Absorbent article

Abstract

To provide an absorbent article capable of suppressing fluid return in which absorbed body fluid returns to a surface sheet.SOLUTION: An absorbent article 1 includes a surface sheet 2 and an absorber 4, has a longitudinal direction X and a transverse direction Y, and includes a belly side part A, a crotch part C, and a back side part B along the longitudinal direction X. The surface sheet 2 includes an uneven structure. In the surface sheet 2, the compressibility calculated by the following formula is lower than that in the absorber 4: The compressibility (%)=(Tb / Ta)×100, Ta representing the thickness in a pressurized state in which the absorbent article is developed and a load of 3kPa is applied, and Tb representing the thickness before pressurization in which the absorbent article is developed and placed under no pressure.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present invention relates to an absorbent article. [Background technology]

[0002] Absorbent articles such as disposable diapers include a topsheet with a concave-convex shape and an absorbent core, which is the main liquid-absorbing portion. Absorbent articles are required to have sufficient absorption performance, be able to prevent leakage of excrement to the outside, and also be thin, soft, and otherwise comfortable to wear. From this perspective, the present applicant previously proposed an absorbent article (Patent Document 1) that includes a topsheet including a first layer formed with a number of convex portions protruding from the surface and having internal cavities, and concave portions located between the convex portions, and a flat second layer, and further includes an absorbent core containing a superabsorbent polymer with a liquid permeation rate of 60 ml / min or more under a pressure of 2.0 kPa. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-153631 Summary of the Invention [Problem to be solved by the invention]

[0004] When worn, absorbent articles may be compressed by the wearer's skin. In particular, the topsheet of an absorbent article is directly affected by the wearer's body pressure, etc., and the convex portions formed on the topsheet may be crushed. When the convex portions are crushed, body fluids such as urine absorbed in the absorbent body are likely to return to the topsheet, which may cause "liquid return," in which the returned body fluids contaminate the skin. The above-mentioned patent documents do not disclose any technology for preventing such liquid return.

[0005] Therefore, the present invention relates to providing an absorbent article that can suppress the return of absorbed body fluid to the topsheet. [Means for solving the problem]

[0006] The present invention relates to an absorbent article comprising a topsheet and an absorbent body, having a vertical direction corresponding to the front-to-back direction of a wearer and a horizontal direction perpendicular to the vertical direction, and having a ventral side portion, a crotch portion and a back side portion along the vertical direction. It is preferable that the top sheet has an uneven structure. The topsheet preferably has a lower compressibility than the absorbent body, as calculated by the following formula: Compression ratio (%) = (Tb / Ta) x 100 Ta: The thickness of the absorbent article in a compressed state when the absorbent article is unfolded and a load of 3 kPa is applied. Tb: The thickness of the absorbent article before it is unfolded and placed under no pressure [Effects of the Invention]

[0007] The absorbent article of the present invention can prevent absorbed body fluid from returning to the topsheet. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an expanded plan view of one embodiment of the absorbent article of the present invention, schematically showing the skin-facing surface side (inner surface side) in an expanded and stretched state. [Figure 2] FIG. 2 is a cross-sectional view taken along the lateral direction of the absorbent main body shown in FIG. 1, showing the state before pressure is applied. [Figure 3] FIG. 3 is a cross-sectional view of the absorbent body shown in FIG. 2 in a pressurized state. [Figure 4] 1 is a drawing-substitute image showing one embodiment of a concave-convex sheet preferably used as a topsheet according to the present invention, and is an image taken from the first surface Z1 side. [Figure 5] Figure 5(A) is a partial cross-sectional view corresponding to the AA line portion of Figure 4, and Figure 5(B) is a partial cross-sectional view corresponding to the AA line portion of the uneven sheet shown in Figure 4 when the height of the horizontal ridge portions is uniform between the vertical ridge portions. [Figure 6]FIG. 5 is a partial cross-sectional view taken along the line BB in FIG. 4. [Figure 7] FIG. 5 is a partial cross-sectional view taken along the line CC in FIG. [Figure 8] FIG. 5 is a partial cross-sectional view taken along the line DD in FIG. 4. [Figure 9] 5 is an image taken from the second surface Z2 side of the embossed sheet shown in FIG. 4. [Figure 10] FIG. 10 is a partial cross-sectional view taken along the line EE in FIG. 9. [Figure 11] FIG. 10 is a partial cross-sectional view taken along the line FF in FIG. 9. [Figure 12] FIG. 10 is a partial cross-sectional view taken along the line GG in FIG. 9. [Figure 13] FIG. 10 is a partial cross-sectional view taken along the line HH in FIG. 9. [Figure 14] 14A and 14B are diagrams schematically illustrating an example of a preferred method for manufacturing the concave-convex sheet shown in Fig. 4. Fig. 14A is a top view showing the female support member, Fig. 14B is a top view showing the male support member, and Fig. 14C is a cross-sectional view illustrating the process of placing a fiber web on the male support member and pressing the female support member from above the fiber web into the male support member. [Figure 15] FIG. 15(A) is a top view showing the state in which the male support member is inserted into the female support member (however, the web is not shown), and FIG. 15(B) is a cross-sectional view of the above state. [Figure 16] 10 is a cross-sectional view showing a process in which the female support member is removed and hot air is blown from above the shaped fiber web to fuse the fibers together. FIG. [Figure 17] FIG. 17 is a cross-sectional view showing another embodiment of the topsheet according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0009] The absorbent article of the present invention will be described below based on preferred embodiments thereof. Figs. 1 to 3 show a flat-type disposable diaper (hereinafter, simply referred to as "diaper"), which is one embodiment of the absorbent article of the present invention. Fig. 1 shows the configuration of the diaper 1 as viewed from the skin-facing side. In its flat and stretched state, the diaper 1 shown in Fig. 1 has a longitudinal direction X, which corresponds to the front-to-back direction of a wearer and extends from the wearer's ventral side through the crotch region to the dorsal side, and a transverse direction Y perpendicular to the longitudinal direction X. The diaper 1 comprises a ventral region A, which is disposed on the wearer's ventral side when worn, a dorsal region B, which is disposed on the dorsal side, and a crotch region C, which is located between the ventral region A and the dorsal region B. The ventral region A, the crotch region C, and the dorsal region B are regions obtained by dividing the entire length of the diaper 1 in the longitudinal direction X into three equal parts, and extend continuously in the front-to-back direction of the wearer. The crotch portion C has an excretory region facing portion (not shown) that faces the excretory region of the wearer when the diaper 1 is worn. As shown in FIG. 1, the diaper 1 extends in a longitudinal direction X and is formed symmetrically with respect to a longitudinal centerline CL that divides the diaper 1 into two equal parts in a transverse direction Y.

[0010] In this specification, the "unfolded and stretched state" of the diaper 1 refers to the state in which the diaper 1 is unfolded and the elastic members of each part of the diaper 1 are stretched to the designed dimensions (the same dimensions as when the diaper 1 is unfolded flat with all influence of the elastic members eliminated). Furthermore, when focusing on a diaper or its constituent parts (e.g., absorbent body), the "skin-facing side" refers to the side that faces the wearer's skin when the diaper is worn, and the "non-skin-facing side" refers to the side that faces away from the wearer's skin when the diaper is worn. In other words, the skin-facing side is the side that is relatively close to the wearer's skin, and the non-skin-facing side is the side that is relatively far from the wearer's skin. "When worn" and "worn state" refer to the state in which the diaper is worn while maintaining the proper wearing position.

[0011] 1 and 2, the diaper 1 comprises a liquid-permeable topsheet 2 forming a skin-facing surface and a backsheet 3 forming a non-skin-facing surface. The backsheet 3 in this embodiment is a liquid-impermeable or water-repellent sheet. The absorbent body 4 is disposed between the topsheet 2 and the backsheet 3, and the topsheet 2, backsheet 3, and absorbent body 4 together constitute an absorbent main body 5. The topsheet 2 and backsheet 3 are each larger than the absorbent body 4 and extend outward from the outer peripheral edge of the absorbent body 4. The topsheet 2 and backsheet 3 extend outward in the transverse direction Y from both side edges of the absorbent body 4 along the longitudinal direction X (not shown). In this embodiment, both longitudinal end edges of the topsheet 2 and backsheet 3 substantially coincide with both longitudinal end edges of the diaper 1.

[0012] The topsheet 2 has an uneven structure. More specifically, the topsheet 2 has a plurality of convex portions and a plurality of concave portions formed on its surface. The topsheet 2 of this embodiment has an uneven structure in the area overlapping with the absorbent body 4, and convex portions and concave portions located between the convex portions are formed on the skin-facing side. Alternatively, the topsheet 2 may have an uneven structure over its entire area. Furthermore, the topsheet 2 may have an uneven structure on the skin-facing surface and a flat surface on the non-skin-facing surface, or conversely, the skin-facing surface may be flat and the non-skin-facing surface may have an uneven structure.

[0013] The topsheet 2 of this embodiment has an uneven shape on both the skin-facing and non-skin-facing sides, with the uneven shape on the skin-facing side corresponding to the uneven shape on the non-skin-facing side (see FIGS. 2 and 3). That is, the topsheet 2 of this embodiment has a first side (skin-facing side) and a second side (non-skin-facing side), and in the uneven structure of the topsheet 2, the first side has an uneven shape, and the second side has an uneven shape corresponding to the first side. In this case, the convex portions protruding on the first side (skin-facing side) of the topsheet 2 correspond, on their back side, to the concave portions on the second side (non-skin-facing side), and the convex portions protruding on the second side (non-skin-facing side) correspond, on their back side, to the concave portions on the first side (skin-facing side).

