Underpants-type absorbent article

Abstract

This underpants-type absorbent article (1) has an absorbent body (10) provided with an absorbent core (11). The underpants-type absorbent article (1) has a crotch elastic region (ER) defined by a crotch elastic member (40) provided more on the non-skin side than the absorbent core (11), and has left-right direction elastic members (24-26). The underpants-type absorbent article does not have a portion where the crotch elastic region (ER) and the left-right direction elastic members (24-26) overlap in the longitudinal direction. In a region (IFR) overlapping the absorbent core (11) when viewed in the thickness direction and overlapping the crotch elastic region (ER) in the longitudinal direction, a sheet member (23) provided closest to the non-skin side has a non-present portion (75) in which an adhesive is not present, and the length of the non-present portion (75) in the longitudinal direction and the left-right direction is 1 / 2 or more of the length of the crotch elastic region (ER) in the longitudinal direction and the left-right direction.

Description

Pants-type absorbent article

[0001] The present invention relates to a pants-type absorbent article.

[0002]

[0003] Conventionally, in a pants-type absorbent article (e.g., pants-type diaper) including an absorbent main body and waistband members arranged to cover the front and rear of the absorbent main body from the non-skin side, a technique has been known in which an elastic member (crotch elastic member) that stretches along the longitudinal direction of the absorbent main body is provided to improve the fit of the absorbent main body in the crotch area. For example, Patent Document 1 discloses a technique related to a diaper (absorbent article) that includes leg elastics 7A that stretch along the width direction and a central elastic member 60 (corresponding to the crotch elastic member) that stretches along the longitudinal direction, and that prevents the absorbent main body 40 from moving away from the wearer's skin due to contraction of the central elastic member 60, thereby improving wearing comfort.

[0003] JP 2010-279612 A

[0004] In absorbent articles equipped with such crotch elastic members, wrinkles tend to form in the crotch area due to the contraction of the crotch elastic members. However, if wrinkles that should not normally be present in underwear form in the crotch area and are visible, the user (wearer) may be more likely to recognize the difference from underwear and experience discomfort. Furthermore, the wearer may be more likely to realize that they are wearing a diaper, not underwear, which may cause psychological stress.

[0005] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a pants-type absorbent article that has crotch elastic members and looks like underwear.

[0006] The main invention for achieving the above object is a pants-type absorbent article having an absorbent main body with an absorbent core, which has a longitudinal direction, a lateral direction, and a thickness direction that intersect with one another in a developed and stretched state, and which has a crotch elastic region that is defined by a crotch elastic member that is provided on the non-skin side of the absorbent core and stretches along the longitudinal direction, and has a lateral elastic member that is continuous from one end side to the other end side in the lateral direction, and which has no overlapping portion between the crotch elastic region and the lateral elastic member in the longitudinal direction, and which has a front when viewed in the thickness direction. In a region overlapping the absorbent core and overlapping with the crotch elastic region in the longitudinal direction, the sheet member closest to the skin among the sheet members provided on the farthest side from the skin side of the crotch elastic member has a non-present portion where no adhesive is present, and the length of the non-present portion in the longitudinal direction is at least half of the length of the crotch elastic region in the longitudinal direction, or the length of the non-present portion in the left-right direction is at least half of the length of the crotch elastic region in the left-right direction. Other features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0007] According to the present invention, it is possible to provide a pants-type absorbent article that has crotch elastic members and looks like underwear.

[0008] 1 is a front view of the pants-type disposable diaper 1 as viewed from the abdominal side. FIG. 4A is a plan view of the pants-type disposable diaper 1 in an unfolded and stretched state. FIG. 4B is a schematic cross-sectional view of the pants-type disposable diaper 1 taken along the line CC of FIG. 2. FIG. 4A is a plan view of the absorbent main body 10 as viewed from the skin side. FIG. 4B is a schematic cross-sectional view of the absorbent main body 10 at the longitudinal centerline CL. FIG. 5A and FIG. 5B are diagrams illustrating the joining of the absorbent main body 10 and the waistline member 20 (outer layer member 20). FIG. 6A and FIG. 6B are diagrams illustrating the relationship between the main body joint 70 and wrinkles formed in the crotch portion of the diaper 1. FIG. 6B is a diagram illustrating the relationship between the main body joint 70 and wrinkles formed in the crotch portion of the diaper 1. FIG. 5B is an enlarged cross-sectional view of FIG. 5B. FIG. 5B is a plan view and a cross-sectional view of a modified diaper 1 in an unfolded and stretched state. FIG. 6C is a three-view diagram illustrating the configuration of a diaper 2 of a second embodiment. FIG. 6D is a three-view diagram illustrating the configuration of a diaper 3 of a third embodiment.

[0009] At least the following matters will become clear from the description of this specification and the accompanying drawings. (Aspect 1) a pant-type absorbent article having an absorbent main body with an absorbent core, in an unfolded and stretched state, having longitudinal, left-right, and thickness directions that intersect with one another, and having a crotch elastic region partitioned by a crotch elastic member that is located closer to the skin than the absorbent core and stretches along the longitudinal direction, and having left-right elastic members that are continuous from one end side to the other end side in the left-right direction, and having no portion where the crotch elastic region and the left-right elastic member overlap in the longitudinal direction, and having a non-existent portion that overlaps with the absorbent core when viewed in the thickness direction and in the region overlapping with the crotch elastic region in the longitudinal direction, where the adhesive is not present in the sheet member that is located nearest to the skin among the sheet members that are located closer to the skin than the crotch elastic member, and the length of the non-existent portion in the longitudinal direction is at least half of the length of the crotch elastic region in the longitudinal direction, or the length of the non-existent portion in the left-right direction is at least half of the length of the crotch elastic region in the left-right direction.

[0010] According to the pants-type absorbent article of Aspect 1, the crotch elastic region does not intersect with the left-right elastic members, and a stretching force along the longitudinal direction is firmly applied to the absorbent core, thereby improving the fit of the crotch area. Furthermore, in the crotch fit region of the absorbent core, which is susceptible to the influence of contraction of the crotch elastic region, there is a certain amount of area (non-existing area) where the sheet member closest to the skin among the sheet members provided on the non-skin side of the crotch elastic member is not joined to the adjacent sheet member on that side. Therefore, when the crotch elastic region contracts, the influence of the contraction is less likely to be transmitted to the sheet member closest to the skin in the non-existing area, and wrinkles are less likely to form on the non-skin side. This makes it possible to realize a pants-type absorbent article in which wrinkles are less noticeable in the crotch area and which looks more like underwear.

[0011] (Aspect 2) The pants-type absorbent article according to Aspect 1, wherein, when viewed in the thickness direction, a central adhesive-presenting portion is provided in which adhesive is provided in the sheet member provided furthest from the skin in a portion overlapping with the crotch elastic region.

[0012] According to the pants-type absorbent article of aspect 2, at least in the portion overlapping with the crotch elastic region, wrinkles formed in the absorbent core due to the stretchability of the crotch elastic region are easily transmitted to the waistband member on the non-skin side (the sheet member provided furthest from the skin side), and the wrinkles become visible on the surface of the waistband member, making it easier for the user to recognize that the article has a good fit in the crotch area.

[0013] (Aspect 3) The pants-type absorbent article according to aspect 1 or 2, wherein the sheet member provided closest to the skin has the central adhesive-presenting portion over an entire portion that overlaps with the crotch elastic region in the left-right direction.

[0014] According to the pants-type absorbent article of Aspect 3, when the absorbent core shrinks in the longitudinal direction due to the stretchability of the crotch elastic region and wrinkles are formed, the wrinkles are transmitted to the waistband member (the sheet member provided closest to the skin) across the entire left-right area of ​​the crotch elastic region, which makes the wrinkles formed in the region of the crotch part that overlaps with the crotch elastic region more visible, making it easier to impress upon the user a good fit.

[0015] (Aspect 4) The pants-type absorbent article according to any one of Aspects 1 to 3, wherein the sheet member provided closest to the skin has the central adhesive-present portion over an entire portion that overlaps with the crotch elastic region in the longitudinal direction.

[0016] According to the pants-type absorbent article of Aspect 4, when wrinkles are formed due to longitudinal contraction of the absorbent core due to the stretchability of the crotch elastic region, the wrinkles are transmitted to the waistband member (the sheet member provided closest to the skin) over the entire longitudinal area of ​​the crotch elastic region, making wrinkles formed in the region of the crotch part that overlaps with the crotch elastic region more visible, thereby giving the user the impression of a good fit.

[0017] (Aspect 5) The pants-type absorbent article according to any one of Aspects 1 to 4, wherein the sheet member provided closest to the skin has the adhesive-free portions adjacent to both outer sides of the central adhesive-present portion in the left-right direction.

[0018] According to the pants-type absorbent article of Aspect 5, when the crotch elastic regions contract, wrinkles are formed in the portion of the waistband member that is joined to the absorbent main body at the central adhesive portion, whereas wrinkles are less likely to form in the portions (non-adhesive portions) on both sides of the central adhesive portion that are not joined to the absorbent main body. Therefore, it is possible to make wrinkles less noticeable overall while still providing a good fit in the crotch area.

