JP7572913B2 - Absorbent articles - Google Patents

Description

The present invention relates to absorbent articles such as disposable diapers, urine pads, incontinence pads, and sanitary napkins.

2. Description of the Related Art Absorbent articles such as disposable diapers generally include a sheet that comes into contact with the skin of a wearer. From the viewpoints of skin feel, breathability, and the like, there are known absorbent articles in which an uneven shape is formed on the skin-facing surface of the sheet.
For example, Patent Document 1 describes an absorbent article in which a top sheet formed by laminating a first layer and a second layer has first compressed recesses arranged in a predetermined pattern and raised portions formed by the first layer, and second compressed recesses are formed in the raised portions that do not reach the second layer.

The applicant has previously proposed an absorbent article in which a top sheet including a laminate of a first nonwoven fabric and a second nonwoven fabric has a plurality of fused portions where the first nonwoven fabric and the second nonwoven fabric are fused to each other at the periphery of the openings, and a plurality of protruding portions where the first nonwoven fabric protrudes away from the second nonwoven fabric at locations other than the fused portions, and the fused portions have a plurality of protrusions protruding toward the sublayer, so that when the top sheet is pressed against the sublayer, the protrusions partially press the sublayer (Patent Document 2).

The applicant has also previously proposed an absorbent article having a non-elastic region where no elastic member is arranged between an elastic region where an elastic member extending in the width direction is arranged and an absorbent core, and the topsheet has a concave-convex region where the convex portions are arranged in a predetermined pattern and continuous vertical grooves and horizontal grooves are formed between the convex portions, at a portion overlapping the non-elastic region, and the vertical grooves meander to a greater extent than the horizontal grooves (Patent Document 3).

JP 2006-263296 A JP 2018-088997 A JP 2019-076499 A

In a sheet having an uneven shape, the larger the convex portion that comes into contact with the wearer's skin, the easier it is to conform to the wearer's skin, and the more comfortable the feel. However, when the convex portion overlaps an elastic member that is stretchable in one direction, the entire convex portion may be crushed by contraction of the elastic member, and the crushed portion may come into close contact with the skin, reducing breathability. Patent documents 1 to 3 do not disclose technology that solves the problem of convex portions being crushed by contraction of the elastic member.

The objective of the present invention is therefore to provide an absorbent article that can effectively prevent the convex portions from collapsing due to contraction of the elastic member without compromising the feel of the convex portions against the skin.

The present invention relates to an absorbent article having an uneven area, comprising a skin-contact sheet in which the uneven area contacts the wearer's skin when worn, and having a vertical direction corresponding to the front-to-back direction of the wearer and a horizontal direction perpendicular to the vertical direction.
It is preferable that the uneven region has a first direction and a second direction perpendicular to the first direction, and has a plurality of convex portions whose length in the first direction is longer than its length in the second direction, and a plurality of concave portions located between the convex portions in the first direction or the second direction.
The recessed portions preferably have low basis weight portions in which the basis weight of the fiber material is smaller than that of the protruding portions.
It is preferable that an elastic member is disposed along a first direction on the non-skin facing side of the skin contact sheet.

The present invention provides an absorbent article that can effectively prevent the convex parts from being crushed due to contraction of the elastic member without compromising the feel of the convex parts against the skin. Such an absorbent article has good breathability.

FIG. 1 is a developed plan view showing a schematic view of the skin-facing side (inner surface side) of a disposable diaper, which is one embodiment of an absorbent article of the present invention, in a developed and stretched state. FIG. 2 is a cross-sectional view taken along line II-II of FIG. FIG. 3 is a plan view showing a top sheet (skin contact sheet) of the disposable diaper of the first embodiment. FIG. 4 is an enlarged plan view showing a part of the concave-convex region P of the skin contact sheet shown in FIG. Figure 5 is a plan view of a convex portion overlapping with an elastic member in the skin contact sheet and a corresponding cross-sectional view, where Figure 5(a) is a view showing the convex portion before deformation, and Figure 5(b) is a view showing the convex portion after deformation. FIG. 6 is a cross-sectional view showing an example of the positional relationship between the concave-convex area of the skin contact sheet and the elastic member. FIG. 7 is a cross-sectional view showing another example of the positional relationship between the concave-convex area of the skin contact sheet and the elastic member. FIG. 8 is a cross-sectional view showing yet another example of the positional relationship between the concave-convex area of the skin contact sheet and the elastic member. FIG. 9 is a diagram showing an example of a cross-sectional structure of a skin contact sheet in still another embodiment. FIG. 10 is a view equivalent to FIG. 4, showing yet another embodiment of the concave-convex region in the skin contact sheet. FIG. 11 is a view equivalent to FIG. 4, showing yet another embodiment of the concave-convex region in the skin contact sheet. FIG. 12 is a view equivalent to FIG. 4, showing yet another embodiment of the concave-convex region in the skin contact sheet. FIG. 13 is a perspective view showing yet another embodiment of the concave-convex region of the skin contact sheet. FIG. 14 is a partially cutaway perspective view showing a stretch sheet that can be used for the elastic member according to the present invention.

Hereinafter, the present invention will be described based on preferred embodiments with reference to the drawings.
1 and 2 show the basic structure of a disposable diaper 1 (hereinafter, simply referred to as diaper 1) which is one embodiment of the absorbent article of the present invention.
As shown in Figures 1 and 2, the diaper 1 comprises a liquid-permeable top sheet 12, a liquid-impermeable back sheet 13, and an absorbent body 14 disposed between the two sheets 12, 13. With respect to the back sheet 13, the concept of liquid impermeability includes poor liquid permeability, and includes cases in which the back sheet 13 does not allow liquid to pass through at all, as well as cases in which the back sheet 13 is made of a water-repellent sheet, etc. As will be described later, the top sheet 12 has uneven areas P, PS on the skin-facing surface, but the unevenness of the uneven areas P, PS is omitted in Figures 1 and 2.

1 is a diagram showing an unfolded and stretched state of a diaper 1. The diaper 1 has a longitudinal direction _X1 corresponding to the front-to-rear direction of a wearer, and a transverse direction _Y1 perpendicular to the longitudinal direction _X1 . The entire length of the diaper 1 in the longitudinal direction _X1 can be divided into three equal parts, an abdominal portion A disposed in front of a wearer when worn, a dorsal portion B disposed behind a wearer when worn, and a crotch portion C located between the abdominal portion A and the dorsal portion B.
The diaper 1 is an open-type disposable diaper, and has fastening tapes 17 provided on both side edges of the back portion B, and a landing zone 18 for fastening the fastening tapes 17 is provided on the outer surface of the abdominal portion A.

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 the influence of the elastic members eliminated). In addition, the "skin-facing side" refers to the side of the diaper or its constituent members (e.g., absorbent body) 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.

The absorbent body 14 in the diaper 1 includes an absorbent core 14a and a core wrap sheet 14b that wraps the absorbent core 14a.
The absorbent core 14a may be made of a laminate of absorbent fibers such as pulp fibers, or a mixed laminate of absorbent fibers and water-absorbent polymers. Examples of absorbent fibers include pulp fibers, rayon fibers, cotton fibers, and hydrophilic cellulose fibers such as cellulose acetate. In addition to hydrophilic cellulose fibers, fibers made of synthetic resins such as polyolefin, polyester, and polyamide that have been hydrophilized with a surfactant or the like may also be used.
The core wrap sheet 14b may be, for example, tissue paper or a water-permeable nonwoven fabric. The core wrap sheet 14b may be a single sheet that wraps the entire absorbent core 14a, or two or more sheets may be combined to wrap the absorbent core 14a. The back sheet 13 may be a liquid-impermeable or water-repellent resin film, a laminate sheet of a resin film and a nonwoven fabric, or the like.

