Odor-suppressing absorbent material, absorbent article, and related methods of use and methods of manufacture

Abstract

Described are absorbent materials configured to sequester trimethylamine (TMA), absorbent articles made from the absorbent materials, related methods of use, methods for measuring the reduction of free TMA, and related methods of making absorbent articles. [Selected Figure] Figure 1

Description

Background Art

[0001] Trimethylamine (TMA) is a chemical substance that has a strong fishy odor even at low concentrations and is the cause of the fishy odor that is a symptom of bacterial vaginitis. During and after menstruation, an increase in the pH of the vaginal environment is common. The pH of the vagina is usually 4 - 4.5, but during menstruation, the vaginal pH can increase up to 6.6. This increase in pH may promote the abnormal growth of anaerobic bacteria and sometimes result in an increase in the amount of TMA released from the more alkaline environment of the vagina.

[0002] Feminine hygiene products, such as sanitary napkins, are products commonly used to absorb menstrual fluid, bleeding, and urinary incontinence leaks. Since these products absorb fluids that can emit bad odors (such as those containing TMA), are held close to the body with a minimum air flow, and are worn for several hours, there is a risk that bad odors will be concentrated in these products. For this reason, TMA is a chemical of high interest in terms of odor suppression for feminine hygiene products.

[0003] Currently, absorbent hygiene products that promote odor suppression do so using fragrances, antibacterial properties, activated carbon, or "odor lock" technology. However, conventional absorbent hygiene products have not particularly attempted to address the bad odor associated with TMA, for example, by sequestering TMA.

[0004] TMA is also associated with meat products, especially fish products. Bacteria and fish enzymes convert TMA oxide present in fish meat into TMA. Absorbent pads contained in meat packaging absorb gravy and other liquids associated with meat products. However, conventional absorbent pads for meat packaging do not sequester TMA associated with meat products or otherwise reduce the TMA odor.

Summary of the Invention

Problems to be Solved by the Invention

[0005] Accordingly, there has been a long-standing need for absorbent products that absorb liquids and sequester TMA, thereby reducing TMA malodor. The present disclosure seeks to meet these needs and provide further related advantages.

[0006] The summary of the invention is provided in a simplified form in order to introduce a selection of concepts that are further described below in the detailed description of the invention. The summary of the invention is not intended to identify key features of the claimed subject matter nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

Means for Solving the Problems

[0007] In one aspect, the present disclosure provides a method for reducing free TMA, comprising contacting trimethylamine ("TMA") molecules with an absorbent material comprising a cellulose fiber matrix and a carboxylic acid linked to the cellulose fiber matrix, wherein the reduction of free TMA is a comparison with a control.

[0008] In another aspect, the present disclosure provides a method for sequestering TMA molecules, comprising contacting the TMA molecules with an absorbent material comprising a cellulose fiber matrix and a carboxylic acid linked to the cellulose fiber matrix.

[0009] In yet another aspect, the present disclosure provides an absorbent article comprising an absorbent material, wherein the absorbent material comprises a fiber matrix and a carboxylic acid linked to the fiber matrix, the fiber matrix comprises fibers selected from the group consisting of cellulose fibers and cellulose-derived fibers, and the absorbent article is a feminine hygiene product or a meat packaging pad.

[0010] In another aspect, the present disclosure provides a method for measuring the reduction of free TMA sequestered by an absorbent material, including contacting an absorbent material disposed in a container with an amount of TMA; withdrawing a portion of the gas headspace of the container; measuring the amount of free TMA in the withdrawn portion of the gas headspace; and determining the reduction of free TMA in the gas headspace by comparison with a control.

[0011] In yet another aspect, the present disclosure provides a method for making an absorbent article, including preparing an absorbent material including a fiber matrix and a carboxylic acid linked to the fiber matrix; and attaching a fluid-permeable top sheet and a fluid-impermeable bottom sheet to the absorbent material.

[0012] Many of the foregoing aspects and attendant advantages of the claimed subject matter will be more readily appreciated as the same becomes better understood by reference to the following detailed description, when considered in conjunction with the accompanying drawings.

Brief Description of the Drawings

[0013]

Figure 1

Detailed Description of the Invention

[0014] Absorbent materials configured to sequester trimethylamine (TMA), absorbent articles made therefrom, related methods of use, methods for measuring free TMA, methods for measuring the reduction of free TMA by comparison with a control, and related methods for making absorbent articles are described herein.

[0015] The detailed description set forth below is intended as a description of various embodiments of the disclosed subject matter in connection with the accompanying figures and is not intended to represent the only embodiments. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or advantageous over other embodiments. The exemplary embodiments provided herein are not intended to be exhaustive or to limit the claimed subject matter to the exact form disclosed.

[0016] In the following description, numerous specific details are set forth in order to provide a thorough understanding of one or more embodiments of the present disclosure. However, it will be apparent to one of ordinary skill in the art that many embodiments of the present disclosure may be practiced without some or all of these specific details. In some instances, well-known methods, procedures have not been described in detail so as not to unnecessarily obscure various aspects of the present disclosure. Further, it will be recognized that embodiments of the present disclosure may be used in any combination of the features described herein. Absorbent material In one aspect, the present disclosure provides an absorbent material configured to sequester TMA. As used herein, "sequester" means to absorb, adsorb, reduce, bind, neutralize, and / or remove TMA. In this regard, the absorbent materials described herein are configured to remove TMA from, for example, the gas and liquid phases in contact with the absorbent material by sequestering the TMA. As further contemplated herein, such sequestration reduces the levels of free TMA in the gas and liquid phases.

[0017] In one embodiment, the absorbent material described herein includes a fiber matrix and a carboxylic acid coupled to the fiber matrix. As further described herein, many carboxylic acids are water-soluble and thus an aqueous treatment or other solution-based treatment can be applied to couple the carboxylic acid to the fiber matrix. Certain conventional absorbent materials use powders of non-carboxylic acid compositions, such as activated charcoal and activated carbon, for odor suppression. In practice, the odor suppressing components of such powders tend to agglomerate, are often flammable, and can become airborne, causing a risk of contamination and inhalation.

[0018] Furthermore, many carboxylic acids are readily available and inexpensive, making them suitable for inclusion in products containing absorbent materials. Moreover, many carboxylic acids are also colorless and thus can be included in the absorbent material, for example, without changing the color of the fiber matrix of the absorbent material. This is in contrast to certain conventional odor suppressing components having a dark color, such as activated charcoal and activated carbon, which are used in some conventional absorbent articles and darken the color of the absorbent article.

[0019] In one embodiment, the carboxylic acid is a polycarboxylic acid. In one embodiment, the polycarboxylic acid is a partially or fully neutralized salt. Without being bound by theory, as further discussed herein with respect to FIG. 1 and Example 1, the carboxylic acid groups of the carboxylic acid are thought to assist in the sequestration of TMA. Thus, since a polycarboxylic acid has two or more carboxylic acid groups per carboxylic acid molecule, each polycarboxylic acid molecule is thought to be configured to assist in sequestering more TMA molecules, for example, than a monocarboxylic acid.

[0020] In one embodiment, the carboxylic acid is selected from the group consisting of malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, propionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof. In yet another embodiment, the carboxylic acid is selected from the group consisting of citric acid, lactic acid, malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, propionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof. In another embodiment, the carboxylic acid is selected from the group consisting of citric acid, lactic acid, salts thereof, and combinations thereof. In one embodiment, the carboxylic acid is citric acid or a salt thereof.

[0021] In one embodiment, examples of the carboxylate include carboxylates selected from the group consisting of sodium salts, potassium salts, ammonium salts, other metal salts, and combinations thereof.

