Absorbent articles and methods of making the same

Abstract

The present invention relates to an absorbent article and a method of manufacturing the same. A single-ply absorbent article is disclosed comprising a nonwoven first layer; a nonwoven third layer; a nonwoven second layer between the first layer and the third layer; and wherein the single-ply absorbent article has a first absorbency measure in a first delaminated state and a second absorbency measure in a second delaminated state, wherein the first absorbency measure is less than the second absorbency measure, and the first delaminated state is less than the second delaminated state.

Description

[0001] This application is a divisional application of application number 2020800667381, filed on October 21, 2020, entitled "Absorbent Article and Method for Manufacturing the Same".

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 62 / 923826, filed October 21, 2019, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to absorbent articles and methods for manufacturing them, and more particularly to a single-layer sheet, a multi-layer absorbent article, and methods for manufacturing them. Background Technology

[0004] Absorbency is a crucial property in many tissue products such as facial tissues, toilet paper, paper towels, and industrial wipes. Traditionally, increased absorbency has been achieved, for example, by manufacturing multi-layer sheets. However, manufacturing multi-layer sheets increases product complexity and cost. Summary of the Invention

[0005] Generally, this disclosure relates to a single-layer, multi-layer absorbent article. Generally, one aspect of the subject matter described in this specification can be implemented in an article comprising: a nonwoven first layer; a nonwoven third layer; a nonwoven second layer, the nonwoven second layer being located between the first and third layers; and wherein the single-layer absorbent article has a first absorbency measure in a first layered state and a second absorbency measure in a second layered state, wherein the first absorbency measure is less than the second absorbency measure, and the first layered state is less than the second layered state. In some embodiments, the article may comprise only three layers. Other embodiments of this aspect include corresponding methods.

[0006] Another aspect of the subject matter described in this specification can be implemented in an article of manufacture comprising: a single-layer absorbent article comprising a nonwoven first layer; a nonwoven second layer adjacent to the first layer; and wherein the single-layer absorbent article has a first absorbency measure in a first layered state and a second absorbency measure greater than the first absorbency measure in a second layered state greater than the first absorbency measure. In some embodiments, the article may comprise only two layers. Other embodiments of this aspect include corresponding methods.

[0007] Specific embodiments of the subject matter described in this specification can be implemented to achieve one or more of the following advantages. For example, by designing controlled measurements of the layering between given layers of a single-layer sheet product, single-layer and multi-layer products with the absorbency of a double-layer sheet product can be prepared without the complexity or cost of manufacturing a double-layer sheet. This also allows for the packaging and transportation benefits of single-layer sheets (e.g., smaller transport volumes) relative to double-layer sheet products, which often require a larger transport volume per product than their single-layer sheet counterparts (and therefore are more expensive).

[0008] The accompanying drawings and the following description illustrate details of one or more implementations of the subject matter described herein. Other features, aspects, and advantages of the subject matter will become apparent from the description, drawings, and claims. Attached Figure Description

[0009] Figure 1 This is an exemplary representation of the cross-section of a single-layer sheet or a three-layer absorbent article in the first layered state.

[0010] Figure 2 It is in the second layer state. Figure 1 An exemplary representation of the cross-section of an absorbent article.

[0011] Figure 3 This is a schematic diagram of an exemplary process for preparing single-layer sheets and multilayer absorbent products.

[0012] Figure 4 This is an exemplary representation of the cross-section of a single-layer or double-layer absorbent article.

[0013] The repeated use of reference numerals in this specification and drawings is intended to represent the same or similar features or elements of the invention. Detailed Implementation

[0014] This disclosure generally relates to single-ply and one-ply absorbent articles designed to be layered in a controlled manner to increase absorbency. In some embodiments, the single-ply and one-ply absorbent articles are three-layer structures having a top layer separated from the middle layer and the bottom layer, wherein the absorbent article is a foam-formed product, as described in more detail below. The absorbent article is formed in such a way that the top layer is loosely bonded to the middle layer, and the bottom layer is loosely bonded to the middle layer, to promote controlled layering of the top and bottom layers with the middle layer (e.g., the top and bottom layers are loosely hydrogen-bonded to the middle layer). For example, when a user operates the absorbent article to absorb water from the user's hand, one or more layers of the absorbent article are designed to layer in response to agitation or manipulation during the hand-drying process.

