Abstract: Method and device for manufacturing a flat textile structure in which two melts of at least two polymer materials are changed to the form of fibers with the aid of a spinning device and in which fibers are then combined and then solidified. The spinning device consists of a spinning rotor and the polymer materials employed have an charge difference of at least ten unit charges. The two materials are first melted separately from one another. Each melt, by means of a distributor device, is then fed to a group of outlet openings of a spinning rotor unmixed. The fibers emerging from the outlet openings are then stretched and combined to form a common flat structure with the flat structure then being charged triboelectrically by an aftertreatment.

Abstract: A method for post-treating a laminated precursor nonwoven web which includes layers of thermoplastic man-made fibers and at least one layer of cellulose-based staple natural fibers, including consolidating the web longitudinally and thereby reducing the maximum pore size measure of the web. The precursor web and the resultant consolidated nonwoven web are also disclosed, as is utilization of the product web in medical uses.

Abstract: A method for post-treating a laminated precursor nonwoven web which includes layers of thermoplastic man-made fibers and at least one layer of cellulose-based staple natural fibers, including consolidating the web laterally and thereby reducing the maximum pore size measure of the web. The precursor web and the resultant consolidated nonwoven web are also disclosed, as is utilization of the product web in medical uses.

Abstract: An electret filter formed by laminating a plurality of network electret film-split fiber fleeces having a different mesh size. It exhibits a high collecting efficiency with a very small pressure loss and without any appreciable fiber dropping, or any channeling.

Abstract: Disclosed are a process for producing a tubular nonwoven fabric and tubular nonwoven fabrics produced by the same. In the process, a web is formed on a first rotating cylinder by catching fibers carried to the surface of the first rotating cylinder by a fluid, the web is transferred to a second rotating cylinder, a tube of the transferred web is formed on and around the second rotating cylinder, and the tube is drawn in the axial direction of the second rotating cylinder to form a tubular nonwoven fabric. The tubular nonwoven fabric with a high unit weight can be produced without elongating or breaking the nonwoven fabric, and the diameter of the tubular nonwoven fabric can be freely changed.

Abstract: An oily mist resistant electret filter media is provided. The filter media includes polypropylene electret fibers and a melt processable fluorochemical additive. The additive has a melt temperature of at least 25.degree. C. and a molecular weight of about 500 to 2500. Also provided is a method for filtering particulate material from air containing oily aerosol particles.

Abstract: The improved nonwoven fabric in an electret state is composed of monofilaments with an average fiber diameter of 0.5-100 .mu.m that are formed of a polymer composition containing no more than 1 mol % of polar groups; the fabric has a weight of 5-100 g/m.sup.2, a bulk density of 0.05-0.40 g/cm.sup.3 and an average surface charge density of at least 0.1.times.10.sup.-9 C/cm.sup.2. This nonwoven fabric is capable of efficient dust collection and its trapping ability is retained for a prolonged time even in a hot and humid condition. Also disclosed are a process for producing this nonwoven fabric, as well as a filtering and an air masking material which are composed of that nonwoven fabric.

Abstract: Disclosed is a filter sheet material for passenger cabins in motor vehicles, especially for the removal of unpleasant exhaust fumes, whereby on one and the same air permeable support material, a particle-filtering layer as well as an adsorption filter layer is provided. The adsorptive material in the adsorption filter layer is selected from active carbon particles, activated carbonized carbon particles, molecular sieves, porous polymer adsorbers and carbonized ion-exchangers. The particle filtering layer comprises a micro-fibre agglomeration.

Abstract: Filtration material comprising a web comprising meltblown fibers and staple, electrically charged fibers randomly dispersed among the meltblown fibers. The filtration material can be formed in planar configurations and in configurations other than planar. Non-planar configurations can extend the useful working area for a given filter element's cross-section without requiring an additional corrugating or pleating process step. The filtration material exhibits high strength and low pressure drop.

