Substrates treated with solutions containing cyclodextrins for imparting odor control to materials used in absorbent products

Abstract

Solutions containing cyclodextrins for imparting odor control to materials used in absorbent products and related products and methods. The cyclodextrin-containing solution for imparting odor control to materials used in absorbent products contains an optional polar organic solvent, water, cyclodextrin, and one or more odor control compounds. The solution can be used to uniformly apply a homogeneous solution of a cyclodextrin complex to a solid surface, whereby the cyclodextrin complex is precipitated in situ on the solid surface. When hydrated with urine, the cyclodextrin complex precipitates deposited from these solutions quickly release odors that conceal the odors, and may deposit on a substrate more effectively than the cyclodextrin complex in solid form.

Description

Technical Field

[0001] The present disclosure relates to solutions containing cyclodextrins for imparting odor control to materials used in absorbent products, substrates treated with solutions containing cyclodextrins for imparting odor control to materials used in absorbent products, and related products and methods.

[0002] background

[0003] Absorbent products, such as adult incontinence pads, bladder control pads, diapers, pull-on pants, etc., should eliminate the odor of fresh urine within a short period of time. Such products are usually disposable products that are worn in public. Their users value odor protection to avoid any possibility of embarrassment. Although many commercially available products claim to provide some type of odor control, these commercially available products may not effectively control the odor of fresh urine at the moment the product is used. The odor of fresh urine at body temperature is usually easily detected on these absorbent products. It is especially noticeable in the urine of the elderly. Therefore, the industry still hopes for more effective odor control, especially in absorbent products.

[0004] Many attempts have been made to address the problems associated with controlling odor in absorbent products. Among the main approaches, odor control involves inhibiting the growth of odor-causing bacteria and adsorbing odorous molecules onto high surface area adsorbents. However, such conventional techniques are often too slow and / or ineffective in reducing fresh urine odor in a short period of time.

[0005] In another approach, cyclodextrins are used for odor control in absorbent products. For example, U.S. Pat. No. 5,429,628 discloses the use of free, uncomplexed cyclodextrins to effectively absorb malodors. U.S. Pat. No. 5,429,628 uses small particle size cyclodextrins to increase the surface area available for absorbing odorous molecules and thus improve the efficiency of odor absorption. U.S. Pat. No. 5,429,628 also teaches the formation of a perfume / cyclodextrin complex by combining perfume and cyclodextrin in a suitable solvent (such as water), or preferably, by kneading and / or pulping the ingredients together in the presence of a minimum amount of solvent (preferably water). The kneading / pulping method is particularly desirable because it produces a smaller solid particle size. After freeze drying or spray drying, the solid complex can be ground into particles having a particle size of less than about 10 μm. However, care must be taken during grinding to avoid generating workplace safety hazards of inhalable particles.

[0006] In addition, the use of aqueous odor absorbing solutions for odorous surfaces is also described, for example, in U.S. Pat. No. 6,284,231. The composition of the solution disclosed in U.S. Pat. No. 6,284,231 includes about 0.1% to about 20% dissolved, water-soluble, uncomplexed cyclodextrin, an effective amount of at least one ingredient for enhancing the odor absorbing properties of the cyclodextrin and a water-soluble antimicrobial active substance. These solutions are generally provided in a spray can and are available under the trade name Under commercialization.

[0007] Although conventional technology provides cyclodextrins that are generally useful for absorbing odors, it is not simple to incorporate fine dry particles of cyclodextrin complexes into absorbent products. Dry composite powders can be sprayed, mixed or dispensed onto absorbent products. However, in practice, these application methods are not satisfactory. The fixation of cyclodextrin / perfume complexes should not involve excess water to avoid premature release of perfume. Water-soluble adhesives have been disclosed, such as low melting temperature polymer adhesives, such as polyethylene glycol. Another disclosed method is to apply the cyclodextrin / perfume slurry directly to the absorbent product through a drying step. However, in practice, these slurries are difficult to handle, distribute and apply evenly.

[0008] In order to create a cyclodextrin complex in a low viscosity liquid form that can be more easily handled during the manufacture of absorbent articles and to avoid the sedimentation of insoluble cyclodextrin particles, U.S. Pat. No. 9,592,168 teaches an absorbent article comprising an inclusion complex of cyclodextrin and an organic compound, the inclusion complex being made using a colloidal grinding and spray drying process, wherein the inclusion complex is dispersed in a matrix comprising a polysiloxane oil. The creation of colloidal-sized dry particles allows the production of a uniform dispersion of solid particles for use in the manufacture of absorbent articles.

[0009] U.S. Patent No. 5,429,628 provides examples of applying cyclodextrin to Kraft cellulose fibers by dissolving the cyclodextrin in water at an elevated temperature to form a clear solution and spraying the solution onto the fibers. All examples require drying the aqueous carrier from the substrate by air or oven drying or freeze drying. The low solubility of cyclodextrin requires high solution additions to achieve effective performance levels, and the high moisture content of the solution requires drying the cellulose fibers to prevent microbial growth during storage. After drying, fluff pulp typically contains 6-8% water. If the moisture content increases to a range of about 13-15%, microorganisms can grow. Therefore, all of these examples are impractical without an additional drying step.

[0010] U.S. Patent No. 5,571,782 also teaches the use of an effective amount of a cyclodextrin / active complex in the form of solid particles having a particle size of less than about 12 μm for rapid release of the perfume active upon wetting. In fabric softener and solid detergent compositions, the handling of these solid particles is simple, but can be awkward and problematic when attempting to apply the solid particles to absorbent materials and / or absorbent products.

[0011] U.S. Patent Nos. 10183273 and 10427133 claim a layer of an absorbent article treated with a substituted cyclodextrin complex (i.e., degree of substitution = 0.4 to 2.5 R / glucose unit of cyclodextrin) and an odor-controlling organic compound in powder form or dispersed in a carrier to form a dispersion applied to the absorbent article. The carrier is silicone oil, mineral oil, petrolatum, polyethylene glycol and / or glycerol. U.S. Patent Nos. 10183273 and 10427133 also describe an application method using cyclodextrin and an odor-controlling organic compound in a volatile solvent system containing at least 60% water, alcohol, ketone or aldehyde, hydrocarbon or supercritical fluid. In some forms, the solution is easily pumped or sprayed directly onto the absorbent article. However, this method uses only substituted cyclodextrins, which are believed to be packed into a physical form after crystallization, which is superior to unsubstituted cyclodextrin in terms of rapid release of the odor-controlling compound complexed with the cyclodextrin.

[0012] U.S. Patent No. 8,574,683 teaches a method of making a pulp sheet of odor suppressing absorbent fibers comprising a cyclodextrin odor absorbent and a biocide dissolved in a non-aqueous liquid carrier consisting of less than 20% water and applied to a pulp sheet of cellulosic fibers. Many of the fragrances and essential oils included in this disclosure, such as citral, have been shown to have biocidal activity, including, for example, the following disclosures: K. Winska, et.al. “Essential Oils as Antimicrobial Agents—Myth or Real Alternative?” Molecules (2019) Jun; 24(11): 2130; C. Shi. et.al. “Antimicrobial Activity and Possible Mechanism of Action of Citral against Cronobacter sakazakii” PLoS One 2016; 11(7), and M, Choudhary, et.al. “Lemongrass Essential Oil Components with Antimicrobial and Anticancer Activities” Antioxidants 2021 Dec 22; 11(1): 20.

[0013] Despite the above applications and conventional techniques for reducing odor, a need exists for a convenient method of controlling the odor of fresh urine in absorbent products during use. That is, many previous odor control methods are too slow to reduce the odor of fresh urine in the product during use, and / or require additional processing, which can incur additional costs. The inventors have addressed the problems of conventional methods and provided a solution that effectively reduces the odor of fresh urine in a very short period of time. Users of these products value odor protection to avoid any chance of embarrassment. As discussed in detail below, the present disclosure provides methods for achieving these and other goals by making a solution containing a relatively high concentration of cyclodextrin complexes that can be easily sprayed onto materials used in absorbent products without the need for a drying step. When a drying step is not used, the moisture gain of the treated absorbent material should be <5 wt.%, or even <1 wt.%.

[0014] Brief description of the invention

[0015] In view of the foregoing exemplary problems with conventional and known cyclodextrin applications, the present application provides new and improved cyclodextrin-containing solutions for odor control of materials used in absorbent products.

[0016] One embodiment of the present application includes: a substrate comprising an odor control solution applied thereon, wherein the odor control solution comprises: water, cyclodextrin, an odor control compound, and optionally a polar organic solvent, wherein the substrate comprises: at least 0.2 kg of the odor control compound per 1000 kg of the substrate, and wherein, since the odor control solution has been applied to the substrate, the increase in the water content of the substrate is less than 2 wt.%.

[0017] In one embodiment of the aforementioned substrate, the odor control solution further comprises: a stabilizing additive.

[0018] In one embodiment of any of the preceding substrates, the odor control solution comprises: 1.5 moles to 6 moles of the odor control compound per mole of the cyclodextrin.

[0019] In one embodiment of any of the foregoing substrates, the pH of the odor control solution is greater than 9 and less than 12.5.

[0020] In one embodiment of any of the foregoing substrates, the odor control solution comprises: from about 6 wt.% to about 19 wt.% of the cyclodextrin and the odor control compound.

[0021] In any of the foregoing substrate embodiments, the odor control compound is selected from the group consisting of citral, coconut oil, d-limonene, octanol, and combinations thereof.

[0022] In one embodiment of any of the foregoing substrates, the moisture content of the substrate increases by less than 1.7 wt.% as a result of applying the odor control solution to the substrate.

[0023] In one embodiment of any of the foregoing substrates, the odor control solution comprises: 3.5 moles to 4.5 moles of the odor control compound per mole of the cyclodextrin, and the odor control solution is mixed at a temperature of 20° C. or higher prior to applying the odor control solution to the substrate to form a dispersion comprising a complex of the cyclodextrin and the odor control compound.

[0024] In one embodiment of any of the foregoing substrates, the odor control solution comprises: from about 0.1 wt. % to about 14 wt. % of a stabilizing additive.

[0025] In one embodiment of any of the foregoing substrates, the stabilizing additive is selected from the group consisting of corn syrup, glucose, high fructose corn syrup, trehalose, sucrose, sorbitol, amino acids, derivatives thereof, and combinations thereof.

[0026] In one embodiment of any of the foregoing substrates, the stabilizing additive is selected from the group consisting of corn syrup, glucose, high fructose corn syrup, derivatives thereof, and combinations thereof, and the odor control solution comprises: from about 2 wt.% to about 10 wt.% of the stabilizing additive.

[0027] In any of the foregoing substrate embodiments, the stabilizing additive is trehalose and the odor control solution comprises: from about 0.1 wt.% to about 1.0 wt.% of the stabilizing additive.

[0028] In one embodiment of any of the foregoing substrates, the odor control solution further comprises: glucose and / or corn syrup as a stabilizing additive, wherein the odor control solution comprises: about 2.4 wt.% to about 9.4 wt.% of the stabilizing additive, the odor control solution comprises: about 3.5 moles to about 6 moles of the odor control compound per mole of the cyclodextrin, the pH value of the odor control solution is greater than 9 and less than 12.5, the odor control compound is a mixture of compounds selected from the group consisting of: a mixture of citral and coconut oil, a mixture of d-limonene and coconut oil, a mixture of citral and d-limonene, and a mixture of octanol and d-limonene, and, before applying the odor control solution to the substrate, the odor control solution is mixed at a temperature of 20°C or higher to form a dispersion comprising a complex of the cyclodextrin and the odor control compound, and further, the increase in the moisture content of the substrate due to the application of the odor control solution to the substrate is less than 1.7 wt.%.

[0029] One embodiment of the present application includes an article, which includes the substrate of any of the above embodiments.

[0030] One embodiment of the present application includes a method for preparing an odor control substrate, comprising: a) providing a substrate, b) forming an odor control solution, the solution comprising: water, cyclodextrin, an odor control compound, a stabilizing additive and an optional polar organic solvent, wherein the odor control solution formed in b) is a dispersion comprising a complex of the cyclodextrin and the odor control compound, c) applying the odor control solution to the substrate to obtain the odor control substrate, wherein, after c), the odor control substrate comprises: at least 0.2 kg of the odor control compound per 1000 kg of the odor control substrate, and wherein the increase in the water content of the substrate due to the application of the odor control solution to the substrate is less than 1.7 wt.%.

