Filter media containing adsorbents

Abstract

A filter medium comprising a fibrous container containing an open phase and a second phase on the open phase, and an adsorbent within the fibrous container, wherein the open phase and the second phase each contain thicker and thinner fibers, and the average diameter of the fibers in the open phase is greater than the average diameter of the fibers in the second phase.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application is an international application claiming priority to U.S. Provisional Application No. 63 / 399,323, filed August 19, 2022, the entire contents of which are incorporated herein by reference.

[0002] Field of Disclosure The present disclosure relates to a filter medium and uses thereof. The present disclosure also relates to a method for making the filter medium and uses of the filter medium for gas removal, for example, for air purification. [Background technology]

[0003] Adsorbents, such as activated carbon particles, can be incorporated into filter media for a variety of purposes, including, but not limited to, gas adsorption filters, vehicle cabin air filters, vehicle intake filters, or heating, ventilation, and air conditioning filters. For example, adsorbents can be used in filter media to remove gases, such as harmful gases, from the air. Filter media containing adsorbents remove contaminants from fluids through surface adsorption, where the contaminants are attracted to the surface of the adsorbent and retained therein through physical attraction and / or chemical bonding.

[0004] To prevent the adsorbent, such as activated carbon particles, from "leaching" from the filter medium, an adhesive may be used to adhere the carbon layer to the fibrous substrate of the filter medium. Thus, the layer of filter medium containing the adsorbent may additionally contain an adhesive. However, a large amount of adhesive, as used in the prior art, may reduce the porosity and reduce the overall effectiveness of the filter medium.

[0005] For example, a slurry of adsorbent and liquid adhesive may be applied to a fibrous substrate. The slurry may form a distinct layer on the fibrous substrate and may not be embedded within the fibrous substrate. The distinct layer may separate or peel from the fibrous substrate. For example, different adhesives perform differently under different environmental conditions, such as temperature, pressure, etc. Additionally, adhesives may reduce the performance of the adsorbent, for example, by clogging the pores of the adsorbent.

[0006] There is interest in improved filter media and related methods of making and using them. The opportunities for improvement are addressed and / or overcome by the filter media, assemblies, and methods of the present disclosure. Summary of the Invention

[0007] The present disclosure provides beneficial filter media and methods of making and using the same. More specifically, the present disclosure provides a beneficial filter medium comprising a fibrous container comprising an open phase and a second phase on the open phase, and a sorbent within the fibrous container, wherein each of the open phase and the second phase comprises a specific combination of thicker and thinner fibers, and the average diameter of the fibers in the open phase is greater than the average diameter of the fibers in the second phase. In one or more embodiments, the thicker fibers have a size of 15-20 denier, and the thinner fibers have a size of 5-10 denier. In the present disclosure, it has been discovered that the specific ratio of thicker to thinner fibers in the open phase and the second phase affects the sorbent loading and overall performance of the filter medium, as discussed in more detail below.

[0008] These and other features are illustrated by the figures and detailed description that follow. Any combination or permutation of embodiments is contemplated. Additional beneficial features, functions, and applications of the disclosed filter media, assemblies, and methods of the present disclosure will become apparent from the following description, particularly when read in conjunction with the accompanying figures. [Brief explanation of the drawings]

[0009] The following diagram is an exemplary embodiment. Features and aspects of the embodiments are described below with reference to the accompanying drawings. Exemplary embodiments of the present disclosure are further described with reference to the accompanying drawings. It should be noted that the various features, steps, and combinations of features / steps described below and illustrated in the drawings can be arranged and configured in different ways to produce embodiments that still fall within the scope of the present disclosure. Reference to the accompanying drawings is provided to assist those skilled in the art in making and using the disclosed filter media, assemblies, and methods. [Figure 1] 1 is a scanning electron microscope (SEM) image of a comparative example filter medium. [Figure 2] 1 is an enlarged SEM image of a filter medium of a comparative example. [Figure 3] 1 is an SEM image of the filter medium of Example 2. [Figure 4] 1 is an enlarged SEM image of the filter medium of Example 2. [Figure 5] 1 is an SEM image of fibers contained in the open phase of the fibrous container of the filter medium of Example 2. [Figure 6] 1 is a magnified SEM image of the fibers contained in the open phase of the fibrous container of the filter medium of Example 2. [Figure 7] 1 is an SEM image of the fibers contained in the second phase of the fibrous container of the filter medium of Example 2. [Figure 8] 1 is a magnified SEM image of the fibers contained in the second phase of the fibrous container of the filter medium of Example 2. [Figure 9] 1 is a graph of n-butane (nB) breakthrough (percent (%)) versus time (minutes (min)) showing nB adsorption for Example 1 and Comparative Example filter media. [Figure 10] 1 is a graph of toluene breakthrough (%) versus time (minutes) showing toluene adsorption for the filter media of Example 1 and the Comparative Example. [Figure 11] 1 is a graph of SO2 breakthrough (%) versus time (min) showing SO2 adsorption for the filter media of Example 1 and the Comparative Example. [Figure 12] 1 is a graph of NO2 breakthrough (%) versus time (min) showing NO2 adsorption for the filter media of Example 1 and the Comparative Example. [Figure 13] 1 is a graph of nB breakthrough (%) versus time (min) showing nB adsorption for the filter media of Example 2. [Figure 14] 1 is a graph of toluene breakthrough (%) versus time (min) showing toluene adsorption for the filter media of Example 2. [Figure 15] 1 is a graph of SO2 breakthrough (%) versus time (min) showing SO2 adsorption for the filter media of Example 2. [Figure 16] 1 is a graph of NO2 breakthrough (%) versus time (min) showing NO2 adsorption for the filter media of Example 2. [Figure 17] 1 is a graph of nitrogen oxide (NOx) breakthrough (%) versus time (min) showing NOx adsorption for the filter media of Example 2. [Figure 18] 1 is a graph of NH3 breakthrough (%) versus time (min) showing NH3 adsorption for the filter media of Example 2. [Figure 19] 1 is a graph of SO2 breakthrough (%) versus time (min) showing SO2 adsorption for the filter media of Example 3. [Figure 20] 1 is a graph of NOx and NO2 breakthrough (%) versus time (minutes) showing NOx and NO2 adsorption for the filter media of Example 3. [Figure 21] 1 is a graph of NH3 breakthrough (%) versus time (min) showing NH3 adsorption for the filter media of Example 3. [Figure 22] 1 is a graph of NH3 breakthrough (%) versus time (min) showing a comparison of NH3 adsorption of the filter media of Example 2 and Example 3. DETAILED DESCRIPTION OF THE INVENTION

[0010] The exemplary embodiments disclosed herein are illustrative of useful filter media and methods / techniques thereof. However, it should be understood that the disclosed embodiments are merely exemplary of the present disclosure, which may be embodied in various forms. Therefore, the details disclosed herein that refer to exemplary filter media and processes / techniques related to assembly and use should not be construed as limiting, but merely as a basis for teaching those skilled in the art how to make and use the useful filter media and / or alternative filter media of the present disclosure.

