High temperature treated media
A thermally bonded filtration media that can be used in high temperature conditions in the absence of any loss of fiber through thermal effects or mechanical impact on the fiber components is disclosed. The filter media can be manufactured and used in a filter unit or structure, can be placed in a stream of removable fluid, and can remove a particulate load from the mobile stream at an increased temperature range. The combination of bi-component fiber, other filter media fiber, and other filtration additives provides an improved filtration media having unique properties in high temperature, high performance applications.
1 . A filter media comprising fibers in a thermally bonded nonwoven web comprising a mixture of:
30 wt-% to 80 wt-% of bi-component fibers comprising a core with a structural polymer portion and shell with a thermoplastic binder polymer portion, wherein the structural polymer portion has a melting point of at least 240° C. and the binder polymer portion has a melting point of up to 180° C., wherein the bi-component fibers comprise 5 wt-% to 25 wt-% of a first bi-component fiber comprising a first shell polymer with a first melting point and 25 wt-% to 60 wt-% of a second bi-component fiber comprising a second shell polymer with a second melting point that is higher than the first melting point, and wherein the bi-component fibers have a diameter of about 5 to 25 μm; and
20 wt-% to 70 wt-% of staple fibers comprising polymeric monocomponent fibers and one or both of cellulosic fibers and cotton linter fibers,
wherein the nonwoven web has a solidity of 10% or less.
2 . The filter media of claim 1 , wherein the first shell polymer has a melting point of 115° C. or lower, and the second shell polymer has a melting point of 120° C. or greater.
3 . The filter media of claim 1 , wherein the staple fibers comprise polyester fibers, polyamide fibers, polypropylene fibers, co-polyether ester fibers, polyethylene terephthalate fibers, polybutylene terephthalate fibers, poly ether ketone ketone (PEKK) fibers, poly ether ether ketone (PEEK) fibers, liquid crystalline polymer (LCP) fibers, or a combination of two or more thereof.
4 . The filter media of claim 1 , wherein the staple fibers comprise 1 wt-% to 20 wt-% of polyester fibers and 10 wt-% to 50 wt-% of cotton linter by weight of the nonwoven web, the polyester fibers having a diameter of 7 to 15 μm and the cotton linter fiber having a diameter of 15 μm to 55 μm.
5 . The filter media of claim 1 further comprising 0.1 wt-% to about 10 wt-% secondary fibers by weight of the nonwoven web, the secondary fibers comprising cotton fibers, linen fibers, wool fibers, cellulosic fibers, proteinaceous fibers, rayon fibers, acrylic fibers, aramid fibers, nylon fibers, polyolefin fibers, polyester fibers, polyvinyl chloride fibers, polyvinyl alcohol fibers, graphite fibers, metal fibers, ceramic fibers, or a combination of two or more thereof.
6 . The filter media of claim 5 , wherein the secondary fibers have a diameter in a range of 0.1 μm to 50 μm.
7 . The filter media of claim 5 , wherein the secondary fibers comprise binder fibers.
8 . The filter media of claim 1 , wherein the filter media is free of glass fibers.
9 . The filter media of claim 1 further comprising a binder resin comprising vinyl acetate, vinyl chloride, polyvinyl alcohol, polyvinyl acetate, polyvinyl acetyl, acrylic, methacrylic, polyamide, polyethylene vinyl acetate copolymer, urea phenol, urea formaldehyde, melamine, epoxy, polyurethane, or a combination of two or more thereof.
10 . A filter comprising a plurality of layers, at least one of the layers comprising a thermally bonded nonwoven web comprising a mixture of:
30 wt-% to 80 wt-% of bi-component fibers comprising a core with a structural polymer portion and shell with a thermoplastic binder polymer portion, wherein the bi-component fibers comprise 5 wt-% to 25 wt-% of a first bi-component fiber comprising a first shell polymer with a first melting point and 25 wt-% to 60 wt-% of a second bi-component fiber comprising a second shell polymer with a second melting point that is higher than the first melting point, and wherein the structural polymer portion has a melting point of at least 240° C. and the binder polymer portion has a melting point of up to 180° C., wherein the bi-component fibers have a diameter of about 5 to 25 μm; and
20 wt-% to 70 wt-% of staple fibers comprising polymeric monocomponent fibers and one or both of cellulosic fibers and cotton linter fibers,
wherein the nonwoven web has a solidity of 10% or less.
11 . The filter of claim 10 , wherein the nonwoven web forms a stage in the filter, the stage having a calculated pore size of at least 10 μm and no greater than 60 μm.
12 . The filter of claim 10 , wherein the first shell polymer has a melting point of 115° C. or lower, and the second shell polymer has a melting point of 120° C. or greater.
13 . The filter of claim 10 , wherein the staple fibers comprise polyester fibers, polyamide fibers, polypropylene fibers, co-polyether ester fibers, polyethylene terephthalate fibers, polybutylene terephthalate fibers, poly ether ketone ketone (PEKK) fibers, poly ether ether ketone (PEEK) fibers, liquid crystalline polymer (LCP) fibers, or a combination of two or more thereof.
14 . The filter of claim 10 , wherein the staple fibers comprise 1 wt-% to 20 wt-% of polyester fibers and 10 wt-% to 50 wt-% of cotton linter by weight of the nonwoven web, the polyester fibers having a diameter of 7 to 15 μm and the cotton linter fiber having a diameter of 15 μm to 55 μm.
15 . The filter of claim 10 further comprising 0.1 wt-% to about 10 wt-% secondary fibers by weight of the nonwoven web, the secondary fibers comprising cotton fibers, linen fibers, wool fibers, cellulosic fibers, proteinaceous fibers, rayon fibers, acrylic fibers, aramid fibers, nylon fibers, polyolefin fibers, polyester fibers, polyvinyl chloride fibers, polyvinyl alcohol fibers, graphite fibers, metal fibers, ceramic fibers, or a combination of two or more thereof.
16 . The filter of claim 15 , wherein the secondary fibers have a diameter in a range of 0.1 μm to 50 μm.
17 . The filter of claim 15 , wherein the secondary fibers comprise binder fibers.
18 . The filter of claim 10 , wherein the filter is free of glass fibers.
19 . The filter of claim 10 further comprising a binder resin comprising vinyl acetate, vinyl chloride, polyvinyl alcohol, polyvinyl acetate, polyvinyl acetyl, acrylic, methacrylic, polyamide, polyethylene vinyl acetate copolymer, urea phenol, urea formaldehyde, melamine, epoxy, polyurethane, or a combination of two or more thereof.