Absorbent article

Abstract

To provide an absorbent article which has an increased drying property on a surface sheet.SOLUTION: In an absorbent article, a surface sheet (20) includes a skin side part (21) and a non-skin side part (22). Average fineness of fibers constituting the non-skin side part (22) is smaller than average fineness of fibers constituting the skin side part (21). An absorbent core (121) has a compression part (123) compressed from a skin side in a thickness direction. When a liquid drainage test for obtaining a liquid drainage index related to an absorption rate and an absorption amount of artificial urine is performed based on a measurement result at a prescribed position by a moisture meter after dripping the artificial urine of 40 ml four times to the prescribed position on the surface sheet (20), the liquid drainage index is 50% or less.SELECTED DRAWING: Figure 10

Description

[Technical field]

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

[0002] The absorbent body of the disposable diaper of Patent Document 1 has non-stacking parts extending in the vertical direction. Therefore, the non-stacking parts become deformation starting points, and the absorbent body fits the wearer's body. Furthermore, by having a top sheet present in the non-stacking parts, the formation of a space between the top sheet and the absorbent body is restricted, and liquid excreted in the non-stacking parts is smoothly transferred downward in the thickness direction. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-30109 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in Patent Document 1, in order to make the topsheet exist (push) in the non-stacking portion, the fineness of the fibers in the lower layer of the topsheet is made higher than that of the upper layer, and the bonding points between the fibers are sparse, making it easier to stretch the lower layer. In this case, the gaps between the fibers in the lower layer of the topsheet are larger than those in the upper layer. Therefore, the capillary phenomenon from the upper layer to the lower layer of the topsheet does not work, and the excreted liquid is not drawn into the inside of the topsheet well. Therefore, liquid is likely to remain on the topsheet, and the dryness of the topsheet is not sufficiently obtained.

[0005] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide an absorbent article with improved dryness on the topsheet (skin side). [Means for solving the problem]

[0006] The main invention to achieve the above object is: In a deployed state, the device has a longitudinal direction, a width direction, and a thickness direction which are perpendicular to each other, An absorbent article having an absorbent core and a top sheet, the topsheet has a skin side portion located on the skin side in the thickness direction, and a non-skin side portion located on the non-skin side in the thickness direction relative to the skin side portion, the average fineness of the fibers constituting the non-skin side portion is smaller than the average fineness of the fibers constituting the skin side portion; The absorbent core has a compressed portion compressed from the skin side in the thickness direction, This absorbent article is characterized in that when 40 ml of artificial urine is dropped four times onto a specified position on the top sheet, a drainage test is performed to determine a drainage index related to the absorption rate and absorption amount of the artificial urine based on the measurement results of the specified position using a moisture meter, and the drainage index is 50% or less. Other features of the present invention will become apparent from the following detailed description of the present invention and the accompanying drawings. Effect of the Invention

[0007] According to the present invention, it is possible to provide an absorbent article having improved dryness on the topsheet (skin side). [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view of a diaper 1. [Diagram 2] FIG. 1 is a schematic plan view of a diaper 1 in an open and stretched state, as viewed from the skin side. [Diagram 3] FIG. 3 is a schematic cross-sectional view taken along line AA in FIG. 2. [Figure 4] 3 is a schematic cross-sectional view taken along the center line CL in FIG. 2. [Diagram 5] FIG. 5A is a schematic cross-sectional view of the topsheet 20, and FIG. 5B is a plan view of the topsheet 20 as viewed from the skin side. [Figure 6]FIG. 6A is an explanatory diagram of the fibers that make up the topsheet 20, and FIG. 6B is an explanatory diagram of the topsheet 20 when worn. [Figure 7] 7A and 7B are plan views of the absorbent body 12 as viewed from the skin side. [Figure 8] 8A and 8B are explanatory views of the compression unit 123. [Figure 9] FIG. 13 shows the results of a drainage test. [Figure 10] 10A and 10B show the results of the drainage test. [Figure 11] FIG. 2 is an explanatory diagram of a jig 50 for installing the diaper 1. [Figure 12] 12A and 12B are explanatory diagrams showing modified examples of the top sheet 20. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] At least the following points will become apparent from the description of this specification and the accompanying drawings. (Aspect 1) The absorbent article has, in an unfolded state, a longitudinal direction, a width direction, and a thickness direction which are perpendicular to each other, and comprises an absorbent core and a top sheet, wherein the top sheet has a skin side portion located on the skin side in the thickness direction and a non-skin side portion located on the non-skin side in the thickness direction of the skin side portion, the average fineness of the fibers constituting the non-skin side portion is smaller than the average fineness of the fibers constituting the skin side portion, the absorbent core has a compressed portion compressed from the skin side in the thickness direction, and when 40 ml of artificial urine is dropped four times at a predetermined position on the top sheet, and a drainage test is performed to determine a drainage index related to the absorption speed and absorption amount of the artificial urine based on the measurement results of the predetermined position with a moisture meter, the drainage index is 50% or less.

[0010] According to the first aspect, the gaps between the fibers are smaller in the non-skin side portion than in the skin side portion, and excreted liquid can easily migrate from the skin side portion to the non-skin side portion. Furthermore, excreted liquid that has migrated to the skin side of the absorbent core is easily drawn into the absorbent core by the compressed portion with high fiber density. Therefore, excreted liquid is less likely to remain on the topsheet, and the dryness of the topsheet is improved. Furthermore, compared to when the drainage index is higher than 50%, the absorption speed and amount of excreted liquid on the topsheet is increased, and the dryness of the topsheet is improved.

[0011] (Aspect 2) The absorbent article according to aspect 1, The skin side portion of the topsheet has a higher breaking strength in the longitudinal direction than the non-skin side portion.

[0012] According to the second aspect, the non-skin side portion is easily crushed when the wearer's body pressure is applied, and the gaps between the fibers of the non-skin side portion become smaller. Therefore, the excreted liquid is easily transferred from the skin side portion to the non-skin side portion. On the other hand, the skin side portion is not easily crushed and has a sufficient thickness (bulk), so that the excreted liquid absorbed by the absorbent core is not easily transferred back onto the topsheet, and the dryness of the topsheet is improved and easily maintained.

[0013] (Aspect 3) An absorbent article according to aspect 1 or aspect 2, The total length of the fibers constituting the non-skin side portion of the topsheet is longer than the total length of the fibers constituting the skin side portion of the topsheet.

[0014] According to the third aspect, when the wearer's body pressure is applied, the gaps between more fibers narrow, making it easier for excreted fluid to migrate from the skin side to the non-skin side, thereby improving the dryness of the topsheet.

[0015] (Aspect 4) An absorbent article according to any one of Aspects 1 to 3, The present invention is characterized in that it has a sheet adjacent to the non-skin side of the top sheet in the thickness direction, and the hydrophilicity of the skin side of the sheet is higher than the hydrophilicity of the skin side of the top sheet.

