Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D39/00—Filtering material for liquid or gaseous fluids
  • B01D39/14—Other self-supporting filtering material ; Other filtering material
  • B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
  • B01D39/1607—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous
  • B01D39/1623—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of synthetic origin
  • B01D39/163—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being fibrous of synthetic origin sintered or bonded
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D37/00—Processes of filtration
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D39/00—Filtering material for liquid or gaseous fluids
  • B01D39/08—Filter cloth, i.e. woven, knitted or interlaced material
  • B01D39/083—Filter cloth, i.e. woven, knitted or interlaced material of organic material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D39/00—Filtering material for liquid or gaseous fluids
  • B01D39/14—Other self-supporting filtering material ; Other filtering material
  • B01D39/16—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres
  • B01D39/18—Other self-supporting filtering material ; Other filtering material of organic material, e.g. synthetic fibres the material being cellulose or derivatives thereof
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/02—Types of fibres, filaments or particles, self-supporting or supported materials
  • B01D2239/0216—Bicomponent or multicomponent fibres
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/02—Types of fibres, filaments or particles, self-supporting or supported materials
  • B01D2239/0216—Bicomponent or multicomponent fibres
  • B01D2239/0233—Island-in-sea
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/02—Types of fibres, filaments or particles, self-supporting or supported materials
  • B01D2239/025—Types of fibres, filaments or particles, self-supporting or supported materials comprising nanofibres
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/04—Additives and treatments of the filtering material
  • B01D2239/0435—Electret
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
  • B01D2239/0604—Arrangement of the fibres in the filtering material
  • B01D2239/0618—Non-woven
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
  • B01D2239/0604—Arrangement of the fibres in the filtering material
  • B01D2239/0622—Melt-blown
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
  • B01D2239/0604—Arrangement of the fibres in the filtering material
  • B01D2239/0627—Spun-bonded
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
  • B01D2239/0604—Arrangement of the fibres in the filtering material
  • B01D2239/0636—Two or more types of fibres present in the filter material
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/06—Filter cloth, e.g. knitted, woven non-woven; self-supported material
  • B01D2239/065—More than one layer present in the filtering material
  • B01D2239/0654—Support layers
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/12—Special parameters characterising the filtering material
  • B01D2239/1216—Pore size
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/12—Special parameters characterising the filtering material
  • B01D2239/1225—Fibre length
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/12—Special parameters characterising the filtering material
  • B01D2239/1233—Fibre diameter
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/12—Special parameters characterising the filtering material
  • B01D2239/1258—Permeability
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/12—Special parameters characterising the filtering material
  • B01D2239/1266—Solidity
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01D—SEPARATION
  • B01D2239/00—Aspects relating to filtering material for liquid or gaseous fluids
  • B01D2239/12—Special parameters characterising the filtering material
  • B01D2239/1291—Other parameters

Definitions

• Filtration media such as the filtration media used for fuel filtration, often include glass microfibers. During certain types of filtration, however, there is a concern that glass microfibers may be released from the filtration media resulting in environmental contamination or, in the case of filtered fuel, resulting in damage to the internal combustion engine.
• This disclosure describes a filtration medium that is preferably substantially glass-free or glass-free.
• the filtration medium when the filtration medium is substantially glass-free or glass-free, the filtration medium preferably exhibits capacity and efficiency comparable to or better than similar glass-containing filtration media.
• this disclosure provides a nonwoven filtration medium including: 25 wt-% to 85 wt-% of a bicomponent fiber having a fiber diameter in a range of 5 microns to 25 microns and a fiber length of 0.1 cm to 15 cm; 5 wt-% to 50 wt% of a small efficiency fiber having a fiber diameter of at least 0.1 micron and less than 1 micron; 10 wt-% to 50 wt% of large efficiency fiber having a fiber diameter in a range of 1 micron to 5 microns; and 5 wt-% to 25 wt% of a microfibrillated fiber, wherein a majority of the microfibrillated fibers have a lateral dimension of up to 4 microns; wherein the nonwoven filtration medium is substantially free of glass fiber.
• the bicomponent fiber includes a structural polymer portion and a thermoplastic binder polymer portion, wherein the structural polymer portion has a melting point higher than the melting point of the binder polymer portion.
• the structural polymer portion of the bicomponent fiber has a melting point of at least 240°C and the binder polymer portion of the bicomponent fiber has a melting point in a range of 100°C to 190°C.
• the small efficiency fiber has a fiber diameter of at least 0.4 micron to less than 1 micron.
• the large efficiency fiber has a fiber diameter in a range of 2 microns to 4 microns.
• the small efficiency fiber includes PET or the large efficiency fiber includes PET; or both the small efficiency fiber and the large efficiency fiber include PET.
• the microfibrillated fibers comprise microfibrillated cellulose fibers.
• the nonwoven filtration medium has a solidity in a range of 5% to 15%. In some embodiments, the nonwoven filtration medium has a basis weight in a range of 24 g/m 2 to 100 g/m 2 . In some embodiments, the nonwoven filtration medium has a pore size in a range of 0.5 micron to 20 microns. In some embodiments, the nonwoven filtration medium has a P95/P50 ratio in a range of 1.5 to 3. In some embodiments, the nonwoven filtration medium has a thickness in a range of 0.12 mm to 1 mm. In some embodiments, the nonwoven filtration medium has a permeability in a range of 1 ft 3 /ft 2 /min at 0.5 inches of water to 100 ft 3 /ft 2 /min at 0.5 inches of water.
• the nonwoven filtration medium is substantially free of resin.
• the nonwoven filtration medium is free of glass fiber.
• this disclosure describes a method of filtering a liquid stream, the method including passing a liquid stream comprising a contaminant through a nonwoven filtration medium and removing the contaminant from the liquid stream.
• the liquid stream comprises fuel, hydraulic oil, process water, air, diesel engine fluid (DEF), diesel engine lube oil, or blow-by gas, or a combination thereof.
• DEF diesel engine fluid
• micron is equivalent to micrometer (pm).
• a “fiber” has an average fiber diameter of up to 100 micrometers.
• fibers have an aspect ratio (i.e., length to lateral dimension) of greater than 3:1, and preferably greater than 5:1.
• fiberglass typically has an aspect ratio of greater than 100:1.
• the “lateral dimension” is the width (in 2 dimensions) or diameter (in 3 dimensions) of a fiber.
• the term “diameter” refers either to the diameter of a circular cross-section of a fiber, or to a largest cross-sectional dimension of a non-circular cross-section of a fiber. Fiber lengths may be of finite lengths or infinite lengths, depending on the desired result.