On both sides of the diaper 1 in the longitudinal direction _X1 , a sheet 15 for forming three-dimensional gathers having elastic members 15a for forming three-dimensional gathers is disposed, and when the elastic members 15a for forming three-dimensional gathers are contracted, three-dimensional gathers are formed in the crotch portion C in the worn state, the three-dimensional gathers standing up toward the skin side of the wearer.
In addition, leg elastic members 16 are arranged in a stretched state in the areas around the legs in the crotch portion C, and as they contract, leg gathers are formed in the crotch portion C when worn, which improves the fit around the wearer's legs.
In this embodiment, the stretching directions of the standing gather forming elastic members 15a and the leg elastic members 16 coincide with the longitudinal direction _X1 of the diaper 1.

The diaper 1 of this embodiment has a waist flap portion WF extending outward in the longitudinal direction _X1 from an edge of the absorbent body 4 in the longitudinal direction _X1 at the back side portion B. The waist flap portion WF is a portion made of a member extending outward in the longitudinal direction _X1 from the edge of the absorbent body 4 in the longitudinal direction _X1 . In this embodiment, the waist flap portion WF is made of a sheet 15 for forming three-dimensional gathers extending outward in the longitudinal direction _X1 from the edge of the absorbent body 4, a top sheet 12, and a back sheet 13. These sheets are joined to each other at the extending portions from the edge of the absorbent body 4 by a known joining means such as adhesive, heat sealing, ultrasonic sealing, etc. The waist flap portion WF corresponds to the waist circumference of a wearer when the diaper 1 is worn.

In the diaper 1 of this embodiment, as shown in Fig. 1, waist elastic members 19 are arranged in a stretched state so as to extend in the lateral direction _Y1 in the waist flap portions WF in the back side portion B. Contraction of the waist elastic members 19 forms waist gathers in the portion arranged in the waist portion on the back side of the wearer. In this embodiment, the waist elastic members 19 are fixed in a stretched state along the lateral direction _Y1 between the top sheet 12 and the back sheet 13 in the waist flap portions WF. The diaper 1 may have the waist elastic members 19 in the waist flap portions WF in the abdominal side portion A. In this embodiment, the stretch direction of the waist elastic members 19 coincides with the lateral direction _Y1 of the diaper 1.

The diaper 1 includes a skin contact sheet 10 that contacts the wearer's skin when the diaper is worn. The skin contact sheet 10 has an uneven area in which a plurality of protrusions and recesses are formed, and when the diaper is worn, the uneven area, more specifically, the protrusions contact the wearer's skin.
In the diaper 1 of this embodiment, the topsheet 12 is the skin contact sheet 10, and the skin facing surface of the topsheet 12 has an irregular region.

3, the topsheet 12, i.e., the skin-contact sheet 10, of this embodiment has a central region M located in the center in the lateral direction _Y1 and a pair of side regions S, S located on either side of the central region M. The central region M and the pair of side regions S, S each have an uneven region, and the convex portions and concave portions are formed in different arrangement patterns in both regions M, S. Hereinafter, the uneven region P in the central region M will be referred to as the "central uneven region P," and the uneven region PS in the side region S will be referred to as the "side uneven region PS."

In the skin contact sheet 10 of this embodiment, the central uneven region P has a first direction Y and a second direction X perpendicular to the first direction Y. In this embodiment, the first direction Y coincides with the lateral direction _Y1 of the diaper 1, and the second direction X coincides with the longitudinal direction _X1 of the diaper 1. The central uneven region P is formed throughout the entire central region M.
The central uneven region P has a plurality of convex portions 41 whose length in the first direction Y is longer than that in the second direction X. Hereinafter, the convex portions 41 that are long in the first direction Y are also referred to as "long convex portions 41." The uneven region P may have a plurality of long convex portions 41 and recesses 31 located between the long convex portions 41 in either the first direction Y or the second direction X.

The long convex portion 41 of the present embodiment has a generally rhombus shape in a plan view, with its major axis direction coinciding with the first direction Y and its minor axis direction coinciding with the second direction X.
As shown in FIGS. 3 and 4, in the central concave-convex region P, long convex portions 41 are formed in a dispersed state in the first direction Y and the second direction X.
More specifically, the long protrusions 41 are arranged in a staggered pattern as shown in FIG. 3, and multiple vertical protrusion rows R5, in which multiple long protrusions 41 are lined up along the second direction X, are formed in multiple rows in the first direction Y.
The arrangement positions of the long convex portions 41 of adjacent vertical convex portion rows R5 in the first direction Y are shifted by half a pitch in the second direction X. The long convex portions 41 of adjacent vertical convex portion rows R5 in the first direction Y are arranged such that parts of the long convex portions 41 overlap each other in the second direction X.
The vertical convex portion rows R5, in which the positions of the long convex portions 41 in the second direction X coincide with each other, are formed at equal intervals in the first direction Y. With this configuration, the sizes of the long convex portions 41 and the large concave portions 31 described later can be easily made uniform, and the texture and breathability of the concave-convex region P can be further improved.
In the central uneven region P, a plurality of lateral protrusion rows R6, each having a plurality of long protrusions 41 aligned along the first direction Y, are formed in the second direction X. The lateral protrusion rows R6, in which the positions of the long protrusions 41 in the first direction Y coincide with each other, are formed at equal intervals in the second direction X.

In this embodiment, the central uneven region P has a plurality of recesses 31, 33 located between the long protrusions 41 in the first direction Y and the second direction X. The central uneven region P has two types of recesses 31, 33 of different sizes. Hereinafter, the larger recess 31 will be referred to as the "large recess 31" and the smaller recess 33 will be referred to as the "small recess 33."

In this embodiment, the central uneven region P has a large recess 31 between the edges in the second direction X of the long protrusions 41 in the vertical protrusion row R5 and between the edges in the first direction Y of the long protrusions 41 in the horizontal protrusion row R6.
The large recesses 31 of this embodiment have low basis weight sections 32 in which the basis weight of the fiber material is smaller than that of the long protrusions 41. The low basis weight sections 32 may be low-piling sections in which the basis weight of the fiber material is smaller than that of the long protrusions 41 and in which the fiber material is present, or may be openings penetrating the skin-contact sheet 10 in which no fiber material is present. From the viewpoint of facilitating deformation of the long protrusions 41 described later, it is preferable that the low basis weight sections 32 are the openings.
The large recess 31 of this embodiment has a high density portion 35 in which the fiber material is densified by embossing or the like at the periphery of the low basis weight portion 32 (see the cross-sectional view of FIG. 5(a)). Alternatively, the large recess 31 may not have the high density portion 35 at the periphery of the low basis weight portion 32. The high density portion 35 is omitted in the plan views of FIGS. 4 and 5.

The low basis weight portions 32 formed in the large recesses 31 are also arranged in a staggered pattern as shown in Figures 3 and 4. More specifically, the low basis weight portions 32 are arranged in a plurality of longitudinal low basis weight portion rows R1 aligned along the second direction X and spaced apart from one another in the first direction Y. The positions of the low basis weight portions 32 in the longitudinal low basis weight portion rows R1 adjacent to each other in the first direction Y are shifted by half a pitch in the second direction X.
The multiple longitudinal low basis weight portion rows R1 are formed at equal intervals in the first direction Y. When the low basis weight portions constituting the low basis weight portion rows have different sizes, the interval between the longitudinal low basis weight portion rows R1 in the first direction Y is set to the distance between center lines dividing the longitudinal low basis weight portion rows R1 in half in the first direction Y.
In the central uneven region P, a plurality of lateral low basis weight portion rows R2 are formed in the second direction X, in which a plurality of low basis weight portions 32 are lined up along the first direction Y.
In FIG. 4, the region where the longitudinal low basis weight portion row R1 and the longitudinal protrusion row R5 overlap in the first direction Y is indicated by the symbol f.

In the central uneven region P, the long convex portions 41 and the large concave portions 31 are formed in an alternating arrangement in the first direction Y and the second direction X. That is, a plurality of vertical uneven rows R10 in which the long convex portions 41 and the large concave portions 31 are alternately arranged along the second direction X are formed along the first direction Y.
Furthermore, between adjacent vertical concave-convex rows R10 in the first direction Y, the positions of the long convex portions 41 and the positions of the large concave portions 31 are shifted in the second direction X by half a pitch.

