JP7763159B2 - Disposable diapers - Google Patents

Description

The present invention relates to a disposable diaper having an absorbent sheet.

Disposable diapers with an absorbent core and a separate absorbent sheet are known. The absorbent sheet is positioned on the skin-facing side in the waist region, which comes into contact with the wearer's skin. Therefore, when worn, the absorbent sheet comes into contact with the skin and absorbs sweat.

JP 2009-148531 A

Absorbent sheets absorb sweat by coming into contact with the skin. Therefore, if the absorbent sheet is separated from the skin, its ability to absorb bodily fluids will decrease, and the absorbent sheet may not be able to fully function.

Therefore, there is a demand for disposable diapers that allow the absorbent sheet to adhere closely to the wearer's skin, improving absorbency.

A disposable diaper according to one embodiment has a longitudinal direction and a width direction that are perpendicular to each other, a front waist region, a rear waist region, and a crotch region disposed between the front waist region and the rear waist region, an absorbent body disposed at least in the crotch region, an absorbent sheet disposed in a first waist region that is one of the front waist region and the rear waist region, a liquid-impermeable backsheet disposed on the non-skin-facing side of the absorbent sheet, and a side joining portion joining the outer edge of the front waist region to the outer side of the rear waist region, The first waist region has a first region that extends in the width direction from one outer edge of the first waist region to the other outer edge and that extends in the longitudinal direction from the inner edge of the water absorbent sheet to the outer edge of the water absorbent sheet. The second waist region, which is the other of the front waist region and the rear waist region, is contiguous with the first region in the width direction and has a second region that extends in the width direction from one outer edge of the second waist region to the other outer edge, and the contractile force in the width direction of the first region is lower than the contractile force in the width direction of the second region.

A disposable diaper according to another embodiment has a longitudinal direction and a width direction that are perpendicular to each other, a front waist region, a rear waist region, and a crotch region disposed between the front waist region and the rear waist region, an absorbent body disposed in at least the crotch region, an absorbent sheet disposed in a first waist region that is one of the front waist region and the rear waist region, a liquid-impermeable back sheet disposed on the non-skin-facing side of the absorbent sheet, and side joining portions joining the outer sides of the front waist region and the rear waist region. When the disposable diaper, in which the second waist region, which is the other of the front waist region and the rear waist region, and the first waist region are continuous in the width direction, is worn on a tubular body so that the diaper is 77% of its stretched state, the ratio of the length between the side joint portions of the first waist region in the worn state to the length between the side joint portions of the second waist region in the worn state is higher than the ratio of the length between the side joint portions of the first waist region to the length between the side joint portions of the second waist region in the stretched state.

1 is a front view of a disposable diaper according to an embodiment. 2 is a plan view of the disposable diaper shown in FIG. 1 as viewed from the skin-facing side. FIG. 2 is a plan view of the disposable diaper shown in FIG. 1 as viewed from the non-skin-facing side. FIG. 3 is a cross-sectional view taken along line AA shown in FIG. 2. 3 is a cross-sectional view taken along line BB shown in FIG. 2. FIG. 2 is a cross-sectional view taken along line CC shown in FIG. FIG. 2 is a cross-sectional view taken along line DD shown in FIG. FIG. 2 is a cross-sectional view taken along line EE shown in FIG. 2 is a diagram showing a state in which the disposable diaper shown in FIG. 1 is attached to a cylindrical body. FIG.

(1) Overview of the Embodiments At least the following matters will become clear from the description of this specification and the accompanying drawings.
A disposable diaper according to one embodiment has a longitudinal direction and a width direction which are perpendicular to each other, a front waist region, a rear waist region, and a crotch region disposed between the front waist region and the rear waist region, an absorbent body disposed at least in the crotch region, an absorbent sheet disposed in a first waist region which is one of the front waist region and the rear waist region, a liquid-impermeable backsheet disposed on the non-skin-facing side of the absorbent sheet, and side joining portions joining outer sides of the front waist region and the rear waist region, The first waist region has a first region that extends in the width direction from one outer edge of the first waist region to the other outer edge and that extends in the longitudinal direction from the inner edge of the absorbent sheet to the outer edge of the absorbent sheet, and the second waist region, which is the other of the front waist region and the rear waist region, is continuous with the first region in the width direction and has a second region that extends in the width direction from one outer edge of the second waist region to the other outer edge, and the contractile force in the width direction of the first region is lower than the contractile force in the width direction of the second region.

According to this aspect, when the first and second regions contract, the first region is pulled toward the second region. This reduces wrinkles in the first region, making it easier for the first region to adhere to the skin. This allows the absorbent sheet to adhere to the skin, improving its ability to absorb body fluids such as sweat.

According to another aspect, a disposable diaper has longitudinal and width directions that are perpendicular to each other, a front waist region, a rear waist region, and a crotch region disposed between the front waist region and the rear waist region, an absorbent body disposed in at least the crotch region, an absorbent sheet disposed in a first waist region that is one of the front waist region and the rear waist region, a liquid-impermeable back sheet disposed on the non-skin-facing side of the absorbent sheet, and side joining portions joining outer portions of the front waist region and the rear waist region, When the disposable diaper, in which the second waist region, which is the other of the front waist region and the rear waist region, and the first waist region are continuous in the width direction, is worn on a tubular body so that the diaper is 77% of its stretched state, the ratio of the length between the side joints of the first waist region to the length between the side joints of the second waist region in the worn state is higher than the ratio of the length between the side joints of the first waist region to the length between the side joints of the second waist region in the stretched state.

According to this aspect, when the garment is worn in a contracted state compared to the stretched state, the ratio of the length between the side seams of the first waist region to the length between the side seams of the second waist region is higher. Therefore, the first waist region moves toward the second waist region when contracting from the stretched state to the worn state. This results in fewer wrinkles than the second waist region, making it easier to fit closely to the skin. This allows the absorbent sheet to fit closely to the skin, improving its ability to absorb bodily fluids such as sweat.

According to one preferred embodiment, the first waist region is the rear waist region.

The wearer is more likely to sweat on the back than on the ventral side. By placing a moisture-absorbing sheet in the rear waist area, which is worn on the back of the wearer, sweat absorption can be further improved.

According to one preferred embodiment, the disposable diaper includes a tape member for disposal, and the tape member is positioned so as to overlap at least a portion of the absorbent sheet when viewed in a plan view in the thickness direction.

The area of the absorbent sheet that overlaps with the tape member is made more rigid by the tape member. This makes the absorbent sheet less likely to wrinkle, and makes it easier to fit the absorbent sheet to the skin.

According to one preferred embodiment, the inner edge of the tape member is positioned inward in the longitudinal direction from the center of the water-absorbent sheet in the longitudinal direction.

In this embodiment, the tape member is positioned inward from the longitudinal center of the absorbent sheet, making it easier to position it in a position that corresponds to the wearer's intergluteal cleft. Therefore, the absorbent sheet overlapping the tape member fits snugly into the cavity of the intergluteal cleft, improving absorbency.

According to one preferred embodiment, the inner edge of the tape member is positioned more inward than the inner edge of the absorbent sheet in the longitudinal direction.

The tape element is positioned inside the inner longitudinal edge of the absorbent sheet, making it easy to position it in a position that corresponds to the wearer's gluteal cleft. Therefore, the absorbent sheet overlapping the tape element fits snugly into the cavity of the gluteal cleft, improving absorbency.

According to one preferred embodiment, the tape member overlaps the center of the rear waistband region in the width direction when viewed in a plan view in the thickness direction.

The tape element overlaps the center of the rear waistband region in the width direction, allowing it to easily fit into the wearer's gluteal cleft when worn. This allows the absorbent sheet that overlaps the tape element to adhere closely, further improving absorbency.

In one preferred embodiment, the absorbent sheet has an outer region extending outward in the longitudinal direction from the outer edge of the absorbent sheet in the longitudinal direction, and an inner region extending inward in the longitudinal direction from the inner edge of the absorbent sheet in the longitudinal direction, and the widthwise contraction force of the region in which the absorbent sheet is disposed is higher than the widthwise contraction force of at least one of the outer region and the inner region.

Because the contractile force of the area where the absorbent sheet is placed is greater than that of either the outer or inner area, the area where the absorbent sheet is placed fits easily to the body without floating above the wearer's skin. By fitting the absorbent sheet to the body, it can efficiently absorb bodily fluids, improving absorbency.