[0014] In order to make the convex portions of the uneven structure less susceptible to crushing, the height of the convex portions of the uneven structure of the top sheet 2 on the skin-facing side or non-skin-facing side is preferably 1.5 mm or more, more preferably 2.5 mm or more, even more preferably 3.0 mm or more, and preferably 5.0 mm or less, more preferably 4.5 mm or less, and also preferably 1.5 mm or more and 5.0 mm or less, more preferably 2.5 mm or more and 5.0 mm or less, even more preferably 3.0 mm or more and 4.5 mm or less. The height of the protrusions is the height from the top of the protrusions to the recesses in the thickness direction Z of the topsheet 2. When protrusions of different heights are formed on the topsheet 2, it is preferable that the height of the highest protrusion be within the above-mentioned range. The uneven structure of the topsheet 2 will be described in detail later.

[0015] The diaper 1 of this embodiment further comprises an outer nonwoven fabric 3a disposed on the non-skin-facing side of the backsheet 3 (see FIG. 2). The outer nonwoven fabric 3a forms the non-skin-facing side of the diaper 1. The outer nonwoven fabric 3a forms the outer shape of the diaper 1 in an unfolded and stretched state, and the peripheral edges of the outer nonwoven fabric 3a form the outlines of the ventral region A, the crotch region C, and the back region B.

[0016] As shown in Fig. 1, the diaper 1 of this embodiment is provided with a pair of leakage-preventing cuffs 6, 6 that overlap both side edges of the absorbent core 4 along the longitudinal direction X. The leakage-preventing cuffs 6 are made of water-repellent and breathable cuff-forming sheets 60. Near the free end of each leakage-preventing cuff 6, one or more thread-like cuff-forming elastic members 61 are arranged in a stretched state in the longitudinal direction X. When the diaper 1 is worn, the stretched cuff-forming elastic members 61 contract, causing the leakage-preventing cuffs 6 to stand up at least in the crotch region C, thereby preventing excrement such as urine from leaking outward in the transverse direction Y.

[0017] The exterior nonwoven fabric 3a extends outward in the transverse direction Y from both side edges of the absorbent body 4 along the longitudinal direction X, and forms side flap portions SF together with the cuff-forming sheets 60 that constitute the leakage-barrier cuffs 6. The side flap portions SF are portions made of members that extend outward in the transverse direction Y from both side edges of the absorbent body 4 along the longitudinal direction X. The side flap portions SF are made of at least the cuff-forming sheets 60 and the exterior nonwoven fabric 3a, and are configured including sheets that extend outward in the transverse direction Y from both side edges of the absorbent body 4 along the longitudinal direction X. The side flap portions SF of this embodiment are configured including the cuff-forming sheets 60, a topsheet 2, a backsheet 3, and the exterior nonwoven fabric 3a. The side flap portions SF are continuous from the ventral portion A through the crotch portion C to the back portion B, and extend outward in the lateral direction Y from both side edges of the absorbent body 4. The sheets constituting the side flap portions SF are joined to each other at the extending portions from the both side edges of the absorbent body 4 by known joining means such as adhesive, heat sealing, ultrasonic sealing, etc.

[0018] 1, in the diaper 1 of this embodiment, elastic members 63 (hereinafter also referred to as "leg elastic members 63") are arranged in a stretched state so as to extend in the longitudinal direction X through the crotch portion C of the diaper 1 on both sides along the longitudinal direction X of the diaper 1, specifically in each of the pair of side-flap portions SF, SF. Contraction of the leg elastic members 63 forms leg gathers in the left and right portions that are arranged around the legs of the wearer, i.e., on both sides in the longitudinal direction X of the diaper 1. In this embodiment, the leg elastic members 63 are fixed in a stretched state along the longitudinal direction X between the cuff-forming sheet 60 in the side-flap portion SF and the exterior nonwoven fabric 3a.

[0019] The diaper 1 of this embodiment has waist flaps WF extending outward in the longitudinal direction X from the edge of the absorbent body 4 in the back side portion B. The waist flaps WF are portions formed of members extending outward in the longitudinal direction X from the edge of the absorbent body 4 in the longitudinal direction X. In this embodiment, the waist flaps WF are composed of a cuff-forming sheet 60 extending outward in the longitudinal direction X from the edge of the absorbent body 4, a topsheet 2, a backsheet 3, and an exterior nonwoven fabric 3a. These sheets are joined together at their extensions from the edge of the absorbent body 4 by known joining means such as adhesive, heat sealing, or ultrasonic sealing. The waist flaps WF fit around the wearer's waist when the diaper 1 is worn. The waist flap portion WF may have elastic members extending in the lateral direction Y arranged in a stretched state, so that waist gathers are formed by contraction of the elastic members.

[0020] The diaper 1 of this embodiment includes a pair of fastening members located on both side edges of the back-side portion B along the longitudinal direction X and extending from the both side edges in the transverse direction Y. Each fastening member includes a side panel 7 extending outward in the transverse direction Y from each of the both side edges of the side flap portion SF in the back-side portion B, and a fastening tape 8 fixed to the leading end of the side panel 7 in the extending direction so as to further extend outward in the transverse direction Y.

[0021] The side panel 7 is composed of two rectangular panel materials in a plan view and a plurality of elastic members fixed in a stretched state between the two panel materials and extending in the lateral direction Y (not shown). The plurality of elastic members provided on the side panel 7 are arranged at predetermined intervals in the longitudinal direction X and form a stretchable portion that is stretchable in the lateral direction Y, which is the stretching direction of the elastic members. In other words, the side panel 7 is stretchable in the lateral direction Y. The inner side edge of the side panel 7 in the lateral direction Y is fixed between the sheets that form the side flap portion SF (for example, between the cuff-forming sheet 60 and the exterior nonwoven fabric 3a) by a known joining means such as an adhesive.

[0022] The fastening tape 8 is composed of a tape base material and a fastening portion, and the tape base material forms the outer shape of the fastening tape 8. In the fastening tape 8, the fastening portion is disposed on the skin-facing surface of the tape base material. By removably fastening the tape base material to a fastening region described below, the fastening tape 8 can be removably fastened to the fastening region. The fastening tape 8 has a rectangular shape in a plan view, and its inner side edge in the lateral direction Y is fixed to the non-skin-facing surface of the tip of the side panel 7 by a known joining means such as an adhesive.

[0023] The abdominal portion A of the diaper 1 is provided with a fastening region (not shown) to which the fastening portion of the fastening tape 8 can be removably fastened. The fastening region is made of an appropriate material depending on the material of the fastening portion of the fastening tape 8. For example, if the fastening portion is a male member of a mechanical fastener, the fastening region may be made of a fiber sheet, such as a knitted fabric or a nonwoven fabric, that is engageable with the male member of the mechanical fastener. If the fastening portion is made of an adhesive, the fastening region may be made of, for example, a smooth film made of synthetic resin. In this embodiment, the outer nonwoven fabric 3a that forms the non-skin-facing surface of the abdominal portion A of the diaper 1 serves as the fastening region.

[0024] The diaper 1 of this embodiment is provided with a pair of abdominal flaps 67, 67 extending outward in the lateral direction Y from both side edges of the side flap portion SF in the abdominal portion A along the longitudinal direction X. The abdominal flaps 67 are made of a non-stretchable sheet material, and like the side panels 7, their inner side edges in the lateral direction Y are fixed between the sheets forming the side flap portion SF (for example, between the cuff-forming sheet 60 and the exterior nonwoven fabric 3a) by a known joining means such as an adhesive. When putting on a diaper 1 having ventral flaps 67, the diaper 1 is passed below the wearer's crotch area, and by grasping one of the ventral flaps 67 with one hand and grasping the dorsal part B with the other hand, the diaper 1 can be easily pulled up toward the wearer (towards the crotch area) and each part of the diaper can be easily applied to each part of the wearer's waist and crotch area.

[0025] As shown in Figures 1 and 2, the diaper 1 includes a liquid-retaining absorbent body 4. The absorbent body 4 shown in Figure 1 is substantially rectangular and is arranged so that its longitudinal direction coincides with the longitudinal direction X of the diaper. As shown in Figure 1, the absorbent body 4 of this embodiment is continuous from the ventral portion A through the crotch portion C to the dorsal portion B. Specifically, both an upper-layer absorbent body 41 and a lower-layer absorbent body 43, which will be described later, are continuous from the ventral portion A through the crotch portion C to the dorsal portion B. In this embodiment, the absorbent body 4 has both side edges extending linearly along the longitudinal direction X. Alternatively, the absorbent body 4 may have a narrowed portion in the crotch portion C in the transverse direction Y. In this case, both longitudinal edge portions of the absorbent body 4 are located inward of both longitudinal edge portions of the diaper 1.

[0026] The absorbent core 4 of this embodiment has an upper absorbent core 41 and a lower absorbent core 43. In the thickness direction Z of the diaper 1, the upper absorbent core 41 is disposed closer to the skin side than the lower absorbent core 43. The absorbent core 4 of this embodiment has a two-layer structure consisting of the upper absorbent core 41 and the lower absorbent core 43. The upper absorbent body 41 and the lower absorbent body 43 each include an absorbent core 41a, 43a having an absorbing performance. The absorbent cores 41a, 43a are the main liquid-absorbing parts of the diaper 1 and are made of a water-absorbent material such as pulp or a water-absorbent polymer. The upper absorbent body 41 and the lower absorbent body 43 may each be formed by covering an absorbent core 41a, 43a with a liquid-permeable core wrap sheet, or may not include the core wrap sheet. Furthermore, the absorbent body 4 may be such that the upper absorbent body 41 includes the absorbent core 41a and a core wrap sheet covering it, and the lower absorbent body 43 consists only of the absorbent core 43a, or the upper absorbent body 41 includes the absorbent core 41a only, and the lower absorbent body 43 includes the absorbent core 43a and a core wrap sheet covering it.

