Absorbent article with high permeability SAP

Abstract

To provide an absorbent article that has good fluid management characteristics, is comfortable to use, and does not lose its integrity during use. [Solution] An absorbent article 20, such as a diaper, comprising a liquid-permeable top sheet 24, an upward capture and distribution systems 52, 54, an absorbent core 28 including a layer 60 of superabsorbent polymer particles disposed within core wraps 45, 46, and a liquid-impermeable back sheet 25. The superabsorbent polymer particles are preferably not mixed with cellulose fibers. The upward capture and distribution systems are substantially free of unbound crosslinked cellulose fibers. The superabsorbent polymer particles have a UPM value of at least 45 UPM units and preferably an EFFC greater than 23 g / g. The absorbent core optionally includes channel-forming regions. The absorbent article optionally includes a downward capture and distribution layer 56.

Description

[Technical Field]

[0001] This invention relates to absorbent articles for personal hygiene, such as infant diapers and adult incontinence products. [Background technology]

[0002] Disposable absorbent items, such as diapers, include an absorbent core positioned between a liquid-permeable top sheet facing the wearer and a liquid-impermeable back sheet facing the clothing. The absorbent core typically contains absorbent material disposed within a core wrap. Urine is captured by the absorbent item through the top sheet and absorbed by the absorbent material.

[0003] Superabsorbent polymers (SAPs) are commonly used as absorbent materials. Surface crosslinking is known to increase the permeability and swelling rate of SAPs, but different performance profiles of SAPs are also known to involve trade-offs between one property and the other. Specifically, one known trade-off is between permeability and capacity. Increasing the permeability of SAPs can improve locally accessible capacity at faster ejection, but this reduces capacity at slower ejection and higher loads, where capacity is a more important property than permeability.

[0004] Superabsorbent polymers (SAPs) typically take the form of particles mixed with cellulose fibers (the core is called a "fluff pulp" or "air felt" core). Absorbent cores that do not contain cellulose fibers ("air felt-free" cores) have also been proposed. SAPs can be encapsulated, for example, in separate pockets formed between two substrate layers (see, e.g., International Publication 95 / 11654, Tanzer et al.). It has also been proposed to immobilize SAP particles onto nonwoven substrates with a microfiber thermoplastic adhesive network (see, e.g., International Publication 2008 / 155699(A1), Hundorf et al.).

[0005] Most personal absorbent hygiene articles have a trapping layer directly beneath the top sheet. The trapping layer provides rapid capture of fluid from the top sheet. In some absorbent articles, a distribution layer is further present between the trapping layer and the absorbent core. The distribution layer distributes the fluid across the entire plane of the absorbent article to maximize the use of the absorbent material. The distribution layer may be in direct contact with the absorbent core. Distribution layers made of cross-linked cellulose fibers have been used in combination with air felt-free cores; see, for example, U.S. Patent Application Publication 2008 / 0312622 (Hundorf). While cross-linked cellulose fibers have a fast trapping rate, distribution layers made from these cross-linked cellulose fibers exhibit poor integrity during use because unbound cellulose fibers can form wet aggregates. Such distribution layers may be several times thicker than the dry absorbent core.

[0006] The overall sensory performance of absorbent materials should ideally be soft, thin, and flexible. Combinations of flexible nonwoven fabric layers have recently been proposed as capture and distribution systems for airfelt-free core articles (see, for example, U.S. Patent Application Publication 2021 / 0106471 (Yuan)). However, the relatively reduced volume and lower permeability of these nonwovens may result in slower capture times, potentially leading to increased product leakage during use. In particular, airfelt-free absorbent cores may not have sufficient absorption rates to adequately handle large volumes of liquid (since superabsorbent polymer materials typically absorb liquid more slowly than cellulose fibers, especially when the initial spurt of liquid wets the article).

[0007] To maintain leakage performance, it is possible to increase the total amount of SAP in the core, but this leads to higher material costs. More recently, in order to improve fluid capture characteristics, it has been proposed to dispose a downward capture and distribution layer between the absorbent core and the backsheet (see International Publication No. 2021 / 118904 (Grenier)). Such a downward capture and distribution layer can improve the capture time, but its performance may still be slower than that of a diaper having an upward capture and distribution system including cross-linked cellulose fibers as the distribution layer.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Summary of the Invention

Problems to be Solved by the Invention

[0009] Therefore, there is a need for an absorbent article that addresses the above problems, specifically, that has good fluid management characteristics, is comfortable to use, and does not lose its integrity during use.

Means for Solving the Problems

[0010] In a first embodiment, the present invention is for an absorbent article comprising a liquid-permeable top sheet, an absorbent core including a layer of superabsorbent polymer particles and a core wrap, an upward capture and distribution system comprising a layer disposed between the top sheet and the absorbent core, and a liquid-impermeable back sheet. The superabsorbent polymer particles are measured by the Urine Permeability Measurement (UPM) method described herein, with a density of at least 45.10 -7 (cm 3 It has a urinary permeability of (s) / g and preferably an effective volume greater than 23 g / g, the effective volume of which is measured as described herein. Preferably, the superabsorbent polymer particles are not mixed with cellulose fibers.

[0011] The upward capture and distribution system is defined by all layers between the top sheet and the absorbent core. The upward capture and distribution system comprises one, two, or more layers and is substantially free of unbound crosslinked cellulose fibers.

[0012] The present invention enables absorbent articles without cross-linked cellulose fibers in the upper acquisition-distribution system to have an acquisition rate comparable to that of absorbent articles having cross-linked cellulose fibers in the upper acquisition-distribution system (ADS). Surprisingly, absorbent articles with an air felt-free core have been found to particularly benefit from the use of a highly permeable SAP, even when this reduces the overall core capacity compared to a higher capacity SAP.

[0013] The SAP used in the present invention provides the correct balance between capacity and permeability, particularly with respect to an air felt-free core that includes an upward capture and distribution system substantially free of cross-linked cellulose fibers. The upward capture and distribution system may include a spunlace nonwoven fabric, which has been found to be particularly useful in replacing the cross-linked cellulose fibers.

[0014] In a further aspect of the present invention, the absorbent core may include one or more longitudinally extending channel-forming regions formed by joining the upper and lower sides of the core wrap together in a material-free region surrounded by the absorbent material. These channel-forming regions(s) form three-dimensional channels when wet.

[0015] Therefore, the absorbent article may optionally also include a downward capture and distribution layer disposed between the absorbent layer and the backsheet. The downward capture and distribution layer is preferably disposed between the absorbent core and the backsheet, but may also be disposed within the absorbent core inside the core wrap. [Brief explanation of the drawing]

[0016] This specification concludes with the "Claims," ​​which describe the present invention in detail and clearly state the claims. However, it is believed that the contents of this specification will be better understood by reading the following description together with the accompanying drawings. [Figure 1] This is a diagram illustrating an example of an absorbent material in the form of a diaper. [Figure 2] Figure 1 is a cross-sectional view of a diaper. [Figure 3A] This is a cross-sectional view of an alternative diaper with a downward trapping and distribution layer. [Figure 3B] This is a cross-sectional view of an alternative diaper with a downward trapping and distribution layer. [Figure 3C] This is a cross-sectional view of an alternative diaper with a downward trapping and distribution layer. [Figure 4] This is a top view of an exemplary absorbent core with the upper layer partially removed. [Figure 5] Figure 4 is a longitudinal cross-sectional view of the absorbent core. [Figure 6] Figure 4 is a cross-sectional view of the absorbent core. [Figure 7] This is a partial cross-sectional side view of a suitable permeability measurement system for conducting urine permeability measurement tests. [Figure 8]This is a cross-sectional side view of a piston / cylinder assembly used when performing a urine permeability measurement test. [Figure 9] Figure 7 is a top view of a piston head suitable for use in the piston / cylinder assembly shown. [Figure 10] Figure 8 is a cross-sectional side view of the piston / cylinder assembly positioned on the frit disk for the swelling phase. [Modes for carrying out the invention]

[0017] definition As used herein, “absorbent articles” refer to personal hygiene devices positioned in or near the wearer’s groin to absorb and contain bodily excrement and various types of bodily waste. Absorbent articles include tape-type and pull-up diapers (for infants, toddlers, and adults), absorbent inserts (intended to be inserted into an outer cover to form a diaper or pants), and feminine care absorbent articles such as sanitary napkins or panty liners. As used herein, the term “excrement” includes, but is not limited to, urine, blood, vaginal discharge, sweat, and feces. The absorbent articles of the present invention are typically disposable and preferably recyclable.

[0018] As used herein, “diaper” generally refers to an absorbent article worn by infants, toddlers, and adult incontinence persons around the lower torso, encircling the wearer’s waist and legs, and particularly adapted to receive and contain urine and fecal excrement. Diapers are typically proposed as tape-type diapers or pull-up diapers. Tape-type diapers have a fastening system (for example, as shown in Figure 1) and when the diaper is fitted to the wearer, the longitudinal edges of the front and rear waist regions are detachably attached to each other to form waist and leg openings. In contrast, in pull-up diapers, the longitudinal edges of the waist regions are attached to each other to form pre-formed waist and leg openings. Pull-up diapers are positioned on the wearer by inserting the wearer’s legs into the leg openings and sliding the pull-up diaper to a position around the wearer’s lower torso. The pants may be pre-formed by any preferred method, including, but not limited to, joining together portions of the absorbent article using retightenable and / or non-retightenable fasteners (e.g., sutures, welds, adhesives, tacks, etc.). The pants may be pre-formed at any position along the outer circumference of the article (e.g., side fastening, front waist fastening).

[0019] As used herein, the terms “nonwoven fabric,” “nonwoven web,” and “nonwoven layer” are used interchangeably. Nonwoven fabric is broadly defined as a primarily planar artificial fiber assembly that is given a level of structural integrity designed by physical and / or chemical means other than weaving, knitting, or papermaking. Fibers may be of natural or artificial origin, such as cotton or bamboo fiber. Synthetic fibers may be selected from the group consisting of polyolefins (such as polyethylene, polypropylene, or combinations and mixtures thereof), polyethylene terephthalate (PET), co-PET, polylactic acid (PLA), polyhydroxy alkanoid (PHA), or mixtures or combinations thereof. Fibers may be staple fibers (e.g., carded nonwoven webs / layers) or continuous fibers (e.g., spunbond or meltblown nonwoven webs / layers).

[0020] Nonwoven webs / layers can be formed by many processes such as meltblowing, spunlay, solvent spinning, electrospinning, and carding, and the fibers can be solidified by, for example, water entanglement (in spunlace nonwoven webs / layers), air-through bonding (using hot air blown through the fiber layer in the thickness direction), needle punching, localized compression and / or application of thermal or ultrasonic energy to produce one or more bonding patterns and bond indentations, or a combination thereof. The fibers can also be solidified by the use of binders, either alternatively or additionally. Binders can be supplied in the form of binder fibers (which are subsequently melted) or in liquid form, such as styrene-butadiene binders. Liquid binders are supplied to the fibers (e.g., by spraying, printing, or foam coating) and subsequently cured and solidified. The basis weight of nonwovens is usually expressed in grams per square meter (g / m²). 2 It is represented as follows:

[0021] The term "spunlace" refers to a nonwoven fabric obtained by multiple water jets under pressure passing through a needle-like, moving fleece or cloth, causing the fibers to bind and entangle with each other, interweaving the fibers together. These spunlaces are defined in essence by the fact that their compaction results from hydrostatic confluence. As used herein, "spunlace" also refers to a nonwoven fabric formed from two or more webs (layers) that are combined with each other by hydrostatic confluence. The two webs may undergo a bonding process, such as thermal and / or pressure bonding, by imparting a bonding pattern using, for example, patterned calender rolls and anvil rolls, before being combined into a single nonwoven fabric by hydrostatic confluence. However, these two webs are combined with each other solely by hydrostatic confluence.

[0022] "Single-component" refers to a fiber formed from a single polymer component or a single formulation of polymer components, and is distinguished from two-component or multi-component fibers.

[0023] "Two-component" refers to a fiber having a cross-section containing two separate polymer components, two separate formulations of polymer components, or one separate polymer component and one formulation of a separate polymer component. "Two-component fiber" is encompassed within the term "multi-component fiber." A two-component fiber may have an overall cross-section divided into sub-sub

[0024] Examples of "multi-component fibers" include, but are not limited to, "two-component fibers." Multi-component fibers may have an overall cross-section divided into small parts of components of any shape or arrangement, including, for example, concentric core and sheath parts, eccentric core and sheath parts, parallel parts, island-in-the-sea parts, segmented pie parts, etc.

[0025] Nonwoven fabrics can be formed from various fibrous materials (PP, PE, PET, coPET, two-component materials, and mixtures thereof), and in some cases, the fibers or nonwoven fabrics can be processed to improve specific fluid handling properties such as fluid permeability or fluid barrier properties.

[0026] "dtex" as used herein refers to the unit used to indicate the fineness of a filament / fiber. This unit represents the mass of the filament / fiber in grams per 10,000 meters of length.

[0027] The term "hydrophilic" describes the surface of a substrate that can be moistened by an aqueous fluid (e.g., an aqueous body fluid) deposited on it. Hydrophilicity and wettability are typically defined by the fluid contact angle and the fluid seepage time, e.g., the seepage time through a nonwoven fabric. This is discussed in detail in the American Chemical Society publication (Copyright 1964), edited by Robert F. Gould, entitled "Contact Angle, Wettability and Adhesion." A substrate surface is said to be wetted by a fluid (i.e., hydrophilic) if the contact angle between the fluid and the surface is less than 90°, or if the fluid tends to spread naturally across the surface of the substrate (usually both conditions coexist). Conversely, if the contact angle is greater than 90° and the fluid does not spread naturally across the entire surface of the fibers, the substrate is considered "hydrophobic."

