Abstract: The inventive semi-finished product for a filter, particularly an air filter, comprises a filter medium, wherein said filter medium comprises a nonwoven having fibrous structure produced in a melt-spinning process and at least partially arranged in pleated layers.

Abstract: A pleatable nonwoven material is provided, including thicker form-giving fibers and thinner fibers determining the filter effect, wherein the thinner fibers are incorporated largely homogeneously in the thicker fibers running in the direction along the surface of the nonwoven material and a distribution density gradient of the thinner fibers is established perpendicular to the surface of the nonwoven material such that the highest concentration of thinner fibers is in the region of the center or on one of the two outsides, wherein the thicker and thinner fibers are bonded together by solidification from the melted condition and are made from the same material.

Abstract: An air filter medium consisting of a non-woven is provided, which is produced using a melting and spinning method and has a depth filter constituent and a surface filter constituent, wherein the air filter medium is configured such that it has long-lasting functionality owing to the depth filter constituent and can be substantially regenerated with a reverse pulse owing to the surface filter constituent.

Abstract: The invention relates to a method for producing a nonwoven fabric (1), in particular a filter medium or air filler medium consisting of a nonwoven, in a melt-spinning method comprising the following steps: Melting a raw material, spraying the raw material from at least one spinning die (6) and capturing the raw material on a support layer (12) such that the nonwoven fabric (1) is formed. The support layer (12) has structures, so that spacers (2) are formed in the nonwoven fabric (1).

Abstract: A pleatable nonwoven material is provided, including thicker form-giving fibers and thinner fibers determining the filter effect, wherein the thinner fibers are incorporated largely homogeneously in the thicker fibers running in the direction along the surface of the nonwoven material and a distribution density gradient of the thinner fibers is established perpendicular to the surface of the nonwoven material such that the highest concentration of thinner fibers is in the region of the center or on one of the two outsides, wherein the thicker and thinner fibers are bonded together by solidification from the melted condition and are made from the same material.

Abstract: Air filter medium from a non-woven fabric, which is produced in a melt-spinning process and comprises a depth filter component and a surface filter component, the air filter medium being designed such as to have a long service life and the surface filter component allowing regeneration by way of a reverse pulse.

Abstract: A pleatable nonwoven material is provided, including thicker form-giving fibers and thinner fibers determining the filter effect, wherein the thinner fibers are incorporated largely homogeneously in the thicker fibers running in the direction along the surface of the nonwoven material and a distribution density gradient of the thinner fibers is established perpendicular to the surface of the nonwoven material such that the highest concentration of thinner fibers is in the region of the center or on one of the two outsides, wherein the thicker and thinner fibers are bonded together by solidification from the melted condition and are made from the same material.

Abstract: The invention relates to a filter arrangement including a pleated nonwoven layer for use as a motor vehicle interior filter. The nonwoven layer is in the form of a single-layer, self-supporting micro-spunbonded fabric, the weight per unit area thereof being between 70 g/m.sup.2 and 200 g/m.sup.2, preferably between 110 g/m.sup.2 and 150 g/m.sup.2, the thickness thereof being between 0.7 and 1.5 mm, and the fibre thickness being between 2 and 20 .mu.m with an average fibre thickness of 3 to 5 .mu.m.