Disposable diaper

Abstract

A purpose of the present disclosure is to provide a disposable diaper that is easy to put on by passing the legs through leg gather portions, that is unlikely to leave marks on the wearer's legs after being put on, and that is unlikely to leak.　A disposable diaper (1) is characterized in that in an unfolded state, each of a pair of leg gather portions (23) includes a fabric (33) having a widthwise outer edge (37) located at the outermost side in the widthwise direction (W), and a plurality of thread-like elastic members (31) fixed to the fabric (33) so as to extend in the lengthwise direction (L) on the inner side in the widthwise direction (W) of the widthwise outer edge (37), the plurality of thread-like elastic members (31) include a first thread-like elastic member (31a) and a second thread-like elastic member (31b), and a first distance (41D) is longer than a second distance (43D) in intersection portions where a widthwise centerline (CW) and each of the pair of leg gather portions (23) intersect.

Description

Disposable diapers

[0001] The present disclosure relates to disposable diapers.

[0002] Disposable diapers have been studied. For example, Patent Document 1 discloses a pants-type disposable wearing article having a longitudinal direction and a transverse direction perpendicular thereto, including a skin-facing surface and a non-skin-facing surface, a front waist region, a rear waist region, a crotch region located between the front and rear waist regions, and a liquid-absorbent structure disposed at least in the crotch region, and having a waist opening and a pair of leg openings defined by joining both side edges of the front and rear waist regions together, the crotch region having a pair of elastic side flaps located outward in the transverse direction of both side edges of the liquid-absorbent structure, The elastic side flaps have front and rear end portions fixed outward in the lateral direction in the front and rear waist regions, an inelastic region extending outward in the lateral direction from the side edge of the liquid-absorbent structure, and an elastic region extending outward in the lateral direction from the inelastic region, the elastic region being divided into a first elastic region located on the outer edge side of the elastic side flap and a second elastic region located inside the lateral direction of the first elastic region, and the wearing article is characterized in that the elongation stress of the first elastic region is lower than the elongation stress of the second elastic region.

[0003] JP 2014-171692 A

[0004] Patent Document 1 does not disclose the disposable diaper according to the present disclosure. The present disclosure aims to provide a disposable diaper that is easy to put on and that is less likely to leave marks on the wearer's legs when worn, and is less likely to leak.

[0005] The present inventors have proposed a disposable diaper which, in an unfolded state, has a longitudinal direction, a width direction, and a thickness direction that are orthogonal to one another, and which comprises a ventral portion, a dorsal portion, and a crotch portion between the ventral portion and the dorsal portion, and which defines a waist opening and a pair of leg openings by connecting both side edges in the width direction of the ventral portion and both side edges in the width direction of the dorsal portion, and which comprises a pair of leg gathering portions in the crotch portion that form the pair of leg openings and that stretch in the longitudinal direction, and in the unfolded state, each of the pair of leg gathering portions comprises a fabric having a widthwise outer edge located at the outermost side in the width direction, and a fabric having a widthwise outer edge located at the inner side in the width direction of the widthwise outer edge and a waist opening and a leg ... and a plurality of thread-like elastic members fixed to the fabric so as to extend in a width direction, the plurality of thread-like elastic members including a first thread-like elastic member closest to the widthwise outer edge and a second thread-like elastic member adjacent to the first thread-like elastic member, and when the region defined by the widthwise outer edge and the first thread-like elastic member is defined as a first region, and the region defined by the first thread-like elastic member and the second thread-like elastic member is defined as a second region, at an intersection where a widthwise centerline extending parallel to the width direction at the longitudinal center of the disposable diaper intersects with each of the pair of leg gathered portions, a first distance which is the width of the first region in the width direction is longer than a second distance which is the width of the second region in the width direction.

[0006] The disposable diaper according to the present disclosure is easy to put on by passing the legs through the leg gathers, and is less likely to leave marks on the wearer's legs while being worn, and is less likely to leak.

[0007] FIG. 1 is a diagram illustrating a disposable diaper 1 according to a first embodiment. FIG. 2 is a diagram illustrating a disposable diaper 1 according to the first embodiment. FIG. 3 is a diagram illustrating a disposable diaper 1 according to the first embodiment. FIG. 4 is a diagram illustrating a disposable diaper 1 according to the first embodiment. FIG. 5 is a diagram illustrating a disposable diaper 1 according to the first embodiment. FIG. 6 is a diagram illustrating a disposable diaper 1 according to the first embodiment. FIG. 7 is a diagram illustrating a disposable diaper 1 according to the first embodiment. FIG. 8 is a diagram illustrating a disposable diaper 1 according to the first embodiment. FIG. 9 is a diagram illustrating a disposable diaper 1 according to the first embodiment.

[0008] Specifically, the present disclosure relates to the following aspects: [Aspect 1] A disposable diaper having, in an unfolded state, longitudinal, width, and thickness directions that are orthogonal to one another, comprising a ventral portion, a dorsal portion, and a crotch portion between the ventral portion and the dorsal portion, and wherein both sides in the width direction of the ventral portion and both sides in the width direction of the dorsal portion are connected to define a waist opening and a pair of leg openings, wherein the disposable diaper comprises, in the crotch portion, a pair of leg gathering portions that form the pair of leg openings and are stretchable in the longitudinal direction, and in the unfolded state, each of the pair of leg gathering portions comprises a fabric having a widthwise outer edge located at the outermost side in the width direction, and a plurality of thread-like elastic members fixed to the fabric so as to extend in the longitudinal direction on a side more inward in the width direction than the widthwise outer edge, and the plurality of thread-like elastic members comprises a first thread-like elastic member closest to the widthwise outer edge and a second thread-like elastic member adjacent to the first thread-like elastic member, When the region defined by the widthwise outer edge and the first thread-like elastic member is defined as a first region, and the region defined by the first thread-like elastic member and the second thread-like elastic member is defined as a second region, at an intersection where a widthwise centerline extending parallel to the width direction at the longitudinal center of the disposable diaper intersects with each of the pair of leg gathered portions, a first distance which is the width of the first region in the width direction is longer than a second distance which is the width of the second region in the width direction.

[0009] The disposable diaper is configured such that the first distance in the first region is longer than the second distance in the second region at the widthwise center and at each intersection of a pair of leg gathers. As a result, in the disposable diaper in its natural state, the first region is less likely to contract than the second region at the intersection, making it easier for ruffles to form on the widthwise outer edges of the leg gathers at the intersection (hereinafter, the ease of ruffle formation may be referred to as "ruffle formability").

[0010] The widthwise center line constituting the intersecting portion is the portion that is most likely to come into contact with the wearer's legs when putting on the disposable diaper. For example, when a wearer puts on a pants-type disposable diaper in an upright position, or when a caregiver helps a wearer put on a pants-type disposable diaper in an upright position, the widthwise center line constituting the intersecting portion is located at the lowest position and is most likely to come into contact with the wearer's legs. Also, for example, when a caregiver helps a wearer put on a tape-type disposable diaper in a supine position, the widthwise center line constituting the intersecting portion is most likely to come into contact with the wearer's legs.

[0011] In this specification, the cases where a wearer puts on a pants-type disposable diaper in an upright position, where an assistant puts on a pants-type disposable diaper on a wearer in an upright position, and where an assistant puts on a tape-type disposable diaper on a wearer in a lying position are sometimes simply referred to as "when putting on."

[0012] Therefore, compared to conventional disposable diapers (hereinafter sometimes simply referred to as "conventional disposable diapers") in which the leg gathers have the same contractile force when put on but the first distance in the first region is not longer than the second distance in the second region, the wearer's legs are less likely to get caught on the frills formed in the first region of the leg openings when putting their legs through the pair of leg openings, making it easier to put their legs through (hereinafter, ease of putting their legs through may be referred to as "leg passageability"). Furthermore, as a result of the excellent leg passageability, the wearer or caregiver will need to adjust the disposable diaper less when putting it on, which makes it easier for the wearer or caregiver to feel reassured that the disposable diaper will not leak (hereinafter, providing a sense of security may be referred to as "security-providing ability").

[0013] In conventional disposable diapers, when the disposable diaper is worn (hereinafter, sometimes simply referred to as "during wear"), the wearer's legs generally tend to be clamped by the widthwise outer edges of the pair of leg gathers, which tends to leave marks on the wearer's legs from the widthwise outer edges. In contrast, the disposable diaper described above is configured so that the first distance in the first region is longer than the second distance in the second region at the intersection, and therefore the widthwise outer edges of the leg gathers are less likely to leave marks on the wearer's legs while the diaper is worn (hereinafter, the resistance to leaving marks from the leg gathers is sometimes referred to as "mark-removal resistance").

[0014] Furthermore, the disposable diaper has leakage resistance equivalent to or greater than that of the conventional disposable diapers described above in which the multiple thread-like elastic members constituting the leg gathers have the same contractile force (hereinafter, leakage resistance may be referred to as "leak prevention"). As described above, the disposable diaper has excellent leg passageability and provides a sense of security when put on, and has excellent mark-removal resistance and leakage resistance when put on.

[0015] [Aspect 2] The disposable diaper according to Aspect 1, wherein in the unfolded state, at intersections where an area centered on the widthwise centerline and occupying 10% of the longitudinal length of the disposable diaper intersects with each of the pair of leg gathered portions, a first distance in the first area is longer than a second distance in the second area.