According to one preferred embodiment, the widthwise contraction force of the region in which the water-absorbent sheet is disposed is higher than the widthwise contraction force of the outer region and the widthwise contraction force of the inner region.

According to this aspect, the area where the absorbent sheet is placed fits the body better than the outer and inner areas. This makes it less likely for the absorbent sheet to lift up from the periphery of the skin, ensuring good adhesion of the absorbent sheet.

According to one preferred embodiment, the widthwise contraction force of the first waist region is lower than the widthwise contraction force of the second waist region.

When the first and second waist regions contract, the first waist region is pulled toward the second waist region. This reduces wrinkles in the first waist region, making it easier for the first waist region to adhere to the skin. This allows the absorbent sheet to adhere to the skin, improving absorbency.

According to one preferred embodiment, the length between the outer edge of the first waist region and the outer edge of the front absorbent body in the longitudinal direction is longer than the length between the outer edge of the second waist region and the outer edge of the front absorbent body.

According to this aspect, the first waist region is less susceptible to the effects of the absorbent main body being compressed by the wearer's legs, making it easier to maintain a tight fit of the absorbent sheet placed in the first waist region.

(2) Embodiments of Disposable Diaper Hereinafter, a disposable diaper according to an embodiment will be described with reference to the drawings. In the following description of the drawings, identical or similar parts are designated by identical or similar reference numerals. However, it should be noted that the drawings are schematic, and the dimensional ratios and the like may differ from those of the actual product. Therefore, specific dimensions and the like should be determined with reference to the following description. Furthermore, the drawings may include parts whose dimensional relationships and ratios differ from one another.

1 is a front view of a disposable diaper 10 according to this embodiment. FIG. 2 is a plan view of the disposable diaper 10 as viewed from the skin-facing side, and FIG. 3 is a plan view of the disposable diaper as viewed from the non-skin-facing side. FIG. 4 is a cross-sectional view taken along line A-A in FIG. 2, and FIG. 5 is a cross-sectional view taken along line B-B in FIG. 2. The plan views shown in FIGS. 2 and 3 show the disposable diaper in a stretched state. Note that the stretched state in this invention refers to a state in which the disposable diaper 10 is stretched to a state in which no wrinkles are formed with the side seam 60 (described below) unfolded. In addition, the natural state in this invention refers to a state in which, in the case of a disposable diaper housed in a package, the disposable diaper is removed from the package and left for 24 hours in an atmosphere of 20°C ± 2°C and a relative humidity of 60% ± 5% RH.

The disposable diaper 10 has a longitudinal direction L and a width direction W that are perpendicular to each other. The longitudinal direction L is defined by the direction extending from the front side to the back side of the body. In other words, the longitudinal direction L is the direction extending from front to back when the disposable diaper 10 is unfolded. The disposable diaper 10 also has a thickness direction T that is perpendicular to both the longitudinal direction L and the width direction W. The thickness direction T extends from the skin-facing side T1 that faces the wearer to the non-skin-facing side T2 that faces away from the wearer.

The disposable diaper 10 has a front waist region S1, a rear waist region S2, and a crotch region S3. The front waist region S1 faces the wearer's front waist (abdomen). The rear waist region S2 faces the wearer's rear waist (back). The crotch region S3 is located between the front waist region S1 and the rear waist region S2, between the wearer's crotch and the rear waist region S2. In this embodiment, the absorbent sheet 70 (described later) is located in the rear waist region S2. Therefore, the rear waist region S2 constitutes the first waist region, and the front waist region S1 constitutes the second waist region. In a modified example, the absorbent sheet 70 may be located in the front waist region S1, the rear waist region S2 constitutes the second waist region, and the front waist region S1 constitutes the first waist region.

The disposable diaper 10 may have a front waistline member 20, a rear waistline member 30, and an absorbent body 40. The front waistline member 20 is arranged in the front waistline region S1, and the region where the front waistline member 20 is arranged is the front waistline region. The rear waistline member 30 is arranged in the rear waistline region S2, and the region where the rear waistline member 30 is arranged is the rear waistline region. The front waistline member 20 constitutes the second waistline member in the present invention, and the rear waistline member 30 constitutes the first waistline member in the present invention. The front waistline member 20 and the rear waistline member 30 may be composed of, for example, nonwoven fabric sheets. Specifically, the front waistline member 20 and the rear waistline member 30 may have a first outer nonwoven fabric sheet 35 arranged on the side closest to the skin-facing surface T2 of the disposable diaper, and a second outer nonwoven fabric sheet 36 arranged on the skin-facing surface side T1 of the first outer nonwoven fabric sheet 35. The first outer nonwoven fabric sheet 35 and the second outer nonwoven fabric sheet 36 constitute the nonwoven fabric sheets of the present invention. The first outer nonwoven fabric sheet 35 and the second outer nonwoven fabric sheet 36 contain thermoplastic fibers. In this embodiment, the basis weight of the first outer nonwoven fabric sheet 35 and the basis weight of the second outer nonwoven fabric sheet 36 may each be 10 g/m ² to 35 g/m ^2. The first outer nonwoven fabric sheet 35 and the second outer nonwoven fabric sheet 36 may be made of spunbonded nonwoven fabric, SMS nonwoven fabric, or point-bonded nonwoven fabric. The first outer nonwoven fabric sheet 35 extends outward in the longitudinal direction L from the inner edge of the front waistline member 20 and the inner edge of the rear waistline member 30 and is folded back toward the skin-facing side T1 from the waistline opening 62 as a base point. The folded-back portion 35F of the first outer nonwoven fabric sheet 35 may be located on the skin-facing side T1 of the disposable diaper near the waistline opening 62 (described later). The folded-back portion 35F of the first exterior nonwoven fabric sheet 35 covers the outer edge of the water-absorbent sheet described below. A first back sheet 51 described below may be disposed between the first exterior nonwoven fabric sheet 35 and the second exterior nonwoven fabric sheet 36. Here, the outer edge in the present invention refers to the edge located on the outer side in the longitudinal direction L, and the inner edge refers to the edge located on the inner side in the longitudinal direction.

The disposable diaper 10 may be provided with a side joint 60 joining the outer side of the front waistline member 20 and the outer side of the rear waistline member 30. The side joint 60 is defined by the portion where the outer side of the front waistline member 20 and the outer side of the rear waistline member 30 are engaged with each other. Here, the "outer side" in this specification refers to a portion occupying a certain range in the width direction, including the edge in the width direction W, and the "outer edge" refers to the edge in the width direction. The side joint 60 may be located widthwise inward of the outer edge 20E of the front waistline member 20 (the outer edge of the front waistline region S1) and the outer edge 30E of the rear waistline member 30 (the outer edge of the rear waistline region S2). Specifically, the outer edge of the side joint 60 may be located 5 mm or more inward of the outer edge 20E of the front waistline member 20 and the outer edge 30E of the rear waistline member 30. As shown in FIG. 1, with the side seam 60 formed, the disposable diaper 10 has a waist opening 62 through which the wearer's waist passes and a pair of leg openings 66 through which the wearer's legs are inserted. The waist opening 62 may be defined by the front edge of the front waist region S1 and the rear edge of the rear waist region S2.

Here, Figure 2 shows the disposable diaper 10 in an unfolded state after the side joints 60 have been released. The side joints 60 may extend along the longitudinal direction L in each of the front waistline member 20 and the rear waistline member 30. In this case, the boundary between the front waistline region S1 and the crotch region S3 may be defined by the rear end edge of the side joints 60 provided on the front waistline member 20. Similarly, the boundary between the rear waistline region S2 and the crotch region S3 may be defined by the front end edge of the side joints 60 provided on the rear waistline member 30.

Stretchable members 32 that are stretchable in the width direction W may be disposed in the front waistline region S1 and the rear waistline region S2. The stretchable members 32 may be made of, for example, rubber thread that is stretchable in the width direction W, or an elastic sheet that is stretchable in the width direction W. Alternatively, the stretchable members 32 may be made of, for example, the front waistline member 20 itself and the rear waistline member 30 itself, which are made of a stretchable sheet.

The contractile force in the width direction W of the front waistband region S1, which constitutes the second waistband region, may be higher than the contractile force in the width direction W of the rear waistband region S2, which constitutes the first waistband region. Because the contractile force of the front waistband region S1 is higher than that of the rear waistband region S2, the outer edge of the rear waistband region S2 in the width direction W is pulled toward the front waistband region S1 when worn. This makes the outer edge of the rear waistband region in the width direction more visible to the wearer when viewed from the front. Furthermore, when the front waistband region S1 and the rear waistband region S2 contract, the rear waistband region S2 is pulled toward the front waistband region S1. Fewer wrinkles are formed in the rear waistband region S2 than in the front waistband region S1, making it easier for the rear waistband region S2 to fit snugly against the skin.

