Abstract: A process for producing an aromatic polyester by esterifying a dicarboxylic acid mainly composed of an aromatic dicarboxylic acid and a glycol mainly composed of ethylene glycol in the presence of 1 to 30 mmol %, based on the dicarboxylic acid, of a quaternary phosphonium sulfonate having ester-forming functional group(s), and then polycondensing the resulting product.

Abstract: Disclosed is an improved filter formed from a non-dielectric material which has been coated with a dielectric material and electret treated by, for example, DC corona discharge treatment. Also disclosed is a method for the formation of the filter.

Abstract: An electrostatic filter includes a fibrous component including a mixture of wool and synthetic fibers and a resinous component including a perfluoroalkyl acrylate copolymer resin and a p-tert-butylphenol formaldehyde resin, which resinous component is adhering to the fibrous component, both of the fibrous substrate component and the resinous component being in electrostatically charged conditions.

Abstract: There is provided a method for forming a nonwoven electret fiber filter with a nonwoven web of electret fibers needle-punched to an open scrim support. The scrim support material has individual discrete open areas with an average cross-sectional area as viewed from the plane of the filter media of at least 0.25 mm.sup.2, preferably 1.0 mm.sup.2, and a pressure drop across the scrim support, without the filter web, of less than 1.5 mm H.sub.2 O measured at 98.4 meters/min gaseous face velocity. The resulting filter has enhanced lifetimes, a low pressure drop and high filtration efficiencies.

Abstract: The surface of a web or film is modified to impart the material with improved properties including wettability, printability, adhesion and static reduction. Such surface modification is achieved with an electrode structure which causes a filamentary discharge to pass generally horizontally across a surface of the electrode structure. A substrate to be treated is then positioned adjacent to the surface of the electrode structure so that the filamentary discharge is caused to flow horizontally across the surface of the substrate, in turn modifying the surface of the substrate and achieving the desired improvement in properties.

Abstract: The invention concerns an apparatus for the manufacture of films, in particular thin or very thin films, with a rotating roller with which a plastically deformable film preferably supplied by a slot extruder is conveyed and stretched, wherein between the roller and a metal belt arranged parallel and at a short distance from the roller is applied a voltage by which the film supplied is applied to the roller. In order to develop this apparatus in such a way that manufacture of films, in particular thin or very thin films, is possible with increased productivity and film quality, with the invention it is proposed that the metal belt comprises a sharp longitudinal edge which is arranged closest to the roller and directed onto it.

Abstract: A method for post-treating a precursor nonwoven web including consolidating the web laterally, thereby reducing the maximum pore size measure of the web and improving the filtration efficiency of the web, and subjecting the consolidated web to an electrostatic field to further enhance filtration efficiency.

Abstract: An apparatus for adjusting the path that a web formed by striking a contoured surface baffle will take as it descends to a collection surface, in which the baffle is mounted on a pivot plate which will pivot and cause the web to leave the contoured surface baffle at the desired angle.

Abstract: There is provided a vacuum cleaner filter medium which is a nonwoven spunbond web of conjugate spunbond fibers. The web has a Frazier permeability of at least 250 CFM, an NaCI efficiency of at least 65 percent, a Gurley Stiffness of at least 20 mg, and a pressure drop of 0.5 or less mm H.sub.2 O. The conjugate fibers are made from polymers, more particularly polyolefins, still more particularly polypropylene and polyethylene in a side-by-side configuration. The filter medium is treated by a hot-air knife and through-air bonded during the production process. The medium is also electret treated. The medium has sufficient stiffness to be converted into a filter by conventional techniques. While this invention is directed mainly to air purification and filtration, other gasses may be filtered as well.

Abstract: A conductive ceramic composition is disclosed which consists essentially of alumina, chromia, and magnesia, and is suitable for use as target electrodes in electrostatic fiber charging applications. Ceramics are disclosed which have exhibit volume resistivities of 10.sup.12 ohm-cm or less at 20.degree. C., and have excellent electrical stability and superior mechanical properties; and an electrostatic charging apparatus is disclosed which employs a ceramic electronic conductor having a volume resistivity of from about 1.times.10.sup.7 to 5.times.10.sup.10 ohm-cm and a hardness of at least 5 GPa.

Abstract: An apparatus and method for causing the polymerized excess monomer to separate from a molded lens by increasing the surface energy of the flange area of one mold piece, causing the polymerized excess monomer to stick thereto. Specifically when manufactured under inert atmosphere conditions, a particular manifold is needed to supply an oxygen bearing gas, air, to the area to be treated while preventing the oxygen from contaminating the lens manufacturing area of the molds or diluting the nitrogen atmosphere of other lens process areas. It has been found that generation of the ionized oxygen by means of a corona treatment electrode sufficiently increases the adherence of the polymer to the mold piece so treated.