Absorbent article

Abstract

To prevent users from making an impression as a tight product on an absorbent article by reducing a difference of extension between the time in attaching and during wearing.SOLUTION: An absorbent article includes an expanding and contracting region in which an elastic member (23, 33) expanding and contracting in a right-and-left direction is arranged in at least one of an abdominal side waist part (20) and a back side waist part (30). When at least a part of the expanding and contracting region is a test piece, a value obtained by dividing force measured in extending the test piece in the right-and-left direction at a speed of 50000 mm / min to a length of 84% of the maximum extension by a width in a vertical direction of the test piece is a first measured value, and a value obtained by dividing force measured in extending the test piece at a speed of 500 mm / min to a length of 84% of the maximum extension by the width is a second measured value, a value obtained by dividing the first measured value by the second measured value is smaller than 1.2.SELECTED DRAWING: Figure 4

Description

[Technical field]

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

[0002] Patent Document 1 discloses a stretchable sheet in which, in the stress-elongation ratio relationship obtained by stretching a stretchable sheet to twice its original length and then shrinking it at 300 mm / min using a tensile tester, the stress at 1.8 times the original length during the second cycle is defined as A and the stress at 1.8 times the original length during the second cycle is defined as B, and the value of B / A is 0.83 to 0.90. When this stretchable sheet is used as the exterior body of an absorbent article, A is a measure of how easily the absorbent article can be spread and B is a measure of how well the absorbent article fits, and the closer the value of B / A is to 1, the easier it is to put on the absorbent article and the less tight it feels when worn. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-199248 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when a user actually spreads the exterior body (waist circumference part) of the absorbent article in order to wear the absorbent article, the absorbent article is spread at a speed much faster than the elongation speed (300 mm / min) described in Patent Document 1. Therefore, there is a risk that the above value of A may deviate significantly from the ease with which the absorbent article can be spread when worn. On the other hand, while the absorbent article is being worn, the exterior body is expanded relatively slowly by the wearer's movements such as breathing, etc. Therefore, not only the stress B during contraction as in Patent Document 1, but also the elongation stress when the exterior body is slowly expanded is likely to affect the tightness felt by the wearer. In an absorbent article, if there is a large difference between how easily the waist part can be expanded (stretched) when worn and how easily the waist part can be expanded (stretched) while worn, and the user feels that it is difficult to expand the waist part when wearing the article, the user may have the impression that the product is tighter than the actual fit while wearing it.

[0005] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to reduce the difference in the ease of stretching of the waist area when put on and while not being worn, thereby preventing users from getting the impression that the absorbent article is a product that is too tight. [Means for solving the problem]

[0006] The main invention for achieving the above-mentioned object is an absorbent article having mutually intersecting vertical and horizontal directions, comprising an absorbent core, a ventral waist portion, and a rear waist portion, and having an elastic region in at least one of the ventral waist portion and the rear waist portion in which an elastic member capable of stretching in the horizontal direction is arranged, wherein at least a part of the elastic region is used as a test piece, the test piece is stretched in the horizontal direction to 84% of its maximum elongation length at a speed of 50,000 mm / min, the force measured when the test piece is stretched in the horizontal direction to 84% of its maximum elongation length at a speed of 50,000 mm / min is divided by the vertical width of the test piece, the force measured when the test piece is stretched in the horizontal direction to 84% of its maximum elongation length at a speed of 500 mm / min is divided by the width, and the value obtained by dividing the first measurement value by the second measurement value is smaller than 1.2. Other features of the present invention will become apparent from the following detailed description of the present invention and the accompanying drawings. Effect of the Invention

[0007] According to the present invention, the difference in the ease of stretching of the waist area between when it is put on and when it is not being worn can be reduced, and the user's impression that the absorbent article is a product that is too tight can be suppressed. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view of a pants-type disposable diaper 1. [Diagram 2] FIG. 1 is a schematic plan view of a diaper 1 in an unfolded and extended state, as viewed from the wearer's skin side. [Diagram 3] FIG. 3 is a schematic cross-sectional view taken along line AA in FIG. [Figure 4] 4 is an explanatory diagram of the welded portion rows Ra, Rb, and Rc provided on the abdominal-side waist portion 20. FIG. [Diagram 5] 5A and 5B are explanatory diagrams of the attachment function of the waistline elastic members 23. FIG. [Figure 6] 6A to 6C are enlarged views of parts of the welded portion rows Ra, Rb, and Rc. [Figure 7] 7A and 7B are explanatory diagrams of the tensile test of the waist portions 20 and 30. FIG. [Figure 8] FIG. 13 shows the results of a tensile test. [Figure 9] FIG. 13 shows the results of a tensile test. [Figure 10] 10A and 10B are explanatory diagrams of the waistline elastic member 23. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] At least the following points will become apparent from the description of this specification and the accompanying drawings. Aspect 1 is an absorbent article having a vertical direction and a horizontal direction that intersect with each other, comprising an absorbent core, a ventral waist portion, and a rear waist portion, and having a stretchable region in at least one of the ventral waist portion and the rear waist portion in which an elastic member that is stretchable in the horizontal direction is arranged, wherein at least a portion of the stretchable region is used as a test piece, the test piece is stretched in the horizontal direction at a speed of 50,000 mm / min to 84% of its maximum elongation length, and the force measured when the test piece is stretched in the horizontal direction at a speed of 50,000 mm / min is divided by the vertical width of the test piece, which is a first measurement value, the force measured when the test piece is stretched in the horizontal direction at a speed of 500 mm / min to 84% of its maximum elongation length, and the force measured when the test piece is stretched in the horizontal direction at a speed of 500 mm / min is divided by the width, which is a second measurement value, and the value obtained by dividing the first measurement value by the second measurement value is smaller than 1.2.

[0010] According to the first aspect, the first measurement value during high-speed elongation can be suppressed and the difference between the first measurement value during high-speed elongation and the second measurement value during low-speed elongation can be reduced, compared to when the value obtained by dividing the first measurement value by the second measurement value is 1.2 or more. This makes it easier to expand (stretch) the waist portion when worn, and reduces the difference in fit (tightness) while worn. This prevents the user from getting the impression that the absorbent article is a product that is too tight.

[0011] Aspect 2 is an absorbent article according to aspect 1, characterized in that in a test in which the test piece is stretched at a speed of 50,000 mm / min to a length that is 84% ​​of its maximum elongation, and then 15 seconds after the start of elongation, the test piece is contracted to a length that is 66% of its maximum elongation, the force measured when the test piece is contracted to 66% of its maximum elongation is divided by the width, a third measurement value is obtained, and a fourth measurement value is obtained by dividing the force measured 585 seconds after the test piece is contracted to 66% of its maximum elongation by the width, and the value obtained by dividing the fourth measurement value by the third measurement value is 0.95 or more.

[0012] According to the second aspect, the third measurement value when the waist portion is significantly stretched and then contracted can be suppressed, and the difference from the fourth measurement value when the contraction stabilizes can be reduced, compared to when the value obtained by dividing the fourth measurement value by the third measurement value is less than 0.95. This can reduce the feeling of tightness when the waist portion contracts to fit the wearer when worn (i.e., immediately after wearing). Conversely, the fit is maintained even if the stretched state continues to fit the wearer.

[0013] Aspect 3 is a pants-type absorbent article in which the ventral waist portion and the rear waist portion are joined by a pair of side joining portions on both sides in the left-right direction, The absorbent article of aspect 1 or 2, characterized in that the test specimen is a portion of the ventral waist portion and the dorsal waist portion that are joined in a ring shape by the side joint, the portion being above the vertical center of the side joint.

[0014] According to aspect 3, the upper half of the waist portion is likely to affect the ease of expansion of the waist portion and the feeling of tightness when worn. Therefore, in the upper half of the waist portion, if the value obtained by dividing the first measurement value by the second measurement value is 1.2 or less, or the value obtained by dividing the fourth measurement value by the third measurement value is 0.95 or more, the waist portion becomes easier to expand and the feeling of tightness immediately after wearing can be further reduced.

[0015] Aspect 4 is an absorbent article described in any one of aspects 1 to 3, characterized in that, in the stretchable region, the elastic member is arranged between a pair of sheets joined by a plurality of welds, and when the elastic member is contracted in the left-right direction, it is sandwiched between two of the welds adjacent to each other in the vertical direction, thereby regulating the vertical position of the elastic member relative to the pair of sheets.

[0016] According to the fourth aspect, the amount of adhesive used in the waist portion can be reduced. Therefore, when the waist portion is stretched at high speed, the effect of the hardness of the adhesive can be reduced, and the first measurement value can be suppressed, and the difference with the second measurement value can be reduced.

[0017] Aspect 5 is a pants-type absorbent article in which the ventral waist portion and the rear waist portion are joined by a pair of side joints on both sides in the left-right direction, and the absorbent article described in aspect 4 is characterized in that in at least one of the ventral waist portion and the rear waist portion, a plurality of the elastic members are arranged at intervals in the vertical direction, and all of the elastic members that overlap with the side joints in the vertical direction are sandwiched between two of the welded portions adjacent to each other in the vertical direction when contracted in the left-right direction, thereby regulating the vertical position relative to the pair of sheets.

[0018] According to aspect 5, the amount of adhesive used in the waist portion can be reduced. Therefore, when the waist portion is stretched at high speed, the effect of the hardness of the adhesive can be reduced, and the first measurement value can be suppressed, and the difference with the second measurement value can be reduced.

[0019] Aspect 6 is an absorbent article as described in aspect 4 or 5, characterized in that the multiple welded portions include multiple pairs of welded portions that are adjacent to each other in the vertical direction and sandwich the elastic member, the multiple pairs of welded portions include a first pair of welded portions and a second pair of welded portions that are located toward the center in the left-right direction than the first pair of welded portions, and the second pair of welded portions has a longer length in the vertical direction between the welded portions sandwiching the elastic member than the first pair of welded portions.

[0020] According to the sixth aspect, the elastic member can be prevented from coming off the first pair of welded portions, and the waistband can be stretched over a wide range in the left-right direction. The second pair of welded portions can restrict the vertical position of the elastic member while preventing the sheet from floating. Therefore, compared to the case where the sheet is prevented from floating by adhesive, the amount of adhesive used in the waistband can be reduced, and the difference between the first measurement value and the second measurement value can be reduced.

