Absorbent article

Abstract

Provided is an absorbent article which can easily keep the skin side dry even when a large amount of bodily fluid is discharged at a time, and which can suppress discomfort when worn due to a large thickness of the absorbent body. This absorbent article is provided with: a top sheet that comes into contact with the skin of a wearer in the front-rear direction, the width direction, and the thickness direction that are orthogonal to each other; and an absorbent body that is disposed further toward the non-skin side than the top sheet and that has an absorbent material that absorbs bodily fluids. The absorbent body has an upper absorbent layer and a lower absorbent layer disposed closer to the non-skin side than the upper absorbent layer. The absorbent material of the upper-side absorbent layer and the absorbent material of the lower-side absorbent layer contain fibers and a highly absorbent polymer. The density of the lower absorption layer is higher than that of the upper absorption layer. The weight ratio of the superabsorbent polymer to the weight of the entire absorbent material in the upper absorbent layer is 50% or more. The weight ratio of the superabsorbent polymer in the lower absorbent layer relative to the total weight of the absorbent material is 50% or more.

Description

Technical Field

[0001] This utility model relates to an absorbent article having an upper absorbent layer and a lower absorbent layer. Background Technology

[0002] Patent Document 1 discloses an absorbent comprising fibers (fluff pulp) and a highly absorbent polymer. The absorbent has an upper absorbent layer and a lower absorbent layer. The upper absorbent layer comprises fibers and is relatively thick.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-030100 Utility Model Content

[0006] Problems to be solved by utility models

[0007] Patent Document 1 has an upper absorbent layer with fibers and a relatively thick thickness. Therefore, when a large amount of bodily fluid is expelled at once, it cannot be completely absorbed, making it difficult to keep the skin-friendly side of the absorbent item dry. Furthermore, the thickness of the absorbent layer due to the presence of fibers can easily cause discomfort when wearing it.

[0008] This invention was made in view of the following problem: it provides an absorbent article that can easily keep the skin side of the absorbent article dry even when a large amount of bodily fluid is expelled at once, and can suppress discomfort when wearing it caused by the thickness of the absorbent body.

[0009] Solution for solving the problem

[0010] An absorbent article comprises: a front-to-back direction, a width direction, and a thickness direction, which are orthogonal to each other; a top sheet that contacts the wearer's skin; and an absorbent body disposed at a position closer to the non-skin side than the top sheet, having an absorbent material for absorbing bodily fluids. The absorbent body has an upper absorbent layer and a lower absorbent layer disposed at a position closer to the non-skin side than the upper absorbent layer. The absorbent material of the upper absorbent layer and the absorbent material of the lower absorbent layer comprise fibers and a highly absorbent polymer. The density of the lower absorbent layer is higher than that of the upper absorbent layer. The weight ratio of the highly absorbent polymer in the upper absorbent layer relative to the total weight of the absorbent material is 50% or more. The weight ratio of the highly absorbent polymer in the lower absorbent layer relative to the total weight of the absorbent material is 50% or more.

[0011] Preferably, the upper absorbent layer has a plurality of sheets and a highly absorbent polymer disposed between the sheets, wherein the highly absorbent polymer is bonded to the sheets not by an adhesive, but by welding the plurality of sheets together.

[0012] Preferably, the lower absorbent layer is not bonded using an adhesive, but rather cured by the intertwining of fibers.

[0013] Preferably, the thickness of the upper absorption layer is greater than the thickness of the lower absorption layer.

[0014] Preferably, the bending stiffness of the lower absorption layer is higher than that of the upper absorption layer.

[0015] Preferably, the tensile strength of the upper absorbent layer when wet is higher than that of the lower absorbent layer when wet.

[0016] Preferably, the absorbent has an intermediate absorbent layer disposed between the upper absorbent layer and the lower absorbent layer, the intermediate absorbent layer having an opening disposed centrally in the width direction and extending through in the thickness direction across the crotch region of the absorbent article.

[0017] Preferably, the upper absorbent layer and the lower absorbent layer are joined within the opening.

[0018] Preferably, the absorbent article has a compression portion formed by compressing the upper absorbent layer and the lower absorbent layer along the thickness direction.

[0019] Preferably, the lower absorbent layer is an absorbent manufactured by a wet web forming process, i.e., a wet method.

[0020] Preferably, the absorbent article has a non-skin side sheet that abuts against the non-skin side of the lower absorbent layer, the non-skin side sheet having higher liquid diffusivity than the lower absorbent layer.

[0021] Preferably, the thickness of the lower absorbent layer after fluid absorption is less than 150% of the thickness before fluid absorption.

[0022] Preferably, the thickness of the absorbent after absorption is less than 300% of its thickness before absorption.

[0023] Preferably, the permeability of the highly absorbent polymer in the upper absorbent layer is higher than that of the highly absorbent polymer in the lower absorbent layer.

[0024] Preferably, the average inter-fiber distance of the lower absorbent layer is shorter than the average inter-fiber distance of the upper absorbent layer.

[0025] Preferably, the thickness of the upper absorption layer is less than 3 mm, the thickness of the lower absorption layer is less than 2.5 mm, and the overall thickness of the absorber is less than 6.5 mm. Attached Figure Description

[0026] Figure 1 This is a top view of the absorbent article of Embodiment 1, viewed from the skin side.

[0027] Figure 2 This is a top view of the absorbent article of Embodiment 1, viewed from the non-skin side.

[0028] Figure 3 It is along Figure 1 The cross-sectional view shown along line AA.

[0029] Figure 4 This is a top view of the intermediate absorption layer.

[0030] Figure 5 This is a top view of the intermediate absorption layer in the modified example.

[0031] Explanation of reference numerals in the attached figures

[0032] 1. Absorbent material; 10. Top sheet; 30. Absorbent body; 31. Upper absorbent layer; 32. Lower absorbent layer; 33. Middle absorbent layer; 34. Opening; 80. Compression section; R1. First region; R2. Second region; R10. Outer region; L. Front-back direction; S1. Crotch region; S2. Front region; S3. Back region; T. Thickness direction; T1. Skin side; T2. Non-skin side; W. Width direction. Detailed Implementation

[0033] (1) Overview of the implementation method

[0034] Based on the description in this specification and the accompanying drawings, at least the following matters become clear.

[0035] The utility model of Method 1 is an absorbent article comprising: a front-to-back direction, a width direction, and a thickness direction, which are orthogonal to each other; a top sheet that abuts against the wearer's skin; and an absorbent body disposed at a position closer to the non-skin side than the top sheet, having an absorbent material for absorbing bodily fluids. The absorbent body has an upper absorbent layer and a lower absorbent layer disposed at a position closer to the non-skin side than the upper absorbent layer. According to this method, since both the upper and lower absorbent layers are composed of highly absorbent polymers with a high weight ratio, the retention performance of bodily fluids such as urine is high. Even when a large amount of bodily fluid is expelled at once, it is easy to retain bodily fluids and keep the skin-side surface of the absorbent article dry. Since both the upper and lower absorbent layers are composed of absorbent materials with a low weight ratio of fibers, it is easy to make the absorbent body thinner. This can suppress discomfort caused by a thicker absorbent body during wear. The lower absorbent layer has a higher density and fewer gaps between fibers, thus suppressing excessive expansion of the highly absorbent polymer and controlling the thickness of the absorbent body during swelling. Therefore, it is possible to suppress changes in the thickness of the lower absorbent layer and ensure that the bonding state with respect to the garment is maintained relative to the garment's adhesive surface.

