Absorbent system and absorbent article comprising same

Abstract

An absorbent system comprising: a first absorbent core layer made of cellulose and a superabsorbent material; a second absorbent core layer disposed over the first absorbent core layer, made of a synthetic material and a superabsorbent material, and having folded ends such that the second absorbent core layer has a C-shape; the first liquid collection distribution layer is arranged on the second absorption core layer; the core cladding layer is arranged around the first absorption core layer, the second absorption core layer and the first liquid collection distribution layer; and the second liquid collection distribution layer is arranged on the core cladding layer.

Description

Technical Field

[0001] The present utility model generally relates to absorbent systems, and particularly to absorbent systems that can be used in hygienic absorbent articles. Background Art

[0002] Absorbent articles such as diapers, training pants, briefs, sanitary pads, and pantiliners have been manufactured and sold for many years. Generally speaking, these products can prevent accidental contact with body fluids or feces. These products usually include an absorbent core for holding fluids.

[0003] Traditional absorbent cores can be "preformed" from synthetic materials. In this context, the term "preformed" means that the core is made of synthetic materials and fixed to the absorbent article during the manufacturing process.

[0004] A well-known problem associated with preformed cores that use only synthetic carriers with embedded super-absorbent particles (SAP) is always related to the slow fluid intake rate. Even worse, preformed cores with channels perform poorly when the diaper is tilted because the fluid will quickly flow out of the channels due to gravity. This can be explained by the lack of cellulose fibers, which can contribute to capillary action, act as a temporary reservoir, and give the SAP time to do its job. Even when using traditional diaper cores, such as those using a mixture of cellulose and SAP, when the ratio of SAP increases, for example, exceeds 50%, it usually takes longer to absorb fluid compared to cores with a lower SAP ratio. When designing diapers for long-term use (e.g., those expected to be used overnight), it is important to increase the amount of SAP to a SAP ratio higher than 50%. This is because compared to cellulose, SAP can hold more fluid, such as urine, especially under pressure. In addition, a higher SAP ratio helps avoid a bulky core, which may be uncomfortable due to its excessive thickness and may even interfere with the normal walking of a baby in some cases, especially after the core has been saturated with urine.

[0005] To reduce early leakage, cores loaded with a higher SAP ratio require a special nonwoven material layer, which is known in the industry as ADL or Acquisition Distribution Layer (also referred to as the liquid collection and distribution layer in this article). The ADL is typically located between the absorbent core and the topsheet. The ADL is usually made of highloft polyester, which is typically 30 GSM to 120 GSM. More elastic ADL materials are generally preferred to assist in liquid distribution and keep the top surface as dry as possible. For high-performance absorbent cores, it is very important to avoid having a pool of liquid in the diaper at any time, as this can lead to early leakage, even if the urine volume is far below the product's expected retentive capacity. The ADL helps with liquid intake and also with capillary action to better utilize the absorbent material in the core, thus helping to avoid the formation of a pool of liquid.

[0006] If the ratio of SAP in the absorbent core increases, a greater weight of ADL (i.e., a higher basisweight) is required to compensate for the slower rate. For example, a diaper core with an SAP ratio of over 60 wt% would severely fail due to premature leakage if it did not use an ADL. On the other hand, if a diaper with a minimal amount of SAP (e.g., a diaper core with an SAP ratio of less than 10%) is used with an ADL (independent of using a higher basisweight), the ADL would be a complete waste of resources as it would not add value to an already fast core. However, in this case, the diaper core would have a very limited retentive capacity and no benefit in terms of rewetting. An effective balance needs to be achieved between the SAP ratio and the ADL basisweight (especially in the case of nonwoven ADL) to achieve optimal performance and avoid adding resources that no longer add value.

[0007] As a way to shorten the fluid acquisition time, Procter & Gamble recently developed a SAP printing technology that allows the production of absorbent cores with "channels". These channels are not made full length along the length of the core, but are interrupted about one-third of their length at both ends of the core to prevent liquid from flowing out of the channels and then leaking prematurely from the diaper. This can be an easily demonstrable problem when the diaper is at an inclined angle and full-length channels (i.e., channels without interruptions) are used. Once the SAP starts absorbing liquid, it swells and forms these channels. Procter & Gamble was one of the first companies in the Western world to manufacture a fluff-less core, except for a small amount of curled fibers and the ADL used on the printed SAP surface. Other manufacturers, such as Drylock Technologies, also developed a fluff-less core that was made in the shape of small pillows (combined with ultrasonic), but was quickly replaced by their own channel alternatives, using only a small amount of fluff. Ontex, Abena, and Kimberly-Clark quickly developed their own alternative versions of interrupted channels, each with a different configuration.

[0008] The interrupted channels shorten the acquisition time by allowing the liquid to move quickly along the channels (especially after the initial swelling of the SAP). Many manufacturers have had to fine-tune their own channels, for example, by changing the length of the channel interruptions and the distance to the edges, while they are also learning how to reduce early leakage.

[0009] As more and more companies try to use the concept of channels, they encounter the same problem that they initially encountered when producing 3D absorbent cores using three-dimensional drum former pockets. Diaper cores with channels must be registered, which means that every time the diaper machine is changed to a different diaper size, the absorbent core must also be changed. This not only increases the downtime, but also brings more adjustments and overall complexity to downstream production, increases waste, and reduces overall efficiency.

[0010] There are ongoing challenges in manufacturing high-performance absorbent products because it is necessary to balance the key performance of the product to achieve a comfortable experience for the wearer, while providing a more durable product without the risk of initial leakage. There are also ongoing challenges in manufacturing diaper absorbent cores with channels in terms of increasing overall manufacturing efficiency while reducing downtime and waste. Summary of the Invention

[0011] An absorbent system according to an exemplary embodiment of the present invention includes: a first absorbent core layer including cellulose and a superabsorbent material; a second absorbent core layer disposed above the first absorbent core layer, including a synthetic material and a superabsorbent material, and the second absorbent core layer has folded ends such that the second absorbent core layer has a C shape; a first liquid collection and distribution layer disposed above the second absorbent core layer; a core wrap layer disposed around the first absorbent core layer, the second absorbent core layer, and the first liquid collection and distribution layer; and a second liquid collection and distribution layer disposed above the core wrap layer.

