Buckling type paper diaper

Abstract

The utility model discloses a buckling type paper diaper (200) which comprises a film-free bottom layer (280), and the film-free bottom layer (280) is at least provided with a single-piece base material. The monolithic substrate has at least a first nonwoven layer (281) of a spunbonded structure located at the bottom of the filmless base layer (280), a second nonwoven layer (282) of a melt-blown structure located on the first nonwoven layer (281), and a third nonwoven layer (283) of a spunbonded structure located on the second nonwoven layer (282), the gram weight ratio of the first nonwoven layer (281), the second nonwoven layer (282), and the third nonwoven layer (283) being 20: 3: 20. When the outer surface of the first non-woven layer (281) of the monolithic substrate is configured with a polymer layer (285) formed of an ethylene-acrylic copolymer, the outer surface of the third non-woven layer (283) is configured with a printed layer (284).

Description

Technical Field

[0001] This utility model relates to the field of disposable hygiene products, and in particular to a snap-on diaper with a membrane-free bottom layer. Background Technology

[0002] Fastener diapers are not only an indispensable item for infants and toddlers in their daily lives, but also suitable for adult users with specific needs. They not only provide a comfortable fit, but also effectively absorb waste from both infants and adults, keeping their private areas dry.

[0003] Currently, there are many bottom film layers on the market, such as polyethylene (PE) film, PE breathable film, and non-woven composite film. These materials have poor breathability, and if used for a long time, the area where they are applied may experience stuffiness, dampness, and other discomforts, especially in the hot summer months when these discomforts are amplified, adding to the user's annoyance. Furthermore, the liquids absorbed by the absorbent core are mostly organic matter, and the suitable temperature and humidity inside the product provide conditions for microbial growth. The proliferation of microorganisms harmful to human health increases the user's health risks, and the metabolic products of these microorganisms also produce foul odors.

[0004] To address the technical problem of poor breathability of PE films, Chinese utility model patent CN 208989373 U provides a nonwoven fabric base film. This base film comprises a first water-repellent nonwoven fabric and a perforated membrane. The perforated membrane has a first surface with irregularities (concave and convex) and a second surface that is smooth. The first water-repellent nonwoven fabric is combined with the irregular surface of the perforated membrane. The irregular surface of the perforated membrane includes a first region and a second region, with the pore density of the first region being greater than that of the second region. Therefore, this technical solution, on the one hand, uses the first water-repellent nonwoven fabric located on the skin contact side to provide a first layer of leak prevention and filtration for excretory liquids such as urine. On the other hand, the second surface of the perforated membrane is usually still a PE film, which may still result in localized poor breathability in the second region with a lower pore density. On the other hand, the different pore densities of the two regions on the perforated membrane ensure the sealing effect of the core area of ​​the diaper and the breathability of the surrounding areas. However, in practice, the core area of ​​the diaper, namely the second area of ​​the perforated membrane, is under great pressure when the flow rate is high. This may cause body fluid to be squeezed out from the perforated part of the second area or from the holes in the first area, thus affecting the leak-proof effect of the core area of ​​the diaper.

[0005] On the other hand, to facilitate observation of urine volume from the outside, there are two main types of urine indicator methods on the market: one is to coat the PE bottom film layer with ink to display urine, and the other is a urine indicator adhesive. However, the urine indicator adhesive reduces breathability and affects the water-repellent performance of the diaper, i.e., its leak-proof performance. In view of this, Chinese utility model patent CN 217987865 U provides a preferred embodiment, in which the side of the diaper or other product in contact with the ink urine indicator layer is preferably made of a material with liquid absorption and diffusion properties, usually hydrophilic non-woven fabric. However, the leak-proof effect of hydrophilic non-woven fabric is not ideal. The urine indicator adhesive is made of hot melt adhesive and a substance with color-sensitive properties to pH value, and is usually applied to a single layer of water-repellent non-woven fabric, which is only suitable for products with low leak-proof requirements. Furthermore, the hydrophilicity of the urine indicator ink and urine indicator adhesive leads to a reduction in the water-repellent performance of the underlying material in contact with them.

[0006] In view of this, there is a need in the existing technology to balance the breathability and leak-proofness of the bottom layer of the diaper, and to make it suitable for setting the urine display area while balancing the breathability and leak-proofness of the bottom layer. In addition, there is a need to further find alternative technical solutions for PE bottom film to balance the needs of breathability, leak-proofness and urine display of diapers. Utility Model Content

[0007] Therefore, the objective of this invention is to overcome the limitation of prior art in that it cannot simultaneously achieve both breathability and leak-proofness, and to provide a snap-on diaper with superior breathability and leak-proofness through a membrane-free bottom layer with a specific structure. Furthermore, snap-on diapers with this membrane-free bottom layer structure are also suitable for incorporating a wetness indicator.

[0008] In view of this, the present invention provides a snap-on diaper, which has at least a lining layer, an outer cover layer, and an absorbent core located between the lining layer and the outer cover layer, and further includes a core wrapper located between the lining layer and the outer cover layer and surrounding the absorbent core, or located between the lining layer and the outer cover layer and integrated with the absorbent core; a film-free bottom layer located between the absorbent core and the outer cover layer or between the core wrapper and the outer cover layer, and the film-free bottom layer has at least a single substrate without a polyethylene film, the substrate having at least: a first nonwoven layer, which is a spunbond structure located at the bottom of the film-free bottom layer; a second nonwoven layer, which is a meltblown structure disposed on the first nonwoven layer; and a third nonwoven layer, which is a spunbond structure disposed on the second nonwoven layer; wherein, when a polymer layer formed of ethylene-acrylic acid copolymer is formed on the outer surface of the first nonwoven layer, a printed layer is formed on the outer surface of the third nonwoven layer; Alternatively, when a printed layer is constructed on the outer surface of the first nonwoven layer, a polymer layer formed of an ethylene-acrylic acid copolymer is constructed on the outer surface of the third nonwoven layer; wherein, the hydrostatic pressure resistance of the bottomless film layer included in the snap-on diaper is 70~130 mbar.

[0009] In a non-limiting embodiment of the present invention, the breathability of the snap-on diaper can reach 10 to 20 cubic feet per minute per square foot.

[0010] In a non-limiting embodiment of the present invention, the monolithic substrate without a membrane bottom layer is laminated and composited from bottom to top by a first nonwoven layer, a second nonwoven layer and a third nonwoven layer.

[0011] In a non-limiting embodiment of the present invention, the weight ratio of the first nonwoven layer, the second nonwoven layer, and the third nonwoven layer is 20:3:20.

[0012] In a non-limiting embodiment of the present invention, the monolithic substrate without a membrane bottom layer has a urine indicator layer, wherein the urine indicator layer is generally disposed on the back sheet near the crotch area.