In this embodiment, the central uneven region P has a pair of small recesses 33, 33 on either side of the large recess 31 in the first direction Y, sandwiching the long protrusion 41 in the second direction X. The pair of small recesses 33, 33 are in series along the second direction X, and multiple rows of pairs of small recesses 33, 33 are formed at regular intervals in the first direction Y. The positions of the small recesses 33 that form the rows of pairs of small recesses 33, 33 adjacent to each other in the first direction Y are the same in the second direction X.

In the diaper 1, an elastic member is disposed along the first direction Y on the non-skin facing side of the skin contact sheet 10. In this embodiment, a waist elastic member 19 is disposed in a stretched state along the first direction Y on the non-skin facing side of the skin contact sheet 10, which is the topsheet 12, and the waist elastic member 19 is adapted to exhibit stretchability along the first direction Y.
In the diaper 1 of this embodiment, the central concave-convex region P and the waist elastic member 19 overlap in the waist flap portion WF.

In this embodiment, the long convex portion 41 has a portion a that overlaps with the large recess 31 in the first direction Y (see FIG. 5A). When the waist elastic member 19, which exhibits elasticity in the first direction Y, contracts, the central concave-convex region P is compressed in the first direction Y, and the skin contact sheet 10 is deformed. Specifically, since the large recess 31 is compressed in the first direction Y, the portion a of the long convex portion 41 that overlaps with the large recess 31 in the first direction Y is also compressed in the first direction Y. The long convex portion 41 compressed in the first direction Y is deformed such that the portion a that overlaps with the large recess 31 in the first direction Y is folded inward (see FIG. 5B). Such a deformation due to the contraction of the elastic member is hereinafter also referred to as "inward folding", and the portion that can be folded inward is also referred to as "inward folding portion a".
In this manner, in the diaper 1 of this embodiment, by partially deforming the long convex portions 41, it is possible to effectively prevent the entire convex portions from being crushed due to contraction of the elastic member 19, without impairing the feel against the skin of the long convex portions 41. As a result, the convex shape of the long convex portions 41 is well maintained in the central uneven region P, which prevents the skin contact sheet 10 from coming into close contact with the wearer's skin and also prevents the inside of the diaper 1 from becoming stuffy when worn, thereby providing excellent breathability.
From the viewpoint of further improving the feel and breathability, it is preferable that the long convex portions 41 bend inward when the elastic members 19 contract and return to their original state before the bend when the elastic members 19 expand.

In the central uneven region P of this embodiment, the long convex portions 41 overlap with the longitudinal low basis weight portion row R1 in the first direction Y. The large concave portions 31 have low basis weight portions 32 that are less rigid than other portions. With this configuration, the large concave portions 31 are easily compressed in the first direction Y by contraction of the elastic member 19 (see FIG. 5B). With this compression, the portions a of the long convex portions 41 that overlap with the large concave portions 31 in the first direction Y are also easily compressed in the same direction Y, so that the long convex portions 41 are more likely to bend inward (see FIG. 5B).
In this embodiment, the inwardly folded portion a is located closer to the skin-facing surface than the low basis weight portion 32. In addition, the elastic member 19 is located closer to the non-skin-facing surface than the low basis weight portion 32.

From the viewpoint of improving the breathability inside the diaper 1, it is preferable that the inward folds are generated at multiple long convex portions 41. For example, it is preferable that the uneven region P has multiple regions f in which the longitudinal low basis weight portion row R1 and the longitudinal convex portion row R5 overlap in the first direction Y.

From the viewpoint of easily causing the long convex portion 41 to bend inward, the tensile stress of the elastic member 19 is preferably 8 cN/10 mm or more, more preferably 10 cN/10 mm or more, and also preferably 50 cN/10 mm or less, more preferably 40 cN/10 mm or less, and also preferably 8 cN/10 mm or more and 50 cN/10 mm or less, more preferably 10 cN/10 mm or more and 40 cN/10 mm or less. The tensile stress is measured by the following method.

[Method of measuring tensile stress]
From the diaper in an unfolded and stretched state, a 50 mm-long region of the elastic member that is disposed at a position overlapping the concave-convex region P and that exhibits stretchability in the elastic member is cut out in the stretch direction. The cut-out sample piece is clamped between a pair of chucks in a Tensilon tensile tester ("RTC-1210A" manufactured by ORIENTEC). The distance between the chucks is 10 mm. The sample piece is then stretched at a speed of 50 mm/min until the distance between the chucks becomes 40 mm, and the tensile load (cN/10 mm) is measured when the distance between the chucks is returned to 38 mm. This measurement is repeated three times, and the average of these (the average of the tensile loads when the distance between the chucks is returned to 38 mm) is taken as the extension stress (cN/10 mm).

From the viewpoint of easily causing the long convex portions 41 to fold inward, when the low basis weight portion 32 is a low fiber-stacking portion, the basis weight of the fiber material in the low basis weight portion 32 is preferably within the following range.
The basis weight of the fiber material in the low basis weight portion 32 is preferably 10% or less, and more preferably 20% or less, of the basis weight of the fiber material in the long convex portion 41 .
The basis weight of the fibrous material in the low basis weight portion 32 is preferably 30 g/m ² or less, more preferably 20 g/m ² or less.

The inwardly folded portion a in the inwardly folded long convex portion 41 is formed by a valley portion v that is depressed inside the long convex portion 41 and a peak portion m that is located closer to the skin-facing surface than the valley portion (see FIG. 5(b)). From the viewpoint of making it easier to form the peak portion m, it is preferable that the long convex portion 41 has a portion in which the constituent fibers of the skin-contact sheet 10 are oriented along the second direction X. The portion oriented along the second direction X is less susceptible to a force that compresses the low basis weight portion 32, i.e., a force that contracts in the first direction Y, and therefore it is easier to form the peak portion m in the inwardly folded portion a.
From the viewpoint of making it easier to form the valleys v, it is preferable that the long convex portions 41 have a portion in which the constituent fibers of the skin contact sheet 10 are oriented along the first direction Y. The portion oriented along the first direction Y is more likely to receive a force compressing the low basis weight portion 32, i.e., a force shrinking in the first direction Y, and therefore it is easier to form the valleys v in the inwardly folded portions a.
From the standpoint of making it easier to form the inner fold a, it is preferable that the long convex portion 41 has a portion in which the constituent fibers of the skin-contact sheet 10 are oriented along the first direction Y, and a portion on each side of the portion oriented along the first direction Y in which the constituent fibers are oriented along the second direction X.

The orientation of the fibers in the sheet can be confirmed, for example, by the following method. First, the sheet to be evaluated is removed from the absorbent article by peeling it off using a cold spray or the like. The removed sheet is cut into a rectangular shape in plan view with a length of 2 cm along the second direction X and a length of 2 cm along the first direction Y using a cutter or the like, and this is used as a measurement piece. The measurement piece is cut so that it includes the long convex portion 41. Next, using a microscope (for example, Keyence Corporation's Digital Microscope VHX-1000), the long convex portion of the measurement piece is observed at a magnification of 60 to 200 times. For each of any fibers observed in a certain observation area (for example, 1 mm square), two points are determined at which the length of the fiber is maximum in the area. Next, the angle between the line connecting these two ends and the first direction Y is measured. This measurement is performed for at least three observation areas, and the fiber orientation direction is determined from the arithmetic average value of the angles measured for a total of 30 or more fibers. The fiber orientation direction is determined to be oriented in the first direction Y when the angle with the first direction Y is 45 degrees or less, and is determined to be oriented in the second direction X when the angle with the first direction Y is more than 45 degrees. When measuring fiber orientation, it is preferable to observe at a magnification that allows 10 or more fibers to be confirmed in the region.

