absorbent articles

Abstract

To provide an absorbent article in which fastening tape can be attached more easily than before. [Solution] A diaper 1, which is an absorbent article, comprises an absorbent main body 3 including an absorber 33, and a pair of fastening tapes 6, 6 extending outward in the lateral direction Y from the side portions of the back-side portion B in the lateral direction Y. The back-side portion B has an elastic member arrangement region R in which a back-side elastic member 51 extending in the lateral direction Y is arranged. When the diaper 1 is viewed in plan, the elastic member arrangement region R has a different lateral length on one side and the other side of a longitudinal centerline CLx of the diaper 1, which bisects the length of the diaper 1 in the lateral direction Y. When a back-side elastic region R3 is defined as a strip-shaped region in the back-side portion B that overlaps the elastic member arrangement region R in the longitudinal direction X and extends the entire length of the diaper 1 in the lateral direction Y, the elasticity of the back-side elastic region R3 in the lateral direction Y differs on the one side and the other side.

Description

[Technical Field]

[0001] The present invention relates to absorbent articles. [Background technology]

[0002] Generally, flat-type diapers are provided with a fastening means for integrating the ventral and dorsal sections. Conventionally, this fastening means has been a fastening tape, which allows for a mechanical connection that can be easily attached and removed. More specifically, flat-type diapers have a ventral section that faces the wearer's ventral side, a dorsal section that faces the wearer's ventral side, and a crotch section located therebetween. When worn, the wearer stretches both side edges of the dorsal section toward the wearer's ventral side, and fastening tape attachment portions provided on the both side edges are fastened to the outer surface of the ventral section. This allows the diaper to be adequately fastened around the waist and prevent it from slipping down. Fastening tapes typically have a tape substrate, which constitutes the main body of the fastening tape, to which attachment portions made of hook material or the like are attached. In flat-type diapers, a portion of the tape substrate is fixed to the flap portion of the diaper, and the remaining portion of the tape substrate is attached so as to extend beyond the flap portion. As such an open-type diaper, for example, the open-type diaper described in Patent Document 1 has been proposed.

[0003] Patent Document 1 describes an open-type diaper comprising a first sheet, a second sheet, an absorbent body disposed between the first and second sheets, and fastening tapes provided on both sides of the back portion. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2019-115402 Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, infants, who are the primary wearers of flat-type diapers, need their diapers changed very frequently, and therefore it is preferable that the diaper be easy to put on and take off on infants who are the wearers. However, with the flat-type diaper described in Patent Document 1, the fastening tape may not be fastened smoothly due to the baby's movements, making it difficult to put on the diaper.

[0006] Therefore, an object of the present invention is to provide an absorbent article in which the fastening tape can be attached more easily than before. [Means for solving the problem]

[0007] The present invention relates to an absorbent article having a vertical direction extending from the wearer's abdomen through the crotch area to the back side and a horizontal direction perpendicular to the vertical direction, and having a crotch area that is located in the crotch area when worn, a ventral side area that is located closer to the wearer's abdomen than the crotch area, and a back side area that is located closer to the wearer's back than the crotch area. In one embodiment, the absorbent article preferably comprises an absorbent main body including an absorbent body, and a pair of fastening tapes extending outward in the lateral direction from the lateral side portions of the back side portion. In one embodiment, the back portion preferably has an elastic member arrangement region in which a back-side elastic member extending in the transverse direction is arranged. In one embodiment, when the absorbent article is viewed in a plane, it is preferable that the stretch member arrangement area has different horizontal lengths on one side and the other side of the vertical center line of the absorbent article, which divides the length of the absorbent article in half in the horizontal direction. In one embodiment, when a band-shaped region in the back portion that overlaps with the stretchable member arrangement region in the vertical direction and extends over the entire length of the absorbent body in the horizontal direction is defined as the back stretchable region, it is preferable that the stretch rate in the horizontal direction of the back stretchable region is different between the one side and the other side. [Effects of the Invention]

[0008] According to the present invention, an absorbent article is provided in which the fastening tape can be easily attached. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic plan view of the skin-facing side of an unfolded disposable diaper, which is one embodiment of an absorbent article according to the present invention, in an unfolded and stretched state. [Figure 2] FIG. 2 is a cross-sectional view taken along line II in FIG. [Figure 3] FIG. 3 is a cross-sectional view taken along line II-II in FIG. [Figure 4] FIG. 4 is an enlarged plan view of the back side portion shown in FIG. [Figure 5] FIG. 5 is a partially enlarged plan view of one side of FIG. [Figure 6] FIG. 6 is an explanatory diagram of the rear elastic arrangement region in the absorbent article of the present invention. [Figure 7] 7(a) to 7(c) are explanatory diagrams for explaining how to put on the diaper shown in FIG. [Figure 8] FIG. 8 is a view equivalent to FIG. 4 showing another embodiment of the absorbent article of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The present invention will be described below based on preferred embodiments with reference to the drawings. In the following description of the drawings, the same or similar parts are designated by the same or similar reference numerals. The drawings are basically schematic, and the ratios of the dimensions may differ from those of the actual product.

[0011] The absorbent article of the present invention will be described below based on its preferred embodiments. Figures 1 to 7 show an open-type disposable diaper (hereinafter simply referred to as "diaper"), which is one embodiment of the absorbent article of the present invention. The diaper 1 shown in FIG. 1 has a ventral portion A that is positioned on the ventral side of the wearer when worn, a dorsal portion B that is positioned on the dorsal side, and a crotch portion C that is positioned in the crotch area. The diaper 1 also has a longitudinal direction X that extends from the ventral portion A through the crotch portion C to the dorsal portion B, and a transverse direction Y that is perpendicular to the longitudinal direction X. The ventral portion A, crotch portion C, and dorsal portion B extend continuously in the front-to-back direction of the wearer. The crotch portion C is constricted in the longitudinal direction X of the diaper 1 so that its length in the transverse direction Y is narrower than that of the ventral portion A and dorsal portion B, and both side edges have an inwardly convex shape. The crotch portion C also has an excretory-facing portion (not shown) that is positioned opposite the excretory portion of the wearer when the diaper 1 is worn.