• the “b ratio” or “b” is the ratio of upstream particles to downstream particles under steady flow conditions (ISO 16889:2008), as described in the Examples. The more efficient the filter, the higher the b ratio.
• the b ratio is defined as follows: b ⁇ where /Vd,u is the upstream particle count per unit fluid volume for particles of diameter d or greater and /Vd,D is the downstream particle count per unit fluid volume for particles of diameter d or greater. If present, a subscript attached to b (e.g., d) indicates the particle size for which the ratio is being reported.
• pore size for example P5, P50, and P95
• ratios of pore sizes for example, P95/P50
• Capillary flow porometry may be performed using a continuous pressure scan mode. It may be useful to use silicone oil, having a surface tension of 20.1 dynes/cm and a wetting contact angle of 0, as a wetting liquid.
• the sample may initially be tested dry, varying low pressure to high pressure, and then tested wet, again varying low pressure to high pressure. The test is typically performed at ambient temperature conditions (for example, 20°C to 25°C). 256 data points may be collected across the range of the scan of the pressures for both the dry curve and the wet curve. Typically, no tortuosity factor and/or a shape factor will be used (that is, for comparison to other test methods that use an adjustment factor, a factor equal to 1 may be used).
• a value P(x ) is the calculated pore size when the wet curve is equal to (100-x)% of the dry curve, as determined using the methodology described herein. Although a calculated value, this can be understood as representing the point at which x% of the overall flow through the layer passes through pores of that size or below.
• P50 the mean flow pore size
• P50 represents the point at which the wet curve is equal to half the dry curve, and may be viewed as the pore size such that 50% of the total flow through the layer is through pores of that size or below.
• pressure drop (also referred to herein as “dP” or “DR”) relates to the pressure (exerted by a pump) necessary to force fluid through the filter or filter medium (prior to the addition of a contaminant) for a particular fluid velocity. Unless otherwise indicated, pressure drop is clean pressure drop, measured as described in ISO 16889:2008. The sample may be tested using a test flow rate of 16 L/minute. The test may be performed to a terminal element differential pressure of 320 kPa.
• a filtration medium that is substantially free of glass may include less than 1 wt-% glass fiber.
• a filtration medium that is substantially free of resin may include less than 5 wt-% resin.
• a filtration medium that is substantially free of glass may include less than 1 wt-% glass fiber.
• a filtration medium that is substantially free of resin may include less than 5 wt-% resin.
• a “glass-free” filtration medium does not include any glass and a “resin-free” media does not include any resin.
• a,” “an,” “the,” and “at least one” are used interchangeably and mean one or more than one.
• a number for example, up to 50
• the number for example, 50
• the steps may be conducted in any feasible order. And, as appropriate, any combination of two or more steps may be conducted simultaneously.
• FIG. 1 shows a pictorial representation of a simulation of a glass-free filtration media including 14 pm-diameter bicomponent (Bico) fibers, 0.7 pm-diameter polyethylene terephthalate (PET) fibers, 2.5 pm-diameter PET fibers, and 1 pm-diameter microfibrillated rayon fibers, as further described in Example 1.
• the simulation of the rayon fibers does not depict the full extent of their bundle properties.
• FIG. 3 shows b4m measured for media prepared as described in Example 3.
• FIG. 4 shows b4m plotted against the fiber mass percentage of microfibrillated rayon and 700 nm PET in media with differing amounts of each fiber type, as further described in Example 4.
• FIG. 5A shows the P95/P50 plotted against the fiber mass percentage of microfibrillated rayon in media with differing amounts of microfibrillated rayon, as further described in Example 4.
• FIG. 5B shows the P95/P50 plotted against the fiber mass percentage of 2.7 pm-diameter PET fibers in media with differing amounts of 2.7 pm-diameter PET fibers, as further described in Example 4.
• FIG. 6A shows the Figure of Merit (FOM) plotted against the fiber mass percentage of microfibrillated rayon in media with differing amounts of microfibrillated rayon, as further described in Example 4.
• FIG. 5B shows FOM plotted against the fiber mass percentage of 0.7 pm - diameter PET fibers in media with differing amounts of 0.7 pm-diameter PET fibers, as further described in Example 4.
• FOM Figure of Merit
• This disclosure describes a filtration medium that is preferably substantially glass-free or glass-free.
• the filtration medium when the filtration medium is substantially glass-free or glass-free, the filtration medium preferably exhibits capacity and efficiency comparable to or better than similar glass-containing filtration media.
• this disclosure describes a filtration medium.
• the filtration medium is a non- woven filtration medium.
• the nonwoven filtration medium is substantially free of glass including, for example, a glass fiber. In some embodiments, the nonwoven filtration medium does not include glass.
• the nonwoven filtration medium includes: a bicomponent fiber; a “small efficiency fiber” wherein the “small efficiency fiber” as used herein is a fiber having a fiber diameter of at least 0.1 micron and less than 1 micron; a “large efficiency fiber” wherein a “large efficiency fiber” as used herein is a fiber having a fiber diameter in a range of 1 micron to 5 microns; and a microfibrillated fiber.
• small efficiency fiber or the large efficiency fiber or both preferably include polyethylene terephthalate (PET).
• PET polyethylene terephthalate
• the nonwoven filtration medium includes: 25 wt-% to 85 wt- % of a bicomponent fiber having a fiber diameter in a range of 5 microns to 25 microns and a fiber length in a range of 0.1 cm to 15 cm; 5 wt-% to 50 wt% of the small efficiency fiber; 10 wt-% to 50 wt% of the large efficiency fiber; and 5 wt-% to 25 wt% of a microfibrillated fiber, wherein a majority of the microfibrillated fibers have a lateral dimension of up to 4 microns.
• Example 2 One exemplary embodiment is shown in Example 2.
• Example 2 the inclusion of a fiber having a fiber diameter of at least 0.1 micron and less than 1 micron (700 nm) and a fiber having a fiber diameter in a range of 1 micron to 5 microns (2.5 pm) allowed for similar efficiencies (b) to be achieved while providing a more open structure that will prevent unwanted pressure drop. As shown in Example 3, these efficiencies can also be obtained without the use of a fiber having a fiber diameter of at least 0.1 micron and less than 1 micron (see FIG. 3), but such media is expected to be denser, resulting in an undesirable, higher pressure drop (dP).
• dP undesirable, higher pressure drop
• a nonwoven filtration medium that included only bicomponent fiber and a fiber having a fiber diameter of at least 0.1 micron and less than 1 micron would have very low strength, specifically the strength of the fiber matrix of the 0.1 micron to 1 micron fiber that form in the space between the larger bicomponent fibers, making it unsuitable for many uses, particularly those in which the filter media was subjected to dynamic forces.
