Absorbent panty-type items

Abstract

This invention relates to a pant-type absorbent article that is comfortable around the abdomen and has a dorsal extension that prevents it from slipping down. [Solution] The outer casing of the pant-type absorbent article of the present invention has a ventral portion, a dorsal portion, and a pair of side seals. The dorsal portion of the outer casing has a dorsal extension portion that extends from the ventral waist end to the dorsal waist end in the longitudinal direction, and a dorsal main body portion that is the dorsal portion excluding the dorsal extension portion. The dorsal portion has a dorsal intermediate portion in which the lateral contraction stress is smallest within the first region, which is the area from 40 to 80% from the dorsal waist end when the distance from the dorsal waist end to the lower end of the side seal in the longitudinal direction is taken as 100%. The dorsal intermediate portion has a lateral contraction stress that is smaller than that of the ventral intermediate portion.

Description

Technical Field

[0001] The present invention relates to pants-type absorbent articles such as disposable diapers. Background Art

[0002] A pants-type absorbent article generally includes an absorbent main body, an exterior body, and side seals where the ventral exterior body and the dorsal exterior body are joined at their side end portions. The waist portion of the pants-type absorbent article is formed by joining the ventral exterior body and the dorsal exterior body via the side seals.

[0003] Patent Documents 1 and 2 disclose pants-type absorbent articles having a dorsal extension portion on the dorsal waist side of the exterior body. With such a configuration, for example, excreta such as loose stool is prevented from leaking from the dorsal side.

[0004] Patent Document 3 discloses a pants-type absorbent article in which the arrangement interval of elastic bodies is defined in order to improve fit, wearing comfort, prevent slipping down, prevent leakage, and prevent red marks from remaining on the skin. Prior Art Documents Patent Documents

[0005] Patent Document 1 Japanese Unexamined Patent Application Publication No. 2006-061680 Patent Document 2 Japanese Unexamined Patent Application Publication No. 2023-026803 Patent Document 3 Japanese Unexamined Patent Application Publication No. 2016-047225 Summary of Invention Problems to be Solved by the Invention

[0006] For example, when putting on and pulling up a pull-up type absorbent diaper for an infant or toddler who is lying face down or standing with support, it is common for the caregiver to insert their fingers from the back waistband of the pull-up type absorbent diaper and pull up the back portion of the diaper until it reaches the waist. However, with pull-up type absorbent diapers that have a back extension, there is a problem that the back portion is long and tends to roll up when the diaper is pulled up.

[0007] This invention relates to a pant-type absorbent article with a dorsal extension that is less likely to roll up. [Means for solving the problem]

[0008] A pant-type absorbent article according to one embodiment of the present invention comprises an absorbent body and an outer casing, and has a longitudinal direction extending from the wearer's abdominal side through the crotch area to the back, and a transverse direction perpendicular to the longitudinal direction. The outer casing described above is positioned on the non-skin side of the absorbent body and has a waist opening and a pair of leg openings. The above-mentioned outer casing has a ventral portion, a dorsal portion, and a pair of side seals. The ventral portion described above is positioned on the wearer's ventral side and has a ventral waist end that constitutes the waist opening described above. The aforementioned back portion is positioned on the wearer's back and has a back waist end that constitutes the waist opening. The pair of side seals described above are formed by joining the lateral edges of the ventral portion and the lateral edges of the dorsal portion in the lateral direction. The dorsal waist end is located further from the pair of leg openings in the longitudinal direction than the ventral waist end. The dorsal portion of the outer casing has a dorsal extension portion that extends in the longitudinal direction from the ventral waist end to the dorsal waist end, and a dorsal main body portion obtained by removing the dorsal extension portion from the dorsal portion. The above-mentioned side seal has an upper end and a lower end that are opposite to each other in the vertical direction. The dorsal portion has a dorsal intermediate portion within a first region, which is the area from the dorsal waist end to the lower end of the side seal, when the distance from the dorsal waist end to the lower end of the side seal in the longitudinal direction is taken as 100%, and is the area from the dorsal waist end to the lower end of the side seal. The ventral portion has a ventral intermediate portion that is in the same position as the dorsal intermediate portion in the longitudinal direction. The dorsal middle portion exhibits less lateral contractile stress than the ventral middle portion. [Effects of the Invention]

[0009] According to the absorbent pant-type article of the present invention, the dorsal extension is less likely to roll up when the diaper is pulled up. [Brief explanation of the drawing]

[0010] [Figure 1] This is a schematic perspective view showing a pant-type absorbent article according to an embodiment of the present invention. [Figure 2] (A) is a schematic side view of the above-mentioned pant-type absorbent article, and (B) is an enlarged view of the area enclosed by circle IIB in (A). [Figure 3] This is a schematic plan view showing the skin-facing side of the above-mentioned absorbent pant-type article, and is a diagram showing the absorbent pant-type article unfolded and the elastic bodies of each part stretched out to form a flat surface. [Figure 4] (A) is a schematic side view showing the arrangement of the elastic bodies of the pant-type absorbent article, and (B) is a schematic partial plan view illustrating the arrangement relationship of the elastic bodies of the ventral and dorsal parts, and the elastic body of the dorsal extension, which are joined by the side seals of the pant-type absorbent article, and shows the elastic bodies of each part stretched out into a planar shape. [Figure 5] This is a schematic cross-sectional view of the side seal and side reinforcement portion of the above-mentioned pant-type absorbent article. [Figure 6] This is a schematic plan view showing the side seal and side reinforcement portion of the above-mentioned pant-type absorbent article. [Figure 7](A) is a schematic perspective view showing a caregiver spreading the waist opening of the pant-type absorbent article with fingers, and (B) is a partially enlarged view of (A). [Figure 8] It is a schematic cross-sectional view of a side seal and a side reinforcing part of another aspect of the pant-type absorbent article. [Figure 9] It is a schematic perspective view showing a pant-type absorbent article according to another embodiment of the present invention. DETAILED DESCRIPTION OF EMBODIMENTS FOR CARRYING OUT THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that constituent elements already described are denoted by the same reference numerals, and descriptions thereof may be omitted.

[0012] [Overall Configuration of Pant-Type Absorbent Article] FIG. 1, FIG. 2(A) and FIG. 3 show a pant-type disposable diaper 1 as the pant-type absorbent article according to the embodiment of the present invention. Hereinafter, the pant-type disposable diaper 1 is referred to as the diaper 1. FIG. 2(A) schematically shows the diaper 1 in a worn state, and also illustrates the wearer's torso 13 and legs 14.

[0013] As shown in FIG. 1, the diaper 1 includes a waist opening 1W and a pair of leg openings 1L, and is worn around the wearer's waist and crotch when in use. The waist opening 1W has a waist opening end Wa. The diaper 1 has a longitudinal direction X and a transverse direction Y. The longitudinal direction X extends from the wearer's ventral side through the crotch portion to the dorsal side. The transverse direction Y is orthogonal to the longitudinal direction X and corresponds to the left-right direction of the wearer. Further, as shown in FIG. 2(A) and the like, the direction orthogonal to the longitudinal direction X and the transverse direction Y of the diaper 1 is defined as a thickness direction Z. As shown in FIG. 2(A) and the like, in the diaper 1 that is correctly worn by a wearer in a standing posture, the longitudinal direction X is parallel to the vertical direction.

[0014] In this specification, "waist side" and "upper side" mean the side in the vertical direction X that is closer to the waist opening end Wa of the waist opening 1W and away from the leg opening 1L. "Leg side" and "lower side" mean the side in the vertical direction X that is away from the waist opening end Wa and closer to the leg opening 1L. In this specification, "inside of transverse direction Y" means the side of the diaper (pant-type absorbent article) that is closer to the vertical center line CL that divides the diaper (pant-type absorbent article) in the transverse direction Y, and "outside of transverse direction Y" means the side that is further away from the vertical center line CL. In this specification, with respect to the thickness direction Z, the side of the diaper closer to the wearer's skin when worn is referred to as the "skin side," and the side closer to the clothing is referred to as the "non-skin side." Furthermore, "skin-facing surface" means the surface of the diaper or its components that faces the wearer's skin, i.e., the surface that is relatively close to the wearer's skin. "Non-skin-facing surface" means the surface of the diaper or its components that faces the opposite side (clothing side) from the skin-facing surface, i.e., the surface that is relatively far from the wearer's skin.

[0015] When an infant or toddler puts on diaper 1, they first put their legs through the pair of leg openings 1L, pull up diaper 1, and position diaper 1 around the wearer's waist and groin. In this specification, this series of actions is referred to as the "wearing action." The wearing action may also be performed by a caregiver rather than the wearer of diaper 1. For this reason, in this specification, the main performer of the wearing action is referred to as the "caregiver." In this specification, the state in which diaper 1 is positioned in the normally expected and appropriate wearing position for the wearer is referred to as "wearing."

[0016] When a caregiver puts a diaper 1 on a wearer, the wearer may be lying face down after rolling over, or standing with support. When putting a diaper 1 on a wearer who is facing away from the caregiver, typically the caregiver puts the wearer's legs through the leg openings 1L of the diaper 1, then grasps the back side 6 and pulls the diaper 1 up to the waist. In this specification, this pulling motion is referred to as the "pulling motion".

[0017] As shown in Figures 1, 2(A), and 3, the diaper 1 comprises an absorbent body 4 and an outer casing 5 positioned on the non-skin-facing side of the absorbent body 4. The diaper 1 also comprises first to fourth elastic bodies 71 to 74, a leg elastic body 11, and an elastic body 25 for forming a leak-proof cuff. Figure 3 shows the diaper 1 unfolded, with the elastic bodies of each part extended, and spread out flat to achieve the design dimensions, completely eliminating the influence of the elastic bodies. This form is also referred to as the "unfolded and extended state" of the diaper 1. Unfolding the diaper 1 means separating the ventral part 3 and the dorsal part 6 of the side seal 8, which will be described later.

[0018] The absorbent body 4 is fixed to the skin-facing side of the outer casing 5. The absorbent body 4 has at least an absorbent 40 and may further have a surface sheet 2, a back sheet 7, etc. For example, the absorbent body 4 has a configuration in which the back sheet 7, the absorbent 40 and the surface sheet 2 are laminated in the thickness direction Z (see Figure 5). The absorbent 40 includes a liquid-retaining absorbent core and may further include a core wrap sheet that covers the absorbent core. The absorbent body 4 has a dorsal end 106 located on the dorsal side 6, which is the end in the longitudinal direction X, and a ventral end 107 located on the ventral side 3, which is the end in the longitudinal direction X. The materials used in each component of the absorbent body 4 (back sheet 7, absorbent material 40, front sheet 2, etc.) can be any material used in the relevant art without any particular limitations.

[0019] The outer casing 5 includes a plurality of thermoplastic sheets 50. The outer casing 5 is configured, for example, as a laminate of a plurality of thermoplastic sheets 50. The thermoplastic sheet 50 is a sheet material mainly composed of thermoplastic resin. The thermoplastic sheet 50 preferably contains 90% by mass or more of thermoplastic resin, and more preferably consists of 100% by mass of thermoplastic resin. In addition, multiple thermoplastic sheets 50 may also contain cellulosic fibers in addition to thermoplastic fibers. Examples of thermoplastic resins include polyolefins such as polyethylene and polypropylene; polyesters such as polyethylene terephthalate; polyamides such as nylon 6 and nylon 66; polyacrylic acid, polyalkyl methacrylate, polyvinyl chloride, and polyvinylidene chloride. These can be used individually or in combination of two or more. The thermoplastic fibers may be short or long fibers. As thermoplastic fibers, composite fibers such as core-sheath type or side-by-side type, split fibers, irregularly shaped cross-section fibers, and heat-shrinkable fibers can also be used. Examples of cellulose fibers include natural cellulose fibers such as cotton and pulp, and regenerated cellulose fibers such as rayon and cupro. These can be used individually or in combination of two or more types.