[0016] According to the fourth aspect, excreted liquid that has migrated from the skin side portion of the topsheet to the non-skin side portion is more likely to migrate to the highly hydrophilic sheet, and as a result, the excreted liquid gradually migrates into the absorbent article, making it difficult for the excreted liquid to remain on the topsheet, improving the dryness of the topsheet.

[0017] (Aspect 5) An absorbent article according to any one of Aspects 1 to 4, The compressing section is characterized in that it does not compress the top sheet.

[0018] According to the fifth aspect, a gap is easily formed between the topsheet and the absorbent core. The excreted liquid absorbed by the absorbent core is easily stored temporarily in the gap and is less likely to flow back onto the topsheet. This makes it easier to maintain the dryness of the topsheet.

[0019] (Aspect 6) The absorbent article according to aspect 5, The surface side of the topsheet is characterized in that a plurality of protrusions extending in the longitudinal direction are arranged at intervals in the width direction.

[0020] According to the sixth aspect, the contact area between the topsheet and the wearer can be reduced, making the wearer less likely to feel the dampness of the absorbent article, improving comfort. In addition, when the user touches the topsheet to check the dryness of the topsheet, the user's fingertips can easily move smoothly in the longitudinal direction, making it easier for the user to recognize that the product has a high level of dryness on the topsheet.

[0021] (Aspect 7) An absorbent article according to any one of Aspects 1 to 4, The compressing section is characterized by compressing the top sheet together with the absorbent core.

[0022] According to the seventh aspect, excreted liquid that flows into the densified compressed parts is more likely to be drawn from the topsheet to the absorbent core by capillary action. In addition, the visibility of the compressed parts is improved, so that the user can easily recognize that the product is one that easily absorbs excreted liquid.

[0023] (Aspect 8) An absorbent article according to any one of aspects 1 to 7, The top sheet is characterized by having a through hole penetrating the top sheet in the thickness direction.

[0024] According to aspect 8, the excreted liquid falls into the inside of the absorbent article through the through-holes of the topsheet, so that the absorption rate of the excreted liquid on the topsheet is increased, and the dryness of the topsheet can be improved.

[0025] (Aspect 9) An absorbent article according to any one of aspects 1 to 8, The skin side portion of the topsheet is characterized by having a high basis weight region in which the basis weight of the fibers is high, and a low basis weight region in which the basis weight of the fibers is lower than that of the high basis weight region.

[0026] According to the ninth aspect, the high basis weight region can increase the thickness or density of a portion of the skin side portion. By increasing the thickness (bulk) of the high basis weight region, it is possible to suppress the backflow of excreted liquid. Also, by increasing the density of the high basis weight region, it becomes easier for excreted liquid on the top sheet to be drawn in by capillary action.

[0027] (Aspect 10) The absorbent article according to aspect 9, The high basis weight region is characterized in that it protrudes toward the skin side more than the low basis weight region.

[0028] According to the tenth aspect, it is possible to form an uneven surface on the skin side of the topsheet, thereby reducing the contact area between the topsheet and the wearer. This makes it difficult for the wearer to feel the dampness of the absorbent article, improving comfort.

[0029] (Aspect 11) An absorbent article according to any one of Aspects 1 to 10, The present invention is characterized in that when 40 ml of artificial urine is dropped onto the top sheet four times, a test is conducted to measure the amount of rewet of the artificial urine returning to the top sheet, and the rewet amount is 1.0 g or less.

[0030] According to the eleventh aspect, compared to a case where the rewet amount is more than 1.0 g, the excreted liquid absorbed by the absorbent core can be prevented from returning to the topsheet, and the dryness of the topsheet can be maintained.

[0031] === Implementation form === The absorbent article according to the present invention will be described taking as an example a pants-type disposable diaper 1 for infants (hereinafter also referred to as "diaper 1"). However, the absorbent article according to the present invention also includes tape-type disposable diapers, shorts-type napkins, absorbent pads, sanitary napkins and other absorbent articles. Furthermore, the wearer of the absorbent article is not limited to infants, but may be an adult or a living organism such as an animal.

[0032] <Diaper 1 composition> Fig. 1 is a schematic perspective view of a diaper 1. Fig. 2 is a schematic plan view of the diaper 1 in an unfolded and stretched state, as viewed from the skin side. Fig. 3 is a schematic cross-sectional view taken along line AA in Fig. 2. Fig. 4 is a schematic cross-sectional view taken along center line CL in Fig. 2.

[0033] The "stretched state" of the diaper 1 refers to the state in which the diaper 1 as a whole is stretched without wrinkles, specifically, the state in which each component constituting the diaper 1 (e.g., the absorbent body 10 and waist circumference portions 30, 40 described below) is stretched until the dimensions of the component alone match or are close to those of the component. The "unfolded state" of the diaper 1 refers to the state in which the diaper 1 is opened and unfolded in a plane after a pair of side joint portions 2 provided on both sides of the diaper 1 are separated.

[0034] The diaper 1 has a vertical direction, a width direction, and a front-rear direction that are perpendicular to one another, and has a waist opening BH and a pair of leg openings LH. The upper side in the vertical direction corresponds to the waist opening BH side, and the lower side corresponds to the crotch side. The front side in the front-rear direction corresponds to the wearer's abdomen side, and the rear side corresponds to the wearer's back side. The width direction is a direction along the stretch direction of the elastic threads 33, 43 of the front waist portion 30 and the rear waist portion 40. The vertical direction is a direction along the orthogonal direction that is perpendicular to the stretch direction.

[0035] The diaper 1 is a so-called three-piece pants-type diaper having a liquid-absorbent main body 10 and a pair of waist-circulating portions 30, 40. Of the pair of waist-circulating portions, the one covering the wearer's abdominal side is also referred to as the front waist-circulating portion 30, and the one covering the wearer's dorsal side is also referred to as the rear waist-circulating portion 40.

[0036] In the developed state of FIG. 2, the diaper 1 has a longitudinal direction, a width direction, and a thickness direction that are perpendicular to each other. The longitudinal direction is along the longitudinal direction of the absorbent body 10 and along the vertical direction of the pants-type diaper 1. The thickness direction is the direction in which the materials constituting the diaper 1 are layered, as shown in FIG. 3. In the thickness direction, the side that contacts the wearer's skin is the skin side, and the opposite side is the non-skin side. In the developed state, the front waistline portion 30 and the rear waistline portion 40 are aligned parallel to each other with a gap in the longitudinal direction, the absorbent body 10 is stretched between them, and each end of the absorbent body 10 in the longitudinal direction is joined and fixed to the skin side of the nearest waistline portion 30, 40, so that the external shape is approximately H-shaped in plan view. From this state, the diaper 1 is folded in half at the longitudinal center line CL. In this folded state, the mutually opposing front waistline portion 30 and rear waistline portion 40 are joined and connected at both widthwise sides to form a pair of side joint portions 2. The side joint portions 2 are formed by known joining means such as welding or adhesion.