• strength could be increased by including resin, using resin is undesirable because it fills pores in the media that could otherwise be used to collect contaminant and because it increases pressure drop.
• Example 4 including increasing amounts of a microfibrillated fiber and a fiber having a fiber diameter of at least 0.1 micron and less than 1 micron (700 nm) increases efficiency (see FIG. 4).
• Using increasing amounts of a microfibrillated fiber resulted in increased filter media performance, as indicated by Figure of Merit (FOM), a measure of the performance of a filter media and of the filter media’s ability to provide a certain level of clarification of a stream with a minimum energy used (FIG. 6A).
• FOM Figure of Merit
• using increased amounts of microfibrillated fibers increase the fiber entanglement and thus increased strength of the fiber matrix. Increased strength can also be gained by using materials that can form hydrogen bonds, such as rayon and cellulose.
• one or more of the fibers is selected or treated to alter the electrostatic charge of the media.
• the charge typically includes layers of positive or negative charges trapped at or near the surface of the polymer, or charge clouds stored in the bulk of the polymer.
• the charge may also include polarization charges which are frozen in alignment of the dipoles of the molecules.
• the filtration medium includes a bicomponent fiber. Any suitable bicomponent fiber may be used, and the bicomponent fiber may be selected depending on the intended use for the media.
• the filtration medium includes at least 25 wt-%, at least 30 wt-%, at least 35 wt-%, at least 40 wt-%, at least 45 wt-%, at least 50 wt-%, at least 55 wt-%, at least 60 wt- %, at least 65 wt-%, or at least 70 wt-% of the bicomponent fiber.
• the filtration medium includes up to 30%, up to 35 wt-%, up to 40 wt-%, up to 45 wt-%, up to 50 wt-%, up to 55 wt-%, up to 60 wt-%, up to 65 wt-%, up to 70 wt-%, up to 75 wt-%, or up to 85 wt-% of the bicomponent fiber.
• the filtration medium includes 25 wt-% to 85 wt-% of the bicomponent fiber.
• the filtration medium includes 25 wt-% to 75 wt-% of the bicomponent fiber.
• the filtration medium includes 25 wt-% to 70 wt-% of the bicomponent fiber.
• the filtration medium includes 50 wt-% of the bicomponent fiber.
• the bicomponent fiber has a fiber diameter of at least 1 micron, at least 5 microns, at least 10 microns, at least 15 microns, or at least 20 microns. In some embodiments, the bicomponent fiber has a fiber diameter of up to 5 microns, up to 10 microns, up to 15 microns, up to 20 microns, up to 25 microns, or up to 30 microns. In an exemplary embodiment, the bicomponent fiber has a fiber diameter in a range of 5 microns to 25 microns. In another exemplary embodiment, the bicomponent fiber has a fiber diameter of 14 microns.
• the bicomponent fiber has a fiber length of at least 0.1 cm, at least 0.5 cm, or at least 1 cm. In some embodiments, the bicomponent fiber has a fiber length of up to 0.5 cm, up to 1 cm, up to 5 cm, up to 10 cm, or up to 15 cm. In an exemplary embodiment, the bicomponent fiber has a fiber length in a range of 0.1 cm to 15 cm. In another exemplary embodiment, the bicomponent fiber has a fiber length of 6 mm.
• the bicomponent fiber includes a structural polymer portion and a thermoplastic binder polymer portion, the structural polymer portion having a melting point of higher than that of the binder polymer portion.
• the structural polymer portion and the binder polymer portion may be made out of any suitable materials.
• the structural polymer portion may include PET and the binder polymer portion may include copolymer PET (coPET).
• the structural polymer portion may include PET and the binder polymer portion may include Polyethylene (PE), PET, nylon, polypropylene (PP), polytetrafluoroethylene (PTFE), polyethersulfone (PES), polyphenylene sulfide (PPS), meta-aramids, or para-aramids.
• the binder polymer portion may include polyethylene (PE), poly lactic acid (PLA), nylon, ethylene vinyl alcohol (EVOH), polyvinyl chloride (PVC), polyvinylidene fluoride (PVDF) (for example, KYNAR), or any other polymer or modified polymer that is designed with a lower melting temperature than the core structure polymer.
• PE polyethylene
• PLA poly lactic acid
• EVOH ethylene vinyl alcohol
• PVDF polyvinylidene fluoride
• KYNAR polyvinylidene fluoride
• the structural polymer portion is the core and the thermoplastic binder polymer portion is the sheath of the bicomponent fiber.
• the structural polymer portion of the bicomponent fiber has a melting point of at least 240°C and the binder polymer portion of the bicomponent fiber has a melting point of up to 115°C.
• An exemplary bicomponent fiber 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 115°C is 271P, a 14 pm-diameter fiber available from Advansa (Hamm, Germany).
• the structural polymer portion of the bicomponent fiber has a melting point of at least 240°C and the binder polymer portion of the bicomponent fiber has a melting point in a range of 100°C to 190°C. In one exemplary embodiment, the structural polymer portion of the bicomponent fiber has a melting point of at least 240°C and the binder polymer portion of the bicomponent fiber has a melting point in a range of 120°C to 170°C. In another exemplary embodiment the structural polymer portion of the bicomponent fiber has a melting point of at least 240°C and the binder polymer portion of the bicomponent fiber has a melting point in a range of 140°C to 160°C.
• Exemplary bicomponent fibers wherein the structural polymer portion has a melting point of at least 240°C and the binder polymer portion has a melting point of in a range of 100°C to 190°C are TJ04CN (having a binder polymer portion melting point of 110°C), TJ04BN (having a binder polymer portion melting point of 150°C), both available from Teijin Fibers Limited of Osaka,
• the bicomponent fiber may include a first bicomponent fiber and a second bicomponent fiber.
• the bicomponent fiber may include a first bicomponent fiber wherein the structural portion has a melting point of at least 240°C and the binder polymer portion has a melting point of up to 115°C and a second bicomponent fiber wherein the structural polymer portion has a melting point of at least 240°C and the binder polymer portion has a melting point in a range of 100°C to 190°C.
• the bicomponent fiber may include both Advansa 27 IP and TJ04BN.
• the filtration medium includes a “small efficiency fiber” wherein the “small efficiency fiber” as used herein is a fiber having a fiber diameter of at least 0.1 micron and less than 1 micron.
• the small efficiency fiber is preferably a PET fiber. In some embodiments, the small efficiency fiber may consist essentially of PET. In some embodiments, the small efficiency fiber may consist of PET.