[0019] (Aspect 6) The pants-type absorbent article according to any one of Aspects 1 to 5, further outward in the left-right direction from the non-adhesive portions adjacent to both outer sides of the central adhesive-present portion, the sheet member provided closest to the skin having adhesive thereon.

[0020] According to the pants-type absorbent article of Aspect 6, by providing adhesive-presented portions on both the left and right sides of the non-present portion, it is possible to prevent a part of the waistband member (the inner layer sheet) from rolling up or becoming bunched up at both left and right ends of the absorbent main body, thereby improving the fit of the pants-type absorbent article in the crotch area, particularly in the leg openings, and making the article look like underwear when worn.

[0021] (Aspect 7) The pants-type absorbent article according to any one of Aspects 1 to 6, wherein the adhesive-free portions are not present on either side of the central adhesive-present portion in the longitudinal direction.

[0022] According to the pants-type absorbent article of aspect 7, by firmly joining the absorbent body and the waistband member in the region outside (front and back) the crotch elastic region in the longitudinal direction, the outermost layer of the waistband member is prevented from floating up against the skin when worn, making it easier for the appearance of the pants-type absorbent article to look like underwear.

[0023] (Aspect 8) The pants-type absorbent article according to any one of Aspects 1 to 7, wherein the sheet member disposed adjacent to the skin side of the crotch elastic member and the sheet member disposed furthest from the skin side have a portion that is not joined in the thickness direction.

[0024] According to the pants-type absorbent article of Aspect 8, when the crotch elastic regions contract along the longitudinal direction, wrinkles are also likely to form in the skin-side sheet member. However, since the skin-side sheet member and the sheet member provided on the non-skin-side have portions (non-existing portions) where they are not joined to each other in the thickness direction, wrinkles formed in the skin-side sheet member are prevented from being transmitted to the sheet member on the non-skin-side. This makes it difficult for wrinkles to form in the waistband member, allowing the appearance of the pants-type absorbent article to look like underwear when worn.

[0025] (Aspect 9) The pants-type absorbent article according to any one of Aspects 1 to 8, wherein the absorbent core has a waisted portion in the longitudinal center that is narrower in the left-right direction than both longitudinal end portions, and the position of the waisted portion where the width in the left-right direction is narrowest in the longitudinal direction overlaps with the crotch elastic region.

[0026] According to the pants-type absorbent article of aspect 9, the width of the absorbent core (waisted portion) is narrowest in the crotch portion of the absorbent core where wrinkles are likely to form, and therefore wrinkles are less likely to become excessively large and less noticeable compared to when wrinkles are formed in a wider region of the absorbent core. Therefore, the appearance of the pants-type absorbent article when worn can be made to look more like underwear.

[0027] (Aspect 10) The pants-type absorbent article according to any one of Aspects 1 to 9, wherein the average basis weight of the first sheet member provided on the non-skin side of the crotch elastic member in the thickness direction is different from the average basis weight of the second sheet member provided on the non-skin side of the first sheet member.

[0028] According to the pants-type absorbent article of Aspect 10, by laminating the first sheet member and the second sheet member having different basis weights in the thickness direction, it is possible to easily prevent wrinkles formed in the first sheet member from being directly transmitted to the second sheet member, thereby making wrinkles less noticeable in the crotch area and making the appearance more similar to underwear.

[0029] (Aspect 11) The pants-type absorbent article according to any one of aspects 1 to 10, wherein the average basis weight of the second sheet member is greater than the average basis weight of the first sheet member.

[0030] According to the pants-type absorbent article of Aspect 11, since a sheet member with a larger basis weight tends to be more rigid than a sheet member with a smaller basis weight, by disposing the second sheet member with a larger basis weight on the non-skin side, it is possible to easily prevent large wrinkles from forming on the non-skin side, which makes wrinkles less noticeable in the crotch area and makes the article appear more like underwear.

[0031] (Aspect 12) The pants-type absorbent article according to any one of aspects 1 to 11, wherein the average fiber width of the fibers constituting the first sheet member is different from the average fiber width of the fibers constituting the second sheet member.

[0032] According to the pants-type absorbent article of Aspect 12, a sheet member having a larger average fiber width is less likely to bend and less likely to form creases, which makes it easier to prevent wrinkles formed in the first sheet member on the skin side from propagating directly to the second sheet member on the non-skin side, making wrinkles less noticeable in the crotch area and making the article appear more like underwear.

[0033] (Aspect 13) The pants-type absorbent article according to any one of Aspects 1 to 12, wherein the fiber orientation direction of the first sheet member and the fiber orientation direction of the second sheet member intersect with each other.

[0034] In the pants-type absorbent article of Aspect 13, the stretchability of the first sheet member along the longitudinal direction is likely to be different from the stretchability of the second sheet member along the longitudinal direction, and the likelihood of wrinkles forming when the crotch elastic region contracts along the longitudinal direction is also likely to be different. Therefore, even if wrinkles form in the first sheet member, the likelihood of the formed wrinkles being transferred directly to the second sheet member can be reduced. This makes the wrinkles less noticeable in the crotch area, making the article more likely to look like underwear.

[0035] (Aspect 14) The pants-type absorbent article of any one of Aspects 1 to 13, wherein a plurality of the crotch elastic members are provided at intervals in the left-right direction, the plurality of crotch elastic members including a first crotch elastic member and a second crotch elastic member arranged adjacent to the outer side of the first crotch elastic member in the left-right direction, and wherein a force required to stretch the first crotch elastic member by a unit length in the longitudinal direction is greater than a force required to stretch the second crotch elastic member by a unit length in the longitudinal direction.

[0036] According to the pants-type absorbent article of Aspect 14, the stretching force of the crotch elastic region is weaker toward the outside in the left-right direction, so that when the crotch elastic region contracts in the longitudinal direction, the wrinkles formed are smaller toward the outside in the left-right direction, which makes the wrinkles in the crotch area less noticeable and makes the article look more like underwear.

[0037] (Aspect 15) The pants-type absorbent article according to any one of Aspects 1 to 14, wherein the sheet member disposed closest to the skin side of the absorbent main body is discontinuous between a central portion and both side portions in the left-right direction.

[0038] According to the pants-type absorbent article of Aspect 15, even if wrinkles are formed in the sheet member (elastic member cover sheet) in the center portion in the left-right direction due to contraction of the crotch elastic region, the influence of the wrinkles is unlikely to be transmitted from the sheet member in the center portion to the sheet members (side sheets) on both sides. In other words, wrinkles are unlikely to be formed in the sheet members (side sheets) on both sides. This makes it difficult for the range of wrinkles formed in the waistband member to spread in the left-right direction, making the wrinkles in the crotch region less noticeable. Therefore, the appearance of the pants-type absorbent article can be made to look more like underwear.

[0039] (Aspect 16) The pants-type absorbent article according to any one of Aspects 1 to 15, wherein, of the sheet members arranged on the farthest side of the absorbent main body, the sheet member overlapping with the crotch elastic member in the central portion in the left-right direction has portions at both ends in the left-right direction where no adhesive is provided.

[0040] According to the pants-type absorbent article of Aspect 16, even if wrinkles are formed in the sheet member (elastic member cover sheet) in the left-right center due to contraction of the crotch elastic region, the dry edges (areas where no adhesive is provided) on both left and right sides prevent the influence of the wrinkles from being transmitted outward in the left-right direction. This makes it more difficult for the range of wrinkles formed in the waistband member to spread in the left-right direction, making the wrinkles less noticeable in the crotch region. This makes it easier for the appearance of the pants-type absorbent article to look like underwear.

[0041] First Embodiment Hereinafter, a pants-type absorbent article according to the present invention will be described taking a pants-type disposable diaper 1 (hereinafter also referred to as "diaper 1") as an example. However, the pants-type absorbent article according to the present invention is not limited to the above and can also be used as a sanitary napkin, sanitary shorts, etc.

[0042] <Basic structure of pants-type disposable diaper 1> Fig. 1 is a front view of the pants-type disposable diaper 1 as seen from the ventral side. Fig. 2 is a plan view of the pants-type disposable diaper 1 in an unfolded and stretched state. Fig. 3 is a schematic cross-sectional view of the pants-type disposable diaper 1 taken along the line CC in Fig. 2.

[0043] The unfolded state of the pants-type disposable diaper 1 (diaper 1) refers to the state in which the diaper 1 is opened and unfolded in a flat plane by separating a pair of side seam regions 5 provided on both sides of the diaper 1. The stretched state of the diaper 1 refers to the state in which the diaper 1 is stretched to the extent that wrinkles in the diaper 1 are no longer visible. Specifically, this refers to the state in which the diaper 1 is stretched until the dimensions of each component constituting the diaper 1 (e.g., the top sheet 12 and the inner layer sheet 23, which will be described later) match or are close to the dimensions of the component alone.

