Absorbent substrate for absorbing different fluids

Abstract

Absorbent articles are disclosed that, in one embodiment, can comprise feminine hygiene products. The absorbent articles can include a multi-layer absorbent substrate. The absorbent substrate contains a retention layer comprised of superabsorbent material and resilient fibers. The ratio between the superabsorbent material and the resilient fibers is controlled so as to produce an absorbent substrate that is well suited for absorbing not only urine but also more viscous fluids such as menses.

Description

[0001] 65127350PCT02 KCX-2167-PCT

[0002] ABSORBENT SUBSTRATE FOR ABSORBING DIFFERENT FLUIDS

[0003] CROSS-REFERENCE TO RELATED APPLICATION

[0004] The present application is related and has right of priority to U. S. Provisional Patent Application No. 63 / 738,024 filed on December 23, 2024, which is incorporated by reference in its entireties for all purposes.

[0005] BACKGROUND

[0006] Personal care products, such as diapers, diaper pants, training pants, adult incontinence products, and feminine care products, can include absorbent structures that are intended to provide various functional characteristics. For example, absorbent structures in such products are intended to intake body exudates quickly and distribute the exudates to an absorbent core or body that is capable of storing an adequate volume of exudates and prevent such stored exudates in the absorbent core from exiting the absorbent core and transferring to other layers of the product and / or against the user’s skin or clothing. Personal care products must also be considerate of other user perceived benefits such as comfort and discreteness, which can be impacted by absorbent structure properties such as thickness, stiffness, and weight.

[0007] Absorbent structures can contain a superabsorbent material. Superabsorbent materials can be configured in the form of particles including fibers and are commonly utilized in substrates for increased absorbent capacity.

[0008] In many applications, the personal care products must be designed to absorb different fluids that have different characteristics. For instance, urine and menses or urine and BM can have different viscosities and different absorbency characteristics. Designing a personal care product that can efficiently absorb two different fluids with two different characteristics is challenging.

[0009] In view of the above, a need currently exists for an absorbent substrate and a personal care product containing the absorbent substrate that can absorb two different types of fluids, such as urine and menses. In addition, a need currently exists for an absorbent structure and product containing the absorbent structure that can absorb two different types of fluids and yet be relatively thin.

[0010] SUMMARY

[0011] In general, the present disclosure is directed to an absorbent article and / or an absorbent substrate that has enhanced fluid control properties. For instance, the present disclosure is directed to a unitary absorbent substrate that displays excellent absorbent performance when contacted with fluids having different characteristics, such as being contacted by either urine or menses. The absorbent substrate can comprise a multi-layered material that can include an intake layer, a retention layer, and optionally a distribution layer. The retention layer contains a superabsorbent material in65127350PCT02 KCX-2167-PCT

[0012] combination with resilient fibers. In accordance with the present disclosure, the superabsorbent particles are combined with resilient fibers in a way that produces a spaced-apart relationship optimal for absorbing relatively high viscosity fluids and relatively low viscosity fluids, such as urine and menses.

[0013] In one embodiment, for instance, the present disclosure is directed to an absorbent substrate comprising an intake layer, a retention layer, and a distribution layer. The retention layer can be disposed between the intake layer and the distribution layer. In accordance with the present disclosure, the absorbent substrate displays a third intake of less than about 100 seconds when tested according to the FIUP Test at 25 mL per insult and wherein the absorbent substrate has a menses intake of less than 20 seconds when tested according to the Heated Intake Test. In addition, the absorbent substrate can display a rewet of less than about 1 g when tested according to the FIUP Test at 8 mL per insult or at 25 mL per insult.

[0014] In one aspect, the retention layer includes resilient fibers blended with a superabsorbent material. The resilient fibers, for instance, can comprise cellulose fibers, such as crosslinked cellulose fibers or regenerated cellulose fibers. Alternatively, the resilient fibers can comprise synthetic fibers such as polyester fibers, polylactic acid fibers, polyhydroxyalkanoate fibers, or polypropylene fibers. In accordance with the present disclosure, a weight ratio of the resilient fibers to superabsorbent material can be between about 0.25 and about 0.59, such as between about 027 and about 0.55. In one aspect, the superabsorbent material spacing in the retention layer is between about 480 microns to about 1,300 microns, such as from about 550 microns to about 1,300 microns. The packing density can be from about 0.02 to about 0.055. In one aspect, the superabsorbent material contained in the retention layer has a basis weight of at least about 175 gsm, such as at least about 180 gsm, such as at least about 190 gsm. The absorbent substrate can have a basis weight of between about 250 gsm to about 1,500 gsm, such as from about 250 gsm to about 900 gsm.

[0015] In one embodiment, the absorbent substrate is foam formed. For instance, the different layers can be formed during the same process such that there is fiber mixing between the adjacent layers. For example, at least some fibers in the intake layer can be mixed with at least some fibers in the retention layer and at least some fibers in the retention layer can be mixed with at least some fibers in the distribution layer.

[0016] The intake layer can be comprised of synthetic polymer fibers, such as polyester fibers, combined with binder fibers, such as bi-component binder fibers. The binder fibers can be present in the intake layer in an amount from about 30% by weight to about 75% by weight, such as in an amount from about 40% by weight to about 65% by weight. The basis weight of the intake layer can be from about 25 gsm to about 65 gsm, such as from about 30 gsm to about 60 gsm.65127350PCT02 KCX-2167-PCT

[0017] The distribution layer can comprise binder fibers combined with cellulose fibers. The binder fibers can be present in the distribution layer in an amount from about 10% by weight to about 55% by weight, such as in an amount from about 25% by weight to about 50% by weight. The cellulose fibers can comprise pulp fibers, such as softwood fibers, optionally combined with crosslinked cellulose fibers. The basis weight of the distribution layer can be from about 15 gsm to about 65 gsm, such as from about 20 gsm to about 50 gsm.

[0018] The absorbent substrate of the present disclosure can be incorporated into any suitable absorbent article or personal care product. In one particular embodiment, the absorbent article can comprise a feminine care product, such as a feminine care pad

[0019] Other features and aspects of the present disclosure are discussed in greater detail below.

[0020] BRIEF DESCRIPTION OF THE DRAWINGS

[0021] A full and enabling disclosure of the present disclosure is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:

[0022] FIG. 1 is a plan view with cutaway portions of one embodiment of an absorbent article made in accordance with the present disclosure;

[0023] FIG. 2 is a side plan view of an exemplary multi-layer absorbent material including three layers according to one embodiment of the present disclosure;

[0024] FIG. 3 is a process schematic of an exemplary apparatus and associated method for forming a multi-layer absorbent material;

[0025] FIG. 4 is a detailed view of the headbox, headbox inputs, and resultant slurry from the headbox of FIG. 4; and

[0026] FIG. 5 is a side plan view of an alternative apparatus and associated method that can be used for forming a multi-layer absorbent material.

[0027] Repeat use of reference characters in the present specification and drawings is intended to represent the same or analogous features or elements of the present invention.

[0028] DEFINITIONS

[0029] As used herein, the term “foam formed product” means a product formed from a suspension including a mixture of a solid, a liquid, and dispersed gas bubbles.

[0030] As used herein, the term “foam forming process” means a process for manufacturing a product involving a suspension including a mixture of a solid, a liquid, and dispersed gas bubbles.

[0031] As used herein, the term “foaming fluid” means any one or more known fluids compatible with the other components in the foam forming process. Suitable foaming fluids include, but are not limited to, water.65127350PCT02 KCX-2167-PCT

[0032] As used herein, the term “foam half life” means the time elapsed until the half of the initial frothed foam mass reverts to liquid water.

[0033] As used herein, the term “layer” refers to a structure that provides an area of a substrate in a height direction of the substrate that is comprised of similar components and structure. There may be some mixing of fiber between adjacent layers.

[0034] As used herein, the term "nonwoven web" means a web having a structure of individual fibers or threads which are interlaid, but not in an identifiable manner as in a knitted web.

[0035] As used herein, unless expressly indicated otherwise, when used in relation to material compositions the terms "percent", “%”, "weight percent", or "percent by weight" each refer to the quantity by weight of a component as a percentage of the total except as whether expressly noted otherwise.

[0036] The term “absorbent article” refers herein to an article intended and / or adapted to be placed against or in proximity to the body (i.e., contiguous with the body) of the wearer to absorb and contain various liquid, solid, and semi-solid exudates discharged from the body. Examples include, but are not limited to, diapers, diaper pants, training pants, youth pants, swim pants, feminine hygiene products, including, but not limited to, menstrual pads or pants, incontinence products, medical garments, surgical pads and bandages, and so forth.

[0037] The term ''superabsorbent material" as used herein refers to water-swellable, water-insoluble organic or inorganic materials including superabsorbent polymers and superabsorbent polymer compositions capable, under the most favorable conditions, of absorbing at least about 10 times their weight, or at least about 15 times their weight, or at least about 25 times their weight in an aqueous solution containing 0.9 weight percent sodium chloride.

[0038] The term "machine direction" as used herein refers to the direction of travel of the forming surface onto which fibers are deposited during formation of a nonwoven web.

[0039] The term "cross-machine direction" as used herein refers to the direction which is perpendicular to both the machine direction and the height direction defined above.

[0040] The term "pulp" as used herein refers to fibers from natural sources such as woody and non-woody plants. Woody plants include, for example, deciduous and coniferous trees. Non-woody plants include, for example, cotton, flax, esparto grass, milkweed, straw, jute, hemp, and bagasse. Pulp fibers can include hardwood fibers, softwood fibers, and mixtures thereof.

[0041] The term "average fiber length" as used herein refers to an average length of fibers, fiber bundles and / or fiber-like materials determined by measurement utilizing microscopic techniques. A sample of at least 20 randomly selected fibers is separated from a liquid suspension of fibers. The fibers are set up on a microscope slide prepared to suspend the fibers in water. A tinting dye is added65127350PCT02 KCX-2167-PCT

[0042] to the suspended fibers to color cellulose-containing fibers so they may be distinguished or separated from synthetic fibers. The slide is placed under a Fisher Stereomaster II Microscope--S19642 / S19643 Series. Measurements of 20 fibers in the sample are made at 20X linear magnification utilizing a 0-20 mils scale and an average length, minimum and maximum length, and a deviation or coefficient of variation are calculated. In some cases, the average fiber length will be calculated as a weighted average length of fibers (e.g., fibers, fiber bundles, fiber-like materials) determined by equipment such as, for example, a Kajaani fiber analyzer Model No. FS-200, available from Kajaani Oy Electronics, Kajaani, Finland. According to a standard test procedure, a sample is treated with a macerating liquid to ensure that no fiber bundles or shives are present. Each sample is disintegrated into hot water and diluted to an approximately 0.001% suspension. Individual test samples are drawn in approximately 50 to 100 ml portions from the dilute suspension when tested using the standard Kajaani fiber analysis test procedure. The weighted average fiber length may be an arithmetic average, a length weighted average or a weight weighted average and may be expressed by the following equation:

[0043] k

[0044] (xi*ni) / n

[0045]

[0046] xi=0

[0047] where

[0048] k=maximum fiber length

[0049] xi=fiber length

[0050] ni=number of fibers having length xi

[0051] n=total number of fibers measured.

[0052] One characteristic of the average fiber length data measured by the Kajaani fiber analyzer is that it does not discriminate between different types of fibers. Thus, the average length represents an average based on lengths of all different types, if any, of fibers in the sample.

[0053] As used herein the term "staple fibers" means discontinuous fibers made from synthetic polymers or regenerated cellulose, such as polypropylene, polyester, post consumer recycle (PCR) fibers, polyester, nylon, viscose, rayon, and the like, and those not hydrophilic may be treated to be hydrophilic. Staple fibers may be cut fibers or the like. Staple fibers can have cross-sections that are round, bicomponent, multicomponent, shaped, hollow, or the like.

[0054] The term “plied” or “bonded” or “coupled” refers herein to the joining, adhering, connecting, attaching, or the like, of two elements. Two elements will be considered plied, bonded or coupled together when they are joined, adhered, connected, attached, or the like, directly to one another or65127350PCT02 KCX-2167-PCT

[0055] indirectly to one another, such as when each is directly bonded to intermediate elements. The plying, bonding or coupling of one element to another can occur via continuous or intermittent bonds.

[0056] As used herein, “binder fibers” are fibers that can bond to other fibers in a substrate using chemical, mechanical, or thermal means. The binder fibers may comprise thermally bondable fibers that, when heated, form thermal bonds with other fibers at their point of intersection. In one aspect, the binder fibers include a surface polymer having a lower melting temperature. For instance, the binder fibers can be made from a polymer, such as a polyolefin, having a melting temperature of less than 200°C, such as less than 180°C, such as less than 160°C, such as less than 140°C, such as less than 120°C, such as less than 100°C, and greater than 80°C, such as greater than 90°C. In one aspect, the binder fibers comprise conjugate fibers, such as bicomponent fibers. The conjugate fibers can have a core and sheath structure, including a core polymer surrounded by a sheath polymer. The core polymer can have a higher melting temperature than the sheath polymer. The core polymer can be selected for its strength and high melting point and the sheath polymer can be made from a polymer selected for its lower melting temperature. The core polymer, for instance, can have a melting temperature higher than the sheath polymer. In this manner, the sheath polymer, when subjected to heat, melts and bonds to other fibers within the web at intersecting points. The core polymer, however, allows the bicomponent binder fiber to retain its shape and provide strength.

[0057] As used herein, “synthetic polymer fibers” refers to fibers made from polymers that are not binder fibers. Synthetic polymer fibers can include polyester fibers, such as fibers made from a polyethylene terephthalate polymer. Other polymer synthetic fibers include polyolefin fibers, such as polyethylene fibers, polypropylene fibers, and fibers made from copolymers of the above.

[0058] As used herein, “resilient fibers” refers to fibrous materials that bend and deform under an applied load but largely recover their shape to their original dimensions after removal of the applied load. These fibers when combined with other fibers and materials and are incorporated in an absorbent composite, enable the composite material to largely recover its shape when a load is applied and them removed.

[0059] Examples of resilient fibres include both natural and synthetic fibers Examples of natural cellulosic fibers would include crosslinked celuulosic fibers, regenerated cellulosic fibers, and natural cellulosic fibers such as coconut coir fibers. Examples of resilient synthetic fibers include staple fibers of various types. The staple fibers could be made from many different polymers including polyolefins, polyesters, nylons, and acrylics. The synthetic staple fibers could be hydrophilic or hydrophobic and could be treated suitably to derive the desired level of wettability. The staple fibers can have crosssections that are circular, bicomponent such as side-by-side, concentric, or eccentric, shaped with different cross sections, hollow, or other types.65127350PCT02 KCX-2167-PCT

[0060] The binder fibers can be used together with other fibers and enable the structure to be bonded using themal bonding, mechanical bonding, or chemical bonding. The eccentric bicomponent fibers can also change their shape and contribute to the resilience of the structure by creating shapes that are more resistant to deformation under load. Crimping and curling of the fibers can also be used to impart a shape and geometry to the fiber that would be more resistant to deformation under an applied load and thereby create a more resilient fiber.

