Filter material, method for producing the filter material, and use of melt-blown polypropylene fibers
AssigneeCarl Freudenberg KG
InventorsHeiko SCHACHT, Rosemarie KURZER, Jochen HERMANN, Oliver STAUDENMAYER
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Abstract
The disclosure relates to a filter material comprising a first layer, comprising melt-blown polypropylene fibers, wherein the polypropylene fibers have a fiber diameter in a range from 400 nm to 600 nm at a relative frequency, as determined by means of the method disclosed in the description, of at least 20%, and a fiber diameter in a range from >600 nm to 800 nm at a relative frequency, as determined by means of the method disclosed in the description, of at least 20%.
Claims20
A filter material comprising
- a first layer comprising melt-blown polypropylene fibers which have a fiber diameter in a range from 400 nm to 600 nm at a relative frequency of at least 20%, and a fiber diameter in a range from >600 nm to 800 nm at a relative frequency of at least 20%.
A method for producing a filter material, the method comprising the steps of:
- producing a polypropylene melt, wherein the polypropylene has a melt flow rate (MFR) of from 800 to 4000 g/10 min,
- adding at least one sterically hindered hydroxylamine ester, thereby obtaining a melt-blowing mixture having a content of the sterically hindered hydroxylamine ester in the melt-blowing mixture in a range from 0.1 to 5 wt. % relative to the total weight of the melt-blowing mixture,
- melt blowing the melt-blowing mixture while stretching under air having a temperature of at least 240° C., measured at the spinneret, giving melt-blown polypropylene fibers, wherein the polypropylene fibers have a fiber diameter in a range from 400 nm to 600 nm at a relative frequency of at least 20%, and a fiber diameter in a range from >600 nm to 800 nm at a relative frequency of at least 20%, and
- laying the spun polypropylene fibers on a first substrate, producing a polypropylene filter layer.
A method of using melt-blown polypropylene fibers, the method comprising manufacturing a filter material layer comprising a fiber diameter of less than 1 μm, wherein the polypropylene fibers have a fiber diameter in a range from 400 nm to 600 nm at a relative frequency of at least 20%, and a fiber diameter in a range from >600 nm to 800 nm at a relative frequency of at least 20%.
Dependencies are inferred from the claim text.