Abstract: An electret filter made of a resin whose angle of contact upon wetting with pure water is no smaller than 95 degrees, as well as an electret filter made of a resin whose angle of contact upon wetting with pure water has been adjusted to no smaller than 95 degrees by addition of silicone oil. Those electret filters have high trapping efficiency and their ability to trap particulates, especially cigarette smoke, will not deteriorate even if they are continuously used. Therefore, they can advantageously be used as filter media in many applications such as home and industrial air conditioners, air cleaners, fan heaters, vacuum cleaners, and air conditioning systems for common equipment.

Abstract: A portable air filter system is described for use in the home, offices, or other areas where it is desired to remove airborne particulate matter from the air. The air filter system includes an enclosure having an air inlet and outlet areas, removable air filter which is grounded, a fan for moving air from the inlet to the outlet through the filter, and an ionizer for supplying negative ions to the air exiting through the outlet. The filter includes electrostatically charged fibrous material in a removable cartridge.

Abstract: A film electret and an electret filter that contain a polar high-molecular weight compound and that provides a TSDC curve having a homocharge peak temperature of at least 95.degree. C. and a heterocharge peak temperature of at least 80.degree. C.

Abstract: A method for post-treating a precursor nonwoven web including consolidating the web laterally and thereby reducing the maximum pore size measure of the web. The resultant nonwoven web is also disclosed as is utilization of the product web as a filter.

Abstract: An adsorbent textile product comprising a compressed nonwoven unitary batt of textile staple fibers, a cured binder disposed substantially throughout said batt, and an adsorbent material disposed substantially within the confines of said batt. In the disclosed product, the binder serves to hold the batt in its compressed condition such that the adsorbent is mechanically retained within the confines of the batt. In this way, the outer surfaces of said adsorbent material remain effectively free of the binder so that the adsorptive qualities of the adsorbent are preserved. An intermediate product and a process for making the disclosed products are also disclosed.

Abstract: An electret sheet comprises a porous sheet made of a dielectric polymer and at least one solid material selected from the group consisting of organic materials, inorganic materials, and metallic materials, the porous sheet having the material spaced at various intervals and a method for the manufacture of the said electret sheet.

Abstract: A self-regulated system and method for controllably administering a therapeutic agent to a patient is disclosed. A therapeutic agent is driven by unidirectional electrostatic diffusion across a rate-controlling electret membrane. The diffused therapeutic agent is then delivered to a patient. The preparation of the electret membrane and therapeutic agent delivery apparatus are also disclosed.

Abstract: A filter element comprises a perforated metal tube on outer and inner sides of which filter layers are disposed. A plastic terminal disk 4 is disposed at an axial end of the tube and includes a metal fastening screw. A wire is embedded in the terminal disk and electrically connects the support tube with the fastening screw so that an electrical charge taken up from the liquid to be filtered is conducted away through the wire.

Abstract: Improved microfibrous filtration laminate comprising a highly permeable layer of a self-supporting nonwoven fabric which provided support for a layer of a randomly intertangled nonwoven mat of electret-containing microfibers of synthetic polymers are disclosed. The filtration laminate, which is particularly useful as disposable filter bags or as a lining material for disposable paper filter bags for vacuum cleaners, is characterized by thickness and handling characteristics approaching that of paper filter material typically use in disposable vacuum clean bags but having improved performance in the areas of an immediate, high particle capture efficiency, minimal flow restriction and long service life.

Abstract: A multilayer filter pack includes at least three adjacent layers of fibrous material, each of which is permanently electrically charged and not more than 10 mm thick. The upstream and middle layers are formed from fibers having a fiber diameter that decreases from layer to layer in the direction of flow and are arranged at a packing density that increases from layer to layer in the direction of flow. The third layer has a fiber diameter and packing density that is approximately equal to the fiber diameter and packing density of the first layer. The multilayer filter pack is particularly well suited for use in air-purifying systems and breath protection filters.

