Abstract: A single-layer spunbonded air-filtration web including meltspun autogenously bonded electret fibers with an Actual Fiber Diameter of from 3.0 microns to 15 microns. The air-filtration web exhibits a ratio of mean flow pore size to pore size range of from 0.55 to 2.5. Also disclosed are methods of making such webs, and methods of using such webs to perform air filtration.

Abstract: A single-layer spunbonded air-filtration web including meltspun autogenously bonded electret fibers with an Actual Fiber Diameter of from 3.0 microns to 9.0 microns. The air-filtration web exhibits a mean flow pore size of from 8.0 to 19 microns and exhibits a ratio of mean flow pore size to pore size range of from 0.55 to 2.5. Also disclosed are methods of making such webs, and methods of using such webs to perform air filtration.

Abstract: A method of making a fluorinated fibrous web, which method includes providing a nonwoven web 22 that contains polymeric fibers, creating a plasma that contains fluorine atoms at a first location 14, and contacting the nonwoven web with products from the plasma at a second location 26 remote from the first location 14. The method avoids exposure of the web to the plasma and hence expands the manufacturing processing window. Webs so fluorinated have a different C3F4H+ to C2F5+ ratio when compared to locally fluorinated webs having similar levels of surface fluorination. The remote fluorinated webs can be subsequently charged electrically to provide a good performing electret filter 40 suitable for use in an air purifying respirator 30. Webs fluorinated in accordance with this invention also may exhibit good performance even after being “aged” at high temperatures.

Abstract: A method of making a fluorinated fibrous web, which method includes providing a nonwoven web 22 that contains polymeric fibers, creating a plasma that contains fluorine atoms at a first location 14, and contacting the nonwoven web with products from the plasma at a second location 26 remote from the first location 14. The method avoids exposure of the web to the plasma and hence expands the manufacturing processing window. Webs so fluorinated have a different C3F4H+ to C2F5+ ratio when compared to locally fluorinated webs having similar levels of surface fluorination. The remote fluorinated webs can be subsequently charged electrically to provide a good performing electret filter 40 suitable for use in an air purifying respirator 30. Webs fluorinated in accordance with this invention also may exhibit good performance even after being “aged” at high temperatures.

Abstract: Apparatus and methods for delivering a heated fluid. The apparatus includes at least a preheat zone, an expansion zone, and an expanded zone comprising a plurality of trim heaters, at least one fluid flow-distribution sheet, and an outlet. The apparatus may be used for delivering the heated fluid onto a moving fluid-permeable substrate.

Abstract: Apparatus and methods for delivering a heated fluid. The apparatus includes at least a preheat zone, an expansion zone, and an expanded zone comprising a plurality of trim heaters, at least one fluid flow-distribution sheet, and an outlet. The apparatus may be used for delivering the heated fluid onto a moving fluid-permeable substrate.

Abstract: Apparatus and methods for delivering a heated fluid. The apparatus includes at least a preheat zone, an expansion zone, and an expanded zone comprising a plurality of trim heaters, at least one fluid flow-distribution sheet, and an outlet. The apparatus may be used for delivering the heated fluid onto a moving fluid-permeable substrate.

Abstract: A method of making a fluorinated fibrous web, which method includes providing a nonwoven web 22 that contains polymeric fibers, creating a plasma that contains fluorine atoms at a first location 14, and contacting the nonwoven web with products from the plasma at a second location 26 remote from the first location 14. The method avoids exposure of the web to the plasma and hence expands the manufacturing processing window. Webs so fluorinated have a different C3F4H+ to C2F5+ ratio when compared to locally fluorinated webs having similar levels of surface fluorination. The remote fluorinated webs can be subsequently charged electrically to provide a good performing electret filter 40 suitable for use in an air purifying respirator 30. Webs fluorinated in accordance with this invention also may exhibit good performance even after being “aged” at high temperatures.

Abstract: A method of making a fluorinated fibrous web, which method includes providing a nonwoven web 22 that contains polymeric fibers, creating a plasma that contains fluorine atoms at a first location 14, and contacting the nonwoven web with products from the plasma at a second location 26 remote from the first location 14. The method avoids exposure of the web to the plasma and hence expands the manufacturing processing window. Webs so fluorinated have a different C3F4H+ to C2F5+ ratio when compared to locally fluorinated webs having similar levels of surface fluorination. The remote fluorinated webs can be subsequently charged electrically to provide a good performing electret filter 40 suitable for use in an air purifying respirator 30. Webs fluorinated in accordance with this invention also may exhibit good performance even after being “aged” at high temperatures.

Abstract: Apparatus and methods for delivering a heated fluid. The apparatus includes at least a preheat zone, an expansion zone, and an expanded zone comprising a plurality of trim heaters, at least one fluid flow-distribution sheet, and an outlet. The apparatus may be used for delivering the heated fluid onto a moving fluid-permeable substrate.

Abstract: Apparatus and methods for delivering a heated fluid. The apparatus includes at least a preheat zone, an expansion zone, and an expanded zone comprising a plurality of trim heaters, at least one fluid flow-distribution sheet, and an outlet. The apparatus may be used for delivering the heated fluid onto a moving fluid-permeable substrate.