[0022] In one embodiment, the absorbent material comprises a carboxylic acid content between about 0.01 wt% and about 10 wt% (also described as weight percent herein). In one embodiment, the absorbent material comprises a carboxylic acid content between about 0.05 wt% and about 5 wt%. In one embodiment, the absorbent material comprises a carboxylic acid content between about 0.1 wt% and about 1 wt%. In one embodiment, the absorbent material comprises a carboxylic acid content of about 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.07 wt%, 0.08 wt%, or 0.09 wt%. In one embodiment, the absorbent material comprises a carboxylic acid content of about 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, or 0.9 wt%. In one embodiment, the absorbent material comprises a carboxylic acid content of about 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, or 9 wt%.

[0023] Furthermore, since the absorbent materials and absorbent articles described herein sequester TMA, components that mask the TMA odor (e.g., fragrances) are not necessary to reduce the TMA odor. Thus, in one embodiment, the absorbent materials described herein are fragrance-free. Such fragrance-free absorbent materials can be advantageous, for example, to users who have a sensitivity or allergy to fragrances or who prefer not to use products containing fragrances. It should also be noted that the absorbent materials and absorbent articles described herein can react with and sequester other basic molecules that have an odor.

[0024] In one embodiment, the fiber matrix comprises a cellulose pulp structure. In one embodiment, the cellulose pulp structure comprises a matrix of cellulose fibers, cellulose-based fibers, or combinations thereof, and a carboxylic acid linked to the fiber matrix. In one embodiment, the cellulose-based fibers are selected from the group consisting of viscose fibers, modal fibers, lyocell fibers, and combinations thereof. In one embodiment, the fiber matrix comprises fluff pulp. In one embodiment, the fiber matrix comprises southern bleached softwood kraft pulp.

[0025] In one embodiment, the fiber matrix comprises synthetic fibers. In one embodiment, the fiber matrix comprises non-woven synthetic fibers. In one embodiment, the fiber matrix comprises a mixture of synthetic and natural fibers.

[0026] As further contemplated herein, the absorbent materials described herein include carboxylic acids linked to a fiber matrix. In one embodiment, the carboxylic acid is linked directly to the fiber matrix without, for example, a binder, linker, or other intermediate composition or molecule between the carboxylic acid and the fiber matrix. In one embodiment, the carboxylic acid linked to the fiber matrix includes carboxylic acids covalently bonded to the fiber matrix. In one embodiment, the carboxylic acid linked to the fiber matrix includes carboxylic acids non-covalently bonded to the fiber matrix. Such non-covalent linkages can occur, for example, by hydrogen bonding, van der Waals forces, ionic bonding, and combinations thereof.

[0027] In one embodiment, the absorbent materials described herein do not include a binder, such as an organosilicon polymer binder, that is linked to the carboxylic acid and binds the carboxylic acid to the fiber matrix. Without being bound by theory, it is believed that in certain embodiments, the carboxylic acid is configured to be directly linked to the fiber matrix itself without the need for a binder. For example, in certain embodiments, the fiber matrix is a natural fiber that includes hydroxyl groups that link to the carboxylic acid without a binder, such as an organosilicon polymer binder.

[0028] In this regard, absorbent materials that include carboxylic acids directly linked to a fiber matrix and absorbent articles made therefrom do not require a pouch or other enclosed container to contain, for example, powders (such as activated charcoal or activated carbon) that may leak from the absorbent material or absorbent article.

[0029] In one embodiment, the carboxylic acid is applied to the fiber matrix in a solid form, such as a powder form or a granular form. In one embodiment, the solid carboxylic acid is linked to the fiber matrix with an adhesive. In one embodiment, the adhesive is a physical adhesive. In one embodiment, the adhesive is a chemical adhesive.

[0030] In one embodiment, the solid carboxylic acid is typically applied to a fiber matrix having a water content above the fiber saturation point ( “FSP”), which is typically about 20% to about 25% water by weight. Without being bound by theory, in certain embodiments, it is believed that when the solid carboxylic acid contacts the wet fiber matrix, it at least partially dissolves and attaches to the wet fiber matrix. Thus, for the fiber matrix in this embodiment, a water content of about 20% to about 99.9% water by weight is sufficient to at least partially dissolve the solid carboxylic acid.

[0031] In one embodiment, the absorbent material described herein does not contain or substantially does not contain inorganic peroxide (in this case, “substantially free of inorganic peroxide” is understood to mean an amount of inorganic peroxide between 0 wt% and 1 wt%, as limited by known detection methods).

[0032] The TMA blocking effect can also be observed by utilizing oxidized cellulose fibers, which can be produced by known methods (see, for example, U.S. Patent No. 8,007,635, which is hereby incorporated by reference in its entirety).

[0033] As described above, the absorbent material of the present disclosure is configured to block TMA. In one embodiment, the absorbent material of the present disclosure, at equilibrium at 25°C (in this case, “equilibrium” should be understood to mean the point at which the TMA entering the gas headspace of the test apparatus reaches a steady state), is configured to block about 6.15409×10 -5 g or more of TMA per gram of absorbent material, where the absorbent material is treated with 0.01% by weight of a carboxylic acid selected from one of the groups provided herein. In one embodiment, the absorbent material is configured to block about 6.15409×10 -5 g or more of TMA per gram of absorbent material at equilibrium at 25°C, where the absorbent material is treated with 0.01% by weight of citric acid.

[0034] As further contemplated herein with respect to the methods of the present disclosure, in one embodiment, the amount of TMA sequestered by the absorbent material described herein is determined by measuring the amount of TMA in the gas headspace of a closed container holding the absorbent material and the initial amount of TMA. In one embodiment, determining the amount of free TMA upon sequestration of TMA by the absorbent material comprises contacting a known amount of the absorbent material disposed in a closed container with an initial known amount of TMA; exposing the absorbent material to the initial amount of TMA and allowing equilibrium to be reached within the gas headspace, then withdrawing a portion of the gas headspace from the closed container; and measuring the gas concentration of TMA (e.g., in ppm) in the withdrawn portion of the gas headspace.

[0035] In one embodiment, the gas headspace has a volume of less than 1 L. In one embodiment, the gas headspace has a volume of about 0.5 L. In one embodiment, the container is a flexible container.

[0036] As further contemplated herein, in one embodiment, the amount of TMA sequestered by the absorbent material is measured relative to a control absorbent material, e.g., a control absorbent material that does not contain a carboxylic acid linked to a fiber matrix, as further contemplated herein with respect to Example 1, or the control sample can be performed using a container that does not contain the absorbent material (i.e., an empty control).

[0037] In one embodiment, the absorbent material described herein is configured to sequester TMA from a solution in contact with the absorbent material and to sequester TMA from the gas phase in contact with the absorbent material. In this regard, the absorbent material is configured to remove or reduce TMA malodor by sequestering both gaseous TMA and dissolved or liquid TMA.

[0038] As further contemplated herein, the absorbent materials of the present disclosure are configured to sequester TMA. In one embodiment, by quantifying the ability to sequester TMA, the absorbent material is configured to reduce the gas concentration of free TMA in the gas headspace of a test apparatus (described in detail below) by 50% as compared to a control (see above for discussion of appropriate controls). In one embodiment, the absorbent material is configured to reduce the amount of free TMA entering (or that would otherwise enter) the gas headspace by 75% as compared to a control. In one embodiment, the absorbent material is configured to reduce the amount of free TMA entering (or that would otherwise enter) the gas headspace by 85% as compared to a control. In one embodiment, the absorbent material is configured to reduce the amount of free TMA entering (or that would otherwise enter) the gas headspace by 90% as compared to a control. In one embodiment, the absorbent material is configured to reduce the amount of free TMA entering (or that would otherwise enter) the gas headspace by 95% as compared to a control. In one embodiment, the absorbent material is configured to reduce the amount of free TMA entering (or that would otherwise enter) the gas headspace by 99% as compared to a control. In one embodiment, the absorbent material is configured to reduce the amount of free TMA entering (or that would otherwise enter) the gas headspace by substantially 100% as compared to a control (wherein "substantially 100%" is to be understood to mean an amount between 99% and 100% as limited by the detection methods described herein).

