Absorbent composite having improved fluid intake and methods of producing absorbent composite

Abstract

The present disclosure relates to a composite and an absorbent core including a composite that facilitates rapid intake of fluid. The composite includes a mixture of superabsorbent particles and adhesive having specific properties that provide hydrophilic properties throughout the surface area of the composite. The composite has a total surface energy greater than 122 mj / m2 and a basicity constant greater than 0.78 at 1 % surface coverage. The composite has improved surface wetting and osmotic swelling of the superabsorbent particles for rapid fluid intake.

Description

PATENT Attorney Docket No.: 109296-1425315 ABSORBENT COMPOSITE HAVING IMPROVED FLUID INTAKE AND METHODS OF PRODUCING ABSORBENT COMPOSITE FIELD 5

[0001] The present disclosure generally relates to absorbent composites and methods of producing absorbent composites. In particular, the present disclosure relates to an absorbent composite including a mixture of superabsorbent material and adhesive having surface properties that improve initial surface wetting and liquid intake time in response to an insult. The absorbent composite can be used in absorbent articles, for example, diapers, training pants, adult 10 incontinence products, bodily-exudates absorbing products, feminine hygiene products, and other absorbent products. BACKGROUND

[0002] Absorbent articles such as diapers, incontinence garments, sanitary napkins, 15 and menstrual pads, are designed to absorb and retain liquid and other discharges from the human body to prevent soiling of the body and clothing. Absorbent articles should provide adequate leakage protection for healthy, dry skin. To prevent leakage, the absorbent article should provide rapid intake of fluid (e.g., urine) into the absorbent core of the absorbent article and retain the fluid therein. If the fluid is not rapidly absorbed within the absorbent core of the 20 absorbent article, fluid may leak or reach other unwanted surfaces of the absorbent article. This can cause direct contact between fluids and a user’s skin, which can result in overhydration of the skin, rendering it susceptible to irritation, infection, and uncomfortable wearability.

[0003] To provide rapid intake of fluid, the materials comprising the absorbent core of the absorbent article need to have sufficient wettability and swelling to facilitate intake of the fluid. 25 However, conventional absorbent cores comprise a mixture of hot-melt adhesives and superabsorbent particles that have surface properties that prevent rapid intake of fluid. In fact, portions of the matrix of hot-melt adhesives and superabsorbent particles that comprise the core are hydrophobic and cause fluid to flow to other regions of the absorbent core for absorption and slow down fluid intake. This can lead to passage of fluid out of the absorbent article and onto the 30 user’s skin during an initial insult. Accordingly, these absorbent articles tend to have slow fluid intake and more leakage. 1 US2008232505803 K‐C Confidential PATENT Attorney Docket No.: 109296-1425315

[0004] There remains a need for an absorbent core that can adequately improve the fluid intake time to prevent the incidence of leakage of fluid from the absorbent article while keeping the skin sufficiently dry. SUMMARY

[0005] Covered embodiments of the present disclosure are defined by the claims, not this summary. This summary is a high-level overview of various aspects of the invention and introduces some of the concepts that are further described in the Detailed Description section below. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used in isolation to determine the scope of the claimed subject matter. The subject matter should be understood by reference to appropriate portions of the entire specification, any or all drawings and each claim.

[0006] In some embodiments, the present disclosure provides a composite comprising: a mixture of superabsorbent particles and an adhesive, wherein the adhesive is dispersed throughout the superabsorbent particles; and an ionization chemistry or additive disposed on the adhesive; wherein the composite has a total surface energy greater than 122 mj / m2at 1 % fractional surface coverage; wherein the ionization chemistry or additive disposed on the adhesive increases an ionization level of the superabsorbent particles by at least 1 %. In some embodiments, the composite comprises less than 6 wt. % of adhesive based on the total weight of the superabsorbent particles. In some embodiments, the ionization chemistry or additive disposed on the adhesive comprises from 0.10 to 5.0 wt. %, based on the total weight of the adhesive. In some embodiments, a bulk contact angle of the adhesive ranges from 50° to 80°. In some embodiments, the adhesive comprises one or more of inorganic hydroxides, carbonates, bicarbonates, oxides, and phosphate salts, organic hydroxides, quaternary ammonium salts, amino acids, amino acids-related salts, polymeric amines, polymeric imines, polycarbonates, polymeric phosphate salts, polyacrylic acids sodium salts, and polymeric quaternary ammonium salts. In some embodiments, the composite comprises a total surface energy from 122 mj / m2to 160 mj / m2at 1 % fractional surface coverage. In some embodiments, the superabsorbent particles comprise an average particle size ranging from about 150 microns to 850 microns. In some embodiments, the adhesive comprises a storage modulus strength ranging from 0.5 x 10^4 Pa to 10.0 x 10^4 Pa at temperature range of 25 °C to 37 °C. In some embodiments, the adhesive 2 US2008232505803PATENT Attorney Docket No.: 109296-1425315 comprises a storage modulus strength ranging from 1.0 x 10^4 Pa to 10.0 x 10^4 Pa at temperature range of 25 °C to 37 °C. In some embodiments, the composite has a polar surface energy ranging from 8 mj / m2to 18 mj / m2at 1 % fractional surface coverage. In some embodiments, the superabsorbent particles comprise an initial neutralization level of at least 70%.

[0007] In some embodiments, the present disclosure provides an absorbent core comprising: a first substrate material having a first surface and a second surface; a second substrate material having a first surface and a second surface; and a composite disposed between the first substrate and the second substrate, wherein the composite comprises superabsorbent particles, an adhesive, and an ionization chemistry or additive disposed on the adhesive; wherein the composite has a basicity constant (Kb) greater than 0.78 at 1 % fractional surface coverage. In some embodiments, a bulk contact angle of the adhesive ranges from 50° to 80°. In some embodiments, the composite comprises a total surface energy from 122 mj / m2to 160 mj / m2at 1 % fractional surface coverage. In some embodiments, the composite comprises a polar surface energy of at least 10.1 mj / m2at 1 % fractional surface coverage. In some embodiments, the composite is substantially free from fluff. In some embodiments, the superabsorbent particles comprise an initial neutralization level of at least 70%. In some embodiments, the adhesive comprises a storage modulus strength ranging from 0.5 x 10^4 Pa to 10.0 x 10^4 Pa at temperature range of 25 °C to 37 °C.

[0008] In some embodiments, the present disclosure provides a method of producing a composite, the method comprising: providing superabsorbent particles; providing an adhesive; depositing the superabsorbent particles on a substrate; and spraying the adhesive on the superabsorbent particles while the superabsorbent particles are being deposited on the substrate to produce a composite; wherein the composite has a polar surface energy greater than 10.1 mj / m2at 1 % fractional surface coverage. In some embodiments, the adhesive sprayed onto the superabsorbent particles is a rubber-based adhesive. In some embodiments, the method further comprises aging the composite deposited on the substrate at a temperature less than 55 °C for a period up to two weeks. In some embodiments, the method further comprises depositing the superabsorbent particles comprises: supplying the superabsorbent particles to a chute; and metering an amount of superabsorbent particles falling from the chute onto the substrate. In some 3 US2008232505803PATENT Attorney Docket No.: 109296-1425315 embodiments, the adhesive is sprayed onto the superabsorbent particles as the superabsorbent particles are falling from the chute to the substrate.

[0009] In some embodiments, the present disclosure provides a composite comprising: a mixture of superabsorbent particles and an adhesive, wherein the adhesive is dispersed throughout the superabsorbent particles; wherein the composite has a basicity constant (Kb) greater than 0.78 at 1 % fractional surface coverage.

[0010] In some embodiments, the present disclosure provides a composite comprising: a mixture of superabsorbent particles and an adhesive, wherein the adhesive is dispersed throughout the superabsorbent particles; wherein the composite has a polar surface energy greater than 10.1 mj / m2at 1 % fractional surface coverage.

[0011] The present disclosure is also directed to an improved absorbent article incorporating the absorbent composite. Further, the present disclosure is directed to methods of manufacturing the absorbent composite or the absorbent article in which the absorbent composite is employed.

[0012] Further aspects, objects, and advantages will become apparent upon consideration of the detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] FIG.1 is a graph of the total surface energy (mj / m2) in relation to surface coverage for exemplary composites.

[0014] FIG.2 is a graph of the polar surface energy (mj / m2) in relation to surface coverage for exemplary composites.

[0015] FIG.3 is a graph of the basicity constant (Kb) in relation to surface coverage for exemplary composites.

[0016] FIG.4 is a graph of the total surface energy (mj / m2) in relation to surface coverage for exemplary composites.

[0017] FIG.5 is a graph of the polar surface energy (mj / m2) in relation to surface coverage for exemplary composites.

[0018] FIG.6 is a graph of the basicity constant (Kb) in relation to surface coverage for exemplary composites. 4 US2008232505803PATENT Attorney Docket No.: 109296-1425315

[0019] FIG.7 is a flowchart of a method for producing a composite according to some embodiments of the present invention. DETAILED DESCRIPTION Introduction

[0020] The present disclosure relates to a composite and an absorbent core including a composite that facilitates initial surface wetting and rapid intake of fluid. The composite described herein includes a mixture of superabsorbent particles and adhesives having specific properties that provide hydrophilic properties on the surface area of the composite. In particular, the composite includes an adhesive modified with ionization chemistries or additives that neutralize the superabsorbent particles. The modified adhesive unexpectedly neutralizes the superabsorbent particles such that the neutralization ratio of the superabsorbent particles is increased by at least 1 %. The higher neutralization level of the superabsorbent particles beneficially provides a composite having a basicity constant and surface properties (e.g., polar surface energy and total surface energy) that have a synergistic effect of improving both initial surface wetting and osmotic swelling of the superabsorbent particles for rapid fluid intake. For example, the composite including the superabsorbent particles and modified adhesive has a total surface energy greater than 122 mj / m2at 1 % fractional surface coverage, a basicity constant greater than 0.75 at 1 % fractional surface coverage, and / or a polar surface energy greater than 10.1 mj / m2at 1 % fractional surface coverage. The surface coverage is the measure of the portion of the composite (% of the surface area of the material) that has a particular property. The fluid intake time of a composite is improved by controlling the surface hydrophilicity, surface energy, and / or basicity constant of the composite to promote ionization of the superabsorbent particles.