[0037] The absorbent body 10 has an absorbent body 12, a liquid-permeable top sheet 20 arranged on the skin side of the absorbent body 12, and a back sheet 13 arranged on the non-skin side of the absorbent body 12. The back sheet 13 has a two-layer structure of a liquid-impermeable sheet 13a and a hydrophobic exterior sheet 13b arranged on the non-skin side. However, the absorbent body 10 may also include other sheet members. For example, a second sheet (not shown) may be provided between the top sheet 20 and the absorbent body 12 in the thickness direction.

[0038] The absorbent body 12 has an absorbent core 121 and a core wrap sheet 122 that covers the outer peripheral surface of the absorbent core 121. The absorbent core 121 is a member that absorbs and retains excreted liquids such as urine, and is formed of liquid-absorbent fibers such as pulp fibers mixed with superabsorbent polymer (SAP). Examples of the core wrap sheet 122 include liquid-permeable sheet members such as tissue paper and nonwoven fabric.

[0039] A pair of leakage prevention walls 15 are provided along the longitudinal direction of the absorbent main body 10 on both sides in the width direction of the absorbent main body 10. In Fig. 4, a part of the exterior sheet 13b extends outward beyond both ends of the absorber 20 in the width direction and is folded toward the skin at multiple points to form the pair of leakage prevention walls 15. A leakage prevention wall elastic member 16 such as rubber thread is attached to the tip of the leakage prevention wall 15 in a stretched state along the longitudinal direction of the absorbent main body 10, and the leakage prevention wall 15 is configured to be able to stand up toward the skin side. Further, leg elastic members 17 such as rubber threads are attached to both widthwise sides of the absorbent body 10 in a stretched state along the longitudinal direction of the absorbent body 10.

[0040] The front waist portion 30 and the rear waist portion 40 each have a skin side sheet 31, 41, a non-skin side sheet 32, 42, and a plurality of waist elastic members 33, 43 such as rubber threads. The plurality of waist elastic members 33, 43 are arranged side by side in the vertical direction between the skin side sheet 31, 41 and the non-skin side sheet 32, 42, and are attached in a stretched state in the width direction. The elasticity of the waist elastic members 33, 43 allows the front waist portion 30 and the rear waist portion 40 to fit the waist of the wearer.

[0041] Also, cover sheets 34, 44 may be provided so as to cover the upper end of the absorbent main body 10 from the skin side. The cover sheets 34, 44 can prevent the absorbent main body 10 from opening. Also, print sheets 35, 45 on which a pattern or the like is printed may be provided between the skin side sheets 31, 41 and the non-skin side sheets 32, 32.

[0042] As shown in Fig. 3, the planar shapes of the front waistline portion 30 and the rear waistline portion 40 in the unfolded and stretched state are different. The front waistline portion 30 has a vertical length that is roughly the same as the side joint portion 2, and is rectangular in shape that is long in the width direction. The rear waistline portion 40 has a rectangular portion that overlaps with the front waistline portion 30, and a roughly trapezoidal portion 40E that extends downward from the rectangular portion 30. The extending portion 40E can cover the buttocks of the wearer.

[0043] The basic configuration of the diaper 1 has been described above, but the above configuration is merely an example and is not intended to be limiting. For example, the front waistline portion 30 and the rear waistline portion 40 may be formed from a single continuous member, or an exterior member may be provided for the crotch portion connecting the front waistline portion 30 and the rear waistline portion 40. Furthermore, the elastic members such as the waistline elastic members 33, 43 may be sheet-like elastic members instead of rubber threads.

[0044] ===Dryness of the top sheet 20=== Fig. 5A is a schematic cross-sectional view of the topsheet 20, and Fig. 5B is a plan view of the topsheet 20 (part) as viewed from the skin side. Fig. 6A is an explanatory diagram of the fibers constituting the topsheet 20, and Fig. 6B is an explanatory diagram of the topsheet 20 when worn. Figs. 7A and 7B are plan views of the absorbent body 12 as viewed from the skin side. Figs. 8A and 8B are explanatory diagrams of the compressed portions 123. Figs. 9, 10A, and 10B show the results of a drainage test.

[0045] As shown in Fig. 6A, the topsheet 20 has a skin side portion 21 located on the skin side in the thickness direction, and a non-skin side portion 22 located on the non-skin side in the thickness direction of the skin side portion 21. Note that, as shown in Fig. 5A, the topsheet 20 of this embodiment is a sheet having projections and recesses, but for ease of understanding of the drawings, the topsheet 20 is illustrated flat in Figs. 6A and 6B.

[0046] As shown in FIG. 6A, the average fineness of the fibers f2 constituting the non-skin side portion 22 of the topsheet 20 is smaller than the average fineness of the fibers f1 constituting the skin side portion 21. In other words, the fibers f2 constituting the non-skin side portion 22 are thinner than the fibers f1 constituting the skin side portion 21. Therefore, in the skin side portion 21, it is difficult for additional fibers f1 to penetrate between the fibers f1, and the fibers f1 are sparsely present. In contrast, in the non-skin side portion 22, additional fibers f2 are likely to penetrate between the fibers f2, and the fibers f2 are densely present. Therefore, the gaps g2 between the fibers f2 constituting the non-skin side portion 22 are smaller than the gaps g1 between the fibers f1 constituting the skin side portion 21. Therefore, excreted liquid such as urine excreted on the topsheet 20 is likely to migrate to the non-skin side portion 22 by capillary action after penetrating the skin side portion 21. In other words, the excreted liquid is likely to be drawn into the inside of the topsheet 20.

[0047] The average fineness of fibers f1 and f2 can be compared by a known method. For example, the target topsheet 20 is frozen with liquid nitrogen or the like, and then fibers of a predetermined length (e.g., 5 mm) are cut out from any 10 positions of the skin side portion 21 and the non-skin side portion 22. That is, fibers are cut out from the skin side of the topsheet 20, and fibers are also cut out from the non-skin side of the topsheet 20. The ends of the cut fibers are cut perpendicular to the direction in which the fibers extend. The cut surfaces are photographed at a predetermined magnification, and the fiber diameters (mm) of the fibers are measured from the cross-sectional photograph obtained. The average value of the fiber diameters of the 10 fibers taken out of the skin side portion 21 (skin side) is calculated, and the average value of the fiber diameters of the 10 fibers taken out of the non-skin side portion 22 (non-skin side) is calculated. When the average fiber diameter of the non-skin side portion 22 is smaller than the average fiber diameter of the skin side portion 21, it can be confirmed that the average fineness of the fibers f2 constituting the non-skin side portion 22 is smaller than the average fineness of the fibers f1 constituting the skin side portion 21.

