CN105828904B - Fibrillated Fibers for Liquid Filtration Media - Google Patents

Abstract

This application describes a fiber web for use as a filter media. In some embodiments, the fiber web comprises fibrillated fibers and optionally non-fibrillated fibers, as well as other optional components (e.g., binder resin). In some embodiments, the fiber web comprises a limited amount of glass fiber or does not contain glass fiber. The various characteristics and amounts of the fibrillated fibers are selected to impart desired properties, including mechanical and filtration properties (e.g., dust holding capacity and efficiency), and other benefits.

Description

Fibrillated Fibers for Liquid Filtration Media

technical field

Various aspects described herein relate generally to fiber webs comprising fibrillated fibers that can be used in filter media.

Background technique

Filter media can be used in a variety of applications to remove contaminants. Typically, filter media includes one or more fiber webs. The fiber web provides a porous structure that allows fluid (eg, fuel, lubricating oil, hydraulic fluid, air) to flow through the web. Contaminant particles contained within the fluid can be trapped on the fiber web. The characteristics of the fiber web (eg, fiber size, fiber composition, basis weight, etc.) affect mechanical properties (eg, elongation, strength, etc.) and filtration performance (eg, dust holding capacity, liquid filtration efficiency, etc.).

Certain filter media contain meshes containing glass fibers. While generally having desirable filtration properties, fiberglass webs can exhibit limited strength and brittle characteristics, which can lead to fiber shedding during handling, further processing (eg, pleating, cutting), installation, and use. The presence of glass fibers in filter media can also cause environmental concerns.

In some applications, it is desirable to limit the amount of glass fibers in the web, but still achieve a desired balance of properties including high filtration efficiency and/or high dust holding capacity for a given pressure drop.

Contents of the invention

Fiber webs comprising fibrillated fibers and which can be used in filter media are described herein.

In some embodiments, a range of filter media is provided. In one set of embodiments, the filter media comprises a wet-laid web comprising a plurality of synthetic fibers. The wet-laid web has a value of [mean flow pore size (μm)/(permeability (cfm/sf)) ^0.5 ] less than or equal to about 3.0. Additionally, the wet-laid web comprises from about 0% to about 10% by weight glass fibers. The filter medium has a weight per unit area greater than about 10 g/m ² and less than or equal to about 1000 g/m ² , and a thickness of about 0.1 mm to about 10.0 mm.

In another set of embodiments, the filter media comprises a fibrous web comprising a plurality of synthetic fibers. The fiber web has a [mean flow pore size (μm)/(permeability (cfm/sf)) ^0.5 ] value of less than about 3.0. In addition, the fiber web has a dust holding capacity of greater than or equal to about 80 g/m ² , wherein the dust holding capacity is at a base upstream gravimetric level of 25 mg/L using Multipass Filter Tests according to the ISO 16889/19438 procedure. level, BUGL), a face velocity of 0.06cm/sec and a terminal pressure of 100kPa. The wet-laid web contains from about 0% to about 10% by weight glass fibers. In addition, the filter media has a weight per unit area of greater than about 10 g/m ² and less than or equal to about 1000 g/m ² , and a thickness of about 0.1 mm to about 10.0 mm.

In another set of embodiments, the filter media comprises a fiber web comprising a plurality of fibrillated fibers. The fiber web comprises from about 0% to about 10% by weight glass fibers. The filter media has a liquid filtration efficiency of at least 98% for particles of 4 microns or larger, wherein said efficiency uses a multi-pass filtration test according to the ISO 16889/19438 procedure at 25 mg/L Basal Upstream Gravity Level (BUGL), 0.06 cm/sec Face velocity and 100kPa terminal pressure are measured. In addition, the filter medium has a weight per unit area greater than about 10 g/m ² and less than or equal to about 1000 g/m ² , and a thickness of about 0.1 mm to about 10.0 mm.

In another set of embodiments, the filter media comprises a first layer comprising a plurality of organic polymer fibers, and a second layer comprising greater than or equal to 60% by weight fibrillated fibers. The first basis weight of the first layer is greater than or equal to about 10 g/m ² and less than about 300 g/m ² . The second basis weight of the second layer is greater than or equal to 3 g/m ² and less than about 200 g/m ² . The ratio of the first weight per unit area to the second weight per unit area is at least 3:1 and less than 14:1. The filter media has a thickness of about 0.3 mm to about 10.0 mm.

In another set of embodiments, the filter media comprises a first layer and a second layer combined with an additional layer (eg, a third layer). The first layer and/or the second layer is a wet-laid layer (eg, a layer formed by a wet-laying process). The additional layer is a non-wet-laid layer (e.g., a layer formed by a non-wet-laid process) and may comprise meltblown fibers, melt-spun fibers, spin-spun fibers, or fibers formed by other non-wet-laid processes . The first layer includes a plurality of organic polymer fibers and the second layer includes a plurality of synthetic fibers. At least one of the first layer and the second layer comprises fibrillated fibers (eg, from about 1% to about 100% by weight of the first layer and/or the second layer). The first layer and/or the second layer comprise from about 0% to about 10% by weight glass fibers. The additional layer contains synthetic polymer fibers. The filter media can achieve a fuel-water separation efficiency of at least about 30% (eg, about 60% to about 99.9%).

In certain embodiments described above and herein, the first layer and/or the second layer may be a non-wet-laid layer (e.g., made of melt-blown fibers, melt-spun fibers, dry-laid (carded) fibers, centrifugally spun fibers, spunbond fibers, and/or airlaid fibers), as described herein.

In certain embodiments above and described herein, the additional layer may have a basis weight of about 5 g/ ^m2 to about 800 g/ ^m2 , an air permeability of less than about 1300 cfm/sf, and an average fiber diameter of less than 100 microns.

In certain embodiments described above and herein, the entire filter media can have a basis weight of greater than about 10 g/ ^m2 and less than or equal to about 1000 g/ ^m2 , and can have a thickness of about 0.1 mm to about 10.0 mm.

In some embodiments described above and herein, the filter media can achieve an efficiency of at least 99% at 4 microns, an initial efficiency of at least 99%, and a dust holding capacity of at least 150 gsm.

Other advantages and novel features of the invention will become apparent from the following detailed description of the various non-limiting embodiments of the invention when considered in conjunction with the accompanying drawings. In the event that this specification and a document incorporated by reference contain conflicting and/or inconsistent disclosures, this specification shall control. If two or more documents incorporated by reference contain conflicting and/or inconsistent disclosures relative to each other, the document with the later effective date shall control.

Description of drawings

Non-limiting embodiments of the invention will be described by way of example with reference to the accompanying drawings, which are schematic and not drawn to scale. In the figures, each identical or nearly identical component that is shown is generally represented by a single reference numeral. For purposes of clarity, not every component is labeled, nor is every component in every embodiment of the invention shown where illustration is not required to enable those of ordinary skill in the art to understand the invention. In the attached picture:

Figure 1 is a schematic diagram illustrating a fiber web according to one set of embodiments.

Detailed ways

Fiber webs for filter media are described herein. In some embodiments, the fiber web comprises fibrillated fibers and optionally non-fibrillated fibers, and other optional components (eg, binder resin). In some embodiments, the fiber web contains limited or no glass fibers. The individual characteristics and amounts of the fibrillated fibers are selected to impart desired properties including mechanical and filtration properties (eg, dust holding capacity and efficiency), among other benefits. Filter media formed from mesh may be particularly useful in applications involving filtering fuel, but the media may also be used in other applications (eg, for filtering lubricating oil, hydraulic fluid, air). In some embodiments, the webs described herein may comprise multiple layers, although other configurations are possible.

Advantageously, in some embodiments, the use of fibrillated fibers can increase the surface area of the web, resulting in improved one or more properties of the media, such as increased particle capture efficiency and/or dust holding capacity. The use of fibrillated fibers can also result in a reduction in the average pore size of the web compared to a web having similar properties (eg, basis weight, fiber type, etc.) but lacking fibrillated fibers. Accordingly, webs comprising such fibrillated fibers may have relatively low pressure drop while achieving increased efficiency per unit thickness. In some embodiments, the fiber webs described herein can achieve these improved properties with limited or no glass fibers.

The webs described herein can have a single layer or multiple layers. In some embodiments comprising multiple layers, sharp layer boundaries may not always be apparent, as described in more detail below. An example of a fiber web is shown in FIG. 1 . As illustratively shown in FIG. 1 , web 10 includes first layer 15 and second layer 20 having a combined thickness 25 . Optionally, the web may contain additional layers (not shown). The first layer may be positioned upstream or downstream of the second layer in the filter element. In some embodiments, the first layer is a relatively open layer (e.g., has a relatively high air permeability) compared to the second layer, and the second layer is a relatively tight layer (e.g., has a relatively high air permeability) compared to the first layer. have a relatively low air permeability). In other embodiments, the first layer is a relatively dense layer compared to the first layer, and the second layer is a relatively open layer compared to the second layer.

As described in more detail below, one or more fibrillated fibers may be present in at least one layer of the web, for example in the first layer, in the second layer, in both the first layer and the second layer in, or in all layers. In some embodiments, the first layer can be configured to have a higher dust holding capacity. In some cases, the first layer may also be configured to have a higher filtration efficiency. In some embodiments, the first layer may comprise fibrillated fibers, but in other embodiments the first layer does not comprise fibrillated fibers. In some cases, the first layer may be positioned upstream of the second layer in the filter element. In some embodiments, the second layer comprises one or more fibrillated fibers and is configured to achieve higher filtration efficiency. In some embodiments, the second layer may also have good dust holding properties. The second layer may be arranged downstream of the first layer in the filter element. As described in more detail below, the properties of a fiber web can be modified by varying the amount of fibrillated fibers present in one or more layers of the fiber web, the type of fibrillated fibers, and/or the level of fibrillation of the fibers. Adjustment. Examples of suitable types, amounts and levels of fibrillation of fibrillated fibers in the various layers are provided below.

It should be understood that while FIG. 1 shows only first and second layers, other layers may be present in other embodiments. For example, the web may comprise a third layer disposed: directly adjacent to the first layer (e.g., on the opposite side from the second layer), directly adjacent to the second layer (e.g., on the opposite side from the first layer) side), or between the first and second floors. Additional layers are also possible. In certain embodiments, additional layers (e.g., third layer, fourth layer, etc.) may be used in the web to increase dust holding capacity, longevity, liquid filtration efficiency, water separation efficiency, and/or strength (e.g., Lun (Mullen's burst strength, tensile strength, elongation), as described in more detail below. Furthermore, it should be understood that any additional layer (eg, third layer, fourth layer, etc.) may have any of the characteristics or properties described herein for the first or second layer.

In some embodiments, web 10 includes a sharp demarcation between the first layer and the second layer. For example, the web may include a distinct interface 40 between two layers. In some such embodiments, the first and second layers may be formed separately and then combined by any suitable method (eg, lamination, collation) or through the use of an adhesive. The first and second layers (and any additional layers) can be formed using different processes or the same process. For example, each of the first and second layers (and any additional layers) can be formed by a wet-laid process, a non-wet-laid process (e.g., a dry-laid process, a spinning process, a melt-blown process) ) or any other suitable process independently formed.

In other embodiments, the web 10 does not include a sharp boundary between the first layer and the second layer. For example, a clear interface between two layers may not be apparent. In some cases, the layers forming the web may be indistinguishable from one another throughout the thickness of the web. In such embodiments, the first layer and the second layer may be formed by the same process (e.g., wet-laid process, non-wet-laid process (e.g., dry-laid process, spinning process, meltblown process) or any other suitable process) or formed by a different process. In some cases, the first layer and the second layer can be formed simultaneously.

Whether or not a clear boundary exists between the first and second layers, in some embodiments, the web 10 includes a gradient (i.e., a variation) of one or more of the following properties across some or all of the thickness of the web. ): e.g. amount of fibrillated fibers, fibrillation level of fibers, fiber diameter, fiber type, fiber composition, fiber length, fiber surface chemistry, pore size, material density, weight per unit area, hardness, composition (e.g., viscose ratio of binder, resin, crosslinker), stiffness, tensile strength, wicking ability, hydrophilicity/hydrophobicity, and conductivity). Webs suitable for use as filter media can optionally include a gradient of one or more performance characteristics across the thickness of the web, such as efficiency, dust holding capacity, pressure drop, permeability, and porosity. A gradient of one or more such properties may exist in the web between the top surface 30 and the bottom surface 35 of the web.

There can be different types and different configurations of gradients within the web. In some embodiments, the gradient of one or more properties between the top and bottom surfaces of the web is gradual (eg, linear, curvilinear). For example, the amount of fibrillated fibers of the web can increase from the top surface to the bottom surface of the web. In another embodiment, the web can include a stepped gradient of one or more properties across the thickness of the web. In one such embodiment, the property transition may occur primarily at the interface 40 between the two layers. For example, a fiber web (eg, having a first layer comprising a first fiber type and a second layer comprising a second fiber type) may have an abrupt transition between fiber types across the interface. In other words, the layers of the web can be relatively different. Other gradient types are also possible.

In certain embodiments, a web may include a gradient of one or more properties throughout a portion of the thickness of the web. In portions of the web where no property gradient exists, the properties may be substantially constant throughout that portion of the web. As described herein, in some cases, property gradients involve differences in components (e.g., types of fibers (e.g., fibrillated fibers, hardwood fibers, softwood fibers), additives, binders) across the thickness of the web. Proportion. In some embodiments, components may be present in different amounts or concentrations than in another portion of the web. In other embodiments, the component is present in one portion of the web but not in another portion of the web. Other configurations are also possible.

In some embodiments, a web has a gradient of one or more properties in two or more regions of the web. For example, a web comprising three layers may have a first gradient of one property across the first and second layers, and a second gradient of another property across the second and third layers. The first gradient and the second gradient may be the same in some embodiments, or different in other embodiments (eg, characterized by gradual and abrupt changes in thickness characteristics across the web). Other configurations are also possible.

The fiber web can comprise any suitable number of layers, eg, at least 2, 3, 4, 5, 6, 7, 8, or 9 layers, depending on the particular application and desired performance characteristics. It should be understood that, in some embodiments, the layers forming the web may not differ from one another across the thickness of the web. Thus, in some cases, a web formed from, for example, two "layers" or two "fibrous blends" may also be characterized by a single "layer" (or "composite" layer) having a gradient of properties across the web. . Such composite layers may optionally be combined with additional layers in the web to form, for example, gradients of one or more properties in some parts of the web but not one or more properties in other parts of the web. Gradient web.

For example, in one set of embodiments, the first layer of the web 10 of FIG. 1 does not include a gradient of properties across the thickness of the first layer, but the second layer includes a gradient of properties across the thickness of the second layer. In another example, the first layer of the web 10 of FIG. 1 includes a gradient of properties across the thickness of the first layer, but the second layer does not include a gradient of properties across the thickness of the second layer. In other embodiments, both the first layer and the second layer include one or more gradients of properties across the thickness of the layers. Other configurations are also possible. As described herein, the one or more properties that vary across the thickness of the layer may include, for example, the concentration of fibrillated fibers, the level of fibrillation of the fibers, the type of fibers (e.g., the type of fibrillated fibers), the Diameter, fiber composition, fiber length, fiber surface chemistry, pore size, material density, weight per unit area, hardness, proportion of components (e.g., binder, resin, crosslinker), stiffness, tensile strength, wicking capacity , hydrophilicity/hydrophobicity and conductivity.

As noted above, the fiber webs described herein comprise one or more fibrillated fibers. As is well known to those of ordinary skill in the art, fibrillated fibers comprise parent fibers that branch into smaller diameter fibrils, which in some cases may further branch into smaller diameter fibrils, The smaller diameter fibrils can also branch further. The branched nature of the fibrils creates a fiber web with high surface area and can increase the number of contact points between the fibrillated fibers and other fibers in the web. Such an increase in the points of contact of the fibrillated fibers of the web with other fibers and/or components can help to enhance the mechanical properties (eg, flexibility, strength) and/or filtration performance characteristics of the web.

In general, the fibrillated fibers included in the fiber web can have any suitable level of fibrillation. The level of fibrillation relates to the degree of branching in the fibers. The average fibrillation level of the fibers can vary between different layers in the plurality of layered webs. For example, the first layer may comprise fibers having a lower level of fibrillation than the fibers of the second layer. In other embodiments, the first layer may comprise fibers having a higher level of fibrillation than the fibers of the second layer.

The average fibrillation level may vary within a layer (or throughout the web) depending on whether the layer (or web) contains a single type of fibrillated fiber or more than one type of fibrillated fiber. Fibers of the same fiber type but fibrillated to different degrees may also be used in one or more layers of the web.