• the small efficiency fiber may include nylon, an acrylic, rayon, polypropylene, polyethylene, ethylene vinyl alcohol (EVOH), poly lactic acid (PLA), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), or other suitable meltable polymers.
• EVOH ethylene vinyl alcohol
• PLA poly lactic acid
• PVA polyvinyl alcohol
• PVC polyvinyl chloride
• PTFE polytetrafluoroethylene
• the filtration medium includes at least 5 wt-%, at least 10 wt-%, at least 15 wt-%, at least 20 wt-%, at least 25 wt-%, at least 30 wt-%, at least 35 wt-%, at least 40 wt- %, or at least 45 wt-% of the small efficiency fiber.
• the filtration medium includes up to 15 wt-%, up to 20 wt-%, up to 25 wt-%, up to 30 wt-%, up to 35 wt-%, up to 40 wt- %, up to 45 wt-%, up to 50 wt-%, or up to 55 wt-% of the small efficiency fiber.
• the filtration medium includes 5 wt-% to 50 wt-% of the small efficiency fiber.
• the filtration medium includes 10 wt-% to 50 wt-% of the small efficiency fiber.
• the filtration medium includes 10 wt-% to 40 wt-% of the small efficiency fiber.
• the filtration medium includes 10 wt-% to 25 wt-% of the small efficiency fiber.
• the small efficiency fiber has a fiber diameter of at least 0.1 micron, at least 0.2 micron, at least 0.3 micron, at least 0.4 micron, at least 0.5 micron, at least 0.6 micron, or at least 0.7 micron. In some embodiments, the small efficiency fiber has a fiber diameter of up to 0.7 micron, up to 0.8 micron, up to 0.9 micron, or less than 1 micron. For example, in an exemplary embodiment, the small efficiency fiber has a fiber diameter of at least 0.4 micron and less than 1 micron. In another exemplary embodiment, the small efficiency fiber has a fiber diameter in a range of 0.6 micron to 0.8 micron. In a further exemplary embodiment, the small efficiency fiber has a fiber diameter of 0.7 micron.
• the small efficiency fiber is a PET fiber having a fiber diameter of 0.7 micron.
• the small efficiency fiber has a length of at least 0.5 mm, at least 1 mm, or at least 1.5 mm. In some embodiments, the small efficiency fiber has a length of up to 10 mm, up to 11 mm, up to 12 mm, or up to 15 mm. In an exemplary embodiment, the small efficiency fiber has a length in a range of 1 mm to 15 mm. In a further exemplary embodiment, the small efficiency fiber has a length in a range of 1 mm to 12 mm.
• the PET of the small efficiency fiber when the small efficiency fiber includes PET, preferably has a melting point of at least 250°C, more preferably at least 275°C, even more preferably at least 290°C.
• the filtration medium further includes a “large efficiency fiber” wherein a “large efficiency fiber” as used herein is a fiber having a fiber diameter in a range of 1 micron to 5 microns.
• the large efficiency fiber is preferably a PET fiber. In some embodiments, the large efficiency fiber may consist essentially of PET. In some embodiments, the large efficiency fiber may consist of PET.
• the large efficiency fiber may include nylon, an acrylic, rayon, polypropylene, polyethylene, ethylene vinyl alcohol (EVOH), poly lactic acid (PLA), polyvinyl alcohol (PVA), polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), or other suitable meltable polymers.
• the filtration medium includes at least 10 wt-%, at least 15 wt-%, at least 20 wt-%, at least 25 wt-%, or at least 30 wt-% of the large efficiency fiber.
• the filtration medium includes up to 15 wt-%, up to 20 wt-%, up to 25 wt-%, up to 30 wt-%, up to 35 wt-% of the large efficiency fiber, up to 40 wt-% of the large efficiency fiber, up to 45 wt-% of the large efficiency fiber, or up to 50 wt-% of the large efficiency fiber.
• the filtration medium includes 10 wt-% to 50 wt-% of the large efficiency fiber.
• the filtration medium includes 10 wt-% to 40 wt-% of the large efficiency fiber.
• the filtration medium includes 10 wt-% to 25 wt-% of the large efficiency fiber.
• the large efficiency fiber has a fiber diameter of at least 1 micron, at least 1.5 microns, at least 2 microns, at least 3 microns, or at least 4 microns. In some embodiments, the large efficiency fiber has a fiber diameter of up to 1.5 microns, up to 2 microns, up to 3 microns, up to 4 microns, or up to 5 microns. For example, in an exemplary embodiment, the large efficiency fiber has a fiber diameter in a range of 2 microns to 4 microns. In another exemplary embodiment, the large efficiency fiber has a fiber diameter in a range of 2 microns to 3 microns. In yet another exemplary embodiment, the large efficiency fiber has a fiber diameter of 2.5 microns. In a further exemplary embodiment, the large efficiency fiber has a fiber diameter of 2.7 microns.
• the small efficiency fiber is a PET fiber having a fiber diameter of 2.7 microns.
• the large efficiency fiber has a length of at least 0.5 mm, at least 1 mm, or at least 1.5 mm. In some embodiments, the large efficiency fiber has a length of up to 10 mm, up to 11 mm, up to 12 mm, or up to 15 mm. In an exemplary embodiment, the large efficiency fiber has a length in a range of 1 mm to 15 mm. In a further exemplary embodiment, the large efficiency fiber has a length in a range of 1 mm to 12 mm.
• the PET of the large efficiency fiber when the large efficiency fiber includes PET, preferably has a melting point of at least 250°C, more preferably at least 275°C, even more preferably at least 290°C.
• the nonwoven filtration medium includes a microfibrillated fiber.
• a microfibrillated fiber is a fiber that has been processed to develop fibers with a higher surface area, branched structure than unprocessed fibers.
• the microfibrillated fiber may be a microfibrillated acrylic fiber, including, for example, fibrillated CFF fibers (available from Engineered Fiber Technology,
• the microfibrillated fiber may be a microfibrillated cellulose fiber including, for example, rayon such as Lyocell or TENCEL.
• the microfibrillated fiber may be a microfibrillated para-aramid fiber including, for example, TWARON Pulp (Teijin Aramid, B.V., The Netherlands).
• the microfibrillated fiber may be a microfibrillated liquid crystal polymer (LCP) fiber, including, for example, microfibrillated VECTRAN fibers (available from Engineered Fiber Technology, Shelton, CT).
• LCP microfibrillated liquid crystal polymer
• the microfibrillated fiber may be a microfibrillated poly-p-phenylene benzobisoxazole (PBO) fiber including, for example, fibrillated ZYLON fibers (available from Engineered Fiber Technology, Shelton, CT).