[0020] As shown in Figure 3, the outer garment 5 has at least an abdominal portion 3 positioned on the wearer's abdominal side and a dorsal portion 6 positioned on the wearer's back side. The dorsal portion 6 has a dorsal extension 60 and a dorsal main body portion 61. The outer garment 5 of this embodiment further includes a crotch portion 9 located between the abdominal portion 3 and the dorsal portion 6 and positioned in the wearer's crotch area. In this example, the abdominal portion 3, the crotch portion 9, and the dorsal portion 6 are arranged along the longitudinal direction X. The outer garment 5 also has a shape that is constricted inward in the transverse direction Y at the crotch portion 9. This forms a leg opening 1L (see Figure 1) that follows the wearer's leg opening. The outer edge of the exterior body 5 is preferably constructed to be symmetrical (left-right symmetrical) with respect to the vertical center line CL.

[0021] Furthermore, the outer casing 5 has a pair of side seals 8, each formed by joining the lateral edge 54 of the ventral portion 3 in the lateral direction Y and the lateral edge 55 of the dorsal main body portion 61 in the lateral direction Y. In other words, the right side seal 8 has a configuration in which the right lateral edge 54 of the ventral portion 3 and the right lateral edge 55 of the dorsal main body portion 61 are joined together by overlapping them in the thickness direction Z. The left side seal 8 has a configuration in which the left lateral edge 54 of the ventral portion 3 and the left lateral edge 55 of the dorsal portion 6 are joined together by overlapping them in the thickness direction Z. The side seals 8 are preferably joined by heat sealing or ultrasonic sealing. The lateral edge portion 54 of the ventral portion 3 is a portion having a predetermined width, including the lateral edge 540 which is the lateral edge (lateral edge located on the left and right sides) of the ventral portion 3 in the lateral direction Y. The side edge portion 55 of the dorsal main body portion 61 is a portion having a predetermined width, including the side edge 550 which is the side edge (side edge located on the left and right) of the dorsal main body portion 61 in the lateral direction Y. The width of each of the side edges 54 and 55 is preferably 1.5 mm or more and 10 mm or less, more preferably 2 mm or more and 8 mm or less.

[0022] The outer casing 5 preferably includes, for example, an outer layer sheet 51 and an inner layer sheet 52 as a plurality of thermoplastic sheets 50, as shown in Figure 5. The outer layer sheet 51 is positioned on the non-skin side of the inner layer sheet 52 and constitutes the non-skin facing surface of the outer casing 5. It is preferable that first to fourth elastic bodies 71 to 74 are arranged between the inner layer sheet 52 and the outer layer sheet 51.

[0023] Furthermore, as shown in Figure 7(A), the diaper 1 further includes a disposal tape 12 having a handle portion, which is positioned on the back side 6 so as to overlap with the absorbent body 4 in a plan view.

[0024] As will be explained in more detail later, as shown in Figure 1, the dorsal portion 6 of the outer casing 5 of the diaper 1 is equipped with a dorsal extension 60. The dorsal extension 60 protrudes vertically upward from the ventral portion 3, which visually encourages the user to grasp the dorsal portion 6 and pull up the diaper 1. Thus, the diaper 1 is shaped in a way that facilitates the action of grasping the dorsal portion and pulling it up.

[0025] [Exterior structure] As shown in Figures 1, 2(A), and 3, the outer garment 5 has a ventral portion 3, a crotch portion 9, and a dorsal portion 6. The ventral portion 3 of the outer garment 5 has a ventral waist end 101 that constitutes the waist opening end Wa of the waist opening 1W. The dorsal portion 6 of the outer garment 5 has a dorsal waist end 102 that constitutes the waist opening end Wa of the waist opening 1W. The dorsal waist end 102 is located further from the pair of leg openings 1L in the longitudinal direction X than the ventral waist end 101. The dorsal waist end 102 is the end (dorsal extension end) of the dorsal extension portion 60. In the illustrated example, the dorsal waist end 102 is a straight line extending in the transverse direction Y, but is not limited to this, and may be a curved shape (rounded shape) that gently bulges upward in the longitudinal direction X, for example.

[0026] (Composition of the dorsal side) The dorsal portion 6 of the outer casing 5 has a dorsal extension 60 and a dorsal main body portion 61. The dorsal extension 60 extends in the longitudinal direction X from the ventral waist end 101 to the dorsal waist end 102. In the diaper 1, the dorsal extension 60 is the portion that protrudes upward from the ventral waist end 101. The dorsal main body portion 61 is the portion of the dorsal portion 6 excluding the dorsal extension 60. In other words, the dorsal main body portion 61 is the portion that is in the same position as the ventral portion 3 in the longitudinal direction X, while the dorsal extension 60 is the portion that does not face the ventral portion 3 and protrudes upward in the longitudinal direction X. As shown in Figures 1 and 3, the boundary between the dorsal extension 60 and the dorsal main body portion 61 (shown by a hypothetical dashed line) is denoted by reference numeral 103. The length of the dorsal extension portion 60 in the vertical direction X (i.e., the length from the boundary portion 103 to the dorsal waist end portion 102) is preferably, for example, 10 mm to 40 mm, from the viewpoint of good pulling-up operation of the diaper 1, effective suppression of the dorsal extension portion 60 rolling up, and effective suppression of leakage of excrement from the dorsal side. The length of the dorsal extension portion 60 in the vertical direction X refers to the minimum length. As shown in Figures 1 and 3, when the dorsal waist end portion 102 is a straight line parallel to the transverse direction Y, the length of the dorsal extension portion 60 in the vertical direction X (the length from the dorsal waist end portion 102 to the boundary portion 103 in the vertical direction X) is equal across the entire width in the transverse direction Y. However, when the dorsal waist end portion 102 is a curved shape that is convex upward in the vertical direction X, the length of the dorsal extension portion 60 in the vertical direction X is not equal across the entire width in the transverse direction Y. In this configuration, the length of the portion of the dorsal extension 60 where the length in the longitudinal direction X is minimized (minimum length) is defined as "the length of the dorsal extension 60 in the longitudinal direction X". The longer the dorsal extension 60, the better it can prevent loose stools and other excrement from leaking out. However, if it is too long, it becomes difficult to pull up the diaper 1, and the dorsal extension 60 is more likely to curl up. Therefore, it is preferable that the length of the dorsal extension 60 be 40 mm or less. On the other hand, if the dorsal extension 60 is too short, it is easy for the dorsal extension 60 to curl inward by hand when pulling up the diaper 1, making it difficult to pull up. Therefore, it is preferable that the length of the dorsal extension 60 be 10 mm or more.

[0027] The dorsal main body portion 61 of the dorsal portion 6 is divided into a dorsal upper portion 62, a dorsal middle portion 63, and a dorsal lower portion 64, as shown in Figures 3, 4(A), and (B). In other words, the dorsal portion 6 is divided into four parts: a dorsal extension portion 60, a dorsal upper portion 62, a dorsal middle portion 63, and a dorsal lower portion 64, which are arranged in order from the waist opening 1W toward the leg opening 1L.

[0028] As shown in Figure 3, when the diaper 1 is unfolded and the elastic bodies of each part are stretched to form a flat surface that matches the design dimensions with all influence from the elastic bodies eliminated, and the distance d from the back waist end 102 to the lower end 8b of the side seal is set to 100%, the back middle section 63 is located within the first region d1, which is the area from 40 to 80% of the back waist end 102. The back middle section 63 is the region within the first region d1 where the contraction stress in the lateral direction Y is smallest. Here, for example, when a caregiver puts a diaper on a wearer from behind, the caregiver inserts their fingers between the diaper 1 and the wearer, hooks their fingers onto the dorsal portion 6, and pulls the diaper 1 upwards. The first region d1 is the contact area of ​​the caregiver's fingers, which is suitable for performing the diaper-pulling motion smoothly and stably. That is, by inserting their fingers so that their fingertips are positioned in the first region d1, the entire diaper 1 can be easily spread with the fingers, and the diaper-pulling motion can be performed smoothly and stably while creating sufficient space between the diaper and the wearer. The dorsal middle portion 63 is located in the first region d1, which is the contact area of ​​the caregiver's fingers, which is suitable for such a smooth diaper-pulling motion.

[0029] In this embodiment, the dorsal intermediate portion 63 is the region with the smallest lateral Y shrinkage stress when the lateral Y shrinkage stress is measured along the vertical X from the dorsal waist end 102 to the side seal lower end 8b within the first region d1, in a range with a length of 30 mm in the vertical X direction. The above "range with a length of 30 mm in the vertical X direction" can be rephrased as the "measurement target range". When the lateral Y shrinkage stress of the measurement target range is measured while gradually shifting the position of the measurement target range along the vertical X direction within the first region d1, the measurement target range with the smallest lateral Y shrinkage stress is set as the dorsal intermediate portion 63. Hereinafter, "lateral Y shrinkage stress" may simply be referred to as "shrinkage stress".

[0030] Furthermore, if multiple 30mm regions with the smallest shrinkage stress can be obtained within the first region d1, 40-80% from the dorsal waist end 102, the uppermost 30mm region will be designated as the dorsal middle portion 63.

[0031] The portion between the dorsal middle portion 63 and the dorsal extension portion 60 becomes the dorsal upper portion 62. The portion of the dorsal portion 6 below the dorsal middle portion 63 becomes the dorsal lower portion 64.

[0032] (Composition of the ventral part) As shown in Figures 3, 4(A), and (B), the ventral portion 3 is divided into three parts: the upper ventral portion 32, the middle ventral portion 33, and the lower ventral portion 34, which are arranged in order from the waist opening 1W toward the leg opening 1L.

[0033] In the longitudinal direction X, the ventral upper portion 32 is in the same position as the dorsal upper portion 62, the ventral middle portion 33 is in the same position as the dorsal middle portion 63, and the ventral lower portion 34 is in the same position as the dorsal lower portion 64. In this specification, "being in the same position in the longitudinal direction X" means that, in the extended form shown in Figure 4(B), the ventral portion and the dorsal portion are adjacent and their position and length in the longitudinal direction X coincide. In diaper 1, the ventral upper portion 32 and the dorsal upper portion 62 are joined by a side seal 8 to form a ring. Similarly, the ventral middle portion 33 and the dorsal middle portion 63 form a ring and are located approximately near the wearer's ilium when worn. Similarly, the ventral lower portion 34 and the dorsal lower portion 64 form a ring. On the other hand, the dorsal extension portion 60 is not ring-shaped because there is no ventral portion in the same position in the longitudinal direction X, and is provided with a pair of dorsal extension side edges 104 that are free ends on both sides in the transverse direction Y. As shown in Figure 3, each of the pair of dorsal extension side edges 104 extends in the longitudinal direction X. The dorsal extension side edge 104 is a portion having a predetermined width that includes the dorsal extension side edges 1040, which are the side edges (side edges located on the left and right) of the dorsal extension 60 in the transverse direction Y. The width of the dorsal extension side edge 104 is preferably 1.5 mm or more and 10 mm or less, more preferably 2 mm or more and 8 mm or less.

[0034] [Composition of the absorbent body] Figure 5 is a schematic cross-sectional view of the side seal 8. Although the side seal 8 does not have an absorbent body 4, the absorbent body 4 is shown in Figure 5 for convenience to explain the positional relationship between the absorbent body 4 and the outer casing 5 in the article thickness direction (Z-axis direction). As shown in Figure 5, the outer casing 5 is folded back towards the skin-facing side at the ventral waist end 101 and the dorsal waist end 102. This folded portion is positioned to cover the dorsal end 106 and the ventral end 107 of the absorbent body.