The level of fibrillation can be measured according to any number of suitable methods. For example, the level of fibrillation of fibrillated fibers can be measured according to the Canadian Standard Freeness (CSF) test specified by TAPPI Test Method T 227om 09 Pulp Freeness. This test can provide an average CSF value. In some embodiments, the average CSF value of the fibrillated fibers used in the web can vary from about 10 mL to about 750 mL. In certain embodiments, the average CSF value of the fibrillated fibers used in the web can be greater than or equal to 1 mL, greater than or equal to about 10 mL, greater than or equal to about 20 mL, greater than or equal to about 35 mL, greater than or equal to about 45 mL , greater than or equal to about 50 mL, greater than or equal to about 65 mL, greater than or equal to about 70 mL, greater than or equal to about 75 mL, greater than or equal to about 80 mL, greater than or equal to about 100 mL, greater than or equal to about 150 mL, greater than or equal to about 175 mL, greater than or about 200 mL or more, about 250 mL or more, about 300 mL or more, about 350 mL or more, about 500 mL or more, about 600 mL or more, about 650 mL or more, about 700 mL or more, or about 700 mL or more Equal to about 750mL.

In some embodiments, the fibrillated fibers used in the web may have an average CSF value of about 800 mL or less, about 750 mL or less, about 700 mL or less, about 650 mL or less, about 600 mL or less , less than or equal to about 550 mL, less than or equal to about 500 mL, less than or equal to about 450 mL, less than or equal to about 400 mL, less than or equal to about 350 mL, less than or equal to about 300 mL, less than or equal to about 250 mL, less than or equal to about 225 mL, less than or about 200 mL or less, about 150 mL or less, about 100 mL or less, about 90 mL or less, about 85 mL or less, about 70 mL or less, about 50 mL or less, about 40 mL or less, or about 40 mL or less Equal to about 25mL. Combinations of the above ranges are also possible (eg, an average CSF value of fibrillated fibers greater than or equal to about 10 mL and less than or equal to about 300 mL). Other ranges are also possible. The average CSF value of the fibrillated fibers used in the fiber web can be based on one type of fibrillated fiber or more than one type of fibrillated fiber.

In some embodiments, the level of fibrillation of fibrillated fibers can be measured according to the Schober Riegler (SR) test. In some embodiments, the average SR value of the fibrillated fibers may be greater than about 20° SR, greater than about 30° SR, greater than about 40° SR, greater than about 50° SR, or greater than about 60° SR. In some embodiments, the fibrillated fibers may have an average SR value of less than about 80° SR, less than about 70° SR, less than about 60° SR, less than about 50° SR, or less than about 40° SR. It will be appreciated that the average SR value may be between any of the above lower and upper limits. For example, the average SR value of the fibrillated fibers can be from about 20°SR to about 70°SR, from about 20°SR to about 60°SR, or from about 30°SR to about 50°SR, from about 32°SR to about 52°SR. °SR, or about 40°SR to about 50°SR.

It should be understood that in certain embodiments, the fibers may have a level of fibrillation outside the above ranges.

In embodiments where the web comprises at least a first layer and a second layer, such as the embodiment shown illustratively in Figure 1, the average CSF value of the fibrillated fibers (if present) in each layer may vary. For example, if fibrillated fibers are included in the first layer, the average CSF value of the fibrillated fibers in the first layer can vary between about 10 mL and about 750 mL. In certain embodiments, the average CSF value of the fibrillated fibers used in the first layer can be greater than or equal to 1 mL, greater than or equal to about 10 mL, greater than or equal to about 20 mL, greater than or equal to about 35 mL, greater than or equal to about 45mL, greater than or equal to about 50mL, greater than or equal to about 65mL, greater than or equal to about 70mL, greater than or equal to about 75mL, greater than or equal to about 80mL, greater than or equal to about 100mL, greater than or equal to about 150mL, greater than or equal to about 175mL, About 200 mL or more, about 250 mL or more, about 300 mL or more, about 350 mL or more, about 500 mL or more, about 600 mL or more, about 650 mL or more, about 700 mL or more, or Or equal to about 750mL.

In some embodiments, the average CSF value of the fibrillated fibers used in the first layer can be about 750 mL or less, about 700 mL or less, about 650 mL or less, about 600 mL or less, about 600 mL or less. 550mL, less than or equal to about 500mL, less than or equal to about 450mL, less than or equal to about 400mL, less than or equal to about 350mL, less than or equal to about 300mL, less than or equal to about 250mL, less than or equal to about 225mL, less than or equal to about 200mL, About 150 mL or less, about 100 mL or less, about 90 mL or less, about 85 mL or less, about 70 mL or less, about 50 mL or less, about 40 mL or less, or about 25 mL or less. Combinations of the above ranges are also possible (eg, an average CSF value of fibrillated fibers greater than or equal to about 10 mL and less than or equal to about 300 mL). Other ranges are also possible. The average CSF value of the fibrillated fibers used in the first layer may be based on one type of fibrillated fiber or on more than one type of fibrillated fiber.

If fibrillated fibers are included in the second layer, the average CSF value of the fibrillated fibers in the second layer can vary from about 10 mL to about 750 mL. In certain embodiments, the average CSF value of the fibrillated fibers used in the second layer can be greater than or equal to 1 mL, greater than or equal to about 10 mL, greater than or equal to about 20 mL, greater than or equal to about 35 mL, greater than or equal to about 45mL, greater than or equal to about 50mL, greater than or equal to about 65mL, greater than or equal to about 70mL, greater than or equal to about 75mL, greater than or equal to about 80mL, greater than or equal to about 100mL, greater than or equal to about 150mL, greater than or equal to about 175mL, About 200 mL or more, about 250 mL or more, about 300 mL or more, about 350 mL or more, about 500 mL or more, about 600 mL or more, about 650 mL or more, about 700 mL or more, or Or equal to about 750mL.

In some embodiments, the average CSF value of the fibrillated fibers used in the second layer can be less than or equal to about 750 mL, less than or equal to about 700 mL, less than or equal to about 650 mL, less than or equal to about 600 mL, less than or equal to about 550mL, less than or equal to about 500mL, less than or equal to about 450mL, less than or equal to about 400mL, less than or equal to about 350mL, less than or equal to about 300mL, less than or equal to about 250mL, less than or equal to about 225mL, less than or equal to about 200mL, About 150 mL or less, about 100 mL or less, about 90 mL or less, about 85 mL or less, about 70 mL or less, about 50 mL or less, about 40 mL or less, or about 25 mL or less. Combinations of the above ranges are also possible (eg, an average CSF value of fibrillated fibers greater than or equal to about 10 mL and less than or equal to about 300 mL). Other ranges are also possible. The average CSF value of the fibrillated fibers used in the second layer may be based on one type of fibrillated fiber or on more than one type of fibrillated fiber.

The fibrillated fibers may be formed from any suitable material, such as synthetic materials (e.g., synthetic polymers such as polyester, polyamide, polyaramid, para-aramid, meta-aramid, polyimide, polyethylene , polypropylene, polyether ether ketone, polyethylene terephthalate, polyolefins, nylon, acrylics, regenerated cellulose (e.g. lyocell, rayon), liquid crystal polymers (e.g. polyethylene Phenyl-2,6-benzobis oxazole (PBO), polyester-based liquid crystal polymers such as polyester produced by polycondensation of 4-hydroxybenzoic acid and 6-hydroxynaphthalene-2-carboxylic acid), and natural materials (for example, natural polymers such as cellulose (for example , non-regenerated cellulose), organic fibers such as wool)). In some embodiments, organic polymer fibers are used. In some embodiments, carbon fibers are used.

In some embodiments, the fibrillated fibers may be synthetic fibers. Synthetic fibers, as used herein, are non-naturally occurring fibers formed from polymeric materials. Fibrillated fibers can also be non-synthetic materials, eg, naturally occurring cellulose fibers. Cellulosic fibers can include, for example, lignocellulosic fibers and non-lignocellulosic fibers. It is understood that the fibrillated fibers may comprise any suitable combination of synthetic fibers and/or non-synthetic fibers.

In certain embodiments, the fibrillated fibers are formed from lyocell fibers. Lyocell fibers are well known to those skilled in the art as a type of synthetic fiber and can be produced from regenerated cellulose by solvent spinning.

In certain embodiments, the fibrillated fibers are formed from rayon. Rayon is well known to those skilled in the art. It can also be produced from regenerated cellulose and can be produced using the acetate, cupro or viscose processes. In these methods, cellulose or cellulose solutions can be spun into fibers.

Fibers may be fibrillated by any suitable fibrillation refining process. In some embodiments, the fibers may be fibrillated using a disc refiner, beater, or any other suitable fibrillation equipment.

It should be understood that, in certain embodiments, the fibrillated fibers may have components other than those described above. For example, suitable components may include acrylics, liquid crystal polymers, poly Azole (e.g., poly(p-phenylene-2,6-benzobis azole), polyaramid, para-polyaramid, lignocellulose, non-lignocellulose, cotton, polyethylene, polyolefin and olefin, etc.

In general, fibrillated fibers can be of any suitable size (eg, as measured by microscopy).

As mentioned above, fibrillated fibers comprise precursor fibers and fibrils. The average diameter of the precursor fibers can be, for example, from about 1 micron to about 75 microns. In some embodiments, the average diameter of the precursor fibers can be 75 microns or less, 60 microns or less, 50 microns or less, 40 microns or less, 30 microns or less, 20 microns or less, or Less than or equal to 15 microns. In some embodiments, the average diameter of the precursor fibers can be about 10 microns or more, about 15 microns or more, about 20 microns or more, about 30 microns or more, about 40 microns or more, about 40 microns or more, or about 15 microns or more. Equal to about 50 microns, greater than or equal to about 60 microns, or greater than or equal to about 75 microns. Combinations of the above ranges are also possible (eg, precursor fibers having an average diameter of greater than or equal to about 15 microns and less than about 75 microns). Other ranges are also possible.

The average diameter of the fibrils can be, for example, from about 0.2 microns to about 15 microns. In some embodiments, the average diameter of the fibrils can be about 15 microns or less, about 10 microns or less, about 8 microns or less, about 6 microns or less, about 4 microns or less, or about 4 microns or less. Equal to about 3 microns, less than or equal to about 2 microns, or less than or equal to about 1 micron. In some embodiments, the fibrils may have an average diameter of about 0.2 microns or greater, about 1 micron or greater, about 2 microns or greater, about 3 microns or greater, about 4 microns or greater, or about 4 microns or greater. Equal to about 6 microns, greater than or equal to about 8 microns, or greater than or equal to about 10 microns. Combinations of the above ranges are also possible (eg, fibrils having an average diameter of greater than or equal to about 3 microns and less than about 6 microns). Other ranges are also possible.

The average length of the fibrillated fibers can be, for example, from about 1 mm to about 15 mm (eg, from about 0.2 mm to about 12 mm, or from about 2 mm to about 4 mm). In some embodiments, the average length of the fibrillated fibers can be about 15 mm or less, about 12 mm or less, about 10 mm or less, about 8 mm or less, about 6 mm or less, about 4 mm or less , or less than or equal to about 2mm. In certain embodiments, the average length of the fibrillated fibers can be about 2 mm or more, about 4 mm or more, about 6 mm or more, about 8 mm or more, about 10 mm or more, or about 10 mm or more. About 12mm. Combinations of the above ranges are also possible (eg, fibrillated fibers having an average length of greater than or equal to about 2 mm and less than about 12 mm). Other ranges are also possible. The average length of fibrillated fibers refers to the average length of the parent fiber from one end of the parent fiber to the opposite end. In some embodiments, the maximum average length of the fibrillated fibers falls within the above ranges. The maximum average length refers to the average value of the maximum dimension along one axis of the fibrillated fibers (comprising parent fibers and fibrils).

When the fibrillated fiber is a lyocell fiber or when the fibrillated fiber is a material other than a lyocell fiber, the above-mentioned size may be, for example, the above-mentioned size. It should be understood that in certain embodiments, the size of the fibers and fibrils may be outside the above ranges.

In general, fiber webs can contain any suitable weight percent of fibrillated fibers to achieve a desired balance of properties. In some embodiments, the weight percent of fibrillated fibers in the web is from about 1% to about 100% by weight (eg, from about 2% to about 60% by weight). For example, the weight percent of fibrillated fibers in the web can be greater than or equal to about 2 weight percent, greater than or equal to about 5 weight percent, greater than or equal to about 10 weight percent, greater than or equal to about 15 weight percent, greater than or equal to about 20 weight percent % by weight, greater than or equal to about 25% by weight, greater than or equal to about 30% by weight, greater than or equal to about 35% by weight, greater than or equal to about 40% by weight, greater than or equal to about 45% by weight, greater than or equal to about 50% by weight , or greater than or equal to about 60% by weight. In some embodiments, the weight percent of fibrillated fibers in the fiber web is less than or equal to about 100 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent, less than or equal to about 70 weight percent, less than or equal to Equal to about 60% by weight, less than or equal to about 55% by weight, less than or equal to about 50% by weight, less than or equal to about 45% by weight, less than or equal to about 40% by weight, less than or equal to about 35% by weight, less than or equal to about 30 wt%, less than or equal to about 25 wt%, less than or equal to about 20 wt%, less than or equal to about 15 wt%, less than or equal to about 10 wt%, or less than or equal to about 5 wt%. Combinations of the above ranges are also possible (eg, weight percentages greater than about 2% by weight and less than or equal to about 25% by weight). Other ranges are also possible.

In some embodiments, a fiber web having a greater amount of fibrillated fibers than other fiber webs may exhibit a relatively greater degree of flexibility and strength than other fiber webs, e.g., compared to other fiber webs. Ratio, elongation, tensile strength and/or burst strength increase.

In certain embodiments, a fiber web or a layer (eg, a first layer or a second layer) in a fiber web comprises fibrillated fibers having a relatively high degree of fibrillation. In some such embodiments, a smaller amount of fibrillated fibers may be required to achieve the same structure and/or properties as a fiber web having a relatively low degree of fibrillation of fibrillated fibers but having a large number of such fibers feature. In certain embodiments, a fiber web or a layer (e.g., a first layer or a second layer) in a fiber web comprises fibrillated fibers having an average CSF value of greater than or equal to about 10 mL and less than or equal to about 300 mL, About 250 mL or less, about 225 mL or less, about 200 mL or less, about 150 mL or less, about 100 mL or less, about 90 mL or less, about 85 mL or less, about 70 mL or less, or about 70 mL or less Equal to about 50 mL, less than or equal to about 40 mL, or less than or equal to about 25 mL. The weight percent of fibrillated fibers in such a web or a layer in the web can be, for example, greater than or equal to about 2% by weight (e.g., greater than or equal to about 5% by weight, greater than or equal to about 10% by weight, greater than or equal to Equal to about 15% by weight, greater than or equal to about 20% by weight, greater than or equal to about 25% by weight, greater than or equal to about 30% by weight, greater than or equal to about 35% by weight, greater than or equal to about 40% by weight, greater than or equal to about 45% by weight, greater than or equal to about 50% by weight, greater than or equal to about 60% by weight, greater than or equal to about 70% by weight, greater than or equal to about 80% by weight) and less than or equal to about 90% by weight, less than or equal to about 80% by weight % by weight, about 70% by weight or less, about 60% by weight or less, about 55% by weight or less, about 50% by weight or less, about 45% by weight or less, about 40% by weight or less , less than or equal to about 35 weight percent, less than or equal to about 30 weight percent, less than or equal to about 25 weight percent, less than or equal to about 20 weight percent, less than or equal to about 15 weight percent, less than or equal to about 10 weight percent, or Less than or equal to about 5% by weight. Other ranges are also possible.

In embodiments where the web comprises at least a first layer and a second layer, such as the embodiment shown illustratively in Figure 1, the weight percent of fibrillated fibers in each layer may also vary. For example, in some embodiments, the weight percent of fibrillated fibers in the first layer can be from about 0% to about 100% by weight. In some embodiments, the weight percent of fibrillated fibers in the first layer of the web may be greater than or equal to about 2 weight percent, greater than or equal to about 10 weight percent, greater than or equal to about 20 weight percent, greater than or equal to about 40 weight percent % by weight, greater than or equal to about 60% by weight, or greater than or equal to about 80% by weight. In some embodiments, the weight percent of fibrillated fibers in the first layer may be less than or equal to about 100 weight percent, less than or equal to about 80 weight percent, less than or equal to about 40 weight percent, less than or equal to about 20 weight percent, Less than or equal to about 10% by weight, or less than or equal to about 5% by weight. Combinations of the above ranges are also possible (eg, weight percentages greater than about 2% by weight and less than or equal to about 100% by weight). Other ranges are also possible.