[0031] Another embodiment of the present application includes: a substrate, comprising: the odor control solution applied thereon, wherein the odor control solution comprises: water, cyclodextrin, an odor control compound and a polar organic solvent, wherein the substrate comprises: at least 0.2 kg of the odor control compound per 1000 kg of the substrate.

[0032] In one embodiment of the aforementioned substrate, the moisture content thereof increases by less than 1 wt.% due to application of the odor control solution to the substrate.

[0033] In one embodiment of any of the aforementioned substrates, the substrate is fluff pulp in the form of compressed sheets or air-laid fibers, synthetic or cellulosic fiber spunbonded or carded nonwovens, woven fabrics or solid materials, or absorbent articles, wherein, when the substrate is a solid material, the solid material is selected from the group consisting of polymer foam, leather and plastic film, and wherein the substrate material is the absorbent article, and the absorbent article is an adult incontinence control pad, a feminine hygiene pad, a pull-up pants, an adult underwear, a baby diaper or a mattress.

[0034] In one embodiment of any of the foregoing substrates, the polar organic solvent is selected from the group consisting of glycerol, propylene glycol, polypropylene glycol, polyethylene glycol, and mixtures thereof.

[0035] In one embodiment of any of the foregoing substrates, the cyclodextrin is unsubstituted or substituted α-, β-, or γ-cyclodextrin.

[0036] In one embodiment of any of the foregoing substrates, the odor-controlling compound is an essential oil selected from the group consisting of citral, limonene, octanol, lavender, geranium, grapefruit, linalool, citronellol, linalyl acetate, geraniol, eugenol, floracetate, cardamom, eucalyptus, juniper berry, lavender, lemon verbena, lemongrass, patchouli, rose, spearmint, tea tree, oregano, persimmon, and mixtures thereof, a plant extract, an odor-controlling substance selected from the group consisting of benzaldehyde, cinnamaldehyde, privet aldehyde, anthocyanin aldehyde, and mixtures thereof, or an antibacterial substance selected from the group consisting of at least one of eucalyptus, lavender, thyme, mint, cajuput, cinnamon, clove, sage, tea tree oil, and mixtures thereof.

[0037] In one embodiment of any of the preceding substrates, the odor control solution comprises: 1.5 moles to 1.75 moles of the odor control compound per mole of the cyclodextrin.

[0038] In one embodiment of any of the foregoing substrates, the pH of the odor control solution is greater than or equal to 12.0.

[0039] One embodiment of the present application includes an article, which includes the substrate of any of the above embodiments.

[0040] One embodiment of the present application includes a method for preparing an odor control substrate, comprising: a) providing a substrate, b) applying an odor control solution to the substrate to obtain the odor control substrate, wherein the odor control solution comprises: a polar organic solvent, water, cyclodextrin and an odor control compound, wherein after b), the odor control substrate contains: at least 0.2 kg of the odor control compound per 1000 kg of the odor control substrate.

[0041] In one embodiment of the foregoing method, applying the odor control solution to the substrate in b) increases the moisture content of the substrate by less than 1 wt.%.

[0042] In one embodiment of any of the preceding methods, the odor control solution comprises: 1.5 moles to 1.75 moles of the odor control compound per mole of the cyclodextrin.

[0043] In one embodiment of any of the foregoing methods, the pH of the odor control solution is greater than or equal to 12.0.

[0044] Other objects, features and advantages of the present invention will become apparent to those skilled in the art in view of the following detailed description of the present invention and the accompanying drawings.

[0045] BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The figures provided herein illustrate some exemplary embodiments of solutions containing cyclodextrins for imparting odor control to materials used in absorbent products of the present application, which are described in detail below. The figures are merely exemplary and are not intended to limit the present invention.

[0047] Figure 1 is a graph showing dose and response of citral for urine odor control.

[0048] Figure 2 It is a micrograph at 20 times magnification, with a minimum scale of 100 μm, showing particles of citral / β-cyclodextrin complex precipitated from a glycerol / water solution at pH 12.5 at 86°C.

[0049] Figure 3 It is a micrograph at 20 times magnification, with a minimum scale of 100 μm, showing the precipitation of citral / β-cyclodextrin complex particles from a glycerol / water solution at 86°C, pH 9.6. DETAILED DESCRIPTION OF THE INVENTION

[0051] Solutions containing cyclodextrins for imparting odor control to materials used in absorbent products of the present application, as well as related products and methods, are now described with reference to embodiments. The description provided herein is not intended to limit the scope of the claims, but rather to illustrate the diversity covered by the present application. The embodiments will be described more fully below with reference to the accompanying drawings, in which like numerals represent like elements in several drawings, and example embodiments are shown therein. However, the embodiments of the claims may be embodied in many different forms and should not be construed as limiting the embodiments herein. The embodiments listed herein are non-limiting embodiments and are merely examples of other possible embodiments.

[0052] As described above, there is a need for a technology for absorbent products, such as adult incontinence pads, bladder control pads, and pull-up pants, to eliminate the odor of fresh urine in a short period of time. Since such products are typically disposable products worn in public, users value odor protection to avoid any possibility of embarrassment. Although many commercially available products claim to have some type of odor control, these products may not be effective in controlling the odor of fresh urine when used. The odor of fresh urine at body temperature can be easily detected on these absorbent products.

[0053] To address the problems of conventional techniques, the present disclosure uses fast-acting odor masking and odor control agents that can be incorporated into cyclodextrin complexes and precipitated on fluff fibers. The active ingredients are stable in the complexes, have a long shelf life, and are released only when the fibers are exposed to urine. Many essential oil fragrances and organic odor control agents can be used to prepare stable cyclodextrin complexes that are highly soluble in polar organic and aqueous solvent systems. These soluble complexes can be uniformly sprayed or otherwise applied to fluff fiber sheets. After cooling to room temperature, in-situ precipitation of the complexes on the fiber surface unexpectedly effectively utilizes the odor masking agent and provides excellent odor control when the fiber is hydrated with urine. Therefore, the present disclosure relates to a novel solution applied in a specific addition amount, which has: (1) an optimal essential oil to cyclodextrin molar ratio and solution pH; (2) a sufficient concentration of soluble cyclodextrin complexes to provide urine odor control when applied to materials used in absorbent products; and (3) a sufficiently low concentration of water so that no additional drying step is required after application.

[0054] Cyclodextrins are cyclic oligosaccharides containing 6 to 12 glucose units that can form inclusion complexes with host molecules, which can be fully or partially embedded in the cyclodextrin cavity. Inclusion complexes composed of highly volatile essential oils and other odor control ingredients can be deposited on the surface of a substrate in a stable dry form. A stable, dry form is needed because volatile essential oils are expensive ingredients in formulations and should not evaporate from the treated substrate. The odor of the host molecules, especially the essential oils, can be released by the action of water and urine. The present disclosure relates to a solution whose composition, pH and temperature are conducive to the preparation of a soluble complex composed of cyclodextrin and essential oils or odor control compounds, so that the solution containing the soluble complex can be sprayed or otherwise applied to a material used in an absorbent product, so that the complex is precipitated in situ on the surface of the material when cooled to room temperature, and the material treated with the complex reduces the odor of body fluids (such as urine, menstruation and sweat).

[0055] Cyclodextrin complexes containing cyclodextrin and odor control compounds tend to have low water solubility and are difficult to be uniformly applied to and retained on the surface of solid fibers or films. At high pH and temperature, a solution containing a polar organic solvent and water provides the ability to form a cyclodextrin complex in solution and also provides the solubility required to uniformly apply a uniform solution of the cyclodextrin complex to a solid surface. After cooling to room temperature, the cyclodextrin complex is precipitated in situ on the surface of the solid fiber. Since the cyclodextrin complex is precipitated in situ on the surface of the solid fiber, particle size control is also not required. Generally speaking, the complex is formed by mixing or kneading the odor control compound and cyclodextrin together in the presence of a small amount of water. After freeze drying or spray drying, the complex is ground to a particle size of less than about 10 μm. Since the solution of the present disclosure utilizes in situ precipitation, such a process is not required. In addition, when preparing and applying the complex, colloid stability is not required. Therefore, the cyclodextrin complex can be easily prepared and applied to absorbent materials and cellulosic materials, even without a drying step.

[0056] Solutions containing cyclodextrins for imparting odor control

[0057] The odor control solution of the present disclosure may comprise: water, cyclodextrin, an odor control compound, and optionally a polar organic solvent.

[0058] In certain embodiments, polar organic solvents may be excluded from the odor control solution, however, in other embodiments, polar organic solvents may be included in the odor control solution. In embodiments where polar organic solvents are excluded from the odor control solution, the odor control solution may be primarily water. For example, the amount of water may be in the range of 82 wt.% to 93 wt.% relative to the total weight of the odor control solution. In certain embodiments, the water may be in the range of 75 wt.% to 95 wt.%, 80 wt.% to 95 wt.%, 80 wt.% to 90 wt.%, 82 wt.% to 93 wt.%, or about 85 wt.% relative to the total weight of the odor control solution. In embodiments including a polar organic solvent, the amount of the polar organic solvent can be in the range of 4 wt.% to 10 wt.%, 5 wt.% to 8 wt.%, or about 6 wt.% to about 7 wt.%, and the amount of water can be in the range of 5 wt.% to 15 wt.%, 8 wt.% to 13 wt.%, or about 11 wt.% to about 12 wt.%, relative to the total weight of the odor control solution.

[0059] The polar organic solvent can be any polar organic solvent that can provide the ability to form a cyclodextrin complex in solution, and can also provide the solubility required for uniformly applying a uniform solution of the cyclodextrin complex to a solid surface. Examples of acceptable polar organic solvents include, but are not limited to, glycerol, propylene glycol, polypropylene glycol, polyethylene glycol, and mixtures thereof. In particular, glycerol can be used as a polar organic solvent. The increase in the amount of polar organic solvent in the solution can improve the solubility of the cyclodextrin complex in the solution. For example, the solubility of the complex can be increased so that an effective amount of the complex can be applied to a substrate without excessively increasing moisture. Table 1 below shows the increase in the moisture content of the substrate at two levels of addition (i.e., 0.4 kg of essential oil / ADMT fluff pulp and 2.0 kg of essential oil / AMDT fluff pulp) as a function of glycerol concentration.

[0060] [Table 1]

[0061]

[0062] At higher addition levels of 2.0 kg citral / ADMT fluff pulp, as shown in 5 and 6 in Table 1, it was not possible to keep the moisture increase below 1% for glycerol solution fractions well below 85%. In other embodiments, a 100% water carrier was used, as shown in 3 and 6 in Table 1. This made it possible to prepare a 100% aqueous solution with a relatively high concentration of β-cyclodextrin at pH 12.5. In this case when the concentration of the complex was at or below about 19.7%, a fine, sprayable dispersion could be formed after adding 1.5 moles of citral per mole of β-cyclodextrin. At higher concentrations of the complex, a coarse dispersion was formed. This coarse dispersion settled within a few minutes and was difficult to spray onto a substrate.

[0063] Cyclodextrin can be any cyclodextrin that can form cyclodextrin complex with odor control compound.In certain embodiments, cyclodextrin is cyclodextrin comprising 6 to 12 glucose units.For example, cyclodextrin comprising 6 to 12 glucose units can form inclusion complex with many essential oils and odor control ingredients, wherein essential oils and odor control ingredients can be released by the effect of water and urine.The example of acceptable cyclodextrin includes but is not limited to commercially available unsubstituted cyclodextrin (i.e. α-, β- and γ-cyclodextrin).α-cyclodextrin comprises 6 glucose units.β-cyclodextrin comprises 7 glucose units.Cyclodextrin comprises 8 glucose units.Especially, β-cyclodextrin can be used because β-cyclodextrin has the cost performance that can be used for most absorbent products.

[0064] As described above, the odor control solution can form a cyclodextrin complex in a solution with an odor control compound. Unsubstituted cyclodextrin can be used to prepare such a complex. Generally speaking, three unsubstituted cyclodextrins (i.e., α-, β-, and γ-cyclodextrin) are commercially available. Among these commercially available unsubstituted cyclodextrins, β-cyclodextrin has an acceptable cost-effectiveness for most absorbent products. The solubility of β-cyclodextrin in water at about 20°C is only 1.8g / 100ml water. However, at 20°C at a pH of 12.5, the solubility of β-cyclodextrin can be increased to 75g / ml (pKa=12.2). At 20°C, the solubility of β-cyclodextrin in glycerol is 4.3g / 100ml. As shown in Table 2, in an 85% / 15% glycerol / water solution, at elevated pH and temperature, the solubility of β-cyclodextrin and β-cyclodextrin / citral complexes is about 21.6g / 100g solution or higher. Solutions can also be made with propylene glycol. The solubility of β-cyclodextrin in propylene glycol is greater than that in glycerol. Therefore, the solubility of cyclodextrin and their complexes can be increased by using polar organic solvent / water solution, increasing solution temperature and increasing pH.