[0044] As shown in Fig. 1, the diaper 1 has a vertical direction, a horizontal direction, and a front-to-rear direction (directions passing through the paper in Fig. 1) that are perpendicular to one another, and has a waist opening BH and a pair of leg openings LH. The upper side in the vertical direction corresponds to the waist opening BH side, and the lower side corresponds to the crotch side. The front side in the front-to-rear direction corresponds to the wearer's abdomen, and the rear side corresponds to the wearer's back.

[0045] In the unfolded state shown in Fig. 2, the diaper 1 has a longitudinal direction, a left-right direction, and a thickness direction (a direction passing through the paper in Fig. 2) that intersect with one another. The left-right direction in the unfolded state of Fig. 2 is the same as the left-right direction in the pants-type state of Fig. 1. The longitudinal direction in the unfolded state is a direction along the up-down direction in the pants-type state. One side in the longitudinal direction corresponds to the front side (ventral side), and the other side corresponds to the rear side (dorsal side). As shown in Fig. 3, the thickness direction is the direction in which the materials constituting the diaper 1 are layered. In the thickness direction, the side that comes into contact with the wearer's skin is referred to as the skin side, and the opposite side is referred to as the non-skin side.

[0046] The diaper 1 comprises an absorbent main body 10 and an outer cover member 20 provided on the side away from the wearer's skin than the absorbent main body 10. As will be described in detail later, the absorbent main body 10 and the outer cover member 20 are bonded in the thickness direction using an adhesive such as a hot melt adhesive. Cover sheets 31, 32 may also be provided to cover both longitudinal ends of the absorbent main body 10 from the skin side (see FIG. 3). This prevents the edges of the absorbent main body 10 from digging into the wearer's skin and prevents the absorbent main body 10 from opening open.

[0047] The outer layer member 20 is a portion that is positioned around the waist of the wearer when the diaper 1 is worn, and hereinafter the outer layer member 20 is also referred to as the "waist member 20." As shown in Fig. 2 , when the diaper 1 is in an unfolded and stretched state, the portion of the waist member 20 that is forward (toward the ventral side) of a longitudinal center position CL of the diaper 1 is also referred to as the "front waist portion 20f," and the portion that is rearward (toward the back side) of the longitudinal center position CL of the diaper 1 is also referred to as the "rear waist portion 20b." When the diaper 1 is folded in half at the longitudinal center position CL from the unfolded state shown in Fig. 2 , the front waist portion 20f and the rear waist portion 20b, which are opposed in the thickness direction (front-rear direction), are joined at their left and right sides by a pair of side joining portions 5, thereby forming the pants-type diaper 1 as shown in Fig. 1 . Examples of joining methods using the side joining portions 5 include heat welding, ultrasonic welding, and joining methods using adhesives.

[0048] (Absorbent main body 10) Fig. 4A is a plan view of the absorbent main body 10 as seen from the skin side. Fig. 4B is a schematic cross-sectional view of the absorbent main body 10 at a central position CL in the longitudinal direction. The absorbent main body 10 includes an absorbent core 11 that absorbs and retains excretory liquids such as urine, a liquid-permeable top sheet 12 (e.g., a nonwoven fabric) arranged closer to the skin than the absorbent core 11, a liquid-impermeable back sheet 13 (e.g., a resin film such as polyethylene or polypropylene) arranged closer to the skin than the absorbent core 11, a liquid-permeable intermediate sheet 15 (e.g., a nonwoven fabric) arranged between the top sheet 12 and the absorbent core 11, a pair of side sheets 16, and an elastic member cover sheet 17.

[0049] The absorbent core 11 absorbs and retains excreted liquids such as urine. The surface of the absorbent core 11 may be covered with a liquid-permeable core wrap sheet 18 (e.g., tissue paper). The absorbent core 11 is made of a liquid-absorbent material, such as a water-retentive fiber or a superabsorbent polymer (so-called SAP), molded into a predetermined shape. In this embodiment, as shown in FIG. 4A , the absorbent core 11 has a generally hourglass shape with its longitudinal center narrowed inward in the left-right direction. However, the planar shape of the absorbent core 11 is not particularly limited, and may be, for example, rectangular in plan view. In this embodiment, the width (maximum width) of the absorbent main body 10 in the left-right direction is approximately equal to the width (maximum width) of the absorbent core 11 in the left-right direction.

[0050] A pair of leakage preventing walls 60 are provided along the longitudinal direction on both lateral sides of the absorbent body 10. As shown in Fig. 4B, portions of the side sheets 16 extending from both lateral sides of the non-skin side of the back sheet 13 are folded at multiple locations to form leakage preventing walls 60 on both lateral sides of the skin side of the top sheet 12. Leak preventing wall elastic members 61 (e.g., rubber threads) are attached to the leakage preventing walls 60 in a stretched state along the longitudinal direction. When the diaper 1 is worn, the stretchability of the leakage preventing wall elastic members 61 causes the leakage preventing walls 60 to stand up against the wearer's skin, thereby blocking body waste.

[0051] The absorbent body 10 also has a longitudinally stretchable crotch elastic member 40 in the left-right center and on the non-skin side in the thickness direction of the absorbent core 11. Specifically, the crotch elastic member 40 of this embodiment is attached in a stretched state along the longitudinal direction between the back sheet 13 provided on the non-skin side of the absorbent core 11 in the thickness direction and the elastic member cover sheet 17 arranged on the non-skin side of the back sheet 13. However, it is sufficient that the crotch elastic member 40 is provided on the non-skin side of the absorbent core 11, and for example, it may be provided between the core wrap sheet 18 (absorbent core 11) and the back sheet 13 on the non-skin side of the absorbent core 11.

[0052] In Fig. 4A, five crotch elastic members 41-45 are arranged longitudinally at intervals in the left-right direction in the center of the absorbent main body 10 (absorbent core 11). Hereinafter, the area defined by these five crotch elastic members 40 (41-45) will also be referred to as the "crotch elastic region ER." In other words, as shown by the diagonally slanted area slanting upward to the right in Fig. 4A, the area surrounded by the crotch elastic member 41 arranged on the most one side in the left-right direction and the crotch elastic member 45 arranged on the most other side is the crotch elastic region ER. However, the number and arrangement of the crotch elastic members 40 are not limited to this.

[0053] When the diaper 1 is worn, the elasticity of the crotch elastic member 40 (crotch elastic region ER) causes the central region of the absorbent core 11 in the left-right direction to deform three-dimensionally so that it becomes convex toward the skin, fitting to the crotch area and excretory opening, thereby achieving good absorbency and fit.

[0054] Furthermore, when the absorbent body 10 is viewed in the thickness direction, the region that overlaps with the absorbent core 11 and also overlaps with the crotch elastic region ER in the longitudinal direction is referred to as the "crotch fit region IFR." In Fig. 4A, the region indicated by diagonal lines slanting downward to the right, surrounded by the positions of the front and rear longitudinal ends of the crotch elastic region ER and the outlines (peripheries) of both the left and right sides of the absorbent core 11, is the crotch fit region IFR.

[0055] (Waistline member 20) The waistline member 20 (outer member 20) is a sheet member having a shape in which the longitudinal center portion is constricted inward in the left-right direction. As shown in Figures 2 and 3 , the waistline member 20 has a ventral outer layer sheet 21, a dorsal outer layer sheet 22, an inner layer sheet 23, waistline elastic members 24, 25, and a buttocks elastic member 26.

[0056] The ventral outer layer sheet 21, the back outer layer sheet 22, and the inner layer sheet 23 can be exemplified by flexible sheet members such as nonwoven fabrics. The inner layer sheet 23 forms the outer shape of the waistband member 20 and is a continuous sheet member extending longitudinally from the front (ventral side) to the back (dorsal side). The ventral outer layer sheet 21 is disposed closer to the skin than the inner layer sheet 23 and in a portion of the front waistband portion 20f. The ventral outer layer sheet 21 overlaps the side joint portion 5 in the longitudinal direction and has the same longitudinal length as the side joint portion 5 (see FIG. 2). The back outer layer sheet 22 is disposed closer to the skin than the inner layer sheet 23 and in a portion of the rear waistband portion 20b. The back outer layer sheet 22 overlaps the side joint portion 5 in the longitudinal direction and extends partially beyond the side joint portion 5 toward the crotch. In the flattened state of the diaper 1, the ventral outer sheet 21 and the dorsal outer sheet 22 are spaced apart in the longitudinal direction, with the inner sheet 23 exposed to the outside as the non-skin side of the diaper 1 therebetween.

[0057] The waist elastic members 24, 25 and the buttocks elastic members 26 are elastic members that stretch in the left-right direction, and examples thereof include rubber thread. As shown in FIG. 2 , the waist elastic members 24, 25 overlap the side joints 5 in the longitudinal direction. Hereinafter, the waist elastic members located in the front waistline portion 20f may also be referred to as the ventral waistline elastic members 24, and the waist elastic members 25 located in the rear waistline portion 20b may also be referred to as the back waistline elastic members 25. The buttocks elastic members 26 are located on the crotch side of the side joints 5 in the longitudinal direction (downward in the vertical direction). In this embodiment, there are two buttocks elastic members 26, but this number is not particularly limited.

