Absorbent article

Abstract

An absorbent article having a stretchable region in which elastic members (23, 33) capable of stretching in the left-right direction are disposed in at least one of a stomach-side waist-encircling section (20) and a back-side waist-encircling section (30), said absorbent article being characterized in that: at least a part of the stretchable region is used as a test piece; a first measured value is a value obtained by dividing a force measured when the test piece is elongated in the left-right direction at a speed of 50000 mm / min to a length of 84% at the maximum elongation by a width of the test piece in the up-down direction. A value obtained by dividing a force measured when the test piece is elongated in the left-right direction at a speed of 500 mm / min to a length of 84% of the maximum elongation by the width is defined as a second measured value, and a value obtained by dividing the first measured value by the second measured value is less than 1.2.

Description

Technical Field

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

[0002] Patent document 1 discloses a stretch sheet as follows: in the stress-elongation relationship obtained by stretching the stretch sheet to 2 times at 300 mm / min using a tensile tester and then shrinking it, when the stress at 1.8 times the elongation of the second cycle is set as A and the stress at 1.8 times the shrinkage of the second cycle is set as B, the B / A value of the stretch sheet is 0.83 or more and 0.90 or less. When the stretch sheet is used for the outer body of an absorbent article, A is used as a reference for the ease of expansion of the absorbent article, and B is used as a reference for the fit of the absorbent article. The closer the value of B / A is to 1, the easier it is to wear, and the tightness when wearing will be reduced.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2020-199248 Summary of the invention

[0006] Problems to be solved by the invention

[0007] However, when the user actually expands the outer body (waistline) of the absorbent article to wear the absorbent article, it expands at a much faster speed than the extension speed (300 mm / min) described in Patent Document 1. Therefore, the deviation between the value of A and the ease of expansion of the absorbent article when worn may be large.

[0008] On the other hand, when the absorbent article is worn, the outer body expands relatively slowly due to the wearer's breathing and other movements. Therefore, not only the stress B during contraction as described in Patent Document 1, but also the stretching stress during the slow stretching of the outer body can easily affect the tightening feeling felt by the wearer.

[0009] In absorbent articles, the difference between the ease of expansion (ease of stretching) of the waistline when worn and the ease of expansion (ease of stretching) of the waistline during wear is large, and the user may feel that it is difficult to expand the waistline when wearing. In this case, the user may have the impression that the product is more tightened than the fit during wear.

[0010] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to reduce the difference in the ease of stretching of the waistline portion between when the wearer wears the absorbent article and during the wearer wears the absorbent article, thereby preventing the user from having the impression that the absorbent article is a product with strong tightening.

[0011] Means for solving problems

[0012] The main technical solution for achieving the above-mentioned purpose is an absorbent article having mutually intersecting up and down directions and left and right directions, the absorbent article having an absorbent core, a ventral waistline portion and a dorsal waistline portion, at least one of the ventral waistline portion and the dorsal waistline portion having a stretch region, the stretch region being provided with an elastic member that can stretch along the left and right directions, characterized in that at least a portion of the stretch region is used as a test piece, a value obtained by dividing a force measured when the test piece is stretched at a speed of 50,000 mm / min in the left and right directions to a length of 84% of the maximum stretch by a width of the test piece in the up and down directions is set as a first measured value, a value obtained by dividing a force measured when the test piece is stretched at a speed of 500 mm / min in the left and right directions to a length of 84% of the maximum stretch by the width is set as a second measured value, and a value obtained by dividing the first measured value by the second measured value is less than 1.2.

[0013] Other features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0014] Effects of the Invention

[0015] According to the present invention, the difference in the ease of stretching of the waistline portion between when the absorbent article is worn and during the wear can be reduced, and the user can be prevented from having the impression that the absorbent article is a product with strong tightening. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic perspective view of the underpants type disposable diaper 1.

[0017] Figure 2 This is a schematic plan view of the diaper 1 in the unfolded and stretched state as viewed from the skin side of the wearer.

[0018] Figure 3 yes Figure 2 Schematic cross-sectional view at AA in FIG.

[0019] Figure 4 It is an explanatory diagram of the welded portion rows Ra, Rb, and Rc provided in the abdominal waistline portion 20.

[0020] Figure 5A and Figure 5B This is an explanatory diagram of the attachment function of the waist elastic member 23.

[0021] Figure 6A to Figure 6C This is a partially enlarged view of the welded portion rows Ra, Rb, and Rc.

[0022] Fig. 7A and Figure 7BIt is an explanatory diagram of the tensile test of the waistline parts 20 and 30.

[0023] FIG. 8 is a graph showing the results of a tensile test.

[0024] FIG. 9 is a graph showing the results of a tensile test.

[0025] Fig. 10A and Fig. 10B It is an explanatory diagram of the waist elastic member 23. DETAILED DESCRIPTION

[0026] At least the following matters will become clear from the description of this specification and the accompanying drawings.

[0027] Form 1 is an absorbent article having mutually intersecting up-down directions and left-right directions, the absorbent article having an absorbent core, a ventral waistline portion and a dorsal waistline portion, at least one of the ventral waistline portion and the dorsal waistline portion having a stretch region, the stretch region being provided with an elastic member that can stretch in the left-right direction, characterized in that at least a portion of the stretch region is used as a test piece, a value obtained by dividing a force measured when the test piece is stretched in the left-right direction to 84% of its length at maximum stretch at a speed of 50,000 mm / min by a width of the test piece in the up-down direction is set as a first measured value, a value obtained by dividing a force measured when the test piece is stretched in the left-right direction to 84% of its length at maximum stretch at a speed of 500 mm / min by the width is set as a second measured value, and a value obtained by dividing the first measured value by the second measured value is less than 1.2.

[0028] According to aspect 1, compared with a case where the value obtained by dividing the first measured value by the second measured value is 1.2 or more, the first measured value during high-speed extension can be suppressed and the difference from the second measured value during low-speed extension can be reduced.

[0029] Therefore, the waistline can be easily expanded (easily stretched) when worn, and the difference in fit (tightening feeling) during wearing can be reduced. Therefore, the user can be prevented from having the impression that the absorbent article is a product with strong tightening.

[0030] According to the absorbent article described in Form 1, Form 2 is characterized in that, in a test in which the test piece is stretched to 84% of the length of the maximum stretch at a speed of 50,000 mm / min and then contracted to 66% of the length of the maximum stretch after 15 seconds from the start of the stretching, a value obtained by dividing the force measured when the test piece is contracted to 66% of the length of the maximum stretch by the width is set as a third measurement value, and a value obtained by dividing the force measured 585 seconds after the test piece is contracted to 66% of the length of the maximum stretch by the width is set as a fourth measurement value, and the value obtained by dividing the fourth measurement value by the third measurement value is greater than 0.95.

[0031] According to the second aspect, compared with the case where the value obtained by dividing the fourth measured value by the third measured value is less than 0.95, the third measured value when the waistline portion is greatly stretched and then contracted can be suppressed, and the difference with the fourth measured value after the contraction is stabilized can be reduced. Therefore, the feeling of tightening when the waistline portion contracts to match the wearer when worn (i.e., immediately after wearing) can be suppressed. On the contrary, even if the stretched state continues to match the wearer, the feeling of fitting can be maintained.

[0032] According to the absorbent article described in form 1 or 2, form 3 is characterized in that the absorbent article is a shorts-type absorbent article in which the ventral waistline portion and the dorsal waistline portion are joined at both sides in the left-right direction by a pair of side joining portions,

[0033] The test piece is a portion of the ventral waistline portion and the dorsal waistline portion that are joined into a ring shape by the side joining portion and is located above the center of the side joining portion in the vertical direction.

[0034] According to form 3, the upper part of the waistline tends to affect the ease of expansion and the tightening feeling of the waistline when worn. Therefore, in the upper part of the waistline, if the value obtained by dividing the first measured value by the second measured value is 1.2 or less, or the value obtained by dividing the fourth measured value by the third measured value is 0.95 or more, the waistline is more likely to expand and the tightening feeling immediately after wearing can be further reduced.

[0035] According to the absorbent article described in any one of forms 1 to 3, form 4 is characterized in that, in the stretch region, the elastic member is arranged between a pair of sheets joined by a plurality of welded portions, and the elastic member is sandwiched between two adjacent welded portions in the up-down direction in a state contracted along the left-right direction, thereby limiting the position in the up-down direction relative to the pair of sheets.

[0036] According to aspect 4, the amount of adhesive used in the waistline portion can be reduced. Therefore, when the waistline portion is stretched at a high speed, the influence of the hardness of the adhesive can be reduced, the first measured value can be suppressed, and the difference from the second measured value can be reduced.

[0037] According to the absorbent article described in Form 4, Form 5 is characterized in that the absorbent article is a shorts-type absorbent article in which the ventral waist portion and the dorsal waist portion are joined by a pair of side joints on both sides in the left-right direction, and in at least one of the ventral waist portion and the dorsal waist portion, a plurality of elastic members are arranged at intervals in the up-down direction, and all of the elastic members overlapping with the side joints in the up-down direction are sandwiched between two adjacent fused portions in the up-down direction in a state contracted along the left-right direction, thereby limiting the position in the up-down direction relative to the pair of sheets.

[0038] According to aspect 5, the amount of adhesive used in the waistline portion can be reduced. Therefore, when the waistline portion is stretched at high speed, the influence of the hardness of the adhesive can be reduced, the first measured value can be suppressed, and the difference from the second measured value can be reduced.

[0039] According to the absorbent article described in form 4 or 5, form 6 is characterized in that the multiple welded parts have multiple welded part pairs, and the welded part pairs are located adjacent to each other in the up and down directions and sandwich the elastic member. The multiple welded part pairs have a first welded part pair and a second welded part pair located closer to the center side in the left and right direction than the first welded part pair. Compared with the first welded part pair, in the second welded part pair, the length in the up and down direction between the welded parts sandwiching the elastic member is larger.

[0040] According to the sixth aspect, the elastic member can be prevented from falling off from the first welded portion pair, and stretchability can be ensured over a wide range in the left-right direction of the waist portion. The second welded portion pair can be used to restrict the position of the elastic member in the up-down direction, and the floating of the sheet can be prevented. Therefore, compared with the case where the floating of the sheet is prevented by using an adhesive, the amount of adhesive used in the waist portion can be reduced, the first measured value can be suppressed, and the difference with the second measured value can be reduced.