[0028] The "longitudinal direction" refers to the direction that extends substantially perpendicularly from one waist edge of an article to the opposite waist edge, and approximately parallel to the article's maximum straight-line dimension (line 80 in Figure 1). The "transverse direction" refers to the direction perpendicular to the longitudinal direction (line 90 in Figure 1).

[0029] "Inside" and "outside" refer to the relative positions of an element, the surface of an element, or a group of elements, respectively. "Inside" means that the element or surface is oriented toward the inside of the article, and "outside" means that the element or surface is oriented toward the outside of the article.

[0030] "Body-facing" and "clothing-facing" refer to the surface of an element or the relative location of a group of elements, respectively. "Body-facing" means that the surface is closer to the wearer during wear than the other surface of the element in the group. "Clothing-facing" means that the surface is oriented away from the wearer during wear. A clothing-facing surface may also be facing other clothing of the wearer (i.e., other items other than the wearable item), other items such as bedding, or the atmosphere.

[0031] The terms “comprise,” “comprising,” and “comprises” are non-restrictive terms, each identifying the presence of a feature (e.g., a component) described thereafter, but not excluding the presence of other features (e.g., elements, processes, or components known in the art or disclosed herein). These terms based on the verb “comprise” encompass the narrower terms “essentially consist of,” which exclude any unmentioned elements, processes, or components that substantially affect the manner in which the feature functions, and the term “consist of,” which excludes any unspecified elements, processes, or components.

[0032] An overview of an example diaper Figure 1 is a plan view showing an exemplary diaper 20 laid flat, with a portion of its structure cut out to more clearly illustrate the structure of the diaper. Since the structure of the present invention may be included in a wide variety of diapers or other absorbent articles such as pant-type diapers with pre-formed side seams, this diaper 20 is shown for illustrative purposes only. The side seams of the pant-type article can be opened by cutting or other means if it is desired to arrange them in a configuration similar to that shown in Figure 1 with the pant laid flat.

[0033] As shown in Figures 1 and 2, the absorbent article comprises a top sheet 24 on the side facing the wearer, a back sheet 25 on the side facing the clothing, and an absorbent core 28 between the top sheet 24 and the back sheet 25. The absorbent core 28 includes at least one layer 60 of superabsorbent polymer particles ("SAP") and a core wrap. The SAP layer is disposed between an upper core wrap layer 45 and a lower core wrap layer 46.

[0034] The SAP layer typically has a predetermined contour (outer perimeter) that is considered in the plane formed by the article when it is laid flat. This contour may be substantially rectangular, as shown in Figure 1, or it may be other shapes such as hourglass or dogbone. The absorbent core 28 may further include at least one longitudinally oriented channel-forming region 26, which is a substantially SAP-free region defined within the SAP layer. The channel-forming region(s)26 facilitate the distribution of fluid along the length of the absorbent article. An exemplary absorbent core structure is described in more detail below in relation to Figures 4-6.

[0035] The absorbent article of the present invention further comprises an upward capture and distribution system. An upward capture and distribution system as defined herein comprises all layers between the top sheet and the absorbent core. Typically, the upward capture and distribution system comprises at least an upward capture layer 52 directly below the top sheet, and optionally a distribution layer 54 between the capture layer and the absorbent core. The upward capture and distribution layer may also consist of a single layer, three layers, or more layers.

[0036] The upward capture and distribution system of the present invention preferably comprises one or more nonwoven fabric layers. The capture layer 52 may be, for example, a latex-bonded nonwoven fabric capture layer treated with a surfactant. Cross-linked cellulose fibers have been used in the past as a distribution layer having an air felt-free absorbent core, but these cellulose fibers are loose, i.e., unbonded, and therefore do not have the integrity of a nonwoven fabric. One object of the present invention is to remove unbonded cross-linked cellulose fibers without impairing the rate of fluid capture and distribution in the article. Therefore, the upward capture and distribution system does not contain such unbonded cross-linked cellulose fibers. Unbonded means that the fibers do not form a web that can be manipulated without a supporting layer such as a nonwoven fabric or airlaid, but rather the unbonded fibers form patches with only loose integrity, and the fibers can be easily separated by hand.

[0037] An example of a distribution layer that can be used in the present invention is a spunlace layer. However, other materials having fluid trapping and distribution properties as well as integrity, particularly nonwoven fabrics, may be used.

[0038] Suitable spunlace nonwovens include, for example, absorbent fibers, stiffening fibers, and elastic fibers, as disclosed in International Publication No. 2020 / 205485 (Peri et al.). Spunlace nonwovens may typically contain about 20 percent to about 75 percent absorbent fibers, about 1 percent to about 50 percent stiffening fibers, and about 10 percent to about 50 percent elastic fibers.

[0039] Any suitable absorbent fiber can be used. Some conventional absorbent fibers include cotton, rayon, or regenerated cellulose, or combinations thereof. In one embodiment, the absorbent fiber may include viscose cellulose fiber. The absorbent fiber may also include stapled fibers. The stapled length of the absorbent fiber may be in the range of about 20 mm to about 100 mm, or about 30 mm to about 50 mm, or about 35 mm to about 45 mm. As mentioned above, in addition to absorbent fibers, the spunlace of the present invention may also include stiffening fibers. Stiffening fibers can be used to help give structural integrity to the nonwoven fabric. Stiffening fibers can help increase the structural integrity of the nonwoven fabric in the machine direction and transverse machine direction, which can facilitate web operations during processing of the nonwoven fabric for incorporation into disposable absorbent articles. Any suitable stiffening fiber can be used. Some examples of suitable stiffening fibers include two-component fibers containing polyethylene and polyethylene terephthalate components or polyethylene terephthalate and copolyethylene terephthalate components. The components of a two-component fiber can be arranged in a core-sheath configuration, parallel configuration, eccentric core-sheath configuration, trefoil configuration, etc. In one particular embodiment, the rigid fiber may include a two-component fiber having a polyethylene / polyethylene terephthalate component arranged in a concentric core-sheath configuration with polyethylene as the sheath. In another embodiment, a single-component fiber may be used, and the single-component component may include polypropylene or polylactic acid (PLA). It is worth noting that these components, for example, polypropylene and polylactic acid, can also be used in two-component fibers.

[0040] Elastic fibers help spunlace maintain its permeability and cushioning properties. Suitable fibers that may be used include, in particular, hollow fibers, helical fibers, and / or hollow helical fibers. For example, elastic fibers can have linear densities of about 4 dtex to about 12 dtex, about 6 dtex to about 11 dtex, or about 8 dtex to about 10 dtex (specifically, including all values ​​within these ranges and any range defined by these ranges). In a particular embodiment, the elastic fiber may include hollow helical (HS) polyethylene terephthalate fibers with a linear density of about 10 dtex. In another particular embodiment, the elastic fiber may include circular polyethylene terephthalate fibers with a linear density of 6.7 dtex.

[0041] As shown in Figure 1, the absorbent material can be conceptually divided into an anterior lumbar region 36, a posterior lumbar region 38 opposite the first lumbar region 36, and a crotch region 37 located between the anterior lumbar region 36 and the posterior lumbar region 38. The crotch region, the anterior lumbar region, and the posterior lumbar region are defined here as each defining one-third of the length of the absorbent material along the longitudinal centerline 80. The longitudinal centerline 80 is an imaginary line that divides the diaper into two equal parts along its length. The transverse centerline 90 is an imaginary line perpendicular to the longitudinal centerline 80 in the plane of the diaper when it is laid flat, and passing through the center of the length of the diaper. The periphery of the diaper 20 is defined by the outer edge of the diaper. The longitudinal edge 13 of the diaper may extend approximately parallel to the longitudinal centerline 80 of the diaper 20, and the front waist edge 10 and rear waist edge 12 typically extend approximately parallel to the transverse centerline 90 of the diaper 20. However, these edges do not need to be straight and may be curved to better fit the wearer.

[0042] Furthermore, the absorbent article may include other optional but conventional elements not shown for simplification, such as a lotion applied to the body-facing surface of the posterior lumbar elastic feature, the anterior lumbar elastic feature, or a urine indicator located inside the backsheet that changes color upon contact with urine.

[0043] The top sheet 24, back sheet 25, and absorbent core 28 may be assembled in various known configurations, specifically by gluing, heat embossing, ultrasonic bonding, or a combination thereof. Exemplary diaper configurations are outlined in U.S. Patents 3,860,003, 5,221,274, 5,554,145, 5,569,234, 5,580,411, and 6,004,306.

[0044] The top sheet 24 is the absorbent portion of the article that comes into contact with the wearer's skin. At least a portion or all of the top sheet is liquid permeable, thereby allowing liquid bodily waste to easily penetrate through its thickness. Suitable top sheets can be made from a wide range of materials, such as porous foams, mesh foams, perforated plastic films, woven materials, nonwoven materials, natural fibers (e.g., wood fibers or cotton fibers), synthetic fibers or filaments (e.g., polypropylene fibers, or two-component PE / PP fibers, or mixtures thereof), or woven or nonwoven materials of combinations of natural and synthetic fibers. The top sheet may have one or more layers. The top sheet may be porous or non-porous, and may have any preferred three-dimensional features and / or multiple embossed areas (e.g., bonding patterns). Any part of the top sheet may be coated with skincare compositions, antimicrobial agents, surfactants, and / or other beneficial agents. The top sheet may be hydrophilic or hydrophobic, or may have hydrophilic portions or layers and / or hydrophobic portions or layers. If the top sheet is hydrophobic, pores will typically be present to allow bodily waste to pass through the top sheet.

[0045] The backsheet 25 is generally a portion of the absorbent article 20 that constitutes all or part of the surface of the absorbent article facing clothing. The backsheet 25 can be at least partially bonded to the topsheet 24, the absorbent core 28, or, if present, the lower capture and distribution layer 56 by any attachment method known to those skilled in the art. The backsheet prevents, or at least suppresses, bodily waste absorbed and trapped by the absorbent core from soiling articles such as bed sheets, underwear, and / or clothing. The backsheet is typically liquid-impermeable, or at least substantially liquid-impermeable.

[0046] Backsheets typically include thin, impermeable plastic films, such as thermoplastic films, with a thickness of approximately 0.01 mm to 0.05 mm. Backsheet materials can be breathable, allowing vapor to escape from absorbent articles while still preventing, or at least inhibiting, the passage of bodily waste through the backsheet. Breathable backsheets were measured using a PERMATRAN-W Model 101K (Mocon, Inc., Minneapolis, MN) or equivalent, according to the nonwoven fabric standard procedure NWSP 70.4.R0(15), with the experiment conducted in a controlled laboratory at 23°C ± 2°C and 50% RH ± 2% RH, and the instrument cell heated to 37.8°C (100°F), yielding 1,000–15,000 g / m². 2 / 24h, or 1,000-10,000g / m² 2 / 24h, or 1,500-10,000g / m² 2 It may have a water vapor transmission rate (WVTR) of 24 hours.

[0047] The backsheet 25 may also include a backsheet outer cover nonwoven fabric (not shown). The backsheet outer cover nonwoven fabric is typically a thin nonwoven material bonded to the outer surface of the backsheet film. The outer cover nonwoven fabric may thus form the surface of the backsheet that faces the clothing. The backsheet outer cover nonwoven fabric may include bonding patterns, openings, and / or three-dimensional features that can improve the feel of the backsheet.

[0048] The absorbent article 20 may also comprise an inner barrier leg cuff 34 and an outer leg cuff 32, as is known in the art. The inner barrier cuff 34 may extend upward from the surface of the article to provide retention of excrement, while the outer cuff is typically formed in the plane of the article's chassis, as defined by a top sheet and a back sheet. These cuffs are preferably elasticized using elastic threads 33, 35, as is known in the art, for example, as shown in the figure.

[0049] Furthermore, the absorbent article may further include a fastening system, such as an adhesive fastening system or a hook-and-loop fastening member, which may include a tape tab 42 disposed on the rear ear portion 40, such as an adhesive tape tab or a tape tab with a hook element, which cooperates with the landing zone 44 (e.g., a nonwoven web providing a loop in a hook-and-loop fastening system). Tape-type diapers typically have a rear ear portion 40 and a front ear portion 43, which are typically not present in pant-type absorbent articles that have pre-formed side seams.

[0050] Alternatively, the front and / or rear ear portions may be separate components attached to the absorbent article, or instead, they may be continuous with portions of the top sheet and / or back sheet, such that these portions form all or part of the front ear portion 43 and / or rear ear portion 40. A combination of the above is also possible, in which the front ear portion 43 and / or rear ear portion 40 is formed by portions of the top sheet and / or back sheet, while additional material is attached to form the entire front ear portion 43 and / or rear ear portion 40. The front and / or rear ear portions may be elastic or inelastic. The front ear portion 40 may also be applied as a separate component attached to the absorbent article, while the rear ear portion (or portion thereof) may be continuous with portions of the back sheet and / or top sheet, or vice versa.

[0051] Absorbent core 28 The absorbent core comprises at least one layer of superabsorbent polymer particles (SAP). SAP is a water-insoluble, water-swellable polymer capable of absorbing large amounts of fluid, as is known in the art. The term “superabsorbent polymer” as used herein refers to an absorbent material, typically a cross-linked polymer material, capable of absorbing at least 10 times its weight in 0.9% saline when measured using a centrifuge retention capacity (CRC) test, as shown in EDANA method NWSP241.0.R2(19). Specifically, the SAP may have a CRC value greater than 20 g / g, greater than 24 g / g, or 20–50 g / g, or 20–40 g / g, or 24–35 g / g. The SAP used in the present invention is described in more detail in the following sections.