[0021] Aspect 7 is an absorbent article described in any of aspects 4 to 6, characterized in that the multiple welded portions include multiple pairs of welded portions that are adjacent to each other in the vertical direction and are positioned on either side of the elastic member, the multiple welded portion pairs include a third pair of welded portions and a fourth pair of welded portions that are positioned more centrally in the left-right direction than the third pair of welded portions, and the fourth pair of welded portions has a shorter length in the left-right direction than the third pair of welded portions.

[0022] According to the seventh aspect, the elastic member is prevented from coming off the third pair of welded parts, and the waist part is stretchable over a wide range in the left-right direction. The fourth pair of welded parts restricts the position of the elastic member, and the friction between the elastic member and the welded parts is reduced, making it easier to expand the waist part. This prevents the user from getting the impression that the product is too tight.

[0023] Aspect 8 is an absorbent article described in any of aspects 4 to 7, characterized in that the elastic region has a first elastic member and a second elastic member adjacent to each other and spaced apart in the vertical direction, the multiple welded portions have a first welded portion adjacent to the first elastic member and a second welded portion located in the center in the vertical direction between the first elastic member and the second elastic member, and the first welded portion has a stronger weld strength than the second welded portion.

[0024] According to the eighth aspect, the position of the elastic member can be firmly regulated by the first welded portion having high rigidity. The second welded portion having low rigidity can suppress the lifting of the sheet while ensuring the flexibility of the waist portion. Therefore, compared to the case where the lifting of the sheet is suppressed by adhesive, the amount of adhesive used in the waist portion can be reduced, and the first measurement value can be suppressed, and the difference with the second measurement value can be reduced.

[0025] Aspect 9 is an absorbent article described in any of aspects 4 to 8, characterized in that when the stretchable region is stretched in the left-right direction, the vertical length between two welded portions that are adjacent in the vertical direction and sandwich the elastic member is greater than the vertical length of the elastic member.

[0026] According to the ninth aspect, as the waist portion shrinks in the left-right direction, the elastic member becomes thinner and the restraint by the welded portion weakens. This makes it easier to expand the waist portion, and prevents the user from getting the impression that the product is too tight.

[0027] Aspect 10 is a pants-type absorbent article in which the ventral waist portion and the rear waist portion are joined by a pair of side joints on both sides in the left-right direction, and the absorbent article is characterized in that it comprises an absorbent main body including the absorbent core and an outer body, and in that, when the absorbent article is in an unfolded state, the stretchable region has a region in which the number of sheets stacked in the outer body is two layers, a pair of sheets sandwiching the elastic member.The absorbent article described in any of aspects 1 to 9.

[0028] According to the tenth aspect, the area where the sheets are laminated and joined with an adhesive can be made smaller, and the amount of adhesive used in the waist portion can be reduced. Therefore, the first measurement value can be reduced, and the difference with the second measurement value can be reduced.

[0029] Aspect 11 is a pants-type absorbent article in which the ventral waist portion and the rear waist portion are joined by a pair of side joints on both sides in the left-right direction, the absorbent article comprising an absorbent main body including the absorbent core, and in at least one of the ventral waist portion and the rear waist portion, a folded-back portion is provided in which an upper end portion of at least one of a pair of sheets sandwiching the elastic member is folded downward in the vertical direction, and an area where no adhesive is applied is provided between the upper end of the absorbent main body and the lower end of the folded-back portion. The absorbent article described in any of aspects 1 to 10 is characterized in that

[0030] According to the eleventh aspect, the amount of adhesive used on the waist portion can be reduced, thereby making it possible to suppress the first measurement value and reduce the difference with the second measurement value.

[0031] Aspect 12 is an absorbent article described in any of aspects 1 to 11, characterized in that a lubricant is adhered to at least one of the surface of the elastic member and the inner surfaces of the pair of sheets that sandwich the elastic member.

[0032] According to the twelfth aspect, the frictional force generated between the elastic member and the sheet can be reduced, making it easier to expand the waist area, and thus preventing the user from getting the impression that the product is too tight.

[0033] Aspect 13 is an absorbent article as described in any of aspects 1 to 12, characterized in that when the dorsal waist portion is used as the test specimen, the value obtained by dividing the first measurement value by the second measurement value is smaller than the value obtained by dividing the first measurement value by the second measurement value when the ventral waist portion is used as the test specimen.

[0034] According to the thirteenth aspect, the rear waist portion is easily stretched even at high speeds, and the rear waist portion can be easily expanded significantly to cover the buttocks when the absorbent article is worn.

[0035] Aspect 14 is an absorbent article as described in any of aspects 1 to 12, characterized in that when the ventral waist portion is used as the test specimen, the value obtained by dividing the first measurement value by the second measurement value is smaller than the value obtained by dividing the first measurement value by the second measurement value when the dorsal waist portion is used as the test specimen.

[0036] According to aspect 14, the ventral waist portion stretches easily even at high speeds and expands easily when the absorbent article is worn, thereby preventing the wearer's feet (especially the toes) from getting caught when passing their feet through the waist opening.

[0037] Aspect 15 is an absorbent article in the form of a pants-type absorbent article in which the ventral waist portion and the rear waist portion are joined by a pair of side joints on both sides in the left-right direction, and the absorbent article is characterized in that, in the unfolded state of the absorbent article, the portion of the absorbent core that overlaps with the rear waist portion in its thickness direction has a lower average basis weight of the absorbent core than the portion of the absorbent core that overlaps with the ventral waist portion in its thickness direction.

[0038] According to the fifteenth aspect, the rigidity of the absorbent core in the rear waist portion is suppressed, and the rear waist portion can be easily expanded. Therefore, the rear waist portion can be easily expanded to a large extent so as to cover the buttocks of the wearer. Meanwhile, the basis weight of the absorbent core in the ventral waist portion close to the urination area is increased, thereby suppressing leakage.

[0039] === Implementation form === Hereinafter, a pants-type disposable diaper for infants will be exemplified as an absorbent article according to this embodiment. However, the absorbent article is not limited to the above and may be any absorbent article having a ventral waist portion and a rear waist portion, such as pants-type diapers for adults, shorts-type napkins, tape-type diapers, etc.

[0040] <<Basic configuration of pants-type disposable diaper 1>> Fig. 1 is a schematic perspective view of a pants-type disposable diaper 1 (hereinafter also referred to as "diaper"). Fig. 2 is a schematic plan view of the diaper 1 in an unfolded and extended state, as viewed from the wearer's skin side. Fig. 3 is a schematic cross-sectional view taken along line AA in Fig. 2.

[0041] The diaper 1 has a vertical direction, a horizontal direction, and a front-to-rear direction that intersect with each other, and has a waist opening BH and a pair of leg openings LH. In the vertical direction, the side of the waist opening BH is the upper side, and the side that corresponds to the wearer's crotch is the lower side. In the front-to-rear direction, the side that corresponds to the wearer's abdomen is the front side, and the side that corresponds to the back is the rear side. The diaper 1 also has a thickness direction in which materials are layered as shown in Figure 3, and the side in the thickness direction that contacts the wearer is the skin side, and the opposite side is the non-skin side.

[0042] The diaper 1 has an absorbent body 10 and a pair of waist-line sections 20, 30. The pair of waist-line sections 20, 30 are joined to the non-skin side of the absorbent body 10 with an adhesive or the like. Of the pair of waist-line sections 20, the one located at the front is also referred to as a ventral waist-line section 20, and the one located at the rear is also referred to as a dorsal waist-line section 30. The ventral waist-line section 20 and the dorsal waist-line section 30 are joined at both left and right sides by a pair of side joint sections SS. Examples of the joining method using the side joint sections SS include heat welding, ultrasonic welding, and joining methods using an adhesive.

[0043] As shown in Fig. 3, the absorbent body 10 has an absorbent core 11, a liquid-permeable top sheet 12 arranged closer to the skin than the absorbent core 11, a liquid-impermeable back sheet 13 arranged closer to the skin than the absorbent core 11, and an exterior sheet 14. The absorbent core 11 may be any material that absorbs and retains excreted liquid, and may be, for example, a liquid-absorbent material such as pulp fiber or a highly absorbent polymer molded into a predetermined shape. The absorbent core 11 may also be covered with a liquid-permeable sheet such as tissue paper or a nonwoven fabric.

[0044] 2, leg-hole elastic members 15 (e.g., rubber thread) that stretch along the longitudinal direction of the absorbent main body 10 may be provided on both lateral sides of the absorbent main body 10. Furthermore, leakage prevention wall portions that can stand up on the skin side may be provided on the lateral inner side of the leg-hole elastic members 15. The leakage prevention wall portions are formed, for example, by folding back both lateral sides of the exterior sheet 14 inward in the lateral direction so as to be positioned on the skin-facing side of the top sheet 12, and providing leakage prevention wall elastic members 16 (e.g., rubber thread) that stretch in the longitudinal direction at the folded back portions.

[0045] In this embodiment, the portion overlapping the side joint portion SS in the vertical direction is the waist portion 20, 30, and the ventral waist portion 20 and the back waist portion 30 are rectangular portions in a plan view. An extension portion 30E having a substantially trapezoidal shape is provided on the crotch side of the back waist portion 30. The extension portion 30E can cover the buttocks of the wearer. In the following description, the back waist portion 30 and the extension portion 30E are collectively referred to as the back exterior portion 30, 30E. However, this is not limited to the above, and for example, the configuration may not have the extension portion 30E on the back side, or may have a portion extending from the ventral waist portion 20 to the crotch side.

[0046] The ventral waist portion 20 and the back side exterior portion 30, 30E each have a skin side sheet 21, 31, a non-skin side sheet 22, 32, and waist elastic members 23, 33 (e.g., rubber thread) that are stretchable in the left-right direction. The multiple waist elastic members 23, 33 are arranged at intervals in the up-down direction between the skin side sheet 21, 31 and the non-skin side sheet 22, 32.