[0039] As further contemplated herein, in one embodiment, the cellulose fiber matrix of the absorbent material can reduce free TMA from the gas headspace by sequestering the TMA. In one embodiment, when the absorbent material contains 0.45 wt% citric acid, the TMA is introduced into a solution of about 0.034 wt%, and the control is an equal amount of absorbent material consisting of southern bleached softwood kraft fluff pulp that is substantially free of any added carboxylic acid, the cellulose fiber matrix of the absorbent material can reduce free TMA by at least about 95 ppm in a gas headspace of about 0.5 L. In this context, "equal amount" is limited by known detection methods and should be understood to mean the amount of control fluff pulp having a mass between 95% and 105% of the mass of the absorbent material.

[0040] In one embodiment, when the absorbent material contains 0.45 wt% citric acid, the TMA is introduced into a solution of about 0.027 wt%, and the control is an equal amount of absorbent material consisting of southern bleached softwood kraft fluff pulp that is substantially free of any added carboxylic acid, the cellulose fiber matrix can reduce free TMA by at least about 99% in a gas headspace of about 0.5 L. In one embodiment, when the absorbent material contains 0.45 wt% citric acid, the TMA is introduced into a solution of about 0.05 wt%, and the control is an equal amount of absorbent material consisting of southern bleached softwood kraft fluff pulp that is substantially free of any added carboxylic acid, the cellulose fiber matrix can reduce free TMA by at least about 50% in a gas headspace of about 0.5 L.

[0041] As further contemplated herein with respect to methods of reducing the amount of free TMA, in one embodiment, the measurement of the reduction of free TMA sequestered by the absorbent material of the present disclosure comprises contacting the absorbent material disposed in a container with an amount of TMA; withdrawing a portion of the gas headspace of the container; measuring the amount of free TMA in the withdrawn portion of the gas headspace; and determining the reduction of free TMA in the gas headspace by comparison to a control.

[0042] In one embodiment, the absorbent material described herein may optionally further include additives selected from the group consisting of activated charcoal, activated carbon, fragrance, zeolite, and combinations thereof. While the absorbent materials of the present disclosure are configured to sequester TMA without such additives, in certain embodiments, the absorbent materials further include materials including, but not limited to, activated charcoal, activated carbon, zeolite, or fragrance, configured to, for example, non-selectively absorb or mask certain other malodors or to supplement other TMA malodor suppressing components of the absorbent material.

[0043] In one embodiment, the absorbent material further includes a superabsorbent polymer to assist in the absorption of fluids. Absorbent article In another aspect, the present disclosure provides an absorbent article including the absorbent materials of the present disclosure. As further discussed herein, the suppression and prevention of odors, particularly those related to TMA odor, in feminine hygiene products and meat packaging products are of concern. Since the absorbent materials of the present disclosure are configured to sequester TMA, they are particularly suitable for use in feminine hygiene products and meat packaging products.

[0044] Accordingly, in one embodiment, the absorbent article includes a fibrous matrix and a carboxylic acid coupled to the fibrous matrix. In one embodiment, the fibrous matrix includes fibers selected from the group consisting of cellulose fibers, cellulose-based fibers, and combinations thereof.

[0045] In one embodiment, the absorbent article includes a fluid-permeable topsheet. The fluid-permeable topsheet includes, for example, a highly fluid-permeable material configured to transfer liquid from the wearer to the absorbent material. In one embodiment, the fluid-permeable topsheet includes a material selected from the group consisting of a hydrophilic woven fabric, a hydrophilic nonwoven fabric, an airlaid sheet, a wet-laid sheet, a membrane including apertures, an open-cell foam, and batting.

[0046] In one embodiment, the absorbent article includes a fluid-impermeable backsheet. The fluid-impermeable backsheet is configured to prevent liquid from moving from the absorbent material through the fluid-impermeable sheet, for example, to the wearer's clothing.

[0047] In one embodiment, the absorbent material forms at least a portion of the absorbent core of the absorbent article. In one embodiment, the absorbent material is disposed between a fluid-permeable topsheet and a fluid-impermeable backsheet. In one embodiment, the fluid-permeable topsheet and the fluid-impermeable backsheet are preferably sealed around the absorbent material. In one embodiment, the absorbent material is disposed within the fluid-permeable topsheet.

[0048] In one embodiment, the absorbent article is a feminine hygiene product. As further described herein, in one embodiment, the absorbent material described herein includes a fiber matrix and a carboxylic acid linked to the fiber matrix. In this regard, without being bound by theory, as further discussed herein, the absorbent article including the absorbent material of the present disclosure is believed to reduce TMA odor associated with vaginal fluid in at least two ways: (1) the carboxylic acid reduces the pH of the vagina, thereby inhibiting the growth of anaerobic bacteria, and (2) the carboxylic acid sequesters TMA molecules, thereby reducing free TMA.

[0049] In one embodiment, the feminine hygiene product is selected from the group consisting of panty liners, sanitary napkins, postpartum absorbent pads, light incontinence pads, interlabial pads, disposable menstrual protection underwear, and tampons. In one embodiment, the feminine hygiene product is selected from the group consisting of panty liners, sanitary napkins, postpartum absorbent pads, light incontinence pads, interlabial pads, and disposable menstrual protection underwear. In some embodiments, the absorbent article of the present disclosure is not in the form of a tampon. The feminine hygiene product can be manufactured by known methods (see, for example, U.S. Patent No. 9,717,817, which is incorporated herein by reference in its entirety, and the patents referred to therein).

[0050] In one embodiment, the feminine hygiene product is configured to be worn externally. As used herein, a feminine hygiene product configured to be worn externally is configured to be worn outside of the vagina. In one embodiment, the feminine hygiene product is not configured to be worn internally. As used herein, a feminine hygiene product configured to be worn internally is a feminine hygiene product configured to be worn at least partially inside the vagina.

[0051] In one embodiment, the absorbent material in the feminine hygiene product includes an absorbent material including a fiber matrix and a carboxylic acid linked to the fiber matrix, wherein the absorbent material includes a carboxylic acid content between about 0.01 wt% and about 10 wt%.

[0052] In one embodiment, the absorbent article is a meat packaging pad. The meat packaging pad may include those known in the art and may be manufactured by known methods (see, e.g., U.S. Patent Nos. 5,908,649 and 7,655,829, which are hereby incorporated by reference in their entirety). As further described herein, the TMA odor emanates from meat products, such as fish products, and it is necessary to block TMA in meat packaging products. Since the absorbent materials described herein are configured to block TMA, they are particularly suitable for use in meat packaging products. In one embodiment, the meat packaging product is a meat packaging pad. In one embodiment, the meat packaging pad is a fish packaging pad. In one embodiment, the meat packaging pad containing the absorbent material of the present disclosure is configured to absorb gravy, such as fish gravy, and other liquids and to block TMA.

[0053] In one embodiment, the absorbent material in the meat packaging pad includes a fiber matrix and a carboxylic acid linked to the fiber matrix, wherein the absorbent material includes a carboxylic acid content between about 0.01 wt% and about 10 wt%. In one embodiment, the meat packaging pad includes a superabsorbent polymer to assist in the absorption of fluids. In one embodiment, the superabsorbent polymer is disposed within the absorbent material. Method for reducing free TMA As further described herein, for example, TMA molecules from vaginal fluid or gravy, and the resulting TMA odor, can be reduced through the sequestration of TMA by the absorbent materials or absorbent articles of the present disclosure. By sequestering TMA in the absorbent material or an absorbent article made therefrom, the TMA odor is reduced, for example, such that free TMA is present at levels where it cannot be smelled by the human nose, or at significantly reduced levels where it can be smelled by the human nose, as compared to similar scenarios where TMA is not sequestered.