• PBO microfibrillated poly-p-phenylene benzobisoxazole
• the filtration medium includes at least 5 wt-%, at least 10 wt-%, at least 15 wt-%, at least 20 wt-%, at least 25 wt-%, or at least 30 wt-% of the microfibrillated fiber. In some embodiments, the filtration medium includes up to 15 wt-%, up to 20 wt-%, up to 25 wt-%, up to 30 wt-%, up to 35 wt-% of the microfibrillated fiber, or up to 40 wt-% of the microfibrillated fiber. In an exemplary embodiment, the filtration medium includes 5 wt-% to 40 wt-% of the microfibrillated fiber.
• the filtration medium includes 5 wt-% to 25 wt-% of the microfibrillated fiber. In a further exemplary embodiment, the filtration medium includes 10 wt-% to 40 wt-% of the microfibrillated fiber. In yet another exemplary embodiment, the filtration medium includes 10 wt-% to 25 wt-% of the microfibrillated fiber. In additional exemplary embodiments, the filtration medium includes 12.5 wt-% or 25 wt-% of the microfibrillated fiber.
• the microfibrillated fiber include a microfibrillated cellulose.
• microfibrillated cellulose herein refers to that material as defined by G. Chinga- Carrasco in Nanoscale Research Letters , 2011; 6:417: “MFC materials may be composed of (1) nanofibrils, (2) fibrillar fines, (3) fibre fragments and (4) fibres. This implies that MFC is not necessarily synonymous with microfibrils, nanofibrils or any other cellulose nano- structure. However, properly produced MFC materials contain nano-structures as a main component, i.e.
• microfibrillated cellulose does not include dry ground cellulose (also referred to as micronized cellulose or microfme cellulose) and does not include microcrystalline cellulose obtained by removing amorphous portions by acid hydrolysis, as described in U.S. Pat. No. 5,554,287.
• a majority (that is, greater than half) of the microfibrillated fibers have a lateral dimension (for example, a width in 2 dimensions) of up to 1 micron, up to 1.5 microns, up to 2 microns, up to 3 microns, or up to 4 microns. In some embodiments, a majority of the microfibrillated fibers have a lateral dimension of at least 0.5 micron, or at least 0.7 micron. In an exemplary embodiment, a majority of the microfibrillated fibers have a lateral dimension in a range of 0.5 micron to 4 microns.
• a majority of the microfibrillated fibers have a lateral dimension in a range of 0.5 micron to 1.5 microns. In a further exemplary embodiment, a majority of the microfibrillated fibers have a lateral dimension of up to 2 microns.
• the microfibrillated fibers are incorporated within (that is, distributed throughout) the fibrous media, thereby forming a filter media (also referred to herein as a “filtration medium” or “filter medium”).
• the nonwoven filtration medium has a solidity of at least 2%, at least 3%, at least 4%, at least 5%, at least 6%, at least 7%, at least 8%, at least 9%, or at least 10%. In some embodiments, the nonwoven filtration medium has a solidity of up to 5%, up to 6%, up to 7%, up to 8%, up to 9%, up to 10%, up to 11%, up to 12%, up to 13%, up to 14%, up to 15%, up to 16%, up to 17%, up to 18%, up to 19%, or up to 20%. In an exemplary embodiment, the nonwoven filtration medium has a solidity in a range of 5% to 15%. In some embodiments, solidity is preferably measured as described in the Examples.
• the nonwoven filtration medium has a basis weight of at least 20 grams per square meter (g/m 2 ), at least 24 g/m 2 , at least 25 g/m 2 , at least 30 g/m 2 , at least 35 g/m 2 , at least 40 g/m 2 , at least 50 g/m 2 , at least 60 g/m 2 , or at least 70 g/m 2 .
• the nonwoven filtration medium has a basis weight of up to 25 g/m 2 , up to 30 g/m 2 , up to 35 g/m 2 , up to 40 g/m 2 , up to 50 g/m 2 , up to 60 g/m 2 , up to 70 g/m 2 , up to 75 g/m 2 , up to 80 g/m 2 , up to 85 g/m 2 , up to 90 g/m 2 , up to 95 g/m 2 , up to 100 g/m 2 , or up to 105 g/m 2 .
• the nonwoven filtration medium has a basis weight in a range of 24 g/m 2 to 100 g/m 2 . In some embodiments, basis weight is preferably measured using ASTM D646-13.
• the nonwoven filtration medium has a pore size of at least 0.5 micron, at least 1 micron, at least 1.5 microns, at least 2 microns, at least 3 microns, at least 5 microns, or at least 10 microns. In some embodiments, the nonwoven filtration medium has a pore size of up to 5 microns, up to 10 microns, up to 15 microns, or up to 20 microns. In an exemplary embodiment, the nonwoven filtration medium has a pore size of 0.5 micron to 20 microns. In an exemplary embodiment, the nonwoven filtration medium has a pore size of 2 microns to 15 microns. Pore size, as used herein, refers to mean flow pore size, calculated as described in ASTM F316-03.
• the nonwoven filtration medium has a P95/P50 ratio of at least 1.5 or at least 2. In some embodiments, the nonwoven filtration medium has a P95/P50 ratio of up to 3.
• the nonwoven filtration medium has a thickness of at least 0.1 mm, at least 0.12 mm, at least 0.15 mm, or at least 0.2 mm. In some embodiments, the nonwoven filtration medium has a thickness of up to 0.2 mm, up to 0.4 mm, up to 0.5 mm, up to 0.7 mm, or up to 1 mm. In some embodiments, thickness of the filtration medium has is preferably measured according to the TAPPI T411 om-15 test method using a foot pressure of 1.5 psi.
• the nonwoven filtration medium has a permeability of at least 1 ft 3 /ft 2 /min at 0.5 inches of water, at least 5 ft 3 /ft 2 /min at 0.5 inches of water, or at least 10 ft 3 /ft 2 /min at 0.5 inches of water.
• the nonwoven filtration medium has a permeability of up to 10 ft 3 /ft 2 /min at 0.5 inches of water, up to 20 ft 3 /ft 2 /min at 0.5 inches of water, up to 50 ft 3 /ft 2 /min at 0.5 inches of water, up to 75 ft 3 /ft 2 /min at 0.5 inches of water, or up to 100 ft 3 /ft 2 /min at 0.5 inches of water.
• the nonwoven filtration medium has a permeability in a range of 1 ft 3 /ft 2 /min at 0.5 inches of water to 100 ft 3 /ft 2 /min at 0.5 inches of water.