[0015] In this way, voids (e.g., open spaces between fibers or fiber bundles) are created, for example, between the top and bottom layers and intermediate layers. These voids increase the absorbency of the absorbent article compared to the absorbency of the article before the voids were created. See below for reference. Figure 1 The layering and improved single-layer and multi-layer absorbent products of this design will be discussed in more detail.

[0016] Figure 1 This is an exemplary representation of a cross-section of a single-layer sheet, three-layer absorbent article 100 in its first layered state. More specifically, the three-layer article has a first nonwoven layer 102, a second nonwoven layer 104, and a third nonwoven layer 106. A nonwoven layer is a layer having a sandwich structure but not in an identifiable manner (such as in a knitted layer) of single fibers or threads. Nonwoven layers can be formed by many methods, such as, for example, meltblown, spunbond, air-spun, co-forming, bonded carding web forming, and foam forming, as described in more detail below.

[0017] Absorbent article 100 may be, for example, a wipe, a wiper, a towel, tissue, or a component of a larger absorbent structure (such as a diaper or other personal care product). The performance of absorbent article 100 may be quantified by various measures, such as absorbency. The absorbency measure (A) reflects how much liquid the absorbent article can retain on a relative basis and is defined, for example, according to Equation 1 below:

[0018]

[0019] "Wet weight" refers to the weight (in grams) of the absorbent product after it has become saturated with water, while "dry weight" refers to the weight (in grams) of the absorbent product in a dry state (i.e., without absorbing water except through ambient / humidity conditions).

[0020] As described above, the absorbent article 100 is designed to layer in response to certain conditions, such as mechanical manipulation during dispensing or when a user operates the article to dry his / her hands, to increase its absorbency. The lamination strength between the layers must ensure that it remains intact during processing and winding (e.g., during the manufacture and packaging of the article) and during unfolding operations in conversion processes (e.g., during the process of converting the article into a form for sale to the end user). Therefore, the absorbent article 100 has a first layered state corresponding to a first absorbency measure and a second layered state corresponding to a second absorbency measure, wherein the first absorbency measure is less than the second absorbency measure (i.e., the "A" of the first absorbency measure from Equation 1 is less than the "A" of the second absorbency measure from Equation 1) and the first layered state is less than the second layered state.

[0021] The first layering state being less than the second layering state means that the level or amount of layering or separation between the first layer 102 and the second layer 104 in the first layering state and / or the level or amount of layering or separation between the third layer 106 and the second layer 104 in the second layering state is less than (or not equal to) the level or amount of layering or separation between the first layer 102 and the second layer 104 in the second layering state and / or the level or amount of layering or separation between the third layer 106 and the second layer 104. This is in Figure 1 and Figure 2 The differences between them are shown in the figure, where Figure 2 This is an exemplary representation of a cross-section of the absorbent article 100 in a second layered state, and shows the voids 108 created by the layering. Figure 2 The voids 108 represent layered regions where the corresponding surfaces of the first layer 102 and the third layer 106 have separated from the second layer 104, leaving open cavities (i.e., voids 108). It is believed that these voids 108 allow for increased absorbency of the article 100 in the second layered state compared to the first layered state.

[0022] More generally, the first layered state may include a state or condition with no or little (intentional) layering, and the second layered state is defined relative to the first layered state such that the second layered state is simply a state with a greater degree of layering (or layer separation) than the first layered state.

[0023] A series of experiments were conducted to demonstrate the effect of controlled stratification in single-layer and multi-layer absorbent products, as described below.

[0024] First-level state test – Each sample is collected from the production process without any intentional attempt to cause stratification or interference with the sample beyond normal handling procedures and practices.

[0025] For each sample, cut a one-square-inch piece of material and weigh it to obtain the dry weight of Equation 1 above. Next, fully immerse the sample in water for fifteen seconds, then remove it and hang it from one corner, allowing it to drip dry for fifteen seconds. Then, touch a piece of blotting paper to the lowest corner of the sample to remove any water droplets hanging on that corner. Finally, weigh the wet sample to determine its wet weight of Equation 1.