[0027] The absorbent body 4 of this embodiment comprises a laminate consisting of two layers of upper and lower absorbent cores 41a, 43a, and the skin-facing and non-skin-facing surfaces of the laminate are each covered with a core wrap sheet 45. In this case, the core wrap sheet 45 on the skin-facing side of the laminate and the upper absorbent core 41a form the upper-layer absorbent body 41, and the core wrap sheet 45 on the non-skin-facing side of the laminate and the lower absorbent core 43a form the lower-layer absorbent body 43. In this way, the absorbent body 4 may have both the absorbent cores 41a, 43a of the upper-layer absorbent body 41 and the lower-layer absorbent body 43 collectively covered by the core wrap sheet 45. Specifically, the surface of the laminate in which the absorbent cores 41a and 43a are stacked is covered with a single core wrap sheet 45, and the core wrap sheet 45 covers the skin-facing surface of the absorbent core 41a of the upper absorbent body 41 and the non-skin-facing surface of the absorbent core 43a of the lower absorbent body 43 (see Figure 2).

[0028] The topsheet 2 has a lower compressibility, calculated by the following formula, than the absorbent core 4. "Unfolding the diaper 1" means that the diaper 1 is unfolded and stretched as shown in Figure 1. Furthermore, the "3 kPa" pressure of the diaper 1 corresponds to the load applied to the diaper 1 when worn. Compression ratio (%) = (Tb / Ta) x 100 Ta: Thickness (mm) of the diaper 1 when it is unfolded and a load of 3 kPa is applied Tb: Thickness of the diaper 1 before pressure application (mm)

[0029] More specifically, when the compression ratio calculated from the thickness T4 of the absorbent body 4 in the diaper 1 before or in a pressurized state is compared with the compression ratio calculated from the thickness T3 of the topsheet 2 in the diaper 1 before or in a pressurized state, the compression ratio of the topsheet 2 is lower than the compression ratio of the absorbent body 4. The higher the compression ratio, the more easily the diaper 1 collapses under pressure, and the lower the compression ratio, the more difficult it is to collapse under pressure.

[0030] [Method for measuring compression ratio] First, the diaper 1 is unfolded and stretched, and then cut along the transverse direction Y at the crotch region C. Next, the cut diaper 1 is placed with the skin-facing side facing upward, and the cut surface of the diaper 1 is magnified and observed under no load using a microscope (Keyence Corporation's Digital Microscope VHX-1000), and the thicknesses of the absorbent core 4 and topsheet 2 at the cut surface are measured. Measurements are taken at any five points on the cut surface, and the average of these values ​​is taken as the thickness (Tb) of the absorbent core 4 or topsheet 2 before pressure application. The thickness of the topsheet 2 before pressure application is measured at a portion where the convex portions of the concavo-convex structure are not crushed. Next, a weight (contact area with the diaper 1: 7 cm × 7 cm) is placed on the skin-facing surface of the cut diaper 1, and a load of 3 kPa is applied to place it under pressure. The cut surface of the diaper 1 is then magnified and observed using a microscope, and the thicknesses of the absorbent core 4 and topsheet 2 at the cut surface are measured. This measurement is also performed at five arbitrary points on the cut surface, and the average of these values ​​is taken as the thickness (Ta) of the absorbent core 4 or topsheet 2 under pressure. Note that, if fluffing affects the thickness, it is preferable to measure under a low load of 0.05 kPa to minimize this effect. A laser displacement meter may be used instead of image observation.

[0031] When the absorbent body 4 is configured to include an upper absorbent body 41 and a lower absorbent body 43, the total thickness T4 of the upper absorbent body 41 and the lower absorbent body 43 (see FIGS. 2 and 3) is measured. The thickness T1 of the upper absorbent body 41 (see Figures 2 and 3) is the thickness of the entire upper absorbent body 41. When the upper absorbent body 41 includes a core wrap sheet, the thickness of the upper absorbent body 41 is the total thickness of the absorbent core provided in the upper absorbent body 41 and the core wrap sheets on the skin-facing side and non-skin-facing side of the absorbent core. The thickness T2 of the lower absorbent body 43 (see Figures 2 and 3) is the overall thickness of the lower absorbent body 43. When the lower absorbent body 43 includes a core wrap sheet, the thickness of the lower absorbent body 43 is the total thickness of the absorbent core provided in the lower absorbent body 43 and the core wrap sheets on the skin-facing and non-skin-facing sides of the absorbent core. As in this embodiment, when the surfaces of the laminate of both the absorbent cores 41a, 43a of the upper absorbent body 41 and the lower absorbent body 43 are covered with a core wrap sheet 45, the thickness of the upper absorbent body 41 is the total thickness of the absorbent core 41a provided in the upper absorbent body 41 and the core wrap sheet 45 on the skin-facing side of the absorbent core 41a, and the thickness of the lower absorbent body 43 is the total thickness of the absorbent core 43a provided in the lower absorbent body 43 and the core wrap sheet 45 on the non-skin-facing side of the absorbent core 43a.

[0032] The core wrap sheet covering the non-skin-facing surface of the upper absorbent core and the core wrap sheet covering the skin-facing surface of the lower absorbent core may be in direct contact with each other, or a liquid-permeable intermediate sheet (not shown) may be interposed between these two core wrap sheets. When an intermediate sheet is interposed, the thickness of the upper absorbent body 41 is the thickness including the thickness of the intermediate sheet. Examples of the intermediate sheet include fiber sheets made of single-layer or multi-layer nonwoven fabric, paper, laminates of these, etc. The intermediate sheet may also be a mesh sheet, woven fabric, etc.

[0033] The thickness T3 of the topsheet 2 (see Figures 2 and 3) is the maximum thickness of the topsheet 2. For example, in the topsheet 2 of this embodiment, the thickness of the topsheet 2 is the distance in the thickness direction Z between the apex of the convex portions protruding toward the skin-facing surface and the apex of the convex portions protruding toward the non-skin-facing surface. A second sheet (not shown) made of nonwoven fabric or paper, also called a sublayer sheet, may be disposed between the topsheet 2 and the absorbent body 4, for example, between the topsheet 2 and the upper absorbent body 41. When another liquid-permeable sheet such as a second sheet is disposed between the topsheet 2 and the absorbent body 4, the thickness of the topsheet 2 is the thickness including the thickness of the other sheet.

[0034] In the diaper 1 of this embodiment, the compressibility of the topsheet 2 is lower than that of the absorbent body 4, so that the topsheet 2 is less likely to collapse than the absorbent body 4 when worn. As a result, even when the diaper 1 is pressurized by the wearer's body pressure or the like, the absorbent body 4 collapses first, making it easier to secure a gap between the wearer's skin and the diaper 1 and stably maintaining the uneven structure of the topsheet 2 (see FIG. 3). Furthermore, the collapse of the absorbent body 4 due to pressure enhances the liquid diffusibility within the absorbent body 4. In this way, the uneven structure of the topsheet 2 is maintained and the liquid diffusibility of the absorbent body 4 is enhanced, making it more difficult for body fluids such as urine absorbed by the absorbent body 4 to transfer to the topsheet 2, effectively suppressing liquid return.

[0035] The compression ratios of the topsheet 2 and the absorbent body 4 can be adjusted by the basis weight of the pulp in the absorbent core of the absorbent body 4 , the basis weight of the topsheet 2 , and the uneven structure of the topsheet 2 .

[0036] In order to ensure the above-mentioned effects, it is preferable that the compression ratios of the absorbent body 4 and the topsheet 2 are within the following ranges. The ratio of the compressibility of the top sheet 2 to the compressibility of the absorbent body 4 (top sheet / absorbent body) is preferably 0.50 or more, more preferably 0.60 or more, and preferably 0.95 or less, more preferably 0.90 or less, and also preferably 0.50 or more and 0.95 or less, more preferably 0.60 or more and 0.90 or less. The compression ratio of the top sheet 2 is preferably greater than 100%, more preferably 110% or greater, and preferably 250% or less, more preferably 220% or less, and also preferably greater than 100% and 250% or less, more preferably 110% or greater and 220% or less. The compressibility of the absorbent body 4 is preferably 120% or more, more preferably 150% or more, and is preferably 450% or less, more preferably 400% or less, and is also preferably 120% or more and 450% or less, more preferably 150% or more and 400% or less.

[0037] From the viewpoint of further suppressing liquid return, it is preferable that the thickness of the topsheet 2 before pressure application is smaller than that of the absorbent body 4, and that the thickness of the topsheet 2 in a pressurized state is smaller than that of the absorbent body 4. With this configuration, the uneven structure of the topsheet 2 in a pressurized state can be more stably maintained, and the liquid diffusibility of the absorbent body 4 can be further improved. To achieve a better balance between the stability of the concave-convex structure of the topsheet 2 under pressure and the liquid diffusibility of the absorbent body 4, the thicknesses of the topsheet 2 and the absorbent body 4 are preferably within the following ranges. The ratio of the thickness T4 of the absorbent body 4 before pressure application (see Figure 2) to the thickness T3 of the top sheet 2 before pressure application (see Figure 2) (T4 before pressure application / T3 before pressure application) is preferably 1.20 or more, more preferably 1.40 or more, and preferably 4.00 or less, more preferably 3.00 or less, even more preferably 2.80 or less, and is also preferably 1.20 or more and 4.00 or less, more preferably 1.20 or more and 3.00 or less, even more preferably 1.40 or more and 2.80 or less. The thickness T4 (see Figure 2) of the absorbent body 4 before pressure application is preferably 2.5 mm or more, more preferably 3.0 mm or more, and preferably 6.0 mm or less, more preferably 5.5 mm or less, and also preferably 2.5 mm or more and 6.0 mm or less, more preferably 3.0 mm or more and 5.5 mm or less. The thickness T4 of the absorbent body 4 in a pressurized state (see Figure 3) is preferably 0.7 mm or more, more preferably 0.9 mm or more, and preferably 5.5 mm or less, more preferably 5.0 mm or less, and also preferably 0.7 mm or more and 5.5 mm or less, more preferably 0.9 mm or more and 5.0 mm or less.

[0038] As described above, the absorbent body 4 of this embodiment has an upper absorbent body 41 and a lower absorbent body 43. In this case, the upper absorbent body 41 and the lower absorbent body 43 may have the same or different compression ratios.