In this embodiment, the contractile force refers to the ease of shrinkage in the width direction, and can be measured as follows. First, the side seams of the disposable diaper are torn to lay the disposable diaper out in an unfolded state. The diaper is cut along the rear edge of the front waistband member and the front edge of the rear waistband member, and the crotch region is separated. This allows samples of the front waistband region and the rear waistband region to be obtained. Furthermore, when measuring the contractile force of the first and second regions described below, the first and second regions can be cut out from the front and rear waistband regions to obtain samples of the first and second regions.

For each sample, 10 mm of each widthwise end is designated as the gripping portion, and the remaining portion is designated as the remaining portion. The widthwise dimension LA (mm) of the remaining portion when unfolded without wrinkles in the longitudinal and widthwise directions (dimensions at 100% stretch) is determined in advance. Then, each gripping portion of the sample is held by the upper and lower chucks of a tensile tester (such as the Shimadzu Autograph AGS-X) and the space between the upper and lower chucks is widened to stretch the contracted sample in the width direction to 85% of the LA at a pulling rate of 100 mm/min. The space between the chucks is then narrowed to 70% of LA. The force exerted when the sample is in this narrowed state is designated the contraction force (N).

The disposable diaper 10 may have a tape member 80 for disposal of the disposable diaper. The tape member 80 may be arranged on the side T2 of the disposable diaper 10 closest to the skin. The tape member 80 may be configured to be extendable in the longitudinal direction L when disposed of, compared to its state before disposal. Specifically, the tape member 80 may be folded around a fold along the width direction W. The bending rigidity of the tape member 80 in the longitudinal direction L may be higher than the bending rigidity in the longitudinal direction of other components constituting the disposable diaper, and the bending rigidity of the tape member 80 in the width direction may be higher than the bending rigidity in the width direction of other components constituting the disposable diaper.

The absorbent main body 40 may be positioned in at least the crotch region S3. The absorbent main body 40 may extend into the front waistline region S1 and the rear waistline region S2. The absorbent main body 40 may be constructed as a separate body from the front waistline member 20 and the rear waistline member 30. In this case, the absorbent main body 40 may be joined to the front waistline member 20 and the rear waistline member 30 in the front waistline region S1 and the rear waistline region S2, respectively. As shown in FIG. 2 , in the longitudinal direction L, the length L12 between the outer edge of the rear waistline region and the outer edge of the absorbent main body may be longer than the length L11 between the outer edge of the front waistline region S1 and the outer edge of the absorbent main body.

The absorbent body 40 includes at least an absorbent core 45. The absorbent core 45 may contain, for example, fluff pulp or superabsorbent polymer (SAP), or a mixture thereof. The absorbent core 45 is located at least in the crotch region S3. Preferably, the absorbent core 45 may extend from the front waist region S1 to the rear waist region S2 in the longitudinal direction L. The absorbent core 45 may be covered by a core wrap. Furthermore, the absorbent body 40 may have a top sheet 41 located on the skin-facing side of the absorbent core 45.

The absorbent body 40 may have leg flaps 46. The leg flaps 46 may be positioned outboard of the absorbent core 45 in the width direction W. The leg flaps 46 may have at least two leg sheets 47 and leg elastic members 48 positioned between the leg sheets 47. The leg sheets 47 may be part of the top sheet 41, part of the back sheet (not shown), or a sheet separate from the top sheet 41 and the back sheet. The leg elastic members 48 are fixed to the leg sheets 47 in a longitudinally stretched state. The leg elastic members 48 may be composed of multiple rubber threads (320 to 620 dtex) spaced apart in the width direction. The leg elastic members 48 are positioned in a stretched state in a predetermined longitudinal region of the leg flaps 46. In the region where the leg elastic members 48 are stretched, a longitudinal contraction force acts on the leg flaps 46, while in the region where the leg elastic members 48 are not stretched, no longitudinal contraction force acts on the leg flaps 46. In this specification, the longitudinal length of the region where this longitudinal contraction force acts is also referred to as the "effective length" of the leg elastic members 48. The effective length portion is the portion where wrinkles are formed due to contraction of the leg elastic members when the diaper is in its natural state. Figure 2 shows the effective length portion 49 of the leg elastic members 48. The absorbent main body 40 is joined to the front waistline member 20 and the rear waistline member 30 at the joining region R40 shown in Figure 2. The effective length portion 49 may overlap the joining region R40.

An absorbent sheet 70 is arranged in one of the front waist region S1 and the rear waist region S2. The absorbent sheet 70 is a sheet capable of absorbing bodily fluids such as sweat. The absorbent sheet 70 may be arranged in the rear waist region S2. A wearer is more likely to sweat on the back side than on the ventral side. By arranging the absorbent sheet 70 in the rear waist region S2, which is worn on the back side of the wearer, sweat absorption can be further improved. The absorbent sheet 70 may have a pulp sheet 71 containing at least pulp fibers. Examples of pulp fibers include wood pulp and non-wood pulp. Examples of wood pulp include softwood pulp and hardwood pulp, and examples of non-wood pulp include cotton pulp, hemp pulp, straw pulp, bamboo pulp, bagasse pulp, reed pulp, and kenaf pulp. The pulp sheet 71 may contain hydrophilic fibers other than pulp fibers. Hydrophilic fibers include natural fibers such as regenerated cellulose fibers (rayon, viscose rayon, etc.), semi-synthetic cellulose fibers (acetate fibers, etc.), and refined cellulose fibers.

The water-absorbent sheet 70 may further include a water-absorbent nonwoven fabric sheet 72. The water-absorbent nonwoven fabric sheet 72 constitutes the nonwoven fabric sheet of the present invention. The water-absorbent nonwoven fabric sheet 72 may be arranged sandwiching the pulp sheet 71 in the thickness direction T. The water-absorbent sheet 70 of this embodiment may include a pulp sheet 71 having a weight of 10 to 35 g/ ^m² and water-absorbent nonwoven fabric sheets 72 having a weight of 10 to 25 g/ ^m² arranged on both sides of the pulp sheet 71 in the thickness direction. The pulp sheet 71 may contain pulp fibers but may not contain thermoplastic fibers. The water-absorbent nonwoven fabric sheet 72 contains thermoplastic fibers. Examples of thermoplastic resin fibers include polyolefin polymers (polyethylene, polypropylene, polyester, polyethylene terephthalate, etc.), polyamide polymers, acrylic polymers, fibers using these, and fibers composed of combinations of these. The water-absorbent sheet 70 may be colored. The coloring may be the color of the pulp sheet itself that constitutes the water-absorbent sheet 70, or may be colored by printing or the like, or a colored portion may be provided in a part of the water-absorbent sheet 70. The colored portion may show a design or picture, or may show a pattern such as stripes. In the absorbent sheet of this embodiment, the entire water-absorbent sheet 70 is colored.

The absorbent sheet 70 is positioned on the closest skin-facing side T1 of the disposable diaper 10. Therefore, the absorbent sheet 70 comes into contact with the wearer's skin when worn. The absorbent sheet 70 comes into contact with the skin and absorbs bodily fluids such as sweat. The absorbent sheet 70 may overlap at least the first outer nonwoven fabric sheet 35 and the second outer nonwoven fabric sheet 36 in the thickness direction. The absorbent sheet 70 is joined to a sheet or other member located on the non-skin-facing side T2 of the absorbent sheet 70 by an adhesive or other bonding means.

The absorbent sheet 70 does not need to overlap the effective length portions of the leg flaps 46 in a plan view in the thickness direction. In a pants-type diaper with a structure in which the front waistband member and the rear waistband member are spaced apart in the longitudinal direction, as in this embodiment, the leg flaps 46 extend outward in the width direction W beyond the absorbent core 45 and are fixed to the front waistband member 20 and the rear waistband member 30, allowing the leg regions of the disposable diaper to fit around the wearer's legs. However, when the absorbent core absorbs bodily fluids, the weight of the bodily fluids generates a downward force on the absorbent main body, and the longitudinal contraction of the leg flaps 46 may apply a downward force to the front waistband member and the rear waistband member. Because the effective length portions 49 of the leg flaps 46 and the absorbent sheet 70 do not overlap in the thickness direction, the downward force transmitted via the leg flaps 46 is less likely to be applied to the absorbent sheet 70, making it easier to prevent the absorbent sheet from shifting downward. This prevents the absorbent sheet from shifting longitudinally, making it easier to keep the absorbent sheet in place around the wearer's waist. This allows the absorbent sheet 70 to be positioned appropriately for the wearer, making it easier to maintain its sweat-absorbing effect.