[0058] 2, the buttocks elastic members 26 are cut in the center in the left-right direction and are arranged so as not to overlap with the absorbent core 11. This prevents the absorbent core 11 from contracting in the left-right direction due to the stretchability of the buttocks elastic members 26. Therefore, when the diaper 1 is worn, the absorbent core 11 can be brought into contact with the wearer's buttocks over a wide area, making it easier to achieve good fit and absorbency. However, the buttocks elastic members 26 do not necessarily have to be cut in the center, and may be provided continuously from one end to the other end in the left-right direction.

[0059] The waist elastic members 24, 25 and buttocks elastic members 26 are arranged side by side in the vertical direction and are attached in a stretched state in the left-right direction between the inner layer sheet 23 and the ventral outer layer sheet 21 or the back outer layer sheet 22. The left-right stretchability of these elastic members 24, 25, 26 allows the waist member 20 to fit the waist and buttocks of the wearer. In the diaper 1, the waist elastic members 24, 25 (and the buttocks elastic member 26 may also be included) are provided continuously from one left-right end to the other, and hereinafter these elastic members 24, 25 (26) are collectively referred to as "left-right elastic members."

[0060] <Appearance of Diaper 1> As described above, the diaper 1 of this embodiment improves the fit around the crotch area of ​​the wearer by providing the crotch elastic member 40 (crotch elastic region ER) in the left-right central portion of the absorbent main body 10. That is, when the stretching force of the crotch elastic member 40 (crotch elastic region ER) in the longitudinal direction acts on the absorbent core 11, the left-right central portion of the absorbent core 11 is lifted toward the skin and deformed into a convex shape, which is pushed up against the wearer's crotch area (excretory opening such as the vagina) and improves the fit.

[0061] In particular, in the diaper 1, the crotch elastic region ER (crotch elastic member 40) and the left-right elastic members (the waist elastic members 24, 25 and the buttocks elastic member 26) do not overlap with each other. This means that the longitudinal stretching force of the crotch elastic region ER and the lateral stretching force of the lateral elastic members are unlikely to interfere with each other, making it easier for the longitudinal stretching force of the crotch elastic region ER to act in the crotch fit region IFR. This improves the fit of the absorbent core 11 in the crotch area.

[0062] On the other hand, when the absorbent core 11 contracts in the longitudinal direction due to the elasticity of the crotch elastic region ER (crotch elastic member 40), wrinkles are likely to form in the lateral direction in the contracted portion. Since such wrinkles are unlikely to form when wearing normal underwear, a user (wearer) who visually observes a diaper 1 with wrinkles formed in the crotch region (crotch fit region IFR) will easily recognize the difference from underwear. Furthermore, this makes the wearer more aware that they are wearing a diaper and not underwear, which may cause psychological stress to the wearer.

[0063] Therefore, the diaper 1 ensures a good fit due to the elasticity of the crotch elastic region ER, while reducing the visibility of wrinkles formed in the crotch area, thereby giving the diaper 1 an underwear-like appearance when worn. Specifically, by adjusting the joint (main body joint 70, described below) between the absorbent main body 10 and the waistband member 20, which are layered in the thickness direction, wrinkles formed in the absorbent main body 10 (absorbent core 11) are less likely to be transmitted to the waistband member 20 on the non-skin side. This makes wrinkles less noticeable when the diaper 1 is viewed from the non-skin side. The structure for reducing the visibility of wrinkles in the crotch area of ​​the diaper 1 will be described in detail below.

[0064] 5A and 5B are diagrams illustrating the joining of the absorbent main body 10 and the waistline member 20 (outer layer member 20). Fig. 5A is a plan view of the absorbent main body 10 and the waistline member 20 in an unfolded and stretched state, and Fig. 5B is a schematic cross-sectional view taken along the A1-A1 arrows in Fig. 5A.

[0065] The absorbent main body 10 and the waistline member 20 are joined together by a main body joint 70 formed with an adhesive such as a hot melt adhesive. The main body joint 70 is formed by applying adhesive to the non-skin side of the absorbent main body 10 or the skin side of the waistline member 20 in the region indicated by the diagonally shaded area sloping downward to the right in Fig. 5A. Examples of adhesive application patterns include a so-called Ω pattern and a spiral pattern.

[0066] As shown in Fig. 5A , the main body joint 70 is provided over almost the entire area of ​​the absorbent main body 10 (absorbent core 11). Meanwhile, blank areas where no adhesive is provided are formed in the area inside the outline of the main body joint 70 shown by the hatched area in Fig. 5A and on both sides of the crotch elastic region ER in the left-right direction. These adhesive-free areas are referred to as non-present areas 75. In other words, the diaper 1 has areas (non-present areas 75) where the absorbent main body 10 and the waistline member 20 are not joined to each other.

[0067] 5B , of the sheet members (elastic member cover sheet 17 and inner layer sheet 23) provided closer to the skin than the crotch elastic member 40 (crotch elastic region ER), the sheet member provided closest to the skin (inner layer sheet 23) has a non-existent portion 75. That is, in the diaper 1, the inner layer sheet 23, which constitutes the layer closest to the skin of the waistband member 20, and the absorbent main body 10 provided adjacent to the inner layer sheet 23 on the skin side are not joined to each other at the non-existent portion 75.

[0068] When the diaper 1 having such a configuration is worn, if the absorbent core 11 shrinks in the longitudinal direction due to the stretchability (contractibility) of the crotch elastic region ER, the effect of the shrinkage is also transmitted to the waistline member 20 (inner layer sheet 23) joined to the non-skin side via the main body joining portion 70. On the other hand, in the non-existent portion 75, the effect of the shrinkage of the absorbent core 11 is not easily transmitted to the waistline member 20 (inner layer sheet 23). Therefore, wrinkles are less likely to form in the portion of the inner layer sheet 23 arranged on the non-skin side of the crotch elastic region ER that overlaps with the non-existent portion 75.

[0069] 6A and 6B are diagrams illustrating the relationship between the main body joint 70 and wrinkles formed in the crotch region of the diaper 1. First, Fig. 6A illustrates a comparative example in which the non-existent portion 75 is not formed. That is, Fig. 6A illustrates a case in which the main body joint 70 is formed (adhesive is provided) over the entire crotch fit region IFR (see the lower diagram in Fig. 6A ). In Fig. 6A , when the absorbent core 11 contracts in the longitudinal direction due to the stretchability of the crotch elastic region ER, multiple wrinkles are formed in the crotch fit region IFR of the absorbent core 11. Furthermore, the contraction of the crotch elastic region ER is transmitted to the inner layer sheet 23 (waist member 20) to which the main body joint 70 is joined, and therefore multiple wrinkles are also formed in the region of the inner layer sheet 23 (waist member 20) that overlaps with the crotch fit region IFR. As a result, as shown in the upper diagram of Figure 6A, multiple large wrinkles become easily visible in the crotch area (crotch fit region IFR) of the diaper 1, making the wearer more likely to notice the difference from underwear and feel uncomfortable.

[0070] In contrast, Figure 6B illustrates a case where the non-existent portion 75 described in Figure 5 is formed. That is, this illustrates a case where no adhesive is provided in at least a portion of the crotch fit region IFR (both sides of the crotch elastic region ER in the left-right direction). In the case of Figure 6B, when the absorbent core 11 contracts in the longitudinal direction due to the stretchability of the crotch elastic region ER, multiple wrinkles are formed in the crotch fit region IFR of the absorbent core 11, as in Figure 6A. The effects of contraction of the crotch elastic region ER are transmitted to the inner layer sheet 23 (waist member 20) to which it is joined via the main body joining portion 70, whereas the effects of this contraction are less likely to be transmitted to the inner layer sheet 23 (waist member 20) in the non-existent portion 75. That is, wrinkles are less likely to form in the region of the waist member 20 that overlaps with the non-existent portion 75. As a result, as shown in Fig. 6B, the wrinkles in the crotch portion (crotch fitting region IFR) of the diaper 1 on both sides of the crotch elastic region ER (absent regions 75) are smaller in size and number than in Fig. 6A, making the wrinkles less noticeable in the crotch portion, which makes the appearance of the diaper 1 when worn closer to underwear and less likely to cause discomfort to the wearer.

[0071] If the size of the non-existent portion 75 is small relative to the crotch elastic region ER, the effects of contraction of the crotch elastic region ER are likely to be transmitted to the inner layer sheet 23 (waist member 20) on the non-skin side, which may result in large wrinkles in the waist member 20. Therefore, in this embodiment, the non-existent portion 75 is set to a certain size or larger to prevent the effects of contraction of the crotch elastic region ER from being excessively transmitted to the inner layer sheet 23 (waist member 20). Specifically, the non-existent portion 75 is set so that its longitudinal length is at least half the longitudinal length of the crotch elastic region ER, or its lateral length is at least half the lateral length of the crotch elastic region ER. In FIG. 5 , the non-existent portion 75 is provided such that both the longitudinal and lateral lengths of the crotch elastic region ER are greater than half.

