A nonwoven array of porous hollow fibers, articles thereof, and methods of making such nonwoven arrays

Abstract

Described herein is a method of making a self supported nonwoven array of porous hollow fibers using a conformable resin. Such nonwoven arrays may find utility in evaporative cooling applications.

Description

PA103268W002A NONWOVEN ARRAY OF POROUS HOLLOW FIBERS, ARTICLES THEREOF, AND METHODS OF MAKING SUCH NONWOVEN ARRAYSTECHNICAL FIELD

[0001] An array of porous hollow fibers is held together with a conformable resin to provide a selfsupported array. A method of making the array is disclosed. Articles comprising these arrays may be used in evaporative applications or fluid scrubbing.SUMMARY

[0002] Porous hollow fiber woven materials are known in the art, wherein an array of porous hollow fiber is knitted together to form a web. Such materials may be used for humidification or dehumidification of gas, removal (or scrubbing) of a particular compound(s) from a fluid stream, evaporative cooling, etc.

[0003] One issue with these woven materials is that the knitting process is slow due to a second fiber being knitted around each of the individual porous hollow fibers across the array. Thus, an alternative process for making webs of porous hollow fibers was desired.

[0004] In one aspect, a nonwoven array is disclosed comprising: (a) a single layer of porous hollow fibers oriented parallel to one another in a first length direction; and (b) a strand of conformable resin provided in a second direction across the single layer of porous hollow fibers, wherein the strand is adhered to at least a portion of the outer surface of the porous hollow fibers, and wherein the nonwoven array is self-supported.

[0005] In another aspect, the nonwoven array as disclosed above is used in an evaporative cooling article.

[0006] In yet another aspect, a method of making a nonwoven array nonwoven array is disclosed. The method comprising: (a) providing a single layer of porous hollow fibers oriented axially in a first direction; (b) applying a conformable resin across the single layer in a second direction; and (c) hardening the conformable resin, resulting in a self-supported nonwoven array.

[0007] The above summary is not intended to describe each embodiment. The details of one or more embodiments of the invention are also set forth in the description below. Other features, objects, and advantages will be apparent from the description and from the claims.DESCRIPTION OF FIGURES

[0008] Fig. 1 is a top view of a nonwoven array according to one embodiment of the present disclosure;

[0009] Fig. 2 is a cross-sectional view of a nonwoven array according to one embodiment of the present disclosure;

[0010] Fig. 3 is a top view of a nonwoven array according to one embodiment of the present disclosure; and

[0011] Fig. 4 is a top view of a nonwoven array according to one embodiment of the present disclosure.

[0012] Repeated use of reference characters in the specification and drawings is intended to represent the same or analogous features or elements of the disclosure. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the disclosure. The figures may not be drawn to scale.DETAILED DESCRIPTION

[0013] As used herein, the term “a”, “an”, and “the” are used interchangeably and mean one or more; and “and / or” is used to indicate one or both stated cases may occur, for example A and / or B includes, (A and B) and (A orB).

[0014] Also herein, recitation of ranges by endpoints includes all numbers subsumed within that range (e.g., 1 to 10 includes 1.4, 1.9, 2.33, 5.75, 9.98, etc.).

[0015] Also herein, recitation of “at least one” includes all numbers of one and greater (e.g., at least 2, at least 4, at least 6, at least 8, at least 10, at least 25, at least 50, at least 100, etc.).

[0016] As used herein, “comprises at least one of’ A, B, and C refers to element A by itself, element B by itself, element C by itself, A and B, A and C, B and C, and a combination of all three.

[0017] The terms used to indicate the direction in the figures, such as ‘top; are relative terms, and may change based on a relative position of a viewer.

[0018] The nonwoven array of the present disclosure may be understood by reference to Fig. 1, which discloses one embodiment of the present disclosure. Shown in Fig. 1 is nonwoven array 10, which comprises a plurality of porous hollow fibers 12. The plurality of porous hollow fibers are oriented axially to one another in a single layer and in first direction, a, forming array 11. A strand of conformable resin 14 is provided across array 11 in second direction, b.

