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US 2008/0073294 A1Published application
Porous Web, Particularly for Filtration of Biological Fluids
AssigneeFresenius Hemocare Italia S.R.L.
InventorsLaura Zambianchi, Paolo Verri
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Abstract
A porous web for filtering fluids comprising a plurality of adjacent layers of fibre material having anisotropic properties, characterised in that the anisotropic directions of a given vectorial property of at least two adjacent layers differ one from the other by an angle greater than 0° and preferably of at least 8°. The disclosed porous web is useful particularly as a filter element for the filtration of biological fluids, such as blood and blood components.
Claims17
1:
- A porous web for filtering fluids comprising a plurality of adjacent layers of fibre material having anisotropic properties, characterised in that the anisotropic directions of a given vectorial property of at least two adjacent layers differ one from the other by an angle greater than 0° and preferably of at least 8°.
2:
- A porous web according to claim 1, wherein said anisotropic direction is the direction lying in the plane of the web along which said vectorial property has a maximum value.
3:
- A porous web according to claim 1, wherein said vectorial property is a tensile property of said layers.
4:
- A porous web according to claim 1, wherein said vectorial property is the elongation at break.
5:
- A porous web according to claim 1, wherein said anisotropic direction is the direction of the ODF vector of the layers.
6:
- A porous web according to claim 1, wherein the anisotropic directions of said at least two layers are staggered by an angle of from 8° to 90°.
7:
- A porous web according to claim 1, wherein the vectors representing the anisotropic direction of all the layers have the same magnitude.
8:
- A porous web according to claim 1, wherein the vectors representing the anisotropic direction of said at least two layers differ in their magnitude up to 50%.
9:
- A porous web according to claim 1, wherein said layers are melt-blown fibre webs.
10:
- A porous web according to claim 1, wherein said layers are made from a fibre forming material selected from polypropylene, polyethylenterephthalate and polybuthylenterephthalate.
11:
- A porous web according to claim 1, characterised in that it comprises a plurality of set of layers, each set comprising a plurality of layers, wherein the layers of each set are oriented in the multilayer porous web according to the same anisotropic direction and the anisotropic direction of at least two consecutive sets differ one from the other by an angle of at least 8°.
12:
- A porous web according to claim 11, comprising from 2 to 50 set of layers, each set comprising from 1 to 50 layers.
13:
- A porous web according to claim 11, wherein the anisotropic direction of a given set of layers is staggered from the anisotropic direction of the adjacent set of layers by an angle of 90°.
14:
- A porous web according to claim 1, characterised in that it comprises a plurality of layers, wherein the machine direction of each layer is staggered with respect to the machine direction of the preceding layer by an angle of from 8° to 90°.
15:
- A porous web according to claim 1, comprising m layers, wherein m is from 2 to 100 and wherein the anisotropic direction of each layer is staggered by an angle equal to 360°:
- m with respect to the anisotropic direction of the preceding layer.
16:
- A filter device for filtration of biological fluids, comprising a housing with inlet and outlet ports and at least a porous web according to claim 1.
17:
- A method for the ex-vivo filtration of biological fluids, particularly for the leukocyte depletion of blood or blood components, comprising feeding said biological fluids through a filter device according to claim 16.