JP3253031U - absorbent articles - Google Patents

Abstract

[Problem] To provide an absorbent article that can improve wearing comfort while minimizing the gap between the feel caused by the sheet on the non-skin side and the wearing comfort caused by the sheet on the skin side.
[Solution] The absorbent article 1 comprises waistband portions 2, 3 and an absorbent body 10. The waistband portion includes a stretchable sheet that is stretchable in the width direction, and non-stretchable adjacent sheets 22, 23, 32, 33 that are adjacent to the skin side and non-skin side of the stretchable sheet and are non-stretchable. The skin-side sheets 22, 32 that form the skin side of the waistband portion and the non-skin side sheets 23, 33 that form the non-skin side are non-stretchable adjacent sheets. The skin-side sheets and non-skin-side sheets are separate sheets. The larger of the skin-side and non-skin-side sheets has an average basis weight 1.0 to 1.3 times that of the smaller at 80% elongation. The larger of the fibers that make up the skin-side and non-skin-side sheets has an average fiber diameter 1.0 to 1.5 times that of the smaller.
[Selected Figure] Figure 1

Description

This invention relates to an absorbent article.

Absorbent articles are known that use a stretchable or elastic sheet around the waistband to improve comfort and a more underwear-like appearance. For example, Patent Document 1 discloses an absorbent article with an absorbent body that absorbs body waste. The absorbent article has an elastic film stretch structure in which an elastic film is laminated between a first sheet layer and a second sheet layer, and the first sheet layer and the second sheet layer are joined at a number of spaced-apart sheet joints through through-holes that penetrate the elastic film. The region having the elastic film stretch structure has a stretchable region that can stretch in one direction and a non-stretchable region located on at least one side of the stretchable region in the stretchable direction. The stretchable region has a linearly continuous portion of the elastic film along the stretchable direction, and contracts in the stretchable direction due to the contractile force of the elastic film, while being extensible in the stretchable direction. The non-stretchable region has a continuous elastic film along the stretchable direction, but does not have a linearly continuous portion along the stretchable direction due to the presence of through-holes. Patent Document 1 states that the non-stretchable region of the elastic film stretch structure can improve the product's appearance and flexibility, preventing them from deteriorating.

Patent Document 2 also discloses a stretchable nonwoven fabric. The stretchable nonwoven fabric has a longitudinal direction and a transverse direction perpendicular to the longitudinal direction, and has a plurality of sparse band-like regions and a plurality of dense band-like regions extending in the longitudinal direction, alternately and continuously formed in the transverse direction on both sides, with the dense band-like regions on one side and the dense band-like regions on the other side alternately formed in the transverse direction. The stretchable nonwoven fabric is made of a mixture of extensible fibers and stretchable fibers. The extensible fibers include extensible fibers that are partially stretched between the dense band-like regions on the one side and the dense band-like regions on the other side. The dense band-like regions on the one side and the dense band-like regions on the other side are spaced apart by passing between a pair of gear rolls having convex gear teeth spaced 4 to 7 mm apart from each other. The sparse band-like regions are formed flat by passing between at least a pair of guide rollers. The average fiber diameter of the fibers that make up the partially stretched extensible fiber is smaller than the average fiber diameter of the extensible fibers in the dense band region.

JP 2017-64224 A Patent No. 5342751

According to the inventor's research, in an absorbent article, if the average basis weight or average fiber diameter of the constituent fibers of the non-skin-side (outer) sheet and the skin-side (inner) sheet of the waistband differ, the appearance and feel of the non-skin-side surface and the skin-side surface of the waistband are likely to differ accordingly. Furthermore, if sheets with different average basis weights or average fiber diameters of the constituent fibers are used for the skin-side (inner) sheet of the waistband, the comfort of wearing them will also likely differ.

Before putting on the absorbent article, the wearer typically looks at and touches the non-skin-facing surface of the waistband and predicts the comfort of the article, such as its softness, based on its appearance and feel. Therefore, if the non-skin-facing surface and the skin-facing surface have different appearances and feel, and the wearer predicts the comfort based on the appearance and feel of the non-skin-facing surface before putting on the article, there may be a discrepancy between the predicted comfort and the actual comfort, which could cause the wearer to feel uncomfortable.

Patent Document 1 does not particularly consider the relationship between the average basis weight and constituent fibers of the non-skin-side sheet (second sheet layer) and the skin-side sheet (first sheet layer) in the waistband portion. Furthermore, because the through-holes are formed from one side of the skin-side sheet to the other, the appearance and feel of the non-skin-side surface and the skin-side surface are likely to differ.

The objective of this invention is to provide an absorbent article that improves comfort while minimizing the gap between the feel of the non-skin-side sheet and the comfort of the skin-side sheet.

One aspect of the present invention is an absorbent article that has a longitudinal direction, a width direction, and a thickness direction that are perpendicular to one another when deployed, and that includes a waist section that covers the waist of the wearer, and an absorbent main body that covers the crotch area and includes an absorbent body. The waist section includes a stretchable sheet that extends in the width direction and is stretchable in the width direction, and a non-stretchable adjacent sheet that is adjacent to at least one of the skin side and non-skin side of the stretchable sheet and is non-stretchable. The skin side sheet that constitutes the skin side of the waist section and the non-skin side sheet that constitutes the non-skin side are one of the sheets is one of the non-stretchable adjacent sheet and the stretchable sheet, the other of the skin-side sheet and the non-skin-side sheet is the non-stretchable adjacent sheet, the skin-side sheet and the non-skin-side sheet are nonwoven fabrics, the larger of the skin-side sheet and the non-skin-side sheet has an average basis weight at 80% elongation that is 1.0 to 1.3 times that of the smaller, and the larger of the average fiber diameters of the constituent fibers of the skin-side sheet and the non-skin-side sheet is 1.0 to 1.5 times that of the smaller.

This invention makes it possible to provide an absorbent article that improves comfort while minimizing the gap between the feel of the sheet on the non-skin side and the comfort of the sheet on the skin side.

FIG. 1 is a bottom view showing an example of the configuration of a disposable diaper according to an embodiment. FIG. 2 is a cross-sectional view taken along the line CW-CW in FIG. FIG. 3 is an end view showing an example of the configuration of the ventral waistline portion according to the embodiment. FIG. 4 is an end view showing an example of the configuration of the back waist portion according to the embodiment. FIG. 5 is a schematic diagram showing an example of the configuration of an ultrasonic bonding area according to an embodiment. FIG. 6 is a schematic diagram showing an example of a pattern of welded portions in an ultrasonic bonding region according to an embodiment.

The present disclosure relates to the following aspects:
[Aspect 1]
An absorbent article having a waist portion that covers the waist of a wearer and has a longitudinal direction, width direction, and thickness direction that are perpendicular to one another in an unfolded state, and comprising: a waist portion that covers the waist of a wearer; and an absorbent main body that covers the crotch area and includes an absorbent body, wherein the waist portion includes a stretchable sheet that extends in the width direction and is stretchable in the width direction; and a non-stretchable adjacent sheet that is adjacent to at least one of the skin side and non-skin side of the stretchable sheet and is non-stretchable; and one of the sheets is one of the non-stretchable adjacent sheet and the stretchable sheet, the other of the skin side sheet and the non-skin side sheet is the non-stretchable adjacent sheet, the skin side sheet and the non-skin side sheet are nonwoven fabrics, the larger of the skin side sheet and the non-skin side sheet has an average basis weight at 80% elongation that is 1.0 to 1.3 times that of the smaller one, and the larger of the average fiber diameters of the constituent fibers of the skin side sheet and the non-skin side sheet has an average fiber diameter that is 1.0 to 1.5 times that of the smaller one.

In this absorbent article, the waistband portion includes a stretchable sheet that extends widthwise and stretches widthwise, thereby improving comfort, such as flexibility, compared to an absorbent article that does not use a stretchable sheet. Furthermore, in this absorbent article, the skin-side sheet that makes up the skin-side side of the waistband portion and the non-skin-side sheet that makes up the non-skin-side side (both nonwoven fabrics) have roughly the same average basis weight and average fiber diameter of the constituent fibers at 80% elongation. In other words, the skin-side and non-skin-side sides of the waistband portion can be made roughly the same. This reduces the gap between the predicted comfort based on the feel of the non-skin-side sheet and the actual comfort, making the wearer less likely to feel uncomfortable. Therefore, an absorbent article can be provided that improves comfort while minimizing the gap between the feel of the non-skin-side sheet and the comfort of the skin-side sheet.

[Aspect 2]
The absorbent article of Aspect 1, wherein the skin-side sheet and the non-skin-side sheet are separate sheets, the skin-side sheet and the non-skin-side sheet are the non-stretchable adjacent sheet, the stretchable sheet is disposed between the skin-side sheet and the non-skin-side sheet, the stretchable sheet is a stretchable nonwoven fabric, and the average basis weight of the stretchable sheet and the non-stretchable adjacent sheet at 80% elongation, whichever is larger, is 1.0 to 1.3 times that of the smaller one.

The feel and comfort of an absorbent article can also be affected by the configuration of the stretchable sheet interposed between the skin-side sheet and the non-skin-side sheet, for example, by its average basis weight. Therefore, in this absorbent article, not only the skin-side sheet and non-skin-side sheet (non-stretch adjacent sheet), but also the stretchable sheet are nonwoven fabrics, and their average basis weights at 80% elongation are roughly the same. This makes it less likely that a gap will arise between the feel resulting from the non-skin-side sheet, including the stretchable sheet, and the comfort resulting from the skin-side sheet, including the stretchable sheet. Furthermore, a low average basis weight reduces the rigidity of the entire waistband, allowing the waistband to have supple flexibility. This improves the garment's conformability and feel against the skin, further improving the feel and comfort.

In addition, in this absorbent article, the skin-side sheet and non-skin-side sheet are separate sheets. This reduces the effect of the non-skin-side sheet on the movement of the skin-side sheet in response to the user's movements, while improving the skin-side sheet's ability to follow the user's movements. This further improves the comfort of wearing the absorbent article. In addition, in this absorbent article, the non-stretch sheets are located on both the skin-side and non-skin-side sides, sandwiching the stretch sheet, so that contraction of the stretch sheet creates unevenness in each non-stretch sheet. In other words, unevenness is created on the surface of the waistband. This unevenness imparts flexibility to the waistband that the wearer feels is fluffy. This further improves the comfort of wearing the absorbent article.

[Aspect 3]
the elastic sheet is an elastic nonwoven fabric, the elastic sheet and the non-elastic adjacent sheet are joined by a plurality of welds formed by ultrasonic welding, the waist portion has an adhesive-free area extending along the width direction in the center of the longitudinal direction, joined by the plurality of welds, and no adhesive is applied, and in either the back waist portion covering the waist on the back side of the wearer or the abdominal waist portion covering the waist on the abdominal side of the wearer, a band-shaped portion of the adhesive-free area 25 mm or more at the upper end in the longitudinal direction is composed only of the elastic sheet and the non-elastic adjacent sheet.