In some embodiments, the weight percent of fibrillated fibers in the second layer can be from about 0% to about 100% by weight. In some embodiments, the weight percent of fibrillated fibers in the second layer of the web may be greater than or equal to about 1 weight percent, greater than or equal to about 2 weight percent, greater than or equal to about 5 weight percent, greater than or equal to about 10 weight percent. % by weight, greater than or equal to about 20% by weight, greater than or equal to about 30% by weight, greater than or equal to about 40% by weight, greater than or equal to about 50% by weight, greater than or equal to about 60% by weight, greater than or equal to about 70% by weight , greater than or equal to about 80% by weight, or greater than or equal to about 90% by weight. In some embodiments, the weight percent of fibrillated fibers in the second layer may be less than or equal to about 100 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent, less than or equal to about 70 weight percent, Less than or equal to about 60% by weight, less than or equal to about 50% by weight, less than or equal to about 40% by weight, less than or equal to about 30% by weight, less than or equal to about 20% by weight, less than or equal to about 15% by weight, less than or equal to Equal to about 10% by weight, or less than or equal to about 5% by weight. Combinations of the above ranges are also possible (eg, weight percentages greater than about 5% by weight and less than or equal to about 100% by weight). Other combinations are also possible.

As noted above, the amount of fibrillated fibers and the level of fibrillation can vary between the fibrous web layers of the filter media. For example, when the first layer of filter media is the upstream layer and the second layer of the filter media is the downstream layer, the relative amount of fibrillated fibers and the level of fibrillation can vary. In some embodiments, the upstream layer has a lesser degree of fibrillation (ie, greater average CSF) than the downstream layer. In other embodiments, the upstream layer has a greater degree of fibrillation than the downstream layer. In some embodiments, the percentage of fibrillated fibers in the upstream layer is relatively less than the percentage of fibrillated fibers in the downstream layer. In other embodiments, the percentage of fibrillated fibers in the upstream layer is greater than the percentage of fibrillated fibers in the downstream layer.

In certain embodiments where the fiber web comprises at least a first layer and a second layer, the second layer may comprise more fibrillated fibers than the first layer (e.g., at least 10%, at least 20%, at least 40%, at least 60%, at least 80%, at least 100%, at least 150%, at least 200%, at least 300%, at least 400%, at least 500%, or at least 1000% fibrillated fibers). In other embodiments, the first layer may comprise more fibrillated fibers (e.g., at least 10%, at least 20%, at least 40%, at least 60%, at least 80% more than the second layer) than the second layer. %, at least 100%, at least 150%, at least 200%, at least 300%, at least 400%, at least 500%, or at least 1000% of fibrillated fibers). Other ranges are also possible. In some cases, the same amount of fibrillated fibers is present in each layer. There may also be a gradient in the amount of fibrillated fibers across the thickness of the web.

In some embodiments where the fiber web comprises at least a first layer and a second layer, the second layer may comprise fibrillated fibers having a higher average level of fibrillation than the fibrillated fibers of the first layer. For example, the average CSF value of the fibrillated fibers of the second layer may be at least 10%, at least 20%, at least 40%, at least 60%, at least 80%, at least 100% greater than the average CSF value of the fibrillated fibers of the first layer %, at least 150%, at least 200%, at least 300%, at least 400%, or at least 500%. In other embodiments, the first layer may comprise fibrillated fibers having a higher average level of fibrillation than the fibrillated fibers of the second layer. For example, the average CSF value of the fibrillated fibers of the first layer may be at least 10%, at least 20%, at least 40%, at least 60%, at least 80%, at least 100% greater than the average CSF value of the fibrillated fibers of the second layer %, at least 150%, at least 200%, at least 300%, at least 400%, or at least 500%. Other ranges are also possible. In some cases, the fibrillated fibers in each layer have the same level of fibrillation. There may also be a gradient in the average fibrillation level across the thickness of the web.

In some cases, it may be advantageous to have fibrillated fibers in the machine direction of the web (i.e., when the length of the fibers extends substantially in the machine direction) and/or in the cross-machine direction of the web. (ie, when the length of the fiber extends substantially in the cross-machine direction). It should be understood that the terms "machine direction" and "cross-machine direction" have their conventional meanings in the art. That is, machine direction refers to the direction in which the web moves along the processing machine during processing, and cross-machine refers to the direction perpendicular to the machine direction.

In some embodiments, the fiber webs described herein may comprise cellulosic fibers. As described herein, cellulosic fibers can be fibrillated or non-fibrillated. Mixtures of fibrillated or non-fibrillated cellulose fibers are also possible. Cellulosic fibers may include any suitable type of cellulosic fibers, such as softwood fibers, hardwood fibers, and mixtures thereof. In addition, cellulosic fibers can include natural cellulosic fibers, synthetic cellulosic fibers (eg, regenerated cellulose), or mixtures thereof.

The fiber web may contain a suitable percentage of cellulosic fibers. For example, in some embodiments, the weight percent of cellulose fibers in the web can be from about 0% to about 100% by weight. In some embodiments, the weight percent of cellulosic fibers in the fiber web can be greater than or equal to about 5% by weight, greater than or equal to about 10% by weight, greater than or equal to about 30% by weight, greater than or equal to about 50% by weight, greater than or equal to Or about 70 wt%, greater than or equal to about 80 wt%, greater than or equal to about 90 wt%, greater than or equal to about 95 wt%, or greater than or equal to about 98 wt%. In some embodiments, the weight percent of cellulosic fibers in the fiber web can be less than or equal to about 100 weight percent, less than or equal to about 98 weight percent, less than or equal to about 95 weight percent, less than or equal to about 90 weight percent, less than or equal to or about 80% by weight, less than or equal to about 70% by weight, less than or equal to about 50% by weight, less than or equal to about 40% by weight, less than or equal to about 20% by weight, less than or equal to about 10% by weight, or less than or equal to Equivalent to about 5% by weight. Combinations of the above ranges are also possible (eg, weight percentages greater than about 5% by weight and less than or equal to about 80% by weight). Other ranges are also possible. In some embodiments, the fiber web comprises 0% by weight cellulosic fibers. In other embodiments, the fiber web comprises 100% by weight cellulosic fibers.

In embodiments where the web comprises at least a first layer and a second layer, such as the embodiment shown illustratively in Figure 1, the weight percent of cellulosic fibers in each layer may also vary. For example, in some embodiments, the weight percent of cellulose fibers in the first layer of the web can be from about 0% to about 100% by weight. In some embodiments, the weight percent of cellulosic fibers in the first layer of the web can be greater than or equal to about 10 weight percent, greater than or equal to about 30 weight percent, greater than or equal to about 50 weight percent, greater than or equal to about 70 weight percent % by weight, greater than or equal to about 80% by weight, greater than or equal to about 90% by weight, or greater than or equal to about 95% by weight. In some embodiments, the weight percent of cellulose fibers in the first layer of the web can be less than or equal to about 100 weight percent, less than or equal to about 95 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent % by weight, about 70% by weight or less, about 50% by weight or less, about 40% by weight or less, about 20% by weight or less, or about 10% by weight or less. Combinations of the above ranges are also possible (eg, weight percentages greater than about 5% by weight and less than or equal to about 80% by weight). Other ranges are also possible. In some embodiments, the first layer of the web comprises 0% by weight cellulosic fibers. In other embodiments, the first layer of the web comprises 100% by weight cellulosic fibers.

In some embodiments, the weight percent of cellulose fibers in the second layer of the web can be from about 0% to about 100% by weight. In some embodiments, the weight percent of cellulosic fibers in the second layer of the web may be greater than or equal to about 5% by weight, greater than or equal to about 10% by weight, greater than or equal to about 30% by weight, greater than or equal to about 50% by weight % by weight, greater than or equal to about 70% by weight, greater than or equal to about 80% by weight, greater than or equal to about 90% by weight, or greater than or equal to about 95% by weight. In some embodiments, the weight percent of cellulosic fibers in the second layer of the web can be less than or equal to about 100 weight percent, less than or equal to about 95 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent % by weight, about 70% by weight or less, about 50% by weight or less, about 40% by weight or less, about 20% by weight or less, or about 10% by weight or less. Combinations of the above ranges are also possible (eg, weight percentages greater than about 5% by weight and less than or equal to about 80% by weight). Other ranges are also possible. In some embodiments, the second layer of the web comprises 0% by weight cellulosic fibers. In other embodiments, the second layer of the web comprises 100% by weight cellulosic fibers.

The fiber web may comprise any suitable amount of hardwood fibers and/or softwood fibers, which may be fibrillated or non-fibrillated. Mixtures of fibrillated and non-fibrillated hardwood fibers and/or softwood fibers are also possible.

In some embodiments, the weight percent of hardwood fibers in the fiber web can be from about 0% to about 98% by weight. In some embodiments, the weight percent of hardwood fibers in the fiber web may be greater than or equal to about 5 weight percent, greater than or equal to about 10 weight percent, greater than or equal to about 30 weight percent, greater than or equal to about 50 weight percent, greater than or equal to Equal to about 70 wt%, greater than or equal to about 80 wt%, greater than or equal to about 90 wt%, or greater than or equal to about 98 wt%. In some embodiments, the weight percent of hardwood fibers in the fiber web can be less than or equal to about 98 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent, less than or equal to about 70 weight percent, less than or equal to Equal to about 50 wt%, Less than or equal to about 40 wt%, Less than or equal to about 20 wt%, Less than or equal to about 10 wt%, or Less than or equal to about 5 wt%. Combinations of the above ranges are also possible (eg, weight percentages greater than about 5% by weight and less than or equal to about 90% by weight). Other ranges are also possible. In some embodiments, the fiber web comprises 0% by weight hardwood fibers.

In embodiments where the web comprises at least a first layer and a second layer, such as the embodiment shown illustratively in Figure 1, the weight percent of hardwood fibers in each layer may also vary. For example, in some embodiments, the weight percent of hardwood fibers in the first layer of the web can be from about 0% to about 100% by weight. In some embodiments, the weight percent of hardwood fibers in the first layer of the web may be greater than or equal to about 10 weight percent, greater than or equal to about 30 weight percent, greater than or equal to about 50 weight percent, greater than or equal to about 70 weight percent %, or greater than or equal to about 80% by weight. In some embodiments, the weight percent of hardwood fibers in the first layer of the web can be less than or equal to about 95 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent, less than or equal to about 70 weight percent %, less than or equal to about 50 wt%, less than or equal to about 40 wt%, less than or equal to about 20 wt%, or less than or equal to about 10 wt%. Combinations of the above ranges are also possible (eg, weight percentages greater than about 5% by weight and less than or equal to about 80% by weight). Other ranges are also possible.

In some embodiments, the weight percent of hardwood fibers in the second layer of the web can be from about 0% to about 100% by weight. In some embodiments, the weight percent of hardwood fibers in the second layer of the web may be greater than or equal to about 5 weight percent, greater than or equal to about 10 weight percent, greater than or equal to about 30 weight percent, greater than or equal to about 50 weight percent %, greater than or equal to about 70% by weight, or greater than or equal to about 80% by weight. In some embodiments, the weight percent of hardwood fibers in the second layer of the web may be less than or equal to about 95 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent, less than or equal to about 70 weight percent %, less than or equal to about 50 wt%, less than or equal to about 40 wt%, less than or equal to about 20 wt%, or less than or equal to about 10 wt%. Combinations of the above ranges are also possible (eg, weight percentages greater than about 5% by weight and less than or equal to about 80% by weight). Other ranges are also possible.

The weight percent of softwood fibers in the web can also vary. For example, the weight percent of softwood fibers in the web can be from about 0% to about 98% by weight. In some embodiments, the weight percent of softwood fibers in the fiber web may be greater than or equal to about 5 weight percent, greater than or equal to about 10 weight percent, greater than or equal to about 30 weight percent, greater than or equal to about 50 weight percent, greater than or equal to Equal to about 70 wt%, greater than or equal to about 80 wt%, greater than or equal to about 90 wt%, or greater than or equal to about 98 wt%. In some embodiments, the weight percent of softwood fibers in the web may be less than or equal to about 98 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent, less than or equal to about 70 weight percent, less than or equal to Equal to about 50 wt%, Less than or equal to about 40 wt%, Less than or equal to about 20 wt%, Less than or equal to about 10 wt%, or Less than or equal to about 5 wt%. Combinations of the above ranges are also possible (eg, weight percentages greater than about 5% by weight and less than or equal to about 80% by weight). Other ranges are also possible. In some embodiments, the fiber web comprises 0% by weight softwood fibers.

In embodiments where the web comprises at least a first layer and a second layer, such as the embodiment shown illustratively in Figure 1, the weight percent of softwood fibers in each layer may also vary. For example, in some embodiments, the weight percent of softwood fibers in the first layer of the web can be from about 0% to about 100% by weight. In some embodiments, the weight percent of softwood fibers in the first layer of the web may be greater than or equal to about 10 weight percent, greater than or equal to about 30 weight percent, greater than or equal to about 50 weight percent, greater than or equal to about 70 weight percent %, or greater than or equal to about 80% by weight. In some embodiments, the weight percent of softwood fibers in the first layer of the web may be less than or equal to about 95 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent, less than or equal to about 70 weight percent %, less than or equal to about 50 wt%, less than or equal to about 40 wt%, less than or equal to about 20 wt%, or less than or equal to about 10 wt%. Combinations of the above ranges are also possible (eg, weight percentages greater than about 5% by weight and less than or equal to about 80% by weight). Other ranges are also possible.

In some embodiments, the weight percent of softwood fibers in the second layer of the web can be from about 0% to about 100% by weight. In some embodiments, the weight percent of softwood fibers in the second layer of the web may be greater than or equal to about 5 weight percent, greater than or equal to about 10 weight percent, greater than or equal to about 30 weight percent, greater than or equal to about 50 weight percent %, greater than or equal to about 70% by weight, or greater than or equal to about 80% by weight. In some embodiments, the weight percent of softwood fibers in the second layer of the web may be less than or equal to about 95 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent, less than or equal to about 70 weight percent %, less than or equal to about 50 wt%, less than or equal to about 40 wt%, less than or equal to about 20 wt%, or less than or equal to about 10 wt%. Combinations of the above ranges are also possible (eg, weight percentages greater than about 5% by weight and less than or equal to about 80% by weight). Other ranges are also possible.

In some embodiments, the fiber webs described herein comprise one or more synthetic fibers. As described herein, the synthetic fibers may be fibrillated or non-fibrillated. Synthetic fibers may comprise any suitable type of synthetic polymer. Examples of suitable non-fibrillated synthetic fibers include polyesters (e.g., polyethylene terephthalate, polybutylene terephthalate), polyamides, polyaramids, para-aramids, Meta-aramide, polyaniline, polyimide, polyethylene, polypropylene, polyether ether ketone, polyolefin, nylon, acrylic, polyvinyl alcohol, regenerated cellulose (e.g. lyocell, rayon) , cellulose acetate, polyvinylidene fluoride, poly(vinylidene fluoride-co-hexafluoropropylene), polyacrylonitrile, polysulfone (e.g., polyethersulfone, poly(phenylene ethersulfone)), Polystyrene, polybutadiene, polyurethane, polyphenylene oxide, polycarbonate, poly(methyl methacrylate), poly(hydroxyethyl methacrylate), poly(lactic acid) or polylactide, silk, poly(4 -methyl-1-pentene), polypyrrole, and combinations thereof. In some embodiments, one or more fibers may include a copolymer as described above (eg, a polystyrene-polybutadiene block copolymer). In some embodiments, the synthetic fibers are organic polymer fibers.

Synthetic fibers may also include multicomponent fibers (ie, fibers having multiple components, such as bicomponent fibers) comprising one or more of the polymers described above. For example, sea-island fibers can be used. In some cases, the synthetic fibers can include meltblown fibers, which can be formed from the fibers described herein (eg, polyester, polypropylene). In other cases, the synthetic fibers can be electrospun fibers. In yet other embodiments, the synthetic fibers may be spin-spun fibers or melt-spun fibers.

The web and the first and/or second layer of the web may also comprise a combination of more than one type of synthetic fiber. It should be understood that other types of synthetic fiber types may also be used.

The fiber web may contain a suitable percentage of synthetic fibers. For example, in some embodiments, the weight percent of synthetic fibers in the web can be from about 0% to about 100% by weight. In some embodiments, the weight percent of synthetic fibers in the fiber web can be greater than or equal to about 5 weight percent, greater than or equal to about 10 weight percent, greater than or equal to about 30 weight percent, greater than or equal to about 50 weight percent, greater than or equal to Equal to about 70 wt%, greater than or equal to about 80 wt%, greater than or equal to about 90 wt%, or greater than or equal to about 95 wt%. In some embodiments, the weight percent of synthetic fibers in the fiber web can be less than or equal to about 100 weight percent, less than or equal to about 95 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent, less than or equal to Equal to about 70 wt%, Less than or equal to about 50 wt%, Less than or equal to about 40 wt%, Less than or equal to about 20 wt%, or Less than or equal to about 10 wt%. Combinations of the above ranges are also possible (eg, weight percentages greater than about 50% by weight and less than or equal to about 100% by weight). Other ranges are also possible. In some embodiments, the fiber web comprises 100% by weight synthetic fibers. In other embodiments, the fiber web comprises 0% by weight synthetic fibers.