[0012] In an exemplary embodiment, the second absorbent core layer includes a nonwoven layer disposed between two carrier layers.

[0013] In an exemplary embodiment, the carrier layer includes a spunbond material.

[0014] In an exemplary embodiment, the second absorbent core layer includes a channel formed between the ends.

[0015] In an exemplary embodiment, the first absorbent core layer includes a channel.

[0016] In an exemplary embodiment, the first absorbent core layer includes a first portion and a second portion, and the channel of the first absorbent core layer is formed by a space between the first portion and the second portion.

[0017] In an exemplary embodiment, the channel of the first absorbent core layer is formed by a portion of the second absorbent core layer having a reduced amount of superabsorbent material.

[0018] In an exemplary embodiment, the channel of the second absorbent core layer is formed by a portion of the second absorbent core layer having a reduced thickness.

[0019] In an exemplary embodiment, the first liquid collection and distribution layer is larger than the second liquid collection and distribution layer.

[0020] In an exemplary embodiment, the length that the second liquid collection and distribution layer extends is less than the full length of the absorbent system.

[0021] An absorbent article according to an exemplary embodiment of the present invention includes: An absorbent system according to an exemplary embodiment of the present invention includes: a first absorbent core layer including cellulose and a superabsorbent material; a second absorbent core layer disposed above the first absorbent core layer, including a synthetic material and a superabsorbent material, and the second absorbent core layer has folded ends such that the second absorbent core layer has a C shape; a first liquid collection and distribution layer disposed above the second absorbent core layer; a core wrap layer disposed around the first absorbent core layer, the second absorbent core layer, and the first liquid collection and distribution layer; and a second liquid collection and distribution layer disposed above the core wrap layer. Brief Description of the Drawings

[0022] Figure 1A is a cross-sectional view of an absorbent system according to an exemplary embodiment of the present invention;

[0023] Figure 1B is a cross-sectional view of an upper absorbent core layer according to an exemplary embodiment of the present invention;

[0024] Figure 2A is a cross-sectional view of an upper absorbent core layer according to an exemplary embodiment of the present invention; and

[0025] Figure 2B is a plan view of an upper absorbent core layer according to an exemplary embodiment of the present invention. Detailed Description

[0026] An absorbent system according to an exemplary embodiment of the present invention includes a primary core layer and a C-folded synthetic core layer disposed on top of the primary core layer. This unique structure provides enhanced performance parameters compared to traditional cores, including a lower leakage rate, a lower rewet amount under long-term use, and a high saline retention, as well as an optimized combination of these parameters.

[0027] As used herein, the term "absorbent core" refers to a material or combination of materials adapted to absorb, distribute, and store aqueous fluids such as water in urine, blood, menses, and body exudates. The absorbent core or inserts can be formed or cut from a web of absorbent material. The size and shape of the absorbent core can be varied to meet absorbency requirements and provide comfort to the wearer / user. The length of the absorbent core can be from about 20 cm to about 60 cm. The width of the absorbent core can be from about 4 cm to about 20 cm. When a second absorbent core is used, the size of the second absorbent core can be the same as the first absorbent core, or smaller or larger than the first absorbent core. Non-limiting examples of liquid-absorbent materials suitable for use as an absorbent core according to an exemplary embodiment of the present invention include: comminuted wood pulp, which is commonly referred to as "airfelt"; creped cellulose wadding; absorbent gelling materials, including superabsorbent polymers, such as hydrogel-forming polymeric gelling agents; chemically strengthened, modified, or crosslinked cellulose fibers; synthetic fibers, including crimped polyester fiber; tissue, including tissue wraps and tissue laminates; capillary channel fibers; absorbent foams; absorbent sponges; synthetic staple fibers; peat moss; or any equivalent material; or combinations thereof, as are well known in the art of manufacturing absorbent products such as sanitary napkins, pantiliners, incontinence pads, and the like. Based on the total weight of the absorbent material in the core, the amount of superabsorbent polymer in the absorbent core can be from about 20% to about 85% (by weight), from about 40% to about 80% (by weight), from about 50% to about 75% (by weight), or from about 60% to about 70% (by weight).

[0028] Figure 1AAn absorbent system according to an exemplary embodiment of the present invention is shown, which is generally indicated by reference numeral 1. The absorbent system 1 includes: a first absorbent core layer 10 (also referred to herein as a "lower absorbent core layer"); a second absorbent core layer 20 (also referred to herein as an "upper absorbent core layer") disposed above the first absorbent core layer 10; a first ADL layer 30 disposed above the second absorbent core layer 20; a core wrap 40 disposed around the first absorbent core layer 10, the second absorbent core layer 20, and the first ADL layer 30; and a second ADL layer 50 disposed above the core wrap 40 and the first ADL layer 30. One or more of these layers may be attached to each other by, for example, an adhesive.

[0029] The first absorbent core 10 is an absorbent core made of uniform blend of SAP and cellulose. The first absorbent core 10 can be a single sheet (unitary sheet), and can also be made by several independent sheets arranged side by side. In an exemplary embodiment, the first absorbent core 10 comprises a middle channel 12, which is formed by the interval (separation) between two pieces of materials arranged side by side that for example partially or completely pass through the opening formed by the first core 10, constitute the first absorbent core 10, and / or the first absorbent core 10 without SAP or comprising a small amount of SAP. When the first absorbent core 10 expands because of fluid absorption, channel 12 is surrounded by the material that expands more than channel 12, and this will strengthen fluid absorption characteristics, thereby further improves collection speed. In an exemplary embodiment, middle channel 12 can extend along the entire length or partial length of the first absorbent core 10.