[0011] The term "nonwoven" refers to a collection of fibers in a web or mat that may be randomly connected, entangled, and / or bonded to one another to form a self-supporting structural element. "Synthetic fibers" refers to fibers made from fiber-forming substances, including polymers synthesized from chemical compounds and modified or converted natural polymeric materials. Such fibers may be produced, for example, by melt spinning, solution spinning, or solvent spinning.

[0012] Exemplary synthetic fibers suitable for the present disclosure are polyesters (e.g., polyalkylene terephthalates such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT)), polyalkylenes (e.g., polyethylene, polypropylene, etc.), polyacrylonitrile (PAN), and polyamides (e.g., nylons such as nylon-6, nylon 6,6, and nylon-6,12). In one embodiment, the synthetic fibers can be bicomponent sheath-core fibers, such as PE-PP fibers, PP-PET fibers, and low-melting PET-PET fibers, or combinations thereof. In one embodiment, the sheath can include a PET copolymer (co-PET); for example, the bicomponent sheath-core fiber can be a co-PET-PET fiber. Bicomponent fibers can have a lower melting point sheath and a higher melting point core.

[0013] The term "adsorption" may be used to refer to the adsorption of a substance, such as a gas, onto an adsorbent, and thus a filter containing an adsorbent may be referred to as an "adsorption" filter. The phrase "spunbond fibers" refers to fibers formed by a process in which fibers are formed by extruding molten thermoplastic polymer material through a plurality of fine capillaries in a spinneret, where the diameter of the extruded fibers is rapidly reduced by drawing. Spunbond fibers may be randomly laid on a collecting surface such as a perforated screen or belt. The phrase "spunbond nonwoven" refers to a nonwoven fabric comprising spunbond fibers that may be bonded by methods such as a hot roll calender, through-air bonding (which may be applicable to multi-component spunbond nonwoven fabrics), or passing the nonwoven fabric through a saturated steam chamber at high pressure.

[0014] The phrase "meltblown fibers" refers to fibers formed by a process in which hot compressed air is applied directly at the die exit. The resulting fibers therefore have a smaller diameter than spunbond fibers. The process for forming meltblown fibers may not include a separate bonding step, and the meltblown fibers are hot enough at the die exit so that they will bond when deposited onto a forming mat.

[0015] Disclosed herein are beneficial filter media and related methods of making and using the same. The present disclosure provides improved filter media and methods of using and making the improved filter media.

[0016] The present disclosure provides a useful filter medium comprising a fibrous container comprising an open phase and a second phase on the open phase, e.g., adjacent or directly on the open phase, and an adsorbent within the fibrous container, wherein the open phase and the second phase each comprise thicker and thinner fibers, and the average pore size of the open phase is larger than the average pore size of the second phase.

[0017] The inventors have surprisingly found that by using a two-layer fibrous "container" comprising an open phase and a second phase, greater amounts of adsorbent can be contained within the fibrous container. It is believed that the open phase structure allows the adsorbent to be supported in the open phase and penetrate the thickness of the material instead of concentrating on the container surface. This allows for greater amounts of adsorbent, e.g., 500 g / m 2The second phase can carry more than 100g of adhesive. Furthermore, the tighter structure due to the ratio of thicker and thinner fibers in the second phase prevents the adsorbent from escaping through the pores. To hold the adsorbent within the fibrous container, e.g., in an open layer, little or no adhesive may be provided within, e.g., on, the fibrous container, increasing the effective utilization of the surface area of ​​the filter medium and producing better filtration performance. In one embodiment, the amount of adhesive provided within, e.g., on, the fibrous container is less than 10 weight percent (wt%) based on the total weight of the adsorbent. In one embodiment, the amount of adhesive provided within, e.g., on, the fibrous container is 0 wt% based on the total weight of the adsorbent. The use of little or no adhesive provides improved performance.

[0018] Using little or no adhesive can enable better performance. Equivalent or better performance can be achieved with the disclosed filter media compared to filter media with more adhesive, which can affect gas adsorption performance. The gas adsorption performance of the adsorbent can be reduced due to a reduction in the surface area of ​​the adsorbent by the liquid adhesive, e.g., clogging or coating of pores. Furthermore, the liquid adhesive can block the pores of the fibrous substrate. For example, FIG. 1 shows a filter media with a liquid adhesive (indicated by the arrow) coating the activated carbon particles.

[0019] The use of little or no adhesive may also allow different adsorbents to be used depending on the desired properties and end use of the filter media. The choice of adsorbent may be tailored to the desired properties and end use of the filter media, such that interactions between the adhesive and the adsorbent, such as pore clogging or coating of the adsorbent by the adhesive, may be minimized or absent.

[0020] The pore size gradient between the open phase and the second phase results in more effective sorbent loading, utilization, distribution, or a combination thereof, throughout the thickness of the fibrous container, resulting in improved performance due to more effective utilization of surface area for filtration. The average pore size in each of the open phase and the second phase can be the result of different fiber sizes, e.g., denier, diameter, or a combination thereof, in each of the phases. The open phase can contain fewer pores than the second phase, but the pores of the open phase can be larger than those of the second phase, e.g., the open phase can have a larger average pore diameter than the second phase.

[0021] The adsorbent retention is due to the asymmetric / gradient fiber structure of the filter media. For example, the pore size gradient provided by the tighter second phase on the open phase can help retain the adsorbent in large quantities within the fiber container and prevent a large amount, e.g., a majority, of the adsorbent from collecting on the surface of the fiber container opposite the surface to which the adsorbent is added. The presence of a large amount of adsorbent on the surface of the fiber container can, for example, lead to peeling of this surface of the fiber container from a coating layer laminated to the surface of the fiber container, or an asymmetric structure of the filter media, which can adversely affect the pleating process used to form the filter media.

[0022] In one embodiment, the average pore size of the open phase is larger than the average pore size of the second phase. In one embodiment, the proportion of thicker fibers in the open phase is less than the proportion of thinner fibers in the open phase. In one embodiment, the proportion of thicker fibers in the second phase is less than the proportion of thinner fibers in the second phase. In one embodiment, the proportion of thicker fibers in the open phase is greater than the proportion of thicker fibers in the second phase. In one embodiment, the proportion of thinner fibers in the open phase is less than the proportion of thinner fibers in the second phase. As used herein, percentage may refer to the weight percentage of the stated fiber type relative to the total fiber weight in the stated phase.