[0013] Furthermore, the urine indicator layer is located on the outer surface of the polymer layer, or the urine indicator layer is located in the polymer layer and surrounded by the polymer layer.

[0014] Furthermore, the urine indicator layer is a multi-linear configuration formed by color-changing hot melt adhesive or urine indicator ink.

[0015] In a non-limiting embodiment of the present invention, the film-free substrate includes multiple monolithic substrates.

[0016] Furthermore, the film-free substrate comprises at most three monolithic substrates laminated together, wherein the polymer layer of the lower monolithic substrate is bonded to the printed layer of the upper monolithic substrate.

[0017] Furthermore, in the membrane-free underlayer configuration comprising three monolithic substrates, the urine indicator layer is disposed on the monolithic sheet of the membrane-free underlayer closest to the outer cover layer, or on another monolithic sheet closest to the bottommost monolithic substrate.

[0018] The following description, through specific embodiments and experimental data, illustrates the leak-proof and breathable effects achievable by the snap-on diaper with a membrane-free bottom layer according to this invention. These leak-proof and breathable properties are significantly superior to those of existing polyethylene and polypropylene bottom films. Furthermore, compared to existing bottom films, the snap-on diaper with a membrane-free bottom layer based on this invention is more suitable for installing a wetness indicator due to its excellent leak-proof properties. Attached Figure Description

[0019] Figure 1 A top view of a prior art snap-on diaper in its open, flat state is shown in a line drawing, illustrating the inner surface and basic structure of the diaper on the side facing the body when it is not closed.

[0020] Figure 2An exploded perspective view of a snap-on diaper with a membrane-free bottom layer according to the present invention is shown, wherein the basic structure of the diaper and the arrangement of the membrane-free bottom layer are shown.

[0021] Figure 3 This invention illustrates one construction method of the bottom layer of a snap-on diaper with a membrane-free bottom layer according to the present invention;

[0022] Figure 4 This illustrates another construction method for the bottom layer of a snap-on diaper with a membrane-free bottom layer according to the present invention.

[0023] Reference numerals used repeatedly in this specification and drawings are intended to indicate the same or similar elements of this utility model.

[0024] Figure Labels

[0025] 100-Snap-on Diapers

[0026] 110-Front panel 111-Front waistline edge

[0027] 120 - Back panel 121 - Back waistband edge 122 - Ear loops 122A - Wrap-up piece 122B - Ear loop gripping part 123 - Back waistband side edge 124 - Back waistband elastic band

[0028] T - Horizontal fold line; X - Horizontal Y - Vertical L - Vertical center line

[0029] 130-Crotch area 131-Side edge 132-Core area

[0030] 140 - Lining layer; 150 - Absorbent core; 151 - Leg cuffs

[0031] 160 - Outer Cover Layer; 161 - Front Waist Fastening Belt; 162 - Urine Indicator; 163 - Bottom Film Layer; 164 - Auxiliary Fasteners

[0032] 200-Snap-on Diapers

[0033] 210 - Front panel 220 - Crotch area 230 - Back panel 240 - Lining layer 245 - Flow layer

[0034] 250 - Absorbent core; 255 - Core wrapper; 260 - Spacer layer (optional); 270 - Outer cover layer

[0035] 280 - Non-woven bottom layer; 281 - First nonwoven layer; 282 - Second nonwoven layer; 283 - Third nonwoven layer; 284 - Printed layer; 285 - Polymer layer; 286 - Urine indicator layer Detailed Implementation

[0036] Those skilled in the art will understand that the following detailed description of embodiments is merely an illustration of exemplary models and is not intended to limit the broader aspects of this disclosure.

[0037] Terminology Definition

[0038] Regarding absorbent articles, "disposable" means absorbent articles that are not typically intended to be washed or otherwise restored or reused as absorbent articles (i.e., they are intended to be discarded after a single use and are preferably recyclable, compostable, or in other words, disposed of in an environmentally compatible manner). Disposable absorbent articles typically include an adhesive that is positioned between layers and / or elements to hold the article together (e.g., earpieces, side pieces, and straps are bonded to a base structure via adhesive, and the layers of earpieces, side pieces, straps, and base structure are bonded together using adhesive). Alternatively, thermal bonding and / or ultrasonic bonding may be used in conjunction with or instead of adhesive.

[0039] "Pants" (also known as "training pants," "pre-closed diapers," "diaper pants," "diapers," and "over-the-leg diapers") refers herein to a disposable absorbent article designed for infant wearers and having a continuous perimeter waist opening and continuous perimeter leg openings. Pants may be configured to have a continuous or closed waist opening and two continuous, symmetrically arranged closed leg openings before the article is put on the wearer. Pants may be pre-formed or pre-fastened using various techniques, including but not limited to using any re-fastening closure and / or permanent closure (e.g., seams, thermal bonding, ultrasonic welding, adhesives, glue bonding, mechanical fasteners, etc.) to join the parts of the article together. Pants may be pre-formed at any location around the waist area of ​​the article (e.g., side-fastened or seamed, front waist-fastened or seamed, back waist-fastened or seamed).

[0040] As used in this invention, the term "nonwoven" or "non-woven fabric" generally refers to a web with an interlayered structure of individual fibers or yarns, but not in a manner identifiable as a knitted fabric. Suitable examples of nonwoven or non-woven fabrics or webs include, but are not limited to, meltblown webs, spunbond webs, bonded-carded webs, air-blown webs, co-formed webs, and hydroentangled webs.

[0041] As used herein, the term "spunbond" refers to a process in which molten thermoplastic material is extruded in filament form from multiple, typically circular, fine capillary pores of a spinneret, and then the diameter of the extruded filament is rapidly reduced to form fine fibers using processes such as those described in U.S. Patents US4340563 to Appel et al., US3692618 to Dorschner et al., US3802817 to Matsuki et al., US3338992 and US3341394 to Kinney, US3502538 to Levy, US3502763 to Hartman, and US3542615 to Dobo et al. Spunbond fibers are typically continuous and have a diameter greater than 7 μm (micrometers), specifically, a diameter between approximately 10 and 30 μm. Spunbond fibers are generally non-sticky when placed on a collecting surface.

[0042] As used herein, the term "meltblown" refers to a process in which fibers are produced by extruding molten thermoplastic material in the form of filaments or strands from multiple typically circular die capillaries into a high-speed airflow (e.g., an airflow) that refines the molten thermoplastic material to a diameter reduced to that of microfibers. The meltblown fibers are then carried by the high-speed airflow and deposited onto a collection surface to form a randomly distributed meltblown fiber web. Such a process is disclosed, for example, in Butin's U.S. Patent US3,849,241. Meltblown fibers can be continuous or discontinuous and are typically microfibers with a diameter less than 10 micrometers.