[0041] According to the absorbent article described in any one of forms 4 to 6, form 7 is characterized in that the multiple welded parts have multiple welded part pairs, and the welded part pairs are located adjacent to each other in the up and down directions and sandwich the elastic member. The multiple welded part pairs have a third welded part pair and a fourth welded part pair located closer to the center side in the left and right direction than the third welded part pair. Compared with the third welded part pair, in the fourth welded part pair, the length of the welded part in the left and right direction is smaller.

[0042] According to the seventh aspect, the elastic member can be prevented from falling off from the third welded portion pair, and stretchability can be ensured over a wide range in the left-right direction of the waist portion. The fourth welded portion pair can be used to restrict the position of the elastic member, and the friction between the elastic member and the welded portion can be reduced, making it easier to expand the waist portion. Therefore, it is possible to prevent users from having the impression that the product is a strong tightening product.

[0043] According to the absorbent article described in any one of forms 4 to 7, form 8 is characterized in that the stretchable area has a first elastic member and a second elastic member adjacent to each other in the up and down direction with a gap therebetween, and the plurality of welded portions include: a first welded portion, which is adjacent to the first elastic member; and a second welded portion, which is located in the center portion in the up and down direction between the first elastic member and the second elastic member, and the welding strength of the first welded portion is stronger than that of the second welded portion.

[0044] According to the eighth aspect, the position of the elastic member can be firmly restricted by the first welded portion having a high rigidity. The second welded portion having a low rigidity can be used to ensure the flexibility of the waist portion and suppress the floating of the sheet. Therefore, compared with the case where the floating of the sheet is suppressed by the adhesive, the amount of adhesive used in the waist portion can be reduced, the first measured value can be suppressed, and the difference with the second measured value can be reduced.

[0045] According to the absorbent article recorded in any one of forms 4 to 8, form 9 is characterized in that, when the stretch area is stretched in the left-right direction, the length in the up-down direction between the two welded parts adjacent to each other in the up-down direction and sandwiching the elastic member is greater than the length in the up-down direction of the elastic member.

[0046] According to aspect 9, as the waistline shrinks in the left-right direction, the elastic member becomes thinner and the constraint by the welded portion is weakened. Therefore, the waistline is easily expanded, and the user can be prevented from having the impression that the product is tightly tightened.

[0047] According to the absorbent article recorded in any one of forms 1 to 9, form 10 is characterized in that the absorbent article is a shorts-type absorbent article in which the ventral waistline portion and the dorsal waistline portion are joined by a pair of side joints on both sides in the left-right direction, the absorbent article comprises an outer body and an absorbent main body including the absorbent core, and in the unfolded state of the absorbent article, the stretch area has an area in which the number of sheets of the outer body stacked is two layers of a pair of sheets that sandwich the elastic component.

[0048] According to aspect 10, the area where the sheets are laminated and joined with an adhesive can be reduced, and the amount of adhesive used in the waistline portion can be reduced. Therefore, the first measured value can be suppressed and the difference from the second measured value can be reduced.

[0049] According to the absorbent article recorded in any one of forms 1 to 10, form 11 is characterized in that the absorbent article is a shorts-type absorbent article in which the ventral waist portion and the dorsal waist portion are joined by a pair of side joining portions on both sides in the left-right direction, the absorbent article has an absorbent body, the absorbent body includes the absorbent core, and at least one of the ventral waist portion and the dorsal waist portion is provided with a folding portion, in which the upper end portion of at least one of a pair of sheets sandwiching the elastic member is folded back downward in the up-down direction, and an area without adhesive is provided between the upper end of the absorbent body and the lower end of the folding portion.

[0050] According to aspect 11, the amount of adhesive used in the waistline portion can be reduced. Therefore, the first measured value can be suppressed and the difference from the second measured value can be reduced.

[0051] According to any one of aspects 1 to 11, aspect 12 is characterized in that a lubricant is attached to at least one of a surface of the elastic member and inner surfaces of a pair of sheets sandwiching the elastic member.

[0052] According to the twelfth aspect, the frictional force generated between the elastic member and the sheet can be reduced, and the waistline portion can be easily expanded. Therefore, it is possible to prevent the user from having the impression that the product is tightly tightened.

[0053] According to the absorbent article described in any one of forms 1 to 12, form 13 is characterized in that a value obtained by dividing the first measured value by the second measured value when the dorsal waistline portion is used as the test piece is smaller than a value obtained by dividing the first measured value by the second measured value when the ventral waistline portion is used as the test piece.

[0054] According to aspect 13, even at high speed, the back waistline portion can be easily extended, and when the absorbent article is worn, the back waistline portion can be easily expanded greatly so as to cover the buttocks.

[0055] According to the absorbent article described in any one of forms 1 to 12, form 14 is characterized in that a value obtained by dividing the first measured value by the second measured value when the ventral waistline portion is used as the test piece is smaller than a value obtained by dividing the first measured value by the second measured value when the dorsal waistline portion is used as the test piece.

[0056] According to form 14, the ventral waistline portion can be easily stretched even at high speeds. Since the ventral waistline portion can be easily expanded when the absorbent article is worn, the feet (especially the toes) can be prevented from being caught when the wearer's feet pass through the waist opening.

[0057] According to the absorbent article recorded in any one of forms 1 to 13, form 15 is characterized in that the absorbent article is a shorts-type absorbent article in which the ventral waistline portion and the dorsal waistline portion are joined by a pair of side joining portions on both sides in the left-right direction, and when the absorbent article is unfolded, the average unit area weight of the absorbent core is lower at a portion of the absorbent core overlapping with the dorsal waistline portion in the thickness direction thereof than at a portion of the absorbent core overlapping with the ventral waistline portion in the thickness direction thereof.

[0058] According to form 15, the rigidity of the absorbent core can be suppressed at the back waistline, and the back waistline can be easily expanded. Therefore, the back waistline can be easily expanded to a large extent to cover the wearer's buttocks. On the other hand, by increasing the unit area weight of the absorbent core at the ventral waistline near the urination part, leakage can be suppressed.

[0059] ===Implementation Method===

[0060] Hereinafter, as the absorbent article of the present embodiment, a shorts-type disposable diaper for infants and young children is exemplified. However, the absorbent article is not limited to the above-mentioned case, and any absorbent article having a ventral waistline portion and a dorsal waistline portion may be used, for example, a shorts-type diaper for adults, a shorts-type sanitary napkin, a belt-type diaper, etc.

[0061] <<Basic structure of the shorts type disposable diaper 1>>

[0062] Figure 1 It is a schematic perspective view of a pants-type disposable diaper 1 (hereinafter also referred to as a "diaper").

[0063] Figure 2 This is a schematic plan view of the diaper 1 in the unfolded and stretched state as viewed from the skin side of the wearer. Figure 3 yes Figure 2 Schematic cross-sectional view at AA in FIG.

[0064] The diaper 1 has a vertical direction, a horizontal direction, and a front-back direction that intersect each other, and has a waist opening BH and a pair of leg openings LH. In the vertical direction, the waist opening BH side is set as the upper side, and the side that will become the crotch side of the wearer is set as the lower side. In the front-back direction, the side that will become the belly side of the wearer is set as the front side, and the side that will become the back side is set as the back side. In addition, as shown in FIG. Figure 3 As shown, the diaper 1 has a thickness direction of the laminated material, and in the thickness direction, the side in contact with the wearer is referred to as the skin side, and the opposite side is referred to as the non-skin side.

[0065] The diaper 1 includes an absorbent body 10 and a pair of waist parts 20, 30. The pair of waist parts 20, 30 are joined to the non-skin side of the absorbent body 10 by adhesive or the like. The front portion of the pair of waist parts 20 is also referred to as the ventral waist part 20, and the rear portion is also referred to as the dorsal waist part 30. The ventral waist part 20 and the dorsal waist part 30 are joined at both sides in the left-right direction by a pair of side joining parts SS. The joining method based on the side joining parts SS can be exemplified by a joining method using heat welding, ultrasonic welding, adhesive, etc.

[0066] like Figure 3 As shown in the figure, the absorbent body 10 has: an absorbent core 11; a liquid-permeable top sheet 12, which is arranged at a position closer to the skin side than the absorbent core 11; a liquid-impermeable back sheet 13, which is arranged at a position closer to the non-skin side than the absorbent core 11; and an outer sheet 14. The absorbent core 11 can be any absorbent core that absorbs and retains excrement, for example, an absorbent core formed into a predetermined shape by a liquid absorbent material such as pulp fiber or superabsorbent polymer. In addition, the absorbent core 11 can also be covered by a liquid-permeable sheet such as a tissue or a nonwoven fabric.

[0067] like Figure 2 As shown, a leg elastic member 15 (e.g., an elastic string) that stretches and contracts along the length direction of the absorbent body 10 may be provided on both sides of the absorbent body 10 in the left-right direction. Furthermore, a leak-proof wall that can stand up toward the skin side may be provided at a position that is closer to the inside in the left-right direction than the leg elastic member 15. For example, the leak-proof wall is formed by folding back both sides of the outer sheet 14 in the left-right direction so as to be located on the skin side of the top sheet 12, and providing a leak-proof wall elastic member 16 (e.g., an elastic string) that stretches and contracts along the length direction at the folded-back position.

[0068] In the present embodiment, the part overlapping with the side joint part SS in the vertical direction is set as the waistline part 20, 30, and the ventral waistline part 20 and the dorsal waistline part 30 are rectangular parts in a plan view. A roughly trapezoidal extension part 30E is provided on the lower crotch side of the dorsal waistline part 30. The extension part 30E can be used to cover the buttocks of the wearer. In the following description, the dorsal waistline part 30 and the extension part 30E are also referred to as the dorsal outerwear part 30, 30E. However, it is not limited to the above situation, for example, it can be a structure without the extension part 30E on the back side, or it can be a structure with a part extending from the ventral waistline part 20 to the lower crotch side.

[0069] The ventral waistline portion 20 and the back outerwear portion 30, 30E respectively have skin side panels 21, 31, non-skin side panels 22, 32 and waist elastic components 23, 33 (e.g., elastic bands) that can be stretched and retracted in the left and right directions. A plurality of waist elastic components 23, 33 are arranged at intervals between the skin side panels 21, 31 and the non-skin side panels 22, 32 in the up and down directions.