[0023] Fiber containers are 30 to 120 grams per square meter (g / m 2 ), e.g., 60-90g / m 2The fiber container may comprise 50-70% by weight of the open phase and 30-50% by weight of the second phase, based on the total weight of the fiber container.

[0024] In one embodiment, the thicker fibers are present in the open phase in an amount of 30 to 50 weight percent, based on the total fiber weight of the open phase. In one embodiment, the thicker fibers comprise fibers of 15 to 20 denier. In one embodiment, the finer fibers are present in the open phase in an amount of 50 weight percent or more, e.g., 50 to 70 weight percent, based on the fiber weight of the open phase. In one embodiment, the finer fibers comprise fibers of 5 denier to less than 10 denier, or fibers of 7 denier to less than 10 denier. In one embodiment, the thicker fibers are present in the second phase in an amount of 10 to 20 weight percent, based on the fiber weight of the second phase. In one embodiment, the finer fibers are present in the second phase in an amount of 80 to 90 weight percent, based on the fiber weight of the second phase. In one embodiment, the finer fibers are present in the second phase in an amount of 50 or more, based on the fiber weight of the second phase.

[0025] The open phase may comprise 30-50% by weight of synthetic fibers between 15 and 20 denier, and 50-70% by weight of synthetic fibers between 5 and less than 10 denier, e.g., between 7 and less than 10 denier, based on the total weight of the open phase. The second phase may comprise 10-30% by weight of synthetic fibers between 10 and 20 denier, and 70-90% by weight of synthetic fibers between 5 and less than 10 denier, e.g., between 7 and less than 10 denier, based on the total weight of the second phase. Denier may be measured by ASTM D-1577.

[0026] The fibers included in the fiber container may, for example, comprise low melting point fibers in an amount of 50% by weight or more, or 50-70% by weight, based on the total fiber weight of the fiber container. As used herein, the phrase "low melting point fibers" may refer to bicomponent sheath-core fibers having a sheath with a low melting point and a core with a higher melting point.

[0027] In one embodiment, the thicker fibers comprise polyethylene terephthalate fibers.In one embodiment, the thinner fibers comprise polyethylene terephthalate fibers. In one embodiment, the fibers included in the fibrous container may include, for example, 50% by weight or less, or 30-50% by weight of regular PET fibers, based on the total weight of the PET fibers (e.g., based on the total weight of the regular PET fibers and the low-melting PET fibers). As used herein, "regular" PET fibers may have a single component with a melting point of about 265°C.

[0028] The fibrous container comprising the open phase and the second phase may be a thermally bonded nonwoven, for example, the open phase and the second phase may be thermally bonded to each other. The filter medium may comprise at least one additional spunbond nonwoven laminated on at least one surface of the fibrous container. In one embodiment, the filter medium may comprise an additional spunbond nonwoven laminated on the opposite surface of the fibrous container to prevent the release of the adsorbent from the surface of the fibrous container.

[0029] A fiber container comprising an open phase and a second phase can be produced by two carding machines. The open phase and the second phase formed by the two carding machines can be fed into a belt hot air dryer and combined into a fiber container. The second phase can be placed on the belt surface to create pores smaller than those of the open phase. Any suitable type of air passing through the dryer can be used to bond the two layers, for example, a belt-type air-through dryer can be used to produce a fiber container with a pore size gradient.

[0030] To insert the sorbent into the fiber container, the sorbent may be dispersed onto the open phase in one step. In one embodiment, the sorbent may be dispersed in multiple steps. However, even when the sorbent is dispersed in multiple steps, the container structure should be advantageously selected so that the initially dispersed sorbent is not retained solely in the open phase and prevents subsequent sorbents from entering the interior of the fiber container.

[0031] The adsorbent is 50 g / m 2Over, for example, 100 g / m 2 Super, 200g / m 2 Super, 300g / m 2 Super, 500g / m 2 Over 600g / m 2 In one embodiment, the adsorbent may be present in an amount of greater than 1,000 g / m 2 Less than, for example, 900 g / m 2 Less than or 800g / m 2 In one embodiment, the adsorbent is present in an amount of less than 50 g / m 2 ~1,000g / m 2 , e.g., 500g / m 2 ~900g / m 2 , or 600 g / m 2 ~800g / m 2 is present in an amount of

[0032] Exemplary adsorbents for use in the disclosed filter media include particles such as activated carbon particles, silica, zeolite, molecular sieves, clay, alumina, sodium bicarbonate, ion exchange resins, catalysts including enzymes, metal oxides, air fresheners, or fragrance particles, such as titanium dioxide, or combinations thereof. Bactericidal particles can be incorporated into filter media, such as for automotive climate control systems, to remove mold and mildew odors from circulating air. Biocidal particles, virucidal particles, or combinations thereof can be incorporated into filter media.

[0033] In one embodiment, the adsorbent includes activated carbon particles, silica, zeolite, molecular sieves, clay, alumina, sodium bicarbonate, ion exchange resin, catalyst, or a combination thereof. In one embodiment, the adsorbent includes activated carbon particles. In one embodiment, the adsorbent includes activated carbon particles and an ion exchange resin. The ion exchange resin may, for example, assist in NH3 adsorption.

[0034] In one embodiment, the activated carbon particles include activated carbon powder, e.g., a powder formed by particles having an average particle size ranging from 0.05 to 1.5 millimeters (mm), e.g., 0.1 to 1.5 mm, 0.15 to 1.0 mm, or 0.3 to 1.0 mm. The activated carbon particles can be impregnated with an acid or base to adsorb basic or acidic gases, respectively. For example, the activated carbon particles can be impregnated with H3PO4 (phosphoric acid) (e.g., in an amount of 20 wt.% based on the total weight of the impregnated activated carbon particles) or KI (potassium iodide) (e.g., in an amount of 3 wt.% based on the total weight of the impregnated activated carbon particles). In one embodiment, the adsorbent includes different impregnated activated carbon particles, e.g., H3PO4-impregnated activated carbon particles and KI-impregnated activated carbon particles. In one embodiment, the adsorbent includes impregnated activated carbon particles and an ion exchange resin. In one embodiment, the activated carbon can have a size of 20 to 80 mesh, e.g., 0.17 to 0.85 mm diameter.