[0047] The skin side sheets 21, 31 and the non-skin side sheets 22, 32 are preferably flexible sheet members, and examples of such materials include spunbond nonwoven fabric, meltblown nonwoven fabric, SMS (spunbond / meltblown / spunbond) nonwoven fabric, etc. The constituent fibers of the nonwoven fabric are not limited to single fibers of polypropylene (PP), a typical example of thermoplastic resin, but may be single fibers of other thermoplastic resins such as polyethylene (PE), or may further be composite fibers having a sheath-core structure such as PE and PP.

[0048] The basic configuration of the diaper 1 has been described above, but the above-mentioned configuration of the diaper 1 is merely an example and is not limited thereto. For example, in the diaper 1 of this embodiment, the ventral waist portion 20 and the rear exterior portions 30, 30E are formed of separate members, and the non-skin side of the absorbent body 10 is exposed in the crotch portion. The present invention is not limited thereto, and may be, for example, a diaper having an exterior member formed of three members, namely, the ventral waist portion 20, the rear exterior portions 30, 30E, and the crotch portion connecting them, or a diaper having an exterior member formed of a single member that is continuous from the ventral waist portion 20 to the rear waist portion 30.

[0049] <<About waist circumference parts 20 and 30>> Fig. 4 is an explanatory diagram of the welded portion rows Ra, Rb, Rc provided on the abdominal-side waistline portion 20. Figs. 5A and 5B are explanatory diagrams of the attachment function of the waistline elastic member 23. Figs. 6A to 6C are enlarged views of parts of the welded portion rows Ra, Rb, Rc.

[0050] 4 and other drawings show a state in which the ventral waist portion 20 is stretched in the left-right direction. The state in which the waist portions 20, 30 (stretchable regions) are stretched in the left-right direction refers to a state in which the waist portions 20, 30 are stretched to such an extent that wrinkles that have occurred in the waist portions 20, 30 are substantially no longer visible, and the dimensions of each member (e.g., skin side sheet 21, etc.) constituting the waist portions 20, 30 are stretched to lengths that match or are close to the dimensions of the member alone (i.e., the dimensions when the elastic member does not exhibit stretchability).

[0051] <Regarding the position of the waist elastic member 23> The ventral waist portion 20 and the back waist portion 30 are composed of stretchable sheets in which multiple waist elastic members 23, 33 (elastic members) stretchable in the left-right direction are arranged at intervals in the up-down direction between the skin side sheets 21, 31 and the non-skin side sheets 22, 32 (between a pair of sheets) joined by multiple welding parts 50. The skin side sheets 21, 31 and the non-skin side sheets 22, 32 are intermittently joined by multiple welding parts 50 that are discretely arranged in the up-down and left-right directions. Examples of methods for forming the welding parts 50 include well-known welding methods such as ultrasonic welding and heat welding.

[0052] The pair of sheets joined by the welded portion 50 may be two separate sheets, such as the skin side sheets 21, 31 and the non-skin side sheets 22, 32 in this embodiment, or may be a two-layer sheet formed by folding back one sheet. Furthermore, the welded portion 50 is not limited to joining only the pair of sheets sandwiching the waist elastic members 23, 33, but may join three or more layers of sheets, including a sheet laminated on the pair of sheets.

[0053] Since the ventral body circumferential portion 20 and the dorsal body circumferential portion 30 have substantially the same configuration, the ventral body circumferential portion 20 will be described below as a representative of both. The ventral body circumferential portion 20 has a plurality of welding portion rows Ra, Rb, Rc in which a plurality of welding portions 50 are arranged in the vertical direction. The plurality of welding portion rows Ra, Rb, Rc are arranged at intervals in the left - right direction. As shown in Fig. 5A, the vertical positions of the spaces (non - welding portions) through which the body circumferential elastic member 23 passes are aligned, and the body circumferential elastic member 23 can be arranged along the left - right direction. However, the vertical positions of the non - welding portions adjacent to each other in the left - right direction may be offset. Even in this case, the ventral body circumferential portion 20 can be given elasticity in the left - right direction.

[0054] As shown in Fig. 5A, two welding portions 50 adjacent to each other in the vertical direction and sandwiching the body circumferential elastic member 23 are also called "welding portion pair 51". The upper welding portion 50 and the lower welding portion 50 forming the welding portion pair 51 are arranged with a space GH in the vertical direction. The size of the space GH is set to be the same size as or slightly larger than the outer diameter d1 of the body circumferential elastic member 23 in the state where the ventral body circumferential portion 20 is maximally extended in the left - right direction (GH≧d1).

[0055] However, the body circumferential elastic member 23 becomes thicker as it contracts in the left - right direction. Therefore, as shown in Fig. 5B, the space GH between the welding portion pair 51 is made smaller than the maximum outer shape d2 of the body circumferential elastic member 23 in the state where the body circumferential elastic member 23 contracts in the left - right direction (that is, the natural state of the ventral body circumferential portion 20) (GH < d2). By doing so, the body circumferential elastic member 23 in the contracted state in the left - right direction is sandwiched between the welding portion pair 51 (the vertical expansion is restricted). Therefore, the positions (movements) of the body circumferential elastic member 23 in the left - right direction and the vertical direction with respect to the skin - side sheet 21 and the non - skin - side sheet 22 are restricted.

[0056] Therefore, even without using an adhesive to fix the waist elastic members 23 to the skin side sheet 21 and the non-skin side sheet 22, it is possible to prevent the waist elastic members 23 from shifting position, and the stretchability of the ventral side waist portion 20 is maintained. In other words, by using the welded portion 50, it is possible to attach the waist elastic members 23 to the skin side sheet 21 and the non-skin side sheet 22 without using an adhesive or by reducing the amount of adhesive used. Therefore, it is possible to prevent a decrease in the flexibility of the ventral side waist portion 20 (stretchable sheet 40) due to hardening of the adhesive. Also, it is possible to prevent a decrease in the elastic properties of the waist elastic members 23 due to hardening of the adhesive.

[0057] In the abdominal-side waist portion 20, the waist elastic member 23 is fixed to the skin-side sheet 21 and the non-skin-side sheet 22 at the side joint SS. More specifically, during the manufacture of the diaper 1, the side joint SS is formed with the waist elastic member 23 in a stretched state sandwiched between the skin-side sheet 21 and the non-skin-side sheet 22, and the ends of the waist elastic member 23 are fixed to the side joint SS. Therefore, even if the abdominal-side waist portion 20 stretches significantly when the diaper 1 is worn, it is possible to prevent the waist elastic member 23 from slipping out from between the welded portions 51, and the stretchability of the abdominal-side waist portion 20 is maintained.

[0058] Furthermore, the relationship between the distance GH between the pairs of welded parts 51 and the outer diameters d1, d2 of the waistline elastic member 23 is not limited to the above. For example, a part of the waistline elastic member 23 may overlap the welded part 50 to the extent that the waistline elastic member 23 is not torn. In this case as well, the waistline elastic member 23 is sandwiched between the pairs of welded parts 51 in a state in which it is contracted in the left-right direction, and its position in the left-right direction and the up-down direction relative to the skin side sheet 21 and the non-skin side sheet 22 is regulated.

[0059] Furthermore, the positions of all the waistline elastic members 23 (elastic members) arranged in the ventral waist portion 20 are not necessarily restricted by being sandwiched between the pair of welded parts 51. The positions of some of the waistline elastic members 23 may be restricted by the pair of welded parts 51, and another part of the waistline elastic members 23 may be fixed to the skin side sheet 21 and the non-skin side sheet 22 with an adhesive.

[0060] <<Ease of stretching of waist portions 20, 30>> Figures 7A and 7B are explanatory diagrams of the tensile test of the waist portions 20 and 30. Figures 8A, 8B, 9A, and 9B are diagrams showing the results of the tensile test.

[0061] The diaper 1 has elastic regions in which waist elastic members 23, 33 (elastic members) capable of stretching in the left-right direction are arranged in the ventral waist portion 20 and the rear waist portion 30. When a user (parent, caregiver, etc.) of the pants-type diaper 1 puts the diaper 1 on a wearer (child), first, inserts both hands through the leg openings LH or waist opening BH and quickly spreads the annular waist portions 20, 30 in the left-right direction. After that, the wearer's legs are passed from the waist openings BH toward the leg openings LH, and the diaper 1 is pulled up to complete putting on the diaper.

[0062] At this time, the speed at which the user spreads the waist-circumference portions 20, 30 in the left-right direction is fast, taking less than one second. On the other hand, while the diaper 1 is being worn, the waist-circumference portions 20, 30 are spread relatively slowly due to the wearer's movements such as breathing.

[0063] As a result of the applicant's intensive research, for example, the following was found about a general waist part in which an adhesive such as a hot melt adhesive is continuously applied in the longitudinal direction of the waist elastic member to fix the waist elastic member to a sheet: When the waist part is stretched at high speed, the elongation stress (resistance of the waist part during elongation) is higher than when the waist part is stretched at low speed, and the difference is large.

[0064] This is believed to be due to the influence of the adhesive that had hardened when the waist portion was in a contracted state. When the waist portion is expanded at a low speed, the hardened resin can be gradually deformed, but when the waist portion is expanded at a high speed, the hardened resin must be deformed all at once, and the resistance of the adhesive is believed to affect the elongation stress (difficulty of expansion) of the waist portion. In particular, since diapers are packaged in a contracted state for a long period of time and distributed, the degree of hardening of the adhesive is likely to increase. Therefore, when the waist portion of the diaper is first expanded after being taken out of the package in order to put on the diaper, it is believed to be more susceptible to the hardening of the adhesive. A user who feels the difficulty of expanding the waist portion when putting on the diaper 1 (high stress when stretching at high speed) may have the impression that the product is tighter than the fit of the waist portion when actually wearing it (low stress when stretching at low speed).