[0043] The term "hot air" as used in this article refers to the following thermal bonding process, which uses bicomponent fibers with a parallel or core-sheath structure. After being carded into a web, the composite fibers are heated with hot air, causing the PE in the composite fibers to melt. The fibers then overlap and, after cooling, become a nonwoven material with certain strength and tensile properties. Because no pressure is applied during processing, hot-air nonwoven materials have far superior elasticity and bulkiness compared to nonwoven materials made by other processes. They are soft and fluffy to the touch, providing a comfortable feel for the user.

[0044] "Proximal" and "distal" refer to the position of an element that is relatively close to or far from the longitudinal or lateral centerline of the structure, respectively (for example, relative to the same longitudinal axis, the proximal edge of a longitudinally extending element is closer to the longitudinal axis than the distal edge of the same element).

[0045] "Facing the body" and "facing the clothing" refer to the relative positions of components or the relative positions of the surfaces of a component or group of components, respectively. "Facing the body" means that during wear, a component or surface is closer to the wearer than some other components or surfaces. "Facing the clothing" means that during wear, a component or surface is further away from the wearer than some other components or surfaces (i.e., the component or surface is closer to the wearer's clothing, which may be worn over a disposable absorbent material).

[0046] As used herein, the terms "stretchable" or "extensible" generally refer to a material that, when stretched or elongated in the direction of force, represents at least about 25%, in some embodiments about 50%, and in some embodiments at least about 75% of its relaxed length or width. Stretchable materials do not necessarily have restorative properties. For example, the material of an elastomer is a stretchable material with restorative properties. Meltblown fiber webs can be stretchable but do not have restorative properties and are therefore stretchable but inelastic materials.

[0047] As used herein, the terms "elastomer" or "elastic" generally refer to a material that, by applying a tensile force, is stretched in at least one direction (e.g., the MD direction), and by releasing the tensile force, shrinks / recovers to approximately its original size. For example, a stretched material may have an elongation at least about 50% longer than its relaxed, unstretched length, and by releasing the tensile force, it may recover to a length within at least 50% of its elongated length. A hypothetical example could be a 1-inch sample of material that can be stretched to 1.50 inches and, by releasing the tensile force, will recover to a length not exceeding 1.25 inches. Ideally, the material shrinks or recovers at least 50%, and even more ideally, at least 80% of the elongated length.

[0048] As used herein, the term "bonding" refers to the joining, adhesion, connection, attachment, etc., of two elements. Two elements are considered to be bonded together when they are joined, adhered, connected, attached, etc., directly or indirectly to each other, such as when bonded to an intermediate element. Bonding can be performed via, for example, adhesives, pressure bonding, thermal bonding, ultrasonic bonding, splicing, stitching, and / or welding.

[0049] As used herein, the term "elastic member" includes elongated materials that are elastic, such as, but not limited to, elastic rubber bands and elastic fiber nonwoven fabrics. Elastic rubber bands, for example, can be made from spandex using a spinning process on a warp beam.

[0050] The term "opening" refers to the initial separation of opposite waist areas before or during the wearing of an article, thus not forming a continuous waist and leg opening.

[0051] The term "closure" refers to the permanent or repeatable secure joining of opposing waist areas during encapsulation to form a continuous waist opening and leg opening.

[0052] snap-on diapers

[0053] First, the basic structure of the snap-on diaper of this embodiment will be explained with reference to the accompanying drawings. Figure 1 A top plan view of a first embodiment of a snap-on diaper known in the prior art is shown in a line drawing, illustrating its side facing the clothing. In this document, in Figure 1 The snap-on diaper 100 shown is a disposable absorbent product designed to be placed against or close to the wearer's body to absorb and contain various excretions from the body. Figure 1 As preferably shown, in the longitudinal Y direction, the snap-on diaper 100 has a front piece 110, a crotch area 130 and a back piece 120 in sequence, wherein the crotch area 130 extends between the front piece 110 and the back piece 120 and connects the front piece 110 and the back piece 120.

[0054] In the thickness direction of the snap-on diaper 100, the diaper 100 is along... Figure 1 The paper-side-inward direction of the diaper may sequentially include a lining layer facing the body, an outer cover layer 160 facing the clothing, and an absorbent core 150 located between the lining layer facing the body and the outer cover layer 160 facing the clothing. Here, the lining layer facing the body, the outer cover layer 160 facing the clothing, and the absorbent core 150 sandwiched between them together define the absorbent assembly of the snap-on diaper 100. The absorbent assembly can be any suitable shape, including, for example, […]. Figure 1 The shape is roughly I-shaped as shown.

[0055] Because this snap-on diaper 100 is a thin product, Figure 1 In the two-dimensional line drawing shown, the front piece 110 refers to the portion of the diaper 100 that is approximately in front of the wearer when the infant or adult user is wearing it. The back piece 120 refers to the portion of the diaper 100 that is approximately behind the wearer when the infant or adult user is wearing it, and the crotch area 130 refers to the portion that is approximately between the wearer's legs when the infant or adult user is wearing it.

[0056] exist Figure 1In the illustrated embodiment, the back piece 120 includes a straight back waist edge 121 and the front piece 110 includes a straight front waist edge 111 and a generally straight back waist side edge 123. Here, a "straight" edge means an edge that is substantially free of curves, bends, angles, notches, or irregular portions. The body-facing lining layer of the snap-on diaper 100 defines a surface facing the wearer's body, which is intended to be worn adjacent to and in direct contact with the wearer's body. The body-facing lining layer is suitably compliant, soft, and non-irritating to the wearer's skin. The body-facing lining layer is less hydrophilic than the absorbent core 150 and its porosity is sufficient to allow liquid permeation. The body-facing lining layer can be made from a variety of suitable web materials, such as porous foam, honeycomb foam, porous plastic film, natural fibers (e.g., wood fibers or cotton fibers), synthetic fibers (e.g., polyester or polypropylene fibers), or a combination of natural and synthetic fibers. The lining layer facing the body is suitably designed to isolate the wearer's skin from the liquids and moisture held by the absorbent core 150.