[0072] Thus, in the diaper 1, the crotch elastic region ER does not intersect with the lateral elastic members (24, 25, 26), allowing the absorbent core 11 to exert a strong longitudinal stretching force, thereby improving the fit of the crotch region. Furthermore, the crotch fit region IFR of the absorbent core 11, which is susceptible to the effects of contraction of the crotch elastic region ER, has a relatively large portion (non-existing portion 75) where the sheet member closest to the skin (the inner layer sheet 23) is not joined to the adjacent sheet member on the skin side of the crotch elastic member. Therefore, when the crotch elastic region ER contracts, the non-existing portion 75 is less likely to transmit the effects of the contraction of the crotch elastic region ER to the inner layer sheet 23 on the skin side, thereby reducing the likelihood of wrinkles forming on the non-skin side of the waistband member 20. This reduces the noticeable wrinkles in the crotch region, resulting in a diaper 1 that looks more like underwear.

[0073] It is also possible to form the non-existent portion 75 over a wider area. For example, by ensuring that the absorbent main body 10 and the waist member 20 (inner layer sheet 23) are not joined to each other over the entire area overlapping with the crotch fit region IFR when viewed in the thickness direction, it is possible to make wrinkles in the waist member 20 less noticeable. Figure 7 is a diagram illustrating the relationship between the main body joining portion 70 and wrinkles formed in the crotch part of the diaper 1, and shows, as a second comparative example, a case in which the non-existent portion 75 is formed over the entire crotch fit region IFR.

[0074] In the case of Figure 7, when the absorbent core 11 contracts in the longitudinal direction due to the stretchability of the crotch elastic region ER, multiple wrinkles are formed in the crotch fit region IFR of the absorbent core 11, as described in Figure 6A. Meanwhile, no adhesive is provided in the crotch fit region IFR (non-adhesive portion 75), and the absorbent main body 10 and waist member 20 are not joined to each other throughout the entire crotch fit region IFR. Therefore, wrinkles formed in the absorbent core 11 are not transmitted to the non-skin side of the crotch fit region IFR, and wrinkles are less likely to form on the non-skin side of the waist member 20. In other words, wrinkles are less visible even in the region overlapping with the crotch elastic region ER. If no wrinkles are visible in the crotch area (crotch fit region IFR), the user (wearer) may become concerned about the fit of the crotch area or the possibility of leakage.

[0075] In contrast, in the diaper 1 of this embodiment, adhesive is applied to the sheet member (inner layer sheet 23) closest to the skin in the portion overlapping the crotch elastic region ER when viewed in the thickness direction. That is, the waistline member 20 (inner layer sheet 23) and the absorbent main body 10 are joined to each other at the main body joining portion 70 on the non-skin side of the crotch elastic region ER. Therefore, at least in the portion overlapping the crotch elastic region ER, wrinkles formed in the absorbent core 11 (absorbent main body 10) due to the stretchability of the crotch elastic region ER are easily transmitted to the non-skin side waistline member 20 (inner layer sheet 23), making the wrinkles visible on the surface of the waistline member 20. This makes it easier for the user (wearer) to recognize that the diaper 1 has a good fit in the crotch region.

[0076] In the following, the portion of the main body joint 70 where adhesive is provided in the left-right central portion overlapping with the crotch elastic region ER is also referred to as the "central adhesive-presented portion 70c." In Figures 5A and 5B , the portion sandwiched between a pair of non-adhesive portions 75, 75 in the left-right direction (the portion surrounded by dashed lines in the left-right central portion) is the central adhesive-presented portion 70c, and this central adhesive-presented portion 70c joins the waistline member 20 (the inner layer sheet 23) and the absorbent main body 10 to each other. In addition, the portions of the main body joint 70 adjacent to the left-right outer sides of the non-adhesive portions 75 in the left-right direction (the portions surrounded by dashed lines on both left-right sides) are also referred to as "both adhesive-presented portions 70s."

[0077] In this case, the central adhesive-containing portion 70c is positioned so as to overlap the entire crotch elastic region ER in the left-right direction (see FIG. 5A ). That is, adhesive is applied to the sheet member (inner layer sheet 23) positioned closest to the skin throughout the entire portion overlapping the crotch elastic region ER in the left-right direction. Therefore, when the absorbent core 11 shrinks in the longitudinal direction due to the stretchability of the crotch elastic region ER, causing wrinkles, the influence of the wrinkles is transmitted to the waist member 20 (inner layer sheet 23) throughout the entire left-right area of ​​the crotch elastic region ER. This makes wrinkles formed in the crotch elastic region ER more visible in the crotch portion of the diaper 1 (crotch fit region IFR), thereby more easily impressing a user with a good fit.

[0078] Similarly, the central adhesive portion 70c is positioned so as to overlap the entire crotch elastic region ER in the longitudinal direction (see FIG. 5A ). That is, adhesive is applied to the sheet member (inner layer sheet 23) positioned closest to the skin throughout the entire overlapping portion with the crotch elastic region ER in the longitudinal direction. Therefore, when the absorbent core 11 shrinks in the longitudinal direction due to the stretchability of the crotch elastic region ER, the wrinkles are transmitted to the waist member 20 (inner layer sheet 23) throughout the entire longitudinal area of ​​the crotch elastic region ER. This makes the wrinkles formed in the crotch elastic region ER more visible in the crotch portion (crotch fit region IFR) of the diaper 1, thereby providing a good fit impression to the user.

[0079] The diaper 1 also has non-adhesive portions 75 adjacent to both outer sides of the central adhesive portion 70c in the left-right direction. As explained in Fig. 6B , when the crotch elastic region ER contracts, wrinkles form in the portion of the waistband member 20 (inner layer sheet 23) that is joined to the absorbent main body 10 at the central adhesive portion 70c, whereas wrinkles are less likely to form in the portions (non-adhesive portions 75) on both sides of the central adhesive portion 70c that are not joined to the absorbent main body 10. Therefore, it is possible to make wrinkles less noticeable overall while still providing a good fit in the crotch area (crotch fit region IFR).

[0080] In the diaper 1, the width of each of the non-adhesive portions 75 provided on both sides of the central adhesive-applied portion 70c in the left-right direction is greater than half the width of the crotch elastic region ER, thereby providing a sufficiently large area for the portions (non-adhesive portions 75) on both sides of the crotch elastic region ER where wrinkles are less likely to form. Therefore, even if wrinkles do form in the crotch area (crotch fit region IFR), the wrinkles are prevented from becoming excessively noticeable, and the underwear-like appearance of the diaper 1 is not easily impaired.

[0081] Furthermore, both left-right outer sides of the non-adhesive portion 75 further have adhesive-applied double-sided portions 70s (see FIG. 5A ). That is, the absorbent main body 10 has portions (adhesive-applied double-sided portions 70s) joined to the waistline member 20 (inner layer sheet 23) at both left-right end portions. If the absorbent main body 10 had large portions (non-adhesive portions 75) not joined to the waistline member 20 at both left-right end portions, the inner layer sheet 23 would curl at those end portions when the diaper 1 was worn, which could lead to wrinkles or the inner layer sheet 23 rolling up, resulting in poor fit. By providing adhesive-applied double-sided portions 70s on both left-right end portions of the non-adhesive portion 75, the inner layer sheet 23 is prevented from rolling up or becoming swollen near both left-right end portions of the absorbent main body 10. This improves the fit of the diaper 1 in the crotch area, particularly in the vicinity of the leg openings (leg openings LH), and also makes the diaper 1 appear more like underwear when worn.

[0082] Furthermore, no adhesive-free portions 75 are provided on either side (front and rear) of the central adhesive-present portion 70c in the longitudinal direction. In other words, the absorbent main body 10 is bonded to the waistline member 20 (inner layer sheet 23) with adhesive at the left-right center from the front end to the rear end in the front-to-rear direction. In the regions (front and rear) outside the crotch elastic region ER in the longitudinal direction, stretchability along the longitudinal direction is less likely to be exerted, and wrinkles are less likely to form in the absorbent core 11 even when the crotch elastic region ER contracts. Therefore, even if the absorbent main body 10 and waistline member 20 (inner layer sheet 23) are bonded in this region, wrinkles are less likely to form in the waistline member 20. Conversely, if the absorbent main body 10 and the waistline member 20 (inner layer sheet 23) were not joined in the regions longitudinally outboard (front and rear) of the crotch elastic region ER (if the non-existent portions 75 were provided), the inner layer sheet 23 would separate from the waistline member 20 and float up against the skin in the thickness direction, resulting in a stiff, diaper-like appearance. In the diaper 1, by firmly joining the absorbent main body 10 and the waistline member 20 (inner layer sheet 23) in the regions longitudinally outboard (front and rear) of the crotch elastic region ER, the floating of the waistline member 20 (inner layer sheet 23) when worn is suppressed, making the diaper appear more like underwear.