In certain embodiments, the fiber web comprises one or more inorganic fibers. Inorganic fibers may include, for example, ceramic fibers such as oxides (eg, alumina, titania, tin oxide, zinc oxide). Mineral fibers may also be included in the fiber web. Inorganic fibers may also include metal fibers such as stainless steel fibers, nickel-plated fibers, and copper-plated fibers.

In embodiments where the web comprises at least a first layer and a second layer, such as the embodiment shown illustratively in Figure 1, the weight percent of synthetic fibers in each layer may also vary. For example, in some embodiments, the weight percent of synthetic fibers in the first layer of the web can be from about 0% to about 100% by weight. In some embodiments, the weight percent of synthetic fibers in the first layer of the web may be greater than or equal to about 10 weight percent, greater than or equal to about 30 weight percent, greater than or equal to about 50 weight percent, greater than or equal to about 70 weight percent %, or greater than or equal to about 80% by weight, greater than or equal to about 90% by weight, or greater than or equal to about 95% by weight. In some embodiments, the weight percent of synthetic fibers in the first layer of the web can be less than or equal to about 100 weight percent, less than or equal to about 95 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent %, less than or equal to about 70 wt%, less than or equal to about 50 wt%, less than or equal to about 40 wt%, less than or equal to about 20 wt%, or less than or equal to about 10 wt%. Combinations of the above ranges are also possible (eg, weight percentages greater than about 50% by weight and less than or equal to about 100% by weight). Other ranges are also possible. In some embodiments, the first layer of the web comprises 0% by weight synthetic fibers. In other embodiments, the first layer of the web comprises 100% by weight synthetic fibers.

In some embodiments, the weight percent of synthetic fibers in the second layer of the web can be from about 0% to about 100% by weight. In some embodiments, the weight percent of synthetic fibers in the second layer of the web may be greater than or equal to about 10 weight percent, greater than or equal to about 30 weight percent, greater than or equal to about 50 weight percent, greater than or equal to about 70 weight percent %, or greater than or equal to about 80% by weight, greater than or equal to about 90% by weight, or greater than or equal to about 95% by weight. In some embodiments, the weight percent of synthetic fibers in the second layer of the web can be less than or equal to about 100 weight percent, less than or equal to about 95 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent %, less than or equal to about 70 wt%, less than or equal to about 50 wt%, less than or equal to about 40 wt%, less than or equal to about 20 wt%, or less than or equal to about 10 wt%. Combinations of the above ranges are also possible (eg, weight percentages greater than about 50% by weight and less than or equal to about 100% by weight). Other ranges are also possible. In some embodiments, the second layer of the web comprises 100% by weight synthetic fibers.

The fiber webs described herein may also comprise non-fibrillated synthetic fibers (eg, staple fibers); ie, non-fibrillated synthetic fibers. As noted above, synthetic fibers are non-naturally occurring fibers formed from polymeric materials. Non-fibrillated synthetic fibers include any suitable type of synthetic polymer, including generally thermoplastic polymers and those polymers used herein to describe synthetic fibers. Examples of suitable non-fibrillated synthetic fibers include polyester, polyamide, polyaramid, polyimide, polyethylene, polypropylene, polyether ether ketone, polyethylene terephthalate, polyolefin, Nylon, and combinations thereof. It should be understood that other types of non-fibrillated synthetic fiber types may also be used.

In general, non-fibrillated synthetic fibers can be of any suitable size. For example, the average diameter of the non-fibrillated synthetic fibers can be from about 2 microns to about 50 microns, from about 2 microns to about 20 microns, from about 4 microns to about 7 microns, or from about 3 microns to about 7 microns. In some embodiments, the average diameter of the non-fibrillated synthetic fibers can be about 1 micron or greater, about 2 microns or greater, about 4 microns or greater, about 6 microns or greater, about 8 microns or greater. microns, greater than or equal to about 10 microns, greater than or equal to about 12 microns, greater than or equal to about 15 microns, greater than or equal to about 20 microns, greater than or equal to about 30 microns, or greater than or equal to about 40 microns. In some cases, the average diameter of the non-fibrillated synthetic fibers can be about 50 microns or less, about 40 microns or less, about 30 microns or less, about 20 microns or less, about 15 microns or less , less than or equal to about 12 microns, less than or equal to about 10 microns, less than or equal to about 8 microns, less than or equal to about 6 microns, less than or equal to about 4 microns, or less than or equal to about 2 microns. Combinations of the above ranges are also possible (eg, an average diameter of greater than or equal to about 2 microns and less than about 10 microns). Other ranges are also possible.

In some embodiments, a web of non-fibrillated synthetic fibers having a larger average diameter may exhibit a higher degree of permeability than a web of non-fibrillated synthetic fibers having a relatively smaller average diameter . The average length of the non-fibrillated synthetic fibers may be from about 3 mm to about 12 mm, from about 4 mm to about 6 mm, or from about 5 mm to about 7 mm. In some embodiments, a web of non-fibrillated synthetic fibers having a larger average length may exhibit a higher degree of stretching than a web of non-fibrillated synthetic fibers having a relatively smaller average length strength. It should be understood that, in certain embodiments, the non-fibrillated synthetic fibers may have dimensions outside the above ranges.

In some embodiments, the non-fibrillated synthetic fibers may be staple fibers, which may be synthetic fibers that are cut or formed into non-continuous discrete fibers of suitable average length and suitable for incorporation into wet-laid synthetic fibers. Web or non-wet-laid (eg, dry-laid, air-laid) processes to form fiber webs. In some cases, groups of staple fibers may be cut to specific lengths with only slight variations in length between individual fibers.

In some embodiments, the non-fibrillated synthetic fibers may be binder fibers. Non-fibrillated synthetic fibers can be monocomponent (i.e., have a single composition, such as polyvinyl alcohol or other polymers as described herein) or multicomponent (i.e., have multiple compositions, such as bis component fibers). Combinations of different non-fibrillated synthetic fibers are also possible.

In some embodiments, a fiber web may comprise a suitable percentage of monocomponent fibers and/or multicomponent fibers. In some embodiments, all of the non-fibrillated synthetic fibers are monocomponent fibers. In some embodiments, at least a portion of the non-fibrillated synthetic fibers are multicomponent fibers.

An example of a multicomponent fiber is a bicomponent fiber comprising a first material and a second material different from the first material. The different components of a multicomponent fiber can exhibit various spatial arrangements. For example, multicomponent fibers can be arranged in a core-sheath configuration (e.g., a first material can be a sheath material surrounding a second material that is a core material), a side-by-side configuration (e.g., a first material can be separated from a second material). adjacent arrangement), a segmented pie arrangement (for example, different materials can be arranged next to each other in a wedge-shaped configuration), a trilobal arrangement (for example, the tips of the leaves can be of a different material than the leaves) and a Configuration of local regions of components in different components (eg, "islands in the sea" pattern).

In some embodiments, for a core-sheath configuration, a multicomponent fiber (eg, a bicomponent fiber) can comprise a sheath of a first material surrounding a core comprising a second material. For some embodiments, in such an arrangement, the melting point of the first material may be lower than the melting point of the second material. Thus, at an appropriate step during the manufacture of the web (e.g., drying), the shell comprising the first material may melt (e.g., may exhibit a phase change), while the core comprising the second material remains unchanged (e.g., may exhibit a phase change). no phase change). For example, the melting temperature of the sheath portion of the multicomponent fiber can be from about 50°C to about 200°C (eg, about 180°C), while the melting temperature of the inner core of the multicomponent fiber can be greater than 200°C. Thus, when the fiber is subjected to a temperature of eg 180°C during drying, the outer shell of the fiber may melt while the core of the fiber does not.

The fiber web may contain a suitable percentage of non-fibrillated synthetic fibers. For example, in some embodiments, the weight percent of non-fibrillated synthetic fibers in the web can be from about 0% to about 98% by weight. In some embodiments, the weight percent of non-fibrillated synthetic fibers in the web may be greater than or equal to about 5 weight percent, greater than or equal to about 10 weight percent, greater than or equal to about 30 weight percent, greater than or equal to about 50 weight percent %, greater than or equal to about 70% by weight, or greater than or equal to about 80% by weight. In some embodiments, the weight percent of non-fibrillated synthetic fibers in the web can be less than or equal to about 95 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent, less than or equal to about 70 weight percent %, less than or equal to about 50 wt%, less than or equal to about 40 wt%, less than or equal to about 20 wt%, or less than or equal to about 10 wt%. Combinations of the above ranges are also possible (eg, weight percentages greater than about 5% by weight and less than or equal to about 80% by weight). Other ranges are also possible. In some embodiments, the fiber web comprises 0% by weight non-fibrillated synthetic fibers.

In embodiments where the web comprises at least a first layer and a second layer, such as the embodiment shown illustratively in FIG. 1 , the weight percent of non-fibrillated synthetic fibers (e.g., staple fibers) in each layer is also subject to change. For example, in some embodiments, the weight percent of non-fibrillated synthetic fibers in the first layer of the web can be from about 0% to about 100% by weight. In some embodiments, the weight percent of non-fibrillated synthetic fibers in the first layer of the web may be greater than or equal to about 10 weight percent, greater than or equal to about 30 weight percent, greater than or equal to about 50 weight percent, greater than or equal to Equal to about 70% by weight, or greater than or equal to about 80% by weight. In some embodiments, the weight percent of non-fibrillated synthetic fibers in the first layer of the web may be less than or equal to about 95 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent, less than or equal to Equal to about 70 wt%, Less than or equal to about 50 wt%, Less than or equal to about 40 wt%, Less than or equal to about 20 wt%, or Less than or equal to about 10 wt%. Combinations of the above ranges are also possible (eg, weight percentages greater than about 5% by weight and less than or equal to about 80% by weight). Other ranges are also possible. In some embodiments, the first layer of the web comprises 0% by weight non-fibrillated synthetic fibers. In other embodiments, the first layer of the web comprises 100% by weight non-fibrillated synthetic fibers.

In some embodiments, the weight percent of non-fibrillated synthetic fibers in the second layer of the web can be from about 0% to about 98% by weight. In some embodiments, the weight percent of non-fibrillated synthetic fibers in the second layer of the web may be greater than or equal to about 10 weight percent, greater than or equal to about 30 weight percent, greater than or equal to about 50 weight percent, greater than or equal to Equal to about 70% by weight, or greater than or equal to about 80% by weight. In some embodiments, the weight percent of non-fibrillated synthetic fibers in the second layer of the web may be less than or equal to about 95 weight percent, less than or equal to about 90 weight percent, less than or equal to about 80 weight percent, less than or equal to Equal to about 70 wt%, Less than or equal to about 50 wt%, Less than or equal to about 40 wt%, Less than or equal to about 20 wt%, or Less than or equal to about 10 wt%. Combinations of the above ranges are also possible (eg, weight percentages greater than about 5% by weight and less than or equal to about 80% by weight). Other ranges are also possible. In some embodiments, the second layer of the web comprises 0% by weight non-fibrillated synthetic fibers.

In some embodiments, a fiber web may comprise multiple types of non-fibrillated synthetic fibers.

The fiber web may contain a limited amount of glass fibers, if any. For example, the weight percent of glass fibers in the web can be from about 0% to about 20% by weight (e.g., from about 0% to about 10%, from about 0% to about 5%, from about 0% to about 2% by weight, or from about 0% by weight to about 1% by weight). In some embodiments, the weight percent of glass fibers in the web can be less than or equal to about 20 weight percent, less than or equal to about 15 weight percent, less than or equal to about 10 weight percent, less than or equal to about 8 weight percent, less than or equal to Equal to about 6% by weight, less than or equal to about 5% by weight, less than or equal to about 4% by weight, less than or equal to about 2% by weight, or less than or equal to about 1% by weight. Other ranges are also possible. A fiber web is considered to be substantially free of glass fibers when the fiber web comprises less than about 1% by weight glass fibers.

In embodiments where the web comprises at least a first layer and a second layer, such as the embodiment shown illustratively in FIG. 1 , the weight percent of glass fibers in each layer may also vary. For example, in some embodiments, the weight percent of glass fibers in the first layer of the fiber web can be from about 0% to about 20% by weight (e.g., from about 0% to about 10%, from about 0% to about 5 wt%, about 0 wt% to about 2 wt%, or about 0 wt% to about 1 wt%). In some embodiments, the weight percent of glass fibers in the first layer of the fiber web can be less than or equal to about 20 weight percent, less than or equal to about 15 weight percent, less than or equal to about 10 weight percent, less than or equal to about 8 weight percent %, less than or equal to about 6 wt%, less than or equal to about 5 wt%, less than or equal to about 4 wt%, less than or equal to about 2 wt%, or less than or equal to about 1 wt%. In some cases, the first layer contains 0% by weight glass fibers. Other ranges are also possible.

In some embodiments, the weight percent of glass fibers in the second layer of the fiber web can be from about 0% to about 20% by weight (e.g., from about 0% to about 10%, from about 0% to about 5%) %, from about 0% by weight to about 2% by weight, or from about 0% by weight to about 1% by weight). In some embodiments, the weight percent of glass fibers in the second layer of the fiber web can be less than or equal to about 20 weight percent, less than or equal to about 15 weight percent, less than or equal to about 10 weight percent, less than or equal to about 8 weight percent %, less than or equal to about 6 wt%, less than or equal to about 5 wt%, less than or equal to about 4 wt%, less than or equal to about 2 wt%, or less than or equal to about 1 wt%. In some cases, the second layer contains 0% by weight glass fibers. Other ranges are also possible.

In some cases, fiber webs with a limited amount, if any, of glass fibers, when used with various machine or engine Significant reduction in wear and loss. A limited amount or absence of glass fibers can also reduce the amount of fibers shed from the fibrous media during installation or use. Thus, the use of a fiber web that includes little or no glass fibers therein reduces the need for the presence of a protective web that would otherwise be installed downstream of the filter media.

As noted above, the web may comprise additional layers (eg, third layer, fourth layer, ..., tenth layer, etc.). Additional layers may be provided upstream or downstream of the first layer, or upstream or downstream of the second layer. In some cases, additional layers may be disposed between the first and second layers. Furthermore, more than one additional layer (eg, up to 10 layers), which may be the same or different from one another, may be included in the web at different locations relative to the first or second layer.

Although other ranges are possible, in certain embodiments, the additional layer may have a basis weight of about 5 g/m ² to about 800 g/m ² , an air permeability of less than about 1300 cfm/sf, and an average fiber diameter of is less than 100 microns. In some embodiments, additional layers can be used to increase one of the dust holding capacity, longevity, liquid filtration efficiency, water separation efficiency, and/or strength (e.g., Mullen burst strength, tensile strength, elongation) of the fiber web or more, but other uses of additional layers are also possible.

In some embodiments, additional layers that may be used to increase the dust holding capacity of the web may have, for example, a weight per unit area of less than or equal to 300 g/m ² , an air permeability of less than or equal to 700 cfm/sf and an average air permeability of less than or equal to 20 microns. fiber diameter, but other ranges are also possible.

In some embodiments, additional layers that may be used to increase the efficiency of the web may have, for example, a weight per area of less than or equal to 100 ^g /m, an air permeability of less than or equal to 700 cfm/sf, and an average fiber diameter of less than or equal to 4 microns , but other ranges are also possible.

In some embodiments, additional layers that can be used to increase the water separation efficiency (e.g., fuel-water separation efficiency) of the web can have, for example, a weight per area of less than or equal to 800 ^g /m, an air permeability of less than or equal to 1300 cfm/sf Ratio and an average fiber diameter less than or equal to 50 microns, although other ranges are possible.

The additional layer may be formed from any suitable fibers and the layer may be nonwoven or woven. In some cases, the additional layer is non-wet-laid and comprises non-wet-laid fibers, e.g., meltblown fibers, melt-spun fibers, dry-laid (carded) fibers, spin-spun fibers, spunbond fibers and/or airlaid fibers. In some cases, the additional layer contains continuous fibers. In other cases, the additional layer comprises staple fibers (eg, fibers having a length of about 1 mm to about 55 mm). In some embodiments, the additional layer does not contain any fibrillated fibers, but in other embodiments may contain fibrillated fibers. Materials used to form the fibers of the additional layers may include materials described herein (eg, synthetic, organic, and/or inorganic materials).

In some cases, the additional layer may be in the form of a mesh. A mesh may be formed from any suitable material, such as those described herein (eg, synthetic, organic, and/or inorganic). In addition, metals such as stainless steel may be used. The mesh may have a suitable average pore size, such as from about 0.001 mm to about 7 mm (e.g., at least about 0.001 mm, at least about 0.01 mm, at least about 0.1 mm, at least about 1 mm, at least about 3 mm, or at least about 5 mm and/or less than or equal to about 7 mm, less than or equal to about 4 mm, less than or equal to about 2 mm, less than or equal to about 1 mm). Other ranges are also possible.