[0061] As used herein, “FIUP Test” is as follows and as described in WO 2023 / 164126, which is incorporated herein by reference. During the FIUP Test, first, second, and third intake times of experimental codes are measured according to the following protocol and by the exemplary equipment illustrated in FIG. 5 for a Fluid Intake Under Pressure (FIUP) Test of PCT Publication WO 2023 / 164126. The specimens are prepared to the following dimensions: 215 mm in length and 62 mm in width and placed between the topsheet with flaps and the back sheet from the commercially available Poise® Ultra Thin Moderate 4-drop Regular pads. The topsheet can be a 20gsm polypropylene spunbond nonwoven liner material with hydrophilic treatment, such as XHBY21520 / YSQS215 material provided by Lanxi Xinghan Plastic Material Co. (Hengyao). The back sheet can be a 24gsm polyethylene film. For specimens without an intake layer, a fresh piece of 185mm by 49mm intake layer material of 42gsm polyethylene / polypropylene bicomponent TABCW (JingLan) is placed over the core to serve as an intake layer and 6gsm of adhesive is applied (from a swirl of adhesive on release paper) to the top and bottom of the intake layer. The sides of the sample are sealed with double-sided tape. The samples are brought to TAPPI conditions for at least 4 hours.

[0062] The FIUP Test uses a “bladder box” as illustrated in FIGS. 5 and 6 of PCT Publication WO 2023 / 164126. The bladder box includes a cover, a housing, an inflatable bladder, and a control unit. The cover can be made from a clear material, such as clear, cast acrylic. The cover can be hinged to the housing. The housing can be constructed from aluminum and can be of the size of 62cm x 40cm x 15cm. The housing can also include latches, such as the three latches depicted in FIGS. 5 and 6, for securing the cover to the housing. When the cover is opened, the test specimen can be laid on top of a thin plastic film laid on top of the bladder. The test specimen should be laid on the film and bladder such that the specimen is centered under the intake port. The bladder can be an inflatable bladder, such as an Aero Tec Labs bladder, that can fit within the housing and that can be filled with compressed air.

[0063] The intake port can include a threaded funnel that threads into a threaded plug having a 1” diameter opening at the bottom of the threaded plug and provides for communication to the test specimen. The intake port can also include an O-ring that seals the threaded plug with the cover. The65127350PCT02 KCX-2167-PCT

[0064] intake port can also include a round, flat gasket (not shown) to seal between the threaded funnel and the threaded plug. The bottom of the intake port should be flush with the underside of the cover.

[0065] The control unit can be a process controller such as 1 / 16 DIN Fuzzy Logic; Example: Omega, part number CN48001-F1-AL2: G1, or equivalent, and can be configured to be in communication with a pressure transmitter measuring the pressure of the bladder. An exemplary pressure transmitter can be a Omega Engineering, part number PX181-015GSV. The control unit can also be in communication with a fluid dispensing pump (e.g., Cole-Parmer peristaltic pump, P / N 07551-20) and pump head (P / N 77201-60) that is set up to deliver fluid to the test sample at a specified flow rate of 8mL / s via clear pump tubing 214 (e.g., Masterflex clear tubing L / S 14, L / S 25, or L / S 17). The end fitting on the tubing can have an exit diameter of 0.125”, such as Cole-parmer Reducing Connector, Nylon, 1 / 4" x 3 / 16”, Item No. 30622-30.

[0066] After the test specimen is set in the bladder box housing, it is centered below the intake port. As illustrated in FIG. 5, the bottom of the cover can include two strips of hook tape (e.g., Item # 1055, Dariss Brand) that are used to help secure the test specimen. After the sample is centered, the cover is closed and the latches are latched. The hook tape should be applied to the cover such that the hook tape only touches non-absorbent material of the test specimen. The power for the control unit is turned on to set the bladder pressure to 0.25psi. Once the control unit identifies that the bladder has reached a stable pressure of 0.25psi, a pressure gauge can be checked to verify that the pressure in the bladder is within 0.25 + / - 0.01 psi. If the pressure is not within 0.01 psi of 0.25psi, the test should be stopped and the set pressure should be adjusted to compensate until the pressure gauge reads within 0.01 psi of 25psi.

[0067] The insult liquid used for the FIUP test is 0.9 ± 0.005% (w / w) aqueous isotonic saline that is placed in a heated water bath at a temperature of 98.6 ± 1.8 °F / 37 ± 1 °C prior to testing. The saline solution temperature should be confirmed with a thermometer prior to insulting the test specimen. The first insult is a 25mL or 8 mL insult and is supplied through the intake port by aiming the fluid at the bottom angled side of the funnel. The first intake time of the first insult begins once the pump is turned on to deliver fluid to the intake port and continues until all droplets of fluid have been absorbed within top layer of the test specimen. The second 25mL or 8 mL insult is applied 15 minutes after the first insult is fully absorbed and the second intake time is measured in the same manner as the first insult time. The third 25mL or 8 mL insult is applied 15 minutes after the second insult is fully absorbed and the third intake time is measured in the same manner as described above.

[0068] After the third intake time is recorded, a timer should be started to allow two minutes to pass. The control unit is then calibrated to stop the test by releasing the bladder pressure in the bladder box.65127350PCT02 KCX-2167-PCT

[0069] If at any point during the insult testing there is any fluid runoff beyond the test specimen on to the plastic sheet covering the bladder, the test should be marked as a “FAIL" and not recorded.

[0070] The testing is conducted with a sample set of N=5.

[0071] A “rewet'' test can be conducted after the third insult as described above using the same specimen. In other words, the rewet test is a continued test after the FIUP test is completed.

[0072] Specifically, 2 minutes after the third insult of the FIUP test is complete, the sample is removed from the bladder box and placed onto a flat surface, insult side facing up. The test is completed using two stacked pieces of blotting paper (e.g., 300 g / m2 (100 Ib. / ream) - Verigood Grade 88 by 300 ± 13 mm (3.5 by 12 ± 0.5 inch)) to absorb the free saline from the insulting point of the specimen under an external load after the FIUP test. The two pieces of blotting paper are pre-weighed and each had a dimension of 3.5” x 12” and are placed to cover the center of the specimen's insulting point by removing the FIUP testing board and adding a cylindrical weight of 249g and having a 1 inch diameter on the top of the blotting papers at the insult point to create a pressure of 0.7 psi for a period of two minutes. The mass of the wetted blotter papers is then measured and the rewet is calculated as: Rewet = total wet mass - dry mass. The higher the amount of wet weight measured from the test, the higher the rewet value the specimen had.

[0073] As used herein, thickness measurements utilize a standard bulk tester with clear, cast acrylic foot that provides 0.05psi.

[0074] As used herein, the Horizontal Side Compression Test is performed as follows with reference to Figures 7A and 7B of WO 2023 / 164126 which is incorporated herein by reference. During the test, the absorbent material is compressed horizontally. The test is designed to compress an absorbent product in the crotch area to measure the resiliency, flexibility or stiffness, and width recovery of the crotch area of the product.

[0075] The test protocol has 10 compression cycles of a dry product followed by 10 compression cycles of wet product. A relevant test fluid, saline or defibrinated swine blood, is applied to the product following the dry compression cycles. This test is performed with the product in a horizontal position to represent the typical user position of active wear. Additionally, a horizontal placement facilitates the ability to insult the products with the test fluids without needing to remove the test sample from the apparatus.

[0076] The product may be tested with or without flaps and / or with or without wings. Test outputs include energy, resiliency, and width recovery.

[0077] A CRE (Constant Rate of Extension) type of tensile tester with data acquisition unit and data acquisition program capable of collecting data such as Instron 3343 system with Bluehill program or65127350PCT02 KCX-2167-PCT

[0078] MTS Insight 1EL system with TestWorks 4.0 is used during the test. The product being tested is oriented horizontally in the test jaws.

[0079] Unless otherwise indicated, defibrinated swine blood @ 35% red blood cells is used which is available from Cocalico Biologicals, Inc.

[0080] The product should be conditioned for 4 hours in TAPPI conditions prior to testing. The center point and insult location of each product should be marked. For incontinence and menstrual pads, measure the length of the entire product and divide by 2. This value will represent the center point. Put a vertical mark at the center point. The center point will be the insult location.

[0081] The Test is conducted by warming up the tensile tester according to the manufacturer's manual. Next, verify the appropriate load cell is in the tensile tester, which should be selected from either a 50 Newton or 100 Newton maximum, depending on the peak force value of the sample being tested, such that the majority of peak load values fall between 5-95% of the load cell's full scale value. For purposes of the samples tested herein, a 100 Newton load cell is used. In this test, both edges of the absorbent material are clamped between top and bottom grips of the tensile tester with the center of the sample aligned with the center of the grips and the sample centered between the grips. The computer is turned on and the software menu selection is followed. The load cell for the tensile tester is calibrated according to the manufacturer’s instructions. The test conditions are as follows.

[0082] Cross Head Speed 508 + / - 5mm / min

[0083] Gauge Length 90mm (initial compression plate separation distance)

[0084] End Compression Distance 30mm

[0085] Load Unit Newton

[0086] Full Scale Load 100 Newton (use an appropriate load cell for the product being tested so that the test value falls between 5% and 95% of the full-scale load)

[0087] Sample materials can be placed in product form by using the absorbent product sample. Ensure the lanyard thread is in and remains in the wheel guides, one in the front and two wheel guides in the back of the tester (see Figures 7A and 7B from WO 2023 / 164126). A piece of masking tape can be placed close to one of the back wheels of the tester without touching the lanyard to prevent the lanyard moving out of the wheel when the crosshead returns to its start position. Two hanging weights are attached to the wheel guide at the far back of the testing unit. Orient the weights up-side down to shorten the hook length such that the weights do not touch the frame.65127350PCT02 KCX-2167-PCT

[0088] With the lanyard attached to a hook below the load cell, adjust the crosshead so the resultant force exerted by the lanyard is less than 0.5 grams. Measure and then record the initial width of the specimen in the mid-crotch area. Then, zero the crosshead channel and start the test run.

[0089] At the end of the 10thcycle in the dry condition, the test will pause with fixture open at the initial plate compression separation distance. Add a single insult of test fluid at the insult location (5 mL). Run 10 more cycles.

[0090] At the conclusion of all cycles, measure and record the final width of the specimen in the midcrotch area. A data report is generated that provides the cycle 1 energy, cycle 10 energy and cycle 20 energy (gf*cm). The width recovery % is measured as final width at end of all cycles divided by the initial width, multiplied by 100.

[0091] As used herein, the Heated (Gush) Intake Test is as follows. The Heated Intake Test evaluates product absorbent performance using an anatomical shaped surface. The test is conducted with menses simulant. The menses simulant is described in US Patent Application 2014 / 0121625, which is incorporated herein by reference. The product is held in a curved position close to the surface of the point of insult and uses body temperature above and below the pad, allowing a curved absorbent surface to accept the fluid insults through an oval shaped orifice. The test is done at body temperature using a trickle of 5 ml of menses simulant before a 2 ml timed gush at 24 ml / minute is introduced. The time taken to absorb the fluid gush insult is measured and recorded as intake time in seconds.

[0092] As used herein, the Retention Capacity Test is as follows. This test is used to determine the amount of defibri n ated swine blood testing fluid absorbed and retained by an absorbent product. The weight in grams of defibrinated blood absorbed by the product is recorded. Defibrinated Swine Blood with Gentamicin, 35% Hematocrit (% red blood cells) available from Cocalico Biologicals is used in the test. The products to be tested are weighed prior to testing and placed on mesh screens into saturation containers so the products are body-side up. The containers are placed on a rocker and an adequate amount of defibrinated swine blood is added so that it just covers the product. More swine blood may be added throughout the soaking time, if necessary, to ensure the pad is fully covered. The rocker is turned on so that it rocks very slowly and gently, and the fluid moves freely to both ends of the container. The product is allowed to saturate with the blood for 30 minutes followed by removal from the saturation container and excess fluid allowed to drip for five minutes. The product is then transferred to a vacuum box and placed on a screen with the body-side facing the screen and a vacuum of 0.5 psi is applied and the product held for 5 minutes. Excess free fluid is drained from the product and the product is then weighed. The difference in weight between the weight of the product after the test and the dry product before the test is recorded as retention capacity of the product.65127350PCT02 KCX-2167-PCT

[0093] As used herein, superabsorbent material spacing and packing density are measured as follows. The method for determining the spacing of SAM particles includes the first step of acquiring digital x-ray Micro-CT images of a sample. These images are acquired using a SkyScan 1272 CMOS Micro-CT system available from Bruker microCT (2550 Kontich, Belgium). An approximately 4 cm x 1 cm piece of the sample is cut and attached to a mounting apparatus, using double-sided tape, supplied by Bruker with the SkyScan 1272 system, so that it will not move under its own weight during the x-ray scanning process. The sample is mounted so it is positioned vertically in the sample chamber. The following SkyScan 1272 CMOS conditions are used during the scanning process:

[0094] Source Voltage (kV) = 30

[0095] Source Current (uA) = 150

[0096] Image Pixel Size (urn) =3.0

[0097] Image Format=TIFF

[0098] Rotation Step (deg.) = 0.1

[0099] Use 360 Rotation=NO

[0100] Frame Averaging=ON (6)

[0101] Random Movement=ON (10)

[0102] Flat Field Correction=ON

[0103] Filter=No Filter

[0104] After sample scanning is completed, the resulting X-ray projection image set is then reconstructed using the NRecon program provided with the SkyScan 1272 CMOS Micro-CT system. While reconstruction parameters can be somewhat sample dependent, and should be known to those skilled in the art, the following parameters should provide a basic guideline to an analyst:

[0105] Image File Type = JPG

[0106] Pixel Size (urn) = 3.0

[0107] Smoothing = 1 (Gaussian)

[0108] Ring Artifact Correction = 10

[0109] Beam Hardening Correction (%) = 10

[0110] After reconstruction is completed, the resulting image data set is now ready for SAM spacing measurements analysis using Leica Microsystems image analysis software.

[0111] The image analysis software platform used to perform the SAM spacing measurements can either be a QWIN Pro (Version 3.5.1) or LAS Macro Editor (Version 4.5.0) available from Leica Microsystems, having an office in Heerbrugg, Switzerland.

[0112] Thus, the method for determining SAM spacing measurements of a given sample includes the step of performing measurements on the ROI image slices from the Micro-CT image set.65127350PCT02 KCX-2167-PCT

[0113] Specifically, an image analysis algorithm is used to read and process images as well as perform measurements. The image analysis algorithm is reproduced below.

[0114] NAME = Spacing - 1

[0115] PURPOSE = Measures spacing between SAM particles

[0116] CONDITIONS = Bruker SkyScan 1272 Images

[0117] AUTHOR = D. G. Biggs

[0118] DATE = May 24, 2023

[0119] DEFINE VARIABLES & OPEN FILES

[0120] Open File (C:\Data\04704 - Lam\data.xls, channel #1) - Location to where data is saved. MFLDIMAGE = 3

[0121] TOTCOUNT = 0

[0122] TOTFIELDS = 0

[0123] IMAGE = 0

[0124] ACQOUTPUT = 0

[0125] MFRAMEH = 1820

[0126] MFRAMEW = 1237

[0127] SAMPLE ID AND SET UP

[0128] Enter Results Header

[0129] File Results Header (channel #1)

[0130] File Line (channel #1)

[0131] PauseText (“Enter image file prefix name.")