[0048] In addition, the portion of the topsheet 20 composed of fibers f1 with a thick average fiber diameter is referred to as the skin side portion 21, and the portion composed of fibers f2 with a thin average fiber diameter is referred to as the non-skin side portion 22. The thicknesses of the skin side portion 21 and the non-skin side portion 22 may be the same or different. Furthermore, at the boundary between the skin side portion 21 and the non-skin side portion 22, thick fibers f1 and thin fibers f2 are mixed. Therefore, the center position in the thickness direction of the region where fibers of different thicknesses are mixed is taken as the boundary, and the portion on the skin side of the boundary is referred to as the skin side portion 21, and the portion on the non-skin side of the boundary is referred to as the non-skin side portion 22.

[0049] Moreover, it is preferable that the fibers f1, f2 constituting the skin side portion 21 and the non-skin side portion 22, respectively, contain thermoplastic fibers. In that case, in the manufacturing process of the topsheet 20, heat is applied to the laminated fibers (fiber web), whereby some of the fibers are thermally fused together to form a sheet.

[0050] Examples of thermoplastic fibers include fibers formed from polyolefin polymers such as polyethylene and polypropylene, polyester polymers such as polyethylene terephthalate (PET), polybutylene terephthalate, and polypentylene terephthalate, polyamide polymers such as nylon 6 and nylon 6,6, acrylic polymers, polyacrylonitrile polymers, or modified products thereof, or combinations thereof.

[0051] 7 and 8, the absorbent core 121 has compressed portions 123 compressed from the skin side in the thickness direction. The compressed portions 123 are not compressed over the entire plane of the absorbent core 121 (so-called flat press), but are portions of the absorbent core 121 that are partially compressed. Note that the topsheet 20 in Fig. 8 is also illustrated flat, not with an uneven shape, for ease of understanding.

[0052] In the compressed portions 123, the absorbent core 121 is recessed toward the non-skin side in the thickness direction, and the density of the fibers constituting the absorbent core 121 is higher than in the surrounding area. Therefore, after the excreted liquid falls into the recessed compressed portions 123, it is easily drawn into the absorbent core 121 (to the non-skin side in the thickness direction) by capillary action.

[0053] Furthermore, in the diaper 1 of this embodiment, when 40 ml of artificial urine is dropped four times onto a predetermined position p0 on the top sheet 20, and then a "drainage test" is performed to determine a drainage index related to the absorption rate and absorption amount of artificial urine based on the measurement results of the predetermined position p0 using a moisture meter, the drainage index is 50% or less.

[0054] The predetermined position p0 is a position shifted 50 mm toward the ventral side (front side) from the center line CL that divides the diaper 1 in the longitudinal direction in an unfolded and stretched state as shown in Fig. 2. It is also a position on the center line that divides the absorbent core 121 in the width direction. In other words, the predetermined position p0 is a position that comes into contact with the wearer's urinary excretion opening or its vicinity. Therefore, the drainage test is a test that simulates a state in which 40 ml of urine is excreted from the wearer's excretion opening toward the topsheet 20 four times.

[0055] The moisture meter measures the amount of moisture from the skin-facing side of the topsheet 20, and the measurement result corresponds to the amount of artificial urine remaining on the topsheet 20. A decrease in the moisture meter measurement result indicates that the amount of artificial urine on the topsheet 20 has decreased and the artificial urine has been drawn into the diaper 1. As shown in FIG. 9, the moisture meter measurement value rises sharply immediately after the artificial urine is dripped, and then the moisture meter measurement value gradually decreases, indicating that the artificial urine has been drawn into the diaper 1. In other words, a small moisture meter measurement result indicates that a small amount of artificial urine remains on the topsheet 20 and that the topsheet 20 is dry.

[0056] The drainage index is the ratio of the area A1 of the shaded area (change in moisture content) surrounded by the moisture meter measurement results when artificial urine is dropped for the fourth time, to the area A0 of the rectangle (maximum moisture content), as shown in Figures 10A and 10B. Drainage index (%) = A1 / A0 x 100

[0057] Specifically, the minimum value W0 (i.e., the measurement at time t4) and maximum value W1 (i.e., the measurement immediately after the end of dripping) of the moisture meter are obtained during the five minutes (300 seconds) from when the fourth drip of artificial urine began (t4). The maximum amount Wx (=W1-W0) is calculated by subtracting the minimum value W0 from the maximum value W1. The area A0 of the rectangle (maximum moisture amount) is calculated as Wx x 300 (seconds). The area A1 of the shaded area (change in moisture amount) is the area enclosed by the minimum value W0 of the moisture meter measurement and the moisture meter measurement result during the five minutes from when the fourth drip of artificial urine began (t4) (the integrated value of the measurement value relative to the minimum value W0).

[0058] If the artificial urine is not drawn into the diaper 1 during the five minutes from time t4 and the moisture meter measurement result remains at the maximum moisture content Wx, the area A1 will remain almost the same as the area A0 and the drainage index will be close to 100%. On the other hand, if the amount of artificial urine on the topsheet 20 decreases and the moisture meter measurement result decreases, the area A1 of the shaded area will decrease and the drainage index will also decrease. In other words, the drainage index represents the amount of artificial urine absorbed from the topsheet 20, and it can be seen that the smaller the drainage index, the greater the amount absorbed.

[0059] The slope of the moisture meter measurement results (graph) represents the rate at which the artificial urine on the topsheet 20 is reduced, i.e., the rate at which it is absorbed into the diaper 1. The greater the slope, the faster the absorption rate, and the moisture meter measurement result decreases early in the five minutes from time t4. In this case, the area A1 of the shaded area also decreases, and the drainage index also decreases. In other words, the drainage index represents the absorption rate of the artificial urine from the topsheet 20, and it can be seen that the smaller the drainage index, the faster the absorption rate.

[0060] Therefore, the diaper 1 of the present embodiment, which has a drainage index of 50% or less, absorbs excreted liquid faster and in larger amounts than diapers with a drainage index of more than 50%. This makes it difficult for excreted liquid to remain on the topsheet 20, and the topsheet 20 (skin side) is highly dry. In particular, when the wearer is an infant, the amount of excretion per time is small (around 40 ml). Therefore, even when excretion is repeated (even when excretion is performed four times), the topsheet 20 is likely to remain dry.

[0061] As described above, in the diaper 1 of this embodiment, the gaps g2 between the fibers f2 constituting the non-skin side portion 22 are small, and excreted liquid is easily drawn into the topsheet 20. Furthermore, in the compressed portions 123, excreted liquid is easily drawn into the absorbent core 121. Furthermore, the drainage index is 50% or less, and the excreted liquid is absorbed quickly from the topsheet 20 and in a large amount.

[0062] Therefore, excreted liquid is less likely to remain on the topsheet 20, and the topsheet 20 (the skin side of the diaper 1) remains dry. This prevents the wearer from feeling uncomfortable due to a wet topsheet, and improves the comfort of the diaper 1. In addition, liquid is less likely to migrate from the non-skin side portion 22, which has a smaller gap g2, to the skin side portion 21, which has a larger gap g1. This prevents excreted liquid absorbed by the absorber 12 from returning (rewetting) onto the topsheet 12, and the dryness of the topsheet 20 is maintained.