[0065] Therefore, in the diaper 1, the difference between the elongation stress when the waist-surrounding portions 20, 30 are elongated at a high speed and the elongation stress when the waist-surrounding portions 20, 30 are elongated at a low speed is made as small as possible. First, a part of the stretchable region of the waist portions 20, 30 is taken as a test piece T. Then, as shown in Figures 7A and 7B, the force (N) measured when the test piece T is stretched in the left-right direction to 84% of its maximum length at a speed of 50,000 mm / min is divided by the vertical width (mm) of the test piece T to obtain a first measurement value A1 (N / mm). In addition, the force (N) measured when the test piece T is stretched in the left-right direction to 84% of its maximum length at a speed of 500 mm / min is divided by the vertical width (mm) of the test piece to obtain a second measurement value A2 (N / mm). The value obtained by dividing the first measurement value A1 by the second measurement value A2 is smaller than 1.2. A1 (stress during high-speed elongation) / A2 (stress during low-speed elongation) < 1.2.

[0066] The stress during high-speed elongation (first measurement value A1) corresponds to the resistance force felt by the user from the waist portions 20, 30 when the user quickly expands the waist portions 20, 30 when putting on the diaper 1. On the other hand, the stress during low-speed elongation (second measurement value A2) corresponds to the resistance force (fit feeling) felt by the wearer from the waist portions 20, 30 when performing slow movements such as breathing.

[0067] Therefore, according to the diaper 1 of this embodiment, the stress during high-speed elongation (first measurement value A1) is suppressed and the difference between the stress during low-speed elongation (second measurement value A2) is smaller than when the value obtained by dividing the first measurement value A1 by the second measurement value A2 is 1.2 or more. In other words, the difference between the ease of elongation of the waist-surrounding portions 20, 30 when the diaper 1 is put on and the ease of elongation of the waist-surrounding portions 20, 30 while being worn can be made smaller. Therefore, when the waist-surrounding portions 20, 30 are quickly stretched to put on the diaper 1, they can be stretched with a small force, and the ease of putting on the diaper 1 is improved. In addition, it is possible to prevent the user from having the impression that the product is tighter than the fit of the waist-surrounding portions 20, 30 while being worn (low stress during low-speed elongation).

[0068] In particular, in the case of the baby diaper 1 of this embodiment or the nursing diaper, the user (parent, caregiver, etc.) does not actually wear the diaper 1, so that the feeling of tightness while wearing it can be easily judged by the ease of expanding the waist portions 20, 30 when putting it on. Even in such cases, according to the diaper 1 of this embodiment, the waist portions 20, 30 can be easily expanded even at high speeds, so that the user can be prevented from getting the impression that the product is too tight.

[0069] In addition, the fact that the stress during high-speed elongation is suppressed means that the waist portions 20, 30 can easily elongate (have good conformity) even when the wearer moves quickly, making it easier for the wearer to move. Conversely, in the diaper 1, the stress during low-speed elongation is not too low, so that the diaper provides an appropriate fit while being worn.

[0070] In the stretchable regions of the waist portions 20, 30, waist elastic members 23, 33 are disposed between a pair of sheets (21 and 22, 31 and 32) joined by a plurality of welding parts 50. When contracted in the left-right direction, the waist elastic members 23, 33 are sandwiched between two vertically adjacent welding parts 50 as shown in Fig. 5B, thereby restricting their vertical positions with respect to the pair of sheets.

[0071] This makes it possible to reduce the amount of adhesive used to regulate the positions of the waist elastic members 23, 33 relative to the sheet. This therefore makes it possible to reduce the effect of hardening of the adhesive even when the waist portions 20, 30 are stretched at high speed, thereby suppressing the stress during high-speed stretching (first measured value A1) and reducing the difference with the stress during low-speed stretching (second measured value A2).

[0072] However, without being limited to the above, the waist elastic members 23, 33 may be attached to the sheet using an adhesive without using the welded portion 50. In that case, it is preferable to adjust the application pattern and application amount of the adhesive so that the value obtained by dividing the first measurement value A1 by the second measurement value A2 is smaller than 1.2, so as to reduce the effect of the hardening of the adhesive on high-speed elongation.

[0073] In this embodiment, the waist elastic members 23, 33 are attached to the sheet by the welded parts 50 in both the ventral waist portion 20 and the back waist portion 30, but the waist elastic members may be attached to the sheet by adhesive in one of the waist portions. In addition, when the back waist portion 30 has an extension portion 30E below the side joint portion SS and an elastic member is arranged along the left-right direction in the extension portion 30E, unlike in Fig. 2, the elastic member may be attached to the sheet by the welded parts 50 or by adhesive.

[0074] In addition, as shown in Figures 7A and 7B, in a test in which test piece T is stretched at a speed of 50,000 mm / min to a length that is 84% ​​of the maximum elongation, and then contracted to a length that is 66% of the maximum elongation 15 seconds after the start of elongation, the following is preferable. First, the force (N) measured when the test piece T is contracted to a length of 66% of its maximum elongation is divided by the vertical width (mm) of the test piece T to obtain a third measurement value A3 (N / mm). In addition, the force (N) measured 585 seconds after test piece T has contracted to 66% of its maximum elongation (i.e., 600 seconds after the start of the test) is divided by the vertical width (mm) of test piece T to obtain the fourth measurement value (N / mm). The value obtained by dividing the fourth measurement value A4 by the third measurement value A3 is preferably 0.95 or more. It is preferable that A4 (stress when shrinkage is stable) / A3 (stress immediately after shrinkage)≧0.95.

[0075] When putting on the diaper 1, the user greatly stretches the waist portions 20, 30 (for example, to about 84% of the maximum elongation), and then the waist portions 20, 30 contract to fit the wearer's waist (for example, to about 66% of the maximum elongation). Immediately after the waist portions 20, 30 contract, a relatively large tightening force (stress when the waist portions 20, 30 return to their original position, third measured value A3) acts on them. This tightening force decreases and stabilizes over time.

[0076] According to the diaper 1 of this embodiment, the third measurement value A3 immediately after contraction of the waist portions 20, 30 is suppressed and approaches the fourth measurement value A4, compared with the case where the value obtained by dividing the fourth measurement value A4 by the third measurement value A3 is smaller than 0.95. Therefore, the strong tightening force immediately after the waist portions 20, 30 of the diaper 1 fit the wearer is reduced, and the discomfort immediately after putting on the diaper can be reduced. Conversely, even if the waist portions 20, 30 continue to be stretched to fit the wearer, the fourth measurement value A4 does not decrease too much, and the fit can be maintained. However, the above is not limited, and the value obtained by dividing the fourth measurement value A4 by the third measurement value A3 may be less than 0.95.

[0077] 7A, it is preferable that the test piece T is the entire area of ​​the ventral waist portion 20 and the rear waist portion 30 which are joined in an annular shape by the side joining portion SS. In that case, since the above-mentioned relationship of the measured values ​​(A1 / A2<1.2, A4 / A3≧0.95) is established, it can be said that the difference in stress between when the diaper 1 is actually put on and when it is close to being worn is small, and also that the feeling of tightness immediately after putting on the diaper is suppressed.

[0078] Furthermore, even if the test piece T is a portion Au (see FIG. 2) above the vertical center CL of the side joint SS in the ventral waist portion 20 and the dorsal waist portion 30 that are joined in a ring shape by the side joint SS as shown in FIG. 7B, it is preferable that the above-mentioned relationship of the measurement values ​​(A1 / A2<1.2, A4 / A3≧0.95) is satisfied.

[0079] The upper part Au of the waistline parts 20, 30 is more likely to affect the ease of expansion and tightness of the waistline parts 20, 30 than the lower parts. Therefore, by suppressing the stress (A1) during high-speed elongation in the upper part Au of the waistline parts 20, 30 and reducing the difference with the stress (A2) during low-speed elongation, the waistline parts 20, 30 can be expanded more easily and the impression that the product is too tight can be reduced. Also, the tightness immediately after putting on the waistline parts 20, 30 can be reduced.

[0080] Furthermore, the test piece T is not limited to the annular waist portions 20, 30, but may be the ventral waist portion 20 separated at the side joint portion SS or the dorsal waist portion 30. In this case, when the back waist portion 30 is used as the test specimen T, it is preferable that the value obtained by dividing the first measurement value A1 by the second measurement value A2 is smaller than the value obtained by dividing the first measurement value A1 by the second measurement value when the ventral waist portion 20 is used as the test specimen T. In other words, it is preferable that the stress (A1) during high-speed elongation of the back waist portion 30 is suppressed and the difference between the stress (A2) during low-speed elongation is small. This makes it easier for the back waist portion 30 to elongate even at high speeds, and allows the back waist portion 30 to be greatly expanded so as to cover the buttocks when the diaper 1 is worn.

[0081] Conversely, when the ventral waist portion 20 is used as the test specimen T, the value obtained by dividing the first measurement value A1 by the second measurement value A2 may be smaller than the value obtained by dividing the first measurement value A1 by the second measurement value A2 when the back waist portion 30 is used as the test specimen T. In other words, the ventral waist portion 20 may have a smaller stress (A1) during high-speed elongation and a smaller difference with the stress (A2) during low-speed elongation. In that case, the ventral waist portion 20 is more likely to elongate even at high speeds and to expand easily when the diaper 1 is put on, so that the wearer's feet (especially the toes) are less likely to get caught when passing the feet through the waist opening BH.

[0082] The absorbent article is not limited to the pants-type diaper 1, but may be a tape-type diaper. In this case, for example, a stretchable region (so-called back side gather portion) may be provided in the left-right center of the rear waist circumference portion (the back side region when the product length is divided into three) of the tape-type diaper, or a stretchable fastening tape (stretchable region) may be provided at the left-right end portion (protruding from the main body portion in the left-right direction). Even when these stretchable regions are used as the test piece T, the value obtained by dividing the first measurement value A1 by the second measurement value A2 is set to be smaller than 1.2. This makes it possible to prevent the fastening tape and the main body portion on the back side from easily stretching when the tape-type diaper is worn, and to prevent the user from getting the impression that the product is too tight.

[0083] <Method of measuring first measurement value A1 and second measurement value A2> Next, a method for measuring the first measurement value A1 and the second measurement value A2 will be described. The measurement is performed using a tensile tester (for example, Shimadzu Corporation's Autograph, Model AGS-1kNG, or equivalent). The test environment is a room temperature of 23°C ± 2°C and a humidity of 50% ± 5%.

