Abstract: A method of preparing an electret by saturating a nonwoven fabric with a liquid, such as water, and removing the liquid via suction to generate charges by friction between the fabric fibers and the liquid is described. The saturating can be carried out, for example, by impinging the bottom side of the fabric with a jet or jets of water while the fabric is being pulled under a solid roller. Excess water can also be applied during a water quenching step of a meltblowing or spunbonding process. An apparatus for preparing an electret according to the presently disclosed methods is also described.

Abstract: A method of preparing an electret by saturating a nonwoven fabric with a liquid, such as water, and removing the liquid via suction to generate charges by friction between the fabric fibers and the liquid is described. The saturating can be carried out, for example, by impinging the bottom side of the fabric with a jet or jets of water while the fabric is being pulled under a solid roller. Excess water can also be applied during a water quenching step of a meltblowing or spunbonding process. An apparatus for preparing an electret according to the presently disclosed methods is also described.

Abstract: Fiber coated nonwoven laminates and methods and lines for making the same are disclosed. The fiber coated nonwoven laminates can have a fiber web layer that can range from about 0.01 g/m2 to about 100 g/m2. The lines for forming the nonwoven laminates can include a die body that includes an extruder therein for extruding fibers and a collector disposed below the die body. A substrate feeder can be provided for directing a substrate over the collector between the die body and the collector. The substrate is combinable with the extruded fibers to form the nonwoven laminate. An electric field can be created between the die body and collector to direct the fibers toward the collector as the substrate passes over the collector to collect the fibers on the substrate.

Abstract: This invention is directed towards a porous composite having an inlet face and an exit face and further comprises intermingled meltblown fibers and staple fibers which define a density gradient from coarse pores at the inlet face to fine pores at the exit face.

Abstract: A web or film is electrostatically charged by sequentially subjecting the web or film to a series of electric fields such that adjacent electric fields have substantially opposite polarities. Both a method and apparatus are disclosed for charging the web or film.

Abstract: A staple fiber web is disclosed which contains pleats having staple fibers which are commingled with staple fibers from adjoining pleats. The commingling permits denser packing of pleats on the web and increases filtering efficiency and stability of the web. Methods of manufacturing the pleated staple fiber web are disclosed.

Abstract: A web or film is electrostatically charged by sequentially subjecting the web or film to a series of electric fields such that adjacent electric fields have substantially opposite polarities. Both a method and apparatus are disclosed for charging the web or film.

Abstract: A web or film is electrostatically charged by sequentially subjecting the web or film to a series of electric fields such that adjacent electric fields have substantially opposite polarities. Both a method and apparatus are disclosed for charging the web or film.