Absorbent article

Abstract

Provided is an absorbent article (1) comprising an absorbent body (10), one-side torso member (30), an opposite-side torso member (40), and a pair of side joint parts (30s, 40s). The absorbent article (1) in an unfolded and stretched state has a shape symmetrical in the front-back direction. A crotch length (F) is longer than a torso length (G) and shorter than twice the torso length (G), where the crotch length (F) is the length between an end (40ed) of the opposite-side torso member (40) on one side in the front-back direction and an end (30ed) of the one-side torso member (30) on the opposite side in the front-back direction, and the torso length (G) is the length between an end (10es) of the absorbent body (10) on one side in the left-right direction and an end (30sl) of the side joint part (30s) on the opposite side in the left-right direction.

Description

absorbent articles

[0001] The present invention relates to an absorbent article.

[0002] Conventionally, there has been known a technique for preventing the wrong person from putting on an absorbent article such as a pants-type diaper by making the diaper symmetrical from front to back (back to ventral side). For example, Patent Document 1 discloses a technique for a pants-type diaper in which a stretchable leg-opening sheet is continuously provided along the leg-openings, and which can be worn comfortably either forward or backward.

[0003] Japanese Patent Application Laid-Open No. 2005-287699

[0004] However, among absorbent articles, so-called three-piece pants-type diapers, which are composed of three components, i.e., an absorbent main body, a ventral waist member, and a rear waist member, have difficulty in achieving both front-to-rear symmetry and good wearability. For example, in a three-piece pants-type diaper in an unfolded state, if the distance between the ventral waist member and the rear waist member in the front-to-rear direction is narrow, the circumference of the leg openings becomes short, making it difficult to insert the wearer's legs. On the other hand, if the distance between the ventral waist member and the rear waist member in the front-to-rear direction is wide, there are problems such as the buttocks easily protruding from the rear waist member when worn.

[0005] The present invention has been made in consideration of the above-mentioned conventional problems, and its object is to provide a three-piece diaper with a front-to-back symmetrical shape that allows easy leg insertion through the leg openings and prevents the buttocks from protruding when worn.

[0006] The main invention for achieving the above object is an absorbent article having a front-to-rear direction and a left-to-right direction that intersect each other in an unfolded state, the absorbent article comprising an absorbent main body, a one-side waistline member arranged on one side of the absorbent main body in the front-to-rear direction, and a second-side waistline member arranged on the other side of the absorbent main body in the front-to-rear direction, and a pair of side joints joining both sides in the left-to-right direction of the one-side waistline member and the other-side waistline member, the absorbent article having a shape that is symmetrical in the front-to-rear direction in an unfolded and stretched state, and wherein, when the distance between the other end of the one-side waistline member and one end of the other-side waistline member in the front-to-rear direction is defined as the crotch distance, and the distance between the one end of the absorbent main body and the other end of the side joint provided on one side of the one-side waistline member or the other-side waistline member in the left-to-right direction is defined as the waistline distance, the crotch distance is longer than the waistline distance and shorter than twice the waistline distance. 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 three-piece diaper having a front-to-back symmetrical shape, which allows easy leg insertion through the leg openings and prevents the buttocks from protruding when worn.

[0008] 1 is a schematic perspective view of the diaper 1; 2 is a plan view of the diaper 1 in an unfolded and stretched state, as viewed from the skin side in the thickness direction; 3 is a schematic cross-sectional view taken along line A-A in FIG. 2; 4A is a plan view of the absorbent main body 10, and 4B is a schematic cross-sectional view of the absorbent main body 10; 5 is a diagram illustrating the positional relationship of one waistline member 30 and the other waistline member 40 with respect to the absorbent main body 10; 6 is a diagram illustrating the relationship between the crotch distance F and the waistline distance G; 7 is a diagram illustrating a case where the one waistline member 30 and the other waistline member 40 of the diaper 1 are substantially trapezoidal; 8 is a diagram illustrating an enlarged view of a portion of the one waistline member 30 and the absorbent main body 10 in the unfolded and stretched state of the diaper 1; 9A to 9C are diagrams illustrating the joining of the one waistline member 30 and the absorbent main body 10.

[0009] At least the following matters will become clear from the description of this specification and the accompanying drawings.

[0010] (Aspect 1) An absorbent article having a front-to-rear direction and a left-to-right direction that intersect each other in an unfolded state, comprising an absorbent main body, a one-side waistline member arranged on one side of the absorbent main body in the front-to-rear direction, and a second-side waistline member arranged on the other side of the absorbent main body in the front-to-rear direction, and a pair of side joints joining both sides in the left-to-right direction of the one-side waistline member and the other-side waistline member, wherein the absorbent article has a shape that is symmetrical in the front-to-rear direction in an unfolded and stretched state, and wherein, when the distance between the other end of the one-side waistline member and the one end of the other-side waistline member in the front-to-rear direction is defined as a crotch distance, and the distance between the one end of the absorbent main body and the other end of the side joint provided on one side of the one-side waistline member or the other-side waistline member in the left-to-right direction is defined as a waistline distance, the crotch distance is longer than the waistline distance and shorter than twice the waistline distance.

[0011] According to the absorbent article of aspect 1, the front-to-back symmetrical shape eliminates the need to distinguish between the ventral and dorsal sides, reducing the strain on the wearer when putting it on. Furthermore, compared to when the crotch distance (F) is equal to or less than the waist circumference distance (G) (F≦G), the circumference of the leg openings is less likely to be excessively short in the crotch area, preventing the wearer's legs from getting caught when passing them through the leg openings. Furthermore, compared to when the crotch distance (F) is twice the waist circumference distance (G) or more (F≧2G), the distance from the crotch to the lower end of the waist member is less likely to be excessively wide, preventing the wearer's buttocks from protruding from the waist member on the back side of the wearer.