[0016] In the disposable diaper, the first distance in the first region is longer than the second distance in the second region at a given intersection, so that the disposable diaper has excellent leg passageability and a sense of security when worn, and is also excellent in mark-removal resistance and leak resistance during wear.

[0017] [Aspect 3] The disposable diaper according to Aspect 1 or 2, wherein the first distance is 5.0 to 12 mm in the unfolded state and at the intersection. In the disposable diaper, the first distance has a predetermined length. Therefore, the disposable diaper has excellent leg passageability and a sense of security when put on, and is excellent in mark-removal resistance and leak resistance during wear.

[0018] [Aspect 4] The disposable diaper according to any one of Aspects 1 to 3, wherein the first distance is 1.2 to 2.0 times longer than the second distance in the unfolded state and at the intersection. In the disposable diaper, the first distance and the second distance have a predetermined relationship. Therefore, the disposable diaper has excellent leg passageability and a sense of security when put on, and is excellent in mark-removal resistance and leak resistance during wear.

[0019] [Aspect 5] The disposable diaper according to any one of Aspects 1 to 4, wherein in the unfolded state, the first thread-like elastic member is fixed to the fabric in a state in which the first thread-like elastic member has the smallest elastic force among the plurality of thread-like elastic members.

[0020] In the disposable diaper, the first thread-like elastic members are fixed to the fabric in a predetermined state, and therefore the disposable diaper has excellent leg passageability and a sense of security when put on, and is excellent in mark-removal resistance and leakage resistance during wear.

[0021] [Aspect 6] The disposable diaper according to any one of Aspects 1 to 5, wherein in the unfolded state, the disposable diaper further comprises an absorbent main body having the pair of leg gathers and an absorber, the plurality of thread-like elastic members further comprising an innermost thread-like elastic member disposed innermost in the width direction among the plurality of thread-like elastic members, and in the unfolded state, the innermost thread-like elastic member is fixed to the fabric in a state in which it has the highest elastic force among the plurality of thread-like elastic members.

[0022] In the disposable diaper, the innermost thread-like elastic member is fixed to the fabric in a state where it has the highest elastic force among the plurality of thread-like elastic members, which allows the absorbent body to fit the wearer's body more easily and provides excellent leak prevention.

[0023] Aspect 7: The disposable diaper according to any one of Aspects 1 to 6, wherein in the unfolded state, the disposable diaper further comprises an absorbent main body having the pair of leg gathers and an absorber, the plurality of thread-like elastic members further comprising an innermost thread-like elastic member disposed innermost in the width direction among the plurality of thread-like elastic members, and when, in the unfolded state, each of the pair of leg gathers is equally divided between a first thread-like elastic member and the innermost thread-like elastic member into a 1 / 2 region from the first thread-like elastic member and a 2 / 2 region from the innermost thread-like elastic member, the sum of the elastic forces of the thread-like elastic members present in the 1 / 2 region among the plurality of thread-like elastic members at the intersection is smaller than the sum of the elastic forces of the thread-like elastic members present in the 2 / 2 region among the plurality of thread-like elastic members.

[0024] In the disposable diaper, the total elastic force of the plurality of thread-like elastic members present in the first half region is smaller than the total elastic force of the plurality of thread-like elastic members present in the second half region. That is, the elastic force of the outer side of each of the pair of leg gathers is smaller than the elastic force of the inner side. Therefore, the disposable diaper has excellent leg passageability and a sense of security when put on, and is excellent in mark-removal resistance and leak resistance while being put on.

[0025] Aspect 8 The disposable diaper according to any one of Aspects 1 to 7, wherein in the unfolded state, the disposable diaper further comprises an absorbent main body having the pair of leg gathers and an absorber, the plurality of thread-like elastic members further comprising an innermost thread-like elastic member among the plurality of thread-like elastic members, the innermost thread-like elastic member being disposed innermost in the width direction, and when, in the unfolded state, each of the pair of leg gathers is divided into thirds, between a first thread-like elastic member and the innermost thread-like elastic member, in order from the first thread-like elastic member side, into a 1 / 3 region, a 2 / 3 region, and a 3 / 3 region, at the intersection, the sum of the elastic forces of the thread-like elastic members present in the 1 / 3 region among the plurality of thread-like elastic members is smaller than the sum of the elastic forces of the thread-like elastic members present in the 3 / 3 region among the plurality of thread-like elastic members.

[0026] In the disposable diaper, the total elastic force of the plurality of thread-like elastic members present in the first third region is smaller than the total elastic force of the plurality of thread-like elastic members present in the third third region. That is, the elastic force of the outer side of each of the pair of leg gathers is smaller than the elastic force of the inner side. Therefore, the disposable diaper has excellent leg passageability and a sense of security when put on, and is excellent in mark-removal resistance and leak resistance while being put on.

[0027] Aspect 9 The disposable diaper according to any one of Aspects 1 to 8, wherein in the unfolded state, the disposable diaper further comprises an absorber disposed between the pair of leg gathers, and the plurality of thread-like elastic members further comprises an innermost thread-like elastic member disposed innermost in the width direction among the plurality of thread-like elastic members, and when, in the unfolded state, each of the pair of leg gathers is divided into four equal parts, between a first thread-like elastic member and the innermost thread-like elastic member, into a 1 / 4 region, a 2 / 4 region, a 3 / 4 region, and a 4 / 4 region, in that order from the first thread-like elastic member side, at the intersection, the sum of the elastic forces of the thread-like elastic members present in the 1 / 4 region among the plurality of thread-like elastic members is smaller than the sum of the elastic forces of the thread-like elastic members present in the 4 / 4 region among the plurality of thread-like elastic members.

[0028] In the disposable diaper, the total elastic force of the plurality of thread-like elastic members present in the 1 / 4 region is smaller than the total elastic force of the plurality of thread-like elastic members present in the 4 / 4 region. That is, the elastic force of the outer side of each of the pair of leg gathers is smaller than the elastic force of the inner side. Therefore, the disposable diaper has excellent leg passageability and a sense of security when put on, and is excellent in mark-removal resistance and leak resistance while being put on.

[0029] [Aspect 10] The disposable diaper according to any one of Aspects 1 to 9, wherein, in the unfolded state and at the crossing portion, each of the pair of leg gathered portions includes an additional inelastic material in the entire second region but does not include an additional inelastic material in a portion of the first region.

[0030] In the disposable diaper described above, each of the pair of leg gathers has, in the unfolded state, an additional inelastic material in the entire second region but no additional inelastic material in a portion of the first region. Therefore, the stiffness of the first region of each of the pair of leg gathers is lower than the stiffness of the second region of each of the pair of leg gathers, making it relatively easy to form ruffles in the first region and relatively difficult to form ruffles in the second region. As a result, the first region has excellent frill formation properties, and the second region has excellent leak-proofing properties.

[0031] [Aspect 11] The disposable diaper according to any one of aspects 1 to 10, wherein, in the disposable diaper laid flat, the number of pleats in the first region is less than the number of pleats in the second region.

[0032] In the disposable diaper, the number of pleats in the first region is smaller than the number of pleats in the second region, i.e., the size of the pleats in the first region is larger than the size of the pleats in the second region. The disposable diaper has excellent leg passage and comfort when donned, and is excellent in mark resistance and leak resistance during donning. Furthermore, the pleats in the first region are in contact with the wearer's legs, and the large pleats in the first region provide a feeling of softness to the wearer's legs.

[0033] [Aspect 12] The disposable diaper according to any one of Aspects 1 to 11, wherein the plurality of thread-like elastic members further includes a third thread-like elastic member adjacent to the second thread-like elastic member on the side opposite to the first thread-like elastic member, and where a region defined by the second thread-like elastic member and the third thread-like elastic member is defined as a third region, at the intersection in the unfolded state, a second distance of the second region is longer than a third distance, which is the width of the third region in the width direction.

[0034] The disposable diaper is configured such that the second distance in the second region is longer than the third distance in the crossing portion. As a result, in the disposable diaper, the first region is less likely to contract than the second region and the second region is less likely to contract than the third region in its natural state, which facilitates the reliable formation of frills along the widthwise outer edges of the leg gathers and provides excellent frill formability. As a result, the disposable diaper has excellent leg passageability and comfort when put on, and is excellent in mark-removal resistance and leak resistance during wear.

[0035] [Aspect 13] The disposable diaper according to aspect 12, wherein, in the disposable diaper laid flat, the number of pleats in the first region is less than the number of pleats in the second region, and the number of pleats in the second region is less than the number of pleats in the third region.

[0036] In the disposable diaper, the number of pleats in the first region is smaller than the number of pleats in the second region, and the number of pleats in the second region is smaller than the number of pleats in the third region. That is, the size of the pleats in the first region is larger than the size of the pleats in the second region, and the size of the pleats in the second region is larger than the size of the pleats in the third region. Therefore, the disposable diaper has excellent leg passageability and a sense of security when put on, and has excellent mark-removal resistance and is leak-resistant during wear. Furthermore, the pleats in the first region are in contact with the wearer's legs, and the large pleats in the first region provide a feeling of softness to the wearer's legs.