[0026] Second layer state

[0027] For each sample, a one-square-inch piece of material is cut and weighed to obtain the dry weight of Equation 1. The sample is then folded in half three times (each time along its longest dimension) and then unfolded—this folding and unfolding operation (e.g., applying a delamination force) results in a second delamination state. Next, the sample is fully immersed in water for fifteen seconds, and then removed and hung from one corner to drip dry for fifteen seconds. A piece of blotting paper is then touched to the lowest corner of the sample to remove any water droplets hanging on that corner. Finally, the wet sample is weighed to determine its wet weight of Equation 1.

[0028] sample

[0029] Six samples were tested according to the above testing method. Sample A is the single-layer sheet / triple-layer absorbent product 100 of the present invention, Sample B is a KLEENEX single-layer sheet towel (50606), Sample C is a KLEENEX double-layer sheet towel (46321), Sample D is a TORK premium single-layer sheet towel (290095), Sample E is a Georgia-Pacific Pro enMotion single-layer sheet towel (89460), and Sample F is a TORK premium double-layer sheet towel (290019). For each sample, ten embodiments of that sample were tested, as reflected in the following results.

[0030] result

[0031] Sample A:

[0032]

[0033] Table 1

[0034] As shown in Table 1, for the first embodiment of sample A, the first absorbency measure of the first stratified state is 8.14, and the second absorbency measure of the second absorbent state is 12.40. For the second embodiment of sample A, the first absorbency measure of the first stratified state is 7.88, and the second absorbency measure of the second absorbent state is 9.83. Continuing, for the tenth embodiment of sample A, the first absorbency measure of the first stratified state is 9.83, and the second absorbency measure of the second absorbent state is 11.13.

[0035] The average first absorbency measure (A) for all ten embodiments of Sample A is 8.02. The average second absorbency measure (A) for all ten embodiments of Sample A is 10.73. For all ten embodiments of Sample A, the increase between the first and second absorbency measures is thirty-four percent. Therefore, the effect of moving article 100 from the first stratified state to the second stratified state results in an increase in absorbency (A) of thirty-four percent. As described above, it is believed that being in the second stratified state provides article 100 with a means of trapping liquid, for example, between the first layer 102 and the third layer 106, through the additional void volume (e.g., void 108) created by the greater degree of stratification, resulting in the greater absorbency as shown in Table 1.

[0036] Sample B:

[0037]

[0038] Table 2

[0039] As shown in Table 2, for the first embodiment of Sample B, the first absorbency measure of the first stratified state is 5.40, and the second absorbency measure of the second absorbent state is 5.00. For the second embodiment of Sample B, the first absorbency measure of the first stratified state is 6.00, and the second absorbency measure of the second absorbent state is 5.00. Continuing, for the tenth embodiment of Sample B, the first absorbency measure of the first stratified state is 6.40, and the second absorbency measure of the second absorbent state is 6.00. The average value of the first absorbency measure (A) for all ten embodiments of Sample B is 5.91. The average value of the second absorbency measure (A) for all ten embodiments of Sample B is 5.47. For all ten embodiments of Sample B, the value between the first and second absorbency measures decreases by eight percent. It is believed that the process of "manipulating" Sample B to move to the collapsed void volume in the second stratified state, thereby reducing the void volume, is effective in terms of absorbency.

[0040] Sample C:

[0041]

[0042] Table 3

[0043] As shown in Table 3, for the first embodiment of sample C, the first absorbency measure of the first stratified state is 9.14, and the second absorbency measure of the second absorbent state is 8.86. For the second embodiment of sample C, the first absorbency measure of the first stratified state is 11.17, and the second absorbency measure of the second absorbent state is 11.0. Continuing, for the tenth embodiment of sample C, the first absorbency measure of the first stratified state is 10.50, and the second absorbency measure of the second absorbent state is 9.25. The average value of the first absorbency measure (A) for all ten embodiments of sample C is 10.20. The average value of the second absorbency measure (A) for all ten embodiments of sample C is 9.48. For all ten embodiments of sample C, the value between the first and second absorbency measures decreases by seven percent. It is believed that the process of "manipulating" sample C to move to the collapsed void volume in the second stratified state, thereby reducing the void volume, is effective absorbency.