[0084] (1) First, prepare two diapers 1 immediately after removal from the package. In other words, prepare two diapers 1 each having a test piece T of the same configuration. For example, in FIG. 7A, the entire area of ​​the annularly connected ventral waist portion 20 and dorsal waist portion 30 is the test piece T. Therefore, the vertical width of the test piece T is the vertical length W of the side joint portion SS.

[0085] In FIG. 7B, the upper half region Au of the ventral waist portion 20 and the dorsal waist portion 30 connected in a ring shape is taken as the test piece T. Therefore, the vertical width of the test piece T is W / 2, which is half the vertical length of the side joint portion SS. In this case, a part of the waist portions 20, 30 is cut along the cut line C1 shown in FIG. 2 so as not to affect the stretchability of the lower half of the waist portions 20, 30. The cut line C1 is a line that extends in the left-right direction from the left-right side ends of the waist portions 20, 30 to the side portions of the absorbent main body 10 at the vertical center CL of the waist portions 20, 30.

[0086] As described above, the test piece T refers to a portion including a part or the entire stretchable region of the waistline portions 20, 30. The test piece T is set in the jigs 61, 61 of the tensile tester 60, and the test is performed in a state where portions other than the test piece T (for example, the absorbent body 10 and the lower half of the waistline portions 20, 30) are also connected to the test piece T. For this reason, elastic members that affect the stretchability in the left-right direction other than the waistline elastic members 23, 33 (for example, leg-line elastic members arranged at an angle to the up-down direction along the leg-line openings LH, not shown) are cut in advance.

[0087] (2) Next, the distance between the jigs 61, 62 of the tensile tester 60 is adjusted depending on the size of the diaper 1. The length from the top end of the upper jig 61 to the bottom end of the lower jig 62 is defined as the jig distance L2. In this embodiment, the initial jig distance L2 (e.g., 140 mm) is set so that the waist portions 20, 30 are stretched by approximately 41% (e.g., 38% to 45%) of the left-right dimension (e.g., L1 = 345 mm) at the maximum stretch of the waist portions 20, 30.

[0088] (3) Next, the portion of the test piece T of the diaper 1 is set in the jigs 61 and 62 of the tensile tester 60. The tensile direction of the tensile tester 60 is aligned with the stretch direction of the test piece T (left and right direction of the diaper 1). If the test piece T is an annular waistline portion 20 or 30, the side joint portion SS is set to be located at the upper end of the upper jig 61 and the lower end of the lower jig 62. If the test piece T is not annular, the test piece T (e.g., one of the ventral waistline portion 20 and the rear waistline portion 30, or the rear waistline portion of a tape-type diaper) is clamped with a clip-type jig, and the entire absorbent article in the developed state is set in the tensile tester. In this case, the center of the jig in the width direction (direction perpendicular to the tensile direction) is aligned with the center of the test piece T in the direction perpendicular to the stretch direction (vertical direction of the diaper 1).

[0089] (4) Next, the test piece T is stretched to 84% of its maximum length (e.g., L2 = 345 x 0.84 = 290 mm) at a speed of 50,000 mm / min, and the force (N) measured when the test piece T is stretched to 84% is obtained. The force is divided by the width (mm) of the test piece T to obtain the first measured value A1 (N / mm).

[0090] Since the tensile tester 60 used in this embodiment does not support a speed of 50,000 mm / min, one of the jigs 62 was pulled manually. Specifically, it was pulled a distance of 150 mm (=290 mm-140 mm) in about 0.18 seconds. When doing it manually, it is not limited to strictly extending at a speed of 50,000 mm / min, and a speed error of about ±10,000 mm / min is allowed. However, it is not limited to pulling the jig 62 manually, and the measurement may be performed using a tensile tester that supports high speeds.

[0091] (5) Next, the test piece T (diaper 1) that has been stretched at high speed is removed from the jigs 61, 62, and the other test piece T (diaper 1) is similarly set in the jigs 61, 62. The test piece T is stretched to a length that is 84% ​​of the maximum stretch (e.g., L2 = 290 mm) at a speed of 500 mm / min. The test piece T is stretched mechanically using the tensile tester 60, not manually. Then, the force (N) measured when the test piece T is stretched to 84% is obtained. The force divided by the width (mm) of the test piece T is defined as the second measured value A2 (N / mm).

[0092] (6) Finally, calculate the value obtained by dividing the first measurement value A1 by the second measurement value A2 (rounded off to two decimal places) and check whether the value is smaller than 1.2. Note that, since the test pieces T of the same width are elongated at different speeds, it is not necessary to convert the force per unit width (N / mm). In other words, the force (N) obtained from the tensile tester 60 during high-speed elongation divided by the force (N) obtained from the tensile tester 60 during low-speed elongation may be used as the value obtained by dividing the first measurement value A1 by the second measurement value A2.

[0093] <Method of measuring the third measurement value A3 and the fourth measurement value A4> Next, a method for measuring the third measurement value A3 and the fourth measurement value A4 will be described. (1) The test piece T is set in the jigs 61 and 62, and the test piece T is elongated to 84% of its maximum elongation length at a speed of 50,000 mm / min. This is the same as the measurement method described above.

[0094] (2) After that, the test piece T is contracted so that the length of the test piece T becomes 66% of the maximum elongation length (e.g., L2 = 228 mm = 345 × 0.66) when 15 seconds have elapsed from the start of the test. The test piece T is contracted at a high speed (50,000 mm / min) in the same manner as when it was extended. If the tensile tester 60 does not support high speed, the jig 62 is moved manually. Specifically, the test piece is moved 62 mm (= 290 - 228) in about 0.07 seconds, but when performed manually, it is not limited to being contracted strictly at a speed of 50,000 mm / min. Then, the force (N) measured when the test piece T contracts to 66% of the maximum elongation length is obtained. The value obtained by dividing the force by the width (mm) of the test piece T is taken as the third measured value A3 (N / mm).

[0095] (3) After that, the test piece T is maintained in an elongated state at 66% of its maximum elongation. The force (N) measured 600 seconds after the start of the test (i.e., 585 seconds after the test piece T contracted from 84% to 66% of its maximum length) is obtained. The force is divided by the width (mm) of the test piece T to obtain the fourth measured value A4 (N / mm).

[0096] (4) Then, calculate the value obtained by dividing the fourth measurement value A4 by the third measurement value A3 (rounding off to two decimal places), and confirm whether the value is 0.95 or more. Note that since this is a change in the measurement value of the test piece T of the same width, it is not necessary to convert it to force per unit width (N / mm). In other words, the value obtained by dividing the force (N) obtained from the tensile tester 60 585 seconds after shrinkage by the force (N) obtained from the tensile tester 60 immediately after shrinkage may be used as the value obtained by dividing the fourth measurement value A4 by the third measurement value A3.

[0097] <Example> The diapers of the comparative example and the example were actually manufactured, and the above measurements were carried out. Both the diapers of the comparative example and the example were pants-type diapers having the configurations shown in Figs. 1 to 3. The length L1 in the left-right direction at maximum stretch of the waist-line portions 20, 30 was 345 mm, and the length W in the up-down direction was 127 mm. The stretch ratio of the waist-line elastic members 23, 33 was 2.8 times, and the thickness was 470 dtex. The number of waist-line elastic members 23 in the ventral waist-line portion 20 was 9, and the number of waist-line elastic members 33 in the dorsal waist-line portion 30 was 10.

[0098] In the diaper of the comparative example, hot melt adhesive was applied continuously around the entire circumference and in the longitudinal direction of the waist-surrounding elastic members 23, 33, and the waist-surrounding elastic members 23, 33 were attached in a stretched state between the skin-side sheets 21, 22 and the non-skin-side sheets 31, 32.

[0099] In the diaper of the embodiment, as shown in Fig. 4 to Fig. 6C, waist elastic members 23, 33 were attached between the skin side sheets 21, 22 and the non-skin side sheets 31, 32 by using a welded portion 50. Three types of welded portion rows Ra to Rc were formed in the waist portions 20, 30 at intervals of 5 mm in the left-right direction. As shown in Fig. 6A etc., in the welded portion rows Ra to Rc, the welded portions 50 were formed continuously in the up-down direction in the areas other than the areas where the waist elastic members 23, 33 were located.

[0100] In the first welded portion row Ra (FIG. 6A), the welded portions 50 each having a left-right length Wa of 2.5 mm are arranged in a straight line in the vertical direction. The vertical length GH of the region in which the waistline elastic members 23, 33 are located is 0.28 mm. As shown in FIG. 4, two first welded portion rows Ra were formed immediately inside the side joint portions SS and immediately outside the absorbent main body 10.

[0101] In the second welded portion row Rb (FIG. 6B), the welded portions 50, each having a left-right length Wb of 0.5 mm, are arranged vertically while meandering slightly in the left-right direction. The vertical length GH of the region in which the waistline elastic members 23, 33 are located is 0.28 mm, the same as the first welded portion row Ra. The second welded portion row Rb is formed outside the absorbent main body 10 and between the first welded portion rows Ra.

[0102] In the third welded portion row Rc (FIG. 6C), the welded portions 50 each having a left-right length Wc of 0.5 mm are arranged in a straight line in the vertical direction. The vertical length GHc of the region in which the waistline elastic members 23, 33 are located is wide, at 0.6 mm. The third welded portion row Rc is formed in the region overlapping with the absorbent main body 10.

[0103] In the rows of welded parts Ra to Rc shown in Figures 6A to 6C, the multiple welded parts 50 are arranged vertically at intervals. However, in the diaper produced as the example, the welded parts 50 are continuous in the vertical direction except in the spaces where the waist elastic members 23, 33 are located.

[0104] The results of dividing the first measurement value A1 by the second measurement value A2 for the diapers of the comparative example and the embodiment are shown in Figs. 8A and 8B. Fig. 8A shows the results when the entire area of ​​the annular waist portions 20, 30 was used as the test piece T. For the diaper of the comparative example, the force (a1) measured during high-speed elongation was 14.739 (N), and the force (a2) measured during low-speed elongation was 10.761 (N). Therefore, the value (a1 / a2) obtained by dividing the first measurement value A1 by the second measurement value A2 was 1.37, which was greater than 1.2.