In this absorbent article, the stretchable sheet and the non-stretchable adjacent sheet are joined at multiple welds formed by ultrasonic welding, making it possible to make each joint smaller. This allows for more precise wrinkles to be formed in the waistband area by the stretchable sheet. Furthermore, because the article is not joined with an adhesive, there is no hardness when the adhesive hardens. This improves the flexibility of the entire waistband area, and the article feels supple when picked up or worn, further improving the feel and comfort of the garment.

In addition, in this absorbent article, as described above, the stretchable sheet and the non-stretchable adjacent sheet are joined at multiple welds, and therefore the waistband portion is joined at multiple welds, but has an adhesive-free area where no adhesive is applied. The presence of such a large adhesive-free area reduces the rigidity of the waistband portion and improves its flexibility. Therefore, the article feels soft when picked up or worn, further improving the feel and comfort.

Furthermore, in this absorbent article, a strip-shaped portion of 25 mm or more (extending along the width) at the upper longitudinal end of the non-adhesive region of either the dorsal waistband or the ventral waistband is composed only of a stretchable sheet and a non-stretchable adjacent sheet. This strip-shaped portion abuts the iliac crest, a protruding part of the wearer's waist, or its vicinity, and is an area that strongly influences comfort. Because this strip-shaped portion of either the dorsal waistband or the ventral waistband is composed only of a non-adhesive region and a stretchable sheet and a non-stretchable adjacent sheet, the wearer can feel a greater softness and suppleness when wearing the article, thereby further improving the feel and comfort.

[Aspect 4]
An absorbent article as described in aspect 3, wherein in both the back waist portion and the ventral waist portion, a strip-shaped portion of 25 mm or more at the upper end of the longitudinal direction of the non-adhesive-applied area is composed only of the stretchable sheet and the non-stretchable adjacent sheet.

In this absorbent article, both the back waistband and the ventral waistband have a strip-shaped section of at least 25 mm at the upper longitudinal end of the non-adhesive area, which is composed only of a stretchable sheet and a non-stretchable adjacent sheet. This strip-shaped section abuts the iliac crest, a protruding part of the wearer's waist, or its vicinity, and is an area that has a significant impact on comfort. Because the strip-shaped sections of both the back waistband and the ventral waistband are non-adhesive and composed only of a stretchable sheet and a non-stretchable adjacent sheet, the wearer can feel an even greater softness and suppleness when wearing the article, thereby further improving the feel and comfort.

[Aspect 5]
Aspect 5. The absorbent article according to any one of aspects 1 to 4, wherein the average fiber diameter of the constituent fibers constituting the nonwoven fabric is 5.0 to 17 μm, and the average basis weight of the nonwoven fabric at 80% elongation is 9 to 19 g/ ^m2 .

In this absorbent article, the average fiber diameter of the constituent fibers making up the nonwoven fabric is relatively small (5.0 to 17 μm), and the average basis weight at 80% elongation is low (9 to 19 g/m ² ). This reduces the rigidity of the entire waistband portion, allowing the waistband portion to have supple flexibility. This improves the fabric's conformability and feel against the skin, further improving the feel and comfort of the garment.

[Aspect 6]
The absorbent article of claim 1, wherein the stretchable sheet includes a non-stretchable first sheet positioned on the skin side and non-skin side, and a stretchable second sheet positioned between the first sheet on the skin side and non-skin side.

In this absorbent article, a non-stretchable first sheet is present on both the skin-facing and non-skin-facing sides of the stretchable sheet, sandwiching a stretchable second sheet between them. Therefore, as the second sheet contracts, unevenness is formed on each first sheet. In other words, unevenness is created on the surface of the stretchable sheet. These unevenness imparts flexibility to the waist area, giving the wearer a fluffy feel. This further improves the comfort of wearing the absorbent article.

[Aspect 7]
Aspect 7. The absorbent article according to any one of Aspects 1 to 6, wherein the average fiber diameter of the constituent fibers constituting the nonwoven fabric of the skin side sheet and the non-skin side sheet is 5.0 to 17 μm.

In this absorbent article, the constituent fibers of the nonwoven fabric that makes up the skin-side sheet and non-skin-side sheet have a small average fiber diameter (5.0 to 17 μm). This reduces the bending rigidity of the nonwoven fabric, resulting in greater flexibility throughout the waist area. This makes the waist area softer, further improving the feel and comfort of the garment.

[Aspect 8]
Aspect 8. The absorbent article according to any one of aspects 1 to 7, wherein the nonwoven fabric of the skin side sheet and the non-skin side sheet has an average basis weight of 9 to 19 g/ ^m2 at 80% elongation.

In this absorbent article, the nonwoven fabric constituting the skin-side sheet and non-skin-side sheet has a small average basis weight (9 to 19 g/m ² ) at 80% elongation. This reduces the bending rigidity of the nonwoven fabric, thereby increasing the flexibility of the entire waistband portion. This makes the waistband portion softer, further improving the feel and comfort of the garment.

[Aspect 9]
The absorbent article according to any one of Aspects 1 to 8, wherein constituent fibers of the nonwoven fabric of the skin side sheet and the non-skin side sheet are long fibers only.

In this absorbent article, the nonwoven fabric that makes up the skin-side sheet and non-skin-side sheet is made entirely of long fibers. This increases the flexibility of the nonwoven fabric, which in turn increases the flexibility of the entire waistband section. This makes the waistband section softer, further improving the feel and comfort of the garment.

[Aspect 10]
Aspect 10. The absorbent article according to any one of Aspects 1 to 9, wherein constituent fibers of the nonwoven fabric of the skin side sheet and the non-skin side sheet include fibers containing a copolymer blend.

In this absorbent article, the constituent fibers of the nonwoven fabric that makes up the skin-side sheet and non-skin-side sheet contain copolymer-blended fibers. This improves the softness, particularly the suppleness, of the nonwoven fabric, further improving the suppleness of the entire waistband area. This makes the waistband area more supple, further improving the feel and comfort of the garment.

[Aspect 11]
Aspect 11. The absorbent article according to any one of Aspects 1 to 10, wherein the nonwoven fabrics of the skin side sheet and the non-skin side sheet contain a lubricant.

In this absorbent article, the nonwoven fabric that makes up the skin-side sheet and non-skin-side sheet contains a lubricant (softener). This increases the slipperiness of the nonwoven fabric surface, reducing friction around the waist. This makes the waist area feel smooth against the skin, reducing damage caused by friction on the skin surface when worn. This further improves the feel and comfort of the garment.

[Aspect 12]
Aspect 12. The absorbent article according to any one of Aspects 1 to 11, wherein constituent fibers of the nonwoven fabric of the skin side sheet and the non-skin side sheet include recycled fibers.

In this absorbent article, the constituent fibers of the nonwoven fabric that makes up the skin-side sheet and non-skin-side sheet contain recycled fibers (e.g., rayon). This improves the suppleness and smoothness of the nonwoven fabric, improving the feel against the skin around the waist. This improves the fit around the skin around the waist, reducing skin problems such as rashes caused by friction. This further improves the feel and comfort of the garment.

[Aspect 13]
Aspect 13. The absorbent article according to any one of Aspects 1 to 12, wherein the skin side sheet and the non-skin side sheet are made of nonwoven fabric, and constituent fibers of the nonwoven fabric include cotton.

In this absorbent article, the constituent fibers of the nonwoven fabric that makes up the skin-side sheet and non-skin-side sheet contain cotton. Compared to synthetic fibers, cotton has rounded fiber tips that do not irritate the skin. In other words, cotton has almost no rough or prickly feel to the touch, and does not cause any discomfort when worn, further improving the feel and comfort of wearing the garment.

The absorbent article according to the embodiment will be described below using an example of an adult pants-type disposable diaper (hereinafter simply referred to as a "disposable diaper"). However, the type of absorbent article is not limited to this example, and other types of absorbent articles may be used as long as they do not deviate from the scope of the present invention. Examples of such absorbent articles include children's pants-type disposable diapers and shorts-type napkins.

An absorbent article according to an embodiment will now be described. Figures 1 to 4 are diagrams showing an example configuration of a disposable diaper 1 according to an embodiment. Figure 1 is a bottom view of the example configuration of a disposable diaper 1 according to an embodiment in an unfolded state, and is therefore a view from the non-skin side. Figure 2 is a schematic cross-sectional view taken along line CW-CW in Figure 1. Figure 3 is an end view of the example configuration of a ventral waistline section according to an embodiment in an unfolded state. Figure 4 is an end view of the example configuration of a dorsal waistline section according to an embodiment in an unfolded state.

In the unfolded state shown in Figure 1, the disposable diaper 1 has a longitudinal direction L, a width direction W, and a thickness direction T that are perpendicular to each other. It has a longitudinal centerline CL that passes through the center of the width direction W and extends parallel to the longitudinal direction L, and a widthwise centerline CW that passes through the center of the longitudinal direction L and extends parallel to the width direction W. The directions and sides approaching the longitudinal centerline CL are referred to as the inward and inner sides of the width direction W, respectively, and the directions and sides moving away from the longitudinal centerline CW are referred to as the outward and outer sides of the width direction W, respectively. Meanwhile, the directions and sides approaching the widthwise centerline CW are referred to as the inward and inner sides of the longitudinal direction L, respectively, and the directions and sides moving away from the widthwise centerline CW are referred to as the outward and outer sides of the longitudinal direction L, respectively. The side of the longitudinal direction L toward the edge of the disposable diaper 1 corresponding to the wearer's abdomen (the abdominal edge) is also referred to as the front side of the longitudinal direction L, and the side toward the edge of the disposable diaper 1 corresponding to the wearer's back (the back edge) is also referred to as the rear side of the longitudinal direction L. Furthermore, "plan view" refers to the disposable diaper 1 in an unfolded state on a plane including the longitudinal direction L and the width direction W, viewed from above in the thickness direction T, and "planar shape" refers to the shape as perceived in a planar view. "Planar direction" refers to any direction parallel to a plane including the width direction W and the longitudinal direction L. "Skin side" and "non-skin side" refer to the side relatively closer to and farther from the wearer's skin surface in the thickness direction T when the disposable diaper 1 is worn by a wearer. "A direction along the longitudinal direction L" is not limited to being parallel to the longitudinal direction L, but also includes a range of ±30° with respect to the longitudinal direction L. "A direction along the width direction W" is not limited to being parallel to the width direction W, but also includes a range of ±30° with respect to the width direction W. These definitions are used not only for the disposable diaper 1 in an unfolded state, but also for the disposable diaper 1 in a normal state and the components of the disposable diaper 1.

However, the "unfolded state" of a disposable diaper refers to a state in which the widthwise ends that define the boundary between the ventral waistband and the back waistband of the disposable diaper are released, and the disposable diaper is unfolded on a flat surface until the non-stretchable sheet (e.g., nonwoven fabric) that constitutes the ventral waistband and back waistband is wrinkle-free without tearing. If the disposable diaper includes a stretchable sheet or elastic member, the stretchable sheet or elastic member is stretched until the non-stretchable sheet is wrinkle-free. The ventral waistband, back waistband, the joining of the widthwise ends, the stretchable sheet or elastic member, and the non-stretchable sheet material (e.g., nonwoven fabric) are described below.