[0083] Fig. 8 is an enlarged cross-sectional view of Fig. 5B. In the thickness direction of the diaper 1, the sheet member (back sheet 13) located adjacent to the skin side of the crotch elastic member 40 (crotch elastic region ER) and the sheet member (inner sheet 23) located furthest from the skin side in the thickness direction at the longitudinal center position CL have portions that are not joined to each other. In Fig. 8, the inner sheet 23 and the back sheet 13 are not joined to each other at least in the non-adhesive portion 75 where no adhesive is provided.

[0084] In the diaper 1, the backsheet 13 and the elastic member cover sheet 17 are bonded to each other via an adhesive applied to the surface of the crotch elastic member 40. Therefore, when the crotch elastic region ER contracts along the longitudinal direction, wrinkles are likely to form not only on the non-skin-side elastic member cover sheet 17 but also on the skin-side backsheet 13. Meanwhile, the backsheet 13 and the inner layer sheet 23 provided on the non-skin-side have portions (non-existing portions 75) where they are not bonded to each other in the thickness direction, which prevents wrinkles formed in the backsheet 13 from being transmitted to the non-skin-side inner layer sheet 23. This makes it difficult for wrinkles to form in the waistband member 20 (inner layer sheet 23) at least at the longitudinal center position CL. This allows the diaper 1 to have an underwear-like appearance when worn.

[0085] Even if wrinkles are formed in the backsheet 13 due to longitudinal contraction of the crotch elastic region ER, the provision of the non-existent portions 75 on both lateral sides of the crotch elastic region ER prevents the effects of the wrinkles from spreading beyond the non-existent portions 75 to the lateral sides. This prevents wrinkles from forming over a wider area in the crotch area, making the appearance of the diaper 1 when worn more likely to resemble underwear.

[0086] Furthermore, among the sheet components constituting the absorbent main body 10, the side sheets 16 and the elastic member cover sheets 17 are both positioned closest to the skin, but these sheets 16, 17 are configured as independent sheet components. In other words, the sheet component positioned closest to the skin of the absorbent main body 10 is discontinuous between the elastic member cover sheet 17, which is positioned in the center in the lateral direction, and the side sheets 16, which are positioned on both sides. With this configuration, even if wrinkles are formed in the elastic member cover sheet 17 due to contraction of the crotch elastic region ER, the influence of the wrinkles is unlikely to be transmitted from the elastic member cover sheet 17 to the side sheets 16. In other words, even if the crotch elastic region ER contracts, wrinkles are unlikely to form in the side sheets 16. This prevents the range of wrinkles formed in the waistband member 20 of the diaper 1 from spreading laterally, making wrinkles less noticeable in the crotch region. This makes the diaper 1 appear more like underwear when worn.

[0087] Furthermore, among the sheet members arranged closest to the skin of the absorbent main body 10, the elastic member cover sheet 17 overlapping the crotch elastic region ER in the lateral center has portions at both lateral ends free of adhesive. In the lateral direction of FIG. 8 , both lateral ends 17e of the elastic member cover sheet 17 overlap with the adhesive-free portions 75, and these lateral ends 17e form so-called dry edges, i.e., no adhesive is applied. With this configuration, even if wrinkles form in the elastic member cover sheet 17 due to contraction of the crotch elastic region ER, the dry edges (both lateral ends 17e) on both lateral sides prevent the influence of the wrinkles from being transmitted outward in the lateral direction. This prevents the range of wrinkles formed in the waistband member 20 of the diaper 1 from spreading laterally, making the wrinkles less noticeable in the crotch region. This allows the diaper 1 to have an appearance similar to underwear when worn.

[0088] The absorbent core 11 of the diaper 1 has a constricted portion 11c in the longitudinal center that is narrower in the left-right direction than the opposite longitudinal ends (see FIG. 4A ). The presence of this constricted portion 11c prevents the edges of the opposite ends of the absorbent core 11 from interfering with the wearer's crotch area (groin area) when the diaper 1 is worn, improving the fit.

[0089] In the diaper 1, the crotch elastic region ER is provided in the portion of the absorbent core 11 where the width in the left-right direction is narrowest. In other words, the position where the width of the constricted portion 11c in the left-right direction is narrowest (11n in FIG. 4A) overlaps the crotch elastic region ER in the longitudinal direction. As explained above, when the crotch elastic region ER contracts while the diaper 1 is being worn, wrinkles are likely to form in the crotch fit region IFR. In this embodiment, the width of the absorbent core 11 (the constricted portion 11c) is narrowest in the crotch fit region IFR, where wrinkles are likely to form. Therefore, compared to when wrinkles form in a wider region of the absorbent core 11, wrinkles are less likely to be excessively large and noticeable. This allows the diaper 1 to appear more like underwear when worn.

[0090] Furthermore, the diaper 1 has at least two sheet members on the non-skin side of the crotch elastic member 40 (crotch elastic region ER) in the thickness direction. In FIG. 8, an elastic member cover sheet 17 (referred to as the first sheet member) is provided adjacent to the non-skin side of the crotch elastic member 40, and an inner layer sheet 23 (referred to as the second sheet member) is further provided on the non-skin side of the elastic member cover sheet 17. In this case, it is preferable that the average basis weight of the first sheet member is different from that of the second sheet member. The basis weight (g / m ２ ) is an indicator of weight per unit area.

[0091] Sheet members with different basis weights often have different stiffnesses and thicknesses, which means that they are likely to wrinkle differently. Therefore, by stacking a first sheet member (skin-side) and a second sheet member (non-skin-side) with different basis weights in the thickness direction, it is possible to prevent wrinkles formed in the first sheet member from being directly transmitted to the second sheet member. For example, even if wrinkles are formed in the skin-side elastic member cover sheet 17 (first sheet member) when the crotch elastic region ER of the diaper 1 contracts, the likelihood of the formed wrinkles being directly transmitted to the non-skin-side inner layer sheet 23 (second sheet member) can be reduced. This makes wrinkles less noticeable in the crotch area, making the diaper 1 appear more like underwear.

[0092] In this case, it is preferable that the basis weight of the second sheet member on the non-skin side is greater than the basis weight of the first sheet member on the skin side. Generally, sheet members with a larger basis weight tend to be more rigid than sheet members with a smaller basis weight. Therefore, by placing a sheet member with a larger basis weight on the non-skin side, it is possible to more easily prevent large wrinkles from forming on the non-skin side. This makes wrinkles less noticeable in the crotch area, making the appearance of the diaper 1 more likely to resemble underwear.

[0093] Furthermore, it is preferable that the average fiber width of the fibers constituting the first sheet member (e.g., the elastic member cover sheet 17) differ from the average fiber width of the fibers constituting the second sheet member (e.g., the inner layer sheet 23). Generally, fibers with a wider average fiber width are less likely to bend and form creases. Therefore, laminating first and second sheet members with different average fiber widths can help prevent wrinkles formed in the first sheet member from propagating directly to the second sheet member. For example, even if wrinkles form in the skin-side elastic member cover sheet 17 (first sheet member) when the crotch elastic region ER of the diaper 1 contracts, the likelihood of the wrinkles being propagated directly to the non-skin-side inner layer sheet 23 (second sheet member) can be reduced. This reduces the visibility of wrinkles in the crotch area, making the diaper 1 appear more like underwear.

[0094] The average fiber width of the fibers can be measured as a fiber width value using, for example, Kajaani FiberLab °fiber properties (off-line) manufactured by Metso Automation.

[0095] Furthermore, it is preferable that the fiber orientation direction of the first sheet member (e.g., the elastic member cover sheet 17) and the fiber orientation direction of the second sheet member (e.g., the inner layer sheet 23) intersect with each other. For example, in the diaper 1, the fiber orientation direction of the first sheet member (the elastic member cover sheet 17) is along the longitudinal direction, while the fiber orientation direction of the second sheet member (the inner layer sheet 23) is along the left-right direction, intersecting with each other. In this case, the stretchability of the first sheet member along the longitudinal direction is likely to differ from the stretchability of the second sheet member along the longitudinal direction, and the likelihood of wrinkle formation when the crotch elastic region ER contracts along the longitudinal direction is also likely to differ. Therefore, even if wrinkles form in the first sheet member, the likelihood of the formed wrinkles being directly transmitted to the second sheet member can be reduced. This reduces the likelihood of wrinkles being noticeable in the crotch area, making the diaper 1 appear more like underwear.