[0037] [Aspect 14] When the disposable diaper is laid flat with the waist opening facing upward and the pair of leg openings facing left and right, the disposable diaper has a vertical direction and a horizontal direction corresponding to the longitudinal direction and the width direction, respectively, and the disposable diaper has a vertical centerline extending parallel to the vertical direction at the center in the horizontal direction, a horizontal bottom line at the lowermost part of the vertical direction and perpendicular to the vertical centerline, and an intersection point of the vertical centerline and the horizontal bottom line, where an upper angle UA (°) formed by an upper line and a horizontal bottom line passing through the intersection point and passing the uppermost and outermost positions of the pair of leg openings and an upper angle LA (°) formed by a lower line and a horizontal bottom line passing through the intersection point and passing the lowermost and outermost positions of the pair of leg openings, the upper angle UA (°) and the lower angle LA (°) can be expressed by the following formula: Aspect 14. The disposable diaper according to any one of aspects 1 to 13, wherein 20<UA-LA is satisfied.

[0038] In the above disposable diaper, the upper angle: UA (°) and the lower angle: LA (°) satisfy a specified relationship, so the width of the leg openings is widened, making it easier for the wearer to put their legs through the leg openings, and the disposable diaper has excellent leg passageability.

[0039] [Aspect 15] In a flat state in which the disposable diaper is placed with the waist opening facing upward and the pair of leg openings facing left and right, the disposable diaper has a vertical direction and a horizontal direction corresponding to the longitudinal direction and the width direction, respectively, and the disposable diaper has a vertical centerline extending parallel to the vertical direction at the center in the horizontal direction, a horizontal bottom line at the lowermost part of the vertical direction and perpendicular to the vertical centerline, and an intersection point of the vertical centerline and the horizontal bottom line, where an upper angle UA (°) formed by an upper line and a horizontal bottom line passing through the intersection point and passing the uppermost and outermost positions of the pair of leg openings and a lower angle LA (°) formed by a lower line and a horizontal bottom line passing through the intersection point and passing the lowermost and outermost positions of the pair of leg openings, the upper angle UA (°) and the lower angle LA (°) are determined by the following formula: 2×LA<UA Aspect 15. The disposable diaper according to any one of aspects 1 to 14, wherein

[0040] In the above disposable diaper, the upper angle: UA (°) and the lower angle: LA (°) satisfy a specified relationship, so the width of the leg openings is widened, making it easier for the wearer to put their legs through the leg openings, and the disposable diaper has excellent leg passageability.

[0041] Disposable diapers according to the present disclosure will be described in detail below. Figures 1 to 9 are diagrams showing a disposable diaper 1 according to one embodiment of the present disclosure (hereinafter referred to as the "first embodiment"). Figure 1 is a perspective view of the disposable diaper 1. Figure 2 is a plan view of the disposable diaper 1 in an unfolded state. Figure 3 is an end view taken along the widthwise centerline CW in Figure 2. Figures 4 to 7 are each an enlarged partial view of Figure 3. Figure 8 is a plan view of the disposable diaper 1 in a flat state. Figure 9 is a diagram showing the disposable diaper 1 being worn by a wearer.

[0042] When unfolded, the disposable diaper 1 has a longitudinal direction L, a width direction W, and a thickness direction T that are perpendicular to each other, and has a longitudinal center line CL that passes through the center of the width direction W and extends along the longitudinal direction L, and a width center line CW that passes through the center of the longitudinal direction L and extends along the width direction W.

[0043] The disposable diaper 1 comprises a ventral section 3, a dorsal section 5, and a crotch section 7 located between the ventral section 3 and the dorsal section 5. The ventral section 3 is the section of the disposable diaper 1 that covers the ventral side of the wearer. The crotch section 7 is the section of the disposable diaper 1 that covers the crotch area of ​​the wearer and is composed of an absorbent main body 8. The dorsal section 5 is the section of the disposable diaper 1 that covers the dorsal side of the wearer. The front and rear ends of the absorbent main body 8 in the longitudinal direction L are connected to the central portions of the ventral section 3 and the dorsal section 5 in the width direction W, respectively, using a hot melt adhesive.

[0044] In the disposable diaper 1, a pair of ventral-side joining portions 3a located at both ends in the width direction W of the ventral-side portion 3 and a pair of dorsal-side joining portions 5a located at both ends in the width direction W of the dorsal-side portion 5 are joined together to form a pair of side joining portions 11. As a result, in the disposable diaper 1, the ventral-side portion 3 and the dorsal-side portion 5 joined together at the pair of side joining portions 11 form a waist portion WP that covers the waist of the wearer and has waist gathers. Furthermore, a waist opening WH through which the wearer's waist passes is defined by the outer ends in the longitudinal direction L of the ventral-side portion 3 and the dorsal-side portion 5. Furthermore, in the disposable diaper 1, a pair of leg openings LH through which the wearer's legs pass is defined by the opposite ends in the width direction W of the absorbent main body 8 and the inner ends in the longitudinal direction L of the ventral-side portion 3 and the dorsal-side portion 5.

[0045] In the unfolded state, the abdominal portion 3 and the back portion 5 each have a rectangular shape that is elongated in the width direction W, and are spaced apart from each other in the longitudinal direction L. The absorbent main body 8 has a rectangular shape that is elongated in the longitudinal direction L, and one end in the longitudinal direction L is connected to the abdominal portion 3, and the other end is connected to the back portion 5. The abdominal portion 3, the absorbent main body 8, and the back portion 5 are formed separately from each other.

[0046] The ventral portion 3 and the back portion 5 are each formed from a liquid-impermeable sheet material. Each of the ventral portion 3 and the back portion 5 is formed by stacking at least a sheet material located on the skin side and a sheet material located on the non-skin side in the thickness direction T and joining them with an adhesive, heat sealing, or the like (the same applies below). The outer end of the sheet material located on the non-skin side in the longitudinal direction L is folded back toward the skin side. In this case, the non-skin side sheet material at the folded position in each of the ventral portion 3 and the back portion 5 constitutes the end of the ventral portion 3 and the back portion 5 in the longitudinal direction L, respectively.

[0047] The abdominal portion 3 is provided with a plurality of waist-surrounding elastic members 13 for waist gathering between a sheet member located on the skin side and a sheet member located on the non-skin side. The plurality of waist-surrounding elastic members 13 extend from one end to the other end in the width direction W of the abdominal portion 3, except for an area overlapping with the center of the absorbent body 9 in the thickness direction T, and are arranged at intervals in the longitudinal direction L. The skin-side and non-skin-side sheet members and the plurality of waist-surrounding elastic members 13 are joined with an adhesive or the like.

[0048] The back portion 5 also has a plurality of waist elastic members 14 for waist gathering between the sheet member located on the skin side and the sheet member located on the non-skin side. The plurality of waist elastic members 14 extend from one end to the other end in the width direction W of the back portion 5, except for the region overlapping with the center of the absorbent body 9 in the thickness direction T, and are arranged at intervals in the longitudinal direction L. The skin-side and non-skin-side sheet members and the plurality of waist elastic members 14 are joined with an adhesive or the like.

[0049] In the first embodiment, the disposable diaper 1 further includes an exterior sheet member 15 bridging the gap between the ventral portion 3 and the dorsal portion 5. The exterior sheet member 15 is a liquid-impermeable sheet member, such as a nonwoven fabric, and both ends in the longitudinal direction L are laminated to the ventral portion 3 and the dorsal portion 5, respectively, and joined thereto with an adhesive or the like. The exterior sheet member 15 is also joined with an adhesive or the like to the non-skin side of the absorbent main body 8, which is disposed generally between the ventral portion 3 and the dorsal portion 5, to protect the absorbent main body 8 from the non-skin side.

[0050] The absorbent main body 8 comprises a main body central portion 21 located in the center in the width direction W and extending in the longitudinal direction L, and a pair of leg gather portions 23 located at both ends in the width direction W. The main body central portion 21 has a substantially rectangular shape and includes a liquid-permeable top sheet 25, a liquid-impermeable back sheet 27, and an absorbent body 9 located between the top sheet 25 and the back sheet 27 and absorbing and retaining liquid. The absorbent body 9 is joined to the top sheet 25 and the back sheet 27 with an adhesive. The top sheet 25 and the back sheet 27 are joined at their peripheral portions with an adhesive. The absorbent body 9 includes an absorbent core 9b that absorbs and retains liquid, a core wrap 9a that contains the absorbent core 9b, and groove portions 9c that can diffuse liquid in the longitudinal direction L and the width direction W.

[0051] The main body central portion 21 is provided with a pair of leak-proof walls 29 arranged on both sides in the width direction W facing each other and extending along the longitudinal direction L. The leak-proof walls 29 extend along the longitudinal direction L and are formed of a sheet member 29b containing a plurality of leak-proof elastic members 29a arranged at intervals in the width direction W. The leak-proof walls 29 have their outer ends in the width direction W joined to at least one of the top sheet 25, absorbent body 9, and back sheet 27 with an adhesive or the like to form fixed ends, and their inner ends in the width direction W are separated from the other sheets, including the top sheet 25, to form free ends. The plurality of leak-proof elastic members 29a are joined with an adhesive to the vicinity of the free ends of the sheet member 29b.