[0044] Sample D:

[0045]

[0046] Table 4

[0047] As shown in Table 4, for the first embodiment of sample D, the first absorbency measure of the first stratified state is 5.40, and the second absorbency measure of the second absorbency state is 6.50. For the second embodiment of sample D, the first absorbency measure of the first stratified state is 4.83, and the second absorbency measure of the second absorbency state is 4.86. Continuing, for the tenth embodiment of sample D, the first absorbency measure of the first stratified state is 4.5, and the second absorbency measure of the second absorbency state is 6.00. The average value of the first absorbency measure (A) for all ten embodiments of sample D is 5.73. The average value of the second absorbency measure (A) for all ten embodiments of sample D is 5.53. For all ten embodiments of sample D, the value between the first and second absorbency measures decreases by three percent. It is believed that the process of "manipulating" sample D to move to the collapsed void volume in the second stratified state, thereby reducing the void volume, is the absorption effect.

[0048] Sample E:

[0049]

[0050] Table 5

[0051] As shown in Table 5, for the first embodiment of Sample E, the first absorbency measure of the first stratified state is 4.44, and the second absorbency measure of the second absorbent state is 4.50. For the second embodiment of Sample E, the first absorbency measure of the first stratified state is 4.10, and the second absorbency measure of the second absorbent state is 4.25. Continuing, for the tenth embodiment of Sample E, the first absorbency measure of the first stratified state is 4.11, and the second absorbency measure of the second absorbent state is 4.14. The average value of the first absorbency measure (A) for all ten embodiments of Sample E is 4.33. The average value of the second absorbency measure (A) for all ten embodiments of Sample E is 4.32. For all ten embodiments of Sample E, the values ​​between the first and second absorbency measures remain the same.

[0052] Sample F:

[0053]

[0054] Table 6

[0055] As shown in Table 6, for the first embodiment of sample F, the first absorbency measure of the first stratified state is 6.00, and the second absorbency measure of the second absorbent state is 6.17. For the second embodiment of sample F, the first absorbency measure of the first stratified state is 5.50, and the second absorbency measure of the second absorbent state is 5.43. Continuing, for the tenth embodiment of sample F, the first absorbency measure of the first stratified state is 5.63, and the second absorbency measure of the second absorbent state is 6.17. The average value of the first absorbency measure (A) for all ten embodiments of sample F is 5.93. The average value of the second absorbency measure (A) for all ten embodiments of sample F is 6.02. For all ten embodiments of sample F, the value between the first and second absorbency measures increases slightly by two percent, which can be attributed to test tolerances.

[0056] Therefore, the test results clearly demonstrate that the partial stratification of the absorbent article 100 in its second stratified state significantly increases its absorbency, up to the level of some bilayer products and even higher. For example, the second absorbency measure is approximately 5% to 34% greater than the first absorbency measure, or approximately 10% to 34% greater than the first absorbency measure, or approximately 20% to 30% greater than the first absorbency measure, or at least 10% greater than the first absorbency measure, as shown in the table above.

[0057] However, complete or full delamination should be avoided, as this would cause the multilayer absorbent to separate into individual layers and compromise the user's cleaning or drying experience. Bonding and adhesion between layers can be controlled in various ways. For example, pulp fibers with varying degrees of cross-linking or chemical treatment with various release agents can be used to interfere with fiber-to-fiber bonding in a manner that controls lamination strength. Unbonded or low-bonding synthetic fibers and / or granules can also be used in the second layer 104 to control the lamination strength between the first layer 102 and the third layer 106.

[0058] In some embodiments, the amount of layering can be selected such that the absorbent article 100 reaches a second layered state through the typical operation of a user drying his / her hands and / or dispensing the article via a dispenser. For example, if article 100 is a paper towel, feeding the paper towel via the dispensing mechanism of a paper towel dispenser is sufficient to bring article 100 to a second layered state and (therefore) have a second absorbency measure for better drying of the user's hands.

[0059] In some embodiments, article 100 has a first layer 102 and a third layer 106 made of northern cork pulp and a second layer 104 made of debonded cellulose fibers. As described below, the nonwoven layers 102, 104 and 106 may be made of other fibers.

[0060] In some embodiments, article 100 may be a foam-formed product. A foam-formed product is a product formed from a suspension comprising a mixture of solids, liquids, and dispersed bubbles. The solids in the suspension of the foam-formed product may include solid particles, such as natural and / or synthetic fibers. Other solids that may be added to the suspension include, for example, superabsorbent materials such as activated carbon, microencapsulated active ingredients, calcium carbonate, and titanium dioxide. The liquids in the suspension of the foam-formed product may, for example, include water. In some embodiments, a surfactant may, for example, be used in the suspension. The suspension of the foam-formed product may, for example, include air as a gaseous component for forming dispersed bubbles. In some embodiments, the air content in the suspension may range from about 20% to about 95% or from about 30% to about 80%. In some embodiments, the bubbles may include a substitute gas or an additional gas.