[0039] From the viewpoint of further suppressing liquid return, it is preferable that the topsheet 2 has a lower compression ratio than the upper-layer absorbent body 41. In other words, it is preferable that the topsheet 2 is less likely to be crushed than the upper-layer absorbent body 41. In this case, it is preferable that the compression ratios of the upper-layer absorbent body 41 and the topsheet 2 are each within the following ranges. The ratio of the compression rate of the upper absorbent body 41 to the compression rate of the top sheet 2 (upper absorbent body / top sheet) is preferably greater than 1.00, more preferably 1.10 or more, and preferably 2.00 or less, more preferably 1.50 or less, and also preferably greater than 1.00 and 2.00 or less, more preferably 1.10 or more and 1.50 or less. The compression ratio of the upper absorbent body 41 is preferably 150% or more, more preferably 180% or more, even more preferably 200% or more, and is preferably 500% or less, more preferably 450% or less, and also preferably 150% or more and 500% or less, more preferably 180% or more and 450% or less, even more preferably 200% or more and 450% or less.

[0040] From the viewpoint of further suppressing liquid return, it is preferable that the thickness of the topsheet 2 before and after pressure application is smaller than that of the upper-layer absorbent body 41. In other words, it is preferable that the thickness of the upper-layer absorbent body 41 before and after pressure application is greater than the thickness of the topsheet 2. With this configuration, the uneven structure of the topsheet 2 in the pressurized state can be more stably maintained, and the liquid diffusibility of the upper-layer absorbent body 41 can be further improved.

[0041] To achieve a better balance between the stability of the concave-convex structure of the topsheet 2 under pressure and the liquid diffusibility of the upper absorbent body 41, the thicknesses of the topsheet 2 and the upper absorbent body 41 are preferably within the following ranges. The ratio of the thickness T1 of the upper absorbent body 41 before compression (see Figure 2) to the thickness T3 of the top sheet 2 before compression (see Figure 2) (T1 before compression / T3 before compression) is preferably 1.10 or more, more preferably 1.30 or more, and preferably 2.90 or less, more preferably 2.70 or less, and also preferably 1.10 or more and 2.90 or less, more preferably 1.30 or more and 2.70 or less. The thickness T1 (see Figure 2) of the upper absorbent body 41 before pressurization is preferably 2.0 mm or more, more preferably 3.0 mm or more, and preferably 5.0 mm or less, more preferably 4.8 mm or less, and also preferably 2.0 mm or more and 5.0 mm or less, more preferably 3.0 mm or more and 4.8 mm or less. The thickness T1 (see Figure 3) of the upper absorbent body 41 in a pressurized state is preferably 0.5 mm or more, more preferably 0.7 mm or more, and preferably 4.0 mm or less, more preferably 3.5 mm or less, and also preferably 0.5 mm or more and 4.0 mm or less, more preferably 0.7 mm or more and 3.5 mm or less.

[0042] When the absorbent body 4 has an upper absorbent body 41 and a lower absorbent body 43, it is preferable that the compressibility satisfy the magnitude relationship (1) below. With such a configuration, bodily fluids in the absorbent body 4 can be transferred more to the non-skin-facing side (the lower absorbent body 43 side), thereby further suppressing fluid return. Upper absorbent body 41 > surface sheet 2 > lower absorbent body 43 (1)

[0043] In order to ensure the above-mentioned effects, the ratio of the compression rate of the lower absorbent body 43 to the compression rate of the top sheet 2 (lower absorbent body / top sheet) is preferably 0.40 or more, more preferably 0.50 or more, and preferably 0.90 or less, more preferably 0.80 or less, and also preferably 0.40 or more and 0.90 or less, more preferably 0.50 or more and 0.80 or less. The compression ratio of the lower absorbent body 43 is preferably 120% or more, more preferably 130% or more, and preferably 200% or less, more preferably 190% or less, and also preferably 120% or more and 200% or less, more preferably 130% or more and 190% or less.

[0044] When the absorbent body 4 has an upper absorbent body 41 and a lower absorbent body 43, it is preferable that the thickness before pressure satisfies the following relationship (2). With such a configuration, the relationship (1) is more likely to be satisfied, and liquid return can be further suppressed. Upper absorbent body 41 > surface sheet 2 > lower absorbent body 43 (2)

[0045] When the absorbent body 4 has an upper absorbent body 41 and a lower absorbent body 43, it is preferable that the thickness in a pressurized state satisfies the following relationship (3). With such a configuration, the relationship (1) is more likely to be satisfied, and liquid return can be further suppressed. Upper absorbent body 41 > surface sheet 2 > lower absorbent body 43 (3)

[0046] From the viewpoint of more easily satisfying either or both of the magnitude relationships (2) and (3), the thickness of the lower absorbent body 43 before pressurization is preferably within the following range. The thickness T2 of the lower absorbent body 43 before compression (see Figure 2) is preferably 0.20 or more, more preferably 0.30 or more, and preferably 0.80 or less, more preferably 0.60 or less, relative to the thickness T3 of the top sheet 2 before compression (see Figure 2) (T2 before compression / T3 before compression). Also, the ratio is preferably 0.20 or more and 0.80 or less, more preferably 0.30 or more and 0.60 or less. The thickness T2 (see Figure 2) of the lower absorbent body 43 before pressurization is preferably 0.4 mm or more, more preferably 0.5 mm or more, and preferably 4.0 mm or less, more preferably 3.5 mm or less, and also preferably 0.4 mm or more and 4.0 mm or less, more preferably 0.5 mm or more and 3.5 mm or less. The thickness T2 (see Figure 3) of the lower absorbent body 43 in a pressurized state is preferably 0.3 mm or more, more preferably 0.4 mm or more, and preferably 3.5 mm or less, more preferably 3.0 mm or less, and also preferably 0.3 mm or more and 3.5 mm or less, more preferably 0.4 mm or more and 3.0 mm or less.

[0047] From the viewpoint of more easily satisfying the magnitude relationship (1) above and further suppressing liquid return, it is preferable that the absorbent core of the upper-layer absorbent body 41 is configured to contain pulp and a water-absorbent polymer. For example, it is preferable that the absorbent core of the upper-layer absorbent body 41 is a mixed stack containing a water-absorbent polymer and pulp. In this case, it is preferable that the upper-layer absorbent body 41 includes a core wrap sheet that covers the surface of the absorbent core made of the mixed stack.

[0048] The pulp constituting the absorbent core can be plant-derived pulp, recycled pulp, etc. Examples of plant-derived pulp include wood pulp such as softwood pulp and hardwood pulp, cotton pulp such as cotton linter and cotton lint, and non-wood pulp such as straw pulp and bagasse pulp. It is preferable to use defibrated fluff pulp as the pulp.

[0049] The absorbent polymer constituting the absorbent core is composed of various hydrogel materials, such as crosslinked polymers or copolymers of acrylic acid or alkali metal acrylates, crosslinked polyacrylic acid and its salts and polyacrylate graft polymers, crosslinked starch or carboxymethyl cellulose, crosslinked starch-acrylate graft copolymer hydrolysis products, crosslinked vinyl alcohol-acrylate copolymers, crosslinked maleic anhydride graft polyvinyl alcohol, crosslinked isobutylene-maleic anhydride copolymers, saponified vinyl acetate-acrylic acid ester copolymers, etc., and one of these components can be used alone or in combination of two or more. The shape of the absorbent polymer particles can be, for example, spherical, lumpy, bale-shaped, or irregular.

[0050] From the viewpoint of further improving the body fluid retention in the absorbent body 4 and further suppressing liquid return, it is preferable that the absorbent core of the lower-layer absorbent body 43 is mainly composed of a water-absorbent polymer. "Mainly composed of a water-absorbent polymer" means that the content of water-absorbent polymer in the absorbent core is more than 50% by mass. In this case, for example, the absorbent core of the lower-layer absorbent body 43 is preferably a polymer sheet having a structure in which a water-absorbent polymer is supported between two sheets. Also, it is preferably a laminate of a core wrap sheet and a deposit of a water-absorbent polymer, or a laminate of a core wrap sheet and a dried mixture containing a water-absorbent polymer. The dried mixture can be obtained, for example, by drying a liquid mixture containing a water-absorbent polymer and a water-soluble polymer.

[0051] From the viewpoint of more easily satisfying the size relationship (1) above and further suppressing liquid return, it is preferable that the basis weight of the pulp constituting the absorbent core of the upper-layer absorbent body 41 is higher than that of the lower-layer absorbent body 43. In the diaper 1, it is preferable that the basis weight of the pulp of the absorbent core is satisfied at least in the crotch region C, and more preferably in the back region B, the crotch region C, and the abdominal region A. The "basis weight of the pulp constituting the absorbent core" does not include the basis weight of pulp sheets such as nonwoven fabrics and backing paper.

[0052] Hereinafter, the basis weight of the pulp constituting the absorbent core 41a in the upper-layer absorbent body 41 will also be referred to as the "upper-layer core pulp basis weight," and the basis weight of the pulp constituting the absorbent core 43a in the lower-layer absorbent body 43 will also be referred to as the "lower-layer core pulp basis weight." From the same viewpoint of more easily satisfying the magnitude relationship (1) above and further suppressing liquid return, it is preferable that the upper-layer core pulp basis weight and the lower-layer core pulp basis weight be within the following ranges. When the lower absorbent core 43a contains pulp, the ratio of the upper core pulp basis weight to the lower core pulp basis weight (upper absorbent / lower absorbent) is preferably 3.0 or more, more preferably 5.0 or more, and preferably 12.0 or less, more preferably 15.0 or less, and preferably 3.0 or more and 15.0 or less, more preferably 5.0 or more and 12.0 or less. The basis weight of the upper layer core pulp is preferably 70 g / m 2 More preferably, 80 g / m 2 or more, and preferably 170 g / m 2 or less, more preferably 160 g / m 2 and preferably 70 g / m 2More than 170g / m 2 Less than 80 g / m 2 More than 160g / m 2 The following is the result. The basis weight of the lower layer core pulp is preferably 0 g / m 2 More preferably, 10 g / m 2 or more, and preferably 100 g / m 2 Less than 80 g / m 2 or less, and preferably 0 g / m 2 More than 100g / m 2 Less than 10 g / m, more preferably 2 More than 80g / m 2 The following is the result.