[0035] As shown in Figures 3 and 5, the absorbent body 4 comprises a liquid-permeable surface sheet 2 that forms the skin side, a liquid-impermeable (including water-repellent) back sheet 7 that forms the non-skin side, and a liquid-retaining absorbent 40 positioned between the surface sheet 2 and the back sheet 7. The absorbent 40 and the surface sheet 2 are bonded together with an adhesive (not shown). The absorbent 40 and the back sheet 7 are bonded together with an adhesive (not shown).

[0036] As shown in Figure 3, each side of the absorbent body 4 along the longitudinal direction X is provided with a leak-proof cuff 24, which has an elastic body 25 for forming a leak-proof cuff that is stretched in the longitudinal direction X. The leak-proof cuff 24 is made of a material that is impermeable to liquid or water-repellent and breathable. The elastic body 25 for forming the leak-proof cuff is provided near the free end 24a of the leak-proof cuff 24. When the diaper 1 is worn, the contraction of the elastic body 25 causes the free end 24a side of the leak-proof cuff to stand up, forming a three-dimensional gather 15, which prevents the leakage of bodily fluids in the lateral direction Y. In addition, when the diaper 1 is pulled up, the contraction force of the elastic body 25 makes it easier to pull the absorbent body 4 up to the vicinity of the wearer's crotch.

[0037] In diaper 1, the total length of the absorbent body 4 in the vertical direction X is slightly longer than the total length of the absorbent material 40 in the vertical direction X. The ends 106 and 107 of the absorbent body 4 in the vertical direction X are located closer to the waist than the ends of the absorbent material 40 in the vertical direction X.

[0038] The absorbent body 40 of the absorbent main body 4 has an absorbent core (not shown) and a core wrap sheet (not shown).

[0039] A core wrap sheet is a liquid-permeable sheet that covers at least the skin-facing side of an absorbent core. Typically, the core wrap sheet is configured to cover the entire surface of the absorbent core, including both the skin-facing and non-skin-facing sides. Examples of core wrap sheets include tissue paper made of hydrophilic fibers and liquid-permeable nonwoven fabrics.

[0040] The absorbent core contains a superabsorbent polymer and pulp fibers. Specifically, the absorbent core is composed of, for example, an aggregate of hydrophilic fibers such as cellulose including pulp fibers, an aggregate of the hydrophilic fibers and a superabsorbent polymer, or a laminated structure in which a superabsorbent polymer is supported between two absorbent sheets.

[0041] As shown in Figure 1, the dorsal end 106 of the absorbent body is located closer to the leg opening 1L in the longitudinal direction X than the boundary 103. In other words, the absorbent body 4 is not positioned on the dorsal extension 60. This prevents the soft stool absorbed by the absorbent body 4 from moving to the dorsal extension 60, and prevents the soft stool from leaking from the dorsal waist end 102 of the outer casing 5.

[0042] The ventral end 107 of the absorbent body is located closer to the leg opening 1L in the longitudinal direction X than the dorsal end 106 of the absorbent body. In other words, in the longitudinal direction X, the dorsal end 106 of the absorbent body is located closer to the waist than the ventral end 107 of the absorbent body.

[0043] [Configuration of side seal and side reinforcement] A pair of side seals 8, each extending in the vertical direction X, cause the ventral portion 3 and the dorsal main body portion 61 to form a tubular shape that conforms to the wearer's waist, creating the waist opening 1W and leg openings 1L of the diaper 1. As shown in Figure 6, the side seals 8 typically include multiple sealing portions S.

[0044] In the side seal 8, the sealing portion S is the portion where the thermoplastic sheets 50 of both the ventral portion 3 and the dorsal main body portion 61 are fused and joined together. The sealing portion S is joined, for example, by pressurizing means and / or heating means, specifically by heat sealing or ultrasonic sealing. Multiple sealing portions S are arranged spaced apart in the longitudinal direction X and extend in the transverse direction Y. By arranging the multiple sealing portions S spaced apart in the longitudinal direction X, if one sealing portion S peels off, it is possible to prevent the entire side seal 8 from peeling off along the longitudinal direction X.

[0045] As shown in Figures 1 and 3, the pair of side reinforcing portions 105 are provided on the pair of back extension side edges 104 of the back extension portion 60, and are continuous with the side seal 8. As shown in Figure 6, the side reinforcing portion 105 includes multiple sealing portions S, similar to the side seal 8. In Figure 3, the area of ​​the side seal 8 is represented by dots, and the area of ​​the side reinforcing portion 105 is represented by diagonal lines.

[0046] In the example shown in Figure 6, the sealing portion S has a rectangular shape with the horizontal direction Y as its longitudinal direction. Multiple sealing portions S are intermittently arranged along the vertical direction X.

[0047] As shown in Figure 6, in the side seal 8 (side reinforcement portion 105), the rectangular area surrounding the entire contour of the multiple seal portions S is referred to as the seal region B. The seal region B is a region with higher rigidity compared to the region without seal portions S. Thus, the side seal 8 (side reinforcement portion 105) includes a rectangular, relatively rigid seal region B. The rigidity of the side reinforcement portion 105 is increased by the inclusion of the seal region B, and the dorsal extended side edge portion 104 is reinforced.

[0048] As shown in Figure 10, the width of the rectangular side seal 8, which extends in a band shape in the vertical direction X (corresponding to the width of the side edges 54 and 55), is defined as extending from the side edge on the inside of the seal area B in the horizontal direction Y to the side edge 540 of the ventral part 3 and the side edge 550 of the dorsal main body part 61. The side edge located on the lateral Y side of the side seal 8 is referred to as the inner side seal side edge 8d. This inner side seal side edge 8d coincides with the side edge located on the lateral Y side of the seal region B. The side edge located on the lateral Y-outward side of the side seal 8 is referred to as the outer side seal side edge 8c. This outer side seal side edge 8c coincides with side edges 540 and 550. As shown in Figure 6, each sealing portion S of the side seal 8 does not reach the side edges 540 and 550 in the lateral direction Y, and the side edges located on the lateral side Y of the sealing region B are located laterally inward from the side edges 540 and 550. In other words, the range of each of the left and right side seals 8 is the area from the side edge (inner side seal side edge 8d) that extends in the vertical direction X and is located inside the lateral direction Y of the rectangular seal area B, to the side edges 540 and 550.

[0049] As shown in Figure 10, the width range of the rectangular side reinforcement portion 105, which extends in a band shape in the vertical direction, is from the side edge on the inside of the seal area B in the lateral direction Y to the dorsal extension side edge 1040 of the dorsal extension portion 60. The side edge located on the inner side in the lateral direction Y of the side reinforcement portion 105 is referred to as the inner side reinforcement portion side edge 105d. This inner side reinforcement portion side edge 105d coincides with the side edge located on the inner side in the lateral direction Y of the seal region B. The side edge located on the lateral Y-outward side of the side reinforcement portion 105 is referred to as the outer side reinforcement portion side edge 105c. This outer side reinforcement portion side edge 105c coincides with the dorsal extension side edge 1040. As shown in Figure 6, each sealing portion S of the side reinforcement portion 105 does not reach the dorsal extending side edge 1040 in the lateral direction Y, and the side edges located on the outside in the lateral direction Y of the sealing region B are located inward in the lateral direction Y than the dorsal extending side edge 1040. In other words, in the dorsal extension portion 60, the range of each of the left and right pair of side reinforcing portions 105 is the region from the inner side reinforcing portion side edge 105d, which is the side edge extending in the vertical direction X located inside the lateral direction Y of the rectangular seal region B, to the dorsal extension side edge 1040.

[0050] As will be described in more detail later, multiple first elastic bodies 71 are arranged in the dorsal extension 60. The presence of a pair of side reinforcing parts 105 at both ends of the multiple first elastic bodies 71 in the lateral direction Y increases the rigidity of the pair of dorsal extension side edges 104, making the dorsal extension 60 less likely to curl up. Furthermore, since the pair of side reinforcing parts 105 are continuous with the side seal 8 and have a similar configuration including multiple sealing parts S, the diaper 1 can be manufactured simply without increasing the manufacturing process or materials.

[0051] Each pair of side seals 8 has an upper end portion 8a and a lower end portion 8b, which constitute both ends in the vertical direction X. Each pair of side seals 8 is continuous with a side reinforcing portion 105 provided on each of the pair of back extension side edges 104 of the back extension portion 60. In the continuous side seal 8 and side reinforcement portion 105, the upper end portion 8a of the side seal is located at the boundary between the side seal 8 and the side reinforcement portion 105. The upper end portion 8a of the side seal is the waist-side end of the side seal 8. The lower end portion 8b of the side seal is the leg-side end of the side seal 8.

[0052] As shown in Figures 2(A) and (B), the pair of side reinforcement portions 105 each have an upper end portion 105a and a lower end portion 105b, which constitute both ends in the vertical direction X. The upper end portion 105a of the side reinforcement portion is located at the back waist end portion 102. The lower end portion 105b of the side reinforcement portion corresponds to the boundary portion 110 between the side seal 8 and the side reinforcement portion 105, and is located at the same position as the upper end portion 8a of the side seal. In Figure 2(B), the boundary portion 110 is virtually shown with a thick dashed line.

[0053] As shown in Figure 2(A), the imaginary line 17 connecting the upper end (corresponding to the upper end 105a of the side reinforcement portion) and the lower end (corresponding to the lower end 8b of the side seal) of the entire side seal 8 and the side reinforcement portion 105 continuous therewith is a line that is diagonal to the vertical direction X, with the upper end located on the back side of the lower end.

[0054] [Contractile stress in the dorsal and ventral parts of the outer casing] As shown in Figures 3, 4(A), and (B), in the diaper 1, the dorsal portion 6 and the ventral portion 3 are each provided with a plurality of first to fourth elastic bodies 71 to 74 that extend in the transverse direction Y and are expandable and contractible in the transverse direction Y. By appropriately adjusting the fineness and / or elongation rate of the elastic bodies placed in each part, the number of elastic bodies, the spacing between the elastic bodies, etc., the contraction stress in the transverse direction Y of each part (dorsal extension 60, dorsal upper portion 62, dorsal middle portion 63, dorsal lower portion 64, ventral upper portion 32, ventral middle portion 33, ventral lower portion 34). The method for measuring the contraction stress will be described later. The elastic bodies placed in each part are fixed to the thermoplastic sheet 50 that constitutes the outer casing 5 in an extended state, and when the extended state is released and the elastic bodies contract, folds are naturally formed in the outer casing 5. The elastic bodies are fixed to the thermoplastic sheet 50, for example, by adhesive.

[0055] (Relationship of contractile stress between the dorsal and ventral middle sections) In diaper 1, the dorsal middle section 63 has less contractile stress in the lateral direction Y than the ventral middle section 33.

[0056] This configuration makes it easier for caregivers to put on the diaper from behind the wearer. Specifically, when putting on the diaper 1, the waist opening 1W of the diaper is typically widened by the caregiver's fingers 16. As shown in Figure 7(A), when fingers 16 are inserted into the waist opening 1W of the diaper 1 from behind, the caregiver's fingertips are positioned in the dorsal middle section 63. In the diaper 1, the dorsal middle section 63 has less contractile stress in the lateral direction Y than the ventral middle section 33, and the dorsal middle section 63 is less susceptible to the contractile force of the elastic material than the ventral middle section 33. Therefore, in the dorsal middle section 63, the movement of the caregiver's fingers inserted from the waist opening 1W is not easily restricted, and space is easily formed between the dorsal middle section 63 and the wearer for the caregiver's fingers to move, making it easier to hook the inside of the diaper 1 with the fingertips and pull it up, thus making it easier to put on the diaper 1 from behind the wearer. In addition, because the ventral middle section 33 has greater contractile stress than the dorsal middle section 63, the ventral middle section 33 is relatively less stretchable, and does not stretch excessively when the diaper 1 is pulled up. As a result, when the dorsal section 6 is hooked with the fingers and the diaper 1 is pulled up, the ventral section 3 easily follows and moves in the direction of pulling up the diaper 1, improving the ease of pulling up the diaper 1 and making it easier to put on the diaper.