[0012] (Aspect 2) The absorbent article according to aspect 1, wherein in a deployed and stretched state, the width of the one waistline member and the other waistline member in the front-to-rear direction is shorter than the waistline distance.

[0013] According to the absorbent article of aspect 2, the distance required to pass the legs from the waist opening to the leg openings when putting on the absorbent article is shorter than when the width (h1) of one waist member is equal to or greater than the waist circumference distance (G) (h1≧G). This reduces the probability that the wearer's legs will get caught in the waist member, making it easier to put the legs on and improving fit.

[0014] (Aspect 3) The absorbent article according to Aspect 1 or 2, wherein in the unfolded and stretched state, the distance between one end of the one-side waistline member and one end of the absorbent main body in the front-to-rear direction is shorter than the distance between one end of the absorbent main body and the other end of the one-side waistline member.

[0015] According to the absorbent article of aspect 3, the portion (b) of the waistband member that does not overlap with the absorbent main body is less rigid than the overlapping portion (c) and is therefore more likely to shrink left and right, so that the absorbent article needs to be spread out widely when worn. However, by making the area of ​​the portion (b) that is more likely to shrink relatively small compared to the reverse case, the waistband member (waistband opening) can be more easily spread out left and right.

[0016] (Aspect 4) The absorbent article according to any one of Aspects 1 to 3, wherein the absorbent main body has an absorbent core, and in an unfolded and stretched state, the distance between one end of the one-side waistline member and one end of the absorbent main body in the front-to-rear direction is longer than the distance between one end of the absorbent core and the other end of the one-side waistline member.

[0017] According to the absorbent article of aspect 4, by narrowing the width of the portion (d) of the waistband member that overlaps with the absorbent core in the front-to-back direction and thereby has high rigidity, the waistband member becomes more likely to deform three-dimensionally to conform to the contours of the wearer's body (waistline), thereby improving fit.

[0018] (Aspect 5) The absorbent article according to any one of Aspects 1 to 4, wherein the one waistline member and the other waistline member are rectangular.

[0019] According to the absorbent article of aspect 5, the waistband member is rectangular and has no unnecessary protrusions, etc., so that the wearer can move their legs freely even while wearing the absorbent article. For example, it is possible to reduce the occurrence of problems such as interference with the protrusions when moving the legs back and forth while walking.

[0020] (Aspect 6) The absorbent article according to any one of Aspects 1 to 5, wherein the one-side waistline member and the other-side waistline member are provided with a plurality of waistline stretch members that stretch in the left-right direction and are spaced apart in the front-to-rear direction, and in an unfolded and stretched state, in the area where the one-side waistline member and the absorbent main body overlap in the front-to-rear direction, the distance between the waistline stretch member located on the other side of the one-side waistline member and the other end of the one-side waistline member is greater than the maximum value of the pitch between two adjacent waistline stretch members.

[0021] According to the absorbent article of aspect 6, a predetermined distance is easily ensured between the elastic member provided at the lower end (the other-most side) of the waistband member and the periphery of the leg openings. Therefore, when the wearer puts on the absorbent article and passes their legs through the leg openings, their toes are less likely to get caught on the periphery of the leg openings. This makes it easier to pass their legs through the leg openings.

[0022] (Aspect 7) An absorbent article according to any one of Aspects 1 to 6, wherein the absorbent main body has an absorbent core, and the absorbent core has a constricted portion between one end and the other end in the front-to-rear direction, the constricted portion having a narrower width in the left-to-right direction, and when viewed in the thickness direction in an unfolded and stretched state, the constricted portion has portions that overlap with each of the one-side waistline member and the other-side waistline member.

[0023] According to the absorbent article of Aspect 7, the portion of the waistband member that overlaps with the constricted portion of the absorbent core is less susceptible to the rigidity of the absorbent core and is therefore more likely to deform. Therefore, the waistband member is more likely to deform and fit to the contours of the wearer's body. Furthermore, the more easily deformed the region near the periphery of the leg openings is, making it easier to insert the legs through the leg openings.

[0024] (Aspect 8) An absorbent article according to any one of Aspects 1 to 7, wherein the absorbent main body has an absorbent core and main body joints that join the absorbent main body to each of the one-side waistline member and the other-side waistline member with an adhesive, the main body joints having a central joint located in the center in the left-right direction and side joints located on both sides of the central joint in the left-right direction, the basis weight of the adhesive in the central joint being greater than the basis weight of the adhesive in the side joints, and the boundary between the central joint and the side joints being located outside the absorbent core in the left-right direction.

[0025] According to the absorbent article of aspect 8, the boundary between the central joint and the two side joints does not overlap with the highly rigid absorbent core, so that the starting point of bending deformation is easily formed based on the difference in rigidity (difference in basis weight) that occurs at the boundary, making it easier for the absorbent article to deform and fit in accordance with the contours of the body.

[0026] Embodiments The absorbent article according to the present invention will be described by taking a disposable diaper (hereinafter also referred to as "diaper 1") as an example. Diaper 1 is a pants-type absorbent article for adults, intended for use by adults who can put it on themselves and by care recipients who can put it on with the assistance of a caregiver. The absorbent article according to the present invention also includes pants-type napkins, panty liners, and other absorbent articles.