[0063] A liquid drainage test was actually conducted on a diaper 1 of the present embodiment (Example) and a conventional pants-type diaper for infants (Comparative Example) that has been commercially available. The results are shown in Figures 9, 10A, and 10B. The diaper 1 of the Example and the diaper of the Comparative Example have different topsheet configurations, and the absorbent core of the diaper of the Comparative Example does not have compressed portions.

[0064] The test method for the "liquid drainage test" is as follows: Figure 11 is an explanatory diagram of a jig 50 on which the diaper 1 is placed. The moisture meter used was a fiber-type infrared moisture meter (Fujiwork Corp.'s "IM-3SRV MODEL-1000H (high moisture measurement type)" or an equivalent. The artificial urine was prepared by dissolving 200g of urea, 80g of sodium chloride, 8g of magnesium sulfate, 3g of calcium chloride, and approximately 1g of dye: Blue No. 1 in 10L of ion-exchanged water, so that the surface tension was 50-55mN / m. A water bath was used to ensure that the temperature of the artificial urine was approximately 37°C when it was dropped.

[0065] (1) First, a sample of the absorbent article to be measured is placed with the skin side facing up in an unfolded and stretched state as shown in Figure 2. The artificial urine drop position p0 (predetermined position) on the sample is identified. As mentioned above, the drop position p0 (predetermined position) is the center position in the width direction, 50 mm forward from the center CL in the longitudinal direction of the product.

[0066] In the case of a sample having a leak-proof wall portion 15, a part of the leak-proof wall portion 15 may be cut out. The diaper 1 is placed on a surface that is gently curved downward in a U-shape, not on a flat surface, using a jig 50 shown in FIG. 11. The vertical length of the placement surface of the jig 50 is 450 mm, and the horizontal length is 125 mm. The placement surface is mainly inclined in an area about 1 / 3 inward from both vertical ends of the jig 50, and the height difference between the vertical ends and the center is 65 mm. The diaper 1 in the unfolded state is placed so that its longitudinal center is aligned with the vertical center of the jig 50.

[0067] (2) Next, fix the artificial urine dripping part of the liquid delivery pump (Digital Liquid Delivery Pump Master Flex L / S Model No. 7550-30 manufactured by Yamato Scientific Co., Ltd., or equivalent) at a position 10 mm above the sample. Since the artificial urine is dripped in four separate batches, the thickness of the sample being measured at the dripping position p0 is determined using a laser thickness meter (for example, CMOS Laser Applisensor IL Series manufactured by Keyence Corporation), and the height of the liquid delivery pump is adjusted so that the dripping part of the liquid delivery pump relative to the sample is constant (10 mm above).

[0068] (3) Then, 10 seconds after the PC starts acquiring the moisture meter's measurement results, the first drip begins. The artificial urine is automatically dripped using the liquid delivery pump. The amount of each drip is 40 ml, and the drip rate is 480 ml / min.

[0069] (4) After that, the next drip of artificial urine begins 5 minutes after the start of the previous drip. The artificial urine is dripped 4 times at 5-minute intervals. Then, the change in the moisture meter measurement results over time (graph) is obtained.

[0070] (5) The above measurements are carried out multiple times for each sample, and multiple measurement results are obtained using the moisture meter. The average of the multiple measurement results is calculated. The drainage index is calculated from the average result (graph) as shown in Figure 10.

[0071] Fig. 9 shows the average value of four measurements for the diaper 1 of the embodiment (solid line graph) and the average value of four measurements for the diaper of the comparative example (dotted line graph). Furthermore, the measurement results after the fourth drop of artificial urine from the measurement results in Fig. 9 are shown in Figs. 10A and 10B.

[0072] 9, it can be seen that after the first drop of artificial urine, in both the Example and the Comparative Example, the moisture meter measurement value immediately dropped, the amount of liquid on the topsheet 20 decreased, and the artificial urine was absorbed into the interior of the diaper. However, as the number of drops increased to the second and third times, in the Comparative Example, the rate at which the moisture meter measurement value dropped was slower than in the Example, and it can be seen that the rate at which the artificial urine was absorbed into the interior of the diaper decreased.

[0073] Based on the measurement results after the fourth drop, the drainage index of each of the diapers of the Example and the Comparative Example was calculated. The drainage index of the Example was 38%, and the drainage index of the Comparative Example was 68%. This is because the comparative example had a slower dripping speed of the artificial urine after the fourth drop, and the moisture meter measurement value was high even after 5 minutes had passed, and a large amount of artificial urine remained on the topsheet, compared to the Example. Thus, the drainage index of the diaper 1 of this embodiment was 50% or less, and the absorption speed after 40 ml of excreted liquid was dripped four times was faster and the absorption amount was larger than that of the comparative example diaper with a drainage index higher than 50%. Therefore, the dryness of the topsheet 20 of the diaper 1 of this embodiment is improved.

[0074] It is also preferable that the skin side portion 21 of the topsheet 20 has a higher longitudinal breaking strength than the non-skin side portion 22. This makes the skin side portion 21 less likely to be crushed in the thickness direction, while the non-skin side portion 22 is more likely to be crushed in the thickness direction.

[0075] 6A and 6B, when the wearer's body pressure is applied while wearing the diaper 1, the thickness of the non-skin side portion 22 is likely to become smaller than that before wearing (ta>tb). In this case, in addition to the small fiber diameter of the non-skin side portion 22, the gaps g2 between the fibers become smaller due to crushing. This facilitates capillary action, and excreted liquid on the topsheet 20 is more likely to migrate from the skin side portion 21 to the non-skin side portion 22, improving the dryness of the topsheet 20.

[0076] On the other hand, the skin side portion 21 is less crushed when body pressure is applied, and the thickness is likely to be maintained even when worn. Therefore, the excreted liquid absorbed by the absorber 12 is unlikely to flow back onto the topsheet 20, and the dryness of the topsheet 20 is likely to be maintained.

[0077] The breaking strength of the skin side portion 21 and the non-skin side portion 22 can be compared by a known method. For example, it can be confirmed by the degree of fiber collapse when the surface is rubbed. First, a sample of a predetermined size (e.g., 300 mm long x 100 mm wide) is cut out from the target topsheet 20. Two samples are prepared, one for the skin side portion 21 and one for the non-skin side portion 22. The sample is fixed on the measurement stage of a dyed material friction fastness tester (e.g., manufactured by Daiei Kagaku Seiki Seisakusho Co., Ltd. or an equivalent). When measuring the skin side portion 21, the topsheet 20 is fixed on the stage with the skin side facing up, and when measuring the non-skin side portion 22, the topsheet 20 is fixed on the stage with the non-skin side facing up. Next, a 300 g weight is attached to the upper surface of the friction terminal of the dyed part friction fastness tester, and a cloth tape forming a friction surface is attached to the lower surface. Next, the surface of the sample fixed on the stage is rubbed with the friction surface of the friction terminal. At this time, a predetermined length (e.g., 100 mm) is rubbed in the direction corresponding to the longitudinal direction of the diaper 1, and the friction terminal is moved back and forth 50 times. Then, the fluffing state of the sample surface after rubbing with the friction terminal is observed. If the fluffing is greater on the skin side than on the non-skin side, it can be confirmed that the skin side portion 21 has a higher breaking strength than the non-skin side portion 22.