As shown in FIG. 1, the disposable diaper 1 comprises a ventral waistband portion (ventral waist belt) 2 located at the front in the longitudinal direction L, a dorsal waistband portion (dorsal waist belt) 3 located at the rear, and an absorbent main body 10 located between the ventral waistband portion 2 and the dorsal waistband portion 3. In this embodiment, the ventral waistband portion 2 has a generally rectangular shape extending in the width direction W, and in this embodiment, the rear portion in the longitudinal direction L and the center portion in the width direction W has a generally trapezoidal shape extending toward the rear. The dorsal waistband portion 3 has a generally rectangular shape extending in the width direction W, and in this embodiment, the front portion in the longitudinal direction L has a generally trapezoidal shape extending toward the front. The absorbent main body 10 has a generally rectangular shape extending in the longitudinal direction L.

The ventral waist portion 2 covers the wearer's abdomen. The back waist portion 3 covers the wearer's buttocks or back. The absorbent body 10 covers the wearer's crotch (excretory opening) and includes an absorber 11. One end of the absorbent body 10 in the longitudinal direction L is layered and joined to the skin-side surface of the ventral waist portion 2 at the center in the width direction W, and the other end is layered and joined to the skin-side surface of the back waist portion 3 at the center in the width direction W. A pair of fastening portions 2a, 2a at both ends in the width direction W of the ventral waist portion 2 and a pair of fastening portions 3a, 3a at both ends in the width direction W of the back waist portion 3 overlap in the thickness direction T and are joined along the longitudinal direction L to form the disposable diaper 1. In this case, the joined ventral waist portion 2 and back waist portion 3 form a waist portion (waist belt) that covers the wearer's waist. Additionally, a waist opening through which the wearer's waist passes is defined by the outer end of the ventral waist portion 2 in the longitudinal direction L and the outer end of the dorsal waist portion 3 in the longitudinal direction L. Furthermore, a pair of leg openings through which the wearer's legs pass is defined by both ends of the absorbent main body 10 in the width direction W, the inner end of the ventral waist portion 2 in the longitudinal direction L, and the inner end of the dorsal waist portion 3 in the longitudinal direction L.

In this embodiment, in the state shown in FIG. 1, the ventral waist portion 2 and the back waist portion 3 are spaced apart from each other in the longitudinal direction L. That is, the ventral waist portion 2 and the back waist portion 3 are formed separately from each other. In another embodiment, the disposable diaper 1 further includes a crotch portion located between the ventral waist portion 2 and the back waist portion 3, with one end connected to the ventral waist portion 2 and the other end connected to the back waist portion 3. In this case, the ventral waist portion 2, the back waist portion 3, and the crotch portion may be formed integrally or separately.

In this embodiment, the ventral waist portion 2 comprises a liquid-impermeable first outer sheet 22 and a second outer sheet 23. The first outer sheet 22 is positioned on the skin side, and the second outer sheet 23 is positioned on the non-skin side. The first outer sheet 22 and the second outer sheet 23 are laminated in the thickness direction T and joined to each other by thermal welding using ultrasonic bonding. However, the first outer sheet 22 and the second outer sheet 23 may also be joined by other methods of thermal welding or adhesive. The ventral waist portion 2 does not need to have the non-skin side second outer sheet 23. In that case, the ventral stretchable sheet 21, described below, is positioned on the non-skin side of the ventral waist portion 2. While a portion of the first outer sheet 22 may be folded back toward the second outer sheet 23, or a portion of the second outer sheet 23 may be folded back toward the first outer sheet 22, it is preferable that the first outer sheet 22 and the second outer sheet 23 are separate entities. In other words, it is preferable not to fold a single sheet and use it as the first exterior sheet 22 and the second exterior sheet 23.

Similarly, in this embodiment, the back waist portion 3 includes a liquid-impermeable first outer sheet 32 and a second outer sheet 33. The first outer sheet 32 is positioned on the skin side, and the second outer sheet 33 is positioned on the non-skin side. The first outer sheet 32 and the second outer sheet 33 are laminated in the thickness direction T and joined to each other by thermal welding using ultrasonic bonding. However, the first outer sheet 32 and the second outer sheet 33 may also be joined by other methods of thermal welding or adhesive. The back waist portion 3 does not need to have the non-skin side second outer sheet 33. In that case, the back stretchable sheet 31, described below, is positioned on the non-skin side of the back waist portion 3. While a portion of the first outer sheet 32 may be folded back toward the second outer sheet 33, or a portion of the second outer sheet 33 may be folded back toward the first outer sheet 32, it is preferable that the first outer sheet 32 and the second outer sheet 33 are separate entities. In other words, it is preferable not to fold a single sheet and use it as the first exterior sheet 32 and the second exterior sheet 33.

Each of the above exterior sheets is a non-stretchable sheet, and examples of the material include liquid-impermeable nonwoven fabric. The average fiber diameter of the constituent fibers making up the nonwoven fabric is, for example, 5.0 to 18 μm, preferably 5.0 to 17 μm, and more preferably 8 to 17 μm. The average basis weight of the nonwoven fabric (sheet) at 80% elongation is, for example, 5 to 19 g/ ^m2 , preferably 9 to 19 g/ ^m2 , and more preferably 11 to 19 g/ ^m2 . The "80% elongation" state will be described later.

In this embodiment, the ventral waistline portion 2 includes a ventral stretchable sheet 21, which is a stretchable sheet for waist gathering, between the first outer sheet 22 and the second outer sheet 23. The ventral stretchable sheet 21 is stretchable in the width direction W. The ventral stretchable sheet 21 is 80% of the size of the first outer sheet 22, preferably 90% or more, and more preferably 95% or more. In this embodiment, the ventral stretchable sheet 21 has substantially the same size (shape) as the first outer sheet 22 in a plan view. The ventral stretchable sheet 21 is joined in an elongated state to the first outer sheet 22 and the second outer sheet 23 by adhesive or heat welding (ultrasonic bonding, etc.). In this embodiment, the ventral stretchable sheet 21 is joined in an elongated state to the first outer sheet 22 and the second outer sheet 23 by heat welding using ultrasonic bonding. Note that the ventral stretchable sheet 21 may not be present in the region of the ventral waistline portion 2 that is located on the non-skin side of the absorbent main body 10.

Similarly, in this embodiment, the back waistband portion 3 includes a back stretchable sheet 31, which is a stretchable sheet for waist gathering, between the first outer sheet 32 and the second outer sheet 33. The back stretchable sheet 31 is stretchable in the width direction W. The back stretchable sheet 31 is 80% of the size of the first outer sheet 22, preferably 90% or more, and more preferably 95% or more. In this embodiment, the back stretchable sheet 31 has substantially the same size (shape) as the first outer sheet 32 in a plan view. The back stretchable sheet 31 is joined in a stretched state to the first outer sheet 32 and the second outer sheet 33 by adhesive or heat welding (ultrasonic bonding, etc.). In this embodiment, the back stretchable sheet 31 is joined in a stretched state to the first outer sheet 32 and the second outer sheet 33 by heat welding using ultrasonic bonding. The back-side stretchable sheet 31 does not need to be present in the area of the back-side waistband portion 3 that is located on the non-skin side of the absorbent body 10.

The materials for the ventral stretchable sheet 21 and the dorsal stretchable sheet 31 are not particularly limited as long as they are stretchable in the width direction W. Examples include the stretchable nonwoven fabric described in Patent Document 2. Such stretchable nonwoven fabrics are formed by stretching a specified nonwoven fabric sheet. The specified nonwoven fabric sheet is a potentially stretchable nonwoven fabric containing a mixture of stretchable and stretchable fibers, in which the stretchable and stretchable fibers are fixed together by self-fusion through softening or melting at numerous fused joints spaced at regular intervals. Stretchable fibers include, for example, fibers that undergo plastic deformation at elongations smaller than the maximum strength of the stretchable fibers. For example, stretchable fibers are fibers that are inelastically stretchable, and stretchable fibers are fibers that are elastically stretchable. The average fiber diameter and average basis weight of the constituent fibers in the stretchable nonwoven fabric can be adjusted to the desired values by changing the average fiber diameter and average basis weight of the extensible fibers and stretchable fibers in the specified nonwoven fabric sheet, as well as the conditions for stretching.

Examples of extensible fibers include extensible thermoplastic polyolefin fibers. Examples of polyolefin fibers include monofilaments such as polypropylene fibers and polyethylene fibers, and core-sheath composite fibers made of polypropylene or polyethylene. Examples of stretchable fibers include extensible thermoplastic elastomer fibers. Examples of elastomer fibers include urethane-based elastomers, polystyrene-based elastomers, polyolefin-based elastomers, polyamide-based elastomers, and polyester-based elastomers, specifically polyurethane-based elastomers.

The average basis weight of a stretchable nonwoven fabric when relaxed is, for example, 15 to 50 g/ ^m2 , but when stretched, for example, at 80% stretch, the average basis weight drops to about 60% of the relaxed basis weight. Therefore, the average basis weight when stretched to 80% is, for example, 8 to 28 g/ ^m2 , and preferably 9 to 17 g/ ^m2 . The average fiber diameter of the polyolefin fiber in the stretchable fiber is, for example, 5 to 21 μm, and preferably 5.0 to 17 μm. It is also preferable that the elastomeric fiber in the stretchable fiber has a diameter similar to that of the stretchable fiber.

In this embodiment, the ventral waist portion 2 further comprises a plurality of waist elastic members 25 extending along the width direction W and spaced apart in the longitudinal direction L, located between the first outer sheet 22 and the second outer sheet 23 and near the waist opening (at the outer end in the longitudinal direction L). Similarly, in this embodiment, the back waist portion 3 further comprises a plurality of waist elastic members 35 extending along the width direction W and spaced apart in the longitudinal direction L, located between the first outer sheet 32 and the second outer sheet 33 and near the waist opening (at the outer end in the longitudinal direction L).

In this embodiment, the ventral waistline portion 2 further includes a plurality of leg elastic members 26 for leg gathers between the first outer sheet 22 and the second outer sheet 23. The leg elastic members 26 are arranged at intervals along the inner edge of the ventral waistline portion 2 in the longitudinal direction L so as to convex toward the back waistline portion 3 in a plan view. Note that the leg elastic members 26 are not arranged in the area overlapping with the absorbent body 11 in the thickness direction T, but may be arranged there. Similarly, in this embodiment, the back waistline portion 3 further includes a plurality of leg elastic members 36 for leg gathers between the first outer sheet 32 and the second outer sheet 33. The leg elastic members 36 are arranged at intervals along the inner edge of the back waistline portion 3 in the longitudinal direction L so as to convex toward the ventral waistline portion 2 in a plan view. Note that the leg elastic members 36 are also arranged in the area overlapping with the absorbent body 11 in the thickness direction T, but may not be arranged there.

The waist elastic member 25, leg elastic member 26, waist elastic member 35, and leg elastic member 26 may be made of, for example, rubber thread. They are joined to each sheet by adhesive or heat welding (ultrasonic bonding, etc.). In this embodiment, adhesive is used.