[0021] Conventional absorbent cores may include a network of superabsorbent particles and hot-melt adhesives. The hot-melt adhesives are sprayed onto the superabsorbent particles to fix the particles in a location and to keep the superabsorbent particles together. However, the hot- melt adhesives form a hydrophobic film at sites around the superabsorbent particles which prevents rapid absorption of fluid in response to an insult. For example, the hot-melt adhesives may include lower molecular-weight mineral oils that can migrate from adhesive to the surface of the superabsorbent particle during processing which can dramatically reduce the liquid intake 5 US2008232505803PATENT Attorney Docket No.: 109296-1339857 time. In essence, the hot-melt adhesives may prevent fluids from directly contacting the superabsorbent particles. Therefore, fluid needs to flow to a void in the core without adhesive which results in stagnation of the fluid until the fluid makes contact with the superabsorbent particles. This creates a slow intake problem which can lead to leakage or discomfort for a person wearing an absorbent article including the absorbent core.

[0022] The composite described herein avoids the conventional problem of slow fluid intake and facilitates rapid intake of fluid into, for example, an absorbent core including the composite. The superabsorbent particles and adhesive have specific properties that result in a composite having a total surface energy, polar surface energy, and / or basicity constant that contribute to the hydrophilicity of the composite. It was unexpectedly found that the surface and structural features of the composite can be controlled by using specific superabsorbent particles and a modified adhesive to improve the ability of the surface of the composite to be hydrated quickly upon insult. Additionally, the composite can generate high osmotic pressure for faster swelling after initial surface wetting due to the composite’s total surface energy, polar surface energy, basicity constant, or combination thereof. The composite’s total surface energy, polar surface energy, basicity constant, or combination thereof leads to higher surface neutralization of the superabsorbent particles, and thus higher osmotic pressures are generated in response to an insult (e.g., fluid including 0.9 wt. % saline or urine). Additionally, the composite can limit or stop the migration of the mineral oils—typically found in adhesives—from migrating to the surface of superabsorbent particles.

[0023] Beneficially, the composite allows for rapid intake of fluid and prevents fluid from flowing back out of the composite. The composite has finely tuned surface and structural properties for improving liquid intake times. In particular, the surface hydrophilicity of the composite improves hydration speed of the composite and the ionization levels for osmotic swelling after initial wetting provides rapid intake of fluid (e.g., less than 1 minute). The ability of the composite to rapidly hydrate the surface of the composite when contacted by fluids allows the fluid to contact the superabsorbent particles. Definitions and Descriptions:

[0024] The terms “invention,” “the invention,” “this invention,” and “the present invention” used herein are intended to refer broadly to all of the subject matter of this patent application and 6 US2008232505803PATENT Attorney Docket No.: 109296-1339857 the claims below. Statements containing these terms should be understood not to limit the subject matter described herein or to limit the meaning or scope of the patent claims below.

[0025] As used herein, the meaning of “a,” “an,” or “the” includes singular and plural references unless the context clearly dictates otherwise.

[0026] As used herein, an “absorbent article” refers to an article which may 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. It is to be understood that the present disclosure is applicable to various disposable absorbent articles, including, but 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 and other adult care garments, medical garments, surgical pads and bandages, other personal care or health care garments, and the like without departing from the scope of the present disclosure.

[0027] As used herein, the term “hydrophilic” refers to components which are wetted by aqueous liquids in contact with the components (e.g., the adhesive or composite). The degree of wetting of the materials can, in turn, be described in terms of the contact angles and the surface tensions of the liquids and materials involved. Equipment and techniques suitable for measuring the wettability of particular materials can be provided by Cahn SFA-222 Surface Force Analyzer System, or a substantially equivalent system. When measured with this system, adhesives or composites having contact angles less than 90⁰ are designated “wettable” or hydrophilic, and adhesives or composites having contact angles greater than 90⁰ are designated “nonwettable” or hydrophobic.

[0028] As used herein, the term “bonded” refers to the joining, adhering, connecting, attaching, or the like, of two elements. Two elements will be considered bonded together when they are joined, adhered, connected, attached, or the like, directly to one another or indirectly to one another, such as when each is directly bonded to intermediate elements. The bonding of one element to another can occur via continuous or intermittent bonds.

[0029] As used herein, the term “superabsorbent” refers herein to a water-swellable, water- insoluble organic or inorganic material capable, under the most favorable conditions, of absorbing at least about 15 times its weight and, in some embodiments, at least about 30 times its weight, in an aqueous solution containing 0.9 weight percent sodium chloride. The 7 US2008232505803PATENT Attorney Docket No.: 109296-1339857 superabsorbent materials can be natural, synthetic, and modified natural polymers and materials. In addition, the superabsorbent materials can be inorganic materials, such as silica gels, or organic compounds, such as cross-linked polymers.

[0030] All ranges disclosed herein are to be understood to encompass any and all subranges subsumed therein. For example, a stated range of “1 to 10” should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1 or more, e.g., 1 to 6.1, and ending with a maximum value of 10 or less, e.g., 5.5 to 10. Composite

[0031] The composite comprises a mixture of superabsorbent particles and adhesive. The composite can be formed by combining superabsorbent particles and adhesive without dissolving or blending the materials into each other. For example, the composite may include an adhesive dispersed throughout the superabsorbent particles, and the superabsorbent particles can be immobilized by contact with the adhesive. The specific properties of the superabsorbent particles and adhesive are tailored to provide a composite having a combination of surface hydrophilicity and osmotic swelling properties for rapid fluid intake. For example, the composite may have a combination of total surface energy, polar surface energy, and / or basicity that allows for rapid surface hydration and osmotic swelling for rapid fluid intake speeds. The fluid intake time may be defined by the time elapsed for the composite to fully absorb the liquid insult (e.g., disappearance of fluid after the insult). In some embodiments, the composite may have a fluid intake time less than one minute in response to a liquid insult (e.g., less than 45 seconds, less than 30 seconds, less than 20 seconds, or less than 10 seconds).

[0032] Beneficially, the composite achieves rapid fluid intake by selecting suitable superabsorbent particles and adhesives that facilitate fast initial surface wetting upon liquid insults (e.g., during the first few seconds of surface wetting), facilitate rapid osmotic pressure swelling after initial surface wetting, and provide anchoring points for fixing discrete superabsorbent particles into fibrous or stranded adhesive networks that allow fast liquid access, penetration, absorption, and redistribution. The adhesives described herein facilitate fast initial surface wetting and osmotic swelling. In some instances, the osmotic swelling is a more dominant force for liquid intake after initial surface wetting. 8 US2008232505803PATENT Attorney Docket No.: 109296-1339857

[0033] To facilitate the initial fast surface wetting / liquid intake, a suitable adhesive for producing the composite has a bulk contact angle (or water contact angle measured by Sessile drop method) of less than 90°. The bulk contact angle provides an indication of how well or poorly a liquid will spread over a surface. The lower the bulk contact angle for the adhesive, the better surface wettability is expected for the composite as an adhesive having a bulk contact angle (or water contact angle) less than 90° promotes wettability (e.g., ability of a fluid to spread or adhere to a surface) of the composite. If the bulk contact angle of the adhesive is 90° or greater, liquid that contacts the adhesive will stay on the surface of the composite and lead to poor intake time. In some embodiments, the adhesive used in the composite described herein can have a bulk contact angle less than 90° (e.g., less than 85°, less than 80°, less than 75°, less than 70°, less than 65°, or less than 60°). In some embodiments, the adhesive can have a bulk contact angle that ranges from 20° to less than 90° (e.g., from 20° to 80°, from 30° to 70°, from 40° to 60°, from 60° to 80°, from 65° to 85°, from 70° to 80°, from 50° to 70°, or from 60° to 70°).

[0034] To enhance liquid intake after initial surface wetting, the adhesive has a combination of surface and bulk properties that enhances ionization levels of superabsorbent particles so that higher osmotic swelling can be realized. The ionization levels of superabsorbent particles refer to the amount of sodium ions that will dissociate from the superabsorbent particles and become independent free particles. For example, for superabsorbent particles comprising polyacrylate- based polymers, the ionization level can be the amount of sodium ions that will dissociate from the superabsorbent particles and become independent free particles from polyacrylate units in the polymer chain of the superabsorbent particles upon liquid insult. It was unexpectedly found that that higher ionization levels provide for faster liquid intake as the osmotic swelling is directly proportional to the total particle concentrations in the composite.

[0035] Additionally, the ionization levels of polyacrylate-based superabsorbent particles are relatively low (e.g., about 4 – 7 % ionization) in electrolyte solutions with salt concentrations similar to human urine (e.g., ~ 0.9% NaCl saline). Therefore, any small amount of ionization level enhancement can lead to significantly more osmotic swelling of the composite. For example, a 2 % ionization-level enhancement of the superabsorbent particles can potentially lead to about 29 % more osmotic swelling if the initial ionization level is at about 7 %. In this regard, the adhesives suitable for enhanced osmotic swelling include chemistries or additives for helping 9 US2008232505803PATENT Attorney Docket No.: 109296-1339857 to achieve faster liquid intake times. In some embodiments, the ionization chemistries or additives enhance the neutralization levels of the superabsorbent particles. For example, the adhesive includes ionization chemistries or additives that alter the neutralization levels of polyacrylate-based superabsorbent particles. For polyacrylate-based superabsorbent particles, the neutralization levels refer to the ratios of the salt form of acrylic acid to the acrylic acid units. In some embodiments, the ratios of the salt form of acrylic acid to the acrylic acid units are in the ranges of, for example, 70% to 30%, 80% to 20%, 90% to 10 %, or 95% to 5%, where the salt form of acrylic acid is neutralized while the acid form of acrylic acid units are un-neutralized. The neutralized salt form of acrylic acid sodium salt is primarily responsible for osmotic swelling as the un-neutralized acid form has very limited dissociation of protons to materially impact the total particle concentration in the composite. For a given or selected superabsorbent material with a fixed neutralization level, for example, with the ratio of 80% to 20%, the adhesive described herein converts some of the un-neutralized acid units to neutralized salt forms, for example, from an initial ratio of 80% to 20% to a ratio of 85% to 15% or 90% to 10% or 95% to 5%. It should be noted here that the extent of the neutralization enhancement can theoretically reach 100%, however, excessive neutralization can lead to a weaker swollen composite.