Furthermore, among the leg elastic members of the leg flaps, the leg elastic members 482 located on the outer side in the width direction may not overlap the joining region R40, while the leg elastic members 481 located on the inner side in the width direction may overlap the joining region R40. Because the leg elastic members 482 located on the outer side in the width direction do not overlap the joining region R40, the leg flaps can flexibly deform when they fit around the wearer's legs, making it easier for the wearer to move their legs. Furthermore, the leg elastic members 481 located on the inner side in the width direction are adjacent to the absorbent core that absorbs bodily fluids, and are therefore more likely to be weighted by bodily fluids. Because the leg elastic members 481 located on the inner side in the width direction overlap the joining region R40, even when the absorbent core becomes heavy due to the absorption of bodily fluids, the leg elastic members can easily continue to pull the absorbent main body toward the waistband member.

The absorbent sheet 70 may be provided over a portion of the entire rear waistband region S2 in the longitudinal direction L. The outer edge 702 of the absorbent sheet 70 may be located more inward in the longitudinal direction L than the outer edge 602 of the side joint 60. The inner edge 701 of the absorbent sheet 70 may be located more inward in the longitudinal direction L than the inner edge 601 of the side joint 60. The rear waistband region S2 may have a first region R1 extending from one outer edge to the other outer edge of the rear waistband region S2 in the width direction W, and extending from the inner edge of the absorbent sheet 70 to the outer edge of the absorbent sheet 70 in the longitudinal direction L. In other words, the first region R1 is the combined region of the region in which the absorbent sheet 70 is disposed and the region in the rear waistband region S2 extending in the width direction from the region in which the absorbent sheet 70 is disposed. The front waist region S1 may also have a second region R2 that is continuous with the first region R1 in the width direction W and extends from one outer edge of the front waist region S1 to the other outer edge in the width direction W. The first region R1 and the second region may be continuous in the width direction W in the pants-like state shown in FIG. 1 . The absorbent sheet 70 may also be disposed across the entire width direction W of the rear waist region S2. The absorbent sheet 70 may have an extension 75 that is disposed outward in the width direction W of the side joint 60. The extension 75 is the portion between the outer edge 70E of the absorbent sheet 70 and the side joint 60.

The disposable diaper 10 has a liquid-impermeable backsheet 50 that is positioned closer to the non-skin-facing side T2 than the absorbent sheet 70. When viewed in a plan view in the thickness direction T, at least a portion of the backsheet 50 may overlap the absorbent sheet. This prevents bodily fluids absorbed by the absorbent sheet from leaking to the non-skin-facing side (outside the diaper). It is sufficient that at least a portion of the backsheet 50 is positioned closer to the non-skin-facing side T2 than the absorbent sheet. The backsheet 50 may have a portion that is not positioned closer to the non-skin-facing side T2 than the absorbent sheet 70.

As shown in FIG. 4, the backsheet 50 may have a first backsheet 51 and a second backsheet 52 located closer to the skin-facing side T1 than the first backsheet 51. The first backsheet 51 may be disposed in each of the front waistline region S1 and the rear waistline region S2. The first backsheet 51 may be located between the first outer nonwoven fabric sheet 35 and the second outer nonwoven fabric sheet 36. The inner edge 511 of the first backsheet 51 may be located outward in the longitudinal direction L from the inner edge of the rear waistline region S2 or the front waistline region S1. The inner edge 511 of the first backsheet 51 in the rear waistline region S2 may be located inward in the longitudinal direction L from the inner edge 701 of the absorbent sheet 70. The outer edge 512 of the first backsheet 51 may be located inward in the longitudinal direction L from the outer edge of the rear waistline region S2 or the front waistline region S1. The outer edge 512 of the first backsheet 51 in the rear waistband region S2 may be located longitudinally inward of the outer edge 702 of the absorbent sheet 70, or may be located longitudinally outward of the outer edge 522 of the second backsheet 52. In this embodiment, the outer edge 512 of the first backsheet 51 constitutes the outer edge of the backsheet. In a modified example, the outer edge 522 of the second backsheet 52 may constitute the outer edge of the backsheet.

The second backsheet 52 may be arranged across the front waistline region S1, the rear waistline region S2, and the crotch region S3. The second backsheet 52 may be arranged on the non-skin-facing side T2 of the absorbent core 45, closer to the skin-facing side T1 than the front waistline member 20 and the rear waistline member 30. The outer edge 522 of the second backsheet 52 is located more inward in the longitudinal direction L than the outer edge of the rear waistline region S2 or the front waistline region S1. The outer edge 522 of the second backsheet 52 in the rear waistline region S2 may be located more inward than the outer edge 702 of the absorbent sheet 70, or more inward than the outer edge 512 of the first backsheet. The first backsheet 51 and the second backsheet 52 are arranged in the center of the width direction W of the disposable diaper 10, and do not necessarily have to be arranged on the sides of the disposable diaper 10 in the width direction W.

In a plan view in the thickness direction, at least a portion of the backsheet 50 may overlap the water-absorbent sheet 70. The water-absorbent sheet 70 may overlap at least a portion of the first backsheet 51, or at least a portion of the second backsheet 52, or may overlap both the first backsheet 51 and the second backsheet 52. The water-absorbent sheet 70 overlaps the backsheet 50 in a region inward in the longitudinal direction L from the outer edge 512 of the first backsheet 51. The water-absorbent sheet 70 overlaps both the first backsheet 51 and the second backsheet in a region inward in the longitudinal direction L from the outer edge 522 of the second backsheet 52. Furthermore, the water-absorbent sheet 70 overlaps the backsheet 50 in a region inward in the width direction W from the outer edge of the first backsheet 51 or the outer edge of the second backsheet 52. Because at least a portion of the absorbent sheet 70 overlaps the back sheet 50, leakage of bodily fluids absorbed by the absorbent sheet 70 can be prevented. Furthermore, when viewed from outside the diaper, the user can tell that at least a portion of the absorbent sheet 70 overlaps the back sheet by the difference in color intensity of the absorbent sheet 70. This makes it easier to feel reassured about leakage of bodily fluids absorbed by the absorbent sheet 70.

The absorbent sheet 70 may have a longitudinal extension 77 extending outward in the longitudinal direction L beyond the outer edge of the backsheet 50. In Figure 3, the longitudinal extension 77 and a widthwise extension 78 (described later) are indicated by different diagonal lines. The longitudinal extension 77 is the portion between the outer edge 512 of the first backsheet 51 and the outer edge 702 of the absorbent sheet 70. The longitudinal extension 77 extends outward in the longitudinal direction L beyond the backsheet 50, making it easily visible from outside the diaper without the backsheet 50 in between. The absorbent sheet 70 is also colored, making it easily visible from outside the diaper. The user can easily recognize the presence of the absorbent sheet 70 by viewing the longitudinal extension 77 from outside the diaper. When the absorbent sheet has a colored portion, the user can easily recognize the presence of the absorbent sheet based on the colored portion of the absorbent sheet 70. This allows the user to feel secure about the absorbency of bodily fluids such as sweat. Because the absorbent sheet 70 is colored and has areas where the absorbent sheet 70 and the back sheet 50 overlap and areas where they do not, it is possible to achieve both visibility of the absorbent sheet and prevention of bodily fluid leakage. This makes it easier for the user to feel secure about both leakage and absorbency.

