Underpants type absorbent article

Abstract

To provide an underpants type absorbent article which can achieve an appearance like underwear and excellent liquid absorption properties in an absorption state of an excreted liquid in wearing.SOLUTION: An underpants type wearing article includes an absorber 16 which is arranged in a front-back direction Y connecting a crotch part 10C, an abdominal side part 10F, and a back side part 10R and includes an absorbent core 16A and a crotch stretchable member which is arranged closer to a non-skin surface side than the absorbent core 16A and can extends in the front-back direction Y in a region overlapped at least with the absorbent core 16A of the crotch part 10C. A member which includes the crotch stretchable member and is closer to the non-skin surface side than the absorbent core 16A in the crotch part 10C extends at least 1.1 times and 1.5 times or less a natural state before wearing in applying tensile load of 2 N / 50 mm in the front-back direction Y. In the crotch part 10C, the member which is closer to the non-skin surface side than the absorbent core 16A extends at least in the front-back direction Y in association with the extension of the crotch stretchable member when the absorbent core 16A absorbs a liquid.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to pant-type absorbent articles such as diapers. [Background technology]

[0002] Pants-type absorbent articles such as diapers have an outer cover and an absorbent main body arranged on the skin-facing side of the outer cover. The absorbent main body contains an absorbent core that absorbs and retains excrement, and is arranged to extend in the front-to-rear direction from the ventral side to the dorsal side while corresponding to the crotch region of the wearer. For such pants-type absorbent articles, a technique for forming an elastic region in the crotch region is known from the viewpoint of making it easier to pull up the crotch region to improve fit and preventing the article from sagging even when urinating, etc. (e.g., Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-29449 [Patent Document 2] Japanese Patent Application Publication No. 2019-118556 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a demand for pants-type absorbent articles such as those described above to have an appearance similar to that of regular underwear. By "underwear-like appearance," we mean that the outer contour of the crotch area of ​​the article resembles a V-shape that follows the line of the wearer's groin. For example, with regard to diapers for infants, parents desire to wean their children off diapers as they get older. To motivate them to wean themselves off diapers, there is a need for diapers that are more similar in shape to underwear so that they can become accustomed to them. Furthermore, not only for infants but also for adult diapers, there is a trend toward an underwear-like appearance from the standpoint of the wearer's self-esteem and public satisfaction. To meet these demands, it has been considered to narrow the width of the crotch portion of pants-type absorbent articles from conventional widths to bring the outer contour closer to that of underwear. However, simply narrowing the width of the crotch portion would also narrow the width of the absorbent core contained in the crotch portion, which could result in a decrease in liquid absorption capacity. In particular, when the absorbent core contains a superabsorbent polymer material, this could easily cause inhibition of swelling of the superabsorbent polymer material (gel blocking), which could result in insufficient liquid absorption. Furthermore, conventional pants-type absorbent articles may have an unsightly appearance due to the entire crotch area sagging after absorption depending on the amount of excrement from the wearer. For these reasons, there is room for improvement in conventional pants-type absorbent articles in order to achieve both excellent liquid absorbency while maintaining an underwear-like appearance at least while the article is being worn.

[0005] In view of the above, the present invention relates to a pants-type absorbent article that can achieve both underwear-like appearance and excellent liquid absorbency when in a state where it is absorbing excreted liquid while being worn. [Means for solving the problem]

[0006] The present invention provides a pants-type wearing article which is divided into a abdominal portion arranged on the abdominal side of a wearer, a crotch portion arranged on the crotch side, and a dorsal portion arranged on the dorsal side, which has a body length direction and a width direction perpendicular to the body length direction, and which includes a pair of side seal portions where both side edges of the abdominal portion and the dorsal portion are joined together, an absorbent body including an absorbent core arranged along a front-to-rear direction connecting the crotch portion with the abdominal portion and the back portion; a crotch stretchable member configured to be stretchable in the front-to-rear direction and disposed closer to the skin side than the absorbent core in at least a region of the crotch portion that overlaps the absorbent core, a member in the crotch region that is closer to the skin than the absorbent core, including the crotch stretchable member, stretches to 1.1 to 1.5 times its natural state before wearing when subjected to a tensile load of 2 N / 50 mm along the front-to-rear direction; The present invention provides a pants-type absorbent article in which, when the absorbent core absorbs liquid, the crotch portion stretches at least in the front-to-back direction in accordance with the extension of the crotch stretchable member, at a member on the non-skin-facing side of the absorbent core. [Effects of the Invention]

[0007] The pants-type absorbent article of the present invention can achieve both underwear-like appearance and excellent liquid absorbency when in a state of absorbing excreted liquid while being worn. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a plan view schematically showing, from the front side, a pants-type diaper as a preferred embodiment of a pants-type wearing article according to the present invention in its natural state before being worn. [Figure 2] 2 is a plan view showing the pants-type diaper shown in FIG. 1 as seen from the skin-facing side after being torn at the side seal portion, unfolded, and stretched. FIG. [Figure 3] FIG. 3 is an enlarged cross-sectional view schematically showing a cross section taken along line III-III of the pants-type diaper in the unfolded state shown in FIG. 2. [Figure 4] FIG. 2 is an explanatory diagram showing an example (Example 1) of a crotch portion provided with a crotch stretchable member in a state before liquid absorption and in a stretched state after liquid absorption. [Figure 5] FIG. 10 is an explanatory diagram showing a schematic diagram of another example (Example 2) of a crotch portion provided with crotch stretchable members in a state before liquid absorption and in a stretched state after liquid absorption. [Figure 6] 1 is an explanatory diagram showing a state in which the pants-type diaper of the present embodiment is stretched in the front-rear direction by absorbing excreted liquid while being worn. FIG. [Figure 7] FIG. 2 is an explanatory diagram schematically illustrating an example of a state in which the outer contour of the crotch portion is maintained in a V-shape when the pants-type diaper of the present embodiment is in a liquid-absorbing state during wear. [Figure 8] 1 is a plan view showing an example of an outline (silhouette) of a pants-type diaper according to the present embodiment. [Figure 9]1 is a plan view showing an example of the outline (silhouette) of a conventional pants-type diaper. DETAILED DESCRIPTION OF THE INVENTION

[0009] A preferred embodiment of the pants-type absorbent article of the present invention will be described below with reference to the drawings. In this specification, the side that comes into contact with the wearer's skin is referred to as the skin side or inner side, and the opposite side is referred to as the non-skin side or outer side. These terms are also used to indicate the relative positional relationship in the component configuration of an absorbent article for components that do not have a surface that comes into contact with the wearer's skin. In terms of relative positional relationship, the side that is located in front of the wearer is referred to as the front side or front, and the side that is located behind is referred to as the rear side or rear. Similarly, the side that is located closer to the wearer's head is referred to as the upper side or upper, and the side that is located closer to the legs is referred to as the lower side or lower. The normal direction to the front or back surface of the worn article, i.e., the stacking direction of the components, is referred to as the thickness direction.

[0010] As shown in Fig. 1, the pants-type diaper 10 of this embodiment (hereinafter also referred to as the diaper 10) is divided into a ventral portion 10F arranged on the ventral side of the wearer, a crotch portion 10C arranged on the crotch side, and a dorsal portion 10R arranged on the dorsal side, and has a body length direction T and a width direction X perpendicular to the body length direction T. The diaper 10 also has a waist opening 12, through which the wearer's torso passes, above the ventral portion 10F and the dorsal portion 10R in the body length direction T, and a pair of leg openings 13, 13, through which the wearer's legs pass, on both the left and right sides of the crotch portion 10C.

[0011] The diaper 10 comprises, as its constituent members, an absorbent main body 1 and an exterior body 2 disposed on the non-skin-facing side of the absorbent main body 1. The exterior body 2 includes sections 21 and 22 disposed in the ventral section 10F and the dorsal section 10R. The exterior body 2 is stretchable in the width direction X to form waist gathers and improve fit around the wearer's waist. The stretchability may be achieved by forming the exterior body 2 as a stretchable sheet, or by disposing a plurality of elastic members stretched in the width direction X between two sheets of nonwoven fabric that form the exterior body. The ventral section 10F and the dorsal section 10R are joined at their opposite side edges (ends in the width direction X) to form a pair of left and right side seal sections 11, 11. The side seal sections 11 can be joined by various methods commonly used for this type of article. Examples include fusion joining (e.g., heat sealing, ultrasonic sealing, laser fusing) and pressure joining (e.g., embossing), which are used to consolidate the components.