[0057] Furthermore, in diaper 1, the dorsal middle portion 63 has a smaller contractile stress in the lateral direction Y than the ventral middle portion 33. As shown in Figures 1, 2(A), and 4(A), the dorsal middle portion 63 is pulled ventrally by the contractile force of the ventral middle portion 33, which has a larger contractile stress than the dorsal middle portion 63. For this reason, as shown in Figure 2(A), the side seal 8, which is the joint between the ventral portion 3 and the dorsal portion 6, and the side reinforcement portion 105, which is continuously provided on the side seal 8, are generally oblique to the vertical direction X when worn, with their upper end (upper end of side reinforcement portion 105a) leaning towards the dorsal side and their lower end (lower end of side seal 8b) leaning towards the ventral side (see dashed line 17 in Figure 2(A)). In particular, the dorsal extension portion 60 has no ventral portion to join to it, and the dorsal extension side edge portion 104 is a free end. Therefore, the dorsal extension side edge portion 104 tends to be more oblique with respect to the longitudinal direction X, such that its upper end (upper end portion 105a of the side reinforcement portion) is located dorsally more than its lower end (lower end portion 105b of the side reinforcement portion).

[0058] Thus, in diaper 1, the upper end (upper end of side reinforcement 105a) of the dorsal extension side edge 104 is positioned dorsally relative to its lower end (lower end of side reinforcement 105b). As a result, when putting on diaper 1, as shown in Figure 7(B), when a caregiver widens the waist opening 1W of diaper 1 with their fingers 16 and pulls up diaper 1, the middle and proximal joints of the fingers 16 are less likely to catch on the dorsal waist end 102. Therefore, the occurrence of the dorsal waist end 102 bending and the dorsal extension 60 rolling up due to force applied from the middle and proximal joints of the fingers 16 can be effectively suppressed. By ensuring that diaper 1 is worn in the correct position without the dorsal extension 60 rolling up, leakage of excrement such as loose stool from the dorsal side can be effectively suppressed.

[0059] Furthermore, because the contractile stress of the dorsal middle section 63 is small, the stool between the dorsal middle section 63 and the wearer's skin is prevented from being pushed upward by the contractile force of the elastic material, thereby further suppressing leakage of stool from the dorsal side.

[0060] As described above, by making the lateral Y-stress of the dorsal middle portion 63 smaller than that of the ventral middle portion 33, the dorsal extension edge portion 104 can be configured such that its upper end is located dorsally relative to its lower end. This configuration effectively suppresses the curling of the dorsal extension portion 60, improving the ease of pulling up the diaper. By suppressing the curling of the dorsal extension portion 60, the dorsal extension portion 60 effectively prevents leakage of excrement from the dorsal side.

[0061] In addition, while an elastic body is not required in the dorsal extension portion 60, it is preferable that an elastic body (first elastic body 71) is provided, as in the diaper 1 of this embodiment. By providing the first elastic body 71 in the dorsal extension portion 60, the contractile force of the first elastic body 71 causes the dorsal extension side edge portion 104 to become more oblique with respect to the vertical direction X, such that its upper end is located further back than its lower end. This further suppresses the curling of the dorsal extension portion 60. Furthermore, with the provision of the first elastic body 71, the dorsal extension portion 60 forms folds at its natural length, giving it thickness and making it more robust (firm) compared to the case where no elastic body is provided, further suppressing the curling of the dorsal extension portion 60 when the diaper 1 is pulled up.

[0062] Furthermore, while the side reinforcement portion 105 is not required on the side edge portion 104 of the dorsal extension portion 60, it is preferable that the side reinforcement portion 105 is provided, as in the diaper 1 of this embodiment. By placing the first elastic body 71 on the dorsal extension portion 60 and further providing the side reinforcement portion 105, the dorsal extension portion 60 becomes even more robust, and the curling of the dorsal extension portion 60 is further suppressed when the diaper 1 is pulled up.

[0063] Furthermore, as shown in Figure 2(B), in the diaper 1 of this embodiment, the side reinforcement portion 105 and the side seal 8 are continuous, so the dorsal extension portion 60 is less likely to bend at the boundary portion 110 between the side reinforcement portion 105 and the side seal 8, and consequently the bending of the dorsal extension portion 60 at the boundary portion 103 is suppressed. As a result, the curling of the dorsal extension portion 60 when the diaper 1 is pulled up is further suppressed.

[0064] (Relationship between contraction stress in the dorsal extension and dorsal intermediate portion) It is more preferable that the dorsal extension portion 60 has a greater contraction stress in the lateral direction Y than the dorsal intermediate portion 63.

[0065] This configuration makes it easier to reliably achieve a shape in which the side seal 8 and the side reinforcement portion 105 continuous with the side seal 8 are oblique to the vertical direction X, with the upper side (side reinforcement portion upper end 105a side) leaning towards the dorsal side and the lower side (side seal lower end 8b side) leaning towards the ventral side. As a result, when putting on the diaper 1, as shown in Figure 7(B), when widening and pulling up the waist opening 1W of the diaper 1, the middle and proximal joints of the caregiver's fingers 16 are less likely to get caught on the dorsal waist end 102, and the curling of the dorsal extension portion 60 is further suppressed. Furthermore, because the dorsal extension portion 60 has a greater contractile stress than the dorsal middle portion 63, the dorsal extension portion 60 can be made more robust, and the dorsal extension portion 60 is less likely to curl up during the pulling motion.

[0066] Furthermore, it is more preferable that the lateral Y-stress of the dorsal upper portion 62, located between the dorsal extension portion 60 and the dorsal intermediate portion 63, is greater than that of the dorsal intermediate portion 63. Thus, because the upper dorsal portion 62, which has greater contractile stress than the middle dorsal portion 63, is located just above the middle dorsal portion 63, it is possible to create a space between the outer body 5 and the wearer that makes it easier to bend the fingertips and to hook the inside of the outer body 5 with the fingertips, thereby improving the ease of pulling up the diaper.

[0067] Furthermore, it is more preferable that the lateral Y-stress of the dorsal upper portion 62, located between the dorsal extension portion 60 and the dorsal intermediate portion 63, is smaller than that of the dorsal extension portion 60 and larger than that of the dorsal intermediate portion 63. With this configuration, the contraction stress of the dorsal portion 6 decreases in stages from the dorsal extension portion 60 to the dorsal intermediate portion 63, thereby suppressing the occurrence of the dorsal extension portion 60 bending starting near the boundary between areas with large differences in contraction stress.

[0068] (Relationship of contractile stress between the dorsal extension and other parts) It is more preferable that the dorsal extension 60 has greater contractile stress in the lateral direction Y than the other parts that make up the dorsal portion 6 and the ventral portion 3, namely the dorsal upper portion 62, the dorsal middle portion 63, the dorsal lower portion 64, the ventral upper portion 32, the ventral middle portion 33, and the ventral lower portion 34. In this way, of the dorsal portion 6 and the ventral portion 3, the dorsal extension portion 60 is the part with the greatest contractile stress, making the dorsal extension portion 60, which is not ring-shaped and is prone to rolling up, more robust. This makes it less likely for the dorsal extension portion 60 to roll up when putting on the diaper 1, and makes it easier to put on the diaper 1.

[0069] (Relationship of contractile stress between the dorsal middle section and other parts) It is more preferable that the dorsal intermediate portion 63 has less contractile stress in the lateral direction Y than the other portions constituting the dorsal portion 6 and the ventral portion 3, namely the dorsal extension portion 60, the dorsal upper portion 62, the dorsal lower portion 64, the ventral upper portion 32, the ventral intermediate portion 33, and the ventral lower portion 34. In this way, by making the dorsal middle section 63 the area with the least contractile stress among the dorsal section 6 and ventral section 3, when putting on the diaper 1, the caregiver can insert their fingers 16 from the dorsal waist end 102 and easily bend the joints of their fingers 16 in the dorsal middle section 63, which is the area with the least contractile stress, making it easier to hook the outer body 5 with their fingertips from the skin side of the dorsal section 6. Furthermore, since the parts other than the dorsal middle section 63 do not stretch excessively, when hooking the dorsal section 6 with fingers and pulling up the diaper 1, the ventral section 3 easily follows and moves in the direction of pulling up, making it easier to pull up the diaper 1.

[0070] (Examples of contraction stress in each part) Examples of lateral Y-direction shrinkage stress in each part, measured using the shrinkage stress measurement method described later, are given below, but the values ​​listed here are not limited to those given. The shrinkage stress of the dorsal extension portion 60 is preferably 20 to 65 cN / 10 mm, and more preferably 25 to 60 cN / 10 mm. The shrinkage stress of the dorsal upper portion 62 is preferably 5 to 50 cN / 10 mm, and more preferably 10 to 45 cN / 10 mm. The shrinkage stress in the dorsal intermediate portion 63 is preferably 0 to 40 cN / 10 mm, and more preferably 0 to 30 cN / 10 mm. The shrinkage stress of the lower dorsal portion 64 is preferably 5 to 50 cN / 10 mm, and more preferably 10 to 45 cN / 10 mm. The contractile stress of the ventral upper portion 32 is preferably 5 to 50 cN / 10 mm, and more preferably 10 to 45 cN / 10 mm. The contractile stress in the ventral middle portion 33 is preferably 8 to 55 cN / 10 mm, and more preferably 13 to 40 cN / 10 mm. The contractile stress of the ventral lower portion 34 is preferably 5 to 50 cN / 10 mm, and more preferably 10 to 45 cN / 10 mm.

[0071] (Method for measuring contraction stress) The contraction stress in each part is measured as the contraction stress in the Y direction per unit length, as follows:

[0072] ((Measurement sample)) Peel off the side seal of the diaper, stretch and unfold it as shown in Figure 3 to spread it flat, and cut out the areas of the ventral portion 3 and the dorsal portion 6, respectively, along a straight line parallel to the width direction of the diaper, in the areas of the upper ventral portion 32, the middle ventral portion 33, the lower ventral portion 34, the dorsal extension portion 60, the upper dorsal portion 62, the middle dorsal portion 63, and the lower dorsal portion 64, respectively, to obtain strips or band-shaped samples of each part that extend across the entire lateral width between the side edges 54 of the ventral portion 3 and between the side edges 55 of the dorsal portion 6. When cutting out, the entire diaper, including the absorbent body 4, is cut, not just the ventral portion 3 and the dorsal portion 6, and the absorbent material 40 is removed. Alternatively, the ventral portion 3 and the dorsal portion 6 may be cut into their respective parts after removing the absorbent material 40. If an elastic body exists at the boundary between adjacent parts, the elastic body at the boundary is considered to be placed in the upper part (waist side part), and the cut is made in the part other than the adjacent elastic body. Record the length (in mm) of each cut sample in the vertical (X) and horizontal (Y) directions.

[0073] ((Measurement of contraction stress in the Y direction)) The sample is clamped at both ends in the chuck of a tensile testing machine (SHIMADZU "Autograph AG-X"), and stretched at a speed of 300 mm / min. The length between the side seals of the ventral and dorsal sides, measured by the inner dimensions of the ventral and dorsal sides, is set to 100 (e.g., 350 mm). The sample is stretched to a length equivalent to 80 (e.g., 280 mm), and then contracted to a length equivalent to 71 (e.g., 250 mm). The tensile load (cN) at this point is measured. This measured tensile load (cN) is converted to a tensile load (cN) per unit length (10 mm). The value obtained by dividing this converted tensile load (cN) per unit length (10 mm) by the length of the sample in the X direction is defined as the contraction stress P in the Y direction. The reason for defining the return force at a length equivalent to 71 when the inner dimensions of the ventral and dorsal parts are set to 100 is that the waist circumference of infants, who are the primary target of wearing the diaper 1 of this embodiment, is approximately 71% of the inner dimensions of the diaper. The waist circumference referred to here is the average value of the waist circumference measured in standing and sitting positions, taking into account the change in waist circumference when the posture of the infant changes. Each of the pair of side seals 8 (or side joints 105) has an inner edge (inner side seal side edge 8d or inner side reinforcement side edge 105d) located on the inside in the lateral Y direction, and the above "inner dimensions" refers to the distance between the pair of inner edges. Furthermore, the above "inner dimensions" refers to the inner dimensions when the sheet (thermoplastic sheet 50) constituting the outer body 5 is not contracted by the elastic body, in other words, when only the ventral and dorsal parts are stretched without the elastic body.