[0019] The porous hollow fibers disclosed herein are fibers comprising a lumen, or hollow cavity, which fluidly connects one terminal end of the fiber to the other terminal end.

[0020] In some embodiments, the porous hollow fibers have an average outer diameter of at least 200, 250, or even 300 micrometers and at most 250, 300, 350, 400, or even 500 micrometers. In some embodiments, the porous hollow fibers have an average inner diameter of the lumen of at least 150, 175, or even 200 micrometers and at most 225, 250, 280, 300, or even 350 micrometers.

[0021] The porous hollow fibers are long, having an average length of at least 10, 50, 100, or even 500 centimeters (cm). In some embodiments, the porous hollow fibers are wound upon a spool due to their long lengths.

[0022] The hollow fibers disclosed herein are also porous, enabling fluid (e.g., gas) to pass from the inner lumen of the fiber to the outer surface of the fiber or visa versa. The pore size may be characterized by techniques known in the art, including scanning electron microscopy, gas permeation, or bubbe pointmeasurements. In some embodiments, the porous hollow fibers are microporous, having an average pore size of at least 0.01, 0.02, or even 0.03 micrometers and at most 0.04, 0.06, 0.08, 0.1, 0.15, or even 0.2 micrometers. In some embodiments, the porous hollow fibers have an average bubble point of at least 150, 175, or even 200 pounds per square inch (psi) and at most 220, 240, 250, 275, or even 300 psi. Generally, the porous hollow fiber disclosed herein have high porosity, for example, at least 20, 25, 30, 25, 40, 45, 50, 60, or even 70% porosity and typically at most 80 or even 85%. Porosity herein refers to the void volume fraction of the fiber and is defined as the volume of the pores divided by the total volume of the fiber.

[0023] The porous hollow fibers are polymeric, derived from polymers such as polyolefins (e.g., polypropylene, polyethylene, polymethyl pentene or poly (4-methyl-l -pentene)), poly sulfone, cellulose acetate, polyethersulfone, or polyvinulidene fluoride (PVDF). In some embodiments, the porous hollow fibers are hydrophobic, meaning their surface has a water contact angle of 90 degree or higher.

[0024] Porous hollow fibers can be made via a dry-stretch process such as described in U. S. Pat. No. 9,541,302 (Taylor et al.) and U. S. Pat. Publ. No. 2024 / 0373592 (Borker et al.). Commercially available membranes comprising porous hollow fibers include those under the trade designation “STERAPORE” are available from Mitsubishi Chemical Corporation, Chiyoda City, Japan; or “3M LIQUI-CEL MM SERIES MEMBRANE CONTRACTOR” from Solventum Corporation, Maplewood, MN.

[0025] The conformable resin of the present disclosure is a polymeric resin that conforms to at least a portion of the outer surface of the porous hollow fiber as shown in Fig. 2. Fig. 2 is a cross-section of a nonwoven array according to one embodiment of the present disclosure. Conformable resin 24 contacts a portion of the outer surface of porous hollow fiber 22, which comprises lumen 23. Conforming of the resin to the outer surface of the porous hollow fiber can enable mechanical adherence between the resin and the fiber. The conformable resin may be deposited onto the porous hollow fibers in a viscous state, such that the resin forms around a portion of the outer surface of the porous hollow fiber. In some embodiments, the resin is firm, but still malleable, such that when the layer of porous hollow fibers and resin are pressed together (e.g., through a nip) the resin conforms to a portion of the surface of the porous hollow fibers, which may aid in controlling adhesion between the porous hollow fibers and the resin.

[0026] The conformable resin may comprise a thermoplastic, a thermoset, an elastomer, or combinations thereof.

[0027] In some embodiments, more than one different conformable resin is used.

[0028] A thermoplastic is a material known in the art, which when heated above its glass transition temperature becomes pliable, solidifies upon cooling, and can be reheated and reshaped without losing its strength. Exemplary thermoplastics include: polyolefins such as polypropylene and polyethylene.