From the viewpoint of easily causing the long convex portion 41 to bend inward, it is preferable that the long convex portion 41 satisfies the following formula (1) when the elastic member 19 is maximally stretched.
La>H1...(1)
La: half the length L1 of the long convex portion 41 in the first direction Y; H1: height of the long convex portion 41; The length L1 of the long convex portion 41 in the first direction Y is the maximum length of the long convex portion 41 in the first direction Y (see FIG. 4).
The H1 is measured using a thickness measuring device with a load of 0.05 kPa applied to the skin contact sheet 10. As the thickness measuring device, for example, a laser displacement meter (LK-080, manufactured by KEYENCE Corporation) can be used.

From the same viewpoint as above, when half the length (L1/2) of the long convex portion 41 in the first direction Y is La and the height of the long convex portion 41 is H1 [see FIG. 5(a)], the ratio of La to H1, La/H1, is preferably 1.5 or more, more preferably 2.0 or more, and also preferably 15.0 or less, more preferably 10.0 or less, and also preferably 1.5 or more and 15.0 or less, more preferably 2.0 or more and 10.0 or less.

From the same viewpoint as above, when the length of the long convex portion 41 in the first direction Y is L1 (see FIG. 4) and the length of the long convex portion 41 in the second direction X is L2 (see FIG. 4), the ratio of L1 to L2, L1/L2, is preferably 1.5 or more, more preferably 1.8 or more, and also preferably 5.0 or less, more preferably 3.0 or less, and also preferably 1.5 or more and 5.0 or less, more preferably 1.8 or more and 3.0 or less.

From the viewpoint of further compressing the low basis weight portion 32 and making it easier for the long convex portion 41 to fold inward, when the length of the long convex portion 41 in the second direction X is L2 (see FIG. 4) and the length of the low basis weight portion 32 in the second direction X is L5 (see FIG. 4), the ratio of L5 to L2, L5/L2, is preferably 0.3 or more, more preferably 0.4 or more, and also preferably 0.8 or less, more preferably 0.7 or less, and also preferably 0.3 or more and 0.8 or less, more preferably 0.4 or more and 0.7 or less.

From the viewpoint of making the low basis weight portion 32 more susceptible to compressive forces in the first direction Y and more likely to cause inward folding in the long convex portion 41, when the length of the long convex portion 41 in the second direction X is L2 (see FIG. 4) and the length of the low basis weight portion 32 in the first direction Y is L6 (see FIG. 4), the ratio of L6 to L2, L6/L2, is preferably 0.3 or more, more preferably 0.4 or more, and also preferably 1.5 or less, more preferably 1.0 or less, and also preferably 0.3 to 1.5, more preferably 0.4 to 1.0.

The long convex portion 41 of this embodiment has only one portion a that overlaps with the large concave portion 31 in the first direction Y , i.e., only one inward bent portion a.
When the length of the long convex portion 41 in the first direction Y is L1 (see FIG. 4) and the length of the inward bent portion a in the first direction Y is L10 (see FIG. 5(b)), the ratio of L10 to L1, L10/L1, is preferably 0.2 or more, more preferably 0.3 or more, and also preferably 0.8 or less, more preferably 0.7 or less, and also preferably 0.2 or more and 0.8 or less, more preferably 0.3 or more and 0.7 or less. The length L10 of the inward bent portion a in the first direction Y is the maximum length of the valley portion v of the inwardly bent long convex portion 41 along the first direction Y (see FIG. 5(b)).
When the long protrusion 41 has a plurality of inward bent portions a along the first direction Y as in the third and fourth embodiments described later, the length L10 of the inward bent portions a in the first direction Y is the sum of the lengths of the plurality of inward bent portions a in the first direction Y. For example, when one long protrusion 41 has two inward bent portions _a1 and _a2 as in the third embodiment, the length L10 of the inward bent portion in the first direction Y is the sum of the lengths of the two inward bent portions _a1 and _a2 in the first direction Y.

From the viewpoint of further improving the feel on the skin in the uneven area P, it is preferable that the dimensions of the long convex portions 41 and the low basis weight portions 32 are within the following ranges.
The length L1 (see FIG. 4) of the long convex portion 41 in the first direction Y is preferably 4.0 mm or more, more preferably 6.0 mm or more, and is preferably 35.0 mm or less, more preferably 25.0 mm or less, and is preferably 4.0 mm or more and 35.0 mm or less, more preferably 6.0 mm or more and 25.0 mm or less.
The length L2 (see FIG. 4) of the long convex portion 41 in the second direction X is preferably 2.0 mm or more, more preferably 3.0 mm or more, and is preferably 7.0 mm or less, more preferably 5.0 mm or less, and is preferably 2.0 mm or more and 7.0 mm or less, and more preferably 3.0 mm or more and 5.0 mm or less.
The height H1 of the long convex portion 41 [see FIG. 5(a)] is preferably 0.5 mm or more, more preferably 0.8 mm or more, and is preferably 4.0 mm or less, more preferably 3.0 mm or less, and is preferably 0.5 mm or more and 4.0 mm or less, more preferably 0.8 mm or more and 3.0 mm or less.

The length L6 (see FIG. 4) of the low basis weight portion 32 in the first direction Y is preferably 0.8 mm or more, more preferably 1.0 mm or more, and is preferably 10.0 mm or less, more preferably 7.0 mm or less, and is preferably 0.8 mm or more and 10.0 mm or less, more preferably 1.0 mm or more and 7.0 mm or less.
The length L5 (see FIG. 4) of the low basis weight portion 32 in the second direction X is preferably 0.8 mm or more, more preferably 1.0 mm or more, and is preferably 6.0 mm or less, more preferably 4.0 mm or less, and is preferably 0.8 mm or more and 6.0 mm or less, more preferably 1.0 mm or more and 4.0 mm or less.

In this embodiment, the central concave-convex region P has a large concave portion 31 and a small concave portion 33 (see FIG. 3). In this embodiment, the small concave portion 33 has an opening (not shown) as a low basis weight portion. The small concave portion 33 may not have a low basis weight portion.
In the long convex portion 41 of the present embodiment, even if the elastic member exhibiting stretchability in the first direction Y contracts, no inward folding occurs in the portion sandwiched between the small recesses 33 in the second direction X. In this way, the central uneven region P may have recesses 33 that do not contribute to the inward folding of the long convex portion 41.
Examples of the recesses 33 that do not contribute to the inward folding of the long convex portion 41 include recesses having a length in the first direction Y of less than 0.5 mm, recesses that do not have a low basis weight portion, and recesses that are formed by compaction such as embossing.

In the diaper 1 of this embodiment, the waist elastic member 19 is stretchable along the lateral direction _Y1 . The waist elastic member 19 and the central uneven region P overlap at an end of the diaper 1 in the longitudinal direction _X1 , specifically, at the waist flap portion WF in the back portion B. In the diaper 1 of this embodiment, the central uneven region P having the long convex portion 41 that can be folded inward is disposed around the waist of the wearer (waist portion) when the diaper 1 is worn. This allows the skin contact sheet 10 to easily fit around the waist, and the uneven region P maintains good breathability, making it less likely for stuffiness to occur.

In the diaper 1 of this embodiment, as shown in FIG. 6, the waist elastic member 19 is arranged in a stretched state between the top sheet 12, which is the skin contact sheet 10, and the back sheet 13 in the waist flap portion WF, and the top sheet 12 and the waist elastic member 19 are overlapped in a state of direct contact. This configuration is preferable in that it makes it easier to apply the contraction force (stretching stress) of the elastic member 19 to the large recesses 31 or the low basis weight portions 32, and makes it easier to cause the long protrusions 41 to fold inward.