[0052] The pair of leg gathers 23 are joined to both ends of the main body central portion 21 in the width direction W. Each of the pair of leg gathers 23 extends along the longitudinal direction L and includes a plurality of thread-like elastic members 31 arranged at intervals in the width direction W, and a nonwoven fabric sheet 33 that sandwiches the thread-like elastic members 31 from the skin side and non-skin side. Each of the pair of leg gathers 23 has an inner end in the width direction W joined with an adhesive or the like to the non-skin side surface of the end in the width direction W of the main body central portion 21 as a fixed end, and an outer end in the width direction W as a free end spaced apart from the main body central portion 21. The thread-like elastic members 31 are joined with an adhesive near the free ends of the skin side and non-skin side nonwoven fabric sheet 33. The thread-like elastic members 31 allow the leg gathers 23 to stretch.

[0053] In the disposable diaper 1, the pair of leg gathers 23 are bridged by an exterior sheet member 15. The exterior sheet member 15 has both ends in the width direction W laminated to the pair of leg gathers 23 and joined with an adhesive or the like, thereby protecting the pair of leg gathers 23 from the non-skin side.

[0054] The pair of leg gathers 23 form a pair of leg openings LH in the crotch portion 7 of the disposable diaper 1 and are stretchable in the longitudinal direction L. Each of the pair of leg gathers 23 includes a nonwoven fabric sheet 33 having a widthwise outer edge 37 located at the outermost side in the widthwise direction W, a plurality of thread-like elastic members 31 fixed to the nonwoven fabric sheet 33 so as to extend in the longitudinal direction L on a side inward in the widthwise direction W from the widthwise outer edge 37, and a film sheet 35 which is an additional inelastic material.

[0055] Specifically, nonwoven fabric sheet 33 is divided by a folding line (not shown) into a skin-side nonwoven fabric sheet 33a and a non-skin-side nonwoven fabric sheet 33b, and is bonded with an adhesive between a film sheet 35 arranged relatively closer to the skin and a plurality of thread-like elastic members 31 arranged relatively closer to the skin, with the thread-like elastic members 31 fixed to film sheet 35 and non-skin-side nonwoven fabric sheet 33b. The folding line forms outer edge 37 in the width direction.

[0056] The multiple thread-like elastic members 31 are configured, in order from the outer edge toward the inside in the width direction, as a first thread-like elastic member 31 a, a second thread-like elastic member 31 b, a third thread-like elastic member 31 c, a fourth thread-like elastic member 31 d, and a fifth thread-like elastic member 31 e. The fifth thread-like elastic member 31 e corresponds to the innermost thread-like elastic member disposed at the innermost side in the width direction W.

[0057] The area defined by the widthwise outer edge 37 and the first thread-shaped elastic member 31a is referred to as the first area 41, the area defined by the first thread-shaped elastic member 31a and the second thread-shaped elastic member 31b is referred to as the second area 43, and the area defined by the second thread-shaped elastic member 31b and the third thread-shaped elastic member 31c is referred to as the third area 45.

[0058] In the unfolded state and throughout the crotch region 7, a first distance 41D corresponding to the width of the first region 41 in the width direction W is longer than a second distance 43D corresponding to the width of the second region 43 in the width direction W. This allows the disposable diaper 1 to have excellent leg passage and a sense of security when put on, and to have excellent marking resistance and low leakage during wear. Furthermore, in the unfolded state and throughout the crotch region 7, the first distance is 8 mm. This allows the disposable diaper 1 to have excellent leg passage and a sense of security when put on, and to have excellent marking resistance and low leakage during wear.

[0059] In the unfolded state and throughout the crotch region 7, the second distance 43D of the second region 43 is longer than the third distance 45D corresponding to the width of the third region 45 in the width direction W. This allows the disposable diaper 1 to have excellent leg passageability and a sense of security when put on, and also has excellent mark-removal resistance and is less likely to leak while being put on.

[0060] The first thread-like elastic member 31a is made of rubber of the same composition as the second thread-like elastic members 31b to the fifth thread-like elastic members 31e, and is fixed to the nonwoven fabric sheet 33 (specifically, the non-skin-side nonwoven fabric sheet 33b) at the same stretch ratio in the expanded state, but has the smallest diameter. The second thread-like elastic members 31b to the fifth thread-like elastic members 31e all have the same diameter.

[0061] Therefore, in the unfolded state, the first thread-like elastic member 31a is directly fixed with adhesive to the nonwoven fabric sheet 33 (specifically, the non-skin-side nonwoven fabric sheet 33b) in a state where it has the smallest elastic force among the plurality of thread-like elastic members 31. This allows the disposable diaper 1 to have excellent leg passageability and a sense of security when put on, and also has excellent mark-removal resistance and is less likely to leak while being put on.

[0062] In addition, in the deployed state, the fifth thread-like elastic member 31e (the innermost thread-like elastic member) is directly fixed with adhesive to the nonwoven fabric sheet 33 (specifically, the non-skin-side nonwoven fabric sheet 33b) in a state where it has the highest elastic force among the multiple thread-like elastic members 31. This allows the absorbent body 9 to fit the wearer's body more easily, resulting in excellent leak prevention properties.

[0063] Each of the pair of leg gathered portions 23 can be divided between the first thread-like elastic member 31a and the fifth thread-like elastic member 31e (the innermost thread-like elastic member) into a 1 / 2 region 51 from the first thread-like elastic member and a 2 / 2 region 53 from the fifth thread-like elastic member 31e (the innermost thread-like elastic member).

[0064] In this case, in the unfolded state and throughout the entire crotch region 7, the sum of the elastic forces of the first and second thread-like elastic members 31a, 31b present in the first / second region 51 is smaller than the sum of the elastic forces of the third, fourth, and fifth thread-like elastic members 31c, 31d, 31e present in the second / second region 53. As a result, the elastic force of the outer side of each of the pair of leg gathers 23 is smaller than the elastic force of the inner side. As a result, the disposable diaper 1 has excellent leg passageability and comfort when put on, and is excellent in terms of resistance to leaving marks and resistance to leakage during wear.

[0065] Each of the pair of leg gathered portions 23 can be divided into three equal parts, between the first thread-like elastic member 31a and the fifth thread-like elastic member 31e (the innermost thread-like elastic member), in order from the first thread-like elastic member 31a side: a first / third region 55, a second / third region 57, and a third / third region 59. The center line of the second thread-like elastic member 31b exists at the boundary between the first / third region 55 and the second / third region 57.

[0066] In this case, in the unfolded state and throughout the entire crotch region 7, the sum of the elastic forces of the first thread-like elastic members 31a (100%) and the second thread-like elastic members 31b (50%) present in the first-third region 55 is smaller than the sum of the elastic forces of the fourth thread-like elastic members 31d and the fifth thread-like elastic members 31e present in the third-third region 59. As a result, the elastic force of the outer side of each of the pair of leg gathers 23 is smaller than the elastic force of the inner side. As a result, the disposable diaper 1 has excellent leg passageability and comfort when put on, and is excellent in mark-removal resistance and leak resistance during wear.

[0067] Each of the pair of leg gathered portions 23 can be divided into four equal parts, namely, a first / quarter region 61, a second / quarter region 63, a third / quarter region 65, and a fourth / quarter region 67, between the first thread-like elastic member 31a and the fifth thread-like elastic member 31e (the innermost thread-like elastic member), in order from the first thread-like elastic member 31a side.

[0068] In this case, in the unfolded state and throughout the entire crotch region 7, the elastic force of the first thread-like elastic member 31a present in the 1 / 4 region 61 is smaller than the sum of the elastic forces of the fourth thread-like elastic member 31d and the fifth thread-like elastic member 31e present in the 4 / 4 region 67. As a result, the elastic force of the outer side of each of the pair of leg gathers 23 is smaller than the elastic force of the inner side. As a result, the disposable diaper 1 has excellent leg passageability and comfort when put on, and is excellent in mark-removal resistance and leakage resistance during wear.

[0069] Each of the pair of leg gathered portions 23 is provided with a film sheet 35, which is an additional inelastic material, in an area overlapping with the first thread-like elastic member 31a and the fifth thread-like elastic member 31e (the innermost thread-like elastic member) in the thickness direction T, but is not provided with the film sheet 35, which is an additional inelastic material, in a part of the first region 41, particularly in the widthwise outer edge 37. This provides the first region with excellent frill forming properties and the second region with excellent leak-proofing properties.

[0070] 8, in the disposable diaper 1 when laid flat, the number of pleats in the first region 41 is less than the number of pleats in the second region 43, which in turn is less than the number of pleats in the third region 45. This allows the disposable diaper 1 to have excellent leg passage and a sense of security when put on, and also has excellent mark-removal resistance and is less prone to leakage during wear.

[0071] When the disposable diaper 1 is laid flat with the waist opening WH facing upward and the pair of leg openings LH facing left and right, the disposable diaper 1 has a longitudinal direction Y and a lateral direction X corresponding to the longitudinal direction L and width direction W, respectively. The disposable diaper 1 also has a longitudinal centerline CY extending parallel to the longitudinal direction Y at the center of the lateral direction X, a lateral bottomline CX perpendicular to the longitudinal centerline CY at the bottom of the longitudinal direction Y, and an intersection 71 of the longitudinal centerline CY and the lateral bottomline CX.