[0078] Alternatively, the comparison may be made based on the strength reduction rate. A total of three types of samples are prepared: a sample before the friction fastness test, a sample after the friction fastness test on the skin side, and a sample after the friction fastness test on the non-skin side. Each sample with a width of 50 mm is set in a tensile tester (chuck distance is 50 mm) and pulled at a speed of 100 mm / min to measure the maximum strength. The strength of each sample after the friction fastness test on the skin side or non-skin side is compared, with the strength of the sample before the friction fastness test being taken as 100%. The strength reduction rate is calculated according to the formula: sample strength after friction fastness ÷ sample strength before friction fastness × 100. If the strength reduction rate of the sample with the skin side rubbed is greater than the strength reduction rate of the sample with the non-skin side rubbed, it can be confirmed that the skin side portion 21 has a higher breaking strength than the non-skin side portion 22.

[0079] It is also preferable that the total length of the fibers constituting the non-skin side portion 22 of the topsheet 20 is longer than the total length of the fibers constituting the skin side portion 21.

[0080] By making the total length of the fibers constituting the non-skin side portion 22 long, the gaps g2 between the more fibers f2 become narrower when the wearer's body pressure is applied. This improves the ability to draw excreted liquid from the skin side portion 21 to the non-skin side portion 22, improving the dryness of the topsheet 20. Furthermore, if the total fiber length of the non-skin side portion 22 is long and the amount of fiber in the non-skin side portion 22 is large, the thickness of the non-skin side portion 22 can be prevented from becoming too thin even when body pressure is applied. This ensures the bulk of the non-skin side portion 21, which is the area where capillary action works, and maintains the ability to draw excreted liquid when worn.

[0081] The comparison of the total length of the fibers constituting the skin side portion 21 and the non-skin side portion 22 can be confirmed by a known method. For example, the topsheet 20 is cut in the width direction at a number of arbitrary positions in the longitudinal direction. Next, an optical microscope (e.g., Keyence Digital Microscope VHX-7000 or equivalent) is used to enlarge and photograph the cut surface. In each of the photographed cross-sectional images, a region where thick fibers exist, a region where thin fibers exist, and a region where fibers of different thicknesses are mixed are identified. The center position in the thickness direction of the region where fibers of different thicknesses are mixed is identified, and the part on the skin side of the center position is defined as the skin side portion 21, and the part on the non-skin side of the center position is defined as the non-skin side portion 22. Then, if the number of fiber cross sections is greater in the non-skin side portion 22 than in the skin side portion 21 in the multiple cross-sectional images, it can be confirmed that the total length of the fibers constituting the non-skin side portion 22 is longer.

[0082] 4, the diaper 1 has a skin-side core wrap sheet 122 adjacent to the non-skin side in the thickness direction of the topsheet 20. It is preferable that the hydrophilicity of the skin-side surface of this core wrap sheet 122 is higher than the hydrophilicity of the skin-side surface of the topsheet 20.

[0083] By doing so, excreted liquid is more likely to migrate from the top sheet 20 to the sheet with higher hydrophilicity (here, the core wrap sheet 122). Therefore, the excreted liquid migrates successively from the top sheet 20 to the sheet with higher hydrophilicity, and the excreted liquid is less likely to remain on the top sheet 20. This improves the dryness of the top sheet 20. However, without being limited to the above, the hydrophilicity of the skin side surface of the core wrap sheet 122 may be lower than the hydrophilicity of the skin side surface of the top sheet 20.

[0084] The hydrophilicity of a sheet means that liquid spreads easily on the surface of the sheet and the surface of the sheet has a contact angle of 90° or less. The contact angle is the angle between the horizontal plane and the tangent to the contour curve of the water (droplet) at the intersection of the contour curve and the horizontal plane when water is dropped onto the surface of the sheet (horizontal plane).

[0085] The hydrophilicity can be measured by a known method. For example, the target top sheet 20 and sheet (core wrap sheet 122) are taken out of the diaper 1. A droplet of ion-exchanged water is attached to the skin side of each sheet, the droplet is recorded, and the contact angle is measured based on the recorded image. More specifically, a microscope VHX-1000 manufactured by Keyence Corporation or an equivalent device is used as the measuring device, and a medium-magnification zoom lens is attached in a state inclined at 90°. The sheet is set on the measuring stage of the measuring device so that the skin side of the sheet faces upward, a droplet of 3 μL of ion-exchanged water is attached, and the image of the droplet is recorded and taken into the measuring device. Of the multiple recorded images, 10 images with clear edges of the droplet are selected, and the contact angle of the droplet is measured for each of the 10 images, and the average of these contact angles is taken as the contact angle of each sheet. The measuring environment is 20°C / 50% RH.

[0086] As shown in FIG. 5A, the topsheet 20 of this embodiment is unevenly shaped, and both the skin side and the non-skin side have an uneven shape. The convex portions 23 protruding toward the skin side of the skin side of the topsheet 20 extend in the longitudinal direction, and a plurality of the convex portions 23 are arranged in the width direction. Between the convex portions 23, a concave portion 24 extending in the longitudinal direction is formed. In the concave portion 24, a second concave portion 25 that is further recessed toward the non-skin side than the concave portion 24 is formed. As shown in FIG. 5B, the second concave portions 25 are formed at a predetermined interval in the longitudinal direction in the concave portion 24. Such a topsheet 20 can be formed, for example, by passing the topsheet 20 between a pair of heating pattern rollers having concaves and convexes formed on the outer peripheral surface according to the concave-convex pattern of the topsheet 20.

[0087] By forming the uneven shape on the skin side of the topsheet 20 in this way, the contact area between the wearer and the topsheet 20 can be reduced. In the diaper 1 of this embodiment, the dryness on the topsheet 20 is improved, but by reducing the contact area between the wearer and the topsheet 20, the wearer is even less likely to feel the wetness of the diaper 1. In addition, since body pressure is less likely to be applied to the entire topsheet 20, excreted liquid absorbed by the absorbent core 121 is less likely to flow back onto the topsheet 20. In addition, a passage for moist air is formed in the recesses 24, and the breathability of the diaper 1 is also improved. Therefore, the comfort of wearing the diaper 1 is improved.

[0088] In addition, even if the wearer's body pressure is applied and the protrusions 23 are crushed, the second recesses 25 are unlikely to come into contact with the wearer's skin. Therefore, by providing the topsheet 20 with the second recesses 25, the contact area between the wearer and the topsheet 20 can be more reliably reduced.

[0089] Furthermore, excreted liquid excreted on the topsheet 20 is dispersed in the longitudinal direction by the recesses 24 and is drawn into the inside of the topsheet 20. This allows the diaper 1 to be effectively utilized in the planar direction.

