Provided is a filter material for an automatic transmission oil filter that has excellent filtration performance and that can trap even dust having a small particle size. The filter material comprises an entangled nonwoven fabric in which fine fibers generated from dividable composite fibers are entangled with each other.

A method for producing a coating film-forming composition for lithography, including a step for passing a liquid through a filter cartridge. The filter cartridge is obtained by layering more than one type of filtration base fabrics or winding same around a hollow inner tube, wherein: the fabrics are non-woven fabrics in which metal-adsorbing groups are chemically bonded to polyolefin fibers; the fabrics contain non-woven fabric layers A and B; layer A is configured from polyolefin fibers to which sulfonic acid groups are chemically bonded as metal-adsorbing groups; and layer B is configured from polyolefin fibers to which at least one type selected from among amino groups, N-methyl-D-glucamine groups, iminodiacetic acid groups, iminodiethanol groups, amidoxime groups, phosphoric acid groups, carboxylic acid groups and ethylenediamine triacetic acid groups chemically bonded as metal-adsorbing groups. Thus, the amount of metal impurities that are the cause of minute defects on a wafer can be reduced.

A tetrafluoroethylene polymer is provided in an air filter medium having a pressure loss that can be reduced and made uniform at a plurality of positions. The tetrafluoroethylene polymer may also be provided in an air filter medium, a filter pack, or an air filter unit. The tetrafluoroethylene polymer has drawability and non-melt processability. The tetrafluoroethylene polymer has a ratio S.sub.2/S.sub.1 of 0.60 or more, where S.sub.2 represents an endotherm mJ/mg in a range of T.sub.0° C. or higher and 350° C. or lower, T.sub.0° C. is a temperature 2.5° C. lower than a temperature T.sub.p° C. (340≤T.sub.p≤345) at which a minimum point is given on a heat-of-fusion curve obtained by measuring an unbaked polymer for measurement having no history of heating to a temperature of 300° C. or higher using a differential scanning calorimeter at a temperature-increasing rate of 2° C./min, and S.sub.1 represents an endotherm mJ/mg in a range of 320° C. or higher and T.sub.0° C. or lower.

Filter media comprising fibrillated fibers and glass fibers are generally described.

It is an object of the present invention to provide a nonwoven fabric having mechanical strength which is hardly cut and broken by an external force, and a separator for electrochemical devices using the nonwoven fabric.

The inventive nonwoven fabric has a sum of tensile strengths by zero-span per basis weight in the machine direction and the cross-machine direction of 6.5N/50 mm or more. Thus, the strength of the constituent fibers of this nonwoven fabric against an external force is high, and this nonwoven fabric has mechanical strength which is hardly cut and broken by an external force.

The separator for electrochemical devices of the present invention is composed of this nonwoven fabric.

Filter media, filter elements, and arrangements of filters, wherein at least one polymeric mesh adsorbent is comprising at least one functional polymer or derivative of a functional polymer, capable of binding contaminants from a gas mixture, preferably proteins, peptides, glycoproteins, lipoproteins, nucleic acids, carbohydrates, and lipids. These contaminants may exhibit allergenic or toxic properties. These contaminants are preferably embedded in aerosols or attached to small particles. Processes for the synthesis of a polymeric mesh, whereas at least one functional polymer is immobilized via generation of amide or ester bonds, whereas all reactants are not activated and not comprising active groups.

A nonwoven fabric is formed of fibers of 0.10 μm or more and 5.00 μm or less. The nonwoven fabric includes a coarse layer portion and a dense layer portion. In the coarse layer portion, a void volume Pc is at least 90% and an average pore diameter Dc is in a range of 0.5 μm or more and 50 μm or less. In the dense layer portion, a void volume Pd is at least 70% and a relative standard deviation of pore diameter distribution is 20% or less.

Articles and methods involving filter media are generally provided. In certain embodiments, the filter media includes at least a first layer, a second layer, and an adhesive resin positioned between the first layer and the second layer. In some embodiments, the first layer may be a pre-filter layer or a support layer. The second layer may, for example, comprise fibers formed by a solution spinning process and/or may comprise fine fibers. In some embodiments, the adhesive resin may be present in a relatively low amount and/or may have a low glass transition temperature. The filter media as a whole may have one or more advantageous properties, including one or more of a high stiffness, a high bond strength between the first layer and the second layer, a high gamma, and/or a low increase in air resistance after being subjected to an IPA vapor discharge. The filter media may be, for example, a HEPA filter and/or an ULPA filter.

This depth filter comprises a substrate layer, a filtration layer, and a skin layer in this order. The substrate layer and the skin layer are layers obtained by winding and thermally fusing a nonwoven cloth configured from fibers having an average fiber diameter of 150 μm or more. The filtration layer is a layer obtained by winding a layered body two or more times, the layered body containing at least a net and a nonwoven cloth included only in the filtration layer. The average fiber diameter of the nonwoven cloth constituting the substrate layer and the average fiber diameter of the nonwoven cloth constituting the skin layer are larger than the average fiber diameter of the nonwoven cloth included only in the filtration layer.

A filter medium of the present disclosure has a laminate structure composed of a first polytetrafluoroethylene (PTFE) porous membrane, a first air-permeable supporting member, a second PTFE porous membrane, and a second air-permeable supporting member laminated in this order. The first PTFE porous membrane constitutes an exposed surface of the filter medium. A ratio of a transmittance of the first PTFE porous membrane to a transmittance of the second PTFE porous membrane is 100 or more. The filter medium of the present disclosure is a filter medium which includes the PTFE porous membranes, from which dust deposited on a surface over a period of use can be easily removed, and which has excellent reusability demonstrated by reduction of a filtration performance decrease caused by removal of dust.