[0065] [Table 2]

[0066]

[0067] Furthermore, even though the substituted cyclodextrins are more water soluble than the unsubstituted cyclodextrins, the performance of the unsubstituted cyclodextrins is still very good. The unsubstituted cyclodextrins can also be formulated into relatively high concentration solutions. Therefore, the unsubstituted cyclodextrins can be used in the present solutions.

[0068] The odor control compound can be any odor control compound that can provide odor control and / or odor masking. Examples of acceptable odor control compounds include, but are not limited to, essential oils (e.g., citral, limonene, d-limonene, lavender, geranium, persimmon, lemon, grapefruit, linalool, citronellol, linalyl acetate, geraniol, eugenol, fluoroacetate, cardamom, eucalyptus, juniper berry, lavender, lemon verbena, lemongrass, patchouli, rose, spearmint, tea tree, oregano, and mixtures thereof), plant extracts (e.g., Actifyte from Lubrizol), TM ), odor control substances (such as benzaldehyde, cinnamaldehyde, privetaldehyde, anthocyanin and their mixtures), antibacterial substances (such as eucalyptus, lavender, thyme, mint, eucalyptus, cinnamon, clove, sage, tea tree oil), and fragrances (such as coconut oil), and their mixtures. In particular, citral (i.e., C 10 H 16 O) can be used as an odor control compound. Citral is an essential oil with a strong lemongrass smell that can effectively control and / or mask the odor of urine. Other fragrant essential oils (particularly limonene and persimmon), reactive aldehydes (particularly benzaldehyde), sulfur-reducing compounds (particularly anthocyanin and privet aldehyde), and fatty alcohols (such as octanol) can be effective alone or in combination. In certain embodiments, the odor control compound is a mixture of compounds selected from the group consisting of a mixture of citral and coconut oil, a mixture of d-limonene and coconut oil, a mixture of citral and d-limonene, and a mixture of octanol and d-limonene.

[0069] The combined amount of cyclodextrin and odor control compound in the solution is limited by the solubility of the complex formed and is generally in the range of about 22 wt.% or less for a glycerol / water solution in a ratio of about 85 / 15. In certain embodiments, the amount of β-cyclodextrin / citral complex in the solution may be 15 wt.% to 22 wt.%, 20 wt.% to 23 wt.%, and / or about 21 wt.%. In other embodiments, i.e., for a 100% aqueous solution, when a fine precipitate is formed upon addition of citral to the β-cyclodextrin / water solution, the concentration of the complex may be lower, such as in the range of about 14 wt.% or less or even 13.8 wt.% or less. In certain embodiments, the concentration of cyclodextrin and odor control compound in the odor control solution is in the range of about 6.4 wt.% to 13.8 wt.%. The concentration range of cyclodextrin and odor control compound in the odor control solution can be 20 wt.%, 18 wt.%, 16 wt.%, 14 wt.%, 12 wt.%, 10 wt.%, 8 wt.%, or 6 wt.% on the upper limit and 1 wt.%, 2 wt.%, 3 wt.%, 4 wt.%, 5 wt.%, 6 wt.%, 7 wt.%, or 8 wt.% on the lower limit. In certain embodiments, the odor control solution comprises about 6 wt.% to about 19 wt.% of cyclodextrin, the odor control compound or the odor control solution comprises about 6.4 wt.% to about 18.2 wt.% of cyclodextrin and odor control compound. In other embodiments, the odor control solution comprises about 8 wt.% to about 9 wt.% of cyclodextrin and odor control compound. At higher concentrations, such as concentrations exceeding 20 wt.%, undesirable coarse precipitates may be formed.

[0070] The solution concentration of the complex is important in reducing solution addition to keep the moisture gain of the substrate below about 2 wt.%, below about 1.7 wt.%, less than about 1.3 wt.%, and / or below about 1 wt.%. However, the ratio of the odor control compound to the cyclodextrin is also important to impart good odor control properties to the substrate. For citral, the optimal molar ratio of citral to β-cyclodextrin is about 1.5-1.75 moles of citral to 1.0 mole of β-cyclodextrin. When the molar ratio is about 1:1 or less, the odor control performance is greatly reduced (with equal additions of citral). When the molar ratio is 1.75:1 or higher, the volatile, uncomplexed citral imparts unwanted color and odor to the substrate containing a solution of about 85% glycerol. For solutions without polar organic solvents, EO (essential oil): CD (cyclodextrin) molar ratios in the range of 4 to 6 allow mixing at 50°C, and molar ratios in the range of 4 to 6 allow mixing at 20°C with added corn syrup. In general, the molar ratio of the odor control compound to the cyclodextrin can be, for example, 2.5:1, 2.25:1, 2.0:1, 1.75:1, 1.5:1, 1.4, 1.3, 1.2, 1.1, and 1.0. In certain embodiments, the molar ratio of the odor control compound to the cyclodextrin can be 6.0:1, 5.5:1, 5.0:1, 4.5:1, 4.0:1, 3.5:1, and 3.0:1. Also, in certain embodiments, the odor control solution comprises: 1.5 moles to 6 moles of the odor control compound per mole of cyclodextrin. In other embodiments, the odor control solution comprises: 3.5 moles to 4.5 moles of the odor control compound per mole of cyclodextrin. Increasing the molar ratio of the odor control compound to the cyclodextrin can improve commercial processing by allowing a lower solution mixing pH and a lower mixing temperature, especially but not limited to for solutions that are primarily water-based.

[0071] The higher molar ratio of citral to β-cyclodextrin allowed for reduced use of glycerol and β-cyclodextrin to achieve the target addition of citral (kg citral / air-dried metric ton of fluff). It also reduced the moisture gain of the fluff pulp as shown in Table 3 below. The molecular weights of β-cyclodextrin and citral were 1135 g / mol (dry) and 152 g / mol, respectively. Actiphytes TM and other more concentrated plant essences can load β-cyclodextrin with higher levels of odor-controlling compounds.

[0072] [Table 3]

[0073]

[0074] In addition, commercially available complexes, such as citral / β-cyclodextrin complex (Wacker Chemical, W7 citral complex), can be used to give good odor control properties to fluff pulp in a solution containing a polar organic solvent. It is believed that the commercially available complex has a minimum citral content of 8.5 wt.%, which indicates a minimum citral to β-cyclodextrin molar ratio of 0.7:1. The target value of the citral: β-cyclodextrin molar ratio is unknown, but may be in the range of 1.0:1. The odor control solution may have a pH greater than or equal to 12.5, 12, 11, 10 or 9.6. At a pH below about 12, the odor control performance is greatly reduced. In certain embodiments, the pH is about 12.5. Further reducing the pH to 11 or even lower to pH 10 improves the convenience of commercial processing. In certain embodiments, the pH of the odor control solution is greater than pH 9.6 and less than 12.5, greater than 9 and less than 12.5, or greater than pH 10 and less than 11. However, such commercially available complexes have extremely high costs, which makes their implementation cost-prohibitive and impractical on a commercial scale.

[0075] The odor control solution may also optionally include a stabilizing additive. The stabilizing additive can help to disrupt the precipitation and crystallization of the dispersed complex of the cyclodextrin and odor control compound. In particular, in certain embodiments, the molar ratio of the water-based solution is increased to reduce the solution concentration, and the sample is prepared at 50°C and pH 12.5. As shown in the embodiment of Example 14, the stabilizing additive allows such a high molar ratio solution to be prepared at 20°C and pH 7. The reduced mixing temperature and pH allow simple commercial processing and have excellent odor control performance. Examples of acceptable stabilizing additives include, but are not limited to, corn syrup, glucose, high fructose corn syrup, trehalose, stable osmotic pressure substances including sucrose, sorbitol, amino acids and their derivatives, and mixtures thereof. The odor control solution may contain about 0.1wt.% to about 14wt.% of a stabilizing additive, about 4wt.% to about 14wt.% of a stabilizing additive, about 4wt.% to about 10wt.% of a stability additive, about 0.1wt.% to about 1.0wt.%, or even 2.4wt.% to 9.4wt.%. In certain embodiments, the additive that provides stabilization for the dispersion is corn syrup, glucose or high fructose corn syrup at a solution concentration of about 2 wt.% to 10 wt.% or even 6.2 wt.% to 9.4 wt.%. In other embodiments, the additive that provides stabilization for the dispersion is trehalose at a solution concentration of about 0.1 wt.% to 1.0 wt.%. In yet further embodiments, the additive that provides stabilization for the dispersion is selected from the group consisting of protective or osmotic pressure stabilizing substances (including sucrose, sorbitol, amino acids, and their derivatives).

[0076] The odor control solution described herein allows the cyclodextrin complex to be deposited aggressively from the odor control solution and quickly releases the odor masking odor when hydrated with urine. Typical odor control compounds are aromatic essential oils, which are released from the cyclodextrin complex when the treated fiber or film surface is hydrated. The odor control solution disclosed herein can give odor control to materials used in absorbent products. The odor control solution uses fast-acting odor masking and odor control agents, such as odor control compounds, which can be incorporated into the cyclodextrin complex and deposited on the fluff fibers. These fluff fibers, also known as cellulose fluff pulp, can be used as absorbent filling materials for absorption, such as diapers, mattresses, etc. Active ingredients (i.e., odor control compounds) can be stabilized in the cyclodextrin complex to extend the shelf life and are released only when the fiber contacts urine. Essential oil fragrances and organic odor control agents can be used to prepare stable cyclodextrin complexes, which are highly soluble in polar organic and water solvent systems. These soluble complexes can be evenly sprayed or otherwise applied to the fluff fiber sheet. After cooling to room temperature, the cyclodextrin complex is precipitated in situ on the fiber surface, providing unexpectedly effective utilization of the odor masking agent and delivering excellent odor control when the fiber is hydrated with urine. The odor control solution of the present disclosure has: (1) a sufficient concentration of cyclodextrin complex to give urine odor control when applied to materials used in absorbent products; and (2) the amount of added water is low enough so that no additional drying step is required after its application.

[0077] The odor control solution for imparting odor control to materials used in absorbent products of the present disclosure may comprise an optional polar organic solvent, water, cyclodextrin, and one or more odor control compounds. The cyclodextrin complex comprising cyclodextrin and the odor control compound has low water solubility and is difficult to apply and retain uniformly on the surface of a solid fiber or film. The solution consisting of a polar organic solvent and water at high pH and temperature provides the ability to form a cyclodextrin complex in solution. Such an odor control solution also provides the solubility and solution stability required to uniformly apply a uniform solution of the cyclodextrin complex to a solid surface.

[0078] A substrate having an odor control solution applied thereto

[0079] The substrate of the present disclosure includes an odor control solution applied thereto. The odor control solution is described in detail above, the discussion of which is incorporated herein by reference.

[0080] The substrate comprises: at least 0.2 kg of odor control compound per 1000 kg of substrate. In certain embodiments, the substrate comprises: at least 0.3 kg of odor control compound per 1000 kg of substrate. In other embodiments, the substrate comprises: at least 0.6 kg, 0.8 kg, 1 kg, 1.5 kg, or 2 kg of odor control compound per 1000 kg of substrate.

[0081] In addition, the increase in moisture content of the substrate due to the odor control solution applied thereto can be less than 2 wt.%. In certain embodiments, the increase in moisture content can be less than 2 wt.%, such as 1.6 wt.%, 1.3 wt.%, 1 wt.%, etc., as discussed in the present disclosure. That is, even after applying a sufficient amount of the odor control solution to achieve at least 0.2 kg of odor control compound per 1000 kg of substrate, the increase in moisture content of the substrate can still be less than 2 wt.%, as measured by comparing the weight of the substrate before and after the application of the odor control solution.