[0132] Input (TITLES)

[0133] Image frame (x 0, y 0, Width 1876, Height 1900)

[0134] Measure frame (x 223, y 18, Width 1432, Height 1860)

[0135] - Calvalue = 4.0 um / px

[0136] CALVALUE = 30

[0137] Calibrate (CALVALUE CALUNITSS per pixel)

[0138] FRMAREA = MFRAMEH*MFRAMEW*(CALVALUE**2)

[0139] Clear Accepts

[0140] For (SAMPLE = 1 to 1, step 1)

[0141] IMAGE ACQUISITION AND DETECTION65127350PCT02 KCX-2167-PCT

[0142] For (IMAGE = 1000 to 2000, step 50) - Analysis of image slices numbered 1000 to 2000 at every 50th

[0143] ACQFILE$ = " C:\lmages\04704 - Lam\Spacing lmages\Code

[0144] 23.11,268\"+TITLE$+""+STR$(IMAGE)+ ".bmp" - Computer location of image slices

[0145] Read image (from file ACQFILES into ACQOUTPUT)

[0146] Detect (whiter than 83, from ImageO into BinaryO)

[0147] IMAGE PROCESSING

[0148] Binary Amend (Open from BinaryO to Bin ary 1, cycles 2, operator Disc, edge erode on) Binary Amend (Close from Binary 1 to Binary2, cycles 2, operator Disc, edge erode on) Binary Identify (FillHoles from Binary2 to Binary3)

[0149] Binary Amend (Open from Binary3 to Binary4, cycles 2, operator Disc, edge erode on) MEASURE % AREA AND SPACING

[0150] Measure field (plane MFLDIMAGE, into FLDRESULTS (4), statistics into FLDSTATS (7,4)) Selected parameters: Area, Intercept H, Intercept V, Area%

[0151] Field Histogram #1 (Y Param Number, X Param Area%, from 0. to 60., linear, 20 bins) Display Field Histogram Results (#1, horizontal, differential, bins + graph (Y axis linear), statistics)

[0152] Data Window (1266, 227, 414, 371)

[0153] MEANSPACING = (FRMAREA-FLDRESULTS (1)) / (FLDRESULTS (2) +FLDRESULTS (3)) / 2

[0154] Field Histogram #2 (Y Param Number, X Param MEANSPACING, from 10. to 10000., logarithmic, 20 bins)

[0155] Next (IMAGE)

[0156] OUTPUT:

[0157] File (“%Area Histogram", channel #1)

[0158] File Line (channel #1)

[0159] File Field Histogram Results (#1, differential, statistics, bin details, channel #1)

[0160] File Line (channel #1)

[0161] File Line (channel #1)

[0162] File (“Mean SAM Particle Spacing", channel #1)

[0163] File Line (channel #1)

[0164] File Field Histogram Results (#2, differential, statistics, bin details, channel #1)

[0165] Next (SAMPLE)

[0166] Close File (channel #1)65127350PCT02 KCX-2167-PCT

[0167] END

[0168] The algorithm is executed using the Leica QWIN or LAS platform. Once the algorithm has analyzed the designated images, raw data results can be found in an EXCEL file located at the designated computer hard drive folder shown at the Open File line above. The resulting data displayed in the EXCEL file includes a histogram of spacing measurements with statistical information such as mean and standard deviation. A single measurement is made on each of image slices analyzed.

[0169] DETAILED DESCRIPTION

[0170] It is to be understood by one of ordinary skill in the art that the present discussion is a description of exemplary embodiments only and is not intended as limiting the broader aspects of the present disclosure.

[0171] The present disclosure is directed to methods and systems that can produce nonwoven substrates. While the present disclosure provides examples of substrates manufactured through foam-forming, it is contemplated that the methods and apparatuses described herein may be utilized to benefit wet-laid and / or air-laid manufacturing processes.

[0172] Each example is provided by way of explanation and is not meant as a limitation. For example, features illustrated or described as part of one embodiment or figure can be used on another embodiment or figure to yield yet another embodiment. It is intended that the present disclosure include such modifications and variations.

[0173] When introducing elements of the present disclosure or the preferred embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. As used herein, the terminology of “first,” “second,” “third”, etc. does not designate a specified order, but is used as a means to differentiate between different occurrences when referring to various features in the present disclosure. Many modifications and variations of the present disclosure can be made without departing from the spirit and scope thereof Therefore, the exemplary embodiments described herein should not be used to limit the scope of the invention.

[0174] In general, the present disclosure is directed to absorbent structures and / or absorbent articles demonstrating excellent fluid handling properties. In one aspect, for instance, absorbent articles made according to the present disclosure can be capable of not only rapidly absorbing fluids but retaining significant amounts of fluids while remaining relatively thin and flexible. In this manner, absorbent articles made according to the present disclosure can provide supreme comfort to the wearer.65127350PCT02 KCX-2167-PCT

[0175] The absorbent substrate of the present disclosure can be designed to not only be thin but also capable of absorbing different fluids or liquids with different properties. For instance, the absorbent substrate is particularly well suited for absorbing both relatively high viscosity liquids and relatively low viscosity liquids. For example, the absorbent substrate of the present disclosure comprises a unitary structure that displays excellent absorbent performance with respect to both urine and menses.

[0176] The absorbent substrate is not only well suited to absorbing different fluids but also has excellent strength and toughness properties that make the absorbent substrate well suitable for use in high-speed converting processes during the manufacture of absorbent articles and personal care products.

[0177] Overall, the absorbent substrate of the present disclosure not only provides excellent comfort and fit properties but also provides discretion benefits by absorbing both urine and menses in an efficient manner and in a single product.

[0178] The absorbent substrate of the present disclosure contains superabsorbent material combined with resilient fibers, such as crosslinked cellulose fibers. In accordance with the present disclosure, the superabsorbent material is spaced within the substrate in a manner that optimizes absorption of different fluids. In particular, the superabsorbent particles are spaced apart for rapidly absorbing high viscosity fluids, such as menses, while having sufficient density and amount to also rapidly absorb urine.

[0179] In one aspect, the absorbent articles contain a multi-layer absorbent substrate that has excellent physical properties while maximizing the use of a superabsorbent material. In one embodiment, the multi-layer absorbent substrate contained within the absorbent article comprises a foam formed nonwoven material that can be produced in rolls and then cut to a desired size. The multi-layer absorbent substrate can be made relatively thin and flexible while still having sufficient strength to be manipulated during formation of the articles.

[0180] For instance, the multi-layered absorbent substrate can include an intake or top layer, a retention or absorbent layer, and optionally a fluid distribution layer. The retention layer is positioned between the intake layer and the distribution layer. The intake layer contains coarse fibers, such as synthetic polymer fibers and / or binder fibers (e.g. bi-component fibers), in order to provide adequate void volume and resiliency for fast fluid absorption. The intake layer also provides web integrity.

[0181] The retention layer contains superabsorbent particles combined with resilient fibers. As described above, the superabsorbent particles are spaced apart within the retention layer for absorbing different types of fluids. For instance, the weight ratio of the resilient fibers to the superabsorbent material within the retention layer can be greater than about 0.2, such as greater than about 0.25, such as greater than about 0.27, such as greater than about 0.3.65127350PCT02 KCX-2167-PCT

[0182] The fluid distribution layer, on the other hand, can contain binder fibers in addition to cellulose fibers and / or polymer synthetic fibers. In one aspect, the fluid distribution layer can contain pulp fibers or cellulose fibers in amounts sufficient to provide a capillary pressure gradient to drive fluid down into the layer. The fluid distribution layer, for instance, can prevent against early fluid saturation of the retention layer thus allowing additional insults to be absorbed at fast rates. The fluid distribution layer also captures the superabsorbent material within the middle of the product and provides fluid distribution and web integrity.

[0183] Referring to FIG. 1, for exemplary purposes only, one embodiment of an absorbent article 200 made in accordance with the present disclosure is shown. Absorbent articles made in accordance with the present disclosure can comprise diapers, child training pants, other absorbent child pants, adult incontinence products, and the like. In one particular embodiment as shown in FIG. 1, the present disclosure is directed to an absorbent article that serves as a feminine hygiene product, such as a feminine care absorbent article 200.

[0184] More particularly, the article 200 includes a liner 226, a baffle 228, and an absorbent substrate 233 positioned between the liner 226 and the baffle 228. The liner 226 defines a body-facing surface of the absorbent article 200. The absorbent substrate 233 is positioned inwardly from the outer periphery of the absorbent article 200 and includes a body-facing side positioned adjacent the liner 226 and a garment-facing surface positioned adjacent the baffle 228. Typically, the liner 226 and the baffle 228 are joined by adhesive bonding, ultrasonic bonding, or any other suitable joining method known in the art, the sealed edges defining an overall sealed peripheral edge 299 of the article 200. The article 200 may take on various geometries but will generally have opposite lateral sides and longitudinal ends.

[0185] The liner 226 helps provide comfort and conformability, and also helps direct bodily exudates away from the body toward the absorbent substrate 233. Typically, the liner 226 and the baffle 228 have peripheral margins 299 that extend outwardly beyond the terminal, peripheral edges of the absorbent member 230, and the extending margins are joined together to partially or entirely, surround or enclose the absorbent core. The liner 226 contacts the body of the user and is liquid-permeable. The liner 226 may be formed from one or multiple layers of materials. The liquid-permeable liner 226 has an outwardly facing surface that may contact the body of the wearer and receive fluids from the body. The liner 226 may define an inner region positioned between laterally spaced first and second outer regions. The inner and outer regions may be formed from a single section of material, or from multiple sections. Whether having one or multiple sections, the liner 226 may be made from any liquid-permeable material known in the art. For example, the liner 226 can be constructed of any woven or nonwoven material that is easily penetrated by bodily exudates. Examples of suitable65127350PCT02 KCX-2167-PCT

[0186] materials include rayon, bonded carded webs of polyester, polypropylene, polyethylene, nylon, or other heat-bondable fibers, polyolefins, such as copolymers of polypropylene and polyethylene, linear low-density polyethylene, and aliphatic esters such as polylactic acid. Finely perforated film webs and net material can also be used. A specific example of a suitable topsheet material is a bonded carded web made of polypropylene and polyethylene, such as that used as topsheet stock for KOTEX® pantiliners. Such materials typically have a basis weight of less than about 100 gsm, and in some embodiments, from about 10 gsm to about 40 gsm.

[0187] The baffle 228 is generally liquid-impermeable and designed to face the inner surface, i.e., the crotch portion of an undergarment (not shown). The baffle 228 may permit a passage of air or vapor out of the absorbent article 200, while still blocking the passage of liquids. Any liquid-impermeable material may generally be utilized to form the baffle 228. For example, one suitable material that may be utilized is a microporous polymeric film, such as polyethylene or polypropylene. In particular embodiments, a polyethylene film is utilized that has a thickness in the range of about 0.2 mils to about 5.0 mils, and particularly between about 0.5 to about 3.0 mils. A specific example of a baffle material is a polyethylene film such as that used in KOTEX® pantiliners.

[0188] A nonwoven material 233 or an absorbent substrate made in accordance with the present disclosure is incorporated into the feminine care absorbent article 200. In particular, the absorbent substrate 233 is positioned between the liner 226 and the baffle 228 for absorbing and retaining body exudates, including menses and urine. As described above, in one embodiment, the nonwoven material 233 can comprise a multi-layer (or multi-zone) absorbent substrate.

[0189] The liner 226 may be maintained in secured relation with the absorbent structure 230 by bonding all or a portion of the adjacent surfaces to one another. A variety of bonding mechanisms known to one of skill in the art may be utilized to achieve any such secured relation. Examples of such mechanisms include, but are not limited to, the application of adhesives in a variety of patterns between the two adjoining surfaces, entangling at least portions of the adjacent surface of the absorbent with portions of the adjacent surface of the cover, or fusing at least portions of the adjacent surface of the cover to portions of the adjacent surface of the absorbent (e.g., ultrasonically fusing).

[0190] If desired, the feminine care absorbent article 200 may also include laterally extending wing portions 242 that may be integrally connected to side regions along the intermediate portion of the article. For example, the wing portions 242 may be separately provided members that are subsequently attached or otherwise operatively joined to the intermediate portion of the article. In other configurations, the wing portions may be unitarily formed with one or more components of the article. As representatively shown in FIG. 1, for example, either or both wing portions 242 may be formed from a corresponding, operative extension of the material employed to form the baffle 228.65127350PCT02 KCX-2167-PCT

[0191] Alternatively, either or both wing portions 242 may be formed from a corresponding, operative extension of the material employed to form the liner 226, or formed from a corresponding, operative combination of the topsheet and baffle materials.

[0192] If desired, the absorbent article 200 can further include an embossing pattern. The embossing pattern can be embossed into the liner and can extend at least partially into the middle of the absorbent substrate.

[0193] In one aspect, the absorbent substrate 233 comprises a multi-layer substrate that can be formed through a foam forming process. The absorbent substrate 233, for instance, can be a nonwoven material that is foam formed, wound into a roll, combined with the liner 226 and optionally the baffle 228 and then cut to a desired shape.

[0194] The absorbent substrate contains at least two layers, and, in one embodiment, contains three layers. The absorbent substrate or nonwoven material, for instance, can include an intake layer that is designed to be placed adjacent to the wearer, a retention layer for absorbing and retaining bodily fluids, and, optionally, a distribution layer. The distribution layer can form a bottom exterior layer and may be designed to prevent superabsorbent material from escaping the nonwoven material from the retention layer.

[0195] Referring to FIG. 2, for exemplary purposes, one example of a nonwoven material 10 made in accordance with the present disclosure is shown. FIG. 2 illustrates a three-layer embodiment. In particular, the nonwoven material 10 includes an intake layer 12 positioned adjacent to a retention layer 13. An interface 15 is located between the intake layer 12 and the retention layer 13. The nonwoven material 10 further includes a distribution layer 17. As shown, the retention layer 13 is positioned between the intake layer 12 and the distribution layer 17. An interface 19 is located between the retention layer 13 and the distribution layer 17. In one aspect, some of the materials or fibers contained in the intake layer 12 can mix with some of the materials or fibers contained in the retention layer 13 along the interface 15. Similarly, some of the fibers or materials contained in the retention layer 13 can mix with some of the fibers or materials contained in the distribution layer 17 at the interface 19. The interfaces 15 and 19 can provide the benefit of having some fiber distribution between adjacent zones or layers for providing enhanced stabilization properties.

