve is disposed in a closed configuration such that fluid is prevented from flowing through the valve seat. The orifice of the valve seat can include a substantially circular shape in a plane defined by a first major surface of the valve seat. Further, the seal surface can circumscribe the orifice and can include a substantially noncircular shape in the plane defined by the first major surface of the valve seat.

Abstract: A pleated air filter media is provided. The pleated air filter media comprises a plurality of upstream linear bridging filaments that are extrusion-bonded to at least some of a plurality of upstream pleat tips of a fibrous web, and a plurality of downstream continuous-contact filaments that are extrusion-bonded to a downstream face of the fibrous web. Methods of making and using the same are also provided.

Abstract: A flat fold filtering face piece respirator 10 that includes a mask body 12 and a harness 14. The mask body 12 includes a filtering structure 16 that contains a cover web 48, 50 and a filtration layer 52 that contains electrically-charged microfibers. The filtering structure 16 is folded over upon itself in a nose region 32 of the mask body 12 to be at least 1 centimeter or more wide and to extend across the upper perimeter of the mask body in a generally straight line when the respirator is in the folded condition. The filtering structure 16 has a deflection greater than about 0.5 millimeters and has a recoverability of at least 40% in the folded condition. A mask body having this construction is beneficial in that it does not need to use a nose foam to obtain a snug fit over the nose.

Abstract: A flat fold filtering face piece respirator 10 that includes a mask body 12 and a harness 14. The mask body 12 includes a filtering structure 16 that contains a cover web 48, 50 and a filtration layer 52 that contains electrically-charged microfibers. The filtering structure 16 is folded over upon itself in a nose region 32 of the mask body 12 to be at least 1 centimeter or more wide and to extend across the upper perimeter of the mask body in a generally straight line when the respirator is in the folded condition. The filtering structure 16 has a deflection greater than about 0.5 millimeters and has a recoverability of at least 40% in the folded condition. A mask body having this construction is beneficial in that it does not need to use a nose foam to obtain a snug fit over the nose.

Abstract: A method for imparting an electrostatic charge to a nonwoven fibrous web 20. The fibrous web 20 is contacted with a liquid solution that includes water and a non-aqueous water soluble component, followed by drying 31. The resulting dried product is an electret article 43 that could be used as an air filter in, for example, a respirator 50.

Abstract: A method for imparting an electrostatic charge to a nonwoven fibrous web 20. The fibrous web 20 is contacted with a liquid solution that includes water and a non-aqueous water soluble component, followed by drying 31. The resulting dried product is an electret article 43 that could be used as an air filter in, for example, a respirator 50.

Abstract: A method of charging fibrous webs with nonaqueous polar liquids. A web 20 that contains nonconductive fibers is wetted with a nonaqueous polar liquid 14. The web 20 is then substantially dried 22 to provide a fibrous electret web. The fibrous electret web can be used as a filter in a filtration face mask 40 that is adapted to cover the nose and mouth of the wearer. The present method has the advantage over known charging methods in that the nonaqueous liquid requires less energy for drying than is required for aqueous liquids. Additionally, many filter webs can be directly wetted with nonaqueous liquids, which cannot be easily wetted with aqueous liquids.

Abstract: An apparatus for charging fibers that contain a nonconductive polymer. A polar liquid 32, 34 is sprayed onto free-fibers 24, and the free-fibers 24 are then collected to form an entangled nonwoven fibrous web 25 that may contain a portion of the polar liquid. The nonwoven web 25 is then dried 38. By applying an effective amount of polar liquid 32, 34 onto the nonconductive free-fibers 24 before forming the nonwoven web 25, followed by drying 38, the individual fibers 24 become charged. The apparatus can enable the fibers 24 to be charged during web manufacture without subsequent processing.

Abstract: A method for imparting an electrostatic charge to a nonwoven fibrous web 20. The fibrous web 20 is wetted with a wetting liquid 24, followed by being saturated with an aqueous polar liquid 30 and drying 31. The resulting dried product is an electret article 43 that could be used as an air filter in, for example, a respirator 50.

Abstract: A method and apparatus for charging fibers that contain a nonconductive polymer. A polar liquid 32, 34 is sprayed onto free-fibers 24, and the free-fibers 24 are then collected to form an entangled nonwoven fibrous web 25 that may contain a portion of the polar liquid. The nonwoven web 25 is then dried 38. By applying an effective amount of polar liquid 32, 34 onto the nonconductive free-fibers 24 before forming the nonwoven web 25, followed by drying 38, the individual fibers 24 become charged. The method and apparatus enable the fibers 24 to be charged during web manufacture without subsequent processing.

Abstract: Insolubilized enzyme particulates are located on the upstream surface of a filtration layer of a filtering element which can be used in a cartridge filter. Employed in a recycling flow reaction system at relatively high flux rates, the cartridges are useful for conducting catalyzed chemical reactions of dissolved solutes, for example, esterifications, isomerizations, oxidations, reductions, and cyclizations.