The skin contact sheet 10 and the elastic member arranged to exhibit stretchability along the first direction may be overlapped with another member interposed between the skin contact sheet 10 and the elastic member. For example, as shown in Fig. 7 and Fig. 8, the top sheet 12 of the skin contact sheet 10 may be overlapped with the elastic member 19 arranged to exhibit stretchability along the first direction Y with the absorbent body 14 interposed therebetween. In this case, from the viewpoint of imparting the contractile force (elongation stress) of the elastic member 19 to the large recesses 31 or the low basis weight portions 32 more effectively, it is preferable that the absorbent core 14a has a core low basis weight portion 14c having a low basis weight of absorbent material, and that the elastic member 19, the concave-convex region P having the inwardly foldable long convex portions 41, and the core low basis weight portion 14c overlap with each other.
The core low basis weight portion 14c may be a low-fiber stacking portion in which the basis weight of the forming material of the absorbent core 14a is smaller than that of the portions of the absorbent core 14a other than the core low basis weight portion 14c and in which the forming material is present, or it may be a penetrating portion in which no forming material is present and which penetrates the absorbent core 14a.

From the viewpoint of imparting more of the contractile force (elongation stress) of the elastic member 19 to the low basis weight portion 32, when the core low basis weight portion 14c is a low stacking portion, the absorbent core 14a has a basis weight of the absorbent material in the core low basis weight portion 14c that is preferably greater than 0%, more preferably greater than 20%, and preferably less than 80%, more preferably less than 60%, relative to the basis weight of the absorbent material in portions other than the core low basis weight portion 14c.
From the same viewpoint as above, when the core low basis weight portion 14c is a low stacking portion, the basis weight of the absorbent material in the core low basis weight portion 14c is preferably greater than 0 g/ ^m2 , more preferably greater than 40 g/ ^m2 , and is preferably less than 500 g/ ^m2 , more preferably ^less than 400 g/m2, and is preferably greater than 0 g/ ^m2 and less than 500 g/ ^m2 , more preferably greater than 40 g/ ^m2 and less than 400 g/ ^m2 .

7, the first direction Y of the long convex portion 41 and the extending direction of the elastic member 19 coincide with the lateral direction _Y1 of the diaper, while the core low basis weight portion 14c extends in the longitudinal direction _X1 .
8, the first direction Y of the long convex portions 41, the extending direction of the elastic members 19, and the extending direction of the core low basis weight portion 14c are aligned with the longitudinal direction _X1 of the diaper. In this manner, it is preferable that the first direction Y of the long convex portions 41 in the uneven region P is aligned with the extending direction of the core low basis weight portion 14c, since this can further improve the fit of the skin-contact sheet 10.

7 and 8, the contraction of the elastic member 19 stretchable along the transverse direction _Y1 may cause the inward folding of the inwardly foldable convex portions 41 in the uneven region P, or the contraction of the elastic member stretchable along the longitudinal direction _X1 may cause the inward folding of the inwardly foldable convex portions 41 in the uneven region P. That is, the first direction of the long convex portions 41 in the uneven region P may coincide with the transverse direction _Y1 of the diaper 1, or the first direction may coincide with the longitudinal direction _X1 .
8, the elastic member stretchable in the longitudinal direction _X1 and the uneven region P having the long convex portion 41 capable of being folded inward preferably overlap in the central portion of the diaper 1 in the longitudinal direction _X1 , and more preferably overlap in the crotch portion C. This configuration more effectively prevents the skin-contact sheet 10 from coming into close contact with the wearer's skin, and more effectively prevents stuffiness caused by urine and other excrement absorbed in the absorber 14, and liquid backflow, which is the migration of liquid once absorbed in the absorber 14 to the topsheet 12 due to the wearer's body pressure or the like.

In the skin contact sheet 10 of the present embodiment, the side uneven region PS has protrusions 47 and recesses 37 arranged in a staggered pattern. The protrusions 47 in the side uneven region PS may or may not be bent inwardly due to contraction of the elastic member.
When an inward fold occurs in the convex portion 47 in the side concave-convex region PS, the above description of the central concave-convex region P is applied as appropriate.

Figures 9 to 13 show other embodiments of the skin contact sheet according to the present invention. For the skin contact sheets of the second to sixth embodiments described below, components that differ from the embodiment (first embodiment) shown in Figures 1 to 8 will be mainly described, and similar components will be given the same reference numerals and will not be described. For components that are not described in particular, the description of the first embodiment will be applied as appropriate.

5 and 6, the skin contact sheet 10 of the first embodiment described above has a single layer structure, and the inside of the long convex portion 41 is solid. The non-skin facing surface of the skin contact sheet 10 is flat when stretched along the first direction Y. The "stretched state along the first direction Y" refers to the state in which the skin contact sheet 10 having the inwardly foldable convex portion 41 is stretched as follows.
The diaper 1 in an unfolded state is spread in the first direction Y to the design dimensions (the same as the dimensions when spread out flat with all influence of the elastic members completely eliminated), and two marks are made on the skin contact sheet 10 of the diaper 1 with an oil-based pen, spaced a certain distance L0 (e.g., 100 mm) apart in the first direction Y. Next, the skin contact sheet 10 is removed from the diaper 1, and stretched in the first direction Y until the distance between the two marks on the sheet 10 is the length of the certain distance L0. This state is referred to as the "stretched state along the first direction Y."

Instead of a sheet having a single layer structure, the skin contact sheet 10a of the second embodiment may be a composite sheet in which a laminated first sheet 21 and a second sheet 22 are joined to each other at a plurality of joining portions 36, as shown in Fig. 9. In this case, the first sheet 21 forms a long convex portion 41 that protrudes in a direction away from the second sheet 22 at a portion other than the recesses 31, 33.
In the composite sheet 10a stretched in the first direction Y, the surface formed by the second sheet 22, i.e., the non-skin-facing surface, is flat. In the composite sheet 10a, the long convex portion 41 is hollow and has a two-layer structure of the first sheet 21 and the second sheet 22. Therefore, the compressive force of the low basis weight portion 32 tends to concentrate on the first sheet 21, and the long convex portion 41 formed by the first sheet 21 tends to be folded inward.

The skin contact sheets 10b, 10c of the third and fourth embodiments shown in Figs. 10 and 11 have a different pattern of the concave-convex regions P from the skin contact sheet 10 of the first embodiment.
10, in the skin contact sheet 10b of the third embodiment, the long protrusions 41 are arranged in a staggered pattern, and recesses 31a each having four low basis weight portions 32a are formed between the long protrusions 41 in the second direction X. A plurality of longitudinal concave-convex rows R11 are formed in the first direction Y, in which the long protrusions 41 and recesses 31a are alternately arranged along the second direction X.
In the third embodiment, the positions of the long convex portions 41 and the positions of the concave portions 31a of the vertical concave-convex rows R11 adjacent to each other in the first direction Y are shifted in the second direction X by half a pitch.
In addition, two sets of two low basis weight sections 32a (a pair of low basis weight sections 32a, 32a) lined up along the second direction X are arranged between the long convex sections 41 in the first direction Y, and these four low basis weight sections 32a and the long convex sections 41 are arranged alternately along the second direction X.
The vertical concave-convex row R11 is composed of a long convex portion row R4 consisting of a plurality of long convex portions 41 arranged intermittently along the second direction X, and two low basis weight portion rows R3 in which a pair of low basis weight portions 32a, 32a arranged in the second direction X between the long convex portions 41 are arranged intermittently along the same direction X.
In the third embodiment, each long convex portion 41 in the vertical concave-convex row R11 has regions _f1 , _f2 that overlap in the first direction Y with each of the two low basis weight portions 32a aligned in the first direction Y. In other words, the long convex portion 41 has two regions that overlap with the low basis weight portions 32a in the first direction Y. In the long convex portion 41, in the regions _f1 , _f2 that overlap with these low basis weight portions 32a, 32a in the first direction Y, inward folding occurs preferentially due to contraction of the elastic member 19. That is, the long convex portion 41 in the third embodiment has a plurality of inward folding portions _a1 , _a2 along the first direction Y, and inward folding occurs in each of the plurality of inward folding portions _a1 , _a2 due to contraction of the elastic member that exhibits stretchability in the first direction Y.