[0196] The intake layer 12 and the distribution layer 17 can serve as containment layers for the retention layer 13. In particular, the intake layer 12 and the distribution layer 17 can be configured to be relatively thin and have a low basis weight while providing enough strength for handling and converting and while adding minimal stiffness. The retention layer 13 can contain a superabsorbent material that is prevented from contacting a user or wearer due to the presence of the intake layer 12 and the distribution layer 17. In this manner, the intake layer 12 and the distribution layer 17 can65127350PCT02 KCX-2167-PCT

[0197] improve the feel and comfort of the nonwoven material 10 by reducing any gritty feel that may occur when there is contact with superabsorbent materials. The intake layer 12 and the distribution layer 17 can also prevent superabsorbent materials from escaping making the nonwoven material easier to handle and process.

[0198] The intake layer 12 can be a top layer that is configured to face a wearer when the nonwoven material 10 is incorporated into an absorbent article. In one aspect, the intake layer 12 can be designed to quickly allow fluids including menses and urine to be absorbed by the retention layer 13.

[0199] For example, in one embodiment, the intake layer 12 can be a low density layer with high permeability characteristics.

[0200] In one aspect, the intake layer 12 can contain a mixture of binder fibers, synthetic polymer fibers, and optionally crosslinked pulp fibers.

[0201] Binder fibers that can be incorporated into the intake layer 12 include mono-component fibers and multi-component fibers. The multi-component fibers, for instance, can include a core polymer surrounded by a sheath polymer. The sheath polymer can be comprised of a low melting thermoplastic polymer such as polyethylene. In one aspect, the binder fibers comprise bicomponent fibers containing a core polymer made from a polyester polymer or a polypropylene polymer. For example, the core polymer can be a polyethylene terephthalate polymer. The sheath polymer, on the other hand, can have a lower melting temperature than the core polymer and can comprise a polyolefin, such as polyethylene.

[0202] The binder fibers can have any suitable size and length. For instance, the binder fibers can have a length of between about 0.5 mm to about 50 mm, such as from about 0.75 mm to about 30 mm. In one aspect, the binder fibers have a length of from about 1 mm to about 25 mm. The binder fibers, for instance, can have an average length of greater than about 2 mm, such as greater than about 3 mm, such as greater than about 4 mm, such as greater than about 5 mm, and less than about 12 mm, such as less than about 8 mm. The binder fibers can have a size of from about 0.5 dtex to about 20 dtex. In one aspect, for instance, the fibers can have a size of from about 0.8 dtex to about 3.5 dtex. In an alternative aspect, the binder fibers can have a size of from about 3.5 dtex to about 8 dtex.

[0203] In one embodiment, the intake layer 12 can contain a mixture of different binder fibers, such as first binder fibers and second binder fibers. The first binder fibers can comprise bi-component fibers having a size of from about 3.5 dtex to about 15 dtex and the second binder fibers can comprise bi-component fibers having a size of from about 0.8 dtex to about 3.5 dtex. All of the binder fibers can have an average length of from about 2 mm to about 8 mm, such as from about 4 mm to about 7 mm.65127350PCT02 KCX-2167-PCT

[0204] In one aspect, the intake layer 12 can contain binder fibers in an amount from about 30% by weight to about 75% by weight, including all increments of 1% therebetween. For example, the intake layer 12 can contain binder fibers in an amount greater than about 35% by weight, such as in an amount greater than about 40% by weight, such as in an amount greater than about 45% by weight, such as in an amount greater than about 50% by weight, such as in an amount greater than about 55% by weight. The binder fibers can generally be present in an amount less than about 75% by weight, such as less than about 70% by weight, such as in an amount less than about 65% by weight, such as in an amount less than about 60% by weight.

[0205] In addition to containing binder fibers, the intake layer 12 can contain various other materials, including other fibers. In one aspect, for instance, the intake layer 12 can contain synthetic polymer fibers. The synthetic polymer fibers, for instance, can be made from a polymer material and can be non-absorbent. As described above, in one aspect, the nonwoven material 10 can be produced using a foam forming process in which the fibers and other materials are suspended in a foam and then deposited onto a forming surface to form the multi-layer structure. Of advantage, the foam forming process can accommodate all different types of materials and fibers including polymer synthetic fibers. For example, the polymer synthetic fibers can have a bending stiffness that is substantially unimpacted by the presence of the forming fluid.

[0206] Examples of synthetic polymer fibers include polyolefin, polyester (PET), polyamide, polylactic acid, or other fiber forming polymers. Polyolefin fibers, such as polyethylene (PE) and polypropylene (PP), and polyethylene terephthalate fibers are particularly well suited for use in the present disclosure. In some embodiments, non-absorbent fibers can be recycled fibers, compostable fibers, and / or marine degradable fibers. In this regard, due to its very low levels of absorbency to water, water resistant fibers do not experience a significant change in bending stiffness upon contacting an aqueous fluid and therefore are capable of maintaining an open composite structure upon wetting. The fiber diameter of a fiber can contribute to enhanced bending stiffness. For example, a PET fiber has a higher bending stiffness than a polyolefin fiber whether in dry or wet states. The higher the fiber denier, the higher the bending stiffness a fiber exhibits. Water resistant fibers desirably have a water retention value (WRV) less than about 1 and still more desirably between about 0 and about 0.5. In certain aspects, it is desirable that the fibers, or at least a portion thereof, include non-absorbent fibers.

[0207] The synthetic and / or water resistant fibers can have fiber length greater than about 0.2 mm including, for example, having an average fiber size between about 0.5 mm and about 50 mm or between about 0.75 and about 30 mm or even between about 1 mm and about 25 mm. The average fiber size of the synthetic fibers, for instance, can be greater than about 2 mm, such as greater than65127350PCT02 KCX-2167-PCT

[0208] about 4 mm, and less than about 18 mm, such as less than about 12 mm, such as less than about 10 mm, such as less than about 8 mm.

[0209] In some embodiments, the synthetic and / or water resistant fibers can have a crimped structure to enhance bulk generation capability of the foam formed fibrous substrate. For example, a PET crimped staple fiber may be able to generate a higher caliper (or result in a low sheet density) in comparison to a PET straight staple fiber with the same fiber diameter and fiber length.

[0210] The size of the synthetic polymer fibers can be from about 0.5 dtex to about 25 dtex. For instance, the size of the synthetic polymer fibers can be greater than about 5 dtex, such as greater than about 8 dtex, such as greater than about 10 dtex, and less than about 20 dtex, such as less than about 15 dtex.

[0211] For exemplary purposes, the intake layer 12 can contain synthetic polymer fibers generally in an amount from about 10% by weight to about 60% by weight, including all increments of 1% by weight therebetween. For instance, the polymer synthetic fibers can be present in the intake layer 12 in an amount greater than about 25% by weight, such as in an amount greater than about 30% by weight, such as in an amount greater than about 35% by weight. The polymer synthetic fibers can be present in the intake layer 12 in an amount less than about 60% by weight, such as in an amount less than about 55% by weight, such as in an amount less than about 50% by weight. In one embodiment, the intake layer 12 only contains binder fibers combined and blended with synthetic polymer fibers.

[0212] In addition to or instead of polymer synthetic fibers, the intake layer 12 can also optionally contain cellulose fibers. Various different types of cellulose fibers can be incorporated into the intake layer 12. In one aspect, for instance, the intake layer 12 contains crosslinked pulp fibers in amounts less than 20% by weight, such as less than about 10% by weight.

[0213] In one aspect, the intake layer 12 can have a basis weight that is less than about 65 gsm, such as less than about 60 gsm, such as less than about 55 gsm, such as less than about 50 gsm, and greater than about 30 gsm, such as greater than about 35 gsm, such as greater than about 40 gsm, such as greater than about 45 gsm, such as greater than about 50 gsm.

[0214] The retention layer 13 contained in the nonwoven material 10 is generally configured to absorb fluids, particularly liquids, and includes absorbent material. The absorbent material can include absorbent particles including fibers and / or other absorbent components. The retention layer 13 can contain a superabsorbent material in combination with a plurality of fibers. For example, in one embodiment, the retention layer 13 includes superabsorbent material combined with resilient fibers and optionally binder fibers.

[0215] Various different superabsorbent materials (SAM) can be incorporated into the retention layer 13. SAM is commonly provided in a particulate form and, in certain aspects, can comprise polymers of65127350PCT02 KCX-2167-PCT

[0216] unsaturated carboxylic acids or derivatives thereof. In some forms, however, SAM can be configured in fiber form. These polymers are often rendered water insoluble, but water swellable, by crosslinking the polymer with a di- or polyfunctional internal crosslinking agent. These internally cross-linked polymers are at least partially neutralized and commonly contain pendant anionic carboxyl groups on the polymer backbone that enable the polymer to absorb aqueous fluids, such as body fluids.

[0217] Typically, the SAM particles are subjected to a post-treatment to crosslink the pendant anionic carboxyl groups on the surface of the particle. SAMs are manufactured by known polymerization techniques, desirably by polymerization in aqueous solution by gel polymerization. The products of this polymerization process are aqueous polymer gels, i.e., SAM hydrogels that are reduced in size to small particles by mechanical forces, then dried using drying procedures and apparatus known in the art. The drying process is followed by pulverization of the resulting SAM particles to the desired particle size. Examples of superabsorbent materials include, but are not limited to, those described in US7396584 Azad et al., US7935860 Dodge et al., US2005 / 5245393 to Azad et al., US2014 / 09606 to Bergam et al., W02008 / 027488 to Chang et al. and so forth.

[0218] In some embodiments involving SAM, the SAM may be treated by a water-soluble protective coating having a rate of dissolution selected such that the component is not substantially exposed to the aqueous liquid carrier until the highly-expanded foam has been formed and drying operations initiated that can remove the coating. Alternatively, in order to prevent or limit premature expansion during processing, the SAM may be introduced into the process at low temperatures.

[0219] The retention layer 13 can also contain resilient fibers. The resilient fibers are blended with the superabsorbent material and provide Z-directional loft to the layer which permits the spacing of the superabsorbent material within the layer. For example, in accordance with the present disclosure, the superabsorbent material is combined with the resilient fibers in a manner that spaces the superabsorbent particles apart a desired amount and provides a layer with an optimum superabsorbent particle density that was found to rapidly absorb not only urine but also more viscous fluids, such as menses.

[0220] The resilient fibers, for instance, can comprise particular types of cellulose fibers or can comprise synthetic fibers. Resilient cellulose fibers include crosslinked pulp fibers, bleached chemithermomechanical pulp fibers, regenerated cellulose fibers, and mixtures thereof. Synthetic resilient fibers can include synthetic polymer fibers such as polyester fibers, polylactic acid fibers, polyhydroxyalkanoate fibers, polypropylene fibers, and mixtures thereof. In one aspect, the retention layer 13 can contain resilient fibers comprising a mixture of resilient cellulose fibers and resilient synthetic fibers.65127350PCT02 KCX-2167-PCT

[0221] In accordance with the present disclosure, the weight ratio between the resilient fibers and the superabsorbent material is from about 0.25 to about 0.59. For instance, the weight ratio between the resilient fibers and the superabsorbent material can be greater than about 0.27, such as greater than about 0.3, such as greater than about 0.32, and less than about 0.55, such as less than about 0.51. The above ratios have been found to provide for adequate spacing of the superabsorbent particles.

[0222] The superabsorbent particles within the retention layer 13, for instance, can display a spacing of from about 480 microns to about 1,300 microns. The superabsorbent material spacing, for instance, can be greater than about 500 microns, such as greater than about 525 microns, such as greater than about 550 microns, such as greater than about 600 microns, such as greater than about 650 microns, such as greater than about 700 microns, such as greater than about 750 microns, such as greater than about 800 microns, and less than about 1,300 microns, such as less than about 1,200 microns, such as less than about 1,100 microns, such as less than about 1,000 microns. The packing density, on the other hand, can be from about 0.02 to about 0.055. The packing density, for instance, can be greater than about 0.03 and less than about 0.05, such as less than about 0.045.

[0223] In addition to the superabsorbent material and the resilient fibers, the retention layer 13 can optionally contain binder fibers. The binder fibers can be the same fibers as described above with respect to the intake layer 12. For instance, the retention layer 13 can contain a single type of binder fiber or can contain a mixture of binder fibers having different sizes.

[0224] The fiber basis weight (excluding the superabsorbent material) of the retention layer 13 can generally be from about 50 gsm to about 200 gsm. For instance, the fiber basis weight can be greater than about 60 gsm, such as greater than about 70 gsm, such as greater than about 85 gsm, such as greater than about 90 gsm, such as greater than about 95 gsm, such as greater than about 100 gsm, and less than about 150 gsm, such as less than about 130 gsm, such as less than about 125 gsm, such as less than about 120 gsm.

[0225] In one embodiment, all of the fibers contained in the retention layer 13 can comprise resilient fibers. Alternatively, the retention layer 13 can contain binder fibers in an amount less than about 30% by weight, such as in an amount less than about 20% by weight, such as in an amount less than about 15% by weight, such as in an amount greater than about 5% by weight, such as in an amount greater than about 10% by weight based upon the total weight of fibers present in the layer. The resilient fibers can be present in the retention layer 13 in an amount generally from about 50% by weight to about 100% by weight, such as in an amount greater than about 60% by weight, such as in an amount greater than about 70% by weight, such as in an amount greater than about 80% by weight.

[0226] The basis weight of the superabsorbent material contained in the retention layer 13 can be from about 100 gsm to about 700 gsm. In one aspect, the basis weight of the superabsorbent material65127350PCT02 KCX-2167-PCT

[0227] contained in the retention layer 13 is greater than about 175 gsm, such as greater than about 190 gsm, such as greater than about 200 gsm, and less than about 600 gsm, such as less than about 500 gsm, such as less than about 400 gsm.

[0228] As shown in FIG. 2, the nonwoven material 10 further includes a distribution layer 17. The distribution layer 17 can be made from different fiber furnishes. For instance, the distribution layer can contain binder fibers alone, binder fibers in combination with cellulose fibers, binder fibers in combination with synthetic fibers, or binder fibers in combination with cellulose fibers and polymer synthetic fibers.

[0229] In one aspect, the distribution layer 17 contains binder fibers, such as any of the binder fibers described above with respect to the intake layer 12. For example, the distribution layer 17 can contain bi-component binder fibers having a size of from about 0.8 dtex to about 5 dtex, such as from about 0.8 dtex to about 1.6 dtex. The binder fibers can be present in the distribution layer 17 generally in an amount from about 10% by weight to about 55% by weight. For instance, the binder fibers can be present in the distribution layer 17 in an amount greater than about 15% by weight, such as in an amount greater than about 20% by weight, such as in an amount greater than about 25% by weight, such as in an amount greater than about 30% by weight, such as in an amount greater than about 35% by weight, and in an amount less than about 50% by weight, such as in an amount less than about 45% by weight.

[0230] In one aspect, the distribution layer 17 only contains binder fibers in combination with cellulose fibers.