[0105] On the other hand, in the diaper of the embodiment, the force (a1) measured during high speed elongation was 10.133 (N), and the force (a2) measured during low speed elongation was 9.260 (N). Therefore, the value (a1 / a2) obtained by dividing the first measurement value A1 by the second measurement value A2 was 1.09, which was smaller than 1.2.

[0106] 8B shows the results when the upper half of the annular waist portions 20, 30 was used as the test piece T. In the comparative diaper, the force (a1) measured during high-speed elongation was 6.863 (N), and the force (a2) measured during low-speed elongation was 5.281 (N). Therefore, the value (a1 / a2) obtained by dividing the first measurement value A1 by the second measurement value A2 was 1.30, which was greater than 1.2.

[0107] On the other hand, in the diaper of the embodiment, the force (a1) measured during high speed elongation was 5.516 (N), and the force (a2) measured during low speed elongation was 4.852 (N). Therefore, the value (a1 / a2) obtained by dividing the first measurement value A1 by the second measurement value A2 was 1.14, which was smaller than 1.2.

[0108] From the above results, it was found that in the embodiment in which the waist elastic members 23, 33 are attached by the welded portion 50, the stress (A1, a1) during high-speed elongation is suppressed and the difference with the stress (A2, a2) during low-speed elongation is reduced, compared to the comparative example in which the waist elastic members 23, 33 are attached by a large amount of adhesive. Therefore, the waist portions 20, 30 can be easily and quickly expanded when the diaper is put on, and the impression that the product is too tight can be reduced.

[0109] Furthermore, subjects (21 people) were asked to evaluate the wearability of the diapers of the Comparative Example and the Example. As a result, 69% of the subjects evaluated that the Example had very good or slightly good waist stretch compared to the Comparative Example diaper. 71% of the subjects evaluated that the Example was very easy to put on or slightly easy to put on compared to the Comparative Example diaper. Also, 69% of the subjects evaluated that the Example did not constrict the body very much or slightly did not constrict the body compared to the Comparative Example diaper. From the above results, it was found that diapers with a value obtained by dividing the first measurement value A1 by the second measurement value A2 smaller than 1.2 had good waist stretch, were easy to put on, and gave the impression of not constricting the body.

[0110] 9A and 9B show the results of dividing the fourth measurement value A4 by the third measurement value A3 for the diapers of the comparative example and the embodiment. FIG. 9A shows the results when the entire area of ​​the annular waistline portion 20, 30 is used as the test piece T. In the diaper of the comparative example, the measurement value immediately after contraction to 66% was 4.482 N, and the measurement value 600 seconds after the start of the test was 4.192 N. Therefore, the value (a4 / a3) obtained by dividing the fourth measurement value A4 by the third measurement value A3 was 0.94, which was smaller than 0.95. On the other hand, in the diaper of the embodiment, the measurement value immediately after contraction was 3.248 N, and the measurement value 600 seconds after contraction was 3.082 N. Therefore, the value (a4 / a3) obtained by dividing the fourth measurement value A4 by the third measurement value A3 was 0.95.

[0111] 9B shows the results when the upper half of the waist portions 20, 30 was used as the test piece T. In the diaper 1 of the comparative example, the measurement immediately after contraction was 2.228 N, and the measurement after 600 seconds was 2.068 N, and the value obtained by dividing the fourth measurement value A4 by the third measurement value A3 (a4 / a3) was 0.93, which was smaller than 0.95. On the other hand, in the diaper of the embodiment, the measurement immediately after contraction was 1.845 N, and the measurement after 600 seconds was 1.747 N, and the value obtained by dividing the fourth measurement value A4 by the third measurement value A3 (a4 / a3) was 0.95.

[0112] From the above results, it was found that in the embodiment in which the waist elastic members 23, 33 were attached at the welded portion 50, the stress (A3, a3) immediately after contraction to 66% was low, and the difference with the stress (A4, a4) when the contraction stabilized was also small. Therefore, in the diaper of the embodiment, it is possible to prevent the wearer from feeling a strong sense of tightness immediately after the waist portions 20, 30 are greatly expanded in order to put on the diaper and then contract to fit the wearer. In addition, the change in the feeling of tightness (fit) during wear is small, and the discomfort during wear can be reduced.

[0113] <Other features> It is preferable that at least one of the ventral waist portion 20 and the back waist portion 30 is as follows. As shown in Fig. 4, when a plurality of waist elastic members 23, 33 are arranged at intervals in the vertical direction in the waist portions 20, 30, it is preferable that the positions of all the waist elastic members 23, 33 overlapping with the side joint portions SS in the vertical direction are restricted by the welded portions 50. In other words, it is preferable that the vertical positions of all the waist elastic members 23, 33 provided in the waist portions 20, 30 are restricted with respect to the pair of sheets (21 and 22, 31 and 32) by being sandwiched between two vertically adjacent welded portions 50 in a state in which they are contracted in the left-right direction.

[0114] This allows the amount of adhesive applied to the waist portions 20, 30 to be reduced, and the adhesive is less likely to be affected by hardening even when the waist portions 20, 30 are stretched at high speed. This reduces the stress during high-speed stretching and reduces the difference in stress from low-speed stretching. This allows the waist portions 20, 30 to be easily stretched quickly, and is comfortable to wear, preventing the user from getting the impression that the product is too tight.

[0115] However, without being limited to the above, some of the waistline elastic members 23, 33 (preferably four or less waistline elastic members 23, 33) of the waistline portions 20, 30 may be attached to the sheet not by the welded portion 50 but by an adhesive.

[0116] 4, between the pair of side joints SS, the position of the waistline elastic members 23, 33 may be restricted over the entire left-right area by the welded portion 50. In this case, the amount of adhesive applied to the waistline portions 20, 30 can be reduced, the stress during high-speed elongation can be suppressed, and the difference in stress with respect to low-speed elongation can be reduced. However, this is not limited to the above, and the position of the waistline elastic members 23 in the left-right direction may be restricted in part by the welded portion 50, and another part may be attached to the sheet with an adhesive.

[0117] When the diaper 1 is worn, the left and right ends of the waist portions 20, 30 are stretched and pulled up, etc. Therefore, the waist elastic members 23, 33 are more likely to break and come off at the left and right ends of the diaper 1 than at the center portion. Furthermore, in the case of a pants-type diaper 1, the waist elastic members 23, 33 may be cut when the side joint portions SS are formed.

[0118] 6A to 6C, the waist portion 20, 30 has a plurality of welded portion pairs 51, which are two welded portions 50 adjacent to each other in the vertical direction and positioned with the waist elastic member 23, 33 between them. The plurality of welded portion pairs 51 may include a welded portion pair (first welded portion pair) having a small vertical length GH between the welded portions 50, specifically, the welded portion pair 51a of the first welded portion row Ra and the welded portion pair 51b of the second welded portion row Rb, and a welded portion pair (second welded portion pair) having a large vertical length GHc between the welded portions 50, specifically, the welded portion pair 51c of the third welded portion row Rc, located closer to the center in the horizontal direction. Note that it is sufficient for the waist portion 20, 30 to have at least one set of the first welded portion pair and the second welded portion pair. Furthermore, the second welded portion pair (the welded portion pair 51c in the third welded portion row Rc) does not have to be in contact with the waistline elastic members 23, 33.

[0119] By doing so, the waist elastic members 23, 33 can be firmly sandwiched by the welded portion pairs 51a of the first welded portion row Ra and the welded portion pairs 51b of the second welded portion row Rb at the left and right ends of the waist portions 20, 30. Therefore, even if the waist elastic members 23, 33 are torn at the side joint portion SS, the torn end portions of the waist elastic members 23, 33 are easily held by the welded portion pairs 51a, 51b in the vicinity. Thus, stretchability is ensured over a wide range in the left and right directions of the waist portions 20, 30.

[0120] On the other hand, in the center of the waistline portions 20, 30 in the left-right direction, the vertical interval GHc of the welded portions 50 is wide, so that the waistline elastic members 23, 33 can be prevented from being cut when the welded portions 50 are formed. Even if the vertical interval GHc of the welded portions 50 is wide, the waistline elastic members 23, 33 can be prevented from being significantly displaced in the vertical direction. In addition, the welded portions 50 can prevent the skin side sheets 21, 31 and the non-skin side sheets 22, 32 from floating. Therefore, the amount of adhesive used in the waistline portions 20, 30 can be reduced compared to when adhesive is used to prevent the sheets from floating. Therefore, the stress during high-speed elongation of the waistline portions 20, 30 is suppressed, and the difference with the stress during low-speed elongation can be reduced, making it easier to quickly expand the waistline portions 20, 30. Furthermore, in the left-right central portion (third welded portion row Rc) of the waist portions 20, 30, the frictional force between the welded portions 50 and the waist elastic members 23, 33 is small, which also makes it easier to expand the waist portions 20, 30.

[0121] The multiple welded portion pairs 51 may include a welded portion pair (third welded portion pair) having a long length Wa in the left-right direction of the welded portion 50, specifically, a welded portion pair 51a in the first welded portion row Ra, and a welded portion pair (fourth welded portion pair) having a short length Wb, Wc in the left-right direction of the welded portion 50, located closer to the left-right center than the welded portion pair 51a, specifically, a welded portion pair 51b in the second welded portion row Rb and a welded portion pair 51c in the third welded portion row Rc. Note that it is sufficient for the waist portion 20, 30 to have at least one set of the third welded portion pair and the fourth welded portion pair.

[0122] By increasing the length of the welded portion 50 in the left-right direction, the frictional force generated between the welded portion 50 and the waist elastic member 23 is increased, and the waist elastic members 23, 33 can be prevented from coming off from the welded portion pair 51. Therefore, even if the waist elastic members 23, 33 are torn at the side joint portion SS, the torn end portion of the waist elastic members 23, 33 is easily held by the welded portion pair 51a nearby. Therefore, the waist portions 20, 30 are stretchable over a wide range in the left-right direction.