[0082] The odor control solution discussed above provides a cyclodextrin complex comprising cyclodextrin and an odor control compound. By utilizing a polar organic solvent and water at high pH and temperature, the cyclodextrin complex can be provided in a uniform solution and applied to a substrate. After cooling to room temperature, the cyclodextrin complex is precipitated in situ on the substrate, but there is no significant increase in the moisture content of the substrate. In addition, in certain embodiments, the cyclodextrin complex can be dispersed in an odor control solution in the absence of a polar organic solvent to be applied to a substrate. In certain embodiments, the moisture content of the substrate may increase by less than 0.8 wt.% due to the odor control solution applied thereto. In certain embodiments, the moisture content of the substrate may increase by less than 5 wt.%, 4 wt.%, 3 wt.%, 2 wt.%, 1.7 wt.%, 1.6 wt.%, 0.6 wt.%, 0.4 wt.%, 0.2 wt.%, 0.13 wt.%, or 0.1 wt.%. In certain embodiments, the odor control solution may comprise 67 wt.% glycerol as a polar organic solvent, 12 wt.% water, and 21 wt.% cyclodextrin and an odor control compound, wherein the cyclodextrin is unsubstituted β-cyclodextrin, and wherein the odor control compound is citral, wherein the citral and unsubstituted β-cyclodextrin are present in a molar ratio of 1.5 moles of citral per mole of unsubstituted β-cyclodextrin, wherein the substrate is fluff pulp, wherein the substrate comprises: 0.4 kg of citral per 1000 kg of fluff pulp, and wherein the moisture content of the substrate increases by less than 0.13 wt.% due to the odor control solution applied thereto. In certain embodiments, an odor control solution can be made without polar organic solvents, 85 wt.% water and 8 wt.% cyclodextrin and an odor control compound, wherein the cyclodextrin is unsubstituted β-cyclodextrin, and wherein the odor control compound is an equimolar mixture of d-limonene and octanol, wherein the odor control compound and unsubstituted β-cyclodextrin are present in a molar ratio of 4.0 total moles of the odor control compound per mole of unsubstituted β-cyclodextrin, wherein the substrate is fluff pulp, wherein the substrate comprises: 0.51 kg of the odor control compound per 1000 kg of fluff pulp, and wherein the moisture content of the substrate increases by less than 1.7 wt.% due to the odor control solution applied thereto. Limiting the moisture content of the substrate to less than about 2 wt.% has significant practical economic value. Adding a drying step to a typical fluff pulp machine would require $30 to $40 million in capital. Therefore, it is desirable to reduce the moisture content as much as possible.

[0083] The substrate is not limited to any specific substrate material. For example, the substrate can be fluff pulp in the form of compressed sheets or air-laid fibers, synthetic or cellulosic fiber spunbond or carded nonwovens, woven fabrics, solid materials, or absorbent articles. When the substrate is a solid material, the solid material is selected from the group consisting of polymer foams, leather, and plastic films. When the substrate is an absorbent article, the absorbent article is an adult incontinence control pad, a feminine hygiene pad, a pull-up pants, an adult underpants, a baby diaper, or a mattress.

[0084] Article comprising a substrate having an odor control solution applied thereto

[0085] The articles of the present disclosure include the above-mentioned substrates, the discussion of which is incorporated herein by reference. The articles are not limited, but may include, for example, articles that would benefit from the improved odor control achieved by the present disclosure. For example, such articles may include absorbent articles such as adult incontinence control pads, feminine hygiene pads, pull-on pants, adult underwear, baby diapers, or mattresses. Other substrates include, but are not limited to, fluff pulp in the form of compressed sheets or air-laid fibers, synthetic or cellulosic fiber spunbond or carded nonwovens, woven fabrics, or solid materials such as polymer foams, leather, or plastic films.

[0086] Method for preparing odor control substrate

[0087] The odor control substrate can be prepared by providing a substrate, and applying an odor control solution to the substrate to obtain an odor control substrate. The substrate and the odor control solution are described in detail above, the discussion of which is incorporated herein by reference.

[0088] The method may also include: forming an odor control solution, the odor control solution comprising water, cyclodextrin, an odor control compound, a stabilizing additive, and an optional polar organic solvent. The odor control solution prepared in the method may form a dispersion comprising a complex of cyclodextrin and an odor control compound. Because the dispersion is temporarily stable, the odor control solution comprising the dispersion may be applied to a substrate before the dispersion becomes unstable. When different compounds are used in the odor control solution, the formation of the dispersion may occur at different temperatures and pHs. For example, when the stabilizing additive is corn syrup, the odor control solution may be prepared at room temperature (ie, about 20° C.) and a pH greater than 9. When preparing an odor control solution without corn syrup, the odor control solution may be prepared at a temperature greater than 50° C. and a pH greater than 10.9. In certain embodiments, the odor control solution is prepared by mixing water and a stabilizing additive (eg, corn syrup) and then adjusting the pH of the mixture. The mixture may then be heated to a desired temperature (eg, a temperature greater than 50° C. or maintained at room temperature (ie, about 20° C.)). The cyclodextrin and the odor control compound may then be added to the mixture. The mixture can then be applied to a substrate.

[0089] As discussed above, mixing of certain embodiments of the odor control solution can be performed at a temperature of about 50° C. or above to produce a dispersion of the cyclodextrin and the odor control compound. However, in certain embodiments, mixing can be performed at room temperature (i.e., about 20° C.). In addition, the pH of the odor control solution can be reduced to, for example, 11.5, 11.0, 10.5, 10, 9.5, or 9. For example, the pH can be in the range of 9 to 12.5. Even with a higher molar ratio of the odor control compound to the cyclodextrin (e.g., a citral to cyclodextrin molar ratio of 4.0 or more), the reduced temperature and pH of the odor control solution individually and collectively ease commercial processing. The dispersibility of the odor control compound to the cyclodextrin at a higher molar ratio is unexpected and allows for increased odor control performance. Adding a stabilizing additive (e.g., corn syrup) also disrupts precipitation and crystallization of the dispersed cyclodextrin complex and reduces the instability of the dispersion. The stabilizing additive (e.g., smaller glucose molecules) is believed to interact with the outer surface of the chemically similar β-cyclodextrin complex to reduce the rate and amount of crystallization and / or precipitation of the complex. Thus, the stabilizing additive even further improves the performance of the odor control solution while avoiding an undesirable increase in moisture content in the fluff pulp (i.e., keeping the moisture increase less than 2 wt.%).

[0090] In certain embodiments, the odor control solution can be applied to the substrate at an elevated temperature and pH. By "elevated temperature," the present disclosure means a temperature above room temperature. For example, the odor control solution can be applied to the substrate at an elevated temperature of 70° C. to 90° C. In certain embodiments, the odor control solution can be applied to the substrate at an elevated temperature of 75° C. to 90° C., 80° C. to 90° C., or 83° C. to 86° C.

[0091] In one exemplary embodiment, the fluff pulp is untreated southern pine Kraft pulp sold under the trade name Sold by JLDE from Rayonier Advanced Materials. A warm solution containing citral was sprayed onto the fluff pulp at a solution addition rate of about 0.055 g of odor control solution per gram of fluff. The sheet was not dried after application of the odor control solution. The citral addition rate was calculated to be 2.0 kg of citral per air-dried metric ton of fluff. The moisture content of the fluff pulp increased by 0.65%, from 8% moisture content to 8.65% moisture content. It is beneficial to keep the moisture increase at a level of less than 5% or even less than 1%.

[0092] The complexing of citral with β-cyclodextrin reduces the evaporation of citral when drying, but when the complex is hydrated with water, the odor of citral can be released. The exemplary embodiment has no detectable odor when dry, but immediately releases a noticeable lemon odor when hydrated with only 2.5 g of water per gram of fluff. In addition, the exemplary embodiment effectively masks the odor of warm urine (at 35°C-40°C) using 2.5 g of urine per gram of fluff to 10 g of urine per gram of fluff.

[0093] Other advantages of fluff pulp through solutions

[0094] Glycerin used in the solution formulation can impart additional benefits to the fluff pulp, such as reduced compressibility of flaky Mullen and fiberized fluff pulp.

[0095] For example, at 80°C, One side of the pulp is sprayed with a solution of 85 wt.% glycerol and 15 wt.% water at 0.08 g solution / g pulp (the solution consists of 85 wt.% glycerol and 15 wt.% water), causing the Mullen to drop from an average value of 1472 kPa to 1107 kPa. Burst resistance (or Mullen) refers to the hydrostatic pressure applied at a controlled rate to produce the rupture of a conditioned test specimen. To obtain a measurement of burst resistance (or Mullen), pressure is applied at a controlled rate to a circular area of ​​a test specimen with a diameter of 30.48 mm (1.20 inches) through a rubber diaphragm. The material being tested is initially flat and firmly fixed on the circumference of the test location. As pressure is increased, the sample will expand freely and eventually burst. Burst resistance (or Mullen) is recorded as the pressure at rupture, in kPa.

[0096] Similar treatments were found to improve the mechanical properties of fluff pulp airlaid sheets. The mechanical properties associated with softness and feel are KES shear modulus and compression energy. In a fluff pulp with a basis weight of 400 g / sm and a density of 0.37 g / cc, the shear modulus was reduced by 20% and the compression energy was reduced by 29%. These values ​​indicate that the airlaid core of OCF (Odor Control Fiber, odor control fiber) can be considered softer than untreated fluff pulp. The Kawabata Evaluation System (KES) is used to objectively measure hand properties. The KES instrument measures mechanical properties corresponding to the basic deformation of the fabric during hand manipulation under low applied forces. The samples were conditioned and tested under laboratory atmospheric conditions of 21°C ± 2°C and 65% ± 5% relative humidity. The sample width was 20 cm. There were three replicates for shear stiffness. In the shear test, the KES-FB1 tensile shear tester applied opposite and parallel forces to the sample until a maximum deviation angle of 0.5° was reached. A pre-tension load of 50 gf / cm was applied. Lower shear stiffness values ​​(gf / cm*degrees) indicate less resistance to shear motion corresponding to softer materials. Example

[0097] The features and advantages of solutions containing cyclodextrins for imparting odor control to materials used in absorbent products and related products and methods are more fully demonstrated with respect to the following illustrative examples and embodiments.

[0098] Example 1 :Preparation of cyclodextrin complexes in solution

[0099] In the following examples, β-cyclodextrin was obtained from Acros Organics (CAS: 7585-39-9) and Wacker Chemie under the trade name W7. Citral is a volatile lemongrass-scented essential oil obtained from Perfumer's Apprentice (CAS: 5392-40-5).

[0100] A solution was prepared by first mixing 85 wt.% glycerol and 15 wt.% water and increasing its pH to 12.5 with sodium hydroxide. 50 g of this mixture was heated after pH adjustment. At about 75°C, 11.5 g of β-cyclodextrin was added. Heating and stirring were continued until the β-cyclodextrin was completely dissolved at about 86°C. At this point, 2.3 g of citral was added (using a molar ratio of 1.5 moles of citral / mole of β-cyclodextrin), and stirring was continued for a few minutes until a clear, water-white solution was obtained. The solution contained: 21.6 g of β-cyclodextrin and citral per 100 g of solution, 66.7 g of glycerol per 100 g of solution, and 11.8 g of water per 100 g of solution. The water content of β-cyclodextrin (up to 10 wt.%) was not taken into account in these calculations.

[0101] Example 2 :pH determination

[0102] In the following examples, untreated The pH of the fluff was compared to that of an exemplary embodiment 31-5OCF (odor control fiber) treated with a solution of the present disclosure. The solution applied to the 31-5OCF sample contained 66.6 wt.% glycerol, 11.8 wt.% water, 18.0 wt.% β-cyclodextrin, and 3.6 wt.% citral (i.e., a molar ratio of citral:cyclodextrin of 1.5:1). At room temperature, the pH of the glycerol / water solution was adjusted to a pH of 12.5 using sodium hydroxide. The 31-5OCF sample was made at 86°C using 0.011 grams of solution added per gram of fluff to provide a citral addition of 0.4 kg of citral per air-dried metric ton of fluff. Using the following test method, the pH of the 31-5OCF sample was 5.8, untreated The pH of the villi was 6.0 as shown below in Table 4. The use of a relatively high pH solution had a negligible effect on the pH of the 31-5 OCF.

[0103] [Table 4]

[0104]

[0105] The method for determining the pH of the fiber is as follows. The pH of the fiber is determined by placing 2 g of the defiberized sample into a 500 mL conical flask. Add 100 g of distilled water at pH 6.5-7.0. Stop the flask with a glass stopper and shake until a thick slurry is obtained. Add an additional 100 g of distilled water to the flask, then stop the flask and shake briefly at intervals of about 15 minutes until the sample is completely slurried. After about 1 hour, pour about 50 mL of the slurry into a clean 150 mL beaker. This portion is used to rinse the beaker and then discarded. The remaining slurry is then poured into a beaker and the pH is measured using a pre-calibrated pH meter.