[0231] The cellulose fibers can generally be present in the distribution layer 17 in an amount from about 20% by weight to about 90% by weight. For instance, the cellulose fibers can be present in an amount greater than about 30% by weight, such as in an amount greater than about 40% by weight, such as in an amount greater than about 50% by weight, and in an amount less than about 80% by weight, such as in an amount less than about 70% by weight. The cellulose fibers can comprise pulp fibers, such as softwood fibers, hardwood fibers, or the like. The cellulose fibers can also comprise cellulose resilient fibers, such as crosslinked cellulose fibers. In one embodiment, the cellulose fibers comprise a mixture of softwood fibers and crosslinked pulp fibers in a ratio of from about 1:1 to about 4:1, such as in a ratio of from about 1.5:1 to about 2.5:1.

[0232] The distribution layer 17 as shown in FIG. 2 can generally have a basis weight of less than about 70 gsm, such as less than about 65 gsm, such as less than about 60 gsm, such as less than about 55 gsm, such as less than about 50 gsm. The basis weight of the distribution layer 17 can be greater than about 15 gsm, such as greater than about 20 gsm, such as greater than about 25 gsm.65127350PCT02 KCX-2167-PCT

[0233] In addition to the materials described above to form the different layers in the nonwoven material or multi-layer substrate, the multi-layer substrate can also contain various other additives and components. For example, wet strength additives can be added during formation of the substrate in order to help improve the relative strength of the multi-layer substrate.

[0234] Such strength additives suitable for use with paper making fibers and the manufacture of paper tissue are known in the art. Temporary wet strength additives may be cationic, nonionic or anionic. Examples of such temporary wet strength additives include PAREZ™ 631 NC and PAREZ(R) 725 temporary wet strength resins that are cationic glyoxylated polyacrylamides available from Cytec Industries, located at West Paterson, N. J. These and similar resins are described in US3556932 to Coscia et al. and US3556933 to Williams et al. Additional examples of temporary wet strength additives include dialdehyde starches and other aldehyde containing polymers such as those described in US6224714 to Schroeder et al.; US6274667 to Shannon et al.; US6287418 to Schroeder et al.; and US6365667to Shannon et al., and so forth.

[0235] Permanent wet strength agents comprising cationic oligomeric or polymeric resins may also be used in the present disclosure. Polyamide-polyamine-epichlorohydrin type resins such as KYMENE 557H sold by Solenis are the most widely used permanent wet-strength agents and are suitable for use in the present disclosure. Such materials have been described in the following US3700623 to Keim; US3772076 to Keim; US3855158 to Petrovich et al.; US3899388to Petrovich et al.; US4129528 to Petrovich et al.; US4147586 to Petrovich et al.; US4222921 to van Eenam and so forth. Other cationic resins include polyethylenimine resins and aminoplast resins obtained by reaction of formaldehyde with melamine or urea. Permanent and temporary wet strength resins may be used together in the manufacture of composite cellulosic products of the present disclosure. Further, dry strength resins may also optionally be applied to the composite cellulosic webs of the present disclosure. Such materials may include, but are not limited to, modified starches and other polysaccharides such as cationic, amphoteric, and anionic starches and guar and locust bean gums, modified polyacrylamides, carboxymethylcellulose, sugars, polyvinyl alcohol, chitosan, and the like.

[0236] When a wet strength additive is used, it is preferable to select an additive that is compatible with the foam agent used for the foam process. For example, when a strength additive is a cationic resin, due to incompatibility between a cationic and an anionic substance, a cationic surfactant is preferably used as a foam agent, or vice versa. A non-ionic surfactant is usually compatible with any cationic and anionic strength additives.

[0237] One or more wet strength additives can be incorporated into only one of the layers of the nonwoven material 10. For instance, a wet strength additive can be incorporated into the intake layer,65127350PCT02 KCX-2167-PCT

[0238] can be incorporated into the retention layer, and / or can be incorporated into the distribution layer. In one embodiment, at least one wet strength additive is incorporated into all three layers.

[0239] If used, such wet strength additives can comprise between about 0.01 and about 5% of the dry weight of cellulose fibers contained in the multi-layer substrate. In certain embodiments, the strength additives can comprise between about 0.05% and about 2% of the dry weight of cellulose fibers or even between about 0.1% and about 1% of the dry weight of cellulose fibers.

[0240] In one aspect, the absorbent substrate can contain a surfactant. The surfactant can comprise a non-ionic surfactant, an anionic surfactant, and possibly a cationic surfactant. In one aspect, the surfactant can be applied to the intake layer 12 in an amount of greater than about 0.1 gsm, such as in an amount greater than about 0.2 gsm, and in an amount less than about 0.6 gsm, such as in an amount less than about 0.4 gsm.

[0241] Still other additional components may be added to multi-layer substrate materials. For materials that are formed utilizing foam forming processes, other additional components should be reviewed as to ensure they do not significantly interfere with the formation of the foam, the hydrogen bonding as between the cellulosic fibers or other desired properties of the material. As examples, additional additives may include one or more pigments, opacifying agents, anti-microbial agents, pH modifiers, skin benefit agents, odor absorbing agents, fragrances, thermally expandable microspheres, surfactants or hydrophilic agents, foam particles (such as, pulverized foam particles), and so forth as desired to impart or improve one or more physical or aesthetic attributes. In certain embodiments, the multi-layer substrate may include skin benefit agents such as, for example, antioxidants, astringents, conditioners, emollients, deodorants, external analgesics, film formers, humectants, hydrotropes, pH modifiers, surface modifiers, skin protectants, and so forth.

[0242] Nonwoven materials, as described herein can be preferably formed through a foam forming process. FIG. 3 provides a schematic of an exemplary apparatus 11 that can be used as part of a foam forming process to manufacture a nonwoven material 10 that is a foam formed product. The apparatus 11 of FIG. 3 can include a first tank 14 configured for holding a first fluid supply 16. In some embodiments, the first fluid supply 16 can be a foam The first fluid supply 16 can include a fluid provided by a supply of fluid 18. In some embodiments, the first fluid supply 16 can include a plurality fibers provided by a supply of fibers 20, and preferably includes at least some absorbent fibers.

[0243] However, in other embodiments, the first fluid supply 16 can be free from a plurality of fibers altogether. The first fluid supply 16 can also include a surfactant provided by a supply of surfactant 22.

[0244] In some embodiments, the first tank 14 can include a mixer 24, as will be discussed in more detail below. The mixer 24 can mix (e.g., agitate) the first fluid supply 16 to mix the fluid, fibers (if present), and surfactant with air, or some other gas, to create a foam. The mixer 24 can also mix the foam with65127350PCT02 KCX-2167-PCT

[0245] fibers (if present) to create a foam suspension of fibers in which the foam holds and separates the fibers to facilitate a distribution of the fibers within the foam (e.g., as an artifact of the mixing process in the first tank 14). Uniform fiber distribution can promote desirable absorbent material 10 including, for example, strength and the visual appearance of quality.

[0246] The apparatus 11 can also include a second tank 26 configured for holding a second fluid supply 28. In some embodiments, the second fluid supply 28 can be a foam. The second fluid supply 28 can include a fluid provided by a supply of fluid 30 and a surfactant provided by a supply of surfactant 32. In some preferred embodiments, such as depicted in FIG. 3, the second fluid supply 28 is free from fibers. In other embodiments, the second fluid supply 28 can include a plurality of fibers in addition to or as an alternative to the fibers being present in the first fluid supply 16. In some embodiments, the second tank 26 can include a mixer 34. The mixer 34 can mix the second fluid supply 28 to mix the fluid and surfactant with air, or some other gas, to create a foam.

[0247] In some embodiments, the apparatus 11 can also include a third tank 31 configured for holding a third fluid supply 33. In some embodiments, the third fluid supply 33 can be a foam. The third fluid supply 33 can include a fluid provided by a supply of fluid 35 and a plurality of fibers provided by a supply of fibers 37, and preferably includes at least some synthetic fibers. The third fluid supply 33 can also include a surfactant provided by a supply of surfactant 39. In some embodiments, the third tank 31 can include a mixer 41. The mixer 41 can mix the third fluid supply 33 to mix the fluid and surfactant with air, or some other gas, to create a foam.

[0248] In some embodiments, the apparatus 11 can also include a fourth tank 66 configured for holding a fourth fluid supply 68. In some embodiments, the fourth fluid supply 68 can be a foam. The fourth fluid supply 68 can include a fluid provided by a supply of fluid 69 and a plurality of fibers provided by a supply of fibers 70. The fourth fluid supply 68 can also include a surfactant provided by a supply of surfactant 71. In some embodiments, the fourth tank 66 can include a mixer 72. The mixer 72 can mix the fourth fluid supply 68 to mix the fluid and surfactant with air, or some other gas, to create a foam.

[0249] In tanks 14, 26, 31, 66 the first fluid supply 16, the second fluid supply 28, the third fluid supply 33, and the fourth fluid supply 68, respectively, can be acted upon to form a foam. In some embodiments, the foaming fluid and other components are acted upon so as to form a porous foam having an air content greater than about 50% by volume and desirably an air content greater than about 60% by volume. In certain aspects, the highly-expanded foam is formed having an air content of between about 60% and about 95% and in further aspects between about 65% and about 85%. In certain embodiments, the foam may be acted upon to introduce air bubbles such that the ratio of expansion (volume of air to other components in the expanded stable foam) is greater than 1:1 and in65127350PCT02 KCX-2167-PCT

[0250] certain embodiments the ratio of air to other components can be between about 1.1:1 and about 20:1 or between about 1.2:1 and about 15:1 or between about 1.5:1 and about 10:1 or even between about 2:1 and about 5:1.

[0251] The foam can be generated by one or more means known in the art. Examples of suitable methods include, without limitation, aggressive mechanical agitation such as by mixers 24, 34, 41, 72 injection of compressed air, and so forth. Mixing the components through the use of a high-shear, high-speed mixer is particularly well suited for use in the formation of the desired highly-porous foams. Various high-shear mixers are known in the art and believed suitable for use with the present disclosure. High-shear mixers typically employ a tank holding the foam precursor and / or one or more pipes through which the foam precursor is directed. The high-shear mixers may use a series of screens and / or rotors to work the precursor and cause aggressive mixing of the components and air. In a particular embodiment, the first tank 14, the second tank 26, the third tank 31, and / or the fourth tank 66 is provided having therein one or more rotors or impellors and associated stators. The rotors or impellors are rotated at high speeds in order to cause flow and shear. Air may, for example, be introduced into the tank at various positions or simply drawn in by the action of the mixers 24, 34, 41, 72. While the specific mixer design may influence the speeds necessary to achieve the desired mixing and shear, in certain embodiments suitable rotor speeds may be greater than about 500 rpm and, for example, be between about 1000 rpm and about 6000 rpm or between about 2000 rpm and about 4000 rpm. In other embodiments, suitable rotor speeds may be less than 500 rpm.

[0252] In addition, it is noted the foaming process can be accomplished in a single foam generation step or in sequential foam generation steps for the first tank 14, the second tank 26, the third tank 31, and / or the fourth tank 66. For example, in one embodiment, all of the components of the first fluid supply 16 in the first tank 14 (e.g., the supply of the fluid 18, fibers 20, and surfactant 22) may be mixed together to form a slurry from which a foam is formed. Alternatively, one or more of the individual components may be added to the foaming fluid, an initial mixture formed (e.g. a dispersion or foam), after which the remaining components may be added to the initially foamed slurry and then all of the components acted upon to form the final foam. In this regard, the fluid 18 and surfactant 22 may be initially mixed and acted upon to form an initial foam prior to the addition of any solids. Fibers, if desired, may then be added to the water / surfactant foam and then further acted upon to form the final foam. As a further alternative, the fluid 18 and fibers 20, such as a high density cellulose pulp sheet, may be aggressively mixed at a higher consistency to form an initial dispersion after which the foaming surfactant 22, additional water and other components, such as synthetic fibers, are added to form a second mixture which is then mixed and acted upon to form the foam.65127350PCT02 KCX-2167-PCT

[0253] The foam density of the foam forming the first fluid supply 16 in the first tank 14, the foam forming the second fluid supply 28 in the second tank 26, the third fluid supply 33 in the third tank 31, and / or the fourth fluid supply 68 in the fourth tank 66 can vary depending upon the particular application and various factors, such as the fiber stock used. In some implementations, for example, the foam density of the foam can be greater than about 100 g / L, such as greater than about 250 g / L, such as greater than about 300 g / L. The foam density is generally less than about 800 g / L, such as less than about 500 g / L, such as less than about 400 g / L, such as less than about 350 g / L. In some implementations, for example, a lower density foam is used having a foam density of generally less than about 350 g / L, such as less than about 340 g / L, such as less than about 330 g / L.

[0254] The apparatus 11 can also include a first pump 36, a second pump 38, third pump 43, and fourth pump 73. The first pump 36 can be in fluid communication with the first fluid supply 16 and can be configured for pumping the first fluid supply 16 to transfer the first fluid supply 16. The second pump 38 can be in fluid communication with the second fluid supply 28 and can be configured for pumping the second fluid supply 28 to transfer the second fluid supply 28. The third pump 43 can be in fluid communication with the third fluid supply 33 and can be configured for pumping the third fluid supply 33 to transfer the third fluid supply 33. The fourth pump 73 can be in fluid communication with the fourth fluid supply 68 and can be configured for pumping the fourth fluid supply 68 to transfer the fourth fluid supply 68. In some embodiments, the first pump 36, the second pump 38, the third pump 43, and / or the fourth pump 73 can be a progressive cavity pump or a centrifugal pump, however, it is contemplated that other suitable types of pumps can be used.

[0255] As depicted in FIG. 3, the apparatus 11 can also include a component feed system 40. The component feed system 40 can be used to deliver a supply of component 44, if one is desired for the multi-layer substrate 10, by delivering the component 44 to one or more fluid supply 16, 28, 33, 68 or directly to the headbox 80. One exemplary component feed system 40 that can be used can include a component supply area 42 for receiving a supply of a component. The component feed system 40 can also include an outlet conduit 46. The component feed system 40 can also include a hopper 48. The hopper 48 can be coupled to the component supply area 42 and can be utilized for refiling the supply of the component 44 to the component supply area 42.

[0256] In some embodiments, the component feed system 40 can include a bulk solids pump. Some examples of bulk solids pumps that may be used herein can include systems that utilize screws / augers, belts, vibratory trays, rotating discs, or other known systems for handling and discharging the supply of the component 44. Other types of feeders can be used for the component feed system 40, such as, for example, an ingredient feeder, such as those manufactured by Christy65127350PCT02 KCX-2167-PCT

[0257] Machine & Conveyor, Fremont, Ohio. The component feed system 40 can also be configured as a conveyor system in some embodiments.

[0258] In some embodiments, the component feed system 40 can also include a pressure control system 50. In some embodiments, the pressure control system 50 can include a housing 52. The housing 52 can form a pressurized seal volume around the component feed system 40. In other embodiments, the pressure control system 50 can be formed as an integral part to the structure component feed system 40 itself, such that a separate housing 52 surrounding the component feed system 40 may not be required. The pressure control system 50 can also include a bleed orifice 54 in some embodiments.