[0057] exist Figure 1 The diagram also schematically illustrates an outer cover layer 160 of the diaper 100 defining a surface facing the clothing side, intended to be worn adjacent to the wearer's clothing. In a suitable embodiment, the outer cover layer 160 includes a woven or nonwoven fiber web layer that is wholly or partially constructed or treated to impart a desired degree of liquid impermeability to selected areas of the outer cover layer 160 adjacent to or near the absorbent core 150. A bottom film layer 163 is also provided between the outer cover layer 160 and the absorbent core 150, which may include a microporous "breathable" material that allows vapor to escape from the diaper 100 while still preventing liquid leakage. For example, the bottom film layer 163 may be composed of a microporous polymer membrane or nonwoven fabric coated or otherwise treated to impart a desired degree of liquid impermeability. The outer cover layer 160 may also be adjacent to the bottom film layer 163, including an embossed or otherwise patterned layer, to convey visual cues or information to the wearer or caregiver. Preferably, the bottom film layer 163 located between the outer cover layer 160 and the absorbent core 150 can be a thin layer made of a polyethylene resin carrier with an appropriate amount of calcium carbonate added. Here, the visual pattern layer is preferably a pattern that infants and adult users like or a business logo. Preferably, the bottom film layer 163 also has a urine indicator 162 that can convey information about the presence of excrement to caregivers or adult users.

[0058] The body-facing lining layer and the clothing-facing outer cover layer 160 are typically joined to the absorbent core 150 located between them in a face-to-face relationship. The body-facing lining layer and the clothing-facing outer cover layer 160 may be joined to each other around the outer periphery of the diaper 100 in any manner known to those skilled in the art, such as adhesive bonding, ultrasonic bonding, thermal bonding, and combinations thereof.

[0059] As described above, the absorbent core 150 is disposed between the lining layer facing the body and the outer cover layer 160 facing the clothing. The absorbent core 150 is generally conformal and capable of absorbing and retaining liquid bodily waste. The absorbent core 150 may include superabsorbent materials, short fibers, adhesive fibers, and combinations thereof, as known in the art. The absorbent core 150 may have any of a variety of shapes and sizes. For example, a composite absorbent core 150 may be rectangular, I-shaped, or T-shaped. The size and absorbency of the absorbent core 150 should be compatible with the size of the intended wearer and the liquid load imposed by the intended use of the diaper.

[0060] In a suitable embodiment, the diaper 100 may include a flow portion (not shown) disposed between the absorbent core 150 and a lining layer facing the body. The flow portion is used to quickly collect and temporarily retain liquid expelled by the wearer before releasing the liquid back into the absorbent core 150. A variety of woven and nonwoven materials can be used to construct the flow portion. For example, the flow portion may be a spunbond or meltblown web of polyolefin fibers. The flow portion may also be a bonded combed web of natural and synthetic fibers.

[0061] As a preferred aspect, the diaper 100 includes a pair of elastic, longitudinally extending leg cuffs 151. The leg cuffs 151, when worn by an infant, are adapted to fit around the wearer's legs and act as a physical barrier against the lateral flow of bodily waste. In a suitable embodiment, the leg cuffs 151 may be formed from a portion of the outer cover layer 160 and / or a body-facing liner extending beyond the longitudinal side of the absorbent core 150. In another suitable embodiment, the leg cuffs 151 may be formed from a separate material (e.g., stranded leg elastic members) bonded to the outer cover layer 160 and / or the body-facing liner.

[0062] The diaper 100 may also include a front waist elastic member (not shown) and / or a back waist elastic band 124. In the illustrated embodiment, for example, the diaper 100 has a back waist elastic band 124 but not a front waist elastic member. The back waist elastic band 124 is arranged to pull the diaper 100 against the wearer (especially against the wearer's waist) to maintain a fit between the diaper 100 and the wearer's waist, as will be described more fully herein. Preferably, the back waist elastic band 124 may be designed with an attachment area that seals with the back panel 120 and a non-attachment area that does not seal with the back panel 120 and faces the crotch area 130, wherein the non-attachment area may be surrounded by the attachment area to form a back pocket that opens toward the crotch area 130. The back pocket is capable of holding most of the bodily excrement flowing toward the diaper 100, such as, but not limited to, feces excreted by infants.

[0063] Suitable materials for forming leg cuffs 151 and / or back waist elastic bands 124 are known to those skilled in the art. Examples of such materials are strands or strips of polymeric or elastomeric materials that adhere to the diaper 100 in a stretched position or attach to the diaper 100 when the diaper is folded, thereby imparting an elastic contractile force to the diaper. Leg cuffs 151 and / or back waist elastic bands 124 can have any configuration that provides the desired performance. Leg cuffs 151 can be generally straight or optionally curved (e.g., Figure 1 and Figure 4 (as shown), to more closely conform to the wearer's leg contours. As used herein, "elasticity," "elastomer," etc., refers to the ability of a material or composite to stretch by at least about 50% and return to at least 50% of its initial length upon relaxation.

[0064] Leg cuffs 151 and / or back waist elastic bands 124 can be attached to diaper 100 in any manner known to those skilled in the art. For example, leg cuffs 151 and / or back waist elastic bands 124 can be joined to diaper 100 by ultrasonic bonding, thermal bonding, adhesive bonding, and combinations thereof.

[0065] like Figure 1 Clearly visible, the back panel 120 of a diaper typically includes a pair of ear flaps 122. In the prior art, this pair of ear flaps 122 is symmetrically arranged about the longitudinal center line L, and the transverse center line of the ear flaps 122 is generally parallel to the transverse fold line T. The ear flaps 122 are generally located on both sides of the back waist side edge 123 and near the back waist edge 121. In a suitable embodiment according to the prior art, and as... Figure 1As shown, the ear patch 122 can be formed as a separate component and attached to the body-facing liner layer, the outer cover layer 160, or both the body-facing liner layer and the outer cover layer, as is well known in the art. In the illustrated embodiment, the ear patch 122 is attached to the body-facing surface of the body-facing liner layer such that when the diaper 100 is worn, the attached portion of the ear patch 122 is positioned between the wearer's body and the body-facing liner.

[0066] In a suitable embodiment, each of the earplugs 122 includes a wrapping element 122A and an earplug gripping portion 122B attached to the earplug. Figure 1 (As shown). Each of the packages 122A has a proximal edge, a relatively distal edge, a top edge, and a bottom edge. Figure 1 As seen, the proximal edge of each of the wrappers 122A is spaced inwardly from the corresponding back waist side edge 123 of the diaper 100, such that a portion of the wrapper overlaps with the body-facing lining layer. The portion of each of the wrappers 122A that overlaps with the body-facing lining layer is bonded (e.g., adhesive bonding, thermal bonding, thermal bonding, and both adhesive bonding) to at least the body-side lining.

[0067] exist Figure 1 In the prior art shown, the proximal and distal edges of each of the wrappers 122A are generally parallel to each other and both are straight (i.e., linear). Preferably, the length ratio of the distal edge to the proximal edge is suitably about 1:4. Further, the upper and lower edges of each of the wrappers 122A are also configured to be generally parallel to each other and straight, and are generally parallel to the rear waist edge 121 of the rear piece 120.