In this embodiment, the absorbent body 10 includes a liquid-permeable top sheet 12, a liquid-impermeable back sheet 13, and an absorbent body 11 located between the top sheet 12 and the back sheet 13 and absorbing and retaining liquid. Examples of materials for the top sheet 12 include liquid-permeable nonwoven fabrics or woven fabrics, synthetic resin films with liquid-permeable holes formed therein, and combinations of the same or different materials. Examples of materials for the back sheet 13 include liquid-impermeable but breathable nonwoven fabrics, synthetic resin films with air holes formed therein, and combinations of the same or different materials. A liquid-permeable diffusion sheet may also be provided between the top sheet 12 and the absorbent body 11, diffusing liquid in the planar direction.

Examples of the top sheet 12 include a flat sheet with no irregularities, a sheet extending in the longitudinal direction L and having multiple convex portions spaced apart in the width direction W and multiple concave portions provided between each of the multiple convex portions, and a sheet with multiple convex portions that are approximately circular in plan view and arranged in a checkerboard pattern in plan view.

The type of liquid-permeable or liquid-impermeable nonwoven fabric (including the first outer sheet 22, the second outer sheet 23, the first outer sheet 32, and the second outer sheet 33) is not particularly limited as long as it can be used in absorbent articles. Examples of nonwoven fabrics include meltblown nonwoven fabrics, spunbond nonwoven fabrics, airlaid nonwoven fabrics, spunlace nonwoven fabrics, air-through nonwoven fabrics, and combinations thereof. The material of the nonwoven fabric is not particularly limited as long as it can be used in absorbent articles, and examples include synthetic resin fibers and pulp fibers. The synthetic resin is not particularly limited as long as it can be used in absorbent articles, and examples include olefin-based resins such as polyethylene and polypropylene, polyamide-based resins such as 6-nylon and 6,6-nylon, and polyester-based resins such as polyethylene terephthalate and polybutylene terephthalate. Pulp fibers are described below. The type of liquid-permeable or liquid-impermeable synthetic resin film is not particularly limited as long as it can be used in absorbent articles, and examples include known film materials. There are no particular restrictions on the material for the synthetic resin film, as long as it can be used for absorbent articles, and examples include the synthetic resins mentioned above.

The absorbent body 11 includes an absorbent core 11a that absorbs and retains liquid, and a core wrap sheet 11b that encases the absorbent core 11a. Materials for the absorbent core 11a include absorbent materials such as pulp fibers and superabsorbent polymers. Examples of pulp fibers include cellulosic fibers. Examples of cellulosic fibers include wood pulp, crosslinked pulp, non-wood pulp, regenerated cellulose, and semi-synthetic cellulose. Examples of superabsorbent polymers (SAPs) include polyacrylate-based, polysulfonate-based, and maleic anhydride-based water-absorbing polymers. Examples of materials for the core wrap sheet 11b include liquid-permeable nonwoven fabrics (including tissues) made of synthetic resin fibers or pulp fibers, and composite sheets of these. There are no particular restrictions on the type of synthetic resin fiber, as long as it can be used in absorbent articles, and examples include known synthetic fibers. The types of nonwoven fabric, synthetic resin, and pulp fiber are as described above. In Figure 2, the seam of the core wrap sheet 11b is located on the skin side, but this is not limited to this example and may be located on the non-skin side or on the side.

The absorbent body 11 and the topsheet 12, and the absorbent body 11 and the backsheet 13 are each bonded to each other with an adhesive. The topsheet 12 and the backsheet 13 are bonded to each other at their peripheral edges with an adhesive. Examples of adhesives include hot melt adhesive. The shape of the absorbent body 10 is not limited to the above example, as long as it is long in the longitudinal direction L, and examples include a rectangle with rounded corners, a rectangle with short sides that curve convexly outward, and an hourglass shape.

The basis weights of the topsheet 12, backsheet 13, and absorbent body 11 are adjusted appropriately depending on the absorption performance required of the disposable diaper 1, but are not particularly limited as long as they can be used as sheets for the disposable diaper 1. The basis weight of the topsheet 12 is, for example, 5 to 200 g/ ^m2 . The basis weight of the backsheet 13 is, for example, 5 to 200 g/ ^m2 . The basis weight of the absorbent core 11a is, for example, 10 to 2000 g/ ^m2 . The basis weight of the core wrap sheet 11b is, for example, 5 to 100 g/ ^m2 .

In this embodiment, the absorbent body 10 further includes a lower sheet 14 laminated on the non-skin side of the backsheet 13. Both sides of the lower sheet 14 in the width direction W wrap around from both ends of the laminate of the topsheet 12, absorber 11, and backsheet 13 in the width direction W to the skin side, forming a pair of leakage barrier walls 15 extending in the longitudinal direction L. Each leakage barrier wall 15 has its outer edge in the width direction W fixed to the edge of the absorbent body 10 in the width direction W, and its inner edge in the width direction W left unfixed. Both ends of the leakage barrier walls 15 in the longitudinal direction L are covered and fixed by cover sheets 24 (described below) and 34 (described below). Examples of materials for the lower sheet 14 and leakage barrier walls 15 include hydrophobic sheets such as hydrophobic nonwoven fabrics. In another embodiment, examples of materials for the lower sheet 14 and leakage barrier walls 15 include hydrophilic sheets such as hydrophilic nonwoven fabrics. Each leak-preventing wall 15 includes two leak-preventing elastic members 16 extending along the longitudinal direction L at its inner end in the width direction W. The leak-preventing elastic members 16 are exemplified by rubber threads. In another embodiment, each of the pair of leak-preventing walls 15 has its inner end in the width direction W folded back further outward in the width direction W. In another embodiment, the number of leak-preventing elastic members 16 is one, or three or more.

The cover sheet 24 is laminated to the first outer sheet 22 so as to cover the front end of the absorbent body 10 in the longitudinal direction L from the skin side. Similarly, the cover sheet 34 is laminated to the second outer sheet 32 so as to cover the rear end of the absorbent body 10 in the longitudinal direction L from the skin side. They are joined to each other by adhesive or heat welding (ultrasonic bonding, etc.). In this embodiment, heat welding is used.

In the disposable diaper 1 described above, the waist portion, for example, the ventral waist portion 2, includes a ventral-side stretchable sheet 21 (stretchable sheet) and at least one of a first outer sheet 22 (non-stretchable adjacent sheet) adjacent to the skin side of the ventral-side stretchable sheet 21 and a second outer sheet 23 (non-stretchable adjacent sheet) adjacent to the non-skin side. Of the ventral-side stretchable sheet 21, first outer sheet 22, and second outer sheet 23, the sheet closest to the skin side is referred to as the skin-side sheet, and the sheet closest to the skin side is referred to as the non-skin-side sheet. In this embodiment, the first outer sheet 22 is the skin-side sheet, and the second outer sheet 23 is the non-skin-side sheet. If the second outer sheet 23 is not provided, the ventral-side stretchable sheet 21 is the non-skin-side sheet. If the first outer sheet 22 is not provided, the ventral-side stretchable sheet 21 is the skin-side sheet.

Similarly, the back-side waistband portion 3 includes a back-side stretchable sheet 31 (stretchable sheet) and at least one of a first outer sheet 32 (non-stretchable adjacent sheet) adjacent to the skin side of the back-side stretchable sheet 31 and a second outer sheet 33 (non-stretchable adjacent sheet) adjacent to the non-skin side. Of the back-side stretchable sheet 31, first outer sheet 32, and second outer sheet 33, the sheet closest to the skin side is referred to as the skin-side sheet, and the sheet closest to the skin side is referred to as the non-skin-side sheet. In this embodiment, the first outer sheet 32 is the skin-side sheet, and the second outer sheet 33 is the non-skin-side sheet. If the second outer sheet 33 is not provided, the back-side stretchable sheet 31 is the non-skin-side sheet. If the first outer sheet 32 is not provided, the back-side stretchable sheet 31 is the skin-side sheet.

In the disposable diaper 1 described above, the average basis weight of one of the skin-side sheet and the non-skin-side sheet at 80% elongation is 1.0 to 1.3 times the average basis weight of the other at 80% elongation. In other words, the larger of the average basis weights of the skin-side sheet and the non-skin-side sheet at 80% elongation is 1.0 to 1.3 times that of the smaller. Preferably, the larger is 1.0 to 1.05 times that of the smaller. In this embodiment, the average basis weight of one of the first outer sheet 22 and the second outer sheet 23 at 80% elongation is 1.0 to 1.3 times the average basis weight of the other at 80% elongation. Therefore, the larger of the average basis weights of the first outer sheet 22 and the second outer sheet 23 at 80% elongation is 1.0 to 1.3 times that of the smaller. Furthermore, the average basis weight of one of the first and second outer sheets 32 and 33 at 80% elongation is 1.0 to 1.3 times the average basis weight of the other at 80% elongation. Therefore, the larger of the first and second outer sheets 32 and 33 at 80% elongation has an average basis weight 1.0 to 1.3 times that of the smaller. In both cases, the larger is preferably 1.0 to 1.05 times that of the smaller. Therefore, the skin-side sheet and non-skin-side sheet have approximately the same average basis weight at 80% elongation.

However, the "80% stretch" state is as follows: First, the "0% stretch" state refers to the natural state of the disposable diaper 1 product. In other words, it refers to a state in which the stretchable sheets, i.e., the ventral stretchable sheet 21 and the dorsal stretchable sheet 31, are relaxed. On the other hand, the "100% stretch" state refers to a state in which the non-stretchable adjacent sheets of the disposable diaper 1, i.e., the first outer sheet 22 and the second outer sheet 23 and the first outer sheet 32 and the second outer sheet 33, are spread out on a flat surface until they are wrinkle-free without breaking. Therefore, the "80% stretch" state refers to a stretched state that is 80% of the "100% stretch" state, with the "0% stretch" state as the reference. However, because the state in which the user stretches the disposable diaper 1 to check the degree of stretch in the width direction W before putting it on, and the state in which the disposable diaper 1 stretches in the width direction W when put on is approximately 80%, the 80% stretch state is used as a guideline.

In the disposable diaper 1 described above, the average fiber diameter of the constituent fibers of one of the skin-side sheet and the non-skin-side sheet is 1.0 to 1.5 times the average fiber diameter of the constituent fibers of the other. In other words, the larger of the average fiber diameters of the constituent fibers of the skin-side sheet and the non-skin-side sheet is 1.0 to 1.5 times the smaller. Preferably, the larger is 1.0 to 1.1 times the smaller. In this embodiment, the average fiber diameter of the constituent fibers of one of the first outer sheet 22 and the second outer sheet 23 is 1.0 to 1.5 times the average fiber diameter of the constituent fibers of the other. Therefore, the larger of the average fiber diameters of the constituent fibers of the first outer sheet 22 and the second outer sheet 23 is 1.0 to 1.5 times the smaller. Furthermore, the average fiber diameter of the constituent fibers of one of the first and second outer sheets 32 and 33 is 1.0 to 1.5 times the average fiber diameter of the constituent fibers of the other. Therefore, the larger average fiber diameter of the constituent fibers of the first and second outer sheets 32 and 33 is 1.0 to 1.5 times the smaller average fiber diameter. Preferably, the larger average fiber diameter of each is 1.0 to 1.1 times the smaller average fiber diameter. Therefore, the skin-side sheet and non-skin-side sheet have roughly the same average fiber diameter of their constituent fibers.