[0035] The inclusion of different adsorbents, e.g., activated carbon particles, impregnated activated carbon particles, ion exchange resins, or combinations thereof, may enable a single filter medium to treat, for example, multiple, e.g., two, three, four, or more than four different compounds, e.g., volatile organic compounds (VOCs), at the particulate level. For example, filter media containing different adsorbents may enable at least two of the following: 99.5% particle efficiency for 0.3 micrometer (μm) NaCl at 20 centimeters per second (cm / s) (DIN 71460-1); 1% target n-butane initial breakthrough at 10 cm / s (DIN 71460-2); 1.5% target SO2 initial breakthrough at 10 cm / s (DIN 71460-2); 0% target NOx initial breakthrough at 10 cm / s (DIN 71460-2); or 0% target NH3 initial breakthrough at 10 cm / s (DIN 71460-2).

[0036] In one embodiment, the adsorbent may include zeolite, alumina, ion exchange resin, or a combination thereof. The zeolite, alumina, ion exchange resin, or a combination thereof has a density of 0.5 to 0.7 grams per cubic meter (g / cm). 3 ) and a size of 20-80 mesh. In one embodiment, such adsorbents can be used alone or in a mixture with activated carbon particles. In one embodiment, a mixture of modified, e.g., impregnated activated carbon and ion exchange resins can provide improved gas adsorption properties.

[0037] The process for forming the disclosed filter media can include combining / carding an open phase and a second phase together to form a thermally bonded fibrous "canister." A first carding machine can form the open phase and a second carding machine can form the second phase.

[0038] Forming the fibrous container can include mixing thicker and thinner fibers in the open phase and the second phase. The open phase and the second phase can be needled together, such as by needle punching. In one embodiment, the open phase and the second phase can be thermally bonded in an air-through dryer.

[0039] In one embodiment, the disclosed filter media can be formed by a process that includes forming a fibrous container, providing a sorbent on the fibrous container, and stacking the fibrous containers to form the filter media. In one embodiment, the process further includes providing an adhesive on the fibrous container after adding the sorbent on the fibrous container.

[0040] In one embodiment, the adhesive comprises a powder. In one embodiment, the adhesive comprises a web. In one embodiment, the adhesive is not present in the second phase. In one embodiment, less than 1 wt. % of the adhesive is present in the second phase, based on the total weight of the second phase. The amount of adhesive can be determined, for example, by pyrolysis gas chromatography / mass spectrometry (GC-MS). In one embodiment, forming the fibrous container comprises mixing thicker and thinner fibers in the open phase and the second phase.

[0041] The open phase can be disposed on top of the second phase. If the adsorbent is provided, for example, dispersed on a fiber container, gravity can help the adsorbent fall into the open phase of the fiber container. The pore size gradient can help retain larger adsorbent particles on the upper surface of the fiber container and allow smaller adsorbent particles to fall further into the fiber container.

[0042] In one embodiment, the filter medium further comprises a coating layer. In one embodiment, the coating layer comprises spunbond fibers. In one embodiment, the coating layer comprises an electrostatically charged layer, for example, electrostatically charged meltblown fibers. Furthermore, the adhesive present in the filter medium may only be present at the interface between the fibrous container and the coating layer; for example, after applying the adhesive to the fibrous container, the adhesive may not penetrate into the fibrous container.

[0043] The opposite surface of the fiber container can be laminated with a spunbond nonwoven fabric as a covering layer. The spunbond nonwoven fabric can, for example, prevent the adsorbent from leaving, for example, the surface of the fiber container. Exemplary methods for laminating the spunbond nonwoven fabric to the fiber container include hot melt spray lamination, hot melt powder lamination, and hot melt web lamination. In one embodiment, the thickness of the fiber container may not be reduced during lamination. If the thickness of the fiber container is reduced too much during lamination, the fiber container may not function properly to retain the adsorbent.

[0044] Spunbond nonwoven fabrics used for laminating fiber containers can be relatively thin and have good air permeability. For example, spunbond nonwoven fabrics can be 10 to 40 g / m 2 In one embodiment, the spunbond nonwoven fabric may comprise PP or PET spunbond fibers of 15 to 30 g / m 2 The spunbond nonwoven may comprise PP or PET spunbond fibers of 30 to 70 g / m. The spunbond nonwoven may have a thickness of 0.10 to 0.40 mm. In one embodiment, instead of the spunbond nonwoven, 2 A calendered thermally bonded nonwoven fabric having a basis weight of 0.20 to 0.40 mm and a thickness of 0.20 to 0.40 mm can be laminated to the fibrous container.

[0045] The spunbond nonwoven fabric may contain one or more additive components. The additive components may be, for example, dyes, fiber retention agents, separation aids (e.g., silicone additives and related catalysts), fire retardants, hydrophilic or hydrophobic agents, wetting agents, antistatic agents, antimicrobial agents, or combinations thereof, which may be required to impart a desirable appearance to the filter media. If present, these additives may be present in an amount of more than 0 wt%, more than 0.01 wt%, more than 0.1 wt%, more than 1 wt%, more than 5 wt%, more than 10 wt%, and / or less than about 30 wt%, less than 25 wt%, less than 20 wt%, less than 15 wt%, less than 10 wt%, less than 9 wt%, less than 8 wt%, less than 7 wt%, less than 6 wt%, less than 5 wt%, less than 4 wt%, less than 3 wt%, less than 2 wt%, less than 1 wt%, or combinations thereof (e.g., including 0.1 wt% to 10 wt%) based on the total weight of the coating layer.

[0046] The adsorbent can be spread by a diffuser on a fiber container laminated with a spunbond nonwoven fabric. The adsorbent can be spread by several diffusers. In the settling stage, the adsorbent is spread by one diffuser. When the adsorbent is spread by multiple diffusers, the first diffused adsorbent may block the pores on the surface of the fiber container, preventing the adsorbent that is subsequently diffused from entering the interior of the fiber container. A brush or a vibrating device can be used to help the dispersed adsorbent enter the interior of the fiber container.

[0047] In one embodiment, after the sorbent is spread on the fiber container, a brushing technique, for example, two or three times, may be used to help the sorbent penetrate the pores of the fiber container. Smaller sorbent particles may fall or be pushed further into the fiber container, while larger sorbent particles may remain at or toward the top of the fiber container.

[0048] A hot melt powder adhesive, a hot melt web adhesive, or a combination thereof can be applied to a fibrous container containing an adsorbent, for example, to laminate the fibrous container containing the adsorbent and a coating layer. The hot melt powder can be used in an amount of 10% by weight or less, based on the total adsorbent weight. The hot melt powder can be made from polyurethane (PU), PET, ethylene-vinyl acetate (EVA), polyamide (PA), or copolymers thereof. The hot melt powder can have a diameter of 0.1 to 0.4 mm. The hot melt powder can have a melting point of 70 to 160°C. The hot melt powder adhesive can bond the adsorbent located on the surface of the fibrous container. In one embodiment, the hot melt powder can be applied in an amount of 0 to 60 30 g / m. 2 The substrate may have a basis weight of more than 1000 gram.