As shown in Figure 3, the length L21 in the longitudinal direction L of the overlapping region between the water-absorbent sheet 70 and the back sheet 50 may be longer than the length L22 in the longitudinal direction L of the longitudinal extension 77. The length L21 in the longitudinal direction L of the overlapping region between the water-absorbent sheet 70 and the back sheet 50 is the distance in the longitudinal direction L between the outer edge 512 of the first back sheet 51 and the inner edge 701 of the water-absorbent sheet 70. The length L of the longitudinal extension 77 is the distance in the longitudinal direction L between the outer edge 512 of the first back sheet 51 and the outer edge 702 of the water-absorbent sheet 70. The overlapping region between the water-absorbent sheet 70 and the back sheet 50 is longer than the longitudinal extension 77, thereby improving the effect of suppressing leakage of bodily fluids. The water-absorbent sheet 70 is colored, making it easily noticeable against other sheets, etc. Therefore, even if the length of the longitudinal extensions 77 is short, the user can easily sense the presence of the water-absorbent sheet 70 and feel reassured about its absorbency. More preferably, the length of the longitudinal extensions 77 in the longitudinal direction L may be less than 30% of the total length of the water-absorbent sheet 70 in the longitudinal direction L. The water-absorbent sheet 70 overlaps the back sheet 50 over an area in the longitudinal direction L that is 70% or more of the total length of the water-absorbent sheet 70, ensuring the prevention of leakage of bodily fluids. This makes it easier to achieve both visibility and leak-proofness of the water-absorbent sheet 70.

The absorbent sheet 70 may have a widthwise extension 78 that extends outward in the width direction beyond the outer edge of the backsheet 50. The widthwise extension 78 is the portion between the outer edge of the first backsheet 51 and the outer edge of the absorbent sheet, longitudinally outward from the outer edge 522 of the second backsheet 52. The widthwise extension 78 is the portion between the outer edge of the first backsheet 51 and the outer edge of the second backsheet, the outer edge of which is located outward in the width direction, and the outer edge of the absorbent sheet, longitudinally inward from the outer edge 522 of the second backsheet 52. The widthwise positional relationship between the outer edge of the first backsheet 51 and the outer edge of the second backsheet is not limited. The provision of this widthwise extension 78 allows the user to visually recognize the absorbent sheet 70, which extends outward in the width direction W beyond the backsheet 50, from outside the diaper, making it easy for the user to recognize the presence of the absorbent sheet. This provides a sense of security for the user's absorbency.

As shown in FIG. 3, the width extension portion 78 may extend widthwise outward beyond the center CL between the outer edge of the backsheet and the outer edge of the disposable diaper. The width extension portion 78 is positioned in at least half of the region outward in the width direction W from the backsheet 50. This makes it easier for the user to see the absorbent sheet that extends widthwise outward from the backsheet. More preferably, the absorbent sheet 70 may be positioned across the entire width of the disposable diaper. Because the absorbent sheet is positioned across the entire width of the disposable diaper, the absorbent sheet is more easily visible to the user. This makes it easier for the user to recognize the presence of the absorbent sheet, giving them a sense of security regarding its absorbency.

The longitudinal extensions 77 and width extensions 78 of the absorbent sheet 70 form non-overlapping regions that do not overlap with the back sheet. In a stretched state, the area of the non-overlapping regions is preferably 60% or more of the total area of the absorbent sheet. In a stretched state, the absorbent sheet does not overlap with the back sheet over an area that is 60% or more of its total area. This makes it easier to ensure the visibility of the absorbent sheet 70.

In a plan view in the thickness direction, the elastic member 32 may overlap the longitudinal extension 77 and be positioned on the non-skin-facing side of the longitudinal extension 77. The L value in the L*a*b* color space of the longitudinal extension 77 when the disposable diaper in its natural state is viewed from the non-skin-facing side may be 82 or more, preferably 85 or more. The L value in the L*a*b* color space of the longitudinal extension 77 is not the L value of the absorbent sheet 70 itself, but the L value measured from the non-skin-facing side of the disposable diaper. The state when the disposable diaper in its natural state is viewed from the non-skin-facing side is the state when the disposable diaper is left for 24 hours in an atmosphere of 60%±5% RH with the non-skin-facing side of the rear waist region facing up and then viewed. The longitudinally extending portions 77 of the water-absorbent sheet 70 are visible through the first outer nonwoven fabric sheet 35 and the second outer nonwoven fabric sheet 36. When viewing the water-absorbent sheet 70 from outside the diaper, the user can see the longitudinally extending portions 77 as well as the stretchable members 32. If the stretchable members 32 are too conspicuous, the user may feel uncomfortable due to the stretchable members 32. Specifically, if the stretchable members 32 are too conspicuous, the stretchable members may be emphasized, which may cause discomfort compared to diapers in which the stretchable members are less conspicuous, or the stretchability may be overemphasized, leaving marks on the skin due to the stretch, making the diaper feel unfriendly to the skin, or giving the user a chemical-like, unfriendly feeling. By setting the L value of the longitudinally extending portions in the L*a*b* color space to 85 or more when viewed from the non-skin-facing side of the diaper, the user can prevent the stretchable members 32 from being too conspicuous and thus reduce the discomfort caused by the stretchable members 32. More preferably, the L value in the L*a*b* color space of the longitudinal extension 77 may be equal to or less than 91.6, which is the L value of the stretchable member 32. This makes the stretchable member 32 less noticeable relative to the longitudinal extension 77. The L value of the longitudinal extension can be determined by measuring the color of the object to be measured using a commercially available colorimeter and quantifying the value based on the CIE 1976 (L*a*b*) color space specified in JIS Z 8729.

Preferably, the absorbent sheet 70 may have a blue base. A blue base for the absorbent sheet 70 gives it a cool appearance and enhances the feeling of freshness. The stretchable member 32 may have a white base. A white base for the stretchable member 32 makes it less noticeable against the absorbent sheet 70, further reducing the sense of discomfort. A white base is an L value of 90.0 or greater in the (L*a*b*) color space, and a blue base is an L value of 0 or less and an a value of 20 or less in the (L*a*b*) color space.

Next, an evaluation of the discomfort felt by the absorbent sheet thus constructed will be described. Ten subjects who regularly wear disposable diapers were asked to visually inspect the disposable diapers of Examples 1 to 5 and Comparative Examples 1 and 2 in their natural state, and a questionnaire was conducted regarding the discomfort felt by the stretchable member in accordance with the following evaluation criteria. The (L*a*b*) values of the disposable diapers used in the evaluation are values of the longitudinally extending portion measured from the non-skin-facing side of the disposable diaper in its natural state. In this evaluation, the L value of the (L*a*b*) color space for the stretchable member 32 was 91.6, the a value was -0.62, and the b value was -1.81.
(Judgment criteria)
Good: The stretchable member cannot be recognized, or the stretchable member can be recognized but does not cause discomfort.
Poor: The stretchable member is recognizable, causing discomfort.
From the survey results, diapers for which 80% or more of the 30 subjects gave the rating "good" were given an overall rating of ◎, diapers for which 60% or more of the subjects gave the rating "good" were given an overall rating of ○, and diapers for which less than 60% of the subjects gave the rating "good" were given an overall rating of ×.

As shown in Table 1, the disposable diapers of Examples 1 to 5 are less likely to experience discomfort due to the stretchable member. Therefore, it is preferable that the L value of the longitudinal extension 77 is 82 or more. Furthermore, it was found that the disposable diapers of Examples 1 to 4 were less likely to cause discomfort in 80% or more of users. Therefore, it is more preferable that the L value of the longitudinal extension 77 is 85 or more.

Next, the joining of the front waist region S1 and the rear waist region S2 near the side joining portion of the disposable diaper configured as described above will be described with reference to Figures 6 to 8. Figure 6 shows the CC cross section shown in Figure 1, Figure 7 shows the D-D cross section shown in Figure 1, and Figure 8 shows the E-E cross section shown in Figure 1. Figures 6 and 7 show cross sections of the area where the absorbent sheet 70 is arranged, and Figure 8 shows a cross section of the area where the absorbent sheet 70 is not arranged.

The disposable diaper 10 has a non-joined region NR where the front waist region S1, which is the second waist region, is not joined to the extension 75 of the absorbent sheet 70. The non-joined region NR is a region where, in the pants-type state, the surface of the extension 75 facing the front waist region S1 is not joined to the surface of the front waistline member 20 facing the rear waist region S2. The non-joined region NR may be located in a region extending from the outer edge of the extension 75 toward the inside in the width direction W, or may be continuous from the outer edge of the extension 75 to the side joint 60. The outer edge of the non-joined region NR is the outer edge of the extension 75, i.e., the outer edge 70E of the absorbent sheet 70. The inner edge of the non-joined region NR may be adjacent to the side joint 60 or may be spaced apart from the side joint 60 in the width direction W.