[0030] like Figure 1B As shown, the second absorbent core layer 20 is a prefabricated synthetic absorbent core composed of two carrier layers 24 and a nonwoven layer 26 disposed between the two carrier layers 24. In an exemplary embodiment, the carrier layer 24 is made of a spunbond material, and the nonwoven layer 26 is a high loft polyester nonwoven material embedded with a low-speed, high-permeability SAP. Figure 2A and Figure 2B As shown, the lateral ends of the second absorbent core layer 20 are folded over the second absorbent core layer 20, so that the second absorbent core layer 20 presents a "C-shape". This folding forms a central channel 22 in the middle of the absorbent article that runs through the entire length of the second core layer 20. The central channel 22 formed by the absorbent material helps to avoid run-offs, which is a typical problem of absorbent articles with full-length channels. In this regard,Figure 2A and Figure 2B The arrows in Figure 2B show the direction of liquid flow through the second absorbent core layer 20.

[0031] The first ADL layer 30 and the second ADL layer 50 may be made entirely of conventional fiber materials with little absorbency, but in some embodiments include water-absorbent polymer particles or other absorbent materials. The fiber materials may be hydrophilic, hydrophobic, or may be a combination of hydrophilic and hydrophobic fibers. The fiber materials may be derived from natural fibers, synthetic fibers, or a combination of both. Suitable ADLs are formed from cellulosic fibers and / or modified cellulosic fibers and / or synthetics or combinations thereof. Thus, suitable ADLs may contain cellulosic fibers, particularly woodpulp fluff. Modified cellulosic fibers may be used for fluid collection and distribution. Examples of modified cellulosic fibers are cellulosic fibers that have been chemically treated, particularly chemically stiffened cellulosic fibers. The basis weight of the cellulosic fibers and the modified cellulosic fibers may be from about 50 gsm to about 200 gsm.

[0032] Suitable ADL layers may further include synthetic fibers. Hydrophilic synthetic fibers may be obtained by chemical modification of hydrophobic fibers, for example, by surfactant treatment of hydrophobic fibers. The surface of the hydrophobic fibers may be made hydrophilic by treatment with non-ionic or ionic surfactants, for example, by spraying the fibers with a surfactant or by immersing the fibers in a surfactant.

[0033] In some embodiments, the ADL layers 30, 50 include a fiber material and water-absorbent polymer particles distributed therein to act as an absorbent layer. Based on the total weight of the ADL, the ADL may include from about 80% to about 100% (by weight) of the fiber material and from 0% to about 20% (by weight) or from about 5% to about 15% or about 10% (by weight) of the water-absorbent polymer particles.

[0034] Alternatively, a synthetic fiber bundle loosely distributed on top of the fluid absorption core can be used as the ADL. Suitable synthetic fibers include, for example, copolyester, polyamide, copolyamide, polylactic acid, polypropylene or polyethylene, viscose, or mixtures thereof. Bicomponent fibers can also be used. In an exemplary embodiment, the synthetic fiber component can consist of a single fiber type with a circular cross-section or a mixture of two fiber types with different cross-sectional shapes.

[0035] The basis weight of the ADL can be from about 20 gsm to about 200 gsm, depending on the concentration of the water-absorbent polymer particles. The length of the upper ADL can be from about 6 cm to about 25 cm. The width of the upper ADL can be from 4 cm to 12 cm. The length of the lower ADL can be from about 6 cm to about 60 cm. The width of the lower ADL can be from 6 cm to 15 cm.

[0036] In an exemplary embodiment, the core wrapper 40 can contribute to the containment and integrity of each absorbent core component. The core wrapper 40 can be combined with one or both of the first core layer 10 and the second core layer 20. The combination of the core wrapper 40 with the absorbent cores 10, 20 can be carried out in any manner known to those skilled in the art, such as, but not limited to: adhesives (such as hot melt adhesives in the form of sprays), melt-blown, multi-lines, slots, etc. The core wrapper 40 can consist of several individual material sheets (for example, an upper core wrapper and a lower core wrapper), which can be used to partially or completely surround the absorbent cores 10 and 20, and can be sealed together using sealing means (such as an ultrasonic bonder or other thermochemical bonding means) or using an adhesive. Alternatively, as Figure 1A shown, the core wrapper 40 can consist of only a single piece of material wrapped around the cores 10, 20. The core wrapper 40 can include, but is not limited to: natural and synthetic fibers, such as polyester, polypropylene, acetate, nylon, polymer materials, cellulose materials (such as wood pulp, cotton, rayon, viscose, (e.g., Lenzing from Austria), or mixtures of these or other cellulose fibers), and combinations thereof. Natural fibers may include wool, cotton, flax, hemp, and wood pulp. The material forming the core sheath 40 may be selected from meltblown-spunbond-meltblown fabric, spunbond fabric, meltblown fabric, coform fabric, carded web, bonded-carded web, bicomponent spunbond fabric, spunlace, tissue, and combinations thereof. Additionally, the core sheath 40 may be made of spunbond-meltblown-spunbond (SMS) material, e.g., 9 gsm spunbond-meltblown-spunbond material.

[0037] The hydrophilicity of the core sheath 40 may be lower than that of the absorbent cores 10, 20, but have sufficient porosity to allow body fluids to pass through the core sheath 40 to reach the absorbent cores 10, 20. The core sheath 40 may have sufficient structural integrity to withstand its own wetting and the wetting of the absorbent cores 10, 20. To support this functional characteristic of the core sheath 40, a wet strength agent may be applied to the core sheath 40. Non-limiting examples of the wet strength agent may be Kymene 6500 (557LK) or an equivalent obtainable from Ashland, Inc. in Kentucky, USA. Similarly, surfactants may be included in the core sheath 40 to promote hydrophilicity.

[0038] The combination of the first absorbent core layer 10 and the second absorbent core layer 20 provides a solution to the problems associated with using a traditional core or a synthetic core alone, especially when the second absorbent core layer 20 (which is a prefabricated synthetic core) is folded on two edges to form a central channel as described above. By carefully selecting SAPs with different properties, e.g., selecting a slow and highly permeable SAP for the upper prefabricated core 20 and a fast SAP for the lower traditional core 10, fluid intake through the central channel can be quickly accepted even when the diaper is tilted, without any risk of liquid seepage. This is because the lower layer of the channel 22 has absorbent material that can slow down the seepage rate, while also allowing the liquid to penetrate deeper into the traditional core 10 with high-speed SAP below.