[0090] Further, through holes 26 are provided on the side surfaces of the second recesses 25. Such through holes 26 can be formed, for example, by creating a height difference between the protrusions 23 and the second recesses 25 when the topsheet 20 is shaped to have projections and recesses. In this manner, the topsheet 20 preferably has through holes 26 penetrating in the thickness direction of the topsheet 20. This allows excreted liquid excreted on the topsheet 20 to easily migrate from the through holes 26 to the inside of the diaper 1 (the absorbent body 12). Therefore, excreted liquid is less likely to remain on the topsheet 20, improving the dryness of the topsheet 20.

[0091] However, the configuration of the top sheet 20 is not limited to the above. Fig. 12A and Fig. 12B are explanatory diagrams of modified examples of the top sheet 20. For example, as shown in Fig. 12A, the skin side (skin side portion 21) of the top sheet 20 may have an uneven shape, while the non-skin side (non-skin side portion 22) may have a flat shape. Also, as shown in Fig. 12B, the top sheet 20 may have a flat shape without having an uneven shape. Also, the through hole 26 in Fig. 5A penetrates the wall portion surrounding the second recess 25 in the width direction of the diaper 1. However, as shown in Fig. 12B, the top sheet 20 may have a through hole 26 penetrating along the thickness direction of the diaper 1.

[0092] The absorbent core 121 is provided with compressed portions 123, which preferably extend linearly as shown in Figs. 7A and 7B. The compressed portions 123 extending linearly may be a plurality of dot-like compressed portions arranged linearly, or may be continuously compressed groove-like. In this case, the excreted liquid is likely to spread along the compressed portions 123, and spreads in the planar direction of the absorbent core 121. Therefore, the excreted liquid that has migrated from the topsheet 20 to the absorbent core 121 is drawn into the absorbent core 121 while spreading along the compressed portions 123. By the excreted liquid gradually moving inside the diaper 1 in this way, the excreted liquid is unlikely to remain on the topsheet 20, and the dryness of the topsheet 20 is improved. In addition, the absorbent core 121 can be effectively utilized in the planar direction, and the amount of excreted liquid that can be absorbed by the absorbent core 121 is increased. Therefore, even when multiple excretions are made or a large amount of excreted liquid is excreted, the surface of the topsheet 20 tends to remain dry.

[0093] However, the absorbent core 121 may have a plurality of discretely arranged dot-like compressed portions 123. In this case, too, excreted liquid is easily drawn into the absorbent core 121 densified by the compressed portions 123. In addition, in FIG. 7A, a plurality of linear compressed portions 123 extending in the longitudinal direction while meandering in the width direction are arranged in the width direction. In FIG. 7B, a plurality of linear hexagonal compressed portions 123 are arranged in the longitudinal direction and the width direction. However, the shape, arrangement, number, etc. of the illustrated compressed portions 123 are merely examples and are not particularly limited. For example, in FIG. 7A, the compressed portions 123 are arranged over the entire plane of the absorbent core 121, but the compressed portions 123 may be arranged in a part of the plane of the absorbent core 121.

[0094] In addition, the compressed portions 123 formed on the absorbent core 121 of this embodiment compress the core wrap sheet 122 on the skin side and the absorbent core 121 from the skin side, as shown in FIG. 8A, but do not compress the topsheet 20.

[0095] In this case, the top sheet 20 and the skin-side core wrap sheet 122 are not in close contact with each other, and gaps are likely to form between them. Excrement is likely to be temporarily stored in the gaps, and excrement absorbed by the absorbent core 121 is unlikely to flow back onto the top sheet 20. This makes it easier to maintain the dryness of the top sheet 20. Furthermore, since the top sheet 20 does not have the compressed portions 123, which are dense and relatively hard, the top sheet 20 feels soft against the skin. This improves the comfort of the diaper 1 when worn.

[0096] As described above, the multiple protrusions 23 extending in the longitudinal direction are arranged at intervals in the width direction on the skin side of the topsheet 20. This makes it possible to reduce the contact area between the topsheet 20 and the wearer and to diffuse excretory fluid in the longitudinal direction.

[0097] In addition, a user of the diaper 1 (a parent or guardian, etc.) may touch the topsheet 20 of the diaper 1 after use along the longitudinal direction with their hands to check the dryness of the topsheet 20. In this case, the topsheet 20 has longitudinally extending irregularities and the topsheet 20 does not have compressed portions 123, which allows the user's fingers to move smoothly. This makes it easier for the user to recognize that the product has a high level of dryness on the topsheet 20. In particular, in the case of a diaper 1 for infants and toddlers, parents or guardians do not actually wear the diaper, so being able to confirm that the diaper has a high level of dryness allows them to have their child wear it with peace of mind.

[0098] However, without being limited to the above, as shown in Fig. 8B, the compressed portions 123 may compress the topsheet 20 together with the absorbent core 121. In this case, excreted liquid discharged onto the topsheet 20 tends to fall into the compressed portions 123, and then, due to the capillary phenomenon of the densified compressed portions 123, the excreted liquid tends to be drawn into the inside of the absorbent core 121. This improves the dryness of the topsheet 20. Furthermore, since the topsheet 20 is compressed, the visibility of the compressed portions 123 is improved. This makes it easier for the user to recognize that the product is one that easily absorbs excreted liquid.

[0099] Alternatively, the compression section 123 may only compress the absorbent core 121 without compressing the core wrap sheet 122. In addition, although a portion of the absorbent core 121 in the thickness direction is compressed in Fig. 8A etc., the entire area of ​​the absorbent core 121 in the thickness direction may be compressed.

[0100] In addition, it is preferable that the skin side portion 21 of the topsheet 20 has a high basis weight region 21H having a high fiber basis weight and a low basis weight region 21L having a lower fiber basis weight than the high basis weight region 21H. This makes it possible to increase the fiber density of the high basis weight region 21H and to increase the thickness of the high basis weight region 21H. Meanwhile, excreted liquid can be quickly dropped into the low basis weight region 21L where the gaps between the fibers are large.

[0101] For example, in the topsheet 20 of this embodiment, as shown in Fig. 5A, the high basis weight regions 21H of the skin side portion 21 are located at the convex portions 23, and the low basis weight regions 21L of the skin side portion 21 are located at the concave portions 24. When the high basis weight regions 21H and the low basis weight regions 21L have the same thickness, the fiber density of the high basis weight regions 21H is higher than that of the surrounding areas. Therefore, excreted liquid can be drawn into the topsheet 20 from the high basis weight regions 21H by capillary action, and excreted liquid is less likely to remain on the topsheet 20.

[0102] Furthermore, when the densities of the high basis weight region 21H and the low basis weight region 21L are the same, the thickness of the high basis weight region 21H can be made thicker, as shown in Fig. 12A. This allows the skin side surface of the skin side portion 21 to have an uneven shape, thereby reducing the contact area with the wearer.