In general, the fibers of the additional layer can be of any suitable size. For example, the average diameter of the additional layer fibers can be from about 100 nm to about 100 microns (e.g., from about 100 nm to about 50 microns, from about 100 nm to about 4 microns, from about 1 micron to about 20 microns, or from about 1 micron to about 50 microns) . In some embodiments, the average diameter of the additional layer can be greater than or equal to about 100 nm, greater than or equal to about 1 micron, greater than or equal to about 2 microns, greater than or equal to about 4 microns, greater than or equal to about 10 microns, greater than or equal to About 15 microns, greater than or equal to about 20 microns, greater than or equal to about 30 microns, or greater than or equal to about 40 microns. In some cases, the average diameter of the fibers of the additional layer may be about 50 microns or less, about 40 microns or less, about 30 microns or less, about 20 microns or less, about 15 microns or less, or about 15 microns or less. Equal to about 10 microns, less than or equal to about 8 microns, less than or equal to about 6 microns, less than or equal to about 4 microns, or less than or equal to about 2 microns, or less than or equal to about 1 micron. Combinations of the above ranges are also possible. Other ranges are also possible.

In some embodiments, the length of the fibers in the additional layer can vary from about 1 mm to about 20 cm (e.g., at least about 1 mm, at least about 5 mm, at least about 10 mm, at least about 50 mm, at least about 1 cm, at least about 5 cm, at least about 10 cm and/or less than or equal to about 20 cm, less than or equal to about 15 cm, less than or equal to about 10 cm, less than or equal to about 5 cm, less than or equal to about 1 cm, less than or equal to about 50 mm, less than or equal to about 20 mm, or less than or equal to equal to about 10mm). Other ranges are also possible. Continuous fibers may also be included.

In one set of embodiments, the filter media comprises a first layer and/or a second layer in combination with additional layers described herein. The first layer and/or the second layer may be a wet-laid layer (eg, a layer formed by a wet-laying process). The additional layer can be a non-wet-laid layer (eg, it can comprise meltblown fibers, melt-spun fibers, spin-spun fibers, electrospun fibers, or fibers formed by other non-wet-laid processes). Typically, the first and/or second layer comprises a plurality of synthetic fibers and/or organic polymer fibers. For example, in one such embodiment, the filter media comprises a first layer comprising a plurality of organic polymer fibers and a second layer comprising a plurality of synthetic fibers. In some embodiments, at least one of the first layer and/or the second layer is present in an amount described herein (e.g., from about 1% to about 100% by weight of the first layer and/or the second layer) Contains fibrillated fibers. Additionally, the first layer and/or the second layer can comprise from about 0% to about 10% by weight glass fibers (eg, the first layer and/or the second layer can be substantially free of glass fibers). In some embodiments, the first layer and/or the second layer can be configured to have one or more of the following: [mean flow pore size (μm)/(permeability (cfm/sf)) less than about 3.0 ^0.5 ] value; a dust holding capacity of greater than or equal to about 80 g/m ² ; and/or a liquid filtration efficiency of at least 98% for particles of 4 microns or larger. Additional layers that can be used to increase one or more of the fiber web's dust holding capacity, longevity, liquid filtration efficiency, water separation efficiency, and/or strength (e.g., Mullen burst strength, tensile strength, elongation) can be Contains synthetic polymer fibers. The additional layer may have, for example, a basis weight of from about ⁵ g/ ^m2 to about 800 g/m2, an air permeability of less than about 100 cfm/sf, and an average fiber diameter of less than 100 microns. In some embodiments, the entire filter media can have a weight per unit area of greater than about 10 g/m ² and less than or equal to about 1000 g/m ² , and can have a thickness of about 0.1 mm to about 10.0 mm. Advantageously, in some embodiments involving filter media comprising a first layer, a second layer, and additional layers, the filter media can achieve an efficiency of at least 99% at 4 microns, an initial efficiency of at least 99%, and a dust holding capacity of at least 150 gsm quantity. Other performance values are also possible. In some embodiments, the filter media can achieve a fuel-water separation efficiency of at least about 30% (eg, about 60% to about 99.9%, about 80% to about 99.9%, or about 90% to about 99.9%).

In some embodiments, the fiber web may include a binder resin. The binder resin is not in fiber form and is distinct from the binder fibers (eg, multicomponent fibers) described above. In general, the binder resin can have any suitable composition. For example, the binder resin may include a thermoplastic resin (eg, acrylic resin, polyvinyl acetate, polyester, polyamide), a thermosetting resin (eg, epoxy resin, phenolic resin), or a combination thereof. In some cases, the binder resin includes one of vinyl acetate resins, epoxy resins, polyester resins, copolyester resins, polyvinyl alcohol resins, acrylic resins (such as styrene acrylic resins), and phenolic resins or more. Other resins are also possible

The amount of binder resin in the web can vary. For example, the weight percentage of the binder resin in the fiber web may be 0% to 45% by weight. In some embodiments, the weight percentage of the binder resin in the fiber web can be greater than or equal to about 2% by weight, greater than or equal to about 5% by weight, greater than or equal to about 10% by weight, greater than or equal to about 15% by weight, Greater than or equal to about 20 wt%, greater than or equal to about 25 wt%, greater than or equal to about 30 wt%, greater than or equal to about 35 wt%, or greater than or equal to about 40 wt%. In some cases, the weight percent of the binder resin in the fiber web can be less than or equal to about 45 weight percent, less than or equal to about 40 weight percent, less than or equal to about 35 weight percent, less than or equal to about 30 weight percent, less than or equal to Or about 25 wt%, less than or equal to about 20 wt%, less than or equal to about 15 wt%, less than or equal to about 10 wt%, or less than or equal to about 5 wt%. Combinations of the above ranges are also possible (eg, weight percentages greater than or equal to about 5% by weight and less than about 35% by weight). Other ranges are also possible.

As described further below, the binder resin may be added to the fibers in any suitable manner including, for example, in the wet web state. In some embodiments, the binder coats the fibers and is used to adhere the fibers to each other to promote adhesion between fibers. Fibers may be coated using any suitable method or equipment, for example, using curtain coating, gravure coating, melt coating, dip coating, knife coating, spin coating, and the like. In some embodiments, the binder precipitates when added to the fiber blend. Where appropriate, any suitable precipitant (eg, epichlorohydrin, fluorocarbon) may be provided to the fibers, eg, by injection into the blend. In some embodiments, when added to the fiber blend, the binder resin, when added to the fiber blend, is in such a manner that the fiber web is impregnated with the binder resin (e.g., adhesive Binder resin penetrates the entire fiber web) is added. In other embodiments, the binder resin may be added to one or both sides of the layer or web after the layer or web is dried (eg, after being formed using a wet-laid process).

In a multilayer web, the binder resin may be added to one or more layers or to each layer individually before combining the layers, or the binder resin may be added to the web after combining the layers. In some embodiments, the binder resin is added to the first layer and/or the second layer, for example, by spray coating or saturated dipping (eg, a solvent saturation process), or any of the methods described above.

In some embodiments, the binder resin or binder mixture may be added to the first and/or second layer of the web by a solvent saturation process. In certain embodiments, the polymeric material may be impregnated into the first layer and/or the second layer during or after manufacture of the layers on a paper machine. For example, during the manufacturing process described herein, after the article comprising the first and second layers is formed and dried, the polymeric material in a water-based emulsion or in an organic solvent-based solution can be adhered to an applicator roll and then placed on the It is applied to the article under controlled pressure by using a size press or a gravure saturator. The amount of polymeric material impregnated into the article generally depends on the viscosity, solids content and absorbency of the article.

As another example, after the web is formed, it can be obtained by using a reverse roll coater after the just mentioned method and/or by using a dip and squeeze method (e.g., by dipping a dry filter medium into a polymer emulsion or The solution then impregnates the web with polymer material by squeezing out excess polymer using a nip. The polymeric material may also be applied to the web by using other methods known in the art, such as spraying or foaming.

It should be understood that the fiber web may or may not contain other components than those described above. Typically, any additional components are present in limited amounts, eg, less than 5% by weight. For example, in some embodiments, the fiber web may contain wet and dry reinforcing additives or resins, including natural polymers (starches, gums), cellulose derivatives (e.g., carboxymethylcellulose, methylcellulose, hemicellulose), synthetic polymers (e.g., phenolic resins, latex, polyamides, polyacrylamides, urea-formaldehyde, melamine-formaldehyde, polyamides), surfactants, coupling agents, crosslinking agents, and/or conductive Additives etc.

The webs described herein can be used in entire filter devices or filter elements. In some embodiments, a fiber web comprises at least a first layer and a second layer, wherein at least one of the layers comprises fibrillated fibers. In some embodiments, one or more additional layers or components are included within the web (eg, disposed adjacent to, in contact with one or both sides of the web). In some cases, the one or more additional layers may be formed primarily or entirely of non-fibrillated fibers, but in other embodiments may include fibrillated fibers. Non-limiting examples of additional layers include meltblown layers, wetlaid layers, coarse fiber electret media, spunbond layers, or electrospun layers. In some embodiments, a plurality of webs comprising primarily fibrillated fibers and non-fibrillated fibers according to embodiments described herein may be laminated together in forming a multilayer sheet for a filter media or element .

As noted above, in some embodiments, two or more layers of a web may be formed separately and then combined by any suitable method (eg, lamination, sequencing) or through the use of an adhesive. The two or more layers may be formed using different processes or the same process. For example, each layer can be independently formed by a wet-laid process, a non-wet-laid process (eg, a dry-laid process, a spinning process, a meltblown process), or any other suitable method. In certain embodiments, wet-laid or non-wet-laid layers may be formed directly on a scrim or other suitable substrate.

In some embodiments, two or more layers can be formed by the same process (e.g., a wet-laid process, or a non-wet-laid process (e.g., a dry-laid process, a spinning process, a meltblown process, or any other suitable process). In some cases, the two or more layers may be formed simultaneously. In some embodiments, there may be at least one feature gradient.

In embodiments where the web comprises a meltblown layer, the meltblown layer may have commonly-owned U.S. Patent Publication No. 2009/0120048 based on U.S. Patent Application Serial No. 12/266,892, filed May 14, 2009. One or more of the features described in commonly-owned U.S. Application Serial No. 12/971,539, entitled "Meltblown Filter Medium," and filed December 17, 2010, and entitled "Fine Fiber Filter Media and Processes," each of which One is hereby incorporated by reference in its entirety for all purposes.

The different layers can be adhered together by suitable methods. For example, the layers may be adhered to each other by adhesives and/or fusion bonded to each other on either side. Lamination and calendering processes may also be used. In some embodiments, additional layers may be formed from any type of fiber or blend of fibers via an additional headbox or coater and suitably adhered to another layer.

The fiber web (and resulting filter media) can have various desirable properties and characteristics described in the following paragraphs.

The basis weight of the fiber web can vary depending on factors such as the strength requirements of a given filtration application, the materials used to form the filter media, and the desired level of filtration efficiency and allowable levels of resistance or pressure drop. In certain embodiments described herein, some webs may have a low basis weight but achieve favorable filtration performance or mechanical properties. For example, webs that incorporate fibrillated fibers (which provide increased surface area to the web) can have a lower basis weight without sacrificing strength.

The weight per unit area of the fiber web can usually be selected according to needs. In some embodiments, the fiber web may have a basis weight of about 5 g/m ² to about 1000 g/m ² . For example, the basis weight of the fiber web can be about 15 g/m ² to about 400 g/m ² , about 30 g/m ² to about 300 g/m ² , about 50 g/m ² to about 200 g/m ² , about 90 g/m 2 ² to about 200 g/m ² , about 90 g/m ² to about 150 g/m ² . In some embodiments, the fiber web may have a basis weight greater than or equal to about 5 g/m ² (e.g., greater than or equal to about 10 g/m ² , greater than or equal to about 40 g/m ² , greater than or equal to about 75 g/m 2 ² , greater than or equal to about 100g/m ² , greater than or equal to about 150g/m ² , greater than or equal to about 200g/m ² , greater than or equal to about 250g/m ² , greater than or equal to about 300g/m ² , greater than or equal to about 350 g/m ² , or greater than or equal to about 400 g/m ² ). In some cases, the fiber web may have a basis weight less than or equal to about 1000 g/m ² (e.g., less than or equal to about 700 g/m ² , less than or equal to about 500 g/m ² , less than or equal to about 400 g/m ² , less than or equal to about 350g/m ² , less than or equal to about 300g/m ² , less than or equal to about 250g/m ² , less than or equal to about 200g/m ² , less than or equal to about 150g/m ² , less than or equal to about 100 g/m ² , less than or equal to about 75 g/m ² , or less than or equal to about 50 g/m ² ). Combinations of the above ranges are also possible (eg, a weight per area greater than about 40 g/m ² and less than or equal to about 400 g/m ² ). Other ranges are also possible. As determined herein, the basis weight of a fiber web is measured according to TAPPI T410 standard. Values are expressed in grams per square centimeter.

As described herein, in some embodiments, the web comprises at least a first layer and a second layer, as illustratively shown in FIG. 1 . In some such embodiments, the first layer may have a basis weight of from about 5 g/m ² to about 1000 g/m ² . For example, the basis weight of the first layer may be greater than or equal to about 8 g/m ² (eg, greater than or equal to about 10 g/m ² , greater than or equal to about 40 g/m ² , greater than or equal to about 65 g/m ² , greater than or equal to or equal to about 75 g/m ² , greater than or equal to about 100 g/m ² , greater than or equal to about 150 g/m ² , greater than or equal to about 200 g/m ² , greater than or equal to about 250 g/m ² , greater than or equal to about 300 g/m 2 m ² , greater than or equal to about 350 g/m ² , greater than or equal to about 400 g/m ² , greater than or equal to about 500 g/m ² , greater than or equal to about 600 g/m ² , greater than or equal to about 700 g/m ² , greater than or equal to equal to about 800 g/m ² , or greater than or equal to about 900 g/m ² ). In some cases, the basis weight of the first layer is less than or equal to about 1000 g/m ² (e.g., less than or equal to about 1000 g/m ² , less than or equal to about 900 g/m ² , less than or equal to about 800 g/m ² , less than or equal to about 700g/m ² , less than or equal to about 600g/m ² , less than or equal to about 500g/m ² , less than or equal to about 400g/m ² , less than or equal to about 350g/m ² , less than or equal to about 300g/m ² , less than or equal to about 250g/m ² , less than or equal to about 200g/m ² , less than or equal to about 165g/m ² , less than or equal to about 150g/m ² , less than or equal to about 100g/m ² , less than or equal to about 75 g/m ² , less than or equal to about 50 g/m ² ). Combinations of the above ranges are also possible (eg, the first layer has a basis weight of greater than about 40 g/m ² and less than or equal to about 350 g/m ² ). Other ranges are also possible.

The basis weight of the second layer may be from about 3 g/m ² to about 1000 g/m ² . For example, the basis weight of the second layer may be greater than or equal to about 3 g/m ² (eg, greater than or equal to about 8 g/m ² , greater than or equal to about 10 g/m ² , greater than or equal to about 15 g/m ² , greater than or equal to or equal to about 20 g/m ² , greater than or equal to about 30 g/m ² , greater than or equal to about 40 g/m ² , greater than or equal to about 45 g/m ² , greater than or equal to about 50 g/m ² , greater than or equal to about 75 g/m 2 m ² , greater than or equal to about 100 g/m ² , greater than or equal to about 150 g/m ² , greater than or equal to about 200 g/m ² , greater than or equal to about 250 g/m ² , greater than or equal to about 300 g/m ² , greater than or equal to Equal to about 350g/m ² , greater than or equal to about 400g/m ² , greater than or equal to about 500g/m ² , greater than or equal to about 600g/m ² , greater than or equal to about 700g/m ² , greater than or equal to about 800g/m ² , or greater than or equal to about 900 g/m ² ). In some cases, the second layer has a basis weight of less than or equal to about 1000 g/m ² , less than or equal to about 900 g/m ² , less than or equal to about 800 g/m ² , less than or equal to about 700 g/m ² , less than or equal to or equal to about 600g/m ² , less than or equal to about 500g/m ² , less than or equal to about 400g/m ² , less than or equal to about 350g/m ² , less than or equal to about 300g/m ² , less than or equal to about 250g/m 2 m ² , less than or equal to about 200 g/m ² , less than or equal to about 165 g/m ² , less than or equal to about 150 g/m ² , less than or equal to about 100 g/m ² , less than or equal to about 75 g/m ² (for example, Less than or equal to about 50g/m ² , less than or equal to about 45g/m ² , less than or equal to about 40g/m ² , less than or equal to about 35g/m ² , less than or equal to about 30g/m ² , less than or equal to about 25g /m ² , less than or equal to about 20 g/m ² , less than or equal to about 15 g/m ² , less than or equal to about 10 g/m ² , or less than or equal to about 5 g/m ² ). Combinations of the above ranges are also possible (eg, the second layer has a basis weight of greater than about 3 g/m ² and less than or equal to about 50 g/m ² ). Other ranges are also possible.