[0072] Furthermore, the upper angle formed by the upper line UL and the lateral bottom line CX, which pass through the intersection point 71 and pass through the uppermost and outermost positions of each of the pair of leg openings LH, is defined as UA (°), and the lower angle formed by the lower line LL and the lateral bottom line CX, which pass through the intersection point 71 and pass through the lowermost and outermost positions of each of the pair of leg openings LH, is defined as LA (°).

[0073] The disposable diaper 1 according to the first embodiment satisfies the following formula: 20<UA-LA, which allows the disposable diaper 1 to have excellent leg passageability.

[0074] Furthermore, the disposable diaper 1 according to the first embodiment satisfies the following formula: 2×LA<UA, which provides the disposable diaper 1 with excellent leg passageability.

[0075] The disposable diaper according to the present disclosure has, in an unfolded state, longitudinal, width, and thickness directions that are perpendicular to one another, and comprises a ventral portion, a dorsal portion, and a crotch portion between the ventral and dorsal portions, and both side edges in the width direction of the ventral portion and both side edges in the width direction of the dorsal portion are connected to define a waist opening and a pair of leg openings.

[0076] The disposable diaper may be a so-called three-piece type disposable diaper as shown in the first embodiment, or may be a so-called two-piece type disposable diaper. The disposable diaper may be for children or for adults. A so-called two-piece type disposable diaper is a disposable diaper that, in an unfolded state, has a ventral section, a dorsal section, and a crotch section between the ventral section and the dorsal section, and the crotch section is joined to the ventral section and the dorsal section by a single outer cover. The disposable diaper may be a pants-type disposable diaper in which both widthwise sides of the ventral section and both widthwise sides of the dorsal section are already joined by side joints, or may be a tape-type disposable diaper in which both widthwise sides of the ventral section and both widthwise sides of the dorsal section are joined by, for example, a tape member when put on the diaper.

[0077] The disposable diaper generally further includes an absorbent body, which may be an absorbent main body including a pair of leg gathers and the absorbent body, as described below.

[0078] In an unfolded state, the disposable diaper may have a longitudinal centerline extending parallel to the longitudinal direction at the center of the width of the disposable diaper, and a widthwise centerline extending parallel to the width of the disposable diaper at the center of the length of the disposable diaper. In this specification, the "unfolded state" refers to a state in which the disposable diaper is unfolded on a plane by releasing the side seams of the disposable diaper to separate the ventral and dorsal sections, and stretching the disposable diaper's constituent materials (e.g., nonwoven fabrics) without breaking them. In this specification, the unfolded state of the disposable diaper may also be referred to simply as the "unfolded state."

[0079] In this specification, the side relatively closer to the longitudinal centerline may be referred to as the "inner side," and the side relatively farther from the longitudinal centerline may be referred to as the "outer side." The same applies to the vertical centerline. In this specification, in terms of the thickness direction, the side relatively closer to the wearer's skin when worn may be referred to as the "skin side," and the side relatively farther from the wearer's skin when worn may be referred to as the "non-skin side."

[0080] The disposable diaper according to the present disclosure includes a pair of leg gathers at the crotch portion, which define the pair of leg openings and are stretchable in the longitudinal direction. Each of the pair of leg gathers includes a fabric having a widthwise outer edge located at the outermost position in the width direction, and a plurality of thread-like elastic members fixed directly or indirectly to the fabric so as to extend in the longitudinal direction on a position inside the widthwise outer edge. Preferably, each of the plurality of thread-like elastic members is spaced apart in the width direction. Each of the pair of leg gathers may also include an additional material, such as a non-elastic material.

[0081] Examples of each of the multiple thread-like elastic members include rubber threads, such as round and flat elastic members. Examples of the fabric include nonwoven fabrics, woven fabrics, and textiles. Examples of the additional inelastic materials include the fabrics and films described above. It is preferable that the multiple thread-like elastic members are covered with a material on at least one of their skin side and non-skin side, and it is more preferable that they are covered with a material on both their skin side and non-skin side. Examples of such materials include the fabrics and additional inelastic materials. The outer widthwise edge refers to the outermost portion of the fabric in the widthwise direction, and can be, for example, a fold line of the fabric that directly or indirectly covers the multiple thread-like elastic members from the skin side and non-skin side.

[0082] In the unfolded state, each of the plurality of thread-like elastic members in each of the pair of leg gathered portions may be arranged parallel to the longitudinal direction, or may be arranged non-parallel to the longitudinal direction, for example, in a direction along the longitudinal direction.

[0083] When the plurality of thread-like elastic members is composed of n thread-like elastic members, the nth thread-like elastic member from the outer edge in the width direction can be referred to as the nth thread-like elastic member. For example, the second thread-like elastic member from the outer edge in the width direction can be referred to as the second thread-like elastic member. Furthermore, the nth thread-like elastic member, which is the innermost thread-like elastic member in the width direction among the plurality of thread-like elastic members, can be referred to as the innermost thread-like elastic member.

[0084] When the plurality of thread-like elastic members is composed of n thread-like elastic members, the region defined by the widthwise outer edge and the first thread-like elastic member is referred to as the first region, and the region defined by the (n-1)th thread-like elastic member and the nth thread-like elastic member is referred to as the nth region. For example, the region defined by the first thread-like elastic member and the second thread-like elastic member is referred to as the second region. For example, when n=5, there are up to a fifth region. Furthermore, the width (length) in the width direction of the nth region is referred to as the nth distance.

[0085] The n in each of the pair of leg gathered portions is not particularly limited, but is a natural number of 2 or more, preferably 2 or more, more preferably 4 or more, and preferably 10 or less, more preferably 8 or less. This makes it easier to achieve the effects of the present disclosure. Also, each of the pair of leg gathered portions easily fits the wearer's leg as a whole.

[0086] In the disposable diaper in the unfolded state according to the present disclosure, at the intersections where the widthwise centerline and each of the pair of leg gathers intersect, the first distance in the first region is longer than the second distance in the second region, thereby providing the disposable diaper with excellent leg passageability and a sense of security when put on, and with excellent mark-removal resistance and leakage resistance during wear.

[0087] In the disposable diaper according to the present disclosure, the intersecting portions are preferably not only the regions where the widthwise centerline intersects with each of the pair of leg gathers, but also regions where the pair of leg gathers intersect with a region that, in the unfolded state, is centered on the widthwise centerline and occupies preferably 10%, more preferably 20%, even more preferably 30%, and even more preferably 40% of the longitudinal length of the disposable diaper. This allows the disposable diaper to have excellent leg passage and a sense of security when put on, and to have excellent mark-removal resistance and low leakage resistance during wear. In this case, the relationship between the first distance and the second distance is satisfied at any point where the intersecting portion intersects with a line parallel to the widthwise centerline.

[0088] In the disposable diaper according to the present disclosure, when n is 3 or greater, it is preferable that the second distance in the second region be longer than the third distance in the third region at the intersections of the widthwise centerline and each of the pair of leg gathers, thereby providing the disposable diaper with excellent leg passageability and a sense of security when donned, and with excellent mark-removal resistance and low leakage resistance during donning.

[0089] Furthermore, in the disposable diaper according to the present disclosure, when n is 3 or greater, the intersections are preferably not only the regions where the widthwise centerline intersects with each of the pair of leg gathers, but also the regions where each of the pair of leg gathers intersects with a region that, in the unfolded state, is centered on the widthwise centerline and occupies preferably 10%, more preferably 20%, even more preferably 30%, and even more preferably 40% of the longitudinal length of the disposable diaper. This allows the disposable diaper to have excellent leg passage and a sense of security when put on, and to have excellent mark-removal resistance and low leakage resistance during wear. In this case, the relationships among the first distance, the second distance, and the third distance are satisfied at any point where the intersections intersect with a line parallel to the widthwise centerline.

[0090] In the disposable diaper in an unfolded state according to the present disclosure, at the intersections where the widthwise centerline and each of the pair of leg gathers intersect, the first distance is preferably 5 mm or more, more preferably 6 mm or more, and even more preferably 7 mm, and the first distance is preferably 12 mm or less, more preferably 11 mm or less, and even more preferably 10 mm or less, thereby providing the disposable diaper with excellent leg passageability and a sense of security when put on, excellent mark-removal resistance, and low leakage resistance during wear.

[0091] In the disposable diaper according to the present disclosure, the intersecting portions are preferably not only the regions where the widthwise centerline intersects with each of the pair of leg gathers, but also regions where the pair of leg gathers intersect with a region that, in the unfolded state, is centered on the widthwise centerline and occupies preferably 10%, more preferably 20%, even more preferably 30%, and even more preferably 40% of the longitudinal length of the disposable diaper. This allows the disposable diaper to have excellent leg passage and a sense of security when put on, and to have excellent mark-removal resistance and low leakage during wear. In this case, the length of the first distance is satisfied at any point where the intersecting portion intersects with a line parallel to the widthwise centerline.

[0092] In the disposable diaper in an unfolded state according to the present disclosure, at the intersections where the widthwise centerline and each of the pair of leg gathered portions intersect, the first distance is longer than the second distance by preferably at least 1.10 times, more preferably at least 1.15 times, and even more preferably at least 1.20 times, and the first distance is longer than the second distance by preferably not more than 6.0 times, more preferably not more than 2.5 times, and even more preferably not more than 1.8 times, thereby providing the disposable diaper with excellent leg passageability and security during donning, excellent mark-removal resistance, and low leakage resistance during donning.