[0012] The diaper 1 is a so-called flat-type diaper, and comprises an absorbent main body 3 including an absorber 33, an exterior sheet 10 arranged on the non-skin-facing side of the absorbent main body 3, and a pair of fastening tapes 6, 6 fixed to both side edges (side flap portions SF) along the longitudinal direction X of the absorber 33 in the back portion B. The absorbent main body 3 and the exterior sheet 10 are joined by a known joining means such as an adhesive. The diaper 1 is fitted to a wearer by fastening the fastening portion 62 of the fastening tape 6 to the fastening region 9 of the outer sheet 10.

[0013] In this embodiment, the longitudinal centerline CLx is an imaginary straight line extending in the longitudinal direction X, dividing the diaper 1 in the unfolded and stretched state into two equal parts in the lateral direction Y. The lateral centerline CLy is an imaginary straight line extending in the lateral direction Y, dividing the diaper 1 in the unfolded and stretched state into two equal parts in the longitudinal direction X.

[0014] In this specification, the term "unfolded and stretched state" refers to a state in which the absorbent article is unfolded and the elastic members of the absorbent article are stretched so that the dimensions of the members other than the elastic members in a plan view are the design dimensions, i.e., until the influence of the elastic members is completely eliminated. In this specification, unless otherwise specified, the dimensions of each part of the diaper 1, such as the length in the longitudinal direction X or the lateral direction Y, refer to the dimensions (design dimensions) when the elastic members of each part are stretched and each member is stretched.

[0015] In this embodiment, as shown in Fig. 1, the longitudinal direction of the absorbent main body 3 coincides with the longitudinal direction X in a plan view in an unfolded and stretched state. The absorbent main body 3 is a main component of the diaper 1, and includes, in addition to the absorbent body 33, a topsheet 31 arranged on the skin-facing side of the absorbent body 33, and a backsheet 32 ​​arranged on the non-skin-facing side of the absorbent body 33. Both sheets 31, 32 extend outward in the longitudinal direction X from both ends of the absorbent body 33 in the longitudinal direction X, and also extend outward in the transverse direction Y from both side edges of the absorbent body 33 along the longitudinal direction X. The constituent components of the absorbent main body 3 are joined to each other by a known joining means such as an adhesive.

[0016] In this specification, when focusing on an absorbent article or a component thereof (e.g., an absorbent body), the "skin-facing side" refers to the side that faces the wearer's skin when the absorbent article is worn, and the "non-skin-facing side" refers to the side that faces away from the wearer's skin when the absorbent article is worn. In other words, the skin-facing side is the outer surface that is relatively close to the wearer's skin, and the non-skin-facing side is the outer surface that is relatively far from the wearer's skin. Furthermore, "when worn" and "in a worn state" refer to a state in which the absorbent article is worn while maintaining the correct wearing position.

[0017] As shown in Figure 1, the absorbent body 33 is arranged so that its longitudinal direction coincides with the longitudinal direction X of the diaper, and extends from the ventral portion A through the crotch portion C to the dorsal portion B. The absorbent body 33 is formed by covering an absorbent core 331 having absorbent properties with a liquid-permeable core wrap sheet (not shown). It is preferable that at least the skin-facing surface of the absorbent core 331 is covered with the core wrap sheet, and the entire surface, including the skin-facing surface and the non-skin-facing surface, may be covered with the core wrap sheet. The absorbent body 33 may also be composed of only the absorbent core 331 without including the core wrap sheet.

[0018] In this embodiment, the diaper 1 includes a pair of leakage-preventing cuffs 7, 7 extending in the longitudinal direction X and arranged to cover both side edges of the topsheet 31 along the longitudinal direction X. Each leakage-preventing cuff 7 includes a liquid-impermeable and breathable cuff-forming sheet 71, one end of which in the lateral direction Y is fixed to another member as a fixed end, and the other end of which in the lateral direction Y is a free end not fixed to another member. A leakage-preventing cuff-forming elastic member 72 is arranged at the free end of the cuff-forming sheet 71 and is fixed in a stretched state in the longitudinal direction X, allowing it to stretch in the same direction. When the diaper 1 is worn, the contractile force of the leak-proof cuff-forming elastic member 72 causes the free end of the cuff-forming sheet 71 to stand up toward the wearer, at least in the crotch region C, with the fixed end serving as the standing base, thereby causing a pair of leak-proof cuffs 7, 7 to stand up, thereby preventing excrement such as urine from flowing outward in the lateral direction Y.

[0019] In this embodiment, the diaper 1 includes flap portions located outward from the periphery of the absorbent body 33. The flap portions are composed of components arranged around the periphery of the absorbent body 33, and in this embodiment, include an outer sheet 10, a top sheet 31, a back sheet 32, and a cuff-forming sheet 71. As shown in FIG. 1 , the flap portions on the ventral region A of the diaper 1 include the sheets 10, 31, 32, and 71, as well as a ventral stretchable sheet 40. On the back region B of the diaper 1, the flap portions include the sheets 10, 31, 32, and 71, as well as a back stretchable sheet 50. The ventral stretchable sheet 40 and the back stretchable sheet 50 are employed for reinforcing the diaper 1, preventing leakage, and providing a mounting point for the stretchable members, respectively. The ventral stretchable sheet 40 and the back stretchable sheet 50 are hydrophobic and can be made of materials that can be used for the back sheet 32. The plurality of members constituting the flap portion are joined together by known joining means such as adhesive, heat sealing, ultrasonic sealing, etc. The abdominal-side stretchable sheet 40 may be omitted. The side flap portions SF are the portions of the flap portions that are located outward in the transverse direction Y from both side edge portions 3S, 3S of the absorbent body 33 and from imaginary extension lines of each side edge portion 3S. The side flap portions SF extend over the entire length of the diaper 1 in the longitudinal direction X. In this embodiment, as shown in FIG. 1, the side flap portion SF has a constricted portion in the central region in the longitudinal direction X (the region located in the crotch portion C). The constricted portion is the portion of the diaper 1 that is arranged around the legs of the wearer (leg surrounding portion), and the elastic member 4 for the leg gathers is arranged in the longitudinal direction X.