[0068] Preferably, but not exclusively, each wrapper 122A in the ear loops 122 can be designed as a non-elastic portion, and the ear loop gripping portion 122B can be configured to connect to the wrapper 122A. This allows the size and tightness of the waist opening of the diaper 100 in its wearing configuration to be adjusted according to the wearer's waist circumference by deformation of elements such as the back waist elastic band 124. Figure 1 As shown, the wrapping portion 122A of the ear tabs 122 located on both sides of the back piece 120, which is a non-elastic part, extends laterally outward, and each ear tab gripping portion 122B attached to the non-elastic wrapping portion 122A is configured to engage a ring member provided in the front waist area 161 of the diaper 100 in a wearing configuration, as will be described more fully herein.

[0069] like Figure 1As shown, according to the prior art, the ear patch 122 further includes an ear patch gripping portion 122B extending laterally outward from the wrapper 122A, which is used for manually gripping and manipulating the ear patch. Thus, the back piece 120 (more specifically, the ear patches 122 of the back piece) can be folded and attached to the front piece 110 relative to the lateral fold line T by a pair of ear patch gripping portions 122B symmetrically arranged relative to the longitudinal center line L, defining a three-dimensional wearing configuration with a waist opening and a pair of leg openings, thereby selectively placing the diaper 100 from the front piece 110 as shown in the diagram. Figure 1 The open configuration shown can be moved to a closed or worn configuration.

[0070] Corresponding to the ear loop gripping portion 122B in the rear panel, the diaper 100 also includes a front waist fastening band 161 formed as a separate component and attached to the outer surface of the diaper cover layer 160, see [link to previous section]. Figure 1 More specifically, a band (generally indicated as 161) of fastening material designed as a loop or hook is attached to the front panel 110 of the diaper. This front waist fastening band 161 includes an upper edge, a lower edge, and a pair of side edges connecting the upper and lower edges. The upper edge is spaced apart from the front waist edge 111, and the side edges are spaced apart from the corresponding side edges of the diaper 110. Thus, the ear loop gripping portions 122B provided on the non-elastic portion of the ear loops 122 and the corresponding front waist fastening band 161 are designed to be repeatedly and securely fastened together, thereby securing the diaper 100 in a detachable manner in a wearing configuration.

[0071] The earplug gripping portion 122B and the front waist fastening band 161, which can form a re-fastening engagement with each other, may include any re-fastening fastener suitable for absorbent articles, such as adhesive fasteners, bonding fasteners, mechanical fasteners, etc. In a suitable embodiment, the earplug gripping portion 122B and the front waist fastening band 161 include mechanical fastening components, such as hook and loop fasteners. Figure 1 In the embodiment shown, the earpiece gripper 122B may include a hook-shaped fastener and the front waist fastening strap 161 includes a complementary ring fastener disposed on the outer surface of the outer cover layer 160. Further preferably, as Figure 1 As shown, auxiliary fasteners 164 are added on both sides of the front waist fastening band 161 symmetrically relative to the longitudinal center line L. When the ear-shaped gripping part 122B and the front waist fastening band 161 are fastened together, the auxiliary fasteners 164 are allowed to fasten with the wrapping part 122A designed with hooks or rings to ensure that the diaper 100 has better fit and fastness.

[0072] snap-on diapers with a membrane-free backing

[0073] Figure 2 The snap-on diaper shown in this utility model has the following functions: Figure 1The basic structure of the snap-on diaper 100 shown in the prior art will not be further described here in detail regarding the composition of the front piece 210 located approximately in front of the wearer, the crotch area 220 located approximately between the wearer's crotch and legs, and the back piece 230 located approximately behind the wearer.

[0074] In the thickness direction of the snap-on diaper 200 with a membrane-free bottom layer according to the present invention, the diaper 200 along... Figure 2 The absorbent assembly of the diaper 100, arranged from top to bottom, may sequentially include a liner layer 240 facing the body, an outer cover layer 270 facing the clothing, and an absorbent core 250 located between the liner layer 240 facing the body and the outer cover layer 240 facing the clothing. Here, the liner layer 240 facing the body, the outer cover layer 270 facing the clothing, and the absorbent core 250 sandwiched between them together define the absorbent assembly of the diaper 100. The absorbent assembly can be any suitable shape, including, for example, […]. Figure 2 The shape is roughly I-shaped as shown.

[0075] In one embodiment of the present invention, the diaper 200 further includes an additional component called a flow layer 245, which, like the core wrapper 255 and optional spacer layer 260, facilitates fluid management within the diaper 200. The flow layer 245 is typically located between the liner layer 240 and the absorbent core 250. Alternatively, if the core wrapper 255 is present, it is located between the liner layer 240 and the core wrapper 255. The flow layer 245 helps to mitigate and diffuse the flow or burst of liquid bodily fluids penetrating the liner layer 240, and achieves this by absorbing and distributing bodily fluids for absorption by the absorbent core 250. Figure 2 As shown, the flow layer 245 is located below the male and female fluid flow locations of the liner 240, and the approximate size of the flow layer 245 is smaller than that of the liner 240 and approximately the same width as the absorbent core 250. The length of the flow layer 245 is typically shorter than that of the absorbent core 250. The flow layer 245 may contact and / or bond to the liner 240. Bonding of the flow layer 245 to the liner 240 can be achieved using adhesives and / or point fusion bonding. Point fusion bonding can be selected from ultrasonic bonding, pressure bonding, thermal bonding, and combinations thereof.

[0076] The flow layer 245 may include natural fibers, synthetic fibers, superabsorbent materials, woven materials, nonwoven materials, wet-spun fiber webs, substantially unbonded air-spun fiber webs, operably bonded stabilized air-spun fiber webs, and combinations thereof. In a particular embodiment, the flow layer 245 may be formed of a substantially hydrophobic material, such as a nonwoven web composed of polypropylene, polyethylene, polyester, and combinations thereof. The flow layer 245 may also be formed of one or more materials selected from meltblown-spunbond-meltblown fabrics, spunbond fabrics, meltblown fabrics, co-formed fabrics, carded webs, bonded carded webs, bicomponent spunbond fabrics, spunlace fabrics, tissue paper, and combinations thereof.