[0012] In the diaper 10 of this embodiment, the exterior body 2 is divided into a ventral exterior body 21 and a dorsal exterior body 22, which form the outer surfaces of the ventral portion 10F and the dorsal portion 10R, respectively. The exterior body 2 is not limited to this divided form and may have any form that is commonly used for this type of article. For example, the exterior body 2 may extend over the crotch portion 10F, the crotch portion 10C, and the dorsal portion 10R, and have a shape that is narrowed inward in the width direction at the crotch portion 10C. Hereinafter, the exterior bodies 2 in the ventral portion 10F and the rear portion 10R of the diaper 10 will be described as the aforementioned divided ventral exterior body 21 and rear exterior body 22.

[0013] In the diaper 10 of this embodiment, an annular waist portion 10D consisting of a ventral exterior body 21 and a dorsal exterior body 22 is formed by joining at the side seal portions 11. The absorbent main body 1 extending from the waist portion 10D forms the crotch portion 10C. Furthermore, a crotch side extension portion 8 extending from the dorsal exterior body 22 is disposed closer to the crotch portion 10C than the position of the side seal portions 11. The crotch side extension portion 8 covers a portion of the non-skin side of the absorbent main body 1 in the crotch portion 10C and forms a portion of the outer surface main body on the buttocks side of the crotch portion 10C.

[0014] Fig. 2 shows the diaper 10 in a state where the side seal portions 11, 11 are broken, unfolded, and stretched, as viewed from the skin-facing side (hereinafter, also referred to as the unfolded state). Here, the unfolded state refers to a state where each portion is stretched to spread the pants-type absorbent article flat. The length direction T of the diaper 10 shown in Fig. 1 corresponds to the longitudinal direction Y of the diaper 10 in the unfolded state. The longitudinal direction Y is also referred to as the front-to-rear direction Y connecting the crotch portion 10C with the ventral portion 10F and the dorsal portion 10R. In the unfolded state of the diaper 10, the ventral outer body 21 and the rear outer body 22 are elongated in the width direction X. The absorbent main body 1 is elongated in the longitudinal direction Y, extending at the center of the width direction X toward the ventral portion 10F, the crotch portion 10C, and the rear portion 10R of the diaper 10. The absorbent main body 1 is bonded and fixed to at least the skin-facing sides of the ventral outer body 21 and the rear outer body 22. In the ventral outer body 21 and the rear outer body 22, the absorbent main body 1 is located closer to the crotch portion 10C than the waist opening 12. The skin-facing ends of the absorbent main body 1 in the longitudinal direction Y are covered and bonded by the folded-back portions 23 of the ventral outer body 21 and the rear outer body 22, which are arranged on the non-skin-facing side. These bonding and fixing methods can be achieved by various means commonly used in this type of article. For example, bonding and fixing may be achieved by applying various adhesives, such as hot-melt adhesives.

[0015] 2 and 3, the absorbent body 1 has a liquid-permeable topsheet 14 on the skin side, a leak-barrier sheet 15 on the non-skin side, and a liquid-retaining absorber 16 disposed between the topsheet 14 and the leak-barrier sheet 15. The absorber 16 includes an absorbent core 16A, which is a liquid-retaining main body, and is arranged along the front-to-back direction Y connecting the crotch portion 10C with the ventral portion 10F and the back portion 10R. In this embodiment, the absorbent core 16A is shown as a mixed stack of superabsorbent polymer material and hydrophilic fibers, and the outer surface of this absorbent core 16A is covered with a core wrap sheet 16B to form the absorber 16. The superabsorbent polymer material referred to here is a surface-crosslinked polymer material known as SAP (Superabsorbent Polymer). The absorbent core 16A is not limited to the mixed fiber stack described above, and can have various configurations that can serve as a liquid-retaining body in this type of article. For example, the absorbent core 16A may be made of a superabsorbent polymer material without containing hydrophilic fibers. In this case, the absorbent body 16 can be composed of an absorbent sheet in which a layer of superabsorbent polymer material is sandwiched and fixed between multiple hydrophilic base sheets (absorbent paper or nonwoven fabric), and the core wrap sheet 16B described above can be omitted. The absorbent sheet can be folded or stacked, for example, to appropriately adjust the basis weight of the superabsorbent polymer in part or the entire absorbent body 16. When forming this absorbent sheet, the superabsorbent polymer material can be integrated with the base sheet by utilizing the adhesive strength that the superabsorbent polymer material develops when wetted or by using a binder such as an adhesive or adhesive fiber added separately. Examples include those described in paragraphs

[0019] to

[0127] of Japanese Patent No. 2963647 and those described in paragraphs

[0020] to

[0075] of Japanese Patent No. 2955223. The absorbent sheet can be produced by a variety of commonly used methods, including wet and dry methods. The absorbent sheet has a thickness of 3.0 mm or less, and the highly absorbent polymer material is dispersed in the planar direction of the sheet, making it less susceptible to gel blocking and providing high absorbency. Examples include those described in paragraphs

[0019] to

[0131] of Japanese Patent Laid-Open No. 8-246395.

[0016] The absorbent main body 1 further comprises a pair of side sheets 17 on both sides in the longitudinal direction Y. Leg gather elastic members 18 are arranged at the outer ends of the side sheets 17 in the width direction X so as to be stretchable along the longitudinal direction Y, thereby forming leg gathers around the leg openings 13. In addition, three-dimensional gather elastic members 19 are arranged at the inner ends of the side sheets 17 in the width direction X so as to be stretchable along the longitudinal direction Y, thereby forming three-dimensional gathers.

[0017] Next, the crotch portion 10C of the diaper 10 will be described. As shown in FIG. 2, the crotch portion 10C is located between an imaginary line L1 connecting the lower edges of a pair of side seal portions 11, 11 in the width direction X on the abdominal portion 10F and an imaginary line L2 connecting the lower edges of a pair of side seal portions 11, 11 in the width direction X on the back portion 10R. The crotch portion 10C includes a fold line CL along the width direction X that divides the front and back of the diaper 10 in half. A portion of the crotch portion 10C located in front of the fold line CL (front crotch portion) CF is connected to the abdominal portion 10F, and a portion of the crotch portion 10C located behind the fold line CL (rear crotch portion) CR is connected to the back portion 10R. The fold line CL is the outer edge located at the lower end of the crotch portion 10C in the body length direction T when the side seal portions 11 are in pants form before being torn.

[0018] The crotch section 10C further includes a crotch main absorbent region C1, which covers the wearer's urination point and directly receives excretory fluid, potentially absorbing more fluid than other regions, and a crotch auxiliary absorbent region C2 located closer to the back. The crotch main absorbent region C1 is located closer to the front of the crotch section 10C and preferably extends from the imaginary line L1 at the lower end of the abdominal section 10F to the area beyond the fold line CL, i.e., the combined area of ​​the front crotch section CF and a portion of the back crotch section CR. Specifically, the ratio (H2 / H1) of the length H2 of the crotch main absorbent region C1 in the front-to-back direction Y to the length H1 of the crotch section 10C in the front-to-back direction Y is preferably 0.4 or greater, more preferably 0.6 or greater. Furthermore, the ratio (H2 / H1) is preferably 1.0 or less, more preferably 0.8 or less. Typically, the crotch main absorbent region C1 is preferably located further forward than the crotch extensions 8. That is, the crotch main absorbent region C1 is preferably a region between an imaginary line L1 located at the lower end of the abdominal portion 10F and an imaginary line L3 along the width direction X located at the crotch side edge of the crotch extension portion 8.

[0019] The absorbent core 16A in the crotch main absorbent region C1 is narrower than the widest portions of the absorbent core 16A in the ventral and dorsal portions 10F, 10R in a plan view in the unfolded state as shown in Fig. 2. As a result, the absorbent body 16 in the crotch main absorbent region C1 includes regions 16C on both sides of the absorbent core 16A in the width direction X where the absorbent core 16A is not disposed, as shown in Fig. 3. It is preferable that these regions 16C are disposed over the entire area of ​​the crotch main absorbent region C1 in the front-to-rear direction Y.

[0020] The diaper 10 of this embodiment has the following configurations (A) to (C) in the crotch portion 10C. (A) At least in the region of the crotch portion 10C overlapping the absorbent core 16A, a crotch stretchable member 31 is provided that is stretchable in the front-to-back direction Y and is disposed closer to the skin than the absorbent core 16A. (B) The components in the crotch region 10C on the non-skin-facing side of the absorbent core 16A, including the crotch stretchable member 31, stretch to between 1.1 and 1.5 times their natural state before wearing when subjected to a tensile load of 2N / 50mm along the front-to-back direction Y. (C) In the crotch portion 10C, when the absorbent core 16A absorbs liquid, the members on the non-skin facing side of the absorbent core 16A stretch at least in the front-to-back direction Y as the crotch stretchable members 31 stretch.