[0036] In some embodiments, faster intake speed of the composite can be achieved through ionization enhancement for increased charge-charge repulsion induced swelling by adding desired chemistries or additives to the adhesive. As described above, the neutralization enhancement can also increase charge-charge repulsion along the polymer chain of the superabsorbent as the negative charge density will be increased when more acid units of acrylic acid are converted to the salt form of acrylic acid sodium units. In addition to direct charge- charge repulsion from direct neutralization enhancement, the negative charge densities along the superabsorbent polymer chains can be enhanced by pulling away the counter sodium ions from the already neutralized salt of acrylic acid sodium salt units. In this regard, chemistries or additives are added to suitable adhesives to form complexes with sodium ions along the polymer chains of the superabsorbent so that negative charge densities can be enhanced while the pulled- away counter sodium ions along the chain can be considered as fully ionized particles for enhanced osmotic swelling. 10 US2008232505803PATENT Attorney Docket No.: 109296-1339857

[0037] Suitable adhesives can include, but not limited to, one or more ionization enhancement chemistries or additives as described above. For example, the ionization enhancement chemistries or additives can be basic in nature, e.g., they are strong enough bases that can effectively convert un-neutralized acid units in superabsorbent particles. The term “basic in nature” refers to either Brønsted acid-base theory (e.g., acids and bases acting as proton donors and acceptors) or more broadly by Lewis-acid principle (e.g., a Lewis Acid: a species that accepts an electron pair and a Lewis Base: a species that donates an electron pair). More specifically, some of these basic chemistries or additives can be water soluble and provide pH values of above 7 or in some cases above 8, and in some further cases above 9, as long as they can be included in the composite without causing skin contact upon liquid insults. Additionally, some of the chemistries or additives can be selected as a single component chemical agent, such as sodium hydroxide, or in some cases as a combination of multiple components. For example, a multi-component pH buffer mixture (e.g., phosphate buffers, carbonate buffers, or citric acid buffers) with pH values above 7 can be suitable for the composite. Suitable ionization chemistries or additives may be water insoluble, but are capable of neutralizing acidic units of, for example, acrylic acids, or can be configured to migrate to the counter sodium ions on the polymer chains of the superabsorbent particles. Examples of such chemistries or additives can include certain basic in nature but not water-soluble compositions such as metal oxides, various clays, or mineral compositions with pH ranges from 7-9 or higher in water.

[0038] In addition to chemistries and additives that are traditionally inorganic-based, certain organic-based chemistries or additives can also be suitable for being included in the adhesives for ionization enhancement. Such organic-based chemistries or additives may include but are not limited to certain organic hydroxides (e.g., tetra-alkyl hydroxides or the like), quaternary ammonium salts, various amino acids (e.g., arginine or the like), amino acid-related salts (e.g., glycine sodium salt or the like), polymeric amines, polymeric imines, polycarbonates, polymeric phosphate salts, polyacrylic acids sodium salts, polymeric quaternary ammonium salts, and other related organic and polymeric materials with similar properties.

[0039] The adhesive may include ionization chemistries or additives in an amount up to 5 wt. %, based on the total weight of the adhesive, e.g., up to 4.5 wt. %, up to 4.0 wt. %, up to 3.5 wt. %, up to 3.0 wt. %, up to 2.5 wt. %, up to 2.0 wt. %, up to 1.5 wt. %, up to 1.0 wt. %, or up to 0.5 11 US2008232505803PATENT Attorney Docket No.: 109296-1339857 wt. %. In some embodiments, the adhesive may include ionization chemistries or additives in an amount from 0.10 wt. % to 5.0 wt. %, e.g., 0.20 wt. % to 4.5 wt. %, 0.25 wt. % to 4.0 wt. %, 0.50 wt. % to 3.5 wt. %, 1.0 wt. % to 3.0 wt. %, 0.10 wt. % to 1.0 wt. %, 0.10 wt. % to 0.75 wt. %, or 0.10 wt. % to 0.50 wt. %, based on the total weight of the adhesive. In some embodiments, the adhesive may include ionization chemistries or additives in an amount from 0.10 wt. % to 0.50 wt. %, based on the total weight of the adhesive. The chemistries or additives can be added to the adhesive such that that they are exposed on the interfaces between adhesive and superabsorbent particles for faster initial surface wetting and subsequent osmotic swelling.

[0040] Additionally, the surface heterogeneity of the composite can influence the initial surface wetting and subsequent osmotic swelling. The heterogeneity of the surface refers to portions of the composite surface that have different surface properties. For example, portions of the composite surface are easier for liquid access than others, portions of the composite surface are more hydrophilic with higher surface energy than others, and portions of the composite surface are more basic than others, and portions of the composite surface that are more porous than others. In some embodiments, the surface heterogeneity can be fine-tuned and managed by selecting suitable adhesives that hold the superabsorbent particles together. The portions of the surface of the composite that have higher surface energies (e.g., total surface energy and polar surface energy) and higher basicity surface are critical for fast initial surface wetting and subsequent osmotic swelling even if it is a small percentage of the total surface area of the composite (e.g., less than 10%, or, 5%, or 3%, or 1%, etc.).

[0041] The surface heterogeneity can be measured using Inverse Gas Chromatography (iGC). For example, iGC can be used to quantify the surface heterogeneity in terms of total surface energy, polar surface energy, dispersive surface energy, and basicity. The iGC method is a gas- solid technique for characterizing surface and bulk properties of powders, particulates, fibers, films, and semi-solids. A series of organic solvent vapor pulses (hydrophobic probes such as octane, heptane, hexane, and polar probes such as dichloromethane and ethyl acetate) are injected through a column packed with the sample of interest (e.g., the composite comprising a mixture of superabsorbent particles and adhesive). Because iGC is capable of generating accurate solvent pulse sizes across a large concentration range, resulting in isotherms (e.g., amount of probe molecules adsorbed under a desired temperature) at high and low sample 12 US2008232505803PATENT Attorney Docket No.: 109296-1339857 surface coverages, it allows for the accurate determination of heterogeneous surface-energy distributions. For a given fractional surface coverage, a series of concentrations of dispersive and polar probe vapors are injected in a column at a corresponding surface coverage (n / nm, where n is the amount of dispersive and polar probe vapors to cover the desired fractional surface area, and nm is the amount to saturate the same area, with the units for n and nm in moles), and the dispersive surface energy and specific free energy at that particular surface coverage can be determined. Consequently, the injections of probe vapor at different surface coverages will result in a distribution of surface energy as a function of Surface Energetic Heterogeneity. The particular iGC system used for quantifying composite surface properties described herein was the IGC-SEA Surface Energy Analyzer system made by Surface Measurement Systems, LTD, NA., and the column temperature and relative humidity used for the measurements are at 30 ⁰C and at 0% RH, respectively.

[0042] The composite described herein advantageously combines the benefits of fast initial surface wetting and adhesive-enhanced osmotic swelling. It was found that superabsorbent- adhesive composites with higher basicity constants can lead to significantly lower intake times. It is contemplated that lower bulk contact angle of the adhesive (e.g., more hydrophilic adhesive) is not enough for ensuring faster intake time. In this respect, an adhesive that can increase surface (as well as overall particle) neutralization of the superabsorbent particles improves intake of fluid. For example, if the superabsorbent particles has a starting point of neutralization level of 70%, the modified adhesives described herein enhances neutralization levels to at least above 70%, e.g., at least 71 %, at least 72 %, at least 73 %, at least 74 %, at least 75 %, at least 76 %, at least 77 %, at least 78 %, at least 79 %, or at least 80 %, or so on. In some embodiments, the total neutralization level of superabsorbent particles after adhesive-induced neutralization enhancement, particularly on the particle surfaces, may range from 70 % to 95 %, e.g., from 75 % to 95 %, from 70 % to 80 %, from 75 % to 85 %, from 80 % to 95 %, from 80 % to 90 %, from 85 % to 95 %, or anywhere between these ranges.

[0043] Advantageously, the higher osmotic pressure after initial surface hydration (wetting) provides for faster liquid intake. Initially, the hydrophilic properties of the composite are provided, in part, by the adhesive having a bulk contact angle less than 90°, promoting surface wetting. After the initial insult, the composite’s total surface energy, polar surface energy, 13 US2008232505803PATENT Attorney Docket No.: 109296-1339857 basicity, or combination thereof provides high osmotic pressure for fast absorption of the fluid. The high osmotic pressure is more important after initial surface hydration (or wetting) for faster liquid intake and thus shortening the intake time. In some embodiments, the ionization enhancement of the composite occurs as soon as the adhesive contacts the superabsorbent particles. In some embodiments, the ionization enhancement occurs during processing of the composite or upon insult (e.g., contact with urine). In some cases, the ionization chemistries or additives can be dissolved into urine and thus allow more broad interactions of superabsorbent particle surfaces that are not blocked or covered by adhesives. In some embodiments, the ionization enhancement additives are disposed in the interior of the composite.