• the nonwoven filtration medium has a permeability in a range of 10 ft 3 /ft 2 /min at 0.5 inches of water to 75 ft 3 /ft 2 /min at 0.5 inches of water.
• air permeability is preferably measured according to ASTM D737-18.
• the nonwoven filtration medium is substantially free of resin. In some embodiments, the nonwoven filtration medium does not include a resin.
• resin was often used to maintain spacing of the fibers in a filter media and to prevent instability of the media. However, resin blocks the pores in a filter medium, reducing filtration medium solidity and, therefore, life.
• microfibrillated fiber in combination with the large efficiency fibers is particularly beneficial to allowing the filtration medium to be substantially free of resin.
• the microfibrillated fiber are believed to provide more tensile strength, helping to maintain spacing of the fibers.
• the large efficiency fibers are believed to provide more uniform pore structures.
• a nonwoven filtration medium includes bicomponent fiber in a range of 25 wt-% to 85 wt-%. Using less than 25 wt-% bicomponent fiber is expected to result in a media with inadequate strength because the binder portion of the bicomponent fiber helps hold the media together during use. Using more than 85 wt-% bicomponent fiber would result in a media without enough of the other fibers to provide the desired efficiency and uniform structure.
• a nonwoven filtration medium includes a small efficiency fiber (having a fiber diameter of at least 0.1 micron and less than 1 micron) in an amount in a range of 5 wt-% to 50 wt-%.
• a small efficiency fiber having a fiber diameter of at least 0.1 micron and less than 1 micron.
• Using less than 5 wt-% of the small efficiency fibers often results in a media that did not provide the desired efficiency (for example a b ⁇ mhi greater than 10).
• Using more than 50 wt- % of the small efficiency fibers would increase pressure drop and often results in a weaker media because the fibers were not in contact with another fiber that would help hold them in the media.
• a nonwoven filtration medium includes a large efficiency fiber (having a fiber diameter in a range of 1 micron to 5 microns) in an amount in a range of 10 wt-% to 50 wt-%. Using less than 10 wt-% of the large efficiency fibers often results in a media that has irregular pore sizes. Using more than 50 wt-% of the large efficiency fibers often results in a media that does not include enough small efficiency fibers to attain the desired efficiency or enough bicomponent fiber to provide the needed strength during use.
• a nonwoven filtration medium includes a microfibrillated fiber in an amount in a range of 5 wt-% to 25 wt-%. Using less than 5 wt-% of the microfibrillated fiber often results in a media with insufficient strength during use and low efficiency. Using more than 25 wt- % of the microfibrillated fiber often results in irregular pore sizes (as indicated by a high P95/P50 ratio).
• the filtration medium described herein may be used in any method contemplated by a skilled artisan. In some embodiments, the filtration medium described herein are particularly well suited for filtering a liquid stream.
• Exemplary liquid streams may include, for example, fuel, hydraulic oil, process water, air, diesel engine fluid (DEF), diesel engine lube oil, blow-by gas, etc., and combinations thereof.
• DEF diesel engine fluid
• blow-by gas blow-by gas
• a method of filtering a liquid stream may include passing a liquid stream comprising a contaminant through a nonwoven filtration medium, and removing the contaminant from the liquid stream.
• Aspect l is a nonwoven filtration medium comprising: 25 wt-% to 85 wt-% of a bicomponent fiber having a fiber diameter in a range of 5 microns to 25 microns and a fiber length of 0.1 cm to 15 cm; 5 wt-% to 50 wt% of a small efficiency fiber having a fiber diameter of at least 0.1 micron and less than 1 micron; 10 wt-% to 50 wt% of a large efficiency fiber having a fiber diameter in a range of 1 micron to 5 microns; and 5 wt-% to 25 wt% of a microfibrillated fiber, wherein a majority of the microfibrillated fibers have a lateral dimension of up to 4 microns; wherein the nonwoven filtration medium is substantially free of glass fiber.
• Aspect 2 is the nonwoven filtration medium of Aspect 1 comprising: 25 wt-% to 75 wt-% of the bicomponent fiber; 10 wt-% to 50 wt% of the small efficiency fiber; 10 wt-% to 25 wt% of the large efficiency fiber; or 10 wt-% to 25 wt% of the microfibrillated fiber; or a combination thereof.
• Aspect 3 is the nonwoven filtration medium of Aspect 1 or Aspect 2, wherein the wt% is based on the total weight of the bicomponent fiber, the small efficiency fiber, the large efficiency fiber, and the microfibrillated cellulose fiber.
• Aspect 4 is the nonwoven filtration medium of any of Aspects 1 to 3, wherein the bicomponent fiber comprises a structural polymer portion and a thermoplastic binder polymer portion, wherein the structural polymer portion has a melting point higher than the melting points of the binder polymer portion.
• Aspect 5 is the nonwoven filtration medium of Aspect 4, wherein the structural polymer portion of the bicomponent fiber has a melting point of at least 240°C and the binder polymer portion of the bicomponent fiber has a melting point of up to 115°C.
• Aspect 6 is the nonwoven filtration medium of Aspect 4, wherein the structural polymer portion of the bicomponent fiber has a melting point of at least 240°C and the binder polymer portion of the bicomponent fiber has a melting point in a range of 100°C to 190°C.
• Aspect 7 is the nonwoven filtration medium of Aspect 6, wherein the binder polymer portion of the bicomponent fiber has a melting point in a range of 140°C to 160°C.
• Aspect 8 is the nonwoven filtration medium of any of Aspects 4 to 7, wherein the structural polymer portion is the core of the bicomponent fiber and the sheath is the thermoplastic binder polymer portion of the bicomponent fiber.
• Aspect 9 is the nonwoven filtration medium of any of Aspects 4 to 8, wherein the structural polymer portion comprises polyethylene terephthalate (PET) and the thermoplastic binder polymer portion comprises coPET.
• PET polyethylene terephthalate
• thermoplastic binder polymer portion comprises coPET.
• Aspect 10 is the nonwoven filtration medium of any of the previous Aspects, wherein the bicomponent fiber comprises a first bicomponent fiber and a second bicomponent fiber.
• Aspect 11 is the nonwoven filtration medium of any of the previous Aspects, wherein small efficiency fiber has a fiber diameter of at least 0.4 micron and less than 1 micron.
• Aspect 12 is the nonwoven filtration medium of any of the previous Aspects, wherein the small efficiency fiber has a fiber diameter in a range of 0.6 micron to 0.8 micron.
• Aspect 13 is the nonwoven filtration medium of any of the previous Aspects, wherein the small efficiency fiber has a fiber diameter of 0.7 micron.