[0070] As the skin side sheets 21, 31 and the non-skin side sheets 22, 32, soft sheet members are preferred, and examples thereof include spunbond nonwoven fabrics, meltblown nonwoven fabrics, SMS (spunbond / meltblown / spunbond) nonwoven fabrics, etc. The structural fibers of the nonwoven fabrics are not limited to single fibers of polypropylene (PP), which is a representative example of thermoplastic resins, but single fibers of other thermoplastic resins such as polyethylene (PE) can be used, and composite fibers having a sheath-core structure such as PE and PP can also be used.

[0071] The basic structure of the diaper 1 is described above, but the structure of the diaper 1 is an example and is not limited thereto. For example, in the diaper 1 of the present embodiment, the ventral waistline portion 20 and the dorsal outer covering portions 30, 30E are composed of different components, and the non-skin side of the absorbent body 10 is exposed at the crotch portion. This is not limited thereto, and for example, the diaper may have an outer covering component composed of three components, the ventral waistline portion 20, the dorsal outer covering portions 30, 30E, and the crotch portion connecting them, or may have an outer covering component composed of one component that is continuous from the ventral waistline portion 20 to the dorsal waistline portion 30.

[0072] <<About waistline 20, 30>>

[0073] Figure 4 It is an explanatory diagram of the welded portion rows Ra, Rb, and Rc provided in the abdominal waistline portion 20. Figure 5A and Figure 5B This is an explanatory diagram of the attachment function of the waist elastic member 23. Figure 6A to Figure 6C This is a partially enlarged view of the welded portion rows Ra, Rb, and Rc.

[0074] exist Figure 4 In the drawings, the state of the ventral waistline 20 when stretched in the left-right direction is shown. The state of the waistline 20, 30 (elastic region) stretched in the left-right direction refers to the state of stretching to the extent that the wrinkles generated in the waistline 20, 30 cannot be visually confirmed, and refers to the state of stretching to the extent that the size of each component (such as the skin side sheet 21, etc.) constituting the waistline 20, 30 is consistent with the size of the component alone (that is, the size when the elastic component does not show stretchability) or becomes a length close to it.

[0075] <Regarding the Position Limitation of the Waist Elastic Member 23>

[0076] The ventral waistline portion 20 and the dorsal waistline portion 30 are composed of a stretchable sheet, and the stretchable sheet is provided with a plurality of waist elastic members 23, 33 (elastic members) that can be stretched in the left and right directions at intervals in the vertical direction between the skin side sheets 21, 31 and the non-skin side sheets 22, 32 (between a pair of sheets) joined by a plurality of welding parts 50. The skin side sheets 21, 31 and the non-skin side sheets 22, 32 are intermittently joined using a plurality of welding parts 50 dispersedly arranged in the vertical direction and the left and right directions. The forming method of the welding part 50 can exemplify well-known welding methods such as ultrasonic welding and heat welding.

[0077] The pair of sheets joined by the welding part 50 may be two different sheets like the skin side sheets 21, 31 and the non-skin side sheets 22, 32 of the present embodiment, or may be a sheet formed by folding back a sheet to form two layers. In addition, the welding part 50 is not limited to joining only a pair of sheets sandwiching the waist elastic members 23, 33, but may also be a sheet that is stacked with a pair of sheets and joins three or more layers of sheets.

[0078] Since the abdominal waistline portion 20 and the dorsal waistline portion 30 have substantially the same structure, the abdominal waistline portion 20 will be described below as a representative of both.

[0079] The abdominal waistline portion 20 has a plurality of welded portion rows Ra, Rb, and Rc, in which a plurality of welded portions 50 are arranged in the vertical direction. The plurality of welded portion rows Ra, Rb, and Rc are arranged at intervals in the horizontal direction. Figure 5A As shown in the figure, the space (non-welded portion) through which the waist elastic member 23 passes is aligned in the vertical direction, and the waist elastic member 23 can be arranged in the horizontal direction. However, the vertical positions of the adjacent non-welded portions in the horizontal direction may be offset, and in this case, the ventral waist portion 20 can also be given elasticity in the horizontal direction.

[0080] like Figure 5A As shown in the figure, the two welded portions 50 adjacent to each other in the vertical direction and sandwiching the waist elastic member 23 are also referred to as a "welded portion pair 51". The upper welded portion 50 and the lower welded portion 50 forming the welded portion pair 51 are arranged at a gap GH in the vertical direction. The size of the gap GH is set to be the same size as or slightly larger than the outer diameter d1 of the waist elastic member 23 in the state where the ventral waist portion 20 is stretched to the maximum in the left-right direction (GH≥d1).

[0081] However, the waist elastic member 23 becomes thicker as it contracts in the left-right direction. Figure 5BAs shown, compared with the maximum outer shape d2 of the waist elastic member 23 in the state where the waist elastic member 23 is contracted in the left-right direction (i.e., the natural state of the ventral waist circumference 20), the interval GH of the welding part pair 51 is reduced (GH<d2). As a result, the waist elastic member 23 in the state of contraction in the left-right direction is sandwiched between the welding part pair 51 (the expansion in the up-down direction is limited). Therefore, the position (action) of the waist elastic member 23 relative to the skin side piece 21 and the non-skin side piece 22 in the left-right direction and the up-down direction is limited.

[0082] Therefore, even if the waist elastic member 23 is fixed to the skin side sheet 21 and the non-skin side sheet 22 without using an adhesive, the positional deviation of the waist elastic member 23 can be suppressed, and the elasticity of the ventral waist portion 20 can be maintained. That is, by utilizing the welded portion 50, the waist elastic member 23 can be installed on the skin side sheet 21 and the non-skin side sheet 22 without using an adhesive or reducing the amount of adhesive used. Therefore, the decrease in the softness of the ventral waist portion 20 (elastic sheet 40) caused by the curing of the adhesive can be suppressed. In addition, the decrease in the elastic properties of the waist elastic member 23 caused by the curing of the adhesive can be suppressed.

[0083] In addition, in the ventral waist circumference 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 portion SS. In detail, when manufacturing the diaper 1, the side joint portion SS is formed in a state where the waist elastic member 23 in an extended state is sandwiched between the skin side sheet 21 and the non-skin side sheet 22, and the end of the waist elastic member 23 is fixed to the side joint portion SS. Therefore, even if the ventral waist circumference portion 20 is greatly extended when the diaper 1 is worn, the waist elastic member 23 can be prevented from falling off between the welded portion pair 51, and the elasticity of the ventral waist circumference portion 20 can be maintained.

[0084] In addition, the relationship between the interval GH of the welding part pair 51 and the outer diameters d1 and d2 of the waist elastic member 23 is not limited to the above case. For example, it is also possible to overlap a part of the waist elastic member 23 with the welding part 50 to such an extent that the waist elastic member 23 is not broken. In this case, the waist elastic member 23 can also be sandwiched between the welding part pair 51 in a state of contraction in the left-right direction, and the position relative to the skin side sheet 21 and the non-skin side sheet 22 in the left-right direction and the up-down direction is restricted.

[0085] In addition, it is not limited to sandwiching all the waist elastic members 23 (elastic members) arranged on the ventral waist circumference portion 20 into the welding portion pair 51 and restricting the position. Alternatively, a part of the waist elastic members 23 may be restricted in position by the welding portion pair 51, and another part of the waist elastic members 23 may be fixed to the skin side sheet 21 and the non-skin side sheet 22 by an adhesive.

[0086] <<Ease of stretching the waistline portions 20 and 30>>

[0087] Fig. 7A and Figure 7B It is an explanatory diagram of the tensile test of the waistline parts 20 and 30. Fig. 8A , Figure 8B , Fig. 9A and Fig. 9B It is a figure which shows the result of a tensile test.

[0088] The diaper 1 has stretchable areas at the ventral waistline portion 20 and the dorsal waistline portion 30, and waist elastic members 23 and 33 (elastic members) that can stretch in the left-right direction are arranged in the stretchable areas. When the user (guardian, childcare worker, etc.) of the shorts-type diaper 1 puts the diaper 1 on the wearer (child), first, puts both hands in through the leg openings LH or the waist openings BH, and quickly expands the annular waistline portions 20 and 30 in the left-right direction. Then, 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 the wearing.

[0089] At this time, the user expands the waist parts 20 and 30 in the left-right direction at a relatively fast speed, and expands them at a speed that does not take 1 second. On the other hand, when the diaper 1 is worn, the waist parts 20 and 30 expand relatively slowly due to the wearer's breathing and other movements.

[0090] As a result of the present applicant's intensive research, the following has been found for a general waist portion in which the waist elastic member is fixed to the sheet by continuously applying an adhesive such as a hot melt adhesive in the longitudinal direction of the waist elastic member: It has been found that when the waist portion is stretched at a high speed, the stretching stress (the resistance of the waist portion during stretching) becomes higher than when the waist portion is stretched at a low speed, and the difference is large.

[0091] It can be considered that this is because it is affected by the adhesive that solidifies in the contracted state of the waistline. When the waistline is expanded at a low speed, the solidified resin can be gradually deformed, but when the waistline is expanded at a high speed, the solidified resin needs to be deformed all at once. It can be considered that the resistance of the adhesive will affect the elongation stress (difficulty of expansion) of the waistline. In particular, since the diaper is bundled in the package and circulated for a long time in a contracted state, the curing degree of the adhesive is easily increased. Therefore, it can be considered that when the waistline of the diaper taken out of the package is initially expanded in order to wear the diaper, it is more susceptible to the curing of the adhesive. Users who feel the difficulty of expanding the waistline when wearing the diaper 1 (higher stress when stretching at a high speed) may have the impression of a product with strong tightening that is tightened to a degree higher than the fit of the waistline in actual wear (lower stress when stretching at a low speed).

[0092] Therefore, in the diaper 1, the difference between the stretching stress when the waist portions 20, 30 are stretched at a high speed and the stretching stress when the waist portions 20, 30 are stretched at a low speed is minimized. Specifically, the following aspects are adopted.

[0093] First, a part of the stretchable region of the waistline portions 20 and 30 is used as a test piece T.

[0094] Then, if Fig. 7A , Figure 7B As shown, the force (N) measured when the test piece T is stretched in the horizontal direction at a speed of 50000 mm / min to a length of 84% of the maximum stretch is divided by the width (mm) in the vertical direction of the test piece T is set as the first measured value A1 (N / mm).

[0095] The force (N) measured when the test piece T is stretched horizontally at a speed of 500 mm / min to a length of 84% of the maximum stretch is divided by the vertical width (mm) of the test piece, and is referred to as a second measured value A2 (N / mm).

