FILTER MEDIUM COMPRISING A REINFORCED NON-WOVEN FABRIC

Abstract

The invention relates to a filter medium comprising a reinforced non-woven fabric, to a method for the production thereof, and to the use thereof.

Claims

1-16. (canceled)

17. A filter medium comprising: a reinforced non-woven fabric, wherein the non-woven fabric has at least one non-woven layer based on preoxidised polyacrylonitryl (PAN) and at least one reinforcement layer, wherein the at least one reinforcement layer has a first side and a second side, wherein the at least one reinforcement layer is covered from the first side and/or the second side by the at least one non-woven layer.

18. The filter medium according to claim 17, wherein the filter medium has a flat or round shape.

19. The filter medium according to claim 17, wherein the at least one reinforcement layer is a woven fabric, a scrim, a knitted fabric, a crocheted fabric, a meshwork or a grid.

20. The filter medium according to claim 19, wherein a material of the at least one reinforcement layer is selected from the group consisting of metal fibres, metal wires, preoxidised PAN fibres, partially carbonised PAN fibres or carbon fibres.

21. The filter medium according to claim 17, wherein the at least one non-woven layer based on preoxidised PAN and/or the at least one reinforcement layer based on preoxidised PAN is carbonised or partially carbonised.

22. The filter medium according to claim 17, wherein the reinforced non-woven fabric has at least two non-woven layers, wherein a first non-woven layer is arranged on the first side of the reinforcement layer and a second non-woven layer is arranged on the second side of the reinforcement layer.

23. The filter medium according to claim 17, wherein at least two non-woven layers are arranged on the first side of the reinforcement layer, wherein each of the non-woven layers arranged on the first side of the reinforcement layer has different material properties.

24. The filter medium according to claim 17, wherein at least one of the non-woven layers and/or at least one of the reinforcement layers has an active component.

25. The filter medium according to claim 17, wherein at least one of the non-woven layers comprises fibres having an average fibre diameter which is in a range from 200 nm to 35 μm.

26. The filter medium according to claim 17, wherein the reinforced non-woven fabric has at least one electrically conductive non-woven layer and/or at least one electrically conductive reinforcement layer, and is configured such that an electrical discharge and/or a heating of the filter is made possible by applied electric current.

27. The filter medium according to claim 17, wherein the reinforced non-woven fabric has a tear strength of at least 10 dN/5 cm, and/or an air permeability of at least 20 L/(dm.sup.2*min) and at most 1000 L/(dm.sup.2*min) at 200 Pa.

28. The filter medium according to claim 17, wherein the surface mass of the at least one non-woven layer is at least 50 g/m.sup.2 and at most 1000 g/m.sup.2 and/or the surface mass of the reinforcement layer is at least 25 g/m.sup.2 and at most 1000 g/m.sup.2.

29. The filter medium according to claim 17, wherein a coating is applied to at least one of the non-woven layers.

30. The use of a filter medium according to claim 17 for filtering gases, wherein the filter medium is suitable for filtering gases having a temperature of at least up to 260° C., and the filter medium is heat-resistant and non-flammable up to at least 260° C.

31. A method for the production of a filter medium according to claim 17, comprising the steps of: providing at least one non-woven layer based on preoxidised PAN and at least one reinforcement layer, wherein the at least one reinforcement layer has a first side and a second side, and solidifying the at least one non-woven layer based on preoxidised PAN with the at least one reinforcement layer, so that the at least one reinforcement layer is covered from at least one of the first side and/or the second side by the at least one non-woven layer.

32. The method for the production of a filter medium according to claim 31, wherein a step of temperature treating takes place before or after the step of solidifying, preferably after solidifying.

Description

[0050] The drawings show different embodiments of the reinforced non-woven fabric according to the invention:

[0051] FIG. 1 is a cross section of a reinforced non-woven fabric according to one embodiment,

[0052] FIG. 2 is a cross section of a reinforced non-woven fabric according to a further embodiment,

[0053] FIG. 3 is a cross section of a reinforced non-woven fabric according to yet another embodiment,

[0054] FIG. 4 is a cross section of a reinforced non-woven fabric according to yet another embodiment.

[0055] The individual drawings are discussed in greater detail below.

[0056] FIG. 1 is a cross section of a reinforced non-woven fabric according to one embodiment. The reinforced non-woven fabric (1) has at least one non-woven layer (12) based on preoxidised PAN and a reinforcement layer (20). The reinforcement layer (20) has a first side (22) and a second side (24), wherein the reinforcement layer (20) is covered from at least one of the first side (22) and the second side (24) by the at least one non-woven layer (12). The first side (22) is preferably arranged towards a flow direction of a substance to be filtered and the second side (24) is arranged away from the flow direction of the substance to be filtered.

[0057] FIG. 2 shows a further preferred embodiment of the reinforced non-woven fabric, in which the reinforcement layer (20) is covered from both the first side (22) and the second side (24) by the at least one non-woven layer (12).

[0058] According to one embodiment, the reinforced non-woven fabric can have at least two non-woven layers (12, 14), wherein a first non-woven layer (12) can be arranged on the first side (22) of the reinforcement layer (20) and a second non-woven layer (14) can be arranged on the second side (24) of the reinforcement layer (20), as shown in FIG. 3.

[0059] FIG. 4 shows a further embodiment of the reinforced non-woven fabric which has at least three non-woven layers (12, 14, 16), at least two non-woven layers (12, 16) being arranged on the first side (22). In this case, each of the non-woven layers (12, 16) arranged on the first side (22) can have different material properties. When the reinforced non-woven fabric is used as a filter, each of the non-woven layers (12, 16) arranged on the first side (22) can be suitable for filtering different components. The non-woven layers (12, 16) arranged on the first side (22) can advantageously each be suitable for filtering components above a specific size. This makes it possible to filter the substance to be filtered gradually according to the size of the components.

LIST OF REFERENCE SIGNS

[0060] 1 reinforced non-woven fabric

[0061] 12, 14, 16 non-woven layer based on preoxidised PAN

[0062] 20 reinforcement layer

[0063] 22 first side of the reinforcement layer

[0064] 24 second side of the reinforcement layer