[0039] In addition, by carefully selecting the ADLs used in this new core structure, liquid intake can be optimized. In this way, ADLs with different densities can be used to create an effective density gradient that helps the liquid move faster while making it difficult for the liquid to return. In this regard, in an exemplary embodiment, the first ADL layer 30 disposed above the preformed core 20 can be a full-length ADL, while the second ADL layer 50 disposed above the core wrap layer 40 can be a shortened-length ADL (e.g., an ADL patch). Without being bound by theory, this structure takes advantage of the fact that liquids generally flow from open structures to denser structures, thus forming an analogy to a check valve. Using a shortened-length ADL layer at the top of the core wrap layer 40 is advantageous as it can reduce potential leakage at the top and bottom (i.e., above and below) of the absorbent core edges and reduce additional costs by positioning the shortened-length ADL layer exactly in the target area. In an exemplary embodiment, the second ADL layer 50 may not have the same basis weight as the first ADL layer 30.

[0040] The absorbent system 1 can be used, for example, in diapers, training pants, youth pants, briefs, sanitary pads, bladder control pads, etc. In use, the absorbent system of an exemplary embodiment of the present invention is placed on the top surface (or "upper surface") of a backsheet (e.g., Figure 1A the backsheet 70 shown). The backsheet is typically a liquid-impermeable material, but can also be a water-vapor-permeable (breathable) material. The backsheet is used on the product surface of the absorbent product that is away from the user's body. The backsheet can be made of any known or otherwise effective backsheet material, provided that the backsheet can prevent the absorption and outward leakage of exudates contained in the protective underwear. Suitable flexible materials for use as the backsheet include, but are not limited to: woven materials and non-woven materials, laminated tissue, polymer films (e.g., thermoplastic films of polyethylene and / or polypropylene), microporous films, composite materials (e.g., non-woven materials coated with a film), or combinations thereof, as are well known in the field of manufacturing absorbent products (e.g., sanitary pads, pantiliners, incontinence pads, etc.). The water vapor transmission rate of the breathable backsheet can be, for example, 0 to 9000 g / m per 24 hours 2 .

[0041] An absorbent system is typically attached to a substrate using an adhesive. Suitable adhesives are known in the art and include hot melt adhesives, emulsion polymer adhesives, and the like.

[0042] A topsheet or cover (such as Figure 1A topsheet 60 as shown) is placed on top of the absorbent system and attached to the absorbent system and the substrate by an adhesive, ultrasonic bonding, or a combination thereof to form a chassis. Suitable topsheets are compliant, soft and comfortable, and non-irritating to the wearer's body. Suitable topsheet materials include materials that are permeable to liquids, which face and contact the wearer's body, thereby allowing body excretions to quickly penetrate the topsheet without allowing the fluid to flow back to the wearer's skin through the topsheet. Suitable topsheets can be made of a variety of materials, for example, nonwoven materials and nonwoven materials; apertured film materials, including apertured formed thermoplastic films, apertured plastic films, and fiber-entangled apertured films; hydro-formed thermoplastic films; porous foams; reticulated foams; reticulated thermoplastic films; thermoplastic scrims; or a combination thereof, as is well known in the art of manufacturing absorbent products such as sanitary napkins, pantiliners, incontinence pads, protective underwear, and the like.

[0043] Elastic side panels can be attached to the base described above to form a diaper or an adult protective undergarment. Any elastic side panels known in the field of absorbent articles are useful. Suitable elastic side panels include laminates of elastic films and nonwovens, laminates of elastic strands and nonwovens, etc. The elastic side panels can be attached to the base by adhesives, ultrasonic bonding, or a combination thereof. The length, width, and shape of the side panels can be designed to manufacture products of different sizes. The product with side panels may have a more underwear-like appearance. A portion of each side panel is not attached to form a leg opening. These side panels can be attached to the base at various angles to form a more clothing-like fit.

[0044] As is known in the art, hook&Loop can be used on the articles according to the exemplary embodiments of the present invention. The nonwoven material can act as the Loop.

[0045] In an exemplary embodiment, the above-mentioned hook fasteners can be composed of separate hook elements or can be integral with the side panels. In this regard, the hook elements can be bonded to the side panels by adhesives, ultrasonic waves, thermal bonding, etc. Alternatively, the hook elements can be tightly joined to the material forming the side panels. The hook elements can be arranged on the side panels in the form of longitudinally extending strips that are laterally spaced apart from each other. Alternatively, these hook elements can be arranged in a geometric shape or a pattern of lines. Preferably, the hook elements are arranged on a non-elastic material to improve the ease of processing and the shear strength of the seams.

[0046] Table 1 below provides the materials, material names, material compositions, basis weight ranges, and preferred basis weights of the components of an absorbent article according to an exemplary embodiment of the present invention. The materials and material properties used in the exemplary embodiments of the present invention are not limited to those provided in Table 1. For example, nonwoven materials made of fibers other than those listed in Table 1 can be used, such as bicomponent polypropylene-polyethylene, polyester, and polybutylene terephthalate, etc.

[0047] Table 1

[0048]

[0049]

[0050] Since the introduction of the first disposable diaper, three characteristics have been of critical importance. These three characteristics are the liquid retention capacity, the speed of acquisition, and the rewet volume (collectively referred to as the "Tripod Properties").

[0051] The liquid retention capacity is used to measure the amount of urine that a disposable diaper can hold under a specific pressure. For a disposable diaper that uses a substantially flat core along its width and length, the liquid retention capacity can be directly measured by applying different pressures on the top of the wet core (e.g., using a plate that replicates the shape of the core and a pneumatic piston to increase the pressure). For cases where the absorbent core is not flat, such as when testing a disposable diaper that uses a 3D absorbent core, a centrifuge can be used to indirectly correlate its liquid retention capacity. Assuming that the disposable diaper does not exhibit initial leakage related to slow fluid intake relative to the speed of insult, the liquid retention capacity is closely related to the duration that a disposable diaper can typically be used before leakage occurs (e.g., before reaching its designed capacity). Ideally, the liquid retention capacity is relatively high to allow the disposable diaper to be used for a longer time, thus requiring a smaller number of disposable diapers per day. Appendix A provides a method for measuring the liquid retention capacity using pressure (i.e., "Free Swell Capacity") and another method using a centrifuge (i.e., "Retention Capacity").