[0044] According to surface energy models, the surface tension of any fluid or the surface energy of a surface can be represented in air as being primarily composed of dispersive and polar components according to the relationship of equation (i): γ=γd+γp=α2+β2(i) where γ is the total surface The total surface energy is composed of twoorthogonal components, the dispersive component γd and polar component γp, which act to a large degree independently. The polar and dispersive components of surface tension for a liquid or surface energy for a solid can be calculated from tensionmeter or contact angle measurements known in the art using commercial scientific equipment provided by several equipment companies including, for example, First Ten Angstroms, Inc located in Portsmouth, Va., Diversified Enterprises located in Claremont, N.H., or Biolin Scientific Inc. located in Linthicum Heights, Md. Alpha and beta of equation (i) are further defined according to equations (ii) and (iii): α=√{square root over (γd)} (ii); β=√{square root over (γp)} (iii). Alpha and beta are useful in describing molecular surface interactions acting across molecular distances.

[0045] In some embodiments, the composite has a total surface energy ranging from 122 mj / m2to 160 mj / m2at a fractional surface coverage of 1 % as measured according to inverse gas chromatography. For example, the total surface energy ranges 122 mj / m2to 144 mj / m2, from 133 mj / m2to 144 mj / m2, from 125 mj / m2to 160 mj / m2, from 130 mj / m2to 155 mj / m2, from 130 14 US2008232505803PATENT Attorney Docket No.: 109296-1339857 mj / m2to 150 mj / m2, or from 140 mj / m2to 160 mj / m2. In some embodiments, the total surface energy is at least 120 mj / m2, e.g., at least 122 mj / m2, at least 125 mj / m2, at least 130 mj / m2, at least 135 mj / m2, or at least 140 mj / m2at a fractional surface coverage of 1 %.

[0046] In some embodiments, the composite has a polar surface energy ranging from 8 mj / m2to 20 mj / m2at a fractional surface coverage of 1 % as measured according to inverse gas chromatography. For example, the polar surface energy of the composite ranges from 8 mj / m2to 18 mj / m2, from 9 mj / m2to 18 mj / m2, from 10 mj / m2to 18 mj / m2, from 10.1 mj / m2to 13.4 mj / m2, rom 11.8 mj / m2to 13.4 mj / m2, or from 11 mj / m2to 15 mj / m2. In some embodiments, the polar surface energy of the composite is at least 8 mj / m2, e.g., at least 9 mj / m2, at least 10 mj / m2, at least 11 mj / m2, or at least 12 mj / m2at a fractional surface coverage of 1 %.

[0047] The composite has finely tuned surface and structural properties for improving liquid intake times. In particular, the surface hydrophilicity of the composite improves hydration speed, and the ionization levels for osmotic swelling after initial wetting provide rapid intake of fluid (e.g., less than 1 minute). It was found that the strength of the basicity of the composite potentially affects the liquid absorption rate of the composite. Generally, a composite having a high basicity constant exhibits a relatively faster liquid absorption rate. The base strength (pKb) of the composite as used herein refers to the pKb at a water temperature of 25° C, which is one of the indices for quantitatively representing the strength of a base and has the same meaning as the basicity constant.

[0048] The polar components of the surface energy can be used to quantify the acidic portion and basic portion of the surface to determine the basicity of the composite. The superabsorbent particles and adhesive described herein neutralize the acidic portion of the composite for high osmotic swelling when contacted by a fluid. In some embodiments, the composite has a basicity constant of greater than 0.75 at 1 % surface coverage as measured by inverse gas chromatography, e.g., greater than 0.80, greater than 0.82, greater than 0.84, greater than 0.86, greater than 0.88, or greater than 0.90. In some embodiments, the composite has a basicity constant ranging from 0.78 to 1.10, e.g., from 0.78 to 0.93, from 0.87 to 0.93, from 0.80 to 1.10, from 0.82 to 1.06, from 0.84 to 1.05, from 0.85 to 1.10, or from 0.88 to 1.00, at a surface coverage of 1 %. 15 US2008232505803PATENT Attorney Docket No.: 109296-1339857

[0049] The composite described herein can include high energy sites across a wide range of surface coverages, lending to the advantageous properties of fast initial swelling and rapid intake of an insulting fluid. For example, the composite may have the total surface energy, polar surface energy, and basicity values described herein at 1 % fractional surface coverage, 2 % fractional surface coverage, 3 % fractional surface coverage, 4 % fractional surface coverage, or 5 % fractional surface coverage.

[0050] In some embodiments, the composite has a total surface energy from 122 mj / m2to 144 mj / m2at 1 % surface coverage, a polar surface energy from 10.1 mj / m2to 13.4 mj / m2at 1 % surface coverage, and a basicity constant from 0.78 to 0.93 at 1 % surface coverage.

[0051] In some embodiments, the composite has a total surface energy from 133 mj / m2to 144 mj / m2at 1 % surface coverage, a polar surface energy from 11.8 mj / m2to 13.4 mj / m2at 1 % surface coverage, and a basicity constant from 0.87 to 0.93 at 1 % surface coverage.

[0052] In some embodiments, the composite has a total surface energy from 125 mj / m2to 160 mj / m2at 1 % surface coverage, a polar surface energy from 11 mj / m2to 20 mj / m2at 1 % surface coverage, and a basicity constant from 0.80 to 1.10 at 1 % surface coverage. Superabsorbent Particles

[0053] The composite includes one or more superabsorbent particles. In some embodiments, the superabsorbent materials can be selected from natural, synthetic, and modified natural polymers and materials. The superabsorbent materials can be inorganic materials, such as silica gels, or organic compounds, such as cross-linked polymers. The superabsorbent particles have specific properties that contribute to initial surface wetting and osmotic swelling for rapid intake times. For example, the superabsorbent material comprises an absorbent polymer having a vortex time that promotes surface hydration. In some embodiments, the vortex time of the superabsorbent particles is 30 seconds or less (e.g., 25 seconds or less, 20 seconds or less, 15 seconds or less, 10 seconds or less, 5 seconds or less, or 1 second or less).

[0054] In some embodiments, the particle sizes of the superabsorbent material can impact the osmotic swelling of the composite in response to an insult. Determining the particle size of different portions of particles of the bulk superabsorbent material may be performed by any classification process known in the art. For example, it is well known to utilize multiple sieves 16 US2008232505803PATENT Attorney Docket No.: 109296-1339857 with differing mesh sizes to separate out different portions of particles from the bulk superabsorbent material having differing particle size diameters. One particular method which can be used in such a classification effort may be ASTM D1921-18, titled “Standard Test Methods for Particle Size (Sieve Analysis) of Plastic Materials”. In some embodiments, the average superabsorbent particle size is from 150 µm to 850 µm (e.g., from 175 µm to 800 µm, from 200 µm to 750 µm, from 250 µm to 750 µm, from 300 µm to 700 µm, or from 400 µm to 700 µm).

[0055] The superabsorbent materials can include any absorbent polymers, such as (1) the anionic polymers, such as the alkali metal and ammonium salts of poly(acrylic acid), poly(methacrylic acid), isobutylene-maleic anhydride copolymers, poly(vinyl acetic acid), poly(vinyl phosphonic acid), poly(vinyl sulfonic acid), carboxymethyl cellulose, carboxymethyl starch, carrageenan, alginic acid, polyaspartic acid, polyglutamic acid, and combinations and copolymers thereof, (2) the cationic polymers, such as salts of poly(vinyl amine), poly(ethylene imine), poly(amino propanol vinyl ether), poly(allyl amine), poly(quaternary ammonium), poly(diallyl dimethyl ammonium hydroxide), polyasparagins, polyglutamines, polylysines, polyarginines, and combinations and copolymers thereof, (3) the mixture of anionic and cationic superabsorbent polymers, such as any combination of at least each one from Groups (1) and (2); (4) the mixture of acidic and basic polymers, such as acidic polymers from non-neutralized anionic superabsorbent polymers of Group (1) and basic polymers from non-neutralized cationic superabsorbent polymers of Group (2). In one embodiment of this invention the absorbent polymer includes one of sodium polyacrylate, polyvinyl amine salt, polyacrylic acid, polyvinyl amine, and combinations and derivatives thereof.

[0056] The superabsorbent particles may be present in the composite in an amount from 50 wt. % to 95 wt. %, based on the total weight of the composite, e.g., from 50 wt. % to 85 wt. %, from 60 wt. % to 80 wt. %, from 70 wt. % to 90 wt. %, from 80 wt. % to 95 wt. %, or from 75 wt. % to 98 wt. %. In some embodiments, the composite includes at least 50 wt. % superabsorbent particles, e.g., at least 55 wt. %, at least 60 wt. %, at least 65 wt. %, at least 70 wt. %, or at least 75 wt. %.

[0057] In addition to those noted above, other components may also be employed to form the superabsorbent particles. Still other suitable additives that may be employed include light 17 US2008232505803PATENT Attorney Docket No.: 109296-1339857 stabilizers (e.g., hindered amines), chain terminators, slip agents and mold release agents (e.g., fatty acid esters, the metal soaps thereof, fatty acid amides, fatty acid ester amides and silicone compounds), plasticizers, antiblocking agents, inhibitors, stabilizers against hydrolysis, heat and discoloration, dyes, pigments, inorganic and / or organic fillers, fungistatically and bacteriostatically active substances, fillers, etc.

[0058] Other physical properties of the superabsorbent particles may influence the ability and extent of fluid intake described herein. For example, the tensile strength and tensile modulus of the superabsorbent particles are important parameters to support robust absorption of the composite. For example, superabsorbent particles having poor tensile strength and low molecular weight may not be able to support robust expansion of the composite. On the other hand, if the tensile modulus is too high, the superabsorbent particles may be too stiff for expansion and the superabsorbent particles may not have sufficient elasticity for expansion.

[0059] In some embodiments, the tensile modulus of the superabsorbent particles can range from 0.5 MPa to 8 MPa at an elongation of 100 % as measured according to ASTM D-412 (2024), e.g., from 0.75 MPa to 7 MPa, from 0.9 MPa to 6 MPa, from 1 MPa to 5.5 MPa, from 1 MPa to 5 MPa, from 1.5 MPa to 4.5 MPa, or from 2 MPa to 4 MPa. In some embodiments, the tensile modulus of the superabsorbent particles can range from 1 MPa to 5 MPa at an elongation of 100 % as measured according to ASTM D-412 (2022).