[0053] From the viewpoint of further improving the bodily fluid retention of the absorbent body 4, it is preferable that the water-absorbent polymer constituting the absorbent core of the upper-layer absorbent body 41 has a higher basis weight than that of the lower-layer absorbent body 43. Hereinafter, the basis weight of the absorbent polymer constituting the absorbent core 41a in the upper-layer absorbent body 41 will also be referred to as the "upper-layer core SAP basis weight," and the basis weight of the absorbent polymer constituting the absorbent core 43a in the lower-layer absorbent body 43 will also be referred to as the "lower-layer core SAP basis weight." From the perspective of further improving the body fluid retention ability of the absorbent body 4, the upper-layer core SAP basis weight and the lower-layer core SAP basis weight are preferably within the following ranges. The ratio of the SAP basis weight of the lower core to the SAP basis weight of the upper core (lower absorbent / upper absorbent) is preferably 0.40 or more, more preferably 0.50 or more, and preferably 0.90 or less, more preferably 0.80 or less, and also preferably 0.40 or more and 0.90 or less, more preferably 0.50 or more and 0.80 or less. The basis weight of the upper core SAP is preferably 100 g / m 2 More preferably, 120 g / m 2 or more, preferably 300 g / m 2 or less, more preferably 280 g / m 2 and preferably 100 g / m 2 More than 300g / m 2 or less, more preferably 120 g / m 2 More than 280g / m2 The following is the result. The basis weight of the lower core SAP is preferably 80 g / m 2 More preferably, 100 g / m 2 or more, preferably 200 g / m 2 or less, more preferably 180 g / m 2 and preferably 80 g / m 2 More than 200g / m 2 or less, more preferably 100 g / m 2 More than 180g / m 2 The following is the result.

[0054] [Method for measuring the basis weight of each pulp or water-absorbent polymer constituting the absorbent core] The upper absorbent body 41 and the lower absorbent body 43 are removed from the absorbent body, and the absorbent core is then removed and the mass of the absorbent core is measured. Next, the water-absorbent polymer and the fibrous material (pulp) of each absorbent core are separated, and the mass of each of the water-absorbent polymer and the fibrous material is measured. The water-absorbent polymer and the fibrous material can be separated by any method that can almost completely separate them, without any particular restrictions. For example, the difference in particle size can be exploited by sieving through a fine mesh, or the difference in mass can be exploited by placing the absorbent core in an airflow that scatters only the pulp, and measuring the mass before and after scattering. Alternatively, each absorbent core can be immersed in an ascorbic acid solution and exposed to sunlight to dissolve the water-absorbent polymer, and the mass of the remaining fiber after washing can be determined, and the mass of the remaining fiber after washing can be calculated by subtracting the mass of the remaining fiber after washing from the mass of the cut-out absorbent core. To distinguish the separated fiber material (pulp) from other fiber types, and to analyze the mass and content ratio of the identified fibers, JIS L 1030-1 (Part 1 Fiber Identification) and JIS The standard of L 1030-2 (Part 2: Test method for blending ratio of textile products) can be used as appropriate.

[0055] The materials forming each part of the diaper in the above-described embodiment will now be described in detail. The topsheet 2, backsheet 3 and absorbent core 4 may be made of any material conventionally used in absorbent articles, without any particular restrictions. The top sheet 2 can be, for example, a liquid-permeable nonwoven fabric. From the viewpoint of easily providing a concave-convex structure, the top sheet 2 is preferably a nonwoven fabric containing thermoplastic fibers. Examples of the constituent resin (thermoplastic resin) of the thermoplastic fibers include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate; polyamides such as nylon 6 and nylon 66; polyacrylic acid, polymethacrylic acid alkyl esters, polyvinyl chloride, polyvinylidene chloride, etc., and these can be used alone or in combination of two or more. The thermoplastic fibers may also be composite fibers such as core-sheath type or side-by-side type. The composite fibers may be composed of multiple resin components.

[0056] To better maintain the concave-convex structure of the topsheet 2, the fineness of the constituent fibers of the topsheet 2 is preferably 1.0 dtex or more and 3.0 dtex or less, and more preferably 1.2 dtex or more and 2.5 dtex or less. The fineness is measured by the following method.

[0057] [Method for measuring fiber fineness] Surface sheet 2 to be measured, 50mm x 100mm (area 5000mm 2 ) to prepare a measurement sample. Next, the measurement sample is viewed in cross section, and the fiber thickness of 10 standard fibers at positions spaced 0.05 mm apart from the non-skin-facing surface of the measurement sample in the thickness direction is measured using an electron microscope, and the average fiber thickness Dn (μm) is calculated. Next, the constituent resin of the standard fiber at positions spaced 0.2 mm apart from the skin-facing surface in the thickness direction is identified, and the theoretical fiber density Pn (g / cm) is calculated using a differential scanning calorimeter (DSC). 3 The obtained average fiber thickness Dn (μm) and theoretical fiber density Pn (g / cm 3 ) is used to calculate the weight (g) per 10,000 m of fiber length, and this calculated value is taken as the fineness (dtex) of the constituent fibers of the topsheet 2.

[0058] The backsheet 3 can be made of a liquid-impermeable resin film or a laminate of a resin film and a nonwoven fabric. The absorbent body 4 can be made of an absorbent core made of an aggregate of hydrophilic fibers such as wood pulp or hydrophilically treated synthetic fibers, or an aggregate made of such fibers with a water-absorbent polymer. The cuff-forming sheet 60 can be made of a water-repellent nonwoven fabric. When the upper absorbent body 41 or the lower absorbent body 43 is provided with a core wrap sheet, various types of paper and nonwoven fabric can be used as the core wrap sheet.

[0059] The exterior nonwoven fabric 3a can be, for example, a nonwoven fabric made by various methods, such as a spunbond nonwoven fabric, an air-through nonwoven fabric, a spunlace nonwoven fabric, a heat-rolled nonwoven fabric, a melt-blown nonwoven fabric, or a laminated nonwoven fabric of these. The exterior nonwoven fabric 3a may be made of a single sheet as shown in Fig. 2, or alternatively, it may be made of a laminate of multiple sheets.

[0060] The elastic members of the diaper 1, specifically the cuff-forming elastic members 61, leg elastic members 63, etc., may be made of various known elastic materials commonly used in absorbent articles of this type, without any particular restrictions. Examples of elastic materials include synthetic rubbers such as styrene-butadiene, butadiene, isoprene, and neoprene, natural rubber, EVA, stretchable polyolefins, and polyurethanes. The elastic members may preferably be in the form of threads (such as rubber threads) or strings (such as flat rubber) with a rectangular, square, circular, or polygonal cross section, or multifilament threads. The elastic members provided on the side panels 7 can also be made of the above-mentioned elastic materials.

[0061] Next, the uneven sheet 10 having an uneven structure, which is preferably used for the topsheet 2 according to the present invention, will be described based on a preferred embodiment thereof. The uneven sheet 10 shown in Figures 4 and 9 is a nonwoven fabric with an uneven structure, and has a first surface Z1 and a second surface Z2 opposite the first surface Z1. When the first surface Z1 of the uneven sheet 10 is viewed in plan, the first surface Z1 side is formed with a plurality of vertical rib portions 11 protruding in the thickness direction of the uneven sheet 10 and a plurality of horizontal rib portions 21 arranged to connect the vertical rib portions 11, 11. The vertical rib portions 11 extend in one direction (hereinafter also referred to as the "Y1 direction") in plan view and are arranged side by side at a distance in the X1 direction perpendicular to the Y1 direction. The horizontal rib portions 21 extend in the X1 direction, and adjacent horizontal rib portions 21 on either side of the vertical rib portion 11 are arranged in a straight line, so that the horizontal rib portions 21 connect the vertical rib portions 11, 11. The width centerlines of adjacent horizontal rib portions 21 sandwiching a vertical rib portion 11 lie within the width range of the adjacent horizontal rib portion 21. That is, the width centerlines of adjacent horizontal rib portions 21 sandwiching a vertical rib portion 11 are positioned approximately in the same position in the Y1 direction, with the deviation in position in the Y1 direction being within, for example, 5 mm. The area surrounded by the vertical rib portion 11 and the horizontal rib portion 21 forms a valley portion 14 recessed from the first surface Z1 side toward the second surface Z2 side.

[0062] The uneven sheet 10 has a lattice-like uneven surface on the first surface (Z1) side, which is formed by the vertical rib portions 11 and horizontal rib portions 21. The term "lattice-like" here refers to the vertical rib portions 11 and horizontal rib portions 21 forming a shape with lattice points and edges in a plan view, and includes various lattice shapes, such as a square lattice, a triangular lattice, and a hexagonal lattice. When the X1 direction and the Y1 direction on the first surface (Z1) side are orthogonal to each other, the rib portions formed by the vertical rib portions 11 and the horizontal rib portions 21 are arranged in an orthogonal lattice pattern when viewed from the first surface (Z1) side. Because the rib portions 11 and 21 are arranged in a lattice pattern, when a load is applied to the uneven sheet 10 from the first surface (Z1) side, the load applied to the vertical rib portions 11 can be distributed to the horizontal rib portions 21. Therefore, when the uneven sheet 10 is used as the topsheet 2, excellent cushioning properties are achieved. In order to obtain such cushioning properties, the embossed sheet 10 of this embodiment may be used with the first surface Z1 side facing the skin.