[0106] Example 3 :Dispensing amount / reaction of citral for urine odor control

[0107] In the following examples, the dispensing amounts and responses of citral for urine odor control in exemplary embodiments are determined.

[0108] Using the solution described in Example 2, an exemplary embodiment was prepared in which the amount of citral added varied from 0.1 to 3.3 kg citral per air-dried metric ton of fluff. The amount of citral added was varied by adjusting the amount of solution added. The fluff flake pulp was an untreated southern pine kraft pulp sold under the trade name JLDE is sold by Rayonier Advanced Materials of Jesup, Georgia. Table 5 below summarizes the variations used to determine the dispensing amounts and responses for citral for urine odor control.

[0109] [Table 5]

[0110]

[0111] like Figure 1 As shown, the odor control performance measured as the total odor score increases with increasing citral addition, reaches a value of about 0.3 to 0.4 kg citral per air-dried metric ton of fluff, and then remains constant to a value of 3.3 kg citral per air-dried metric ton of fluff.

[0112] The results of the resulting embodiments shown in Table 5 were evaluated according to the following method.

[0113] The urine odor of OCF was evaluated using a blind TRIANGULAR FORCED-CHOICE TEST METHOD and an expert panelist.

[0114] Sample preparation: Use a mold to prepare a sample with a basis weight of 400 g / cm 2 ±About 5g / cm 2 A single sample of 60 mm in diameter is cut from a sheet of airlaid fluff pulp having a density of about 0.06 g / cc. For each odor test, 8 samples of control material and 6 samples of unknown or test material are prepared. The samples are placed in a cylindrical carbonate or glass jar of 70 mm in diameter and 70 mm in height. The volume of a jar is about 270 cm 3 Each jar has a plastic screw cap. During the test, one sample is placed in each jar, distilled water or fresh urine is added, and heated in a water bath at 40°C ± 5°C. Dispensing (dosing) is done using a calibrated syringe, taking care to distribute the liquid evenly over the sample. Between tests, the jars are cleaned with unscented dishwashing liquid.

[0115] Test Design - There were two parts for the odor test. In part 1, urine was dispensed into one test sample and compared to two control samples dispensed with distilled water. In part 2, another test sample dispensed with urine was compared to two control samples also dispensed with urine. Table 6 below provides the comparison.

[0116] [Table 6]

[0117]

[0118]

[0119] For each test sample, there were 12 odor comparisons. There were two parts for the test, each with three levels of urine dispensed (i.e., 2.5, 5, and 10 g of liquid per g of dry sample) at 10 min and 100 min after dispensing. During the test, the samples were maintained at a temperature of 40°C ± 5°C. In part 1 of the test above, for convenience, the same two control samples with 10 g of water / g of villi were compared to three separate test samples prepared at the three urine dilution levels. Only two control samples with water were used because the odor of these control samples did not change after the jar was opened or over time. After the 10 min odor test, the samples were returned to the water bath for an additional 100 min before a final odor evaluation. For part 2 of the test, the two control samples with urine were compared to one test sample with urine, using a separate sample for each comparison. In total, six test material samples were prepared with urine (at each of the three dilution levels, for parts 1 and 2). Six control samples were prepared with urine (at each of three dilution levels for Parts 1 and 2), and two additional control samples were prepared with distilled water (10 g water / g villi) for Part 1.

[0120] Panelists - Each odor evaluation was conducted by having the test administrator remove the appropriate jar from the water bath and present it to the panelist blindly. The panelist opened the lid of each jar, smelled the headspace of each jar, and then replaced the lid. The panelists were instructed to choose one of the three jars that was different from the other two, even if they had to guess. This statistical method is called "triangular forced-choice". The panelists would tell the test administrator which sample was different and whether their choice was "detect" (i.e., one was sure that their choice was different from the other two) or "guess" (i.e., one was not sure that their choice was different from the other two). If the panelist made the correct choice and the choice was "detect", the test administrator recorded a value of "6" for the comparison. If the panelist guessed the choice, a value of "2" was recorded for the correct guess and a value of "0" was recorded for the incorrect guess. Table 7 below provides a description of the responses.

[0121] [Table 7]

[0122]

[0123] Odor values ​​of 2 and 6 are used because sensory responses such as odor follow a power law, where the apparent odor intensity increases as a power function of the dose or odor concentration, i.e., according to the following formula:

[0124] I = k C n (1)

[0125] and log 10 I=n log 10 C+log 10 K(2)

[0126] Where I is the intensity or strength of the odor, C is a measure of the mass concentration of the odorant, and k and n are constants that are different for each odorant. Equation (2) is plotted linearly on a logarithmic scale. The dilution level in the test (doubling at each step) is related to C (the mass concentration of the odorant). Using log 10 The transformation forced a uniform distribution (i.e., 0.301) between the levels of 2.5, 5, and 10 g liquid / g fluff. In the test, the upper and lower limits of the I or odor score were forced to be equal. Thus, log 10 (2*0.301)=4, which is the difference between the odor score values ​​6 and 2.

[0127] The panelists also provide the test administrator with an assessment of the pleasantness or unpleasantness of the test sample's odor relative to the control sample's odor. For example, if the panelist makes the correct choice and is confident of the choice (i.e., the choice is "detect"), and the odor of the selected test sample is more pleasant than the odor of the control sample, the test administrator will record a value of "+6" for the comparison. If the test sample is more unpleasant than the control sample, the test administrator will record a value of "-6".

[0128] There is another situation that can occur in the test. If a test sample with urine odor can be confidently identified relative to a control sample with water, but the test sample with urine has no detectable urine odor, the result is recorded as "±6", indicating that any odor is subjectively acceptable. For example, a lemongrass odor with no detectable urine odor may be as acceptable as a sample with no odor at all. The choice is up to the panelist's preference. When the odor score is added, a "±6" is scored as a "+6" because it is as good as the untreated control with distilled water.

[0129] Panelists for the smell test can be recruited from the community at large. People who smoke, are pregnant, or have chronic allergies or asthma or nasal congestion are not candidates for the smell panel. For the test, panelists must be free of colds and other respiratory illnesses and must not chew gum or eat 30 minutes before the test. Panelists must not use perfume, cologne, aftershave, or scented deodorant on the day of the test. Samples are prepared for each panelist using fresh urine collected from that panelist on the morning of the smell test. Panelists are only asked to smell their own urine. Urine is discarded at the end of each day.

[0130] Odor Score Analysis - The following examples illustrate the calculation and analysis of odor scores. The first example is OCF 31-4 compared to untreated Fluff pulp testing. That is, The fluff pulp was the control sample for this odor test.

[0131] [Table 8]

[0132]

[0133]

[0134] In part 1 of the test, at the 2.5g and 5g urine / g 31-4OCF samples (10min), the odor score was ±6. This indicates that there was no detectable urine odor on the 31-4OCF samples compared to the untreated fluff with distilled water. At the 10g urine / g 31-4OCF samples, the lemongrass odor was barely detectable, but there was still no detectable urine odor. At the 10g urine / g 31-4OCF samples and 100min, there was a detectable urine odor on the 31-4OCF samples and an odor score of "-6" was recorded.

[0135] In part 2 of the test, the urine was compared to the untreated The odor of the 31-4OCF sample with urine was detectable (and more pleasant) (i.e., a "+6" value). At 100 min and the highest level of urine quantification (i.e., 10 g urine / g fiber), the panelists had to guess, but correctly guessed that the 31-4OCF sample was different and its odor was more pleasant.

[0136] The second example is a test of the 31-4OCF sample compared to itself. That is, the 31-4OCF sample was the control sample in this odor test.

[0137] [Table 9]

[0138]

[0139] In part 1 of the test, the odor score values ​​were negative. This is probably because it was easier to detect the slight smell of urine in the odorous 31-4 sample with urine compared to the odorous 31-4 sample with water than it was to detect the smell of urine in the odorous 31-4 sample with urine compared to the unscented fluff sample with water in the first embodiment. All values ​​in part 2 of the test were "0". All samples were identical, and the panelists had to guess which one was arbitrarily designated as the test sample. The panelists guessed incorrectly in all cases, despite a 33% chance of making the correct choice by chance.

[0140] The odor score obtained from Part 1 of the test is a comparison of the unknown material with urine to the control material with distilled water. The odor score obtained from Part 2 of the test is a comparison of the same unknown material with urine to the same control material with urine. The total odor score is the sum of the odor scores from Part 1 and Part 2 of the test. Variations of this test can be used with samples containing superabsorbent polymers and samples cut from absorbent cores and absorbent products, as well as using other reference materials for control. The odor score provides a good semi-quantitative measure of the effectiveness of the odor control of the present invention.

[0141] Example 4 :Odor control properties of citral / β-cyclodextrin complex

[0142] The following examples characterize the unexpected discovery that the odor control performance of β-cyclodextrin / citral complexes can be enhanced by forming the complex in a solution at pH 12.5 and applying the solution at elevated temperature, allowing the complex to precipitate in situ on the fiber surface at room temperature. The following examples also characterize the unexpected discovery that the odor control performance of the citral:β-cyclodextrin complex exhibits optimal effects at a molar ratio of citral:β-cyclodextrin of about 1.5:1.

[0143] Table 10 below shows the performance of exemplary citral / β-cyclodextrin embodiments with reduced citral addition (kg citral / air-dried metric ton of fluff) using citral:β-cyclodextrin molar ratios of 1.0:1, 1.5:1, and 1.75:1. In addition, the control sample used to generate the odor score was untreated 10% cellulose fiber from Rayonier Performance Fibers, LLC. fluff. Odor scores were determined by the triangular forced choice test method described above. As seen in Table 10 below, odor control performance was best for a citral:β-cyclodextrin molar ratio of 1.5:1, at which molar ratio, odor control performance was independent of citral addition over the range of 3.3 to 0.4 kg citral / AMDT fluff pulp. A citral:β-cyclodextrin molar ratio of 1.75:1 had a slightly detectable odor and color on the fluff pulp, indicating that not all of the citral was complexed with the cyclodextrin.

[0144]

[0145] The best odor control performance was achieved using a citral:β-cyclodextrin molar ratio of 1.5:1 and a solution pH of 12.5. Table 11 below shows the performance of an exemplary citral / β-cyclodextrin embodiment made with a citral:β-cyclodextrin molar ratio of 1.5:1 as a function of solution pH, mixing temperature, and application temperature. The first group of three samples was made with solutions mixed and applied at an elevated temperature of 86°C. For the second group, the solutions were mixed at elevated temperature but allowed to cool and applied at room temperature. The solutions were mixed and applied to the third group at room temperature. The odor scores for each group increased (i.e., improved performance) with increasing pH. There were no significant differences between the two groups due to normal variation in odor test scores.

[0146]

[0147] The control sample used to generate the odor scores in Table 11 was the 31-4 sample used in Example 3. The 31-4 sample was also tested as sample number 1 in Table 11 above. All water (i.e., control group) and urine odor scores were negative because detecting slight differences in urine odor between similar odor samples is more difficult than detecting odorous samples and non-odorous samples (such as water-treated samples). The 31-4 sample was preferred because the composite formed a clear, homogeneous solution at an elevated temperature of about 86°C. This step did not improve the odor control performance of the composite. However, it greatly improved the ability to handle the solution and apply it uniformly to the substrate surface. The β-cyclodextrin / citral composite solution sprayed on the fluff pulp at an elevated temperature of about 86°C precipitated in situ on the fiber surface when the fiber cooled to room temperature.

[0148] Turbidity is an indicator of the solubility of the complex in solution. Soluble complexes form clear, water-white solutions. Insoluble complexes form opaque, milky dispersions that may settle over time. A milky dispersion will form if the 86°C solution is cooled to room temperature, or if no heat is applied during the mixing or application steps. A milky dispersion of the complex is applied to a fluff pulp using a simulated laboratory kiss roll method. A known amount of the milky dispersion is applied to a glass surface and the fluff pulp piece is contacted to the glass surface immediately before the dispersion dries. The wet pick-up of the dispersion is estimated by immediately weighing the fluff pulp piece.

[0149] Without being limited to the unique and complete understanding of the physicochemical modifications imparted by the interaction of the citral / β-cyclodextrin complex with the solution pH, the inventors believe that the unique physical form of the precipitate formed on the solid cellulose surface may lead to the unexpected improvement in odor control of the samples prepared using a high solution pH of 12.5. Figure 2 and Figure 3The following micrograph shows the particle size of the citral / β-cyclodextrin complex precipitated from a glycerol / water solution at pH 12.5 and 9.6 at 86°C after the solution was cooled to room temperature.