[0049] In one embodiment, the fiber container comprises an amount of adhesive greater than 0% and less than 10% by weight based on the total weight of the sorbent, hi one embodiment, the fiber container comprises less than 1% by weight, e.g., 0% by weight, of adhesive based on the total weight of the sorbent.

[0050] Hot melt web adhesive: 5 to 30 g / m 2 , e.g., 10 g / m 2 Exemplary hot melt web adhesives may include polyurethane PU, EVA, polyamide PA, PET, or copolymers thereof. The hot melt web adhesive may bond the absorbent layer and the cover layer.

[0051] The cover layer laminated with the adsorbent layer can be the same nonwoven fabric used to laminate the fibrous container. If an additional layer with a filtration efficiency layer, such as meltblown, is required, another cover layer thinner than the first can be used.

[0052] The final filter medium can be formed by lamination; for example, the layers can be heated and bonded together. For example, a flatbed laminator can be used. The lamination process can be controlled by adjusting the machine speed, e.g., 3-10 meters / minute (m / min), the temperature, e.g., 130-200°C, and the pressure, e.g., 0-5 megapascals (MPa). The final filter medium can be formed with or without a calendering step. During lamination, e.g., a belt-dry lamination process, the adsorbent can enter the fiber container or migrate further within the fiber container.

[0053] In one embodiment, one or more additional layers of the filter media may include an "efficiency layer" for higher particle filtration efficiency. The efficiency layer may include, for example, nanofibers, meltblown fibers, expanded polytetrafluoroethylene (ePTFE) membrane, electrically charged needle felt, nonwoven fabric containing microglass fibers, or combinations thereof. In one embodiment, the efficiency layer may have a basis weight of 15 to 30 g / m2 and may include PP meltblown fibers. In one embodiment, the efficiency layer includes an electrostatically charged layer, for example, electrostatically charged meltblown fibers.

[0054] Filter media: 700 to 1,390 g / m 2 For example, the paper may have a basis weight of 700 g / m 2 The filter media has a basis weight of 500 g / m without an efficiency layer. 2 and 1,390 g / m 2 The filter media with a basis weight of 1,000 g / m2 with an efficiency layer 2 The adsorbent may include:

[0055] The filter medium may have a thickness of 2.0 mm or more, for example, 2.4 mm or more. The directed thickness may be the stacking direction of the open phase on the second phase. The filter medium may have a thickness of 4.0 mm or less, for example, less than 2.5 mm, and the fibrous container may have a thickness of 3.5 mm or less. A thinner filter medium provides a lower air permeability of the filter medium, and a thicker filter medium provides a higher air permeability of the filter medium. In one embodiment, the filter medium has a thickness of less than 2.5 mm to aid pleating. A filter medium with a thickness greater than 2.5 mm may be difficult to pleat.

[0056] The air permeability of the filter media can be between 5 and 200 cubic feet per minute (cfm), depending on the efficiency layer. For example, an efficiency layer containing meltblown fibers can have a low air permeability, reducing the overall air permeability of the filter media.

[0057] To prevent the fiber container from peeling off from the adjacent covering layer or additional layer, an adhesive web may be added between the fiber container and the adjacent covering layer or additional layer. The adhesive web may have a thickness of 5 to 30 g / m 2 , e.g., 10 g / m 2 Exemplary adhesive webs may include PU, EVA, PA, PET, or copolymers thereof.

[0058] The filter media can be configured for use as a fuel cell intake filter. The filter media can filter particles to limit clogging of channels and proton exchange membranes in the fuel cell. The filter media can remove volatile organic compounds (VOCs), SO2, NOx, NH3, or combinations thereof, extend the life of the fuel cell catalyst (e.g., platinum), and improve fuel cell service intervals. For example, the disclosed filter media can be suitable for applications including intake filter media for fuel cells in electric vehicles (EVs).

[0059] The filter media may be configured to filter automobile cabin air, for example, the disclosed filter media may be suitable for applications including cabin filter media for EVs. The filter media may be configured to filter particulates (such as dust, pollen, soot, bacteria, and particulate matter 2.5 (PM2.5)), gases (such as ozone, benzene, sulfur oxides (SOx), and NOx), odors, or combinations thereof, from the cabin air.

[0060] The air filter media can be configured as an automobile engine intake filter, which can be configured to filter particulates (such as dust, pollen, soot, bacteria, and PM2.5) from the air entering the vehicle's engine. The air filter media can be configured for, among other things, gas turbine intake filters, air-oil separation filters (e.g., for compressed air applications), air pollution control and dust collection filter elements (such as those used to reduce or eliminate particle emissions into the atmosphere from industrial sources), or heating, ventilation, and air conditioning (HVAC) filter elements. The air filter media can be configured as an HVAC molecular filter. The air filter media can be configured as an indoor air purifier.

[0061] Thus, gas adsorption filters, vehicle cabin air filters, vehicle intake filters, or heating, ventilation, and air conditioning filters may contain the disclosed filter media. Depending on the end use of the product, the filtration characteristics and properties of the disclosed filter media may vary.

[0062] The present disclosure is further illustrated by the following non-limiting examples. [Example]

[0063] Comparative Example The comparative example included activated carbon and a hot melt spray adhesive used to adhere the activated carbon particles and laminate the nonwoven fabric layer. Figure 1 is an SEM image of the comparative example filter media, and Figure 2 is a magnified SEM image of the comparative example filter media.

[0064] Example 1 25g / m 2 Spunbond nonwoven fabric containing PET fiber at 5g / m2 90g / m2 hot melt powder adhesive 2 The open phase of the fibrous container contained 50% by weight of 15 denier bicomponent PET fibers and 50% by weight of 6 denier bicomponent PET fibers. The second phase of the fibrous container contained 30% by weight of 15 denier bicomponent PET fibers and 70% by weight of 6 denier bicomponent PET fibers. The weights of the open phase and second phase were each 45 g / m 2 It was.

[0065] The fiber container is made of 700g / m2 impregnated with 3% by weight of KI (potassium iodide). 2 The impregnated activated carbon had a size of 30-80 mesh. After adding the activated carbon particles, another 25 g / m 2 A 60 g / m PET fiber spunbond nonwoven fabric was laminated to the opposite surface of the fibrous container using a flatbed laminator at a machine speed of 4 m / min, a laminator temperature of 160-190 °C, and a lamination pressure of 4 MPa. 2 hot melt powder adhesive, and 10g / m made from co-PET 2 A hot melt web adhesive was used.