[0063] The vertical ridge portions 11 have the same height along one direction (Y1 direction). This "same height" means that the height is within a range of 0.9 to 1.1 times the average measurement value. As shown in Figures 5 and 6, the vertical rib portion 11 is divided into a top region 11T and a wall portion 11W in the thickness direction of the uneven sheet 10, and the top region 11T extends in one direction (Y1 direction) at the same height. The top region 11T forms the outer surface fiber layer on the first surface Z1 side. The wall portion 11W extends in the thickness direction from the top region 11T toward the second surface Z2 side. As shown in Figure 7, the vertical rib portion 11 has an internal space 12 extending in one direction (Y1 direction) inside the rib portion 11.

[0064] As shown in Figure 8, the horizontal rib portion 21 is divided into a top region 21T and a wall portion 21W in the thickness direction of the uneven sheet 10. The top region 21T is located on the first surface Z1 side, and the wall portion 21W extends from the top region 21T in the thickness direction toward the second surface Z2 side. The horizontal rib portion 21 has an internal space 22. The internal space 22 of the horizontal rib portion 21 and the internal space 12 of the vertical rib portion 11 are in communication with each other on the second surface Z2 side.

[0065] In the concave-convex sheet 10, the Y1 direction on the first surface Z1 side corresponds to the Y1 direction on the second surface Z2 side, and the X1 direction on the first surface Z1 side corresponds to the X1 direction on the second surface Z2 side. That is, the Y1 direction on the first surface Z1 side and the Y1 direction on the second surface Z2 side coincide with each other, and the X1 direction on the first surface Z1 side and the X1 direction on the second surface Z2 side coincide with each other.

[0066] On the second surface Z2 side of the uneven sheet 10, as shown in FIGS. 9 and 12, multiple convex rib portions 31 extend in the Y1 direction on the second surface Z2 side in a plan view and are arranged side by side at a distance in the X1 direction perpendicular to the Y1 direction. Furthermore, a concave rib portion 36 sandwiched between adjacent convex rib portions 31, 31 extends in the Y1 direction. On the second surface Z2 of this uneven sheet 10, multiple convex rib portions 31 and concave rib portions 36 extending in one direction (the Y1 direction) are alternately arranged to form a striped uneven surface. Each convex rib portion 31 has an internal space 32 extending in the Y1 direction. The internal space 32 of each convex rib portion 31 corresponds to the valley portion 14 of the first surface Z1. As shown in FIG. 13, the concave rib portions 36 correspond to the internal space 12 of the vertical rib portion 11 on the first surface Z1 side. In other words, the back side of the vertical ridge portion 11 is the recessed streak portion 36. In this manner, in the recessed structure, it is preferable that the first surface Z1 has a recessed shape and the second surface Z2 has a recessed shape corresponding to the first surface. With this configuration, excrement such as feces can be easily retained in the recesses of both the first surface Z1 and the second surface Z2.

[0067] 10 and 11, the convex rib portion 31 is divided into a top region 31T and a wall portion 31W in the thickness direction of the concave-convex sheet 10. The wall portion 31W is common to the wall portion 11W. In other words, in a cross-sectional view of the concave-convex sheet 10 (in the thickness direction of the concave-convex sheet 10), the convex portions (vertical rib portions 11) on the first surface Z1 and the convex portions (convex rib portions 31) on the second surface Z2 are continuous via the common wall portions 11W, 31W. The apex region 31T refers to the upper side in the thickness direction (the second surface Z2 side), i.e., the portion above the center of the thickness of the uneven sheet 10 (the second surface Z2 side). A plurality of convex portions 34 are arranged in a ridge-like manner in the apex region 31T. Specifically, the convex streak portion 31 is formed by a plurality of convex portions 34, 34 aligned along the Y1 direction, and a concave portion 35 recessed in the thickness direction from the second surface Z2 side to the first surface Z1 side is formed between adjacent convex portions 34, 34 in the Y1 direction. This gives the apex region 31T an uneven structure in which the convex portions 34 and the concave portions 35 are arranged alternately in a ridge-like manner. The convex portions 34 are hollow. Furthermore, because the plurality of convex portions 34 are arranged in a ridge-like manner, the convex streak portion 31 has narrow and wide portions that are alternately connected in the Y1 direction.

[0068] In the thickness direction of the uneven sheet 10, the height h1 of each of the convex portions 34 is the same. The height h2 of each of the concave portions 35 is also approximately the same and is lower than the height h1 of the convex portions 34. These heights h1 and h2 are measured using the surface of the apex region 11T on the first surface Z1 side as the reference plane. The height h2 of the concave portions 35 is preferably less than 0.9 times the height h1 of the convex portions 34. With regard to the height of each part that forms the uneven structure, such as the vertical rib portion 11 and the horizontal rib portion 21, "equivalent" means that when the cross section of the nonwoven fabric is observed using a digital microscope VHX-1000 manufactured by Keyence Corporation and the height of the cross section of the nonwoven fabric is measured, the height is within the range of 0.9 to 1.1 times the average measurement value.

[0069] When the uneven sheet 10 of this embodiment is used as the topsheet 2, the uneven sheet 10 may be used with the second surface Z2 side facing the skin. In this case, the convex portions 34 of the uneven structure (convex portions 34, concave portions 35) in the apex region 31T of the convex streak portion 31 are in point contact, and the concave streak portions 36 function as air passages, resulting in excellent breathability. Furthermore, the convex streak portion 31 has an undulating shape with multiple convex portions 34 connected in a ridge-like manner. This, combined with the concave-convex shape with concave portions on both sides, creates a fluffy, bulky feel and provides moderate elasticity, resulting in excellent cushioning properties. Furthermore, since the convex portions 34 are hollow as described above, the amount of compressive deformation can be increased, further improving cushioning properties.

[0070] In the present embodiment, the textured sheet 10 has a first surface Z1 in which the vertical ribs 11 and valleys 14, the horizontal ribs 21 and valleys 14, and the vertical ribs 11 and horizontal ribs 21 are seamlessly integrated with each other by at least some of the fibers fusing together. Furthermore, on the second surface Z2, the convex ribs 31 and the concave ribs 36 are seamlessly integrated with each other by at least some of the fibers fusing together. In this way, each part is continuous, and these parts are connected and supported by each other, resulting in a bulky and thick sheet. In the embossed sheet 10 of this embodiment, at least some of the fibers are fused together at intersections other than the connection portions between the respective portions. The uneven sheet 10 may have intersections where the fibers are not fused together. The uneven sheet 10 may also contain fibers other than thermoplastic fibers. That is, in the uneven sheet 10, the thermoplastic fibers may be fused together with other fibers at their intersections.

[0071] From the viewpoint of achieving excellent flexibility and cushioning properties, the thickness of the embossed sheet 10 is preferably the same as the thickness T3 of the topsheet 2 described above.

[0072] From the viewpoint of further improving the feces retention ability of the concave-convex sheet 10, it is preferable that the dimensions of the concave-convex structure are within the following ranges. The height H1 of the vertical ridge portion 11 is preferably 2.5 mm or more, more preferably 3.0 mm or more, and preferably 5.0 mm or less, more preferably 4.5 mm or less, and also preferably 2.5 mm or more and 5.0 mm or less, more preferably 3.0 mm or more and 4.5 mm or less. The height H2 of the horizontal ridge portion 21 is preferably 0.3 mm or more, more preferably 0.4 mm or more, and preferably 1.1 mm or less, more preferably 1.0 mm or less, and also preferably 0.3 mm or more and 1.1 mm or less, more preferably 0.4 mm or more and 1.0 mm or less. The height h1 of the convex portion 34 in the convex strip portion 31 is preferably 0.7 mm or more, more preferably 0.8 mm or more, and preferably 1.5 mm or less, more preferably 1.4 mm or less, and also preferably 0.7 mm or more and 1.5 mm or less, more preferably 0.8 mm or more and 1.4 mm or less. The height h2 of the recess 35 in the convex streak portion 31 is preferably 0.6 mm or more, more preferably 0.7 mm or more, and preferably 1.4 mm or less, more preferably 1.3 mm or less, and also preferably 0.6 mm or more and 1.4 mm or less, more preferably 0.7 mm or more and 1.3 mm or less.

[0073] [Method for measuring the height of the uneven structure in nonwoven fabric (uneven sheet)] The nonwoven fabric to be measured is cut into a 10 cm x 10 cm piece. If a 10 cm x 10 cm piece is not possible, cut it into as large an area as possible. Then, using a microscope (Keyence Corporation's Digital Microscope VHX-1000), the thickness (height) of each part is measured under no load. Measurements are taken at five different locations, and the average value is used as the height of each part. Note that each height is measured at a part where the convex parts in the concave-convex structure are not crushed. Through such measurements, it is possible to measure the height H1 of the vertical rib portion 11, the height H2 of the horizontal rib portion 21, and the height h1 of the convex parts 34 and the height h2 of the concave parts 35 in the convex strip portion 31 in the thickness direction of the concave-convex sheet 10.

[0074] From the viewpoint of achieving excellent flexibility and cushioning properties, the basis weight of the entire uneven sheet 10 is preferably within the following range. The basis weight of the entire embossed sheet 10 is preferably 100 g / m 2 Less than 60 g / m 2 or less, more preferably 40 g / m 2 The following is the result. The lower limit of the basis weight is not particularly limited, but from the viewpoint of further improving the texture of the nonwoven fabric, it is preferably 8 g / m 2 More preferably, 10 g / m 2 More preferably, 15 g / m 2 That's all.

[0075] [Method for measuring basis weight of nonwoven fabric] Cut the nonwoven fabric to be measured into a 10cm x 10cm piece. If a 10cm x 10cm piece is not possible, cut it into as large an area as possible. Measure the weight using a balance and divide it by the area of ​​the nonwoven fabric to obtain the basis weight. When removing the nonwoven fabric to be measured from a commercially available absorbent article, the adhesive used in the absorbent article is solidified using a cooling method such as a cold spray, and the nonwoven fabric to be measured is carefully peeled off and measured. At this time, the adhesive is removed using an organic solvent. This method is the same for all measurements of other nonwoven fabrics in this specification.