[0027] <Configuration of Diaper 1> Fig. 1 is a schematic perspective view of the diaper 1. Fig. 2 is a plan view of the diaper 1 in an unfolded and stretched state, as viewed from the skin side in the thickness direction. Fig. 3 is a schematic cross-sectional view taken along line A-A in Fig. 2. The "stretched state" of the diaper 1 refers to a state in which the entire diaper 1 (the entire product) is stretched without wrinkles, specifically, a state in which the dimensions of each component constituting the diaper 1 (e.g., the absorbent main body 10 and waistband member 20, which will be described later) are stretched to the same dimensions as or close to the dimensions of the individual components.

[0028] The diaper 1 is a disposable diaper having a pants-like shape in its natural state. In the pants-like state shown in FIG. 1 , the diaper 1 has a vertical, horizontal, and front-to-rear direction that intersect with one another, and includes a waist opening BH and a pair of leg openings LH, LH. The upper side in the vertical direction corresponds to the waist opening BH side, and the lower side corresponds to the crotch side. Here, the "natural state" refers to the state of the diaper 1 after it has been left for a predetermined period of time. For example, the waist member 20 of the diaper 1 is stretched outward in both the horizontal directions to create a "stretched state." This stretched state is maintained for 15 seconds, and then the tension on the diaper 1 is released and the diaper 1 is placed on a flat surface such as a desk. The natural state is the state of the diaper 1 after it has been left flat for 5 minutes.

[0029] In addition, in the unfolded state shown in Fig. 2, the diaper 1 has a front-rear direction and a left-right direction that intersect with each other. The front-rear direction in the unfolded state is a direction along the up-down direction and the front-rear direction in the pants-type state shown in Fig. 1, and corresponds to the longitudinal direction of the absorbent main body 10. The left-right direction in the unfolded state is the same as the left-right direction in the pants-type state shown in Fig. 1. In addition, as shown in Fig. 3, the direction in which the materials constituting the diaper 1 are layered is referred to as the thickness direction. 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.

[0030] 2 has a symmetrical shape in the front-to-rear direction, as will be described later, and there is no distinction between a front side (ventral side) and a rear side (back side). Therefore, hereinafter, instead of referring to the "front side" and "rear side" in the front-to-rear direction, the two sides will be formally referred to as "one side" and "the other side" in the front-to-rear direction.

[0031] The diaper 1 comprises a liquid-absorbent main body 10 that absorbs body waste and a waistband member 20 that is disposed on the non-skin side of the absorbent main body 10. The waistband member 20 is an exterior member that constitutes the exterior of the diaper 1, and comprises a first waistband member 30 that corresponds to one side of the body in the front-to-back direction of the diaper 1, and a second waistband member 40 that corresponds to the other side of the body in the front-to-back direction of the diaper 1. That is, the diaper 1 of this embodiment is a so-called three-piece pants-type diaper that comprises the absorbent main body 10, as a first component, that is placed in the crotch area of ​​the wearer and absorbs body waste such as urine; the first waistband member 30 that covers one side of the waist in the front-to-back direction of the wearer, as a second component; and the second waistband member 40 that covers the other side of the waist in the front-to-back direction of the wearer, as a third component.

[0032] In the unfolded state shown in Fig. 2, the one waistline member 30 and the other waistline member 40 are aligned parallel to each other with a gap in the front-to-rear direction, with the absorbent main body 10 suspended between them, and each end 10ea, 10eb in the longitudinal direction (front-to-rear direction) of the absorbent main body 10 being joined and fixed to the skin side of the nearest waistline members 30, 40, giving the absorbent main body 10 a generally H-shaped appearance in a plan view. From this state, the absorbent main body 10 is then folded in half, with the central position CL in the front-to-rear direction as the folding position. The central position CL is the central position of the absorbent main body 10 in the front-to-rear direction and also the central position of the entire diaper 1 in the front-to-rear direction.

[0033] In this folded state, the opposing one-side waistline member 30 and the other-side waistline member 40 are joined and connected to each other at the side portions 30sw and 40sw on both the left and right sides, forming a pair of side joints 50, 50. That is, the pair of side joints 50, 50 form the one-side waistline member 30 and the other-side waistline member 40 into a ring shape. The side joints 50 are formed by a known joining method such as welding or bonding. This results in a pants-type diaper 1 having a waist-opening BH and a pair of leg-openings LH, LH as shown in FIG. 1 . (Absorbent Main Body 10) FIG. 4A is a plan view of the absorbent main body 10, and FIG. 4B is a schematic cross-sectional view of the absorbent main body 10. The absorbent main body 10 includes an absorbent core 11 that absorbs excreted liquid, a top sheet 12 disposed closer to the skin in the thickness direction than the absorbent core 11, and a back sheet 13 disposed closer to the skin than the absorbent core 11. In addition, a second sheet 14 is provided between the top sheet 12 and the absorbent core 11 in the thickness direction. However, the second sheet 14 does not necessarily have to be provided.

[0034] The absorbent core 11 is a component that absorbs and retains excretions such as urine, and is formed of liquid-absorbent fibers, such as pulp fibers mixed with superabsorbent polymer (SAP). The outer periphery of the absorbent core 11 may be covered with a liquid-permeable sheet material (core wrap sheet 11b), such as tissue paper or nonwoven fabric. The absorbent core 11 of this embodiment has a constricted portion 11c, which narrows in the left-right direction, between one longitudinal end and the other longitudinal end, and has a generally hourglass shape in plan view, as shown in FIG. 4A . This constricted portion 11c is the portion that is sandwiched between the wearer's legs when the diaper 1 is worn, and the short length (narrow width) of this portion in the left-right direction allows the absorbent core 11 to fit more easily between the wearer's legs.