[0020] As shown in Fig. 1, a pair of side flap portions SF, SF are provided with a plurality of leg gather elastic members 4. The leg gather elastic members 4 are arranged in a stretched state along the longitudinal direction X at positions outward in the transverse direction Y from the side edges of the absorbent body 33. The leg gather elastic members 4 extend over at least the entire length of the crotch portion C in the longitudinal direction X. Contraction of the elastic members 4 forms leg gathers in the left and right portions that are disposed around the legs of the wearer, i.e., on both sides of the diaper 1 in the longitudinal direction X. In this embodiment, two elastic members 4 for leg gathers are arranged in each of a pair of side flap portions SF, SF, but the number of elastic members 4 for leg gathers arranged in the side flap portion SF is not particularly limited and may be one or three or more.

[0021] As shown in FIG. 1, the diaper 1 includes a pair of fastening tapes 6, 6 extending outward in the transverse direction Y from the sides of the back-side portion B. As shown in FIG. 1, the fastening tape 6 includes a tape substrate 61 and a fastening portion 62 fixed to the tape substrate 61. The material of the tape substrate 61 is not particularly limited, and examples thereof include nonwoven fabric, resin film, and a laminate of nonwoven fabric and resin film. One end of the fastening tape 6 in the longitudinal direction (transverse direction Y) is fixed to both side edges 1S, 1S of the back-side portion B of the diaper 1 along the longitudinal direction X by known means such as adhesive or fusion bonding. In the illustrated embodiment, the fastening tape 6 is fixed between the cuff-forming sheet 71 and the back-side stretchable sheet 50 (see FIG. 2). However, the fastening tape 6 may be fixed to the non-skin-facing surface of the outer sheet 10 or to the skin-facing surface of the cuff-forming sheet 71.

[0022] The fastening portion 62 is fixed to the skin-facing surface of the tape substrate 61 at the extension from the side edge portion 1S along the longitudinal direction X in the back-side portion B. The fastening portion 62 is removably fastened to the fastening region 9 (see FIG. 1 ) provided on the non-skin-facing surface of the outer sheet 10 in the ventral portion A. In the present invention, the fastening structure including the fastening portion 62 and the fastening region 9 is not particularly limited, and any fastening structure in this type of flat-type diaper can be used without particular limitation. An example of the fastening structure is a mechanical hook-and-loop fastener. The term "mechanical hook-and-loop fastener" as used herein refers to a fastener that is a combination of a surface member (male member) on one side of which a hook material (engaging member) consisting of hook-shaped protrusions is arranged, and a surface member (female member) on one side of which a loop material consisting of pile-shaped protrusions is arranged. A specific example of a mechanical hook-and-loop fastener is Magic Tape (registered trademark). Typically, the fastening portion 62 is the male member and the fastening region 9 is the female member, but this may be reversed.

[0023] The diaper 1 has a back-side elastic member for forming waist gathers arranged in the back portion B. The back-side elastic member is preferably arranged to extend between a pair of side edges 1S, 1S in the lateral direction Y. The back-side elastic member may be a strip-like or thread-like elastic member, or a stretchable sheet. In the diaper 1 of this embodiment, the back-side stretchable members are elastic members. More specifically, a back-side stretchable sheet 50 for forming waist gathers is disposed in the back portion B, and a plurality of back-side elastic members 51 extending in the lateral direction Y of the diaper 1 are sandwiched and fixed in a stretched state between two sheet members 50a, 50b (see FIGS. 2 and 3). The plurality of back-side elastic members 51 are disposed intermittently in the longitudinal direction X, thereby enabling the back-side stretchable sheet 50 to stretch in the lateral direction Y. It is preferable to use a thread-like elastic member such as rubber thread as the back-side elastic member 51. In the diaper 1 of this embodiment, a back stretch sheet 50 is arranged between the top sheet 31 and the back sheet 32, and the back stretch sheet 50 is joined to the top sheet 31 and the back sheet 32, but instead of the back stretch sheet 50, multiple elastic members may be formed by being sandwiched and fixed in a stretched state between the top sheet 31 and the back sheet 32.

[0024] 4, the diaper 1 has an elastic member arrangement region R in the back portion B where the back-side elastic members 51 are arranged. In this embodiment, the elastic member arrangement region R is an area surrounded by an imaginary line RS connecting the ends of the back-side elastic members 51 adjacent in the longitudinal direction X on both sides of the transverse direction Y, and by the back-side elastic members 51a and 51b, which are located outermost and innermost in the longitudinal direction X, among the multiple back-side elastic members 51. The elastic member arrangement region R includes the back-side elastic members 51a and 51b.