In the region extending from the outer edge of the extension portion 75 toward the inside in the width direction W, the extension portion 75 is not joined to the front waist region S1. Therefore, in the region extending from the outer edge of the extension portion 75 toward the inside in the width direction W, the extension portion 75 is spaced apart from the front waist region S1, making it more visible from the outside of the diaper. In particular, as shown in the C-C cross section of Figure 6, in the region where the absorbent sheet 70 is not covered by the folded portion 35F of the first outer nonwoven fabric sheet 35, the extension portion 75 is exposed and more easily visible from the outside of the diaper. Furthermore, because the absorbent sheet 70 is colored, the user can easily recognize the absorbent sheet 70. The extension portion 75 of the absorbent sheet 70 makes it easy for the user to recognize its presence. The user can recognize that the absorbent sheet 70, which can absorb body fluids, is located separately from the absorbent core, and can feel reassured about the absorbency of body fluids such as sweat. Additionally, the user can use the extension 75 of the absorbent sheet 70 as a marker to identify the outer widthwise edge of the disposable diaper, making it easier to determine if the disposable diaper is misaligned in the widthwise direction when putting it on. This allows the user to put the disposable diaper on in the appropriate position relative to their body.

Furthermore, the contractile force in the width direction W of the front waist region S1 constituting the second waist region may be higher than the contractile force in the width direction W of the rear waist region S2 constituting the first waist region. Because the front waist region S1 is more likely to contract in the width direction than the rear waist region S2, the outer edge of the rear waist region S2 is pulled toward the front waist region S1 when worn. As a result, the extension portions 75 of the absorbent sheet 70 are pulled toward the front, making them more noticeable when viewed from the front. In other words, the extension portions 75 are biased toward the front or rear rather than the sides of the wearer's body, making them more noticeable than a configuration in which they are located on the sides. This makes the extension portions 75 of the absorbent sheet 70 more easily noticeable to the user, and provides a greater sense of security regarding the absorbency of bodily fluids. To ensure that the extension portions 75 are easily noticeable to the user, the length of the extension portions 75 in the width direction W is preferably 5 mm or greater.

Disposable diapers configured in this manner can be manufactured, for example, by the following manufacturing method. First, a front continuous body in which the front waistband member is continuous in the width direction and a rear continuous body in which the rear waistband member is continuous in the width direction are transported, and components such as the absorbent main body 40 are arranged so as to straddle the front and rear continuous bodies. Next, the front continuous body and the absorbent main body are folded around a fold line extending in the width direction so that the front and rear continuous bodies overlap. Side joints are then formed, and the continuous body is cut along the outer edges of the front waistband region and the outer edges of the rear waistband region. This produces a pants-type disposable diaper.

When cutting the front and rear continuous bodies, they are cut with a cutting device such as a cutter while they are overlapping each other. Therefore, the front and rear continuous bodies are welded together during cutting, forming a second side joint 61 where the front continuous body (front waist region) and the rear continuous body (rear waist region) are joined together widthwise outward from the side joint (see Figures 1 and 8). At this time, it is difficult to join the pulp sheet 71 containing pulp fibers to the exterior nonwoven fabric sheet, but it is easy to join the exterior nonwoven fabric sheets together. Therefore, as shown in Figures 6 and 7, the second side joint 61 is not formed by cutting in the area where the absorbent sheet 70 containing the pulp sheet 71 is placed. On the other hand, as shown in Figure 8, the second side joint 61 is formed by cutting in the area where the absorbent sheet 70 is not placed.

A second side joint 61 may be formed in the regions outside and inside the absorbent sheet 70 in the longitudinal direction L. The second side joint 61 is the portion where the front waist region S1 and the rear waist region S2 are joined, outside the side joint 60 in the width direction W. The second side joint 61 may be spaced apart in the width direction W from the side joint 60. With this configuration, the side joint 60 and the second side joint 61 are provided in the region outside the absorbent sheet 70 in the longitudinal direction L. In the region outside the absorbent sheet in the longitudinal direction, it is difficult for fingers or other objects to insert between the first waist region and the second waist region from the outside of the diaper, and the second side joint 61 protects the joined state of the side joint 60. This prevents the side joint 60 from unintentionally breaking during use.

The nonwoven fabric sheet includes a first-side nonwoven fabric sheet located closer to the first waist region in the thickness direction than the pulp sheet 71 in the region where the side joint 60 is provided, and a second-side nonwoven fabric sheet located closer to the second waist region in the thickness direction than the pulp sheet 71 in the region where the side joint 60 is provided. In the region shown in Figure 6, the first-side nonwoven fabric sheet is composed of the water-absorbent nonwoven fabric sheet 72, the first exterior nonwoven fabric sheet 35 in the rear waist region S2, and the second exterior nonwoven fabric sheet 36 in the rear waist region S2, while the second-side nonwoven fabric sheet is composed of the water-absorbent nonwoven fabric sheet 72, the first exterior nonwoven fabric sheet 35 in the front waist region S1, and the second exterior nonwoven fabric sheet 36 in the front waist region S1. In the region shown in Figure 7, the first-side nonwoven fabric sheet is composed of a water-absorbent nonwoven fabric sheet 72, one first exterior nonwoven fabric sheet 35 in the front waist region S1, two first exterior nonwoven fabric sheets 35 in the rear waist region S2, and a second exterior nonwoven fabric sheet 36 in the rear waist region S2. In the region shown in Figure 7, the second-side nonwoven fabric sheet is composed of a water-absorbent nonwoven fabric sheet 72, the first exterior nonwoven fabric sheet 35 in the front waist region S1, and a second exterior nonwoven fabric sheet 36 in the front waist region S1. Note that when the water-absorbent sheet 70 does not have a water-absorbent nonwoven fabric sheet, the first-side nonwoven fabric sheet and the second-side nonwoven fabric sheet may be composed of at least one of the first exterior nonwoven fabric sheet and the second exterior nonwoven fabric sheet.

The basis weight of the first-side nonwoven fabric sheet and the basis weight of the second-side nonwoven fabric sheet may be higher than the basis weight of the pulp sheet 71. The basis weight of the first-side nonwoven fabric sheet is the total basis weight of the nonwoven fabric sheets that make up the first-side nonwoven fabric sheet. The basis weight of the second-side nonwoven fabric sheet is the total basis weight of the nonwoven fabric sheets that make up the second-side nonwoven fabric sheet. Because the basis weights of the first-side nonwoven fabric sheet and the second-side nonwoven fabric sheet are relatively high, it is easy to form the second side joint 61 by joining the nonwoven fabric sheets together when cutting, and it is also easy to maintain the joined state of the second side joint 61. This makes it easy to maintain the joined state of the outer edge of the front waist region S1 and the outer edge of the rear waist region while still providing the bodily fluid absorbency of the pulp sheet 71.

The side joints 60 are formed on the non-skin-facing side T2 of the diaper by thermal welding or the like. The formation of the side joints 60 fuses thermoplastic fibers such as nonwoven fabric. The pulp sheet 71 contains pulp fibers and is less susceptible to welding than nonwoven fabric. Therefore, the bond strength of the portions of the side joints 60 that do not overlap with the pulp sheet 71 is higher than the bond strength of the portions of the side joints that do overlap with the pulp sheet 71. The portions of the side joints 60 that do not overlap with the pulp sheet 71 are the portions located longitudinally outboard of the absorbent sheet 70 and the portions located longitudinally inboard of the absorbent sheet 70. As shown in Figure 6 and other figures, in the region where the side joints 60 are formed, the pulp sheet 71, the absorbent nonwoven fabric sheet 72, the first exterior nonwoven fabric sheet 35, and the second exterior nonwoven fabric sheet 36 overlap in the thickness direction T.

The water-absorbent sheet 70 is positioned in the rear waistband region S2 and is bonded to the rear waistband region S2 with an adhesive or the like. Therefore, with the side joint 60 formed, the bond between the water-absorbent sheet 70 and other sheets is more likely to be maintained on the rear waistband region S2 side in the thickness direction T than the pulp sheet 71. On the other hand, the bond between the water-absorbent sheet 70 and other sheets may be less likely to be maintained on the front waistband region S1 side in the thickness direction T than the pulp sheet 71. To maintain the bond between the water-absorbent sheet 70 and the front waistband region S1, the basis weight of the pulp sheet 71 is preferably lower than the basis weight of the second-side nonwoven fabric sheet positioned closer to the second waistband region than the pulp sheet 71. Because the basis weight of the pulp sheet 71 is lower than the basis weight of the second-side nonwoven fabric sheet, the second-side nonwoven fabric sheet maintains the bond at the side joint 60, preventing unintentional tearing of the side joint 60 during use.