[0036] According to a preferred embodiment, the utility model of embodiment 2, based on the utility model of embodiment 1, can have the following features: The upper absorbent layer has multiple sheets and a highly absorbent polymer disposed between the sheets. The highly absorbent polymer is not bonded to the sheets using an adhesive, but rather by welding the multiple sheets together. According to this embodiment, since the highly absorbent polymer is bonded by welding instead of using an adhesive, compared to a structure where the upper absorbent layer has an adhesive, the resistance of the adhesive to body fluids can be suppressed, and the diffusion of body fluids within the upper absorbent layer and the transfer of body fluids to the lower absorbent layer can be improved. Furthermore, compared to a structure where the upper absorbent layer has an adhesive, the fibers do not solidify due to the adhesive, and the highly absorbent polymer can easily move within the absorbent body. The absorbed highly absorbent polymer can move in the planar direction, easily deforming and conforming to the body's contours.

[0037] According to a preferred embodiment, the utility model of embodiment 3, based on the utility models of embodiment 1 or 2, may have the following features: The lower absorbent layer is not bonded using an adhesive, but rather cured by the intertwining of fibers. Compared to a structure where the lower absorbent layer has an adhesive, the fibers do not cure due to the adhesive, and the highly absorbent polymer can easily move within the lower absorbent layer. The absorbed highly absorbent polymer can move in the planar direction, easily deforming and conforming to the body's lines.

[0038] According to the preferred embodiment, the utility model of embodiment 4, based on any of the utility models of embodiments 1 to 3, may have the following features: The thickness of the upper absorbent layer is greater than the thickness of the lower absorbent layer. According to this embodiment, since the upper absorbent layer is relatively thick, it has higher cushioning properties and retains thickness even after absorption. Therefore, it easily maintains its shape even when subjected to external forces such as body movements, reducing discomfort relative to the body. Furthermore, since the lower absorbent layer is relatively thin, it easily follows the deformation of the upper absorbent layer while maintaining the overall thinness of the absorbent body, reducing discomfort during wear and after absorption.

[0039] According to a preferred embodiment, the utility model of embodiment 5, based on any of embodiments 1 to 4, may have the following features: The bending stiffness of the lower absorbent layer is higher than that of the upper absorbent layer. According to this embodiment, since the bending stiffness of the upper absorbent layer is relatively low, discomfort relative to the body can be reduced; furthermore, the upper absorbent layer easily conforms to the body's contours. Since the bending stiffness of the lower absorbent layer is relatively high, it is easy to maintain a flat shape on the non-skin side of the absorbent material, making it easy to install on clothing such as underwear, and also easy to maintain a connection with the clothing.

[0040] According to a preferred embodiment, the utility model of embodiment 6, based on any of embodiments 1 to 5, may have the following features: The tensile strength of the upper absorbent layer when wet is higher than that of the lower absorbent layer when wet. According to this embodiment, the higher tensile strength of the upper absorbent layer when wet helps to suppress deformation during use. Even with prolonged use or absorption of large amounts of bodily fluids, deformation of the upper absorbent layer located on the skin side can be suppressed, thus continuously reducing discomfort during wear.

[0041] According to a preferred embodiment, the utility model of embodiment 7, based on any of embodiments 1 to 6, may have the following features: The absorbent body has an intermediate absorbent layer disposed between the upper absorbent layer and the lower absorbent layer. The intermediate absorbent layer forms an opening extending through the thickness direction, disposed at the center in the width direction across the crotch area of ​​the absorbent article. The center in the width direction of the crotch area of ​​the absorbent article is a region that is easily disposed opposite to an excretory opening and easily guides bodily fluids. According to this embodiment, the transfer of bodily fluids from the upper absorbent layer to the lower absorbent layer can be facilitated by means of the opening in the intermediate absorbent layer.

[0042] According to a preferred embodiment, the utility model of embodiment 8, based on the utility model of embodiment 7, can have the following features: The upper absorbent layer and the lower absorbent layer are joined within the opening. According to this embodiment, positional misalignment of the upper and lower absorbent layers can be suppressed, and the overall thickness of the absorbent body can be reduced, thus reducing discomfort during wear. Furthermore, since the upper and lower absorbent layers are tightly sealed within the opening, the transfer of bodily fluids from the upper absorbent layer to the lower absorbent layer can be facilitated.

[0043] According to a preferred embodiment, the utility model of embodiment 9, based on any of embodiments 1 to 8, may have the following features: The absorbent article has a compression portion formed by compressing the upper absorbent layer and the lower absorbent layer along the thickness direction. According to this embodiment, the upper absorbent layer and the lower absorbent layer can be joined by the compression portion, which can suppress positional displacement of the upper and lower absorbent layers, and can suppress the overall thickness of the absorbent body and reduce discomfort during wear. Furthermore, since the upper absorbent layer and the lower absorbent layer are joined by the compression portion, the transfer of bodily fluids from the upper absorbent layer to the lower absorbent layer can be promoted.

[0044] According to a preferred embodiment, the utility model of embodiment 10, based on any of the utility models of embodiments 1 to 9, may have the following features: The lower absorbent layer is an absorbent body manufactured by wet web forming (wet process). Because the absorbent body is manufactured by wet web forming, there are fewer gaps between the fibers, which can suppress the expansion of the highly absorbent polymer and prevent the absorbent body from becoming too thick.

[0045] According to a preferred embodiment, the utility model of embodiment 11, based on the utility model of embodiment 10, may have the following features: It has a non-skin side sheet that abuts against the non-skin side of the lower absorbent layer. The liquid diffusivity of the non-skin side sheet is higher than that of the lower absorbent layer. According to this embodiment, it is possible to promote the transfer of body fluid from the lower absorbent layer to the non-skin side sheet, to inhibit the continuous accumulation of body fluid in the lower absorbent layer produced by the wet web forming method, to inhibit the separation between fibers of the lower absorbent layer, and to continuously maintain the shape of the lower absorbent layer.

[0046] According to a preferred embodiment, the utility model of embodiment 12, based on any one of embodiments 1 to 11, may have the following feature: the thickness of the lower absorbent layer after fluid absorption is less than 150% of its thickness before fluid absorption. According to this embodiment, changes in the shape and thickness of the lower absorbent layer can be suppressed, and the bonding state with respect to the garment can be maintained relative to the adhesive surface.

[0047] According to a preferred embodiment, the utility model of embodiment 13, based on any one of embodiments 1 to 12, may have the following feature: the thickness of the absorbent body after absorption of the body fluid is 300% or less, relative to its thickness before absorption. According to this embodiment, since the thickness does not become excessive during absorption of the body fluid, discomfort caused by the thickening of the absorbent body can be suppressed.