[0054] Accordingly, in another aspect, the present disclosure provides a method for reducing free TMA. As used herein, "free TMA" means an amount of TMA that is in the gas headspace or would equilibrate to the gas headspace and is measurable and / or smellable by the human nose. Free TMA is, for example, in contrast to TMA molecules sequestered by an absorbent material or absorbent article and is thus not available for measurement or detection by the human nose.

[0055] In one embodiment, a method of reducing the level of free TMA includes contacting TMA molecules with an absorbent material comprising a cellulose fiber matrix and a carboxylic acid linked to the cellulose fiber matrix. In one embodiment, the method further includes sequestering the TMA molecules.

[0056] As further described herein, the absorbent materials of the present disclosure and absorbent articles made therefrom are configured to sequester TMA from either or both of the liquid phase and / or the gas phase. Thus, in one embodiment, contacting the absorbent material or absorbent article with TMA includes contacting TMA in the solution phase, e.g., TMA dissolved in vaginal fluid, menstrual secretions, or gravy. In one embodiment, the TMA molecules are in a liquid. In one embodiment, the liquid TMA is TMA molecules dissolved in a solution or suspension. In one embodiment, the liquid TMA is pure liquid TMA. In one embodiment, contacting the absorbent material or absorbent article with TMA includes contacting the absorbent material or absorbent article with menstrual fluid containing TMA. In one embodiment, contacting the absorbent material or absorbent article with TMA includes contacting the absorbent material or absorbent article with a meat fluid, e.g., a fish meat fluid containing TMA.

[0057] Similarly, in one embodiment, contacting the absorbent material or absorbent article with TMA includes contacting TMA in the gas phase, e.g., TMA volatilization from vaginal fluid, menstrual secretions, or gravy.

[0058] In one embodiment, the absorbent material is any of the absorbent materials described herein. In one embodiment, the absorbent article is any of the absorbent articles described herein. In one embodiment, the fiber matrix is a cellulose fiber matrix (see below).

[0059] In one embodiment, the carboxylic acid is selected from the group consisting of malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, propionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof. In one embodiment, the carboxylic acid is selected from the group consisting of citric acid, lactic acid, malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, propionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof. In one embodiment, the carboxylic acid is citric acid or a salt thereof.

[0060] In one embodiment, the absorbent material comprises a carboxylic acid content between about 0.01 wt% and about 10 wt%. In one embodiment, the absorbent material comprises a carboxylic acid content between about 0.05 wt% and about 5 wt%. In one embodiment, the absorbent material comprises a carboxylic acid content between about 0.1 wt% and about 1 wt%. In one embodiment, the absorbent material comprises a carboxylic acid content of about 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.07 wt%, 0.08 wt%, or 0.09 wt%. In one embodiment, the absorbent material comprises a carboxylic acid content of about 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, or 0.9 wt%. In one embodiment, the absorbent material comprises a carboxylic acid content of about 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, or 9 wt%.

[0061] In one embodiment, the fiber matrix comprises a cellulose pulp structure. In one embodiment, the cellulose pulp structure comprises a matrix of cellulose fibers, cellulose-based fibers, or combinations thereof, and a carboxylic acid linked to the fiber matrix. In one embodiment, the cellulose-based fibers are selected from the group consisting of viscose fibers, modal fibers, lyocell fibers, and combinations thereof. In one embodiment, the fiber matrix comprises fluff pulp. In one embodiment, the fiber matrix comprises southern bleached softwood kraft pulp.

[0062] In one embodiment, the fiber matrix comprises synthetic fibers. In one embodiment, the fiber matrix comprises non-woven synthetic fibers. In one embodiment, the fiber matrix comprises a mixture of synthetic and natural fibers.

[0063] In one embodiment, contacting the TMA with an absorbent material or an absorbent article made therefrom reduces at least 50% of the free TMA available to exit from or re-enter the absorbent material or absorbent article as a gaseous compound. In one embodiment, contacting the TMA with an absorbent material or an absorbent article made therefrom reduces at least 75% of the free TMA available to exit from or re-enter the absorbent material or absorbent article as a gaseous compound. In one embodiment, contacting the TMA with an absorbent material or an absorbent article made therefrom reduces at least 85% of the free TMA available to exit from or re-enter the absorbent material or absorbent article. In one embodiment, contacting the TMA with an absorbent material or an absorbent article made therefrom reduces at least 95% of the free TMA available to exit from or re-enter the absorbent material or absorbent article. In one embodiment, contacting the TMA with an absorbent material or an absorbent article made therefrom reduces at least 99% of the free TMA available to exit from or re-enter the absorbent material or absorbent article. Method for measuring reduction of free TMA In another aspect, the present disclosure provides a method for measuring the reduction of free TMA trapped by an absorbent material, such as an absorbent material of the present disclosure or an absorbent article made therefrom. In one embodiment, the absorbent material is placed in a closed container and contacted with an amount of TMA. After the absorbent material has had the opportunity to trap at least a portion of the amount of TMA, for example, after the amount of TMA has reached equilibrium between the gas headspace of the closed container and the absorbent material, a portion of the gas headspace is withdrawn from the closed container. In one embodiment, prior to withdrawing a portion of the gas headspace from the closed container, the amount of TMA can be contacted with the absorbent material for a time sufficient to reach equilibrium, thereby also providing a time sufficient for at least a portion of the initial amount of TMA to be trapped within the absorbent material. One of ordinary skill in the art will readily know methods for creating an equilibrium curve or other suitable techniques for monitoring and confirming equilibrium.

[0064] In one embodiment, the closed container is a flexible container configured to at least partially collapse as a portion of the gas headspace is withdrawn. In this regard, withdrawing a portion of the gas headspace from the closed container is easier for the user.

[0065] The withdrawn portion of the gas headspace is analyzed to determine the gas concentration of free TMA present in the headspace. In one embodiment, measuring the amount of free TMA in the withdrawn portion involves passing the withdrawn portion of the gas headspace over a stationary phase loaded with a colorimetric analysis marker that changes color upon contact with TMA; and measuring the amount of color change in the stationary phase in response to passing the withdrawn portion of the gas headspace over the stationary phase. In one embodiment, analyzing the withdrawn portion of the gas headspace to measure the gas concentration of free TMA involves using a colorimetric analysis gas detection tube, such as the Sensidyne® gas detection tube system. While colorimetric analysis detection methods are described, it will be understood that other methods of TMA detection, such as, but not limited to, gas chromatography, can be used without conflicting with the methods of the present disclosure.

[0066] The reduction of free TMA is measured relative to a control. In one embodiment, the control is a blank control, where the blank control includes a control that does not involve contacting TMA molecules with the absorbent material. In one embodiment, the control is a control of the absorbent material, where the control of the absorbent material is an absorbent material that substantially has no or has no added carboxylic acid linked to the fiber matrix (in this case, "substantially no added carboxylic acid" or "substantially free of added carboxylic acid" should be understood to mean no added carboxylic acid or an amount of added carboxylic acid between 0 wt% and 1 wt% as limited by known detection methods). As used herein, "added carboxylic acid" should be understood to mean the amount of carboxylic acid that is added to or otherwise linked to the absorbent material during processing or manufacture in addition to any carboxylic acid present in the untreated absorbent material. In one embodiment, the control absorbent material includes fluff pulp, such as southern bleached softwood kraft pulp that has not been treated with or is not linked to carboxylic acid. In this regard, the user can determine the amount of TMA reduction by the carboxylic acid linked to the fiber matrix of the absorbent material described herein relative to the selected control.

[0067] In one embodiment, the amount of TMA (TMA g ) that is equilibrated in the gas headspace without being blocked by the absorbent material is compared to the amount of unblocked TMA (TMA c ) in a control experiment that is equilibrated in the control gas headspace. The reduction in the gas concentration of free TMA measured in the headspace above the absorbent material can be expressed as a percent reduction of free TMA (%TMA red ) relative to that of the control. This percent reduction can be calculated using the following equation.