[0052] The SAP is typically fixed within a core wrap that includes an upper core wrap layer and a lower core wrap layer, so that the absorbent core can be easily integrated with the rest of the chassis of the absorbent article in the processing line.

[0053] In the prior art, superabsorbent polymer particles are often mixed with cellulose fibers (air felt core), but the absorbent core of the present invention includes at least one SAP layer in which SAP particles are not mixed with cellulose fibers. Therefore, the resulting layer of absorbent material may have a reduced thickness in a dry state compared to conventional air felt-based absorbent cores. The reduced thickness helps to improve the fit and comfort of the absorbent article to the wearer. The absorbent core of the present invention preferably does not have to contain any unbound cellulose fibers at all (however, some cellulose fibers may be present in a bound form in a nonwoven fabric or tissue layer such as a spunlace layer). Many absorbent core designs can be used in the present invention. For example, if the core wrap contains a tissue paper layer, some cellulose fibers may be present within the core wrap. Therefore, although undesirable, the absorbent core may contain at least 45.10 -7 (cm 3 It is not excluded that a separate layer of cellulose fibers or a separate air felt / SAP mixed layer may be included, as long as it is different from the SAP layer having a urine permeability of (s) / g.

[0054] Various designs for absorbent cores containing layers of SAP without cellulose fibers have been proposed in the past; see, for example, U.S. Patent No. 5,599,335 (Goldman), European Patent No. 1,447,066 (Busam), International Publication No. 95 / 11652 (Tanzer), U.S. Patent Application Publication No. 2008 / 0312622(A1) (Hundorf), and International Publication No. 2012 / 052172 (Van Malderen). Specifically, the SAP printing techniques disclosed in U.S. Patent Application Publication No. 2006 / 024433 (Blessing), No. 2008 / 0312617, and No. 2010 / 0051166(A1) (both by Hundorf et al.) may be used.

[0055] A layer of SAP may typically be deposited on at least one layer of an absorbent core that serves as a substrate, such as a lower core wrap layer or an upper core wrap layer. In an SAP printing process such as that described in U.S. Patent Application Publication No. 2008 / 312,622(A1) (Hundorf), a continuous layer of SAP is obtained by depositing SAP on each of the core wrap layers in a pattern having absorbent material land regions separated by non-absorbent material bonding regions. The absorbent material land regions of the first layer substantially correspond to the non-absorbent material bonding regions of the second layer, and vice versa, so that a continuous layer of SAP is obtained when the two discontinuous layers are combined.

[0056] The absorbent core may include one or more adhesives, particularly auxiliary adhesives, applied between the inner surfaces of one or both core wrap layers and the SAP layer to bond and secure the SAP within the core wrap. Alternatively, as described in the Hundorf references above, a microfiber thermoplastic adhesive net may be used in the air felt-free core to secure the SAP. These adhesives are not shown in the diagram for simplification.

[0057] For example, other core structures including a high-loft nonwoven fabric substrate, such as a carded nonwoven fabric layer having a porous structure on which SAP particles are deposited, may also be used in this disclosure.

[0058] The SAP layers may be deposited as continuous layers within the core wrap. Alternatively, the SAP layers may exist discontinuously, for example, as individual pockets or stripes of absorbent material enclosed within the core wrap and separated from each other by material-free bonding areas.

[0059] The basis weight (amount deposited per surface unit) of the superabsorbent material can be varied to create a contour distribution of the superabsorbent material, particularly in the longitudinal direction to provide greater absorbency in the crotch region of the article, but also in the transverse direction of the core, or both.

[0060] The core wrap is formed by one or two substrate layers that sandwich the SAP particles and at least partially immobilize the SAP particles so that the absorbent core maintains its integrity. The upper core wrap layer 45 and the lower core wrap layer 46 are also referred to in the art as the core cover and dusting layer, respectively. These core wrap layers are typically low basis weight nonwoven fabrics (typically less than 20 gsm, particularly 8 gsm to 14 gsm) and may be SMS nonwoven fabrics (spunbond-meltblown-spunbond laminates) in particular, as is known in the art. The upper and lower core wrap layers may be any material that contains the absorbent material and can provide support for the absorbent material.

[0061] The core wrap layer may be made from the same or different materials, i.e., in a c-wrap configuration, from two nonwoven webs having the same or different properties. To simplify the structure and allow for a single longitudinal seal, the core wrap may also be made from a single continuous nonwoven web wrapped around a layer of absorbent material, in which case the upper and lower core wrap layers are made from the same web material.

[0062] Figures 4 to 6 show an exemplary absorber comprising an upper core wrap layer 45 oriented toward the top sheet, a lower core wrap layer 46 oriented toward the back sheet, and a layer of SAP 60 between the two core wrap layers. The shown absorbent core has two longitudinal edges 284, 286 formed by the core wrap, and a front transverse edge 280 and a rear transverse edge 282.

[0063] The core wrap layer is preferably longitudinally bonded by one or more longitudinal core wrap joints 29 to prevent the absorbent material from laterally deviating from the absorbent core. The core wrap layer may also optionally be transversely bonded to the front and rear sides of the absorbent core by one or more transverse core wrap joints 84. The core wrap layers can be bonded at least longitudinally opposite each other, as shown in Figure 2, but other bonding configurations are possible, particularly a C-wrap configuration in which one of the upper or lower core wrap layers is larger than the other, so that a flap can be folded around the absorbent material and attached to the other core wrap layer, as illustrated in Figure 6. The transversely extending portion of the upper core wrap layer 45 may surround the entire longitudinal edge 284, 286 of the core and may be bonded from the outside to the lower wrap layer 46 so that these flap portions are positioned on the garment-facing surface of the absorbent core. Alternatively, the flap portions on the longitudinal edge of the lower core wrap layer and adjacent flap portions may be folded onto the lateral edge of the core so that these flap portions are positioned on the body-facing surface of the absorbent core.

[0064] The upper core wrap layer 45 and the lower core wrap layer 46 typically enclose the SAP layer 60 at least partially or completely, providing drying and wetting fixation of the absorbent material. In addition, the SAP layer may be at least partially fixed on the upper core wrap layer 45 and / or the lower core wrap layer 46 (and / or on the lower capture and distribution layer 56 if present within the core wrap) by a hot melt adhesive applied between the substrate layer and the SAP, and / or by a thermoplastic fiber network applied on the SAP layer.

[0065] The absorbent core 28 optionally includes at least one channel-forming region 26 where substantially no absorbent material is present (in some cases, some superabsorbent particles may be deposited incidentally during core fabrication). The channel-forming region preferably does not extend to any side of the absorbent layer and is therefore completely surrounded by the absorbent material. The channel-forming region is typically elongated in the longitudinal direction and has a longitudinal length of 20% to 80%, or 20% to 70%, or 30% to 60% of the longitudinal length of the layer 60 of SAP (longitudinal length means length measured projected onto the longitudinal axis). The absorbent core may typically include a pair of channel-forming regions symmetrically arranged on each side of the longitudinal axis 80, and these channel-forming regions may be straight, curved, or a combination thereof. Such a pair of channel-forming regions may be separated, as shown in Figure 4. The channel-forming regions may also be connected, for example, at one or both of their ends to form a U-shape or an O-shape. Examples of channel-forming regions are disclosed in more detail in International Publication Nos. 2012170778(A1) and 2012170781 (Kreuzer et al.).

[0066] The upper core wrap layer 45 and the lower core wrap layer 46 are preferably bonded to each other over at least a portion of the length of the channel-forming region(s). This bond provides structural integrity of the channel in both dry and wet conditions. This bond may be provided using any known bonding technique known in the art, particularly adhesive bonding, thermal bonding, mechanical bonding, ultrasonic bonding, or any combination thereof. The adhesive may be applied, for example, typically by slot glue application or any other means, to the channel area on the upper inner and / or bottom inner sides of the core wrap, and then pressure is applied to the channel area to provide a good adhesive bond to these areas. Exemplary patent disclosures of such adhesive bonding processes can be found in International Publication No. 2012 / 170,798(A1) (Jackels et al.), European Patent No. 2,905,000 (Jackels et al.), and European Patent No. 2,905,001 (Armstrong-Ostle et al.) for air felt or air felt-free absorbent cores.

[0067] Other bonding methods, such as thermal bonding, mechanical bonding, and ultrasonic bonding, can also be used as additional or alternative bonding methods. For example, adhesive bonding can be reinforced by thermal bonding, mechanical bonding, or ultrasonic bonding. Such thermal bonding, mechanical bonding, or ultrasonic bonding can be applied to channels that pass outside the core wrap layer.

[0068] Typically, the channel bonds may generally have the same contour and shape as the channel-forming region 26 in which they are housed, but may be slightly smaller to allow for a safety margin (e.g., only a few millimeters) because some deviation from optimal alignment may occur during the high-speed process. The channel-forming region(s) form three-dimensional channels(s) while used as the rest of the absorbent layer, and the absorbent core absorbs fluid and swells. The channel-forming region(s) are optional in this invention.

[0069] The total amount of SAP present in the absorbent core is adapted to the needs of the intended wearer of the article. Newborn diapers require less SAP compared to infant or adult heavy incontinence diapers. The amount of SAP in the core may be, for example, about 2 g to 50 g, specifically 5 g to 40 g in a typical infant diaper. The average SAP areal density in the absorbent core may be, for example, at least 50, 100, 200, 300, 400, 500 g / m 2 or more, or 200 g / m 2 ~400 g / m 2 and can be. The average SAP areal density is the total amount of SAP in the core divided by the area defined by the perimeter of the SAP layer (including any channel-forming area, if present).

[0070] Superabsorbent particles 60 Superabsorbent polymer (SAP) is a water-swellable cross-linked polymer that is typically water-insoluble but can absorb large amounts of fluid. SAP is typically in particulate form so as to be flowable in the dry state, facilitating deposition onto the substrate. Typical SAP is made of polyacrylate polymers, but it is not excluded that other polymeric materials may also be used.

[0071] The absorbent core of the present invention comprises at least one layer of superabsorbent polymer particles having a urine permeability measurement value (「UPM」) exceeding 45 UPM units, where 1 UPM unit is 1×10 -7 (cm 3 ·s) / g. The UPM value is preferably at least 50 UPM units, particularly at least 55 UPM units or at least 60 UPM units. The SAP may preferably have a UPM in the range of 55 - 90 UPM units, particularly 55 - 80 UPM units, more specifically 60 - 75 UPM units, where 1 UPM unit is 1×10 -7 (cm 3The UPM value is (s) / g. The UPM value is measured according to the Urine Permeability Measurement (UPM) method described herein. The UPM method measures the flow resistance of the pre-swelled layer of superabsorbent polymer particles, i.e., the flow resistance is measured after filling the SAP with physiological saline. Thus, superabsorbent polymer particles having a high UPM value exhibit high permeability when a significant volume of the absorbent article is already wet with liquid exudate.

[0072] Unless otherwise specified, the values ​​provided herein for qualifying an SAP (e.g., SAP UPM, EFFC, T20...) refer to the properties of the entire SAP that make up the layer under consideration. For example, if two distinct layers of SAP are contained within an absorbent core and the SAP used in each layer is different, then at least one of these should have the UPM value described in the claims. If an SAP layer is formed by combining two intermediate layers of SAP (as is known with printed SAP technology, see below) and these SAPs are no longer distinct but form a single layer, then the SAP value refers to the entire SAP that makes up the combined SAP layer.

[0073] The superabsorbent polymer particles preferably have an effective capacity (EFFC) greater than 23 g / g, more preferably in the range of 23 g / g to 30 g / g, particularly in the range of 23.5 g / g to 29 g / g, or 24 g / g to 28 g / g, or 24.5 g / g to 27 g / g. The effective capacity (EFFC) is calculated by the following formula: EFFC = (CRC + AAP) / 2. The centrifugal retention capacity (CRC) is measured by the centrifugal retention capacity (CRC) test method described herein, and the absorption against pressure (AAP) is measured by the absorption against pressure (AAP) test method described herein. The SAP of the present invention may have an AAP of at least 22 g / g, or 23 to 24.5 g / g, or 24.0 to 24.5 g / g.

[0074] The SAP particles further have a bulk density of at least 0.5 g / mL, as measured according to the bulk density test method.

[0075] SAPs having the desired properties can be ordered from well-known SAP manufacturers, regardless of the manufacturing method. These SAPs used in the present invention can typically be obtained by surface crosslinking of precursor SAPs. Suitable precursor SAP particles can be obtained, for example, by reverse-phase suspension polymerization as described in International Publication 2015 / 041,784(A1) or European Patent No. 2,535,027(A1), or in U.S. Patents No. 4,340,706 and No. 5,849,816, or by spray-phase dispersion polymerization or other gas-phase dispersion polymerization as described in U.S. Patent Application Publications 2009 / 0192035, 2009 / 0258994, and 2010 / 0068520. In some embodiments, suitable precursor superabsorbent polymer particles can be obtained by production processes described in more detail on pages 12, line 23 to 20, line 27 of International Publication 2006 / 083584.