[0048] According to a preferred embodiment, the utility model of embodiment 14, based on any of embodiments 1 to 13, may have the following features: The permeability of the highly absorbent polymer in the upper absorbent layer is higher than that of the highly absorbent polymer in the lower absorbent layer. According to this embodiment, because the highly absorbent polymer in the upper absorbent layer has higher permeability, it can rapidly absorb bodily fluids. By utilizing the upper absorbent layer to retain bodily fluids, the absorption capacity of the lower absorbent layer can be continuously ensured. Even with repeated expulsion of bodily fluids, the lower absorbent layer can absorb bodily fluids, thus continuously retaining bodily fluids even after prolonged use.

[0049] According to a preferred embodiment, the utility model of embodiment 15, based on any of embodiments 1 to 14, may have the following features: The average inter-fiber distance of the lower absorbent layer is shorter than that of the upper absorbent layer. According to this embodiment, the lower absorbent layer has a shorter average inter-fiber distance and fewer gaps between fibers, thus suppressing excessive expansion of the highly absorbent polymer and controlling the thickness of the absorbent during swelling. Therefore, changes in the thickness of the lower absorbent layer can be suppressed, ensuring that the bonding state with respect to the garment is maintained relative to the adhesive surface. Furthermore, since the inter-fiber distance of the lower absorbent layer is shorter than that of the upper absorbent layer, the transferability of bodily fluids from the upper absorbent layer to the lower absorbent layer is improved. Bodily fluids guided to the upper absorbent layer can diffuse along the planar direction within the upper absorbent layer while also being guided to the lower absorbent layer on the non-skin side, and can also diffuse along the planar direction within the lower absorbent layer.

[0050] According to a preferred embodiment, the utility model of embodiment 16, based on any of embodiments 1 to 15, may have the following features: The thickness of the upper absorbent layer is less than 3 mm. The thickness of the lower absorbent layer is less than 2.5 mm. The overall thickness of the absorbent body is less than 6.5 mm. According to this embodiment, because the upper and lower absorbent layers are relatively thin, the absorbent body is easily and softly deformable, easily conforming to the body, and can suppress discomfort during wear. Furthermore, because the overall thickness of the absorbent body is relatively thin, it can suppress discomfort when the side of the absorbent body touches the groin area.

[0051] (2) Overall general structure of absorbent materials

[0052] Hereinafter, the absorbent article 1 according to the embodiments will be described with reference to the accompanying drawings. Figure 1 This is a schematic top view of the absorbent article as seen from the skin side, according to the embodiment. Figure 2 This is a schematic top view of the absorbent article as described in the embodiment, viewed from the non-skin side. Figure 3 It is along Figure 1 The cross-sectional view shown along line AA. Figure 3 For ease of explanation, the components constituting absorbent article 1 are partially separated in the thickness direction; however, in the actual product, there are joints between the components. Furthermore, in the following drawings, similar or identical reference numerals are used to label the same or similar parts. However, it should be noted that the drawings are schematic, and the proportions of the dimensions may differ from reality. Therefore, specific dimensions should be determined by referring to the following description. Additionally, the drawings may include portions with different dimensional relationships or proportions.

[0053] The absorbent article 1 can be an absorbent article such as a sanitary napkin, panty liner, urinary pad, or fecal pad. The absorbent article 1 can be an article used by attaching it to clothing such as underwear. In this embodiment, the absorbent article 1 is an urinary pad. The absorbent article 1 is an absorbent article primarily intended to absorb urine, and unlike a sanitary napkin, it is not primarily intended to absorb menstrual blood, nor like a panty liner, it is not primarily intended to absorb vaginal discharge.

[0054] The absorbent article 1 has mutually orthogonal front-to-back direction L and width direction W, and a thickness direction T extending from the wearer's skin side T1 to the non-skin side T2. The skin side T1 corresponds to the side facing the wearer's skin during use. The non-skin side T2 corresponds to the side opposite to the skin side T1 during use, i.e., the side facing away from the wearer's skin. The absorbent article 1 has a crotch area S1, a front area S2, and a rear area S3. The crotch area S1 is the area positioned opposite the wearer's excretory opening (urination opening). When the absorbent article 1 is installed in underwear, the crotch area S1 is the area positioned in the crotch region of the underwear and between the wearer's legs. The crotch area S1 may be composed of an area with wings 40 described later. The front area S2 is located further forward than the crotch area S1. The rear area S3 is located further back than the crotch area S1.

[0055] Furthermore, in this invention, the outer portion refers to the part occupying a certain range in the width direction W, including the outer edge in the width direction W. The outer edge refers to the outer edge in the width direction W. Additionally, the outer edge of a constituent member occupying a certain range in the front-rear direction L is an edge obtained by connecting all points of the constituent member located on the outer side in the width direction W throughout the constituent member. In this invention, the inner portion refers to the part occupying a certain range in the width direction W, including the inner edge in the width direction W. The inner edge refers to the inner edge in the width direction W. Additionally, the inner edge of a constituent member occupying a certain range in the front-rear direction L is an edge obtained by connecting all points of the constituent member located on the inner side in the width direction W throughout the constituent member. Furthermore, in this invention, the front end and rear end are portions occupying a certain range in the front-rear direction L, including the edges in the front-rear direction L. The front edge and rear edge are edges in the front-rear direction L. The outer end includes the front end and the rear end, and the outer edge includes the front edge and the rear edge. Furthermore, the inner side is an edge that includes the inner edge and extends along the front-rear direction L. The outer edge is an edge that includes the outer edge and extends along the front-back direction L. Furthermore, in this specification, the term "along the front-back direction L" refers to a direction with an angle of less than 45° relative to the front-back direction L, and the term "along the width direction W" refers to a direction with an angle of less than 45° relative to the width direction W.

[0056] The absorbent article 1 may have at least an absorbent body 30, a top sheet 10, and a bottom sheet 20. The top sheet 10 is a sheet material disposed at a position closer to the skin (T1) than the absorbent body 30 and abutting against the wearer. The top sheet 10 may have a top central sheet 11 that overlaps with the center of the absorbent body 30 in the width direction W, and a top side sheet 12 that overlaps with the outer portion of the top central sheet 11 in the width direction W. The top side sheet 12 may also be disposed at a position closer to the skin (T1) than the top central sheet 11. The top side sheet 12 may cover the skin-side (T1) surface of the top central sheet 11 and fold back towards the non-skin side with the outer portion of the absorbent body 30 as a base point. The top side sheet 12 may cover a portion of the non-skin-side (T2) surface of the absorbent body 30.

[0057] In a modified example, the top sheet 10 may be composed of a single sheet instead of a central top sheet 11 and a side top sheet 12. The central top sheet 11 and the side top sheet 12 may be made of nonwoven fabric, or at least the central top sheet 11 may be liquid-permeable, and the side top sheet 12 may have a hydrophobic surface treatment.