[0093] In the disposable diaper according to the present disclosure, the intersecting portions are preferably not only the regions where the widthwise centerline intersects with each of the pair of leg gathers, but also regions where the pair of leg gathers intersect with a region that, in the unfolded state, is centered on the widthwise centerline and occupies preferably 10%, more preferably 20%, even more preferably 30%, and even more preferably 40% of the longitudinal length of the disposable diaper. This allows the disposable diaper to have excellent leg passage and a sense of security when put on, and to have excellent mark-removal resistance and low leakage resistance during wear. In this case, the relationship between the first distance and the second distance is satisfied at any point where the intersecting portion intersects with a line parallel to the widthwise centerline.

[0094] In the disposable diaper according to the present disclosure, when n is 3 or greater, in the unfolded state, and at the intersections where the widthwise centerline and each of the pair of leg gathered portions intersect, the first distance is longer than the third distance by preferably at least 1.2 times, more preferably at least 1.4 times, and even more preferably at least 1.5 times, and the first distance is longer than the third distance by preferably not more than 2.0 times, more preferably not more than 1.8 times, and even more preferably not more than 1.7 times. This allows the disposable diaper to have excellent leg passageability and security when put on, and to have excellent mark-removal resistance and low leakage resistance when put on.

[0095] In the disposable diaper according to the present disclosure, the intersecting portions are preferably not only the regions where the widthwise centerline intersects with each of the pair of leg gathers, but also regions where the pair of leg gathers intersect with a region that, in the unfolded state, is centered on the widthwise centerline and occupies preferably 10%, more preferably 20%, even more preferably 30%, and even more preferably 40% of the longitudinal length of the disposable diaper. This allows the disposable diaper to have excellent leg passage and a sense of security when put on, and to have excellent mark-removal resistance and low leakage during wear. In this case, the relationship between the first distance and the third distance is satisfied at any point where the intersecting portion intersects with a line parallel to the widthwise centerline.

[0096] In the disposable diaper according to the present disclosure, it is preferable that the first thread-like elastic member is fixed directly or indirectly to the fabric in a state where it has the smallest elastic force among the plurality of thread-like elastic members, thereby providing the disposable diaper with excellent leg passageability and a sense of security when donning, excellent mark-removal resistance, and low leakage resistance during donning.

[0097] Furthermore, when the disposable diaper according to the present disclosure includes an absorbent body, it is preferable that the innermost thread-like elastic member be fixed to the fabric in a state where it has the highest elastic strength among the plurality of thread-like elastic members, thereby allowing the absorbent body to better fit the wearer's body and providing excellent leak prevention properties.

[0098] In this specification, the method for measuring the elastic force of each of the multiple thread-like elastic members (the nth thread-like elastic member) is as follows: (1) In a disposable diaper in an unfolded state, mark (two marks in total) on both ends of a predetermined length: L (e.g., 200 mm) of the nth thread-like elastic member. (2) Using a cold spray or the like, remove the nth thread-like elastic member from the disposable diaper. (3) Prepare a tensile tester equipped with two upper and lower chucks. Set the distance between the two upper and lower chucks to 0.5L (e.g., 100 mm). Fix the nth thread-like elastic member to the two upper and lower chucks so that the portion of the nth thread-like elastic member between the two marks is positioned between the two upper and lower chucks. (4) Using a tensile tester, the thread-shaped elastic member in its natural state is stretched at a rate of 100 mm / min until the length between the chucks reaches 0.8 L (e.g., 160 mm), and then the direction is immediately reversed and the member is contracted at a rate of 100 mm / min to 0.5 L (e.g., 100 mm). (5) The tensile strength at 0.8 L (e.g., 160 mm) is read. (6) Using different disposable diapers, steps (1) to (5) are repeated to measure the tensile strength at 10 points, and the average of the measurements is taken as the elastic force of the nth thread-shaped elastic member. An example of such a tensile tester is the Universal Material Tester, Model No. 5565, manufactured by Instron Corporation. The tensile strength at 0.8 L (the tensile strength at 80% elongation relative to the unfolded state) is used as the elastic force, taking into account the actual wearing conditions of disposable diapers.

[0099] The elasticity of the first thread-shaped elastic member is preferably 30% or more, more preferably 40% or more, even more preferably 50% or more, and even more preferably 60% or more of the elasticity of the innermost thread-shaped elastic member. The elasticity of the first thread-shaped elastic member is preferably 90% or less, more preferably 80% or less, even more preferably 75% or less, and even more preferably 70% or less of the elasticity of the innermost thread-shaped elastic member. This provides the disposable diaper with excellent leg passageability and a sense of security when donning, excellent mark-removal resistance, and low leakage resistance during wear. The absorbent core also fits the wearer's body better, resulting in excellent leak prevention. The first thread-shaped elastic member may have an elasticity of, for example, 0.12 to 0.15 N. The innermost thread-shaped elastic member may have an elasticity of, for example, 0.19 to 0.23 N.

[0100] The elastic force of each of the multiple thread-like elastic members (the nth thread-like elastic member) can be adjusted as follows, for example, by illustrating Hooke's Law: F = kx. Note that illustrating Hooke's Law is for the purpose of understanding elastic force, and does not mean that each of the multiple thread-like elastic members according to the present disclosure completely conforms to Hooke's Law.

[0101] The elastic force of the nth thread-shaped elastic member can be adjusted by changing k (spring constant). To change k (spring constant), for example, (i) changing the material constituting the nth thread-shaped elastic member, for example, changing the rubber component constituting the rubber thread, or (ii) changing the cross-sectional area, for example, the diameter, of the nth thread-shaped elastic member can be mentioned. For example, the elastic force of the nth thread-shaped elastic member can be reduced by reducing the diameter of the nth thread-shaped elastic member, and can be increased by increasing the diameter of the nth thread-shaped elastic member.

[0102] The elastic force of the nth thread-like elastic member can be adjusted, for example, by changing x (elongation rate). One way to change x (elongation rate) is to change the stretch ratio when the nth thread-like elastic member is fixed to the fabric. The elastic force of the nth thread-like elastic member can be reduced by, for example, decreasing the stretch ratio when the nth thread-like elastic member is fixed to the fabric, and can be increased by increasing the stretch ratio when the nth thread-like elastic member is fixed to the fabric.

[0103] In the disposable diaper according to the present disclosure, when each of the pair of leg gathers includes an additional inelastic material, it is preferable that each of the pair of leg gathers includes the additional inelastic material throughout the entire second region but does not include the additional inelastic material in part of the first region. It is also more preferable that the first region does not include the inelastic material at the widthwise outer edge. This makes the first region more likely to have excellent ruffle-forming properties and the second region more likely to have excellent leak-proofing properties. When the plurality of thread-like elastic members is composed of n thread-like elastic members, it is preferable that the additional inelastic material be included throughout the entire nth region (n is a natural number greater than or equal to 2). This makes the outer side of each of the pair of leg gathers more likely to have excellent ruffle-forming properties and the inner side more likely to have excellent leak-proofing properties.

[0104] In the disposable diaper according to the present disclosure, in the unfolded state, each of the pair of leg gathers can be equally divided between the first thread-like elastic member and the innermost thread-like elastic member into a first / 2 region closer to the first thread-like elastic member and a second / 2 region closer to the innermost thread-like elastic member. In this case, at the intersection of the widthwise centerline and each of the pair of leg gathers, it is preferable that the sum of the elastic forces of the thread-like elastic members present in the first / 2 region among the plurality of thread-like elastic members is smaller than the sum of the elastic forces of the thread-like elastic members present in the second / 2 region among the plurality of thread-like elastic members. This allows the disposable diaper to have excellent leg passageability and a sense of security when put on, and to have excellent mark-removal resistance and low leakage resistance during wear.

[0105] In this case, the intersecting portions are not limited to the regions where the widthwise centerline intersects with each of the pair of leg gathers, but are preferably regions where the pair of leg gathers intersect with a region that, in the unfolded state, is centered on the widthwise centerline and occupies preferably 10%, more preferably 20%, even more preferably 30%, and even more preferably 40% of the longitudinal length of the disposable diaper. This allows the disposable diaper to have excellent leg passage and security when put on, and also has excellent mark-removal resistance and is less likely to leak during wear. In this case, the relationship of the sum of elastic forces is satisfied at any point where the intersecting portions intersect with a line parallel to the widthwise centerline.

[0106] Furthermore, the total elastic force is calculated assuming that the first thread-like elastic member is located in the 1 / 2 region and that the innermost thread-like elastic member is located in the 2 / 2 region. The other thread-like elastic members are determined based on whether their center lines are located in the 1 / 2 region or the 2 / 2 region. For example, if the center line of the nth thread-like elastic member is located in the 1 / 2 region, the total elastic force is calculated assuming that the nth thread-like elastic member is located in the 1 / 2 region. If the center line of the nth thread-like elastic member is located on the boundary between the 1 / 2 region and the 2 / 2 region, the nth thread-like elastic member is located 50% each in the 1 / 2 region and the elastic force of the nth thread-like elastic member is allocated 50% each to the 1 / 2 region and the 2 / 2 region before the total elastic force is calculated.