As described above, in the disposable diaper 1, the waist portion (ventral waist portion 2 and back waist portion 3) includes elastic sheets (ventral elastic sheet 21 and back elastic sheet 31) that extend in the width direction W and stretch in the width direction W. This improves the wearer's comfort, such as flexibility, compared to a disposable diaper 1 that does not use elastic sheets. Furthermore, in the disposable diaper 1, the skin-side sheets (e.g., first outer sheets 22 and 32: nonwoven fabric) that make up the skin-side surfaces of the waist portion (ventral waist portion 2 and back waist portion 3) and the non-skin-side sheets (e.g., second outer sheets 23 and 33: nonwoven fabric) that make up the non-skin-side surfaces have approximately the same average basis weight and average fiber diameter of the constituent fibers at 80% elongation. In other words, the skin-side and non-skin-side surfaces of the waist portion (ventral waist portion 2 and back waist portion 3) can be made approximately the same. This reduces the gap between the expected wearing comfort based on the feel of the non-skin-side sheets (e.g., second outer sheets 23 and 33) and the actual wearing comfort, making it less likely for the wearer to feel uncomfortable. Therefore, it is possible to provide an absorbent article that improves wearing comfort while reducing the gap between the feel caused by the non-skin-side sheets and the wearing comfort caused by the skin-side sheets.

<Method for measuring average basis weight of sheet at 80% elongation>
(1) A disposable diaper is stretched 80% in the width direction, and a 60 mm x 60 mm sample is cut out from the waist area.
(2) The heat-sealed sheets are peeled off one by one from the cut-out sample, and the mass of each peeled sheet is measured using an electronic balance.
(3) For each sheet, divide the measured mass (g) by 0.06 m x 0.06 m to calculate the basis weight.
(4) The above steps (1) to (3) are carried out for four samples, and the average basis weight of each sheet is calculated to be the average basis weight of each sheet.

<Average fiber diameter of the constituent fibers of the sheet>
(1) A 10 mm x 10 mm rectangular sample piece is cut out from the sheet to be measured.
(2) Using a digital microscope VHX-7000 manufactured by Keyence Corporation, the surface of the sample piece is magnified and observed, and the number of fibers and fiber diameter (diameter) for each layer are determined by gradually increasing the focal depth from the lower layer to the upper layer within a 0.1 mm × 0.1 mm area.
(3) Calculate the average fiber diameter of the region from the number and diameter of the fibers in all layers.
(4) The above steps (1) to (3) are repeated several times (for example, 2 to 4 times), and the average value is taken as the final average fiber diameter (μm).

In a preferred aspect of this embodiment, the skin-side sheet and the non-skin-side sheet are separate sheets. In the example shown in Figures 1 to 4, for example, in the ventral waistband portion 2, the skin-side sheet and the non-skin-side sheet are the first outer sheet 22 and the second outer sheet 23, respectively, which are formed from separate sheets (e.g., nonwoven fabric). Similarly, in the dorsal waistband portion 3, the skin-side sheet and the non-skin-side sheet are the first outer sheet 32 and the second outer sheet 33, respectively, which are formed from separate sheets (e.g., nonwoven fabric). This reduces the effect of the non-skin-side sheets (second outer sheet 23, second outer sheet 33) on the user's movements, while improving the ability of the skin-side sheets (first outer sheet 22, first outer sheet 32) to follow the user's movements. This further improves the comfort of the disposable diaper 1. However, although the skin-side sheet and the non-skin-side sheet are separate sheets, it is preferable that they be the same type of sheet. That is, as mentioned above, it is preferable that the skin-side sheet and non-skin-side sheet have roughly the same average basis weight at 80% elongation, that the average fiber diameter of the constituent fibers be roughly the same, and that they be made of the same type of nonwoven fabric (for example, both sheets are spunbond nonwoven fabrics, etc.) from the perspective of minimizing the gap between feel and comfort.

In another embodiment, the stretchable sheets (ventral stretchable sheet 21 and back stretchable sheet 31) may include a non-stretchable first sheet positioned on the skin side and non-skin side, and a stretchable second sheet positioned between the skin side and non-skin side first sheets. That is, the stretchable sheets (ventral stretchable sheet 21 and back stretchable sheet 31) may be sheets in a form different from stretchable nonwoven fabric, in which the non-stretchable first sheet is positioned on the skin side and non-skin side, sandwiching the stretchable second sheet. In this case, contraction of the second sheet forms unevenness in each first sheet. That is, unevenness is created on the surface of the stretchable sheet. The unevenness can impart flexibility to the waist portion (ventral waist portion 2 and back waist portion 3) that feels fluffy to the wearer. This can further improve the comfort of wearing the disposable diaper 1.

In a preferred aspect of this embodiment, when the skin-side sheet and the non-skin-side sheet are made of nonwoven fabric, the average fiber diameter of the constituent fibers making up these nonwoven fabrics is 5.0 to 17 μm. Preferably, the average fiber diameter is 7.0 to 16 μm. For example, in the ventral waistband portion 2, when the skin-side sheet and the non-skin-side sheet are the first outer sheet 22 and the second outer sheet 23, respectively, and these are nonwoven fabrics, the average fiber diameter of the constituent fibers making up these nonwoven fabrics is 5.0 to 17 μm. Similarly, in the dorsal waistband portion 3, when the skin-side sheet and the non-skin-side sheet are the first outer sheet 32 and the second outer sheet 33, respectively, and these are nonwoven fabrics, the average fiber diameter of the constituent fibers making up these nonwoven fabrics is 5.0 to 17 μm. Preferably, the average fiber diameter is 7.0 to 16 μm in both cases. Furthermore, when either the skin-side sheet or the non-skin-side sheet is the ventral-side stretchable sheet 21 or the dorsal-side stretchable sheet 31, if they are stretchable nonwoven fabrics, the average fiber diameter of their constituent fibers is 5.0 to 17 μm.

As such, in the disposable diaper 1, the constituent fibers of the nonwoven fabric that makes up the skin-side sheet and non-skin-side sheet have a small average fiber diameter (5.0 to 17 μm). This reduces the bending rigidity of the nonwoven fabric, resulting in greater flexibility in the entire waistband portion (ventral waistband portion 2 and dorsal waistband portion 3). This makes it possible to make the waistband portion softer, further improving the feel and comfort of the garment.

In a preferred aspect of this embodiment, when the skin-side sheet and the non-skin-side sheet are made of nonwoven fabric, the average basis weight of the nonwoven fabric at 80% elongation is 9 to 19 g/ ^m2 . For example, in the ventral waistband 2, the skin-side sheet and the non-skin-side sheet are the first outer sheet 22 and the second outer sheet 23, respectively, and if they are nonwoven fabric, the average basis weight of the nonwoven fabric at 80% elongation is 9 to 19 g/ ^m2 . Similarly, in the back-side waistband 3, the skin-side sheet and the non-skin-side sheet are the first outer sheet 32 and the second outer sheet 33, respectively, and if they are nonwoven fabric, the average basis weight of the nonwoven fabric at 80% elongation is 9 to 19 g/ ^m2 . Note that when either the skin-side sheet or the non-skin-side sheet is the ventral stretchable sheet 21 or the back-side stretchable sheet 31, if it is a stretchable nonwoven fabric, the average basis weight of the nonwoven fabric at 80% elongation is 9 to 19 g/ ^m2 .

As described above, in the disposable diaper 1, the nonwoven fabric constituting the skin-side sheet and the non-skin-side sheet has a small average basis weight (9 to 19 g/m ² ) at 80% elongation. This reduces the bending rigidity of the nonwoven fabric, thereby increasing the flexibility of the entire waist region (ventral waist region 2 and dorsal waist region 3). This makes the waist region softer, further improving the feel and comfort.

In particular, when the average fiber diameter of the constituent fibers of the nonwoven fabrics constituting the skin-side sheet and the non-skin-side sheet is relatively small (5.0 to 17 μm) and the average basis weight at 80% elongation is low (9 to 19 g/m ² ), the rigidity of the entire waistband portion (ventral waistband portion 2 and dorsal waistband portion 3) is synergistically reduced. This allows the waistband portion to be more supple and flexible. This improves the conformability and feel to the skin, and further improves the feel and comfort.

In a preferred aspect of this embodiment, when the skin-side sheet and non-skin-side sheet are made of nonwoven fabric, the constituent fibers of these nonwoven fabrics are only long fibers. For example, in the ventral waistband portion 2, the skin-side sheet and non-skin-side sheet are the first outer sheet 22 and the second outer sheet 23, respectively, and if these are nonwoven fabrics, the constituent fibers of these nonwoven fabrics are only long fibers. Similarly, in the dorsal waistband portion 3, the skin-side sheet and non-skin-side sheet are the first outer sheet 32 and the second outer sheet 33, respectively, and if these are nonwoven fabrics, the constituent fibers of these nonwoven fabrics are only long fibers.

Types of long fiber nonwoven fabrics include, for example, spunbond nonwoven fabrics, meltblown nonwoven fabrics, flash-spun nonwoven fabrics, and combinations thereof, with spunbond nonwoven fabrics being preferred from the standpoint of flexibility. There are no particular restrictions on the type of long fiber, as long as it is a synthetic fiber, but examples include polyolefin fibers. Examples of polyolefin fibers include monofibers such as polypropylene fibers and polyethylene fibers, and core-sheath composite fibers made of polypropylene or polyethylene. Polypropylene fibers are preferred from the standpoint of flexibility. Therefore, spunbond nonwoven fabrics using polypropylene fibers are preferred for both the first outer sheet 22 and the second outer sheet 23, and the first outer sheet 32 and the second outer sheet 33.

In this way, in the disposable diaper 1, the nonwoven fabric that makes up the skin-side sheet and non-skin-side sheet is made entirely of long fibers. This increases the flexibility of the nonwoven fabric, and therefore increases the flexibility of the entire waistband portion (ventral waistband portion 2 and dorsal waistband portion 3). This makes the waistband portion softer, further improving the feel and comfort.

In a preferred aspect of this embodiment, when the skin-side sheet and the non-skin-side sheet are made of nonwoven fabric, the constituent fibers of these nonwoven fabrics include copolymer-blended fibers. For example, in the ventral waistband portion 2, the skin-side sheet and the non-skin-side sheet are the first outer sheet 22 and the second outer sheet 23, respectively, and if these are nonwoven fabrics, the constituent fibers of these nonwoven fabrics are copolymer-blended fibers. Similarly, in the dorsal waistband portion 3, the skin-side sheet and the non-skin-side sheet are the first outer sheet 32 and the second outer sheet 33, respectively, and if these are nonwoven fabrics, the constituent fibers of these nonwoven fabrics are copolymer-blended fibers.

Examples of copolymer-blended fibers include propylene-ethylene copolymer fibers and propylene-alpha olefin copolymer fibers.