[0077] The core wrapper 255 can be bonded to the absorbent core 250. The bonding of the core wrapper 255 to the absorbent core 250 can be achieved by, but is not limited to, adhesives. The core wrapper 255 can be constructed from a single sheet of material that can partially or completely surround the absorbent core 250 and can be sealed together using sealing means such as ultrasonic bonding or other thermochemical bonding means or the use of adhesives. The core wrapper 255 can include, but is not limited to, natural and synthetic fibers such as polyester, polypropylene, acetate, nylon, polymeric materials, cellulose materials, and combinations thereof. Natural fibers can include wool, cotton, flax, hemp, and wood pulp. The material forming the core wrapper 255 can be selected from meltblown-spunbond-meltblown fabrics, spunbond fabrics, meltblown fabrics, co-formed fabrics, carded webs, bonded carded webs, bicomponent spunbond fabrics, spunlace fabrics, tissue paper, and combinations thereof. Furthermore, the core wrapper 255 can be made from spunbond-meltblown-spunbond (“SMS”) materials (e.g., 10 gsm spunbond-meltblown-spunbond material). Furthermore, the core wrapper 255 may be less hydrophilic than the absorbent core 250, but porous enough to allow liquid body effluents to pass through the core wrapper 255 to reach the absorbent core 250.

[0078] Optionally, the diaper 200 according to this invention may also be configured with a spacer layer 260. The spacer layer 260 is typically located between the absorbent core 250 and the outer cover layer 270. The purpose of the spacer layer 260 is to prevent moisture from migrating outward from the absorbent core 250 and through the outer cover layer 270. When this type of moisture migration occurs, the outer cover layer 270 may feel damp, which can be considered product leakage. The dimensions of the spacer layer 260 match the dimensions of the absorbent core 250 and are typically smaller than the dimensions of the outer cover layer 270. The outer cover layer 270 is typically breathable, allowing water vapor (but not liquid) to pass through; and the dimensions of the spacer layer 260 typically do not interfere with this function of the outer cover layer 270. The spacer layer may be made of known nonwoven materials, which may include spunbond-meltblown-spunbond materials.

[0079] Next, combined Figure 2 , Figure 3 and Figure 4 The specific structure of the membrane-free backing 280 according to this utility model will be described below. The membrane-free backing 280 can be composed of a single nonwoven material, or it can be composed of two or three layers of nonwoven material in an upper and lower conformal manner. See also... Figure 3 The nonwoven substrate 280 is laminated from at least a first nonwoven layer 281, a second nonwoven layer 282, and a third nonwoven layer 283. Specifically, the first nonwoven layer 281 is made of thermoplastic polymer particles, typically polypropylene (PE), wherein the thermoplastic polymer particles are melted and extruded through the spinneret orifice of a spunbond die to form continuous filaments. These filaments are placed on a conveyor belt to form a web structure, thus constructing the first nonwoven layer 281 of the nonwoven substrate 280, which has higher strength compared to other nonwoven material products. Therefore, the first nonwoven layer provides the basic strength and stability of the nonwoven substrate 280.

[0080] Furthermore, the second nonwoven layer 282 is formed by extruding molten thermoplastic polymer particles, typically molten polypropylene particles, through the spinnerets of a smaller meltblown die to form microfibers. Specifically, the spinnerets of the meltblown die can be a row of capillary nozzles spaced less than 1 mm apart and with a diameter of 0.2–0.4 mm. These microfibers are blown by hot air from vents near the spinnerets of the meltblown die and further drawn and elongated into fibers with a diameter generally in the range of 1–10 μm to form a microfiber web. As the hot air flows downwards, it mixes with the surrounding air, causing the microfibers and the microfiber web to cool and eventually solidify into short, fine fibers onto a moving conveyor belt, thereby forming a finer network configuration than the first nonwoven layer 281. Therefore, the second nonwoven layer 282 provides superior filtration, barrier, and absorption properties compared to the first nonwoven layer 281.

[0081] Furthermore, the third nonwoven layer 283 is formed by extruding molten thermoplastic polymer particles through the spinneret of a spunbond die to form continuous filaments, in the same manner as the first nonwoven layer 281, and is further laid on a conveyor belt. The first nonwoven layer 281, the second nonwoven layer 282, and the third nonwoven layer 283 can also be individually manufactured on different production lines and then combined by a hot rolling process, or the first nonwoven layer 281 and the second nonwoven layer 282 can be formed on the same production line and then hot-rolled with the separately manufactured third nonwoven layer 283. In a preferred embodiment of the present invention, the first nonwoven layer 281, the second nonwoven layer 282, and the third nonwoven layer 283 are sequentially processed on the same production line and stacked on the same conveyor belt, and then combined by hot rolling, thereby constructing a denser and stronger substrate for a nonwoven underlayer 280 suitable for sanitary products.

[0082] In a non-limiting embodiment of the present invention, the basis weight ratio of the first nonwoven layer 281 and the second nonwoven layer 282 is 20:3, and the basis weight ratio of the second nonwoven layer 282 to the third nonwoven layer 283 is 3:20. In other words, the first nonwoven layer 281 and the third nonwoven layer 283 according to the present invention are configured to have the same basis weight ratio, such that the top and bottom surfaces of the substrate of the membrane-free underlayer 280 have better strength relative to the second nonwoven layer 282 located in the middle of the substrate of the membrane-free underlayer 280, and the second nonwoven layer 282 located in the middle of the substrate of the membrane-free underlayer 280 provides superior filtration, barrier, and absorption properties compared to the second nonwoven layer 282 and the third nonwoven layer 283, with the aim of effectively absorbing a large amount of fluid in the middle of the substrate of the membrane-free underlayer 280.

[0083] In a non-limiting embodiment of the present invention, after the substrate of the non-film-free underlayer 280 is hot-rolled from a first nonwoven layer 281, a second nonwoven layer 282, and a third nonwoven layer 283, a printed layer 284 can be formed on the side of the non-film-free underlayer 280 facing the outer cover layer 270. Furthermore, a 2D or 3D pattern can be formed on the surface of the first nonwoven layer 281 having the printed layer 284 or the third nonwoven layer 283 having the printed layer 284 by means of a 2D or 3D embossing device having at least a first embossing roller and a second embossing roller.

[0084] The following description uses only the first nonwoven layer 281 as an example to describe the printed layer thereon. This arrangement of multiple 2D or 3D raised features gives the surface of the first nonwoven layer 281 of the membrane-free bottom layer 280 a textured surface, thereby reducing the contact area between the diaper 200 according to this invention and the skin of infants or adult users, thus further increasing the breathability of the membrane-free bottom layer 280. Furthermore, those skilled in the art can also design the surface raised features of the printed layer 284 according to the preferences of wearers of different genders and ages to attract users and prevent the diaper 200 from being overly conspicuous after being soiled by bodily fluids.