[0061] Figure 3 This is a schematic diagram illustrating an exemplary process for preparing single-layer sheets and multi-layer absorbent articles, such as products formed from the aforementioned foam. In some embodiments, for example, in Figure 3In one embodiment of the process structure described herein, foam is first formed by combining water with a foaming agent. The foaming agent may, for example, contain any suitable surfactant. In one embodiment, the foaming agent may, for example, contain sodium lauryl sulfate, also known as sodium lauryl polyoxyethylene ether sulfate or sodium lauryl ether sulfate. Other foaming agents include sodium dodecyl sulfate or ammonium lauryl sulfate. In other embodiments, the foaming agent may contain any suitable cationic and / or amphoteric surfactant. For example, other foaming agents include fatty acid amines, amides, amine oxides, quaternary ammonium compounds of fatty acids, etc.

[0062] In some embodiments, the foaming agent is typically combined with water in an amount greater than about 2% by weight, for example greater than about 5% by weight, for example greater than about 10% by weight, for example greater than about 15% by weight. One or more foaming agents are typically present in an amount less than about 50% by weight, for example less than about 40% by weight, for example less than about 30% by weight, for example less than about 20% by weight.

[0063] Once the foaming agent and water are combined, the mixture is blended or otherwise subjected to forces capable of forming foam. Foam generally refers to a porous matrix, which is an aggregate of hollow units or bubbles that can connect to each other to form channels or capillaries.

[0064] Foam density can vary depending on the specific application and various factors, including the fiber formulation used. In some embodiments, for example, the foam density can be greater than about 200 g / L, for example greater than about 250 g / L, for example greater than about 300 g / L. Foam density is typically less than about 600 g / L, for example less than about 500 g / L, for example less than about 400 g / L, for example less than about 350 g / L. In some embodiments, for example, lower density foams are used, typically less than about 350 g / L, for example less than about 340 g / L, for example less than about 330 g / L. The air content of the foam will typically be greater than about 30%, for example greater than about 50%, for example greater than about 60%. The air content is typically less than about 80% by volume, for example less than about 70% by volume, for example less than about 65% by volume.

[0065] Once the foam is formed, it is combined with fiber ingredients. Generally, any fiber capable of producing tissue paper or paper webs or other similar types of nonwoven fabrics according to this disclosure can be used.

[0066] Fibers suitable for preparing nonwoven layers may include a variety of natural or synthetic cellulose fibers, including but not limited to non-wood fibers such as cotton, Manila hemp, kenaf, Indian grass, flax, thatch, straw, jute, bagasse, milkweed, and pineapple leaf fibers; and woody or pulp fibers, such as those obtained from broadleaf and coniferous trees, including softwood fibers such as northern and southern softwood kraft paper fibers; and hardwood fibers such as eucalyptus, maple, birch, and aspen. Pulp fibers can be prepared in high-yield or low-yield forms and can be pulped by any known method (including kraft paper, sulfite, high-yield pulping methods) and other known pulping methods. Fibers prepared by organic solvent pulping methods may also be used.

[0067] A portion of the fiber (such as up to 50% or less by dry weight, or about 5% to about 30% by dry weight) may be synthetic fibers, such as rayon, polyolefin fibers, polyester fibers, bicomponent core-sheath fibers, multicomponent binder fibers, etc. An example polyethylene fiber is Fybrel® from Minifibers, Inc. (Jackson City, Tenn.). Any known bleaching method may be used. Synthetic cellulose fiber types include all varieties of rayon and other fibers derived from viscose or chemically modified cellulose. Chemically treated natural cellulose fibers may be used, such as mercerized pulp; chemically hardened, debonded, or cross-linked fibers; or sulfonated fibers. To achieve good mechanical properties when using papermaking fibers, it may be desirable for the fibers to be relatively undamaged and largely unrefined or only slightly refined. While regenerated fibers may be used, virgin fibers are generally available due to their mechanical properties and lack of contaminants. Mercerized fibers, regenerated cellulose fibers, cellulose produced by microorganisms, rayon, and other cellulose materials or cellulose derivatives may be used. Suitable papermaking fibers may also include regenerated fibers, virgin fibers, or mixtures thereof. In some embodiments that enable high bulk and good compression properties, the fiber may have a Canadian standard freeness of at least 200, more specifically at least 300, more specifically at least 400 and most specifically at least 500.