[0123] On the other hand, in the region away from the side joint SS toward the center in the left-right direction, there is no need to unnecessarily constrain the waist elastic members 23, 33 by the welded part pair 51. Therefore, by shortening the lengths Wb, Wc of the welded parts 50, the frictional force between the welded parts 50 and the waist elastic members 23, 33 is reduced. This makes it easier to expand the waist parts 20, 30, and reduces the impression that the product is too tight. In addition, by shortening the left-right length of the highly rigid welded parts 50, the flexibility of the waist parts 20, 30 is also ensured.

[0124] As shown in FIG. 4, the waist elastic members 23, 33 overlapping the absorbent main body 10 may be cut and discontinuous at the center in the left-right direction of the diaper 1. In the region SB where the waist elastic members 23, 33 are discontinuous, the elasticity is hardly exhibited, and the elastic force of the waist elastic members 23, 33 per unit width in the vertical direction is lower than that in the region SA where the waist elastic members 23, 33 are continuous. Therefore, the waist portions 20, 30 can be easily expanded when the diaper 1 is put on. In addition, the absorbent main body 10 can be prevented from being contracted by the waist elastic members 23, 33, the flatness of the absorbent main body 10 (particularly the absorbent core 11) is ensured, and the fit to the wearer is improved.

[0125] Furthermore, when the waist elastic members 23 are cut during the manufacturing process of the diaper 1, the waist elastic members 23 contract and increase in diameter, and are sandwiched between the intermediate welded portions 51. Therefore, when the waist portions 20, 30 are stretched, the cut ends of the waist elastic members 23, 33 in the stretched state are held by the welded portions 51, ensuring stretchability at the continuous portion SA.

[0126] Therefore, as shown in Fig. 4, it is advisable to provide a first welded portion row Ra with a long length of the left-right welded portion 50 at the end on the left-right center side of the region (SA) where stretchability is desired. By doing so, the cut end portion of the waist elastic member 23 cut to form the discontinuous portion of the waist elastic members 23, 33 is firmly held by the first welded portion row Ra. This ensures the stretchability of the waist portions 20, 30 (continuous portion SA).

[0127] 6A to 6C, the multiple welded parts 50 provided on the waistline parts 20, 30 include first welded parts 50ah, 50bh, 50ch adjacent to a certain waistline elastic member 231 (first elastic member). Also, the multiple welded parts 50al, 50bl, 50cl are located in the vertical center between the waistline elastic member 231 and the vertically adjacent waistline elastic member 232 (second elastic member). In this case, the first welded parts 50ah, 50bh, 50ch adjacent to the waistline elastic members 23, 33 may have stronger weld strength than the second welded parts 50al, 50bl, 50cl.

[0128] This allows the waist elastic members 23, 33 to be firmly sandwiched by the highly rigid first welded parts 50ah, 50bh, and prevents the waist elastic members 23, 33 from slipping out of the welded part pair 51. In addition, the highly rigid first welded part 50ch can firmly restrict the waist elastic members 23, 33 from shifting in position in the up-down direction.

[0129] On the other hand, by weakening the welding strength of the second welded parts 50al, 50bl, 50cl located away from the waist elastic members 23, 33, it is possible to suppress lifting of the skin side sheets 21, 22 and the non-skin side sheets 22, 32 while ensuring the flexibility of the waistline parts 20, 30. Therefore, the amount of adhesive used in the waistline parts 20, 30 can be reduced compared to when adhesive is used to suppress sheet lifting. Therefore, the stress during high-speed elongation of the waistline parts 20, 30 is suppressed, and the difference with the stress during low-speed elongation can be reduced, making it easier to quickly expand the waistline parts 20, 30. The difference in welding strength between the first welded parts 50ah, 50bh, 50ch and the second welded parts 50al, 50bl, 50cl can be visually determined based on the degree of melting of the sheet. Specifically, when the welding strength is strong, the sheet is completely turned into a film at the welded part 50. If the weld strength is weak, the fibers of the nonwoven fabric remain at the welded portion.

[0130] In this embodiment, the welds 50 are arranged vertically at intervals in the weld rows Ra to Rc. Therefore, the first welds 50ah, 50bh, 50ch and the second welds 50al, 50bl, 50cl are arranged discontinuously in the vertical direction. However, this is not limited to this, and the welds 50 may be continuous in the vertical direction in areas other than the areas where the waist elastic members 23, 33 are located, and the first welds 50ah, 50bh, 50ch and the second welds 50al, 50bl, 50cl may be continuous. Also, it is preferable that the second welds 50al, 50bl, 50cl are more numerous than the first welds 50ah, 50bh, 50ch as shown in FIG. 6A and the like, or be longer in the vertical direction (not shown). This can ensure the flexibility of the waist portions 20, 30. For example, a plurality of welds 50 may be arranged vertically at intervals. However, without being limited to the above, the first welded portions 50ah, 50bh, 50ch and the second welded portions 50al, 50bl, 50cl may have the same weld strength.

[0131] Furthermore, as shown in FIG. 5A, when the waist portions 20, 30 (stretchable regions) are stretched in the left-right direction, it is preferable that the vertical length GH between two welded portions 50 that are adjacent in the vertical direction and sandwich the waist elastic members 23, 33 is greater than the vertical length d1 of the waist elastic members 23, 33 (GH>d1).

[0132] As the waist parts 20, 30 stretch in the left-right direction, the waist elastic members 23, 33 become thinner and the length in the up-down direction becomes shorter (from d2 to d1). At this time, the waist elastic members 23, 33 become thinner than the gap GH of the welded parts 50, so that the frictional force generated between them can be reduced. This makes it easier to expand the waist parts 20, 30, and prevents the user from getting the impression that the product is too tight.

[0133] Although the welded parts 50 have been described above, the shape, number, arrangement, etc. of the welded parts 50 are not limited to those described above. For example, in Fig. 4, the welded part rows Ra to Rc are arranged at regular intervals in the left-right direction, but this is not limited to this. For example, near the side joint parts SS where the waist elastic members 23, 33 are easily torn, or near the sides of the absorbent main body 10 where the waist elastic members 23, 33 are cut during manufacturing, the intervals in the left-right direction of the welded part rows Ra to Rc may be narrower than in other regions. By doing so, the cut ends of the waist elastic members 23, 33 are firmly gripped by the welded part rows Ra to Rc.

[0134] As shown in Fig. 3, the pants-type diaper 1 includes an absorbent main body 10 and an outer body (ventral waist portion 20, rear waist portion 30, extension portion 30E) on the non-skin side thereof. When the side joint portion SS of the diaper 1 is separated and the diaper 1 is laid out, the waist portion 20, 30 (stretchable region) preferably has a region 25, 35 in which the number of layers of the outer body sheets is two, that is, a pair of sheets (skin side sheets 21, 22 and non-skin side sheets 22, 32) sandwiching the waist elastic members 23, 33 therebetween. In Fig. 3, the two-layer region 25, 35 is formed between the upper end of the absorbent main body 10 and the lower ends of the folded-back portions 24, 34 of the non-skin side sheets 22, 32.

[0135] Thus, the presence of regions 25, 35 in which the number of laminated sheets is small can reduce the region in the waistband portions 20, 30 where sheets are laminated and joined with adhesive, and can reduce the amount of adhesive used in the waistband portions 20, 30. Therefore, the stress during high-speed elongation of the waistband portions 20, 30 is suppressed, and the difference with the stress during low-speed elongation can be reduced, making it easier to quickly expand the waistband portions 20, 30.

[0136] 3, at least one of the pair of sheets (non-skin side sheets 22, 32 in this example) sandwiching the waist elastic members 23, 33 has an upper end portion folded downward in the up-down direction to provide folded-back portions 24, 35. In this case, it is preferable that an area where no adhesive is applied is provided between the upper end of the absorbent main body 10 and the lower end of the folded-back portions 25, 35. In this embodiment, the folded-back portions 24, 34 (non-skin side sheets 22, 32) are joined to the skin side surface of the skin side sheets 21, 31 with an adhesive, and the non-skin side surface of the absorbent main body 10 is joined to the waist portions 20, 30 with an adhesive. The areas 25, 35 therebetween are areas where no adhesive is applied.

[0137] In this way, by providing the waist portions 20, 30 with areas where no adhesive is applied, it is possible to reduce the amount of adhesive used in the waist portions 20, 30. Therefore, the stress during high-speed elongation of the waist portions 20, 30 is suppressed, and the difference with the stress during low-speed elongation can be reduced, making it easier to quickly expand the waist portions 20, 30.

[0138] The region where no adhesive is applied includes a region where no adhesive is applied among regions where adhesive is applied in a known pattern (e.g., a spiral pattern, an Ω pattern, etc.). In other words, the region where no adhesive is applied includes a region other than a region where adhesive is applied without gaps (a so-called solidly applied region).

[0139] In addition, as shown in FIG. 2, in the developed state of the diaper 1, the portion 11b of the absorbent core 11 overlapping with the rear waist portion 30 in the thickness direction has a smaller average basis weight (g / m2) of the absorbent core 11 than the portion 11f of the absorbent core 11 overlapping with the ventral waist portion 20 in the thickness direction. 2 ) is preferably low.

[0140] In this case, the rigidity of the absorbent core 11 located in the rear waist portion 30 is reduced, so that the rear waist portion 30 can be easily stretched. Therefore, when the diaper 1 is put on, the rear waist portion 30 can be expanded to a large extent so as to cover the buttocks. On the other hand, by increasing the basis weight of the absorbent core 11 in the ventral waist portion 20 close to the urination area, leakage of excreted liquid can be suppressed.

[0141] 10A and 10B are explanatory diagrams of the waistline elastic members 23, 33. It is preferable that a lubricant is applied to at least one of the surfaces of the waistline elastic members 23, 33 and the inner surfaces of the pair of sheets 21, 22, 31, 32 that sandwich the waistline elastic members 23, 33. In Fig. 10A, a lubricant 70 is applied to the waistline elastic members 23, 33. Although not shown, a lubricant may be applied to the non-skin side surfaces of the skin side sheets 21, 31 and the skin side surfaces of the non-skin side sheets 22, 32.