[0096] The value obtained by dividing the first measurement value A1 by the second measurement value A2 is smaller than 1.2.

[0097] A1 (stress at high-speed elongation) / A2 (stress at low-speed elongation) < 1.2.

[0098] The stress during high-speed extension (first measured value A1) corresponds to the resistance felt by the user from the waist portions 20, 30 when the user quickly expands the waist portions 20, 30 when wearing the diaper 1. On the other hand, the stress during low-speed extension (second measured value A2) corresponds to the resistance (fitting feeling) felt by the wearer from the waist portions 20, 30 when the wearer performs slow movements such as breathing.

[0099] Therefore, according to the diaper 1 of the present embodiment, the difference between the stress during high-speed elongation (first measured value A1) and the stress during low-speed elongation (second measured value A2) can be suppressed from becoming smaller, compared with the case where the value obtained by dividing the first measured value A1 by the second measured value A2 is 1.2 or more. That is, the difference between the ease of elongation of the waist circumference 20, 30 when the diaper 1 is worn and the ease of elongation of the waist circumference 20, 30 during wear can be reduced. Therefore, when the waist circumference 20, 30 is quickly expanded in order to wear the diaper 1, it can be expanded with a smaller force, and the ease of wearing of the diaper 1 is improved. In addition, it is possible to suppress the user's impression that the product is strongly tightened to a degree that is tightened to a degree that exceeds the fit of the waist circumference 20, 30 during wear (lower stress during low-speed elongation).

[0100] In particular, in the case of the infant diaper 1 and the nursing diaper of the present embodiment, since the user (guardian, caregiver, etc.) does not actually wear the diaper 1, it is easy to judge the tightening feeling during wearing by the ease of expansion of the waistline 20, 30 when wearing. Even in this case, according to the diaper 1 of the present embodiment, it is easy to expand the waistline 20, 30 at a high speed, so it is possible to prevent the user from having the impression that the product is tightly tightened.

[0101] Furthermore, by suppressing the stress during high-speed extension, the waistline portions 20 and 30 can be easily extended (good tracking performance) even when the wearer moves quickly, and the wearer can easily move. In addition, in contrast, in the diaper 1, since the stress during low-speed extension is not too low, a moderate fit can be obtained during wearing.

[0102] In addition, 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 welded portions 50 .

[0103] The waist elastic members 23 and 33 are contracted in the left-right direction. Figure 5B As shown, the vertical position of the pair of sheets is restricted by being sandwiched between two welded portions 50 adjacent to each other in the vertical direction.

[0104] Therefore, the amount of adhesive used to restrict the position of the waist elastic members 23 and 33 relative to the sheet can be reduced. Therefore, even when the waist portions 20 and 30 are stretched at a high speed, the influence of the adhesive curing can be reduced, and the stress during high-speed stretching (first measured value A1) can be suppressed, and the difference from the stress during low-speed stretching (second measured value A2) can be reduced.

[0105] However, the present invention is not limited to the above case, and the waist elastic members 23 and 33 may be attached to the sheet using an adhesive instead of the welded portion 50. In this case, in order to reduce the influence of curing of the adhesive during high-speed elongation, the coating pattern and coating amount of the adhesive may be adjusted so that the value obtained by dividing the first measured value A1 by the second measured value A2 is smaller than 1.2.

[0106] In addition, in the present embodiment, the waist elastic members 23 and 33 are attached to the sheet using the welded portion 50 in both the ventral waistline portion 20 and the dorsal waistline portion 30, but the waist elastic member may be attached to the sheet using an adhesive in one of the waistline portions. In addition, the dorsal waistline portion 30 may have an extension portion 30E at a position lower than the side joint portion SS and an elastic member (with the same elastic member) along the left and right directions may also be arranged in the extension portion 30E. Figure 2In the case of a different structure, the elastic member may be attached to the sheet by using the welded portion 50 or by using an adhesive.

[0107] In addition, if Fig. 7A , Figure 7B As shown, in a test in which the test piece T is stretched to 84% of the maximum stretch at a speed of 50,000 mm / min and then contracted to 66% of the maximum stretch after 15 seconds from the start of stretching, the following method can be adopted.

[0108] First, the force (N) measured when the test piece T is contracted to 66% of the maximum elongation is divided by the vertical width (mm) of the test piece T to obtain a third measured value A3 (N / mm).

[0109] In addition, the value obtained by dividing the force (N) measured 585 seconds after the test piece T was contracted to 66% of the length at the maximum extension (i.e., 600 seconds after the start of the test) by the width (mm) in the vertical direction of the test piece T is set as the fourth measured value (N / mm).

[0110] Preferably, the value obtained by dividing the fourth measured value A4 by the third measured value A3 is 0.95 or more. Preferably, A4 (stress when shrinkage is stable) / A3 (stress immediately after shrinkage) ≥ 0.95.

[0111] When wearing the diaper 1, the user greatly expands the waist circumference 20, 30 (e.g., about 84% of the maximum extension), and then the waist circumference 20, 30 contracts in accordance with the wearer's waist circumference (e.g., about 66% of the maximum extension). Immediately after the waist circumference 20, 30 contracts, a relatively large tightening force (stress when the waist circumference 20, 30 returns, third measured value A3) acts. This tightening force decreases and stabilizes over time.

[0112] According to the diaper 1 of this embodiment, compared with the case where the value obtained by dividing the fourth measured value A4 by the third measured value A3 is smaller than 0.95, the third measured value A3 immediately after the waist circumference 20, 30 contracts can be suppressed and brought closer to the fourth measured value A4. Therefore, the strong tightening force immediately after the waist circumference 20, 30 of the diaper 1 fits the wearer can be reduced, and the discomfort immediately after wearing can be reduced. On the contrary, even if the waist circumference 20, 30 continues to be stretched to match the wearer, the fourth measured value A4 does not drop excessively, and it can be said that the fit can be maintained. However, this is not limited to the above case, and the value obtained by dividing the fourth measured value A4 by the third measured value A3 may be less than 0.95.

[0113] In addition, if Fig. 7AAs shown, the test piece T may be the entire region of the ventral waistline portion 20 and the dorsal waistline portion 30 joined into a ring shape by the side joint portion SS. In this case, since the relationship of the above-mentioned measured values ​​(A1 / A2<1.2, A4 / A3≥0.95) holds, it can be said that the stress difference between the state when the actual diaper 1 is worn and the state close to the state of wearing is small, and it can be said that the feeling of tightening immediately after wearing can be suppressed.

[0114] Moreover, if Figure 7B As shown, even if the test piece T is set as the ventral waistline portion 20 and the dorsal waistline portion 30 joined into a ring shape by the side joint portion SS, the portion Au (refer to Figure 2 ), the above relationship of the measured values ​​(A1 / A2<1.2, A4 / A3≥0.95) also holds.

[0115] The upper part Au of the waist parts 20 and 30 is more likely to affect the ease of expansion and the tightening feeling of the waist parts 20 and 30 than the lower part. Therefore, by suppressing the stress (A1) during high-speed extension and reducing the difference from the stress (A2) during low-speed extension at the upper part Au of the waist parts 20 and 30, it is easier to expand the waist parts 20 and 30, and the impression of a product with strong tightening can be reduced. In addition, the tightening feeling of the waist parts 20 and 30 immediately after wearing can be reduced.

[0116] In addition, the test piece T is not limited to the annular waist parts 20 and 30 , and the ventral waist part 20 after the side joint part SS is separated may be used as the test piece T, or the dorsal waist part 30 may be used as the test piece T.

[0117] In this case, the value obtained by dividing the first measured value A1 by the second measured value A2 when the back waistline portion 30 is the test piece T may be smaller than the value obtained by dividing the first measured value A1 by the second measured value when the ventral waistline portion 20 is the test piece T. That is, the stress (A1) during high-speed elongation in the back waistline portion 30 may be suppressed so that the difference from the stress (A2) during low-speed elongation is small. Thus, even at high speed, the back waistline portion 30 can be easily extended, and when the diaper 1 is worn, the back waistline portion 30 can be greatly expanded so as to cover the buttocks.

[0118] On the contrary, the value obtained by dividing the first measured value A1 by the second measured value A2 when the ventral waistline portion 20 is the test piece T may be smaller than the value obtained by dividing the first measured value A1 by the second measured value A2 when the dorsal waistline portion 30 is the test piece T. That is, the stress (A1) during high-speed elongation may be suppressed in the ventral waistline portion 20, so that the difference from the stress (A2) during low-speed elongation becomes smaller. In this case, the ventral waistline portion 20 is easily elongated even at high speed, and the ventral waistline portion 20 is easily expanded when the diaper 1 is worn, so that when the wearer's feet are passed through the waist opening BH, it is possible to suppress the feet (particularly the toes) from being caught.

[0119] In addition, the absorbent article is not limited to the pants-type diaper 1, and may also be a belt-type diaper. In this case, for example, in the back waistline of the belt-type diaper (the area on the back side when the product length is divided into three parts), a stretchable area (so-called back pleated part) may be provided in the central part in the left-right direction, or a stretchable fastening belt (stretching area) may be provided at the end in the left-right direction (protruding from the main body in the left-right direction). In the case where these stretchable areas are used as the test piece T, the value obtained by dividing the first measured value A1 by the second measured value A2 is also made smaller than 1.2. As a result, when the belt-type diaper is worn, the fastening belt and the main body on the back side are easily stretched, which can prevent the user from having the impression of a product with strong tightening.

[0120] <Method of measuring first measurement value A1 and second measurement value A2>

[0121] Next, a method for measuring the first measurement value A1 and the second measurement value A2 will be described.

[0122] The measurement is performed using a tensile testing machine (for example, Autograph, Model AGS-1kNG, manufactured by Shimadzu Corporation, or an equivalent device) in a test environment at a room temperature of 23°C ± 2°C and a humidity of 50% ± 5%.

[0123] (1) First, prepare two diapers 1 just taken out of the package. That is, prepare two diapers 1 having the same structure of the test piece T. For example, Fig. 7A In the test piece T, the entire region of the ventral waistline portion 20 and the dorsal waistline portion 30 connected in a ring shape is used as the test piece T. Therefore, the width of the test piece T in the vertical direction is the length W of the side joint portion SS in the vertical direction.