• Aspect 14 is the nonwoven filtration medium of any of the previous Aspects, wherein the small efficiency fiber has a length in a range of 1 mm to 15 mm.
• Aspect 15 is the nonwoven filtration medium of any of the previous Aspects, wherein the small efficiency fiber comprises polyethylene terephthalate (PET).
• PET polyethylene terephthalate
• Aspect 16 is the nonwoven filtration medium of any of the previous Aspects, wherein the large efficiency fiber has a fiber diameter in a range of 2 microns to 4 microns.
• Aspect 17 is the nonwoven filtration medium of any of the previous Aspects, wherein the large efficiency fiber comprises polyethylene terephthalate (PET).
• PET polyethylene terephthalate
• Aspect 18 is the nonwoven filtration medium of any of the previous Aspects, wherein a majority of the microfibrillated fibers have a lateral dimension of up to 2 microns.
• Aspect 19 is the nonwoven filtration medium of any of the previous Aspects, wherein a majority of the microfibrillated fibers have a lateral dimension in a range of 0.5 micron to 1.5 microns.
• Aspect 20 is the nonwoven filtration medium of any of the previous Aspects, wherein the microfibrillated fibers comprise microfibrillated cellulose fibers.
• Aspect 21 is the nonwoven filtration medium of any of the previous Aspects, wherein the nonwoven filtration medium has a solidity in a range of 5% to 15%.
• Aspect 22 is the nonwoven filtration medium of any of the previous Aspects, wherein the nonwoven filtration medium has a basis weight in a range of 24 g/m 2 to 100 g/m 2 .
• Aspect 23 is the nonwoven filtration medium of any of the previous Aspects, wherein the nonwoven filtration medium has a pore size in a range of 0.5 micron to 20 microns.
• Aspect 24 is the nonwoven filtration medium of any of the previous Aspects, wherein the nonwoven filtration medium has a P95/P50 ratio of at least 1.5 or at least 2.
• Aspect 25 is the nonwoven filtration medium of any of the previous Aspects, wherein the nonwoven filtration medium has a P95/P50 ratio of up to 3.
• Aspect 26 is the nonwoven filtration medium of any of the previous Aspects, wherein the nonwoven filtration medium has a thickness in a range of 0.12 mm to 1 mm.
• Aspect 27 is the nonwoven filtration medium of any of the previous Aspects, wherein the nonwoven filtration medium has a permeability in a range of 1 ft 3 /ft 2 /min at 0.5 inches of water to 100 ft 3 /ft 2 /min at 0.5 inches of water.
• Aspect 28 is the nonwoven filtration medium of any of the previous Aspects, wherein the nonwoven filtration medium is substantially free of resin.
• Aspect 29 is the nonwoven filtration medium of any of the previous Aspects, wherein the nonwoven filtration medium is substantially free of glass fiber.
• Aspect 30 is the nonwoven filtration medium of any of the previous Aspects, wherein the small efficiency fiber comprises polyethylene terephthalate (PET), and wherein the PET of the small efficiency fiber has a melting point of at least 250°C, at least 275°C, or at least 290°C.
• PET polyethylene terephthalate
• Aspect 31 is the nonwoven filtration medium of any of the previous Aspects, wherein the large efficiency fiber comprises polyethylene terephthalate (PET), and wherein the PET of the large efficiency fiber has a melting point of at least 250°C, at least 275°C, or at least 290°C.
• Aspect 32 is a method of filtering a liquid stream, the method comprising passing a liquid stream comprising a contaminant through a nonwoven filtration medium, the nonwoven filtration medium comprising the nonwoven filtration medium of any of the previous Aspects, and removing the contaminant from the liquid stream.
• Aspect 33 is the method of Aspect 32, wherein the liquid stream comprises fuel, hydraulic oil, process water, air, diesel engine fluid (DEF), diesel engine lube oil, or blow-by gas, or a combination thereof.
• the liquid stream comprises fuel, hydraulic oil, process water, air, diesel engine fluid (DEF), diesel engine lube oil, or blow-by gas, or a combination thereof.
• DEF diesel engine fluid
• Handsheets were prepared by weighing out of the component fibers to target the basis weight required when formed in a 30 cm by 30 cm sheet.
• a FORMAX 12" x 12" Stainless Steel Sheet Mold (Catalog No. G-100, Adirondack Machine Corporation, Hudson Falls, NY) was used as the handsheet former and was prepared by placing a uniform nonwoven scrim layer with pores smaller than 100 pm at the bottom of the former (no removable forming wires were used). The former was then filled with cold tap water to almost full, but to allow room for an additional 1.5 L of water to be added. 1 mL of Tide HE laundry soap (Procter & Gamble, Cincinnati, OH) was added to the water in the handsheet former.
• Media was tested as described in ISO 16889:2008 (Hydraulic fluid power — Filters — Multi-pass method for evaluating filtration performance of a filter element).
• the media area was 0.0507 m 2 ; the test flow rate was 16 L/minute, and the test was performed to a terminal element differential pressure of 320 kPa.
• Figure of Merit is a measure of the performance of a filter media and of the filter media’s ability to provide a certain level of clarification of a stream with a minimum energy used.
• FOM in kPa 1 is calculated using the following formula:
• FOM -1h(1/b 4mih )/(DR/it ⁇ velocity) 1h(1/b mih ) is the natural logarithm of 1 divided by b4 mih.
• b4 mih unitless
• pressure drop (DR or dP) in kPa pressure drop (DR or dP) in kPa
• media velocity in (mm/sec) are determined as described in the Liquid Filtration Performance Testing section, above.
• Thickness was measured according to TAPPI T411 om-15, entitled “Thickness (caliper) of paper, paperboard, and combined board;” a foot pressure of 1.5 psi was used.
• Basis Weight was measured using TAPPI T410 om-08, with the mass of the dry media (fibers and scrim) being measured using a 30 cm x 30 cm sample on scrim.
• Basis Volume (BV BW/Z), that is, it is calculated by dividing the basis weight by the thickness.
• a sample at least 38 cm 2 was cut from a media to be tested.
• the sample was mounted on a TEXTEST® FX 3310 (obtained from Textest AG, Schwerzenbach, Switzerland). Permeability through the media was measured using air, wherein cubic feet of air per square feet of media per minute (ft 3 air/ft 2 media/min) or cubic meters of air per square meters of media per minute (m 3 air/m 2 media/min) was measured at a pressure drop of 0.5 inches (125 Pa) of water.
• Pore size measurement was performed by capillary flow porometry method using a continuous pressure scan on a Porometer 3G (Quanachrome Instruments, Boynton Beach, CA).