[0029] A thermoset is a material known in the art, which can be a soft solid that is irreversibly hardened after undergoing a chemical reaction. Generally, these materials are cured either through heat, radiation, or a catalyst. Exemplary thermosets include:polyester, nylon, and poly imide.

[0030] An elastomer is a material known in the art, which can be a soft solid that is irreversibly hardened after undergoing a chemical reaction. An elastomer differs from a thermoset, in that it exhibits elastic properties, such as stretch. Exemplary elastomers include: natural rubber, polyurethane, and polybutadiene.

[0031] In some embodiments, the conformable resin comprises an additive such as a biocide, an antioxidant, a UV-resistant agent, hindered amine light stabilizers (HALS), or colorants. In some embodiments, the conformable resin comprises less than 70, 60, 50, 40, 30, 25, 20, 15, 10, or even 5% by weight of the additive.

[0032] In some embodiments, the conformable resin is adhesively adhered to at least a portion of the outer surface of the porous hollow fibers.

[0033] A strand of conformable resin is provided in a direction different from the orientation of the porous hollow fiber length.

[0034] As shown in Fig. 1, the direction of the strand of conformable resin (b) is perpendicular to the direction of the porous hollow fiber length (a). In some embodiments, the direction of the strand is at least 5, 10, 15, or even 20 degrees from the direction of the porous hollow fiber length. In some embodiments, the direction of the strand is at most 90, 75, 50, 40, or even 30 degrees from the direction of the porous hollow fiber length. For example, in Fig. 3 strand 34 is 45 degrees from the direction of the porous hollow fiber length. The strand may have a tortuous random configuration, a semi random pattern, a sinusoidal pattern, or other such configuration. In some embodiments, the strand is patterned across the layer of porous hollow fibers. In some embodiments, the strand is random across the layer as shown in Fig. 4, where strand 44 is disposed on top of the layer of porous hollow fibers 42.

[0035] In some embodiments, more than one type of strand of conformable resin is used.

[0036] In some embodiments, the distance between adjacent porous hollow fibers in the array is at least 200, 250, 300, 400, or even 500 micrometers and at most 2000, 1800, 1500, 1200, 1000, 750 or even 600 micrometers from axis to axis.

[0037] The conformable resin holds the plurality of porous hollow fibers in place, but should not substantially inhibit the performance of the porous hollow fibers. In some embodiments, fluid is passed through the lumens of the porous hollow fibers and then components of interest (e.g., water vapor, or carbon dioxide) diffuse from the lumen into the pores of the fiber. Thus, the conformable resin should not compromise the lumen (in other words, fluid (e.g., liquid) needs to be able to flow unencumbered from one terminal end of the hollow fiber to the other terminal end without restrictions). Further, the conformable resin should not introduce perforations through the porous hollow fibers walls, wherein when water is run through the lumen, no water should leak through the fiber walls. Still further, because the pores are used (for example for evaporate cooling or removal of an analyte) it is advantageous that covering or blocking of the pores by the conformable resin is minimized. Preferably, the conformable resin does not completely enclose the circumference of the porous hollow fiber. As shown in Fig. 2, in some embodiments, the conformable resin is located on a top surface of the layer of the porous hollowfibers and the bottom surface of the layer is substantially free (i.e., less than 5, 2, 1, or even 0.5% by area) of conformable resin. In some embodiments, at least 1, 2, 5, 8, or even 10 % and at most 50, 40, 30, 25, 20, 15, or even 10% of the surface area of the single layer of porous hollow fibers is covered by the conformable resin.

[0038] In some embodiments, multiple layers of the nonwoven arrays may be layered on top of one another for use. Thus, in some embodiments, the height of the strand on top of the porous hollow fibers (designated by c in Fig. 2) may be controlled to act as a spacer between adjacent layers of nonwoven. In some embodiments, when viewed cross-sectionally, at an apex of the porous hollow fibers, a height of the strand (c) from the apex is at least 0.05, 0.8, 0.1, 0.15, 0.2, 0.25, or even 0.3 mm and at most 1, 0.8, 0.6, 0.5, or even 0.4 mm, preferably between 0.1 and 0.5 mm.