[0124] exist Figure 7B In the test piece T, the upper half of the ventral waistline 20 and the dorsal waistline 30 connected in a ring shape (Au) is used as the test piece T. Therefore, the width of the test piece T in the vertical direction is half the length W / 2 of the side joint SS in the vertical direction. In this case, in order not to be affected by the elasticity of the lower half of the waistline 20, 30, the test piece T is used. Figure 2 The cut line C1 shown cuts off a part of the waistline 20, 30. The cut line C1 is a line extending from the side ends of the waistline 20, 30 in the left-right direction to the side of the absorbent body 10 at the center CL of the waistline 20, 30 in the left-right direction.

[0125] As described above, the test piece T refers to a part or all of the stretchable area of ​​the waist parts 20 and 30. The test piece T is set in the clamps 61 and 61 of the tensile tester 60, but the test is performed in a state where parts other than the test piece T (for example, the absorbent body 10 and the lower half of the waist parts 20 and 30) are also connected to the test piece T. Therefore, elastic members that affect the stretchability in the left-right direction (for example, the leg elastic members that are arranged along the leg opening LH with an inclination relative to the vertical direction, although not shown in the figure) other than the waist elastic members 23 and 33 are cut in advance.

[0126] (2) Next, the interval between the clamps 61 and 62 of the tensile testing machine 60 is adjusted according to the size of the diaper 1. The length from the upper end of the upper clamp 61 to the lower end of the lower clamp 62 is defined as the inter-clamp length L2. In the present embodiment, the initial inter-clamp distance L2 (e.g., 140 mm) is set so that the waistline portions 20 and 30 are stretched by about 41% (e.g., 38% to 45%) relative to the left-right dimension of the waistline portions 20 and 30 when the waistline portions 20 and 30 are stretched to their maximum extent (e.g., L1 = 345 mm).

[0127] (3) Next, the test piece T of the diaper 1 is placed in the clamps 61 and 62 of the tensile tester 60. The tensile direction of the tensile tester 60 is matched with the expansion and contraction direction of the test piece T (the left-right direction of the diaper 1). When the test piece T is an annular waist portion 20 or 30, the side joint SS is placed at the upper end of the upper clamp 61 and the lower end of the lower clamp 62. When the test piece T is not annular, the test piece T (for example, one of the ventral waist portion 20 and the dorsal waist portion 30, or the dorsal waist portion of a belt-type diaper) is clamped with a clip-type clamp, and the entire absorbent article in the unfolded state is placed in the tensile tester. In this case, the center of the clamp in the width direction (the direction perpendicular to the tensile direction) is placed in line with the center of the test piece T in the direction perpendicular to the expansion and contraction direction (the vertical direction of the diaper 1).

[0128] (4) Next, the test piece T is stretched at a speed of 50000 mm / min to a length of 84% of the maximum stretch (e.g., L2 = 345 × 0.84 = 290 mm), and the force (N) measured when stretched to 84% is obtained. The value obtained by dividing the force by the width (mm) of the test piece T is set as the first measured value A1 (N / mm).

[0129] Since the tensile testing machine 60 used in this embodiment cannot cope with a speed of 50,000 mm / min, one of the clamps 62 is pulled manually. Specifically, it takes about 0.18 seconds to pull a distance of 150 mm (= 290 mm - 140 mm). When it is performed manually, it is not limited to strictly elongating 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 clamp 62 manually, and it is also possible to use a tensile testing machine that can cope with high speeds for measurement.

[0130] (5) Next, remove the test piece T (diaper 1) stretched at high speed from the clamps 61 and 62, and set the other test piece T (diaper 1) in the same manner on the clamps 61 and 62. Stretch the test piece T at a speed of 500 mm / min to a length of 84% of the maximum stretch (for example, L2 = 290 mm). Instead of stretching it manually, stretch it mechanically using a tensile tester 60. Then, obtain the force (N) measured when it is stretched to 84%. The value obtained by dividing the force by the width (mm) of the test piece T is set as the second measured value A2 (N / mm).

[0131] (6) Finally, calculate the value obtained by dividing the first measured value A1 by the second measured value A2 (round off to the third decimal place), and check whether the value is less than 1.2. In addition, since the test piece T of the same width is stretched at a varying speed, it is not necessary to convert it into the force per unit width (N / mm).

[0132] That is, the value obtained by dividing the force (N) obtained from the tensile tester 60 during high-speed extension by the force (N) obtained from the tensile tester 60 during low-speed extension may be the value obtained by dividing the first measured value A1 by the second measured value A2.

[0133] <Method of measuring third measurement value A3 and fourth measurement value A4>

[0134] Next, a method for measuring the third measurement value A3 and the fourth measurement value A4 will be described.

[0135] (1) The test piece T is set in the jigs 61 and 62, and the test piece T is stretched at a speed of 50,000 mm / min to a length of 84% of the maximum stretch. The measurement method is the same as above.

[0136] (2) Then, when 15 seconds have passed from the start of the test, the test piece T is contracted so that the test piece T becomes 66% of the length at the maximum extension (for example: L2 = 228 mm = 345 × 0.66).

[0137] The test piece T is contracted at the same high speed (50000 mm / min) as when it was stretched. When the tensile tester 60 cannot cope with the high speed, the clamp 62 is moved manually. Specifically, 62 mm (= 290-228) is moved in 0.07 seconds, but when it is performed manually, it is not limited to contracting at a speed of strictly 50000 mm / min. Then, the force (N) measured when the test piece T is contracted to 66% of the length at the maximum elongation is obtained. The value obtained by dividing the force by the width (mm) of the test piece T is set as the third measured value A3 (N / mm).

[0138] (3) Thereafter, the test piece T is maintained in a state of being stretched to 66% of the length at the maximum stretch.

[0139] The force (N) measured at 600 seconds from the start of the test (i.e., 585 seconds after the test piece T shrinks from 84% to 66%) is obtained. The value obtained by dividing the force by the width (mm) of the test piece T is set as the fourth measured value A4 (N / mm).

[0140] (4) Then, the value obtained by dividing the fourth measured value A4 by the third measured value A3 is calculated (rounded to the third decimal place), and it is confirmed whether the value is 0.95 or more. In addition, since it is a change in the measured value of the test piece T of the same width, it is not necessary to convert it into the force (N / mm) per unit width. That is, the value obtained by dividing the force (N) obtained from the tensile tester 60 585 seconds after the contraction by the force (N) obtained from the tensile tester 60 just after the contraction may be set as the value obtained by dividing the fourth measured value A4 by the third measured value A3.

[0141] <Example>

[0142] Diapers of the comparative examples and the examples were actually manufactured and the above measurements were performed. Figure 1 to Figure 3 The shorts-type diaper of the structure shown in the figure. The length L1 of the waist parts 20 and 30 in the left-right direction when the waist parts 20 and 30 are stretched to the maximum is set to 345 mm, and the length W in the up-down direction is set to 127 mm. The stretching ratio of the waist elastic members 23 and 33 is set to 2.8 times, and the thickness is set to 470 dtex. The number of waist elastic members 23 of the ventral waist part 20 is set to 9, and the number of waist elastic members 33 of the dorsal waist part 30 is set to 10.

[0143] In the diaper of the comparative example, the hot melt adhesive is applied continuously along the entire circumference of the waist elastic members 23 and 33 in the longitudinal direction, and is attached between the skin side sheets 21 and 22 and the non-skin side sheets 31 and 32 in a stretched state.

[0144] In the diaper of the embodiment, Figures 4 to 6CAs shown, the waist elastic members 23, 33 are attached between the skin side sheets 21, 22 and the non-skin side sheets 31, 32 using the welded portions 50. Three types of welded portion arrays Ra to Rc are formed at intervals of 5 mm in the left-right direction in the waist portions 20, 30.

[0145] like Fig. 6A As shown in FIGS. 1 and 10 , in the welded portion rows Ra to Rc, welded portions 50 are continuously formed in the up-down direction outside the regions where the waist elastic members 23 and 33 are located.

[0146] In the first welded portion row Ra ( Fig. 6A ), the welded portion 50 having a length Wa of 2.5 mm in the left-right direction is arranged in a straight line along the vertical direction. The length GH in the vertical direction of the region where the waist elastic members 23 and 33 are located is set to 0.28 mm. Figure 4 As shown in FIG. 1 , two first welded portion rows Ra are formed at a position immediately inside the side joining portion SS and two at a position immediately outside the absorbent body 10 .

[0147] In the second welded portion row Rb ( Figure 6B ), the welded parts 50 with a length Wb of 0.5 mm in the left-right direction are arranged in the up-down direction in a slightly zigzag manner in the left-right direction. The up-down length GH of the region where the waist elastic members 23 and 33 are located is the same as that of the first welded part row Ra, which is 0.28 mm. The second welded part row Rb is formed between the first welded part rows Ra at a position further outward than the absorbent body 10.

[0148] In the third welded portion row Rc ( Figure 6C ), the welded parts 50 with a length Wc of 0.5 mm in the left-right direction are arranged linearly along the vertical direction. The vertical length GHc of the area where the waist elastic members 23 and 33 are located is relatively wide, 0.6 mm. The third welded part row Rc is formed in the area overlapping with the absorbent body 10.

[0149] In addition, Figure 6A to Figure 6C In the illustrated welded portion rows Ra to Rc, a plurality of welded portions 50 are arranged at intervals in the vertical direction. However, in the diaper produced as an example, welded portions 50 are formed continuously in the vertical direction outside the spaces where the waist elastic members 23 and 33 are located.

[0150] Regarding the diapers of the comparative examples and the examples, Fig. 8A and Figure 8B Result obtained by dividing the first measured value A1 by the second measured value A2 is shown in FIG. Fig. 8AThe results are obtained by taking the entire area of ​​the waist parts 20 and 30 connected in a ring shape as the test piece T. In the diaper of the comparative example, the force (a1) measured at the time of high-speed extension is 14.739 (N), and the force (a2) measured at the time of low-speed extension is 10.761 (N). Therefore, the value (a1 / a2) obtained by dividing the first measured value A1 by the second measured value A2 is 1.37, which is larger than 1.2.

[0151] On the other hand, in the diaper of the example, the force (a1) measured at the high-speed extension was 10.133 (N), and the force (a2) measured at the low-speed extension was 9.260 (N). Therefore, the value (a1 / a2) obtained by dividing the first measured value A1 by the second measured value A2 is 1.09, which is smaller than 1.2.

[0152] Figure 8B The results are shown in FIG. 1 , where the upper half of the waist portions 20 and 30 connected in a ring shape was used as the test piece T.