[0021] In the diaper 10 having the above-described configurations (A) to (C), the components of the crotch region 10C that are closer to the skin than the absorbent core 16A suitably stretch at least in the front-to-back direction Y in response to the stretch of the crotch stretchable member 31. This allows the spaces between the swelling superabsorbent polymer materials in the absorbent core 16A of the crotch region 10C to be widened, thereby mitigating swelling inhibition (gel blocking), improving liquid absorption efficiency and maintaining liquid absorbency. Furthermore, this suitable stretch in the front-to-back direction Y also allows the volumetric expansion pressure of the absorbent core 16A due to the swelling of the superabsorbent polymer materials to be dispersed in the front-to-back direction Y of the diaper 10, thereby reducing downward sagging of the crotch region 10C. This prevents the entire crotch region 10C from expanding and sagging, allowing both sides of the crotch region 10C to fit easily along the line of the wearer's groin, and maintaining the V-shaped external contour of the crotch region 10C. This allows the external outline of the diaper 10 when worn, as viewed from the front, to look like underwear. In this way, the diaper 10 of this embodiment can achieve both underwear-like appearance and excellent liquid absorbency when in a state of absorbing excreted liquid during wear.

[0022] The above configurations (A) to (C) will be described in detail below.

[0023] First, the configuration (A) will be described. 3, the crotch portion 10C includes crotch stretchable members 31 configured to be stretchable in the front-to-back direction Y on the non-skin-facing side of the absorbent core 16A at least in the region overlapping the absorbent core 16A. Of the multiple members arranged on the non-skin-facing side of the absorbent core 16A, some or all of the members may be crotch stretchable members 31.

[0024] The range in which the crotch stretchable members 31 are disposed in the front-to-rear direction Y can be appropriately set as a region in which the above-mentioned effects can be effectively exerted. For example, it is preferable that the crotch stretchable member 31 extends in the front-to-rear direction Y to the extent that the absorbent main body 1 overlaps with the exterior body 2 (ventral exterior body 21 and rear exterior body 22). In this case, it is preferable that the end of the crotch stretchable member 31 in the front-to-rear direction Y is located closer to the crotch region 10C than imaginary lines L1 and L2 (see FIG. 2) in the width direction X that are located at the lower ends of the side seal portions 11. This allows the ventral exterior body 21 and rear exterior body 22 to be connected with an appropriate contractile force, making the V-shaped appearance more distinct during wear and allowing the garment to assume a shape that is more like underwear. In addition, the length of the crotch stretchable members 31 in the front-to-back direction Y is preferably shorter than the length of the absorbent core 16A in the front-to-back direction Y. This prevents the stretching force of the crotch stretchable members 31 from reaching the end portions of the absorber 16, including the absorbent core 16A, in the longitudinal direction Y, thereby preventing the entire absorber 16 from shrinking. This also prevents the diaper 10 from wrinkling as a result of the entire absorber 16 shrinking, thereby preventing the diaper 10 from becoming thicker. This also prevents the appearance from being adversely affected by areas where the shrinkage disappears coinciding with areas where the absorber 16 is absent. As a result, the underwear-like appearance of the diaper 10 can be more effectively maintained. At the same time, the liquid retention performance of the absorber 16 can be more effectively exhibited. The length of the crotch stretchable members 31 in the width direction X may be the same as or longer than the length of the absorbent core 16A in the width direction X, and can be appropriately set to more effectively exhibit the effects described below. A preferred range of the length in the width direction X will be described later.

[0025] 3, the crotch stretchable member 31 is shown as a member laminated on the non-skin-facing side of the leak-barrier sheet 15. Furthermore, in Example 1, an outer layer sheet 41 is disposed on the non-skin-facing side of the crotch stretchable member 31. In Example 1, as shown in FIG. 4, the crotch stretchable members 31 are joined and fixed in a stretched state along the front-to-back direction Y and are arranged in a contracted state in a natural state. The "natural state" here refers to the state in which the diaper 10 is left unworn for a predetermined period of time. Specifically, for an unused diaper 10 immediately removed from a retail package, the waist portion 10D is stretched outward in the width direction X between the side seal portions 11, 11, and this stretched state is maintained for 15 seconds. The tension on the diaper 10 is then released, and the diaper 10 is placed flat on a surface such as a desk for 5 minutes, after which the natural state is defined as the state of the diaper 10. This definition also applies to the term "natural state" used elsewhere in this specification.

[0026] In Example 1, the core wrap sheet 16B, the leakproof sheet 15, and the outer layer sheet 41 on the non-skin-facing side other than the crotch stretchable member 31, which are arranged on the non-skin-facing side of the absorbent core, form gathers in their natural state as the crotch stretchable member 31 contracts. The above members other than the crotch stretchable member 31 are stretchable in the front-to-back direction Y by the amount of the gathers. In this way, the crotch stretchable member 31 and the above members other than it are configured to be stretchable in the front-to-back direction Y on the non-skin-facing side of the absorbent core 16A as the crotch stretchable member 31 stretches.

[0027] In the above Example 1, instead of using the crotch stretchable member 31 as the member interposed between the leakproof sheet 15 and the outer layer sheet 41, at least one of the non-skin-facing core wrap sheet 16B, the leakproof sheet 15, and the outer layer sheet 41 may be formed of the crotch stretchable member 31. Alternatively, a member may be interposed between the leakproof sheet 15 and the absorbent body 16, and this member may be the crotch stretchable member 31. A member may be interposed inside the absorbent body 16 between the absorbent core 16A and the non-skin-facing core wrap sheet 16B, and this member may be the crotch stretchable member 31. It is particularly preferable to configure the crotch stretchable member 31 as the outer layer sheet 41 closest to the skin in the crotch region 10C. In this case, the outer layer sheet 41 made of the crotch stretchable member 31 is joined and fixed in a stretched state along the front-to-back direction Y, and is contracted in its natural state. This reduces the likelihood of gathering on the outer surface of the crotch portion 10C of the diaper 10, resulting in a more underwear-like appearance. Also, the thickness of the diaper 10 can be further reduced, resulting in a neater appearance.

[0028] Various materials capable of being stretched as described above can be used as the crotch stretchable member 31. For example, the crotch stretchable member 31 may be a sheet-like member or may be made of a string-like or thread-like elastic member. Using a sheet-like member is preferable because it reduces unevenness in the stretch of the crotch portion 10C in the front-to-back direction Y. Examples of the sheet-like crotch stretch member 31 include a sheet obtained by sandwiching an elastic filament between two fiber sheets and then groove-stretching the filament, as described in paragraphs

[0012] to

[0085] of JP 2008-179128 A and

[0013] to

[0051] of JP 2007-22066 A, a stretch film as described in paragraph

[0079] of JP 2019-103889 A, and a polyurethane film. The string-like or thread-like elastic member may be placed directly in the crotch portion 10C to form the crotch stretchable member 31, or multiple strings may be joined and fixed between multiple sheets in a stretched state to form the crotch stretchable member 31. The crotch stretchable member 31 may include either the sheet-like member or the string-like or thread-like elastic member, either alone or in combination.

[0029] When the crotch stretchable member 31 is configured with the above-mentioned string- or thread-like elastic member, it is preferable that the string- or thread-like elastic member extend in the front-to-rear direction Y and be arranged in multiple numbers in the width direction X. In this case, the length of the crotch stretchable member 31 in the width direction X is the width (length) of the area where multiple string- or thread-like elastic members are arranged in the width direction X. When the crotch stretchable member 31 is made of a string-like or thread-like elastic member, the gathering of the crotch portion 10C is more easily visible than when it is made of a sheet-like member, which is preferable because it allows the user to easily recognize the stretchability of the crotch portion 10C in the front-to-back direction Y. Furthermore, if the crotch stretchable members 31 are made of the above-mentioned string-like or thread-like elastic members, it is possible to reduce the amount of material used compared to when they are made of sheet-like members. In this case, the crotch region 10C can be made thinner and softer, and not only the appearance but also the feel of the diaper 10 can be made more similar to underwear. Furthermore, the stretchability of the string-like or thread-like elastic member in the front-to-rear direction Y can be appropriately set by adjusting the thickness and pitch in the width direction X. This also makes it possible to divide the garment into regions in the width direction X and appropriately vary the stretchability in the front-to-rear direction Y for each divided region.