[0039] In some embodiments, the nonwoven array consists essentially of the single layer of porous hollow fibers and the strand of conformable resin, meaning that the nonwoven array is free of any additional elements other than the porous hollow fibers and the conformable resin, which would help support the nonwoven array (for example, a frame). In some embodiments, the nonwoven array consists of the single layer of porous hollow fibers and the strand of conformable resin.

[0040] The nonwoven arrays of the present disclosure may be made by arranging a plurality of porous hollow fibers in a single layer making sure the porous hollow fibers are parallel to one another lengthwise as shown in Fig. 1. Then, a conformable resin is disposed across the layer of porous fibers and then hardened.

[0041] In some embodiments, the conformable resin is extruded as a strand onto the layer of porous hollow fibers. Upon cooling, the extruded resin hardens. Care should be taken so that the extrudate is not so hot that it melts the porous hollow fibers. In some embodiments, the conformable resin is applied at a temperature lower than a melting point of the hollow porous fiber. Preferably, the conformable resin is applied at a temperature that does not trigger a dimensional change in the porous hollow fiber, such as shrinkage (volume contraction).

[0042] In some embodiments, the conformable resin is a curable resin that is applied onto the layer of porous hollow fibers and then cured to harden the resin. For example, the curable resin is exposed to actinic radiation such as ultraviolet or e-beam radiation to chemically react the curable resin.

[0043] Advantageously, the method of the present disclosure may be made in a continuous or web-based process, wherein the porous hollow fibers are aligned lengthwise in the machine direction with the conformable resin applied across the fibers. In another embodiments, the porous hollow fibers are aligned lengthwise in the cross-machine direction with the conformable resin applied in the machine direction.

[0044] In some embodiments, the array of porous fibers comprising the conformable resin is passed through a nip to create a uniform thickness of the web.

[0045] The conformable resin holds the array of porous hollow fibers in place, creating a self-supported nonwoven. As used herein, self-supported refers to the ability of the nonwoven array to be handled and not fall apart. In some embodiments, the nonwoven array is stiff, meaning that when the porous hollowfibers in the nonwoven array is held on one end horizontal to the ground, the nonwoven array is able to remain parallel to the ground. It has also been discovered that advantageously, the conformable resin prevents the porous hollow fibers from slipping within the article as is common when the porous hollow fibers are knitted together with a yam in a woven material.

[0046] The nonwoven arrays disclosed herein may be useful in evaporative cooling, O2 scrubbing, Greenhouse gas scrubbing, SOXscrubbing, NOXscrubbing, HCL scrubbing, Ammonia scrubbing, Humidification of gas, Dehumidification of gas, Liquid desiccant absorption of moisture and latent heat for energy recovery in HVAC systems, Air emission control (of noxious odors — such as at pig or hog farms), and / or Gas temperature control by varying the humidity level (such as in evaporative cooling or in a swamp cooler).

[0047] In one exemplary use of the nonwoven arrays disclosed herein, the nonwoven array is connected to multiple fluid ports, for example, four fluid ports: an inlet for introducing the first fluid, an outlet for discharging the first fluid, an inlet for introducing the second fluid, and an outlet for discharging the second fluid. A first fluid can be run through the lumens of the array, while the second fluid contacts the outside of the porous hollow fibers. The first and second fluids do not mix and the only transfer that occurs happens through the porous walls on the fibers. The pores in the fiber wall are normally filled lib a stationary layer of one of the two fluids, the other fluid being excluded from the pores due to surface tension and / or pressure differential effects. Mass transfer and separation are usually caused by diffusion, which is driven by the difference in concentration of the transferring species between the two phases. Typically, no convective or bulk flow occurs across the membrane.