In this way, in the disposable diaper 1, the constituent fibers of the nonwoven fabric that makes up the skin-side sheet and non-skin-side sheet contain copolymer-blended fibers. This improves the softness, particularly the suppleness, of the nonwoven fabric, further improving the suppleness of the entire waistband portion (ventral waistband portion 2 and dorsal waistband portion 3). This makes the waistband portion more supple, further improving the feel and comfort of the garment.

In a preferred aspect of this embodiment, when the skin-side sheet and non-skin-side sheet are made of nonwoven fabric, the nonwoven fabric contains a lubricant (softener). The lubricant is applied to at least one of the skin-side and non-skin-side surfaces of the nonwoven fabric. The lubricant may be applied to the entire surface of the nonwoven fabric, or to only a portion of the surface.

For example, in the ventral waistband portion 2, the skin-side sheet and non-skin-side sheet are the first outer sheet 22 and the second outer sheet 23, respectively, and if they are nonwoven fabrics, these nonwoven fabrics contain a lubricant. Similarly, in the dorsal waistband portion 3, the skin-side sheet and non-skin-side sheet are the first outer sheet 32 and the second outer sheet 33, respectively, and if they are nonwoven fabrics, these nonwoven fabrics contain a lubricant. Note that when either the skin-side sheet or the non-skin-side sheet is the ventral stretchable sheet 21 or the dorsal stretchable sheet 31, if it is a stretchable nonwoven fabric, then the nonwoven fabric contains a lubricant.

The type of lubricant is not particularly limited, as long as it can reduce the coefficient of friction at the applied position on the nonwoven fabric below the coefficient of friction before application. The coefficient of friction can be measured using an automated surface tester (KES-FB4-AUTO-A) or friction feel tester (KES-SE) manufactured by Kato Tech Co., Ltd. Furthermore, well-known application methods such as the slot die method can be used to apply the lubricant to the nonwoven fabric.

Lubricants include, for example, fatty acid amide compounds, silicone compounds, higher alcohols, surfactants, and combinations thereof. Of these, fatty acid amide compounds, modified silicone compounds, and higher alcohols are preferred. Examples of fatty acid amide compounds include fatty acid monoamide compounds, fatty acid diamide compounds, saturated fatty acid monoamide compounds, and unsaturated fatty acid diamide compounds. Specific examples include lauric amide, myristic amide, palmitic amide, stearic amide, behenic amide, oleic amide, erucic amide, montanic amide, N,N'-methylene-bis-lauric amide, N,N'-methylene-bis-myristic amide, N,N'-methylene-bis-palmitic amide, N,N'-methylene-bis-behenic amide, N,N'-methylene-bis-oleic amide, N,N'-methylene-bis-erucic amide, N,N'-ethylene-bis-oleic amide, and N,N'-ethylene-bis-erucic amide. Erucic amide is preferred from the viewpoint of feel on the skin. Examples of silicone-based compounds include modified silicone-based compounds and silicone-based polymers. Examples of modified silicone-based compounds include amino-modified silicones, diamino-modified silicones, and polyether-modified silicones. From the viewpoint of feel on the skin, amino-modified silicones and diamino-modified silicones are preferred. Examples of higher alcohols include lauryl alcohol, cetyl alcohol, stearyl alcohol, oleyl alcohol, and linoleyl alcohol. Stearyl alcohol is preferred from the perspective of feel on the skin.

In this way, in disposable diaper 1, the nonwoven fabrics constituting the skin-side sheet and non-skin-side sheet contain a lubricant (softener). This increases the slipperiness of the nonwoven fabric surface, reducing friction in the waistband sections (ventral waistband section 2 and dorsal waistband section 3). This makes the waistband sections smooth against the skin, reducing damage caused by friction on the skin surface when worn. This further improves the feel and comfort of the diaper.

In a preferred embodiment of this embodiment, the stretchable sheet and the non-stretchable adjacent sheet are joined by multiple welds formed by ultrasonic welding. The multiple welds may be arranged over the entire stretchable sheet and the non-stretchable adjacent sheet, or may be arranged partially. The multiple welds in this embodiment are described below with reference to Figures 5 and 6.

Figure 5 is a schematic diagram showing an example of the configuration of an ultrasonic bonding region, which is a region where multiple welds are arranged, according to an embodiment. In this embodiment, in the ventral waistline portion 2, the stretchable sheet is the ventral stretchable sheet 21, and the non-stretchable adjacent sheet is the first outer sheet 22 and the second outer sheet 23. The multiple welds are arranged in the entire region of the ventral waistline portion 2, excluding the regions of the outer ends of the ventral waistline portion 2 in the longitudinal direction L, in a planar view. Therefore, the ultrasonic bonding region, which is a region where multiple welds are arranged, is the entire region of the ventral waistline portion 2, excluding the regions of the outer ends of the ventral waistline portion 2 in the longitudinal direction L. However, in a planar view, the ultrasonic bonding region includes a second ultrasonic bonding region P2, which is a region overlapping the center of the absorbent main body 10, and a first ultrasonic bonding region P1, which is the remaining region. The first ultrasonic bonding region P1 and the second ultrasonic bonding region P2 have different arrangement patterns and have welds of different shapes. However, the central portion of the absorbent main body 10 refers to the region excluding both ends of the absorbent main body 10 in the longitudinal direction L and the width direction W. The regions having different arrangement patterns and/or differently shaped welded regions are not limited to the two types described above, and may include one, three, or more types of regions. The ultrasonically bonded regions with differently shaped welds do not require the provision of a second exterior sheet 23.

Similarly, in this embodiment, in the back waist portion 3, the stretchable sheet is the back stretchable sheet 31, and the non-stretchable adjacent sheets are the first outer sheet 32 and the second outer sheet 33. The multiple welded portions are arranged in a plan view across the entire back waist portion 3, excluding the outer end portions of the back waist portion 3 in the longitudinal direction L. Therefore, the ultrasonic bonding region, which is the region where the multiple welded portions are arranged, is the entire back waist portion 3, excluding the outer end portions of the back waist portion 3 in the longitudinal direction L. However, the ultrasonic bonding region includes a second ultrasonic bonding region P2, which is an area overlapping the center of the absorbent main body 10, and a first ultrasonic bonding region P1, which is the remaining area. The relationship between the first ultrasonic bonding region P1 and the second ultrasonic bonding region P2, the arrangement pattern, and the shape of the welded portions are the same as those in the ventral waist portion 2 described above. However, the central portion of the absorbent main body 10 refers to the region excluding both end portions in the longitudinal direction L and width direction W of the absorbent main body 10. The arrangement pattern and shape of the welded portions, as well as the number and type of regions in which they are arranged, may be different or the same between the ventral waistline portion 2 and the dorsal waistline portion 3. The second exterior sheet 33 may not be provided.

However, the "end" on one side/other side in the longitudinal direction L of a certain configuration (e.g., the absorbent main body 10) refers to an area from the edge on one side/other side in the longitudinal direction L of the configuration that is preferably within 30%, more preferably within 20%, and even more preferably within 10% of the length of the configuration in the longitudinal direction L. Similarly, the "end" on one side/other side in the width direction W of a certain configuration refers to an area from the edge on one side/other side in the width direction W of the configuration that is preferably within 30%, more preferably within 20%, and even more preferably within 10% of the length of the configuration in the width direction W.

Figure 6 is a schematic diagram showing an example of a pattern of welds formed by ultrasonic bonding according to an embodiment. Figure 6(a) is a schematic diagram showing an example of an arrangement pattern of multiple welds 41 in the first ultrasonic bonding region P1. The multiple welds 41 have a rectangular shape with a long side d1 and a short side d2, and are arranged in a staggered pattern. Adjacent (closest) welds are rotated (shifted) by 90 degrees from each other. In other words, the long sides of welds 41a and 41b are rotated (shifted) by 90 degrees from each other. However, the arrangement pattern of the multiple welds and the shape of each weld are not limited to this example, and known arrangements and shapes can be used.

Similarly, Figure 6(b) is a schematic diagram showing an example of an arrangement pattern of multiple welds 42 in the second ultrasonic bonding region P2. The multiple welds 42 have a rectangular shape with long sides d3 and short sides d4, and are arranged in a staggered pattern. Adjacent (closest) welds are rotated (shifted) by 90 degrees from each other. In other words, the long sides of welds 42a and 42b are rotated (shifted) by 90 degrees from each other. However, the arrangement pattern of the multiple welds and the shape of each weld are not limited to this example, and known arrangements and shapes can be used.

Here, the area of the welded portion 42 is larger than the area of the welded portion 41. In the example of Figure 6, d3 > d1 and d4 ≥ d2. Furthermore, the distance D2 between the welded portions 42 is the same as or smaller than the distance D1 between the welded portions 41. In the example of Figure 6, D2 ≥ D1. This is because the multiple welded portions 42 are located in the area corresponding to the crotch area, which is prone to deformation due to the application of force during use, i.e., the second ultrasonic bonding area P2, and therefore require a higher bonding strength.

In this way, in the disposable diaper 1, the stretchable sheets (ventral stretchable sheet 21/dorsal stretchable sheet 31) and the non-stretchable adjacent sheets (first outer sheet 22 (second outer sheet 23)/first outer sheet 32 (second outer sheet 33)) are joined at multiple welds 41, 42 formed by ultrasonic welding. This allows the individual joints to be small, which in turn allows for more precise wrinkles to be formed in the waistband portion (ventral waistband portion 2/dorsal waistband portion 3) by the stretchable sheets. Furthermore, because the diapers are not joined with adhesive, there is no hardness when the adhesive hardens. This improves the flexibility of the waistband as a whole, and the diaper feels supple when picked up or worn, thereby further improving the feel and comfort of the diaper.

In a preferred aspect of this embodiment, in the disposable diaper 1, the multiple types of welded sections 41, 42 are arranged in a staggered pattern in the waistband section (ventral waistband section 2/dorsal waistband section 3). This maintains continuity in the welded sections 41, 42 joining the stretchable sheets (ventral stretchable sheet 21/dorsal stretchable sheet 31) and the non-stretchable adjacent sheets (first outer sheet 22 (second outer sheet 23)/first outer sheet 32 (second outer sheet 33)). Furthermore, having multiple types of welded sections 41, 42 reduces continuity in the stretch direction (width direction W). Therefore, contraction of the stretchable sheet allows numerous fine folds to be formed in the waistband section. This results in a texture that is both thin and soft in the compression direction. This provides a fluffy softness when picked up or worn, further improving the feel and comfort of the diaper.

In a preferred aspect of this embodiment, the waistband portions, i.e., the ventral waistband portion 2 and the back waistband portion 3, extend along the width direction W at the center of the longitudinal direction L, are joined by multiple welds, and have an adhesive-free area NA where no adhesive is applied. The range of the adhesive-free area NA, for example, is at least 25 mm of the length of the ventral waistband portion 2 and the back waistband portion 3 in the longitudinal direction L, and at least two-thirds of the length of the centers of the ventral waistband portion 2 and the back waistband portion 3 in the width direction W. Preferably, the adhesive-free area NA is between a pair of fastening portions 2a, 2a/3a, 3a in the width direction W. In the example of Figure 1, the adhesive-free area NA of the ventral waistband portion 2 excludes the waist elastic member 25 and the leg elastic member 26 in the longitudinal direction L, and is between a pair of fastening portions 2a, 2a in the width direction W. Similarly, the non-adhesive application area NA of the back waistband portion 3 is the area excluding the waist elastic members 35 and leg elastic members 36 in the longitudinal direction L, and is the area between the pair of fastening portions 3a, 3a in the width direction W.