As shown in Figure 2, the distance L1 between the outer edge 702 of the absorbent sheet 70 and the outer edge 602 of the side joint 60 may be shorter than the distance L2 between the inner edge 701 of the absorbent sheet 70 and the inner edge 601 of the side joint 60. When removing a disposable diaper from a wearer, the side joint 60 is generally torn from the outer edge 602 of the side joint 60 toward the inside in the longitudinal direction L. At this time, the user will notice that the strength of the side joint is relatively high in the region outside the absorbent sheet 70 in the longitudinal direction L, and that the strength of the side joint 60 is relatively low in the region where the absorbent sheet 70 is located. Because the distance L1 between the outer edge 702 of the absorbent sheet 70 and the outer edge 602 of the side joint 60 is shorter than the distance between the inner edge 701 of the absorbent sheet 70 and the inner edge 601 of the side joint 60, the user can quickly reach the easy-to-tear area when tearing the side joint from the outer edge in the longitudinal direction toward the inside of the side joint. This makes it easier for the user to tear the side joint 60.

The disposable diaper 10 is also designed to allow the absorbent sheet 70 to easily adhere to the skin. By allowing the absorbent sheet 70 to adhere to the skin, it is possible to improve the absorbency of bodily fluids such as sweat. Next, the design that allows the absorbent sheet 70 to easily adhere to the skin will be described in detail.

The contractile force of the first region R1 in the width direction W may be lower than the contractile force of the second region R2 in the width direction. When worn, the first region R1 and the second region R2 contract in the width direction W compared to the stretched state shown in Figure 2, etc., and the first region R1 is pulled toward the second region R2. Fewer wrinkles form in the first region R1 compared to the second region R2, increasing the contact area between the first region R1 and the skin. This allows the absorbent sheet 70 to adhere closely to the skin, improving the absorbency of body fluids such as sweat.

Furthermore, the contractile force in the width direction W of the rear waistband region S2 may be lower than the contractile force in the width direction of the front waistband region S1. When worn, the rear waistband region S2 is pulled toward the front waistband region S1. This reduces the number of wrinkles formed in the rear waistband region S2, making it easier for the rear waistband region S2 to adhere to the skin. This allows the absorbent sheet 70 to adhere to the skin, improving absorbency.

In the present invention, the wearing state refers to a state in which a disposable diaper in which the front waist region S1 and the rear waist region S2 are continuous in the width direction W via the side joint portion 60 is worn on the tubular body 100 so that it is 77% of the stretched state. Figure 9 is a schematic diagram showing the state in which the diaper is worn on the tubular body 100 so that it is 77% of the stretched state. Figure 9 shows the disposable diaper and the tubular body as viewed from an extension of the central axis of the tubular body 100. The state in which the diaper is worn on the tubular body 100 so that it is 77% of the stretched state is as follows. The front waist region S1 and the rear waist region S2 are stretched in the width direction W to remove wrinkles in the front waist region S1 and the rear waist region S2, and the length L31 (see FIG. 2 ) between the side joints 60 in the front waist region S1 (the length between the inner edge of the left side joint and the inner edge of the right side joint) and the length L32 between the side joints 60 in the rear waist region S2 are measured. The sum of the length L31 between the side joints 60 in the front waist region S1 and the length L32 between the side joints 60 in the rear waist region S2 is defined as the length of the disposable diaper 10 in a stretched state when attached to the tubular body 100. Next, the disposable diaper 10 is attached to the tubular body 100, whose periphery is 77% of the length in the stretched state. This state is defined as the state in which the disposable diaper 10 is attached to the tubular body 100 so that the periphery is 77% of the length in the stretched state. The length L of the cylindrical body 100 in the longitudinal direction is at least equal to or greater than the longitudinal length of the side joint portion 60. The surface material of the cylindrical body 100 can be a silicone PET separator (Nippa Corporation, PET38*1-B, C70905-13), and the friction coefficient can be less than 1 μs. The friction coefficient is a static friction coefficient and can be measured by applying a measuring element to the surface of the cylindrical body using a portable friction meter Muse (HEIDON, Nisshin Machinery Co., Ltd.). Measurements are taken at 5 to 10 locations, and the average value is taken as the friction coefficient.

When worn on a tubular body so that the length is 77% of the stretched state, the length L41 (see Figure 9) between the side join portions 60 in the front waist region S1 may be shorter than the length L42 between the side join portions 60 in the rear waist region S2. When designing a disposable diaper, it is assumed that the waist circumference dimension that is 77% of the widthwise length in the stretched state is included in the wearer's waist circumference dimension in the worn state. The ratio of the length L42 between the side join portions 60 in the rear waist region S2 to the length L41 between the side join portions 60 in the front waist region S1 in the worn state is higher than the ratio of the length L32 between the side join portions 60 in the rear waist region S2 to the length L31 between the side join portions 60 in the front waist region S1 in the stretched state.

In this embodiment, the length L31 between the side joints 60 in the front waistband region S1 in the stretched state and the length L32 between the side joints 60 in the rear waistband region S2 in the stretched state are the same, as shown in FIG. 2. Therefore, the ratio of the length between the side joints 60 in the rear waistband region S2 to the length between the side joints 60 in the front waistband region S1 in the stretched state is 1.0. Also, as shown in FIG. 9, the side joints 60 are biased toward the front waistband region S1 in the worn state. The length L42 between the side joints 60 in the rear waistband region S2 in the worn state is longer than the length L41 between the side joints 60 in the front waistband region S1 in the worn state. Therefore, the ratio of the length L42 between the side joints 60 in the rear waistband region S2 to the length L41 between the side joints 60 in the front waistband region S1 in the worn state is greater than 1.0. Because the side joints 60 are biased toward the front waistband region S1 when worn, the rear waistband region S2 has fewer wrinkles than the front waistband region S1 and is more likely to fit snugly against the skin. This allows the absorbent sheet 70 to fit snugly against the skin, improving its ability to absorb bodily fluids such as sweat. Furthermore, when worn on a cylindrical body at 77% of its stretched state, the extensions 75 of the absorbent sheet 70 are biased toward the front waistband region S1. This makes the extensions 75 more visible from the front of the body when worn.

The contractile force in the width direction of the region where the water-absorbent sheet 70 is disposed may be higher than the contractile force of the region located on the longitudinal outside of that region. As shown in Figure 4, the region extending from the outer edge 702 in the longitudinal direction L of the water-absorbent sheet 70 to the outside in the longitudinal direction L is referred to as the outer region R4, and the region extending from the inner edge 701 in the longitudinal direction L of the water-absorbent sheet 70 to the inside in the longitudinal direction L is referred to as the inner region R3. The contractile force in the width direction of the region where the water-absorbent sheet 70 is disposed may be higher than the contractile force in the width direction W of at least one of the outer region R4 and the inner region R3. Note that the region where the water-absorbent sheet 70 is disposed is the region that overlaps with the water-absorbent sheet 70 in a plan view in the thickness direction. Because the contractile force of the region where the water-absorbent sheet 70 is disposed is higher than the contractile force of either the outer region R4 or the inner region R3, the region where the water-absorbent sheet 70 is disposed easily fits the body without floating off the wearer's skin. Preferably, the contractile force in the width direction W of the region where the water-absorbent sheet 70 is arranged may be higher than the contractile force in the width direction W of the outer region R4. This allows the region where the water-absorbent sheet 70 is arranged to fit the body better than the outer region R4, making it less likely for the water-absorbent sheet 70 to lift up from the skin on the outer region R4 side, and preventing body fluids absorbed by the water-absorbent sheet from leaking through the waist-opening 62. More preferably, the contractile force in the width direction of the region where the water-absorbent sheet is arranged may be higher than the contractile force in the width direction of the outer region R4 and the contractile force in the width direction of the inner region R3. This allows the water-absorbent sheet to fit the body more easily. This allows the water-absorbent sheet to absorb body fluids more efficiently, improving absorbency.

When viewed in a plan view in the thickness direction, the tape member 80 may be positioned so as to overlap at least a portion of the water-absorbent sheet 70. The tape member increases the rigidity of the water-absorbent sheet 70 in the area where it overlaps. This makes the water-absorbent sheet 70 less likely to wrinkle, and allows the water-absorbent sheet 70 to adhere more closely to the skin.