[0048] In the case of gas / liquid separations, rmcroporous hydrophobic hollow fibers are used. Since the fibers are h drophobic and have very small pores, liquids with high surface tension, such as water, will not easily pass through the pores. The nonwoven array acts as an inert support that brings the liquid and gas phases into direct contact, without dispersion. The mass transfer between the two phases is typically governed by the difference in partial pressure of the gas species being transferred.

[0049] For liquid systems, the liquid / quid interface at each pore is typically immobilized by the appropriate selection of fiber and liquid phase pressures. In this case, the porous hollow fibers also act as an inert support to facilitate direct contacting of two immiscible phases without mixing.

[0050] In some embodiments, the nonwoven array comprises at least 20, 30, or even 40 fibers per meh. In some embodiments, the nonwoven array comprises at most 50, 60, or even 70 fibers per inch.

[0051] In some embodiments, the nonwoven array is layered or wound around itself to form an article. In some embodiments, adjacent layers of the nonwoven array are at least 100, 200, 300, or even 400 micrometers apart. In some embodiments, adjacent layers of the nonwoven array are at most 500, 750, 1000, 1500, or even 2000 micrometers apart.

[0052] Many technologies or industries have the need to remove, add or control heat, cold, or humidity in or from gasses, to remove, add or control dissolved gasses in or from liquids, to remove, add or control a gas or material in or from a gas, to remove, add or control a liquid or solvent in or from a liquid, toremove, add or control a liquid or solvent in or from a gas, or the like. In some embodiments, the nonwoven arrays disclosed herein can be used in removal of contaminants from an effluent stream or in evaporative cooling applications.EXAMPLES

[0053] Unless otherwise noted, all parts, percentages, ratios, etc. in the examples and the rest of the specification are by weight, and all reagents used in the examples were obtained, or are available, from general chemical suppliers such as, for example, Sigma-Aldrich Company, Saint Louis, Missouri, or may be synthesized by conventional methods.

[0054] The following abbreviations are used in the Example Section: g = gram, um = micron = micrometer, cc = cubic centimeter, min = minute, hr = hour, % = percent, rpm = revolution per minute, rev = revolution, ml = milliliter, gsm = gram per square meter, fpm = feet per min, mil = 1 / 1000thof an inch, psi = pounds per square inch, MPa = mega Pascal, OD = outer diameter, and ID = inner diameter. Table 1 MaterialsAbbreviation DescriptionPP Polypropylene primarily composed of isotactic polypropylene repat units with random ethylene distribution available under the trade designation “VISTAMAXX 6902 NAT” from ExxonMobil, Houston, TX, with a density of 0.869 g / cc.Epoxy Available under the trade designation “3M Epoxy DP 100+” from 3M Co., Maplewood, MNFibers Polypropylene porous hollow fibers similar to those disclosed in U. S.Pat. No. 9,541,302 and U. S. Pat. Publ. No. 2024 / 0373592

[0055] Test Methods

[0056] Test Method 1: Thickness and width measurements

[0057] The width of the conformable strand and the thickness of the nonwoven array were measured using a handheld digital handheld gage (Mitutoyo America Corp., Aurora, IL). The average result for the strand width and nonwoven array thickness was reported.

[0058] Test Method 2: Water leak test

[0059] To confirm that the porous hollow fibers were not damaged by the extrusion of the PP, the samples (a section about 4 inch (10.2 cm) long, containing 6 to 12 porous hollow fibers) were assembled with fittings to create a mini-module as follows. The terminal ends from one side of the fiber array were placed into a 0.25 inch (6.4 mm) OD nylon tubing, cut to a length of 1.0 to 1.5 inch (25 to 38 mm). This process was repeated with the terminal ends on the other side of the fiber array. Each end was potted using Epoxy. Once the epoxy had hardened (after about 12 hr), the outside edge of each nylon tube was cut using a sharp razor blade to expose the epoxy potted fibers. This formed a mini-module, which consisted of an array of fibers about 4 inches (10.16 cm) long with epoxy caps on both ends to insert into test equipment.