In this way, in the disposable diaper 1, the stretchable sheet and the non-stretchable adjacent sheet are joined at multiple welded portions 41, 42 as described above, and as a result, the waist portion (ventral waist portion 2/dorsal waist portion 3) has an adhesive-free area NA that occupies a wide area of the waist portion and is joined by multiple welded portions 41, 42 but is not coated with adhesive. While the use of adhesive tends to increase the rigidity of the waist portion, the existence of such a large adhesive-free area reduces the rigidity of the waist portion and improves its flexibility. Therefore, the diaper can be felt as soft when picked up or worn, further improving the feel and comfort.

In the above embodiment, it is preferable that a strip-shaped portion of the back waistband 3, extending widthwise and measuring 25 mm or more at the upper end of the non-adhesive-applied area NA in the longitudinal direction L, is composed only of the stretchable sheet (back stretchable sheet 31) and the non-stretchable adjacent sheets (first outer sheet 32, second outer sheet 33). The range of this strip-shaped portion in the width direction W is, for example, at least two-thirds of the length of the center of the back waistband 3, and preferably extends between the pair of fastening portions 3a, 3a in the width direction W. In the example of Figure 1, the strip-shaped portion extends 25 to 40 mm in the longitudinal direction L at the end of the back waistband 3 on the waist opening side, excluding the area where the waist elastic member 35 is located, and extends between the pair of fastening portions 3a, 3a in the width direction W.

Alternatively, it is preferable that the ventral waistline portion 2 has a strip-shaped portion of 25 mm or more at the upper end in the longitudinal direction L of the non-adhesive-applied area NA, which is composed only of the stretchable sheet (ventral stretchable sheet 21) and the non-stretchable adjacent sheets (first outer sheet 22, second outer sheet 23). The range of this strip-shaped portion in the width direction W is, for example, at least two-thirds of the length of the center of the ventral waistline portion 2, and preferably the range in the width direction W between the pair of fastening portions 2a, 2a. In the example of Figure 1, the strip-shaped portion is the end of the ventral waistline portion 2 on the waist opening side, excluding the area where the waist elastic member 25 is arranged, and is the range of 25 to 50 mm in the longitudinal direction L and the range between the pair of fastening portions 2a, 2a in the width direction W.

In this case, the belt-like portion comes into contact with the iliac crest or its vicinity, which is a protruding part of the wearer's waist, and is a part that strongly influences comfort. Because the belt-like portion of the dorsal waistband or ventral waistband is composed only of the non-adhesive area NA and the stretchable sheet and non-stretchable adjacent sheet, the wearer can feel a greater softness and flexibility when wearing the garment, thereby further improving the feel and comfort.

When belt-like portions are present in both the dorsal waistband and ventral waistband, these belt-like portions come into contact with the iliac crest, a protruding part of the wearer's waist, or its vicinity, and are therefore parts that have a significant impact on comfort. Because the belt-like portions in both the dorsal waistband and ventral waistband are composed only of the non-adhesive area NA and the stretchable sheet and non-stretchable adjacent sheet, the wearer can feel a greater softness and flexibility when wearing the garment, thereby further improving the feel and comfort.

In a preferred aspect of this embodiment, the skin-side sheet and the non-skin-side sheet are made of nonwoven fabric, and the constituent fibers of the nonwoven fabric include recycled fibers. Examples of recycled fibers include rayon, which includes viscose rayon, polynosic, and modal obtained from viscose, and cuprammonium rayon (also known as "cupra") obtained from a cuprammonium salt solution of cellulose. The inclusion of recycled fibers in the constituent fibers of the nonwoven fabric improves the suppleness and smoothness of the nonwoven fabric, thereby improving the feel of the waistband portion (ventral waistband portion 2/dorsal waistband portion 3). This improves the fit of the waistband to the skin, reducing skin problems such as rashes caused by friction. This further improves the feel and comfort of the garment.

In a preferred aspect of this embodiment, the skin-side sheet and non-skin-side sheet are made of nonwoven fabric, and the constituent fibers of the nonwoven fabric include cotton. Examples of cotton include Hirsutum cotton (e.g., upland cotton), Barbadense cotton, Arboreum cotton, and Helbaceum cotton. Cotton may also be organic cotton or pre-organic cotton (trademark). However, organic cotton refers to cotton certified by GOTS (Global Organic Textile Standard). Because cotton has rounded fiber tips compared to synthetic fibers, including cotton as a constituent fiber of the nonwoven fabric makes the nonwoven fabric less likely to irritate the skin. In other words, cotton is not rough or prickly to the touch, and does not cause any discomfort when worn. This further improves the feel and comfort of the fabric.

In a preferred aspect of this embodiment, the skin-side sheet and non-skin-side sheet (nonwoven fabric) are non-stretchable adjacent sheets, and the stretchable sheet (nonwoven fabric) is disposed between the skin-side sheet and non-skin-side sheet. The average basis weight of one of the stretchable sheet and non-stretchable adjacent sheet at 80% elongation is 1.0 to 1.3 times the average basis weight of the other at 80% elongation. In other words, the average basis weight of the larger of the stretchable sheet and non-stretchable adjacent sheet at 80% elongation is 1.0 to 1.3 times that of the smaller. Therefore, the average basis weights of the stretchable sheet and non-stretchable adjacent sheet at 80% elongation are roughly the same.

In the example shown in Figures 1 to 4, in the ventral waistband portion 2, the skin-side sheet and non-skin-side sheet are the first outer sheet 22 (non-stretchable adjacent sheet) and the second outer sheet 23 (non-stretchable adjacent sheet), and the stretchable sheet (ventral-side stretchable sheet 21) is disposed between the first outer sheet 22 and the second outer sheet 23. The average basis weight of one (the larger) of the ventral-side stretchable sheet 21 and the first outer sheet 22 (or the second outer sheet 23) at 80% elongation is 1.0 to 1.3 times the average basis weight of the other (the smaller) at 80% elongation.

Similarly, in the back waistband portion 3, the skin-side sheet and non-skin-side sheet are the first outer sheet 32 (non-stretchable adjacent sheet) and the second outer sheet 33 (non-stretchable adjacent sheet), and the stretchable sheet (back stretchable sheet 31) is disposed between the first outer sheet 32 and the second outer sheet 33. The average basis weight of one (the larger) of the back stretchable sheet 31 and the first outer sheet 32 (or the second outer sheet 33) at 80% elongation is 1.0 to 1.3 times the average basis weight of the other (the smaller) at 80% elongation.

The feel and comfort of disposable diaper 1 can also be affected by the configuration of the stretchable sheets (ventral stretchable sheet 21/dorsal stretchable sheet 31) interposed between the skin-side and non-skin-side sheets, for example, their average basis weight. Therefore, in disposable diaper 1, not only the skin-side and non-skin-side sheets (first outer sheet 22 and second outer sheet 23/first outer sheet 32 and second outer sheet 33) but also the stretchable sheets (ventral stretchable sheet 21/dorsal stretchable sheet 31) are nonwoven fabrics, and their average basis weights at 80% elongation are roughly the same. This makes it possible to further reduce the gap between the feel attributed to the non-skin-side sheets, including the stretchable sheets, and the comfort attributed to the skin-side sheets, including the stretchable sheets. Furthermore, a low average basis weight reduces the rigidity of the entire waistband (ventral waistband 2 and dorsal waistband 3), allowing the waistband to have supple flexibility. This improves the fabric's ability to conform to the skin and feel better, further improving the feel and comfort of the garment.

In addition, in the disposable diaper 1, non-stretchable sheets (first outer sheet 22 and second outer sheet 23 / first outer sheet 32 and second outer sheet 33) are sandwiched between stretchable sheets (ventral stretchable sheet 21 / dorsal stretchable sheet 31) on both the skin-facing and non-skin-facing sides. Therefore, as the stretchable sheets contract, unevenness is formed in each non-stretchable sheet. In other words, unevenness is created on the surface of the waistband portion (ventral waistband portion 2 and dorsal waistband portion 3). These unevenness imparts flexibility to the waistband portion, giving it a fluffy feel to the wearer. This further improves the comfort of wearing an absorbent article.

In a preferred aspect of this embodiment, the non-stretchable adjacent sheets (first outer sheet 22 and second outer sheet 23 / first outer sheet 32 and second outer sheet 33) are nonwoven fabrics, and the stretchable sheets (ventral stretchable sheet 21 / dorsal stretchable sheet 31) are stretchable nonwoven fabrics. In this way, in disposable diaper 1, the stretchable sheets are stretchable nonwoven fabrics, which provide good conformity to the non-stretchable adjacent sheets, which are nonwoven fabrics. Furthermore, the average basis weights of the stretchable sheets and non-stretchable adjacent sheets at 80% elongation are roughly the same. This further reduces the gap between the feel of the non-skin-side sheets, including the stretchable sheets, and the comfort of wearing the skin-side sheets, including the stretchable sheets.

In a preferred aspect of this embodiment, the average basis weight of the non-stretchable adjacent sheets (first outer sheet 22 and second outer sheet 23 / first outer sheet 32 and second outer sheet 33) and the stretchable sheets (ventral stretchable sheet 21 / dorsal stretchable sheet 31) at 80% elongation is 9 to 17 g/ ^m2 . In this manner, in the disposable diaper 1, the average basis weight of the non-stretchable adjacent sheets and the stretchable sheets at 80% elongation is small (9 to 17 g/ ^m2 ), allowing the bending rigidity of the nonwoven fabric to be reduced. This further reduces the rigidity of the entire waist portion (ventral waist portion 2 and dorsal waist portion 3), allowing the waist portion to have a supple flexibility. This improves the conformability and feel against the skin, further improving the feel and comfort.

The present invention will be explained below based on examples, but the present invention is not limited to these examples.

(1) Sample (a) Example 1
Disposable diapers for adults having the configurations shown in Figures 1 to 6 described in the above embodiment were used. The waistband portions (ventral waistband portion 2 and dorsal waistband portion 3) had stretchable sheets (ventral stretchable sheet 21 and dorsal stretchable sheet 31) and non-stretchable sheets (first outer sheet 22 and second outer sheet 23 and first outer sheet 32 and second outer sheet 33). However, the skin-side sheets were first outer sheet 22 and first outer sheet 32, and the non-skin-side sheets were second outer sheet 23 and second outer sheet 33. Both the skin-side sheets and non-skin-side sheets were spunbond nonwoven fabrics, and the stretchable sheets were stretchable nonwoven fabrics.
(b) Comparative Examples 2 to 4
Three types of commercially available adult disposable diapers manufactured by different manufacturers were used as Comparative Examples 1 to 3.
In Comparative Example 1, the skin side sheet and non-skin side sheet were non-stretchable sheets, and a stretchable sheet was provided between the skin side sheet and the non-skin side sheet. The skin side sheet was an SMS nonwoven fabric, but the non-skin side sheet was a spunbond nonwoven fabric, and the stretchable sheet was a stretchable nonwoven fabric with a relatively high average basis weight.
In Comparative Example 2, the skin-side sheet was a non-stretch sheet, but the non-skin-side sheet was a stretch sheet. The stretch sheet was an elastic sheet and had two nonwoven fabrics with an elastomer between them. The skin-side sheet was a spunbond nonwoven fabric.
In Comparative Example 3, the skin-side sheet and the non-skin-side sheet were non-stretchable sheets, and a stretchable sheet was disposed between the skin-side sheet and the non-skin-side sheet. The stretchable sheet was a stretchable film having a plurality of through-holes. The skin-side sheet and the non-skin-side sheet were spunbond nonwoven fabrics.