[0060] In some embodiments, the tensile strength of the superabsorbent particles can range from 5 MPa to 100 MPa, e.g., from 10 MPa to 80 MPa, from 15 MPa to 60 MPa, from 20 MPa to 50 MPa, from 25 MPa to 50 MPa, from 30 MPa to 60 MPa, or from 30 MPa to 50 MPa. In some embodiments, the tensile strength of the superabsorbent particles can range from 20 MPa to 50 MPa. Adhesives

[0061] The composite includes one or more adhesives. The adhesives may be present in the composite in an amount less than 10 wt. %, based on the total weight of the superabsorbent particles. For example, the amount of adhesive may be less than 9 wt. %, less than 8 wt. %, less than 7 wt. %, less than 6 wt. %, less than 5 wt. %, or less than 4 wt. %, based on the total weight of the superabsorbent particles. In other embodiments, the amount of adhesive may range from 2 wt. % to 10 wt. %, from 3 wt. % to 7 wt. %, from 4 wt. % to 7 wt. %, from 5 wt. % to 7 wt. %, or 18 US2008232505803PATENT Attorney Docket No.: 109296-1339857 from 2 wt. % and 5 wt. %. As one illustrative example, where the superabsorbent material is disposed in a composite at a basis weight of 500 gsm, the resulting basis weight of the adhesive in the composite would be 25 gsm (5 wt. % of 500 gsm).

[0062] In some embodiments, the adhesive filament size and particle sizes of the superabsorbent material can impact the osmotic swelling of the composite in response to an insult. The average filament diameter may affect the ability of the superabsorbent material to be bound by the adhesive filaments and can potentially reduce absorptive performance because the adhesive filaments would more readily block liquid from accessing all portions of the individual particles. In some embodiments, the adhesive filaments have average diameters from 25 microns to 150 microns.

[0063] In some embodiments, the adhesive may optionally include one or more additives. In some embodiments, the additives may include surfactants, absorbents, skin benefit agents, plasticizers, minerals, antibiotics, or any combination thereof. The surface of the adhesives can be modified with one or more additives to provide an adhesive with a bulk contact angle of less than 90°. For example, a hydrophilic wetting agent (e.g., a surfactant) can be added to the adhesive. In some embodiments, the adhesive can be co-polymerized with a polar polymer to provide a hydrophilic adhesive. The adhesive can be a styrene-based polymer or polyolefin- based polymer that is co-polymerized with a polymer that is more polar than the styrene-based polymer or polyolefin-based polymer to produce a surface-modified adhesive.

[0064] In some embodiments, the adhesive can include one or more ionization enhancement chemistries or additives as described herein that are basic in nature as defined broadly by either Brønsted acid-base theory (e.g., acids and bases acting as proton donors and acceptors) or more broadly by Lewis-acid principle (e.g., a Lewis Acid: a species that accepts an electron pair and a Lewis Base: a species that donates an electron pair). Suitable such ionization chemistries or additives may include inorganic hydroxides, carbonates, bicarbonates, oxides, and phosphate salts, or other related inorganics with similar properties, organic hydroxides, quaternary ammonium salts, amino acids, amino acids-related salts, polymeric amines, polymeric imines, polycarbonates, polymeric phosphate salts, polyacrylic acids sodium salts, polymeric quaternary ammonium salts, and other related organic and polymeric materials with similar properties. 19 US2008232505803PATENT Attorney Docket No.: 109296-1339857

[0065] The ionization enhancement chemistries or additives for improving adhesive hydrophilicity (e.g., lowering bulk contact angle) and basicity (e.g. enhancing neutralization levels) can be a single chemical agent or a combination with a mixture of different chemical agents or materials. For example, some hydrophilic chemistries or additives might be hydrophilic, but they might not have strong neutralization capabilities. However, such hydrophilic chemistries or additives can provide other properties such as helping texture or strength or thermal processing for forming the composite. Examples of such chemistries or additives include but are not limited to certain polymers like polyalcohols, polyacids, polyethylene glycols (PEGs or PEOs), etc. Ideally, a single chemistry or additive can provide both properties, but this is not necessary as a combination of mixture compositions might be easier to prepare.

[0066] In addition to the components noted above, other additives may also be incorporated, such as slip additives (e.g., fatty acid salts, fatty acid amides, etc.), compatibilizers (e.g., functionalized polyolefins), dispersion aids, melt stabilizers, processing stabilizers, heat stabilizers, light stabilizers, antioxidants, heat aging stabilizers, whitening agents, antiblocking agents, bonding agents, lubricants, fillers, etc.

[0067] In some embodiments, the storage modulus of the adhesive can range from 0.5 x 10^4 Pa to 10.0 x 10^4 Pa at temperature ranges of 25 °C to 37 °C at an elongation of 100 % as measured according to ASTM D-412 (2024). In some embodiments, the storage modulus of the adhesive can range from 1.0 x 10^4 Pa to 7.0 x 10^4 Pa at temperature ranges of 25 °C to 37 °C, e.g., from 1.0 x 10^4 Pa to 5.0 x 10^4 Pa, 1.0 x 10^4 Pa to 4.0 x 10^4 Pa, or anywhere in between.

[0068] The relative amount of the superabsorbent particles and adhesive employed in the composite may also be selected to help further optimize rapid intake of fluid. In some embodiments, the weight ratio of the superabsorbent particles to the adhesive is at least 90:10, e.g., 95:5, 97:3, 98:2, 99:1, 99.5:0.5, or anywhere in between.

[0069] In some embodiments, the adhesive used in the composite described herein can have a bulk contact angle less than 90° (e.g., less than 85°, less than 80°, less than 75°, less than 70°, less than 65°, or less than 60°). In some embodiments, the adhesive can have a bulk contact angle that ranges from 20° to less than 90° (e.g., from 20° to 80°, from 30° to 70°, from 40° to 20 US2008232505803PATENT Attorney Docket No.: 109296-1339857 60°, from 60° to 80°, from 65° to 85°, from 70° to 80°, from 50° to 70°, or from 60° to 70°). Examples of suitable materials include hydrophilic polymers.

[0070] The adhesive may also have sufficient tack and cohesion for wet integrity of the composite. Exemplary suitable adhesives include natural resin-based adhesives or hot-melt adhesives. For example, a suitable exemplary adhesive may contain but is not limited to, a styrenic block copolymer-based hot-melt adhesive designed to have high cohesion and strong specific adhesion to provide good fixation of the superabsorbent material in the absorbent structure under both wet and dry conditions. The adhesives may be non-water soluble to help retain the positioning of the superabsorbent material within the structure after one or more liquid insults. For example, rubber-based adhesives may produce structures which perform superior to other adhesives, such as standard construction adhesives or olefin-based adhesives. Absorbent Core

[0071] An absorbent core may include the composite described herein. In some embodiments, an absorbent core may comprise a first substrate material layer having a first surface and a second surface, a second substrate material layer having a first surface and a second surface, and the composite described herein can be disposed between the first substrate material layer and the second substrate material layer. The composite includes a mixture of superabsorbent particles and adhesive with the superabsorbent particles immobilized by the adhesive. Absorbent cores help with liquid intake and storage within absorbent articles. Many absorbent cores contain multiple absorbent materials such as superabsorbent material or other fibrous absorbent material. Each type of absorbent material helps to impart such absorbent cores with a range of properties useful in absorbing and retaining liquid bodily exudates. For example, fluff pulp or other fibrous absorbent material may absorb liquid quickly, and the superabsorbent material may be able to retain more liquid per gram than fluff pulp. In some embodiments, the absorbent core can be pulp free.

[0072] The absorbent core can be incorporated in an absorbent article. For example, the absorbent core can be used in diapers, training pants, adult incontinence products, bodily exudates absorbing products, feminine hygiene products, and other absorbent products. 21 US2008232505803PATENT Attorney Docket No.: 109296-1339857

[0073] In some embodiments, the absorbent article may be a diaper. In this embodiment, the absorbent core including the composite can be incorporated in a region of the article that receives the insulting fluid. The absorbent article can include a chassis, a front waist region, a rear waist region, and a crotch region disposed between the front waist region and the rear waist region and interconnecting the front and rear waist regions. The front waist region can be referred to as the front-end region, the rear waist region can be referred to as the rear-end region, and the crotch region can be referred to as the intermediate region. In one embodiment, a three-piece construction of an absorbent article is contemplated where the absorbent article can have a chassis including a front waist panel defining the front waist region, a rear waist panel defining the rear waist region, and an absorbent panel defining the crotch region of the absorbent article. The absorbent panel can extend between the front waist panel and the rear waist panel. In some embodiments, the absorbent panel can overlap the front waist panel and the rear waist panel. The absorbent panel can be bonded to the front waist panel and the rear waist panel to define a three- piece construction.

[0074] The front waist region can include the portion of the absorbent article that, when worn, is positioned at least in part on the front of the wearer while the rear waist region can include the portion of the absorbent article that, when worn, is positioned at least in part on the back of the wearer. The crotch region of the absorbent article can include the portion of the absorbent article that, when worn, is positioned between the legs of the wearer and can partially cover the lower torso of the wearer. The waist edges of the absorbent article are configured to encircle the waist of the wearer and together define a central waist opening for the waist of the wearer. Portions of the longitudinal side edges in the crotch region can generally define leg openings for the legs of the wearer when the absorbent article is worn.