[0025] In the present invention, as shown in Fig. 4, the rear elasticized region R3 is defined as a strip-shaped region of the rear portion B of the diaper 1 that overlaps the elasticized member region R in the longitudinal direction X and extends over the entire length of the diaper 1 in the transverse direction Y. The rear elasticized region R3 is a region of the rear portion B sandwiched between the outermost rear elastic member 51a and the innermost rear elastic member 51b in the longitudinal direction X. The rear elasticized region R3 includes the rear elastic member 51a and the rear elastic member 51b. 1 and 4, the ends of all the back-side elastic members 51 in the horizontal direction Y are positioned at the same position when viewed along the vertical direction X. However, as shown in Fig. 6, if the ends of all the back-side elastic members 51 in the horizontal direction Y are not positioned at the same position when viewed along the vertical direction X, that is, if the back-side elastic members 51 include back-side elastic members whose lengths in the horizontal direction Y are the same on one side and back-side elastic members whose lengths in the horizontal direction Y are different on the other side of the vertical centerline CLx, the stretchable member arrangement region R is set based on the back-side elastic members 51 whose lengths in the horizontal direction Y are different on the one side and the other side. Furthermore, the back-side stretchable region R3 is set based on the back-side elastic member 51a located at the outermost position in the vertical direction X and the back-side elastic member 51b located at the innermost position in the vertical direction X.

[0026] 1 and 4, the elastic member arrangement region R has different lengths in the horizontal direction Y on one side and the other side of the vertical centerline CLx. More specifically, when the region on one side of the elastic member arrangement region R is designated as a first region R1 and the region on the other side of the elastic member arrangement region R is designated as a second region R2, the length W1 of the first region R1 in the horizontal direction Y is longer than the length W2 of the second region R2 in the horizontal direction Y (see FIG. 4). In other words, the length W3 between the side edge 1S of the back-side portion B on one side and the elastic member arrangement region R (hereinafter also referred to as the "one-side displacement amount") is shorter than the length W4 between the side edge 1S of the back-side portion B on the other side and the elastic member arrangement region R (hereinafter also referred to as the "other-side displacement amount"). With this configuration, the diaper 1 of this embodiment has a different stretch rate between one side (the first region R1 side) and the other side (the second region R2 side) of the back-side stretchable region R3. More specifically, the stretch rate in the lateral direction Y on one side (the first region R1 side) of the back-side stretchable region R3 is greater than that on the other side (the second region R2 side).

[0027] FIG. 7 shows an example of a method for putting the diaper 1 of this embodiment on a wearer (for example, a parent of an infant) on a recipient (for example, an infant). When putting the diaper 1 of this embodiment on a wearer, first, the diaper 1 is laid out in an unfolded state with the topsheet 31 facing upward, and the wearer is placed face-up on the diaper 1 (see FIG. 7(a)). Next, the abdominal portion A of the diaper 1 is folded back and placed over the wearer's abdomen. The fastening tape 6 on one side (the first region R1 side) is manually pulled to stretch one side of the dorsal portion B (see FIG. 7(b)), and the fastening tape 6 is fastened to the fastening region 9. The same operation is then performed on the fastening tape 6 on the other side (the second region R2 side) to fasten the fastening tape 6 to the fastening region 9, and the diaper 1 is put on the wearer (see FIG. 7(c)).

[0028] The diaper 1 of the present invention allows for easier fastening of the fastening tapes than conventional diapers. Specifically, in conventional diapers, the elastic member-arrangement region R has the same length in the horizontal direction Y on both sides of the vertical centerline CLx. Therefore, when fastening the fastening tapes 6 to the fastening regions 9, for example, the wearer's movements can make it difficult to smoothly fasten the first fastening tape 6. In contrast, the diaper 1 of the present invention has different lengths in the horizontal direction Y on both sides of the vertical centerline CLx. Specifically, the length in the horizontal direction Y on one side (the first region R1 side) of the elastic member-arrangement region R is longer than on the other side (the second region R2 side). As a result, the stretch rate is higher on one side (the first region R1 side) of the back-side elastic region R3, allowing for some stretch, and therefore the fastening tape 6 is less likely to become fully stretched even when pulled by hand. Therefore, when fastening the fastening tape 6 to the fastening region 9, even if the wearer moves, the fastening tape 6 can deform to follow the movement and posture of the wearer. Furthermore, in the diaper 1 of the present invention, the length in the lateral direction Y of the other side (second region R2 side) of the elastic member arrangement region R is shorter than that of the one side (first region R1 side). As a result, after fastening the fastening tape 6 located on one side (first region R1), when fastening the fastening tape 6 located on the other side (second region R2) to the fastening region 9, the other side (second region R2) of the back elastic region R3 has less stretch, so that the fastening can be done in approximately the same place without any confusion about where to fasten. As a result, it is possible to provide a smooth wearing experience.

[0029] The diaper 1 of the present invention may be fastened starting from the fastening tape 6 located on the other side (the second region R2) instead of the fastening tape 6 located on one side (the first region R1). In the back stretchable region R3, the stretch rate on the other side (the second region R2) is smaller than that on the one side (the first region R1). Therefore, even when a wearer is placed on the diaper 1, the fastening tape 6 on the other side (the second region R2) is visible from the wearer's body. In other words, when a wearer is placed on the diaper 1, the fastening tape 6 on the other side (the second region R2) is less likely to be blocked by the wearer. This makes the fastening tape 6 on the other side (the second region R2) easier to grasp than the fastening tape on the one side (the first region R1), making it easier to put on the diaper even when the wearer moves.

[0030] Thus, the diaper 1 of the present invention can be easily fastened regardless of whether the fastening tape 6 is fastened on one side (first region R1) or the other side (second region R2). That is, the diaper 1 of the present invention can easily fasten the fastening tapes 6, 6. In fastening the fastening tapes of the diaper 1 of the present invention, the wearer can freely choose which side to fasten first based on their preference or familiar method.