[0030] FIG. 5 shows an embodiment (Example 2) different from Example 1 above. In Example 2 shown in FIG. 5, the core wrap sheet 16B, the leak barrier sheet 15, and the outer layer sheet 41, which are closer to the skin than the absorbent core 16A, are stretchable. That is, the core wrap sheet 16B, the leak barrier sheet 15, and the outer layer sheet 41 as a whole form the crotch stretchable member 31. In Example 2, the stretchable core wrap sheet 16B, the leak barrier sheet 15, and the outer layer sheet 41 are joined and fixed to the diaper 10 without being stretched. That is, they are arranged in a contracted state in their natural state. As a result, the core wrap sheet 16B, the leak barrier sheet 15, and the outer layer sheet 41 are in a contracted state in their natural state without forming gathers. In this way, in Example 2 as well, the crotch region 10C is configured to be stretchable in the front-to-back direction Y on the closer to the skin than the absorbent core 16A. In addition, the formation of gathers on the closer to the skin than the crotch region 10C is suppressed, resulting in a more underwear-like appearance.

[0031] The stretchable core wrap sheet 16B, the leak-proof sheet 15, and the outer layer sheet 41 in Example 2 can be made of the same material as the sheet-like crotch stretch member 31 in Example 1. In addition to these, stretchable moisture-permeable films and the like can also be used.

[0032] Next, the configuration (B) will be described. As mentioned above, the components in the crotch area 10C that are closer to the skin than the absorbent core 16A, including the crotch stretchable member 31, stretch to between 1.1 and 1.5 times their natural state before wearing when subjected to a tensile load of 2N / 50mm along the front-to-back direction Y. The term "at a tensile load of 2 N / 50 mm" refers to a load equivalent to the static friction force of the waist outer casing. The elongation ratio (elongation ratio from the natural state) of 1.1 to 1.5 times at a tensile load of 2 N / 50 mm refers to an elongation ratio along the front-to-back direction Y that ensures sufficient space for efficient liquid absorption and prevents sagging and slippage in the crotch region 10C of the diaper 10. The term "components on the non-skin-facing side of the absorbent core 16A" refers to all components in the crotch region 10C that are located on the non-skin-facing side of the absorbent core 16A, including the crotch stretchable member 31. The elongation ratio can be measured by the following method using all of these components cut out from the crotch region of the diaper 10.

[0033] (Method for measuring the elongation rate from the natural state of the members in the crotch region 10C, including the crotch stretchable member 31, that are closer to the skin than the absorbent core 16A, when a tensile load of 2N / 50mm is applied along the front-to-back direction Y) (1) Cut a sample in the center of the width direction X of the crotch main absorbent region C1 (see Figure 2) on the side closest to the skin than the absorbent core 16A, so that it is 50 mm in the width direction X and 100 mm in the front-to-back direction Y plus the zipper gripping width. (2) Grasp the front and rear ends of the sample so that the distance between the chucks is 100 mm, and pull with a force of 2 N. (3) Measure the distance between the zippers when pulled with a force of 2 N and calculate the elongation rate.

[0034] The elongation ratio at a tensile load of 2 N / 50 mm along the front-to-rear direction Y is preferably 1.1 times or more, and more preferably 1.2 times or more, from the viewpoint of improving liquid absorption efficiency. Moreover, the elongation ratio at a tensile load of 2 N / 50 mm along the front-to-rear direction Y is preferably 1.5 times or less, and more preferably 1.45 times or less, from the viewpoint of preventing sagging and slipping off. The stretch rate can be appropriately set by the stretch rate and arrangement range of the crotch stretchable members 31 in the front-to-back direction Y, the number of layers of members on the non-skin-facing side of the absorbent core 16A, and the like.

[0035] With the configurations (A) and (B) described above, when the absorbent core 16A of the crotch region 10C absorbs liquid, the members on the non-skin-facing side of the absorbent core 16A stretch appropriately at least in the front-to-back direction Y in accordance with the stretch of the crotch stretchable member 31. That is, the configuration described above is (C). This allows the crotch portion 10C to stretch appropriately in the front-to-back direction Y in response to the volumetric expansion pressure caused by the absorption of excrement, ensuring swelling space between the superabsorbent polymer materials and improving liquid absorption efficiency. This stretching, achieved by combining the configurations (A) to (C) above, does not simply droop in the crotch portion 10C, but can also involve moderate lifting of the ventral portion 10F and the dorsal portion 10R of the crotch portion 10C. Furthermore, because stretching in the front-to-back direction Y occurs primarily in the non-skin-facing member of the absorbent core 16A, the absorbent core 16A itself is less likely to shrink, and is more likely to have better liquid absorption and shape retention. As a result, as shown in Fig. 6, the diaper 10 can distribute the volumetric swelling pressure of the absorbent core 16A in the front-to-rear direction Y, thereby preventing excessive downward sagging or slippage of the crotch portion 10C. In other words, when the diaper 10 is worn and absorbing excreted liquid, it can achieve both an underwear-like appearance and excellent liquid absorbency.

[0036] In the diaper 10, the configuration (C) is preferably as follows. That is, the crotch portion 10 includes a widthwise central region C11 and widthwise side regions C12 (see FIG. 3), and it is preferable that the elongation rate E1 in the front-to-back direction Y of the widthwise central region C11 is greater than the elongation rate E2 in the front-to-back direction Y of the widthwise side regions C12.

[0037] The "widthwise central region C11" and the "widthwise side regions C12" on both sides thereof are preferably regions obtained by dividing the crotch portion 10C of the diaper 10 in an unfolded state into three equal parts in the width direction X ((W1) / 3=W3=W2=W3) as shown in FIG. 3. These three divisions are preferably made along the fold line CL. If the length of the crotch portion 10C in the width direction X is not uniform in the front-to-back direction Y, it is preferable that the "widthwise central region C11" divided along the fold line CL be constant in the front-to-back direction Y, and the remaining parts be the "widthwise side regions C12" on both sides. It is preferable that the configuration in which the "widthwise central region C11" and the "widthwise side regions C12" on both sides are divided into three equal parts in the width direction X is satisfied at least in the crotch main absorbent region C1. The difference in elongation rate between the widthwise central region C11 and the widthwise side region C12 can be appropriately set by the basis weight of the superabsorbent polymer material, the length in the width direction X of the absorbent core 16A containing the superabsorbent polymer material, the length in the width direction X of the crotch stretch member 31, and the number of layers and basis weight of the members on the non-skin-facing side of the absorbent core 16A.

[0038] The difference in elongation rates allows the widthwise central region C11, which includes the wearer's excretion point and absorbs a relatively large amount of liquid, to have a higher elongation rate than the widthwise side regions C12, which absorb a relatively smaller amount of liquid. The widthwise central region C11 is more elongated than the widthwise side regions C12, achieving a higher liquid absorption efficiency. This high liquid absorption efficiency can also suppress liquid diffusion from the widthwise central region C11 to the widthwise side regions C12, thereby suppressing volumetric expansion of the widthwise side regions C12. This further accentuates the difference in elongation rates. Additionally, by making the widthwise side regions C12 less elongated than the widthwise central region C11, the liquid absorption efficiency is improved to some extent while also exerting stress against the volumetric expansion pressure of the absorbent core 16A. This allows the crotch region 10C to have a clean, V-shaped outline when the diaper 10 has absorbed excreted liquid, helping to maintain an underwear-like appearance. At the same time, the liquid absorption performance is improved.

[0039] More details are as follows. That is, by increasing the elongation rate of the widthwise central region C11, which absorbs a relatively large amount of liquid, sufficient swelling space can be secured between the superabsorbent polymer materials. This allows the widthwise central region C11 to function as the primary liquid-absorbing functional area, and effectively suppresses liquid absorption and the associated volumetric expansion in the adjacent widthwise side regions C12. Meanwhile, the widthwise side regions C12 are more susceptible to contraction than the widthwise central region C11, and can maintain a sufficient level of stress after absorbing liquid so as not to impair fit around the wearer's groin area. This functional division and cooperation between the widthwise central region C11 and the widthwise side regions C12 allows the diaper 10 to maintain a V-shaped external shape in the crotch region 10C even when absorbing excreted liquid during wear (see FIG. 7). This cooperative effect is particularly noticeable in the crotch main absorbent region C1 near the front, and it allows the outer contour of the diaper 10 when worn to look more like underwear when viewed from the front while improving liquid absorbency.

[0040] To make the above-mentioned effect more effective, the extensibility E1 of the widthwise central region C11 in the front-rear direction Y is preferably 1.1 times or more, more preferably 1.15 times or more, the extensibility E2 of the widthwise side regions C12 in the front-rear direction Y. In addition, from the viewpoint of achieving more appropriate elongation in the widthwise side regions C12, the elongation rate E1 in the front-to-back direction Y of the widthwise central region C11 is preferably 1.3 times or less, and more preferably 1.25 times or less, the elongation rate E2 in the front-to-back direction Y of the widthwise side regions C12.