• This method used silicone oil, having a surface tension of 20.1 dynes/cm and a wetting contact angle of 0, and samples were tested in both wet and dry states (first dry, then wet). Samples 6 mm in diameter were subjected to a continuous pressure scan selected to measure the majority of the cumulative pore size distribution in a range of 2% to 98%.
• the sample was tested from low pressure to high pressure, while wet and dry.
• the air flow and sample pressure from the saturated part of the test is commonly called the wet curve.
• 256 data points were collected across the range of the scan of the pressures for both the dry curve and the wet curve. Data points were collected across the scan at a rate of approximately 17 data points per minute.
• the test was performed at ambient conditions (for example, 20°C to 25°C). No empirical tortuosity factor and/or a shape factor was applied to adjust the pore size diameter definition.
• the flow porometry test procedure collects a set of pressure (typically plotted on the x-axis) and air flow (typically plotted on the y-axis) data for the dry sample, and a set of pressure and air flow data for the saturated (wet) sample. These two sets of data are commonly called the dry curve and the wet curve. That is: Based on capillary theory, the pressure across the sample (DR) can be converted to pore diameter (d) using the Young-Laplace formula,
• the cumulative flow pore size distribution (Q) is defined as the ratio of the wet curve over the dry curve as a function of pore diameter.
• Cumulative distributions may be represented as an increasing cumulative distribution from 0 to 100%, or as a decreasing cumulative distribution from 100% to 0%.
• the pore sizes in this document are defined from the increasing cumulative flow pore size distribution.
• Examples include, but are not limited to, the following:
• P5 is the pore diameter that has an increasing cumulative flow pore distribution of 5%.
• P10 is the pore diameter that has an increasing cumulative flow pore distribution of 10%.
• P50 is the pore diameter that has an increasing cumulative flow pore distribution of 50%.
• P90 is the pore diameter that has an increasing cumulative flow pore distribution of 90%.
• P95 is the pore diameter that has an increasing cumulative flow pore distribution of 95%.
• the maximum pore size was determined by detecting the bubble point using the Porometer 3G (Quanachrome Instruments, Boynton Beach, CA), using the Auto Bubble Point (BP Auto Tolerance) method. According to this method, the bubble point is found after fluid begins passing through the sample, and three consecutive measurement increased by at least 1%. The bubble point is the value at the start of this sequence of three points.
• a glass-free filter media including 40 wt-% 14 pm-diameter bicomponent fibers, 20 wt-% 0.7 pm-diameter PET fibers, 20 wt-% 2.5 pm-diameter PET fibers, and 20 wt-% 1 pm-diameter microfibrillated rayon fibers was simulated using Geodict (Math2Market). A pictorial representation of the resulting media is shown in FIG. 1.
• Handsheets were prepared as described above by mixing 24 g/m 2 of 14 pm-diameter bicomponent fibers (Advansa 27 IP) with varying amounts of 700 nm-diameter PET fibers (TJ04BN, Teijin Fibers Limited, Osaka, Japan) (FIG. 2, blue data points, blue trendline) or by mixing 24 g/m 2 of 14 pm-diameter bicomponent fibers with varying amounts of 700 nm-diameter PET fibers, 1 pm-diameter microfibrillated rayon fibers (Lyocell), and 2.5 pm-diameter PET fibers (Teijin Fibers Limited, Osaka, Japan) (FIG.
• Example 3 b4m was measured using ISO Fine test dust at a concentration of 40 mg/L for Captimax 190 SC (Ahlstrom) (FIG. 3, “Base Layer”), and for a combination of polyester meltblown (FF40/240 PBT, Ahlstrom) and Captimax 190 SC (Ahlstrom) (FIG. 3, “Polyester Meltblown on Base Layer”).
• Handsheets were prepared in a wet laid process by mixing 50 wt-% 14 pm-diameter bicomponent fibers with 1 pm-diameter microfibrillated rayon fibers (Lyocell) and 2.7 pm-diameter PET fibers (TJ04BN, Teijin) (FIG. 3, “DCI Glass Free on Base Layer”); b4m was measured using ISO Fine test dust at a concentration of 40 mg/L. Results are shown in FIG. 3.
• variable efficiency was observed. Without wishing to be bound by theory, this likely due to a lack of uniform pore sizes. The presence of larger pores results in a decrease in the efficiency observed when larger particles are added until those large particles fill the larger pores at which time efficiency increases again.
• Handsheets were prepared as described above by mixing co-PET/PET bicomponent fibers (TJ04CN, Teijin Ltd., Tokyo, Japan), 2.7 pm-diameter PET fibers (Teijin Ltd., Tokyo, Japan), microfibrillated cellulose fibers (L-10-4, Engineered Fibers Technology. LLC, Shelton, CT), and 700 nm-diameter PET fibers (Teijin Ltd., Tokyo, Japan) in the proportions indicated in Table 2A.
• co-PET/PET bicomponent fibers TJ04CN, Teijin Ltd., Tokyo, Japan
• 2.7 pm-diameter PET fibers Teijin Ltd., Tokyo, Japan
• microfibrillated cellulose fibers L-10-4, Engineered Fibers Technology. LLC, Shelton, CT
• 700 nm-diameter PET fibers Teijin Ltd., Tokyo, Japan
• the efficiency (b4m ) was compared with the combined fiber mass percentage (wt-%) of the microfibrillated rayon and the 700 nm-diameter PET fibers in each handsheet (FIG. 5). These results indicate that increasing the combined fiber mass percentage of these two fibers increases the efficiency of the resulting filter media.
• the P95/P50 ratio of the resulting media was compared with the fiber mass percentage (wt- %) of the microfibrillated rayon in each handsheet (FIG. 5 A) or the fiber mass percentage (wt-%) of the 2.7 pm-diameter PET fibers in each handsheet (FIG. 5B).
• the Figure of Merit (FOM) of the resulting media was compared with the fiber mass percentage (wt-%) of the microfibrillated rayon in each handsheet (FIG. 6A) or the fiber mass percentage (wt-%) of the 2.7 pm-diameter PET fibers in each handsheet (FIG. 6B). While increasing the fiber mass percentage of the 2.7 pm-diameter PET fibers does not improve FOM (FIG. 6B) because improving efficiency results in higher pressure drop, increasing the fiber mass percentage of the microfibrillated rayon increased FOM (FIG. 6A), indicating that efficiency is improved without a corresponding increase in pressure drop.
• 1 L-10-4 is Lyocell Fiber, 10 mL CSF, 4 mm Starting Length, available from Engineered Fibers Technology. LLC (Shelton, CT)

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