[0068]

Equation

[0069] It should be noted that a fluid containing TMA, which is present on one side or other part of a closed container and is used to penetrate an absorbent material or absorbent article, may distort the results of TMA reduction. Such TMA-containing fluids that do not contact the absorbent material or absorbent article may result in increased volatilization of TMA from the TMA-containing solution into the gas headspace of the closed container. Such increased TMA volatilization results in a higher relative gaseous TMA concentration than when the TMA-containing solution directly penetrates onto the absorbent material or absorbent article, and may inaccurately indicate the ability (or lack thereof) of the absorbent material or absorbent article to sequester TMA. Method for Sequestering TMA As further described herein, absorbent materials and absorbent articles made therefrom can sequester TMA. Thus, in another aspect, the present disclosure provides a method for sequestering TMA molecules. In one embodiment, the method for sequestering TMA includes contacting the TMA molecules with an absorbent material comprising a fiber matrix and a carboxylic acid linked to the fiber matrix, or an absorbent article made therefrom. In one embodiment, the method further includes sequestering TMA molecules in the absorbent material or absorbent article made therefrom.

[0070] In one embodiment, the absorbent material is any of the absorbent materials described herein. In one embodiment, the absorbent article is any of the absorbent articles described herein. In one embodiment, the fiber matrix is a cellulose fiber matrix. In one embodiment, the cellulose fiber matrix includes a cellulose pulp structure. In one embodiment, the cellulose fiber matrix includes fibers selected from the group consisting of cellulose fibers and cellulose-based fibers. In one embodiment, the cellulose-based fibers are selected from the group consisting of viscose fibers, modal fibers, lyocell fibers, and combinations thereof.

[0071] In one embodiment, the carboxylic acid is selected from the group consisting of malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, propionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof. In one embodiment, the carboxylic acid is selected from the group consisting of citric acid, lactic acid, malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, propionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof. In one embodiment, the carboxylic acid is citric acid or a salt thereof.

[0072] In one embodiment, the absorbent material comprises a carboxylic acid content between about 0.01 wt% and about 10 wt%. In one embodiment, the absorbent material comprises a carboxylic acid content between about 0.05 wt% and about 5 wt%. In one embodiment, the absorbent material comprises a carboxylic acid content between about 0.1 wt% and about 1 wt%. In one embodiment, the absorbent material comprises a carboxylic acid content of about 0.01 wt%, 0.02 wt%, 0.03 wt%, 0.04 wt%, 0.05 wt%, 0.06 wt%, 0.07 wt%, 0.08 wt%, or 0.09 wt%. In one embodiment, the absorbent material comprises a carboxylic acid content of about 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, or 0.9 wt%. In one embodiment, the absorbent material comprises a carboxylic acid content of about 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, or 9 wt%.

[0073] In one embodiment, contacting the TMA molecule with the absorbent material or absorbent article comprises contacting a liquid, such as menstrual fluid containing TMA, with the absorbent material or an absorbent article made therefrom. In one embodiment, contacting the TMA molecule with the absorbent material comprises contacting a meat fluid containing the TMA molecule with the absorbent material or an absorbent article made therefrom. In one embodiment, the TMA molecule is in the gas phase and contacts the absorbent material or absorbent article.

[0074] In one embodiment, when the absorbent material contains 0.45% by weight of citric acid, the fiber matrix of the absorbent material of the present disclosure and the absorbent article made therefrom can block TMA molecules such that about 0.5 L of gas headspace contains less than about 1 ppm, 2 ppm, 3 ppm, 4 ppm, 5 ppm, 10 ppm, 20 ppm, 30 ppm, 40 ppm, or 50 ppm of free TMA in the equilibrium state. In one embodiment, when the absorbent material contains 0.01% by weight of citric acid and the TMA molecules are introduced into a solution between about 0.0005% by weight and about 0.034% by weight, the fiber matrix of the absorbent material of the present disclosure and the absorbent article made therefrom can block TMA molecules such that about 0.5 L of gas headspace contains less than about 50 ppm of free TMA in the equilibrium state. In one embodiment, when the absorbent material contains 0.01% by weight of citric acid and the TMA molecules are introduced into a solution of about 0.0005% by weight, 0.001% by weight, 0.005% by weight, 0.01% by weight, 0.015% by weight, 0.02% by weight, 0.025% by weight, 0.027% by weight, 0.03% by weight, 0.034% by weight, or 0.035% by weight, the fiber matrix of the absorbent material of the present disclosure and the absorbent article made therefrom can block TMA molecules such that about 0.5 L of gas headspace contains less than about 50 ppm of free TMA in the equilibrium state. In one embodiment, when the absorbent material contains 0.01% by weight of citric acid and the TMA molecules are introduced into a solution of about 0.034% by weight, the cellulose fiber matrix can block TMA molecules such that about 0.5 L of gas headspace contains less than about 10 ppm of free TMA in the equilibrium state. In one embodiment, when the absorbent material contains 0.01% by weight of citric acid and the TMA molecules are introduced into a solution of about 0.027% by weight, the cellulose fiber matrix can block TMA molecules such that about 0.5 L of gas headspace contains less than about 5 ppm of free TMA in the equilibrium state.

[0075] In one embodiment, when the absorbent material contains 0.01 wt% citric acid, TMA is introduced into a solution of about 0.034 wt%, and the control is the same amount of absorbent material consisting of southern bleached softwood kraft fluff pulp that is substantially free of any added carboxylic acid, the cellulose fiber matrix can reduce free TMA by at least about 95 ppm in a gas headspace of about 0.5 L.

[0076] In one embodiment, when the absorbent material contains 0.01 wt% citric acid, TMA is introduced into a solution of about 0.027 wt%, and the control is the same amount of absorbent material consisting of southern bleached softwood kraft fluff pulp that is substantially free of any added carboxylic acid, the cellulose fiber matrix can reduce free TMA by at least about 99% in a gas headspace of about 0.5 L. In one embodiment, when the absorbent material contains 0.01 wt% citric acid, TMA is introduced into a solution of about 0.05 wt%, and the control is the same amount of absorbent material consisting of southern bleached softwood kraft fluff pulp that is substantially free of any added carboxylic acid, the cellulose fiber matrix can reduce free TMA by at least about 50% in a gas headspace of about 0.5 L.

[0077] In one embodiment, determining the amount of free TMA after it has been sequestered by the absorbent material described herein includes contacting the absorbent material disposed in a container with an initial amount of TMA in solution; withdrawing a portion of the gas headspace of the container; and measuring the amount of free TMA in the withdrawn portion of the gas headspace, for example, in ppm. Measuring can be performed in any suitable manner, including the solid-phase colorimetric gas detector tubes, gas chromatography, etc. described herein. Without being bound by theory, TMA in the solution in contact with the absorbent material reacts with the carboxylic acid to form RCOO - N +It becomes a salt of (Me)3 and (reduce), thus blocking TMA by reducing the available TMA for volatilization, equilibrating into the gas headspace of the experimental container device, and thereby removing the TMA odor. Method for manufacturing an absorbent article As further described herein, the absorbent materials of the present disclosure and absorbent articles made therefrom are suitable as absorbent articles, such as absorbent cores or other absorbent portions of feminine hygiene products, because of their ability to block TMA. Thus, in another aspect, the present disclosure provides a method for manufacturing an absorbent article, such as a feminine hygiene product and a meat packaging pad, comprising the absorbent material of the present disclosure. In one embodiment, the method includes preparing an absorbent material comprising a fiber matrix and a carboxylic acid linked to the fiber matrix; and linking a fluid-permeable top sheet and a fluid-impermeable bottom sheet to the absorbent material. In one embodiment, preparing the absorbent material includes forming a cellulose pulp structure by forming a cellulose pulp sheet from a cellulose pulp slurry and forming a matrix of cellulose fibers from the cellulose pulp sheet. In one embodiment, the carboxylic acid is added by applying an acid in an aqueous form to the pulp sheet. As further described herein, in one embodiment, the carboxylic acid is added in solid form, for example, together with a binder or an adhesive.