[0041] From the viewpoint of reflecting the difference in liquid absorption capacity in the difference in elongation rate, it is preferable that the widthwise side regions C12 include the end portions of the absorbent body 16 in the width direction X and the end portions of the absorbent core 16A in the width direction X. In other words, it is preferable that the widthwise side regions C12 include the aforementioned regions 16C where the absorbent core 16A is not disposed. The preferred range of the length in the width direction X of the absorbent core 16A will be described later.

[0042] (Method for measuring elongation rate of widthwise central region C11 and widthwise side region C12) (1) The left and right side seal portions 11 of the diaper 10 are ripped to lay the diaper 10 flat. The leg gather elastic members 18 and the three-dimensional gather elastic members 19 are removed with scissors or the like. The elastic members of the waist portion 10D are not removed. (2) Measurement scales (marks) are provided at equal intervals in the front-to-back direction Y on the outermost layer of the non-skin-facing side of the crotch portion 10C of the diaper 10. A plurality of such scales are provided at equal intervals in the front-to-back direction Y at the center of the width direction X of the crotch portion 10C and at portions corresponding to the left and right side edges (edges in the width direction X) of the absorbent body 16. The center of the width direction X of the crotch portion 10C is the measurement position for the elongation rate of the widthwise central region C11, and the left and right side edges of the absorbent body 16 are the measurement positions for the elongation rate of the widthwise side regions C12. (3) Inject 120 g of 5% saline into the skin-facing side of the diaper 10, aiming for the intersection of the fold line CL and the center line ML in the width direction X. The injection time is not important. It is preferable to use a funnel (with an injection point of approximately 20 mm diameter) to determine the injection point. After the entire liquid has been injected, let it sit for 5 minutes. (4) After leaving the diaper 10 for 5 minutes, the skin side of the diaper 10 is turned up, and the upper and lower ends of the ventral portion 10F and the back portion 10R of the diaper 10 are fixed to the support rods with clips or the like, and the support rods are raised to the same height so that the crotch portion 10C of the diaper 10 does not contact the bottom surface. The spacing between the support rods of the ventral portion 10F and the back portion 10R is 60 to 70 percent of the total length of the diaper 10 in the longitudinal direction Y when unfolded, for example, approximately 150 to 250 mm. (5) At the center of the crotch portion 10C in the width direction X where the graduations are marked in (2) above, and at the portions corresponding to the left and right side edges (edges in the width direction X) of the absorbent body 16, the graduations before the saline solution is poured are compared with the graduations after the saline solution is poured to achieve the state described in (4) above, and the elongation percentage is calculated based on the following formula (1). In this case, the elongation percentage may be calculated for each graduation interval, or the elongation percentage may be calculated based on the graduations of the entire crotch portion 10C of the diaper 10. Elongation rate (%) = {(length after stretching - length before stretching) / length before stretching} x 100 (1)

[0043] From the viewpoint of more suitably realizing the difference in the aforementioned elongation rates, when the crotch stretchable member 31 is arranged overlapping the widthwise central region C11 and the widthwise side regions C12 that divide the crotch portion 10C in the width direction X, and is configured to include the aforementioned string-like or thread-like elastic member, it is preferable that the diameter of the string-like or thread-like elastic member arranged in the widthwise side region C12 be larger than the diameter of the string-like or thread-like elastic member arranged in the widthwise central region C11. Specifically, the difference (R1-R2) between the diameter (R1) of the string- or thread-like elastic member arranged in the widthwise side region C12 and the diameter (R2) of the string- or thread-like elastic member arranged in the widthwise central region C11 is preferably 300 dtex or more. The difference (R1-R2) is preferably 600 dtex or less, from the viewpoint of preventing twisting of the product due to a sudden difference in stress.

[0044] From a similar viewpoint, when the crotch stretchable member 31 is arranged overlapping the widthwise central region C11 and widthwise side regions C12 that divide the crotch portion 10C in the width direction X, and is configured to include the aforementioned string-like or thread-like elastic member, it is preferable that the pitch of the string-like or thread-like elastic member arranged in the widthwise side region C12 is narrower than the pitch of the string-like or thread-like elastic member arranged in the widthwise central region C11. Specifically, the difference (P2-P1) between the pitch (P2) of the string- or thread-like elastic members arranged in the widthwise central region C11 and the pitch (P1) of the string- or thread-like elastic members arranged in the widthwise side region C12 is preferably 2 mm or more, more preferably 4 mm or more, and even more preferably 6 mm or more. From the viewpoint of preventing distortion of the product due to a sudden difference in stress, the difference (P2-P1) is preferably 20 mm or less, more preferably 15 mm or less, and even more preferably 10 mm or less.

[0045] The absorbent core 16A containing a highly absorbent polymer material that swells upon absorbing liquid is preferably arranged in the crotch portion 10C as follows. 3, the ratio (K2 / W1) of the length K2 of the absorbent core 16A in the crotch portion 10C in the width direction X to the length W1 of the crotch portion 10C in the width direction X is preferably 0.40 or more, more preferably 0.45 or more, and even more preferably 0.50 or more, from the viewpoints of maintaining excellent liquid absorbency in the crotch portion 10C and of achieving appropriate elongation in the width direction side regions C12. Furthermore, the ratio (K2 / W1) is preferably 0.70 or less, more preferably 0.65 or less, and even more preferably 0.60 or less, from the viewpoint of suitably suppressing the elongation rate in the front-to-rear direction Y in the width direction side regions C12. Furthermore, from the same viewpoint as above, the ratio (K5 / W3) of the length K5 (=(K2-K4) / 2) in the width direction X of the absorbent core 16A arranged in the width direction side region C12 to the length W3 (=(W1) / 3) in the width direction X of the width direction side region C12 is preferably 0 or more, more preferably 0.1 or more, and even more preferably 0.2 or more. Moreover, from the same viewpoint as above, the ratio (K5 / W3) is preferably 0.5 or less, more preferably 0.4 or less, and even more preferably 0.3 or less.

[0046] The above ratios (K2 / W1) and (K5 / W3) are preferably satisfied at least along the fold line CL, more preferably in the crotch main absorbent region C1, and even more preferably in the entire crotch portion 10C.

[0047] In FIG. 3, the length in the width direction X of the crotch stretchable member 31 is longer than the length K1 in the width direction X of the absorber 16 on the fold line at the lower end of the crotch portion 10C in the length direction T, but is not limited to this. For example, the length in the width direction X of the crotch stretchable members 31 on the folding line is preferably the same as the length K2 of the absorbent core 16A in the width direction X, or longer than the length K2 of the absorbent core 16A in the width direction X and shorter than the length K1 of the absorber 16 in the width direction X. It is more preferable that the length in the width direction X of the crotch stretchable members 31 be longer than the length K2 of the absorbent core 16A in the width direction X and shorter than the length K1 of the absorber 16 in the width direction X. This arrangement allows the crotch stretchable members 31 to overlap the region 16C (region with length K3 in the width direction X) where the absorbent core 16A is not located within the length K1 of the absorber 16. In the portions where the crotch stretchable members 31 overlap the region 16C where the absorbent core 16A is not located, the pressure due to swelling of the superabsorbent polymer material, which is the driving force for elongation, is reduced. This allows the width direction side regions C12 to exhibit contractility with lower elongation than the width direction central region C11. Furthermore, the length in the width direction X of the crotch stretchable members 31 may be equal to or greater than the length K1 in the width direction X of the absorber 16 at the bifold line at the lower end of the crotch portion 10C in the length direction T. This allows for a clearer difference in the elongation rate between the widthwise central region C11 and the widthwise side regions C12. Furthermore, when the diaper 10 is in a liquid-absorbing state while being worn, a contracting force acts more easily on the outer side of the absorber 16 in the widthwise side regions C12 than in the widthwise central region C11, thereby enabling the diaper 10 to more clearly maintain a tight fit around the wearer's groin even after absorbing liquid. The length of these crotch stretchable members 31 in the width direction X is preferably sufficient at least on the two-fold line CL, more preferably in the crotch main absorbent region C1, and even more preferably in the entire crotch portion 10C.

[0048] By including the crotch stretch member 31 in the crotch portion 10C within the above-mentioned arrangement range and making the difference in elongation rate between the widthwise central region C11 and the widthwise side region C12 more clear, the V-shaped outer contour of the crotch portion 10C can be better maintained when the diaper 10 is in a state of absorbing excreted liquid while being worn.

[0049] When the absorbent core 16A is a mixed stack of superabsorbent polymer material and hydrophilic fibers as described above, the ratio of the mass content of the hydrophilic fibers to the mass content of the superabsorbent polymer material (former / latter) is more than 0 mass% and less than 100 mass%. It is preferable that the mass content of the superabsorbent polymer material, which acts as a driving force for elongation, be as high as possible. From this perspective, the ratio (former / latter) is preferably 0.5 mass% or less, and more preferably 0.2 mass% or less.