[0060] Two mini-modules were made for each Example and Comparative Example. A syringe pump was used to inject reverse osmosis water through the array at one epoxy capped side at a volumetric rate of 20 ml / min. Water pressure was maintained between 6 and 16 psi (41.4 and 110.3 MPa) with fiber leaks generally more visible at higher water pressures. If there was significant damage to the porous hollow fibers, a water leak, would be visible as manifested by a spray of water or the formation of beads of water on the outside of the porous hollow fibers.

[0061] Each mini-module was tested for about 1 min.

[0062] Test Method 3: Nonwoven array stiffness

[0063] A section of the sample about 8 inch by 10 inch (203 mm by 254 mm) was evaluated. The sample was supported on a flat horizontal surface with the length of the porous hollow fibers being perpendicular to the edge of the surface. A one inch (25.4 mm) long section of sample was pushed over the edge of the surface so that it was no longer supported and was evaluated for its stiffness. If the unsupported portion of the sample draped down the vertical surface it would have an angle of 90 degrees. If the unsupported sample maintained its horizontal position, it would have a 0 degree angle from the horizontal direction.

[0064] Test Method 4: Basis weight (BW)

[0065] Basis weight was calculated by dividing the sample weight by the surface area. Sample weight of the array of fibers was measured before and after the addition of the cross strands, which for the examples was the PP strands and for the comparative examples was the warp yam. The strand basis weight (or warp yam basis weight) is the difference between the array of fibers with and without the cross strands. The percentage strand or warp yam basis weight is calculated by the strand basis weight (or warp yam basis weight) divided by the final basis weight of the sample multiplied by 100%.

[0066] Comparative Example 1 (CE 1)

[0067] Comparative Example 1 was a knitted porous hollow fiber mat from the 3M LIQUI-CEL series available from Solventum Corp., Maplewood, MN, with fibers having an OD of about 300 pm and ID of about 230 pm, and with a fiber spacing of about 35 fibers per inch. The sample was tested according to Test Methods 2, 3, and 4 and the results are shown in Table 2 below.

[0068] Comparative Example 2 (CE 2)

[0069] Comparative Example 2 was a knitted porous hollow fiber mat from the 3M LIQUI-CEL series, with an OD of about 300 pm and ID of about 230 pm, and with a fiber spacing of about 20 fibers per inch. The sample was tested according to Tests 2, 3, and 4 and the results are shown in Table 2 below.

[0070] Example 1 (EX 1)

[0071] A nonwoven array with fibers similar in dimension and spacing to Comparative Example 1 was made. The Fibers had an OD of about 300 pm and ID of about 230 pm.

[0072] Method of making an array of fibers: Two pieces of double-sided tape were applied onto a sheet of paper stock about 8.0 inches (203 mm) distance apart. The Fibers where manually placed on top of the double-sided tape with a spacing of about 35 fibers per inch such that the two pieces of double sided tape held down the two ends of the fibers.

[0073] Extruding polypropylene strands onto the array of fibers: Strands of PP were extruded onto the positioned array of fibers using a single screw 1.25 in (32 mm) diameter extruder (Davis-Standard, Chicago, IL) with a die temperature set to 140°C. The die tip was made of a single row of holes of a diameter of about 1.1 mm, spaced every 0.5 inch (12.7 mm). The distance between the die and nip roll was set to 3.5 inch (76.2 mm). The pump (2.92 rev / cc) speed was set to 35 rpm, for an overall polymer rate of about 89 g / min.

[0074] The array of fibers was run at a line speed of 30 fpm under the die to deposit PP strands onto the porous hollow fibers and then run through the nip roll having a gap of 40 mil (1 mm). Samples were created with various line speed and nip pressure. Once the PP strands had solidified on top of the array of fibers, the edges of the array including the double-sided tape adhered to the stock paper were cut off producing a self-supported nonwoven array that included only the array of fibers with the PP strand atop.

[0075] The nonwoven array comprising 12 porous hollow fibers was tested according to Test Methods 1, 2, and 4 and the results are shown in Table 2 below. Test 2 was run at both 7 and 16 psi and no leaks were observed.