[0058] The absorbent article has an absorbent body 30 disposed on the non-skin side of the top sheet. The absorbent body 30 has an absorbent material that absorbs bodily fluids. The absorbent material includes fibers such as pulp and a highly absorbent polymer. The absorbent body 30 may have an upper absorbent layer 31 and a lower absorbent layer 32 disposed on the non-skin side of the upper absorbent layer 31. The absorbent materials of the upper absorbent layer 31 and the lower absorbent layer 32 may both contain fibers and a highly absorbent polymer. The absorbent body 30 may have an intermediate absorbent layer 33 disposed between the upper absorbent layer 31 and the lower absorbent layer 32. The absorbent material of the intermediate absorbent layer 33 may not contain a highly absorbent polymer but may contain fibers. The absorbent material of the intermediate absorbent layer 33 may contain at least fibers. The structure of the absorbent body 30 will be described in detail later.

[0059] The absorbent article has a backing sheet 20 disposed at a position closer to the skin side T2 than the absorbent body 30 and constituting the non-skin side of the absorbent article. The backing sheet 20 may be liquid-impermeable and made of a membrane. In the absorbent article installed on a garment, a fastening portion 60 for securing the absorbent article 1 to the underwear may be provided on the non-skin side of the backing sheet 20. The fastening portion 60 may have at least a main fastening portion 61 disposed in the area overlapping with the absorbent body 30 and a wing fastening portion 62 disposed in the wing portion 40. An adhesive or hook and loop fastener may be provided on the fastening portion 60. The main fastening portion 61 may be secured by a main body peel-off sheet 65 (see reference) before using the absorbent article 1. Figure 2 The wing attachment 62 is covered by a wing stripper (not shown).

[0060] The absorbent article 1 may have a second sheet 13. The second sheet 13 is positioned on the skin side T1 of the absorbent body 30 and on the non-skin side T2 of the top sheet 10, guiding bodily fluids towards the absorbent body 30. The length L in the anteroposterior direction of the second sheet 13 may be shorter than the length L in the anteroposterior direction of the absorbent body 30. The outer edge of the second sheet 13 may be located inside the outer edge of the absorbent body 30 in the anteroposterior direction L. The outer edge of the second sheet 13 may be located inside the outer edge of the absorbent body 30 in the width direction W, and may be located inside the outer edge of the top central sheet 11 in the width direction W. The second sheet 13 may be made of nonwoven fabric, preferably hot-air nonwoven fabric. Alternatively, the absorbent article 1 may not have a second sheet 13.

[0061] A compression section 80, formed by compressing the absorbent body 30 along the thickness direction T, can be provided in the absorbent article 1. Regarding the compression section 80, it is possible to compress the absorbent body 30 and the top sheet 10, or to compress the absorbent body 30, the top sheet 10, and the second sheet 13 together, or to compress only the absorbent body 30. Preferably, the compression section 80 can be formed by compressing the top sheet 10, the absorbent body 30, and the second sheet 13 together from the skin side T1 towards the non-skin side T2.

[0062] The absorbent article 1 may have a pair of wings 40 extending outward in the width direction W of the absorbent body 30, and folding back towards the non-skin side of the underwear when worn. The wings 40 may be spaced apart in the width direction W. The wings 40 are positioned in the crotch region S1, with the front edge of the wings 40 forming the front edge of the crotch region S1 and the rear edge of the wings 40 forming the rear edge of the crotch region S1. Side panels 15 and a bottom panel 20 may be disposed on the wings 40. The side panels 15 are positioned further outward in the width direction than the top side panel 12 disposed on the non-skin side of the absorbent body 30.

[0063] The absorbent article 1 of this embodiment is configured such that even when a large amount of bodily fluid is expelled at once, the skin-side surface of the absorbent article is easily kept dry, and discomfort caused by the thickness of the absorbent body 30 during wear can be suppressed. Next, the structure for easily keeping the skin-side surface of the absorbent article dry and suppressing discomfort caused by the thickness of the absorbent body 30 during wear, even when a large amount of bodily fluid is expelled at once, will be described in detail.

[0064] The density of the lower absorbent layer 32 can be higher than that of the upper absorbent layer 31. A higher density in the lower absorbent layer 32 results in fewer gaps between the fibers, thus suppressing excessive expansion of the highly absorbent polymer and controlling the thickness of the absorbent body 30 during swelling. Therefore, variations in the thickness of the lower absorbent layer 32 can be suppressed, ensuring adhesion to the garment surface and maintaining a bonded state with respect to the garment.

[0065] Here, the density of each absorber is calculated based on the following formula.

[0066] D(g / cm 3 )=B(g / m 2 ) / T(mm)×10 -3

[0067] [In the formula, D, B, and T represent the density, weight per unit area, and thickness of the absorber of this invention, respectively.]

[0068] In addition, the unit area weight (g / m²) of absorber 30 2 The measurement is calculated based on the following: Three 100mm × 100mm test pieces are cut from each absorber 30. The mass of each test piece under standard conditions (temperature 23±2℃, relative humidity 50±5%) is measured using a direct-reading balance (e.g., Kensei Kogyo Co., Ltd. electronic balance HF-300). The mass per unit area (g / m²) of the absorber 30 is calculated from the average of the three measurements. 2 The weight per unit area of ​​absorber 30 is used. Furthermore, for the measurement of the weight per unit area of ​​absorber 30, unless otherwise specified above, the measurement conditions described in ISO 9073-1 or JIS L1913 6.2 shall be used.

[0069] The thickness (mm) of the absorber 30 is measured as follows: A thickness gauge (e.g., FS-60DS manufactured by Daiei Scientific Instruments Co., Ltd., with a measuring surface diameter of 44mm and a measuring pressure of 3g / cm) is used. 2 ), at a constant pressure of 3g / cm 2 Five different locations of the absorber 30 under standard conditions (temperature 23±2℃, relative humidity 50±5%) (each location has a diameter of 44mm when using a thickness gauge FS-60DS) were pressurized, and the thickness at each location was measured after 10 seconds of pressurization. The average of the five measurements was taken as the thickness of the absorber 30.

[0070] The upper absorbent layer 31 can have a high weight ratio of highly absorbent polymer relative to the total weight of the absorbent material of 50% or more. The lower absorbent layer 32 can also have a high weight ratio of highly absorbent polymer relative to the total weight of the absorbent material of 50% or more. Because both the upper absorbent layer 31 and the lower absorbent layer 32 have a high weight ratio of highly absorbent polymer, they exhibit high retention performance for bodily fluids such as urine. Even when a large amount of bodily fluid is expelled at once, it is easy to retain bodily fluids and keep the skin-side of the absorbent item 1 dry. Because the absorbent material contains a low weight ratio of fibers, it is easy to make the absorbent body 30 thinner. This helps to suppress discomfort caused by a thicker absorbent body 30 during wear.

[0071] The weight ratio of the highly absorbent polymer in the upper absorbent layer 31 can be higher than that in the lower absorbent layer 32, and the weight per unit area of ​​the highly absorbent polymer in the upper absorbent layer 31 can be higher than that in the lower absorbent layer 32.