In some embodiments, the basis weights of the first layer and the second layer can be selected to achieve a particular basis weight ratio. For example, the basis weight ratio of the first layer to the second layer (e.g., the basis weight of the first layer:the basis weight of the second layer) can be at least 1:1, at least 2:1, at least 3:1, At least 5:1, at least 6:1, at least 10:1, at least 15:1, or at least 20:1. In some embodiments, the basis weight ratio of the first layer to the second layer is less than 20:1, less than 15:1, less than 14:1, less than 10:1, less than 6:1, less than 5:1, less than 4:1, less than 3:1, less than 2:1. Combinations of the above ranges are also possible (eg, a basis weight ratio of at least 3:1 and less than 5:1). Other ranges are also possible.

In other embodiments, the ratio of the basis weight of the second layer to the first layer (e.g., the basis weight of the second layer:the basis weight of the first layer) can be at least 1:1, at least 2:1, At least 3:1, at least 5:1, at least 6:1, at least 10:1, at least 15:1, or at least 20:1. In some embodiments, the basis weight ratio of the first layer to the second layer is less than 20:1, less than 15:1, less than 14:1, less than 10:1, less than 6:1, less than 5:1, less than 4:1, less than 3:1, less than 2:1. Combinations of the above ranges are also possible (eg, a basis weight ratio of at least 3:1 and less than 5:1).

In embodiments where additional layers (eg, third layers, fourth layers, etc.) are included in the web, the additional layers may have a basis weight of from about 5 g/m ² to about 800 g/m ² . For example, the additional layer may have a basis weight greater than or equal to about 5 g/m ² (e.g., greater than or equal to about 10 g/m ² , greater than or equal to about 40 g/m ² , greater than or equal to about 65 g/m ² , greater than or equal to Equal to about 75g/m ² , greater than or equal to about 100g/m ² , greater than or equal to about 150g/m ² , greater than or equal to about 200g/m ² , greater than or equal to about 250g/m ² , greater than or equal to about 300g/m ² , greater than or equal to about 400g/m ² , greater than or equal to about 500g/m ² , greater than or equal to about 600g/m ² , greater than or equal to about 700g/m ² ). In some cases, the additional layer has a basis weight of about 800 g/m ² or less (e.g., about 700 g/m ² or less, about 600 g/m ² or less, about 500 g/m ² or less, Less than or equal to about 400g/m ² , less than or equal to about 300g/m ² , less than or equal to about 250g/m ² , less than or equal to about 200g/m ² , less than or equal to about 165g/m ² , less than or equal to about 150g /m ² , less than or equal to about 100 g/m ² , less than or equal to about 75 g/m ² , less than or equal to about 50 g/m ² ). Combinations of the above ranges are also possible (eg, the additional layer has a basis weight of greater than about 5 g/m ² and less than or equal to about 100 g/m ² ). Other ranges are also possible.

In certain embodiments, the fiber webs described herein can have a relatively high surface area. In certain embodiments, the fiber web may have a surface area from about 0.1 m ² /g to about 100 m ² /g. In some cases, the fiber web has a surface area of about 0.1 m ² /g or greater, about 1 m ² /g or greater, about 1.5 m ² /g or greater, about 2.0 m ² /g or greater, about 2.5m ² /g or more, about 3m ² /g or more, about 5m ² /g or more, about 10m ² /g or more, about 20m ² /g or more, about 30m ² /g or greater, about 40 m ² /g or greater, about 50 m ² /g or greater, about 60 m ² /g or greater, about 70 m ² /g or greater, about 80 m ² /g or greater, or About 90m ² /g or more. In some embodiments, the fiber web has a surface area of about 100 m ² /g or less, about 90 m ² /g or less, about 80 m ² /g or less, about 70 m ² /g or less, about 60 m ² /g or less, about 50m ² /g or less, about 40m ² /g or less, about 30m ² /g or less, about 20m ² /g or less, about 10m ² /g or less , about 5 m ² /g or less, or about 2 m ² /g or less. Combinations of the above ranges are also possible (eg, surface areas of about 100 m ² /g or less and about 10 m ² /g or greater). Other ranges are also possible.

In some embodiments, a layer (eg, the first layer and/or the second layer) can have a surface area within one or more of the ranges described above.

As described herein, surface area is measured by using standard BET surface area measurement techniques. The BET surface area is measured according to Part 10 of the International Battery Association standard BCIS-03A, "Recommended Battery Materials Specifications Valve Regulated Recombinant Batteries", and Part 10 is "Standard Test Method for Surface Area of Recombinant Battery Separator Mat". According to this technique, BET surface area is measured via absorption analysis using nitrogen gas using a BET surface area analyzer (e.g., Micromeritics Gemini III 2375 surface area analyzer); sample size is 0.5 to 0.6 grams in a 3/4" tube; and, the sample is allowed to Degas at 75°C for a minimum of 3 hours.

Thickness as referred to herein is determined according to standard TAPPI T411. The thickness of the fiber web may be from about 0.3 mm to about 10 mm. In some embodiments, the thickness of the fiber web can be greater than or equal to about 0.3 mm, greater than or equal to about 0.5 mm, greater than or equal to about 0.6 mm, greater than or equal to about 0.8 mm, greater than or equal to about 1.0 mm, greater than or equal to About 1.2mm, greater than or equal to about 1.5mm, greater than or equal to about 2mm, greater than or equal to about 3mm, greater than or equal to about 4mm, greater than or equal to about 5mm, or greater than or equal to about 7mm. In certain embodiments, the fiber web may have a thickness of about 10 mm or less, about 7 mm or less, about 5 mm or less, about 4 mm or less, about 2 mm or less, about 1.2 mm or less, Less than or equal to about 1.0 mm, less than or equal to about 0.8 mm, less than or equal to about 0.6 mm, or less than or equal to about 0.4 mm, less than or equal to about 0.2 mm. Combinations of the above ranges are also possible (eg, a thickness greater than about 0.3 mm and less than or equal to about 1.0 mm). Other ranges are also possible.

In some embodiments, a layer (eg, first layer and/or second layer) can have a thickness within one or more of the ranges described above for the entire web.

The fiber web exhibits a suitable mean flow pore size. As described herein, mean flow pore size is measured according to standard ASTM F316. In some embodiments, the mean flow pore size can be from about 0.1 microns to about 50 microns (e.g., from about 0.1 microns to about 5 microns, from about 5 microns to about 40 microns, from about 15 microns to about 40 microns, or from about 25 microns to about 40 microns. about 40 microns). In some embodiments, the fiber web may have a mean flow pore size of about 50 microns or less, about 45 microns or less, about 40 microns or less, about 30 microns or less, about 25 microns or less, or about 25 microns or less. or equal to about 20 microns, less than or equal to about 15 microns, less than or equal to about 10 microns, or less than or equal to about 5 microns, less than or equal to about 3 microns, less than or equal to about 2 microns, less than or equal to about 1 micron, less than or about 0.8 microns, less than or equal to about 0.5 microns, or less than or equal to about 0.2 microns. In other embodiments, the mean flow pore size may be greater than or equal to about 0.1 micron, greater than or equal to about 0.2 micron, greater than or equal to about 0.5 micron, greater than or equal to about 0.8 micron, greater than or equal to about 1 micron, greater than or equal to About 2 microns, greater than or equal to about 5 microns, greater than or equal to about 10 microns, greater than or equal to about 15 microns, greater than or equal to about 20 microns, greater than or equal to about 25 microns, greater than or equal to about 30 microns, greater than or equal to about 35 microns, greater than or equal to about 45 microns, or greater than or equal to about 50 microns. Combinations of the above ranges are also possible (eg, a mean flow pore size of greater than or equal to about 10 microns and less than or equal to about 50 microns). Other values and ranges of mean flow pore size are also possible.

In some embodiments, it may be preferable for the web to exhibit certain mechanical properties. For example, as noted above, a fiber web comprising primarily fibrillated synthetic fibers and non-fibrillated synthetic fibers (e.g., a web with limited or no glass fibers) can produce a relatively flexible and strong filter media, It does not include the environmental concerns associated with conventional glass fibers in filter media. In some embodiments, fiber webs described herein having few to no glass fibers may exhibit greater degrees of elongation, burst strength, and/or relative to fiber webs having relatively more glass fibers incorporated therein. or tensile strength.

In some embodiments, the tensile elongation in the machine machine direction of the web can be greater than about 0.2%, greater than about 0.5%, greater than about 0.8%, greater than about 2%, greater than about 5%, greater than about 8%, greater than about 10%, and/or less than or equal to about 12%. For example, the tensile elongation in the machine machine direction of the web can be from about 0.2% to about 4.0%, from about 0.2% to about 3.0%, from about 0.5% to about 3.5%, from about 0.5% to about 2.0%, from about 1.0% to About 3.0%, about 1.5% to about 2.5%, or about 0.2% to about 12%. In some embodiments, the tensile elongation in the machine direction of the web can be greater than about 0.2%, greater than about 0.5%, greater than about 0.8%, or greater than about 1.0%, greater than about 2%, greater than about 5%, greater than About 8%, greater than about 10%, and/or less than or equal to about 12%. For example, the tensile elongation in the machine direction of the web can be from about 0.2% to about 6.0%, from about 0.2% to about 5.0%, from about 0.2% to about 4.0%, from about 0.5% to about 4.5%, from about 1.0% to About 3.5%, about 1.0% to about 3.0%, about 2.0% to about 3.5%, or about 0.2% to about 12%. In some cases, a web exhibiting an increased degree of elongation may also be more pleatable, for example, by exhibiting an overall reduction in potential damage that may occur at the edges of the filter media.

The tensile strength of the filter media in the machine direction can be greater than about 2N/15mm, greater than about 4N/15mm, greater than about 6N/15mm, greater than about 10N/15mm, greater than about 20N/15mm, greater than about 50N/15mm, greater than about 75N /15mm, greater than about 100N/15mm, greater than about 125N/15mm, greater than about 150N/15mm, or greater than about 175N/15mm, and/or less than or equal to about 200N/15mm. For example, the tensile strength of the fiber web in the machine direction can be from about 3 N/15mm to about 20N/15mm, from about 1N/15mm to about 6N/15mm, from about 10N/15mm to about 20N/15mm, from about 1N/15mm to about 200N /15mm, or about 100N/15mm to about 200N/15mm. The tensile strength of the web in the cross machine direction may be greater than about 1 N/15mm, greater than about 3N/15mm, greater than about 4N/15mm, greater than about 6N/15mm, greater than about 10N/15mm, greater than about 20N/15mm, greater than about 50N /15mm, greater than about 75N/15mm, greater than about 100N/15mm, greater than about 125N/15mm, greater than about 150N/15mm, or greater than about 175N/15mm, and/or less than or equal to about 200N/15mm. In some cases, the tensile strength of the web in the cross machine direction may be from about 1 N/15mm to about 6 N/15mm, from about 2N/15mm to about 10N/15mm, or from about 3N/15mm to about 9N/15mm, from about 1N/15mm. 15mm to about 200N/15mm, or about 100N/15mm to about 200N/15mm. In some cases, the cross-machine tensile strength can be greater than or less than the machine-machine tensile strength.

Tensile strength and tensile elongation are measured according to standard TAPPI T494.

The Mullen burst test can be used as a further test to measure the strength required to pierce a web under certain conditions as an indication of the load-bearing capacity of the web. Mullen burst strength is measured according to standard TAPPI T403. In some embodiments, the fiber web may have a Mullen burst strength of greater than 10 psi, greater than 15 psi, greater than 30 psi, greater than 40 psi, greater than 60 psi, greater than 75 psi, or from about 5 psi to about 120 psi, from about 5 psi to about 50 psi, or from about 30 psi to About 100psi.

The webs described herein may also exhibit beneficial filtration performance characteristics such as dust holding capacity (DHC), efficiency, air permeability, and the like.

The fiber webs described herein can have beneficial dust holding capacity properties. In some embodiments, the DHC of the fiber web can be from about 80 g/m ² to about 300 g/m ² . In some embodiments, the DHC may be greater than or equal to about 80 g/m ² , greater than or equal to about 100 g/m ² , greater than or equal to about 125 g/m ² , greater than or equal to about 150 g/m ² , greater than or equal to about 175 g /m ² , greater than or equal to about 200 g/m ² , greater than or equal to about 225 g/m ² , greater than or equal to about 250 g/m ² , greater than or equal to about 275 g/m ² , greater than or equal to about 300 g/m ² , or Greater than or equal to about 350 g/m ² . In some cases, the DHC may be less than or equal to about 400 g/m ² , less than or equal to about 350 g/m ² , less than or equal to about 300 g/m ² , less than or equal to about 275 g/m ² , less than or equal to about 250 g/m 2 m ² , less than or equal to about 225 g/m ² , less than or equal to about 200 g/m ² , less than or equal to about 175 g/m ² , less than or equal to about 150 g/m ² , less than or equal to about 125 g/m ² , or less than Or equal to about 100 g/m ² . Combinations of the above ranges are also possible (eg, greater than about 150 g/m ² and less than or equal to about 300 g/m ² of DHC). Other ranges are also possible.

The dust holding capacity as referred to herein is based on the multipass filtration test according to the ISO 16889/19438 procedure (corrected by testing flat sheet samples) on a multipass filtration test rig manufactured by FTI. The test can be performed under different conditions. The test used ISO A3 Medium test dust manufactured by PTI, Inc. at a base upstream gravimetric dust level (BUGL) of 10 mg/liter to 50 mg/liter. The test fluid was aviation hydraulic fluid AERO HFA MIL H-5606A manufactured by Mobil. The test is performed at a face velocity of 0.06 cm/sec to 0.16 cm/sec until an end pressure of 1 to 2 (100 kPa to 200 kPa). Unless otherwise specified, dust holding capacity values (and/or efficiency values) stated herein are determined at a BUGL of 25 mg/L, a face velocity of 0.06 cm/second, and a terminal pressure of 100 kPa.

Efficiency of filtration (eg, liquid filtration efficiency) and initial efficiency (eg, initial liquid filtration efficiency) of different particle sizes can be measured using the multi-pass filtration test described above. Particles having a size such as: about 50 microns or more, about 30 microns or more, about 20 microns or more, about 15 microns or more, about 10 microns or more, can be filtered using a suitable fiber web , greater than or equal to about 5 microns, greater than or equal to about 4 microns, greater than or equal to about 3 microns, or greater than or equal to about 1 micron. The smallest particle size x selected upstream and downstream of the media can be taken at ten points that equally divide the test time (for example, where x is 1 micron, 2 micron, 3 micron, 4 micron, 5 micron, 7 micron , 10 microns, 15 microns, 20 microns, 25 microns, 30 microns, 40 microns, or 50 microns) of particle counts (particles/ml). Typically, particle size x means that particles of x microns or larger will be captured by the layer or medium. An average of upstream and downstream particle counts can be taken at a respective selected minimum particle size and particles larger than that size. According to the average number of particles in the upstream (injection, C ₀ ) and the average number of particles in the downstream (passing, C), the liquid filtration efficiency test values for the respective selected minimum particle sizes can be obtained by the relationship [(1-[C/C0 ])*100%] OK. As described herein, efficiency can be measured according to the standard ISO 16889/19438 procedure. A similar protocol can be used to measure initial efficiency, which refers to the average efficiency measurements of the medium at 4 minutes, 5 minutes, and 6 minutes after running the test. Efficiency and initial efficiency measurements stated herein refer to values where x = 4 microns unless otherwise indicated.

The fiber webs described herein can have a wide range of efficiencies (eg, liquid filtration efficiencies). In some embodiments, the efficiency of the fiber web is from about 90% to about 100%. The efficiency can be, for example, greater than or equal to about 90%, greater than or equal to about 92%, greater than or equal to about 94%, greater than or equal to about 96%, greater than or equal to about 98%, greater than or equal to about 99%, greater than or equal to Equal to about 99.4%, greater than or equal to about 99.5%, greater than or equal to about 99.7%, greater than or equal to about 99.8%, greater than or equal to about 99.9%, or greater than or equal to about 99.99%. Such efficiencies can be achieved to filter particles of different sizes such as: 10 microns or larger, 8 microns or larger, 6 microns or larger, 5 microns or larger, 4 microns or larger Large particles, particles 3 microns or larger, particles 2 microns or larger, or particles 1 micron or larger. Other particle sizes and efficiencies are also possible.

The above efficiency values apply to single-layer arrangements as well as to arrangements consisting of multiple layers. For example, a combined filtration arrangement comprising a first layer and a second layer, wherein one of the layers comprises at least one fibrillated fiber, may in some embodiments be sensitive to particles of 4 microns or larger, in other implementations. 3 microns or larger particles in the scheme, 2 microns or larger particles in still other embodiments, or 1 micron or larger particles in still other embodiments exhibit the following efficiencies: greater than or equal to about 90%, greater than or equal to about 92%, greater than or equal to about 94%, greater than or equal to about 96%, greater than or equal to about 98%, greater than or equal to about 99%, greater than or equal to about 99.4%, greater than or equal to about 99.5 %, greater than or equal to about 99.7%, greater than or equal to about 99.8%, greater than or equal to about 99.9%, or greater than or equal to about 99.99%.