Abstract: An apparatus for producing meltblown webs includes a meltblowing die having a plurality of filament outlets, a collector for receiving filaments of polymeric material expelled from the filament outlets, and a first Coanda effect device positioned adjacent to the path of the filaments adjacent to the last filament outlet at an end of the meltblowing die. Methods of forming meltblown webs using such an apparatus are also disclosed.

Abstract: Herein are disclosed apparatus and methods for delivering a heated fluid. The apparatus comprises at least a preheat zone, an expansion zone, and an expanded zone comprising a plurality of trim heaters, at least one fluid flow-distribution sheet, and an outlet.

Abstract: A method of making a fluorinated fibrous web, which method includes providing a nonwoven web 22 that contains polymeric fibers, creating a plasma that contains fluorine atoms at a first location 14, and contacting the nonwoven web with products from the plasma at a second location 26 remote from the first location 14. The method avoids exposure of the web to the plasma and hence expands the manufacturing processing window. Webs so fluorinated have a different C3F4H+ to C2F5+ ratio when compared to locally fluorinated webs having similar levels of surface fluorination. The remote fluorinated webs can be subsequently charged electrically to provide a good performing electret filter 40 suitable for use in an air purifying respirator 30. Webs fluorinated in accordance with this invention also may exhibit good performance even after being “aged” at high temperatures.

Abstract: Methods and apparatus for meltblowing utilize an auxiliary manifold to dispense a fluid between an orifice of a die that is expelling polymeric fibers and an exit of a duct that is dispensing a secondary flow of gas onto the fibers. The fluid dispensed from the auxiliary manifold reduces a recirculation zone of the secondary flow between the exit and the orifice that, absent the fluid from the manifold, results in errant fibers that are blown back into the face of the die by the recirculating secondary flow.

Abstract: A method of making a fluorinated fibrous web, which method includes providing a nonwoven web 22 that contains polymeric fibers, creating a plasma that contains fluorine atoms at a first location 14, and contacting the nonwoven web with products from the plasma at a second location 26 remote from the first location 14. The method avoids exposure of the web to the plasma and hence expands the manufacturing processing window. Webs so fluorinated have a different C3F4H+ to C2F5+ ratio when compared to locally fluorinated webs having similar levels of surface fluorination. The remote fluorinated webs can be subsequently charged electrically to provide a good performing electret filter 40 suitable for use in an air purifying respirator 30. Webs fluorinated in accordance with this invention also may exhibit good performance even after being “aged” at high temperatures.

Abstract: Manifolds are designed to deliver fluid through multiple orifices of the manifold such that for a given inlet fluid pressure the fluid being output from the multiple orifices has a desired mass flow profile. The desired mass flow profile includes a desired mass flow rate and a desired direction and distribution of flow in three-dimensional space. The manifold is first modeled as a two-dimensional representation to determine manifold parameters necessary to achieve the desired mass flow profile within the two dimensions. Then, the manifold is modeled as a three-dimensional representation based on the parameters previously determined for the two-dimensional representation to determine manifold parameters of the third dimension that are necessary to achieve the desired mass flow profile within the three dimensions.

Abstract: Melt blown or spun bond nonwoven webs are formed by flowing fiber-forming material through a die cavity having a substantially uniform residence time and then through a plurality of orifices to form filaments, using air or other fluid to attenuate the filaments into fibers and collecting the attenuated fibers as a nonwoven web. Each die orifice receives a fiber-forming material stream having a similar thermal history. The physical or chemical properties of the nonwoven web fibers such as their average molecular weight and polydispersity can be made more uniform. Wide nonwoven webs can be formed by arranging a plurality of such die cavities in a side-by-side relationship. Thicker or multilayered nonwoven webs can be formed by arranging a plurality of such die cavities atop one another.

Abstract: Melt blown or spun bond nonwoven webs are formed by flowing fiber-forming material through a die cavity having a substantially uniform residence time and then through a plurality of orifices to form filaments, using air or other fluid to attenuate the filaments into fibers and collecting the attenuated fibers as a nonwoven web. Each die orifice receives a fiber-forming material stream having a similar thermal history. The physical or chemical properties of the nonwoven web fibers such as their average molecular weight and polydispersity can be made more uniform. Wide nonwoven webs can be formed by arranging a plurality of such die cavities in a side-by-side relationship. Thicker or multilayered nonwoven webs can be formed by arranging a plurality of such die cavities atop one another.

Abstract: Melt blown nonwoven webs are formed by supplying fiber-forming material to a planetary gear metering pump having a plurality of outlets, flowing fiber-forming material from the pump outlets through a plurality of inlets in one or more die cavities, and meltblowing the fiber-forming material. Each die cavity inlet receives a fiber-forming material stream having a similar thermal history. The physical or chemical properties of the nonwoven web fibers such as their average molecular weight and polydispersity can be made more uniform. Wide nonwoven webs can be formed by arranging a plurality of such die cavities in a side-by-side relationship. Thicker or multilayered nonwoven webs can be formed by arranging a plurality of such die cavities atop one another.