[0072] The upper absorbent layer 31 may have multiple sheets and a highly absorbent polymer disposed between the sheets. That is, the upper absorbent layer 31 may be a so-called SAP sheet. The highly absorbent polymer may not be bonded to the sheets using an adhesive, but rather by welding multiple sheets together. That is, the upper absorbent layer 31 may not have an adhesive, solvent, or other binder for bonding the absorbent material. In the upper absorbent layer 31 of this embodiment, the highly absorbent polymer is held in place by a hot-air nonwoven fabric and the hot-air nonwoven fabric is heat-treated, thereby melting the fibers of the hot-air nonwoven fabric to fuse the highly absorbent polymer to the hot-air nonwoven fabric. According to this method, since the highly absorbent polymer is bonded by welding rather than using an adhesive, compared to a structure where the upper absorbent layer 31 has an adhesive, the obstruction of body fluid by the adhesive can be suppressed, and the diffusion of body fluid within the upper absorbent layer 31 and the transfer of body fluid to the lower absorbent layer 32 can be improved. Furthermore, compared to the structure of the upper absorbent layer 31 which has an adhesive, the fibers do not solidify with each other due to the adhesive, and the highly absorbent polymer can easily move within the absorbent body 30. The absorbed highly absorbent polymer can move in a planar direction, easily deforming and conforming to the body's contours. The absorbent material of the upper absorbent layer 31 contains a highly absorbent polymer. The absorbent material of the upper absorbent layer 31 may be without pulp, or it may contain pulp at a weight ratio less than that of the highly absorbent polymer.

[0073] Alternatively, the lower absorbent layer 32 may not be bonded using an adhesive, but rather cured by the intertwining of fibers. That is, the lower absorbent layer 32 may not contain adhesives or other binders for bonding the absorbent material. The absorbent body 30 cured by the intertwining of fibers can be manufactured, for example, by forming a fiber laminate using a dry or wet method, followed by pressing with heated rollers, welding with air heating, or interlacing the fibers using high-pressure water jets. According to this method, compared to a structure where the lower absorbent layer 32 has an adhesive, the fibers do not cure due to the adhesive, and the highly absorbent polymer easily moves within the lower absorbent layer 32. The absorbed highly absorbent polymer can move in the planar direction, easily deforming and conforming to the body's contours. The lower absorbent layer 32 of this embodiment is an absorbent body 30 formed by processing the highly absorbent polymer and fibers using a wet web forming (wet method). The absorbent 30 manufactured using wet web forming has fewer gaps between fibers, which can suppress the expansion of highly absorbent polymers and prevent the absorbent 30 from becoming too thick.

[0074] The non-skin side sheet, which abuts against the non-skin side T2 of the lower absorbent layer 32, can have higher liquid diffusivity than the lower absorbent layer 32. This promotes the transfer of body fluid from the lower absorbent layer 32 to the non-skin side sheet. In particular, in the lower absorbent layer 32 manufactured by wet web forming, it is possible to suppress the continuous accumulation of body fluid within the lower absorbent layer 32 and to suppress the separation between the fibers of the lower absorbent layer 32, thus maintaining the shape of the lower absorbent layer 32. In this embodiment, the non-skin side T2 at the center of the width direction W of the lower absorbent layer 32 abuts against the substrate 20, and the non-skin side T2 at the side portion of the width direction W of the lower absorbent layer 32 abuts against the side sheet 15. The liquid diffusivity of the side sheet 15 can be higher than that of the lower absorbent layer 32.

[0075] The upper absorbent layer 31 can be thicker than the lower absorbent layer 32. Because the upper absorbent layer 31 is thicker, it provides better cushioning and retains its thickness even after absorption. Therefore, it easily maintains its shape even under external forces such as body movements, reducing discomfort. Conversely, because the lower absorbent layer is thinner, it easily follows the deformation of the upper absorbent layer while maintaining the overall thinness of the absorbent body, further reducing discomfort during wear and after absorption.

[0076] The thickness of the upper absorbent layer 31 can be less than 3 mm. The thickness of the lower absorbent layer 32 can be less than 2.5 mm. Because the upper and lower absorbent layers 32 are relatively thin, the absorbent body 30 is easily deformable and can easily follow the body, thus suppressing discomfort when wearing it. Furthermore, the overall thickness of the absorbent body 30 can be less than 6.5 mm. Because the overall thickness of the absorbent body 30 is relatively thin, discomfort when the side of the absorbent body 30 touches the groin area can be suppressed. The overall thickness of the absorbent body 30 only needs to be the sum of the thickness of the upper absorbent layer 31 and the lower absorbent layer 32, and this sum can be less than 6.5 mm, preferably less than 2 mm. The overall thickness of the absorbent body 30 can be the sum of the thickness of the upper absorbent layer 31, the lower absorbent layer 32, and the middle absorbent layer 33, and the thickness of these three layers can be less than 6.5 mm, preferably less than 2 mm. In addition, the thickness of the lower absorption layer 32 is preferably less than 1.0 mm, and more preferably less than 0.6 mm.

[0077] The thickness of the lower absorbent layer 32 after absorption of body fluid, relative to its thickness before absorption, can be 150% or less. According to this method, changes in the shape and thickness of the lower absorbent layer 32 can be suppressed, ensuring that the bonding state with the garment is maintained relative to the adhesive surface. Furthermore, the thickness of the absorbent body 30 after absorption of body fluid, relative to its thickness before absorption, can be 300% or less. According to this method, since the thickness does not become excessive during absorption of body fluid, discomfort caused by the thickening of the absorbent body 30 can be suppressed. In addition, regarding the thickness before absorption of body fluid, after removing the absorbent article 1 from the packaging, separation is performed using cold spraying with liquid nitrogen or the like, removing the absorbent body from the absorbent article. For areas excluding compression sections, samples are cut at 60mm x 60mm, taking into account the width of the absorbent body. Five such samples are prepared, their thickness is measured, and the average value of the five samples is taken. Regarding the thickness after fluid absorption, a specified amount of liquid (20 ml) was dripped onto the sample cut using the above method using a dropper, and the thickness was measured after 5 minutes. The average of 5 samples was then taken. The thickness after fluid absorption, relative to the thickness before fluid absorption, was calculated by dividing the thickness after fluid absorption by the thickness before fluid absorption.

[0078] The lengths of the upper absorbent layer 31 and the lower absorbent layer 32 in the width direction can be different. By making the lengths of the upper absorbent layer 31 and the lower absorbent layer 32 in the width direction different, the outer portion of the absorbent body in the width direction is thinner, which can suppress discomfort when the absorbent body touches the groin area. In addition, the maximum length of the upper absorbent layer 31 in the width direction can be longer than the maximum length of the lower absorbent layer 32 in the width direction, and can also be longer than the maximum length of the middle absorbent layer in the width direction. Furthermore, the maximum lengths of the upper absorbent layer 31 in the front-back direction, the lower absorbent layer 32 in the front-back direction, and the middle absorbent layer in the front-back direction can be approximately the same, and can be more than 95% and less than 105% of the average length.