[0078] In one embodiment, the absorbent material is any absorbent material described herein, comprising a fiber matrix and a carboxylic acid linked to the fiber matrix. In one embodiment, the fluid-permeable top sheet is any fluid-permeable top sheet described herein. In one embodiment, the fluid-impermeable bottom sheet is any fluid-impermeable bottom sheet described herein.

[0079] In one embodiment, the fluid-permeable top sheet and the fluid-impermeable bottom sheet are connected to the absorbent material by a connecting method selected from the group consisting of sewing, connection by an adhesive, heat sealing, ultrasonic welding, and combinations thereof.

[0080] In one embodiment, the fluid-permeable top sheet and the fluid-impermeable bottom sheet are connected around the absorbent material, and the absorbent material is disposed between the fluid-permeable top sheet and the fluid-impermeable bottom sheet. In this regard, the absorbent material forms at least a part of the absorbent core of the absorbent article. In one embodiment, the absorbent material is disposed within the fluid-permeable top sheet.

[0081] In one embodiment, the feminine hygiene product is selected from the group consisting of a panty liner, a sanitary napkin, a postpartum absorbent pad, a light incontinence pad, an interlabial pad, a disposable menstrual protection undergarment, and a tampon. In one embodiment, the feminine hygiene product is selected from the group consisting of a panty liner, a sanitary napkin, a postpartum absorbent pad, a light incontinence pad, an interlabial pad, and a disposable menstrual protection undergarment. In some embodiments, the absorbent article of the present disclosure is not in the form of a tampon. The feminine hygiene product can be manufactured by known methods (see, for example, U.S. Patent No. 9,717,817, which is hereby incorporated by reference in its entirety).

[0082] In one embodiment, the feminine hygiene product is configured to be worn externally. In one embodiment, the feminine hygiene product is not configured to be worn internally. In one embodiment, the absorbent article is a meat packaging pad. In one embodiment, the meat packaging pad is a fish meat packaging pad. The meat packaging pad may include those known in the art and can be manufactured by known methods (see U.S. Patent Nos. 5,908,649 and 7,655,829, which are hereby incorporated by reference in their entirety).

Examples

[0083] Example 1: Blocking of TMA Using Fluff Pulp Treated with Citric Acid The fluff pulp treated with citric acid (0.45 wt%) and the untreated fluff pulp were decomposed into fibers, formed into pads, placed in a sealed container, and infiltrated with a TMA solution. The untreated fluff pulp was from the same grinder as the fluff pulp treated with citric acid but did not include a buffering treatment.

[0084] The fluff pulp sheet was decomposed into fibers, and then the fluff pulp was formed into pads with a diameter of 5.08 cm (2 inches) with an average weight of 0.94 ± 0.02 g. These pads were compressed with a press at a pressure of 13.79 MPa (2000 psi).

[0085] The test containers were assembled from 500 mL water bottles, which were selected based on their compressibility. A 16-gauge needle was passed through the plastic lid of the water bottle, adhered in place, and sealed with silicone caulking. A rubber tube was placed around the hilt of the needle to allow for an airtight seal between the hilt and the measuring device.

[0086] The compressed fluff spheres were introduced into the test containers, infiltrated with 15 g of solution, sealed, and then, after 2 hours, the above headspace was tested for TMA. The TMA solutions were tested at four concentrations: 0.0005 wt%, 0.027 wt%, 0.034 wt%, and 0.05 wt%. Normal vaginal fluid not associated with bacterial vaginitis has a TMA level of 0.0005 wt% according to literature values.

[0087] [Table 1]

[0088] The concentration of TMA in the headspace of the containers was tested 2 hours after intrusion, on both the control and test pulps. A 105SE model Sensidyne® tube was used. These tubes are classified for use with ammonia (label), but can also be used with TMA. The actual TMA concentration is found by multiplying the Sensidyne® reading by a conversion factor of 0.5.

[0089] A total of 25 samples were tested: 11 untreated control fluff pulp samples and 14 test fluff pulp samples treated with citric acid. At least 2 samples per concentration were averaged. If the first 2 results varied, 3 or more samples per concentration were tested. Prior to measuring TMA in the gas headspace of the containers, the 25 samples were interacted with TMA intrusion for approximately 2 hours at 25 °C to ensure equilibration.

[0090] The TMA concentration in the headspace above the pads was compared for test fluff pulp treated with citric acid and untreated control fluff pulp. As summarized in Table 2 and Figure 1, fluff pulp treated with citric acid was found to reduce the headspace concentration of TMA in varying amounts. As shown, citric acid-treated fluff was found to eliminate TMA volatilization at 0.0005 wt%, the literature concentration in healthy vaginal fluid, and at 0.027 wt%, 60 times this concentration. At 0.034 wt%, 70 times the literature value, citric acid-treated fluff was found to reduce the volatilization of odorants into the headspace by an average of 95%. The ability of citric acid-treated fluff to steadily inhibit TMA volatilization into the headspace was not overwhelming up to 0.05 wt%, 100 times the TMA concentration found in healthy vaginal fluid. Even at this concentration, citric acid-treated fluff had an average headspace odorant level 71.1% less than untreated fluff.

[0091]

Table 2

[0092] In the 0.027% TMA solution, the average concentration of TMA in the headspace relative to the citric acid-treated fluff pad was 0.33 ppm. The untreated pulp had an average concentration of TMA in the headspace of 72 ppm. The citric acid-treated fluff reduced TMA in the headspace by 99.5%.

[0093] In the 0.034% TMA solution, the citric acid-treated fluff had an average concentration of TMA in the headspace of 5 ppm as read. The untreated pulp had an average TMA level of 100 ppm in the gas headspace. Note that the detection limit of the Sensidyne® tube is 100 ppm. Therefore, the actual average TMA level in the gas headspace may have been higher than 100 ppm. The citric acid-treated fluff reduced TMA by at least 95% at the headspace reading.

[0094] In the 0.05% solution, the citric acid-treated fluff had an average concentration of TMA in the headspace of 26.8 ppm as read. However, the readings for the citric acid-treated fluff were in the range of 10 - 51 ppm at this concentration. In contrast, the maximum variation between any two sample points at other concentrations was 7 ppm (between 68 ppm and 75 ppm for untreated pulp at 0.03%).

[0095] The TMA concentration in the headspace above the untreated fluff exceeded the maximum reading of the sensor for two of the three readings taken. Since it was not possible to know the exact concentration, these data were reported as a sensor reading of 100 ppm. Based on how quickly the sensor reached its maximum value, how far beyond the maximum the colorimetric readings stopped, and the foul odors encountered by the tester (TMA has a fishy odor at low concentrations and an ammonia-like odor at high concentrations), it is possible to estimate how much higher the actual concentration was than the maximum reading, but this is only an estimate. These observations were recorded in the test records.

[0096] For the purposes of the present disclosure, terms such as, for example, "upper", "lower", "vertical", "horizontal", "inward", "outward", "inner", "outer", "front", "rear", etc. are to be construed as descriptive and not limiting of the scope of the claimed subject matter. Further, the use of "including", "comprising", or "having" and variations thereof herein is meant to encompass the items listed thereafter and their equivalents as well as additional items. Unless otherwise specifically limited, the terms "connected", "coupled", and "mounted" and variations thereof herein are used broadly and encompass both direct and indirect connections, couplings, and mountings. The term "about" means plus or minus 5% of the stated value.