[0142] This reduces the frictional force between the waistline elastic members 23, 33 and the skin side sheets 21, 22 and the non-skin side sheets 31, 32. This makes it easier to expand the waistline portions 20, 30, preventing the user from getting the impression that the product is too tight.

[0143] Furthermore, even if the protruding patterns forming the welded portions 50 and the side seams SS step on the waist elastic members 23, 33 during the manufacturing process of the diaper 1, the lubricant 70 makes it easy for the waist elastic members 23, 33 to slide. This makes it easy for the waist elastic members 23, 33 to be pushed out of the protruding patterns, thereby preventing the waist elastic members 23, 33 from being cut.

[0144] An example of the lubricant is an oil. The type of oil is not particularly limited, and may be applied to the elastic fibers 23A constituting the waist elastic members 23, 33 for the purpose of preventing adhesion, improving processability, etc. Specifically, an oil containing dimethylpolysiloxane, modified polysiloxane in which a portion of the methyl group is replaced with another alkyl group, phenyl group, amino group, etc., mineral oil, etc. as a main component can be used.

[0145] 10A, the waist elastic members 23, 33 are preferably thread-like elastic members each made up of a plurality of elastic fibers 23A. In this way, even if some of the elastic fibers 23A are cut during the process of forming the side joints SS, the remaining elastic fibers 23A are connected, preventing the waist elastic members 23, 33 from being cut. This makes it possible to prevent the waist elastic members 23, 33 from coming off the welded portion pair 51, and ensures the stretchability of the waist portions 20, 30.

[0146] Furthermore, since the elastic members 23A are made up of a plurality of elastic fibers 23A, voids S are easily formed between the elastic fibers 23A. Therefore, even if the waistline elastic members 23, 33 are compressed into the convex patterns forming the side joints SS and the welded parts 50, the voids S are compressed to create an escape space (because the convex patterns are not reached), and therefore, cutting of the waistline elastic members 23, 33 can be suppressed.

[0147] In addition, since the elastic members 23, 33 are made of a plurality of elastic fibers 23A, the thickness of the elastic members 23, 33 tends to vary depending on how the elastic fibers 23A are assembled. For example, as shown in Fig. 10A, the elastic members 23, 33 have a large diameter portion 23B having an outer diameter of a first outer diameter d23B and a small diameter portion 23C (groove portion) having an outer diameter d23C smaller than the first outer diameter d23B. In this way, when the large diameter portion (23B) of the elastic members 23, 33 is positioned between the pair of welded portions 51, the large diameter portion is tightly sandwiched between the pair of welded portions 51, and the elastic members 23, 33 can be prevented from coming off from the pair of welded portions 51.

[0148] Moreover, it is preferable that the waist elastic members 23, 33 are arranged in a twisted state between the pair of sheets 21, 22, 31, 31. This increases the surface area of ​​the waist elastic members 23, 33, and increases the frictional force with the sheets (easier to be entangled with the fibers of the sheets), which can prevent the waist elastic members 23 from coming off the welded portion pair 50. Thus, the stretchability of the waist portions 20, 30 is ensured.

[0149] Moreover, it is preferable that the waist elastic members 23, 33 are transparent and do not contain pigments (such as white titanium oxide). This makes the surface of the waist elastic member 23 smooth, and reduces friction between the skin side sheets 21, 31 and the non-skin side sheets 22, 32 and the waist elastic members 23, 33. This makes it easier to expand the waist portions 20, 30.

[0150] The above-mentioned embodiment is for the purpose of facilitating understanding of the present invention, and is not intended to limit the present invention. The present invention can be modified and improved without departing from the spirit of the present invention, and it goes without saying that the present invention includes equivalents thereof. [Explanation of symbols]

[0151] 1 Diapers (absorbent articles), 10 absorbent body, 11 absorbent core, 12 top sheet, 13 back sheet, 14 exterior sheet, 15 leg elastic member, 16 Leak-proof wall elastic member, 20 ventral girth, 21 skin side sheet (sheet), 22 non-skin side sheet (sheet), 23 waist elastic member (elastic member, first elastic member), 23A elastic fiber, 24 folded portion, 30 back waist portion, 30E extension portion, 31 skin side sheet (sheet), 32 non-skin side sheet (sheet), 33 waist elastic member (elastic member), 34 folded portion, SS side joint, 50 welds, 60 tensile testing machine, 61 fixture, 62 fixture, 70 Lubricants, T test piece,

Claims

1. having a vertical direction and a horizontal direction that intersect with each other, The absorbent article has an absorbent core, a ventral waistband portion, and a dorsal waistband portion, An absorbent article having a stretchable region in which an elastic member stretchable in the left-right direction is arranged in at least one of the ventral waistline portion and the back waistline portion, At least a portion of the elastic region is used as a test specimen, The force measured when the test piece is stretched in the left-right direction at a rate of 50,000 mm / min to a length that is 84% ​​of the maximum stretched length is divided by the width of the test piece in the up-down direction, and the result is defined as a first measurement value; The test piece is stretched in the left-right direction at a rate of 500 mm / min to a length that is 84% ​​of the maximum stretched length, and the force measured when the stretched test piece is stretched is divided by the width, and the result is defined as a second measurement value. the first measurement value divided by the second measurement value is less than 1.2; a pants-type absorbent article in which the ventral waist portion and the back waist portion are joined by a pair of side joining portions at both sides in the left-right direction, The test piece is a portion of the ventral waistline portion and the back waistline portion joined in an annular shape by the side joint portion, the portion being above the center of the side joint portion in the up-down direction, an absorbent body including the absorbent core; At least one of the ventral waist portion and the dorsal waist portion, an upper end portion of at least one of the pair of sheets sandwiching the elastic member therebetween is provided with a folded portion folded downward in the up-down direction; The folded portion is joined to the skin side of the other sheet of the pair of sheets with an adhesive at the upper portion. An absorbent article characterized by:

2. The absorbent article according to claim 1, In a test in which the test piece was stretched at a rate of 50,000 mm / min to a length that was 84% ​​of the maximum stretch, and then contracted to a length that was 66% of the maximum stretch after 15 seconds had elapsed from the start of stretching, The force measured when the test piece is contracted to a length of 66% of the maximum elongation is divided by the width, and the result is defined as a third measurement value. The force measured when 585 seconds have passed since the test piece was contracted to a length of 66% of the maximum elongation was divided by the width, and the result was defined as a fourth measurement value. An absorbent article characterized in that the value obtained by dividing the fourth measurement value by the third measurement value is 0.95 or more.

3. The absorbent article according to claim 1 or 2, In the stretchable region, the elastic member is disposed between a pair of sheets joined by a plurality of welded portions, An absorbent article characterized in that, when contracted in the left-right direction, the elastic member is sandwiched between two adjacent welded portions in the vertical direction, thereby regulating its vertical position relative to the pair of sheets.

4. An absorbent article according to claim 3, At least one of the ventral waist portion and the dorsal waist portion, A plurality of the elastic members are arranged at intervals in the vertical direction, An absorbent article characterized in that all of the elastic members that overlap with the side joint portions in the vertical direction are sandwiched between two of the welded portions adjacent to each other in the vertical direction when contracted in the left-right direction, thereby regulating the vertical position relative to the pair of sheets.

5. An absorbent article according to claim 3, the plurality of welded portions include a plurality of pairs of welded portions that are adjacent to each other in the vertical direction and are positioned with the elastic member between them, the plurality of pairs of welded portions include a first pair of welded portions and a second pair of welded portions located closer to the center in the left-right direction than the first pair of welded portions, An absorbent article, characterized in that the second pair of welded portions has a greater length in the vertical direction between the welded portions sandwiching the elastic member than the first pair of welded portions.

6. An absorbent article according to claim 3, the plurality of welded portions include a plurality of pairs of welded portions that are adjacent to each other in the vertical direction and are positioned with the elastic member between them, the plurality of welded portion pairs include a third welded portion pair and a fourth welded portion pair located closer to the center in the left-right direction than the third welded portion pair, An absorbent article, wherein the fourth pair of welded portions has a smaller length in the left-right direction than the third pair of welded portions.

7. An absorbent article according to claim 3, The stretchable region has a first elastic member and a second elastic member adjacent to each other with a gap in the up-down direction, The plurality of welded portions are a first welded portion adjacent to the first elastic member; a second welded portion located at a center portion in the up-down direction between the first elastic member and the second elastic member, An absorbent article, wherein the first welded portion has a stronger weld strength than the second welded portion.

8. An absorbent article according to claim 3, When the stretchable region is stretched in the left-right direction, An absorbent article characterized in that the vertical length between two of the welded portions that are adjacent in the vertical direction and sandwich the elastic member is greater than the vertical length of the elastic member.

9. The absorbent article according to claim 1 or 2, Equipped with exterior body, In the unfolded state of the absorbent article, The elastic region has a region in which the number of laminated sheets in the exterior body is two, that is, a pair of sheets sandwiching the elastic member therebetween.

10. The absorbent article according to claim 1 or 2, An absorbent article, characterized in that an area where no adhesive is applied is provided between the upper end of the absorbent main body and the lower end of the folded-back portion.

11. The absorbent article according to claim 1 or 2, An absorbent article characterized in that a lubricant is applied to at least one of the surface of the elastic member and the inner surfaces of the pair of sheets sandwiching the elastic member.

12. The absorbent article according to claim 1 or 2, An absorbent article characterized in that the value obtained by dividing the first measurement value by the second measurement value when the dorsal waist portion is used as the test specimen is smaller than the value obtained by dividing the first measurement value by the second measurement value when the ventral waist portion is used as the test specimen.

13. The absorbent article according to claim 1 or 2, An absorbent article characterized in that the value obtained by dividing the first measurement value by the second measurement value when the ventral waist portion is used as the test specimen is smaller than the value obtained by dividing the first measurement value by the second measurement value when the dorsal waist portion is used as the test specimen.

14. The absorbent article according to claim 1 or 2, An absorbent article characterized in that, when the absorbent article is in an unfolded state, the portion of the absorbent core that overlaps with the dorsal waistband in its thickness direction has a lower average basis weight than the portion of the absorbent core that overlaps with the ventral waistband in its thickness direction.

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