[0066] 30g / m as the efficiency layer 2 The E10-grade meltblown nonwoven fabric, containing PP meltblown fibers and a basis weight of 100g, was used. The efficiency layer had an efficiency of 86.2% at a test airflow rate of 32 LPM and a 0.3 micrometer NaCl test aerosol. The meltblown nonwoven fabric was laminated with a hot melt web adhesive made from co-PET.

[0067] Example 2 25 grams per square meter (g / m 2 ) spunbond nonwoven fabric containing polyethylene terephthalate (PET) fibers at 5 g / m 2 90g / m2 hot melt powder adhesive 2The open phase of the fibrous container contained 50 weight percent (wt%) 15 denier bicomponent PET fibers and 50 wt% 6 denier bicomponent PET fibers. The second phase of the fibrous container contained 30 wt% 15 denier bicomponent PET fibers and 70 wt% 6 denier bicomponent PET fibers. The weights of the open phase and second phase were each 45 g / m 2 It was.

[0068] The fibrous container is made of 500g / m2 impregnated with 3% by weight of KI. 2 200g / m2 of activated carbon particles impregnated with 20% by weight of H3PO4 (phosphoric acid) 2 After adding the activated carbon particles, another 25 g / m 2 A 60 g / m PET fiber spunbond nonwoven fabric was laminated to the opposite surface of the fibrous container using a flatbed laminator at a machine speed of 4 meters per minute (m / min), a laminator temperature of 160-190°C, and a lamination pressure of 4 megapascals (MPa). 2 hot melt powder adhesive, and 10g / m made from co-PET 2 A hot melt web adhesive was used.

[0069] 30g / m as the efficiency layer 2 The meltblown nonwoven fabric used was an H13-grade fabric containing PP meltblown fibers and had a basis weight of 1000 sq ft. The efficiency layer had an efficiency of 99.97% at a test airflow rate of 32 LPM and a 0.3 micrometer NaCl test aerosol. The meltblown nonwoven fabric was laminated with a hot melt web adhesive made from co-PET.

[0070] Figure 3 is a scanning electron microscope (SEM) image of the filter material of Example 2, Figure 4 is an enlarged SEM image of the filter material of Example 2, Figure 5 is an SEM image of the fibers contained in the open phase of the fibrous container of the filter material of Example 2, Figure 6 is an enlarged SEM image of the fibers contained in the open phase of the fibrous container of the filter material of Example 2, Figure 7 is an SEM image of the fibers contained in the second phase of the fibrous container of the filter material of Example 2, and Figure 8 is an enlarged SEM image of the fibers contained in the second phase of the fibrous container of the filter material of Example 2.

[0071] Example 3 Example 3 is a 560 g / m2 woven fabric impregnated with 3 wt% KI. 2 activated carbon particles of 140 g / m2 with a matrix of polystyrene and divinylbenzene and sulfonic acid functional groups 2 and a dry ion exchange resin.

[0072] The physical properties of Examples 1-3 and the Comparative Example are provided in Table 1.

[0073] [Table 1]

[0074] Figure 9 is a graph of n-butane (nB) breakthrough (percentage (%)) versus time (minutes (min)) showing the nB adsorption of the filter media of Example 1 and the comparative example; Figure 10 is a graph of toluene breakthrough (%) versus time (min) showing the toluene adsorption of the filter media of Example 1 and the comparative example; Figure 11 is a graph of SO2 breakthrough (%) versus time (min) showing the SO2 adsorption of the filter media of Example 1 and the comparative example; and Figure 12 is a graph of NO2 breakthrough (%) versus time (min) showing the NO2 adsorption of the filter media of Example 1 and the comparative example.

[0075] Example 1 showed better performance in adsorbing n-butane and NO2, and similar performance in adsorbing toluene and SO2 compared to the comparative example containing a higher loading of activated carbon particles.

[0076] Figure 13 is a graph of nB breakthrough (%) versus time (minutes) showing the nB adsorption of the filter material of Example 2, Figure 14 is a graph of toluene breakthrough (%) versus time (minutes) showing the toluene adsorption of the filter material of Example 2, Figure 15 is a graph of SO2 breakthrough (%) versus time (minutes) showing the SO2 adsorption of the filter material of Example 2, Figure 16 is a graph of NO2 breakthrough (%) versus time (minutes) showing the NO2 adsorption of the filter material of Example 2, Figure 17 is a graph of NOx breakthrough (%) versus time (minutes) showing the nitrogen oxide (NOx) adsorption of the filter material of Example 2, and Figure 18 is a graph of NH3 breakthrough (%) versus time (minutes) showing the NH3 adsorption of the filter material of Example 2.

[0077] Figure 19 is a graph of SO2 breakthrough (%) versus time (min) showing the SO2 adsorption of the filter material of Example 3, Figure 20 is a graph of NOx and NO2 breakthrough (%) versus time (min) showing the NOx and NO2 adsorption of the filter material of Example 3, and Figure 21 is a graph of NH3 breakthrough (%) versus time (min) showing the NH3 adsorption of the filter material of Example 3.

[0078] Figure 22 is a graph of NH3 breakthrough (%) versus time (min) showing a comparison of NH3 adsorption of the filter media of Example 2 and Example 3. Figure 22 shows the technical benefits of using ion exchange resins for NH3 adsorption.

[0079] The present disclosure further includes the following aspects. Aspect 1. A filter medium comprising a fibrous container comprising an open phase and a second phase on the open phase, and an adsorbent within the fibrous container, wherein the open phase and the second phase each comprise thicker and thinner fibers, and the average diameter of the fibers in the open phase is greater than the average diameter of the fibers in the second phase.

[0080] Embodiment 2. The filter medium of embodiment 1, wherein the average pore size of the open phase is greater than the average pore size of the second phase. Aspect 3. The filter medium of Aspect 1 or 2, wherein the proportion of thicker fibers in the open phase is less than or equal to the proportion of thinner fibers in the open phase.

[0081] Embodiment 4. The filter medium of any one or more of the preceding embodiments, wherein the proportion of thicker fibers in the second phase is less than the proportion of thinner fibers in the second phase. Embodiment 5. The filter medium of any one or more of the preceding embodiments, wherein the proportion of thicker fibers in the open phase is greater than the proportion of thicker fibers in the second phase.