As shown in FIG. 3 , the inner edge 801 of the tape member 80 may be positioned inward in the longitudinal direction L from the center of the absorbent sheet 70 in the longitudinal direction L. The absorbent sheet 70 is preferably positioned in an area that easily absorbs sweat, and is preferably positioned across the wearer's gluteal cleft and back. The tape member 80 is positioned inward in the longitudinal direction L from the center of the absorbent sheet 70, and is easily positioned in a position that corresponds to the wearer's gluteal cleft. More preferably, the inner edge 801 of the tape member 80 may be positioned inward in the longitudinal direction from the inner edge 701 of the absorbent sheet 70. The tape member 80 is easily positioned in a position that corresponds to the wearer's gluteal cleft. Therefore, the absorbent sheet 70 overlapping the tape member 80 fits into the depression of the gluteal cleft, improving absorbency.

In a plan view in the thickness direction, the tape member 80 may overlap the widthwise center of the rear waistband region S2. The tape member 80 overlaps the widthwise center of the rear waistband region S2, making it easier for the tape member 80 to fit into the hollow of the gluteal cleft when worn. More preferably, the tape member 80 may be positioned across the center of the widthwise direction W of the rear waistband region S2. The tape member 80 will be easier to fit into the hollow of the gluteal cleft within a certain range extending left and right from the widthwise center of the gluteal cleft. The absorbent sheet 70 overlapping the tape member 80 fits more closely to the skin, further improving absorbency.

In a plan view in the thickness direction, at least a portion of the absorbent sheet 70 may overlap the outer longitudinal edge of the absorbent core 45 on the skin-facing side of the absorbent core 45. More specifically, the absorbent sheet 70 and the absorbent core 45 may overlap in the longitudinal direction L in a region from the inner edge of the absorbent sheet to the outer edge of the absorbent core, and in the width direction W, in a region inside the outer edge of the absorbent core 45. The absorbent core 45 is layered with an absorbent material that absorbs bodily fluids, and the thickness of the absorbent core is generally greater than the thickness of other diaper components such as the backsheet. The absorbent sheet 70 overlaps the outer longitudinal edge of the absorbent core, and is positioned closer to the wearer due to the thickness of the absorbent core. This allows the absorbent sheet to fit closely to the wearer, improving absorbency. The outer edge of the absorbent core is generally positioned to overlap the vicinity of the wearer's gluteal cleft. The absorbent sheet overlaps the outer edge of the absorbent core and is positioned so as to fit into the gluteal cleft. This further improves absorbency.

In a modified example, the absorbent sheet 70 may be spaced apart from the absorbent core 45 in the longitudinal direction L. By spaced apart from the absorbent core 45 in the longitudinal direction, i.e., by not overlapping the absorbent core 45 and the absorbent sheet 70 in a plan view in the thickness direction, bodily fluids absorbed by the absorbent core 45 are less likely to be transferred to the absorbent sheet 70. This further reduces leakage of bodily fluids from the absorbent sheet 70.

The length L12 between the outer edge of the rear waistband region S2 and the outer edge of the absorbent body 40 may be longer than the length L11 between the outer edge of the front waistband region S1 and the outer edge of the absorbent body 40. The absorbent body 40 is located in the crotch region S3 and is easily pinched between the legs when worn, resulting in compression in the width direction W. The absorbent body 40 is positioned closer to the front waistband region S1 than the rear waistband region S2 in the longitudinal direction L. Therefore, the rear waistband region S2 is less affected by compression of the absorbent body 40. The absorbent sheet 70 located in the rear waistband region S2 is more likely to remain in close contact with the skin.

The present invention has been described in detail using the above-mentioned embodiments, but it will be clear to those skilled in the art that the present invention is not limited to the embodiments described herein. The present invention can be implemented in modified and altered forms without departing from the spirit and scope of the present invention as defined by the claims. Therefore, the descriptions in this specification are intended for illustrative purposes only and are not intended to be limiting of the present invention.

The present invention is aimed at providing a disposable diaper in which the absorbent sheet adheres closely to the wearer's skin, improving absorbency.

10 Disposable diaper 20 Front waistband member 30 Rear waistband member 35 First exterior nonwoven fabric sheet (nonwoven fabric sheet)
36 Second exterior nonwoven fabric sheet (nonwoven fabric sheet)
40 Absorbent body 45 Absorbent core 46 Leg flap 49 Effective length 50 Back sheet 51 First back sheet 52 Second back sheet 60 Side joint portion 70 Absorbent sheet 71 Pulp sheet 72 Absorbent nonwoven fabric sheet (nonwoven fabric sheet)
75 Extension portion 80 Tape member S1 Front waist region S2 Rear waist region S3 Crotch region L Longitudinal direction W Width direction T1 Skin-facing side T2 Non-skin-facing side

Claims (10)

a longitudinal direction and a width direction that are perpendicular to each other;
a front waist region, a rear waist region, and a crotch region disposed between the front waist region and the rear waist region;
an absorbent main body disposed at least in the crotch region;
a water-absorbent sheet disposed in a first waist region, which is one of the front waist region and the rear waist region;
a liquid-impermeable back sheet disposed on the non-skin-facing side of the water-absorbent sheet;
A disposable diaper having a side joining portion joining an outer portion of the front waist region and an outer portion of the rear waist region,
the absorbent sheet has at least one of an outer region extending from an outer edge of the absorbent sheet in the longitudinal direction to the outside in the longitudinal direction, and an inner region extending from an inner edge of the absorbent sheet in the longitudinal direction to the inside in the longitudinal direction,
The disposable diaper has a contractile force in the width direction of the region where the water-absorbent sheet is arranged that is higher than a contractile force in the width direction of at least one of the outer region and the inner region . The disposable diaper according to claim 1, wherein the absorbent sheet is joined to a member located on the non-skin-facing side of the absorbent sheet by an adhesive means. the water-absorbent sheet has a longitudinally extending portion that extends outward in the longitudinal direction beyond the outer edge of the back sheet,
3. The disposable diaper according to claim 1, wherein the length in the longitudinal direction of the region where the absorbent sheet and the back sheet overlap is longer than the length in the longitudinal direction of the longitudinally extending portion. the water-absorbent sheet has a widthwise extending portion extending outward in the width direction beyond the outer edge of the back sheet, and a lengthwise extending portion extending outward in the lengthwise direction beyond the outer end edge of the back sheet,
The longitudinally extending portion and the widthwise extending portion have a non-overlapping region that does not overlap with the backsheet,
4. The disposable diaper according to claim 1, wherein the area of the non-overlapping region is 60% or more of the area of the entire absorbent sheet in a stretched state. A disposable diaper according to any one of claims 1 to 4, wherein the distance between the outer edge of the absorbent sheet and the outer edge of the side joint portion in the longitudinal direction is shorter than the distance between the inner edge of the absorbent sheet and the inner edge of the side joint portion. the first waist region includes a first exterior nonwoven fabric sheet, a second exterior nonwoven fabric sheet disposed closer to the skin than the first exterior nonwoven fabric sheet, and a stretchable member stretchable in the width direction;
the first exterior nonwoven fabric sheet has a folded-back portion that is folded back toward the skin-facing surface from the waist-opening as a base point,
The disposable diaper according to claim 1 , wherein the folded-back portion overlaps the absorbent sheet and the stretchable member. The first waist region has a stretchable member that is stretchable in the width direction,
The disposable diaper according to claim 1 , wherein a plurality of the stretchable members are arranged in the outer region. The absorbent main body has an absorbent core and leg flaps arranged on the outer side of the absorbent core in the width direction and having leg elastic members that stretch in the longitudinal direction,
the absorbent main body is joined to a first waist member disposed in the first waist region at a joining region;
The disposable diaper according to claim 1 , wherein, in a plan view in the thickness direction, effective length portions of the leg flaps do not overlap the absorbent sheet but overlap the joining region. The absorbent main body has an absorbent core and leg flaps arranged on the outer side of the absorbent core in the width direction and having leg elastic members that stretch in the longitudinal direction,
the absorbent main body is joined to a first waist member disposed in the first waist region at a joining region;
8. The disposable diaper according to claim 1, wherein, in a plan view in the thickness direction, outer leg elastic members located on the outer side in the width direction among the leg elastic members do not overlap the joining region, and inner leg elastic members located on the inner side in the width direction among the leg elastic members overlap the joining region. A laminated region in which the back sheet overlaps in the thickness direction is provided,
The disposable diaper according to claim 1 , wherein at least a portion of the laminated region overlaps the absorbent sheet.