[0031] From the viewpoint of making the fastening operation of the fastening tape 6 easier, it is preferable that the one-side displacement amount W3 and the other-side displacement amount W4 are within the following ranges. The ratio (W4 / W3) of the one-side shift amount W4 to the one-side shift amount W3 is preferably 2.0 or more, more preferably 2.4 or more, and preferably 7.4 or less, more preferably 7.0 or less, preferably 2.0 or more and 7.4 or less, more preferably 2.4 or more and 7.0 or less. The one-side deviation amount W3 is preferably 15 mm or more, more preferably 20 mm or more, and is preferably 50 mm or less, more preferably 45 mm or less, and is preferably 15 mm or more and 50 mm or less, more preferably 20 mm or more and 45 mm or less. The other side deviation amount W4 is preferably 3 mm or more, more preferably 5 mm or more, and is preferably 25 mm or less, more preferably 20 mm or less, preferably 3 mm or more and 25 mm or less, more preferably 5 mm or more and 20 mm or less.

[0032] In order to make the fastening operation of the fastening tape easier, it is preferable that the elasticity in the horizontal direction Y on one side (first region R1 side) of the back stretchable region R3 (hereinafter also referred to as the "elasticity on one side"), the elasticity in the horizontal direction Y on the other side (second region R2 side) of the back stretchable region R3 (hereinafter also referred to as the "elasticity on the other side"), and the ratio of the elasticity on one side to the elasticity on the other side are within the following ranges. The stretch rate on one side is preferably 140.0% or more and 250.0% or less, and more preferably 150.0% or more and 230.0% or less. The stretch rate on the other side is preferably 100.0% or more and 160.0% or less, and more preferably 105.0% or more and 155.0% or less. The ratio of the stretch rate of one side to the stretch rate of the other side is preferably 1.05 or more and 2.00 or less, and more preferably 1.07 or more and 1.80 or less. The stretch ratios on one side and the other side are measured by the following method.

[0033] <Method for measuring the expansion and contraction rate on one side and the other side> With the diaper 1 unfolded and stretched, a mark is made with an oil-based pen at the position that divides the length of the diaper 1 in half (the vertical center line CLx), and the length La between the vertical center line CLx and the side edge 1S in the back portion B is measured. Next, the diaper 1 is placed in its natural state, and the length Lb between the longitudinal centerline CLx and the side edge 1S of the back portion B is measured. This measurement is performed on one side and the other side of each of the three diapers 1, and the stretch rate (%) is calculated from the arithmetic mean value of the values ​​calculated using the formula "(La / Lb) x 100." In this specification, the "natural state" refers to a state in which no external forces other than gravity are acting.

[0034] In order to ensure the above-mentioned stretchability, the fineness of the back-side elastic members 51 is preferably 155 dtex or more and 940 dtex or less, and more preferably 310 dtex or more and 700 dtex or less. The fineness of the back elastic member 51 can be measured by the following method.

[0035] <Method for measuring fineness> The entire diaper 1 is immersed in a sufficient amount of tetrahydrofuran (THF) solvent, the back elastic members 51 are peeled off from the diaper 1, and then the diaper 1 is dried in a room at 20°C and 50% humidity for one week to thoroughly dry the back elastic members 51. After drying, the length L (mm) and weight W (g) of the back elastic members 51 in their natural state are measured. The fineness (dtex) of the elastic members is calculated using the following formula: Elastic material fineness = 10,000,000 / (L x W)

[0036] Each fixing portion 63 of the fastening tape 6 is an area having a length L1 along the longitudinal direction X and a length W5 along the transverse direction Y. The fixing portions 63 are positioned at the same position when viewed along the longitudinal direction X. In other words, it is preferable that the outer edge 63a in the longitudinal direction X and the inner edge 63b in the longitudinal direction X of each fixing portion 63 are positioned at the same position when viewed along the longitudinal direction X. Here, consider a horizontally elongated region 64 extending in the horizontal direction Y that is defined between the fixing portions 63 of each of the pair of fastening tapes 6. In FIG. 4, the region 64 is the region between a two-dot chain line 65 and another two-dot chain line 66 in the longitudinal direction X, and is the region sandwiched between the two fixing portions 63 in the horizontal direction Y. The two-dot chain line 65 is a line formed by connecting the outer edges 63a of the two fixing portions 63. The two-dot chain line 66 is a line formed by connecting the inner edges 63b of the two fixing portions 63. The region 64 is the region through which the tensile force is most easily transmitted when the pair of fastening tapes 6 are pulled outward in the horizontal direction Y.

[0037] As shown in Figure 4, it is preferable that at least a portion of the elastic member arrangement region R is disposed between a pair of fastening tapes 6, 6 in the longitudinal direction X. Specifically, it is preferable that at least a portion of the back-side elastic members 51 included in the back-side stretchable sheet 50 is contained within region 64. With this configuration, when the fastening tape 6 is pulled outward in the transverse direction Y, the tensile force is efficiently transmitted to the back-side elastic members 51 included within region 64, allowing the back-side stretchable sheet 50 to easily stretch outward in the transverse direction Y. This makes it easier to fasten the fastening tape. It is preferable that the back-side elastic members 51 are elastic members located on the outer end side of the two-dot chain line 66 in the longitudinal direction X, closer to the back portion B.

[0038] As shown in Figure 4, the back-side stretched region R3 has a crotch-side stretched region R4 and a back-side stretched region R5. When the back-side stretched region R3 is divided into thirds in the longitudinal direction X, the crotch-side stretched region R4 occupies two-thirds of the crotch side, and the back-side stretched region R5 occupies the remaining region. To facilitate the fastening operation of the fastening tape, it is preferable that the stretch rates of the crotch-side stretched region R4 and the back-side stretched region R5 are different, and more specifically, it is preferable that the stretch rate of the crotch-side stretched region R4 is greater than that of the back-side stretched region R5. This configuration makes it even easier to stretch one side of the back portion B when one side of the fastening tape 6 is pulled outward in the lateral direction Y.