[0050] Furthermore, the absorbent core 16A is preferably made of a superabsorbent polymer material and does not contain hydrophilic fibers, so as not to inhibit the swelling of the superabsorbent polymer material, which is the driving force for elongation. Furthermore, the absence of hydrophilic fibers allows for greater contraction of the diaper 10 before wearing, and allows for a greater difference in elongation between the widthwise central region C11 and the widthwise side regions C12 when the diaper 10 is in a liquid-absorbed state during wear. This is preferable because it provides a more distinct V-shaped contour in the crotch portion 10C.

[0051] Furthermore, it is preferable that the absorbent core 16A does not include grooves extending in the front-to-back direction Y, at least in the crotch portion 10C. These grooves refer to areas that are free of absorbent material containing superabsorbent polymer, such as slits, or areas with a lower basis weight. By not including such grooves, the absorbent core 16A does not include areas where swelling of the superabsorbent polymer material, which is the driving force for elongation, does not occur, thereby preventing uneven pressure and the resulting uneven elongation.

[0052] The highly absorbent polymer material contained in the absorbent core 16A preferably has an absorption capacity of 15 g / g or more under a pressure of 2 kPa, in order to more suitably facilitate the exertion of the extensibility of the non-skin-facing member of the absorbent core 16A. This allows for a high absorbent capacity and favorable elongation of the crotch portion 10C, driven by swelling, and simultaneously allows the space between the superabsorbent polymer materials to expand rapidly and in a timely manner in response to the swelling speed of the superabsorbent polymer.

[0053] The "absorption capacity under a pressure of 2 kPa" is approximately equivalent to the body pressure applied to the absorbent body 16 when the diaper 10 is worn. The "absorption capacity under a pressure of 2 kPa" is a measure of the maximum absorption capacity of the superabsorbent polymer material when pressure is applied to the absorbent body 16 by wearing the diaper 10. A larger value indicates a larger absorption capacity of the superabsorbent polymer material under pressure while wearing the diaper 10, and indicates a higher swelling pressure. The absorption capacity under a pressure of 2 kPa is expressed as an amount converted into physiological saline solution, and is measured, for example, by the following method.

[0054] (Method for measuring absorption capacity under 2 kPa pressure) The absorption capacity under a pressure of 2 kPa is measured as follows. A column is prepared by attaching a mesh (250 mesh) to the bottom opening of a vertically standing cylinder (inner diameter 30 mm). 0.500 g of superabsorbent polymer material (particles) is placed into the column to a uniform thickness. Next, a weight (capable of applying a pressure of 2.0 kPa) with an outer diameter slightly smaller than 30 mm is placed on top of the superabsorbent polymer material. Next, 100 mL of saline (0.9% by mass sodium chloride solution) is poured into a 100 mL beaker, and the column is immersed in the saline so that the mesh does not touch the bottom of the beaker, and left in this state for 1 hour. The column is then removed from the beaker and allowed to drain for 15 minutes with a weight placed on the superabsorbent polymer material. Then, the absorption capacity under pressure is calculated according to the following formula (2).

[0055] Absorption capacity under 2 kPa pressure (g / g) = [(total mass) - (column mass) - (mass of superabsorbent polymer material) - (mass of weight)] / (mass of superabsorbent polymer material) (2)

[0056] The absorption capacity of the highly absorbent polymer material under a pressure of 2 kPa is preferably 15 g / g or more, and more preferably 20 g / g or more, from the viewpoint of increasing the liquid absorption capacity and enhancing the driving force for elongation. The absorption capacity of the superabsorbent polymer material under a pressure of 2 kPa is preferably 50 g / g or less, more preferably 40 g / g or less, and even more preferably 30 g / g or less, from the viewpoint of preventing gel blocking due to excessive swelling.

[0057] The basis weight of the high-absorbent polymer material in the crotch portion 10C is set to 100 g / m from the viewpoint of increasing the liquid absorption capacity of the absorbent core 16A to improve the liquid absorption property and from the viewpoint of making the function as a driving force for elongation more effective. 2 More than 150g / m 2 More preferably, 200 g / m 2 The above is more preferable. The basis weight of the highly absorbent polymer material in the crotch area 10C is set to 500 g / m2 from the viewpoint of preventing gel blocking due to excessive swelling. 2 Preferably less than 450 g / m 2 Less than 400 g / m is more preferable. 2 The following is even more preferred:

[0058] Furthermore, it is preferable that the basis weight of the superabsorbent polymer material in the crotch portion 10C be within the following range. That is, as shown in Figure 3, the ratio (Q2 / Q1) of the basis weight Q2 of the superabsorbent polymer material in the widthwise side region C12 to the basis weight Q1 of the superabsorbent polymer material in the widthwise central region C11 is preferably 0.5 or less, more preferably 0.4 or less, and even more preferably 0.3 or less, in order to make the difference in elongation rate mentioned above more clear. In order to improve the liquid absorbency of the widthwise side region C12 under low elongation conditions, the ratio (Q2 / Q1) is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.25 or more.

[0059] The basis weight Q1 of the superabsorbent polymer material in the widthwise central region C11 is 150 g / m 2 More than 200g / m 2 More preferably, 250 g / m 2 The above is more preferable. The basis weight Q1 of the superabsorbent polymer material in the widthwise central region C11 is set to 500 g / m 2 Preferably less than 450 g / m 2 Less than 400 g / m is more preferable. 2 The following is even more preferred:

[0060] The basis weight Q2 of the highly absorbent polymer material in the widthwise side region C12 is 50 g / m 2 More than 75g / m 2 More preferably, 100 g / m 2 The above is more preferable. In addition, the basis weight Q2 of the high-absorbent polymer material in the widthwise side region C12 is set to 200 g / m 2 Less than 175 g / m 2 Less than 150 g / m is more preferable. 2 The following is even more preferred:

[0061] 2 and 3, the absorber 16 preferably has absorber elastic members 161 bonded and fixed in a stretched state in the front-to-back direction Y on both sides of the absorbent core 16A. This relatively increases stress in the widthwise side regions C12, suppressing their stretchability, thereby increasing the contractile force in the front-to-back direction Y and more effectively maintaining the V-shaped outline of the diaper 10 when it absorbs liquid during wear. When the absorber 16 is made of the aforementioned absorbent sheet, the absorber elastic members 161 can be bonded and fixed on either the skin-facing or non-skin-facing side of the absorbent sheet on both sides.

[0062] From a similar perspective, the diaper 10 preferably includes side elastic members 111 that connect the front-to-rear direction Y ends of the crotch region 10C of the diaper 10 to the side seals 11, as shown in Fig. 2. The side elastic members 111 preferably connect the side seals 11 of the ventral outer body 21 constituting the ventral portion 10F and the back outer body 22 constituting the back portion 10R to the front-to-rear direction Y ends of both side regions of the crotch elastic member 31 in the crotch region 10C. This increases the contractile force in the front-to-rear direction Y in the widthwise side regions C12, thereby pulling the diaper 10 upward and more effectively maintaining the V-shaped outer contour of the diaper 10 when it is in a liquid-absorbing state during wear. The side elastic members 111 do not need to be in direct contact with the crotch elastic member 31 as long as they can perform the above-mentioned function. Preferably, they are positioned so as to overlap the crotch elastic member 31 in a plan view. The overlap between the side elastic members 111 and the crotch stretchable members 31 is preferably in a range outward in the width direction X from the region 16C in the widthwise side region C12 where the absorbent core 16A is not disposed, and more preferably outward from the absorber 16. This allows the elastic contractile force of the side elastic members 111 to be more effectively applied to the crotch stretchable members 31 in an area where the influence of swelling of the superabsorbent polymer material is suppressed, further enhancing the upward lifting effect of the widthwise side region C12. Furthermore, this arrangement reduces the distance between the side elastic members 111 and the leg gather elastic members 18, allowing their respective elastic contractile forces to act synergistically on the widthwise side region C12. From the same perspective, it is more preferable to have a combination of the side elastic members 111 and the absorber elastic members 161. In order to more effectively apply the contractile force to the widthwise side regions C12, the side elastic members 111 are preferably arranged in an arc shape that is convex toward the waist opening 12, as shown in FIG.

[0063] 3, the number of stacked sheets in the widthwise side regions C12 is preferably greater than the number of stacked sheets in the widthwise central region C11. As a result, the widthwise side regions C12, which have a relatively greater number of stacked sheets, have higher rigidity than the widthwise central region C11, making them relatively less stretchable.