Abstract: An electret fiber sheet has polarized charges on its surface and preferably has charges in ordered orientation across it. The polarized charges are present in an amount of at least 7.times.10.sup.-11 C/cm.sup.2. Such sheets are formed to have a dust collecting efficiency. Sheets having an amount of polarized charge even as high as this are nevertheless stable when they have a maximum orientation energy of depolarization of at least 0.2 eV.Such an electret sheet can be obtained by a process comprising placing a fiber sheet between a non-contact type voltage-application electrode and an earth electrode confronting each other and supplying electricity (voltage>3 kV; current density>1.times.10.sup.-6 mA/cm.sup.2) between the electrodes, provided that the fiber sheet has a weight less than 80 g/m.sup.2 and a covering factor at least 60%.

Abstract: A fibrous electret filter better sustains electret filtration enhancement upon exposure to aerosol oils when made of fibers containing polypropylene and at least one percent by weight of poly(4-methyl-1-pentene). Even better stability is attained when the poly(4-methyl-1-pentene) content of the electret filter is ten percent by weight of total polyolefin. When used as an air filter, such as in a respirator, the electret filter has surprisingly better filtration performance than does a comparable electret filter made of 100% polypropylene fibers. The electret filter can be made either of melt-blown microfibers or of fibers of fibrillated film.

Abstract: A disk file 10 employs at least two filters 15,16 for removal of airborne particles, one filter 16 having a relatively coarse mesh and a relatively high rate of airflow and the other 15 having a relatively fine mesh and a relatively low rate of airflow. The fine filter 15 may be combined with a third, breather filter 30 which removes particles from air entering the disk enclosure. The main purpose of the coarse filter 16 is to remove the larger, more damaging particles very rapidly, thereby reducing the risk of damage to the surfaces of the disks 12.

Abstract: An electretized material for a dust filter which is made of an insulating polymer material such as polypropylene incorporated with a fatty acid metal salt in an amount of not less than 100 ppm in terms of the metal.

Abstract: The present invention relates to a continuous method for manufacturing an electret filter medium from dielectric material having an open or porous structure, said method comprising the steps of continuously feeding a web of dielectric material with a substantially closed dielectric foil adjacent to at least one major face thereof into a corona discharge device, reducing the thickness of the web of dielectric material and charging the web of reduced thickness dielectric material by means of a corona discharge and to apparatus for carrying out said method.

Abstract: An electrostatic filtration apparatus is used to significantly reduce contaminants in N.sub.2 O.sub.4 vapor and liquid at ambient temperatures. The apparatus uses an electret vapor filter having therein a stack of layers of electret material through which the N.sub.2 O.sub.4 must pass. A flow blocking filter is added to the electret liquid filter to insure a sufficient time for removal of contaminants by said electret material. The filter is constructed of chemically inert materials to prevent additional contaminants.

Abstract: An electretized material for a dust filter which is made of an insulating polymer material such as polypropylene incorporated with a fatty acid metal salt in an amount of not less than 100 ppm in terms of the metal.

Abstract: Disclosed is a high-performance electret comprising 60 to 99% by weight of a non-polar polymer, 0.5 to 39.5% by weight of a polar polymer and 0.5 to 20% by weight of at least one component selected from the group consisting of (A) a non-polar polymer modified with an unsaturated carboxylic acid or a derivative thereof, (B) a non-polar polymer modified with an unsaturated epoxy monomer and (C) a non-polar polymer modified with a silane monomer having an olefinically unsaturated bond.In this electret, a high charge density can be maintained stably over a long period, and this electret can be easily formed into a film. An air filter prepared from this electret is very excellent in the dust collecting efficiency.

Abstract: A reusable air filter system for providing permanent, self-charging, electrostatic filter stages that are easily cleanable for re-use. The filter system may be used on air conditioners, furnaces, and grease hoods. A frame is circumscribed about the edges of a plurality of polypropylene filter elements. At least one stage of the filter is three dimensional in shape and folded over on itself to retain its filtering characteristics and to provide a dual biasing device for use with the filter stages upstream of the three dimensional filter. The folded three dimensional filter is not creased, thus providing an additional biasing element in the filter system.