[0085] In a non-limiting embodiment of the present invention, after the printing layer 284 of the film-free underlayer 280 is formed, a polymer coating can be formed on the surface of a first nonwoven layer 281 or a third nonwoven layer 283 away from the printing layer 284 of the film-free underlayer 280. This document describes the polymer coating on the third nonwoven layer 283 as an example. Unlike the PE polyethylene plastic film in the prior art, the present invention uses Ethylene Acrylic Acid Copolymers (EAA) to construct an ethylene-acrylic acid copolymer layer on the third nonwoven layer 283. Specifically, the ethylene-acrylic acid copolymer is applied into a coating bath, and through the co-directional or counter-directional rotational movement of the gravure roller, the material roller, and the back pressure roller partially immersed in the coating bath, the third nonwoven layer 283 of the film-free underlayer 280 contacts the ethylene-acrylic acid copolymer on the surface of the gravure roller, thereby constructing an ethylene-acrylic acid copolymer layer on the surface of the third nonwoven layer 283.

[0086] Alternatively, a denser first ethylene-acrylic copolymer layer can be formed on the surface of the third nonwoven layer 283 using microgravure coating technology, solely through the counter-rotation of a gravure roller and a material roller immersed in a coating bath, and a doctor blade in direct contact with the gravure roller. The coating thickness can be set to a range of 2 μm to 200 μm as needed. Furthermore, a second ethylene-acrylic copolymer layer can be constructed on top of the first ethylene-acrylic copolymer layer in the same manner. Therefore, a sheet material combining a single or double ethylene-acrylic copolymer layer and a 3D convex, film-free underlayer 280 has been provided for the diaper 200 according to this invention.

[0087] The technical advantages of the ethylene-acrylic acid copolymer layer applied to the membrane-free substrate 280 provided by this utility model are as follows: On the one hand, compared with polyethylene (PE) and polypropylene (PP), the carboxyl groups (-COOH) distributed in the molecular structure of the ethylene-acrylic acid copolymer of this copolymer layer can give it stronger adhesion, thereby enhancing the leak-proof performance of the membrane-free substrate 280; on the other hand, the ethylene-acrylic acid copolymer emulsion coated on the substrate can replace traditional materials such as PE film for waterproofing and seepage prevention. This copolymer layer is harmless and non-toxic to the human body, can decompose rapidly in the natural environment, and has good mechanical stability and aging resistance.

[0088] In a non-limiting embodiment of the present invention, a urine indicator layer 286 may be further provided on the ethylene-acrylic acid copolymer layer of the aforementioned pre-formed film-free underlayer 280. The urine indicator layer 286 may be a multi-linear configuration formed by color-changing hot melt adhesive or urine indicator ink. The urine indicator layer 286 may be directly provided on the first or second ethylene-acrylic acid copolymer layer of the film-free underlayer 280 sheet by flexographic printing or photogravure printing. The film-free underlayer 280 is generally located on the back sheet 230 near the crotch area 220 after cutting. Alternatively, the color-changing ink or color-changing adhesive used for the urine indicator layer 286 may be directly applied to the center of a planar gravure plate, and ethylene-acrylic acid copolymer may be arranged around it, so that the color-changing ink or color-changing adhesive and the surrounding ethylene-acrylic acid copolymer are directly formed on the surface of the third nonwoven layer 283 of the film-free underlayer 280 by gravure printing. Therefore, the membrane-free bottom layer 280, while ensuring leak-proof performance, can also indicate the fullness of the diaper 200 by changing its color when the diaper is filled with body fluid.

[0089] On the other hand, see Figure 4 As shown, the membrane-free underlayer composite 290 according to this invention can also be laminated from two or three membrane-free underlayer 280 sheets. The urine indicator layer 286 can be disposed on a single sheet of the membrane-free underlayer 280 closest to the outer cover layer 270, or the urine indicator layer 286 can be disposed on another single substrate closest to the bottommost single substrate, while the urine indicator layer 286 is not required on the topmost membrane-free underlayer 280 sheet. In the case where the membrane-free underlayer 280 comprises three laminated single substrates, the polymer layer 285 of the bottom single substrate is bonded to the printed layer 284 of the top single substrate.

[0090] This membrane-free bottom layer composite 290, which is made of multiple membrane-free bottom layer 280 sheets laminated together, has superior seepage prevention properties while maintaining breathability.

[0091] However, it is well known that the urine indicator layer, whether made of urine indicator adhesive or urine indicator ink, is generally composed of hydrophilic substances. Therefore, in the existing technology, placing the urine indicator layer in the bottom layer of the diaper will reduce the hydrostatic pressure resistance of the surrounding fabric or non-woven material, which means it will reduce the leakage resistance of the non-woven membrane bottom layer 280.

[0092] Therefore, the hydrostatic pressure resistance and leak-proof performance of the membrane-free bottom sheet according to the present invention, in the case of having both an ethylene-acrylic acid copolymer layer and a urine indicator layer, will be further demonstrated below by hydrostatic pressure resistance test.

[0093] hydrostatic pressure resistance test

[0094] In this test, the sample can be a fully assembled snap-on diaper 200 with a membrane-free bottom layer 280.

[0095] Optionally, the hydrostatic pressure resistance of a single 280-sheet membrane-free substrate can be tested under low hydrostatic pressure using a HYDROTESTER III FX 3000 hydrostatic pressure tester provided by Textest. The tester has a built-in water tank that generates the test pressure, and the tank is connected to the test probe. The 280-sheet membrane-free substrate sample can be mounted on the test stage simply by controlling the control lever. During the test, test water permeates the sample from three different locations. No human supervision is required throughout the test; the tester directly displays the digital test results. The sample's hydrostatic pressure resistance test results can reach 70~130 mbar, meaning it can withstand a maximum pressure of 70~130 mbar per unit area without leakage.

[0096] According to the invention patent application CN 115071230A filed by Taiwan Plastics Industry Co., Ltd., commercially available diaper bottom films have a hydrostatic resistance greater than 400 mmH2O (millimeters of water column) [commercially available diaper bottom films (polyethylene film) PE18, produced by Zhuhai Aixin Technology, have a hydrostatic resistance less than 400 mmH2O and are not suitable as bottom films for hygiene products]. After conversion, the hydrostatic resistance value of this PE-18 film is 39 mbar. The polypropylene composite film prepared by Taiwan Plastics Industry Co., Ltd. can have a maximum hydrostatic resistance value between 400 mmH2O and 1200 mmH2O, which translates to a hydrostatic resistance value of 39 mbar to 117.67 mbar. This hydrostatic resistance value is still lower than the hydrostatic resistance value of the 280 sheet material without a film bottom layer provided by this invention.