[0076] Example 2 (EX 2)

[0077] A nonwoven array was prepared similar to Example 1 except for the following: the extrusion process was performed at 15 fpm instead of 30 fpm.

[0078] The nonwoven array comprising 9 porous hollow fibers was tested according to Test Methods 1, 2, and 4 and the results are shown in Table 2 below. Test 2 was run at both 10 and 12 psi and no leaks were observed.

[0079] Example 3 (EX 3)

[0080] A nonwoven array was prepared similar to Example 1 except for the following: the extrusion process was performed at 25 fpm instead of 30 fpm with a nip roll gap of 20 mil (0.5 mm).

[0081] The nonwoven array comprising 6 porous hollow fibers was tested according to Test Methods 1, 2, and 4 and the results are shown in Table 2 below. Test 2 was run at 6 psi and no leaks were observed.

[0082] Example 4 (EX 4)

[0083] A nonwoven array was prepared similar to Example 1 except for the following: the extrusion process was performed at 20 fpm instead of 30 fpm.

[0084] The nonwoven array was tested according to Test Methods 1, 3, and 4 and the results are shown in Table 2 below.

[0085] Example 5 (EX 5)

[0086] A nonwoven array was prepared similar to Example 1 except for the following: the extrusion process was performed at 10 fpm instead of 30 fpm with a nip roll gap of 30 mil (0.76 mm).

[0087] The nonwoven array was tested according to Test Methods 1, 3, and 4 and the results are shown in Table 2 below.Table 2CE 1 CE 2 Ex 1 Ex 2 Ex 3 Ex 4 EX 5 Line Speed (fpm) 30 15 25 20 10 Nip roll gap (mil) 40 40 20 40 30 Strand width (mm) 1.1 1.9 1.45 1.45 2.6 Nonwoven thickness (mm) 0.54 0.58 0.41 0.6 0.58 Water Leakage none none none none none NT NT Stiffness (bending angle in 90 90 NT NT NT ~0 ~0 degrees)Final BW (gsm) 25.5 15.8 35.5 31.8 30.7 36.5 30.7 Strand or warp yam BW (gsm) 4.5 4.2 25.5 44.4 26.4 34 65.3 Strand or warp yam BW(%) 15 21 41.8 58.3 46.2 48.2 68NT= not tested

[0088] Foreseeable modifications and alterations of this invention will be apparent to those skilled in the art without departing from the scope and spirit of this invention. This invention should not be restricted to the embodiments that are set forth in this application for illustrative purposes. To the extent that there is any conflict or discrepancy between this specification as written and the disclosure in any document mentioned or incorporated by reference herein, this specification as written will prevail.

Claims

What is claimed is:

1. A nonwoven array comprisinga single layer of porous hollow fibers oriented parallel to one another in a first length direction; anda strand of conformable resin provided in a second direction across the single layer of porous hollow fibers, wherein the strand is adhered to at least a portion of the outer surface of the porous hollow fibers, andwherein the nonwoven array is self-supported.

2. The nonwoven array of claim 1, wherein the single layer of porous hollow fibers has a distance of at least 200 micrometer to at most 2000 micrometers between adjacent porous hollow fibers.

3. The nonwoven array of any one of the previous claims, wherein the porous hollow fibers have an average pore size of at least 0.03 micrometers to at most 0.1 micrometers.

4. The nonwoven array of any one of the previous claims, wherein the porous hollow fibers have a lumen with an inner diameter of at least 175 micrometer and at most 350 micrometers.

5. The nonwoven array of any one of the previous claims, wherein the porous hollow fibers have an outer diameter of 300 to 400 micrometers.

6. The nonwoven array of any one of the previous claims, wherein the porous hollow fibers comprise a polyolefin or polysulfone, cellulose acetate, polyethersulfone, polyvinulidene fluoride (PVDF), or combinations thereof.