[0153] In the comparative example diaper, the force (a1) measured at high speed extension was 6.863 (N), and the force (a2) measured at low speed extension was 5.281 (N). Therefore, the value (a1 / a2) obtained by dividing the first measured value A1 by the second measured value A2 was 1.30, which was greater than 1.2.

[0154] On the other hand, in the diaper of the example, the force (a1) measured at the high-speed extension was 5.516 (N), and the force (a2) measured at the low-speed extension was 4.852 (N). Therefore, the value (a1 / a2) obtained by dividing the first measured value A1 by the second measured value A2 is 1.14, which is smaller than 1.2.

[0155] From the above results, it can be seen that in the embodiment in which the waist elastic members 23 and 33 are mounted using the welded portion 50, the stress (A1, a1) during high-speed elongation can be suppressed, and the difference from the stress (A2, a2) during low-speed elongation can be reduced, compared with the comparative example in which a large amount of adhesive is used to mount the waist elastic members 23 and 33. Therefore, it is easy to quickly expand the waist portions 20 and 30 when wearing the diaper, and the impression of a product with a strong sense of tightening can be reduced.

[0156] In addition, the subjects (21 people) were asked to evaluate the wearability of the diapers of the comparative example and the embodiment. As a result, the proportion of people who evaluated that the waist stretchability of the diapers of the embodiment was very good or slightly better than that of the diapers of the comparative example was 69%. The proportion of people who evaluated that the diapers of the embodiment were very easy to wear or slightly easy to wear compared with the diapers of the comparative example was 71%. In addition, the proportion of people who evaluated that the diapers of the embodiment did not tighten the body very much or slightly did not tighten the body compared with the diapers of the comparative example was 69%. From the above results, it can be seen that for diapers with a value smaller than 1.2 obtained by dividing the first measured value A1 by the second measured value A2, the stretchability of the waist is better, the diaper is easy to wear, and the impression that it does not tighten the body can be obtained.

[0157] In addition, regarding the diapers of the comparative examples and the examples, Fig. 9A and Fig. 9B Result obtained by dividing the fourth measurement value A4 by the third measurement value A3 is shown in FIG. Fig. 9A The results are shown for the entire area of ​​the annular waist circumference 20, 30 as the test piece T. In the comparative example diaper, the measured value immediately after shrinking to 66% is 4.482N, and the measured value 600 seconds after the start of the test is 4.192N. Therefore, the value (a4 / a3) obtained by dividing the fourth measured value A4 by the third measured value A3 is 0.94, which is smaller than 0.95. On the other hand, in the example diaper, the measured value immediately after shrinking is 3.248N, and the measured value 600 seconds after is 3.082N. Therefore, the value (a4 / a3) obtained by dividing the fourth measured value A4 by the third measured value A3 is 0.95.

[0158] Fig. 9B The results are shown with the upper half of the waistline portions 20 and 30 as the test piece T. In the comparative example diaper 1, the measured value immediately after contraction was 2.228 N, the measured value after 600 seconds was 2.068 N, and the value obtained by dividing the fourth measured value A4 by the third measured value A3 (a4 / a3) was 0.93, which was smaller than 0.95. On the other hand, in the example diaper, the measured value immediately after contraction was 1.845 N, the measured value after 600 seconds was 1.747 N, and the value obtained by dividing the fourth measured value A4 by the third measured value A3 (a4 / a3) was 0.95.

[0159] From the above results, it can be seen that in the embodiment in which the waist elastic members 23 and 33 are attached by the welded portion 50, the stress (A3, a3) immediately after shrinking to 66% is low, and the difference from the stress (A4, a4) when the shrinkage is stable is also small. Therefore, in the diaper of the embodiment, after the waist portions 20 and 30 are greatly expanded for wearing, it is possible to suppress the strong tightening feeling given to the wearer immediately after the waist portions 20 and 30 are shrunk to match the wearer. In addition, the change in the tightening feeling (fitting feeling) during wearing is small, which can reduce the discomfort during wearing.

[0160] <Other Features>

[0161] At least one of the abdominal waistline portion 20 and the dorsal waistline portion 30 may be configured as follows.

[0162] like Figure 4 As shown, in the waist parts 20 and 30, when a plurality of waist elastic members 23 and 33 are arranged at intervals in the vertical direction, all waist elastic members 23 and 33 overlapping the side joint SS in the vertical direction are positionally restricted by the welded parts 50. That is, preferably, all waist elastic members 23 and 33 provided in the waist parts 20 and 30 are sandwiched between two welded parts 50 adjacent in the vertical direction in a state of contraction in the left-right direction, thereby restricting the position in the vertical direction relative to the pair of sheets (21 and 22, 31 and 32).

[0163] Thus, the amount of adhesive disposed in the waistline 20, 30 can be further reduced, and even when the waistline 20, 30 is stretched at a high speed, it is difficult to be affected by the curing of the adhesive. Therefore, the stress during high-speed stretching can be suppressed, and the difference between the stress during low-speed stretching can be reduced. Therefore, it is easy to quickly expand the waistline 20, 30, the wearability is good, and the user can be prevented from having the impression that the product is tightly tightened.

[0164] However, the present invention is not limited to the above case, and a portion of the waist elastic members 23, 33 (preferably four or less waist elastic members 23, 33) of the waist portions 20, 30 may be attached to the sheet using an adhesive instead of the welded portion 50.

[0165] In addition, if Figure 4As shown, the waist elastic members 23 and 33 may be positioned by the welded portion 50 over the entire area in the left-right direction between a pair of side joints SS. In this case, the amount of adhesive disposed in the waist portions 20 and 30 can be reduced, the stress during high-speed elongation can be suppressed, and the difference in stress from that during low-speed elongation can be reduced. However, the present invention is not limited to the above case, and a portion of the waist elastic member 23 in the left-right direction may be positioned by the welded portion 50, and the other portion may be attached to the sheet using an adhesive.

[0166] In the diaper 1, when the diaper 1 is worn, the ends of the waist portions 20, 30 in the left and right directions are stretched and pulled up. Therefore, the waist elastic members 23, 33 are more likely to break and fall off at the ends in the left and right directions of the diaper 1 than at the center portion. In addition, in the case of the shorts-type diaper 1, the waist elastic members 23, 33 may be cut when the side joints SS are formed.

[0167] In addition, if Figure 6A to Figure 6C As shown, the waist circumference parts 20 and 30 have a plurality of welded part pairs 51, which are two welded parts 50 located adjacent to each other in the vertical direction and sandwiching the waist elastic members 23 and 33. The plurality of welded part pairs 51 may include: a welded part pair (first welded part pair) with a smaller vertical length GH between the welded parts 50, specifically, a welded part pair 51a of the first welded part column Ra and a welded part pair 51b of the second welded part column Rb; and a welded part pair (second welded part pair) with a larger vertical length GHc of the welded part 50 located closer to the center in the left-right direction than the first welded part pair, specifically, a welded part pair 51c of the third welded part column Rc. In addition, the waist circumference parts 20 and 30 only need to have at least one set of the first welded part pair and the second welded part pair. In addition, the second welded portion pair (the welded portion pair 51 c of the third welded portion row Rc) does not need to be in contact with the waist elastic members 23 , 33 .

[0168] Thus, the waist elastic members 23 and 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 ends of the waist portions 20 and 30 in the left-right direction. Therefore, even if the waist elastic members 23 and 33 are broken at the side joints SS, the cut ends of the waist elastic members 23 and 33 can be easily held by the welded portion pairs 51a and 51b near the side joints SS. Therefore, stretchability can be ensured over a wide range of the waist portions 20 and 30 in the left-right direction.

[0169] On the other hand, in the central part of the waist circumference 20, 30 in the left-right direction, the interval GHc of the welding part 50 in the vertical direction is wide, so it is possible to suppress the waist elastic members 23, 33 from being cut when the welding part 50 is formed. Even if the interval GHc of the welding part 50 in the vertical direction is wide, it is possible to limit the large positional deviation of the waist elastic members 23, 33 in the vertical direction. In addition, the welding part 50 can be used to suppress the floating of the skin side sheets 21, 31 and the non-skin side sheets 22, 32. Therefore, compared with the case where the adhesive is used to suppress the floating of the sheet, the amount of adhesive used in the waist circumference 20, 30 can be reduced. Therefore, the stress of the waist circumference 20, 30 during high-speed extension can be suppressed, and the difference with the stress during low-speed extension can be reduced, so that the waist circumference 20, 30 can be easily expanded quickly. In addition, in the left-right center portion of the waist portions 20, 30 (third welded portion row Rc), the friction between the welded portion 50 and the waist elastic members 23, 33 is reduced, so from this point of view, it can be said that the waist portions 20, 30 are easily expanded.

[0170] In addition, the plurality of welded portion pairs 51 may include: a welded portion pair (third welded portion pair) having a longer length Wa of the welded portion 50 in the left-right direction, specifically, a welded portion pair 51a of the first welded portion row Ra; and a welded portion pair (fourth welded portion pair) having shorter lengths Wb and Wc of the welded portion 50 in the left-right direction located closer to the center side than the third welded portion pair, specifically, a welded portion pair 51b of the second welded portion row Rb and a welded portion pair 51c of the third welded portion row Rc. In addition, the waistline portions 20 and 30 only need to include at least one set of the third welded portion pair and the fourth welded portion pair.

[0171] By lengthening the left-right length of the welded portion 50, the frictional force generated between the welded portion 50 and the waist elastic member 23 is increased, and the waist elastic members 23 and 33 can be prevented from falling off from the welded portion pair 51. Therefore, even if the waist elastic members 23 and 33 are broken at the side joint SS, the welded portion pair 51a nearby can easily hold the cut ends of the waist elastic members 23 and 33. Therefore, the stretchability can be ensured over a wide range of the waist portions 20 and 30 in the left-right direction.

[0172] On the other hand, in the area farther from the central part side in the left-right direction than the side joint SS, it is not necessary to restrict the waist elastic members 23 and 33 more than necessary by the welded part pair 51. Therefore, by shortening the lengths Wb and Wc of the welded parts 50, the friction between the welded parts 50 and the waist elastic members 23 and 33 is reduced. Therefore, it is easy to expand the waist parts 20 and 30, and the impression of a product with strong tightening can be reduced. In addition, by shortening the length in the left-right direction of the welded parts 50 with high rigidity, the flexibility of the waist parts 20 and 30 can be ensured.