[0075] The absorbent article can include an outer cover and a bodyside liner. The outer cover and the bodyside liner can form a portion of the chassis. In an embodiment, the bodyside liner can be bonded to the outer cover in a superposed relation by any suitable means such as, but not limited to, adhesives, ultrasonic bonds, thermal bonds, pressure bonds, or other conventional techniques. The outer cover can define a length in a longitudinal direction, and a width in the lateral direction can coincide with the length and width of the absorbent article. 22 US2008232505803PATENT Attorney Docket No.: 109296-1339857

[0076] The chassis can include an absorbent body including the absorbent core. The absorbent body can be disposed between the outer cover and the bodyside liner. The absorbent body can have longitudinal edges, which, in an embodiment, can form portions of the longitudinal side edges of the absorbent article. In an embodiment, the absorbent body can have a length and width that are the same as or less than the length and width of the absorbent article. The bodyside liner, the outer cover, and the absorbent body can form part of an absorbent assembly. The absorbent assembly can also include a fluid transfer layer and a fluid acquisition layer between the bodyside liner and the fluid transfer layer. The absorbent assembly can also include a spacer layer disposed between the absorbent body and the outer cover.

[0077] The absorbent article can be configured to contain and / or absorb liquid, solid, and semi-solid body exudates discharged from the wearer. In some embodiments, containment flaps can be configured to provide a barrier to the lateral flow of body exudates. To further enhance containment and / or absorption of body exudates, the absorbent article can suitably include a waist containment member. Method of Producing an Absorbent Core

[0078] Absorbent core according to the present disclosure may be formed according to the processes disclosed herein. The absorbent core may advantageously provide greater thinness, flexibility, superabsorbent material capture, and pad integrity than absorbent cores formed by different processes and / or comprising different material or different relative amounts of material.

[0079] FIG.7 provides a flow diagram of a method for producing a composite core according to some embodiments. In some embodiments, a method 700 of producing a composite is provided. The method 700 may include providing superabsorbent particles 710. As described herein, the superabsorbent particles may have the properties described herein (e.g., tensile modulus, vortex time, and particle size). For example, the superabsorbent particles can be a polyacrylic acid-based polymer having a vortex time of 30 seconds or less. In some embodiments, the superabsorbent particles have average particle sizes from 150 microns to 850 microns.

[0080] The method 700 may include providing an adhesive 720. Suitable adhesives include adhesives having a bulk contact angle less than 90° that result in a composite having the total 23 US2008232505803PATENT Attorney Docket No.: 109296-1339857 surface energy and polar surface energy described herein to provide rapid intake of fluid. In some embodiments, the adhesive is a styrenic block copolymer based hot melt adhesive designed to have high cohesion and strong specific adhesion to provide good fixation of the superabsorbent material in the absorbent core under both wet and dry conditions. In some embodiments, the properties of the adhesive can be modified by adding further additives to, for example, improve hydrophilicity of the adhesive. For example, the adhesive may include inorganic hydroxides, carbonates, bicarbonates, oxides, and phosphate salts, or other related inorganics with similar properties, organic hydroxides, quaternary ammonium salts, amino acids, amino acids-related salts, polymeric amines, polymeric imines, polycarbonates, polymeric phosphate salts, polyacrylic acids sodium salts, polymeric quaternary ammonium salts, and other related organic and polymeric materials with similar properties.

[0081] The method 700 may include depositing superabsorbent particles onto a substrate 730. The superabsorbent particles may flow from a hopper and through a chute toward a substrate (e.g., a web material). For example, the superabsorbent particles can be supplied to a chute via a hopper. The amount of superabsorbent particles falling from the chute onto the substrate can be metered to provide a specific amount of superabsorbent particles on a region of the substate.

[0082] The method 700 may include spraying the adhesive on the superabsorbent particles to produce a composite 740. For example, the adhesive applicator may spray adhesive onto superabsorbent material prior to depositing superabsorbent particles onto the substrate 730, for example in a mixing region, and ultimately deposits onto the substrate 730. The adhesive can be heated to an application temperature and then sprayed on the superabsorbent particles to produce the composite. The application temperature of the adhesive to fix the superabsorbent particles in the absorbent core can impact the properties of the composite, and ultimately fluid intake and absorption of fluid. In some embodiments, the adhesive can be heated to an application temperature from 285 °F to 360 °F (e.g., from 285 °F to 355 °F, from 290 °F to 350 °F, from 295 °F to 350 °F, from 300 °F to 350 °F, or from 305 °F to 360 °F). For example, the adhesive can be heated to a temperature of 285 °F, 290 °F, 295 °F, 300 °F, 305 °F, 310 °F, 315 °F, 320 °F, 325 °F, 330 °F, 335 °F, 340 °F, 345 °F, 350 °F, 355 °F, or 360 °F. If the temperature of the adhesive is greater than 360 °F, non-swellable agglomerates may form on the surface of the superabsorbent particles leading to less surface area for fluid intake. If the temperature of the adhesive is less than 285 °F, the adhesive may not sufficiently bond the superabsorbent particles 24 US2008232505803PATENT Attorney Docket No.: 109296-1339857 leading to loose particles in unwanted regions of the absorbent core. The processing temperature of the adhesive can range from 285 °F to 360 °F beneficially provides a balance of fixing the superabsorbent particles in place and limiting the amount of adhesive for covering the superabsorbent particle surface in the composite. In some embodiments, a second substrate is placed on top of the superabsorbent / adhesive composite.

[0083] In some embodiments, the method includes aging the composite. For example, the composite may be naturally aged or artificially aged. As one example, after producing the composite, the composite can be aged at room temperature for a period up to 4 weeks (e.g., up to 3 weeks or up to 2 weeks). In some embodiments, the composite can be heated to a temperature above room temperature and aged for a period up to 4 weeks (e.g., up to 3 weeks or up to 2 weeks). For example, the composite can be aged for up to two weeks at a temperature less than 65 °C (e.g., from 20 °C to 65 °C, from 20 °C to 55 °C, from 40 °C to 60 °C, or from 50 °C to 60 °C). Surprisingly, it was found that aging the composite described herein can limit or stop the migration of the mineral oils typically found in adhesives from migrating to the superabsorbent particle surface. In some embodiments, the composite can be aged for two weeks at a temperature from 50 °C to 60 °C at an average relative humidity less than 10 %.

[0084] An exemplary method of producing an absorbent core including the composite is provided below. The process may include unwinding web material and moving the web material in a direction (e.g., a machine direction). The machine direction may be defined as a direction parallel within the web material and, accordingly, may be perpendicular to a vertical direction. In some exemplary embodiments, an adhesive applicator may apply adhesive to the web material. The adhesive applicator may apply the adhesive to the web material pneumatically or through various coating methods - or any other suitable application method - in the form of dots, beads, swirls, or any other suitable pattern. Although, it should be noted that the adhesive applicator and adhesive may be optional and not present in other embodiments. Accordingly, in such embodiments, adhesive is not placed onto the web material.

[0085] In either case, the web material may continue in the machine direction, arriving at an absorbent material deposition station. At the absorbent material deposition station, superabsorbent material intermixes with one or more adhesives prior to depositing onto the web material, for example in a mixing region, and ultimately deposits onto the web material. In some embodiments, the superabsorbent material flows from hopper and through chute toward the web 25 US2008232505803PATENT Attorney Docket No.: 109296-1339857 material. The hopper may be a bulk solid pump or feeder configured to maintain a consistent flow of the superabsorbent material through the absorbent material deposition station. The flow rate of the superabsorbent material out of the hopper may be adjustable such that the hopper can deliver different amounts of superabsorbent material, resulting in different basis weights of superabsorbent material in the finished absorbent core. Such differences in basis weights of superabsorbent material may allow the formed absorbent core to be used in different absorbent end uses - such as in diapers, feminine articles, adult care garments, bandages and the like.

[0086] The chute may be oriented in a direction (e.g., vertical direction) such that the superabsorbent particles can exit the chute and fall on the web material. The superabsorbent particles may be fed through the absorbent material deposition station by gravity, without any pneumatic force. In some embodiments, the superabsorbent material may fall toward the web material having a direction including a component in both the vertical direction and the machine direction.

[0087] In general, the amount of superabsorbent material fed through the absorbent material deposition station may be configured to result in absorbent core comprising superabsorbent material disposed in amounts between 50 gsm and 1000 gsm, or between 100 gsm and 1000 gsm, or between 150 gsm and 1000 gsm, or between 200 gsm and 800 gsm, or between 250 gsm and 800 gsm, or between 300 gsm and 700 gsm, or between 350 gsm and 700 gsm, or between 400 gsm and 700 gsm, or between 450 gsm and 700 gsm, or between 500 gsm and 700 gsm, or between 400 gsm and 600 gsm, or between 500 gsm and 600 gsm. Such superabsorbent material basis weight values for absorbent core may be particularly suitable for use in absorbent garments and feminine hygiene products. However, absorbent cores produced according to aspects of the present disclosure can have even smaller basis weights of superabsorbent material, such as between 5 gsm and 50 gsm, or 5 gsm and 30 gsm, or between 10 gsm and 30 gsm.