[0097] The principles, representative embodiments, and modes of operation of the present disclosure have been described in the foregoing description. However, the aspects of the present disclosure that are intended to be protected should not be construed as limited to the specific embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. It will be recognized that others may make modifications and variations without departing from the spirit of the present disclosure and that equivalents may be used. Accordingly, it is expressly intended that all such modifications, variations, and equivalents be included within the spirit and scope of the present disclosure as set forth in the claims.

[0098] [Aspects of the Invention] [1] A method for reducing free trimethylamine ("TMA"), comprising contacting TMA molecules with an absorbent material comprising a cellulose fiber matrix and a carboxylic acid linked to the cellulose fiber matrix, wherein the reduction of free TMA is a comparison with a control. [2] The method according to 1, wherein the TMA molecules are in a liquid. [3] The method according to 2, wherein the TMA molecules are in menstrual fluid. [4] The method according to 2, wherein the TMA molecules are in meat fluids. [5] The method according to 1, wherein the TMA molecules are in a gas. [6] The method according to 1, wherein the control is an empty control. [7] The method according to 1, wherein the control is a control of the absorbent material. [8] The method according to 1, wherein the cellulose fiber matrix comprises a cellulose pulp structure. [9] The method according to 1, wherein the cellulose fiber matrix comprises fibers selected from the group consisting of cellulose fibers and cellulose-based fibers.

[10] The method according to 9, wherein the cellulose-based fibers are selected from the group consisting of viscose fibers, modal fibers, lyocell fibers, and combinations thereof.

[11] The method according to 1, wherein the carboxylic acid is selected from the group consisting of malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, propionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof.

[12] The method according to claim 1, wherein the carboxylic acid is selected from the group consisting of citric acid, lactic acid, malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, propionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof.

[13] The method according to claim 1, wherein the carboxylic acid is citric acid or a salt thereof.

[14] The method according to any one of claims 1 to 13, wherein the absorbent material comprises a carboxylic acid content between about 0.01 wt% and about 10 wt%.

[15] The method according to claim 1, wherein the absorbent material contains 0.01 wt% citric acid, is introduced into a solution having about 0.034 wt% TMA, and the control is an equal amount of absorbent material consisting of southern bleached softwood kraft fluff pulp substantially free of any added carboxylic acid, and the cellulose fiber matrix can reduce free TMA by at least about 95 ppm in a headspace of about 0.5 L.

[16] The reduction of free TMA is contacting the absorbent material disposed in the container with an amount of TMA; withdrawing a portion of the gas headspace of the container; measuring the amount of free TMA in the withdrawn portion of the gas headspace; and determining the reduction of free TMA in the gas headspace by comparison with a control The method according to claim 15, measured by a process comprising

[17] The method according to claim 1, wherein the absorbent material contains 0.01 wt% citric acid, is introduced into a solution having about 0.027 wt% TMA, and the control is an equal amount of absorbent material consisting of southern bleached softwood kraft fluff pulp substantially free of any added carboxylic acid, and the cellulose fiber matrix can reduce free TMA by at least about 99% in a headspace of about 0.5 L.

[18] The method according to 1, wherein the absorbent material contains 0.01% by weight of citric acid, is introduced into a solution having about 0.05% by weight of TMA, and the control is the same amount of absorbent material consisting of southern bleached softwood kraft fluff pulp substantially free of any added carboxylic acid, and the cellulose fiber matrix can reduce free TMA by at least about 50% in a headspace of about 0.5 L.

[19] Reduction of free TMA is contacting the absorbent material disposed in the container with an amount of TMA; withdrawing a portion of the gas headspace of the container; measuring the amount of free TMA in the withdrawn portion of the gas headspace; and determining the reduction of free TMA in the gas headspace by comparison with a control The method according to 17 or 18, measured by a process comprising

[20] A method of sequestering TMA molecules, comprising contacting the TMA molecules with an absorbent material comprising a cellulose fiber matrix and a carboxylic acid linked to the cellulose fiber matrix.

[21] The method according to 20, wherein the TMA molecules are in a liquid.

[22] The method according to 21, wherein the TMA molecules are in menstrual fluid.

[23] The method according to 21, wherein the TMA molecules are in meat fluids.

[24] The method according to 20, wherein the TMA molecules are in a gas.

[25] The method according to 20, wherein the cellulose fiber matrix comprises a cellulose pulp structure.

[26] The method according to 20, wherein the cellulose fiber matrix comprises fibers selected from the group consisting of cellulose fibers and cellulose-based fibers.

[27] The method according to 26, wherein the cellulose-based fiber is selected from the group consisting of viscose fiber, modal fiber, lyocell fiber, and combinations thereof.

[28] The method according to 20, wherein the carboxylic acid is selected from the group consisting of malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, propionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof.

[29] The method according to 20, wherein the carboxylic acid is selected from the group consisting of citric acid, lactic acid, malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, propionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof.

[30] The method according to 20, wherein the carboxylic acid is citric acid or a salt thereof.

[31] The method according to any one of 20 to 30, wherein the absorbent material contains a carboxylic acid content between about 0.01% by weight and about 10% by weight.

[32] The method according to 20, wherein when the absorbent material contains 0.45% by weight of citric acid and TMA molecules are introduced into a solution of about 0.05% by weight, the cellulose fiber matrix can block the TMA molecules so that an equilibrium state of about 0.5 L of headspace contains less than about 50 ppm of free TMA.

[33] The method according to 20, wherein when the absorbent material contains 0.45% by weight of citric acid and TMA molecules are introduced into a solution of about 0.034% by weight, the cellulose fiber matrix can block the TMA molecules so that an equilibrium state of about 0.5 L of headspace contains less than about 10 ppm of free TMA.

[34] The method according to 20, wherein when the absorbent material contains 0.45% by weight of citric acid and TMA molecules are introduced into a solution of about 0.027% by weight, the cellulose fiber matrix can block the TMA molecules so that an equilibrium state of about 0.5 L of headspace contains less than about 5 ppm of free TMA.

[35] The amount of free TMA is contacting an absorbent material disposed in a container with a certain amount of TMA in a solution; withdrawing a portion of the gas headspace of the container; and measuring the amount of free TMA in the withdrawn portion of the gas headspace The method according to any one of items 32 to 34, measured by a process comprising

[36] An absorbent article comprising an absorbent material, the absorbent material comprising a fiber matrix and a carboxylic acid linked to the fiber matrix, the fiber matrix comprising fibers selected from the group consisting of cellulose fibers and cellulose-based fibers, and the absorbent article being a feminine hygiene product or a meat packaging pad.

[37] The absorbent article according to 36, wherein the absorbent material does not contain an organic silicone polymer binder linked to a carboxylic acid and the absorbent material does not contain an inorganic peroxide.

[38] The absorbent article according to 36, wherein the cellulose-based fibers are selected from the group consisting of viscose fibers, modal fibers, lyocell fibers, and combinations thereof.

[39] a fluid-permeable top sheet, and a fluid-impermeable bottom sheet The absorbent article according to 36, further comprising, wherein the absorbent material is disposed between the fluid-permeable top sheet and the fluid-impermeable bottom sheet.

[40] a fluid-permeable top sheet, and a fluid-impermeable bottom sheet The absorbent article according to 36, further comprising, wherein the absorbent material is disposed within the fluid-permeable top sheet.

[41] The absorbent article according to any one of 36 to 40, wherein the absorbent material forms at least a portion of the absorbent core of the absorbent article.

[42] The absorbent article according to any one of 36 to 41, further comprising a superabsorbent polymer.

[43] The absorbent article according to any one of items 36 to 42, wherein the carboxylic acid is a polycarboxylic acid.

[44] The absorbent article according to item 43, wherein the polycarboxylic acid is a partially or completely neutralized salt.

[45] The absorbent article according to any one of items 36 to 42, wherein the carboxylic acid is selected from the group consisting of malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, propionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof.