[0039] In order to make the fastening tape easier to fasten, it is preferable that the stretch rate in the horizontal direction Y of the stretchable region R4 closer to the crotch, the stretch rate in the horizontal direction Y of the stretchable region R5 closer to the back, and the ratio of the stretch rate in the horizontal direction Y of the stretchable region R5 closer to the crotch to the stretch rate in the horizontal direction Y of the stretchable region R4 closer to the back are within the following ranges. The stretch rate in the lateral direction Y of the crotch-side stretchable region R4 is preferably 140% or more and 250% or less, and more preferably 150% or less and 230% or less. The stretch rate in the lateral direction Y of the stretchable region R5 near the back is preferably 100% or more and 160% or less, and more preferably 105% to 155% or less. The ratio of the stretch rate in the lateral direction Y of the crotch-side stretchable region R4 to the stretch rate in the lateral direction Y of the back-side stretchable region R5 is preferably 1.20 to 1.80, more preferably 1.30 to 1.70. The stretch percentages in the lateral direction Y of the crotch-side stretchable region R4 and the back-side stretchable region R5 are measured by the following method.

[0040] <Method for measuring the stretch rate in the lateral direction Y of the stretchable region R4 near the crotch and the stretchable region R5 near the back> With the diaper 1 unfolded and stretched, a mark is made with an oil-based pen at the position that divides the length of the diaper 1 in half (the vertical center line CLx), and the length La between the vertical center line CLx and the side edge 1S of the diaper 1 is measured. Next, with the diaper 1 in its natural state, the length Lc between the longitudinal centerline CLx and the side edge 1S of the back-side portion B is measured. This measurement is performed for each region of the three diapers 1 on the side of the elastic member arrangement region R that is longer in the lateral direction Y (one side (first region R1 side) in the diaper 1 of this embodiment), and the elasticity (%) is calculated from the arithmetic mean value of the values ​​calculated by the formula "(La / Lc) x 100".

[0041] From the viewpoint of reducing leakage by improving the fit in the central region of the product, it is preferable that, in a plan view of the diaper 1, at least a portion of the crotch-side elasticized region R4 overlaps with the absorber 33 in the longitudinal direction X. Specifically, it is preferable that at least one of the back-side elastic members 51 included in the crotch-side elasticized region R4 be disposed so as to cross the absorber 33. In the diaper 1 of this embodiment, when the position of the back-side elastic member 51b, which is the innermost back-side elastic member 51 constituting the back-side elastic sheet 50 in the longitudinal direction X and disposed so as to cross the absorber 33, is compared with the position of the edge 33b of the absorber 33 on the back-side portion B side, the position of the back-side elastic member 51b is located more inward of the edge 33b of the absorber 33 in the back-side portion B of the diaper 1.

[0042] When the diaper 1 is viewed in plan, it is preferable that the end of the elastic member-arrangement region R overlaps with the fastening tape 6 on one side (the side of the first region R1). With this configuration, when the fastening tape 6 on the longer side in the lateral direction Y in the elastic member-arrangement region R is pulled outward in the lateral direction Y, it can be more easily stretched, making it easier to fasten the fastening tape. In this embodiment, as shown in Fig. 5, when the diaper 1 is viewed in plan, the outer end of the first region R1 in the elastic member-arrangement region R in the lateral direction Y overlaps with the fixing portion 63 of the fastening tape 6. As shown in Figure 5, in this embodiment, when the diaper 1 is viewed in a plane, the fixed portion 63 overlaps with the ends of all of the back elastic members 51 in the elastic member arrangement region R, but instead, the fixed portion 63 may overlap with at least one of the back elastic members 51.

[0043] It is preferable that the elastic member arrangement region R is located continuously from one side to the other in the lateral direction Y. By having the elastic member arrangement region R extend continuously from one side to the other in the lateral direction Y, the elasticity of the back portion B in the lateral direction Y is further improved, thereby further improving the fit and leak resistance of the diaper 1.

[0044] To facilitate further improvement in the fit and leakproofness of the diaper 1, the elongation stress of the elastic member-arranged region R is preferably 0.8N to 3.0N, more preferably 1.0N to 2.0N. The tensile stress is measured by the following method.

[0045] <Method for measuring stretching stress> A diaper 1 is used as a measurement sample. The two side edge portions 1S, 1S of the back portion B of the diaper 1 are fixed between a pair of chucks of a tensile tester (e.g., Shimadzu Corporation's "AGX-1kNVD"). The direction of movement of the chucks of the tensile tester is aligned with the direction of stretching, and the measurement sample is fixed so that the distance between the chucks is 20 cm. This distance between the chucks is defined as the initial distance between the chucks. The pair of chucks are then moved away from each other at a speed of 300 mm / min, and the measurement sample is pulled in the stretching direction until the distance between the chucks becomes 1.5 times the initial distance between the chucks. The tensile strength (stress) that changes with the stretching length is measured. In the above measurement, the stress when the distance between the chucks becomes 1.3 times the initial distance between the chucks is defined as the elongation stress (N).

[0046] 4, from the viewpoint of further improving the stretchability of the back portion B in the lateral direction Y and improving the fit when the diaper 1 is worn, it is preferable that both ends of the stretchable member arrangement region R in the lateral direction Y are arranged outward in the lateral direction Y from the extension line of the leg gather elastic member 4 when it is hypothetically extended in the longitudinal direction X. When a plurality of leg gather elastic members 4 are arranged as in this embodiment, the extension line is determined based on the leg gather elastic member 4 that is outermost in the lateral direction Y. In order to ensure that such effects are achieved more reliably, it is preferable that the length W6 in the horizontal direction Y of the stretchable member arrangement region R, the length W7 between the outermost elastic members 4, 4 for leg gathers in the horizontal direction Y, and the length W6 in the horizontal direction Y of the stretchable member arrangement region R relative to the length W7 between the elastic members 4, 4 for leg gathers are in the following ranges. The length W6 of the elastic member arrangement region R in the lateral direction Y is preferably 150 mm or more and 330 mm or less, and more preferably 160 mm or more and 320 mm or less. The length W7 between the leg gather elastic members 4, 4 is preferably 100 mm or more and 210 mm or less, and more preferably 120 mm or more and 200 mm or less. The length W6 of the stretchable member disposing region R in the lateral direction Y relative to the length W7 between the leg gather elastic members 4, 4 is preferably 1.5 to 2.0, more preferably 1.6 to 1.8.