[0074] [Examples of elastic body constructions] As shown in Figures 3, 4(A), and (B), multiple first elastic bodies 71, second elastic body 72, third elastic body 73, and fourth elastic body 74 extending in the lateral direction Y are arranged on the ventral side 3 and dorsal side 6 of the outer casing 5. The fineness of each of the first to fourth elastic bodies 71 to 74 is different, and in Figures 3, 4(A), and (B), elastic bodies with different finenesses are shown with different wire types.

[0075] The first elastic body 71a and the first elastic body 71b are elastic bodies with the same fineness and elongation ratio, differing only in their placement in the same area. Unless there is a need to distinguish between them, they are referred to as the first elastic body 71. In the figure, the first elastic body 71 is shown by a dashed line. The second elastic bodies 72a, 72b, and 72c are elastic bodies that have the same fineness but differ in their placement, and their elongation rates differ depending on the location. Unless there is a need to distinguish them, they are referred to as the second elastic body 72. In the figure, the second elastic body 72 is shown by a dashed line. Third elastic bodies 73a, 73b, and 73c are elastic bodies with the same fineness and elongation ratio, differing only in their placement. Unless otherwise specified, they are referred to as the third elastic body 73. In the figure, the third elastic body 73 is shown by a dotted line. The fourth elastic body 74a and the fourth elastic body 74b are elastic bodies with the same fineness and elongation ratio, differing only in their placement. Unless there is a need to distinguish between them, they are referred to as the fourth elastic body 74. In the figure, the fourth elastic body 74 is shown by a dashed line.

[0076] From the viewpoint of ensuring the elasticity of the entire girth, the ends of the elastic bodies 71-74 located on the ventral portion 3 and the dorsal portion 6, respectively, on the lateral Y-side, are preferably located on or near the side seal 8 and the side reinforcement portion 105. Specifically, it is preferable that the distance of such ends from the side seal 8 and the side reinforcement portion 105 in the lateral Y-side is 10 mm or less, and it is more preferable that the distance is 0 mm and the ends are located within the side seal 8 and the side reinforcement portion 105.

[0077] The elongation rate of each of the first to fourth elastic bodies 71 to 74 represents the ratio of the length of the elastic body in the unfolded and stretched state of the pant-type absorbent article to the length of the elastic body in the natural length when removed from the pant-type absorbent article. In other words, the lower the elongation rate, the smaller the elastic force when each elastic body is stretched tends to be. The elongation rate of the elastic body can be adjusted during manufacturing by adjusting the degree of elongation of each elastic body placed in the outer casing 5. During manufacturing, for example, the elastic body is stretched to a predetermined length, adhesive is applied to the elastic body using a comb or the like, and the elastic body is fixed to the thermoplastic sheet 50 of the outer casing 5.

[0078] Figure 5 is a schematic cross-sectional view of the side seal 8 and side reinforcement portion 105 of the diaper 1 of this embodiment. As shown in Figure 3, when the unfolded diaper 1 is viewed from above, the absorbent body 4 is not present in the area where the side seal 8 and side reinforcement portion 105 are provided. However, in Figure 5, the absorbent body 4 is shown to explain the positional relationship in the longitudinal direction X between the dorsal end 106 and ventral end 107 of the absorbent body 4 and the side seal 8.

[0079] Multiple first to fourth elastic bodies 71 to 74 are arranged between multiple thermoplastic sheets 50 of the outer casing 5. In the example shown in Figure 5, the multiple elastic bodies 71 to 74 are arranged extending in the lateral direction Y between the outer layer sheet 51 and the inner layer sheet 52. These first to fourth elastic members 71 to 74 provide elasticity to the waist of the diaper 1, making it easier to put on and maintaining a good fit when worn. Furthermore, "the first to fourth elastic bodies 71 to 74 extend in the lateral direction Y" means that in the unfolded and extended state, the first to fourth elastic bodies 71 to 74 extend in the lateral direction Y. However, the above expression is not limited to the first to fourth elastic bodies 71 to 74 being parallel to the lateral direction Y in the unfolded and extended state, but also includes the state in which the whole extends in the lateral direction Y. In this embodiment, an example is given in which all of the elastic bodies 71 to 74 are parallel to the lateral direction Y. Furthermore, as shown in Figures 1 and 3, the outer casing 5 may include, in addition to the first to fourth elastic bodies 71 to 74, a leg elastic body 11 positioned around the leg opening 1L.

[0080] The first to fourth elastic bodies 71 to 74, the leg elastic body 11, and the leak-proof cuff forming elastic body 25 can preferably be thread-like (e.g., elastic thread) or string-like (e.g., flat elastic) materials with a rectangular, square, circular, or polygonal cross-section, or multifilament type thread-like materials. The materials for the first to fourth elastic bodies 71 to 74, the leg elastic body 11, and the leak-proof cuff forming elastic body 25 can be those conventionally used in absorbent articles such as disposable diapers, and are not particularly limited. Examples include synthetic rubbers such as styrene-butadiene, butadiene, isoprene, and neoprene, natural rubber, EVA, stretchable polyolefin, and polyurethane.

[0081] The following are examples of fineness and elongation rates for each of the first to fourth elastic bodies 71 to 74 that satisfy the contraction stress relationship of each part described above, but are not limited to the fineness and elongation rates listed here. The method for measuring the elongation rate will be described later. The first to fourth elastic bodies 71 to 74 each extend along the transverse direction Y and are intermittently arranged along the longitudinal direction X.

[0082] The first elastic material 71 is an elastic material with a fineness of 470 dtex and an elongation ratio of 3.2 times. The second elastic material 72a is an elastic material with a fineness of 310 dtex and an elongation ratio of 2.8 times. The second elastic bodies 72b and 72c are elastic bodies with a fineness of 310 dtex and an elongation ratio of 3.5 times. The third elastic material 73 (73a, 73b, and 73c) is an elastic material with a fineness of 780 dtex and an elongation ratio of 2.7 times. The fourth elastic material 74 (74a, 74b) is an elastic material with a fineness of 620 dtex and an elongation ratio of 2.5 times.

[0083] As shown in Figure 4(B), in diaper 1, the first elastic body 71 includes three first elastic bodies 71a and one first elastic body 71b. The three first elastic bodies 71a are located in the dorsal extension 60. The one first elastic body 71b is located in the dorsal upper part 62. The second elastic body 72 includes two second elastic bodies 72a, five second elastic bodies 72b, and one second elastic body 72c. The two second elastic bodies 72a are located in the dorsal upper part 62. The five second elastic bodies 72b are located in the ventral upper part 32. The one second elastic body 72c is located in the ventral middle part 33. The third elastic body 73 includes two third elastic bodies 73a, two third elastic bodies 73b, and four third elastic bodies 73c. ​​The two third elastic bodies 73a are provided in the dorsal upper part 62. The two third elastic bodies 73b are located in the dorsal middle part 63. The four third elastic bodies 73c are located in the ventral middle part 33. The fourth elastic body 74 includes four fourth elastic bodies 74a and four fourth elastic bodies 74b. The four fourth elastic bodies 74a are located in the dorsal lower part 64. The four fourth elastic bodies 74b are located in the ventral lower part 34.

[0084] The first to fourth elastic bodies 71 to 74 are each positioned between a pair of side reinforcing portions 105 or between a pair of side seals 8, extending in the lateral direction Y across the entire width of the lateral direction Y, and are arranged to be expandable and contractible in the lateral direction Y. The first to fourth elastic bodies 71 to 74 include continuous elastic bodies that have not been treated to prevent elastic stretching, such as by cutting, and discontinuous elastic bodies that have been treated in part to prevent elastic stretching, such as by cutting. The continuous elastic material exhibits continuous stretchability across the entire width in the lateral direction Y, between a pair of side reinforcement sections 105 or between a pair of side seals 8. The discontinuous elastic body is an elastic body that has been treated so that a portion of the area overlapping with the absorbent body 4 in a plan view is cut off, thereby preventing it from having elastic stretchability. The discontinuous elastic body does not exhibit elastic stretchability in the central part of the diaper 1 in the lateral direction Y, but exhibits elastic stretchability on both sides in the lateral direction Y. In this embodiment, an elastic body that has been treated so that a portion of it does not exhibit elastic stretchability by cutting is used as the discontinuous elastic body, but it is also possible to have a configuration in which no elastic body is placed in the area where elastic stretchability is not exhibited.

[0085] One or more elastic bodies are arranged in the dorsal extension 60. In this embodiment, as shown in Figure 4(B), three first elastic bodies 71a are arranged in the dorsal extension 60, which does not have a corresponding portion in the ventral portion 3. The first elastic bodies 71a are continuous elastic bodies. The dorsal extension 60 has a pair of dorsal extension side edges 104 facing each other in the lateral direction Y, a plurality of first elastic bodies 71, and a pair of side reinforcing portions 105. The plurality of first elastic bodies 71 are arranged between the pair of dorsal extension side edges 104.

[0086] As shown in Figure 4(B), two third elastic bodies 73b are arranged in the dorsal intermediate section 63, from top to bottom. Of the two third elastic bodies 73, the upper third elastic body 73b is a continuous elastic body, and the lower third elastic body 73b is a discontinuous elastic body. Note that one or more elastic bodies may be arranged in the dorsal intermediate section 63, or no elastic bodies may be arranged there.

[0087] As shown in Figure 4(B), the distance (elastic body spacing) between the third elastic body 73b located below the dorsal intermediate portion 63 and the fourth elastic body 74a located immediately below the third elastic body 73b (the uppermost of the four fourth elastic bodies 74a) is considerably wider than the elastic body spacing between adjacent elastic bodies in the longitudinal direction X in other parts of the ventral portion 3 and dorsal portion 6. The region between the third elastic body 73b located below the dorsal intermediate portion 63 and the fourth elastic body 74a located adjacent to and immediately below the third elastic body 73b, in which no elastic body exists in the longitudinal direction X, is referred to as the elastic body-absent region 68. The longitudinal dimension X of the elastic body-absent region 68 is preferably 12 to 50 mm, more preferably 15 to 40 mm, and the elastic body-absent region 68 is located within the dorsal intermediate portion 63.

[0088] In the longitudinal direction X, the ventral intermediate portion 33, which is in the same position as the dorsal intermediate portion 63, has one second elastic body 72c and four third elastic bodies 73c arranged in order from top to bottom. The one second elastic body 72c and the two upper elastic bodies of the four third elastic bodies 73c are continuous elastic bodies. The two lower elastic bodies of the four third elastic bodies 73c are discontinuous elastic bodies.

[0089] As shown in Figures 4(A) and (B), a third elastic body 73c is positioned in the ventral intermediate portion 33 at the same location in the longitudinal direction X as the region of the dorsal intermediate portion 63 where no elastic body is located in the longitudinal direction X (region without elastic body 68). With this configuration, the contractile stress differs between the dorsal and ventral sides in the region where the dorsal intermediate portion 63 and the ventral intermediate portion 33 are connected in a ring shape, with the contractile stress being greater in the ventral intermediate portion 33 than in the dorsal intermediate portion 63. Therefore, as described above, the dorsal intermediate portion 63 is pulled toward the ventral side by the contractile force of the elastic body located in the ventral intermediate portion 33, and the dorsal extended side edge 104 tends to become oblique with respect to the longitudinal direction X, such that its upper end (upper end of side reinforcement 105a) is located dorsally more than its lower end (lower end of side reinforcement 105b). This effectively suppresses the curling of the dorsal extended portion 60 when the diaper 1 is pulled up.