[0035] The top sheet 12 is a liquid-permeable sheet, and may be made of, for example, a hydrophilic air-through nonwoven fabric or a spunbond nonwoven fabric. In this embodiment, as shown in Figure 4B, both left and right sides are folded back toward the non-skin side so as to wrap around the absorbent core 11. The second sheet 14 is also made of the same material as the top sheet.

[0036] The back sheet 13 has a two-layer structure consisting of a liquid-impermeable sheet 13a and an outer sheet 13b disposed on the non-skin side. The liquid-impermeable sheet 13a is made of a liquid-impermeable and moisture-permeable sheet material. For example, a microporous breathable resin film, which is made of a resin such as polyethylene or polypropylene and has a plurality of fine holes formed therein, can be used. The liquid-impermeable sheet 13a is preferably a sheet material that has "leakproof" properties that prevent liquid from passing through, but also has "moisture permeability" and "breathability" that allow water vapor and air to pass through. On the other hand, the outer sheet 13b is made of a flexible hydrophobic nonwoven fabric. For example, an air-through nonwoven fabric or a spunbond nonwoven fabric can be used.

[0037] A pair of leakage preventing walls 15 is provided on both left-right side portions of the absorbent main body 10 along the front-rear direction (the longitudinal direction of the absorbent main body 10). In this embodiment, the leakage preventing walls 15 are formed by the above-mentioned outer sheet 13b. Specifically, in the left-right direction, a portion of the outer sheet 13b extends outward beyond both ends of the absorbent core 11 and is folded toward the skin at multiple locations as shown in FIG. 4B , thereby forming the pair of leakage preventing walls 15. A leakage preventing wall elastic member 16 such as rubber thread is attached to the skin-side end (tip) of each leakage preventing wall 15 in a stretched state along the front-rear direction (the longitudinal direction of the absorbent main body 10). When the diaper 1 is worn, the leakage preventing wall elastic member 16 exhibits stretchability, causing the leakage preventing wall 15 to rise toward the skin of the wearer and fit snugly against the wearer's crotch area.

[0038] Furthermore, leg elastic members 17 such as rubber threads are attached to both left and right sides of the absorbent body 10 in a stretched state along the front-to-back direction (the longitudinal direction of the absorbent body 10). When the diaper 1 is worn, the stretchability of the leg elastic members 17 causes both sides of the absorbent body 10 to contract, making it easier to fit around the wearer's legs (groin area).

[0039] 3, the one-side waistline member 30 has a skin-side sheet 31 disposed closest to the skin in the thickness direction, a non-skin-side sheet 32 ​​laminated adjacent to the non-skin-side of the skin-side sheet 31, and a waistline elastic member 35 provided between the skin-side sheet 31 and the non-skin-side sheet 32 ​​in the thickness direction. Note that the one-side waistline member 30 basically has a two-layer structure of the skin-side sheet 31 and the non-skin-side sheet 32, but may partially have a three-layer or more layer structure, for example, a skin-side sheet 36 described below.

[0040] The skin-side sheet 31 and the non-skin-side sheet 32 ​​are rectangular sheet members in plan view as shown in Fig. 2, and are formed of, for example, an SMS nonwoven fabric. The upper end (one end in the front-to-rear direction) of the non-skin-side sheet 32 ​​has a portion folded back from the non-skin-side to the skin-side and from one side in the front-to-rear direction to the other. This folded back portion prevents the end edges of the non-skin-side sheet 32 ​​and the skin-side sheet 31 from coming into direct contact with the wearer's skin, thereby preventing the wearer from feeling uncomfortable or stiff when putting on the diaper 1.

[0041] The waist elastic members 35 are arranged in a row at intervals in the vertical direction between the skin side sheet 31 and the non-skin side sheet 32, and are attached in a stretched state in the horizontal direction (see Figures 2 and 3). The stretchability exhibited by the waist elastic members 35 allows the one-side waist member 30 to fit the waist of the wearer.

[0042] The waist elastic members 35 can be attached using an adhesive such as a hot melt adhesive. For example, the waist elastic members 35 can be attached by continuously or intermittently applying hot melt adhesive along the waist elastic members 35, stretching the adhesive at a predetermined stretch ratio, and sandwiching the elastic members 35 between the skin side sheet 31 and the non-skin side sheet 32.

[0043] The one-side waistband member 30 may also have a skin-contact sheet 36. As shown in Fig. 3, the skin-contact sheet 36 is a sheet member arranged to cover the upper end (one side end in the front-to-rear direction) of the absorbent main body 10 from the skin side, and functions as a cover sheet. This prevents the upper edge of the absorbent main body 10 from digging into the wearer's skin when the diaper 1 is put on. The skin-contact sheet 36 is formed of a hydrophobic nonwoven fabric, such as an SMS nonwoven fabric. The skin-contact sheet 36 is not necessarily provided.

[0044] (Second-Side Waistline Member 40) The second-side waistline member 40 has the same shape and configuration as the first-side waistline member 30. That is, the second-side waistline member 40 has a skin-side sheet 41 disposed closest to the skin in the thickness direction, a non-skin-side sheet 42 laminated adjacent to the non-skin-side of the skin-side sheet 41, and a waistline elastic member 45 provided between the skin-side sheet 41 and the non-skin-side sheet 42 in the thickness direction. Also, like the first-side waistline member 30, the non-skin-side sheet 42 may have a folded-back portion, a skin-facing sheet 46, etc. (see FIG. 3). The configuration of each component is the same as that of the first-side waistline member 30, and therefore description thereof will be omitted.