[0150] The solid particles of the complex precipitated from the solution at pH 12.5 were uniform in size, approximately 50 μm in diameter. The particle sizes precipitated from the solution at pH 9.6 were in the range of 100-400 μm. It was an unexpected discovery to learn that the odor control properties of the β-cyclodextrin / citral complex can be enhanced by forming the complex in a glycerol / water solution, with a molar ratio of citral:β-cyclodextrin of approximately 1.5:1, and a high pH of approximately 12.5.

[0151] Example 5 :Substrate preparation

[0152] The samples were prepared using β-cyclodextrin from Acros Organics and citral, a volatile lemongrass essential oil from Perfumer's Apprentice, using a glycerol / water ratio of 85 / 15 and a pH adjustment of 9.6. The solutions were mixed and applied at a temperature of 86°C. At the 86°C application temperature, the components formed a clear, water-white solution. The molar ratio of citral to β-cyclodextrin was 1.0. The citral addition rate was 2.4 kg of citral per air dried metric ton ("ADMT") of fluff. The fluff flake pulp was an untreated southern pine kraft pulp sold under the trade name JLDE is sold by Rayonier Advanced Materials in Jesup, Georgia. The calculated increase in moisture content of the substrate was 1.0 wt. %. Using METTLER The moisture content of the treated sample was checked with a moisture analyzer, with the moisture content of 6.29% ± 0.18% and the moisture content of the untreated Rayfloc control was 5.33% ± 0.39%. The test value of the moisture gain of the sample was obtained to be 0.96%. Because the moisture gain was less than about 1 wt.% or less, no drying step was required. The overall odor score was -28, as determined by the blind, triangular forced-choice test method and expert panel discussed above. Even with the addition of relatively high amounts of citral, the sample did not provide good odor control performance. The amount of citral added was 2.4 kg of citral per air dried metric ton ("ADMT") of fluff. Because the molar ratio of citral:β-cyclodextrin was less than 1.5:1 and the solution pH was less than pH 12, the odor control performance was poor. Table 12 and

[0153] Table 13 gives the specifications and odor score measurements for Example 5.

[0154]

[0155] [Table 13]

[0156]

[0157] Example 6 :Substrate preparation

[0158] The samples were prepared using 85 / 15 glycerol / water ratio and a pH adjustment of 12.5 using β-cyclodextrin from Acros Organics and citral from Perfumer's Apprentice. The solutions were mixed and applied at a temperature of 86°C. At an application temperature of 86°C, the components formed a clear, water-white solution. The molar ratio of citral to β-cyclodextrin was 1.0. The citral addition rate was 2.4 kg of citral per air dried metric ton ("ADMT") of fluff. The fluff flake pulp was untreated Southern pine kraft pulp sold under the trade name JLDE is sold by Rayonier Advanced Materials of Jesup, Georgia. The calculated moisture gain of the substrate was 1.0 wt.%. Because the moisture gain was less than about 1 wt.% or less, no drying step was required. The total odor score was +16 as determined by the blind, triangular forced choice test method and expert panel discussed above. Due to the increase in solution pH from 9.6 to 12.5, this sample provided better odor control than the sample in Example 5. Tables 14 and 15 give the specifications and odor score measurements for Example 6.

[0159]

[0160] [Table 15]

[0161]

[0162] Example 7 :Substrate preparation

[0163] The samples were prepared using 85 / 15 glycerol / water ratio and a pH adjustment of 12.5 using β-cyclodextrin from Acros Organics and citral from Perfumer's Apprentice. The solutions were mixed and applied at a temperature of 86°C. At an application temperature of 86°C, the components formed a clear, water-white solution. The molar ratio of citral to β-cyclodextrin was 1.5. The citral addition rate was 2.0 kg of citral per air dried metric ton ("ADMT") of fluff. The fluff flake pulp was untreated Southern pine kraft pulp sold under the trade name JLDE is sold by Rayonier Advanced Materials of Jesup, Georgia. The calculated moisture gain of the substrate was 0.6 wt.%. Because the moisture gain was less than about 1 wt.% or less, no drying step was required. The overall odor score was +56 as determined by the blind, triangular forced choice test method and expert panel discussed above. Due to the molar ratio of citral to beta-cyclodextrin of 1.5:1 and the solution pH of 12.5, this sample has very good odor control performance. Tables 16 and 17 give the specifications and odor score measurements for Example 7.

[0164]

[0165] [Table 17]

[0166]

[0167] Example 8 :Substrate preparation

[0168] The samples were prepared using 85 / 15 glycerol / water ratio and a pH adjustment of 12.5 using β-cyclodextrin from Acros Organics and citral from Perfumer's Apprentice. The solutions were mixed and applied at a temperature of 86°C. At an application temperature of 86°C, the components formed a clear, water-white solution. The molar ratio of citral to β-cyclodextrin was 1.5. The citral addition rate was 0.4 kg of citral per air dried metric ton ("ADMT") of fluff. The fluff flake pulp was untreated Southern pine kraft pulp sold under the trade name Sold by JLDE, available from Rayonier Advanced Materials in Jesup, Georgia. The calculated moisture gain of the substrate was 1.0 wt.%. Because the moisture gain was less than about 1 wt.% or less, no drying step was required. The overall odor score was +52 as determined by the blind, triangular forced choice test method and expert panel discussed above. With only 0.4 kg of citral / ADMT fluff pulp added, the sample provided odor control performance that was as good as the odor control performance of the sample with 2.0 kg of citral / ADMT fluff pulp added (i.e., Example 7). Tables 18 and 19 give the specifications and odor score measurements for Example 8.

[0169]

[0170] [Table 19]

[0171]

[0172] Example 9 :Substrate preparation

[0173] The samples were prepared using 100% water (i.e., a 0 / 100 ratio of glycerol / water) and a pH adjustment of 12.5 using β-cyclodextrin from AcrosOrganics and citral from Perfumer's Apprentice. The solutions were mixed and applied at a temperature of 86°C. At an application temperature of 86°C, the components formed a relatively stable milky white dispersion. The molar ratio of citral to β-cyclodextrin was 1.5. The amount of citral added was 0.4 kg of citral per air dried metric ton ("ADMT") of fluff. The fluff flake pulp was untreated Southern pine kraft pulp sold under the trade name Sold by JLDE, available from Rayonier Advanced Materials of Jesup, Georgia. The calculated moisture gain of the substrate was 1.1 wt.%. Because the moisture gain was less than about 1 wt.%, no drying step was required. The overall odor score was +36 as determined by the blind, triangular forced choice test method and expert panel discussed above. The odor control performance of this reduced cost 100% aqueous solution sample was good and almost as good as the odor control performance of the sample prepared with the 85 / 15 glycerol / water solution in Example 8. After the addition of citral and the formation of the complex at 86°C, the mixture formed a dispersion, but when the concentration of cyclodextrin and citral in the solution was less than about 20 wt.%, the size of the precipitated particles was very small, the odor control performance was good, and the dispersion could be easily sprayed onto the substrate. Table 20 and

[0174] Table 21 gives the specifications and odor score measurements for Example 10.

[0175]

[0176] [Table 21]

[0177]

[0178] Conclusion and Summary of Examples 5-9

[0179] In Table 22 below, a summary of Examples 5 to 9 is given. Increasing amounts of the citral:cyclodextrin molar ratio of 1:1 to 1.5:1 increased the odor control performance (as indicated by increasing the total odor score) about as much as increasing the solution pH from 9.6 to 12.5 at a glycerol / water ratio of 85 / 15 and citral additions in the range of 2.0-2.4 kg citral / ADMT fluff pulp. The unadjusted pH of the solution was about 6.5. Also at a citral:cyclodextrin molar ratio of 1.5:1 and a pH of 12.5, the same solution provided with a reduced citral addition of 0.4 kg citral / ADT fluff pulp provided about the same level of very good performance (i.e., +52). Examples 5 to 8 had clear, water white solutions at a mixing and application temperature of 86°C. When the solution and treated fibers cooled to room temperature, the composite precipitated on the surface of the cellulose fibers.

[0180] [Table 22]

[0181]

[0182] It was an unexpected discovery to learn that the odor control performance of the β-cyclodextrin / citral complex can be greatly enhanced by forming the complex in a glycerol / water solution having a citral:β-cyclodextrin molar ratio of about 1.5:1 and a high pH of about 12.5.

[0183] The exact physical size and morphology of the cyclodextrin complex precipitated in situ on the solid fiber surface has not been characterized. However, without being limited to a particular theory, the inventors believe that the particle size of the complex precipitated in solution when the solution is cooled to room temperature is a measure of the morphology of the complex on the substrate surface. At pH 12.5 at elevated temperatures, the average particle size of the solid particles of the complex precipitated from the solution is in the range of 50 μm or less. In order to obtain good odor control performance, a solution pH of about 12.5 or higher should be used. When the substrate is treated with a solution having a pH of 9.6 or less, the odor control performance is poor. At pH 9.6 or less at elevated temperatures, the average particle size of the solid particles of the complex precipitated from the solution is in the range of 100-400 μm. Among other things, the particle size is believed to be controlled by the solution pH.

[0184] The results discussed above are unexpected and surprising. In the prior art, there is no known discussion of the effect of pH on the odor control properties of cyclodextrin complexes. This effect may be consistent with the inventor's additional discovery that when the complex is precipitated from a solution at a pH of about 12.5, it precipitates into very fine particles. The odor control properties of the complex precipitated from the solution may be related to its solid phase morphology on the substrate surface. The hydroxyl groups on the outer surface of the cyclodextrin molecule begin to deprotonate at about pH 12 (i.e., pKa range of about 12.1-13.5). It is known that cyclodextrins and their complexes form aggregate structures through self-assembly in solution. This aggregate formation may be affected by the surface charge associated with deprotonation, and in turn affects the size of the precipitated particles and the morphology of the complex precipitated on the substrate surface. Other patents, such as in U.S. Patent No. 5,429,628, claim that small cyclodextrin particles increase the release and release rate of active substances. When the complex is wetted, particles less than about 12 microns are preferred to provide rapid release of the active compound. However, US Pat. No. 5,429,628 achieves such particle size reduction via grinding and pulverization in a fluid energy mill, or by agitation or ultrasound. The inventors are not aware of using solution pH to adjust the particle size of cyclodextrin complexes, as disclosed herein.

[0185] The inventors have also surprisingly discovered that odor control performance is sensitive to the molar ratio of citral to cyclodextrin in the complex. U.S. Patent No. 5429628 and WO 98 / 26808 indicate that, in general, the molar ratio of perfume to cyclodextrin for perfume / cyclodextrin complexes is about 1:1, although sometimes greater, but typically the perfume to cyclodextrin loading is about 7 wt.% to 12 wt.%. There are practical limits to the loading of perfume in cyclodextrin complexes, but the inventors are not aware of any disclosure about how loading affects odor control performance. For citral / β-cyclodextrin complexes, a molar ratio of citral to β-cyclodextrin of 1:1 would correspond to a loading of 11.8 wt.%, as generally disclosed by U.S. Patent No. 5429628. However, a molar ratio of citral to β-cyclodextrin of 1.5:1 would correspond to a loading of 16.7 wt.%. Considering that the water content of β-cyclodextrin is 10 wt.%, a molar ratio of citral to dry β-cyclodextrin of 1.5:1 would correspond to a loading of 18.3 wt.%. That is, such a range of citral loadings is far beyond the range taught in U.S. Patent No. 5,429,628. The inventors are unaware of a technical explanation for the higher range of citral loadings disclosed, which may be due to the high solution pH of the complex formation. Although it is possible that the actual quantitative values ​​may be different for different essential oil loadings, the inventors anticipate that the requirements for achieving excellent odor control include: a minimum loading of essential oils on cyclodextrin and a solution pH of about 12.0 or above as common features of these systems.