[0173] In addition, if Figure 4 As shown, for the waist elastic members 23, 33 overlapping the absorbent body 10, the waist elastic members 23, 33 may be cut off at the central part of the left-right direction of the diaper 1 to become discontinuous. In the area SB where the waist elastic members 23, 33 become discontinuous parts, there is almost no stretchability, and the stretching force of the waist elastic members 23, 33 per unit width in the vertical direction is reduced compared with the area SA where the waist elastic members 23, 33 are continuous. Therefore, when the diaper 1 is worn, it is easy to expand the waist 20, 30. In addition, it is possible to suppress the absorbent body 10 from shrinking due to the waist elastic members 23, 33, and it is possible to ensure the flatness of the absorbent body 10 (especially the absorbent core 11), and improve the close contact with the wearer.

[0174] Furthermore, if the waist elastic member 23 is cut during the manufacturing process of the diaper 1, the waist elastic member 23 shrinks and its diameter increases, and is sandwiched by the welded portion pair 51 in the middle. Therefore, when the waist portions 20 and 30 are stretched, the cut ends of the waist elastic members 23 and 33 in the stretched state are held by the welded portion pair 51, and the stretchability of the continuous portion SA can be ensured.

[0175] Therefore, if Figure 4 As shown, a first welded portion row Ra having a relatively long welded portion 50 in the left and right directions may be provided at the end portion on the left and right central side of the region (SA) where stretchability is desired. Thus, the cut ends of the waist elastic members 23 cut to form the discontinuous portions of the waist elastic members 23 and 33 are firmly held by the first welded portion row Ra. Thus, the stretchability of the waist portions 20 and 30 (continuous portions SA) can be ensured.

[0176] In addition, if Figure 6A to Figure 6C As shown, the plurality of welded portions 50 provided in the waist circumference portions 20 and 30 include first welded portions 50ah, 50bh, and 50ch adjacent to a waist elastic member 231 (first elastic member). In addition, the plurality of welded portions 50 include second welded portions 50a1, 50b1, and 50cl, which are located in the middle of the waist elastic member 231 and the waist elastic member 232 (second elastic member) adjacent to the waist elastic member 231 in the vertical direction. In this case, the welded strength of the first welded portions 50ah, 50bh, and 50ch adjacent to the waist elastic members 23 and 33 may be stronger than that of the second welded portions 50a1, 50b1, and 50cl.

[0177] Thus, the waist elastic members 23 and 33 can be firmly sandwiched by the first welded parts 50ah and 50bh with high rigidity, and the waist elastic members 23 and 33 can be prevented from falling off from the welded part pair 51. In addition, the vertical positional deviation of the waist elastic members 23 and 33 can be firmly restricted by the first welded parts 50ch with high rigidity.

[0178] On the other hand, by weakening the welding strength of the second welding parts 50a1, 50b1, 50cl located at a position away from the waist elastic members 23, 33, the flexibility of the waist parts 20, 30 can be ensured, and the floating of the skin side sheets 21, 22 and the non-skin side sheets 22, 32 can be suppressed. Therefore, compared with the case where the floating of the sheet is suppressed by the adhesive, the amount of the adhesive used in the waist parts 20, 30 can be reduced. Therefore, the stress during the high-speed elongation of the waist parts 20, 30 can be suppressed, and the difference in stress during the low-speed elongation can be reduced, and the waist parts 20, 30 can be easily expanded quickly. In addition, the difference in the welding strength of the first welding parts 50ah, 50bh, 50ch and the second welding parts 50a1, 50b1, 50cl can be visually judged based on the melting of the sheet. Specifically, when the welding strength is strong, the sheet is completely filmized in the welding part 50. When the welding strength is weak, fibers of the nonwoven fabric remain in the welded portion.

[0179] In addition, in the present embodiment, in the welded portion array Ra~Rc, the welded portions 50 are arranged at intervals in the vertical direction. Therefore, the first welded portions 50ah, 50bh, 50ch and the second welded portions 50al, 50bl, 50cl are arranged non-continuously in the vertical direction. However, this is not limited to this, and the welded portions 50 may be continuous in the vertical direction outside the area where the waist elastic members 23 and 33 are located, and the first welded portions 50ah, 50bh, 50ch and the second welded portions 50al, 50bl, 50cl are continuous. In addition, the second welded portions 50al, 50bl, 50cl may be arranged in a non-continuous manner in the vertical direction compared to the first welded portions 50ah, 50bh, 50ch. Fig. 6A The number of the welded portions 50 may be large as shown in the figure, or the welded portions 50 may be long in the vertical direction although not shown in the figure. Thus, the flexibility of the waistline portions 20 and 30 can be further ensured. For example, the plurality of welded portions 50 may be arranged at intervals in the vertical direction. However, this is not limited to the above case, and the welded portions 50ah, 50bh, 50ch and the second welded portions 50al, 50bl, 50cl may have the same weld strength.

[0180] In addition, if Figure 5AAs shown, preferably, when the waist portions 20, 30 (stretching areas) are stretched in the left-right direction, the length GH in the vertical direction between the two welded portions 50 adjacent in the vertical direction and sandwiching the waist elastic components 23, 33 is greater than the length d1 in the vertical direction of the waist elastic components 23, 33 (GH>d1).

[0181] As the waist circumference parts 20 and 30 extend in the left-right direction, the waist elastic members 23 and 33 become thinner, and the length in the vertical direction becomes shorter (from d2 to d1). At this time, by making the waist elastic members 23 and 33 thinner than the interval GH of the welded part 50, the friction generated between the two can be reduced. Therefore, it is easy to expand the waist circumference parts 20 and 30, and it is possible to prevent users from having the impression that the product is tightly tightened.

[0182] The welded portion 50 has been described above, but the shape, number, and arrangement of the welded portion 50 are not limited to the above. Figure 4 In the embodiment, the welded portion rows Ra to Rc are arranged at a constant interval in the left-right direction, but the present invention is not limited thereto. For example, the intervals in the left-right direction of the welded portion rows Ra to Rc may be narrower in the vicinity of the side joint SS where the waist elastic members 23 and 33 are easily broken, or in the vicinity of the side portion of the absorbent body 10 where the waist elastic members 23 and 33 are cut during manufacturing, compared with other regions. Thus, the cut ends of the waist elastic members 23 and 33 are firmly held by the welded portion rows Ra to Rc.

[0183] In addition, if Figure 3 As shown, in the pants-type diaper 1, an absorbent body 10 and an outer body (abdominal waist portion 20, back waist portion 30, extension portion 30E) located on the non-skin side of the absorbent body 10 are provided. Preferably, when the side joint SS of the diaper 1 is separated and the diaper 1 is unfolded, the waist portions 20, 30 (stretching area) have the outer body sheet stacked in the number of layers of the pair of sheets (skin side sheets 21, 22 and non-skin side sheets 22, 32) sandwiching the waist elastic members 23, 33. In Figure 3 In the embodiment, two-layer regions 25 and 35 are formed between the upper end of the absorbent body 10 and the lower ends of the folded-back portions 24 and 34 of the non-skin side sheets 22 and 32.

[0184] Thus, since there are regions 25 and 35 where the number of stacked sheets is small, the region where the sheets are stacked and joined by adhesive can be reduced in the waist regions 20 and 30, and the amount of adhesive used in the waist regions 20 and 30 can be reduced. Therefore, the stress during high-speed elongation of the waist regions 20 and 30 can be suppressed, and the difference in stress from that during low-speed elongation can be reduced, making it easy to rapidly expand the waist regions 20 and 30.

[0185] In addition, Figure 3 In the embodiment, folding parts 24 and 35 are provided, and the upper end of at least one of the pair of sheets (here, the non-skin side sheets 22 and 32) sandwiching the waist elastic members 23 and 33 is folded back in the vertical direction toward the bottom. In this case, it is preferred that an area without adhesive is provided between the upper end of the absorbent body 10 and the lower end of the folding parts 25 and 35. In the present embodiment, the folding parts 24 and 34 (non-skin side sheets 22 and 32) are joined to the skin side of the skin side sheets 21 and 31 by adhesive, and the non-skin side of the absorbent body 10 is joined to the waist parts 20 and 30 by adhesive. The area 25 and 35 between them is an area without adhesive.

[0186] In this way, since the area where no adhesive is arranged is provided in the waist parts 20 and 30, the amount of adhesive used in the waist parts 20 and 30 can be reduced. Therefore, the stress during high-speed extension of the waist parts 20 and 30 can be suppressed, and the difference in stress from low-speed extension can be reduced, so that the waist parts 20 and 30 can be easily expanded quickly.

[0187] Furthermore, the area where the adhesive is not disposed also includes an area where the adhesive is not disposed in an area where the adhesive is applied in a well-known pattern (e.g., a spiral pattern, an Ω pattern, etc.). That is, it includes an area where the adhesive is not disposed except for an area where the adhesive is applied without gaps (so-called fully applied area).

[0188] In addition, if Figure 2 As shown, it is preferred that, in the unfolded state of the diaper 1, the average unit area weight (g / m2) of the absorbent core 11 is greater at the portion 11b of the absorbent core 11 overlapping with the back waist portion 30 in the thickness direction than at the portion 11f of the absorbent core 11 overlapping with the ventral waist portion 20 in the thickness direction. 2 ) is lower.

[0189] In this case, since the rigidity of the absorbent core 11 located in the back waistline portion 30 is reduced, the back waistline portion 30 is easily stretched. Therefore, when the diaper 1 is worn, the back waistline portion 30 can be greatly expanded to a degree that can cover the buttocks. On the other hand, by increasing the unit weight of the absorbent core 11 in the ventral waistline portion 20 close to the urination part, leakage of excrement can be suppressed.

[0190] Fig. 10A and Fig. 10B : is an explanatory diagram of the waist elastic members 23, 33. Preferably, a lubricant is attached to at least one of the surfaces of the waist elastic members 23, 33 and the inner surfaces of the pair of sheets 21, 22, 31, 32 sandwiching the waist elastic members 23, 33. Fig. 10AIn the embodiment, the lubricant 70 is applied to the waist elastic members 23 and 33. Although not shown in the figure, the lubricant may be applied to the non-skin side of the skin side sheets 21 and 31 and the skin side of the non-skin side sheets 22 and 32.