[0107] In the disposable diaper according to the present disclosure, in the unfolded state, each of the pair of leg gathers can be divided into three equal parts, in order from the first thread-like elastic member, between the first thread-like elastic member and the innermost thread-like elastic member: a 1 / 3 region, a 2 / 3 region, and a 3 / 3 region. In this case, at the intersections where the widthwise centerline and each of the pair of leg gathers intersect, it is preferable that the sum of the elastic forces of the thread-like elastic members present in the 1 / 3 region among the plurality of thread-like elastic members is smaller than the sum of the elastic forces of the thread-like elastic members present in the 3 / 3 region among the plurality of thread-like elastic members. This allows the disposable diaper to have excellent leg passageability and a sense of security when put on, and to have excellent mark-removal resistance and low leakage resistance during wear.

[0108] In this case, it is preferable that the total elastic force of the plurality of thread-like elastic members present in the first third region is smaller than the total elastic force of the plurality of thread-like elastic members present in the second third region, thereby providing the disposable diaper with excellent leg passageability and security during donning, excellent mark-removal resistance, and low leakage resistance during donning.

[0109] In this case, the intersecting portions are not limited to the regions where the widthwise centerline intersects with each of the pair of leg gathers, but are preferably regions where the pair of leg gathers intersect with a region that, in the unfolded state, is centered on the widthwise centerline and occupies preferably 10%, more preferably 20%, even more preferably 30%, and even more preferably 40% of the longitudinal length of the disposable diaper. This allows the disposable diaper to have excellent leg passage and security when put on, and also has excellent mark-removal resistance and is less likely to leak during wear. In this case, the relationship of the sum of elastic forces is satisfied at any point where the intersecting portions intersect with a line parallel to the widthwise centerline.

[0110] Furthermore, the total elastic force is calculated assuming that the first thread-like elastic member is located in the 1 / 3 region and that the innermost thread-like elastic member is located in the 3 / 3 region. The other thread-like elastic members are determined based on whether their center lines are located in the 1 / 3 region, the 2 / 3 region, or the 3 / 3 region. For example, if the center line of the nth thread-like elastic member is located in the 1 / 3 region, the total elastic force is calculated assuming that the nth thread-like elastic member is located in the 1 / 3 region. Furthermore, if the center line of the nth thread-like elastic member is located on the boundary between the 1 / 3 region and the 2 / 3 region, the nth thread-like elastic member is located 50% each in the 1 / 3 region and the elastic force of the nth thread-like elastic member is allocated 50% each to the 1 / 3 region and the 2 / 3 region before the total elastic force is calculated.

[0111] In the disposable diaper according to the present disclosure, in the unfolded state, each of the pair of leg gathers can be divided into four equal parts, in order from the first thread-like elastic member, between the first thread-like elastic member and the innermost thread-like elastic member: a 1 / 4 region, a 2 / 4 region, a 3 / 4 region, and a 4 / 4 region. In this case, at the intersections where the widthwise centerline and each of the pair of leg gathers intersect, it is preferable that the sum of the elastic forces of the thread-like elastic members present in the 1 / 4 region among the plurality of thread-like elastic members is smaller than the sum of the elastic forces of the thread-like elastic members present in the 4 / 4 region among the plurality of thread-like elastic members. This allows the disposable diaper to have excellent leg passageability and a sense of security when put on, and to have excellent mark-removal resistance and low leakage resistance during wear.

[0112] In this case, the sum of the elastic forces of the plurality of elastic members present in the 1 / 4 region is preferably smaller than the sum of the elastic forces of the plurality of elastic members present in the 2 / 4 region, and is also preferably smaller than the sum of the elastic forces of the plurality of elastic members present in the 3 / 4 region, thereby providing the disposable diaper with excellent leg passageability and security during donning, excellent mark-removal resistance, and low leakage resistance during donning.

[0113] In this case, the intersecting portions are not limited to the regions where the widthwise centerline intersects with each of the pair of leg gathers, but are preferably regions where the pair of leg gathers intersect with a region that, in the unfolded state, is centered on the widthwise centerline and occupies preferably 10%, more preferably 20%, even more preferably 30%, and even more preferably 40% of the longitudinal length of the disposable diaper. This allows the disposable diaper to have excellent leg passage and security when put on, and also has excellent mark-removal resistance and is less likely to leak during wear. In this case, the relationship of the sum of elastic forces is satisfied at any point where the intersecting portions intersect with a line parallel to the widthwise centerline.

[0114] Furthermore, the total elastic force is calculated assuming that the first thread-like elastic member is present in the 1 / 4 region and that the innermost thread-like elastic member is present in the 4 / 4 region. The other thread-like elastic members are determined based on whether their center lines are present in the 1 / 4 region, the 2 / 4 region, the 3 / 4 region, or the 4 / 4 region. For example, if the center line of the nth thread-like elastic member is present in the 1 / 4 region, the total elastic force is calculated assuming that the nth thread-like elastic member is present in the 1 / 4 region. Furthermore, if the center line of the nth thread-like elastic member is present on the boundary between the 1 / 4 region and the 2 / 4 region, the nth thread-like elastic member is considered to be present 50% each in the 1 / 4 region and the second 2 / 4 region, and the total elastic force is calculated after allocating the elastic force of the nth thread-like elastic member 50% each to the 1 / 4 region and the second 2 / 4 region.

[0115] In the disposable diaper according to the present disclosure, when laid flat, the number of pleats in the first region is preferably smaller than the number of pleats in the second region. Furthermore, the above relationship is preferably satisfied in each of the pair of leg gathers. This allows the disposable diaper to have excellent leg passage and a sense of security when worn, and also provides excellent marking resistance and leakage resistance during wear. Furthermore, the large pleats in the first region provide a feeling of softness to the wearer's legs.

[0116] Furthermore, in the disposable diaper according to the present disclosure, when n is 3 or greater, it is preferable that, in the disposable diaper laid flat, the number of pleats in the first region be less than the number of pleats in the second region, which in turn be less than the number of pleats in the third region. This allows the disposable diaper to have excellent leg passage and a sense of security when put on, and to have excellent mark-removal resistance and low leakage during wear. Furthermore, the large pleats in the first region provide a feeling of softness to the wearer's legs.

[0117] In this specification, the term "flat state" in relation to a disposable diaper refers to a state in which the disposable diaper is laid on a flat surface in a natural state without applying any force. The number of pleats can be measured by counting the pleats per unit length (e.g., 10 mm) in a direction parallel to the longitudinal centerline described below. It is preferable to measure the number of pleats for each of a pair of leg gathers and take the average. Furthermore, in measuring the number of pleats, it is preferable to measure the unit length at the intersection.

[0118] When the disposable diaper according to the present disclosure is laid flat with the waist opening facing upward and the pair of leg openings facing left and right, the disposable diaper may have a vertical direction and a horizontal direction corresponding to the longitudinal direction and the width direction, respectively. The disposable diaper may also have a vertical centerline extending parallel to the vertical direction at the center of the horizontal direction, a horizontal bottom line perpendicular to the vertical centerline at the bottom of the vertical direction, and an intersection of the vertical centerline and the horizontal bottom line. Furthermore, an upper angle UA (°) formed by an upper line and a horizontal bottom line passing through the intersection and passing through the uppermost and outermost positions of each of the pair of leg openings, and a lower angle LA (°) formed by a lower line and a horizontal bottom line passing through the intersection and passing through the lowermost and outermost positions of each of the pair of leg openings, may be defined as

[0119] In this case, it is preferable that the upper angle UA (°) and the lower angle LA (°) satisfy the following formula: 20<UA-LA. This widens the opening width of the leg openings, making it easier for the wearer to put their legs through the leg openings, and the disposable diaper has excellent leg passageability. Also, in this case, it is preferable that the upper angle UA (°) and the lower angle LA (°) satisfy the following formula: 2×LA<UA. This widens the opening width of the leg openings, making it easier for the wearer to put their legs through the leg openings, and the disposable diaper has excellent leg passageability.

[0120] The present disclosure will be described below using examples, but the present disclosure is not limited to these examples. [Manufacturing Example 1] Disposable diaper No. 1 according to the first embodiment was manufactured. Disposable diaper No. 1 was a size equivalent to large. Each of the pair of leg gathers of disposable diaper No. 1 included first to fifth elastic thread members. The first elastic thread member was a 310 dtex rubber thread and was fixed to the nonwoven fabric with an adhesive at a stretch ratio of 2.1. Each of the second to fifth elastic thread members was a 470 dtex rubber thread and was fixed to the nonwoven fabric with an adhesive at a stretch ratio of 2.1. The rubber thread constituting the first elastic thread member had the same composition as the rubber thread constituting the second to fifth elastic thread members. The elastic forces of the first to fifth elastic thread members and the elastic strength of disposable diaper No. 1 were compared. Table 1 shows the n-th distance of the n-th region at the intersection where the widthwise centerline of the leg gather portion intersects with each of the pair of leg gather portions.

[0121] [Manufacturing Example 2] Disposable diaper No. 2 was manufactured in the same manner as Manufacturing Example 1, except that the thickness (dtex), stretch ratio, and n-th distance of the rubber thread constituting the first to fifth thread-like elastic members were changed as shown in Table 1. The composition of the rubber thread constituting the multiple thread-like elastic members in disposable diaper No. 2 was the same as the rubber thread constituting the multiple thread-like elastic members in disposable diaper No. 1.