In some embodiments, a layer (eg, a first layer, a second layer, and/or an additional layer) can have an efficiency within one or more of the ranges described above.

In addition, the fiber web can have a suitable initial efficiency. In some embodiments, the initial efficiency may be from about 30% to about 99.999% (eg, from about 60% to about 99.9%). For example, in certain embodiments, the initial efficiency can be at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, At least about 95%, at least about 98%, at least about 99%, at least about 99.9%. Other ranges are also possible.

In some embodiments, a layer (eg, a first layer, a second layer, and/or an additional layer) can have an initial efficiency within one or more of the ranges described above.

In certain embodiments, fiber webs can be configured to achieve high fuel-water separation efficiencies, eg, for separating water from fuel-water emulsions. In some embodiments, the fuel-water separation efficiency may be from about 30% to about 99.999% (eg, from about 60% to about 99.9%). For example, in certain embodiments, the fuel-water separation efficiency can be at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90%, at least about 95%, at least about 98%, at least about 99%, at least about 99.9%. Other ranges are also possible.

As used herein, fuel-water separation efficiency is measured using the SAE J1488 test. The test involved passing a fuel (ultra-low sulfur diesel fuel) with a controlled water content (2500 ppm) through the medium by a pump at a face velocity of 0.069 cm/sec. The water is emulsified into fine droplets and challenged to the medium. The water coalesces or sheds or both and collects at the bottom of the housing. The water content was measured both upstream and downstream of the medium by Karl Fischer titration. The efficiency is the amount of water removed from the fuel-water mixture. The fuel-water separation efficiency is calculated as (1-C/2500)*100, where C is the downstream water concentration.

Generally, the media can be classified as coalesced or exfoliated based on the amount of water collected. If the water is collected further upstream, the media is predominantly exfoliated. If the water is collected further downstream, the medium is predominantly coalesced. Combinations of the above can also occur where the media can be both coalesced and exfoliated.

The fiber web can exhibit suitable air permeability characteristics. In some embodiments, the air permeability may be from about 0.1 cubic feet per minute per square foot (cfm/sf) to about 250 cfm/sf (e.g., from about 0.5 cfm/sf to about 50 cfm/sf, from about 50 cfm/sf to about 125 cfm/sf, about 5 cfm/sf to about 150 cfm/sf, about 10 cfm/sf to about 150 cfm/sf, or about 50 cfm/sf to about 150 cfm/sf). In some embodiments, the air permeability can be greater than or equal to about 0.5 cfm/sf, greater than or equal to about 2 cfm/sf, greater than or equal to about 5 cfm/sf, greater than or equal to about 10 cfm/sf, greater than or equal to about 25 cfm /sf, greater than or equal to about 50 cfm/sf, greater than or equal to about 75 cfm/sf, greater than or equal to about 100 cfm/sf, greater than or equal to about 150 cfm/sf, greater than or equal to about 200 cfm/sf, or greater than or equal to about 250 cfm/sf sf. In certain embodiments, the air permeability may be less than or equal to about 250 cfm/sf, less than or equal to about 200 cfm/sf, less than or equal to about 175 cfm/sf, less than or equal to about 150 cfm/sf, less than or equal to about 125 cfm /sf, less than or equal to about 100 cfm/sf, less than or equal to about 75 cfm/sf, less than or equal to about 50 cfm/sf, less than or equal to about 25 cfm/sf, or less than or equal to about 5 cfm/sf. Combinations of the above ranges are also possible (eg, an air permeability of greater than or equal to about 5 cfm/sf and less than or equal to about 200 cfm/sf). Other ranges are also possible.

As described herein, the permeability is measured according to standard TAPPI T-251. The permeability is an inverse function of flow resistance and can be measured with a Frazier permeability tester (eg, TexTest Instrument, FX 3300). The Frazier Permeability Tester measures the volume of air passing through a unit area of a sample per unit time under a fixed differential pressure across the sample. Air permeability can be expressed in cubic feet per minute per square foot at 0.5 inches of water.

In some embodiments, a layer (eg, the first layer and/or the second layer) can have a permeability within one or more of the ranges described above.

In some embodiments, the additional layers of the web (e.g., third layer, fourth layer, etc.) may have an air permeability of about 0.5 cubic feet per minute per square foot (cfm/sf) to about 1500 cfm/sf (e.g., about 0.5 cfm/sf to about 70 cfm/sf, about 5 cfm/sf to about 700 cfm/sf, or about 5 cfm/sf to about 1300 cfm/sf). In some embodiments, the air permeability can be greater than or equal to about 0.5 cfm/sf, greater than or equal to about 5 cfm/sf, greater than or equal to about 10 cfm/sf, greater than or equal to about 50 cfm/sf, greater than or equal to about 70 cfm /sf, greater than or equal to about 100 cfm/sf, greater than or equal to about 300 cfm/sf, greater than or equal to about 500 cfm/sf, greater than or equal to about 700 cfm/sf, or greater than or equal to about 1000 cfm/sf. In certain embodiments, the air permeability may be less than or equal to about 1500 cfm/sf, less than or equal to about 1300 cfm/sf, less than or equal to about 1000 cfm/sf, less than or equal to about 800 cfm/sf, less than or equal to about 400 cfm /sf, less than or equal to about 100 cfm/sf, or less than or equal to about 50 cfm/sf. Combinations of the above ranges are also possible. Other ranges are also possible.

In some embodiments, the fiber webs described herein can have a certain relationship between mean flow pore size and permeability. The relationship between the average flow pore diameter and permeability can be expressed as [average flow pore diameter (μm)/(permeability (cfm/sf)) ^0.5 ], which is also referred to herein as the permeability pore index (Perm.Pore Index ). That is, the mean flow pore size of a fibrous media can be divided by the square root of the permeability of the media. In general, all other factors being equal, webs with higher efficiencies can have lower values of [Mean Flow Pore Size (μm)/(Permeability (cfm/sf)) ^0.5 ].

In some embodiments, the fiber webs described herein have a [Mean Flow Pore Size (μm)/(Permeability (cfm/sf)) ^0.5 ] value of from about 0.5 to about 3.0. In some embodiments, the [mean flow pore size (μm)/(permeability (cfm/sf)) ^0.5 ] value of the fiber web is less than or equal to about 3, less than or equal to about 2.5, less than or equal to about 2, less than or equal to Equal to about 1.8, less than or equal to about 1.6, less than or equal to about 1.5, less than or equal to about 1.4, less than or equal to about 1.2, less than or equal to about 1.0, less than or equal to about 0.9, less than or equal to about 0.8, less than or equal to about 0.7, or less than or equal to about 0.6. In some embodiments, the fiber web has a value of [mean flow pore size (μm)/(permeability (cfm/sf)) ^0.5 ] greater than or equal to about 0.5, greater than or equal to about 0.6, greater than or equal to about 0.8, greater than or equal to About 1.0, greater than or equal to about 1.2, greater than or equal to about 1.5, or greater than or equal to about 2.0. Combinations of the above ranges are also possible (eg, values of [Mean Flow Pore Size (μm)/(Permeability (cfm/sf)) ^0.5 ] greater than about 0.5 and less than or equal to about 1.5). Other ranges are also possible.

In some embodiments, a layer (eg, first layer and/or second layer) may have [mean flow pore size (μm)/(permeability (cfm/sf)) ^0.5 within one or more of the above ranges ]value.

It should be understood that while the above parameters and characteristics are described with respect to fiber webs, the same parameters and characteristics, including values and ranges for these parameters and characteristics, can also be used for filter media.

The fiber webs described herein can be produced using suitable methods, such as using a wet-laid process or a non-wet-laid process (e.g., a dry-laid process, a spinning process, a melt-blown process, or any other suitable method). Typically, the wet-laying process involves blending together one or more types of web; for example, combining non-fibrillated fibers (e.g., monocomponent and/or bicomponent fibers) with fibrillated fibers or any other components (eg, other types of synthetic fibers) are mixed together to provide a fiber slurry. In certain embodiments, only fibrillated fibers are included in the slurry. In some embodiments, the fibrillated fibers are of one type but have different levels of fibrillation. The slurry can be, for example, a water-based slurry. In certain embodiments, fibrillated fibers, optional non-fibrillated fibers, and any other suitable fibers are optionally separated prior to being mixed together (e.g., to obtain a greater degree of uniformity in the mixture) Stored or combined in different storage tanks.

For example, first fibers (e.g., fibrillated fibers or non-fibrillated fibers) can be mixed and pulped together in one vessel, and second fibers (e.g., fibrillated fibers) can be mixed together in a separate vessel. Blend and pulp. The first fiber and the second fiber can then be combined together to form a single fiber mixture. Suitable fibers may be processed through a pulper before and/or after mixing together. In some embodiments, a composition of fibers, such as non-fibrillated fibers, fibrillated fibers, and/or other synthetic fibers, is processed through a pulper and/or storage tank prior to being mixed together. It should be understood that other components may also be incorporated into the mixture. Additionally, it should be understood that other fiber type compositions, such as the fiber types described herein, may be used in the fiber mixture.

In certain embodiments, two or more layers are formed by a wet-laying process. For example, a first dispersion (e.g., a slurry) comprising fibers in a solvent (e.g., an aqueous solvent such as water) can be applied to a wire conveyor of a paper machine (e.g., a fourdrinier or rotary forming paper machine) to form a The first layer of the mesh conveyor belt load. A second dispersion (eg, another slurry) comprising fibers in a solvent (eg, an aqueous solvent such as water) is applied to the first layer simultaneously with or after depositing the first layer on the web. Vacuum is continuously applied to the first and second dispersions of fibers during the above process to remove solvent from the fibers, thereby producing an article comprising the first and second layers. The article thus formed is then dried and, if necessary, further processed (eg, calendered) using known methods to form a multilayer web. In some embodiments, such treatment can produce a gradient of at least one property across the thickness of the two or more layers.

Any suitable method may be used for generating the slurry. In some embodiments, additional additives may be added to the slurry to facilitate processing. The temperature can also be adjusted to a suitable range, eg, 33°F to 100°F (eg, 50°F to 85°F). In some cases, the temperature of the slurry is maintained. In some cases, the temperature is not actively adjusted.

In some embodiments, the wet-laying process uses equipment similar to conventional papermaking processes, eg, hydropulpers, formers or headboxes, dryers, and optional converters. In some cases, webs were also made from experimental handsheet molds. As mentioned above, the stock can be prepared in one or more pulpers. After the slurry has been properly mixed in the pulper, the slurry may be pumped into a headbox where it may or may not be combined with other slurries. Other additives may or may not be added. The slurry may also be diluted with additional water to achieve a final concentration of fibers within an appropriate range, for example, from about 0.1% to about 0.5% by weight.

Wet-laying processes may be particularly useful for forming gradients of one or more properties in webs such as those described herein. For example, in some cases the same slurry is pumped into separate headboxes to form different layers and/or gradients in the web. In other cases, two or more different slurries may be pumped into separate headboxes to form different layers and/or gradients in the web. For experimental samples, a first layer can be formed from fiber slurry, which is drained and dried, then a second layer can be formed from fiber slurry on top. In other embodiments, a first layer may be formed and a second layer may be formed on top, drained and dried.

In some cases, the pH of the fiber slurry can be adjusted as desired. For example, the fibers of a slurry are generally dispersible under neutral conditions.

The stock may optionally be passed through a centrifugal cleaner and/or pressure screen to remove non-fiberized material before the stock is sent to the headbox. The slurry may or may not be passed through additional equipment, such as a refiner or deflaker, to further enhance dispersion or fibrillation of the fibers. For example, a deflaker may be used to smooth or remove the fiber at any point during slurry formation. Lumps or protrusions that appear. Fibers can then be collected onto a screen or wire at an appropriate rate using any suitable equipment (e.g., Fourdrinier, Rotary Forming, Rotary, or Inclined Fourdrinier) .

In some embodiments, the process includes introducing a binder (and/or other components) into a preformed fiber layer (eg, comprising fibrillated fibers and non-fibrillated fibers). In some embodiments, the different components contained in the binder, which may be individually in emulsion form, are added to the fibrous layer using suitable techniques while passing the fibrous layer along a suitable screen or mesh. In some cases, the various components of the binder resin are mixed into an emulsion prior to combination with other components and/or fibrous layers. In some embodiments, the components contained in the binder resin may be pulled through the fibrous layer using, for example, gravity and/or vacuum. In some embodiments, one or more components contained in the binder may be diluted with demineralized water and pumped to the fibrous layer. In some embodiments, the binder may be introduced to the fibrous layer by spraying onto the formed media or by any other suitable method (eg, size press coating, foam saturation, curtain coating, rod coating, etc.). In some embodiments, a binder material may be applied to the fiber slurry prior to introducing the fiber slurry into the headbox. For example, a binder material may be introduced (eg, infused) into the fiber slurry and impregnate and/or settle onto the fibers. In some embodiments, the binder resin can be added to the web by a solvent saturation process as described in more detail herein.

In other embodiments, one or more layers of the web are formed using a non-wet-laid process. In certain embodiments, the non-wet-laid process includes a dry-laid process, such as a carding process. In some embodiments, an airlaid process is used. For example, in an air-laying process, non-fibrillated synthetic fibers may be mixed with fibrillated fibers (eg, lyocell fibers) while air is blown onto a conveyor belt, followed by application of a binder. In some embodiments, in the carding process, fibers are manipulated through a roller and extensions (eg, hooks, needles) attached to the roller prior to application of the binder. In some cases, forming a web by a non-wet-laid process may be more suitable for creating a highly porous media.

As described herein, the first layer and/or the second layer of the web can be formed by a non-wet-laid process. In some embodiments, the first layer and/or the second layer may be impregnated (eg, by saturation, spraying, etc.) with any suitable binder resin, as described above.

During or after web formation, the web may be further processed according to various known techniques. Optionally, additional layers may be formed and/or added to the web using processes such as lamination, co-pleating, or sequencing. For example, in some cases, two layers are formed into a composite article by a wet-laid process as described above, and the composite article is then combined with a third layer by any suitable process (e.g., lamination, co-pleating, or sequencing). layer combination. It will be appreciated that the methods described herein may be modified not only based on the composition of the individual fibrous layers but also on the effect of using multiple fibrous layers that alter the appropriate combination of properties to form a web having the features described herein. Fiber webs or composite articles formed by the process described in .

In some embodiments, further processing can include pleating the web. For example, two layers may be joined by a co-pleating process. In some cases, the web or its individual layers may be pleated by forming score lines at appropriate spacing from one another, allowing the web to fold. It should be understood that any suitable pleating technique may be used.

In some embodiments, the fiber web may be post-treated, eg, subjected to a creping treatment, to increase the internal surface area of the web. In embodiments where the web is pleated or corrugated, the depth of the pleats or corrugations can vary from about 0.01 mm to about 7 mm. For example, the depth of the folds or wrinkles can be at least about 0.01 mm, at least about 0.1 mm, at least about 1 mm, at least about 2 mm, or at least about 5 mm, and/or less than or equal to about 7 mm, less than or equal to about 5 mm, less than or equal to about 3 mm, or less than or equal to about 1 mm. Combinations of the above ranges are also possible. Other ranges are also possible. The periodicity of the pleats or wrinkles can also vary, for example, from about 2 cycles/inch to about 8 cycles/inch.

In other embodiments, the web may be embossed or otherwise creased to create protrusions and/or indentations in the web. In such embodiments, the depth of the protrusions or indentations may vary from about 0.01 mm to about 7 mm. For example, the depth of the protrusion or indentation can be at least about 0.01mm, at least about 0.1mm, at least about 1mm, at least about 2mm, or at least about 5mm, and/or less than or equal to about 7mm, less than or equal to about 5mm, less than or equal to Equal to about 3 mm, or less than or equal to about 1 mm. Combinations of the above ranges are also possible. Other ranges are also possible.

It should be understood that the fiber web may comprise other components in addition to the one or more layers described herein. In some embodiments, further processing includes incorporating one or more structural features and/or reinforcing elements. For example, fiber meshes may be combined with additional structural features such as polymeric meshes and/or metallic meshes. In some embodiments, a mesh backing can be placed over the web to provide greater stiffness. In some cases, a mesh backing can help maintain the pleated configuration. For example, the screen backing can be an expanded metal mesh or an extruded plastic mesh.

In some embodiments, fiber webs used as filter media can be incorporated into various filter elements for different filtration applications. Exemplary types of filters include hydraulic portable filters, hydraulic industrial filters, fuel filters (eg, automotive fuel filters), oil filters (eg, lube oil filters or heavy duty lube oil filters), chemical Process filters, industrial process filters, medical filters (eg blood filters), air filters and water filters. In some cases, the filter media described herein can be used as coalescer filter media. The filter media may be suitable for filtering gases or liquids.