[0076] The uneven sheet 10 of this embodiment has a two-layer structure consisting of a first fiber layer forming the first surface Z1 and a second fiber layer forming the second surface Z2. In this case, the first fiber layer and the second fiber layer may be composed of the same type of constituent fiber, or may be composed of different types of constituent fiber. The first and second fiber layers may have the same basis weight of constituent fibers, or may have different basis weights.

[0077] A manufacturing method for the uneven sheet 10 of this embodiment will be described. In the manufacturing method of this embodiment, a support male member 120 shown in FIG. 14(A) and a support female member 130 shown in FIG. 14(B) are used to shape a fiber web 110 before it is made into a nonwoven fabric. The support male member 120 has protrusions 121 spaced apart in one direction and in a direction perpendicular to that. On the other hand, the support female member 130 has protrusions 131 that are continuous in one direction. The protrusions 121 of the support male member 120 and the protrusions 131 of the support female member 130 are shaped so that they can be inserted loosely without interfering with each other. Then, as shown in FIG. 14(C), the fiber web 110 is placed on the support male member 120, and the support female member 130 presses down on the fiber web 110 to sandwich it and shape it.

[0078] The support male member 120 has a plurality of protrusions 121 corresponding to the positions where the valleys 14 surrounded by the vertical ribs 11, 11 and the horizontal ribs 21, 21 of the uneven sheet 10 are formed. Between the protrusions 121, 121, there are support recesses 122 corresponding to the positions where the top regions 11T of the vertical ribs 11 on the first surface Z1 side are formed. As a result, the support male member 120 has an uneven shape, and the protrusions 121 and the support recesses 122 are arranged alternately in different directions in a plan view. The support bottoms 123 of the support recesses 122 have a structure that allows hot air to pass through, and for example, multiple holes are arranged (not shown). When the uneven sheet 10 is manufactured by continuously or sequentially shaping the transported fiber web 110, the support (support male member, support In the female material, the Y1 direction and X1 direction of the embossed sheet 10 correspond to, for example, the machine direction (MD direction) and the CD direction perpendicular to the MD direction.

[0079] From the viewpoint of more effectively applying hot air to the fiber web 110, holes may be drilled in the support male element 120 corresponding to the support recesses 122. The protrusions 121 may be rectangular or cylindrical. When viewed from above, the protrusions 121 are depicted as having a rectangular shape relative to the machine direction (MD) of the uneven sheet 10 in the figure, but the shape in plan view is not particularly limited and may be, for example, a diamond shape. From the viewpoint of making it easier for the fibers to penetrate into the support male element 120 and further maintaining the formability and thickness of the uneven sheet 10, it is preferable that the shape of the protrusions 121 is a rectangular column and has a square shape when viewed from above.

[0080] The support female member 130 has protrusions 131 that correspond to the support recesses 122 of the support male member 120 and are continuous in one direction in plan view. The spaces between the protrusions 131 correspond to the protrusions 121 of the support male member 120 and are support recesses 132 that are continuous in the one direction. This gives the support female member 130 an uneven shape, with the protrusions 131 and the support recesses 132 arranged alternately. The support bottoms 133 of the support recesses 132 have a structure that allows hot air to pass through, and are provided with, for example, multiple holes. The distance between the protrusions 131 is wider than the width of the protrusions 121 of the support male member 120. This distance is appropriately set so that the fiber web 110 can be sandwiched between the protrusions 121 of the support male member 120 and the protrusions 131 of the support female member 130, thereby favorably forming a wall portion in which the fibers are oriented in the thickness direction.

[0081] In the manufacturing method of this embodiment, first, a fibrous web 110 is fed from a carding machine (not shown) to a web shaping device so that the fibrous web 110 has a predetermined thickness. The fibrous web 110 may have a multi-layer structure. For example, the fibrous web 110 may be a laminated web in which a first fibrous web and a second fibrous web are laminated.

[0082] Next, as shown in Figure 14(C), a fibrous web 110 containing thermoplastic fibers is placed on the support male member 120, and the support female member 130 is pressed into the support male member 120 from above the fibrous web 110. At this time, the protrusions 121 of the support male member 120 are inserted into the support recesses 132 of the support female member 130. Also, the protrusions 131 of the support female member 130 are inserted into the support recesses 122 of the support male member 120 (see Figure 15). This causes the fibers to be oriented in the thickness direction and the planar direction. Furthermore, the support female member 130 does not enter the portion of the support recesses 122 between the protrusions 121, 121 of the support male member 120 that corresponds to the support recesses 132 of the support female member 130. However, because the fibrous web 110 is sandwiched between the protrusions 131 at both ends of the support female member 130, the fibers that were in the support recesses 122 are stretched, changing the fiber orientation. The fibers that are normally oriented in one direction along the extending protrusions 131 change orientation as the fibers in the support recesses 122 are pulled. In this way, a nonwoven fiber web 110 can be produced in which the orientation changes when viewed from above.

[0083] 15(A) and (B) show the state in which the protrusions 121 of the support male member 120 are inserted into the support recesses 132 of the support female member 130. By achieving this state, a fiber layer corresponding to the bottom of the valley portion 14 is formed. Furthermore, between the bottom of the support recess 122 and the top of the protrusion 131, the fibers are oriented in the planar direction. Because the protrusions 131 obstruct the hot air, the formed fiber layer is less fused and a smooth fiber layer is achieved. As a result, a fiber layer corresponding to the top region 11T of the vertical ridge portion 11 on the first surface Z1 side is formed.

[0084] Next, the support female element 130 inserted into the support male element 120 is removed, and as shown in Figure 16, hot air W at a temperature that allows each fiber of the fiber web 110 to be suitably fused is blown onto the fiber web 110 to further fuse the fibers together. In this case, hot air W is blown onto the fiber web 110 from the side opposite the concave-convex sheet 10. Considering the typical fiber materials used in this type of product, the temperature of the hot air W is preferably 0°C to 70°C higher than the melting point of the thermoplastic fiber that makes up the fiber web 110, and more preferably 5°C to 50°C higher. The speed of the hot air W depends on the height of the protrusions 121 of the support male element 120, but is preferably 2 m / s or more, more preferably 3 m / s or more. This allows for sufficient heat transfer to the fibers, fusing the fibers together and ensuring sufficient fixation of the uneven shape. Furthermore, the speed of the hot air W is preferably 100 m / s or less, more preferably 80 m / s or less. This prevents excessive heat transfer to the fibers and improves the texture of the uneven sheet 10.

[0085] By reducing the surface roughness of the support female material, it is possible to prevent unfused fibers from clinging to the support female material 130 and to remove the support female material 130 during the hot air W blowing process. In other words, after producing the web, the support male material 120 can be inserted into the support female material 130, and the support female material 130 can be removed as is, and then the web can be treated with the above-mentioned hot air W. This makes processing easier. Furthermore, in this embodiment, the surface to which the hot air is applied during production is the second surface Z2 side, but the hot air may be applied from the surface that will become the first surface Z1, so that there are more fusion points between the fibers on the first surface Z1 side.

[0086] The lower surface of the obtained uneven sheet 10 in FIG. 16 is the first surface Z1 side, and the opposite surface is the second surface Z2 side. In other words, the first surface Z1 side of the uneven sheet 10 is the side where the support male material 120 is arranged, and the second surface Z2 side is the side where the hot air W is blown. Therefore, due to the difference in the amount of hot air W blown, there are more fusion points between fibers in the apex region 31T on the second surface Z2 side than in the apex region 11T on the first surface Z1 side. Furthermore, due to the difference in the amount of heat, the surface of the apex region 11T on the first surface Z1 side feels less rough and is more pleasant to the touch than the surface of the apex region 31T on the second surface Z2 side. Similar effects can also be obtained depending on the distance from the hot air W. Furthermore, by inserting the support male element 120 into the support female element 130 with the fiber web 110 sandwiched between them, the fibers in the apex region 31T on the second surface Z2 side are pulled and move further toward the support male element 120. Therefore, the amount of fiber in the apex region 31T on the second surface Z2 side formed on the apex of the protrusion 121 of the support male element 120 becomes smaller than the apex region 11T on the first surface Z1 side formed on the bottom of the support recess 122 of the support male element 120.

[0087] Although the present invention has been described above based on its preferred embodiments, the present invention is not limited to the above-described embodiments and may be combined with other embodiments. For example, the absorbent body 4 provided in the above-described diaper 1 has a two-layer structure consisting of an upper absorbent body 41 and a lower absorbent body 43, but the absorbent body 4 may have a single-layer structure. Furthermore, the topsheet is not limited to the configurations shown in Figures 4 to 16. For example, the topsheet may be a composite sheet 70 in which a first sheet 71 and a second sheet 72 are laminated and joined to each other at a plurality of joining portions 73, and the first sheet 71 may have convex portions that protrude in a direction away from the second sheet 72 at locations other than the joining portions 73, and the joining portions 73 may be concave portions (see Figure 17). Examples of sheets of this configuration include those described in JP 2015-112343 A and JP 2019-205685 A. [Example]

[0088] The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[0089] Example 1 In Example 1, a topsheet having a concave-convex structure was produced by the following method. The first fiber web (basis weight 10 g / m) was made of thermoplastic fibers of a core-sheath type (polyethylene terephthalate (PET) (core): polyethylene (PE) (sheath) = 6:4 (mass ratio)) with a fineness of 1.3 dtex. 2 ) was prepared, and a second fiber web (basis weight 25 g / m) was prepared using thermoplastic fibers of a core-sheath type (polyethylene terephthalate (PET) (core): polyethylene (PE) (sheath) = 6:4 (mass ratio)) with a fineness of 4.4 dtex. 2 ) was produced. These first and second fiber webs were laminated to produce a laminated web. Next, the laminated web was placed between the support male member 120 and the support female member 130 shown in Figures 14 and 15 and subjected to a shaping treatment. Next, the support female member 130 was removed and a fusion treatment was performed by blowing hot air W, producing a nonwoven fabric having a first surface and a second surface as shown in Figures 4 and 9. In this case, the support male member 120 used had cylindrical protrusions 121 with a height of 10 mm and a diameter of 2 mm when viewed from above. The pitch of the protrusions 121 was 5 mm in both the MD and CD directions. The support female member 130 used was made of metal and had linear protrusions 131 with a width of 2 mm, and was pressed between the protrusions 121 of the support male member 120. Adjacent protrusions 121, 121 of the support female member 130 were arranged at a pitch of 5 mm, and the space into which the fibers entered when the support male member 120 and the support female member 130 were pressed together was 0.5 mm on one side, for a total of 1 mm on both sides of the protrusions 121 of the support male member 120. This was used as the nonwoven fabric sample of Example 1. The hot air blowing treatment was carried out under conditions of a temperature of 160°C, an air speed of 6 m / sec, and a blowing time of 6 seconds. A topsheet having a concave-convex structure was obtained by the above method.