7. The nonwoven array of any one of the previous claims, wherein the porous hollow fibers are hydrophobic.

8. The nonwoven array of any one of the previous claims, wherein the porous hollow fibers have an average length of at least 10 cm.

9. The nonwoven array of any one of the previous claims, wherein the porous hollow fibers have an average length of at least 100 cm.

10. The nonwoven array of any one of the previous claims, wherein the strand is mechanically adhered to at least a portion of the outer surface of the porous hollow fibers.

11. The nonwoven array of any one of the previous claims, wherein the strand is adhesively adhered to at least a portion of the outer surface of the porous hollow fibers.

12. The nonwoven array of any one of the previous claims, wherein the conformable resin comprises a polymer.

13. The nonwoven array of any one of the previous claims, wherein the conformable resin comprises a thermoplastic, a thermoset, an elastomer, or combinations thereof.

14. The nonwoven array of any one of the previous claims, wherein the conformable resin comprises a biocide, anti-oxidant, a UV-resistant agent, HALS, colorant, or combinations thereof.

15. The nonwoven array of any one of the previous claims, wherein less than 1% and at most 50% of the surface area of the single layer of porous hollow fibers is covered by the strand of conformable resin.

16. The nonwoven array of any one of the previous claims, wherein at most 20% of the surface area of the single layer of porous hollow fibers is covered by the strand of conformable resin.

17. The nonwoven array of any one of the previous claims, wherein the nonwoven array comprises a first strand and a second strand, wherein the first and second strands are different.

18. The nonwoven array of any one of the previous claims, wherein the second direction is at least 5 degrees and at most 90 degrees from the first direction.

19. The nonwoven array of any one of the previous claims, wherein the second direction is patterned.

20. The nonwoven array of any one of the previous claims, wherein the second direction is random.

21. The nonwoven array of any one of the previous claims, wherein the strand of conformable resin does not encapsulate a circumference of the porous hollow fibers.

22. The nonwoven array of any one of the previous claims, wherein the nonwoven array comprises a first major outer surface and an opposing second major outer surface, wherein the first major outer surface comprises the conformable resin and the opposing second major outer surface is substantially free of the conformable resin.

23. The nonwoven array of any one of the previous claims, wherein the nonwoven array consists essentially of the single layer of porous hollow fibers and the strand of conformable resin.

24. The nonwoven array of any one of the previous claims, wherein for each porous hollow fiber, the two terminal ends are fluidly connected via a lumen.

25. The nonwoven array of any one of the previous claims, wherein the nonwoven array when tested per Test Method 2 at 10 psi shows no leaks.

26. The nonwoven array of any one of the previous claims, wherein when viewed cross-sectionally, at an apex of the porous hollow fibers, a height of the strand from the apex is at least 0.05 mm and at most 1 mm.

27. An evaporative cooling article comprising the nonwoven array according to any one of the previous claims.

28. The article of any one of claims 27 comprising multiple layers of the nonwoven array, wherein adjacent layers of the nonwoven array are 200 to 2000 micrometers apart.

29. A method of making a nonwoven array, the method comprising(a) providing a single layer of porous hollow fibers oriented axially in a first direction;(b) applying a conformable resin across the single layer in a second direction; and(c) hardening the conformable resin, resulting in a self-supported nonwoven array.

30. The method of claim 29, wherein the conformable resin is extruded onto the single layer of porous hollow fibers.

31. The method of any one of claims 29-30, wherein when the conformable resin contacts the single layer of porous hollow fibers, the conformable resin has a temperature lower than a melting point of the hollow porous fiber.

32. The method of any one of claims 29-31, wherein the conformable resin is a resin curable by actinic radiation.

33. The method of any one of claims 29-31, wherein the hardening is by exposing to actinic radiation.

34. The method of any one of claims 29-31, wherein the hardening is by cooling.

35. The method of any one of claims 29-34, wherein the array of porous hollow fibers is in the machine direction.

36. The method of any one of claims 29-34, wherein the array of porous hollow fibers is in the cross-machine direction.

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