[0052] The speed of acquisition attempts to measure the time required for the core to absorb urine. Once excrement is added to a cylinder in direct contact with the absorbent core, a timer is started, and once there is no visible liquid in the cylinder, the timer is stopped. There are many ways to measure this, such as measuring the time required for a certain amount of excrement to be completely absorbed using cylinders of different diameters; or, using funnels with different angles and different diameter orifices, etc. The acquisition time is closely related to potential initial leakage. If the speed is too slow, a pool of urine liquid that has not yet been absorbed by the core may form. Under certain special conditions, this pool of liquid may cause initial leakage, i.e., leakage that occurs before the disposable diaper reaches its designed liquid retention capacity, for example, when the disposable diaper is at a certain angle and the disposable diaper has only absorbed a small portion of its designed liquid retention capacity. Many sealing features are added to disposable diapers, such as leg gathers, leg cuffs, waist elastics, etc. In most cases, these features can reduce some leakage, but when the speed of acquisition is too slow, they cannot prevent all leakage in most cases. A preferred method for measuring the speed of acquisition is provided in Appendix B.

[0053] Rewet attempts to measure the comfort of the user. If a baby's skin is wet while wearing a diaper, they will quickly feel cold because the room temperature is usually lower than body temperature. This is amplified by using modern breathable diapers, which allow the liquid to evaporate and create a colder feeling. The wetter the skin, the more uncomfortable the user, often causing the baby to cry or the adult to switch to another brand. Rewet measures the amount of liquid that can return to the surface using filter paper under pressure. It attempts to measure the comfort of the skin. The drier the skin, the more comfortable. To measure rewet, first, excrement is added to the core and then allowed to absorb for a specific time. After that, filter paper is placed on top of the core under pressure to measure the amount of liquid returning to the surface. Appendix B also includes a preferred method for measuring rewetability.

[0054] Appendix C provides a method for measuring incline run off.

[0055] The above tests were conducted on a diaper ("C-shaped folded unique core") according to an exemplary embodiment of the present invention and other diaper structures (including diapers with an absorbent system having only a standard core ("SAP sheet") and commercially available diapers, which include "Coterie The diaper", "Pampers Swaddlers", and "Huggies Little Snuggler"). Additional tests were also conducted, including strikethrough (the test provided in Appendix B). The results of these tests are shown in Table 2.

[0056] Table 2

[0057]

[0058] As shown in Table 2, the absorbent system of the present invention including a C-shaped folded core achieves a combination of tripod characteristics, providing a well-balanced high-performance product with a high liquid retention capacity while maintaining a fast liquid collection speed and a low rewet amount (especially under long-term use, with emphasis on the second and third rewet). In addition, due to the wicking characteristics that can quickly transport the liquid to the bottom, for the traditional pulp-plus-SAP core, the rewet characteristics are better demonstrated in the QuickRewet test (which uses a funnel instead of a cylinder to manage excrement).

[0059] The absorbent system of the present utility model achieves a very fast liquid collection speed, even when compared to the market leader in designs including channel cores ("Pampers"), or to Coterie The Diaper (Coterie The Diaper has the highest basis weight ADL (110 gsm) among all diapers designed in combination with very high-speed Sumitomo "grape-shaped" SAP and a high pulp / SAP ratio of 43 / 57).

[0060] In traditional cores, such as those made of a mixture of SAP and fluff, most of the SAP is located near the top of the core (close to the user's skin). Therefore, the diaper performs well in terms of rewet amount and is dry for the skin, but is very poor in terms of liquid collection time, and early leakage may occur.

[0061] Similarly, diapers made of SAP sheets or "absorbent paper" (defined as absorbent cores without cellulose (also known as "pulp-less")) also face similar challenges in achieving a competitive liquid collection speed. All tested SAP sheet pulp-less cores result in a slower liquid collection speed (e.g., DSF SAP sheets), or result in a competitive speed when longitudinal channels are introduced (e.g., "Coterie The Pant"), but the performance in the 30-degree angle test is poor due to the seepage of physiological saline from the front end of the core.

[0062] The absorbent system design of the present utility model results in a faster liquid collection time. Due to the high loading of SAP, the high SAP / pulp ratio, and the placement of the highest concentration of SAP closest to the user's skin, the result is counterintuitive.

[0063] Surprisingly, especially for diapers with such a high SAP load close to the baby's skin, the prefabricated core with channels results in surprisingly low slip and rewet amounts and the fastest liquid collection time. This unexpected result becomes clear after comparison with other diapers made of prefabricated cores made of SAP (compared to DSG). In addition, the diaper was also tested in the HUT, which confirmed and verified the expectation of extremely low leakage amounts (when compared to the market).

[0064] In summary, as shown in Table 2, the absorbent system of the present utility model provides diapers with the fastest performance in terms of liquid collection time, one of the driest diapers in terms of rewet amount, and one of the diapers with the highest SAP load near the surface.

[0065] In addition, the channel core of the absorbent system of the present utility model not only provides a very fast liquid collection time, but also avoids the need for size change in the absorbent core, thereby avoiding the need for core registration and the additional downtime and lower efficiency associated with the use of interrupted channels.

[0066] The embodiments of the present utility model have been shown and described in detail above. For those skilled in the art, various modifications and improvements can be easily made to these embodiments of the present utility model. Therefore, the exemplary embodiments of the present utility model as described above are intended to be illustrative rather than restrictive. The spirit and scope of the present utility model should be broadly interpreted.