[0103] 5A and 12A, it is preferable that the high basis weight region 21H protrudes further toward the skin side than the low basis weight region 21L. This allows the surface area of ​​the topsheet 20 facing the skin to be uneven. This reduces the contact area between the topsheet 20 and the wearer, making the wearer less likely to feel the wetness of the diaper 1. In addition, since body pressure is less likely to be applied to the entire topsheet 20, excreted liquid absorbed by the absorbent core 121 is less likely to flow back onto the topsheet 20.

[0104] Whether the skin side portion 21 has the high basis weight region 21H and the low basis weight region 21L can be confirmed by a known method, for example, by observing a cross section of the topsheet 20 cut in the width direction under magnification with an optical microscope or the like.

[0105] Furthermore, when a test is conducted to measure the amount of rewet of artificial urine returning to the topsheet 20 when 40 ml of artificial urine is dropped onto the topsheet 20 four times, it is preferable that the rewet amount is 1.0 g or less. This makes it easier to maintain the dryness of the topsheet 20 compared to when the rewet amount is more than 1.0 g, and therefore improves the comfort of the diaper 1 when worn.

[0106] The rewetting amount can be measured by the following test method. First, a sample (diaper 1) in an unfolded and stretched state is fixed with the skin side facing up. In the case of a sample having a leakage prevention wall portion 15 or the like, a part of the leakage prevention wall portion 15 may be cut out so that a filter paper can be placed thereon. In addition, the weight w0 (g) of about 50 g of filter paper (for example, Advantec Qualitative Filter Paper No. 2, manufactured by Toyo Roshi Co., Ltd.) is measured. Next, the position where the artificial urine was dropped on the sample was identified. The dropping position was the center in the width direction of the sample, which was 70 mm forward from the center in the longitudinal direction. Next, set the dropping device (burette or liquid pump (e.g., the one used in the drainage test or equivalent) so that the dropping part is 10 mm above the dropping position of the sample. Also, place a hollow cylinder (inner diameter 60 mm, 55 g) on ​​the sample while aligning the center of the hollow cylinder with the dropping position of the sample. Next, 40 ml of artificial urine is dripped 4 times at 10-minute intervals. The drip rate is 40 ml / 5 seconds. The artificial urine is the same as that described in the drainage test. Then, 5 minutes after the start of the fourth drip of artificial urine, place the filter paper on the sample while aligning the center position of the filter paper whose weight was measured with the sample drip position, and place a weight (flat size 10 cm x 10 cm, 3.5 kg) on ​​top of it. 3 minutes after placing the weight, remove it and measure the weight w1 (g) of the filter paper. The weight of the filter paper before the test (w0) is subtracted from the weight of the filter paper after the test (w1), and this value is regarded as the rewet amount (=w1-w0).

[0107] A rewetting test was conducted on the diaper 1 of the example and the diaper of the comparative example that had been subjected to the drainage test. As a result, the rewetting amount of the diaper of the comparative example was 2.5 g, whereas the rewetting amount of the diaper 1 of the example (present embodiment) was 0.5 g. Therefore, it was found that the diaper 1 of the present embodiment, which has a rewetting amount of 1.0 g or less, is more likely to maintain dryness on the topsheet 20 than the diaper of the comparative example.

[0108] The above-mentioned embodiment is for the purpose of facilitating understanding of the present invention, and is not intended to limit the present invention. The present invention can be modified or improved without departing from the spirit of the present invention, and it goes without saying that the present invention includes equivalents thereof. [Explanation of symbols]

[0109] 1. Pants-type disposable diapers (absorbent articles), 2 side joints, 10 Absorbent body, 12 absorber, 121 absorbent core, 122 core wrap sheet, 123 Pressing section, 13 Back seat, 15 leak-proof wall portion, 16 leak-proof wall elastic member, 17 Leg elastic member, 20 Surface sheet, 21 Skin side, 21H high basis weight area, 21L low basis weight area, 22 Non-skin side, 23 convex portion, 24 concave portion, 25 second recess, 26 through hole, 30 front waist portion, 31 skin side sheet, 32 non-skin side sheet, 33 waist elastic member, 34 cover sheet, 40 rear waist portion, 41 skin side sheet, 42 non-skin side sheet, 43 waist elastic member, 44 cover sheet, 50 fixtures,

Claims

1. In a deployed state, the device has a longitudinal direction, a width direction, and a thickness direction which are perpendicular to each other, An absorbent article having an absorbent core and a top sheet, the topsheet has a skin side portion located on the skin side in the thickness direction, and a non-skin side portion located on the non-skin side in the thickness direction relative to the skin side portion, the average fineness of the fibers constituting the non-skin side portion is smaller than the average fineness of the fibers constituting the skin side portion; The absorbent core has a compressed portion compressed from the skin side in the thickness direction, An absorbent article characterized in that, when 40 ml of artificial urine is dropped onto a predetermined position on the top sheet four times, and then a drainage test is performed to determine a drainage index relating to the absorption rate and absorption amount of the artificial urine based on the measurement results of the predetermined position using a moisture meter, the drainage index is 50% or less.

2. The absorbent article according to claim 1, An absorbent article, characterized in that the skin side portion of the topsheet has a higher breaking strength in the longitudinal direction than the non-skin side portion.

3. The absorbent article according to claim 1 or 2, An absorbent article, characterized in that a total length of the fibers constituting the non-skin side portion of the topsheet is longer than a total length of the fibers constituting the skin side portion of the topsheet.

4. The absorbent article according to claim 1 or 2, a sheet adjacent to the non-skin side of the top sheet in the thickness direction, The absorbent article is characterized in that the hydrophilicity of the skin side surface of the sheet is higher than the hydrophilicity of the skin side surface of the top sheet.

5. The absorbent article according to claim 1 or 2, An absorbent article, wherein the compression section does not compress the top sheet.

6. The absorbent article according to claim 5, An absorbent article, characterized in that a plurality of protrusions extending in the longitudinal direction are arranged at intervals in the width direction on the skin side of the topsheet.

7. The absorbent article according to claim 1 or 2, An absorbent article, characterized in that the compression section compresses the top sheet together with the absorbent core.

8. The absorbent article according to claim 1 or 2, An absorbent article, wherein the top sheet has through holes passing through the top sheet in a thickness direction.

9. The absorbent article according to claim 1 or 2, An absorbent article characterized in that the skin side portion of the topsheet has a high basis weight region in which the basis weight of the fibers is high and a low basis weight region in which the basis weight of the fibers is lower than that of the high basis weight region.

10. 10. The absorbent article of claim 9, The absorbent article is characterized in that the high basis weight region protrudes closer to the skin than the low basis weight region.

11. The absorbent article according to claim 1 or 2, An absorbent article characterized in that, when a test is conducted to measure the amount of rewet of the artificial urine returning to the top sheet when 40 ml of artificial urine is dropped onto the top sheet four times, the rewet amount is 1.0 g or less.

Images