Abstract: A device is described for filtering zinc powder from an airstream which is exhausted from a galvanizing process. The device comprises an enclosed chamber to which the airstream is circulated for removal of zinc powder. The chamber has a horizontally disposed bottom surface in which there is a plurality of circular openings which are equally spaced about a vertical center axis and which lead to vertically disposed bag-type filters. An arm is coupled to a vertical drive shaft which is rotatable about the center axis. The arm is designed to move a circular cover from opening-to-opening to individually seal the openings from the chamber, so that the filters can be cleaned of zinc powder. The cover is freely mounted on the distal end of the arm such that the cover is supported on the bottom surface of the chamber as it moves in an arcuate pathway between the filter openings.

Abstract: A process of manufacturing an electrostatically charged filtration medium is disclosed. A web made of nonconductive thermoplastic fibers is contacted on each side with a more conductive web to form a combined web. The combined web is charged with electrically charged particles from corona charging elements on opposite sides of the web. The charging elements are operated at a voltage of from 5 to 25 kV but with opposite polarity.

Abstract: A filter assembly in an air cleaner includes a lower wire-form adapted to receive two opposite ends of a pliable filter material. Spaced wires on the lower wire-form enable manual forming of pleats in the filter material and define the tops of such pleats. A complementary upper wire-form is engageable with the lower wire-form and attached filter to define the bottoms of such pleats.

Abstract: An air filter assembly including an electret filter sheet of material which exhibits electrical charges of opposite sign on opposite faces thereof and a non-electret conventional filter sheet of material combined with and disposed upstream from the electret filter sheet of material, whereby particles of a large diameter are collected by the non-electret filter sheet of material and particles of a small diameter are collected by the electret filter sheet of material without causing clogging or air pressure loss.

Abstract: Method and apparatus for charging and collecting submicron particles. The particles are charged by a needle-to-plate ionizer having offset rows of needles which are spaced from the plate such that voltage gradients of 6 KV/cm and higher are achieved. Needle-to-needle spacing and effective area of the plate are such that a corona current having a density of at least 4 ma/m.sup.2 flows between the needles and the plate. Circuitry is provided that in combination with the ionizer quickly quenches arcs while maintaining the voltage across the ionizer. Charged particles are collected in a collecting section having a deflector electrode and a pair of collecting plates. The deflector electrode includes a conductor embedded in a dielectric material having a dielectric constant greater than 1, which dielectric material suppresses arcs between the deflector electrode and the collecting plates.

Abstract: A persistent electric charge is introduced into melt-blown fibers during the melt-blowing process. When these charged fibers are incorporated into fibrous webs, they provide unique properties, including improved filtering properties.

Abstract: The present invention is an improvement in electretized filtering means. This is an electric charge holding structure wherein the filter medium is covered on two opposite sides with an electrically conductive material having an air permeability that does not impair the air permeability of the filter and these two opposite sides are shorted together. This concept is similar to causing a short in the magnetic lines of force for the purpose of long time retention of the magnetic force as often employed in the vicinity of a permanent magnet. In this invention this idea is applied to electret as an air-filter medium.

Abstract: A method for forming a filter of electrically charged electret fiber material, consisting of a high molecular weight, nonpolar polymeric substance, comprising drawing, charging, and fibrillating a foil of said high molecular weight substance. The fibrillated foil is wound and then crimping is effected.

Abstract: In a process for the production of fibre filters, the fibre material is sprayed electrostatically from the liquid state and deposited as a fibre fleece on a conductive support. The starting materials used are solutions of high polymers in readily volatile solvents. The filters obtained have substantially improved properties.

Abstract: A method for forming a filter of electrically charged electret fiber material, consisting of a high molecular weight, nonpolar polymeric substance, comprising drawing, charging, and fibrillating a foil of said high molecular weight substance. The fibrillated foil is wound and then crimping is effected.