[0076] The precursor water-absorbing polymer particles are typically crosslinked internally, i.e., polymerization is carried out in the presence of a compound having two or more polymerizable groups that can be free-radical copolymerized into a polymer network structure. Useful crosslinking agents ii) include, for example, ethylene glycol dimethacrylate, diethylene glycol diacrylate, allyl methacrylate, trimethylolpropane triacrylate, triallylamine, tetraallyloxyethane as described in European Patent Application No. A 530 438, European Patents No. A 547 847, A 559 476, A 632 068, International Publications No. 93 / 21237, 03 / 104299, 03 / 104300, 03 / 104301, and German Patent No. A 103 31 450, German Patent No. A 103 31 456, and A 103 55 Examples include mixed acrylates further comprising acrylate groups and ethylenically unsaturated groups, as described in Patent No. 401, or crosslinking agent mixtures, such as those described in German Patent Nos. A 195 43 368, A 196 46 484, International Publication Nos. 90 / 15830 and 02 / 32962.

[0077] Preferably, the internal crosslinking agent ii) is a plurality of ethoxylated glycerols and / or propoxylated glycerols that are diacrylated, dimethacrylated, triacrylated, or trimaacrylated. Diacrylates and / or triacrylates of glycerols 3 to 10 (tuply) ethoxylated are particularly advantageous. More preferably, the crosslinking agent ii) is a diacrylate or triacrylate of glycerols 1 to 5 ethoxylated and / or propoxylated. Preferably, the internal crosslinking agent contains an acrylate group or an acrylamide group.

[0078] A detailed example of the production of SAP according to the present invention by surface crosslinking is provided in the following section titled "Method for Manufacturing SAP".

[0079] The SAP used in this invention may be surface crosslinked. Generally applicable surface crosslinking agents are thermally activated surface crosslinking agents. The term "thermally activated surface crosslinking agent" refers to a surface crosslinking agent that reacts only when exposed to high temperatures, typically around 150°C. Thermally activated surface crosslinking agents known in the prior art are, for example, difunctional or polyfunctional agents that can construct additional crosslinks between polymer chains of precursor superabsorbent polymer particles. Other thermally activated surface crosslinking agents include, for example, dihydric or polyhydric alcohols, or derivatives thereof that can form dihydric or polyhydric alcohols. Representative examples of such agents are alkylene carbonates, ketals, and diglycidyl ethers or polyglycidyl ethers. Furthermore, (poly)glycidyl ethers, haloepoxy compounds, polyaldehydes, polyols, and polyamines are also well-known thermally activated surface crosslinking agents. Crosslinking is based on reactions between functional groups contained in the precursor superabsorbent polymer particles, for example, esterification reactions between carboxyl groups (contained in the polymer) and hydroxyl groups (contained in the surface crosslinking agent).

[0080] Generally, the surface crosslinking agent is applied to the surface of the precursor superabsorbent polymer particles. Therefore, the reaction preferably occurs on the surface of the precursor superabsorbent polymer particles, resulting in improved crosslinking on the particle surface without substantially affecting the particle core. This makes the surface of the superabsorbent polymer particles harder.

[0081] The SAP of the present invention can be surface crosslinked, for example, using an alkylene carbonate as a surface crosslinking agent, preferably using a surface crosslinking solution containing deionized water. Preferably, the surface crosslinking solution is applied by stray coating. The heat treatment of the SAP of the present invention may be carried out at a high temperature, preferably above 185°C, more preferably 190°C to 205°C.

[0082] The SAP of the present invention is preferably classified after surface crosslinking and subsequent heat treatment, for example, using a sieving process. Preferably, the SAP of the present invention is sieved to a particle size in the range of 710 μm to 45 μm by measurement using EDANA NWSP 220.0R2(19).

[0083] The SAP K(t) test method described below is also useful for determining other SAP parameters that can be similarly advantageously used in the present invention. The SAP used in the core may also advantageously have an SAP T20 (time to reach 20 g / g absorption of less than 220 seconds) as measured by the SAP K(t) test method. Specifically, the SAP may have an SAP T20 of 100 to 220 seconds. The SAP T20 value may be less than 200 seconds, or less than 180 seconds, or less than 160 seconds. The time T20 may also be at least 100 seconds, 104 seconds, 120 seconds, or 140 seconds, and any combination of these upper and lower limits forming a range such as 100 to 200 seconds.

[0084] SAP intake (U20) at 20 minutes may be, in particular, at least 22 g / g, or at least 24 g / g, or at least 28 g / g, or at least 30 g / g, or 28 g / g to 60 g / g, or 30 g / g to 50 g / g, or 30 g / g to 40 g / g, as measured according to the SAP K(t) test method. SAP may be at least 1 × 10⁻⁶ g / g as measured according to the SAP K(t) test method. -8 cm 2 , or at least 2 × 10 -8 cm 2 , or at least 2.5 × 10 -8 cm 2 , or 3 × 10 -8 cm 2 ~1 × 10 -7 cm 2 , or 2 × 10 -8 cm 2 ~7×10 -8 cm 2 , or 2.5 × 10 -8 ~5×10 -8 cm 2It may have an effective transmittance (SAP K20) at the 20-minute mark.

[0085] SAP may also have a minimum effective transmittance ratio (SAP Kmin / SAP K20 ratio) greater than 0.75, 0.8, or 0.85, measured according to the SAP K(t) test method, to the transmittance at 20 minutes. In such embodiments, transient gel blocking is minimized, and liquid exudate can move rapidly through the voids between particles throughout the entire swelling process, particularly in the initial part of the swelling phase, which is most important for the first ejection.

[0086] The SAP of the present invention is typically selected from internally crosslinked and surface crosslinked polyacrylate and polyacrylic acid polymers. The superabsorbent polymer can be internally crosslinked, i.e., polymerization is carried out in the presence of a compound having two or more polymerizable groups that can be free radical copolymerized into a polymer network. Exemplary superabsorbent polymer particles of the prior art are described, for example, in International Publications 2006 / 083584, 2007 / 047598, 2007 / 046052, 2009 / 155265, and 2009 / 155264. Preferably, the SAP particles include crosslinked polymers of polyacrylic acid or salts thereof, or polyacrylate or derivatives thereof.

[0087] SAP particles may be relatively small in their dry state (their longest dimension less than 1 mm) and may be approximately circular in shape, but granules, fibers, flakes, spheres, powders, plates, and other shapes and forms are also known to those skilled in the art. Generally, SAP may be in the form of spherical particles.

[0088] At least a portion of the SAP particles can be aggregated, for example, as taught in European Patent No. 3,391,961(A1) (Kamphus, P&G). Aggregated superabsorbent polymer particles can be obtained by a variety of methods. Aggregated particles can be obtained, for example, by agglomerating precursor particles with an interparticle crosslinking agent reacted with the polymer material of the precursor particles to form crosslinks between the precursor particles, as disclosed, for example, in U.S. Patents Nos. 5,300,565, 5,180,622 (both Berg), 5,149,334, 5,102,597 (both Roe), and 5,492,962 (Lahrman). Other methods for obtaining aggregated SAP particles are described, for example, in European Patent No. 3056521(B1) (Kim et al.), European Patent No. 1512712(B1) (Koji et al.), U.S. Patent No. 10414876(B2) (Jang et al.), U.S. Patent No. 7429009(B2) (Nagasawa et al.), European Patent No. 220224911 (Higashimoto et al.), and European Patent No. 2011803(B1) (Handa et al.).

[0089] Aggregated superabsorbent polymer particles can also be obtained by a method comprising the steps of providing superabsorbent polymer particles and mixing the superabsorbent polymer particles with a solution containing water and a polyvalent salt having a valency of 3 or higher. This method is further disclosed in European Patent No. 2,944,376(A1). Specifically, the superabsorbent polymer particles may comprise at least 5% by weight, or at least 10% by weight, or at least 20% by weight, or at least 30% by weight, or at least 40% by weight, or at least 50% by weight of aggregated SAP. A method for producing aggregated superabsorbent polymer particles, including edge-modified and / or surface-modified clay slabs, is disclosed in European Patent No. 3391963.

[0090] The surface of the SAP particles may be coated. SAP may also contain surface-modified and / or edge-modified clay platters. Preferably, the clay platters are montmorillonite, hectorite, laponite, or mixtures thereof. Preferably, the clay platters are laponite. SAP may contain 0.1 to 5% by weight of surface-modified and / or edge-modified clay platters compared to the weight of the precursor superabsorbent polymer particles.

[0091] Upward detection and distribution system ("Upward ADS") Referring to Figures 1 and 2, the absorbent article 20 of the present disclosure comprises an upper capture and distribution system (hereinafter referred to as the “upper ADS”). The ADS comprises all layers 52, 54 (one or more layers) disposed between the top sheet 24 and the absorbent core 28. The upper ADS can rapidly capture bodily fluids such as urine and efficiently distribute them to the absorbent core 28. The upper ADS may consist of a single layer or may have two or more layers, which may form a single structure or remain separate layers, and these layers may be bonded to each other, for example, by thermal bonding, adhesive bonding, or a combination thereof. A single structure as used herein can be formed of several sublayers having distinct properties and / or compositions, but these sublayers are mixed in some way at boundary regions so that, instead of clear boundaries between the sublayers, it is possible to identify regions where different sublayers transition to each other. Such a single structure is typically constructed by forming different sublayers in a continuous manner on top of other layers, for example, using airlaid or wet-laid deposition. Typically, no adhesives are used between the sublayers of the monolithic material. However, in some cases, adhesives and / or binders may be present in smaller amounts, typically in multilayer materials formed by separate layers.

[0092] As previously noted, cross-linked cellulose fibers have been used in the art to form a distribution layer deposited on a latex-bonded nonwoven trapping layer. Such cross-linked cellulose fibers are not bonded to one another and, in contrast to the nonwoven or airlaid layer, do not possess inherent cohesion. This causes the cross-linked cellulose fibers to form agglomerates during use, reducing the benefits of such a distribution layer.

[0093] According to the present invention, the upper ADS is substantially free of unbound cross-linked cellulose fibers. "Substantially free" means that such cross-linked cellulose fibers form less than 20% by weight, preferably less than 10% by weight, of the upper ADS, and more preferably, the upper ADS is free of any unbound cross-linked cellulose fibers. More generally, the upper ADS preferably consists of one or more nonwoven layers. While the upper ADS is preferably free of unbound cellulose fibers, it may contain cellulose fibers formed in a web, such as an airlaid nonwoven layer containing a mixture of cellulose fibers and synthetic fibers.

[0094] The upper ADS may comprise two layers: a first layer 52 directly beneath the top sheet and a second layer 54 between the first layer and the absorbent core. A suitable example of a double-layer ADS is disclosed in U.S. Patent No. 20210106471(A1) (Yuan et al., P&G), which discloses a first layer that is a carded air-through nonwoven fabric and a second layer that is an airlaid nonwoven fabric. While not theoretically bound, thermoplastic fibers provide a more open structure while improving the structural integrity of the fluid distribution layer. Cellulose fibers provide liquid storage capacity and a resilient, open structure that allows for rapid recovery of the fluid distribution layer even after repeated rough handling.

[0095] The first layer 52 may be a known trapping nonwoven fabric layer in the art, such as an air-through bonded carded nonwoven fabric having a basis weight of 20 gsm to 100 gsm, particularly 30 gsm to 80 gsm. Such a trapping layer is typically made of synthetic fibers hydrophilically treated with a surfactant. The trapping layer 52 may also be a latex-bonded, hydrophilically treated nonwoven fabric.

[0096] The second layer 54 of the upper ADS, if present, may be selected from a variety of nonwoven materials, for example, an airlaid nonwoven containing a mixture of cellulose and synthetic fibers combined to form a single nonwoven web.

[0097] The second layer 54 may also include, or consist of, a spunlace nonwoven fabric which has been found to provide good fluid handling, integrity, and flexibility. Suitable spunlace may have a basis weight in the range of about 40 grams / m² (gsm) to about 200 gsm, preferably about 70 gsm to about 120 gsm. The spunlace typically includes a plurality of absorbent fibers, a plurality of stiffening fibers, and a plurality of elastic fibers integrated into the spunlace. Spun lace is, -Approximately 20 percent to approximately 75 percent absorbent fibers, -Approximately 1 percent to approximately 50 percent stiffened fibers, - May contain approximately 10 percent to 50 percent elastic fibers.

[0098] A suitable example of spunlace is disclosed, for example, in International Publication No. 2020 / 205,485(A2) (Peri et al., P&G).

[0099] Other materials for the second layer are further possible, such as spunbond nonwovens or spunbond-meltblown-spunbond ("SMS") nonwovens. SMS may mean a 3-layer "sms" nonwoven material, a 5-layer "ssmms" nonwoven material, or any reasonable variation thereof, where lowercase letters indicate individual layers and uppercase letters indicate similar adjacent layer formations.

[0100] The upper ADS of the present invention typically does not contain superabsorbent material. The upper ADS of the present invention may have an overall basis weight in the range of about 20 gsm to about 220 gsm, particularly about 40 gsm to about 160 gsm, calculated on average over the entire area of ​​the upper ADS. In some embodiments, the upper ADS according to the present invention contains less than 40 gsm of cellulose fibers. The basis weight of the first layer may be determined to balance the capture and distribution performance with the overall thickness of the absorbent article. If the upper ADS includes a capture layer 52 and a distribution layer 54, the distribution layer may typically have a basis weight approximately the same as or higher than that of the capture layer. The basis weight can be calculated as usual by dividing the weight of the layer by its area.

[0101] Downward capture and distribution layer (downward "ADL") 56 The articles of the present invention may optionally include a capture and distribution layer (referred to herein as “downward ADL”) between the SAP layer and the backsheet. The use of downward ADL is optional to provide additional temporary storage while minimizing or preventing the perception of moisture from the outer surface of the absorbent article.

