SELF-SUPPORTING PLEATABLE FIBROUS WEB ESPECIALLY USEFUL AS OIL FILTER MEDIA AND OIL FILTER COMPRISING THE SAME
Fibrous filtration media for hot oil filtration includes a nonwoven fibrous web containing synthetic fibers and at least about 15 wt. %, based on total weight of the fibrous web, of a binder component selected from thermoset binder resins and/or binder fibers. The synthetic fibers of the fibrous web will contain from about 2 wt. % to about 65 wt. %, for example between about 10 wt. % to about 50 wt. %, based on total weight of fibers in the fibrous web, of thermoplastic synthetic microfibers having an average diameter of less than 5μιτι. The synthetic fibers are bonded together with the binder component to form the fibrous web which is capable of forming a self-supporting, pleated oil filter media which retains pleats upon contact with oil having a temperature in a range encountered in an internal combustion engine.
1 - 45 . (canceled)
46 . A fibrous filtration media for hot oil filtration which includes a glass-free nonwoven fibrous web comprising:
synthetic fibers; and
at least about 15 wt. % to about 30 wt. %, based on total weight of the fibrous web, of a binder component selected from the group consisting of a thermoset binder resin selected from the group consisting of phenolic resins, epoxy resins and melamine resins, wherein
the synthetic fibers comprise from about 10 wt. % to about 50 wt. %, based on total weight of fibers in the fibrous web, of thermoplastic synthetic microfibers having an average diameter of less than 5 μm and at least about 10 wt. % based on total weight of the fibrous web of cellulosic fibers, wherein
the synthetic fibers are bonded together with the binder component to form the fibrous web, and wherein
the fibrous web is capable of forming a self-supporting, pleated oil filter media which retains pleats upon contact with oil having a temperature in a range encountered in an internal combustion engine.
47 . The fibrous filtration media according to claim 46 , wherein the media has a mean flow pore size of 25 μm or less.
48 . The fibrous filtration media according to claim 46 , wherein the media has a hot oil burst strength of at least 20 psi when measured after 144 hours in hot oil at 140° C.
49 . The fibrous filtration media according to claim 46 , wherein the synthetic fibers comprise between about 15 wt. % to about 50 wt. % of lyocell staple fibers.
50 . The fibrous filtration media according to claim 46 , wherein the synthetic fibers comprise basic thermoplastic staple fibers having an average fiber diameter of greater than 5 μm.
51 . The fibrous filtration media according to claim 50 , wherein the thermoplastic microfibers are selected from the group consisting of polyester fibers, polyalkylene fibers, polyacrylonitriles fibers, polyamide fibers and mixtures thereof; and wherein the basic thermoplastic fibers are selected from the group consisting of polyethylene terephthalate (PET) fibers, polybutylene terephthalate (PBT) fibers, polyethylene (PE) fibers, polypropylene (PP) fibers, nylon-6 fibers, nylon 6,6 fibers, nylon-6,12 fibers, and combinations thereof.
52 . The fibrous filtration media according to claim 51 , wherein the basic thermoplastic fibers comprise either:
(i) PET fibers having average fiber diameters of between about 5.0 μm to about 15 μm and having staple fiber lengths of between about 5 mm to about 10 mm such as about 5 mm to about 6.5 mm, or
(ii) a mixture of PET staple fibers comprising (a) between about 5 wt. % to about 25 wt. % of PET staple fibers having an average fiber diameter of about 5.5 μm, (b) between about 2 wt. % to about 15 wt. % of PET staple fibers having an average fiber diameter of about 9.0 μm, and (c) between about 10 wt. % to about 40 wt. % of PET staple fibers having an average fiber diameter of about 12.4 μm, all weight percentages being based on the total fiber weight.
53 . The fibrous filtration media according to claim 46 , wherein the fibrous web has an average thickness of between about 0.6 mm to about 1.5 mm.
54 . The fibrous filtration media according to claim 46 , wherein the fibrous web has a basis weight of between 50 and 400 gsm, a permeability of between about 2 to about 600 cfm/sf and a hot oil burst strength of at least 20 psi after 144 hours in hot oil at a temperature of 140° C.
55 . The fibrous filtration media according to claim 46 , further comprising at least one additive selected from the group consisting of wet strength additives, optical brighteners, fiber retention agents, colorants, fuel-water separation aides, and flame or fire retardants.
56 . The fibrous filtration media of claim 46 , comprising longitudinally extending and latitudinally separated grooves.
57 . The fibrous filtration media of claim 46 , wherein the filtration media is pleated.
58 . An oil filter unit for an internal combustion engine comprising the fibrous filtration media according to claim 46 .
59 . A method of making the fibrous filtration media for oil in an internal combustion engine according to claim 46 comprising:
(a) forming a wet laid sheet from an aqueous fibrous slurry comprised of (i) synthetic fibers, wherein the synthetic fibers comprise from about 10 wt. % to about 50 wt. %, based on total weight of fibers in the sheet, of thermoplastic synthetic microfibers having an average diameter of less than 5 μm, and (ii) at least about 10 wt. % based on total weight of the fibrous web of cellulosic fibers; and
(b) adding about 15 wt. % to about 30 wt. % based on total weight of the fibrous web of a thermoset binder resin selected from the group consisting of phenolic resins, epoxy resins, and melamine-based resins to the wet laid sheet to bond the synthetic fibers one to another and form a fibrous web is capable of forming a self-supporting, pleated oil filter media which retains pleats upon contact with oil having a temperature in a range encountered in an internal combustion engine; and
(c) optionally forming longitudinally extending and latitudinally separated grooves in the fibrous web; and/or pleating the filtration web.
60 . A method of filtering oil circulating in an internal combustion engine which comprises passing the oil through the fibrous filtration media of claim 46 to thereby filter the oil.