[0259] The supply of the component 44 can be in the form of a particulate and / or a fiber and / or a powder. In one embodiment as described herein, the supply of the component 44 can be superabsorbent material (SAM) in particulate form. In some embodiments, SAM can be in the form of a fiber. Of course, other types of components, as previously discussed, are also contemplated as being utilized in the apparatus 11 and methods for forming an absorbent material 10 as described herein. The component feed system 40 as described herein can be particularly beneficial for a supply of component 44 that is most suitably maintained in a dry environment with minimal of exposure to fluid or foam utilized in the apparatus 11 and methods described herein.

[0260] The apparatus 11 can also include a first mixing junction 56 and a second mixing junction 58. In preferred embodiments, the first mixing junction 56 can be an eductor (also commonly referred to as a jet pump). The first mixing junction 56 can be in fluid communication with the outlet conduit 46 of the component feed system 40 and in fluid communication with the second fluid supply 28. The first mixing junction 56 can include a first inlet 60 and a second inlet 62. The first inlet 60 can be in fluid communication with the supply of the component 44 via the outlet conduit 46. The second inlet 62 can be in fluid communication with the second fluid supply 28. The first mixing junction 56 can also include a discharge 64. In preferred embodiments, the first mixing junction 56 can be configured as a co-axial eductor with the axis of the first inlet 60 being co-axial with the axis of the outlet conduit 46 that provides the supply of the component 44. The first mixing junction 56 can also be configured such that the discharge axis of the discharge 64 is co-axial with the outlet axis of the outlet conduit 46. As such, the first mixing junction 56 can be configured such that the axis of the first inlet 60 can be co-axial with the axis of the discharge 64 of the first mixing junction 56. The second inlet 62 providing the second fluid supply 28 to the first mixing junction 56 can be set up to enter the first mixing junction 56 on a side of the first mixing junction 56.

[0261] When configured as an eductor, the first mixing junction 56 can mix the supply of the component 44 from the component feed system 40 with the second fluid supply 28. By transferring the65127350PCT02 KCX-2167-PCT

[0262] second fluid supply 28 into the first mixing junction 56 at the second inlet 62 and through the first mixing junction 56, the second fluid supply 28 provides a motive pressure to the supply of the component 44. The motive pressure can create a vacuum on the supply of the component 44 and the component feed system 40 to help draw the supply of the component 44 to mix and be entrained in the second fluid supply 28. In some embodiments, the motive pressure can create a vacuum on the supply of the component 44 of less than 1.5in Hg, however, in other embodiments, the motive pressure could create a vacuum on the supply of the component 44 of 5in. Hg or more, or 10in Hg or more.

[0263] The pressure control system 50 can help manage proper distribution and entrainment of the supply of the component 44 to the second fluid supply 28. For example, when the second fluid supply 28 creates a motive pressure on the component feed system 40, the vacuum pulling on the supply of the component 44 may cause additional air to be entrained in the second fluid supply 28. In some circumstances, entraining additional air in the second fluid supply 28 may be desired, however, in other circumstances, it may be desirable to control the gas content of the second fluid supply 28 while inputting the supply of the component 44 to the second fluid supply 28 at the first mixing junction 56. For example, in some circumstances where the second fluid supply 28 is a foam, the amount of gas content in the foam may be desired to be kept relatively fixed as the foam passes through the first mixing junction 56 Thus, the pressure control system 50 can control the pressure on the component feed system 40 to help counteract the motive pressure on the supply of the component 44 and the component feed system 40 created by the second fluid supply 28.

[0264] In some embodiments, the pressure control system 50 can include sealing off the component feed system 40. For example, as discussed above, the pressure control system 50 can include a housing 52 to provide a seal on the component feed system 40. Sealing the component feed system 40 can help to prevent additional air entrainment in the second fluid supply 28 when the supply of the component 44 is introduced into the second fluid supply 28 in the first mixing junction 56.

[0265] However, in some embodiments, it may be beneficial to also include additional capability to the pressure control system 50 For example, in some embodiments, the pressure control system 50 can include a bleed orifice 54. The bleed orifice 54 can be configured to bleed-in pressure, such as atmospheric air pressure, to provide additional pressure control of the component feed system 40. It has been discovered that by providing a bleed-in orifice 54 to provide some bleed-in of atmospheric air pressure to the component feed system 40, back-splashing of the second fluid supply 28 in the first mixing junction 56 can be reduced or eliminated. Reducing back-splashing of the second fluid supply 28 in the first mixing junction 56 can help prevent the component feed system 40 from becoming65127350PCT02 KCX-2167-PCT

[0266] clogged or needing to be cleaned, especially where the component feed system 40 may be delivering a dry component, such as particulate SAM.

[0267] Additionally or alternatively, the pressure control system 50 can be configured to provide additional positive pressure to prevent back-filling of the component feed system 40 in some circumstances, such as if a downstream obstruction occurs in the apparatus 11 beyond the first mixing junction 56. In such a case of an obstruction creating an increased pressure, the second fluid supply 28 may have a desire to back-fill the component feed system 40. Back-filling of fluid into the component feed system 40 can be detrimental to processing, especially where the supply of the component 44 is a component best kept in dry conditions, such as SAM. A pressure control system 50 configured to be able to provide positive pressure to the component feed system 40 can help prevent such back-filling of the component feed system 40.

[0268] It is also contemplated that other additional aspects of a pressure control system 50 could be utilized to maintain the pressure to a suitable level for the component feed system 40, including, but not limited to, supplying vacuum to the component feed system 40 in addition to or alternative to the air bleed-in at the bleed orifice 54 and / or the positive pressure described above.

[0269] The first mixing junction 56 can also provide pressure control on the transfer of the second fluid supply 28 including the component 44 as it exits the discharge 64 of the first mixing junction 56 as compared to when the second fluid supply 28 enters the first mixing junction 56. The second fluid supply 28 can be transferred at a second fluid pressure prior to the first mixing junction 56. The second fluid supply 28 including the component from the supply of the component 44 can exit the discharge 64 of the first mixing junction 56 at a discharge pressure. The pressure difference between the second fluid pressure prior to the first mixing junction 56 and the discharge pressure can be controlled. In some embodiments, this pressure difference can be controlled by varying the flow rate of the second fluid supply 28 or through the positioning of the outlet conduit 46 in the first mixing junction 56. In some embodiments, it is preferable to control the pressure difference between the second fluid pressure prior to the first mixing junction 56 and the discharge pressure to be less than or equal to 5 pounds per square inch.

[0270] It is to be noted that while a single outlet conduit 46 of the component feed system 40 and a single first mixing junction 56 is illustrated in FIG. 3, it is contemplated that the outlet conduit 46 can be split into two or more conduits to feed two or more first mixing junctions 56 for mixing the supply of the component 44 with the second fluid supply 28. In such a configuration, the second fluid supply 28 can include as many conduits as there are first mixing junctions 56. By having more than one outlet conduit 46 and more than one first mixing junction 56 to mix the supply of the component 44 with the65127350PCT02 KCX-2167-PCT

[0271] second fluid supply 28, a greater flow rate of the second fluid supply 28 including the component from the supply of the component 44 can be achieved.

[0272] Referring to FIG. 3, the apparatus 11 can include a second mixing junction 58 in some embodiments. The second mixing junction 58 can provide the functionality of mixing the second fluid supply 28 including the component from the supply of the component 44 with the first fluid supply 16. As the second fluid supply 28 including the component from the supply of the component 44 exits the discharge 64 of the first mixing junction 56 it can be transferred to the second mixing junction 58. The first fluid supply 16 can be delivered to the second mixing junction 58 by the first pump 36. The second mixing junction 58 can mix the first fluid supply 16 and any of its components (e.g., fluid 18, fibers 20, surfactant 22) with the second fluid supply 28 and any of its components (e.g., fluid 30, surfactant 32) and the component from the supply of the component 44 to deliver the mixture of the first fluid supply 16, the second fluid supply 28, and the component 44 to a headbox 80.

[0273] Alternatively, in some embodiments, a second mixing junction 58 can be omitted from the apparatus 11 and the second fluid supply 28 including the component from the supply of the component 44 can be delivered to headbox 80.

[0274] As illustrated in FIGS. 4 and 5, the headbox 80 can include one or more z-directional dividers 78a, 78b for separating different inputs to the headbox 80 in forming different layers of the nonwoven material 10. The third fluid supply 33 and any of its components (e.g., fluid 35, fibers 37, surfactant 39) can be delivered to the inlet 81 of the headbox 80 via the third pump 43 and can be delivered above the first z-directional divider 78a in a first z-directional zone 85a of the headbox 80. The output of the second mixing junction 58 including the mixture of the first fluid supply 16 and any of its components (e.g., fluid 18, fibers 20, surfactant 22), the second fluid supply 28 and any of its components (e.g., fluid 30, surfactant 32), and the component 44 can be delivered to the inlet 81 of the headbox 80 below the first z-directional divider 78a and above the second z-directional divider 78b in a second z-directional zone 85b of the headbox 80. The fourth fluid supply 68 and any of its components (e.g., fluid 69, fibers 70, surfactant 71) can be delivered to the inlet 81 of the headbox 80 via the fourth pump 73 and can be delivered below the second z-directional divider 78b in a third z-directional zone 85c of the headbox 80. Such a configuration of two z-directional dividers 78a, 78b can be beneficial for forming a three-layered substrate 10, such as described above and illustrated in FIG. 2.

[0275] The headbox 80 can provide a resultant slurry 76 to a forming surface 94. The forming surface 94 can be a foraminous sheet, such as a woven belt or screen, or any other suitable surface for accepting the resultant slurry 76.

[0276] The apparatus 11 can also include a dewatering system 96 that can be configured to remove liquid from the resultant slurry 76 (e.g., forming fluid) on the forming surface 94. In some65127350PCT02 KCX-2167-PCT

[0277] embodiments, the dewatering system 96 can be configured to provide a vacuum to the resultant slurry 76 to pull liquid from the resultant slurry 76, and in doing so, can turn the resultant slurry 76 including the plurality of fibers 20 and the component 44, if present, into a multi-layer substrate 10. In some embodiments, the dewatering system 96 can begin dewatering on fibers and / or components as they are still within the headbox 80.

[0278] Dewatering systems 96 drawing liquid from the resultant slurry 76 can also unintentionally draw components 44 (such as particulate SAM) through the forming surface 94, and / or cause components 44 to become lodged in the forming surface 94. Not only can this cause substrates 10 to be formed that do not include intended amounts of the component 44, but components 44 becoming lodged in the forming surface 94 and / or being drawn through the forming surface 94 can cause processing issues, including, but not limited to, reduced dewatering and / or increased demands for drying of the resultant slurry 76, machine down-time for cleaning, and increased complexity for dewatered liquid by including such components 44. Forming a multi-layer substrate 10 including components 44 in a fluid, such as foam forming, can exacerbate the problem of component 44 movement in the resultant slurry 76 in comparison to dry forming techniques, such as air-laid formation techniques or adhesive-based techniques.

[0279] Forming a distribution layer 17 as part of the substrate 10 that is directly against the forming surface 94 can help protect the components 44 of the substrate 12 (such as SAM in the retention layer 13). The distribution layer 17 can protect the components 44 of the substrate 10 from the forming surface to help ensure the components 44 remain in the substrate 10, or at least reduce the possibility for the components 44 to become lodged in the forming surface 94 or be drawn through the forming surface 94. Additionally, the distribution layer 17 can help retain components 44 within the absorbent material 10 as it is potentially transported for further processing and / or use in other products in which the multi-layer substrate 10 may be incorporated within, such as personal care absorbent articles. Forming the distribution layer 17 inline as a composite with the retention layer 13 where at least some fibers of the distribution layer 17 are mixed with at least some of the fibers of the retention layer 13 at the interface 19, eliminates the need for additional processing to form a composite absorbent substrate 10, such as the use of adhesive to couple a separate distribution layer 17 to a retention layer 13. Eliminating adhesive can result in reduced processing equipment and raw material cost and can also lead to improved fluid handling properties of the absorbent substrate 10. Additionally, forming a distribution layer 17 as part of the substrate 10 can also provide improved integrity and tensile strength for the absorbent material 10 providing enhanced processing capability of the substrate 10.

[0280] While the apparatus 11 and method described in FIG. 3 is one exemplary embodiment for forming a multi-layer substrate 10, an alternative embodiment of an apparatus 111 and method of65127350PCT02 KCX-2167-PCT

[0281] forming a multi-layer substrate 10 is depicted in FIG. 5. The apparatus 111 of FIG. 5 can be used as part of a similar foam forming process as described above with respect to FIG. 3, however, the headbox 180 is a vertical twin former as is known in the art. The headbox 180 can include first and second foraminous elements 119, 121. The first and second foraminous elements 119, 121 can help define an interior volume of the headbox 180. The headbox 180 can include a first divider 178a and a second divider 178b that can provide first, second, and third z-directional zones 185a, 185b, 185c within the headbox 180 similar to the discussion above with the headbox 80 in FIG. 4, but the zones 185a, 185b, 185c in FIG. 5 are in a vertical orientation with respect to one another due to the vertical orientation of the headbox 180. The apparatus 111 can include a dewatering system 196 that can include a series of vacuum elements 197 disposed adjacent each foraminous element 119, 121.

[0282] In some embodiments, a first supply of fibers 20 can be supplied to the headbox 180, and in some embodiments, the first supply of fibers 20 can be in a foam. The supply of the fibers 20 can include at least some absorbent fibers. The supply of the component 44 can also be supplied directly to the headbox 180, and in some embodiments, the supply of the component 44 may be in a foam. The supply of the fibers 20 and component 44 can be delivered to the second z-directional zone 185b of the headbox 180. It is to be noted that in some embodiments, the second z-directional zone 185b of the headbox 180 may only be provided with the supply of the component 44 and not a supply of fibers 20. In some embodiments, a second supply of fibers 123 can be provided to the headbox 180, and in some embodiments, can be in a foam. The second supply of fibers 123 can be provided to the first z-directional zone 185a of the headbox 180. In some embodiments, a third supply of fibers 125 can be provided to the headbox 180, and in some embodiments, can be in a foam. The third supply of fibers 125 can be provided to the third z-directional zone 185c of the headbox 180. The fibers 20, 123, 125 and component 44 can be processed through the headbox 180 in a machine direction 185 towards the outlet 182 of the headbox 180 to provide an absorbent material 10, similar to the apparatus 11 described in FIG. 3.

[0283] The apparatuses 11, 111 as described herein can also include a drying system 98 to further dry and / or cure the absorbent material 10. The drying system 98 can apply heat to the absorbent material 10, such as by providing heated air in a through-air drying system.

[0284] In some embodiments, the apparatus 11, 111 can include a winding system 99 (as shown in FIG. 3) that can be configured to wind the absorbent material 10 in a roll fashion. In other embodiments, the apparatus 11, 111 can festoon the absorbent material 10 or collect the absorbent material 10 in any other suitable configuration, such as spooling.

[0285] As described above, the foam forming processes as described herein can include a foaming fluid. In some embodiments, the foaming fluid can comprise between about 85% to about 99.99% of65127350PCT02 KCX-2167-PCT

[0286] the foam (by weight). In some embodiments, the foaming fluid used to make the foam can comprise at least about 85% of the foam (by weight). In certain embodiments, the foaming fluid can comprise between about 90% and about 99.9% % of the foam (by weight). In certain other embodiments, the foaming fluid can comprise between about 93% and 99.5% of the foam or even between about 95% and about 99.0% of the foam (by weight). In preferred embodiments, the foaming fluid can be water, however, it is contemplated that other processes may utilize other foaming fluids.