[0067] Appendix A - Saturated Liquid Absorption (Free swell) and Liquid Retention of Infant Absorbent Hygiene Products

[0068] (Retention)

[0069] Purpose

[0070] This method describes the determination process of an infant absorbent hygiene product for absorbing and retaining 0.9% saline solution.

[0071] Principle

[0072] Infant absorbent hygiene products have various absorbent materials and absorbent core designs, which contain different amounts of fibers and absorbent polymers. The amounts of these materials are set to provide a specific total capacity and liquid retention capacity during consumer use. Generally, the goal of these two values is the result of specifically designing absorbent hygiene products for the following intended uses: for example, infants of a specific age or body size, use during the day or at night, premium and value absorbent hygiene products. This test can make a direct comparison of these types of products and help understand consumers' usage expectations.

[0073] In this test, the absorbent hygiene product completely absorbs the saline solution and then releases the free fluid by gravity to provide the capacity of the free well. The interstitial fluid is removed by centrifugation to provide the retention capacity.

[0074] Reagents

[0075] 1. 0.9% w / w sodium chloride (NaCl) solution, made from solid NaCl and distilled water or deionized water.

[0076] Equipment and Materials

[0077] 1. Digital timer;

[0078] 2. Scissors;

[0079] 3. Electronic scale: with a maximum weighing capacity of 1000 g or higher and a reading accuracy of up to 0.1 g;

[0080] 4. Centrifugal dryer: 3200 revolutions per minute, with a 23-inch ID drum (Panda PANSP23B or equivalent);

[0081] 5. Submersion tray that can hold 20 L of 0.9% saline solution, sized to hold 6 absorbent hygiene products;

[0082] 6. Fixed bracket above the sink for holding absorbent hygiene products during gravity drainage;

[0083] 7. Clips;

[0084] 8. Large bowl.

[0085] Conditions

[0086] The absorbent hygiene product should be removed from the packaging and allowed to equilibrate for 15 minutes under ambient conditions (this allows the absorbent hygiene product to relax from the compressed packaging).

[0087] The laboratory environment and test conditions are preferably 23 ± 1 °C and a relative humidity of 50 ± 2%. If these conditions cannot be maintained, the actual test conditions must be recorded and included in the report.

[0088] General operation

[0089] Cut the elastic material that holds the absorbent hygiene product in a cup shape so that the absorbent hygiene product can lie flat. Immerse the absorbent product in 0.9% saline solution for a specific period of time, then remove and drain. This provides the absorption capacity. Then, centrifuge the product to determine the retention capacity.

[0090] Steps

[0091] 1. Weigh all the diapers in a bag (or bags) of absorbent hygiene products being tested. Calculate the average diaper weight for all absorbent hygiene product samples. Mark identification text and numbers on each absorbent hygiene product. Select six (6) absorbent hygiene products close to the average weight; record the ID and weight of each product as W DN , where N is the sample number from 1 - 6.

[0092] [Note: Regarding the testing of diapers, there are three schools of thought. One approach is to randomly select 3 - 5 products as they represent the consumer's preference. The second method is to select 3 - 5 products at the production mean as this is what the converter is attempting to manufacture and represents the average performance. The third method is to select 3 products from the mean and 1 product each from the extremes to further characterize the given product.]

[0093] 2. Take the first absorbent hygiene product and carefully cut the outer leg gathers on both sides of the product at several places, taking care to cut through the elastic material but not into the absorbent core.

[0094] 3. Next, cut the inner leg gathers (cuffs) on each side at several places, taking care to cut through the elastic material but not into the absorbent core. All the cutting operations with scissors will keep the absorbent hygiene product flat during the immersion process.

[0095] 4. Repeat steps 2 and 3 for the other 5 samples.

[0096] 5. Fill the immersion tray with 20 L of 0.9% saline solution.

[0097] 6. Reset the timer to zero and stack the absorbent hygiene products in numerical order near the immersion tray.

[0098] 7. Hold the two ends of the first sample so that it is open and flat, with the porous surface facing downwards towards the saline solution. Place the sample into the immersion tray and then, start the timer. Gently press the sample into the saline solution so that it floats but is submerged.

[0099] 8. When the timer reaches 10 seconds, immerse the second sample in the same way as in step 7. Repeat this operation every 10 seconds until all samples are immersed, ensuring that they do not overlap.

[0100] 9. When the timer reaches 10:00 minutes, remove the first absorbent hygiene product and hang it on the crossbar of the fixed bracket above the sink using a clip. Ensure that the porous surface faces forward. Take care not to inadvertently squeeze the liquid in the absorbent hygiene product.

[0101] 10. Repeat step 9 for the other 5 absorbent hygiene products every 10 seconds.

[0102] 11. When all the samples are hung, quickly place the lid longitudinally along the width of the tray on the immersion tray. This is where the samples are placed for transportation and subsequent operations.

[0103] 12. When the timer reaches 12:00 minutes, remove the first absorbent hygiene product, gently fold it and place it on the immersion tray lid.

[0104] 13. For the remaining 5 absorbent hygiene products, repeat step 12 every 10 seconds.

[0105] 14. Place the large bowl on the scale and press the zero (or tare) button so that 0.00 g is displayed on the display screen.

[0106] 15. Weigh each absorbent hygiene product and record the weight as W FSN , where N is the number of the absorbent hygiene product from 1 to 6 (FS stands for "free swell"). Ensure that the scale is re-zeroed / tared between each weighing.

[0107] 16. Check if the centrifuge is plugged in and if there is a container under the drain pipe to capture the fluid drained from the absorbent hygiene product.

[0108] 17. Place sample 1 in the centrifuge with the porous top layer facing outwards towards the drum and pressed against the curvature of the drum.

[0109] [Note: During the hanging / draining operations in steps 9 - 12, the absorbent core of some absorbent hygiene products may sag. If this occurs, gently press the absorbent hygiene product to evenly distribute the absorbent core within the absorbent hygiene product. This will improve the balance of the absorbent hygiene product in the centrifuge and ensure even dehydration.]

[0110] 18. Place sample 2 in the centrifuge in the same way as sample 1, but on the other side of the drum. This will balance the load during centrifugation.