[0097] In summary, the membrane-free bottom sheet for diapers claimed by this utility model has demonstrated significantly superior hydrostatic pressure resistance compared to the prior art polyethylene film bottom layer and polypropylene composite film through its ethylene-acrylic acid copolymer layer. In other words, even with an ink urine indicator on a single membrane-free bottom sheet 280, the sheet still has a superior leak-proof effect compared to polyethylene and polypropylene bottom films.

[0098] Breathability test

[0099] In this test, the sample can be a fully assembled snap-on diaper 200 with a membrane-free bottom layer 280.

[0100] Optionally, the FX 3300 LabAir series air permeability analyzer from Textest can be used. This instrument uses a suction pump with a built-in silencer to extract air through a detachable test head with a circular opening. During operation, the test probe is first installed on the air permeability analyzer. After the operator identifies the three test sites on the sample, the clamping handle is pressed down, the test head is opened, and the sample is clamped onto the test head. The suction pump starts automatically. The pre-selected test pressure is automatically set and remains constant. After a few seconds, the instrument measures the airflow through a variable orifice. The air permeability of the test sample is measured from the pressure drop through this orifice and displayed directly in the selected unit of measurement.

[0101] The actual test shows the volume of gas permeating the diaper per minute per unit area (ft³ / ft² / min, the cubic feet of gas per minute per square foot of the diaper). A higher value indicates more gas permeates the product, and better breathability. Tests showed that the breathability of the snap-on diaper 200 with a membrane-free bottom layer 280 reached 10-20 ft³ / ft² / min, while under the same testing conditions, the breathability of ordinary bottom-film products was <1 ft³ / ft² / min.

[0102] In summary, the membrane-free bottom sheet for diapers claimed in this utility model has excellent leak-proof performance as well as excellent breathability.

[0103] The embodiments of this utility model have been illustrated and described herein, but those skilled in the art should understand that various modifications, omissions, and additions can be made without departing from the spirit and scope of this utility model. It should not be understood as limited to the specific embodiments described herein, but encompasses all possible embodiments embodied within the scope and equivalents of the features described in the appended claims.

[0104] The dimensions and values ​​disclosed herein should not be construed as strictly limited to the precise numerical values ​​stated. Rather, unless otherwise specified, each such dimension is intended to represent the value and a functionally equivalent range around that value. For example, a dimension disclosed as “40 mm” is intended to represent “approximately 40 mm”.

[0105] All documents referenced in the “Detailed Description” section are incorporated herein by reference in the relevant sections; no reference to any document should be construed as an admission that it is prior art concerning this utility model. In the event of any conflict between the meaning or definition of any term in this written document and the meaning or definition of any term in the referenced documents, the meaning or definition assigned to the term in this written document shall prevail.

[0106] While specific embodiments of the present invention have been shown and described, it will be apparent to those skilled in the art that many other changes and modifications can be made without departing from the spirit and scope of the present invention. Therefore, the appended claims are intended to cover all such changes and modifications within the scope of the present invention.

[0107] When describing elements of the present invention or their preferred embodiments(s), the articles “a,” “an,” “the,” and “the” are intended to indicate the presence of one or more elements. The terms “comprising,” “including,” and “having” are intended to be inclusive and mean that additional elements may be present in addition to the listed elements. Many modifications and variations may be made to the present invention without departing from the spirit and scope thereof. Therefore, the above embodiments are not intended to limit the scope of the present invention.

Claims

1. A snap-on diaper (200) comprising at least a lining layer (240), an outer cover layer (270), and an absorbent core (250) located between the lining layer (240) and the outer cover layer (270), characterized in that, It also includes, A core wrapper (255) is located between the liner layer (240) and the outer cover layer (270) and surrounds the absorbent core (250), or is located between the liner layer (240) and the outer cover layer (270) and is integrated with the absorbent core (250). A membrane-free underlayer (280) is located between the absorbent core (250) and the outer cover layer (270) or between the core wrapper (255) and the outer cover layer (270), and the membrane-free underlayer (280) has at least a single substrate without a polyethylene film, the substrate having at least: The first nonwoven layer (281) is a spunbond structure located at the bottom of the membrane-free bottom layer (280); The second nonwoven layer (282) is a meltblown structure disposed on the first nonwoven layer (281); The third nonwoven layer (283) is a spunbond structure disposed on the second nonwoven layer (282); Wherein, when a polymer layer (285) formed of an ethylene-acrylic acid copolymer is formed on the outer surface of the first nonwoven layer (281), a printed layer (284) is formed on the outer surface of the third nonwoven layer (283); or When a printed layer (284) is formed on the outer surface of the first nonwoven layer (281), a polymer layer (285) formed of ethylene-acrylic acid copolymer is formed on the outer surface of the third nonwoven layer (283). The snap-on diaper (200) includes a membrane-free bottom layer (280) with a hydrostatic pressure resistance of 70-130 millibars.

2. The snap-on diaper (200) according to claim 1, characterized in that, The snap-on diaper (200) has a breathability of 10-20 cubic feet per minute per square foot.

3. The snap-on diaper (200) according to claim 1, characterized in that, The monolithic substrate of the membrane-free bottom layer (280) is laminated and composited from bottom to top by a first nonwoven layer (281), a second nonwoven layer (282) and a third nonwoven layer (283).

4. The snap-on diaper (200) according to claim 3, characterized in that, The weight ratio of the first nonwoven layer (281), the second nonwoven layer (282), and the third nonwoven layer (283) is 20:3:

20.

5. The snap-on diaper (200) according to claim 2, characterized in that, The monolithic substrate of the membrane-free bottom layer (280) has a urine indicator layer (286), wherein the urine indicator layer (286) is generally disposed on the back sheet (230) near the crotch area (220).

6. The snap-on diaper (200) according to claim 5, characterized in that, The urine indicator layer (286) is located on the outer surface of the polymer layer (285), or the urine indicator layer (286) is located in the polymer layer (285) and surrounded by the polymer layer (285).

7. The snap-on diaper (200) according to claim 6, characterized in that, The urine indicator layer (286) is a multi-linear configuration formed by color-changing hot melt adhesive or urine indicator ink.

8. The snap-on diaper (200) according to claim 2, characterized in that, The membrane-free substrate (280) comprises multiple monolithic substrates.

9. The snap-on diaper (200) according to claim 8, characterized in that, The film-free substrate (280) comprises up to three monolithic substrates laminated together, wherein a polymer layer (285) of the lower monolithic substrate is bonded to a printed layer (284) of the upper monolithic substrate.

10. The snap-on diaper (200) according to claim 9, characterized in that, In a membraneless underlayer (280) configuration comprising three monolithic substrates, the urine indicator layer (286) is disposed on the monolithic sheet of the membraneless underlayer (280) closest to the outer cover layer (270), or on another monolithic sheet closest to the bottommost monolithic substrate.

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