[0068] Other papermaking fibers that can be used in this disclosure include secondary paper or recycled fibers and high-yield fibers. High-yield pulp fibers are those papermaking fibers produced by pulping processes that provide a yield of about 65% or more, more specifically about 75% or more, and even more specifically about 75% to about 95%. Yield is the amount of processed fiber obtained as a percentage of the initial wood mass. Such pulping processes include bleached chemothermal-mechanical pulp (BCTMP), chemothermal-mechanical pulp (CTMP), pressure / pressure thermomechanical pulp (PTMP), thermomechanical pulp (TMP), thermomechanical chemical pulp (TMCP), high-yield nitrite pulp, and high-yield kraft pulp, all of which result in fibers with high levels of lignin. High-yield fibers are known for their stiffness relative to typical chemically pulped fibers in both dry and wet states.

[0069] Thin paper webs can also be formed without significant internal fiber-to-fiber bonding strength. In this regard, the fiber formulation used to form the base web can be treated with a chemical detackifier. The detackifier can be added to the foamed fiber slurry during the pulping process or directly to the headbox. Suitable detackifiers that can be used in this disclosure include cationic detackifiers, such as aliphatic dialkyl quaternary ammonium salts, monoaliphatic alkyl tertiary ammonium salts, primary amine salts, imidazoline quaternary salts, organosilicon quaternary salts, and unsaturated aliphatic alkyl ammonium salts. Other suitable detackifiers are disclosed in U.S. Patent No. 5,529,665 to Kaun, which is incorporated herein by reference. Specifically, Kaun discloses the use of cationic organosilicon compositions as detackifiers. Any of these materials can be used to establish the correct level of lamination strength between different layers in article 100.

[0070] In one embodiment, the detacking agent used in the process of this disclosure is an organic quaternary ammonium chloride, and more specifically, an organosilicon amine salt of quaternary ammonium chloride. For example, the detacking agent may be PROSOFT.RTM. TQ1003 sold by Solenis Corporation. The detacking agent may be added to the fiber slurry in an amount of about 1 kg / ton of fiber to about 10 kg / ton of fiber present in the slurry.

[0071] In an alternative embodiment, the detacker may be an imidazoline-based agent. Imidazolline-based detackers may be obtained, for example, from Witco Corporation. Imidazolline-based detackers may be added in amounts ranging from 2.0 to about 15 kg per metric ton.

[0072] Other optional chemical additives may also be added to the aqueous papermaking ingredients or the initial web formed to impart additional benefits to the product and process. The following materials are examples of other chemicals that can be applied to the web. These chemicals are examples and are not intended to limit the scope of the invention. Such chemicals can be added at any time during the papermaking process.

[0073] Other types of chemicals that can be added to the paper web include, but are not limited to, absorbent additives such as low molecular weight polyethylene glycol and polyhydroxy compounds such as glycerin and propylene glycol, which are typically in the form of cationic, anionic, or nonionic surfactants, humectants, and plasticizers. Materials that provide skin health benefits, such as mineral oil, aloe vera extract, vitamin E, silicones, and general emulsions, can also be incorporated into the finished product.

[0074] like Figure 3 Specifically, the foamed fiber suspension of the first layer 102 can be fed into tank 12a, the foamed fiber suspension of the second layer 104 can be fed into tank 12b, and the foamed fiber suspension of the third layer 106 can be fed into tank 12c. All three suspensions are then fed into a three-chamber headbox 10, allowing the three foamed suspensions to be combined in a manner that causes very small layer-to-layer mixing of the fibers in the suspension. From the headbox 10, the foamed fiber suspension is fed onto a continuously moving forming fabric 26 supported and driven by rollers 28 to form a single-layer sheet, three-layer article 100.