[0090] On the upper dorsal side 62, one first elastic body 71b, two second elastic bodies 72a, and two third elastic bodies 73a are arranged in order from top to bottom. These first elastic bodies 71b, 72a, and 73a have different fineness and elongation ratios. Five second elastic bodies 72b are arranged sequentially from top to bottom on the ventral upper part 32, which is in the same position in the longitudinal direction X as the dorsal upper part 62. The fineness and elongation of these five second elastic bodies 72b are the same as those of the second elastic body 72a arranged on the dorsal upper part 62. The elastic bodies located in the upper dorsal portion 62 and the upper ventral portion 32 are both continuous elastic bodies.

[0091] In the area where the dorsal upper portion 62 and the ventral upper portion 32 are connected in a ring shape, the contractile stress differs between the dorsal and ventral sides, with the ventral upper portion 32 exhibiting greater contractile stress than the dorsal upper portion 62. In addition to the configuration described above where the contractile stress of the ventral intermediate portion 33 is greater than that of the dorsal intermediate portion 63, the configuration also ensures that the contractile stress of the ventral upper portion 32 is greater than that of the dorsal upper portion 62. As a result, the dorsal extension edge portion 104 is more likely to be oblique with respect to the vertical direction X, such that its upper end (upper end of side reinforcement portion 105a) is located more dorsally than its lower end (lower end of side reinforcement portion 105b). This makes it possible to more effectively suppress the curling of the dorsal extension portion 60 when the diaper 1 is pulled up.

[0092] Furthermore, in the diaper 1 of this embodiment, in the area of ​​the upper dorsal portion 62 closest to the dorsal extension portion 60, a first elastic body 71b and a second elastic body 72a with different fineness and elongation rates are arranged, with the first elastic body 71b having the same fineness and elongation rate as the first elastic body 71a arranged in the dorsal extension portion 60. As a result, the portion from the dorsal extension portion 60 to the upper dorsal portion 62 where the fineness and elongation rate of the elastic body change (near the area between the first elastic body 71b and the uppermost second elastic body 72a) is located inward in the vertical X direction from the boundary portion 103, and by gradually reducing the shrinkage stress from the dorsal extension portion 60 to the upper dorsal portion 62, the dorsal extension portion 60 becomes less likely to fold at the boundary portion 103 between the dorsal extension portion 60 and the upper dorsal portion 62, and curling can be suppressed more effectively.

[0093] In the lower dorsal portion 64, four fourth elastic bodies 74a are arranged in order from top to bottom, with each having the same fineness and elongation ratio. The portion immediately above the uppermost of the four fourth elastic bodies 74a is the dorsal middle portion 63. In the ventral lower part 34, which is in the same position in the longitudinal direction X as the dorsal lower part 64, four fourth elastic bodies 74b, each having the same fineness and elongation ratio, are arranged in order from top to bottom. The elastic bodies located in the lower dorsal portion 64 and the lower ventral portion 34 are both discontinuous elastic bodies, and both have the same fineness and elongation ratio.

[0094] As shown in Figure 4(B), the five elastic bodies located on the upper dorsal portion 62 and the five elastic bodies located on the upper ventral portion 32 are designed to be positioned at the same location in the longitudinal direction X. Similarly, the two elastic bodies located on the middle dorsal portion 63 and the two upper elastic bodies located on the middle ventral portion 33 are designed to be positioned at the same location in the longitudinal direction X. Furthermore, the four elastic bodies located on the lower dorsal portion 64 and the four elastic bodies located on the lower ventral portion 34 are designed to be positioned at the same location in the longitudinal direction X, and the contraction stress is equal on both the dorsal and ventral sides in the area where the lower dorsal portion 64 and the lower ventral portion 34 are connected in a ring shape.

[0095] As shown in Figure 4(B), each elastic body located on the dorsal main body 61 may be positioned substantially the same as each elastic body located on the ventral body 3 in the longitudinal direction X. "Substantially the same position" means that any design misalignment that may occur during diaper manufacturing is within 3 mm. Figure 4(B) shows a state in which no such manufacturing misalignment occurs.

[0096] As shown in Figure 3, the leg elastic body 11 that forms the leg gathers may extend in the lateral direction Y near the side seal 8 and intersect with the fourth elastic body 74, which is an elastic body that forms the waist gathers. In this way, the area where the leg gathers and waist gathers are parallel and intersect makes it easier to pull up the crotch area 9 of diaper 1 to the wearer's crotch when pulling up diaper 1.

[0097] (Method for measuring the elongation rate of an elastic material) Diaper 1 is separated at the side seal 8 and unfolded, then stretched. Two marks are made on each elastic body using an oil-based pen, spaced apart La in the stretching direction, in the area not including the side seal 8. Next, each elastic body is peeled off diaper 1, and the length Lb between the two marks in the natural state (contracted state) of each elastic body is measured. This measurement is performed three times for each elastic body, and the elongation rate is determined by the arithmetic mean of the values ​​calculated using the formula "La / Lb". The spacing La can be, for example, 100 mm, but if the stretchable range is less than 100 mm, the spacing La should be as wide as possible.

[0098] (Relationship between the elongation rate of the elastic material located in the dorsal extension and the elongation rate of the elastic material located in the dorsal intermediate section) As in this embodiment, it is preferable that the elongation rate of the first elastic body 71a, which is arranged in the dorsal extension portion 60, is higher than the elongation rate of the third elastic body 73b, which is arranged in the dorsal intermediate portion 63. This configuration allows for a thicker and more robust dorsal extension 60, further suppressing the curling of the dorsal extension 60 when the diaper 1 is pulled up.

[0099] (Relationship between the number of continuous elastic bodies located in the dorsal middle section and the number of continuous elastic bodies located in the ventral middle section) As in this embodiment, it is preferable that the number of continuous elastic bodies arranged in the dorsal intermediate portion 63 is less than the number of continuous elastic bodies arranged in the ventral intermediate portion 33. The embodiment in which the number of continuous elastic bodies arranged in the dorsal intermediate portion 63 is less than the number of continuous elastic bodies arranged in the ventral intermediate portion 33 includes an embodiment in which the number of continuous elastic bodies arranged in the dorsal intermediate portion 63 is 0, and further includes an embodiment in which the number of discontinuous elastic bodies is also 0, i.e., no elastic bodies are arranged in the dorsal intermediate portion 63 at all. In this embodiment, there is one continuous elastic body arranged in the dorsal intermediate portion 63, and there are two continuous elastic bodies arranged in the ventral intermediate portion 33.

[0100] This configuration makes it easier for the caregiver's fingers to enter the dorsal portion 6 when pulling up the diaper 1, and prevents excessive stretching in the ventral portion 3, thus improving the ease of pulling up.

[0101] (Spacing of elastic bodies) Multiple elastic bodies are arranged in the ventral portion 3 and the dorsal portion 6, respectively, at intervals in the longitudinal direction. As shown in Figure 3, it is more preferable that the dorsal intermediate portion 63 has a portion where the above-mentioned spacing is wider than that of the dorsal extension portion 60. In particular, the spacing between the lower of the two third elastic bodies 73b arranged in the dorsal intermediate portion 63 and the fourth elastic body 74a located immediately below it is wider than the spacing between the first elastic bodies 71 arranged in the dorsal extension portion 60. The portion of the dorsal intermediate portion 63 with wide spacing between elastic bodies is an elastic body-free region 68 where no elastic bodies exist in the longitudinal direction X. Thus, because the dorsal extension 60 has areas where the elastic material spacing is narrower than in the dorsal middle section 63, the dorsal extension 60 has a higher elastic contraction force and becomes more robust. As a result, the dorsal extension 60 is less likely to roll up when the diaper is pulled up, and the caregiver can easily hook their fingers into the elastic material-free area 68, where the elastic material spacing is wider, making it easier to pull up the diaper.

[0102] Furthermore, as shown in Figure 3, it is more preferable that the dorsal intermediate portion 63 has a wider spacing between elastic bodies (elastic body-free region 68) than the dorsal upper portion 62 and dorsal lower portion 64 adjacent to the dorsal intermediate portion 63. This configuration makes it easier for fingers to reach into the dorsal middle section 63, making it easier to pull up the diaper.

[0103] Furthermore, as shown in Figure 3, it is more preferable that the dorsal intermediate portion 63 has a wider spacing between elastic bodies (elastic body-free region 68) than other portions (dorsal portion 6 and ventral portion 3 excluding the dorsal intermediate portion 63). This configuration allows for quick removal of the diaper, even at night. Specifically, the area without elastic material 68 is less sensitive to the fingertips than the area where elastic material is present, making it easier to spread the outer covering. Therefore, when changing diapers in dim lighting, such as at night, caregivers can intuitively grasp the position of the dorsal middle section 63 by touch and quickly remove the diaper by hooking their fingers into this section.

[0104] Furthermore, as in this embodiment, it is more preferable that the multiple elastic bodies (first elastic body 71a, second elastic body 72a, third elastic body 73a) located in the dorsal extension portion 60 and the dorsal upper portion 62 adjacent to the dorsal extension portion 60 are intermittently arranged at equal intervals in the vertical direction X. The dorsal extension 60 is a part that is prone to curling up, but with this configuration, when pulling up the diaper, it is easy to visually confirm that the dorsal extension 60 and the elastic body positioned on the dorsal upper part 62 are parallel, making it easier to determine that the dorsal extension 60 has not curled up.

[0105] (Color of the elastic material provided in the dorsal extension) Diapers typically use white elastic material, but non-white elastic material may also be used. The elastic material placed in the dorsal extension 60 may be of a different color from the elastic material placed in the dorsal main body 61 and the ventral part 3. For example, a non-white (e.g., blue) elastic material may be used for the elastic material placed in the dorsal extension 60, and a white elastic material may be used for the elastic material placed in the other parts. Furthermore, the first elastic material 71b placed in the upper dorsal part 62, which has the same fineness and elongation rate as the first elastic material 71a placed in the dorsal extension 60, may also be non-white.

[0106] With this configuration, by using a non-white elastic material for the elastic body placed in the easily rolled-up dorsal extension 60, the caregiver can easily determine which side is the dorsal side of the diaper 1. Furthermore, it is easy to visually confirm whether the arrangement of the multiple non-white elastic materials is parallel or not, and when pulling up the diaper, the caregiver can visually confirm that the multiple non-white elastic materials are arranged parallel to each other, thereby confirming that the diaper is not rolled up.

[0107] (Relationship between the elongation rates of the elastic bodies located in the ventral upper portion, the dorsal extension portion, and the dorsal upper portion, respectively) As in this embodiment, it is more preferable that the elongation rate of the elastic body (second elastic body 72b) located in the ventral upper part 32 is higher than the elongation rates of the elastic body (first elastic body 71) located in the dorsal extension 60 and the elastic bodies (second elastic body 72a and third elastic body 73a) located in the dorsal upper part 62, respectively. This configuration prevents the highly stretchable upper abdominal section 32 from stretching excessively around the waist of diaper 1. For example, when putting diaper 1 on an infant lying face down, the upper abdominal section 32 is more likely to experience greater friction with the floor or other surfaces compared to other parts of the abdominal section 3 and dorsal section 6. However, because it is less stretchable, it is less likely to get caught on the floor or other surfaces, making it easier to pull up diaper 1.

[0108] [Example of a laminated structure for exterior components] As shown in Figure 5, the exterior body 5 preferably includes a plurality of thermoplastic sheets 50, for example, an outer layer sheet 51 and an inner layer sheet 52. The outer layer sheet 51 is positioned on the non-skin side of the inner layer sheet 52 and forms the non-skin facing surface of the exterior body 5. First to fourth elastic bodies 71 to 74 are positioned between the inner layer sheet 52 and the outer layer sheet 51.