[0079] The bending stiffness of the lower absorbent layer 32 can be higher than that of the upper absorbent layer 31. Since the upper absorbent layer 31 has a lower bending stiffness, it can reduce discomfort relative to the body, and it is also easier to conform to the body's contours. Since the lower absorbent layer 32 has a higher bending stiffness, it is easier to maintain a flat shape on the non-skin side of the absorbent material, making it easier to install in clothing such as underwear, and also easier to maintain a proper fit with the clothing. Here, the bending stiffness can be measured using the KES method. Specifically, a KES-FB2-AUTO-A bending tester manufactured by KATO TECH Co., Ltd. can be used to prepare samples capable of measuring the dimensions of the cover sheet and the inspection component. For the bending stiffness of the inspection component, it is preferable to cut the sample in a manner that includes the portion containing the antibody, and measure the stiffness of the portion containing the antibody. Next, each sample is fixed between the chucks of the testing machine so that the lateral bending stiffness of each sample can be measured. The sample was bent towards the front side until the maximum curvature was increased by 2.5 cm⁻¹, then towards the back side until the maximum curvature was decreased by 2.5 cm⁻¹, before returning to its original position. The bending stiffness value was calculated based on the average of the inclination angles at the start of bending towards the front side when the bending moment relative to the curvature was approximately constant, and the inclination angles at the start of bending towards the back side when the bending moment relative to the curvature was approximately constant. This process was repeated 5 times for each sample, and the average value was taken as the bending stiffness.

[0080] The tensile strength of the upper absorbent layer 31 when wet can be higher than that of the lower absorbent layer 32 when wet. The higher tensile strength of the upper absorbent layer 31 when wet helps to suppress deformation during use. Even with prolonged use or absorption of large amounts of bodily fluids, deformation of the upper absorbent layer 31 located on the skin side can be suppressed, thus continuously reducing discomfort during wear. Preferably, the tensile strength of the upper absorbent layer 31 when wet can be 10 N / 25 cm or higher. Here, the tensile strength can be measured using a tensile testing machine manufactured by INSTRON Corporation, with the sample of the test object cut at a width of 25 mm and the sample completely wetted with water.

[0081] The average interfiber distance of the lower absorbent layer 32 can be shorter than that of the upper absorbent layer 31. With a shorter average interfiber distance and fewer gaps between fibers in the lower absorbent layer 32, excessive expansion of the highly absorbent polymer can be suppressed, thus reducing the thickness of the absorbent during swelling. Therefore, changes in the thickness of the lower absorbent layer 32 can be suppressed, ensuring adhesion to the garment and maintaining a bond with the garment. Furthermore, since the interfiber distance of the lower absorbent layer 32 is shorter than that of the upper absorbent layer 31, the transfer of bodily fluids from the upper absorbent layer 31 to the lower absorbent layer 32 can be improved. Bodily fluids guided to the upper absorbent layer 31 can diffuse along a planar direction within the upper absorbent layer 31 while simultaneously being guided to the lower absorbent layer 32 on the non-skin side, and can also diffuse along a planar direction within the lower absorbent layer 32.

[0082] Regarding the evaluation of average interfiber distance, for example, the average interfiber distance can be measured using a microscope on the surface of the object being measured, and also using a microscope on the non-skin side of the film 20. For the microscope method, a focused magnified image is obtained from the skin side of the sample to a depth of 100 μm using the 3D image linking function of the microscope (KEYENCE VHX-2000, lens VH-Z20W, open aperture), and the outer side of the focused fibers is extracted based on this magnified image. The surface formed therein is defined as the fiber space. The diameter of the largest inscribed circle of this fiber space is defined as the fiber space distance, and the average value of the amount at 100 μm in the fiber space is defined as the average interfiber distance.

[0083] The permeability of the superabsorbent polymer in the upper absorbent layer 31 can be higher than that of the superabsorbent polymer in the lower absorbent layer 32. Because of the higher permeability of the superabsorbent polymer in the upper absorbent layer 31, bodily fluids can be rapidly absorbed in the upper absorbent layer 31. By utilizing the upper absorbent layer 31 to retain bodily fluids, the absorption capacity of the lower absorbent layer 32 can be continuously ensured. Even after repeated expulsion of bodily fluids, the lower absorbent layer 32 can absorb bodily fluids, thus maintaining bodily fluid retention even with prolonged use.

[0084] The permeability of highly absorbent polymers can be evaluated, for example, using a permeability evaluation device. The permeability evaluation using the permeability evaluation device is performed as follows: (i) The sample to be measured is placed on a sample stage with a 10° inclination. The sample is measured with 10g of highly absorbent polymer being held between identical nonwoven fabric sheets. A circular hole with a diameter of 65mm is provided on the sample-placed surface of the sample stage. (ii) Using a 5mm diameter tube, 100ml of artificial urine is dripped from a height of 80mm over 3.75 seconds. The dripped artificial urine permeates the sample and passes through the hole in the sample stage into a recovery dish.

[0085] (iii) Measure the weight of the artificial urine that enters the recovery dish.

[0086] (iv) Calculate the permeability according to the following formula.

[0087] Permeability (%) = Weight of artificial urine entering the recovery dish (g) / 25 (g) × 100

[0088] Highly absorbent polymers with higher permeability have higher permeability, while highly absorbent polymers with lower permeability have lower permeability.

[0089] The compression section 80 can compress the upper absorbent layer 31 and the lower absorbent layer 32 along the thickness direction. According to this method, the upper absorbent layer 31 and the lower absorbent layer 32 are joined using the compression section 80. By joining the upper absorbent layer 31 and the lower absorbent layer 32 using the compression section 80, positional shift of the upper absorbent layer 31 and the lower absorbent layer 32 can be suppressed, and the overall thickness of the absorbent body can be reduced, thus reducing discomfort during wear. Furthermore, since the upper absorbent layer 31 and the lower absorbent layer 32 are joined by the compression section 80, the transfer of bodily fluids from the upper absorbent layer 31 to the lower absorbent layer 32 can be promoted. Moreover, in the region overlapping with the intermediate absorbent layer, the compression section can compress the upper absorbent layer 31, the intermediate absorbent layer 33, and the lower absorbent layer 32 together, thus joining them.

[0090] Figure 4 This is a top view of the intermediate absorbent layer 33. The intermediate absorbent layer 33 may have an opening 34 that extends through it in the thickness direction. The opening 34 is positioned at the center of the width direction W in the crotch region S1 of the absorbent article 1. The center of the width direction W in the crotch region S1 of the absorbent article 1 is an area that is easily positioned opposite to an excretion opening and easily guides bodily fluids. According to this method, the transfer of bodily fluids from the upper absorbent layer 31 to the lower absorbent layer 32 can be facilitated by means of the opening 34 of the intermediate absorbent layer 33. The opening 34 is made of fibers in the absorbent material with a unit area weight of 0 g / m².3 This is part of the fiber. Furthermore, the fiber's area weight is 0 g / m². 3 The part whose unit area weight is 0g / m² in the design 3 Alternatively, fibers that float from the surrounding area can be provided. Furthermore, a highly absorbent polymer can be provided in the opening 34 of this embodiment. The structure in which a highly absorbent polymer is provided in the opening will be described later.