[0088] As the superabsorbent material falls toward the web material, adhesive applicators may spray adhesive toward the falling superabsorbent material. In some embodiments, the adhesive can be heated to a processing temperature prior to being sprayed onto the superabsorbent particles. For example, the adhesive can be heated to an application temperature from 285 °F to 360 °F. The adhesive intermixes with the falling superabsorbent material prior to the mixture of the superabsorbent material and the adhesive depositing onto the web material. The adhesive 26 US2008232505803PATENT Attorney Docket No.: 109296-1339857 applicator may be configured to spray the adhesive such that the adhesive contacts the first side of the stream of superabsorbent material along a portion of the stream having a length along the stream. To allow sufficient time for the adhesive to intermix with the stream of the superabsorbent material prior to the mixture of the first adhesive and the superabsorbent material depositing onto the web material, the adhesive may generally contact the stream at a first contact point located a distance away from the web material. In some embodiments, another adhesive applicator can spray a second adhesive such that the second adhesive contacts the second side of the stream of superabsorbent material along a portion of the stream having a length along the stream. Examples

[0089] Sample composites were tested to investigate the liquid intake time of the composites described herein. Comparative Example 1 and Examples 1 and 2 were prepared according to the methods described below. The composites of Comparative Example 1 and Examples 1 and 2 each comprised 95 wt. % control superabsorbent particles (SAP) commercially available under product code LK601N from LG Chem Ltd. Comparative Example 1 included an adhesive having a bulk contact angle of 110.6°. Examples 1 and 2 included an adhesive modified with ionization chemistries or additives having a bulk contact angle less than 80°. Table 1 provides the composition of the composite and the properties for each of Comparative Example 1 and Examples 1 and 2. TABLE 1 Adhesive Adhesive Wt. % SAP Wt. Total Polar Basicity Bulk Adhesive % Surface Surface Constant Contact SAP Energy Energy @ 0.01 Angle (°) (mj / m2) (mj / m2) surface @ 0.01 @ 0.01 coverage surface surface coverage coverage Comp Henkel 110.6 5 LK601N 95 122 10.1 0.78 Ex.1 5402U Ex.1 Modified 73.5 5 LK601N 95 133 11.8 0.87 Adhesive Ex.2 Modified 76.4 5 LK601N 95 144 13.4 0.93 Adhesive

[0090] As shown in Table 1, Examples 1 and 2 included an adhesive modified with ionization chemistries or additives having a bulk contact angle less than 80° resulting in a composite having 27 US2008232505803PATENT Attorney Docket No.: 109296-1339857 a greater total surface energy, polar surface energy, and basicity constant of the composite compared to Comparative Example 1. As discussed herein, while the lower bulk contact angle may assist with initial surface wetting, the total surface energy, polar surface energy, and basicity constant of the composite, particularly at low surface coverages are critical for initial surface wetting and then subsequent osmotic swelling, i.e., higher surface energy and higher basicity constant leads to greater hydrophilicity and higher ionization levels. For example, Example 2 showed the highest combination of surface energy, polar surface energy, and basicity constant of the composite, properties which have been found to have a synergistic effect of improving surface wetting and osmotic swelling of the superabsorbent for rapid fluid intake. Therefore, the adhesive in combination with the superabsorbent particles can be tailored to improve the fluid intake time of a composite by controlling the surface hydrophilicity, surface energy, and surface basicity constant.

[0091] The fluid intake times for each of Comparative Example 1 and Examples 1 and 2 were tested by simulating the “on-body” position of Personal Care products while measuring liquid handling of multiple simulated loadings. During product usage, rapid liquid intake (or Cradle Intake Time) is important to minimize skin wetness and reduce leakage. The examples were tested in three trials with unaged (T=0) and aged composites. The aged composites were aged at a temperature of 55 °C for 2 weeks. The intake times for each of Comparative Example 1 and Examples 1 and 2 are provided in Table 2 below. In all three trials, Example 2, which had the highest surface energy, polar surface energy, and basicity constant, showed the fastest average fluid intake speed for both the unaged and aged composites across all three insults, other than the unaged sample in the third trial. TABLE 2 Cradle Intake Time (s) 1st(T=0) 1st2nd(T=0) 2nd(Aged) 3rd(T=0) 3rd(Aged) (Aged) Comp Ex.1 37.2 60.1 26.0 41.7 142 257.6 Example 1 25.7 43.7 19.0 27.2 75 132.6 Example 2 23.8 39.5 17.7 18.6 85 110.5

[0092] FIGs.1 and 2 provide graphs of the total surface energy (mj / m2) and polar surface energy (mj / m2) in relation to surface coverage for Comparative Example 1 and Examples 1 and 2, respectively. FIG.3 is a graph of the basicity constant (Kb) in relation to surface coverage for 28 US2008232505803PATENT Attorney Docket No.: 109296-1339857 Comparative Example 1 and Examples 1 and 2. Examples 1 and 2 each exhibited a total surface energy greater than 122 mj / m2at 1 % surface coverage, a polar surface energy of at least 10 mj / m2at 1 % surface coverage, and a basicity constant of at least 0.80 at 1 % surface coverage. Example 2 had the highest total surface energy, polar surface energy, and basicity. As discussed herein, the composite’s basicity constant leads to higher surface neutralization of the superabsorbent particles, and thus higher osmotic pressures are generated in response to an insult. This, and the higher total surface energy and higher polar surface energy, improve the ability of the surface of the composite to be hydrated quickly upon insult, thus resulting in high surface moisture intake speed, and the composite can generate high osmotic pressure for faster swelling after initial surface wetting. In this regard, Example 2 had the lowest intake times across all three trials. In fact, Example 2 had an intake time that was 35 % lower than the intake time of Comparative Example 1 in Trial 1 for the unaged sample. Thus, the chemistries and / or additives added to the adhesive lead to higher total surface energy, higher polar surface energy, higher basicity constants of the composites, which are all consistent with the lower liquid intake times by controlling composite surface properties for faster initial wetting and faster liquid intake induced by osmotic swelling.

[0093] Sample composites were tested to investigate the effect of different adhesives on the liquid intake time of the composites described herein. Comparative Example 2 and Example 3 were prepared according to the methods described herein. Comparative Example 2 and Example 3 included the same superabsorbent particles and different adhesives. Comparative Example 2 included an adhesive having a bulk contact angle of 110.6°. Example 3 included an adhesive modified with ionization chemistries or additives. Table 3 provides the composition of the composite and the properties for each of Comparative Example 2 and Example 3. TABLE 3 Adhesive Wt. % SAP Wt. % Total Polar Basicity Adhesive SAP Surface Surface Contant Energy Energy @ 0.01 (mj / m2) (mj / m2) surface @ 0.01 @ 0.01 coverage surface surface coverage coverage Comp. Ex.2 Henkel 5 LK601N 95 116 10 0.78 5402U Example 3 Modified 5 LK601N 95 130 12.1 0.85 Adhesive 29 US2008232505803PATENT Attorney Docket No.: 109296-1339857

[0094] FIGs.4 and 5 provide graphs of the total surface energy (mj / m2) and polar surface energy (mj / m2) in relation to surface coverage for Comparative Example 2 and Example 3, respectively. FIG.6 is a graph of the basicity constant (Kb) in relation to surface coverage for Comparative Example 2 and Example 3. Notably, Example 3 had a higher total surface energy, polar surface energy, and basicity constant compared to Comparative Example 2. As shown in Table 4 below, Example 3 had a lower intake time on the initial insult for all aged composites. TABLE 4 Cradle Intake Time (s) 1st(T=0) 1st2nd(T=0) 2nd(Aged) 3rd(T=0) 3rd(Aged) (Aged) Comp. Ex.2 37.2 60.1 26.0 41.7 142 257.6 Example 3 29.1 46.7 26.2 25.4 155.7 240.6

[0095] Sample composites were tested to investigate the effect of processing conditions on fluid intake for the composites described herein. Five samples were tested, each including 5 wt. % adhesive (Henkel 5402U) and 95 wt. % superabsorbent particles (LK601N). The process of producing the composite included depositing superabsorbent particles onto an absorbent material. As the superabsorbent particles fell towards the absorbent material, adhesive applicators sprayed adhesive toward the falling superabsorbent material. The adhesive was heated to a processing temperature from 285 °F to 360 °F prior to being sprayed onto the superabsorbent particles. Table 5 provides the processing conditions for Examples 4-8 and the Brunauer-Emmett-Teller (BET) surface area of the composite was measured using inverse gas chromatography. The BET surface area was measured after initial production of the composite without aging (T=0) and after aging the composite for two weeks at a temperature from 50 °C to 60 °C at an average relative humidity less than 10 %. TABLE 5 Application Composite Composite 1stCradle Temp. BET (m2 / g) BET (m2 / g) Intake (° F) (T=0) (Aged) Time (s) Example 4 285 ~ 0.584 ~ 0.615 24.6 Example 5 302 ~ 0.615 ~ 0.616 32.1 Example 6 320 ~ 0.627 ~ 0.639 37.2 Example 7 338 ~ 0.681 ~ 0.659 40.3 30 US2008232505803PATENT Attorney Docket No.: 109296-1339857 Example 8 356 ~ 0.625 ~ 0.635 37.8

[0096] As shown in Table 5, the temperature of the adhesive that is sprayed on the composite to fix the superabsorbent particles in place can affect the fluid intake time. At higher temperatures, the composite is susceptible to more adhesive-related BET surface area which can increase intake time. However, higher temperatures for adhesive application provide better superabsorbent particle fixation. The processing temperature can beneficially provide a balance of fixing the superabsorbent particles in place and limiting the amount of adhesive-related BET surface area on the composite.

[0097] All patents, publications and abstracts cited above are incorporated herein by reference in their entireties. Various embodiments of the invention have been described in fulfillment of the various objectives of the invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptions thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the present invention as defined in the following claims.

[0098] While the invention has been described in detail with respect to the specific embodiments thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily conceive of alterations to, variations of, and equivalents to these embodiments. Accordingly, the scope of the present invention should be assessed as that of the appended claims and any equivalents thereto and the following embodiments: Embodiments

[0099] Embodiment 1: A composite comprising: a mixture of superabsorbent particles and an adhesive, wherein the adhesive is dispersed throughout the superabsorbent particles; and an ionization chemistry or additive disposed on the adhesive; wherein the composite has a total surface energy greater than 122 mj / m2at 1 % fractional surface coverage; wherein the ionization chemistry or additive disposed on the adhesive increases an ionization level of the superabsorbent particles by at least 1 %. 31 US2008232505803PATENT Attorney Docket No.: 109296-1339857

[0100] Embodiment 2: The embodiment of any preceding or subsequent embodiment, wherein the composite comprises less than 6 wt. % of adhesive based on the total weight of the superabsorbent particles.

[0101] Embodiment 3: The embodiment of any preceding or subsequent embodiment, wherein the ionization chemistry or additive disposed on the adhesive comprises from 0.10 to 5.0 wt. %, based on the total weight of the adhesive.

[0102] Embodiment 4: The embodiment of any preceding or subsequent embodiment, wherein a bulk contact angle of the adhesive ranges from 50° to 80°.