[46] The absorbent article according to any one of items 36 to 42, wherein the carboxylic acid is selected from the group consisting of citric acid, lactic acid, malic acid, tartaric acid, salicylic acid, succinic acid, formic acid, pyruvic acid, propionic acid, butyric acid, isobutyric acid, glycolic acid, salts thereof, and combinations thereof.

[47] The absorbent article according to any one of items 36 to 42, wherein the carboxylic acid is citric acid or a salt thereof.

[48] The absorbent article according to any one of items 36 to 47, wherein the absorbent material contains a carboxylic acid content between about 0.01% by weight and about 10% by weight.

[49] The absorbent article is a feminine hygiene product, and the feminine hygiene product is selected from the group consisting of panty liners, sanitary napkins, postpartum absorbent pads, light incontinence pads, interlabial pads, tampons, and disposable menstrual protection underwear, according to any one of items 36 to 48.

[50] The feminine hygiene product according to item 49, wherein the feminine hygiene product is configured to be worn externally.

[51] The feminine hygiene product according to item 49, wherein the feminine hygiene product is not configured to be worn internally.

[52] The absorbent article is a meat packaging pad, and the meat packaging pad is a fish packaging pad, according to any one of items 36 to 48.

[53] A method for measuring the reduction of free TMA blocked by an absorbent material, comprising: contacting the absorbent material disposed in a container with any amount of TMA; withdrawing a portion of the gas headspace of the container; measuring the amount of free TMA in the withdrawn portion of the gas headspace; and determining the reduction of free TMA in the gas headspace by comparison with a control. A method as described above.

[54] The method according to 53, wherein the absorbent material comprises a fiber matrix and a carboxylic acid linked to the fiber matrix.

[55] The method according to 53, wherein a portion of the headspace is withdrawn after free TMA has reached equilibrium.

[56] The method according to 53, wherein the control is an empty control.

[57] The method according to 53, wherein the control is a control of the absorbent material.

[58] Measuring the amount of free TMA in the withdrawn portion of the gas headspace comprises: passing the withdrawn portion of the gas headspace through a stationary phase loaded with a colorimetric analysis marker that changes color when contacted with TMA; and measuring the amount of color change in the stationary phase as the withdrawn portion of the gas headspace passes through the stationary phase. A method according to 53, including the above steps.

[59] A method for manufacturing an absorbent article, comprising: preparing an absorbent material comprising a fiber matrix and a carboxylic acid linked to the fiber matrix; and connecting a fluid-permeable top sheet and a fluid-impermeable bottom sheet to the absorbent material. A method as described above.

[60] The method according to 59, wherein the absorbent material is disposed between a fluid-permeable top sheet and a fluid-impermeable bottom sheet.

[61] The method according to claim 59, wherein the absorbent material is disposed within the fluid permeable top sheet.

[62] The method according to claim 59, wherein the absorbent article is a feminine hygiene product.

[63] The method according to claim 62, wherein the feminine hygiene product is selected from the group consisting of panty liners, sanitary napkins, postpartum absorbent pads, light incontinence pads, interlabial pads, and disposable menstrual panties.

[64] The method according to claim 62 or 63, wherein the feminine hygiene product is configured to be worn externally.

[65] The method according to any one of claims 62 to 64, wherein the feminine hygiene product is not configured to be worn internally.

[66] The method according to claim 59, wherein the absorbent article is a meat packaging pad.

[67] The method according to claim 59, wherein the absorbent article is the absorbent article according to any one of claims 36 to 52. Embodiments of the invention claiming exclusive properties or privileges are defined as follows.

Claims

**Claim 1** A method for reducing free trimethylamine (“TMA”), comprising contacting TMA molecules with an absorbent material comprising a cellulose fiber matrix and citric acid directly linked to the cellulose fiber matrix, wherein the absorbent material contains 0.01% by weight of citric acid, is placed in a closed container, and when the TMA molecules are introduced into a solution of 0.0005% to 0.034% by weight, the gas headspace of the closed container contains less than 50 ppm of free TMA in equilibrium. **Claim 2** The method according to claim 1, wherein the TMA molecules are in menstrual fluid. **Claim 3** The method according to claim 1, wherein the TMA molecules are in meat fluids. **Claim 4** The method according to claim 1, wherein the cellulose fiber matrix comprises a cellulose pulp structure. **Claim 5** The method according to claim 1, wherein the cellulose fiber matrix comprises fibers selected from the group consisting of cellulose fibers and cellulose-based fibers. **Claim 6** The method according to claim 5, wherein the cellulose-based fibers are selected from the group consisting of viscose fibers, modal fibers, lyocell fibers, and combinations thereof. **Claim 7** When the absorbent material comprising a cellulose fiber matrix and citric acid directly linked to the cellulose fiber matrix contains 0.01% by weight of citric acid, TMA is introduced into a 0.034% by weight solution, and the control is an equal amount of absorbent material consisting of untreated fluff pulp substantially free of any added carboxylic acid, the absorbent material can reduce free TMA by at least 95 ppm in a 0.5 L headspace. The method according to claim 1. **Claim 8** The reduction of free TMA is contacting the absorbent material placed in the container with an amount of TMA; withdrawing a portion of the gas headspace of the container; measuring the amount of free TMA in the withdrawn portion of the gas headspace; and determining the reduction of free TMA in the gas headspace by comparison with the control measured by a process comprising. The method according to claim 7. **Claim 9** The method according to claim 1, wherein when the absorbent material comprising a cellulose fiber matrix and citric acid directly linked to the cellulose fiber matrix contains 0.01% by weight of citric acid, is introduced into a solution of 0.027% by weight of TMA, and the control is an equal amount of absorbent material consisting of untreated fluff pulp substantially free of any added carboxylic acid, the absorbent material is capable of reducing free TMA by at least 99% in a 0.5 L headspace.

10. The method according to claim 1, wherein when the absorbent material comprising a cellulose fiber matrix and citric acid directly linked to the cellulose fiber matrix contains 0.01% by weight of citric acid, is introduced into a solution of 0.05% by weight of TMA, and the control is an equal amount of absorbent material consisting of untreated fluff pulp substantially free of any added carboxylic acid, the absorbent material is capable of reducing free TMA by at least 50% in a 0.5 L headspace.

11. The reduction of free TMA is contacting the absorbent material disposed in a container with an amount of TMA; withdrawing a portion of the gas headspace of the container; measuring the amount of free TMA in the withdrawn portion of the gas headspace; and determining the reduction of free TMA in the gas headspace as compared to the control by a process comprising: The method according to claim 9 or 10, measured by.

12. A method for measuring the reduction of free TMA sequestered by an absorbent material, comprising: contacting the absorbent material disposed in a container with an amount of TMA; withdrawing a portion of the gas headspace of the container; measuring the amount of free TMA in the withdrawn portion of the gas headspace; and determining the reduction of free TMA in the gas headspace as compared to a control, where the control is an empty control or the control is an equal amount of absorbent material consisting of untreated fluff pulp substantially free of any added carboxylic acid, comprising the absorbent material contains a fiber matrix and citric acid directly linked to the fiber matrix, when the absorbent material contains 0.01% by weight of citric acid, is disposed in a closed container, and TMA molecules are introduced into a solution of 0.0005% to 0.034% by weight, the gas headspace of the closed container contains less than 50 ppm of free TMA at equilibrium. method.

13. The method according to claim 12, wherein a part of the headspace is withdrawn after the free TMA has reached equilibrium.

14. measuring the amount of free TMA in the withdrawn part of the gas headspace by passing the withdrawn part of the gas headspace over a stationary phase loaded with a colorimetric analysis marker that changes color when in contact with TMA; and measuring the amount of discoloration in the stationary phase as the withdrawn part of the gas headspace passes over the stationary phase The method according to claim 12, comprising.

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