[0091] The opening 34 may be at least partially disposed in the groin region S1, and may extend across the front region S2 or the rear region S3. The center of the opening 34 in the front-rear direction L may be located in a position further forward than the center of the groin region S1 in the front-rear direction L. As for the excretion opening, it is easy to arrange it opposite to a region further forward than the center of the groin region S1 in the front-rear direction L, and by having the center of the opening 34 in the front-rear direction L located further forward than the center of the groin region S1 in the front-rear direction L, it is easier and smoother to introduce bodily fluids into the opening 34. The maximum width of the opening 34 may be more than 50% of the entire area in the width direction W of the intermediate absorbent layer 33, and may also be more than 50% of the entire area in the width direction W of the absorbent body 30.

[0092] The upper absorbent layer 31 and the lower absorbent layer 32 can be joined within the opening 34. This can suppress positional displacement of the upper absorbent layer 31 and the lower absorbent layer 32, and can also suppress the overall thickness of the absorbent body 30 and reduce discomfort during wear. In addition, since the upper absorbent layer 31 and the lower absorbent layer 32 are tightly sealed within the opening 34, it can promote the transfer of bodily fluids from the upper absorbent layer 31 to the lower absorbent layer 32.

[0093] The absorber has an open absorbent layer with an opening 34 extending through the thickness direction. The opening 34 is located in an intermediate absorbent layer 33, which constitutes the "open absorbent layer" of this invention. In this embodiment, the "open absorbent layer" is formed by the intermediate absorbent layer 33, but in variations, it may be formed by at least one of an upper absorbent layer 31 and a lower absorbent layer 32. The opening 34 has a first region R1 and a second region R2. The second region R2 is located outside the first region R1 in the front-rear direction L, and its width direction length is longer than that of the first region. The first region R1 and the second region R2 are adjacent regions in the front-rear direction L within a single opening 34. The maximum width of the second region R2 is longer than the maximum width of the first region R1. In this embodiment, where the length of the opening 34 gradually changes in the width direction W, the midpoint between the shortest and longest maximum width positions can be used as the boundary between the first region R1 and the second region R2. Figure 4This indicates the boundary between region R1 and region R2. By having region R1 and region R2 with different lengths in the width direction W in the opening 34, even if region R1 is crushed when subjected to a force inward in the width direction due to a leg or the like, region R2 is less likely to be crushed, thus preventing the entire opening 34 from being crushed.

[0094] A highly absorbent polymer can be disposed at the opening 34. Alternatively, a highly absorbent polymer can be disposed at the opening 34 instead of fibers such as pulp. The highly absorbent polymer at the opening 34 can be used to retain bodily fluids. Since a highly absorbent polymer is disposed at the opening 34 instead of fibers such as pulp, the decrease in the diffusion rate of bodily fluids due to the presence of fibers can be suppressed, and the absorption capacity of bodily fluids can be ensured using the highly absorbent polymer. Furthermore, the opening 34 is disposed at the center of the width direction W in the crotch area S1 of the absorbent article 1, and in the area opposite to the excretion opening. By disposing of a highly absorbent polymer at the opening, which facilitates the guidance of bodily fluids from the excretion opening, the retention performance of bodily fluids such as urine can be improved.

[0095] The area weight of the highly absorbent polymer at the opening 34 can be lower than that of the highly absorbent polymer in the opening absorbent layer surrounding the opening 34. Because of the lower area weight of the highly absorbent polymer at the opening 34, gel blockage at the opening 34 is suppressed, and the transfer of bodily fluids through the opening 34 to the non-skin side is less likely to be impeded. Because of the higher area weight of the highly absorbent polymer in the intermediate absorbent layer surrounding the opening 34, bodily fluids are easily retained in the surrounding area, ensuring absorption capacity.

[0096] The absorbent 30 may have a cover sheet covering the opening 34. The presence of the cover sheet easily suppresses deformation of the opening 34 and helps maintain the shape of the opening 34. Furthermore, the cover sheet only needs to cover at least a portion of the opening 34, but preferably it can cover the entire area of ​​the opening 34. The cover sheet can be disposed on the skin side T1 of the opening absorbent layer having the opening 34, or on the non-skin side T2 of the opening absorbent layer. In this embodiment, the cover sheet is composed of a sheet material sandwiched with a highly absorbent polymer in the upper absorbent layer 31, covering the entire area of ​​the skin side T1 of the opening 34.

[0097] The absorbent 30 may have a covering absorbent layer that overlaps with the opening 34 and is made of a highly absorbent polymer. The highly absorbent polymer of the covering absorbent layer swells upon absorbing body fluid, thereby supporting the opening 34, easily suppressing deformation of the opening 34, and ensuring the area of ​​the opening 34. Furthermore, the covering absorbent layer may only need to cover at least a portion of the opening 34, but preferably it may cover the entire area of ​​the opening 34.

[0098] The covering absorbent layer can be disposed on the skin side T1 of the opening absorbent layer having the opening 34, or on the non-skin side T2 of the opening absorbent layer. Preferably, the covering absorbent layer can be disposed on both the skin side T1 and the non-skin side T2 of the opening 34. According to this method, since the covering absorbent layer is disposed to hold the opening 34, it is easier to maintain the shape of the opening 34. The covering absorbent layer of this embodiment is composed of an upper absorbent layer 31 and a lower absorbent layer 32, covering the entire area of ​​the opening 34 on the skin side T1 and the non-skin side T2.

[0099] A colored layer can be disposed on the non-skin side of the opening 34. The colored layer can be configured to be visually recognizable from the skin side T1 of the absorbent article 1. Furthermore, "visually recognizable" refers to the ability of a subject with good visual acuity (1.0 or better) to visually recognize an object at a distance of approximately 30cm to 50cm in a brightly lit room (reference value: 500lx to 750lx) with daylight color (color temperature reference value 4600K to 5400K (Kelvin)). According to this method, the user can easily notice the presence of the opening 34 by visually recognizing the colored layer from the skin side T1 of the absorbent article 1 through the opening 34. In this embodiment, the colored layer is composed of the lower absorbent layer 32.

[0100] The compression portion 80 may extend across the outer edge of the opening 34. According to this method, the compression portion 80 can easily be used to increase the rigidity of the outer edge of the opening 34, and the shape of the opening 34 can be easily maintained. The compression portion 80 only needs to extend across at least a portion of the outer edge of the opening 34. Preferably, the compression portion 80 may extend across the outer edge of the outer edge of the opening 34 located on the outer side in the width direction W and extending along the front-rear direction L; more preferably, the compression portion 80 may extend across the side edges of the outer edge of the opening 34 located on both sides in the width direction W. In this embodiment, multiple compression portions 80 are provided at intervals along the side edges of the opening 34 in the front-rear direction L. According to this structure, it is easy to suppress the side edges of the opening 34 from entering the inner side, and it is easier to ensure the area of ​​the opening 34. The compression portion 80 may have a compression portion extending across the outer edge of the opening 34, and a compression portion separated from the outer edge of the opening and located on the outer side in the width direction beyond the outer edge of the opening. The compression portion across the outer edge of the opening 34 can maintain the shape of the opening and improve the introduction of body fluid to the non-skin side. Furthermore, the compression portion located on the outer side of the opening in the width direction can improve the introduction of body fluid that diffuses to the outer side in the width direction, thereby suppressing side leakage.