[0287] The foam forming processes as described herein can utilize one or more surfactants. The fibers and surfactant, together with the foaming liquid and any additional components, can form a stable dispersion capable of substantially retaining a high degree of porosity for longer than the drying process. In this regard, the surfactant is selected so as to provide a foam having a foam half life of at least 2 minutes, more desirably at least 5 minutes, and most desirably at least 10 minutes. A foam half life can be a function of surfactant types, surfactant concentrations, foam compositions / solid level and mixing power / air content in a foam. The foaming surfactant used in the foam can be selected from one or more known in the art that are capable of providing the desired degree of foam stability. In this regard, the foaming surfactant can be selected from anionic, cationic, nonionic and amphoteric surfactants provided they, alone or in combination with other components, provide the necessary foam stability, or foam half life. As will be appreciated, more than one surfactant can be used, including different types of surfactants, as long as they are compatible, and more than one surfactant of the same type. For example, a combination of a cationic surfactant and a nonionic surfactant or a combination of an anionic surfactant and a nonionic surfactant may be used in some embodiments due to their compatibilities. However, in some embodiments, a combination of a cationic surfactant and an anionic surfactant may not be satisfactory to combine due to incompatibilities between the surfactants. In one aspect, a primary surfactant may be used to produce a foam and a secondary surfactant can be applied to the nonwoven material during processing.

[0288] Anionic surfactants believed suitable for use with the present disclosure include, without limitation, anionic sulfate surfactants, alkyl ether sulfonates, alkylaryl sulfonates, or mixtures or combinations thereof. Examples of alkylaryl sulfonates include, without limitation, alkyl benzene sulfonic acids and their salts, dialkylbenzene disulfonic acids and their salts, dialkylbenzene sulfonic acids and their salts, alkylphenol sulfonic acids / condensed alkylphenol sulfonic acids and their salts, or mixture or combinations thereof. Examples of additional anionic surfactants believed suitable for use in the present disclosure include alkali metal sulforicinates, sulfonated glyceryl esters of fatty acids such as sulfonated monoglycerides of coconut oil acids, salts of sulfonated monovalent alcohol esters such as sodium oleylisethianate, metal soaps of fatty acids, amides of amino sulfonic acids such as the sodium salt of oleyl methyl tauride, sulfonated products of fatty acids nitriles such as palmitonitrile65127350PCT02 KCX-2167-PCT

[0289] sulfonate, alkali metal alkyl sulfates such as sodium lauryl sulfate, ammonium lauryl sulfate or triethanolamine lauryl sulfate, ether sulfates having alkyl groups of 8 or more carbon atoms such as sodium lauryl ether sulfate, ammonium lauryl ether sulfate, sodium alkyl aryl ether sulfates, and ammonium alkyl aryl ether sulfates, sulphuric esters of polyoxyethylene alkyl ether, sodium salts, potassium salts, and amine salts of alkylnapthylsulfonic acid. Certain phosphate surfactants including phosphate esters such as sodium lauryl phosphate esters or those available from the Dow Chemical Company under the tradename TRITON are also believed suitable for use herewith. A particularly desired anionic surfactant is sodium dodecyl sulfate (SDS).

[0290] Cationic surfactants are also believed suitable for use with the present disclosure for manufacturing some embodiments of substrates. In some embodiments, such as those including superabsorbent material, cationic surfactants may be less preferable to use due to potential interaction between the cationic surfactant(s) and the superabsorbent material, which may be anionic. Foaming cationic surfactants include, without limitation, monocarbyl ammonium salts, dicarbyl ammonium salts, tricarbyl ammonium salts, monocarbyl phosphonium salts, dicarbyl phosphonium salts, tricarbyl phosphonium salts, carbylcarboxy salts, quaternary ammonium salts, imidazolines, ethoxylated amines, quaternary phospholipids and so forth. Examples of additional cationic surfactants include various fatty acid amines and amides and their derivatives, and the salts of the fatty acid amines and amides. Examples of aliphatic fatty acid amines include dodecylamine acetate, octadecylamine acetate, and acetates of the amines of tallow fatty acids, homologues of aromatic amines having fatty acids such as dodecylanalin, fatty amides derived from aliphatic diamines such as undecylimidazoline, fatty amides derived from aliphatic diamines such as undecylimidazoline, fatty amides derived from disubstituted amines such as oleylaminodiethylamine, derivatives of ethylene diamine, quaternary ammonium compounds and their salts which are exemplified by tallow trimethyl ammonium chloride, dioctadecyldimethyl ammonium chloride, didodecyldimethyl ammonium chloride, dihexadecyl ammonium chloride, alkyltrimethylammonium hydroxides, dioctadecyldimethylammonium hydroxide, tallow trimethylammonium hydroxide, trimethylammonium hydroxide, methylpolyoxyethylene cocoammonium chloride, and dipalmityl hydroxyethylammonium methosulfate, amide derivatives of amino alcohols such as beta-hydroxylethylstearylamide, and amine salts of long chain fatty acids. Further examples of cationic surfactants believed suitable for use with the present disclosure include benzalkonium chloride, benzethonium chloride, cetrimonium bromide, distearyldimethylammonium chloride, tetramethylammonium hydroxide, and so forth.

[0291] Nonionic surfactants believed suitable for use in the present disclosure include, without limitation, condensates of ethylene oxide with a long chain fatty alcohol or fatty acid, condensates of ethylene oxide with an amine or an amide, condensation products of ethylene and propylene oxides,65127350PCT02 KCX-2167-PCT

[0292] fatty acid alkylol amide and fatty amine oxides. Various additional examples of non-ionic surfactants include stearyl alcohol, sorbitan monostearate, octyl glucoside, octaethylene glycol monododecyl ether, lauryl glucoside, cetyl alcohol, cocamide MEA, monolaurin, polyoxyalkylene alkyl ethers such as polyethylene glycol long chain (12-14C) alkyl ether, polyoxyalkylene sorbitan ethers, polyoxyalkylene alkoxylate esters, polyoxyalkylene alkylphenol ethers, ethylene glycol propylene glycol copolymers, polyvinyl alcohol, alkylpolysaccharides, polyethylene glycol sorbitan monooleate, octylphenol ethylene oxide, and so forth. Non-ionic surfactants may be preferable when foam forming absorbent materials 10 with SAM. If there is residual ionic surfactant, the increase in ionic strength in the insult can reduce SAM swelling for use of the absorbent materials 10 in personal care absorbent articles.

[0293] The foaming surfactant can be used in varying amounts as necessary to achieve the desired foam stability and air-content in the foam. In certain embodiments, the foaming surfactant can comprise between about 0.005% and about 5% of the foam (by weight). In certain embodiments the foaming surfactant can comprise between about 0.05% and about 3% of the foam or even between about 0.05% and about 2% of the foam (by weight).

[0294] As noted above, the apparatus 11, 111 and methods described herein can include providing a fibers from a supply of fibers 20, 37, 70, 123, 125. In some embodiments, the fibers can be suspending in a fluid supply 16, 28, 33, 68 that can be a foam. The foam suspension of fibers can provide one or more supply of fibers. As described above, fibers utilized herein can include cellulose fibers and / or synthetic fibers. In some embodiments, a fiber supply 20, 37, 70, 123, 125 can include only cellulose fibers or only synthetic fibers. In other embodiments, a fiber supply 20, 37, 70, 123, 125 can include a mixture of cellulose fibers, binder fibers and / or synthetic fibers. Some fibers being utilized herein can be absorbent, whereas other fibers utilized herein can be non-absorbent. Nonabsorbent fibers can provide features for the substrates that are formed from the methods and apparatuses described herein, such as improved intake or distribution of fluids.

[0295] In some embodiments, a fluid supply 16, 28, 33, 68 can include binder fibers (as described above) that can be provided along with or independent of the supply of the fibers 20, 37, 70, 123, 125 or the supply of the component 44.

[0296] Binder fibers, when used, may be added proportionally to the other components to achieve the desired fiber ratios and structure while maintaining the total solids content of the foam below the amounts stated above. As an example, in some embodiments, binder fibers can comprise between about 0% and about 80% of the total fiber weight, and more preferably, between about 5% to about 40% of the total fiber weight in some embodiments.

[0297] In some embodiments, if a fluid supply 16, 28, 33, 68 is configured as a foam the foam may optionally also include one or more foam stabilizers known in the art and that are compatible with the65127350PCT02 KCX-2167-PCT

[0298] components of the foam and further do not interfere with the hydrogen bonding as between the cellulosic fibers. Foam stabilizing agents believed suitable for use in the present disclosure, without limitation, one or more zwitterionic compounds, amine oxides, alkylated polyalkylene oxides, or mixture or combinations thereof. Specific examples of foam stabilizers includes, without limitation, cocoamine oxide, isononyldimethylamine oxide, n-dodecyldimethylamine oxide, and so forth.

[0299] In some embodiments, if utilized, the foam stabilizer can comprise between about 0.01% and about 2 % of the foam (by weight). In certain embodiments, the foam stabilizer can comprise between about 0.05% and 1% of the foam or even between about 0.1 and about 0.5% of the foam (by weight).

[0300] As mentioned above, foam forming processes can include adding one or more components 44 as additional additives that will be incorporated into the absorbent material 10, such as SAM. In some embodiments incorporating SAM, the SAM can comprise between about 0% and about 40% of the foam (by weight). In certain embodiments, SAM can comprise between about 1% and about 30% of the foam (by weight) or even between about 10% and about 30% of the foam (by weight).

[0301] If used, wet and dry strength additives can comprise between about 0.01 and about 5% of the dry weight of cellulose fibers. In certain embodiments, the strength additives can comprise between about 0.05% and about 2% of the dry weight of cellulose fibers or even between about 0.1 % and about 1 % of the dry weight of cellulose fibers.

[0302] When employed, miscellaneous components that may also be used in the absorbent material (as described above, such as, pigments, anti-microbial agents, etc.) can desirably comprise less than about 2% of the foam (by weight) and still more desirably less than about 1 % of the foam (by weight) and even less than about 0.5% of the foam (by weight).

[0303] In some embodiments, the solids content, including the fibers or particulates contained herein, desirably comprise no more than about 40% of the foam. In certain embodiments the cellulosic fibers can comprise between about 0.1% and about 5% of the foam or between about 0.2 and about 4% of the foam or even between about 0.5% and about 2% of the foam.

[0304] The nonwoven webs or absorbent substrates as described above can be incorporated into numerous different absorbent articles including the feminine hygiene products as shown in FIG. 1 In one aspect, the absorbent substrate incorporated into products of the present disclosure are relatively thin while having excellent absorbency properties. For instance, the absorbent substrate can have a thickness of less than about 6 mm, such as less than about 5 mm, such as less than about 4.5 mm, such as less than about 4 mm.

[0305] As described above, absorbent substrates made according to the present disclosure are designed to rapidly intake and hold different fluids, such as fluids with different viscosities. For instance, the absorbent substrate of the present disclosure not only rapidly absorbs and holds urine65127350PCT02 KCX-2167-PCT

[0306] but also rapidly absorbs and holds menses. In this regard, absorbent substrates made according to the present disclosure can display excellent properties when tested according to the FIUP Test, which simulates urine absorption, and according to the Heated Intake Test, which simulates menses absorption.

[0307] During the FIUP Test, the absorbent substrate is insulted with a saline solution three different times. The amount of the saline solution during each insult can be 24 mL or 8 mL. During the test, intake times can be recorded and an amount known as rewet can be measured and recorded.

[0308] Absorbent substrates made according to the present disclosure, when tested according to the FIUP Test at 25 mL per insult, can display a first intake time of less than about 20 seconds, such as less than about 15 seconds. The second intake time can be less than about 30 seconds, such as less than about 25 seconds. The third intake time can be less than about 100 seconds, such as less than about 80 seconds, such as less than about 60 seconds, such as less than about 50 seconds. The rewet can be less than about 1 g.

[0309] Absorbent substrates made according to the present disclosure when tested according to the FIUP Test at 8 mL per insult can also display the above intake times. Of particular advantage, absorbent substrates can display a rewet at less than 1 g.

[0310] When tested according to the Heated Intake Test, the absorbent substrate can display a gush time of less than about 20 seconds, such as less than about 15 seconds and can display a rewet of less than about 1.0 g.

[0311] In addition to having excellent fluid handling properties, the absorbent article can be very flexible. For instance, when tested according to the Horizontal Side Compression Test, the absorbent article can display an energy after one cycle of less than of less than about 2,000 gFcm, such as less than about 1,600 gFcm, such as less than about 1,500 gFcm, such as less than about 1,200 gFcm, such as less than about 1,000 gFcm. The absorbent article can display a width recovery of greater than about 80%, such as greater than about 82%, such as greater than about 84%, such as greater than about 85%, and less than about 99%.

[0312] The present disclosure may be better understood with reference to the following examples.

[0313] Example No. 1

[0314] In the examples below, a multi-layer nonwoven material or absorbent substrate was produced. The multi-layer absorbent substrate was produced using a foam forming process as described above. Each sample that was made was treated with a surfactant blend in an amount of 0.3 gsm. The surfactant was a mixture of a non-ionic surfactant and an anionic surfactant. The surfactant was applied to the intake layer after drying. The following absorbent substrates were produced:Table 1

[0315] Intake Layer Retention Layer Distribution Layer Eccentric

[0316] Target Total PET 13 Bico 2.2 Fiber Bico 2.2 Fiber SAM BW Bico 1 3 Fiber Sample Bico 6.7 CMC- SBSK CMC- Basis Weight dtex, dtex, 6mm BW dtex, BW (gsm) dtex, BW No dtex, 6mm 535 (%) (%) 535 (%) (gsm) 6mm (%) (%) (gsm) 6mm (%) (gsm) LK601N 6mm (%) (gsm)

[0317] (%)

[0318] 3 450 40 45 15 50 85 15 120 250 40 40 20 30 4 500 40 45 15 50 85 15 120 300 40 40 20 30 5 515 40 45 15 50 85 15 120 315 40 40 20 30 6 400 40 45 15 50 85 15 120 200 40 40 20 30 7 430 40 45 15 50 85 15 100 250 40 40 20 30 8 480 40 45 15 50 85 15 100 300 40 40 20 30 9 495 40 45 15 50 85 15 100 315 40 40 20 30 10 380 40 45 15 50 85 15 100 200 40 40 20 30 11 415 40 45 15 50 85 15 85 250 40 40 20 30 12 405 40 45 15 40 85 15 85 250 40 40 20 30 13 365 40 45 15 50 85 15 85 200 40 40 20 30 14 355 40 45 15 40 85 15 85 200 40 40 20 30 15 340 40 45 15 50 85 15 85 175 40 40 20 30 16 330 40 45 15 40 85 15 85 175 40 40 20 30 17 315 40 45 15 50 85 15 85 150 40 40 20 30 18 305 40 45 15 40 85 15 85 150 40 40 20 30 19 285 40 45 15 50 85 15 85 120 40 40 20 30

[0319]

[0320] 20 275 40 45 15 40 85 15 85 120 40 40 20 3065127350US01 KCX-2167-P

[0321] The superabsorbent material (SAM) was commercially available as LK601N superabsorbent manufactured by LG. The binder fibers used had a polyethylene / PET sheath / core structure. The crosslinked pulp fiber used was obtained from International Paper.