[0047] To facilitate the fastening operation of the fastening tape 6, it is preferable that the back-side elastic member 51 has at least one colored elastic member, and the color of the back-side elastic member 51 is visible when the diaper 1 is viewed from the skin-facing side. This configuration makes it easier to identify the side of the elastic member-arrangement region R that is longer in the lateral direction Y. This coloring can be performed, for example, by printing. Here, coloring refers to the presentation of a color other than white. Examples of colors of the back-side elastic member 51 include, but are not limited to, black, indigo blue, red, yellow, green, pink, purple, brown, yellow-green, light blue, and blue.

[0048] In this embodiment, when the diaper 1 is viewed from above, the back portion B is considered to be located on the top, bottom, left, and right, and the ventral portion A is located on the bottom. The side of the stretchable member arrangement region R that is longer in the lateral direction Y (the first region R1 side) is located on the right side (see FIGS. 1 and 4). This results in a greater stretch rate on the right side than on the left side, which has the advantage that right-handed people can more easily feel the tape stretch on their dominant hand side, further improving ease of putting on the diaper. A notice indicating that the absorbent article is suitable for right-handed wearers (e.g., parents of infants) may be displayed on the packaging of the absorbent article.

[0049] Next, the materials constituting the diaper 1 will be described. The topsheet 31 can be a liquid-permeable sheet, such as a nonwoven fabric or a perforated film. The topsheet 31 may have an uneven surface on its skin-facing side. For example, a plurality of scattered protrusions can be formed on the skin-facing side of the topsheet 31. Alternatively, ridges and grooves extending in one direction can be formed alternately on the skin-facing side of the topsheet 31. For such purposes, the topsheet 31 can be formed using two or more sheets of nonwoven fabric.

[0050] On the other hand, the back sheet 32 ​​may be a leakproof sheet, specifically a liquid-impermeable sheet (a sheet that does not allow liquid to pass through at all) or a sheet that is difficult to liquid-permeable (a sheet that is not liquid-impermeable but does allow liquid to pass through with difficulty), for example, a moisture-permeable resin film or a laminate of such a resin film and nonwoven fabric.

[0051] The absorbent core 331 is composed of, for example, a stack of hydrophilic fibers such as cellulose, including pulp, a mixed stack of the hydrophilic fibers and an absorbent polymer, a pile of absorbent polymer, a laminated structure in which an absorbent polymer is supported between two absorbent sheets, etc. The core wrap sheet may be, for example, tissue paper made of hydrophilic fibers or a liquid-permeable nonwoven fabric.

[0052] It is preferable that the cuff-forming sheet 71 is hydrophobic. For example, a hydrophobic nonwoven fabric can be used as the hydrophobic cuff-forming sheet 71. Specifically, an air-through nonwoven fabric, a spunbond nonwoven fabric, a spunbond-meltblown-spunbond laminated nonwoven fabric, or the like can be used. In addition, a hydrophobic resin film, a laminate of such a resin film and such a nonwoven fabric, or the like can be used.

[0053] Any of various known elastic materials used in absorbent articles such as diapers can be used without particular limitation as materials for forming the leg gather elastic members 4, the back elastic members 51, and the leakage-proof cuff-forming elastic members 72. Examples of materials include synthetic rubbers such as styrene-butadiene, butadiene, isoprene, and neoprene, natural rubber, EVA, stretchable polyolefin, and polyurethane, and the shapes that can be used include thread-like or string-like materials (such as flat rubber) with a rectangular, square, circular, or polygonal cross section, or multifilament thread-like materials.

[0054] The diaper 1 of the present invention is not limited to the embodiment shown in Figures 1 to 7. Another embodiment of the diaper 1 according to the present invention will be described below. In the following, the other embodiment will be described mainly with respect to components that differ from the embodiment shown in Figures 1 to 7, and similar components will be assigned the same reference numerals and will not be described again. For components that are not specifically described, the description of the embodiment shown in Figures 1 to 7 will be applied as appropriate.

[0055] Although the back-side elastic members 51 in the diaper 1 of the above-described embodiment include only elastic members longer than the absorber 33 in the lateral direction Y, the present invention is not limited to such a configuration. For example, as shown in FIG. 8, the back-side elastic members 51 may include a central back-side elastic member 51c whose lateral length in the lateral direction Y is longer than the absorber 33, and end elastic members 51d whose lateral length is shorter than the central back-side elastic member 51c. This configuration makes it easier to stretch one side (the first region R1 side) of the back portion B. To ensure this effect, it is preferable that the end elastic members 51d be positioned outward in the lateral direction Y from the central back-side elastic member 51c. In the embodiment shown in FIG. 8, the stretchable member-arrangement region R includes the end elastic members 51d.

[0056] Although the present invention has been described above based on the preferred embodiments, the present invention is not limited to the above embodiments and can be modified as appropriate. In addition, the above embodiments can be combined. For example, in the above-described embodiment, the length W1 of the first region R1 is longer than the length W2 of the second region R2, and the expansion rate of one side is greater than the expansion rate of the other side, but instead, the length W2 of the second region R2 may be longer than the length W1 of the first region R1, and the expansion rate of the other side may be greater than the expansion rate of one side.