In the third embodiment, the long convex portion 41 has two inward bends _a1 and _a2 along the first direction Y, but the long convex portion 41 may have three or more inward bends along the first direction Y.
11, the skin contact sheet 10c of the fourth embodiment has long protrusions 41 arranged in a staggered pattern, and recesses 31b each having a rectangular large low basis weight portion 32b and four small low basis weight portions 32c positioned approximately diagonally outside the large low basis weight portion 32b are formed between the long protrusions 41 in the second direction X. A plurality of longitudinal concave-convex rows R13 are formed along the first direction Y, in which the long protrusions 41 and recesses 31b are alternately arranged along the second direction X.
In the fourth embodiment, the positions of the long convex portions 41 and the positions of the concave portions 31b of the vertical concave-convex rows R13 adjacent to each other in the first direction Y are shifted in the second direction X by half a pitch.
In the longitudinal concave-convex row R13, the large low basis weight portions 32b and the long convex portions 41 are arranged alternately in the second direction X.
In addition, two small low basis weight sections 32c arranged on each side of the large low basis weight section 32b in the first direction Y are lined up along the second direction X, and these two low basis weight sections 32c and the long convex sections 41 are lined up alternately along the second direction X.
The longitudinal uneven row R13 is composed of a long convex portion row R8 consisting of a plurality of long convex portions 41 arranged intermittently along the second direction X, two low basis weight portion rows R7 in which a pair of small low basis weight portions 32c, 32c arranged in the second direction X between the long convex portions 41 are arranged intermittently along the same direction X, and a large low basis weight portion row R9 arranged intermittently along the second direction X.
In the fourth embodiment, each long convex portion 41 in the longitudinal concave-convex row R13 has three regions in the first direction Y: a region _f4 overlapping the large low basis weight portion 32b in the first direction Y, and regions _f3 and _f5 overlapping two small low basis weight portions 32c in the first direction Y. In these three regions _f3 , _f4 , and _f5 , inward folding occurs preferentially due to contraction of the elastic member 19, as in the third embodiment. That is, the long convex portion 41 in the fourth embodiment has three inward folding portions _a3 , _a4 , and _a5 along the first direction Y, and inward folding occurs in each of these three inward folding portions _a3 , _a4 , and _a5 due to contraction of the elastic member that exhibits stretchability in the first direction Y.

In the first to fourth embodiments, the concave-convex regions have the long convex portions 41 and the concave portions 31 arranged in a scattered manner, but the long convex portions 41 and the concave portions 31 may each be continuous in one direction.
The skin-contact sheet 10d of the fifth embodiment has a ridge-and-groove shape on its skin-facing surface, as shown in Fig. 12. Specifically, continuous convex portions 41a forming ridges extending in the first direction Y and continuous concave portions 31d forming grooves extending in the same direction as the continuous convex portions 41a are alternately arranged along the second direction X. The skin-facing surface of the skin-contact sheet 10d has a corrugated uneven shape (not shown) when viewed in a direction perpendicular to the extending direction of the continuous convex portions 41a and the continuous concave portions 31d.
The continuous recess 31d in the fifth embodiment has a plurality of low basis weight portions 32 intermittently arranged along the first direction Y, and the arrangement positions of the low basis weight portions 32 in the continuous recesses 31d adjacent to each other in the second direction X are consistent in the first direction Y. That is, a plurality of vertical concave-convex rows R15 are formed along the first direction Y, in which the continuous convex portions 41a and the low basis weight portions 32 of the continuous recesses 31d are alternately arranged along the second direction X.
In the fifth embodiment, in the longitudinal concave-convex row R15 aligned along the second direction X, each continuous convex portion 41a has a plurality of regions _f9 overlapping with the low basis weight portion 32 in the first direction Y. In these plurality of regions _f9 , inward folding occurs preferentially due to contraction of the elastic member 19, as in the third embodiment. That is, the long convex portion 41 in the fifth embodiment has a plurality of inward folding portions _a9 along the first direction Y, and inward folding occurs in each of the plurality of inward folding portions _a9 due to contraction of the elastic member that exhibits stretchability in the first direction Y.

When the uneven region has a continuous convex portion 41a and a continuous concave portion 31d as in the fifth embodiment, the length L1 of the long convex portion in the first direction Y is the total length (30 mm) of the convex portion in the first direction Y, assuming that the continuous convex portion 41a is a convex portion per unit area (30 mm square).
Furthermore, the total length L10 of the inward bends _a9 in the first direction Y is the total length in the first direction Y of the inward bends _a9 present in the convexity per unit area (30 mm square) when the continuous convexity 41a is assumed to be a convexity per unit area (30 mm square). The total length L10 of the inward bends _a9 in the first direction Y is the average length of convexities per unit area at five locations arbitrarily selected from each of the ten arbitrarily selected continuous convexities 41a. In this case, the "convexity per unit area" is set to a range that maximizes the number of inward bends _a9 in the convexity.

As shown in Fig. 13, the skin contact sheet 10e in the sixth embodiment has a plurality of long protrusions 41b and recesses 31d protruding toward the skin-facing surface side, and the long protrusions 41b are open on the non-skin-facing surface side to form spaces. In the skin contact sheet 10e, the back side of the recesses 31d, i.e., the non-skin-facing surface of the recesses 31d, protrudes toward the non-skin-facing surface side, and when the skin contact sheet 10e is viewed from the non-skin-facing surface side, the protruding portion on the back side of the recesses 31d is a protrusion protruding toward the non-skin-facing surface side. The skin-facing surface side of the recesses 31d is open to form spaces. These long protrusions 41b and recesses 31d are alternately and continuously arranged along two different directions that intersect with each other in a plan view over the entire surface of the skin contact sheet 10e.
In the sixth embodiment, the recess 31d has the low fiber-stacking portion described above as the low basis weight portion 32d.

The materials forming each part of the diaper in the above-mentioned embodiment will be described in detail. The back sheet 13 and the absorbent body 14 can be made of materials conventionally used in absorbent articles, without any particular restrictions. The back sheet 13 can be made of a resin film with low liquid permeability, or a laminate of a resin film and a nonwoven fabric, etc. The absorbent body 14 can be made of an absorbent core 14a made of an assembly of hydrophilic fibers such as wood pulp or synthetic fibers treated to be hydrophilic, or a material in which the assembly holds a water-absorbent polymer. The core wrap sheet 14b can be made of the same material as the top sheet 12. The three-dimensional gather forming sheet 15 can be made of a water-repellent nonwoven fabric.

The top sheet 12, which is the skin-contacting sheet 10, can be, for example, a liquid-permeable nonwoven fabric that is conventionally used in absorbent articles. Examples of nonwoven fabrics include air-through nonwoven fabrics, spunbond nonwoven fabrics, spunlace nonwoven fabrics, meltblown nonwoven fabrics, resin-bonded nonwoven fabrics, and needle-punched nonwoven fabrics. A laminate combining two or more of these nonwoven fabrics can also be used.

Fibers made of various thermoplastic resins can be used as the fibers constituting the nonwoven fabric. Examples of thermoplastic resins 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, and polyvinylidene chloride. These resins can be used alone or as a blend of two or more types. They can also be used in the form of composite fibers such as core-sheath type and side-by-side type.

The above-mentioned elastic members 15a, 16, 19 may be, for example, synthetic rubber such as styrene-butadiene, butadiene, isoprene, neoprene, natural rubber, EVA, elastic polyolefin, polyurethane, etc. As for the form of the elastic member, it is preferable to use a thread-like member (e.g., rubber thread), a string-like member (e.g., flat rubber) or a multifilament type thread-like member having a rectangular, square, circular, elliptical or polygonal cross section.

In addition, a stretch sheet 130 may be used as each of the elastic members 15a, 16, and 19 described above. As shown in FIG. 14, the stretch sheet 130 is made up of a plurality of elastic filaments 131 arranged to extend in one direction without intersecting each other, and joined to stretchable nonwoven fabrics 132 and 133 over their entire length in a substantially unstretched state.