[0191] This can reduce the friction between the waist elastic members 23, 33 and the skin side sheets 21, 22 and the non-skin side sheets 31, 32. Therefore, the waistline parts 20, 30 can be easily expanded, and the user can be prevented from having the impression that the product is tightly tightened.

[0192] Furthermore, in the manufacturing process of the diaper 1, when the welded portion 50 and the side joint portion SS are formed, even if the convex die plate for forming these presses the waist elastic members 23 and 33, the waist elastic members 23 and 33 can be easily slid by the lubricant 70. Therefore, the waist elastic members 23 and 33 can be easily squeezed out from the convex die plate, and the waist elastic members 23 and 33 can be prevented from being cut.

[0193] In addition, as a lubricant, an oil can be exemplified. The type of the oil is not particularly limited, and for example, the oil may be applied to the elastic fibers 23A constituting the waist elastic members 23 and 33 for the purpose of preventing adhesion and improving processability. Specifically, an oil having dimethyl polysiloxane, a modified polysiloxane obtained by replacing a part of the methyl group with other alkyl groups, phenyl groups, amino groups, etc., mineral oil, etc. as a main component can be used.

[0194] In addition, if Fig. 10A As shown in the figure, it is preferable that the waist elastic members 23, 33 are linear elastic members formed by gathering a plurality of elastic fibers 23A. Thus, even if a part of the elastic fibers 23A are broken in the process of forming the side joint SS, the remaining elastic fibers 23A are connected, so that the waist elastic members 23, 33 can be prevented from being cut. Therefore, it is possible to suppress the waist elastic members 23, 33 from falling off from the welded portion pair 51, and the elasticity of the waist portions 20, 30 can be ensured.

[0195] In addition, since the elastic fibers 23A are formed, it is easy to form gaps S between the elastic fibers 23A. Therefore, even if the waist elastic members 23 and 33 are compressed by the convex mold forming the side joint SS and the welded portion 50, the gaps S can be compressed to form a margin (not to be broken by the convex mold), so that the waist elastic members 23 and 33 can be prevented from being cut.

[0196] In addition, since the elastic fibers 23A are used, it is easy to make the thickness of the waist elastic members 23 and 33 partially different by utilizing the aggregation of the elastic fibers 23A. Fig. 10AAs shown, the waist elastic members 23, 33 have a large diameter portion 23B having an outer diameter of the first outer diameter d23B and a small diameter portion 23C (groove portion) having an outer diameter d23C smaller than the first outer diameter d23B. Thus, when the large diameter portion (23B) of the elastic members 23, 33 is located between the welded portion pair 51, the large diameter portion is strongly sandwiched between the welded portion pair 51, and the waist elastic members 23, 33 can be prevented from falling off from the welded portion pair 51.

[0197] In addition, 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. As a result, the surface area of ​​the waist elastic members 23, 33 is increased, the friction force with the sheet is improved (it is easy to be entangled with the fiber of the sheet), and the waist elastic members 23 can be prevented from falling off from the welded portion pair 50. Therefore, the elasticity of the waist portions 20, 30 can be ensured.

[0198] In addition, it is preferred that the waist elastic members 23, 33 do not contain pigment (such as white titanium oxide) but are transparent. As a result, the surface of the waist elastic members 23 is smooth, which can reduce the friction between the skin side sheets 21, 31 and the non-skin side sheets 22, 32 and the waist elastic members 23, 33. Therefore, it is easy to expand the waist circumference 20, 30.

[0199] The above embodiments are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The present invention can of course be changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof.

[0200] Description of Reference Numerals

[0201] 1Diapers (absorbent articles),

[0202] 10 absorbent body, 11 absorbent core, 12 top sheet,

[0203] 13 back sheet, 14 outer sheet, 15 leg elastic member,

[0204] 16 leak-proof wall elastic member,

[0205] 20 ventral waist circumference,

[0206] 21 skin side sheet (sheet), 22 non-skin side sheet (sheet),

[0207] 23 waist elastic member (elastic member, first elastic member),

[0208] 23A elastic fiber, 24 fold back,

[0209] 30 back waist, 30E extension,

[0210] 31 skin side sheet (sheet), 32 non-skin side sheet (sheet),

[0211] 33 waist elastic member (elastic member), 34 folded portion,

[0212] SS side joint,

[0213] 50 welding part,

[0214] 60 tensile testing machine, 61 fixture, 62 fixture,

[0215] 70 Lubricants,

[0216] T test piece.

Claims

1. An absorbent article having an up-down direction and a left-right direction intersecting each other, The absorbent article comprises an absorbent core, a ventral waistline portion and a dorsal waistline portion. At least one of the ventral waistline portion and the dorsal waistline portion has a stretchable region, and the stretchable region is provided with an elastic member that can stretch in the left-right direction, characterized in that: At least a portion of the stretchable region is used as a test piece, The value obtained by dividing the force measured when the test piece is stretched in the horizontal direction to 84% of the length at the maximum stretch at a speed of 50000 mm / min by the width of the test piece in the vertical direction is set as a first measured value, The value obtained by dividing the force measured when the test piece is stretched in the left-right direction to 84% of the maximum stretch at a speed of 500 mm / min by the width is set as a second measured value, A value obtained by dividing the first measured value by the second measured value is smaller than 1.

2.

2. The absorbent article according to claim 1, wherein In a test in which the test piece is stretched at a speed of 50,000 mm / min to a length of 84% of the maximum stretch and then retracted to a length of 66% of the maximum stretch after 15 seconds from the start of stretching, The value obtained by dividing the force measured when the test piece is contracted to 66% of the length at the maximum extension by the width is set as a third measured value, A value obtained by dividing the force measured at 585 seconds after the test piece was contracted to 66% of the length at the maximum extension by the width is set as a fourth measured value, A value obtained by dividing the fourth measured value by the third measured value is 0.95 or more.

3. The absorbent article according to claim 1 or 2, characterized in that: The absorbent article is a shorts-type absorbent article in which the ventral waistline portion and the dorsal waistline portion are joined at both sides in the left-right direction by a pair of side joining portions. The test piece is a portion of the ventral waistline portion and the dorsal waistline portion that are joined into a ring shape by the side joining portion and is located above the center of the side joining portion in the vertical direction.

4. The absorbent article according to claim 1 or 2, characterized in that: In the stretchable region, the elastic member is disposed between a pair of sheets joined by a plurality of welded portions. The elastic member is sandwiched between two of the welded portions adjacent to each other in the up-down direction in a state contracted in the left-right direction, thereby regulating the position of the pair of sheets in the up-down direction.

5. The absorbent article according to claim 4, characterized in that The absorbent article is a shorts-type absorbent article in which the ventral waistline portion and the dorsal waistline portion are joined at both sides in the left-right direction by a pair of side joining portions. In at least one of the ventral waistline portion and the dorsal waistline portion, A plurality of elastic members are arranged at intervals in the up-down direction. All the elastic members overlapping the side joint portions in the up-down direction are sandwiched between two adjacent welded portions in the up-down direction in a state contracted in the left-right direction, thereby restricting the up-down position relative to the pair of sheets.

6. The absorbent article according to claim 4, characterized in that The plurality of welded portions include a plurality of welded portion pairs, and the welded portion pairs are located adjacent to each other in the up-down direction and sandwich the elastic member. The plurality of welded portion pairs include a first welded portion pair and a second welded portion pair located closer to the center in the left-right direction than the first welded portion pair. In the second pair of welded portions, the length in the up-down direction between the welded portions sandwiching the elastic member is greater than that of the first pair of welded portions.

7. The absorbent article according to claim 4, characterized in that The plurality of welded portions include a plurality of welded portion pairs, and the welded portion pairs are located adjacent to each other in the up-down direction and sandwich the elastic member. 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. In the fourth pair of welded portions, the length of the welded portions in the left-right direction is smaller than that of the third pair of welded portions.

8. The absorbent article according to claim 4, wherein: The stretchable region includes a first elastic member and a second elastic member adjacent to each other at a distance in the up-down direction. The plurality of welded parts include: a first welded portion, the first welded portion being adjacent to the first elastic member; as well as a second welded portion, the second welded portion being located at a center portion in the up-down direction between the first elastic member and the second elastic member, The first welded portion has a stronger weld strength than the second welded portion.

9. The absorbent article according to claim 4, wherein: When the telescopic region is extended in the left-right direction, A length in the up-down direction between two welded portions adjacent to each other in the up-down direction and sandwiching the elastic member is greater than a length in the up-down direction of the elastic member.

10. The absorbent article according to claim 1 or 2, characterized in that: The absorbent article is a shorts-type absorbent article in which the ventral waistline portion and the dorsal waistline portion are joined at both sides in the left-right direction by a pair of side joining portions. The absorbent article comprises an outer body and an absorbent body including the absorbent core. In the unfolded state of the absorbent article, The stretchable region includes a region where the number of sheets stacked on the exterior body is two layers of a pair of sheets sandwiching the elastic member.

11. The absorbent article according to claim 1 or 2, characterized in that: The absorbent article is a shorts-type absorbent article in which the ventral waistline portion and the dorsal waistline portion are joined at both sides in the left-right direction by a pair of side joining portions. The absorbent article comprises an absorbent body, wherein the absorbent body includes the absorbent core. A folded portion is provided at least one of the ventral waistline portion and the dorsal waistline portion, wherein the upper end portion of at least one of the pair of sheets sandwiching the elastic member is folded downward in the vertical direction. A region where no adhesive is disposed is provided between the upper end of the absorbent body and the lower end of the folded-back portion.

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

13. The absorbent article according to claim 1 or 2, characterized in that: A value obtained by dividing the first measurement value by the second measurement value when the back waistline portion is used as the test piece is smaller than a value obtained by dividing the first measurement value by the second measurement value when the ventral waistline portion is used as the test piece.

14. The absorbent article according to claim 1 or 2, characterized in that: A value obtained by dividing the first measurement value by the second measurement value when the ventral waistline portion is used as the test piece is smaller than a value obtained by dividing the first measurement value by the second measurement value when the dorsal waistline portion is used as the test piece.

15. The absorbent article according to claim 1 or 2, characterized in that: The absorbent article is a shorts-type absorbent article in which the ventral waistline portion and the dorsal waistline portion are joined at both sides in the left-right direction by a pair of side joining portions. In the unfolded state of the absorbent article, the average unit area weight of the absorbent core is lower at a portion of the absorbent core overlapping the dorsal waistline portion in the thickness direction than at a portion of the absorbent core overlapping the ventral waistline portion in the thickness direction.

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