[0322] In addition to the above, two other samples were produced (Sample Nos. 1 and 2). Sample Nos. 1 and 2 had a resilient fiber to superabsorbent material ratio of less than 0.2. These samples were produced for comparative reasons.

[0323] The samples produced were tested for various properties including packing density and superabsorbent material spacing. The samples were also subjected to the Heated Intake Test and the FIUP Test. The following results were obtained.

[0324] Table No. 2

[0325] Sample SAM Add-on

[0326] CMC / SAM Ratio Packing Density SAM spacing (urn) No. (gsm)

[0327] 1 415 0.12 0.064 423.5 2 315 0.16 0.059 525.8 3 250 0.41 0.05 558.6 4 300 0.34 0.048 616.1 5 315 0.32 0.051 486.5 6 200 0.51 0.033 900.8 7 250 0.34 0.038 743.9 8 300 0.28 0.044 622.3 10 200 0.43 0.037 806.8

[0328]

[0329] Table No. 3: Heated Intake Test

[0330] Heated Intake- Whole Product Whole Product

[0331] Sample No. Ratio CMC / SAM Gush Intake Time Rewet (g)

[0332] Saturation (g) Retention (g)

[0333] (sec)

[0334] 1 0.12 Not tested Not tested 47.0 0.88 2 0.16 Not tested Not tested 24.2 0.82 3 0.41 140 92.7 13.72 0.72 4 0.34 152 102 13.13 0.6 5 0.32 141 97.8 13.98 0.58 6 0.51 143 89 10.73 0.83 7 0.34 137 95.3 12.67 0.72 8 0.28 139 101 12.69 0.52 9 0.27 136 99.4 14.61 0.55 10 0.43 125 83.7 11.17 0.76

[0335]

[0336] Table No. 4: FIUP Test, 25 ml_ per insult, and Horizontal Side Compression Test Results

[0337] Dry

[0338] Retention FIUP FIUP FIUP Compression Width Sample Ratio Thickness

[0339] Capacity 1stIntake 2ndIntake 3rdIntake Rewet (g) Energy- Cycle 1 Recovery No. CMC / SAM Center

[0340] (g) Time (sec) Time (sec) Time (sec) (gf'cm) (%)

[0341] (mm)

[0342] 3 0.41 128 13.53 22.73 51.33 0.68 4.33 1294 88.23 4 0.34 142 13.87 25.3 46.33 0.25 4.4 1638 88.9 5 0.32 145 13.63 31.4 59.03 0.15 4.43 1579 89 6 0.51 113 14.13 23.33 46.1 0.68 4.27 1533 84.93 7 0.34 126 14.27 28.93 57.97 0.25 4.27 1540 92.17 8 0.28 145 13.77 23.87 49.07 0.16 4.17 1564 89.87 9 0.27 143 13.47 23.97 42.53 0.2 4.13 1869 89.7

[0343]

[0344] 10 0.43 109 14.33 25.73 54.17 0.85 4.04 1498 88.83Table No. 5: Heated Intake Test Results

[0345] Whole Product Capacity Heated Intake / Rewet

[0346] Menses Menses

[0347] Sample Total BW SAM add-on Ratio Gush Intake Saturation Retention Rewet (g) No. (gsm) (gsm) CMC / SAM Time (sec)

[0348] (g) (g)

[0349] 11 415 250 0.29 121 87 16.9 0.77 12 405 250 0.29 110 80 19.7 0.85 13 365 200 0.36 106 76 13.2 0.87 14 355 200 0.36 107 76 17.8 1.00 15 340 175 0.41 100 72 16.2 1.21 16 330 175 0.41 99 68 19.3 1.00 17 315 150 0.48 105 70 14.2 1.12 18 305 150 0.48 106 70 17.1 0.93 19 285 120 0.6 98 62 19.9 1.33 20 275 120 0.6 94 61 19 1.28 STAYFREE UT regular pad 80 49 19.6 1.17

[0350]

[0351] STAYFREE UT overnight pad 133 81 13 1.7765127350US01 KCX-2167-P

[0352] As shown above, the absorbent substrates of the present disclosure were tested in comparison to commercial products.Table No. 6: FIUP Test, 25 mL per insult, and Horizontal Side Compression Test Results

[0353] SAM Retention FIUP FIUP FIUP Dry Compression Width Ratio

[0354] Sample No. Add-on Capacity 1stIntake 2ndIntake 3rdIntake Rewet (g) Thickness Energy- Cycle 1 Recovery CMC / SAM

[0355] (gsm) (g) Time (sec) Time (sec) Time (sec) Center (mm) (gf'cm) (%) 11 250 0.29 124 152 28.9 61.9 0.27 3.83 1413 84 12 250 0.29 126 159 31.9 70.2 0.53 3.9 1431 87 13 200 0.36 110 148 23.8 56.2 0.85 3.97 1541 86 14 200 0.36 105 16.2 30.4 67.1 1.19 3.9 1258 84 15 175 0.41 99 13.9 24.4 66.1 2.52 4.1 1444 87 16 175 0.41 99 17.4 34 143 5.15 4.03 1197 83 STAYFREE

[0356] 90 22 47.1 >300 leaked 3.65 1517 77

[0357]

[0358] UT overnight65127350US01 KCX-2167-P

[0359] Example No. 2

[0360] Further absorbent substrates were made in accordance with the present disclosure and subjected to the FIUP Test at 8 mL per insult. The substrates were made according to the same process as explained in Example No. 1. The following substrates were made and the following results were obtained:Table No. 7

[0361] Intake Layer Retention Layer Distribution Layer Total Eccentric Bico 2.2 SAM bone

[0362] Bico 2.2 Fiber Fiber Bico 1.3 Fiber Sample Basis Ratio PET 13 dtex, Bico 6.7 CMC- dtex, dry BW SBSK CMC- dtex, 6mm BW BW dtex, BW No. Weight CMC / SAM 6mm (%) dtex, 6mm 535 (%) 6mm (gsm) (%) 535 (%)

[0363] (%) (gsm) (gsm) 6mm (%) (gsm) target (gsm) (%) (%) LK601N

[0364] 21 480 0.28 40 45 15 50 85 15 100 300 40 40 20 30 22 430 0.34 40 45 15 50 85 15 100 250 40 40 20 30 23 380 0.43 40 45 15 50 85 15 100 200 40 40 20 30 24 355 0.49 40 45 15 50 85 15 100 175 40 40 20 30

[0365]

[0366] 25 330 0.57 40 45 15 50 85 15 100 150 40 40 20 30

[0367] Table No. 8

[0368] FIUP FIUP FIUP Dry

[0369] Sample SAM Add-on Ratio Rewet Retention

[0370] 1stIntake 2ndIntake 3rdIntake Thickness

[0371] No. (gsm) CMC / SAM Capacity (g)

[0372] Time (sec) Time (sec) Time (sec) (g) (mm)

[0373] 21 300 0.28 8.93 9.03 10.8 0.05 4.4 143

[0374] 22 250 0.34 8.93 9.03 10.1 0.09 4.57 122

[0375] 23 200 0.43 8.9 8.97 9.3 0.44 4.57 109

[0376] 24 175 0.49 8.54 8.7 9.24 0.9 3.92 95

[0377]

[0378] 25 150 0.57 8.8 8.97 9.4 1.52 4.37 8665127350US01 KCX-2167-P

[0379] These and other modifications and variations to the present invention may be practiced by those of ordinary skill in the art, without departing from the spirit and scope of the present invention, which is more particularly set forth in the appended claims. In addition, it should be understood that aspects of the various embodiments may be interchanged both in whole or in part. Furthermore, those of ordinary skill in the art will appreciate that the foregoing description is by way of example only, and is not intended to limit the invention so further described in such appended claims.

Claims

65127350US01 KCX-2167-PWhat Is Claimed:

1. An absorbent substrate comprising:an intake layer;a retention layer; anda distribution layer, the retention layer disposed between the intake layer and the distribution layer; andwherein the absorbent substrate displays a third intake of less than 100 seconds when tested according to the FIUP Test at 25 mL per insult, and wherein the absorbent substrate has a menses intake of less than 20 seconds when tested according to the Heated Intake Test.

2. The absorbent substrate of claim 1, wherein the retention layer includes resilient fibers blended with a superabsorbent material and wherein a ratio of the resilient fibers to superabsorbent material is between about 0.25 and about 0.59, such as between about 0.27 and about 0.55.

3. The absorbent substrate of claim 2, wherein the resilient fiber includes at least one of a crosslinked cellulose fiber, a regenerated cellulose fiber, a synthetic fiber such as polyester fibers, polylactic acid fibers, polyhydroxyalkanoate fibers, or polypropylene fibers.

4. The absorbent substrate of claim 1, wherein the retention layer includes resilient fibers blended with a superabsorbent material and wherein the superabsorbent material spacing in the retention layer is between about 480 microns to about 1,300 microns, such as from about 550 microns to about 1,300 microns.

5. The absorbent substrate of claim 1, wherein the absorbent substrate has a basis weight of between about 250 gsm to about 900 gsm.

6. The absorbent substrate of claim 1, wherein at least some fibers of the intake layer are mixed with at least some of the fibers of the retention layer.

7. The absorbent substrate of claim 1, wherein the absorbent substrate is foam formed.

8. The absorbent substrate of claim 1, wherein the menses rewet is less than 1 g.

9. The absorbent substrate of claim 1, wherein, when tested according to the FIUP Test at 8 mL per insult, the absorbent substrate displays a rewet of less than 1 g.

10. The absorbent substrate of claim 1, wherein the intake layer comprises synthetic fibers and binder fibers, the binder fibers being present in the intake layer in an amount from about 30% by weight to about 75% by weight, such as in an amount from about 40% by weight to about 65% by weight, the intake layer having a basis weight of from about 25 gsm to about 65 gsm, such as from about 30 gsm to about 60 gsm.

11. The absorbent substrate of claim 1, wherein the distribution layer comprises binder fibers combined with cellulose fibers, the binder fibers being present in the distribution layer in an65127350US01 KCX-2167-Pamount from about 10% by weight to about 55% by weight, such as in an amount from about 25% by weight to about 50% by weight, the distribution layer having a basis weight of from about 15 gsm to about 65 gsm, such as from about 20 gsm to about 50 gsm.

12. The absorbent substrate of claim 1, wherein the absorbent substrate displays a first intake of less than 15 seconds, when tested according to the FIUP Test.

13. The absorbent substrate of claim 1, wherein the absorbent substrate displays a second intake of less than 25 seconds, when tested according to the FIUP Test.

14. The absorbent substrate of claim 2, wherein the retention layer contains the superabsorbent material in an amount greater than about 180 gsm, such as in an amount greater than about 190 gsm.

15. The absorbent substrate of claim 4, wherein the retention layer displays a packing density of from about 0.02 to about 0.055.

16. An absorbent substrate comprising:an intake layer;a retention layer; anda distribution layer, the retention layer disposed between the intake layer and the distribution layer;wherein the absorbent substrate displays a third intake of less than 100 seconds when tested according to the FIUP Test at 25 mL per insult, and wherein the absorbent substrate displays a rewet of less than 1.0 g when tested according to the FIUP Test at 8 mL per insult.

17. The absorbent substrate of claim 16, wherein the retention layer includes resilient fibers blended with a superabsorbent material and wherein a ratio of the resilient fibers to superabsorbent material is between about 0.25 and about 0.59, such as between about 0.27 and about 0.55.

18. The absorbent substrate of claim 17, wherein the resilient fibers include at least one of a crosslinked cellulose fiber, a regenerated cellulose fiber, a synthetic fiber such as polyester fibers, polylactic acid fibers, polyhydroxyalkanoate fibers, or polypropylene fibers19. The absorbent substrate of claim 16, wherein the retention layer includes resilient fibers blended with a superabsorbent material and wherein the superabsorbent material spacing in the retention layer is between about 480 microns to about 1,300 microns, such as from about 550 microns to about 1,300 microns.

20. The absorbent substrate of claim 16, wherein the absorbent substrate is foam formed.

21. The absorbent substrate of claim 16, wherein the menses rewet is less than 1 g when tested according to the Heated Intake Test.65127350US01 KCX-2167-P22. The absorbent substrate of claim 16, wherein the intake layer comprises synthetic fibers and binder fibers, the binder fibers being present in the intake layer in an amount from about 30% by weight to about 75% by weight, such as in an amount from about 40% by weight to about 65% by weight, the intake layer having a basis weight of from about 25 gsm to about 65 gsm, such as from about 30 gsm to about 60 gsm.

23. The absorbent substrate of claim 16, wherein the distribution layer comprises binder fibers combined with cellulose fibers, the binder fibers being present in the distribution layer in an amount from about 10% by weight to about 55% by weight, such as in an amount from about 25% by weight to about 50% by weight, the distribution layer having a basis weight of from about 15 gsm to about 65 gsm, such as from about 20 gsm to about 50 gsm.

24. The absorbent substrate of claim 17, wherein the retention layer contains the superabsorbent material in an amount greater than about 175 gsm, such as in an amount greater than about 180 gsm.

25. The absorbent substrate of claim 16, wherein the retention layer displays a packing density of from about 0.02 to about 0.055.

26. An absorbent substrate comprising:an intake layer comprising synthetic fibers and binder fibers;a retention layer comprising superabsorbent material, binder fibers, and resilient fibers, wherein a ratio of the resilient fibers to the superabsorbent material is between about 0.25 to about 0.59;a distribution layer, the retention layer disposed between the intake layer and the distribution layer, wherein the distribution layer comprises cellulosic fibers and binder fibers.

27. The absorbent substrate of claim 26, wherein the resilient fibers comprise crosslinked cellulose fibers.

28. The absorbent substrate of claim 26, wherein the superabsorbent material spacing in the retention layer is between about 480 microns to about 1,300 microns, such as from about 550 microns to about 1,300 microns.

29. The absorbent substrate of claim 26, wherein the absorbent substrate has a basis weight of between about 250 gsm to about 900 gsm.

30. The absorbent substrate of claim 26, wherein the absorbent substrate is foam formed.

31. The absorbent substrate of claim 26, wherein the absorbent substrate displays a third intake of less than 60 seconds when tested according to the FIUP Test at 25 mL per insult and displays a rewet of less than 1 g when tested according to the FIUP Test at 8 mL per insult, and65127350US01 KCX-2167-Pwherein the absorbent substrate has a menses intake of less than 20 seconds when tested according to the Heated Intake Test.

32. The absorbent substrate of claim 26, wherein the retention layer contains the superabsorbent material in an amount greater than about 175 gsm, such as in an amount greater than about 180 gsm.

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