[0186] The composites in Examples 5 to 9 form clear, uniform solutions at an elevated temperature of about 86°C. This step does not improve the odor control properties of the composites. However, it greatly improves the ability to handle the solution and apply it uniformly to the surface of the substrate. At an elevated temperature of about 86°C, the solution of the β-cyclodextrin / citral composite sprayed on the fluff pulp precipitates in situ on the fiber surface when cooled to room temperature. The solution concentration of the citral / cyclodextrin composite ranges from 21.6 wt.% to 24.9 wt.%. The solution concentration of the composite can reduce the amount of solution added to keep the increase in the moisture content of the substrate below about 1 wt.%. However, the ratio of the odor control compound to the cyclodextrin also helps to give the substrate good odor control properties. For citral, the optimal molar ratio of citral to β-cyclodextrin is about 1.5-1.75 mol citral to 1.0 mol β-cyclodextrin. When the molar ratio is about 1:1 or lower, the odor control performance is reduced (adding citral in equal amounts to the substrate). When the molar ratio is 1.75:1 or greater, the volatile, uncomplexed citral imparts unwanted color and odor to the substrate. Volatile, expensive fragrance essential oils used in absorbent products tend to be lost prematurely. It is desirable to have an essential oil contained in a stable complex and released only when in contact with aqueous body fluids.

[0187] The ratio of glycerol / water also plays a role in the solution chemistry discussed above. For example, even though samples were prepared at the preferred 1.5 mole citral: mole cyclodextrin and pH 12.5, samples prepared with a higher ratio of water (e.g., 50% glycerol / 50% water) did not perform as well as those samples made with a ratio of 85% glycerol / 15% water.

[0188] However, it is noteworthy that Example 9 provides nearly as good odor control performance using a 100% aqueous solution and is able to deliver 0.4 kg of citral / ADT fluff pulp with only a 1.1% increase in moisture. This unexpected practical discovery provides good odor control performance at a greatly reduced raw material cost. In this example, in order to obtain good odor control performance from a 100% aqueous solution, the conditions for the formation of a fine precipitate when citral is added to the β-cyclodextrin / water solution must be appropriate. The solution concentration of the complex at 86°C and pH 12.5 is lower, in the range of about 18 wt.% or less. At higher concentrations, an undesirable coarse precipitate forms and the odor control performance deteriorates.

[0189] Examples 10 to 17

[0190] Triangular Forced Choice Odor Evaluation Test Protocol Used in Examples 10 to 17

[0191] Odor score is derived from the comparison of test sample with reference sample or control sample. Odor score is not an absolute value. Test and control samples are all dosed with fresh human urine, which is aged at room temperature for 8 to 12h to increase malodor. The odor score in the following examples 10 to 17 is the sum of four head-to-head comparisons of the test sample compared with the reference sample at two urine distribution levels (i.e. 5g and 10g of urine per g villi) and after distribution twice (i.e. 10min and 100min). The score range for this comparison is -24 to +24. In this triangular forced choice odor evaluation test, the panelists select one of the three samples, which has a different odor from the other two. The possibility of "no difference" must be selected by the panelists. Guessing is when the panelists are not sure about their choice. Detection is when the panelists are sure about their choice. The grading scale is provided in Table 23 below:

[0192] [Table 23]

[0193] Odor score explanation 0 Correct guess +2 Correct guess (unknown is better than control) -2 Correct guess (unknown is worse than control) +6 Correct detection (unknown is better than control) -6 Correct detection (unknown is worse than control) ±2 Correct guess (preference determines whether it is good or bad) ±6 Correct detection (preference determines whether it is good or bad) Scores of ±2 and ±6 are counted as +2 and +6 respectively

[0194] The samples in Examples 10 to 17 were also tested at two lower urine partitioning levels (i.e., 5.0 g of urine per g of villi at 10 and 100 min) versus conventional villi. The scores for this comparison ranged from -12 to +12. With the exception of the conventional villi sample in Example 17, all of the test and control samples in Examples 10 to 17 scored +12 compared to conventional villi. This indicates that all of the control and test samples in Examples 10 to 17 masked urine better than conventional villi.

[0195] Example 10 : Comparison of citral / coconut fragrance oil blend with citral alone

[0196] A sample similar to that described in Example 9 was prepared using 100% water (i.e., a 0 / 100 ratio of glycerol / water) and a pH adjustment of 12.5, using β-cyclodextrin from Wacker Chemical Co. and citral from Advanced Biotech. The solution was prepared with a molar ratio of citral to β-cyclodextrin of 1.6 instead of 1.5, which was not a significant difference, and mixed and applied at a temperature of 86°C. The amount of citral added was 0.4 kg of citral per air dried metric ton ("ADMT") of fluff. Flaky fluff pulp is an untreated southern pine kraft pulp sold under the trade name Sold by JLDE, available from Rayonier Advanced Materials in Jesup, Georgia. The calculated moisture increase of the substrate was 1.0 wt.%. Because the moisture increase was about 1 wt.%, no drying step was required. This sample (identified as 4-1) was used as a control sample in the triangular forced choice odor evaluation compared to the test sample (identified as 12-1, which was prepared using an equimolar mixture of citral and coconut fragrance oil at the same mixing and application temperature of 86°C and the same total essential oil to β-cyclodextrin molar ratio of 1.6). The total essential oil addition of the equimolar mixture of citral and coconut fragrance oil was increased to 0.46 kg per air dried metric ton ("ADMT") of fluff to keep the samples at comparable raw material costs. The coconut fragrance oil provided by Perfumer's Apprentice is a mixture of several essential oils, which are shown in Table 24 below.

[0197] [Table 24]

[0198]

[0199] The weighted average molecular weight of coconut oil is about 180.2 g / mol. Sample 12-1 was also prepared using β-cyclodextrin from Wacker Chemie and citral from Advanced Biotech.

[0200] Compared to control sample 4-1, the odor score of test sample 12-1 containing citral / coconut fragrance oil mixture is +24, which exceeds the possible range of -24 to +24 determined in the blind triangle forced choice test discussed above. This shows that the equimolar mixture of citral and coconut fragrance oil (at a slightly higher addition level but at a comparable raw material cost) improves the odor control performance compared to the sample made with citral alone. Table 25 (control sample 4-1) and Table 26 (test sample 12-1) give the specifications of control sample 4-1 and test sample 12-1. Table 27 gives the odor score measurement of the mixed test sample 12-1 compared to control sample 4-1 (the odor score of test sample 12-1 is compared to the odor score of control sample 4-1).

[0201]

[0202]

[0203] Embodiment 11 :The mixing temperature of the solution was reduced from 86℃ to 50℃ by increasing the EO to CD molar ratio from 1.6 to 4.0

[0204] Sample 4-1 described in Example 10 above was used as a control sample in a triangular forced choice odor evaluation and was compared to a new test sample (identified as 52-1) prepared at a lower mixing temperature and a higher molar ratio. The reduction in mixing temperature reduced the solubility and dispersibility of the citral / β-cyclodextrin complex. This reduced dispersibility caused the precipitated complex to settle at a mixing temperature of 50°C. It was difficult to apply this dispersion to a substrate and the odor control performance was also poor. Removal of β-cyclodextrin from the solution resulted in an increase in the citral to β-cyclodextrin molar ratio to a value of 4.0, which allowed the solids to be effectively dispersed at 50°C. At 50°C, the dispersion used to prepare test sample 52-1 was milky white with no obvious precipitation or particle settling.

[0205] Test sample 52-1 was prepared using 100% water and a pH adjustment of 12.5 using β-cyclodextrin from Wacker Chemie and citral from Advanced Biotech. The solution was prepared at a molar ratio of citral to β-cyclodextrin of 4.0 and mixed and applied at a temperature of 50°C (indicated as 50C / 50C in the table). The amount of citral added was increased to 0.5 kg of citral per air dried metric ton ("ADMT") of fluff. The fluff flake pulp was untreated Southern pine kraft pulp sold under the trade name JLDE is sold by Rayonier Advanced Materials of Jesup, Ga. The calculated moisture gain of the substrate was 1.3 wt. %. Because the moisture gain was not much higher than 1 wt. %, no drying step was required.

[0206] The odor score of test sample 52-1 compared to control sample 4-1 was +20, which was beyond the possible range of -24 to +24 as determined by the blind triangular forced choice test discussed above. An increase in the molar ratio of citral to β-cyclodextrin from a value of 1.6 to 4.0 improved the odor control performance. Unexpectedly, relatively good dispersibility of the solution was found at a mixing temperature of only 50°C. Also unexpectedly, at a high molar ratio of citral to cyclodextrin of 4.0, there was no citral odor on the dried sample 52-1. This indicates that under dry storage conditions, most of the volatile citral oil is bound to the substrate. The specifications of control sample 4-1 and test sample 52-1 are shown in Tables 25 and 28 (test sample 52-1). Table 29 gives the odor score measurements of test sample 52-1 compared to control sample 4-1.

[0207]

[0208] [Table 29]

[0209]

[0210] Example 12: After adding corn syrup, the pH value of d-limonene solution at 50°C dropped from 12.5 to 10.9

[0211] The reduction in pH reduces the solubility and dispersibility of the citral / β-cyclodextrin complex, just as the effect of reduced temperature on solubility and dispersibility. It is possible to improve the dispersibility of the complex at pH 10.9 by reducing the solids concentration of the solution by adding water. This allows the solution pH to be reduced at a temperature of 50°C and maintain certain odor control properties, but this approach results in an undesirable increase in the moisture content of the fluff pulp, sometimes exceeding 2%. An example of this approach is sample 46-B shown in Table 40. In an attempt to find an additive that would interfere with the crystallization and / or precipitation of the dispersed complex at reduced temperature and pH, it was found that the addition of small amounts of corn syrup (i.e., glucose) was effective in maintaining a sufficiently stable, milky white dispersion at pH 10.9 and 50°C without significant precipitation or particle settling. It is believed that the smaller glucose molecules interact with the outer surface of the chemically similar β-cyclodextrin complex to reduce the rate and amount of crystallization and / or precipitation of the complex. In the following examples, the beneficial effects of adding glucose to the solution are demonstrated using d-limonene and β-cyclodextrin complexes.

[0212] Test sample 65-1 was prepared using 82.7% water and 9.2% Karo Light corn syrup at 50°C and pH 10.9, using β-cyclodextrin from Wacker Chemical and d-limonene from Florida Chemical in place of citral from Florida Chemical. For the calculations in Table 28, the water content of the corn syrup was estimated to be 25 wt.%. The solution was prepared at a d-limonene to β-cyclodextrin molar ratio of 4.0, mixed at a temperature of 50°C and applied. The corn syrup was added to the water before the pH was adjusted. Any fine precipitate formed was suspended for several hours. This is a very easy solution / suspension to handle and spray during processing of pulp sheets. The d-limonene was added at a rate of 0.5 kg of d-limonene per air dried metric ton ("ADMT") of fluff. The sheet fluff pulp was untreated Southern pine kraft pulp sold under the trade name Sold by JLDE, available from Rayonier Advanced Materials of Jesup, Georgia. The calculated moisture increase of the fluff pulp substrate was 1.6 wt.%. No drying step was required.

[0213] The odor of test sample 65-1 was tested compared to control sample 52-1. Sample 52-1 was used as the test sample for Example 11. In paired comparisons, sample 52-1 performed better than sample 4-1 of Example 11 in terms of odor control, and sample 65-1 performed better than sample 52-1 of Example 12. The odor score of test sample 65-1 compared to control sample 52-1 was +24, which was beyond the possible range of -24 to +24 as determined by the blind triangular forced choice test discussed above. Adding 9.2 wt.% corn syrup to the solution when using d-limonene greatly improved the dispersibility of the complex in the solution and provided a good masking of urine odor. There was no odor on the dried sample of 65-1. The specifications of control sample 52-1 and test sample 65-1 are given in Table 28 (above) and Table 30 (test sample 65-1). The odor score measurements of test sample 65-1 versus control sample 52-1 are given in Table 31 (Odor Score of Test Sample 65-1 versus Control Sample 52-1).

[0214]

[0215] [Table 31]

[0216]

[0217] Example 13 : After adding corn syrup, the equimolar d-limonene / octanol mixture achieved a decrease in solution pH from 12.5 to 10.9 at 50°C

[0218] A sample similar to that described in Example 12 was prepared using an equimolar mixture of d-limonene and octanol instead of 100% d-limonene. For the calculations in Table 30, the water content of the corn syrup was estimated to be 25 wt.%. The odor of the test sample 67-1 compared to the control sample 52-1 was tested. Sample 52-1 was used as a test sample for Example 11 and a control sample for Example 12. The odor score of the test sample 67-1 compared to the control sample 52-1 was +24, which exceeded the possible range of -24 to +24, as determined in the blind triangular forced choice test discussed above. Adding 9.2 wt.% corn syrup to the solution and using an equimolar mixture of d-limonene and octanol greatly improved the dispersibility of the complex in the solution and provided a good masking of the urine odor. There was no odor on the dried sample of 67-1. The specifications of the control sample 52-1 and the test sample 67-1 are shown in Tables 28 and 32 (test sample 67-1). Table 33 gives the odor score measurements of test sample 67-1 and control sample 52-1 (Odor Scores of Test Sample 67-1 and Control Sample 52-1).