[0064] Furthermore, in the diaper 10, it is preferable that the crotch portion 10C is configured to be stretchable in the width direction X as well as the front-to-back direction Y. An example of a configuration that allows stretch in the width direction X is to use a member that is not oriented and is stretchable in all directions. This member that is stretchable in all directions may be the above-mentioned crotch stretchable member 31, or it may be a separate member used together with the crotch stretchable member 31. This allows stretching in both the front-to-back direction Y and the width direction X, improving the degree of freedom when the superabsorbent polymer material swells, and thereby improving liquid absorption efficiency.

[0065] With respect to the diaper 10, when the diaper 10 is viewed from the abdominal portion 10F side in a plan view in its natural state before being worn, it is preferable that the ratio (S2 / S1) of the length S2 between the ends in the width direction X of the absorbent 16 on the fold line CL at the lower end of the crotch portion 10C in the length direction T to the length S1 in the width direction X between the lower ends of the side seal portions 11, 11 be 0.3 to 0.7. This means that in the natural state before being worn, the width (length in the width direction X) of the crotch portion 10C is narrower than conventionally, resulting in a V-shaped outline (which in the present invention also includes a slightly curved outline). The "natural state" before wearing referred to here is as defined above. The "length S1 in the width direction X between the lower ends of the side seal portions 11, 11" is the length obtained by connecting the outermost left and right edges of the lower ends of the side seal portions 11, 11 in a straight line along the width direction X, as shown in Figs. 1 and 8. The "length S2 between the ends in the width direction X of the absorbent 16 on the bifold line CL at the lower end of the crotch portion 10C in the length direction T" is the length obtained by connecting the ends in the width direction X of the absorbent 16 (absorbent core 16A + core wrap sheet 16B) along the lower end of the crotch portion 10C in the length direction T in a straight line along the width direction X, as shown in Fig. 1. The lower end of the crotch portion 10C is the boundary between the front crotch portion CF and the back crotch portion CR folded back in the front-to-rear direction along the bifold line CL. At the lower end of the crotch portion 10C of the diaper 10 in its natural state as shown in FIG. 1, the length S2 between the ends of the absorbent body 16 on the folding line CL can be determined. The diaper 10 has the aforementioned length ratio (S2 / S1) in the width direction X, so that the crotch portion 10C has a V-shaped, underwear-like outline (silhouette) when viewed from the front in a natural state before being worn (see FIG. 8). Furthermore, by setting the ratio within this range, the width of the crotch portion relative to the overall width of the diaper is reduced, thereby eliminating bulkiness in the crotch portion and improving fit. On the other hand, the outline (silhouette) of a conventional pants-type diaper, as shown in FIG. 9, is bowl-shaped or cylindrical in shape from the bottom end of the side seal portion to the crotch portion, which is far from an underwear-like outline (silhouette). In contrast, the diaper 10 of the present embodiment has the aforementioned length ratio (S2 / S1) in the width direction X, so that the crotch portion 10 has a V-shaped outline resembling that of a typical underwear when viewed from the front in a natural state before being worn. Even if the diaper 10 has a narrow crotch portion 10C before wearing, the diaper 10 can achieve an underwear-like appearance and excellent liquid absorbency when absorbing excrement during wear by virtue of the aforementioned configuration that allows the crotch portion 10C to stretch in the front-to-back direction Y. In fact, by having the underwear-like appearance with the ratio (S2 / S1) before wearing, the V-shaped appearance during wear can be more clearly defined. From the above viewpoints, the ratio (S2 / S1) is preferably equal to or less than 0.70, more preferably equal to or less than 0.65, and even more preferably equal to or less than 0.60. From the viewpoint of ensuring the absorption capacity, the ratio (S2 / S1) is preferably 0.3 or more, more preferably 0.35 or more, and even more preferably 0.40 or more.

[0066] The components constituting the diaper 10 can be formed using various materials used in this type of article. For example, the hydrophilic fibers used in the absorbent core 16A can be fibers having a hydrophilic surface, such as cellulose fibers such as pulp, or synthetic fibers that have been hydrophilized with a surfactant or the like as needed.

[0067] Although particulate superabsorbent polymers are generally used, fibrous forms are also acceptable. When particulate superabsorbent polymers are used, they may be spherical, blocky, bale-shaped, or amorphous. Polymers or copolymers of acrylic acid or alkali metal acrylates are generally used as superabsorbent polymers. Examples include polyacrylic acid and its salts, and polymethacrylic acid and its salts. Sodium salts of polyacrylates and polymethacrylates are preferred. Copolymers of acrylic acid or methacrylic acid copolymerized with comonomers such as maleic acid, itaconic acid, acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, 2-(meth)acryloylethanesulfonic acid, 2-hydroxyethyl (meth)acrylate, or styrenesulfonic acid, within limits that do not impair the performance of the superabsorbent polymer, can also be used.

[0068] When the core wrap sheet 16B is made of a material other than the crotch stretchable member 31, examples include paper or pulp sheets made from hydrophilic fibers, and hydrophilic nonwoven fabrics.

[0069] The various elastic members mentioned above may be made of ordinary elastic materials used in wearable articles such as diapers and sanitary napkins. Examples of materials include synthetic rubbers such as styrene-butadiene, butadiene, isoprene, and neoprene, natural rubber, EVA, elastic polyolefins, and polyurethanes. The elastic members may be in the form of threads or strings (such as flat rubber) with cross sections that are rectangular, square, circular, or polygonal, or may be multifilament threads.

[0070] The exterior body 2 may be configured with one layer or two or more layers, and in either case, its constituent materials may include nonwoven fabric, a laminate of nonwoven fabric and resin film, porous film, etc. Furthermore, the exterior body 2 is preferably liquid-impermeable from the viewpoint of leak prevention, and is preferably breathable and vapor-permeable to prevent excessive humidity buildup inside the diaper. Furthermore, when the outer layer sheet 41 disposed in the crotch portion 10C is made of a material other than the crotch stretchable member 31, the same material as that of the exterior body 2 described above can be used.

[0071] The topsheet 14 constituting the absorbent body 1 is preferably a hydrophilic thermobonded nonwoven fabric, particularly an air-through nonwoven fabric, from the viewpoints of rapid absorption of excreted body fluids, transfer of the fluid to the absorbent body, and comfort of touch. The topsheet 14 is preferably made of hydrophilically treated thermoplastic resin fibers, and the fibers are preferably three-dimensionally crimped, such as secondary or tertiary crimped fibers. Specifically, polyethylene, polypropylene, polyester, nylon, or composite fibers thereof are prepared and coated with various hydrophilizing agents before being cut to a predetermined length to form staple fibers. Examples of hydrophilizing agents that can be used include various alkyl sulfonates, such as α-olefin sulfonates; acrylates; acrylate / acrylamide copolymers; ester amides; salts of ester amides; polyethylene glycol and its derivatives; water-soluble polyester resins; various silicone derivatives; various sugar derivatives; and mixtures thereof.

[0072] When the leak-barrier sheet 15 is made of a material other than the crotch stretchable members 31, there are no particular limitations on the material as long as it is liquid-resistant and moisture-permeable. Examples include porous films obtained by melt-kneading a hydrophobic thermoplastic resin with a minute inorganic filler such as calcium carbonate or an incompatible organic polymer to form a film, and then uniaxially or biaxially stretching the film. Examples of such thermoplastic resins include polyolefins. Examples of such polyolefins include high- to low-density polyethylene, linear low-density polyethylene, polypropylene, and polybutene, which can be used alone or in combination.

[0073] A water-repellent nonwoven fabric is preferable for the side sheet 17, and various water-repellent or water-repellent treated nonwoven fabrics can be used from among spunbond nonwoven fabrics, meltblown nonwoven fabrics, spunlace nonwoven fabrics, heat-rolled nonwoven fabrics, needle-punched nonwoven fabrics, etc. Particularly preferred are, for example, spunbond nonwoven fabrics, spunbond-meltblown (SM) nonwoven fabrics, spunbond-meltblown-spunbond (SMS), spunbond-meltblown-meltblown-spunbond (SMMS), spunbond-spunbond-meltblown-spunbond (SSMS) nonwoven fabrics, etc.

[0074] The pants-type absorbent article of the present invention is not limited to the embodiment of the diaper 10 described above, but is a concept that includes various articles having a pants-type structure. The pants-type absorbent article of the present invention may be for babies or adults, and may be in a form other than a diaper, such as sanitary shorts, shorts-type napkins, disposable shorts, etc.