[0045] <Regarding the Positional Relationship Between the One-Side Waistline Member 30 and the Other-Side Waistline Member 40> Fig. 5 is a diagram illustrating the positional relationship between the one-side waistline member 30 and the other-side waistline member 40 with respect to the absorbent main body 10. Fig. 5 is a plan view schematically illustrating the diaper 1 (see Fig. 2) in an unfolded and stretched state.

[0046] In the diaper 1 of this embodiment, in the unfolded and stretched state shown in FIG. 5 , the one waistline member 30 and the other waistline member 40 are positioned symmetrically in the front-to-rear direction. That is, the one waistline member 30 and the other waistline member 40 are arranged so that they are equidistant from the central position CL in the front-to-rear direction. Specifically, if the distance between the central position CL and the other end 30ed of the one waistline member 30 in the front-to-rear direction is F1 and the distance between the central position CL and the one end 40ed of the other waistline member 40 in the front-to-rear direction is F2, then F1 and F2 are equal (F1 = F2). Hereinafter, the sum of F1 and F2 will be referred to as the crotch distance F (= F1 + F2). The crotch distance F represents the length of the leg openings LH that contact the wearer's crotch region when the diaper 1 (see FIG. 1 ) is worn in a pants-type state.

[0047] The one waistline member 30 and the other waistline member 40 are also symmetrically positioned in the left-right direction. That is, the central positions of the absorbent body 10, the one waistline member 30, and the other waistline member 40 in the left-right direction are all arranged so as to overlap with the central position CC of the diaper 1 in the left-right direction.

[0048] The shape and dimensions of the one-side waistline member 30 are the same as the shape and dimensions of the other-side waistline member 40. That is, the widths in the front-to-rear direction of the one-side waistline member 30 and the other-side waistline member 40 are equal. Specifically, in the front-to-rear direction, the distance h1 between one end 30eu and the other end 30ed of the one-side waistline member 30 is equal to the distance h2 between one end 40eu and the other end 40ed of the other-side waistline member 40 (h1 = h2).

[0049] Similarly, the widths in the left-right direction of the one waistline member 30 and the other waistline member 40 are equal. Here, the widths of the waistline members 30, 40 in the left-right direction are the widths of the portions that function as the waistline members 20 when the diaper 1 is worn. In other words, the left-right distance between the pair of side joint portions 50, 50 that join the one waistline member 30 and the other waistline member 40 is the width of the waistline members 30, 40 in the left-right direction. Specifically, in the left-right direction, the distance W1 between the other side end 30sl of the side joint 50 (30s) provided on one side of the one-side waistband member 30 and the one side end 30sr of the side joint 50 (30s) provided on the other side is equal to the distance W2 between the other side end 40sl of the side joint 50 (40s) provided on one side of the other-side waistband member 40 and the one side end 40sr of the side joint 50 (40s) provided on the other side (W1 = W2).

[0050] As described above, the diaper 1 of this embodiment has a shape that is symmetrical in the front-to-back and left-to-right directions when in an unfolded and stretched state. The front-to-back (left-to-right) symmetry eliminates the need to distinguish between the ventral and dorsal sides, reducing the burden on the wearer of the diaper 1 and the person assisting the wearer in putting on the diaper 1 (e.g., a caregiver). In particular, the reduced burden of the putting-on action reduces the wearer's motivation to change the diaper 1 even when the diaper needs to be changed outside the home, in a small bathroom, or at night, thereby improving the wearer's quality of life (QOL).

[0051] However, because the diaper 1 is a product mass-produced in a manufacturing factory or the like, variations in the dimensions and arrangement of each component may occur due to manufacturing errors and the like. Therefore, even if there is a difference (deviation) in the corresponding dimensions and arrangement between the one waistline member 30 and the other waistline member 40, the two are considered equal as long as the difference is within 10% of the original dimensions. For example, in the diaper 1, assume that the width h1 in the front-to-back direction of the one waistline member 30 and the width h2 in the front-to-back direction of the other waistline member 40 are different, resulting in a difference of Δh (= |h1 - h2|). In this case, if both Δh / h1 × 100(%) and Δh / h2 × 100(%) are within 10%, h1 and h2 are considered equal.

[0052] Furthermore, suppose that the distance F1 in the front-to-rear direction between one waistline member 30 and the central position CL is different from the distance F2 in the front-to-rear direction between the other waistline member 40 and the central position CL, resulting in a difference of ΔF (=|F1-F2|). In this case, if both ΔF / F1×100(%) and ΔF / F2×100(%) are within 10%, F1 and F2 are treated as being equal.

[0053] In addition to being symmetrical from front to back, the diaper 1 has the one-side waistline member 30 and the other-side waistline member 40 appropriately positioned, thereby improving ease of donning and fit.

[0054] In this specification, when the dimensions and arrangement of one waistline member 30 are described, the same description also applies to the other waistline member 40 unless otherwise specified.

[0055] 5, the distance between one end 10es of the absorbent main body 10 and the other end 30sl (40sl) of the side joint portion 50 provided on one side of the one waistline member 30 (the other waistline member 40) is defined as the waistline distance G. The length along the periphery of the leg openings LH of the diaper 1 is expressed as the waistline distance G on one side in the front-to-rear direction + the crotch distance F + the waistline distance G on the other side in the front-to-rear direction (F + 2G). In the diaper 1, the crotch distance F is longer than the waistline distance G and shorter than twice the waistline distance G (2G) (G < F < 2G).