[0057] In the above-described embodiment, the side of the stretchable member arrangement region R that is longer in the lateral direction Y is located on the right side in a plan view of the diaper 1 (see FIGS. 1 and 4), but instead, the side of the stretchable member arrangement region R that is longer in the lateral direction Y may be located on the left side. This provides a greater stretch rate on the left side than on the right side, which has the advantage that left-handed people will be more likely to feel the tape stretch on their dominant hand side, further improving ease of operation when putting on the diaper.

[0058] When the diaper 1 is viewed in plan, at least one of the back-side elastic members 51 has a different length in the lateral direction Y on one side and the other side of the longitudinal centerline CLx. However, from the viewpoint of reliably achieving the effects of the present invention, the number of back-side elastic members 51 having a different length in the lateral direction Y on one side and the other side is preferably 10% to 100%, more preferably 30% to 100%, of the total number of back-side elastic members 51. Although the back-side stretch sheet 50 includes a plurality of back-side elastic members 51, the back-side stretch sheet 50 may instead include a single back-side elastic member 51. The leakage preventing cuffs 7 do not have to include the leakage preventing cuff-forming elastic members 72. In other words, the leakage preventing cuffs 7 do not have to be configured to stand up toward the wearer's skin due to contraction of the elastic members arranged on the cuff-forming sheets 71. When the diaper 1 is viewed in plan, the area overlapping the absorber 33 may have a non-stretchable area where the back-side elastic members 51 do not exhibit stretchability. [Explanation of symbols]

[0059] 1 diaper 3. Absorbent body 4 Elastic material for leg gathers 6 Fastening Tape 7 Leak proof cuff 9 Attached area 10 Exterior sheet 31 Surface sheet 32 Back sheet 33 Absorbent 50 Back stretch sheet 51 Back elastic member R Elastic member placement area SF side flap

Claims

1. The garment has a vertical direction extending from the wearer's abdomen side through the crotch portion to the back side and a horizontal direction perpendicular to the vertical direction, and also has a crotch portion that is arranged in the crotch portion when worn, a abdomen-side portion that is arranged closer to the wearer's abdomen than the crotch portion, and a back-side portion that is arranged closer to the wearer's back than the crotch portion, An absorbent article comprising an absorbent main body including an absorbent body, and a pair of fastening tapes extending outward in the lateral direction from the lateral side portions of the back side portion, The back side portion has an elastic member arrangement region in which a back side elastic member extending in the lateral direction is arranged, When the absorbent article is viewed in plan, the stretchable member arrangement region has a different lateral length on one side and the other side of a vertical center line of the absorbent article that divides the length of the absorbent article in half in the lateral direction, When a band-shaped region in the back portion that overlaps with the stretchable member arrangement region in the vertical direction and extends over the entire length of the absorbent main body in the horizontal direction is defined as a back stretchable region, the stretch rate of the back stretchable region in the horizontal direction is different on one side and the other side of the absorbent article.

2. The absorbent article according to claim 1 , wherein at least a portion of the elastic member arrangement region is disposed between a pair of the fastening tapes in the longitudinal direction.

3. When the back-side stretchable region is divided into thirds in the vertical direction, and two-thirds of the region on the crotch side is designated as the crotch-side stretchable region, and the remaining region is designated as the back-side stretchable region, The absorbent article according to claim 1 or 2, wherein the stretch rate of the crotch-side stretchable region is greater than the stretch rate of the back-side stretchable region.

4. 3. The absorbent article of claim 1, wherein, when viewed in a plane, the side of the elastic member arrangement area with the longer horizontal length is defined as the one side, and the side of the elastic member arrangement area with the shorter horizontal length is defined as the other side, and on the one side, the end of the elastic member arrangement area and the fastening tape overlap.

5. The back-side elastic member includes a central back-side elastic member whose lateral length along the lateral direction is longer than the length of the absorbent body, and end elastic members whose lateral length is shorter than the central back-side elastic member, The absorbent article according to claim 1 or 2, wherein the end elastic members are located outward in the lateral direction from the central back elastic members.

6. The absorbent article according to claim 1 or 2, wherein the elastic member arrangement region is continuous in the lateral direction.

7. The back elastic member has at least one colored elastic member, The absorbent article according to claim 1 or 2, wherein the color of the elastic member is visible when the absorbent article is viewed from the skin-facing side.

8. Elastic members for leg gathers are arranged in a stretched state along the longitudinal direction on both side portions of the absorbent article in the longitudinal direction, 3. The absorbent article according to claim 1, wherein both ends of the elastic member arrangement region in the lateral direction are arranged laterally outward of an extension line of the leg gather elastic member when the leg gather elastic member is virtually extended in the vertical direction.

9. The absorbent article according to claim 1 or 2, wherein the rear-side stretchable member is a plurality of elastic members, and the plurality of elastic members are arranged intermittently in the longitudinal direction.

10. The absorbent article according to claim 3 , wherein, in a plan view of the absorbent article, at least a portion of the crotch-side elastic region in the longitudinal direction overlaps with the absorber.

11. In a plan view of the absorbent article, when the side of the elastic member arrangement region having a longer length in the lateral direction is defined as the one side, and the side of the elastic member arrangement region having a shorter length in the lateral direction is defined as the other side, The absorbent article according to claim 1 or 2, wherein the back-side stretchable region has a greater stretch rate in the lateral direction on the one side than on the other side.

12. The absorbent article according to claim 11, wherein, in a plan view of the absorbent article, when the dorsal portion is considered to be located on the upper side in the vertical and horizontal directions and the ventral portion is considered to be located on the lower side, the one side is located on the right side.

13. The absorbent article according to claim 11, wherein, in a plan view of the absorbent article, when the dorsal portion is considered to be located on the upper side in the vertical and horizontal directions and the ventral portion is considered to be located on the lower side, the one side is located on the left side.

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