The fiber webs and filter media disclosed herein can be incorporated into various filter elements for different applications including hydraulic and non-hydraulic filtration applications (including fuel applications, lube oil applications, air applications, etc.). Exemplary uses for hydraulic filters (eg, high pressure filters, medium pressure filters, and low pressure filters) include portable filters and industrial filters.

During use, the web mechanically traps particles on or in the layers as fluid flows through the filter media. The web need not be electrically charged to increase capture of contaminants. Thus, in some embodiments, the filter media is uncharged. However, in some embodiments, the filter media can be charged.

Example

The following examples are intended to illustrate certain embodiments of the invention, but should not be construed as limiting and not exemplifying the full scope of the invention.

Example 1

This example illustrates a method of making a two-ply web comprising: a first layer comprising cellulose pulp fibers and a second layer comprising fibrillated aramid fibers.

Two-layer handsheets were made using the experimental handsheet mold. The fibers for the first layer were mixed with 1000 mL of water in a blender for 2 minutes. The slurry was placed into a handsheet mold and formed into a web on a wire. Drain and dry the web. The web was then placed back into the handsheet mold, and the second slurry was placed into the handsheet mold and formed on top of the first layer. The resulting web was drained and dried. The resulting web comprises a first layer comprising cellulose pulp and a second layer comprising fibrillated aramid fibers. The amount of material added for the first layer is 18.9g (HP-11 softwood pulp, HBA softwood pulp and Kuralon SPG-056 polyvinyl alcohol fibers in a ratio of [56.5:42.5:1]), added for the second layer The amount of material (100% aramid pulp) was 3.8 g. The Canadian Standard Freeness of the fibrillated aramid fiber is 80 mL on average.

The sample has a permeability of 2.5 CFM, an average flow pore size of 1.1 microns, an average multipass efficiency of 99.7% for particles of 4 microns or larger, a dust holding capacity of 115 g/m ² , and a weight per unit area of 137.5 pounds/ream (lb /ream) (12.5 lb/ream for the second layer and 125 lb/ream for the first layer). Multi-pass filtration tests for efficiency and dust holding capacity were performed according to the ISO 16889/19438 procedure at 10 mg/L Basal Upstream Gravity Level (BUGL), 0.16 cm/sec face velocity, 200 kPa terminal pressure and 1 L/min flow rate . The permeability porosity index value is 0.696.

This example shows that higher efficiencies for 4 microns can be obtained in fibrous media comprising fibrillated fibers in one layer. This example also shows that lower permeability pore indices and higher dust holding capacities can be achieved in such media. This example also shows that such efficiencies and dust holding capacities can be obtained in webs that do not contain any glass fibers.

Example 2

This example shows the manufacture of a wet-laid web comprising: a first blend comprising RoburFlash (cellulose) fibers: HP-11 softwood fibers: PET (0.6d x 5mm) fibers. a layer; and a second layer comprising fibrillated lyocell fibers. Several samples were made varying the level of fibrillation of the fibers in the first layer.

Two-ply webs were produced using a wet-laid papermaking process. The first layer is formed and drained on a fourdrinier machine and the second layer is formed on top using another headbox. The resulting web comprised: a first layer comprising a blend of Robur Flash (cellulose) fibers:HP-11 softwood fibers:PET (0.6d x 5mm) fibers; and a second layer comprising fibrillated lyocell fibers. The average Canadian Standard Freeness of the lyocell fibers in the second layer was 40 mL.

The weight ratio of fibers in the first layer was 1:1:0.46 by weight. The basis weight ratio of the second layer to the first layer varies with the conditions used for refining (fibrillation) of the fibers in the first layer. For each sample, the target basis weight for the combined layers was 60 lbs/ream. Experiment with the following conditions:

a. Sample 1: The second layer: the weight ratio of the first layer per unit area is 1:2, and there is no fibrillated fiber in the first layer.

b. Sample 2: The second layer: the first layer has a weight per unit area ratio of 1:2, with some fibrillated fibers in the first layer. The permeability porosity index value is 2.33.

c. Sample 3: The second layer: the weight ratio of the first layer is 1:5, and there are some fibrillated fibers in the first layer. The permeability porosity index value is 0.94. The above three conditions produced fiber webs with relatively low values of [mean flow pore size (μm)/(permeability (cfm/sf)) ^0.5 ] in the range of 1 to 3.

This example also shows that the desired permeability porosity index can be obtained in a fiber web that does not contain any glass fibers.

Example 3

The web was made using a combination of lyocell and eucalyptus fibers as the first top layer. The first layer is formed on a second bottom layer that does not include fibrillated fibers. Eucalyptus is a hardwood pulp with a very small diameter and can help to obtain a dense top layer. The lyocell fibers in the first top layer had an average CSF of about 40 mL. The amount of lyocell and eucalyptus fibers in the first layer varies. The weight per unit area of the first layer is also different.

The second bottom layer had a basis weight of 55 lbs/ream and was formed of RoburFlash (cellulose) fibers:HP-11 fibers:PET (0.6d x 5mm) fibers in a ratio of 1:1:0.46 by weight. Table 1 shows the fraction of lyocell and eucalyptus fibers in the first top layer, the weight per unit area of the first top layer, and the resulting permeability porosity index measured for each sample.

Table 1

*Permeability Pore Index is measured as [Mean Flow Pore Diameter (μm)/(Permeability (cfm/sf)) ^0.5 ].

This example shows that relatively low permeability porosity index values can be obtained by adding lyocell in the first top layer in combination with another pulp. The obtained permeability porosity index values for these samples ranged from 0.8 to 2.25. This example also shows that such values can be obtained in a fiber web that does not include any glass fibers.

Example 4

This experiment shows that varying the fibrillation level of the lyocell fibers in the first top layer of the double layer web can achieve fibrous media with different air permeability.

The first top layer comprised lyocell fibers and the basis weight of this layer varied from 10 lbs/ream to 20 lbs/ream in different samples. The second bottom layer was made of HPZ:softwood kraft pulp:eucalyptus fiber in a weight ratio of 0.34:0.15:0.52 and remained the same for all samples. The Canadian Standard Freeness (CSF) of the lyocell fibers in the top layer varied and was 40 mL, 60 mL, 200 mL, or 250 mL. Permeability porosity index values were measured for each sample as shown in Table 2.

The fiber webs were also tested for basis weight, air permeability, dust holding capacity and efficiency at 4 microns, as shown in Table 3. Multipass filtration tests for efficiency and dust holding capacity were performed according to the ISO 16889/19438 procedure at 25 mg/L Basal Upstream Gravity Level (BUGL), 0.06 cm/sec face velocity, 100 kPa terminal pressure and 1 L/min flow rate .

Table 2

*Permeability Pore Index is measured as [Mean Flow Pore Diameter (μm)/(Permeability (cfm/sf)) ^0.5 ].

table 3

This example shows that different air permeability can be obtained with different levels of fibrillation of lyocell fibers in the first top layer. The fiber web has a permeability porosity index value of less than 3. Furthermore, fiber webs achieve high efficiency values. This example also shows that such values can be obtained in a fiber web that does not include any glass fibers.

Example 5

This example illustrates a method of making a two-layer web comprising a first layer containing cellulose pulp fibers and a layer containing raw Second layer of fibrillated lyocell.

Two-layer handsheets were made using the experimental handsheet mold. The fibers for the first layer (10.8 g of cellulose fibers containing 15% Prince George pulp, 51% eucalyptus fibers, 33% porosanier fibers) were mixed with 1000 mL of water in a blender for 2 minutes to form a first slurry. The first slurry was placed into a handsheet mold and a fibrous web (ie, first layer) was formed on the wire. The web is drained and dried. The web was then placed back into the handsheet mold to serve as the base for the second layer.

The second slurry contained 7.57 g of fibrillated lyocell fiber pulp with 21% solids in 1000 mL of water. The average Canadian Standard Freeness of fibrillated lyocell fibers is 200 mL. The second slurry was placed into the handsheet mold to form a second layer on top of the first layer. The resulting two-layer web was drained and dried. The resulting double layer web had a basis weight of 107.4 gsm and an air permeability of 15.4 cfm/sf.

A layer of meltblown fibers on a scrim having a basis weight of 36.8 gsm and an air permeability of 10 cfm/sf was ordered with the bilayer web to form an integral composite. In this composite said meltblown layer is arranged downstream of the second layer of the double layer web. The average fiber diameter of the melt-blown fibers is 1 micron.

The composite has an air permeability of 6 cfm/sf, a dust holding capacity of 156 gsm and a basis weight of 143.6 gsm. The composite had an initial efficiency of 99.47% on particles 4 microns or larger. The composite has a liquid filtration efficiency of 99.81% for particles 4 microns or larger. The multi-pass filtration test for determination of initial efficiency, liquid filtration efficiency and dust holding capacity was performed according to the ISO16889/19438 procedure at 50 mg/L Basal Upstream Gravity Level (BUGL), 0.06 cm/sec face velocity and 1 L/min flow rate . The initial efficiency is the efficiency at the 4th minute, the 5th minute and the 6th minute after running the test. Liquid filtration efficiency is the efficiency of the media after reaching a terminal pressure of 100 kPa.

This example shows that relatively high dust holding capacities and efficiencies can be achieved for 4 microns in filter media comprising fibrillated fibers in one layer and meltblown fibers in the other layer. Compared to media containing fibrillated fibers with relatively high freeness (e.g., mean CSF values of 80 mL in Example 1, 40 mL in Example 2, and 40 mL in Example 3), in this example Comparable dust holding capacities and efficiencies were achieved due to the use of fibrillated fibers with lower freeness (eg, CSF = 200 mL). This example also shows that such dust holding capacity and efficiency can be achieved in a web that does not contain any glass fibers.

Example 6

This example shows that filter media comprising a meltblown layer can improve the fuel-water separation efficiency of the media.

The composite medium was formed using the procedure described in Example 5. The composite media comprises a two-layer web comprising a first layer comprising cellulose pulp fibers and a first layer comprising fibrils subsequently sequenced with a meltblown layer disposed downstream of the second layer. A second layer of chemically lyocell.

The bilayer web of this example had similar characteristics to the bilayer web described in Example 5, except that the fibrillated lyocell fibers had an average Canadian Standard Freeness of 100 mL.

The meltblown layer did not contain mesh, and had a basis weight of 106 gsm, an air permeability of 25.8 cfm/sf, and an average fiber diameter of 4 to 8 microns.

The composite comprising the bilayer web and the meltblown layer had an initial liquid filtration efficiency of 99.5%, a liquid filtration efficiency of 99.7%, and a fuel-water separation efficiency of 63.2%. The fuel-water separation efficiency of the bilayer web without the meltblown layer was 32.5%.

It is expected that the media described in Example 5 comprising finer meltblown fibers (1 micron) will achieve a greater than 63.2% Fuel-water separation efficiency.

Having thus described several aspects of at least one embodiment of this invention, it is to be appreciated various alterations, modifications, and improvements will readily occur to those skilled in the art. Such alterations, modifications, and improvements are intended to be part of this disclosure, and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description and drawings are examples only.

Claims (39)

1. a kind of filter medium, includes:

First layer, wherein the first layer includes more organic polymer fibers；

The second layer comprising more fibrillating fibres, wherein the second layer be wet laid layer and the second layer have than The low air penetrability of the air penetrability of the first layer；With

Third layer comprising synthetic polymeric fibers, wherein the third layer is non-wet laid layer,

Wherein the first layer and/or the second layer include the glass fibre of 0 weight % to 10 weight %, and

Wherein the filter medium can be realized 60% to 99.9% fuel-water separative efficiency.

2. filter medium according to claim 1, wherein the average Canadian standard of the more fibrillating fibres is free Fibrillation level is spent to be greater than 100 mL and be less than or equal to 300 mL.

3. filter medium according to claim 1, wherein the average Canadian standard of the more fibrillating fibres is free Fibrillation level is spent to be greater than 70 mL and be less than or equal to 90 mL.

4. filter medium according to claim 1, wherein the first layer and/or the second layer include 0 weight % to 5 The glass fibre of weight %.

5. filter medium according to claim 1, wherein the first layer and/or the second layer include less than 1 weight % Glass fibre.

6. filter medium according to claim 1, wherein the second layer includes nonfibrillated fiber.

7. filter medium according to claim 1, wherein the more fibrillating fibres are synthetic fibers.

8. filter medium according to claim 1, wherein the second layer includes fibrillating fibre and nonfibrillated fiber Mixture.

9. filter medium according to claim 1, wherein the more fibrillating fibres include Lyocell fibers.

10. filter medium according to claim 1, wherein the more fibrillating fibres include aromatic polyamide fibre.

11. filter medium according to claim 1, wherein the more fibrillating fibres include rayon fiber.

12. filter medium according to claim 1 the, wherein [mean flow pore size (μm)/(permeability of the second layer (CFM/SF))^0.5] value is less than 1.5.

13. filter medium according to claim 1 the, wherein [mean flow pore size (μm)/(permeability of the second layer (CFM/SF))^0.5] value is less than 1.

14. filter medium according to claim 1, wherein the weight per unit area of the filter medium is greater than 90 g/m²And Less than or equal to 200 g/m²。

15. filter medium according to claim 1, wherein the weight per unit area of the first layer is greater than or equal to 40 g/m²And less than 300 g/m²。

16. filter medium according to claim 1, wherein the weight per unit area of the second layer is greater than or equal to 3 g/ m²And less than 50 g/m²。

17. filter medium according to claim 1, wherein the weight per unit area of the first layer and the second layer The ratio between weight per unit area is at least 3:1 and is less than 5:1.

18. filter medium according to claim 1, wherein the second layer includes greater than 5wt% and to be less than or equal to The fibrillating fibre of 60wt%.

19. filter medium according to claim 1, wherein the first layer contains fibrillating fibre.

20. filter medium according to claim 1, wherein the second layer contains the fibrillation more than or equal to 60wt% Fiber.

21. filter medium according to claim 1, wherein the second layer contains the fibrillation more than or equal to 80wt% Fiber.

22. filter medium according to claim 1 also includes binder resin.

23. filter medium according to claim 1, wherein the dust containing capacity of the filter medium is at least 100 g/m², wherein The dust containing capacity is according to 16889/19438 program of ISO using multi-pass filtration test in 25 basis mg/L upstream weight levels (BUGL), it is measured under the face velocity of 0.06 cm/s and 100 kPa terminal pressures.

24. filter medium according to claim 1, wherein the first layer and/or the second layer are that wet-laying is fine Tie up net.

25. filter medium according to claim 1, wherein the measurer of the fibrillating fibre of the filter medium crosses institute State the gradient of the thickness of filter medium.

26. filter medium according to claim 1, wherein the level of fibrillation of the fibrillated fibers level of the filter medium has There is the gradient for the thickness for crossing the filter medium.

27. filter medium according to claim 1, wherein the filter medium is to 4 microns or the liquid mistake of larger particle Filtering efficiency is at least 99%, wherein the efficiency uses multi-pass filtration test in 25 mg/L according to 16889/19438 program of ISO Basic upstream weight level (BUGL), 0.06 cm/s face velocity and 100 kPa terminal pressures under measure.

28. filter medium according to claim 1, wherein the filter medium is to 4 microns or the liquid mistake of larger particle Filtering efficiency is at least 99.5%, wherein the efficiency uses multi-pass filtration test in 25 mg/ according to 16889/19438 program of ISO It is measured under the basis L upstream weight level (BUGL), the face velocity of 0.06 cm/s and 100 kPa terminal pressures.

29. filter medium according to claim 1, wherein the filter medium is to 4 microns or the liquid mistake of larger particle Filtering efficiency is at least 99.9%, wherein the efficiency uses multi-pass filtration test in 25 mg/ according to 16889/19438 program of ISO It is measured under the basis L upstream weight level (BUGL), the face velocity of 0.06 cm/s and 100 kPa terminal pressures.

30. filter medium according to claim 1, wherein the filter medium includes accessory fibers stratum reticulare.

31. filter medium according to claim 30, wherein the accessory fibers stratum reticulare includes meltblown layer.

32. filter medium according to claim 1, wherein the average Canadian standard of the more fibrillating fibres is free It spends fibrillation level and is less than or equal to 300 mL, be less than or equal to 200 mL, be less than or equal to 100 mL, or be less than or equal to 50 mL。

33. filter medium according to claim 1 is less than wherein the filter medium includes to be less than or equal to 100wt% Or it is equal to 80wt%, it is less than or equal to 60wt%, or the fibrillating fibre less than or equal to 40wt%.

34. filter medium according to claim 1, wherein the more organic polymer fibers are cellulose fibre.

35. filter medium according to claim 1, wherein the second layer includes more fibrillation than the first layer Fiber.

36. filter medium according to claim 35, wherein the second layer includes the fibril chemical fibre than the first layer Tie up the fibrillating fibre with higher fibrillation level.

37. a kind of method, including passing through liquid according to claim 1 to filter medium described in any one of 36.

38. according to the method for claim 37, wherein the liquid is fuel.

39. a kind of filter element, comprising according to claim 1 to filter medium described in any one of 36.