[0056] 6A and 6B are diagrams illustrating the relationship between the crotch distance F and the waist circumference distance G. FIG. 6A illustrates a case where the crotch distance F is equal to or less than the waist circumference distance G (F≦G). In the diaper 1, when F≦G, the crotch distance F is shorter at the periphery of the leg openings LH, thereby narrowing the opening area of ​​the leg openings LH, as shown in the perspective view on the right side of FIG. 6A . In such a case, when putting on the diaper 1, the wearer's legs are likely to get caught in the crotch portion of the leg openings LH when passing them from the waist circumference openings BH to the leg openings LH. In contrast, by making the crotch distance F longer than the waist circumference distance G (G<F), the periphery of the leg openings LH is less likely to be excessively short at the crotch portion, compared to the opposite case, and this makes it easier to prevent the wearer's legs from getting caught when passing them through the leg openings LH.

[0057] FIG. 6B illustrates a case where the crotch distance F is equal to or greater than twice the waist circumference distance G (2G≦F). In the diaper 1, when 2G≦F, the opening area of ​​the leg openings LH can be sufficiently wide. However, as shown in the perspective view on the right side of FIG. 6B , the distance from the crotch to the lower end of the waist circumference member 20 tends to be excessively wide. In such a case, when the diaper 1 is worn, the waist circumference member 20 may not adequately cover the wearer's waist. In particular, the buttocks may easily protrude from the waist circumference member 20 on the back side of the wearer, which may result in a poor fit of the diaper 1 or cause discomfort to the wearer. In contrast, by making the crotch distance F shorter than twice the waist circumference distance G (F<2G), the distance from the crotch to the lower end of the waist circumference member is less likely to be excessively wide, compared to the opposite case, and the wearer's buttocks are less likely to protrude from the waist circumference member on the back side of the wearer.

[0058] Therefore, in a three-piece diaper that is symmetrical from front to back and is unlikely to be put on incorrectly, the wearer's legs can be easily put through the leg openings LH when putting on the diaper, and the wearer's buttocks are less likely to protrude from the openings, thereby improving the ease of putting on and the fit of the diaper 1 as a whole.

[0059] Furthermore, in the diaper 1, the width h1 (h2) in the front-to-rear direction of the one waistline member 30 (the other waistline member 40) is shorter than the waistline distance G (h1<G). As described above, when putting on the diaper 1, the wearer passes their legs through the upper waistline opening BH and outward through the waistline opening LH. In this case, the longer the width h1 in the front-to-rear direction of the one waistline member 30, the longer the distance the wearer's legs must pass through, increasing the likelihood that the wearer's legs will get caught in the waistline member 20 (30, 40) along the way. On the other hand, if the width h1 of the one waistline member 30 is shorter than the waistline distance G (h1<G), the likelihood that the wearer's legs will get caught in the waistline member 20 (30, 40) during the donning process is lower than in the opposite case, making it easier to put on the diaper 1 and improving donning comfort.

[0060] 5 , the distance b between one side end 30eu of the one waistline member 30 and one side end 10eu of the absorbent main body 10 is shorter than the distance c between one side end 10eu of the absorbent main body 10 and the other side end 30ed of the one waistline member 30 (b<c). The portion of the one waistline member 30 of the diaper 1 that does not overlap with the absorbent main body 10 in the front-to-rear direction (the portion represented by the distance b) has lower rigidity than the portion that overlaps with the absorbent main body 10 (the portion represented by the distance c). Therefore, in the natural state of the diaper 1, the portion of the one waistline member 30 represented by the distance b is likely to contract in the left-right direction based on the contractile force exerted by the waistline elastic members 35. Therefore, when putting on the diaper 1, it is necessary to pull the portion of the one waistline member 30 represented by the distance b in the left-right direction to greatly widen the waistline opening LH.

[0061] Therefore, if distance b were equal to or greater than distance c (c≦b), the area of ​​the easily contractible portion of the one waistline member 30 (the portion represented by distance b) would be relatively large, and a greater force would be required to widen the waist-opening LH. In contrast, in the diaper 1, distance b is shorter than distance c (b<c), and therefore the area of ​​the easily contractible portion of the one waistline member 30 (the other waistline member 40) would be relatively small, and a smaller force would be required to widen the waist-opening LH, compared to the opposite case. This improves the fit of the diaper 1.

[0062] Furthermore, in the front-to-rear direction of Fig. 5, the distance b between one side end 30eu of the one-side waistline member 30 and one side end 10eu of the absorbent main body 10 is preferably longer than the distance d between one side end 11eu of the absorbent core 11 and the other side end 30ed of the one-side waistline member 30 (d<b). The portion of the one-side waistline member 30 of the diaper 1 that overlaps with the absorbent core 11 in the front-to-rear direction (the portion represented by the distance d) is more rigid and less likely to deform than other regions of the one-side waistline member 30. In other words, the longer the distance d, the larger the area of ​​overlap between the absorbent core 11 and the one-side waistline member 30 in the thickness direction, making the one-side waistline member 30 less likely to deform. Therefore, by making the distance d shorter than the distance b (d<b) in the one-side waistline member 30, the overlapping area with the absorbent core 11 is smaller than in the reverse case, making the one-side waistline member 30 more easily deformable. This makes it easier for the one-side waistline member 30 (the other-side waistline member 40) to deform three-dimensionally to conform to the contours of the wearer's body (waistline) when the diaper 1 is put on, thereby improving fit.