[0103] Embodiment 5: The embodiment of any preceding or subsequent embodiment, wherein the adhesive comprises one or more of inorganic hydroxides, carbonates, bicarbonates, oxides, and phosphate salts, organic hydroxides, quaternary ammonium salts, amino acids, amino acids- related salts, polymeric amines, polymeric imines, polycarbonates, polymeric phosphate salts, polyacrylic acids sodium salts, and polymeric quaternary ammonium salts.

[0104] Embodiment 6: The embodiment of any preceding or subsequent embodiment, wherein the composite comprises a total surface energy from 122 mj / m2to 160 mj / m2at 1 % fractional surface coverage.

[0105] Embodiment 7: The embodiment of any preceding or subsequent embodiment, wherein the superabsorbent particles comprise an average particle size ranging from about 150 microns to 850 microns.

[0106] Embodiment 8: The embodiment of any preceding or subsequent embodiment, wherein the adhesive comprises a storage modulus strength ranging from 0.5 x 10^4 Pa to 10.0 x 10^4 Pa at temperature range of 25 °C to 37 °C.

[0107] Embodiment 9: The embodiment of any preceding or subsequent embodiment, wherein the adhesive comprises a storage modulus strength ranging from 1.0 x 10^4 Pa to 10.0 x 10^4 Pa at temperature range of 25 °C to 37 °C.

[0108] Embodiment 10: The embodiment of any preceding or subsequent embodiment, wherein the composite has a polar surface energy ranging from 8 mj / m2to 18 mj / m2at 1 % fractional surface coverage. 32 US2008232505803PATENT Attorney Docket No.: 109296-1339857

[0109] Embodiment 11: The embodiment of any preceding or subsequent embodiment, wherein the superabsorbent particles comprise an initial neutralization level of at least 70%.

[0110] Embodiment 12: An absorbent core comprising: a first substrate material having a first surface and a second surface; a second substrate material having a first surface and a second surface; and a composite disposed between the first substrate and the second substrate, wherein the composite comprises superabsorbent particles, an adhesive, and an ionization chemistry or additive disposed on the adhesive; wherein the composite has a basicity constant (Kb) greater than 0.78 at 1 % fractional surface coverage.

[0111] Embodiment 13: The embodiment of any preceding or subsequent embodiment, wherein a bulk contact angle of the adhesive ranges from 50° to 80°.

[0112] Embodiment 14: The embodiment of any preceding or subsequent embodiment, wherein the composite comprises a total surface energy from 122 mj / m2to 160 mj / m2at 1 % fractional surface coverage.

[0113] Embodiment 15: The embodiment of any preceding or subsequent embodiment, wherein the composite comprises a polar surface energy of at least 10.1 mj / m2at 1 % fractional surface coverage.

[0114] Embodiment 16: The embodiment of any preceding or subsequent embodiment, wherein the composite is substantially free from fluff.

[0115] Embodiment 17: The embodiment of any preceding or subsequent embodiment, wherein the superabsorbent particles comprise an initial neutralization level of at least 70%.

[0116] Embodiment 18: The embodiment of any preceding or subsequent embodiment, wherein the adhesive comprises a storage modulus strength ranging from 0.5 x 10^4 Pa to 10.0 x 10^4 Pa at temperature range of 25 °C to 37 °C.

[0117] Embodiment 19: A method of producing a composite, the method comprising: providing superabsorbent particles; providing an adhesive; depositing the superabsorbent particles on a substrate; and spraying the adhesive on the superabsorbent particles while the superabsorbent particles are being deposited on the substrate to produce a composite; wherein 33 US2008232505803PATENT Attorney Docket No.: 109296-1339857 the composite has a polar surface energy greater than 10.1 mj / m2at 1 % fractional surface coverage.

[0118] Embodiment 20: The embodiment of any preceding or subsequent embodiment, wherein the adhesive sprayed onto the superabsorbent particles is a rubber-based adhesive.

[0119] Embodiment 21: The embodiment of any preceding or subsequent embodiment, further comprising aging the composite deposited on the substrate at a temperature less than 55 °C for a period up to two weeks.

[0120] Embodiment 22: The embodiment of any preceding or subsequent embodiment, wherein depositing the superabsorbent particles comprises: supplying the superabsorbent particles to a chute; and metering an amount of superabsorbent particles falling from the chute onto the substrate.

[0121] Embodiment 23: The embodiment of any preceding or subsequent embodiment, wherein the adhesive is sprayed onto the superabsorbent particles as the superabsorbent particles are falling from the chute to the substrate.

[0122] Embodiment 24: A composite comprising: a mixture of superabsorbent particles and an adhesive, wherein the adhesive is dispersed throughout the superabsorbent particles; wherein the composite has a basicity constant (Kb) greater than 0.78 at 1 % fractional surface coverage.

[0123] Embodiment 25: A composite comprising: a mixture of superabsorbent particles and an adhesive, wherein the adhesive is dispersed throughout the superabsorbent particles; wherein the composite has a polar surface energy greater than 10.1 mj / m2at 1 % fractional surface coverage. 34 US2008232505803

Claims

PATENT Attorney Docket No.: 109296-1339857 WHAT IS CLAIMED IS:

1. A composite comprising: a mixture of superabsorbent particles and an adhesive, wherein the adhesive is dispersed throughout the superabsorbent particles; and an ionization chemistry or additive disposed on the adhesive; wherein the composite has a total surface energy greater than 122 mj / m2at 1 % fractional surface coverage; wherein the ionization chemistry or additive disposed on the adhesive increases an ionization level of the superabsorbent particles by at least 1 %.

2. The composite of claim 1, wherein the composite comprises less than 6 wt. % of adhesive based on the total weight of the superabsorbent particles.

3. The composite of claim 1, wherein the ionization chemistry or additive disposed on the adhesive comprises from 0.10 to 5.0 wt. %, based on the total weight of the adhesive.

4. The composite of claim 1, wherein a bulk contact angle of the adhesive ranges from 50° to 80°.

5. The composite of claim 1, wherein the adhesive comprises one or more of inorganic hydroxides, carbonates, bicarbonates, oxides, and phosphate salts, organic hydroxides, quaternary ammonium salts, amino acids, amino acids-related salts, polymeric amines, polymeric imines, polycarbonates, polymeric phosphate salts, polyacrylic acids sodium salts, and polymeric quaternary ammonium salts.

6. The composite of claim 1, wherein the composite comprises a total surface energy from 122 mj / m2to 160 mj / m2at 1 % fractional surface coverage.

7. The composite of claim 1, wherein the superabsorbent particles comprise an average particle size ranging from about 150 microns to 850 microns.

8. The composite of claim 1, wherein the adhesive comprises a storage modulus strength ranging from 0.5 x 10^4 Pa to 10.0 x 10^4 Pa at temperature range of 25 °C to 37 °C. 35 US2008232505803PATENT Attorney Docket No.: 109296-1339857 9. The composite of claim 1, wherein the adhesive comprises a storage modulus strength ranging from 1.0 x 10^4 Pa to 10.0 x 10^4 Pa at temperature range of 25 °C to 37 °C.

10. The composite of claim 1, wherein the composite has a polar surface energy ranging from 8 mj / m2to 18 mj / m2at 1 % fractional surface coverage.

11. The composite of claim 1, wherein the superabsorbent particles comprise an initial neutralization level of at least 70%.

12. An absorbent core comprising: a first substrate material having a first surface and a second surface; a second substrate material having a first surface and a second surface; and a composite disposed between the first substrate material and the second substrate material, wherein the composite comprises superabsorbent particles, an adhesive, and an ionization chemistry or additive disposed on the adhesive; wherein the composite has a basicity constant (Kb) greater than 0.78 at 1 % fractional surface coverage.

13. The absorbent core of claim 12, wherein a bulk contact angle of the adhesive ranges from 50° to 80°.

14. The absorbent core of claim 12, wherein the composite comprises a total surface energy from 122 mj / m2to 160 mj / m2at 1 % fractional surface coverage.

15. The absorbent core of claim 12, wherein the composite comprises a polar surface energy of at least 10.1 mj / m2at 1 % fractional surface coverage.

16. The absorbent core of claim 12, wherein the composite is substantially free from fluff.

17. The absorbent core of claim 12, wherein the superabsorbent particles comprise an initial neutralization level of at least 70%.

18. The absorbent core of claim 12, wherein the adhesive comprises a storage modulus strength ranging from 0.5 x 10^4 Pa to 10.0 x 10^4 Pa at temperature range of 25 °C to 37 °C. 36 US2008232505803PATENT Attorney Docket No.: 109296-1339857 19. A method of producing a composite, the method comprising: providing superabsorbent particles; providing an adhesive; depositing the superabsorbent particles on a substrate; and spraying the adhesive on the superabsorbent particles while the superabsorbent particles are being deposited on the substrate to produce a composite; wherein the composite has a polar surface energy greater than 10.1 mj / m2at 1 % fractional surface coverage.

20. The method of claim 19, wherein the adhesive sprayed onto the superabsorbent particles is a rubber-based adhesive.

21. The method of claim 19, further comprising aging the composite deposited on the substrate at a temperature less than 55 °C for a period up to two weeks.

22. The method of claim 19, wherein depositing the superabsorbent particles comprises: supplying the superabsorbent particles to a chute; and metering an amount of superabsorbent particles falling from the chute onto the substrate.

23. The method of claim 19, wherein the adhesive is sprayed onto the superabsorbent particles as the superabsorbent particles are falling from the chute to the substrate.

24. A composite comprising: a mixture of superabsorbent particles and an adhesive, wherein the adhesive is dispersed throughout the superabsorbent particles; wherein the composite has a basicity constant (Kb) greater than 0.78 at 1 % fractional surface coverage.

25. A composite comprising: a mixture of superabsorbent particles and an adhesive, wherein the adhesive is dispersed throughout the superabsorbent particles; 37 US2008232505803PATENT Attorney Docket No.: 109296-1339857 wherein the composite has a polar surface energy greater than 10.1 mj / m2at 1 % fractional surface coverage. 38 US2008232505803

Images