[0082] Embodiment 6. The filter medium of any one or more of the preceding embodiments, wherein the proportion of finer fibers in the open phase is less than the proportion of finer fibers in the second phase. Embodiment 7. The filter medium of any one or more of the preceding embodiments, wherein the thicker fibers are present in the open phase in an amount of 30 to 50 weight percent, based on the total fiber weight of the open phase.

[0083] Embodiment 8. The filter medium of any one or more of the preceding embodiments, wherein the thicker fibers comprise fibers of 15 to 20 denier. Embodiment 9. The filter medium of any one or more of the preceding embodiments, wherein the finer fibers are present in the open phase in an amount of 50 to 70 weight percent, based on the weight of the fibers in the open phase.

[0084] Embodiment 10. The filter medium of any one or more of the preceding embodiments, wherein the finer fibers comprise fibers from 5 denier to less than 10 denier or fibers from 7 denier to less than 10 denier. Embodiment 11. The filter medium of any one or more of the preceding embodiments, wherein the thicker fibers are present in the second phase in an amount of 10 to 20 weight percent, based on the weight of the fibers in the second phase.

[0085] Embodiment 12. The filter medium of any one or more of the preceding embodiments, wherein the finer fibers are present in the second phase in an amount of 80 to 90 weight percent, based on the fiber weight of the second phase. Embodiment 13. The filter medium of any one or more of the preceding embodiments, wherein the thicker fibers comprise polyethylene terephthalate fibers.

[0086] Embodiment 14. The filter medium of any one or more of the preceding embodiments, wherein the finer fibers comprise polyethylene terephthalate fibers. Embodiment 15. The filter medium of any one or more of the preceding embodiments, wherein the fibrous container comprises an adhesive in an amount greater than 0 weight percent and less than 10 weight percent, based on the total weight of the sorbent.

[0087] Embodiment 16. The filter medium of any one or more of embodiments 1-14, wherein the fibrous container comprises less than 1 weight percent or 0 weight percent adhesive, based on the total weight of the sorbent. Aspect 17. The filter medium of any one or more of the preceding aspects, wherein the adsorbent comprises activated carbon particles, silica, zeolite, molecular sieve, clay, alumina, sodium bicarbonate, an ion exchange resin, a catalyst, or a combination thereof.

[0088] Embodiment 18. The filter medium of embodiment 17, wherein the adsorbent comprises activated carbon particles, impregnated activated carbon particles, an ion exchange resin, or a combination thereof. Embodiment 19. The filter medium of any one or more of the preceding embodiments, further comprising a coating layer.

[0089] Embodiment 20. The filter medium of embodiment 19, wherein the cover layer comprises spunbond fibers. Embodiment 21. The filter medium of embodiment 19 or 20, further comprising an adhesive, wherein the adhesive is present only at the interface between the fibrous container and the cover layer.

[0090] Embodiment 22. The filter medium of any one or more of the preceding embodiments, having a thickness of 4.0 millimeters or less. Embodiment 23. The filter medium of any one or more of the preceding embodiments, having a thickness of less than 2.5 millimeters.

[0091] Embodiment 24. The filter medium of any one or more of the preceding embodiments, wherein the filter medium is pleated. Embodiment 25. A gas adsorption filter comprising the filter medium of any one or more of the preceding embodiments.

[0092] Aspect 26. A cabin air filter for a vehicle, comprising the filter media of any one or more of the preceding aspects. Aspect 27. An intake air filter for a vehicle, comprising the filter media of any one or more of the preceding aspects.

[0093] Aspect 28. A heating, ventilation, and air conditioning filter comprising the filter media of any one or more of the preceding aspects. Embodiment 29. The filter medium of any one or more of the preceding embodiments, formed by a process including forming a fiber container, providing a sorbent on the fiber container, and stacking the fiber containers to form the filter medium.

[0094] Embodiment 30. The filter medium of embodiment 29, wherein the process further comprises providing an adhesive on the fiber container after applying the sorbent on the fiber container. Embodiment 31. The filter medium of embodiment 30, wherein the adhesive comprises a powder.

[0095] Embodiment 32. The filter medium of embodiment 30 or 31, wherein the adhesive comprises a web. Embodiment 33. The filter medium of any one or more of embodiments 30-32, wherein the adhesive is not present in the second phase.

[0096] Embodiment 34. The filter medium of any one or more of embodiments 30-32, wherein less than 1 weight percent adhesive is present in the second phase, based on the total weight of the second phase. Embodiment 35. The filter medium of any one or more of embodiments 30-34, wherein forming the fibrous vessel comprises mixing thicker and thinner fibers in the open phase and the second phase.

[0097] While particular embodiments have been described, alternatives, modifications, variations, improvements, and substantial equivalents, which are presently unforeseen or may be unforeseeable, may occur to applicant or those skilled in the art. Accordingly, the appended claims, as filed and as they may be amended, are intended to embrace all such alternatives, modifications, variations, improvements, and substantial equivalents.

[0098] When an element is referred to as being "on" another element, it will be understood that it can be directly on the other element, or there can be intervening elements. In contrast, when an element is referred to as being "directly" on another element, there are no intervening elements present.

[0099] All ranges disclosed herein are inclusive of the endpoints, and the endpoints are independently combinable with each other (e.g., the range "up to 25 wt.%, or more specifically, 5 wt.% to 20 wt.%" includes the endpoints and all intermediate values ​​in the "5 wt.% to 25 wt.%" range, etc.). A "combination" is inclusive of blends, mixtures, alloys, reaction products, and the like. Terms such as "first," "second," and the like do not denote any order, amount, or importance, but rather are used to distinguish one element from another. The terms "a," "an," and "the" do not denote limitations of quantity and should be construed to encompass both the singular and the plural unless otherwise indicated herein or clearly contradicted by context. "Or" means "and / or" unless expressly stated otherwise. References throughout this specification to "some embodiments," "one embodiment," etc. mean that the particular element described in connection with an embodiment is included in at least one embodiment described herein and may or may not be present in other embodiments. In addition, it is to be understood that the described elements may be combined in any suitable manner in the various embodiments. "Combinations thereof" is open-ended and includes any combination that includes at least one of the recited components or properties, optionally with similar or equivalent components or properties that are not recited.

[0100] Relative terms such as "lower" or "bottom" and "upper" or "top" may be used herein to describe the relationship of one element to another, as illustrated in the figures. It will be understood that the relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the figures. For example, if a device in one of the figures is turned over, an element described as being on the "lower" side of the other element would then be positioned on the "upper" side of the other element. Thus, the exemplary term "lower" can encompass both an orientation of "lower" and "upper," depending on the particular orientation of the figure. Similarly, if a device in one of the figures is turned over, an element described as being "below" or "below" the other element would then be positioned "above" the other element. Thus, the exemplary terms "lower" or "below" can encompass both an orientation of above and below.