[0111] 19. Close the centrifuge lid. Turn the handle to the right (clockwise) to turn on the centrifuge and start the timer simultaneously. Let the centrifuge run for 1 minute and 6 seconds (these 6 seconds account for the time required for the centrifuge to reach 3200 rpm).

[0112] [Note: If the centrifuge starts to shake during startup, it may be necessary to hold it.]

[0113] 20. Turn the handle to the left (counterclockwise) to stop the centrifuge. Let it come to a gradual stop on its own.

[0114] 21. Ensure that the bowl is on the scale and the scale is zeroed / tared so that the screen reads 0.00 g.

[0115] 22. Remove absorbent hygiene product 1 and weigh it, record the weight as W RN, where N is the number of the absorbent hygiene product (R represents "Retention"). Reset the weighing to zero and repeat this process for absorbent hygiene product 2.

[0116] 23. Repeat steps 16 - 22 for the remaining absorbent hygiene products in pairs.

[0117] 24. If further tests are to be carried out, refill the immersion tray with 20 L of normal saline; otherwise, empty and rinse the immersion tray.

[0118] 25. To prevent corrosion of the centrifuge, at the end of all tests, rinse the centrifuge drum with 1 - 2 L of tap water, then run the centrifuge to drain the water through the drain pipe. Empty the centrifuge drainage container in the sink.

[0119] Calculation

[0120] Free swell capacity (FSC) = W FSN - W DN

[0121] Retention capacity (CRC) = W RN - W DN

[0122] Data table

[0123]

[0124] Appendix B - Acquisition and rewet of baby absorbent hygiene products

[0125] Purpose

[0126] This method describes the determination process of the acquisition time and rewet value when 0.9% normal saline is applied to a baby absorbent hygiene product (AHP) placed in a flat state.

[0127] Principle

[0128] Generally, the acquisition and rewet tests are carried out with the absorbent hygiene product lying flat on the surface, which helps for quick testing. The initial acquisition and rewet tests were designed to meet quality assurance requirements and have now evolved into recognized performance tests in the hygiene industry.

[0129] In the flat state, the fluid is easily distributed in the X - Y plane, and the main force involved is the fluid head pressure. Other forces are the capillary forces in the absorbent structure, which act along the entire length of the product when it is lying flat.

[0130] The use of load in this test is not generally accepted, and the magnitude of the load force (psi) varies across the industry. The idea is to simulate the pressure exerted by the wearer on the product and how this pressure affects the liquid collection and rewetting performance. This test uses a load during the liquid application process.

[0131] This test provides an assessment of the fluid intake and management of the absorbent system (topsheet, liquid collection layer, and absorbent core).

[0132] Reagent

[0133] 1. A 0.9% w / w sodium chloride (NaCl) solution made from solid NaCl and distilled or deionized water.

[0134] Equipment and Materials

[0135] 1. Five digital timers;

[0136] 2. Five TD graduated cylinders, 250 ml capacity (Fisher 03-007-42 or equivalent);

[0137] 3. Filter paper: 9 cm, No. 1, qualitative (United Scientific FPR009 or equivalent);

[0138] 4. Cylindrical weights: 9 cm outer diameter, 2.3 kg;

[0139] 5. Five dosing cylinders (the inner tube of the dosing cylinder is made of plexiglass and the outer ring is made of stainless steel);

[0140] 6. Plexiglass block (10 cm long, 10 cm wide, 5.5 mm high, 64.9 g);

[0141] 7. Electronic scale: maximum weighing capacity of 100 g or higher, readable to 0.01 grams;

[0142] 8. Five cork mats with associated clips / pins for fixing the stretching plane of the absorbent hygiene product;

[0143] 9. Five diaper samples;

[0144] 10. Plastic cups capable of holding at least 150 ml of 0.9% saline solution.

[0145] Conditions

[0146] The absorbent hygiene product should be removed from the package and allowed to equilibrate for 15 minutes under ambient conditions (this allows the absorbent hygiene product to relax from the compressed package).

[0147] The laboratory environment and test conditions are preferably 23 ± 1 °C and the relative humidity is 50 ± 2%. If these conditions cannot be maintained, the actual test conditions must be recorded and included in the report.

[0148] General operation

[0149] Lay the absorbent hygiene product flat and fix it on a support. Place a fluid delivery cylinder that exerts substantially no pressure on the absorbent hygiene product on the surface layer of the absorbent hygiene product, and add 0.9% physiological saline (a substitute for urine) to the product in an amount consistent with the product size. The inhalation (or intake) time (collection time) is recorded as the time required for all the fluid to be absorbed into the absorbent hygiene product. Ten minutes after starting the addition of the fluid, a stack of weighted filter papers is used to determine the free moisture (back leakage) in the area near the fluid addition. This process is repeated three times to produce the measurement set required for a single absorbent hygiene product. Five absorbent hygiene products are tested to provide the performance indicators for a given group of diapers.

[0150] [Note: There is no fixed amount of physiological saline dosage in the diaper industry. Generally, quality assurance laboratory tests are conducted with two determinations. However, product development laboratories may use 3, 4, or 5 fluid additions to apply pressure to the product to meet development needs.]

[0151] Steps

[0152] 1. Weigh all the diapers in a bag (or multiple bags) of absorbent hygiene products being tested. Calculate the average diaper weight of all the absorbent hygiene product samples. Mark identification text / numbers on each absorbent hygiene product.

[0153] [Note: Regarding diaper testing, there are three schools of thought. One method is to randomly select 3 - 5 products because they represent the consumer's preference. The second method is to select 3 - 5 products at the production mean because this is what the converter is trying to manufacture and represents the average performance. The third method is to select 3 products from the mean and 1 product each from the extreme values to further characterize a given product.]

[0154] 2. Select 5 absorbent hygiene products close to the average absorbent hygiene product weight measured in step 1. Record the weight of each absorbent hygiene product as W AX (where "x" is the number corresponding to the product number (W A1 、W A2 etc.).