[0063] In the diaper 1, the one-side waistline member 30 (the other-side waistline member 40) has a rectangular shape. That is, one edge (upper edge) and the other edge (lower edge) of the one-side waistline member 30 in the front-to-rear direction are each straight and parallel to each other. FIG. 7 illustrates a case in which the one-side waistline member 30 and the other-side waistline member 40 of the diaper 1 are substantially trapezoidal. In FIG. 7, the one-side waistline member 30 (40) has a protruding portion 38 (48) that protrudes in a substantially trapezoidal shape toward the other side (the lower side in the pants-type state) beyond the other end (lower end) 50d of the side joint portion 50 in the front-to-rear direction. In conventional diapers, a portion corresponding to the protruding portion 48 has been provided at the lower end of the back waistline member to make it easier to cover the wearer's buttocks. However, in this embodiment, if such a protrusion 38 is provided on the other side in the front-to-back direction of the one-side waistband member 30 (the lower side when in the pants-type state), when the wearer tries to move their legs while wearing the diaper 1, the protrusion 38 is likely to interfere with the movement of the legs.

[0064] In contrast, in the diaper 1 of this embodiment, the one-side waistline member 30 (the other-side waistline member 40) is rectangular (see Fig. 2, etc.), and is not provided with the protruding portion 38 (48) as shown in Fig. 7. This allows the wearer to move their legs freely even while wearing the diaper 1, and reduces the likelihood of problems such as the protruding portion 38 (48) interfering with the movement of moving the legs back and forth while walking.

[0065] 8 is an enlarged view of a portion of the one-side waistline member 30 and the absorbent main body 10 in the unfolded and stretched state of the diaper 1. The one-side waistline member 30 is provided with a plurality of waistline elastic members 35 that stretch in the left-right direction and are spaced apart in the front-rear direction. Of these plurality of waistline elastic members 35, 35, the waistline elastic member 35 located furthest to the other side in the front-rear direction (the lowest side in the pants-type state) is referred to as the lower end elastic member 35b.

[0066] In the region where at least one side waistline member 30 and the absorbent main body 10 overlap in the front-to-back direction of Figure 8, the distance G35b between the other end 30ed of the one side waistline member 30 and the lower end elastic member 35b is greater than the maximum value of the spacing (pitch) P35 in the front-to-back direction of the waistline elastic member 35 (G35b > P35).

[0067] By arranging the plurality of waist elastic members 35, 35 at a predetermined pitch (P35) in the region where the absorbent main body 10 and the one-side waistline member 30 overlap in the front-rear direction, a uniform contractile force can be applied to the lower edge of the one-side waistline member 30 (i.e., the portion along the periphery of the leg openings LH) in the left-right direction. This allows the leg openings LH to easily fit around the wearer's groin when the diaper 1 is worn. Meanwhile, by making the distance G35b between the lower end elastic member 35b and the other end (lower end) 30ed of the one-side waistline member 30 in the front-rear direction wider than the maximum value of the pitch P35 of the waist elastic members 35, a predetermined distance can be easily ensured between the periphery of the leg openings LH (the lower end 30ed of the one-side waistline member 30) and the lower end elastic member 35b. Therefore, when the wearer puts on the diaper 1 and passes the legs through the leg openings LH, the wearer's toes and other parts of the legs are less likely to get caught on the periphery (lower end 30ed) of the leg openings LH, making it easier to pass the legs through the leg openings LH.

[0068] Furthermore, when viewed in the thickness direction, the constricted portion 11c of the absorbent core 11 overlaps with the one-side waistline member 30 (the other-side waistline member 40). The portion of the one-side waistline member 30 overlapping with the constricted portion 11c is less susceptible to the influence of the rigidity of the absorbent core 11 in the shaded area in FIG. 8 . That is, compared to when the absorbent core 11 does not have the constricted portion 11c, the overlapping area between the absorbent core 11 and the one-side waistline member 30 is smaller, and deformation of the one-side waistline member 30 is less likely to be hindered by the highly rigid absorbent core 11. Therefore, when putting on the diaper 1, the one-side waistline member 30 can freely deform to accommodate the contours of the wearer's body, providing a more comfortable fit. Furthermore, since the shaded area in FIG. 8 is close to the periphery of the leg openings LH, the one-side waistline member 30 is more easily deformed in this area, making it easier to put the wearer's legs through the leg openings LH.

[0069] 9A to 9C are diagrams illustrating the joining of the one-side waistline member 30 (the other-side waistline member 40) and the absorbent main body 10. As described above, in the diaper 1, the one-side waistline member 30 (the other-side waistline member 40) is joined to the non-skin side in the thickness direction of the absorbent main body 10. The joining of the absorbent main body 10 and the one-side waistline member 30 (40) is performed via a main body joint 60 formed with an adhesive such as a hot melt adhesive. In this embodiment, the main body joint 60 has a first main body joint 61 formed on the skin side of the one-side waistline member 30, and a second main body joint 62 formed on the non-skin side of the absorbent main body 10.

[0070] For example, during the manufacturing process of the diaper 1, adhesive is applied to a predetermined region (the region indicated by diagonal lines in Fig. 9A ) on the skin side of the one waistline member 30 to form the first main body joint 61. Although a detailed description will be omitted, during the manufacturing process of the diaper 1, the one waistline member 30 is manufactured while being transported in the left-right direction in Fig. 9A , and therefore the adhesive that forms the first main body joint 61 is also applied in the left-right direction.

[0071] Furthermore, in the manufacturing process of the diaper 1, adhesive is applied to a predetermined region (the region indicated by diagonal lines in Fig. 9B) on the non-skin side of the absorbent main body 10 to form the second main body joint 62. In the manufacturing process of the diaper 1, the absorbent main body 10 is manufactured while being transported in the front-to-rear direction in Fig. 9B, and the adhesive that forms the second main body joint 62 is also applied in the front-to-rear direction.