[0102] The lower ADL 56 is typically located between the absorbent core 28 and the backsheet, as shown in Figure 3A. In other words, the lower ADL is typically positioned between the lower core wrap layer 46 and the liquid-impermeable backsheet 25. Furthermore, this structure is the simplest to manufacture because it does not require any changes to the existing absorbent core manufacturing process, and the lower ADL is additionally inserted between the absorbent core and the backsheet.

[0103] Alternatively, the lower ADL 56' may, in some cases, be used as the lower core wrap layer 46 and may be in direct contact with the SAP layer 60 (so that there is no separate lower core wrap layer 46). In this case, the upper core wrap layer 45 and the lower ADL 56' may partially or completely surround the SAP layer 60. This embodiment is shown in Figure 3B for an alternative absorbent article 20'. In this structure, the core wrap is formed by the upper core wrap layer 45 and the lower ADL 56'. However, such a structure has a drawback because the lower ADL 56' needs to be larger and longer than necessary to cover the entire layer of absorbent material 28, resulting in additional material costs. The basis weight of the lower ADL, and therefore the material cost, is typically a multiple of the low basis weight SMS nonwoven fabric that can be used as the lower core wrap layer 46. Therefore, it may be preferable for the absorbent article to have a lower core wrap layer 46 and a separate lower ADL 56, as shown in Figures 3A and 3C.

[0104] In another alternative configuration, as shown in Figure 3C, the SAP absorbent material 60 and the lower ADL 56'' may be partially or completely encapsulated between the upper core wrap layer 45 and the lower core wrap layer 46. In this alternative configuration, the lower capture and distribution layer 56'' is positioned between the SAP layer 60 and the lower core wrap layer 46 and is therefore integrated into the absorbent core. However, this embodiment does not exclude the fact that it adds complexity to the core manufacturing process and that some superabsorbent particles may penetrate the pores of the ADL and affect its fluid handling properties.

[0105] The lower ADL may consist of a single layer, in particular a single nonwoven layer having the required properties, as shown. Alternatively, the lower ADL may be a multilayer structure such as a laminate, or an integrated layer including integrated sublayers, as long as the multilayer structure has the required properties. Such a multilayer structure may also include two sublayers, each having a different width, and as a result, the lower ADL has an increased basis weight in the longitudinally extending region in the center of the article where both sublayers are present. To avoid misunderstanding, if the absorbent article comprises a separate lower core wrap layer 46, the basis weight is 20 g / m². 2 Any such separate lower core wrap layer having a basis weight less than the lower ADL will not be considered as part of the lower ADL.

[0106] The lower ADL56 may include, or consist of, a nonwoven fabric layer, which can function as a temporary reservoir for liquids that have flowed through the SAP layer because they were not absorbed sufficiently rapidly by the absorbent material.

[0107] The additional layers provided to absorbent articles generally increase the thickness and bulk of the article, thereby reducing wearer comfort. Furthermore, the increase in bulk, particularly between the wearer's legs, is generally undesirable. Therefore, it may be desirable to limit the caliper in the lower ADL to 0.3 mm, optionally, within a range of, for example, up to 4 mm, as measured at a pressure of 0.85 kPa according to the caliper measurement method described herein.

[0108] The basis weight for lower ADL is typically (though not mandatory) 20 g / m². 2 ~100g / m 2 , or 25g / m 2 ~80g / m 2 , or 30g / m 2 ~50g / m 2It can be within this range. The basis weight of the lower ADL is typically homogeneous throughout its length and width (i.e., longitudinally and transversely) if it consists of at least a single layer. The basis weight of the material is typically provided by the supplier and can also be calculated by dividing the weight of the lower ADL by its surface area.

[0109] The lower ADL may have a smaller longitudinal and / or transverse extension than the SAP layer 60, so that the absorbent material layer extends beyond the lower ADL in the longitudinal and / or transverse directions. The SAP layer 60 may also extend beyond the upper ADS in the longitudinal and / or transverse directions.

[0110] Alternatively, the lower ADL may have a greater longitudinal and / or transverse extension than the absorbent material layer, so that the lower ADL extends beyond the absorbent material layer in the longitudinal and / or transverse directions. This may be desirable when the absorbent material layer is in direct contact with the lower ADL (i.e., there is no lower substrate layer between the absorbent material layer and the lower ADL), as shown in Figure 3B. In such a configuration, the SAP layer may be partially placed on either the upper core wrap layer 46 or the lower ADL 56, or on each layer.

[0111] The lower ADL may preferably not contain a superabsorbent polymer. The lower ADL may include or consist of a nonwoven layer. The nonwoven layer may be any type of conventional nonwoven and fiber, as long as the required properties are met. Carded nonwovens (made from staple fibers) have been found to be particularly preferred. Carded nonwovens may be calendered or air-through bonded, as is known in the art. The nonwoven layer may also be a spunbond or meltblown nonwoven web (made from continuous fibers), or a nonwoven having spunbond and meltblown layers (e.g., SMS, SMMS, SMSS, etc.).

[0112] Air-through bonded nonwoven fabrics generally have high loft. Therefore, they possess a porous structure that provides void volume for absorbing and temporarily retaining liquids. At the same time, they offer softness and do not have excessively high bending stiffness.

[0113] The lower ADL may contain at least 30% by weight, optionally at least 50% by weight, and up to 100% by weight, crimped fibers, based on the total weight of the lower capture and distribution layers. The crimped fibers may have two-dimensional crimping, three-dimensional crimping, or a combination of two- and three-dimensional crimping. Typically, in the carding process, all or most of the fibers are crimped two-dimensionally (zigzag), while eccentric two-component fibers can typically be crimped three-dimensionally. The crimped fibers may help drive the bulkiness and void volume of the nonwoven fabric.

[0114] The ADL layer, particularly its nonwoven fabric layer, may be made from synthetic fibers or may consist of synthetic fibers. Particularly preferred synthetic fibers are those made from polyolefins (e.g., polyethylene, polypropylene, or mixtures or combinations thereof), polyethylene terephthalate (PET), co-PET, polylactic acid (PLA), polyhydroxyalkanoids (PHA), or combinations or mixtures thereof. The fibers may be continuous fibers or staple fibers.

[0115] The fibers may be single-component fibers or multi-component fibers such as two-component fibers. If the fibers included in the lower ADL are two-component fibers, they have a core-sheath structure, and the core components have a higher melting point than the sheath components.

[0116] The fibers included in the lower ADL are preferably staple fibers. Similar to nonwoven webs made of continuous fibers, nonwoven webs of staple fibers are preferably air-through bonded. In addition to water-flow entanglement (spunlace) or air-through bonding, nonwoven webs of staple fibers may or may not undergo some local bonding by heat and / or pressure (e.g., point bonding / calendering), introducing local bonding regions where the fibers fuse with each other.

[0117] Regardless of whether the nonwoven web is made of continuous fibers or staple fibers, local bonding should, however, not bond an excessively large surface area, thereby adversely affecting the loft and void volume of the nonwoven web. Preferably, the total bonded area obtained by local bonding by heat and / or pressure (in addition to water entanglement or air-through bonding) should not be greater than 20%, greater than 15%, or greater than 10% of the total surface area of ​​the nonwoven web.

[0118] Through-air bonding (used interchangeably with the term "air-through bonding") refers to the process of bonding staple fibers or continuous fibers by forcing air through a nonwoven web, where the air is hot enough to melt (or at least partially melt, or melt until the surface of the fiber is sufficiently tacky) the polymer of the fiber, or, if the fiber is a multi-component fiber, hot enough to melt (or at least partially melt, or melt until the surface of the fiber is sufficiently tacky) one of the polymers from which the fiber of the nonwoven web is made. The air velocity is typically 30–90 meters per minute, and the residence time can be up to 6 seconds. The melting and re-solidification of the polymer provides bonding between different fibers.

[0119] Hot air melts the low-melting-point polymer components of staple fibers, continuous fibers, or multi-component fibers, thereby forming bonds between the staple fibers and solidifying and integrating the layers of staple fibers into the web.

[0120] The lower ADL may contain multi-component fibers that at least partially form the nonwoven fabric. The fibers of the nonwoven fabric contained in the lower ADL may contain at least 30% by weight, or at least 40% by weight, or at least 50% by weight, or at least 70% by weight, or at least 90% by weight, or 100% by weight of multi-component fibers, based on the total weight of the nonwoven fabric contained in the lower capture and distribution layers. The multi-component fibers may be binary fibers, such as core sheath or parallel binary fibers.

[0121] Alternatively, the nonwoven fabric layer included in or forming the lower ADL may contain single-component fibers. The fibers of the nonwoven fabric included in the lower trapping and distribution layer may contain at least 30% by weight, or at least 40% by weight, or at least 50% by weight, or at least 70% by weight, or at least 90% by weight, or 100% by weight of single-component fibers, based on the total weight of the nonwoven fabric included in the lower trapping and distribution layer. The nonwoven fabric web included in or forming the lower ADL may contain a mixture of single-component fibers and multi-component fibers.

[0122] Generally, fiber dtex (related to fiber diameter) directly affects the pore size of the material, and therefore, in particular, capillary pressure and permeability / penetration of the material, as well as material seepage. For a given basis weight, lower dtex results in lower permeability and higher capillary pressure. The lower trapping and distribution layer may contain at least 50% by weight of fibers having a denier of less than 10 dtex, or at least 70% by weight, or at least 80% by weight, and up to 100% by weight of fibers.

[0123] In particular, if the lower ADL contains or consists of synthetic fibers that are inherently hydrophobic, the lower ADL may advantageously contain a hydrophilic agent. Any conventional hydrophilic treatment that provides a hydrophilic agent can be used. Typically, webs such as nonwovens may be coated on the outside directly or via an oil / emulsion with a surfactant. Alternatively, as known in the art, a hydrophilic melt additive can be added to the polymer melt used to produce the fibers. A hydrophilic melt additive is an amphiphilic molecule having a hydrophilic head and a hydrophobic tail. The hydrophilic head is oriented toward the surface of the adhesive and thus provides the hydrophilic characteristics of the adhesive, while the hydrophobic head remains in the polymer matrix.

[0124] Hydrophilic melt additives are typically incorporated into a masterbatch in pellet form rather than being incorporated by homogeneous mixing in the molten polyolefin. Commercially available examples of hot melt additives particularly compatible with propylene-based metallocene catalyst polyolefins include Techmer's PPM 15560 (hydrophilic PP masterbatch) and Brij S2 (Croda). Further, in order of decreasing priority, Brij S10 (Croda), Unithox 450, Unithox 720, and Unithox 750 (Baker Hughes) can be used. PPM 15560 is preferably used at a dosage of 0.5 weight percent of the masterbatch, while Brij S2 and Brij S10 are preferably used at a dosage of 2 weight percent of the active substance. Techmer's Techsurf® melt additives, used to impart hydrophilicity to polyolefin fibers, nonwovens, and specialty plastic applications, are useful in this invention.

[0125] U.S. Patent No. 6,146,757 discloses a hydrophilic fusion additive comprising a blend of a first wetting agent and a second wetting agent. The first wetting agent is at least one water-insoluble, nonionic alkoxylated alkylphenol, and the second wetting agent is at least one compound selected from the group consisting of alkoxylated aliphatic alcohols and water-soluble, nonionic, non-hydrolyzable polyoxyalkylene-modified organosilicone polymers.

[0126] The lower ADL56 and the lower core wrap layer 46 can, advantageously, both be hydrophilic. The lower ADL layer may optionally be less hydrophilic than the lower core wrap layer.

[0127] package Multiple absorbent articles according to the present invention can be packaged for transport and sale. At least 50%, preferably all, of the articles in the package may be of the present invention. The articles may be folded and packaged as is known in the art. The package may be, for example, a plastic bag or a cardboard box. Before packaging, diapers may be folded in half along a transverse axis, with the ear loops folded inward. Absorbent articles may be packaged under compression to reduce the package size while providing an appropriate number of absorbent articles per package. Packaging absorbent articles under compression allows caregivers to easily handle and store the package, while also potentially reducing distribution costs due to package size for manufacturers.

[0128] Therefore, absorbent articles can be compressed and packaged with an in-bag compression ratio of at least 10%, particularly 10% to 50%, and especially 20% to 40%. As used herein, “in-bag compression ratio” is the number obtained by subtracting from 1 the number obtained by dividing the stack height (“in-bag stack height” or “IBSH”) measured under in-bag compression of 10 folded articles by the stack height of 10 folded articles of the same type before compression, and then multiplying by 100, i.e., (1-IBSH / stack height before compression) × 100 reported as a percentage. Naturally, the in-bag stack does not need to have exactly 10 articles, but rather the number obtained by multiplying the measured value for the stack height of articles in the package by the number of articles in the stack, and then multiplying by 10. The method used to measure the in-bag stack height will be described in more detail in the test procedure. Articles before compression are sampled from the production line between the folding unit and the stack packaging unit. The stack height before compression is measured by taking 10 articles before compression and packaging and measuring their stack heights as shown for IBSH.

[0129] The packages for absorbent articles of this disclosure may have in-bag laminate heights of less than 110 mm, less than 105 mm, less than 100 mm, less than 95 mm, less than 90 mm, specifically the specified range, and all increments of 0.1 mm within or within the specified range (the in-bag laminate height test is described in detail in U.S. Patent Application Publication 2014 / 0143180(A1)). With respect to each of the values ​​shown in the preceding sentence, it may be desirable to have in-bag laminate heights greater than 60, or greater than 70 mm, or greater than 75 mm, or greater than 80 mm. Alternatively, the packaging of absorbent articles of this disclosure may have an internal stacking height in a bag of 60mm to 110mm, 65mm to 110mm, 70mm to 110mm, 75mm to 105mm, or 80mm to 100mm, specifically, the specified range and all 0.1mm increments within or formed by the specified range.