[0109] In this embodiment, the disposable pant-type diaper 1 has a folded structure in which at least a portion of the outer casing 5 is folded back from the waist opening end Wa towards the skin-facing side. In the back portion 6 of the diaper 1 shown in Figure 5, the laminated outer layer sheet 51 and inner layer sheet 52 are folded back from the back waist end 102 toward the skin-facing side. At this folded portion, the outer layer sheet 51 is longer in the vertical direction X than the inner layer sheet 52, and the end of the outer layer sheet 51 in the vertical direction X is located further inward in the vertical direction X than the end of the inner layer sheet 52 in the vertical direction X. In the back portion 6, where the outer casing 5 is folded back and two layers of outer casing 5 are laminated, the two layers of outer casing 5 are bonded together with adhesive 19. In the ventral portion 3 of diaper 1, the laminated outer layer sheet 51 and inner layer sheet 52 are folded back from the ventral waist end 101 towards the skin-facing side. In this folded portion, the outer layer sheet 51 is longer in the vertical direction X than the inner layer sheet 52, and the end of the outer layer sheet 51 in the vertical direction X is located inward in the vertical direction X than the end of the inner layer sheet 52 in the vertical direction X. In the ventral portion 3, where the outer casing 5 is folded back and two layers of outer casing 5 are laminated, the two layers of outer casing 5 are bonded together with adhesive 19.

[0110] In this embodiment, as shown in Figure 5, the back extension 60, to which the side reinforcement portion 105 is provided due to the folded structure of the outer casing 5, has a first laminated region R1 in which four thermoplastic sheets 50 are laminated.

[0111] As shown in Figure 5, due to the folded structure of the outer casing 5, the side seal 8 has multiple regions with different numbers of layers of thermoplastic sheets 50. The side seal 8 has a second layered region R2 in which 7 thermoplastic sheets 50 are layered, a third layered region R3 in which 6 thermoplastic sheets 50 are layered, a fourth layered region R4 in which 5 thermoplastic sheets 50 are layered, and a fifth layered region R5 in which 4 thermoplastic sheets 50 are layered.

[0112] As shown in Figure 5, the number of layers of thermoplastic sheets 50 in the dorsal extension portion 60 is four. The number of layers of thermoplastic sheets 50 in the dorsal intermediate portion 63 is three or two. Thus, it is preferable that the number of layers of thermoplastic sheets 50 in the dorsal extension portion 60 is greater than the number of layers of thermoplastic sheets 50 in the region of the dorsal intermediate portion 63 where the absorbent 40 is not present. With this configuration, the dorsal extension 60 is more robust due to having more layers than the area of ​​the dorsal middle section 63 where there is no absorbent material 40, making it less likely for the dorsal extension 60 to curl up when the diaper 1 is pulled up. In addition, in the dorsal middle section 63, the outer casing 5 is made easier to spread when pulling up the diaper 1, making it easier to reliably insert fingers between the diaper 1 and the wearer, thus improving the ease of pulling up.

[0113] In the example of diaper 1 shown in Figure 5, the number of layers in the dorsal extension 60 is constant at 4 layers across the entire length X direction. However, the dorsal extension 60 may have multiple regions with different numbers of layers. In this case, the "number of layers of sheets constituting the dorsal extension" is defined as the smallest number of layers. For example, if the length of the inner layer sheet 52 in the folded portion is short, and the dorsal extension 60 has regions with 4 layers of sheets and regions with 3 layers, the "number of layers of sheets constituting the dorsal extension" is set to 3 layers.

[0114] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention.

[0115] For example, in the diaper 1 of the above embodiment, an example was given in which no elastic material is provided in the folded portion of the outer casing 5. However, as shown in the diaper 1A in Figure 8, an elastic member may be provided in the folded portion of the inner outer casing 5 of the two stacked layers of outer casing 5, in both the dorsal extension 60 of the dorsal portion 6 and the ventral upper portion 32 of the ventral portion 3.

[0116] Furthermore, although the diaper 1 of the above embodiment has an example in which the outer body 5 has a configuration in which the ventral part 3, the dorsal part 6, and the crotch part 9 are integrated, it is not limited to this. For example, as in the pant-type diaper 1B shown in Figure 9, the outer body may be divided into a ventral part 3B and a dorsal part 6B. The diaper 1B consists of a rectangular ventral part 3B that is placed on the ventral side of the wearer, a rectangular dorsal part 6B that is placed on the dorsal side of the wearer, and a crotch part 9B that includes an absorbent body fixed across the ventral part 3B and the dorsal part 6B. The crotch part 9B has a crotch outer body 90 and an absorbent body (including a surface sheet, an absorbent body, and a back sheet). The crotch outer body 90 together with the ventral part 3B and the dorsal part 6B constitute the outer body of the diaper 1B. The dorsal part 6B has a dorsal extension 60. The side edges of the dorsal portion 6B and the side edges of the ventral portion 3B are joined together to form a pair of side seals 8.

[0117] In diaper 1B, as with diaper 1A, the contractile stress of the ventral middle portion 33 is made greater than that of the dorsal middle portion 63, so that the dorsal extended edge portion 104 is oblique to the longitudinal direction X, such that its upper end is located dorsally relative to its lower end. This makes the dorsal extended portion 60 less likely to curl up. In diaper 1B, as with diaper 1A, the contractile stress of each part can be adjusted by adjusting the fineness and / or elongation rate of the elastic body 78 placed in the ventral portion 3B and the dorsal portion 6B, respectively.

[0118] The absorbent pant-type article according to the present invention does not have to be a disposable diaper for infants; for example, it may be a disposable diaper for adults or children. Furthermore, the absorbent pant-type article according to the present invention does not have to be a disposable diaper, as long as it is an absorbent article of the type worn on the lower body. Examples of such absorbent pant-type articles include sanitary napkins in pant form.