[0075] In relation to the above-described embodiment, the present invention further discloses the following pants-type absorbent article. <1> A pants-type wearing article which is divided into a abdominal portion arranged on the abdominal side of a wearer, a crotch portion arranged on the crotch side, and a dorsal portion arranged on the dorsal side, and which has a body length direction and a width direction perpendicular to the body length direction, and which is provided with a pair of side seal portions where both side edges of the abdominal portion and the dorsal portion are joined together, an absorbent body including an absorbent core arranged along a front-to-rear direction connecting the crotch portion with the abdominal portion and the back portion; a crotch stretchable member configured to be stretchable in the front-to-rear direction and disposed closer to the skin side than the absorbent core in at least a region of the crotch portion that overlaps the absorbent core, a member in the crotch region that is closer to the skin than the absorbent core, including the crotch stretchable member, stretches to 1.1 to 1.5 times its natural state before wearing when subjected to a tensile load of 2 N / 50 mm along the front-to-rear direction; A pants-type absorbent article in which, when the absorbent core absorbs liquid, the crotch portion stretches at least in the front-to-back direction in accordance with the extension of the crotch stretch member, at a member on the non-skin-facing side of the absorbent core.

[0076] <2> the crotch portion includes a widthwise central region and widthwise side regions, and the widthwise central region has a greater longitudinal extensibility than the widthwise side regions; <1> The pants-type absorbent article according to claim 1. <3> The elongation rate of the widthwise central region is 1.1 times or more and 1.3 times or less than the elongation rate of the widthwise side regions. <2> The pants-type absorbent article according to claim 1. <4> The crotch stretchable members are arranged in a contracted state in the natural state. <1> ~ <3> The pants-type absorbent article according to any one of the above. <5> The crotch stretch member is a sheet-like member. <1> ~ <4> The pants-type absorbent article according to any one of the above. <6> The crotch stretchable member has a plurality of string-like or thread-like elastic members extending in the front-rear direction and arranged in the width direction. <1> ~ <5> The pants-type absorbent article according to any one of the above. <7> The crotch stretchable members are arranged to overlap a widthwise central region and widthwise side regions that divide the crotch portion in the width direction, The diameter of the string-like or thread-like elastic member disposed in the width direction side region is larger than the diameter of the string-like or thread-like elastic member disposed in the width direction central region. <6> The pants-type absorbent article according to claim 1. <8> The crotch stretchable members are arranged to overlap a widthwise central region and widthwise side regions that divide the crotch portion in the width direction, the pitch of the string-like or thread-like elastic members arranged in the width direction side regions is narrower than the pitch of the string-like or thread-like elastic members arranged in the width direction central region; <6> or <7> The pants-type absorbent article according to claim 1. <9> The widthwise length of the crotch stretchable member is the same as the widthwise length of the absorbent core on the fold line at the lower end of the crotch portion in the body length direction, or is longer than the widthwise length of the absorbent core and shorter than the widthwise length of the absorbent body. <1> ~ <8> The pants-type absorbent article according to any one of the above. <10> The length in the width direction of the crotch stretchable member is equal to or greater than the length in the width direction of the absorber on a folding line at the lower end of the crotch portion in the length direction. <1> ~ <8> The pants-type absorbent article according to any one of the above. <11> The length of the crotch stretchable member in the front-to-back direction is shorter than the length of the absorbent core in the front-to-back direction. <1> ~ <10> The pants-type absorbent article according to any one of the above. <12> The absorbent core is a mixed stack of superabsorbent polymer material and hydrophilic fiber, and the ratio of the mass content of the hydrophilic fiber to the mass content of the superabsorbent polymer material (former / latter) is more than 0 mass% and less than 100 mass%. <1> ~ <11> The pants-type absorbent article according to any one of the above. <13> The absorbent core is made of a superabsorbent polymer material. <1> ~ <11> The pants-type absorbent article according to any one of the above. <14> The superabsorbent polymer material has an absorption capacity of 15 g / g or more under a pressure of 2 kPa. <12> or <13> The pants-type absorbent article according to claim 1. <15> The basis weight of the superabsorbent polymer material in the crotch area is 100 g / m 2 The above <12> ~ <14> The pants-type absorbent article according to any one of the above. <16> The absorbent core does not include a groove portion extending in the front-rear direction at least in the crotch portion. <1> ~ <15> The pants-type absorbent article according to any one of the above. <17> The absorbent body has absorbent body elastic members joined and fixed in a stretched state along the front-rear direction on both sides of the absorbent core. <1> ~ <16> The pants-type absorbent article according to any one of the above. <18> The crotch stretchable member has side elastic members in both side regions that connect the front-rear direction ends of the crotch portion to the side seal portions. <1> ~ <17> The pants-type absorbent article according to any one of the above. <19> the number of stacked sheets in the width direction side regions is greater than the number of stacked sheets in the width direction central region; <2> ~ <18> The pants-type absorbent article according to any one of the above. <20> The crotch stretchable member is joined and fixed in a stretched state along the front-to-rear direction at the side of the crotch portion closest to the skin, and is contracted in the natural state. <1> ~ <19> The pants-type absorbent article according to any one of the above. <21> The crotch portion is configured to be stretchable in the width direction in addition to the front-to-rear direction. <1> ~ <20> The pants-type absorbent article according to any one of the above. <22> When the pants-type absorbent article in a natural state before being worn is viewed from the abdominal side in a plan view, the ratio (latter / former) of the length between the lower ends of the side seal portions in the width direction to the length between the ends of the absorbent body on a fold line at the lower end of the crotch portion in the body length direction is 0.3 or more and 0.7 or less. <1> ~ <21> The pants-type absorbent article according to any one of the above. [Explanation of symbols]

[0077] 1 absorbent body 16 Absorbent 16A absorbent core 16B Core Wrap Sheet 16C (Area within the absorbent body) where no absorbent core is located 2. Exterior body 31 Elastic member for crotch 41 Outer layer sheet 10F Abdominal part of diaper 10C Diaper crotch C1 Crotch main absorption area C2 crotch sub-absorbent area C11 Width center area C12 Width direction side area 10R Back side of diaper CL fold line T Diaper length direction X Diaper width direction Y: The front-to-back direction connecting the crotch part of the diaper with the abdominal and dorsal parts (the longitudinal direction when the diaper is unfolded)

Claims

1. A pants-type wearing article which is divided into a abdominal portion arranged on the abdominal side of a wearer, a crotch portion arranged on the crotch side, and a dorsal portion arranged on the dorsal side, and which has a body length direction and a width direction perpendicular to the body length direction, and which is provided with a pair of side seal portions where both side edges of the abdominal portion and the dorsal portion are joined together, an absorbent body including an absorbent core arranged along a front-to-rear direction connecting the crotch portion with the abdominal portion and the back portion; a crotch stretchable member configured to be stretchable in the front-to-rear direction and disposed closer to the skin side than the absorbent core in at least a region of the crotch portion that overlaps the absorbent core, a member in the crotch region that is closer to the skin than the absorbent core, including the crotch stretchable member, stretches to 1.1 to 1.5 times its natural state before wearing when subjected to a tensile load of 2 N / 50 mm along the front-to-rear direction; A pants-type absorbent article in which, when the absorbent core absorbs liquid, the crotch portion stretches at least in the front-to-back direction in accordance with the extension of the crotch stretch member, at a member on the non-skin-facing side of the absorbent core.

2. 2. The pants-type absorbent article according to claim 1, wherein the crotch portion includes a widthwise central region and widthwise side regions, and the elongation rate in the front-to-back direction of the widthwise central region is greater than the elongation rate in the front-to-back direction of the widthwise side regions.

3. The pants-type absorbent article according to claim 2, wherein the stretch rate of the widthwise central region is 1.1 to 1.3 times the stretch rate of the widthwise side regions.

4. The pants-type absorbent article according to any one of claims 1 to 3, wherein the crotch stretchable members are arranged in a contracted state in the natural state.

5. The pants-type absorbent article according to any one of claims 1 to 3, wherein the crotch stretchable member is a sheet-like member.

6. The pants-type absorbent article according to any one of claims 1 to 3, wherein the crotch stretchable members have a plurality of string-like or thread-like elastic members extending in the front-rear direction and arranged in the width direction.

7. The crotch stretchable members are arranged to overlap a widthwise central region and widthwise side regions that divide the crotch portion in the width direction, 7. The pants-type absorbent article according to claim 6, wherein the diameter of the string-like or thread-like elastic members arranged in the widthwise side regions is larger than the diameter of the string-like or thread-like elastic members arranged in the widthwise central region.

8. The crotch stretchable members are arranged to overlap a widthwise central region and widthwise side regions that divide the crotch portion in the width direction, 7. The pants-type absorbent article according to claim 6, wherein the pitch of the string-like or thread-like elastic members arranged in the widthwise side regions is narrower than the pitch of the string-like or thread-like elastic members arranged in the widthwise central region.

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