[0096] The fiber orientation is a concept consisting of the fiber orientation angle and orientation strength, and the fiber orientation direction can be measured, for example, by the following method. First, the sheet member to be measured is cut to a predetermined size and placed so that the longitudinal direction (or left-right direction) can be determined. Using a microscope (for example, a scanning electron microscope such as JCM-5100 manufactured by JEOL Ltd.), an enlarged image from a direction perpendicular to the measurement surface of the sample is captured and printed, and the fibers are traced on a transparent PET sheet. The enlarged image is an image enlarged to a magnification that allows measurement of 10 or more fibers, and the magnification is, for example, 50 to 300 times. The image is imported into a personal computer and binarized using nexusNewQube (standalone version) image processing software manufactured by Nexus Corporation. The orientation angle and orientation strength are obtained from the binarized image using Fiber Orientation Analysis 8.13 Single, a fiber orientation analysis program. The orientation angle is the angle at which the fibers are most oriented, and the orientation strength is the strength at that orientation angle. The closer the orientation angle is to 90°, the more oriented the fibers are in the longitudinal direction (or left-right direction). Furthermore, the greater the orientation strength, the more uniform the fibers are. An orientation strength of 1.05 or higher is considered to be oriented. The measurement is repeated several times (for example, 3 to 5 times) and the average value is calculated.

[0097] Furthermore, among the multiple crotch elastic members 40 (41-45) defining the crotch elastic region ER of the diaper 1, one elastic member is designated as the first crotch elastic member, and the elastic member located adjacent to and on the left-right outer side of the first crotch elastic member is designated as the second crotch elastic member. For example, if the crotch elastic member 43 located in the left-right center is designated as the first crotch elastic member, the crotch elastic members 42, 44 adjacent to it on the left-right outer side are designated as the second crotch elastic members. In this case, it is preferable that the force required to longitudinally stretch the first crotch elastic member by a unit length is greater than the force required to longitudinally stretch the second crotch elastic member by a unit length. In other words, it is preferable that the stress of the multiple crotch elastic members 41-45 is smaller toward the left-right outer side.

[0098] With this configuration, the elasticity of the crotch elastic region ER becomes weaker toward the outside in the left-right direction, so that when the crotch elastic region ER contracts in the longitudinal direction, wrinkles formed toward the outside in the left-right direction become smaller. Furthermore, wrinkles are less noticeable in the region outside the crotch elastic region ER in the left-right direction (region overlapping with the non-existent portion 75) (see FIG. 6B ). This allows the appearance of the diaper 1 to be more similar to underwear.

[0099] The force required to stretch the crotch elastic members by a unit length in the longitudinal direction can be measured, for example, as follows. First, the backsheet 13 and elastic member cover sheet 17 sandwiching the crotch elastic members 40 (41-45) are cut out so as to include the entire crotch elastic region ER. Then, for each of the multiple crotch elastic members 40, a predetermined width (e.g., 1.0 mm) is cut from the crotch elastic member 40 on both sides in the lateral direction to obtain a test specimen approximately 2 mm wide, centered on the crotch elastic member 40. Next, both longitudinal ends of the test specimen in its natural state are clamped between the chucks of a known tensile testing machine (e.g., an Instron universal testing machine), and the distance Lc between the chucks is adjusted to 100 mm. From this state, the distance Lc is increased at a predetermined speed (100 mm / min) until the test specimen is stretched by a predetermined length. For example, the test specimen is stretched to a length 0.9 times its maximum extension. That is, the test piece is stretched until its longitudinal length is 0.9 times its original length. The test piece is then contracted to its original length. This cycle is repeated twice, and in the second cycle, the test piece is stretched to 0.8 times its maximum length, and the magnitude of the force (N) at the time of stretching is measured. This measurement is repeated a predetermined number of times (e.g., three times) to obtain the stretching force (contraction force) of the test piece.

[0100] (Modifications of Diaper 1) The diaper 1 may be modified as follows. FIG. 9 shows a plan view and a cross-sectional view of a modified diaper 1 in an unfolded and stretched state. In the modified diaper 1, the arrangement of the multiple crotch elastic members 40 (41-45) constituting the crotch elastic region ER differs from that of the above-described embodiment. Specifically, in the modified diaper 1, the multiple crotch elastic members 40 (41-45) are located closer to the skin than the absorbent core 11 (core wrap sheet 18, not shown in FIG. 9) and closer to the skin than the backsheet 13 in the thickness direction. Furthermore, the modified diaper 1 does not include an elastic member cover sheet 17. The rest of the configuration is the same as that of the diaper 1 described with reference to FIG. 5 and other figures.

[0101] In the diaper 1 of this modification, the absorbent main body 10 and the waistband member 20 are joined to each other by a main body joining portion 70. Furthermore, there are non-adhesive portions 75 on both lateral sides of the crotch elastic region ER. That is, among the sheet members located on the non-skin side of the crotch elastic member 40 (crotch elastic region ER), the inner layer sheet 23 closest to the skin is not joined to the adjacent back sheet 13 on the skin side at the non-adhesive portion 75. Therefore, even if the back sheet 13 shrinks in the longitudinal direction due to the expansion and contraction of the crotch elastic region ER, the effect of the wrinkles is less likely to be transmitted to the non-skin side inner layer sheet 23 at the non-adhesive portion 75, and the wrinkles are less noticeable in the crotch portion of the waistband member 20 (crotch fit region IFR). This allows the appearance of the diaper 1 of this modification to be more underwear-like.

[0102] Second Embodiment In the second embodiment, a pants-type diaper 2 (hereinafter also referred to as "diaper 2") having a configuration partially different from that of the first embodiment will be described. Fig. 10 is a three-view diagram illustrating the configuration of the diaper 2 of the second embodiment.

[0103] The diaper 2 of the second embodiment has a liquid-absorbent absorbent main body 10 and a waistband member 20 arranged on the non-skin side of the absorbent main body 10. However, the configuration of the waistband member 20 of the diaper 2 differs from that of the diaper 1 of the first embodiment. Specifically, the waistband member 20 of the diaper 2 has an outer layer sheet 27 arranged on the non-skin side of the inner layer sheet 23. The outer layer sheet 27 is a sheet that is continuous in the longitudinal direction from one end (front side) to the other end (rear side), and corresponds to a sheet member in which the ventral side outer layer sheet 21 and the dorsal side outer layer sheet 22 of the diaper 1 are integrated. The configuration other than the outer layer sheet 27 is basically the same as that of the diaper 1.

[0104] In the diaper 2, the absorbent main body 10 and the waistline member 20 are joined together by a main body joining portion 70 similar to that of the diaper 1. Furthermore, there are non-adhesive portions 75 on both lateral sides of the crotch elastic region ER. Considering that the inner layer sheet 23 and the outer layer sheet 27 of the waistline member 20 of the diaper 2 are joined together and integrated, the outer layer sheet 27 (inner layer sheet 23) closest to the skin, among the sheet members provided on the non-skin side of the crotch elastic member 40 (crotch elastic region ER), is not joined to the adjacent elastic member cover sheet 17 on the skin side at the non-adhesive portion 75. Therefore, even if the elastic member cover sheet 17 shrinks in the longitudinal direction due to the expansion and contraction of the crotch elastic region ER, the effect of the wrinkles is unlikely to be transmitted to the non-skin-side outer layer sheet 27 (inner layer sheet 23) in the non-existent portion 75, and the wrinkles are less noticeable in the crotch portion (crotch fit region IFR) of the waistband member 20. This allows the appearance of the diaper 2 to be more similar to underwear.

[0105] Furthermore, when the inner layer sheet 23 and the outer layer sheet 27 are not integrated by the waistband member 20 of the diaper 2, the sheet members provided on the non-skin side of the crotch elastic member 40 (crotch elastic region ER) may have a portion where the outer layer sheet 27 closest to the skin side is not joined to the inner layer sheet 23 adjacent to it. That is, the outer layer sheet 27 may have a non-adhesive portion (not shown) where no adhesive is present, and the inner layer sheet 23 and the outer layer sheet 27 are not joined at this non-adhesive portion. For example, even if the elastic member cover sheet 17 shrinks in the longitudinal direction due to the expansion and contraction of the crotch elastic region ER, and wrinkles are formed, even if the effect of the wrinkles is transmitted to the inner layer sheet 23, the non-adhesive portion will be less likely to transmit the wrinkles from the inner layer sheet 23 to the outer layer sheet 27, and therefore wrinkles will be less likely to form in the outer layer sheet 27. Therefore, in this case as well, wrinkles are less noticeable in the crotch portion of the waistband member 20 (crotch fitting region IFR), making the appearance of the diaper 2 more likely to look like underwear.

[0106] Third Embodiment In the third embodiment, a pants-type diaper 3 (hereinafter also referred to as "diaper 3") having a configuration partially different from that of the first and second embodiments will be described. Fig. 11 is a three-view diagram illustrating the configuration of the diaper 3 of the third embodiment.

[0107] The diaper 3 of the third embodiment includes a liquid-absorbent main body 10 and a waistline member 20 disposed on the non-skin side of the absorbent main body 10. However, in the diaper 3, the waistline member 20 is divided into a front side (ventral side) and a rear side (back side), and is composed of two members, a front waistline portion 20f and a rear waistline portion 20b. In other words, the diaper 3 is a pants-type absorbent article having a so-called three-piece structure in which the front waistline portion 20f and the rear waistline portion 20b are disposed with a gap between them in the longitudinal direction, and the absorbent main body 10 is disposed between the front waistline portion 20f and the rear waistline portion 20b.