[0219]

[0220] [Table 33]

[0221]

[0222] Embodiment 14 : Further increase in EO / CD molar ratio and decrease in pH and mixing temperature

[0223] Samples similar to sample 67-1 described in Example 13 (Table 32) were prepared to expand the range of key variables such as pH, mixing temperature, and EO / CD molar ratio. These samples were prepared using an equimolar mixture of d-limonene and octanol. The solutions used to prepare these samples contained 9.2% to 9.4% corn syrup, and the water content of the corn syrup was estimated to be 25 wt.%. The solution pH and mixing temperature of sample 67-1 were pH 10.9 and 50°C, respectively. The pH of the solution used to prepare sample 68-1 was pH 7.0, and the mixing temperature of the solution used to prepare sample 69-1 was 20°C. As with sample 67-1, the CD and EO solution concentrations of both samples were 8.1%. The solution used to prepare sample 74-1 was prepared with an increased EO / CD molar ratio of 6.0, while for 67-1, it was prepared with an EO / CD molar ratio of 4.0, and the pH and mixing temperature of 74-1 were 10.9 and 50°C, respectively. Due to the reduced amount of cyclodextrin, the solution concentration of CD and EO of sample 74-1 is only 6.4%. The specifications of sample 74-1 are given in Table 34.

[0224]

[0225] Test samples 68-1, 69-1 and 74-1 were tested against control sample 67-1 for urine malodor. The odor scores of test samples 68-1, 69-1 and 74-1 compared to control sample 67-1 are summarized in Table 35 as determined by a blind, triangular forced choice test method.

[0226] [Table 35]

[0227]

[0228] The odor scores for test samples 68-1, 69-1, and 74-1 show that none of these samples are as good as control sample 67-1, but their odor control performance is still relatively good. The odor control performance of sample 69-1, prepared with a solution mixing temperature of 20°C, is almost as good as the odor control performance of control sample 67-1. Decreases in pH and increases in molar ratio have a greater negative impact on odor control performance than temperature. These samples are used to establish the range of key factors for optimal odor control performance for samples containing corn syrup.

[0229] Embodiment 15: Further reduction of corn syrup solution concentration

[0230] Samples similar to sample 67-1 described in Example 13 (Table 32) were prepared to expand the range of the key variable of corn syrup solution concentration. These samples were prepared using an equimolar mixture of d-limonene and octanol. The solutions used to prepare these samples contained 9.2% to 3.3% corn syrup, and the water content of the corn syrup was estimated to be 25 wt.%. The pH of the solutions used to prepare the samples was 10.9, the mixing temperature was 50°C, and the EO / CD molar ratio was 4.0. The solution concentrations of CD and EO ranged from 8.1% to 13.8%. The specifications for samples 72-1, 70-1, and 82-1 are given in Tables 36, 37, and 38.

[0231]

[0232]

[0233]

[0234] Test samples 72-1, 70-1, and 82-1 were tested against control sample 67-1 for urine malodor. The odor scores of the test samples versus control sample 67-1 are summarized in Table 39 as determined by a blind, triangular forced choice test method.

[0235] [Table 39]

[0236]

[0237] The odor control performance of samples 67-1, 72-1 and 70-1 decreases with increasing CD and EO solution concentrations and decreasing corn syrup solution concentrations. Sample 82-1 illustrates that low concentration corn syrup in the 3.3% range is effective when the total CD and EO solution concentration is as low as about 8% to 9%.

[0238] Example 16: Summary of samples in Examples 10 to 17

[0239] The relative odor control performance of the samples in Examples 10 to 17 is also summarized using odor performance scores, which provides a continuous performance scale based on multiple pairwise comparisons. For example, if sample 4-1 is +24 compared to conventional fluff, and sample 52-1 is +20 compared to sample 4-1, and sample 67-1 is +24 compared to sample 52-1, and sample 67-2 is +68 compared to conventional fluff. The scale is not linear, and a given quantitative difference at the low end of the scale is more meaningful than the same difference at the upper end. These continuous odor control scores for the samples are shown in Table 40. The range of key factors for optimal odor control performance is also shown in the table. The key factors are the amount of total essential oil (EO) added in the substrate, the solution mixing temperature, the essential oil to cyclodextrin molar ratio in the solution, the solution pH, and the corn syrup concentration in the solution.

[0240]

[0241] Embodiment 17 : Comparison of odor control fluff samples with conventional fluff

[0242] In the odor control test, all test and control samples in Examples 10 to 16 scored a perfect +12 points compared to conventional fluff. This shows that the samples in Examples 10 to 16 mask urine malodor much better than conventional fluff. Table 41 below provides an example of the odor scores of two test samples compared to a conventional fluff control sample.

[0243] [Table 41]

[0244]

[0245] In the above description, solutions containing cyclodextrins for giving odor control to materials used in absorbent products and related products and methods of the present application have been described with reference to specific embodiments thereof. However, it is obvious that various modifications and changes may be made thereto without departing from the broader spirit and scope of the present invention. Therefore, the description and drawings should be regarded as illustrative rather than restrictive. Throughout this specification, unless the context otherwise requires, the word "comprise" and its variants, such as "comprises" and "comprising", will be understood to imply the inclusion of the described items, elements or steps or a group of items, elements, steps, but not excluding any other items, elements or steps or other groups of items, elements and steps. In addition, the indefinite article "a" or "an" is meant to indicate one or more items, elements or steps modified by the article.

Claims

1. A substrate comprising an odor control solution applied thereto, wherein the odor control solution comprises: water, cyclodextrin, an odor control compound, and optionally a polar organic solvent, wherein the substrate comprises: at least 0.2 kg of the odor control compound per 1000 kg of the substrate, and Wherein the moisture content of the substrate increases by less than 2 wt.% since the odor control solution has been applied to the substrate.

2. The substrate of claim 1, wherein the odor control solution further comprises a stabilizing additive.

3. The substrate of claim 1, wherein the odor control solution comprises 1.5-6 moles of the odor control compound per mole of the cyclodextrin.

4. The substrate of claim 1, wherein the pH of the odor control solution is greater than 9 and less than 12.

5.

5. The substrate of claim 1, wherein the odor control solution comprises from about 6 wt.% to about 19 wt.% of the cyclodextrin and the odor control compound.

6. The substrate of claim 1, wherein the odor control compound is selected from the group consisting of citral, coconut oil, d-limonene, caprylic alcohol, and combinations thereof.

7. The substrate of claim 1, wherein the moisture content of the substrate increases by less than 1.7 wt.% as a result of applying the odor control solution to the substrate.

8. The substrate of claim 3, wherein the odor control solution comprises 3.5-4.5 moles of the odor control compound per mole of the cyclodextrin, and wherein the odor control solution is mixed at a temperature of 20° C. or higher prior to applying the odor control solution to the substrate to form a dispersion containing a complex of the cyclodextrin and the odor control compound.

9. The substrate of claim 2, wherein the odor control solution comprises from about 0.1 wt. % to about 14 wt. % of a stabilizing additive.

10. The substrate of claim 2, wherein the stabilizing additive is selected from the group consisting of corn syrup, glucose, high fructose corn syrup, trehalose, sucrose, sorbitol, amino acids, derivatives thereof, and combinations thereof.

11. The substrate of claim 2, wherein the stabilizing additive is selected from the group consisting of corn syrup, glucose, high fructose corn syrup, derivatives thereof, and combinations thereof, and wherein the odor control solution comprises: about 2 wt. % to about 10 wt. % of the stabilizing additive.

12. The substrate of claim 2, wherein the stabilizing additive is trehalose, and wherein the odor control solution comprises from about 0.1 wt. % to about 1.0 wt. % of the stabilizing additive.

13. The substrate according to claim 1, wherein the odor control solution further comprises glucose and / or corn syrup as a stabilizing additive, wherein the odor control solution comprises from about 2.4 wt. % to about 9.4 wt. % of the stabilizing additive, wherein the odor control solution comprises from about 3.5 moles to about 6 moles of the odor control compound per mole of the cyclodextrin, wherein the pH of the odor control solution is greater than 9 and less than 12.5, wherein the odor control compound is a mixture of compounds selected from the group consisting of a mixture of citral and coconut oil, a mixture of d-limonene and coconut oil, a mixture of citral and d-limonene, and a mixture of octanol and d-limonene, in, before applying the odor control solution to the substrate, mixing the odor control solution at a temperature of 20° C. or higher to form a dispersion containing a complex of the cyclodextrin and the odor control compound, and Wherein the moisture content of the substrate increases by less than 1.7 wt.% due to applying the odor control solution to the substrate.

14. An article comprising the substrate of claim 1.

15. A method for preparing an odor control substrate, comprising: a) providing a substrate, b) forming an odor control solution comprising: water, cyclodextrin, an odor control compound, a stabilizing additive, and optionally a polar organic solvent, wherein the odor control solution formed in b) is a dispersion containing a complex of the cyclodextrin and the odor control compound, c) applying said odour control solution to said substrate to obtain said odour control substrate, wherein, after c), the odor control substrate comprises at least 0.2 kg of the odor control compound per 1000 kg of the odor control substrate, and Wherein the moisture content of the substrate increases by less than 1.7 wt.% due to applying the odor control solution to the substrate.

16. A substrate comprising the odor control solution applied thereon, wherein the odor control solution comprises: water, cyclodextrin, an odor control compound, and a polar organic solvent, wherein said substrate comprises at least 0.2 kg of said odour control compound per 1000 kg of said substrate.

17. The substrate of claim 16, wherein the moisture content of the substrate increases by less than 1 wt.% as a result of applying the odor control solution to the substrate.

18. The substrate according to claim 16, wherein the substrate is: fluff pulp in the form of compressed sheets or air-laid fibers, synthetic or cellulosic fiber spunbond or carded nonwovens, woven fabrics or solid materials, or an absorbent article, in, When the substrate is a solid material, the solid material is selected from the group consisting of polymer foam, leather and plastic film, and Wherein, the substrate material is the absorbent product, and the absorbent product is an adult incontinence control pad, a feminine hygiene pad, a pull-on pants, an adult underwear, a baby diaper or a mattress.

19. The substrate according to claim 16, wherein the polar organic solvent is selected from the group consisting of glycerol, propylene glycol, polypropylene glycol, polyethylene glycol, and mixtures thereof.

20. The substrate of claim 16, wherein the cyclodextrin is unsubstituted or substituted α-, β-, or γ-cyclodextrin.

21. The substrate of claim 16, wherein the odor control compound is at least one of: Essential oils selected from the group consisting of citral, limonene, caprylic alcohol, lavender, geranium, grapefruit, linalool, citronellol, linalyl acetate, geraniol, eugenol, fluoroacetate, cardamom, eucalyptus, juniper berry, lavender, lemon verbena, lemongrass, patchouli, rose, spearmint, tea tree, oregano, persimmon, and mixtures thereof, Plant extracts, Odor-controlling substances selected from the group consisting of benzaldehyde, cinnamaldehyde, privetaldehyde, anthocyanin aldehyde and mixtures thereof, or An antibacterial substance selected from the group consisting of eucalyptus, lavender, thyme, peppermint, jade, cinnamon, clove, sage, tea tree oil, and mixtures thereof.

22. The substrate of claim 16, wherein the odor control solution comprises 1.5-1.75 moles of the odor control compound per mole of the cyclodextrin.

23. The substrate of claim 16, wherein the pH of the odor control solution is greater than or equal to 12.

0.

24. An article comprising the substrate of claim 16.

25. A method of preparing an odor control substrate, comprising: a) providing a substrate, b) applying an odour control solution to said substrate to obtain said odour control substrate, wherein the odor control solution comprises a polar organic solvent, water, cyclodextrin and an odor control compound, and wherein after b), said odour control substrate comprises at least 0.2 kg of said odour control compound per 1000 kg of said odour control substrate.

26. The method of claim 25, wherein applying the odor control solution to the substrate in b) increases the moisture content of the substrate by less than 1 wt.%.

27. The method of claim 25, wherein the odor control solution comprises 1.5 to 1.75 moles of the odor control compound per mole of the cyclodextrin.

28. The method of claim 25, wherein the pH of the odor control solution is greater than or equal to 12.0.

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