(2) Evaluation Method (a) Average basis weight and average fiber diameter For the skin-side sheet and non-skin-side sheet in the disposable diapers of Example 1 and Comparative Examples 1 to 3, the average basis weight at 80% elongation and the average fiber diameter of the constituent fibers were measured using the measurement method described above.
(b) Texture (touch) and feel (comfort)
Evaluators A to E (a total of five men and women in their 40s to 60s) were asked to make the following evaluations.
- Evaluation items (a) The feel of the disposable diaper from the time it is taken out of the individual packaging until it is put on. The "feel" is evaluated on a 10-point scale from 1 (bad) to 10 (good). In this case, the higher the number, the better the result.
(b) Feeling of the disposable diaper on the skin immediately after putting it on. The "feel of the diaper on the skin" was evaluated on a scale of 1 (bad) to 10 (good). In this case, the higher the number, the better the result.
(c) Gap between feel before wearing and feel after wearing The gap was evaluated on the following 4-point scale: 1: The feel before wearing was good, and the feel after wearing was also good.
(It feels comfortable both before and after wearing, and there is little difference.)
2: The fabric feels good before wearing, but the feel after wearing is unsatisfactory.
(The feel before wearing is good, but the comfort is not enough, so there is a big gap.)
3: The feel before wearing is unsatisfactory, but the feel after wearing is good.
(It's not enough before wearing, but it's comfortable and the gap is big)
4: The feel before wearing is unsatisfactory, and the feel after wearing is unsatisfactory as well (both before and after wearing are unsatisfactory, so the gap is small)
In this case, the smaller the number, the better the results.

(3) Evaluation Results (a) Average Basis Weight and Average Fiber Diameter (a-1) Example 1
In Example 1, the average basis weight of one of the skin-side sheet and the non-skin-side sheet at 80% elongation was 1.0 to 1.3 times the average basis weight of the other at 80% elongation, and the average fiber diameter of the constituent fibers of one was 1.0 to 1.5 times the average fiber diameter of the constituent fibers of the other. Furthermore, the average basis weight of the nonwoven fabrics of the skin-side sheet and the non-skin-side sheet at 80% elongation was within a predetermined range (9 to 19 g/m ² ), and the average fiber diameter of the constituent fibers of the nonwoven fabric was within a predetermined range (5.0 to 17 μm).
(a-2) Comparative Examples 1 to 3
In Comparative Example 1, the average basis weight of one of the skin-side and non-skin-side sheets at 80% elongation was 1.0 to 1.3 times the average basis weight of the other at 80% elongation. However, the average fiber diameter of the constituent fibers of one was 2.61 times, or more than 1.5 times, the average fiber diameter of the constituent fibers of the other. Furthermore, the average basis weight of the nonwoven fabric of the skin-side sheet at 80% elongation was outside the specified range (20 g/m ² ). In addition, the average fiber diameter of the constituent fibers making up the nonwoven fabric of the non-skin-side sheet was outside the specified range (18.2 μm).
In Comparative Example 2, the average fiber diameter of the constituent fibers of one of the skin-side and non-skin-side sheets was 1.0 to 1.5 times the average fiber diameter of the constituent fibers of the other. However, the average basis weight of one sheet at 80% elongation was 1.35 times, or more than 1.3 times, the average basis weight of the other sheet at 80% elongation. Furthermore, the average fiber diameters of the constituent fibers making up the nonwoven fabric of the skin-side and non-skin-side sheets were within the specified range. However, the average basis weights of the nonwoven fabric of the skin-side and non-skin-side sheets at 80% elongation both exceeded the specified range (23 g/m ² , 33 g/m ² ).
In Comparative Example 3, the average basis weight of one of the skin-side and non-skin-side sheets at 80% elongation was 1.5 times, or more than 1.3 times, the average basis weight of the other at 80% elongation. Furthermore, the average fiber diameter of one of the constituent fibers was 2.3 times, or more than 1.5 times, the average fiber diameter of the other. Furthermore, the average basis weight of the nonwoven fabric of the non-skin-side sheet at 80% elongation was outside the specified range (21 g/ ^m2 ).
(c) Summary The above evaluation results are shown in the following Table 1. It was found that the disposable diaper 1 of Example 1 has a configuration that satisfies the predetermined conditions, but the disposable diapers of Comparative Examples 1 to 3 do not satisfy some of the predetermined conditions that the disposable diaper 1 of Example 1 satisfies.

*Here, (large/small) indicates that the larger of the value for the non-skin side sheet and the value for the skin side sheet is divided by the smaller value.

(b) Texture (touch) and feel (comfort)
(b-1) Example 1
The average score for the feel of the disposable diaper from the time it was taken out of the individual packaging until it was put on was 8.8. Therefore, the diaper received a high rating for the feel before it was put on.
In addition, the average score for the feel of the disposable diaper on the skin immediately after putting it on was 8.6, which means that the diaper was also highly rated in terms of how nice it felt on the skin immediately after putting it on.
Furthermore, the average score for the difference between the feel before and after wearing was 1. Therefore, the garment was highly rated for being comfortable both before and after wearing, and for the small difference between the feel before and after wearing.
(b-2) Comparative Examples 1 to 3
The average scores for the feel of the disposable diaper from the time it was taken out of the individual packaging bag until it was put on were "5.8", "6.6", and "5", respectively. Therefore, the evaluation of the feel before putting it on was lower than that of Example 1.
Furthermore, the average values for the feel on the skin immediately after putting on the disposable diaper were "6.8", "6.6", and "6", respectively. Therefore, the evaluation of the feel on the skin immediately after putting on the diaper was also lower than that of Example 1.
Furthermore, the average values for the gap between the feel before wearing and the feel after wearing were "2.6,""2.6," and "2.8," respectively. Therefore, many of the evaluations pointed out at least one of the following: the feel before wearing was insufficient, and the feel after wearing was insufficient. This indicates that there was a large gap between the feel before wearing and the feel after wearing, or that the feel before and after wearing was insufficient, resulting in a lower evaluation compared to Example 1.
(c) Summary The above evaluation results are shown in the following Table 2. Comparing Example 1 with Comparative Examples 1 to 3, it was confirmed that Example 1 is superior to Comparative Examples 1 to 3 in terms of the feel felt before wearing, the feel felt immediately after wearing, and the gap between the feel before wearing and the feel after wearing.

The absorbent article of the present invention is not limited to the disposable diapers of the above-mentioned embodiments, and it is possible to combine the embodiments or apply publicly known technologies within the scope of the purpose and intent of the present invention.

REFERENCE SIGNS LIST 1 absorbent article 11 absorbent body 11a absorbent core 11b1 skin-side core wrap sheet 11b2 non-skin-side core wrap sheet

Claims (9)

An absorbent article having a longitudinal direction, a width direction, and a thickness direction which are perpendicular to one another in an unfolded state, and comprising a waist portion which covers the waist of a wearer, and an absorbent main body which covers the crotch area and includes an absorbent body,
The waist portion is
a stretchable sheet extending in the width direction and having stretchability in the width direction;
a non-stretchable adjacent sheet adjacent to the skin side and non-skin side of the stretchable sheet, and
Including,
the skin-side sheet constituting the skin-side surface of the waistband portion and the non-skin-side sheet constituting the non-skin-side surface are the non-stretchable adjacent sheets,
the skin side sheet and the non-skin side sheet are separate sheets,
the stretchable sheet is disposed between the skin side sheet and the non-skin side sheet,
the skin side sheet and the non-skin side sheet are nonwoven fabrics,
the average basis weights of the skin side sheet and the non-skin side sheet at 80% elongation are such that the larger one is 1.0 to 1.3 times the smaller one;
the average fiber diameter of the constituent fibers of the skin side sheet and the non-skin side sheet is 1.0 to 1.5 times that of the smaller one;
the average basis weight of the stretchable sheet and the non-stretchable adjacent sheet at 80% elongation is 1.0 to 1.3 times that of the smaller one;
The average fiber diameter of the constituent fibers of the nonwoven fabric is 5.0 to 17 μm,
The nonwoven fabric has an average basis weight of 9 to 19 g/ ^m2 at 80% elongation,
the stretchable sheet and the non-stretchable adjacent sheet are joined by a plurality of welds formed by ultrasonic welding;
the waistband portion has an ultrasonic bonding region in which the plurality of welded portions are arranged,
The ultrasonic bonding region has, in a plan view, a second ultrasonic bonding region which is a region overlapping with the central portion of the absorbent main body, and the first ultrasonic bonding region which is the other region,
The plurality of welded portions have different arrangement patterns and/or different shapes in the first ultrasonic bonding region and the second ultrasonic bonding region.
Absorbent articles. The stretchable sheet is a stretchable nonwoven fabric.
The absorbent article of claim 1. the waistband portion has a non-adhesive-applied region extending along the width direction at a center in the longitudinal direction, joined by the plurality of welded portions, and having no adhesive applied thereto;
In either the back waist portion covering the waist on the back side of the wearer or the ventral waist portion covering the waist on the ventral side of the wearer, a strip-shaped portion of 25 mm or more at the upper end in the longitudinal direction of the non-adhesive application area is composed only of the stretchable sheet and the non-stretchable adjacent sheet.
The absorbent article according to claim 1 or 2. In both the back waist portion and the ventral waist portion, a strip-shaped portion of 25 mm or more at the upper end in the longitudinal direction of the non-adhesive application area is composed only of the stretchable sheet and the non-stretchable adjacent sheet.
The absorbent article of claim 3. The constituent fibers of the nonwoven fabric of the skin side sheet and the non-skin side sheet are long fibers only.
The absorbent article according to claim 1 or 2. The constituent fibers of the nonwoven fabric of the skin side sheet and the non-skin side sheet contain copolymer-blended fibers.
The absorbent article according to claim 1 or 2. The nonwoven fabrics of the skin side sheet and the non-skin side sheet contain a lubricant.
The absorbent article according to claim 1 or 2. The constituent fibers of the nonwoven fabric of the skin side sheet and the non-skin side sheet contain recycled fibers.
The absorbent article according to claim 1 or 2. The constituent fibers of the nonwoven fabric of the skin side sheet and the non-skin side sheet contain cotton.
The absorbent article according to claim 1 or 2.