Each elastic filament 131 is bonded to the first and second nonwoven fabrics 132, 133. The first nonwoven fabric 132 and the second nonwoven fabric 133 may be of the same type or different types. The same type of nonwoven fabric means nonwoven fabrics that are all the same in terms of the manufacturing process of the nonwoven fabric, the type of fibers that make up the nonwoven fabric, the fiber diameter and length of the fibers that make up the nonwoven fabric, the thickness and basis weight of the nonwoven fabric, etc. If at least one of these is different, the nonwoven fabrics are said to be of different types. In addition, "elasticity" refers to the property of being able to be stretched and returning to a length of 125% or less of the original length when the force is released from a state where it is stretched 100% of its original length (200% of the original length).

Each of the nonwoven fabrics 132, 133 is stretchable. Each of the nonwoven fabrics 132, 133 is stretchable in the same direction as the extension direction of the elastic filament 131. Stretchable includes (a) the case where the constituent fibers of the nonwoven fabrics 132, 133 themselves stretch, and (b) the case where the constituent fibers themselves do not stretch, but the nonwoven fabric as a whole stretches by separating fibers that were bonded at the intersections, structurally changing the three-dimensional structure formed by multiple fibers due to bonding between fibers, etc., tearing of the constituent fibers, or stretching of slack fibers.

Each nonwoven fabric 132, 133 may already be stretchable in the form of a raw roll before being joined to the elastic filament 131. Alternatively, the nonwoven fabric may not be stretchable in the form of a raw roll before being joined to the elastic filament 131, but may be processed to become stretchable after being joined to the elastic filament 131. Specific methods for making the nonwoven fabric stretchable include heat treatment, inter-roll stretching, bite stretching using grooves or gears, and tensile stretching using a tenter.

Each elastic filament 131 is substantially continuous over the entire length of the stretch sheet 130. The elastic filaments 131 contain an elastic resin. The elastic filaments 131 are arranged to extend in one direction without crossing each other. However, due to inevitable variations in the manufacturing conditions of the stretch sheet 130, it is permitted that the elastic filaments 131 may cross unintentionally. As long as the elastic filaments 131 do not cross each other, they may extend in a straight line or in a meandering manner.

The stretch sheet 130 described above has a structure in which the elastic filament 131 is arranged between two stretchable nonwoven fabrics 132, 133, but instead, a stretch sheet having a structure in which the elastic filament 131 is arranged on one surface of a single stretchable nonwoven fabric may be used. In this case, the elastic filament 131 is exposed.

The skin contact sheet of the present invention can be produced by a known production method.
For example, the skin contact sheet 10 of the first embodiment can be manufactured by a manufacturing method including a step of imparting an uneven shape to a sheet to form recesses and protrusions, and a step of forming low basis weight portions in the recesses. In such a manufacturing method, a sheet is introduced between an embossing roll and a flat roll arranged opposite to each other to impart an uneven shape, and then low basis weight portions are formed in the recesses of the uneven shape using ultrasonic treatment or the like.
The composite sheet (skin contact sheet 10a) of the second embodiment can be manufactured by the manufacturing method described in JP 2018-099883 A. This manufacturing method includes a step of imparting an uneven shape to the first sheet 21, a superposing step of superposing the second sheet 22 on the first sheet 21, and an ultrasonic treatment step of applying ultrasonic vibrations to both sheets 21 and 22. The step of imparting an uneven shape introduces the first sheet 21 into the meshing portion of the first and second rolls, which have meshing unevenness on their circumferential surfaces, while rotating the first and second rolls, and deforms the first sheet 21 into an uneven shape. The superposing step conveys the first sheet 21, which has been deformed into an uneven shape, while being held on the first roll, and the second sheet 22 is superposed on the first sheet 21 during conveyance. In the ultrasonic treatment process, the overlapping sheets 21, 22 are sandwiched between the convex portion of the first roll and the ultrasonic horn of the ultrasonic fusion machine and ultrasonic vibrations are applied to form a low basis weight portion 32 consisting of openings penetrating the skin contact sheet 10a.

In addition to ultrasonic treatment, known cutting means capable of partially cutting a sheet that has been deformed into an uneven shape can be used to form the low basis weight portion 32 consisting of perforations. Examples of such cutting means include a cutting device equipped with a cutter roll and anvil roll, in which the outer peripheral surface of the cutter roll has a cutting blade that corresponds to the contour of the perforations.

While the present invention has been described based on the preferred embodiments, the present invention is not limited to the above-described embodiments and can be modified as appropriate.
For example, the skin-contact sheet 10 in the first embodiment had a central uneven region P and side uneven regions PS located on both sides of it, but long convex portions 41 and concave portions 31, 33 in the same pattern as the central uneven region P may be formed over the entire surface of the skin-contact sheet 10.
Furthermore, the uneven region P may have a region that overlaps with the elastic member 19 and a region that does not overlap with the elastic member 19. In this case, the width in the first direction Y of the convex portion in the region that overlaps with the elastic member 19 and the convex portion in the region that does not overlap with the elastic member 19 may be the same as or different from each other. For example, the width in the first direction of the convex portion in the region that overlaps with the elastic member 19 may be smaller than the width in the first direction of the convex portion in the region that does not overlap with the elastic member 19.

The shape of the low basis weight portion 32 may be any shape that is elongated in the first direction Y. For example, the shape of the low basis weight portion 32 may be a rectangle, an ellipse, an oval, a triangle, a pentagon, a hexagon, a star, a heart, or the like.
In addition, the absorbent article of the present invention may be a pants-type (pull-on type) disposable diaper instead of an unfolded type disposable diaper, or may be a pants-type or normal non-pants-type sanitary napkin, an incontinence pad, a panty liner, etc.

In relation to the above-mentioned embodiments, the present invention further discloses the following absorbent article.
＜1＞
An absorbent article comprising a skin contact sheet having a concave-convex region, the concave-convex region contacting the skin of a wearer when the absorbent article is worn, the skin contact sheet having a longitudinal direction corresponding to the front-to-rear direction of the wearer and a lateral direction perpendicular to the longitudinal direction,
the concave-convex region has a first direction and a second direction perpendicular to the first direction, and includes a plurality of convex portions whose length in the first direction is longer than that in the second direction, and a plurality of concave portions located between the convex portions in the first direction or the second direction,
The absorbent article further comprises an elastic member disposed along a first direction on the non-skin facing side of the skin contact sheet.

＜2＞
The absorbent article according to the above-mentioned item <1>, wherein the protrusions are deformed such that the portions sandwiched between the recesses in the second direction are folded toward the inside of the protrusions due to contraction of the elastic member. <3>
The absorbent article according to <1> or <2>, wherein the elastic member is arranged so as to exhibit stretchability along a first direction.
＜4＞
The absorbent article according to any one of <1> to <3>, wherein the tensile stress of the elastic member is 8 cN/10 mm or more and 50 cN/10 mm or less, preferably 10 cN/10 mm or more and 40 cN/10 mm or less.
＜5＞
The absorbent article according to any one of <1> to <4>, wherein the recesses have low basis weight portions having a fiber material with a smaller basis weight than the protrusions.
＜6＞
the protrusion has an inner folding portion that is deformed such that a portion sandwiched between the recesses in the second direction is folded toward the inside of the protrusion due to contraction of the elastic member,
The absorbent article according to <5> above, wherein the inwardly folded portion is located closer to the skin-facing surface than the low basis weight portion.
＜７＞
The absorbent article according to <5> or <6>, wherein the elastic member is located on a non-skin-facing side of the low basis weight portion.
＜8＞
The absorbent article according to any one of <5> to <7>, wherein the basis weight of the fiber material in the low basis weight portion is 10% or less, preferably 20% or less, of the basis weight of the fiber material in the protrusions having a length in the first direction longer than the length in the second direction.
＜9＞
The absorbent article according to any one of <5> to <8>, wherein the basis weight of the fiber material in the low basis weight portion is 30 g/m2 ^or less, preferably 20 g/m2 ^or less.
＜10＞
The absorbent article according to any one of <5> to <7>, wherein the low basis weight portion is formed of an aperture penetrating the skin contact sheet.