[0101] Unless otherwise defined, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. All cited patents, patent applications, and other references are incorporated herein by reference in their entirety. However, if a term from this application contradicts or conflicts with a term in an incorporated reference, the term from this application shall take precedence over the conflicting term from the incorporated reference.

[0102] Unless otherwise specified herein, all test specifications are the latest specifications in effect as of the filing date of this application, or, if priority is claimed, the specifications in effect as of the filing date of the earliest priority application in which the test specifications are listed.

[0103] Although the filter media and methods of the present disclosure have been described with reference to exemplary embodiments thereof, the present disclosure is not limited to such exemplary embodiments and / or implementations. Rather, the filter media and methods of the present disclosure are susceptible to numerous implementations and applications, as will be readily apparent to those skilled in the art from the disclosure herein. The present disclosure expressly encompasses such modifications, enhancements, and / or variations of the disclosed embodiments. Because numerous changes can be made to the above structures, and many widely different embodiments of the present disclosure can be made without departing from the scope of the present disclosure, it is intended that all matter contained in the drawings and specification be interpreted in an illustrative, and not a limiting, sense. Additional modifications, variations, and substitutions are contemplated in the foregoing disclosure. Accordingly, it is appropriate that the scope of the appended claims be broadly interpreted consistent with the scope of the present disclosure.

Claims

1. A filter medium, A fiber container, Open phase, and a fibrous container comprising a second phase on the open phase; an adsorbent in the fiber container; the open phase and the second phase each comprise thicker fibers and thinner fibers; A filter medium wherein the average diameter of the fibers in the open phase is greater than the average diameter of the fibers in the second phase.

2. 10. The filter medium of claim 1, wherein the average pore size of the open phase is greater than the average pore size of the second phase.

3. 3. The filter medium of claim 1 or 2, wherein the proportion of the thicker fibers in the open phase is less than or equal to the proportion of the thinner fibers in the open phase.

4. 10. A filter medium according to any one or more of the preceding claims, wherein the proportion of thicker fibres in the second phase is less than the proportion of thinner fibres in the second phase.

5. 10. A filter medium according to any one or more of the preceding claims, wherein the proportion of said thicker fibres in said open phase is greater than the proportion of said thicker fibres in said second phase.

6. 10. A filter medium according to any one or more of the preceding claims, wherein the proportion of finer fibres in the open phase is less than the proportion of finer fibres in the second phase.

7. 10. A filter medium according to any one or more of the preceding claims, wherein the thicker fibers are present in the open phase in an amount of 30 to 50 weight percent, based on the total fiber weight of the open phase.

8. 10. A filter medium according to any one or more of the preceding claims, wherein the thicker fibers comprise fibers of 15 to 20 denier.

9. 10. A filter medium according to any one or more of the preceding claims, wherein the finer fibers are present in the open phase in an amount of from 50 to 70 weight percent, based on the weight of fibers in the open phase.

10. 10. A filter medium according to any one or more of the preceding claims, wherein the finer fibers comprise fibers from 5 denier to less than 10 denier or fibers from 7 denier to less than 10 denier.

11. 10. A filter medium according to any one or more of the preceding claims, wherein the thicker fibers are present in the second phase in an amount of 10 to 20 weight percent, based on the weight of fibers in the second phase.

12. 10. A filter medium according to any one or more of the preceding claims, wherein the finer fibers are present in the second phase in an amount of 80 to 90 weight percent, based on the weight of fibers in the second phase.

13. 10. A filter medium according to any one or more of the preceding claims, wherein the thicker fibres comprise polyethylene terephthalate fibres.

14. 10. A filter medium according to any one or more of the preceding claims, wherein the finer fibres comprise polyethylene terephthalate fibres.

15. 10. The filter medium of any one or more of the preceding claims, wherein the fibrous container comprises adhesive in an amount greater than 0 weight percent and less than 10 weight percent, based on the total weight of the sorbent.

16. 15. The filter medium of any one or more of claims 1-14, wherein the fibrous container comprises less than 1 weight percent or 0 weight percent adhesive, based on the total weight of the sorbent.

17. 10. The filter medium of any one or more of the preceding claims, wherein the adsorbent comprises activated carbon particles, silica, zeolite, molecular sieves, clay, alumina, sodium bicarbonate, ion exchange resins, catalysts, or combinations thereof.

18. 18. The filter medium of claim 17, wherein the adsorbent comprises activated carbon particles, impregnated activated carbon particles, ion exchange resin, or a combination thereof.

19. 10. A filter medium according to any one or more of the preceding claims, further comprising a coating layer.

20. 20. The filter medium of claim 19, wherein the cover layer comprises spunbond fibers.

21. 21. The filter medium of claim 19 or 20, further comprising an adhesive, said adhesive being present only at the interface between said fibrous container and said cover layer.

22. 10. A filter medium according to any one or more of the preceding claims, having a thickness of 4.0 millimeters or less.

23. 10. A filter medium according to any one or more of the preceding claims, having a thickness of less than 2.5 millimeters.

24. 10. A filter medium according to any one or more of the preceding claims, wherein the filter medium is pleated.

25. 10. A gas adsorption filter comprising a filter medium according to any one or more of the preceding claims.

26. 10. A cabin air filter for a vehicle comprising a filter medium according to any one or more of the preceding claims.

27. 10. An air intake filter for a vehicle comprising a filter medium according to any one or more of the preceding claims.

28. 10. A heating, ventilation and air conditioning filter comprising a filter medium according to any one or more of the preceding claims.

29. 10. A filter medium according to any one or more of the preceding claims, forming the fiber container; providing the sorbent on the fiber container; and laminating the fibrous containers to form the filter medium.

30. 30. The filter medium of claim 29, wherein the process further comprises providing an adhesive on the fiber container after applying the sorbent on the fiber container.

31. 31. The filter media of claim 30, wherein the adhesive comprises a powder.

32. 32. The filter medium of claim 30 or 31, wherein the adhesive comprises a web.

33. 33. A filter medium according to any one or more of claims 30 to 32, wherein the adhesive is not present in a second phase.

34. 33. The filter medium of any one or more of claims 30-32, wherein less than 1 weight percent adhesive is present in the second phase, based on the total weight of the second phase.

35. 35. The filter medium of any one or more of claims 30-34, wherein forming the fibrous container comprises intermixing the thicker fibers and the thinner fibers in the open phase and the second phase.

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