[0101] The open-ended absorbent layer may have outer regions R10 located on the outer edges of the two sides of the opening 34 in the width direction, further outward in the width direction. The fastening portions may be disposed in the regions overlapping with the outer regions R10. The outer regions R10 are the areas between the outer edges of the opening 34 and the outer edges of the open-ended absorbent layer. In this embodiment, the "fastening portion" is composed of a main fastening portion 61. The main fastening portion 61 is disposed in the region overlapping with the outer regions R10. According to this method, when the outer regions R10 located on the outer side of the opening 34 in the width direction are pressed towards the wearer, the two outer edges of the opening 34 are less likely to move inward in the width direction, thereby easily maintaining the shape of the opening 34. The main fastening portion 61, as the fastening portion, may span the outer edge of the opening 34. According to this method, the main fastening portion 61 can easily be used to suppress the outer edge of the opening 34 from entering inward, easily ensuring the area of ​​the opening 34. The length of the opening 34 in the width direction at its maximum position can be longer than the length of each outer region R10 in the width direction. Preferably, the length of the opening 34 in the width direction at its maximum position can be 60% or more, more preferably 70% or more, relative to the length of the intermediate absorbent layer in the width direction. The opening can be provided with a larger width, which can improve the transferability of body fluids to the non-skin side.

[0102] Multiple regions R1 and R2 can be alternately arranged in the front-rear direction L. That is, regions R1, R2, R1, and R2 can be arranged along the front-rear direction L. According to this method, when a force is applied inward toward the width direction W, multiple regions R1 can absorb the force, the opening state of multiple regions R2 can be maintained, and the overall crushing of the opening 34 can be prevented.

[0103] Next, refer to Figure 5 Explain the opening 34X in the modified example. Figure 5 This is a top view of the intermediate absorbent layer 33X of the opening absorbent layer as a modified example. Furthermore, in the following description of the modified examples, the same reference numerals are used for structures identical to those in the above-described embodiment, and descriptions are omitted. For the opening 34 in the embodiment, the first region and the second region are alternately arranged, and the outer edge of the opening is wavy. In contrast, the opening 34X in the modified example is teardrop-shaped in top view, and the outer edge of the opening 34X is a curved shape bulging outwards. Additionally, for the opening 34X in the modified example, one second region R2 is arranged to be sandwiched between the first region R1. In the teardrop-shaped opening 34X of the modified example, the presence of the first region R1 and the second region R2 allows bodily fluids to easily enter the opening even when subjected to lateral force during wear, thus maintaining the permeability of bodily fluids.

[0104] The present invention has been described in detail above using the embodiments described above. However, it will be apparent to those skilled in the art that the present invention is not limited to the embodiments described herein. The present invention can be implemented as modifications and variations without departing from the spirit and scope of the present invention as defined by the claims. Therefore, the description in this specification is for illustrative purposes only and does not have any limiting meaning for the present invention.

Claims

1. An absorbent article comprising: a front-to-back direction, a width direction, and a thickness direction, which are orthogonal to each other; a top sheet that abuts against the wearer's skin; and an absorbent body disposed at a position closer to the non-skin side than the top sheet, having an absorbent material for absorbing bodily fluids, the absorbent body having an upper absorbent layer and a lower absorbent layer disposed at a position closer to the non-skin side than the upper absorbent layer, characterized in that, The absorbent material of the upper absorbent layer and the absorbent material of the lower absorbent layer comprise fibers and highly absorbent polymers. The density of the lower absorption layer is higher than that of the upper absorption layer. The weight ratio of the highly absorbent polymer in the upper absorbent layer relative to the total weight of the absorbent material is 50% or more. The weight ratio of the highly absorbent polymer in the lower absorbent layer relative to the total weight of the absorbent material is 50% or more.

2. The absorbent article according to claim 1, characterized in that, The upper absorbent layer has multiple sheets and a highly absorbent polymer disposed between the sheets. The highly absorbent polymer is not bonded to the sheet using an adhesive, but rather by welding the plurality of sheets together.

3. The absorbent article according to claim 2, characterized in that, The lower absorbent layer is not bonded using an adhesive, but rather cured by the intertwining of fibers.

4. The absorbent article according to any one of claims 1 to 3, characterized in that, The thickness of the upper absorption layer is greater than the thickness of the lower absorption layer.

5. The absorbent article according to any one of claims 1 to 3, characterized in that, The bending stiffness of the lower absorption layer is higher than that of the upper absorption layer.

6. The absorbent article according to any one of claims 1 to 3, characterized in that, The tensile strength of the upper absorbent layer when wet is higher than that of the lower absorbent layer when wet.

7. The absorbent article according to any one of claims 1 to 3, characterized in that, The absorber has an intermediate absorber layer disposed between the upper absorber layer and the lower absorber layer. The intermediate absorbent layer has an opening in the thickness direction that is centrally located across the crotch area of ​​the absorbent article in the width direction.

8. The absorbent article according to claim 7, characterized in that, The upper absorption layer and the lower absorption layer are joined together within the opening.

9. The absorbent article according to any one of claims 1 to 3, characterized in that, The absorbent article has a compression section formed by compressing the upper absorbent layer and the lower absorbent layer along the thickness direction.

10. The absorbent article according to any one of claims 1 to 3, characterized in that, The lower absorbent layer is an absorbent body manufactured by wet web forming, i.e., wet process.

11. The absorbent article according to claim 10, characterized in that, The absorbent article has a non-skin side sheet that abuts against the non-skin side of the underlying absorbent layer. The non-skin side sheet has higher liquid diffusivity than the lower absorbent layer.

12. The absorbent article according to any one of claims 1 to 3, characterized in that, The thickness of the lower absorbent layer after fluid absorption is less than 150% of its thickness before fluid absorption.

13. The absorbent article according to any one of claims 1 to 3, characterized in that, The thickness of the absorbent after absorption is less than 300% of its thickness before absorption of the body fluid.

14. The absorbent article according to any one of claims 1 to 3, characterized in that, The permeability of the highly absorbent polymer in the upper absorbent layer is higher than that of the highly absorbent polymer in the lower absorbent layer.

15. The absorbent article according to any one of claims 1 to 3, characterized in that, The average inter-fiber distance of the lower absorbent layer is shorter than that of the upper absorbent layer.

16. The absorbent article according to any one of claims 1 to 3, characterized in that, The thickness of the upper absorption layer is less than 3 mm. The thickness of the lower absorption layer is less than 2.5 mm. The overall thickness of the absorber is less than 6.5 mm.

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