<11>
The absorbent article according to any one of <5> to <10>, wherein the uneven region has a plurality of low basis weight portion rows intermittently formed in the first direction, the low basis weight portions being arranged in a second direction.
＜12＞
The absorbent article according to <11>, wherein a plurality of rows of the low basis weight portions are formed at equal intervals in the first direction.
＜13＞
The absorbent article according to any one of <5> to <12>, wherein, when a length of the convex portion in the second direction is L2 and a length of the low basis weight portion in the second direction is L5, a ratio of L5 to L2, L5/L2, is 0.3 or more, preferably 0.3 or more and 0.8 or less, and more preferably 0.4 or more and 0.7 or less.
＜14＞
The absorbent article according to any one of <5> to <13>, wherein, when the length of the convex portion in the second direction is L2 and the length of the low basis weight portion in the first direction is L6, the ratio of L6 to L2, L6/L2, is 0.3 or more, preferably 0.3 or more and 1.5 or less, and more preferably 0.4 or more and 1.0 or less.
＜15＞
The convex portion has one or more portions along the first direction that are sandwiched between the low basis weight portions in the second direction,
The absorbent article according to any one of <1> to <14>, wherein, when the length of the convex portion in the first direction is L1 and the sum of the lengths of the sandwiched portions in the first direction is L10, the ratio of L10 to L1, L10/L1, is 0.2 or more, preferably 0.2 or more and 0.8 or less, and more preferably 0.3 or more and 0.7 or less.
＜16＞
The absorbent article according to any one of <1> to <15>, wherein the convex portion has a portion in which constituent fibers of the skin contact sheet are oriented along a second direction.
＜１７＞
The absorbent article according to any one of <1> to <16>, wherein the convex portion has a portion in which constituent fibers of the skin contact sheet are oriented along a first direction.
＜18＞
The absorbent article according to any one of <1> to <17>, wherein the protrusions satisfy the following formula (1) when the elastic member is maximally stretched:
La>H1...(1)
La: half the length L1 of the convex portion in the first direction H1: the height of the convex portion <19>
The absorbent article according to <18> above, wherein La/H1, which is a ratio of La to H1, is 1.5 or more and 15.0 or less, preferably 2.0 or more and 10.0 or less.
＜20＞
the skin contact sheet is a composite sheet in which a first sheet and a second sheet are laminated and joined to each other at a plurality of joining portions,
the first sheet forms the convex portion protruding in a direction away from the second sheet at a portion other than the concave portion,
The absorbent article according to any one of <1> to <19>, wherein in a stretched state along the first direction, the composite sheet has a flat surface formed by the second sheet.

＜21＞
The absorbent article according to any one of <1> to <20>, wherein, when a length of the convex portion in the second direction is L2 and a length of the convex portion in the first direction is L1, a ratio of L1 to L2, L1/L2, is 1.5 or more and 5.0 or less, preferably 1.8 or more and 3.0 or less.
＜22＞
The elastic member is stretchable along the lateral direction,
The absorbent article according to any one of <1> to <21>, wherein the elastic member and the uneven area overlap at an end of the absorbent article in the longitudinal direction.
＜23＞
The elastic member is stretchable along the longitudinal direction,
The absorbent article according to any one of <1> to <22>, wherein the elastic member and the uneven area overlap at a center part of the absorbent article in the longitudinal direction.
＜24＞
an absorbent core including an absorbent material;
The absorbent core has a low basis weight portion of the absorbent material extending in the longitudinal direction,
The absorbent article according to <23>, wherein the elastic member, the uneven area, and the core low basis weight portion overlap with each other.
＜25＞
The absorbent article according to <24>, wherein the basis weight of the core low basis weight portion is more than 0% and not more than 80%, more preferably 20% or more and not more than 60%, of the basis weight of the absorbent material in the portion other than the core low basis weight portion.
＜26＞
The absorbent article according to the above-mentioned <24> or <25>, wherein the basis weight of the core low basis weight portion is more than 0 g/ ^m2 and not more than 500 g/ ^m2 , more preferably 40 g/ ^{m2 or more} and not more than 400 g/m2. <27>
The absorbent article according to any one of <1> to <26>, wherein the elastic member is made of a stretch sheet in which a plurality of elastic filaments are bonded to a stretchable nonwoven fabric.
＜28＞
the concave-convex region has a region that overlaps with the elastic member and a region that does not overlap with the elastic member,
The absorbent article according to any one of <1> to <27>, wherein the width in the first direction of the protrusions in the region overlapping with the elastic member is smaller than the width in the first direction of the protrusions in the region not overlapping with the elastic member.

1. Disposable diapers (absorbent articles)
12 top sheet 13 back sheet 14 absorbent body 19 waist elastic member 10 skin contact sheet 21 first sheet 22 second sheet 31 large recess 32 low basis weight portion 41 long protrusion a inwardly folded portion P central recessed and projected region M central region S side region X second direction Y first direction _X1 longitudinal direction _Y1 lateral direction

Claims (11)

An absorbent article comprising a skin contact sheet having a concave-convex region, the concave-convex region contacting the skin of a wearer when the absorbent article is worn, the skin contact sheet having a longitudinal direction corresponding to the front-to-rear direction of the wearer and a lateral direction perpendicular to the longitudinal direction,
the concave-convex region has a first direction and a second direction perpendicular to the first direction, and includes a plurality of convex portions whose length in the first direction is longer than that in the second direction, and a plurality of concave portions located between the convex portions in the first direction or the second direction,
The recessed portion has a low basis weight portion having a fiber material with a smaller basis weight than the protruding portion,
An elastic member is disposed along a first direction on a non-skin facing side of the skin contact sheet,
In the uneven region, a plurality of low basis weight portion rows are intermittently formed in a first direction, the low basis weight portions being arranged in a second direction, and
An absorbent article , wherein a portion of the convex portion that overlaps with the concave portion in the first direction forms an inward folded portion that deforms so as to fold toward the inside of the convex portion due to contraction of the elastic member . The absorbent article according to claim 1 , wherein the inwardly folded portion is located closer to the skin-facing surface than the low basis weight portion. The absorbent article according to claim 1 or 2 , wherein a plurality of rows of the low basis weight portions are formed at equal intervals in the first direction. The absorbent article according to any one of claims 1 to 3 , wherein the low basis weight portion comprises an aperture penetrating the skin contact sheet. The absorbent article according to any one of claims 1 to 4 , wherein the convex portion has a portion in which constituent fibers of the skin contact sheet are oriented along a second direction. The absorbent article according to any one of claims 1 to 5 , wherein the convex portion has a portion in which constituent fibers of the skin contact sheet are oriented along a first direction. The absorbent article according to any one of claims 1 to 6 , wherein the protrusions satisfy the following formula (1) when the elastic member is maximally stretched:
La>H1...(1)
La: half the length L1 of the protrusion in the first direction H1: height of the protrusion the skin contact sheet is a composite sheet in which a first sheet and a second sheet are laminated and joined to each other at a plurality of joining portions,
the first sheet forms the convex portion protruding in a direction away from the second sheet at a portion other than the concave portion,
The absorbent article according to any one of claims 1 to 7 , wherein in a stretched state along the first direction, the composite sheet has a surface formed by the second sheet that is flat. The elastic member is stretchable along the lateral direction,
The absorbent article according to any one of claims 1 to 8 , wherein the elastic members and the uneven areas overlap at ends of the absorbent article in the longitudinal direction. The elastic member is stretchable along the longitudinal direction,
The absorbent article according to any one of claims 1 to 9 , wherein the elastic member and the uneven area overlap at a central portion of the absorbent article in the longitudinal direction. an absorbent core including an absorbent material;
The absorbent core has a low basis weight portion of the absorbent material extending in the longitudinal direction,
The absorbent article of claim 10 , wherein the elastic member, the relief region, and the low basis weight core portion overlap.

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