[0072] In this state, as shown in Figure 9C , the one-side waistline member 30 and the absorbent main body 10 are joined in the thickness direction so that the first main body joint 61 and the second main body joint 62 overlap. At this time, the areas (shape and size) where the adhesive is applied differ between the first main body joint 61 and the second main body joint 62, resulting in the formation of portions with large and small basis weights in the main body joint 60. For example, in Figure 9C , the portion of the main body joint 60 where the first main body joint 61 and the second main body joint 62 overlap in the left-right center is designated as the central joint 60c, and the portions located on both sides of the central joint 60c in the left-right direction are designated as the side joints 60s. In this case, the basis weight of the adhesive in the side joints 60s is equal to the basis weight of the second main body joint 62 alone, and the basis weight of the adhesive in the central joint 60c is equal to the combined basis weight of the first main body joint 61 and the second main body joint 62. That is, the basis weight of the central joint portion 60c is greater than the basis weight of the both side joint portions 60s.

[0073] The boundary WB60 between the central joint 60c and the side joints 60s is prone to become a starting point for bending deformation of the one-side waistline member 30 and the absorbent main body 10, due to a difference in basis weight of the adhesive. In the diaper 1, as shown in Fig. 9C, the boundary WB60 is located outboard of the absorbent core 11 in the left-right direction. Because it does not overlap with the highly rigid absorbent core 11, bending deformation of the one-side waistline member 30 and the like is more likely to occur at the boundary WB60, allowing the diaper 1 to better fit the contours of the wearer's body.

[0074] ===Other Embodiments= ...

[0075] DESCRIPTION OF SYMBOLS 1 diaper (absorbent article), 10 absorbent body, 11 absorbent core, 11b core wrap sheet, 11c constricted portion, 12 top sheet, 13 back sheet, 13a liquid-impermeable sheet, 13b outer sheet, 14 second sheet, 15 leakage-preventing wall portion, 16 leakage-preventing wall elastic member, 17 leg-hole elastic member, 20 waist member, 30 one-side waist member, 31 skin-side sheet, 32 non-skin-side sheet, 35 waist-hole elastic member, 35b lower end elastic member, 36 skin-side sheet, 38 protruding portion, 40 other-side waist member, 41 skin-side sheet, 42 non-skin-side sheet, 45 waist-hole elastic member, 46 skin-side sheet, 48 protruding portion, 50 side joint portion, 60 main body joint portion, 60c Central joint, 60s: both side joints, 61: first main body joint, 62: second main body joint, BH: waist opening, LH: leg opening, CL: central position (front-to-back direction), CC: central position (left-to-right direction), F: crotch distance, F1: distance (one side), F2: distance (other side), G: waist distance

Claims

1. An absorbent article having a front-to-rear direction and a left-to-right direction which intersect each other in an unfolded state, comprising: an absorbent main body; a one-side waistline member arranged on one side of the absorbent main body in the front-to-rear direction; and a other-side waistline member arranged on the other side of the absorbent main body in the front-to-rear direction, and a pair of side joints joining both sides in the left-to-right direction of the one-side waistline member and the other-side waistline member, wherein in an unfolded and extended state, the absorbent article has a shape which is symmetrical in the front-to-rear direction, and wherein, when the distance between the other end of the one-side waistline member and one end of the other-side waistline member in the front-to-rear direction is defined as the crotch distance, and when the distance between the one end of the absorbent main body and the other end of the side joint provided on one side of the one-side waistline member or the other-side waistline member in the left-to-right direction is defined as the waistline distance, the crotch distance is longer than the waistline distance and shorter than twice the waistline distance.

2. An absorbent article according to claim 1, characterized in that in an unfolded and stretched state, the width of the one side waistline member and the other side waistline member in the front-to-rear direction is shorter than the waistline distance.

3. An absorbent article as claimed in claim 1 or 2, characterized in that in an unfolded and stretched state, in the front-to-rear direction, the distance between one end of said one side waistline member and one end of said absorbent main body is shorter than the distance between one end of said absorbent main body and the other end of said one side waistline member.

4. An absorbent article as described in claim 3, characterized in that the absorbent main body has an absorbent core, and in an unfolded and stretched state, in the front-to-rear direction, the distance between one end of the one side waistline member and one end of the absorbent main body is longer than the distance between one end of the absorbent core and the other end of the one side waistline member.

5. An absorbent article according to claim 1 or 2, characterized in that the one side waistline member and the other side waistline member are rectangular.

6. An absorbent article as described in claim 1 or 2, characterized in that the one-side waistline member and the other-side waistline member are provided with a plurality of waistline stretch members spaced apart in the front-to-rear direction, which stretch in the left-right direction, and in an unfolded and extended state, in the area where the one-side waistline member and the absorbent main body overlap in the front-to-rear direction, the distance between the waistline stretch member located on the other side of the one-side waistline member and the other end of the one-side waistline member is greater than the maximum value of the pitch between two adjacent waistline stretch members.

7. An absorbent article as described in claim 1 or 2, characterized in that the absorbent main body has an absorbent core, the absorbent core has a constricted portion between one end and the other end in the front-to-rear direction, the constricted portion having a narrower width in the left-to-right direction, and when viewed in the thickness direction in an unfolded and stretched state, the absorbent article has portions that overlap with each of the one side waistline member and the other side waistline member.

8. An absorbent article as described in claim 1 or 2, characterized in that the absorbent main body has an absorbent core, and has main body joints that join the absorbent main body to each of the one side waistline member and the other side waistline member with an adhesive, the main body joints have a central joint located in the center in the left-right direction and both side joints located on either side of the central joint in the left-right direction, the basis weight of the adhesive at the central joint is greater than the basis weight of the adhesive at the both side joints, and the boundary between the central joint and the both side joints is located outside the absorbent core in the left-right direction.

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