[0122] Disposable diapers No. 1 and No. 2 were put on the same volunteer wearer (weight: 14.3 kg) by multiple caregivers, and the ease of putting them on was evaluated. The number of times the wearer's legs got caught in a pair of leg gathers (v) and the number of times the wearer adjusted the waist portion of the disposable diaper (w) were measured when the caregiver was putting one disposable diaper on the wearer, and the average of the total values ​​of v + w was calculated to evaluate the ease of putting the diaper on. The smaller the number, the easier it was to put on.

[0123]

[0124] DESCRIPTION OF SYMBOLS 1 Disposable diaper 7 Crotch portion 8 Absorbent body 9 Absorbent body 23 Leg gathered portion 31 Thread-shaped elastic member 31a First thread-shaped elastic member 31b Second thread-shaped elastic member 31c Third thread-shaped elastic member 31d Fourth thread-shaped elastic member 31e Fifth thread-shaped elastic member 33 Nonwoven fabric sheet 33a Skin-side nonwoven fabric sheet 33b Non-skin-side nonwoven fabric sheet 35 Film sheet 37 Widthwise outer edge 41 First region 41D First distance 43 Second region 43D Second distance 45 Third region 45D Third distance

Claims

1. A disposable diaper which, in an unfolded state, has longitudinal, width, and thickness directions that are perpendicular to one another, and which comprises a ventral portion, a dorsal portion, and a crotch portion between the ventral portion and the dorsal portion, and which defines a waist opening and a pair of leg openings by connecting both sides of the width direction of the ventral portion and both sides of the width direction of the dorsal portion, wherein the disposable diaper comprises a pair of leg openings in the crotch portion and a pair of leg gathers that stretch in the longitudinal direction, and in the unfolded state, each of the pair of leg gathers comprises a fabric having a widthwise outer edge located at the outermost position in the width direction, and a plurality of thread-like elastic members fixed to the fabric so as to extend in the longitudinal direction on a widthwise inner side of the widthwise outer edge, and the plurality of thread-like elastic members comprises a first thread-like elastic member closest to the widthwise outer edge and a second thread-like elastic member adjacent to the first thread-like elastic member, When the region defined by the widthwise outer edge and the first thread-like elastic member is defined as a first region, and the region defined by the first thread-like elastic member and the second thread-like elastic member is defined as a second region, at an intersection where a widthwise center line extending parallel to the width direction at the longitudinal center of the disposable diaper intersects with each of the pair of leg gathered portions, a first distance which is the width of the first region in the width direction is longer than a second distance which is the width of the second region in the width direction.

2. The disposable diaper according to claim 1, wherein in the unfolded state, at the intersections where an area centered on the widthwise centerline and occupying 10% of the longitudinal length of the disposable diaper intersects with each of the pair of leg gathered portions, the first distance of the first area is longer than the second distance of the second area.

3. The disposable diaper according to claim 1 or 2, wherein the first distance is 5.0 to 12 mm in the unfolded state and at the intersection.

4. The disposable diaper according to any one of claims 1 to 3, wherein in the unfolded state and at the intersection, the first distance is 1.2 to 2.0 times longer than the second distance.

5. A disposable diaper as claimed in any one of claims 1 to 4, wherein in the unfolded state, the first thread-like elastic member is fixed to the fabric in a state in which it has the smallest elastic force among the plurality of thread-like elastic members.

6. A disposable diaper according to any one of claims 1 to 5, wherein in the unfolded state, the disposable diaper further comprises an absorbent main body having the pair of leg gathers and an absorber, and the plurality of thread-like elastic members further comprise an innermost thread-like elastic member arranged innermost in the width direction among the plurality of thread-like elastic members, and in the unfolded state, the innermost thread-like elastic member is fixed to the fabric in a state in which it has the highest elastic force among the plurality of thread-like elastic members.

7. The disposable diaper according to any one of claims 1 to 6, wherein in the unfolded state, the disposable diaper further comprises an absorbent main body having the pair of leg gathers and an absorber, the plurality of thread-like elastic members further comprising an innermost thread-like elastic member arranged innermost in the width direction among the plurality of thread-like elastic members, and when, in the unfolded state, each of the pair of leg gathers is equally divided between a first thread-like elastic member and the innermost thread-like elastic member into a 1 / 2 region from the first thread-like elastic member and a 2 / 2 region from the innermost thread-like elastic member, the sum of the elastic forces of the thread-like elastic members present in the 1 / 2 region among the plurality of thread-like elastic members at the intersection is smaller than the sum of the elastic forces of the thread-like elastic members present in the 2 / 2 region among the plurality of thread-like elastic members.

8. The disposable diaper according to any one of claims 1 to 7, wherein in the unfolded state, the disposable diaper further comprises an absorbent main body having the pair of leg gathers and an absorber, the plurality of thread-like elastic members further comprising an innermost thread-like elastic member arranged innermost in the width direction among the plurality of thread-like elastic members, and when, in the unfolded state, each of the pair of leg gathers is divided into thirds, between a first thread-like elastic member and the innermost thread-like elastic member, in order from the first thread-like elastic member side, into a 1 / 3 region, a 2 / 3 region, and a 3 / 3 region, at the intersection, the sum of the elastic forces of the thread-like elastic members present in the 1 / 3 region among the plurality of thread-like elastic members is smaller than the sum of the elastic forces of the thread-like elastic members present in the 3 / 3 region among the plurality of thread-like elastic members.

9. The disposable diaper according to any one of claims 1 to 8, wherein in the unfolded state, the disposable diaper further comprises an absorbent body arranged between the pair of leg gathers, and the plurality of thread-like elastic members further comprise an innermost thread-like elastic member arranged innermost in the width direction among the plurality of thread-like elastic members, and when, in the unfolded state, each of the pair of leg gathers is divided into four equal parts, between a first thread-like elastic member and the innermost thread-like elastic member, in order from the first thread-like elastic member side, into a 1 / 4 region, a 2 / 4 region, a 3 / 4 region, and a 4 / 4 region, at the intersection, the sum of the elastic forces of the thread-like elastic members present in the 1 / 4 region among the plurality of thread-like elastic members is smaller than the sum of the elastic forces of the thread-like elastic members present in the 4 / 4 region among the plurality of thread-like elastic members.

10. A disposable diaper according to any one of claims 1 to 9, wherein in the unfolded state and at the intersection, each of the pair of leg gathers has additional inelastic material in the entire second region but does not have additional inelastic material in a portion of the first region.

11. The disposable diaper according to any one of claims 1 to 10, wherein, in the disposable diaper laid flat, the number of pleats in the first region is less than the number of pleats in the second region.

12. A disposable diaper as claimed in any one of claims 1 to 11, wherein the plurality of thread-like elastic members further comprises a third thread-like elastic member adjacent to the second thread-like elastic member on the side opposite to the first thread-like elastic member, and when the area defined by the second thread-like elastic member and the third thread-like elastic member is defined as a third area, at the intersection in the unfolded state, a second distance of the second area is longer than a third distance, which is the width of the third area in the width direction.

13. The disposable diaper according to claim 12, wherein, when the disposable diaper is laid flat, the number of pleats in the first region is less than the number of pleats in the second region, and the number of pleats in the second region is less than the number of pleats in the third region.

14. When the disposable diaper is laid flat with the waist opening facing upward and the pair of leg openings facing left and right, the disposable diaper has a vertical direction and a horizontal direction corresponding to the longitudinal direction and the width direction, respectively, and the disposable diaper has a vertical centerline extending parallel to the vertical direction at the center of the horizontal direction, a horizontal bottom line perpendicular to the vertical centerline at the bottom of the vertical direction, and an intersection point of the vertical centerline and the horizontal bottom line, where an upper angle UA (°) is formed by an upper line passing through the intersection point and passing the uppermost and outermost position of each of the pair of leg openings and the horizontal bottom line, and a lower angle LA (°) is formed by a lower line passing through the intersection point and passing the lowermost and outermost position of each of the pair of leg openings and the horizontal bottom line, the upper angle UA (°) and the lower angle LA (°) can be calculated by the following formula: The disposable diaper according to any one of claims 1 to 13, which satisfies 20<UA-LA.

15. When the disposable diaper is laid flat with the waist opening facing upward and the pair of leg openings facing left and right, the disposable diaper has a vertical direction and a horizontal direction corresponding to the longitudinal direction and the width direction, respectively, a vertical centerline extending parallel to the vertical direction at the center of the horizontal direction, a horizontal bottom line perpendicular to the vertical centerline at the bottom of the vertical direction, and an intersection point between the vertical centerline and the horizontal bottom line, and when an upper angle UA (°) is formed by an upper line passing through the intersection point and passing the uppermost and outermost position of each of the pair of leg openings and the horizontal bottom line, and a lower angle LA (°) is formed by a lower line passing through the intersection point and passing the lowermost and outermost position of each of the pair of leg openings and the horizontal bottom line, the upper angle UA (°) and the lower angle LA (°) can be calculated by the following formula: 2 × LA < UA The disposable diaper according to any one of claims 1 to 14, which satisfies the above.

Images