[0119] With regard to the embodiments of the present invention described above, the following additional information is disclosed. <1> A pant-type absorbent article comprising an absorbent body and an outer body positioned on the non-skin-facing side of the absorbent body, having a waist opening and a pair of leg openings, having a longitudinal direction extending from the wearer's abdominal side through the crotch to the back, and a transverse direction perpendicular to the longitudinal direction, The exterior body is, A ventral portion positioned on the wearer's abdominal side and having an ventral waist end that constitutes the waist opening, A back portion positioned on the back of the wearer, having a back waist end that constitutes the waist opening, It has a pair of side seals, the lateral edge of the ventral portion and the lateral edge of the dorsal portion being joined together, The dorsal waist end is located further from the pair of leg openings in the longitudinal direction than the ventral waist end, The rear side portion of the exterior body is A dorsal extension extending from the ventral waist end to the dorsal waist end in the longitudinal direction, The dorsal main body portion obtained by removing the dorsal extension portion from the dorsal portion, It has, The side seal has an upper end and a lower end that are opposite to each other in the vertical direction. The dorsal portion has a dorsal intermediate portion within a first region, which is the area from the dorsal waist end to the lower end of the side seal, when the distance from the dorsal waist end to the lower end of the side seal in the longitudinal direction is taken as 100%, and is the area from the dorsal waist end to the lower end of the side seal. The ventral portion has a ventral intermediate portion that is in the same position as the dorsal intermediate portion in the longitudinal direction, The dorsal intermediate portion has less lateral contractile stress than the ventral intermediate portion. Absorbent pants. <2> The dorsal extension is, The pair of dorsal extension side edges facing each other in the lateral direction, A pair of side reinforcing portions provided on each of the pair of dorsal extension side edges and Displaced between the pair of dorsal extending side edges, one or more elastic bodies that extend laterally and are expandable and contractible in the laterally direction. Having, The aforementioned <1> Absorbent pant-type articles as described above. <3> The dorsal extension has greater lateral contraction stress than the dorsal intermediate portion. The aforementioned <1> or <2> Absorbent pant-type articles as described above. <4> The dorsal extension has one or more elastic bodies that extend in the lateral direction and are expandable in the lateral direction, The aforementioned dorsal intermediate portion has, or does not have, one or more elastic bodies that extend in the lateral direction and are expandable or contractible in the lateral direction. When an elastic body is placed in the dorsal intermediate portion, the elastic body placed in the dorsal extension portion includes an elastic body with a higher elongation rate than the elastic body placed in the dorsal intermediate portion. The aforementioned <1> ~ <3> A pant-type absorbent article described in any one of the following. <5> The back portion is divided into the upper back portion, the middle back portion, and the lower back portion, in order from the waist opening towards the leg opening. The ventral portion is divided into the upper ventral portion, the middle ventral portion, and the lower ventral portion, in order from the waist opening toward the leg opening. The dorsal extension has greater lateral contraction stress than the dorsal upper portion, dorsal middle portion, dorsal lower portion, ventral upper portion, ventral middle portion, and ventral lower portion. The aforementioned <1> ~ <4> A pant-type absorbent article described in any one of the following. <6> The back portion is divided into the upper back portion, the middle back portion, and the lower back portion, in order from the waist opening towards the leg opening. The ventral portion is divided into the upper ventral portion, the middle ventral portion, and the lower ventral portion, in order from the waist opening toward the leg opening. The dorsal intermediate portion has less lateral contraction stress than the dorsal extension, the dorsal upper portion, the dorsal lower portion, the ventral upper portion, the ventral intermediate portion, and the ventral lower portion. The aforementioned <1> ~ <5> A pant-type absorbent article described in any one of the following. <7> The dorsal body portion and the ventral portion each have a plurality of continuous elastic bodies that extend across the entire width in the lateral direction between the pair of side seals. The number of continuous elastic bodies located in the dorsal middle section is less than the number of continuous elastic bodies located in the ventral middle section. The aforementioned <1> ~ <6> A pant-type absorbent article described in any one of the following. <8> The ventral portion and the dorsal portion each have multiple elastic bodies that extend in the transverse direction and are spaced apart in the longitudinal direction, which are expandable and contractible in the transverse direction. The dorsal intermediate portion has a wider gap than the dorsal portion and the ventral portion excluding the dorsal intermediate portion. The aforementioned <1> ~ <7> A pant-type absorbent article described in any one of the following. <9> The exterior body is constructed by laminating multiple sheets, The number of layers of the sheets constituting the dorsal extension is greater than the number of layers of the sheets constituting the dorsal intermediate portion. The aforementioned <1> ~ <8> A pant-type absorbent article described in any one of the following. <10> The ventral portion and the dorsal portion each have a plurality of elastic bodies that extend in the transverse direction and are expandable in the transverse direction, The aforementioned back body portion includes the upper back portion and the middle back portion, which are arranged in order from the waist opening side toward the leg opening, The ventral portion includes the upper ventral portion and the middle ventral portion, which are arranged sequentially from the waist opening toward the leg opening. The elastic body positioned in the ventral upper portion has a higher elongation rate than the elastic body positioned in the dorsal extension portion and the elastic body positioned in the dorsal upper portion. The aforementioned <1> ~ <9> A pant-type absorbent article described in any one of the following. <11> The absorbent body is provided with three-dimensional gathers that extend in the vertical direction along the lateral portion in the horizontal direction. The aforementioned <1> ~ <10> A pant-type absorbent article described in any one of the following. <12> The absorbent body has a dorsal end of the absorbent body, which is the longitudinal end located on the dorsal side, and a ventral end of the absorbent body, which is the longitudinal end located on the ventral side. The dorsal end of the absorbent body is located closer to the leg opening in the longitudinal direction than the boundary portion which is the boundary between the dorsal extension portion and the dorsal body portion. The ventral end of the absorbent body is located closer to the leg opening in the longitudinal direction than the dorsal end of the absorbent body. The aforementioned <1> ~ <11> A pant-type absorbent article described in any one of the following. <13> The dorsal extension is, The pair of dorsal extension side edges facing each other in the lateral direction, A pair of side reinforcing portions provided on each of the pair of dorsal extension side edges and It has, The pair of side reinforcing portions are continuous with the pair of side seals, The side reinforcement portion includes a plurality of sealing portions formed by pressurizing means and / or heating means. The aforementioned <1> ~ <12> A pant-type absorbent article described in any one of the following. <14> The dorsal extension is, The pair of dorsal extension side edges facing each other in the lateral direction, A pair of side reinforcing portions provided on each of the pair of dorsal extension side edges and It has, The pair of side reinforcing portions are continuous with the pair of side seals, When worn, the continuous side seals and side reinforcements are generally angled with respect to the longitudinal direction, with their upper ends towards the back and their lower ends towards the front. The aforementioned <1> ~ <13> A pant-type absorbent article described in any one of the following. <15> The back portion is divided into the upper back portion, the middle back portion, and the lower back portion, in order from the waist opening towards the leg opening. The shrinkage stress of the dorsal extension is 20-65 cN / 10 mm. The shrinkage stress in the upper dorsal portion is 5-50 cN / 10 mm. The shrinkage stress in the dorsal intermediate portion is 0 to 40 cN / 10 mm. The contraction stress in the lower dorsal portion is 5-50 cN / 10 mm. The aforementioned <1> ~ <14> A pant-type absorbent article described in any one of the following. <16> The ventral portion is divided into the upper ventral portion, the middle ventral portion, and the lower ventral portion, in order from the waist opening toward the leg opening. The contractile stress in the ventral upper portion is 5-50 cN / 10 mm. The contractile stress in the ventral middle portion is 8-55 cN / 10 mm. The contractile stress in the ventral lower portion is 5-50 cN / 10 mm. The aforementioned <1> ~ <15> A pant-type absorbent article described in any one of the following. <17> The back portion is divided into the upper back portion, the middle back portion, and the lower back portion, in order from the waist opening towards the leg opening. The ventral portion is divided into the upper ventral portion, the middle ventral portion, and the lower ventral portion, in order from the waist opening toward the leg opening. The dorsal and ventral portions have first to fourth elastic bodies of different fineness, which are stretchable in the transverse direction and arranged to extend in the transverse direction. The first elastic body includes three first elastic bodies arranged in the dorsal extension and one first elastic body arranged in the upper dorsal portion. The second elastic body includes two second elastic bodies positioned on the upper dorsal side, five second elastic bodies positioned on the upper ventral side, and one second elastic body positioned in the middle ventral side. The third elastic body includes two third elastic bodies provided on the upper dorsal side, two third elastic bodies positioned in the middle dorsal side, and four third elastic bodies positioned in the middle ventral side. The fourth elastic body includes four fourth elastic bodies positioned on the lower dorsal side and four fourth elastic bodies positioned on the lower ventral side. The aforementioned <1> ~ <16> A pant-type absorbent article described in any one of the following. <18> The first elastic material is an elastic material with a fineness of 470 dtex and an elongation ratio of 3.2 times. The second elastic body positioned on the upper dorsal side is an elastic body with a fineness of 310 dtex and an elongation ratio of 2.8 times. The second elastic body, positioned in the upper ventral portion and the middle ventral portion, is an elastic body with a fineness of 310 dtex and an elongation ratio of 3.5 times. The third elastic material is an elastic material with a fineness of 780 dtex and an elongation ratio of 2.7 times. The fourth elastic material has a fineness of 620 dtex and an elongation ratio of 2.5 times. The aforementioned <17> Absorbent pant-type articles as described above. <19> The aforementioned dorsal intermediate portion has an elastic body-free region in which no elastic body exists in the longitudinal direction, The vertical dimension of the region where the elastic body is absent is 12 to 50 mm. The aforementioned <1> ~ <18> A pant-type absorbent article described in any one of the following. <20> The aforementioned dorsal intermediate portion has an elastic body-free region in which no elastic body exists in the longitudinal direction, In the ventral intermediate portion, the elastic body is positioned in the same location in the longitudinal direction as the region where the elastic body is absent. The aforementioned <1> ~ <19> A pant-type absorbent article described in any one of the following. <21> The aforementioned back body portion includes the upper back portion and the middle back portion, which are arranged in order from the waist opening side toward the leg opening, The ventral portion includes the upper ventral portion and the middle ventral portion, which are arranged sequentially from the waist opening toward the leg opening. The ventral upper portion has greater lateral contractile stress than the dorsal upper portion. The aforementioned <1> ~ <20> A pant-type absorbent article described in any one of the following. <22> The back portion is divided into the upper back portion, the middle back portion, and the lower back portion, in order from the waist opening towards the leg opening. The ventral portion is divided into the upper ventral portion, the middle ventral portion, and the lower ventral portion, in order from the waist opening toward the leg opening. In the region where the dorsal lower part and the ventral lower part are connected in a ring shape, the contractile stress is equal on the dorsal and ventral sides. The aforementioned <1> ~ <21> A pant-type absorbent article described in any one of the following. <23> The ventral portion and the dorsal portion each have an elastic body that extends in the transverse direction and is expandable and contractible in the transverse direction. The elastic body located in the dorsal extension is non-white, while the elastic bodies located in the other dorsal and ventral portions are white. The aforementioned <1> ~ <22> A pant-type absorbent article described in any one of the following. <24> The aforementioned back body portion includes the upper back portion and the middle back portion, which are arranged in order from the waist opening side toward the leg opening, The ventral portion and the dorsal portion each have elastic bodies of different fineness that extend in the transverse direction and are expandable in the transverse direction. The elastic body positioned in the dorsal extension and the elastic body positioned in the upper dorsal portion, which has the same fineness as the elastic body positioned in the dorsal extension, are non-white, while the other elastic bodies positioned in the dorsal and ventral portions are white. The aforementioned <1> ~ <22> A pant-type absorbent article described in any one of the following. <25> The ventral portion and the dorsal portion each have a rectangular shape. It has a crotch area that is fixed across the ventral and dorsal portions, The aforementioned crotch area includes the crotch outer casing and the absorbent main body. The crotch outer covering, together with the ventral and dorsal portions, constitutes the outer covering. The aforementioned <1> ~ <24> A pant-type absorbent article described in any one of the following. [Explanation of Symbols]

[0120] 1, 1A, 1B...Panty-type absorbent items (disposable diapers, diapers) 1W…Waist opening 1L... Leg opening 3...Ventral part 4… Absorbent body 5…Exterior 6...Dorsal part 8... Side seal 8a... Upper end of side seal 8b... Lower end of side seal 33...Ventral middle section 60...Dorsal extension part 61...Dorsal body part 63…Dorsal middle part 101...Ventral waist end 102...Rear waist end d... Distance from the back waist end to the lower end of the side seal d1…First region (the region covering 40-80% of the distance d from the dorsal waist end)

Claims

1. A pant-type absorbent article comprising an absorbent body and an outer body positioned on the non-skin-facing side of the absorbent body, having a waist opening and a pair of leg openings, having a longitudinal direction extending from the wearer's abdominal side through the crotch to the back, and a transverse direction perpendicular to the longitudinal direction, The exterior body is, A ventral portion positioned on the wearer's abdominal side and having an ventral waist end that constitutes the waist opening, A back portion positioned on the back of the wearer, having a back waist end that constitutes the waist opening, It has a pair of side seals, the lateral edge of the ventral portion and the lateral edge of the dorsal portion being joined together, The dorsal waist end is located further from the pair of leg openings in the longitudinal direction than the ventral waist end, The rear side portion of the exterior body is A dorsal extension extending from the ventral waist end to the dorsal waist end in the longitudinal direction, The dorsal main body portion obtained by removing the dorsal extension portion from the dorsal portion, It has, The side seal has an upper end and a lower end that are opposite to each other in the vertical direction. The dorsal portion has a dorsal intermediate portion within a first region, which is the area from the dorsal waist end to the lower end of the side seal in the longitudinal direction, when the distance from the dorsal waist end to the lower end of the side seal in the longitudinal direction is taken as 100%, and the lateral shrinkage stress is smallest within the first region. The ventral portion has a ventral intermediate portion that is in the same position as the dorsal intermediate portion in the longitudinal direction, The dorsal intermediate portion has less lateral contractile stress than the ventral intermediate portion. Absorbent pants.

2. The dorsal extension is, The pair of dorsal extension side edges facing each other in the lateral direction, A pair of side reinforcing portions provided on each of the pair of dorsal extension side edges and Displaced between the pair of dorsal extending side edges, one or more elastic bodies that extend laterally and are expandable and contractible in the laterally direction. The pant-type absorbent article according to claim 1, having the following characteristics.

3. The dorsal extension has greater lateral contraction stress than the dorsal intermediate portion. The pant-type absorbent article according to claim 1 or 2.

4. The dorsal extension has one or more elastic bodies that extend in the lateral direction and are expandable and contractible in the lateral direction. The dorsal intermediate portion has, or does not have, one or more elastic bodies that extend in the lateral direction and are expandable or contractible in the lateral direction. When an elastic body is placed in the dorsal intermediate portion, the elastic body placed in the dorsal extension portion includes an elastic body with a higher elongation rate than the elastic body placed in the dorsal intermediate portion. The pant-type absorbent article according to claim 1 or 2.

5. The back portion is divided into the upper back portion, the middle back portion, and the lower back portion, in order from the waist opening towards the leg opening. The ventral portion is divided into the upper ventral portion, the middle ventral portion, and the lower ventral portion, in order from the waist opening toward the leg opening. The dorsal extension portion is the dorsal upper portion, the The lateral contraction stress is greater in the dorsal middle portion, the dorsal lower portion, the ventral upper portion, the ventral middle portion, and the ventral lower portion. The pant-type absorbent article according to claim 1 or 2.

6. The back portion is divided into the upper back portion, the middle back portion, and the lower back portion, in order from the waist opening towards the leg opening. The ventral portion is divided into the upper ventral portion, the middle ventral portion, and the lower ventral portion, in order from the waist opening toward the leg opening. The dorsal intermediate portion has less lateral contraction stress than the dorsal extension, the dorsal upper portion, the dorsal lower portion, the ventral upper portion, the ventral intermediate portion, and the ventral lower portion. The pant-type absorbent article according to claim 1 or 2.

7. The dorsal body portion and the ventral portion each have a plurality of continuous elastic bodies that extend across the entire width in the lateral direction between the pair of side seals. The number of continuous elastic bodies located in the dorsal middle section is less than the number of continuous elastic bodies located in the ventral middle section. The pant-type absorbent article according to claim 1 or 2.

8. The ventral portion and the dorsal portion each have multiple elastic bodies that extend in the transverse direction and are spaced apart in the longitudinal direction, which are expandable and contractible in the transverse direction. The dorsal intermediate portion has a wider gap than the dorsal portion and the ventral portion excluding the dorsal intermediate portion. The pant-type absorbent article according to claim 1.

9. The exterior body is constructed by laminating multiple sheets, The number of layers of the sheets constituting the dorsal extension is greater than the number of layers of the sheets constituting the dorsal intermediate portion. The pant-type absorbent article according to claim 1 or 2.

10. The ventral portion and the dorsal portion each have a plurality of elastic bodies that extend in the transverse direction and are expandable in the transverse direction, The aforementioned back body portion includes the upper back portion and the middle back portion, which are arranged in order from the waist opening side toward the leg opening, The ventral portion includes the upper ventral portion and the middle ventral portion, which are arranged sequentially from the waist opening toward the leg opening. The elastic body positioned in the ventral upper portion has a higher elongation rate than the elastic body positioned in the dorsal extension portion and the elastic body positioned in the dorsal upper portion. The pant-type absorbent article according to claim 1 or 2.

11. The absorbent body is provided with three-dimensional gathers that extend in the vertical direction along the lateral portion in the horizontal direction. The pant-type absorbent article according to claim 1 or 2.

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