[0130] Bio-based materials The components of the disposable absorbent articles of the present invention (i.e., diapers, pants, sanitary napkins, panty liners, etc.) are as described in U.S. Patent Application Publication No. 2007 / 0219521(A1) by Hird et al., published on September 20, 2007; U.S. Patent Application Publication No. 2011 / 0139658(A1) by Hird et al., published on June 16, 2011; and U.S. Patent Application Publication No. 2011 / 0139658(A1) by Hird et al., published on June 16, 2011. The present invention may be at least partially composed of biosource-containing materials described in Hird et al.'s No. 0139657(A1), published June 23, 2011, No. 2011 / 0152812(A1), published June 16, 2011, and No. 2011 / 0139662(A1), published June 16, 2011. These components may include, but are not limited to, a top sheet nonwoven fabric, a back sheet film, a back sheet nonwoven fabric, a barrier leg cuff nonwoven fabric, an absorbent material, upper and lower core wrap layers, an adhesive, a fastener hook, and a fastener landing zone nonwoven fabric, as well as a film base. For example, the upper and / or lower capture and distribution layers of the present invention may at least partially contain biosource-containing materials.

[0131] The components of a disposable absorbent article may contain biobase content values ​​of approximately 10% to approximately 100%, in another embodiment approximately 25% to approximately 75%, and in yet another embodiment approximately 50% to approximately 60%, using Method B of ASTM D6866-10.

[0132] To determine the biobase content of any disposable absorbent article components by applying the methodology of ASTM D6866-10, it is necessary to obtain representative samples of the disposable absorbent article components for testing. Therefore, the components of the disposable absorbent article can be ground into fine particles of less than approximately 20 mesh using a known grinding method (e.g., a Wiley® mill), and a representative sample of a suitable mass can be taken from the randomly mixed particles.

[0133] Examples and Data SAP material: Table 1 below shows the properties of different SAPs used to prepare the diaper examples. Comparative Example SAP1 ("COMP SAP1") and Comparative Example SAP2 ("COMP SAP2") were both Aquaic CA L825 manufactured by Nippon Shokubai Co., Ltd. in Himeji, but were taken from different packaging. The properties were measured as further shown in the "Test Methods" section below.

[0134] [Table 1]

[0135] SAP1-5 according to the present invention were obtained by surface crosslinking of either COMP SAP1 or COMP SAP2 to increase the urine permeability measurement ("UPM") value. As can be seen from Table 1, surface crosslinking can significantly increase the UPM value while moderately reducing EFFC. A detailed explanation of the crosslinking method is further described in the following section, "Method for Preparing SAP1-5".

[0136] Examples of absorbent articles for those with lower ADL (Activities of Daily Living) Using COMP SAP1, SAP1, and SAP2, absorbent articles in the form of diapers containing an air felt-free core (similar to those commercially used in Pamper® diapers) were handcrafted. All diapers had a 30 gsm air-through binding (ATB) trapping layer and a 50 gsm spunlace (SL) as a distribution layer. A lower ADL (carded air-through binding "C-TAB") was also placed between the absorbent core and the backsheet. The only difference between the four examples of diapers tested was the nature and amount of SAP used in the absorbent core, as shown in Table 2 below.

[0137] The diapers thus obtained were tested according to the C-SABAP method (Curved-Speed ​​of Acquisition with Balloon Applied Pressure). C-SABAP determines the time required to capture a predetermined amount of saline solution while the diaper is held in a slightly curved position, placed on a latex film inflated with compressed air at 2.07 kPa (0.30 psi), and monitored by a digital pressure gauge. The capture rate was measured four times for each type of diaper. Four sprays of 75 mL of colored saline solution (0.9 wt%) were applied sequentially at a rate of 15 mL / s, with a 5-minute interval between each spray. The capture time for each spray was recorded from the time when fluid application began until the time when no fluid was present on the surface of the TS on the application area. The liquid was delivered to the diaper from the front of the absorbent core at a distance of 102 mm and placed in the center in the transverse direction. A smaller capture time number is desirable, indicating a faster absorption rate of the absorbent material.

[0138] The capture time in seconds for these four consecutive saline spurts was measured for eight diapers per leg, and the average results, along with the standard deviation in parentheses, are shown in Table 2 below.

[0139] [Table 2]

[0140] As can be seen from Table 2, the diapers of the present invention (Examples 2-4) have a shorter first capture time when using SAP with a UPM value exceeding 50 UPM units. Examples 2 and 3 further provided comparable performance for the second, third, and fourth extrusions, even with lower or equivalent total core EFFC values ​​compared to Comparative Example 1. Example 3 has the same total EFFC as Comparative Example 1, but shows a shorter capture time for each of the four extrusions.

[0141] The data show that, at equivalent total core capacity (total core EFFC), higher permeability SAP is more effective in reducing capture time. Even at lower total core EFFC, capture rate could be improved, at least partially, compared to the comparative SAP. While not bound by theory, it is thought that an appropriate balance of capacity and permeability can provide the desired performance in air felt-free diapers with an up-capturing system that does not contain unbound cross-linked cellulose fibers.

[0142] Absorbent articles for which there is no lower ADL Further test diapers were handcrafted using COMP SAP2, SAP3, SAP4, and SAP5 as shown in Table 3 below and tested as previously described. The trapping layer was 43gsm resin-bound (RB) carded nonwoven fabric. The distribution layer was 75gsm spunlace with 40% 1.3dtex viscose, 30% 4.4dtex PET / CoPET, and 30% 10dtex PET HS. The diapers in this series of tests did not have a lower trapping and distribution layer.

[0143] [Table 3]

[0144] Examples 6 and 7 of the present invention demonstrate that using SAP with a higher UPM provides equivalent capture rates for four test ejections, even when the total core EFFC is significantly lower than in Comparative Example 5.

[0145] Example 8 uses SAP3 with a very high UPM value, but the recorded capture rate is not significantly different from Examples 6 and 7, or is only slightly lower than in the case of the fourth capture time. Example 9 shows that performance could be significantly improved by using an additional 1.6g of SAP3. While we do not wish to be bound by theory, it is thought that for a given SAP, EFFC and UPM are roughly inversely correlated. Therefore, SAP3 has very high permeability, but its EFFC is significantly lower than, for example, SAP4 or SAP5, resulting in a lower core capacity overall for the same amount of SAP. The lower core capacity may be a problem for load conditions.

[0146] Example 6 provided the best balance between reduced volume and increased permeability while using 0.3 g less SAP than Example 5. The performance sweet spot is thought to be found in units of approximately 50 to 100 UPM, preferably 55 to 90 UPM, in which case it is possible to reduce the amount of superabsorbent material without affecting the performance of the absorbent core.

[0147] Method for creating SAP1-5 Examples SAP1 to SAP5 of the present invention were obtained by surface crosslinking treatment of COMP SAP1 and COMP SAP2 with ethylene carbonate (EC) (application of a surface crosslinking agent in a fluidized bed), as detailed below.

[0148] Laboratory conditions: Ambient conditions: 23±2℃ and relative humidity 45±10%.

[0149] Surface cross-linking chemical: EC: Ethylene carbonate ("EC") anhydrous, 99% purity / Sigma-Aldrich.

[0150] Device: The ProCell Labsystem Pro, manufactured by Glatt Ingenieurtechnik GmbH, includes a Coater Module GF3 (reactor [B206010] with process insert [B203010]), a transition housing [B203000] and a Wurster insert (70 mm in diameter and 190 mm in height), a Wurster bottom "Type B" and a cyclone [F121490], or similar equipment.

[0151] The spray nozzle was a 2-stream bottom spray nozzle (Schlick 2-stream nozzle, model #970 form 0S4). The nozzle cap was adjusted to be flush with the tip of the nozzle pipe. Project number: W51505, 2013.

[0152] The system operates without feedback flow of fine powder from the cyclone.

[0153] Pump: Ismatec pump ISM404B with pump head ISM720A.

[0154] Hose: Silicone (peroxide cured) ID=2.06mm

[0155] Preparation of 300g of surface crosslinking agent solution: The original EC bottle was placed in a circulating oven at 60°C for 2 hours to liquefy. 299.93 g of deionized water was placed in a beaker equipped with a magnetic stirrer. Using a pipette with an advanced combi-tip, a 0.057 cm³ stirring was performed. 3 An amount of EC (equivalent to 0.080g) was taken from the bottle and transferred to a beaker.

[0156] The solution was stirred at room temperature for 5 minutes.

[0157] 264g of the prepared solution was taken out, transferred to another beaker, and used for coating. The beaker containing the EC aqueous solution was placed on a balance during the coating process to control the spray rate of the coating.

[0158] Equipment preparation: Before starting the coating process, close and start the equipment, then open the pressurized air valve. Set the equipment to 65 Nm of fluidized air at a set temperature of 70°C. 3 The system was preheated for approximately 30 minutes with an airflow rate of / h.

[0159] Pump Calibration: Peristaltic pumps with silicone hoses are calibrated to a flow rate of 2.5 g / min ± 0.1 g / min using approximately 20 g of deionized water.

[0160] coating: 600.0g ± 1.0g of starting SAP (COMP SAP1) was placed in a GF3 process container.

[0161] I closed the devices and started them up in the following order according to their respective settings. 1) Start the fan and set it to 65 Nm 3 The settings were set to / h and the product temperature to 70°C. 2) The nozzle air was started at a spray pressure of 1.2 bar. 3) Heating was started (product temperature setpoint 70°C). 4) Once the temperature inside the coated container reached approximately 70°C, the liquid port of the spray nozzle was connected to the ethylene carbonate solution via a hose attached to the pump head, and the pump was started. The solution was sprayed onto Comp AGM 1 in the reactor at a spray rate of approximately 2.5 g / min ± 0.1 g / min. Throughout the experiment, the product temperature was controlled within the range of 68°C to 72°C, and the fluidizing air flow rate was set to 60 to 70 m³. 3 The temperature was controlled within / h. The spray rate of the coating agent, the temperature of the fluidized air or the product temperature, and the flow rate of the fluidized air were set so that the water-absorbing polymer particles would not become sticky and no additional drying would be required after the coating was complete.

[0162] In total, 264.0 g ± 0.2 g of EC aqueous solution was sprayed onto the Comp AGM 1 during coating. The instrument was then shut down as follows. 1) The heater was turned off. 2) The fan was stopped. 3) The nozzle's air jet was stopped. 4) The coated superabsorbent polymer particles were discharged from the reaction vessel into a stainless steel bowl and weighed to the nearest 0.1 g. The material in the expansion chamber above the reaction vessel and the material in the seal area between the reaction vessel and the expansion chamber were not collected and were discarded. If the weight of the coated superabsorbent polymer particles collected in the stainless steel bowl deviates by more than 15% by weight from the weight of Comp AGM (here 600.0 g ± 1.0 g), the material should be discarded and the experiment repeated.

[0163] Heating / curing: Coated superabsorbent polymer particles were evenly dispersed on two Teflon-coated baking trays (41 x 31 x 10 cm). The baking trays were covered with aluminum foil and placed in a circulating oven preheated to 192°C. The oven temperature was controlled within the range of 191-193°C. The coated superabsorbent polymer particles remained in the oven for the curing times listed in Table 3 below. Afterward, the coated superabsorbent polymer particles were removed from the oven and allowed to cool to room temperature, remaining on the aluminum foil-covered tray.

[0164] After the coated superabsorbent polymer particles were cooled to room temperature, they were sieved using a sieve with a diameter of approximately 20 cm. A stack of sieves with the following mesh sizes (from top to bottom): 710 μm, 45 μm, and a collection pan was used. The superabsorbent particle sample was loaded onto the top sieve (i.e., 710 μm) and sieved for 3 minutes at 1 mm / g using a sieving machine (e.g., the "AS 400 Control" available from Retsch GmbH (Haan, Germany)).

[0165] The fractions of coated superabsorbent polymer particles ranging in size from 45 μm to 710 μm represent the respective SAP samples listed in Table 1.

[0166] After sieving, SAP pre2 was heat-treated / cured again in a circulating oven. The oven was preheated to 192°C. The temperature inside the oven was controlled within the range of 191-193°C. The obtained sample was SAP2, and the total heat treatment / curing time was 102 minutes.

[0167] [Table 4]

[0168] Note: The desired UPM level can be easily adjusted by a longer or shorter duration of heat treatment / curing, with longer heat treatment / curing durations resulting in higher UPM, i.e., higher SAP permeability.

[0169] SAP3-5 were obtained in the same way as SAP1-2, but starting from COMP SAP2, the following curing conditions were used.

[0170] [Table 5]

[0171] Test method Centrifugal Retention Volume (CRC) Test Method CRC measures the amount of liquid absorbed by superabsorbent polymer particles that free-swell in excess saline. CRC is measured according to the EDANA method NWSP 241.0.R2(19).

[0172] Pressure Absorption (AAP) Test Method AAP is measured at an applicable pressure of 0.7 psi according to the EDANA method NWSP 242.0.R2(19).

[0173] Effective Capacity (EFFC) The effective capacity represents the average of the centrifugal retention capacity (CRC) and pressure absorption (AAP) values ​​of the superabsorbent polymer particles.

[0174] The effective capacity (EFFC) is calculated using the following formula: EFFC = (CRC + AAP) / 2.

[0175] Bulk density testing method For bulk density testing methods, refer to EDANA method NWSP 251.0.R2(19).