[0075] Because the three layers 102, 104, and 106 are foam-formed, they are highly homogeneous and exhibit limited layer-to-layer fiber mixing or entanglement, which helps to promote controlled stratification (since high layer-to-layer fiber mixing reduces the ability to stratify). As described elsewhere, complete layer-to-layer stratification is undesirable; therefore, fiber selection, layering techniques, fiber treatment, and post-forming processes (e.g., post-headbox bonding) are tools for selectively applying the desired precise amount of stratification to achieve the increased absorbency between the first and second stratification states described herein.

[0076] Once the article 100 is formed on the forming fabric 26, the article 100 can be conveyed downstream and dehydrated, for example. The method may include, for example, multiple vacuum devices 16, such as vacuum chambers and vacuum rollers. The vacuum chambers 16 help remove moisture from the newly formed article 100. The newly formed article 100 can then be conveyed downstream from the forming fabric 26 and dried, for example, in a ventilated dryer.

[0077] The basis weight of the absorbent article 100 prepared according to this disclosure can vary depending on the final product. For example, this method can be used to produce paper towels, industrial wipes, etc. Generally, the basis weight of these products can vary from about 20 gsm to about 100 gsm. On the other hand, for paper towels, the basis weight can be in the range of about 20 gsm to about 65 gsm.

[0078] As described above, absorbent article 100 provides, for example, the benefits of a bilayer sheet without some of the manufacturing complexities associated with preparing a bilayer sheet product. For comparative purposes, using Figure 3 The single-layer sheet method, and the double-layer sheet method, involve (1) preparing a first single-layer sheet (having one or more layers), (2) preparing a second single-layer sheet (having one or more layers), and then (3) bonding the two single-layer sheets together, for example by heat, ultrasound, or adhesive bonding. The single-layer sheet article 100 described herein avoids the cost and complexity of steps (2) and (3), but is comparable to or better than some double-layer sheet materials as shown in the table above.

[0079] In some implementations, such as Figure 4 As shown, the monolayer absorbent article 400 comprises (e.g., only) two layers. Specifically, a nonwoven first layer 402 and a nonwoven second layer 404 adjacent to (e.g., at least partially in contact with) the first layer 402. The monolayer absorbent article 400 has a first absorbency measure in a first layered state and a second absorbency measure in a second layered state. The first absorbency measure is less than the second absorbency measure, and the first layered state is less than the second layered state. In the relevant sections, article 400 operates similarly to article 100. The two layers 402, 404 are formed (e.g., foam formation) and / or constituted to control the amount of layer-to-layer adhesion and bonding, such that the layers partially delaminate in response to certain conditions (e.g., user's hands drying), resulting in voids at the layer-to-layer interfaces, thereby leading to increased absorbency as demonstrated in the table above.

[0080] Implementation

[0081] Embodiment 1. A single-layer sheet absorbent article, the single-layer sheet absorbent article comprising a nonwoven first layer; a nonwoven third layer; a nonwoven second layer, the nonwoven second layer being located between the first layer and the third layer; and wherein the single-layer sheet absorbent article has a first absorbency measure in a first layered state and a second absorbency measure in a second layered state, wherein the first absorbency measure is less than the second absorbency measure, and the first layered state is less than the second layered state.

[0082] Embodiment 2. The single-layer sheet absorbent article as described in Embodiment 1, wherein at least one of the first layer, the second layer, and the third layer is formed of foam.

[0083] Embodiment 3. A single-layer sheet absorbent article as described in Embodiment 2, wherein each of the first layer, the second layer, and the third layer is formed of foam.

[0084] Embodiment 4. A single-layer absorbent article as described in any of the preceding embodiments, wherein the second layer comprises debonded cellulose fibers.

[0085] Embodiment 5. A single-layer sheet absorbent article as described in any of the preceding embodiments, wherein the first layer comprises northern softwood pulp.

[0086] Embodiment 6. A single-layer absorbent article as described in any of the preceding embodiments, wherein the second absorbency measure is approximately 5% to 34% higher than the first absorbency measure.

[0087] Embodiment 7. A single-layer absorbent article as described in any one of Embodiments 1 to 5, wherein the second absorbency measure is approximately 10% to 34% of the first absorbency measure.

[0088] Embodiment 8. A single-layer absorbent article as described in any one of Embodiments 1 to 5, wherein the second absorbency measure is approximately 20% to 30% greater than the first absorbency measure.

[0089] Embodiment 9. A single-layer absorbent article as described in any one of Embodiments 1 to 5, wherein the second absorbency measure is at least 10 percent greater than the first absorbency measure.