[0108] As shown in the A3-A3 cross-sectional view of Fig. 11 , the absorbent main body 10 of the diaper 3 has a plurality of crotch elastic members 40 stretched in the longitudinal direction on the non-skin side of the absorbent core 11 in the thickness direction and on the skin side of the backsheet 13, and these crotch elastic members 40 define a crotch elastic region ER. In addition, the side sheet 16 is continuous from one side to the other in the left-right direction (see the A3-A3 cross-sectional view of Fig. 11 ), and the leakage prevention walls 60 on both the left and right sides are formed by a single side sheet 16. The rest of the configuration is substantially the same as that of the absorbent main body 10 of the diaper 1.

[0109] The front waistline portion 20f of the diaper 3 comprises a ventral outer sheet 21, a ventral inner sheet 23f disposed on the skin side of the ventral outer sheet 21 and having substantially the same shape as the ventral outer sheet 21, and a plurality of waistline elastic members 24 disposed between the ventral outer sheet 21 and the ventral inner sheet 23f. Similarly, the rear waistline portion 20b of the diaper 3 comprises a dorsal outer sheet 22, a dorsal inner sheet 23b disposed on the skin side of the dorsal outer sheet 22 and having substantially the same shape as the dorsal outer sheet 22, and a plurality of waistline elastic members 25 and buttocks elastic members 26 disposed between the dorsal outer sheet 22 and the dorsal inner sheet 23b.

[0110] In the crotch region (crotch fit region IFR) of the diaper 3, the non-skin-facing side of the absorbent main body 10 constitutes the outermost layer. That is, in the crotch region (crotch fit region IFR) of the diaper 3, the side sheets 16 of the absorbent main body 10 are the sheet members arranged closest to the skin. The side sheets 16 and the back sheet 13 adjacent to the skin side thereof are joined to each other by inner-back joining sections 80 formed with an adhesive such as a hot melt adhesive. The inner-back joining sections 80 are formed by applying adhesive to the areas indicated by the diagonally shaded areas slanting downward to the right in the plan view of FIG. 11 . On the other hand, a pair of adhesive-free sections 85, where no adhesive is present, are formed on both lateral sides of the crotch elastic region ER. That is, the side sheets 16 and the back sheet 13 are not joined to each other at the adhesive-free sections 85.

[0111] When the diaper 3 is worn, the backsheet 13 contracts in the longitudinal direction due to the elasticity of the crotch elastic region ER (crotch elastic member 40), resulting in wrinkles being formed in the backsheet 13. The wrinkles formed in the backsheet 13 are transmitted to the non-skin-side sidesheet 16 via the inner-back joint 80, but at the non-existent portion 85, the wrinkles formed in the backsheet 13 are unlikely to be transmitted to the sidesheet 16. Therefore, wrinkles are unlikely to form in the region of the sidesheet 16 that overlaps with the non-existent portion 85 when viewed in the thickness direction. In other words, wrinkles are less visible in the crotch region (crotch fit region IFR), which makes the appearance of the diaper 3 more likely to resemble underwear.

[0112] ===Other=== The above embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention may be modified or improved without departing from the spirit thereof, and it goes without saying that the present invention includes equivalents thereof.

[0113] DESCRIPTION OF SYMBOLS 1 Diaper (first embodiment, pants-type disposable diaper, pants-type absorbent article), 2 Diaper (second embodiment), 3 Diaper (third embodiment), 5 Side joint portion, 10 Absorbent main body, 11 Absorbent core, 11c Waistband elastic member, 12 Top sheet, 13 Back sheet, 15 Intermediate sheet, 16 Side sheet, 17 Elastic member cover sheet, 18 Core wrap sheet, 19 Leg gather elastic member, 20 Waistband member (exterior member), 20f Front waistband portion, 20b Rear waistband portion, 21 Ventral outer layer sheet, 22 Dorsal outer layer sheet, 23 Inner layer sheet, 23f Ventral inner layer sheet, 23b Dorsal inner layer sheet, 24 Waistband elastic member (ventral side), 25 Waistband elastic member (dorsal side), 26 Buttocks elastic member, 27 Outer layer sheet, 31 Cover sheet, 32 Cover sheet, 40 Crotch elastic member, 41-45 Crotch elastic member, 60 Leakage preventing wall portion, 61 Leakage preventing wall elastic member, 70 Main body joint portion, 70c Central adhesive-present portion, 70s Both side adhesive-present portions, 75 Non-present portion, 80 Inner back joint portion, 85 Non-present portion, BH Waist opening, LH Leg opening, CL Central position (longitudinal direction), ER Crotch elastic region

Claims

1. A pants-type absorbent article having an absorbent main body with an absorbent core, which has longitudinal, lateral, and thickness directions that intersect with one another when in an unfolded and stretched state, and which has a crotch elastic region that is defined by a crotch elastic member that is located closer to the skin than the absorbent core and stretches along the longitudinal direction, and which has lateral elastic members that are continuous from one end to the other in the lateral direction, and which does not have a portion where the crotch elastic region and the lateral elastic member overlap in the longitudinal direction, and which has a non-existent portion that overlaps with the absorbent core when viewed in the thickness direction and that overlaps with the crotch elastic region in the longitudinal direction, where the adhesive is not present in the sheet member that is located furthest from the skin among the sheet members that are located closer to the skin than the crotch elastic member, and which has a length in the longitudinal direction of the non-existent portion that is at least half the length of the crotch elastic region in the longitudinal direction, or a length in the lateral direction of the non-existent portion that is at least half the length of the crotch elastic region in the lateral direction.

2. A pants-type absorbent article as described in claim 1, characterized in that when viewed in the thickness direction, the part overlapping with the crotch elastic region has a central adhesive portion where adhesive is provided on the sheet member provided closest to the skin.

3. A pants-type absorbent article as described in claim 2, characterized in that the sheet member provided closest to the skin has the central adhesive portion over the entire portion that overlaps with the crotch elastic region in the left-right direction.

4. A pants-type absorbent article as described in claim 2, characterized in that the sheet member provided on the side furthest from the skin has the central adhesive portion over the entire portion that overlaps with the crotch elastic region in the longitudinal direction.

5. A pants-type absorbent article as claimed in claim 2, characterized in that the sheet member provided closest to the skin has the adhesive-free portions adjacent to both outer sides of the central adhesive-present portion in the left-right direction.

6. A pants-type absorbent article as claimed in claim 5, characterized in that it has adhesive-applied portions on both sides, in the left-right direction, further outward than the non-adhesive portions adjacent to both outer sides of the central adhesive-applied portion, in which adhesive is applied to the sheet member provided closest to the skin.

7. A pants-type absorbent article according to claim 2, characterized in that, in the longitudinal direction, there are no adhesive-free areas on either side of the central adhesive-present area.

8. A pants-type absorbent article according to any one of claims 1 to 7, characterized in that in the thickness direction, there is a portion where the sheet member arranged adjacent to the skin side of the crotch elastic member and the sheet member arranged furthest from the skin side are not joined.

9. A pants-type absorbent article according to any one of claims 1 to 7, characterized in that the absorbent core has a waisted portion in the center in the longitudinal direction that is narrower in width in the left-right direction than both ends in the longitudinal direction, and the position in the longitudinal direction where the width of the waisted portion in the left-right direction is narrowest overlaps with the crotch elastic region.

10. A pants-type absorbent article according to any one of claims 1 to 7, characterized in that the average basis weight of the first sheet member provided on the non-skin side of the crotch elastic member in the thickness direction is different from the average basis weight of the second sheet member provided on the non-skin side of the first sheet member.

11. A pants-type absorbent article according to claim 10, characterized in that the average basis weight of the second sheet member is greater than the average basis weight of the first sheet member.

12. A pants-type absorbent article according to claim 10, characterized in that the average fiber width of the fibers constituting the first sheet member is different from the average fiber width of the fibers constituting the second sheet member.

13. A pants-type absorbent article according to claim 10, characterized in that the fiber orientation direction of the first sheet member and the fiber orientation direction of the second sheet member intersect with each other.

14. A pants-type absorbent article as claimed in any one of claims 1 to 7, wherein the crotch elastic members are provided in a plurality at intervals in the left-right direction, the plurality of crotch elastic members comprising a first crotch elastic member and a second crotch elastic member arranged adjacent to the outside of the first crotch elastic member in the left-right direction, and wherein the force required to stretch the first crotch elastic member by a unit length in the longitudinal direction is greater than the force required to stretch the second crotch elastic member by a unit length in the longitudinal direction.

15. A pants-type absorbent article according to any one of claims 1 to 7, characterized in that the sheet member arranged on the side of the absorbent main body closest to the skin is discontinuous between the center and both side portions in the left-right direction.

16. A pants-type absorbent article as described in claim 15, characterized in that, of the sheet members arranged on the side furthest from the skin of the absorbent main body, the sheet member that overlaps with the crotch elastic member in the center in the left-right direction has portions at both ends in the left-right direction where no adhesive is provided.

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