[0090] In Example 1, the upper absorbent body was produced by the following method. Fluff pulp and a water-absorbent polymer were uniformly mixed to produce a mixed stack. This mixed stack was then wrapped around a core wrap sheet (basis weight 10 g / m) made of nonwoven fabric. 2 The pulp basis weight of the absorbent core of the upper absorbent layer was 100 g / m 2 It was.

[0091] In Example 1, the lower absorbent body was prepared by the following method. Mounting paper (basis weight 14g / m 2 ) and SMS nonwoven fabric (basis weight 10g / m 2 The water-absorbent polymer was a hot melt adhesive (basis weight 10 g / m) that was applied to the backing paper and the SMS nonwoven fabric. 2 The pulp basis weight of the absorbent core of the lower absorbent body was 0 g / m 2 It was.

[0092] An absorbent body 4 was produced using the obtained upper and lower absorbent bodies. A topsheet 2 was then placed on the skin-facing surface of the absorbent body 4 to form a composite. The composite was formed with the first surface of the topsheet (see Figure 4) facing the skin. Apart from this composite, the components of a commercially available diaper "Merry's Tape Type S Size" were used to produce the diaper shown in Figure 1 equipped with this composite.

[0093] Example 2 A single-layer web (basis weight 40 g / m) was fabricated using thermoplastic fibers of a core-sheath type (polyethylene terephthalate (PET) (core): polyethylene (PE) (sheath) = 6:4 (mass ratio)) with a fineness of 1.8 dtex. 2 ) was prepared, and a topsheet having a concave-convex structure was prepared in the same manner as in Example 1, except that the single-layer web was subjected to a shaping treatment. Furthermore, a diaper was produced using an absorbent core 4 having the specifications shown in Table 1 below. The absorbent core 4 and the diaper were produced in the same manner as in Example 1.

[0094] Example 3 The basis weight of the first fibrous web is 20 g / m 2The basis weight of the second fibrous web is 50 g / m 2 A topsheet having a concave-convex structure was produced in the same manner as in Example 1, except for the above. Furthermore, a diaper was produced using an absorbent core 4 having the specifications shown in Table 1 below. The absorbent core 4 and the diaper were produced in the same manner as in Example 1.

[0095] Example 4 In Example 4, a topsheet having a concave-convex structure was produced by the following method. Similar to the method described in JP 2015-112343 A, a strip-shaped first sheet was fed between a first roll and a second roll whose peripheral surfaces interlocked with each other, deforming the first sheet into a concave-convex shape. Next, the first sheet was moved along the peripheral surface of the first roll from the interlocking portion, and then the second sheet was fed so as to overlap the first sheet. Both sheets were partially bonded by being pressed between the convex portion of the first roll and the heat roll under heat. The concave-convex shapes of the first roll and the second roll, and the pattern of the bond formed by the first roll and the heat roll, were made different between the center and side portions of the first sheet.

[0096] In this method, the depth of engagement between the first roll and the second roll was adjusted. Specifically, when the outer periphery length of the convex portion in the thickness direction cross section along the longitudinal direction of the concave-convex sheet is L7 and the length of the bottom of the convex portion in the same direction is L2, the ratio L7 / L2 was adjusted to 1.5 (see Figure 17). The concave portions in this concave-convex sheet were formed in areas other than the convex portions. A sheet having a first layer and a second layer was used as the first sheet. The sheets constituting the first and second layers were made by the air-through method and had a basis weight of 18 g / m. 2The nonwoven fabric used was the following. The nonwoven fabric constituting the first layer was made of first fibers. The nonwoven fabric constituting the second layer was made of first fibers (fineness 2.3 dtex) and second fibers (fineness 2.3 dtex), and the mass ratio of the first fibers to the second fibers in the second layer was first fibers / second fibers = 70 / 30. The first fibers and second fibers used were fibers with a core-sheath structure in which the core component was polyethylene terephthalate (PET) and the sheath component was polyethylene (PE). The diameter ratio of the first fibers to the sheath component, i.e., core / sheath, was 1.57, and the diameter ratio of the second fibers to the core component, i.e., core / sheath, was 1.17. The second sheet was made of the same nonwoven fabric as the one constituting the first layer.

[0097] In Example 4, a diaper was produced using the topsheet obtained by the above-mentioned method and an absorbent core 4 having the specifications shown in Table 1 below. The absorbent core 4 and the diaper were produced by the same method as in Example 1.

[0098] Comparative Examples 1 to 3 In Comparative Example 1, a topsheet was produced in the same manner as in Example 1, except that no shaping treatment was performed. Such a topsheet did not have a concave-convex structure. In Comparative Example 1, the upper absorbent body and the lower absorbent body had the same configuration as in Example 1. In Comparative Example 2, the topsheet had the same configuration as in Comparative Example 1, the lower absorbent body of Example 1 was used as the upper absorbent body, and the lower absorbent body had the specifications shown in Table 1 below. Such a lower absorbent body was produced in the same manner as in Example 1. In Comparative Example 3, the topsheet and lower absorbent body had the same configuration as in Example 1, and the lower absorbent body of Example 2 was used as the upper absorbent body. Furthermore, in Comparative Examples 1 to 3, the diapers were produced in the same manner as in Example 1.

[0099] For the diapers of each Example and Comparative Example, the thicknesses and compression ratios of the absorbent core 4, topsheet 2, upper absorbent core 41, lower absorbent core 43, and absorbent core 4 before and after pressure application were measured using the methods described above. The measurement results are shown in Table 1 below.

[0100] [Performance evaluation] For each of the diapers of the Examples and Comparative Examples, the amount of wetback was measured by the following method. First, three 2 kg weights were placed on the skin-facing side of the diaper in an unfolded state, and 30 g of artificial urine was poured into the excretory-facing part of the diaper four times at 5-minute intervals. After each pour, the diaper was left to stand for 5 minutes. After that, the weights were removed, and a filter paper (70 mm × 70 mm, basis weight 120 g / m) was placed on the topsheet of the excretory-facing part. 2 ) was placed on the filter paper, and a weight (with an equal contact area with the filter paper) was placed on top of the filter paper, and the diaper was pressurized at 3 kPa for 2 minutes. The weight of the filter paper before absorption was then subtracted from the weight of the filter paper that had absorbed the artificial urine to measure the amount of artificial urine absorbed by the filter paper. The above procedure was performed three times for each evaluation subject, and the average value was taken as the amount of liquid return.

[0101] The composition of the artificial urine was 1.94% by mass of urea, 0.7954% by mass of sodium chloride, 0.1106% by mass of magnesium sulfate (heptahydrate), 0.0621% by mass of calcium chloride (dihydrate), 0.1979% by mass of potassium sulfate, 0.0035% by mass of polyoxyethylene lauryl ether, and ion-exchanged water (balance).

[0102] [Table 1]

[0103] As is clear from Table 1, the diapers of Examples 1 to 4, which have topsheets with a lower compression rate than the absorbent body, had less liquid return than the diapers of Comparative Examples 1 to 3, which have topsheets with a higher compression rate than the absorbent body. The above results demonstrate that the absorbent article of the present invention can prevent body fluids (urine) from returning to the topsheet. [Explanation of symbols]

[0104] 1. Absorbent articles 2 Surface sheet 3 Back sheet 3a Exterior non-woven fabric 4. Absorbent 5. Absorbent body 6 Leak proof cuff 7 Side Panel 8 Fastening Tape 10 Textured sheet 41 Upper absorber 43 Lower absorber 60 Cuff forming sheet 61 Cuff forming elastic member 63 Leg elastic member A. Ventral part B Dorsal part C Inseam X vertical direction Y horizontal direction

Claims

1. An absorbent article comprising a topsheet and an absorbent body, having a longitudinal direction corresponding to the front-to-back direction of a wearer and a lateral direction perpendicular to the longitudinal direction, and having a ventral side portion, a crotch portion and a back side portion along the longitudinal direction, The top sheet has an uneven structure, The topsheet has a lower compressibility than the absorbent core, as calculated by the following formula: Compression ratio (%) = (Tb / Ta) x 100 Ta: The thickness of the absorbent article in a compressed state when the absorbent article is unfolded and a load of 3 kPa is applied Tb: thickness of the absorbent article before pressure application when the absorbent article is unfolded and placed under no pressure

2. The absorbent body has an upper absorbent body and a lower absorbent body, The absorbent article according to claim 1 , wherein the compressibility of the topsheet is lower than that of the upper absorbent body.

3. The absorbent body has an upper absorbent body and a lower absorbent body, The absorbent article according to claim 1 or 2, wherein the compressibility satisfies the following magnitude relationship (1): The upper absorbent body > the topsheet > the lower absorbent body... (1)

4. the topsheet has a first surface and a second surface, and in the uneven structure, the first surface has an uneven shape, and the second surface has an uneven shape corresponding to the first surface, 3. The absorbent article of claim 1, wherein, in a cross-sectional view of the top sheet, when the convex portions in the uneven shape of the first surface and the convex portions in the uneven shape of the second surface are each divided into a top region and a wall portion, the convex portions on the first surface and the convex portions on the second surface are continuous via a common wall portion.

Images