[0090] Embodiment 10. A single-layer sheet absorbent article, the single-layer sheet absorbent article comprising a nonwoven first layer; a nonwoven second layer adjacent to the first layer; and wherein the single-layer sheet absorbent article has a first absorbency measure in a first layered state and a second absorbency measure in a second layered state, wherein the first absorbency measure is less than the second absorbency measure, and the first layered state is less than the second layered state.

[0091] Embodiment 11. A single-layer sheet absorbent article as described in Embodiment 10, wherein at least one of the first layer and the second layer is formed of foam.

[0092] Embodiment 12. A single-layer sheet absorbent article as described in Embodiment 11, wherein each of the first layer and the second layer is foam-formed.

[0093] Embodiment 13. The single-layer sheet absorbent article as described in Embodiment 12, wherein the second absorbency measure is approximately 5% to 34% greater than the first absorbency measure.

[0094] Embodiment 14. A single-layer absorbent article as described in any one of Embodiments 10 to 12, wherein the second absorbency measure is approximately 10% to 34% of the first absorbency measure.

[0095] Embodiment 15. A single-layer sheet absorbent article as described in any one of Embodiments 10 to 12, wherein the second absorbency measure is approximately 20% to 30% greater than the first absorbency measure.

[0096] Embodiment 16. A single-layer sheet absorbent article as described in any one of Embodiments 10 to 12, wherein the second absorbency measure is at least 10 percent greater than the first absorbency measure.

[0097] While this specification contains numerous specific implementation details, these details should not be construed as limiting the scope of any invention or claimable content, but rather as descriptions of features specific to particular embodiments of a particular invention. Certain features described in this specification within the context of individual embodiments may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented individually or in any suitable sub-combination in multiple embodiments. Furthermore, although features may be described above as functioning in certain combinations, or even initially claimed, one or more features from a claimed combination may be removed from the combination in some circumstances, and a claimed combination may be for a sub-combination or a variation thereof.

[0098] Similarly, although the operations are depicted in a specific order in the accompanying drawings, this should not be construed as requiring such operations to be performed in the specific order shown or sequentially, or that all shown operations be performed to achieve the desired result. In some cases, multitasking and parallel processing can be advantageous. Furthermore, the separation of various system components in the above embodiments should not be construed as requiring such separation in all embodiments.

[0099] This written description does not limit the invention to the precise terminology used. Therefore, although the invention has been described in detail with reference to the above examples, those skilled in the art can make changes, modifications, and variations to these examples without departing from the scope of the invention.

Claims

1. A single-layer absorbent article, the single-layer absorbent article comprising: Nonwoven first layer; Nonwoven third layer; A nonwoven second layer, wherein the nonwoven second layer is located between the first layer and the third layer; and The single-layer sheet absorbent article has a first absorbency measure in a first layered state and a second absorbency measure in a second layered state, wherein the first absorbency measure is less than the second absorbency measure, and the first layered state is less than the second layered state.

2. The single-layer absorbent article of claim 1, wherein at least one of the first layer, the second layer and the third layer is formed of foam.

3. The single-layer absorbent article of claim 2, wherein each of the first layer, the second layer and the third layer is formed of foam.

4. The single-layer absorbent article of claim 1, wherein the second layer comprises debonded cellulose fibers.

5. The single-layer absorbent article of claim 1, wherein the first layer comprises northern cork pulp.

6. The single-layer absorbent article of claim 1, wherein the second absorbency measure is approximately 5% to 34% greater than the first absorbency measure.

7. The single-layer absorbent article of claim 1, wherein the second absorbency measure is approximately 10% to 34% greater than the first absorbency measure.

8. The single-layer absorbent article of claim 1, wherein the second absorbency measure is approximately 20% to 30% greater than the first absorbency measure.

9. The single-layer absorbent article of claim 1, wherein the second absorbency measure is at least 10 percent greater than the first absorbency measure.

10. A single-layer absorbent article, the single-layer absorbent article comprising: Nonwoven first layer; A nonwoven second layer, wherein the nonwoven second layer is adjacent to the first layer; and The single-layer sheet absorbent article has a first absorbency measure in a first layered state and a second absorbency measure in a second layered state, wherein the first absorbency measure is less than the second absorbency measure, and the first layered state is less than the second layered state.

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