[0176] Urine permeability measurement (UPM) method Laboratory conditions: This test must be conducted in a climate-controlled room under standard conditions of 23°C ± 2°C and 45% ± 10% relative humidity.

[0177] Urine permeability measurement system This method measured the transmittance of the swollen hydrogel layer 1318. The equipment used in this method is described below.

[0178] Figure 7 shows a transmittance measurement system 1000, comprising a constant static water head reservoir 1014, an open tube 1010 for air intake, a vent hole 1012 with a stopper for refilling, a laboratory rack 1016, a conduit 1018 with a flexible tube 1045 equipped with a Tygon tube nozzle 1044, a stopcock 1020, a cover plate 1047, and a support ring 1040, a receiving container 1024, a balance 1026, and a piston / cylinder assembly 1028.

[0179] Figure 8 shows a piston / cylinder assembly 1028, including a metal weight 1112, a piston shaft 1114, a piston head 1118, a lid 1116, and a cylinder 1120. The cylinder 1120 is made of clear polycarbonate (e.g., Lexan®) and has an inner diameter p of 6.00 cm (area = 28.27 cm²). 2The inner cylinder wall 1150 is smooth. The bottom 1148 of the cylinder 1120 faces a stainless steel screen cloth (ISO9044 material 1.4401, mesh size 0.038 mm, wire diameter 0.025 mm) (not shown), which was stretched biaxially to a taut state before being attached to the bottom 1148 of the cylinder 1120. The piston shaft 1114 is made of clear polycarbonate (e.g., Lexan®) and has an overall length q of approximately 127 mm. The central part 1126 of the piston shaft 1114 has a diameter r of 22.15 (±0.02) mm. The upper part 1128 of the piston shaft 1114 has a diameter s of 15.8 mm and forms the shoulder 1124. The lower portion 1146 of the piston shaft 1114 has a diameter t of approximately 5 / 8 inch (15.9 mm) and is threaded for securely screwing into the central hole 1218 (see Figure 9) of the piston head 1118. The piston head 1118 is perforated and made of transparent polycarbonate (e.g., Lexan®) and covered with similarly stretched stainless steel screen cloth (ISO9044 material 1.4401, mesh size 0.038 mm, wire diameter 0.025 mm) (not shown). The weight 1112 is made of stainless steel, has a central hole 1130, slides onto the upper part 1128 of the piston shaft 1114, and stops on the shoulder 1124. The combined weight of the piston head 1118, piston shaft 1114, and weight 1112 is 596 g (±6 g), which corresponds to 0.30 psi across the internal area of ​​the cylinder 1120. The total weight can be adjusted by drilling a stop hole in the central axis 1132 of the piston shaft 1114 to remove material and / or by providing a cavity to add weight. The cylinder lid 1116 has a first lid opening 1134 at its center to vertically align the piston shaft 1114, and a second lid opening 1136 near its edge 1138 to introduce fluid into the cylinder 1120 from a constant static head reservoir 1014.

[0180] A first linear indicator mark (not shown) is scribing radially along the upper surface 1152 of the weight 1112, and the first linear indicator mark is transverse with respect to the central axis 1132 of the piston shaft 1114. A corresponding second linear indicator mark (not shown) is scribing radially along the upper surface 1160 of the piston shaft 1114, and the second linear indicator mark is transverse with respect to the central axis 1132 of the piston shaft 1114. A corresponding third linear indicator mark (not shown) is scribing along the central portion 1126 of the piston shaft 1114, and the third linear indicator mark is parallel to the central axis 1132 of the piston shaft 1114. A corresponding fourth linear indicator mark (not shown) is scribing radially along the upper surface 1140 of the cylinder cover 1116, and the fourth linear indicator mark is transverse with respect to the central axis 1132 of the piston shaft 1114. Furthermore, a corresponding fifth linear indicator mark (not shown) is scribed along the lip 1154 of the cylinder cover 1116, and the fifth linear indicator mark is parallel to the central axis 1132 of the piston shaft 1114. A corresponding sixth linear indicator mark (not shown) is scribed along the outer cylinder wall 1142, and the sixth linear indicator mark is parallel to the central axis 1132 of the piston shaft 1114. The alignment of the first, second, third, fourth, fifth, and sixth linear indicator marks allows the weight 1112, piston shaft 1114, cylinder cover 1116, and cylinder 1120 to be repositioned in the same orientation relative to each other in each measurement.

[0181] The detailed specifications of cylinder 1120 are as follows: Outer diameter u of cylinder 1120: 70.35 mm (±0.05 mm) Inner diameter p of cylinder 1120: 60.0 mm (±0.05 mm) The height of cylinder 1120 is ν: 60.5 mm. The height of the cylinder must not be less than 55.0 mm.

[0182] The specifications of the cylinder cover 1116 are as follows: Outer diameter w of cylinder cover 1116: 76.05 mm (±0.05 mm) Inner diameter of cylinder cover 1116: 70.5 mm (±0.05 mm) Thickness y of cylinder lid 1116, including lip 1154: 12.7 mm Thickness of cylinder cover 1116 excluding lip 1154: z: 6.35 mm Diameter of the first lid opening 1134: 22.25 mm (±0.02 mm) Diameter b of the second lid opening 1136: 12.7 mm (±0.1 mm) Distance between the center of the first lid opening 1134 and the center of the second lid opening 1136: 23.5 mm

[0183] The detailed specifications for weight 1112 are as follows: Outer diameter c:50.0mm Diameter d of the center hole 1130: 16.0 mm Height e: 39.0 mm

[0184] The detailed specifications of piston head 1118 are as follows: Diameter f: 59.7mm (±0.05mm) Height g: 16.5 mm. The height of the piston head must not be less than 15.0 mm. The outer holes 1214 (total of 14) have a diameter h of 9.30 (±0.25) mm, are evenly spaced, and their centers are 23.9 mm from the center of the central hole 1218. The inner holes 1216 (total of 7) have a diameter i of 9.30 (±0.25) mm, the inner holes 1216 are evenly spaced, and their centers are 13.4 mm from the center of the central hole 1218. The central hole 1218 has a diameter j of approximately 5 / 8 inch (15.9 mm) and is threaded to receive the lower portion 1146 of the piston shaft 1114.

[0185] Before use, the stainless steel screen (not shown) on the piston head 1118 and cylinder 1120 should be inspected for clogging, holes, or overstretching and replaced if necessary. A urine permeability analyzer with a damaged screen may give inaccurate UPM results and should not be used until the screen is replaced.

[0186] A 5.00 cm mark 1156 is scribble on cylinder 1120 at a height k of 5.00 cm (±0.05 cm) above a screen (not shown) attached to the bottom 1148 of cylinder 1120. This marks the liquid level to be maintained during the analysis. Maintaining an accurate and constant fluid level (hydrostatic pressure) is important for measurement accuracy.

[0187] A constant static head reservoir 1014 is used to supply saline solution 1032 to the cylinder 1120 and to maintain the level of saline solution 1032 at a height k of 5.00 cm above a screen (not shown) attached to the bottom 1148 of the cylinder 1120. The bottom 1034 of the intake tube 1010 is positioned to maintain the level of saline solution 1032 in the cylinder 1120 at the required height k of 5.00 cm during measurement; that is, the bottom 1034 of the air tube 1010 is on a plane 1038 approximately in line with the 5.00 cm mark 1156 on the cylinder 1120, above the receiving container 1024 and placed on the cover plate 1047 and support ring 1040 (the inner opening of the circle is 64 mm or more in diameter).

[0188] The cover plate 1047 and support ring 1040 are components used in an instrument used for the method “K(t) test method (dynamic effective transmittance and intake rate measurement test method)” as described, for example, in International Publication No. 2021 / 188330, and are called “Zeitabhangiger Durchlassigkeitsprufstand” or “Time Dependent Permeability Tester,” instrument number 03-080578, and are commercially available from BRAUN GmbH (Frankfurter Str. 145, 61476 Kronberg, Germany). Detailed drawings are also available upon request.

[0189] Proper height alignment of the intake tube 1010 and the 5.00 cm mark 1156 on the cylinder 1120 is important for the analysis. A suitable reservoir 1014 consists of a jar 1030 including a horizontally oriented L-shaped conduit 1018 connected to a flexible tube 1045 (e.g., a Tygon tube to which a nozzle and reservoir outlet can be connected) and a Tygon tube nozzle 1044 (with an inner diameter of at least 6.0 mm and a length of about 5.0 cm) for fluid delivery, a vertically oriented opening tube 1010 for introducing air at a fixed height within the constant static head reservoir 1014, and a stoppered vent 1012 for refilling the constant static head reservoir 1014. Tube 1010 has an inner diameter of about 12 mm but at least 10.5 mm. A conduit 1018, positioned near the bottom 1042 of the constant static head reservoir 1014, includes a stopcock 1020 for starting / stopping the supply of saline solution 1032. The outlet 1044 of the delivery flexible tube 1045 is dimensioned (e.g., 10 mm outer diameter) to be inserted through a second lid opening 1136 of the cylinder lid 1116, with its end positioned below the surface of the saline solution 1032 in the cylinder 1120 (after a height of 5.00 cm of saline solution 1032 has been achieved in the cylinder 1120). The intake tube 1010 is held in place by an O-ring collar 1049. The constant static head reservoir 1014 may be positioned on a laboratory reck 1016 at a suitable height relative to the height of the cylinder 1120. The components of the constant static head reservoir 1014 are sized to rapidly fill the cylinder 1120 to the required height (i.e., static head) and maintain this height over the measurement period. The constant static head reservoir 1014 must be capable of supplying saline solution 1032 at a flow rate of at least 2.6 g / second for at least 10 minutes.

[0190] The piston / cylinder assembly 1028 is positioned on a support ring 1040 in a cover plate 1047 or a preferred alternative rigid stand. The saline solution 1032 passing through the piston / cylinder assembly 1028 containing the swollen hydrogel layer 1318 is collected in a receiving container 1024 located below (but not in contact with) the piston / cylinder assembly 1028.

[0191] The receiving container 1024 is positioned on a balance 1026 with an accuracy of at least 0.001 g. The digital output of the balance 1026 is connected to a computerized data acquisition system 1048.

[0192] Preparation of reagents (not shown) Jayco Synthetic Urine (JSU) 1312 is used in the swelling phase (see UPM procedure below), and 0.118 M sodium chloride (NaCl) solution 1032 is used in the flow phase (see UPM procedure below). The following preparations are for a standard 1-liter volume. For preparations of volumes other than 1 liter, all quantities should be measured as appropriate.

[0193] JSU: Fill a 1 L volumetric flask with distilled water to 80% of its volume and place an electromagnetic stirring rod inside the flask. Separately, using weighing paper or a beaker, weigh the following amounts of dry ingredients to within ±0.01 g using a chemical balance and add them quantitatively to the volumetric flask in the same order as listed below. The solution is stirred on a suitable stirring plate until all solids have melted, the stirring rod is removed, and the solution is diluted with distilled water to a volume of 1 L. The stirring rod is reinserted, and the solution is stirred on the stirring plate for several more minutes.

[0194] Amount of salt needed to produce 1 liter of Jayco synthetic urine Potassium chloride (KCl) 2.00g Sodium sulfate (Na2SO4) 2.00g Ammonium hydrogen diphosphate (NH4H2PO4) 0.85g Ammonium phosphate, dibasic ((NH4)2HPO4) 0.15g Calcium chloride (CaCl2) 0.19g - [or calcium chloride hydrate (CaCl2·2H2O) 0.25g] Magnesium chloride (MgCl2) 0.23g - [or magnesium chloride hydrate (MgCl2·6H2O) 0.50g]

[0195] To expedite preparation, combine potassium chloride, sodium sulfate, ammonium hydrogen diphosphate, ammonium phosphate (dibasic), and magnesium chloride (or magnesium chloride hydrate) and dissolve in 80% distilled water in a 1 L volumetric flask. Dissolve calcium chloride (or calcium chloride hydrate) separately in approximately 50 mL of distilled water (e.g., in a glass beaker) until the other salts are completely dissolved, then transfer the calcium chloride solution to a 1 L volumetric flask. Add 1 L (1000 mL ± 0.4 mL) of distilled water and stir the solution for several minutes. Jayco synthetic urine can be stored in a clean plastic container for 10 days. Do not use the solution if it becomes cloudy.

[0196] 0.118 M sodium chloride (NaCl) solution: 0.118 M sodium chloride is used as saline solution 1032. Using weighing paper or a beaker, weigh 6.90 g (±0.01 g) of sodium chloride and quantitatively transfer it to a 1 L volumetric flask (1000 mL ± 0.4 mL). Fill the flask to capacity with distilled water. Add a stirring rod and mix the solution on a stirring plate until all solids are dissolved.

[0197] The conductivity of the prepared Jayco solution must be in the range of approximately 7.48–7.72 mS / cm, and the conductivity of the prepared 0.118 M sodium chloride (NaCl) solution must be in the range of approximately 12.34–12.66 mS / cm (measured, for example, via a COND 70 INSTRUMENT without cell #50010522 equipped with xs instruments Cell VPT51-01 C=0.1, or via LF320 / set #300243 equipped with WTW TetraCon325, or COND330i, #02420059 equipped with WTW TetraCon325). The surface tension of each solution must be in the range of 71–75 mN / m (measured, for example, via a Kruess surface tensile meter K100 equipped with a Pt plate).