[0155] 3. Place each selected sample flat on a cork mat. Ensure that the sample core is completely horizontal and fully stretched to reduce any wrinkles that may be present on the surface. Fix it in place using pins or clips. The diaper should be positioned such that the front part of the diaper is at the upper part of the mat, while the rear part of the diaper is at the lower part of the mat.

[0156] 4. For each absorbent hygiene product, measure the length of the absorbent core. Using a marker pen, mark a point at 1 / 3 of the distance between the front and the back of the absorbent hygiene product core.

[0157] 5. Using a graduated cylinder, add the required amount of physiological saline (see Annex B) to each plastic cup.

[0158] 6. For each absorbent hygiene product, select ten (10) filter papers. Stack the papers and staple them together (the staples near the edge). Weigh the stack of dry filter papers and record the weight as W N (where N is a number from 1 to the number of absorbent hygiene products being tested).

[0159] 7. Place the dosing cylinder at the center next to the marked point on each absorbent hygiene product. Lift the inner leg gathers with your finger or a pen / rod to prevent accidental leakage of physiological saline.

[0160] 8. Using a graduated cylinder or a plastic cup, quickly (less than 3 seconds) pour the physiological saline into the dosing cylinder, ensuring that it does not splash. Once you start pouring the physiological saline into the graduated cylinder, start the timer.

[0161] If the dosing cylinder tilts due to uneven expansion, it may be necessary to support the dosing cylinder during filling.

[0162] 9. When all the fluid has been absorbed by the absorbent hygiene product, note the time and record it as AQ N (where N is a number from 1 to the number of absorbent hygiene products being tested). Remove the dosing cylinder and prepare to fill the next absorbent hygiene product (it is recommended to leave 15 - 25 seconds between each filling of five absorbent hygiene products).

[0163] 10. Reset and restart the timer. When the timer reaches 10 minutes, stop the timer, place ten filter papers at the target position. Gently place the plexiglass sheet on the filter papers, and then place the 2.3 kg cylindrical weight on the plexiglass, taking care not to apply any additional pressure. Reset and start the timer.

[0164] 11. After 2 minutes, remove the weight, the plexiglass block, and the stack of filter papers, weigh the filter papers, and record the weight as W W1 .

[0165] 12. Repeat steps 7 - 11 for the second and third liquid additions to each absorbent hygiene product, recording AQ and the filter paper stack weight W, with subscripts for the given number of liquid additions.

[0166] [Note: Use one filter paper stack for all liquid additions required for the test.]

[0167] 13. Take a photograph of the absorbent hygiene product to record the fluid distribution.

[0168] 14. When all tests are complete, carefully remove the acquisition / distribution layer (ADL) and mark it with identification information for archiving.

[0169] Calculation

[0170] The method calculates the total rewet, not the sequential rewet. Therefore, all filter paper weights are related to the initial dry weight.

[0171] The rewet is calculated as follows: W WN –W1 = RW N

[0172] Data table

[0173]

[0174] Appendix B - Normal Saline Dosage Guidelines

[0175] There is no industry standardization for the normal saline dosage required for the rewet and acquisition tests. The following table gives the dosage volumes for size - based infant absorbent hygiene products.

[0176]

[0177] The following table gives the expected average values of infant exudate based on the age and body size of infants and toddlers:

[0178]

[0179] *Source: Absorbent Products Design Symposium 2016, Marketing Technology Service

[0180] Appendix C - Sliding Rewet at 30°

[0181] · Prepare a 0.9% sodium chloride solution (using deionized water or distilled water or equivalent water and ACS - grade or better NaCl), and use a coloring agent to visualize the fluid track.

[0182] · Lay the core (along with the core cladding and ADL (if any)) flat at an inclination of 30°. Point the front end of the core towards the bottom so that the fluid flows downward towards the front.

[0183] · Mark the excrement position at 195 mm from the front end of the gasket towards the back (MD) and at the middle CD.

[0184] · Adjust the excrement flow rate to 7 ml / s (total excrement volume of 85 ml in 12 seconds).

[0185] · Adjust the open end of the excrement hose, beaker or funnel so that it is placed 5 mm from the sample surface, and place it at a 90-degree angle to the core so that the excrement flows vertically at 90 degrees towards the excrement position.

[0186] · Record the number of seconds when the first slippage is observed.

[0187] · Weigh the total slippage fluid or weigh the total weight gain of the core.

Claims

1. An absorbent system, characterized in that, It includes: A first absorbent core layer, the first absorbent core layer including cellulose and a superabsorbent material; A second absorbent core layer, which is disposed above the first absorbent core layer, the second absorbent core layer including a synthetic material and a superabsorbent material, the second absorbent core layer having a folded end such that the second absorbent core layer has a C shape; A first liquid collection and distribution layer, which is disposed above the second absorbent core layer; A core wrapper layer, the core wrapper layer being disposed around the first absorbent core layer, the second absorbent core layer and the first liquid collection and distribution layer; And A second liquid collection and distribution layer, which is disposed above the core wrapper layer.

2. The absorbent system according to claim 1, wherein The second absorbent core layer includes a nonwoven layer disposed between two carrier layers.

3. The absorbent system according to claim 2, wherein The carrier layer includes a spunbond material.

4. The absorbent system according to claim 1, wherein The second absorbent core layer includes a channel formed between the ends.

5. The absorbent system according to claim 1, characterized in that, The first absorbent core layer includes a channel.

6. The absorbent system according to claim 5, wherein The first absorbent core layer includes a first part and a second part, and the channel is formed by a space between the first part and the second part.

7. The absorbent system according to claim 5, wherein The channel is formed by a part of the second absorbent core layer having a reduced amount of superabsorbent material.

8. The absorbent system according to claim 5, characterized in that, The channel is formed by a part of the second absorbent core layer having a reduced thickness.

9. The absorbent system according to claim 1, wherein The first liquid collection and distribution layer is larger than the second liquid collection and distribution layer.

10. The absorbent system according to claim 1, characterized in that, The extension length of the second liquid collection and distribution layer is less than the full length of the absorbent system.

11. An absorbent article, which includes the absorbent system according to claim 1.

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