[0198] Exam preparation Using a solid reference cylinder weight (not shown) (50 mm in diameter; 128 mm in height), a caliper gauge (not shown) (measuring range 25 mm, accuracy 0.01 mm, maximum piston pressure 50 g; e.g., Mitutoyo Digimatic Height Gage) is set to a reading of 0. This operation is conveniently performed on a smooth, horizontal bench (not shown) of at least approximately 11.5 cm × 15 cm. The piston / cylinder assembly 1028, free of superabsorbent polymer particles, is positioned below the caliper gauge (not shown), and the reading L1 is recorded in 0.01 mm increments.

[0199] The constant still water head reservoir 1014 is filled with saline solution 1032. The bottom 1034 of the inhalation tube 1010 is positioned during measurement to maintain the top (not shown) of the liquid meniscus (not shown) in the cylinder 1120 at the 5.00 cm mark 1156. Proper height alignment of the inhalation tube 1010 at the 5.00 cm mark 1156 on the cylinder 1120 is important for the analysis.

[0200] The receiving container 1024 is placed on the balance 1026, and the digital output of the balance 1026 is connected to the computerized data acquisition system 1048. A cover plate 1047 with a support ring 1040 is positioned above the receiving container 1024.

[0201] UPM Procedure Using a chemical balance, weigh 1.5 g (±0.05 g) of superabsorbent polymer particles onto suitable weighing paper or weighing aids. The moisture content of the superabsorbent polymer particles is measured according to the EDANA moisture content test method NWSP 230.0.R2(15) or via a moisture analyzer (Mettler Toledo HX204, drying temperature 130°C, starting superabsorbent weight 3.0 g (±0.5 g), stopping criterion 1 mg / 140 sec). If the moisture content of the superabsorbent polymer particles is greater than 3% by weight, dry the superabsorbent polymer particles until the moisture level is <3% by weight, for example, in an oven at 105°C for 3 hours or in an oven at 120°C for 2 hours.

[0202] An empty cylinder 1120 is placed on a horizontal benchtop (not shown), and superabsorbent polymer particles are quantitatively transferred into the cylinder 1120. For example, the superabsorbent polymer particles are evenly dispersed onto a screen (not shown) attached to the bottom 1148 of the cylinder 1120, while the cylinder 1120 is rotated with the assistance of a (manual or electric) turntable (e.g., a Schuett petriturn-E or petriturn-M). For the most precise results, it is important to evenly disperse the particles onto the screen (not shown) attached to the bottom 1148 of the cylinder 1120. After the superabsorbent polymer particles have been evenly dispersed onto the screen (not shown) attached to the bottom 1148 of the cylinder 1120, the particles must not adhere to the inner cylinder wall 1150. With the lip 1154 of the lid 1116 facing the piston head 1118, the piston shaft 1114 is inserted through the first lid opening 1134. The piston head 1118 is carefully inserted into the cylinder 1120 to a depth of several centimeters. Then, the lid 1116 is placed on the upper rim 1144 of the cylinder 1120, taking care to keep the piston head 1118 away from the superabsorbent polymer particles. The weight 1112 is positioned on the upper part 1128 of the piston shaft 1114, so that it is placed on the shoulder 1124, thereby aligning the first and second linear indicator marks. Next, the lid 1116 and piston shaft 1126 are carefully rotated so that the third, fourth, fifth, and sixth linear indicator marks are aligned with the first and second linear indicator marks. Then, the piston head 1118 is gently pressed down (through the piston shaft 1114) and placed on the dry superabsorbent polymer particles. Proper placement of the lid 1116 prevents the weight from sticking and ensures even distribution of the weight on the hydrogel layer 1318.

[0203] Swelling phase: A frit disc 1310 having "coarse" or "very coarse" porosity, with a diameter of at least 8 cm (e.g., 8-9 cm in diameter) and a thickness of at least 5.0 mm (e.g., 5-7 mm in thickness) (e.g., Chemglass Inc. #CG 201-51, coarse porosity; or e.g., Robu 1680 with zero porosity) is placed in a flat-bottomed petri dish 1314, and JSU 1312 is added by pouring JSU 1312 into the center of the frit disc 1310 until the JSU 1312 reaches the top surface 1316 of the frit disc 1310. The height of the JSU must not exceed the height of the frit disc 1310. It is important to avoid any air or bubbles trapped in or beneath the frit disc 1310.

[0204] The entire piston / cylinder assembly 1028 is lifted and placed on the frit disc 1310 in the petri dish 1314. The JSU 1312 from the petri dish 1314 passes through the frit disc 1310 and is absorbed by superabsorbent polymer particles (not shown) to form a hydrogel layer 1318. The amount of JSU 1312 available in the petri dish 1314 should be sufficient for all swelling phases. If necessary, more JSU 1312 may be added to the petri dish 1314 during the hydration period to maintain the liquid level of JSU 1312 on the upper surface 1316 of the frit disc 1310. After a period of 60 minutes, the piston / cylinder assembly 1028 is removed from the frit disc 1310, taking care not to let the hydrogel layer 1318 lose any JSU 1312 or incorporate any air during this procedure. The piston / cylinder assembly 1028 is placed under a caliper gauge (not shown), and the reading L2 is recorded in 0.01 mm increments. If the reading changes over time, only the initial value is recorded. The thickness L0 of the hydrogel layer 1318 is determined from L2 to L1 in 0.1 mm increments.

[0205] The piston / cylinder assembly 1028 is moved to the support ring 1040 in the cover plate 1047. The constant still water head reservoir 1014 is positioned so that the conduit nozzle 1044 is positioned through the second lid opening 1136. The measurement is started in the following order: a) The stopcock 1020 of the constant still water head reservoir 1014 is opened so that the saline solution 1032 reaches the 5.00 cm mark 1156 on the cylinder 1120. This level of saline solution 1032 should be achieved within 10 seconds of opening the stopcock 1020. b) Once 5.00 cm of saline solution (1032 units) is reached, start the data collection program.

[0206] Using a computer 1048 attached to a balance 1026, the amount of saline solution 1032 passing through the hydrogel layer 1318 in grams (with an accuracy of 0.001 g) is recorded at 20-second intervals for 10 minutes. At the end of the 10 minutes, the stopcock 1020 on the constant still water head reservoir 1014 is closed.

[0207] Data collected from 60 seconds into the experiment until the end will be used for the UPM calculation. Data collected before 60 seconds will not be included in the calculation.

[0208] Each 20-second period after the first 60 seconds of the experiment (time t (i-1) ~t i Regarding ), each flow velocity Fs (t) (Unit: g / s) and time t (1 / 2)t The midpoint of each (in seconds) is calculated according to the following formula:

[0209]

number

[0210] Each time interval (t (i-1) ~t i ) flow velocity Fs (t) is the time interval (t (i-1) ~t i ) time t (1 / 2)t The plot is drawn with respect to the midpoint. The intercept is calculated as Fs(t=0).

[0211] Calculation of the intercept: The intercept is calculated through the optimal regression line, for example, as follows: The equation for the intercept of regression line a is:

[0212]

number

[0213]

number

[0214] Calculation of urine permeability measurement value Q: Using the intercept Fs(t=0), Q is calculated according to the following formula.

[0215]

number

[0216] [Table 6]

[0217] SAP K(t) test method This method determines the time-dependent effective permeability SAP K(t) and uptake rate of gel layers formed from hydrogel-forming superabsorbent polymer particles or absorbent structures containing such particles under confining pressure. The purpose of this method is to evaluate the ability of gel layers formed from hydrogel-forming superabsorbent polymer particles or absorbent structures containing them to capture and distribute body fluids when the polymer is present at high concentrations in the absorbent article and is subjected to mechanical pressures that typically occur during the use of the absorbent article. Effective permeability is calculated using Darcy's law and the steady-state flow method (see below). See also, for example, "Absorbency," ed. By PK Chatterjee, Elsevier, 1982, Pages 42-43, and "Chemical Engineering Vol. II, Third Edition," JMCoulson and JFRichardson, Pergamon Press, 1978, Pages 122-127.

[0218] Unlike previously published methods, the sample is not pre-swollen, and therefore the hydrogel is not formed by pre-swelling hydrogel-forming superabsorbent polymer particles in synthetic urine; however, the measurement is initiated using a dry structure. The instrument used for this method is called "Zeitabhangiger Durchlassigkeitsprufstand" or "Time Dependent Permeability Tester" (instrument number 03-080578), is commercially available from BRAUN GmbH (Frankfurter Str. 145, 61476 Kronberg, Germany), and is described below. Operating instructions, wiring diagrams, and detailed technical drawings are also available upon reasonable request.

[0219] A detailed description of the instrument (dynamic effective transmittance and acquisition rate measurement system) and its handling is further disclosed in International Publication No. 2015 / 041784(A1) (Peri et al., P&G).

[0220] Record the average values of T20, T80%, K20, U20, and Kmin / K20 from three repetitions, according to the required accuracy known to those skilled in the art.

[0221] Others As used herein, the terms "comprise(s)" and "comprising" are open-ended and each identifies the presence of the subsequently recited features, e.g., elements, but does not exclude the presence of other features, e.g., elements known in the art or disclosed herein. These terms based on the verb "comprise" are to be construed to include the more restrictive terms "consisting essentially of", which excludes any element, step, or ingredient not recited that materially affects the way the feature is performed, and "consisting of", which excludes any element, step, or ingredient not specified. None of the preferred or exemplary embodiments described below limit the claims, unless specifically stated otherwise. Words such as "typically", "usually", "preferably", "advantageously", "specifically", etc. also modify features not intended to limit the claims, unless specifically shown to the contrary. The dimensions and values disclosed herein are not to be understood as being strictly limited to the recited exact numerical values. Instead, unless otherwise indicated, each such dimension is intended to mean both the recited value and the functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm".

[0222] All documents cited herein, including any patents or patent applications that are cross-referenced or related, and any patent applications or patents for which this application claims priority or the benefit thereof, are hereby incorporated by reference in their entirety, unless expressly excluded or limited. The citation of any document shall not be construed as an admission that it is prior art with respect to any invention disclosed or claimed herein, nor shall it be construed as teaching, suggesting, or disclosing any such invention, whether alone or in combination with any other reference or references. Further, any meaning or definition of a term in this document that conflicts with any meaning or definition of the same term in a document incorporated by reference shall be governed by the meaning or definition given to the term in this document.

[0223] Although specific embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that various other changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, all such changes and modifications within the scope of the invention are intended to be covered by the appended claims.

Claims

1. Absorbent article (20), - Liquid permeable top sheet (24), - An absorbent core (28) comprising an upper core wrap layer (45), a lower core wrap layer (46), and a layer (60) of superabsorbent polymer particles disposed between the upper core wrap layer and the lower core wrap layer, - An upward capture and distribution system (52, 54), wherein the upward capture and distribution system consists of one or more layers disposed between the top sheet and the absorbent core, and the upward capture and distribution system substantially does not contain unbound crosslinked cellulose fibers, - Includes a liquid-impermeable backsheet (25), The superabsorbent polymer particles, when measured by the UPM method described herein, have a density of at least 45.10 －７ (cm ３ An absorbent article (20) having a urine permeability measurement value (UPM) of s / g.

2. The superabsorbent polymer particles are 55.10 －７ ~90.10 －７ (cm ３ The absorbent article according to claim 1, having a UPM in the range of s) / g.

3. The absorbent article according to claim 1 or 2, wherein the superabsorbent polymer particles have an effective volume (EFFC) greater than 23 g / g, and the effective volume is measured as described herein.

4. The absorbent article according to claim 3, wherein the superabsorbent polymer particles have an EFFC in the range of 23.5 g / g to 29 g / g.

5. The absorbent article according to any one of claims 1 to 4, wherein the superabsorbent polymer particles are not mixed with cellulose fibers.

6. The absorbent article according to any one of claims 1 to 5, wherein the upward capture and distribution system includes at least one spunlace layer.

7. The absorbent article according to any one of claims 1 to 6, wherein the upward capture and distribution system includes a first layer and a second layer, the first layer being closer to the top sheet, the second layer being closer to the absorbent core, the first layer being a nonwoven capture layer (52), and the second layer being a nonwoven distribution layer (54).

8. The absorbent article according to claim 7, wherein the second layer (54) is a spunlace nonwoven fabric.

9. The absorbent article according to any one of claims 1 to 8, further comprising a downward trapping and distribution layer (56) between the layer of superabsorbent polymer particles and the back sheet, wherein the downward trapping and distribution layer includes or consists of a nonwoven fabric layer, particularly a carded nonwoven fabric layer.

10. The absorbent article according to claim 9, wherein the downward capture and distribution layer has a basis weight of 20 gsm to 100 gsm, preferably 30 gsm to 50 gsm.

11. The absorbent article according to claim 9 or 10, wherein the downward capture and distribution layer (56) comprises a surfactant coating and / or a hydrophilic melting additive.

12. The absorbent article according to any one of claims 8 to 11, wherein the downward trapping and distribution layer (56) is disposed between the lower core wrap layer (46) and the back sheet (25), and both the downward trapping and distribution layer (56) and the lower core wrap layer (46) are hydrophilic, but the downward trapping and distribution layer (56) is less hydrophilic than the lower core wrap layer (46).

13. The absorbent article according to any one of claims 1 to 12, wherein at least some of the superabsorbent polymer particles are fixed by a thermoplastic fiber net on at least one of the upper core wrap layer (45) or the lower core wrap layer (46).

14. The absorbent article according to any one of claims 1 to 13, wherein the layer (60) of superabsorbent polymer particles includes at least one longitudinally extending channel (26) that does not contain superabsorbent polymer particles.

15. The absorbent article according to any one of claims 1 to 14, wherein the superabsorbent polymer particles are obtained by surface crosslinking of a precursor SAP, and the precursor SAP is preferably internally crosslinked.

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